A bench-offline detection method for an automotive hydro-mechanical continuously variable transmission bridge

Abstract

A bench-offline detection method for an automotive hydraulic-mechanical continuously variable transmission bridge of the present invention increases the transmission speed, lubrication, main flow path, and AB pump pressure, and tests the functions of shifting, four-wheel drive, differential lock, and high and low gears; with the transmission in the first gear, engage and then disengage the PTO upper clutch, engage and disengage the second gear at 0 rpm, engage and disengage the third gear at 0 rpm, and test the clutch pressure and current curves for each state to meet the standards; with the vehicle parked, adjust the rear axle brake clearance counterclockwise to the maximum, release the parking brake, set the input speed, reverse, high gear command, transmission ratio to 0.1, and differential lock command to engaged, operate the left rear axle brake adjustment lever, rotate counterclockwise 3 to 4 turns after the engine torque increases, set the differential lock command to disengaged, perform the same operation on the right rear axle brake, screw on the rear axle brake housing, and test the oil pump efficiency; test the hydraulic displacement and current curves of the AB pump at different swing angles, and determine whether the current and pressure at the K point of the gear and PTO clutch meet the standards.

Description

Technical Field

[0001] The present invention relates to the field of gearbox detection, and specifically to a bench off-line detection method for an automotive hydro-mechanical continuously variable transmission bridge. Background Art

[0002] Developing intelligent agricultural machinery equipment is an important direction for the transformation and upgrading of agricultural mechanization and the agricultural machinery industry. The automotive hydro-mechanical continuously variable transmission, abbreviated as HMCVT, as an important component of the intelligent upgrading of large-horsepower tractors, forms a transmission bridge after the gearbox and the rear axle are assembled together. The oil circuits of the gearbox and the rear axle are interconnected, and the transmission bridge is subjected to off-line detection as a whole. The ex-factory of each HMCVT transmission bridge requires strict off-line detection procedures to further ensure the safety and reliability of the product.

[0003] Since the HMCVT transmission bridge is positioned for large-horsepower tractors, its mechanical structure and software control logic are very complex. In order to ensure the normal operation of each function of the HMCVT transmission bridge, there are many items that need to be detected off-line for the HMCVT transmission bridge. However, there is currently no complete and standardized bench off-line detection method, so the failure rate of the HMCVT transmission bridge cannot be controlled. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a bench off-line detection method for an automotive hydro-mechanical continuously variable transmission bridge, which can more comprehensively verify the safety and reliability of the transmission bridge, thereby reducing the failure rate of the transmission bridge.

[0005] The present invention is realized through the following technical solutions:

[0006] A bench off-line detection method for an automotive hydro-mechanical continuously variable transmission bridge includes the following steps:

[0007] Step 1, drive the speed of the transmission bridge to rise uniformly. When the lubrication pressure, the main circuit pressure, and the pressures on both sides of the volume speed regulation circuit A and B in the fixed-displacement motor-variable pump gradually increase, perform a shift function test, a four-wheel drive function test, a differential lock function test, and a high-low gear function test in sequence;

[0008] Step 2: Return all gears of the transmission bridge to neutral. First, engage the clutch on the PTO in the 1st gear. When the speed and status of the PTO output meet the standards, disengage the clutch on the PTO. After the speed of the PTO output drops to 0, engage the clutch on the PTO in the 2nd gear. When the speed and status of the PTO output meet the standards, disengage the clutch on the PTO. After the speed of the PTO output drops to 0, engage the clutch on the PTO in the 3rd gear. When the speed and status of the PTO output meet the standards, conduct the clutch pressure and current curve test.

