A system and method for evaluating wear of a transmission clutch based on shift loads

Abstract

This invention discloses a transmission clutch wear assessment system and method based on shift load. It collects load spectrum data during shifting at each gear in the transmission, determines the wear amount and recent wear rate of the clutch discs at each gear based on the mapping relationship between the load spectrum data and the change in clutch disc wear, and assesses the time it takes for the clutch wear to reach the failure threshold, thereby determining the remaining service life of the clutch. This invention allows for the preparation of spare parts and tools for replacement before clutch friction disc failure, thus reducing downtime, shortening maintenance cycles, and minimizing the impact of shutdowns.

Description

Technical Field

[0001] This invention relates to the field of transmission safety assessment technology, specifically to a transmission clutch wear assessment system and method based on shift load. Background Technology

[0002] The clutch is a core component of the transmission. The transmission's starting, shifting, and direction-changing functions rely on the engagement and disengagement of the clutch. During engagement and disengagement, the internal friction plates inevitably slip, resulting in normal wear. Over time, the wear on the clutch friction plates gradually worsens. When the wear reaches its limit and is not replaced in time, it will lead to clutch slippage, reduced transmission efficiency, and transmission failure. In more severe cases, it may force the entire vehicle to be shut down for repairs, resulting in greater economic losses.

[0003] Therefore, a method is needed to detect the wear of the friction plates inside the clutch, assess the health of the clutch based on the wear of the friction plates, and prepare to replace the friction plates before the wear reaches the failure threshold, so as to shorten the maintenance cycle, avoid downtime due to failure, and reduce the impact of shutdown.

[0004] In existing technologies, the clutch friction coefficient is calculated by analyzing parameters during clutch engagement to determine the wear of the friction plates. The clutch friction coefficient is related to parameters such as clutch pressure, lubricating oil temperature, and clutch slip. These parameters often change during clutch engagement. Therefore, calculating the friction coefficient is challenging. Furthermore, existing technologies do not fully consider the influence of these parameters when calculating the clutch friction coefficient, resulting in significant errors in the calculation results.

[0005] The remaining life of the clutch is assessed based on real-time and cumulative wear per unit mileage, and then on the total designed wear of the clutch. Construction machinery vehicles often perform repetitive, cyclical operations with significant load variations. Under heavy load conditions, the clutch wears more easily. This technology does not consider the impact of load on wear and therefore cannot be widely applied to construction machinery vehicles.

[0006] By adding a device that can measure the working stroke, the wear travel of the clutch driven plate friction lining can be determined, thereby enabling the monitoring of clutch wear. However, the high operating temperature and speed of the clutch, coupled with the limited space, place extremely high demands on the durability, reliability, and installation of the sensor. Therefore, the implementation cost of this technology is high, making it difficult to promote its application in mass-produced vehicles. Summary of the Invention

[0007] The purpose of this invention is to provide a transmission clutch wear assessment system and method based on shift load. Without adding sensors, it collects load spectrum data during gear shifts in each gear of the transmission. Based on the mapping relationship between the load spectrum data and the change in clutch disc wear, it determines the wear amount and recent wear rate of the clutch discs in each gear, and assesses the time it takes for the clutch wear to reach the failure threshold, thereby determining the remaining service life of the clutch. Before the clutch friction discs fail, spare parts and tools are prepared in advance for replacement, thereby reducing downtime due to malfunctions, shortening the maintenance cycle, and minimizing the impact of downtime.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] This invention provides a transmission clutch wear assessment system based on shift load, comprising:

[0010] The power source, connected to the gearbox and power source control unit, is used to provide power for the rotation of the gearbox;

[0011] The power source control unit is connected to the power source and transmission control unit and is used to monitor the status of the power source and obtain information such as the current speed, actual torque and running time of the power source.

[0012] The gearbox is connected to the power source and is used to receive the torque and speed transmitted by the power source; the gearbox is equipped with a clutch, and the starting, shifting and reversing of the gearbox are realized by the engagement and disengagement of the clutch;

[0013] The transmission control unit receives signals from the speed sensor to obtain the transmission input speed; it receives signals from the power source control unit to obtain information on the power source's speed, torque, and running time; and it sends control signals to the proportional solenoid valve to control the engagement and disengagement of the clutch.

[0014] The proportional solenoid valve receives control signals from the transmission control unit and controls the engagement and disengagement of the clutch;

[0015] The speed sensor monitors the input speed of the transmission and transmits the speed signal to the transmission control unit.

[0016] Preferably, if the power source is an electric motor, then the power source control unit is a motor control unit, and the motor is rigidly connected to the gearbox;

[0017] If the power source is an engine, then the power source control unit is the engine control unit, and the engine and the transmission are connected through a torque converter or directly rigidly connected.

[0018] Preferably, the power source control unit and the transmission control unit communicate via CAN, and the power source control unit transmits the current speed, actual torque and running time information of the power source to the transmission control unit.

[0019] Preferably, when the power source is an electric motor or an engine that is directly and rigidly connected to the gearbox, the gearbox input speed is obtained directly from the signal of the power source control unit.

[0020] This invention also provides an evaluation method for a transmission clutch wear assessment system based on shift load, comprising:

[0021] Determine the operating point within the shift load spectrum to which the input load before the gearbox clutch shifts, and the total number of shifts at that operating point. The input load includes the gearbox input speed. and transmission input torque The shift load spectrum is formed by the operating points of the transmission with different combinations of input speed and input torque.

[0022] After the clutch wear assessment calculation conditions are met, the total clutch wear is calculated based on the total number of gear shifts at the load spectrum operating point.

[0023] The recent wear rate of the clutch is calculated based on the cumulative number of gear shifts over a preset time.

[0024] The remaining service life of the clutch is calculated based on the total wear of the clutch and the recent wear rate of the clutch.

[0025] Preferably, the shift load spectrum is:

[0026] The operating range of the transmission input speed is divided into sections at certain intervals. The transmission input torque operating range is divided into several intervals. Each interval forms a region with × Transmission shift load spectrum at various operating conditions.

[0027] Preferably, determining the operating point in the shift load spectrum to which the input load before the gearbox clutch shifts and the total number of shifts at the operating point includes:

[0028] When the transmission control unit sends a control signal to the proportional solenoid valve to control the engagement of other clutches Cl1, it confirms that the transmission is shifting gears.

[0029] Obtain the transmission input speed before the shift begins and input torque ;

[0030] When the solenoid valve control signal sent by the transmission control unit confirms that the clutch Clu1 is engaged, the gear shift is considered complete.

[0031] After shifting gears, adjust according to the input RPM. and input torque The specific value range is determined by the operating point in the shift load spectrum of the corresponding clutch Clu1. subscript and These are the operating point numbers for the input speed and input torque, respectively, where 1 ≤ ≤ ,1≤ ≤ ;

[0032] Update the corresponding load spectrum conditions. Total number of gear shifts .

[0033] Preferably, the transmission input speed before the shift begins is obtained via a speed sensor. If the power source is an electric motor or an engine directly connected to the gearbox, the gearbox input speed before shifting begins is obtained based on the signal from the power source control unit. .

[0034] Preferably, if the drive source is a drive motor, the actual torque of the motor is read from the CAN signal sent by the motor control unit and used as the input torque of the gearbox. ;

[0035] If the drive source is an engine and it is not equipped with a torque converter, read the actual engine torque percentage from the CAN signal sent by the engine control unit. And through the formula The current actual torque of the engine is calculated. As the input torque of the transmission ;in, This is the engine's maximum torque value, obtained by querying the engine's performance parameters;

[0036] If the drive source is an engine and it is equipped with a hydraulic torque converter, the pump impeller speed of the hydraulic torque converter is the same as the engine speed. The pump impeller speed is determined based on the engine speed signal in the CAN signal sent by the engine control unit. According to the formula Turbine torque was calculated As the input torque of the transmission ;in, The torque ratio of the hydraulic torque converter. The torque coefficient is determined by referring to a table when the pump impeller speed is 1000 rpm.