[0009] Step 3: First, put the transmission bridge in the parking state, then unscrew the rear axle brake housing, adjust the rear axle brake clearance counterclockwise to the maximum value, and then release the parking state of the transmission bridge. Sequentially set the input speed, reverse command, high gear command, transmission ratio to 0.1, and differential lock command to engaged for the transmission bridge. Then rotate the left rear axle brake adjusting rod clockwise. When the engine torque increases by 20 - 30 N·m, rotate the left rear axle brake adjusting rod counterclockwise for 3 - 4 turns. Immediately set the differential lock command to disengaged, rotate the right rear axle brake adjusting rod clockwise. When the engine torque increases by 20 - 30 N·m, rotate the right rear axle brake adjusting rod counterclockwise for 3 - 4 turns, screw on the rear axle brake housing, and finally conduct the oil pump efficiency test.

[0010] Step 4: First, conduct the hydraulic displacement and current curve tests for both sides A and B of the volume speed control circuit in the fixed-displacement motor - variable pump at different swashplate angles. When the K-point current and corresponding pressure of the gear clutch meet the standards, determine whether the K-point current and corresponding pressure of the PTO clutch meet the standards to complete the bench off-line inspection of the automotive hydro-mechanical continuously variable transmission bridge.

[0011] Preferably, the shift function test described in Step 1 is carried out as follows:

[0012] Set the input speed for the transmission bridge. After there is no error message from the controller connected to the transmission bridge, set the transmission ratio of the transmission bridge to 0, set the parking release command, set the maximum torque value of the transmission bridge to 8000 N·m, and at the same time make the clutch signal be not depressed. Then set the high gear command. After the pressure and status of each gear meet the standards, proceed to the subsequent steps;

[0013] Set the transmission ratio of the transmission bridge to -0.1. After the pressure and status of each gear meet the standards, proceed to the subsequent steps;

[0014] Set the transmission ratio of the transmission bridge to -0.3. After the pressure and status of each gear meet the standards, proceed to the subsequent steps;

[0015] Set the transmission ratio of the transmission bridge to -0.7, and perform the subsequent steps after the pressure and status of each gear meet the standards;

[0016] Set the transmission ratio of the transmission bridge to 0. After the transmission bridge stops rotating, first set the reverse command, and then set the transmission ratio of the transmission bridge to 0.1. Perform the subsequent steps after the pressure and status of each gear meet the standards;

[0017] Set the transmission ratio of the transmission bridge to 0.3, and check whether the pressure and status of each gear meet the standards.

[0018] Preferably, the four-wheel drive function test described in step 1 is carried out as follows:

[0019] Set the transmission ratio of the transmission bridge to 0. After the transmission bridge stops rotating, set the forward command, and then sequentially set the transmission ratio of the transmission bridge to -0.1 and the four-wheel drive command to engaged. When the pressure reading and the four-wheel drive gear status meet the standards, set the four-wheel drive command to disengaged, and check whether the four-wheel drive gear pressure reading and status meet the standards.

[0020] Preferably, the differential lock function test described in step 1 is carried out as follows:

[0021] Give the transmission bridge a forward command, and then sequentially set the transmission ratio of the transmission bridge to -0.1 and the differential lock command to engaged. After the differential lock status meets the standards, set the differential lock command to disengaged, and check whether the differential lock status meets the standards.

[0022] Preferably, the high and low gear function test described in step 1 is carried out as follows:

[0023] Give the transmission bridge a forward command, and then sequentially set the transmission ratio of the transmission bridge to 0 and the high gear command. After the gear position, pressure, and status meet the standards, give the transmission bridge the high gear command. After the position reading of the position sensor changes, first give the transmission bridge the neutral gear command. After the gear position, pressure, and status meet the standards, give the transmission bridge the low gear command, and check whether the gear position, pressure, and status meet the standards.

[0024] Preferably, the clutch pressure and current curve test described in step 2 is carried out as follows:

[0025] First, keep the oil temperature in the hydraulic pump at 55 - 65 °C. After the gearbox bridge has no faults, repeat the shift function test process more than 20 times, and at the same time remove the air bubbles in the solenoid valve cavity. Then, sequentially set the transmission ratio of the gearbox bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral. Finally, let the first - gear clutch complete the following process:

[0026] The first - gear clutch obtains the self - learning start command, the first - gear clutch runs the self - learning start command, and the set current, actual current, and pressure of the first - gear clutch gradually increase synchronously. When the rotational speed deviation of the first - gear clutch exceeds 10 rpm, the first - gear clutch obtains the self - learning stop command, and the set current, actual current, and pressure of the first - gear clutch no longer change. Determine whether the corresponding curve of the first - gear clutch pressure and actual current meets the standard;

[0027] The hydraulic gear clutch, second - gear clutch, and reverse - gear clutch are all tested according to the same process as the first - gear clutch.

[0028] Preferably, the oil pump efficiency test in step 3 is carried out according to the following process:

[0029] When the oil temperature is 60 °C, first drive the gearbox bridge to rotate at a speed of 600 rpm, then drive the gearbox bridge to rotate at a speed of 700 rpm, and then drive the gearbox bridge to gradually rotate at a speed of 2000 rpm with a rising gradient of 100 rpm. Finally, lower the speed of the gearbox bridge back to 600 rpm in the reverse process, record the main oil circuit pressure, lubrication pressure, and external pipeline flow rate readings corresponding to each speed point, and calculate whether the oil pump efficiency at each speed point is within the standard range using the main oil circuit pressure, lubrication pressure, and external pipeline flow rate readings corresponding to each speed point.

[0030] Preferably, step 4 is carried out according to the following process: Test the hydraulic displacement and current curves corresponding to different swing angles on both the A - side and B - side of the volume speed - regulation circuit in the fixed - displacement motor - variable pump respectively:

[0031] Step 4a, first keep the oil temperature in the hydraulic pump at 55 - 65 °C. After the gearbox bridge has no faults, set the input speed for the gearbox bridge, and then sequentially set the transmission ratio of the gearbox bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral;

[0032] Step 4b: First, the A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning start instruction. The A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump operates the self-learning start instruction, generating 9 different hydraulic displacement values and 9 different swing angle values. The A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning stop instruction and no longer generates hydraulic displacement values and swing angle values. Then, the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning start instruction. The B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump operates the self-learning start instruction, generating 9 different hydraulic displacement values and 9 different swing angle values. The B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning stop instruction and no longer generates hydraulic displacement values and swing angle values;

[0033] Step 4c: Check whether the hydraulic displacement and current curves corresponding to different swing angles in the A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump and the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump meet the reference standards;

[0034] Step 4d: If the hydraulic displacement value P i generated by the A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump and the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump respectively and the corresponding fixed value P k meet the following relationship, the hydraulic displacement and current curve test is qualified; otherwise, repeat Step 4b until the relationship is met, and complete the test of the hydraulic displacement and current curve.

[0035] |P i - P k | / P k <0.05.

[0036] Preferably, in Step 4, judge whether the K-point current and the corresponding pressure of the gear clutch meet the standards according to the following process:

[0037] Step 41: First, make the oil temperature in the hydraulic pump be 55 - 65 °C. After the transmission bridge has no faults, set the input speed for the transmission bridge, and then sequentially set the transmission ratio of the transmission bridge to 0, set the forward instruction, set the parking instruction, set the high-low gear instruction to neutral, and set the driving instruction to neutral;

[0038] Step 42: The gear clutch obtains the self-learning start instruction, and the hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear perform self-learning in sequence. The hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear each generate different K-point currents and corresponding pressures, and respectively judge whether the K-point currents and corresponding pressures in the hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear meet the standards.

[0039] Preferably, in Step 4, judge whether the K-point current and the corresponding pressure of the PTO clutch meet the standards according to the following process:

[0040] First, keep the oil temperature in the hydraulic pump at 55 - 65 °C. After there is no fault in the transmission bridge, set the input speed for the transmission bridge. Then, successively set the transmission ratio of the transmission bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral;

[0041] In the normal mode gear position, keep the clutch on the PTO in the engaged state. After the speed output by the PTO is stable, keep the clutch on the PTO in the disengaged state;

[0042] The PTO clutch obtains the self - learning start command, generates different K - point currents and corresponding pressures. The PTO clutch obtains the self - learning stop command, no longer generates K - point currents and pressures, and judges whether the K - point currents and corresponding pressures in the PTO clutch meet the standards.