[0037] Preferably, the calculation conditions for clutch wear assessment are as follows:

[0038] When the power source operating time in the power source control unit At that time, the conditions for clutch wear assessment and calculation are met.

[0039] Preferably, the calculation of the total clutch wear based on the total number of gear shifts at the load spectrum operating point is as follows:

[0040] ,

[0041] in, This is the assessment value for the total wear of the clutch. For the clutch at the operating point The wear amount after 1000 cycles was obtained from experimental testing.

[0042] Preferably, the calculation of the clutch recent wear rate based on the cumulative number of gear shifts over a preset time is as follows:

[0043] ,

[0044] in, This is the assessment value for the recent wear rate of the clutch. The cumulative number of gear shifts over a preset time period, where the preset time period is 100 hours.

[0045] The cumulative number of gear shifts within the preset time is determined as follows:

[0046] Based on the power source operating time in the power source control unit ,statistics Load spectrum operating points within the time range The cumulative number of gear shifts within 100 hours .

[0047] Preferably, the calculation of the remaining service life of the clutch based on the total wear of the clutch and the recent wear rate of the clutch is as follows:

[0048] ,

[0049] in This is the estimated remaining service life value of the clutch. The maximum wear amount is determined by experimental testing to ensure that the clutch operates normally under maximum load conditions.

[0050] The beneficial effects of the technical solution of this invention are as follows:

[0051] This invention proposes a transmission clutch wear assessment system and method based on shift load. Without adding sensors, it collects load spectrum data during gear shifts in each gear of the transmission. Based on the mapping relationship between the load spectrum data and the change in clutch disc wear, it determines the wear amount and recent wear rate of the clutch discs in each gear, and estimates the time it takes for the clutch wear to reach the failure threshold, thereby determining the remaining service life of the clutch. This allows for the preparation of spare parts and tools for replacement before the clutch friction discs fail, thus reducing downtime, shortening the maintenance cycle, and minimizing the impact of shutdowns. Attached Figure Description

[0052] Figure 1 A schematic diagram of the gearbox clutch wear assessment system based on shift load provided by the present invention;

[0053] Figure 2 This is a schematic diagram of the transmission clutch wear assessment method based on shift load provided by the present invention;

[0054] Figure 3 This is a schematic diagram of the transmission clutch shift load acquisition process provided by the present invention;

[0055] Figure 4 This is a schematic diagram illustrating the activation and calculation process of the clutch wear assessment program provided by the present invention. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0057] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0058] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0059] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0060] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0061] It should be emphasized here that the step markers mentioned below are not a limitation on the order of the steps, but should be understood as meaning that the steps can be executed in the order mentioned in the embodiments, or in a different order than in the embodiments, or several steps can be executed simultaneously.

[0062] This invention proposes a transmission clutch wear assessment system based on shift load, such as... Figure 1 As shown, the system consists of a power source, a PCU (Power Control Unit), a gearbox, a TCU (Transmission Control Unit), a proportional solenoid valve, and a speed sensor.

[0063] The power source is connected to the gearbox and PCU, and provides power for the rotation of the gearbox.

[0064] It should be noted that if the power source is an electric motor, then the PCU is an MCU (Motor Control Unit), and the motor and the gearbox are rigidly connected; if the power source is an engine, then the PCU is an ECU (Engine Control Unit), and the engine and the gearbox can be connected via a torque converter or directly rigidly connected.

[0065] The PCU connects to the power source and the TCU. The PCU is used to monitor the status of the power source and obtain information such as the current speed, actual torque, and running time.

[0066] The PCU and TCU communicate via CAN (Controller Area Network), with the PCU transmitting information such as the current speed, actual torque, and running time of the power source to the TCU.

[0067] The gearbox is connected to the power source and receives the torque and speed transmitted by the power source.

[0068] The transmission contains a wet clutch, which engages and disengages to enable functions such as starting, shifting gears, and reversing. The engagement and disengagement of the wet clutch are controlled by a proportional solenoid valve.