[0043] Compared with the prior art, the present invention has the following beneficial technical effects:

[0044] A bench-offline detection method for an automotive hydro-mechanical continuously variable transmission bridge. First, drive the transmission bridge to increase its rotational speed uniformly. When the lubrication pressure, the main flow path pressure, and the pressures on both the A side and the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump all gradually increase, it indicates that the detection is qualified. Then, the shift function test, four-wheel drive function test, differential lock function test, and high-low gear function test can be carried out in sequence. During the PTO function test, first return all gears to neutral, then engage the clutch in the 1st gear. According to the output speed and status, it can be judged whether it meets the standard. Then disengage the clutch, and the output speed drops to 0 to prevent the clutch from malfunctioning and causing the clutch to fail to disengage due to linkage. Then engage the clutch in the 2nd gear. According to the output speed and status, it can be judged whether it meets the standard. Disengage the clutch again, and the output speed drops to 0. Engage the clutch in the 3rd gear. When the output speed and status meet the standard, it indicates that the PTO function test is qualified, and then the clutch pressure and current curve test can be carried out. The subsequent tests need to be carried out under braking. Poor rear axle brake clearance will cause the braking to fail during the test. The controller, which is an external device, will detect the relative vehicle speed and display a fault, thus making the test impossible to proceed. Therefore, first put the transmission bridge in the parking state, then unscrew the rear axle brake housing, adjust its clearance counterclockwise to the maximum value, release the parking brake, and then set the input speed, reverse command, high gear command, transmission ratio of 0.1, and differential lock command to engaged in sequence. Then rotate the left rear axle brake adjusting rod clockwise. When the engine torque increases to a certain extent, rotate the left rear axle brake adjusting rod counterclockwise. Immediately set the differential lock command to disengaged and perform the same operation on the right rear axle brake. Finally, screw on the rear axle brake housing to ensure good braking. On this basis, the oil pump efficiency test, and the hydraulic displacement and current curve tests corresponding to both the A side and the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump at different swash angles can be carried out. When the K-point current and the corresponding pressure of the gear clutch meet the standard, finally judge whether the K-point current and the corresponding pressure of the PTO clutch meet the standard, and then the bench-offline detection of the automotive hydro-mechanical continuously variable transmission bridge can be completed. The detection items of the present invention are very comprehensive, and the transmission bridge is detected in all aspects. Through this bench-offline detection method, it can be verified in all aspects whether the continuously variable transmission bridge meets the offline requirements, greatly improving the safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of the overall offline detection of the automotive hydro-mechanical continuously variable transmission bridge described in the present invention.

[0046] Figure 2 It is a schematic connection diagram of a transmission bench and a transmission bridge in the prior art. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The present invention will be further described in detail below in conjunction with specific embodiments. The following description is an explanation of the present invention rather than a limitation thereof.

[0048] A bench-offline detection method for an automotive hydraulic mechanical continuously variable transmission bridge of the present invention mainly involves faults of electronic components, such as faults of various sensors, solenoid valves, pump bodies, and mechanical body assemblies. The functional detection and self-learning of the transmission bridge can be realized based on the integrated operation instruction interface in the CANape environment. As Figure 1 shown, some mechanical operations require direct operation by the operator. The specific process is as follows:

[0049] S1: Confirm the status of the HMCVT transmission, ensuring that all components of the HMCVT transmission are installed properly and the hydraulic oil filling condition meets the requirements;

[0050] S2: Ensure that the wiring harness of the transmission bench as Figure 2 shown is connected properly, that is, connect the operation platform to the transmission and the rear axle. The controller (abbreviated as TCU), the input-side variable-speed motor (a common motor can be used), the flow monitoring device, and the oil cooler are peripheral devices. Connect them to the transmission to make them in a fault-free state. If a fault occurs in the TCU, solve the fault reported by the TCU;