[0069] The TCU receives signals from the speed sensor to obtain the transmission input speed. The TCU also receives CAN signals from the PCU to determine information such as the power source's speed, torque, and operating time. The TCU sends control signals to the proportional solenoid valve to control the engagement and disengagement of the clutch.

[0070] The proportional solenoid valve receives control signals from the TCU and controls the engagement and disengagement of the clutch.

[0071] The speed sensor is mounted on the transmission to monitor the transmission input speed and transmits the speed signal to the TCU. When the power source is an electric motor or an engine directly connected to the transmission, the transmission input speed can be obtained from the PCU's CAN signal, eliminating the need for a speed sensor.

[0072] Based on the above-described evaluation system, the transmission clutch wear evaluation method provided by this invention, such as... Figure 2 As shown, it includes the following steps:

[0073] S1. Determine the operating point in the shift load spectrum to which the input load before the gearbox clutch shifts, and the total number of shifts at that operating point. The input load includes the gearbox input speed. and transmission input torque The clutch shift load spectrum is formed by the operating points of the gearbox under different combinations of input speed and input torque.

[0074] S2. Calculate the total clutch wear based on the total number of gear shifts at the load spectrum operating point;

[0075] S3. Calculate the recent wear rate of the clutch based on the cumulative number of gear shifts over a preset time.

[0076] S4. Calculate the remaining service life of the clutch based on the total wear of the clutch and the recent wear rate of the clutch.

[0077] In this invention, the operating point in the shift load spectrum to which the input load before the gearbox clutch shifts belongs, and the total number of shifts at that operating point, are determined. For details, please refer to [link to relevant documentation]. Figure 3 ,include:

[0078] (1) When the TCU sends a control signal to the proportional solenoid valve to control the engagement of other clutches Clu1, the gearbox is confirmed to shift gears.

[0079] (2) Obtain the gearbox input speed before the gear shift begins It should be noted that the transmission input speed before the shift begins is obtained through a speed sensor. If the power source is an electric motor or an engine directly connected to the transmission, the transmission input speed before the shift begins can be obtained from the PCU's CAN signal. ;

[0080] (3) Determine the input torque of the transmission before shifting begins. ,

[0081] In step (3), if the driving source is a drive motor, read the actual motor torque from the CAN signal sent by the MCU. The actual motor torque at this time is the input torque of the gearbox. .

[0082] If the drive source is an engine and it is not equipped with a torque converter, read the actual engine torque percentage from the CAN signal sent by the ECU. And through the formula The current actual torque of the engine is calculated. ,in, This is the engine's maximum torque value, which can be obtained by consulting the engine performance parameters. The actual engine torque at this point... This refers to the input torque of the transmission. .

[0083] If the drive source is an engine and it is equipped with a torque converter, the pump impeller speed of the torque converter is the same as the engine speed. The pump impeller speed can be determined based on the engine speed signal in the CAN signal sent by the ECU. The turbine speed of the hydraulic torque converter is determined by a speed sensor. The turbine torque was calculated according to the formula. ,in, The torque ratio of the hydraulic torque converter. The torque coefficient at a pump impeller speed of 1000 rpm can be determined by referring to a table. The calculated turbine torque... This is the input torque of the transmission. .

[0084] (4) When the clutch Clu1 is confirmed to be engaged according to the solenoid valve control signal sent by the TCU, the gear shift is considered to be complete.

[0085] (5) Divide the operating range of the gearbox input speed into a certain interval. The transmission input torque operating range is divided into several intervals. Each interval forms a region with × Transmission shift load spectrum at various operating conditions.

[0086] (6) After shifting gears, adjust the speed according to the input speed. and input torque The specific value range determines the operating point in the shift load spectrum of the corresponding clutch Clu1. , where 1≤ ≤ ,1≤ ≤ .

[0087] (7) Update the corresponding load spectrum conditions Total number of gear shifts .