[0051] S3: Confirm that all sensors before starting are in good condition, that is, the voltage of the regulated power supply, the pressure signal, the rotational speed signal, and the temperature signal meet the reference standards. The current value of the regulated power supply shall not be higher than 2A, and during the normal operation of the transmission, the current value of the regulated power supply shall not be higher than 10A;

[0052] S4: Sequentially includes S41 and S42

[0053] S41: Confirm the lubrication pressure and the pressures on the A side and B side of the displacement speed regulation circuit of the fixed-displacement motor-variable pump,

[0054] The variable-speed motor at the input end simulates the engine. First, start the variable-speed motor at the input end to drive the transmission to rotate. When starting for the first time, the speed should not be too high, and then slowly increase to 500 rpm. During the process of the speed increasing to 500 rpm, observe the establishment of the lubrication pressure and the main flow path pressure of the transmission. Under normal circumstances, both the lubrication pressure and the main flow path pressure of the transmission increase with the increase in speed (the lubrication pressure is close to 0.5 bar; the pressures on both sides of the volume speed regulation circuit A and B in the fixed-displacement motor-variable pump are close to 25 bar). The volume speed regulation circuit A and B in the fixed-displacement motor-variable pump are abbreviated as AB pump. If the pressure does not increase within 30 s starting from the rotation of the transmission, the test should be stopped immediately to check the reason. If the pressure follows normally, increase the speed to 800 rpm. At this time, the lubrication pressure should not be lower than 0.5 bar, and the pressures on both sides of the volume speed regulation circuit A and B in the fixed-displacement motor-variable pump should not be lower than 25 bar. If the above parameters are not met, the reason should be checked. At the same time, during the process of the speed increasing and the pressure establishing, ensure that no new faults occur in the TCU.

[0055] S42: Confirm that all sensors after starting the vehicle are in good condition, that is, the regulated power supply voltage, pressure signal, speed signal, and temperature signal meet the existing reference standards;

[0056] S5: Shift function test

[0057] S51: Establish the system pressure;

[0058] First, set the input speed of the HMCVT to 1000 rpm. At this time, check the fault status of the TCU to ensure that there is no error message in the TCU; then perform the following presets: 1. Set the transmission ratio of the HMCVT to 0; set the parking brake release command; 2. Set the maximum torque value of the HMCVT to 8000 N·m; 3. Set the driving command to forward; 4. The clutch signal needs to be made, through unauthorized control, that the clutch signal is not depressed, that is, the signal is 1. The presets 1-4 do not have a sequential order and can be completed. After that, set the high / low gear command to high gear, and check the pressure readings and states of each gear to make them meet the existing reference standards.

[0059] All the above and subsequent mentioned commands are operated based on the canape integrated interface.

[0060] S52: Set the transmission ratio of the HMCVT to -0.1. It should be noted that in this application document, all the transmission ratios of the HMCVT are the ratio of the planet carrier speed to the engine input speed. A negative sign indicates that the rotation directions of the two are opposite, and a positive sign indicates that the rotation directions of the two are the same. At this time, only the hydraulic forward gear is in gear, and the transmission rotates in the forward direction. At this time, check the pressure readings and states of each gear to make them meet the existing reference standards;

[0061] S53: Set the transmission ratio of the HMCVT to -0.3. At this time, only the mechanical power gear position 1 is engaged, and the transmission rotates in the forward direction. Check the pressure readings and status of each gear position to make them meet the current existing reference standards.

[0062] S54: Set the transmission ratio of the HMCVT to -0.7. At this time, only the mechanical power gear position 2 is engaged, and the transmission rotates in the forward direction. Check the pressure readings and status of each gear position to make them meet the current existing reference standards.

[0063] S55: Set the transmission ratio of the HMCVT to 0. After the transmission stops rotating, set the driving instruction to reverse, and then set the transmission ratio of the HMCVT to 0.1. At this time, only the hydraulic reverse gear position is engaged, and the transmission rotates in the reverse direction. Check the pressure readings and status of each gear position to make them meet the current existing reference standards.