[0088] In this invention, when set conditions are met, the clutch wear assessment calculation program within the TCU is activated. The specific process is as follows: Figure 4 As shown.

[0089] In this invention, the operating time of the power source within the PCU is used as the basis for the calculation. ,statistics Load spectrum operating points within the time range The cumulative number of gear shifts within 100 hours Load spectrum operating point Total number of gear shifts And the cumulative number of gear shifts within 100 hours Stored in the non-volatile ferroelectric memory area of ​​the TCU.

[0090] When the power source inside the PCU runs for At that time, the clutch wear assessment calculation program in the TCU is activated.

[0091] In this invention, the total wear of the clutch is calculated based on the total number of gear shifts at the load spectrum operating point, specifically as follows:

[0092] According to the formula The total wear of clutch Clu1 was calculated, where, This is the assessment value for the total wear of the clutch. For clutch Clu1 at the operating point The wear amount after 1000 cycles was obtained from experimental testing.

[0093] In this invention, the recent wear rate of the clutch is calculated based on the cumulative number of gear shifts over a preset time, specifically as follows:

[0094] According to the formula The wear rate of clutch Clu1 per 100 hours was calculated, where, The preset time for evaluating the recent wear rate of the clutch is 100 hours, which is the evaluation value for the clutch in this invention.

[0095] In this invention, the remaining service life of the clutch is calculated based on the total wear of the clutch and the recent wear rate of the clutch, specifically as follows:

[0096] According to the formula The remaining service life assessment value of clutch Clu1 was calculated, where This is the remaining service life assessment value for clutch Clu1. The maximum wear amount is determined by experimental testing to ensure that clutch Clu1 can operate normally under maximum load conditions.

[0097] The above system and method can be used to calculate and determine clutch wear assessment, evaluate the remaining service life of the clutch based on the wear condition, and prepare for the replacement of friction plates in advance when necessary, so as to shorten the maintenance cycle and reduce the impact of downtime.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A transmission clutch wear assessment system based on shift load, characterized in that, include: The power source, connected to the gearbox and power source control unit, is used to provide power for the rotation of the gearbox; The power source control unit is connected to the power source and transmission control unit and is used to monitor the status of the power source and obtain information such as the current speed, actual torque and running time of the power source. The gearbox is connected to the power source and is used to receive the torque and speed transmitted by the power source; the gearbox is equipped with a clutch, and the starting, shifting and reversing of the gearbox are realized by the engagement and disengagement of the clutch; The transmission control unit receives signals from the speed sensor to obtain the transmission input speed; It receives signals from the power source control unit to obtain information on the power source's speed, torque, and running time. And send control signals to the proportional solenoid valve to control the engagement and disengagement of the clutch; The proportional solenoid valve receives control signals from the transmission control unit and controls the engagement and disengagement of the clutch; The speed sensor monitors the input speed of the transmission and transmits the speed signal to the transmission control unit.

2. The gearbox clutch wear assessment system based on shift load according to claim 1, characterized in that, If the power source is an electric motor, then the power source control unit is the motor control unit, and the motor is rigidly connected to the gearbox; If the power source is an engine, then the power source control unit is the engine control unit, and the engine and the transmission are connected through a torque converter or directly rigidly connected.

3. The gearbox clutch wear assessment system based on shift load according to claim 1, characterized in that, The power source control unit and the transmission control unit communicate via CAN. The power source control unit transmits the current speed, actual torque, and running time information of the power source to the transmission control unit.

4. The gearbox clutch wear assessment system based on shift load according to claim 1, characterized in that, When the power source is an electric motor or an engine that is directly and rigidly connected to the gearbox, the gearbox input speed is obtained directly from the signal of the power source control unit.

5. An evaluation method based on the gearbox clutch wear evaluation system based on shift load according to any one of claims 1 to 4, characterized in that, include: Determine the operating point within the shift load spectrum to which the input load before the gearbox clutch shifts, and the total number of shifts at that operating point. The input load includes the gearbox input speed. and transmission input torque The shift load spectrum is formed by the operating points of the transmission with different combinations of input speed and input torque. After the clutch wear assessment calculation conditions are met, the total clutch wear is calculated based on the total number of gear shifts at the load spectrum operating point. The recent wear rate of the clutch is calculated based on the cumulative number of gear shifts over a preset time. The remaining service life of the clutch is calculated based on the total wear of the clutch and the recent wear rate of the clutch.

6. The evaluation method according to claim 5, characterized in that, The shift load spectrum is: The operating range of the transmission input speed is divided into sections at certain intervals. The transmission input torque operating range is divided into several intervals. Each interval forms a region with × Transmission shift load spectrum at various operating conditions.

7. The evaluation method according to claim 6, characterized in that, Determining the operating point in the shift load spectrum to which the input load before the gearbox clutch shifts, and the total number of shifts at that operating point, includes: When the transmission control unit sends a control signal to the proportional solenoid valve to control the engagement of other clutches Cl1, it confirms that the transmission is shifting gears. Obtain the transmission input speed before the shift begins and input torque ; When the solenoid valve control signal sent by the transmission control unit confirms that the clutch Clu1 is engaged, the gear shift is considered complete. After shifting gears, adjust according to the input RPM. and input torque The specific value range is determined by the operating point in the shift load spectrum of the corresponding clutch Clu1. subscript and These are the operating point numbers for the input speed and input torque, respectively, where 1 ≤ ≤ ,1≤ ≤ ; Update the corresponding load spectrum conditions. Total number of gear shifts .

8. The evaluation method according to claim 7, characterized in that, The transmission input speed before the gear shift begins is obtained via a speed sensor. If the power source is an electric motor or an engine directly connected to the gearbox, the gearbox input speed before shifting begins is obtained based on the signal from the power source control unit. .

9. The evaluation method according to claim 7, characterized in that, If the drive source is a drive motor, the actual torque of the motor is read from the CAN signal sent by the motor control unit and used as the input torque of the gearbox. ; If the drive source is an engine and it is not equipped with a torque converter, read the actual engine torque percentage from the CAN signal sent by the engine control unit. And through the formula The current actual torque of the engine is calculated. As the input torque of the transmission ;in, This is the engine's maximum torque value, obtained by querying the engine's performance parameters; If the drive source is an engine and it is equipped with a hydraulic torque converter, the pump impeller speed of the hydraulic torque converter is the same as the engine speed. The pump impeller speed is determined based on the engine speed signal in the CAN signal sent by the engine control unit. According to the formula Turbine torque was calculated As the input torque of the transmission ;in, The torque ratio of the hydraulic torque converter. The torque coefficient is determined by referring to a table when the pump impeller speed is 1000 rpm.

10. The evaluation method according to claim 7, characterized in that, The calculation conditions for clutch wear assessment are as follows: When the power source operating time in the power source control unit At that time, the conditions for clutch wear assessment and calculation are met.

11. The evaluation method according to claim 10, characterized in that, The total clutch wear is calculated based on the total number of gear shifts at the load spectrum operating point, as follows: ， in, This is the assessment value for the total wear of the clutch. For the clutch at the operating point The wear amount after 1000 cycles was obtained from experimental testing.

12. The evaluation method according to claim 11, characterized in that, The clutch recent wear rate is calculated based on the cumulative number of gear shifts over a preset time, as follows: ， in, This is the assessment value for the recent wear rate of the clutch. The cumulative number of gear shifts over a preset time period, where the preset time period is 100 hours. The cumulative number of gear shifts within the preset time is determined as follows: Based on the power source operating time in the power source control unit ,statistics Load spectrum operating points within the time range The cumulative number of gear shifts within 100 hours .

13. The evaluation method according to claim 12, characterized in that, The remaining service life of the clutch is calculated based on the total wear of the clutch and the recent wear rate of the clutch, as follows: ， in This is the estimated remaining service life value of the clutch. The maximum wear amount is determined by experimental testing to ensure that the clutch operates normally under maximum load conditions.

Images