[0064] S56: Set the transmission ratio of the HMCVT to 0.3. At this time, only the mechanical power reverse gear position is engaged, and the transmission rotates in the reverse direction. Check the pressure readings and status of each gear position to make them meet the current existing reference standards.

[0065] S6: Four-wheel drive function test

[0066] S61: Set the transmission ratio of the HMCVT to 0. After the transmission completely stops rotating, set the driving instruction to forward, and then set the transmission ratio of the HMCVT to -0.1 again. The front wheels rotate in the forward direction, and set the four-wheel drive instruction to engage. The installed hydraulic sensor monitors the oil circuit pressure, and check the pressure reading and the four-wheel drive gear position status at this time to make them meet the current existing reference standards. The pressure should be 0.

[0067] S62: Set the four-wheel drive instruction to disengage. Check the pressure readings and status of the four-wheel drive gear position at this time to make them meet the current existing reference standards.

[0068] S7: Differential lock function test

[0069] S71: Keep the driving instruction as forward, then set the transmission ratio of the HMCVT to -0.1, and set the differential lock instruction to engage. Check the differential lock status at this time to make them meet the current existing reference standards.

[0070] S72: Set the differential lock instruction to disengage again. Check the differential lock status at this time to make them meet the current existing reference standards.

[0071] S8: High and low gear function test

[0072] S81: Keep the driving instruction as forward, then set the HMCVT transmission ratio to 0, and finally set the high gear instruction. At this time, check the gear position, pressure, and status to make them meet the existing reference standards. The specific gear position needs to be confirmed by the value read by the position sensor; when the high gear instruction is issued and the position indication of the position sensor shows no change, it is necessary to confirm the polarity of the electromagnet, check whether the solenoid valve is leaking oil, and whether the mechanical body itself is stuck;

[0073] S82: Set the neutral gear instruction. At this time, check the gear position, pressure, and status to make them meet the existing reference standards;

[0074] S83: Set the low gear instruction. At this time, check the gear position, pressure, and status to make them meet the existing reference standards;

[0075] S9: PTO function test

[0076] S91: Set the transmission to neutral gear instruction, all gears of the transmission return to neutral, set the PTO gear to 540E, that is, gear 1, where E represents the economic mode, and 540 means that at a fixed input speed of the variable speed motor, the corresponding speed of the PTO gear is 540 r / min. Set the clutch instruction on the PTO to engaged. At this time, check the speed and status of the PTO output under this gear and this engagement instruction to make them meet the existing reference standards;

[0077] S92: Set the clutch instruction on the PTO to disengaged. Wait until the speed of the PTO output completely drops to 0, then set the PTO gear to 1000N, that is, gear 2, where N represents the normal mode. In order to reduce the phenomenon of gear clash during the gear shift of the synchronizer due to high speed, it takes 6 - 8 s for the speed to completely drop to 0 to prevent the clutch in the PTO from malfunctioning and causing the clutch in the PTO to not disengage. Then set the clutch instruction on the PTO to engaged. At this time, check the speed and status of the output under this gear and this engagement instruction to make them meet the existing reference standards;

[0078] S93: Set the clutch instruction on the PTO to disengaged. Wait until the speed of the PTO output completely drops to 0, then set the PTO gear to 1000E, that is, gear 3, and then set the clutch instruction on the PTO to engaged. At this time, check the speed and status of the output under this gear and this engagement instruction to make them meet the existing reference standards;

[0079] S10: Clutch pressure and current curve test

[0080] S101: Keep the oil temperature in the transmission hydraulic pump stable at 55 - 65 °C. If the temperature exceeds this range, perform water cooling; check the transmission to ensure it is in a fault-free state without error messages; set the input speed of the HMCVT to 1000 rpm; the operator manually sends relevant instructions to the controller and repeats S5 no less than 20 times, performing gear shuttles at different transmission ratios to fully flush the solenoid valve on the hydraulic pump and simultaneously remove the air bubbles in the solenoid valve cavity; then sequentially complete the following operations:

[0081] Since the HMCVT is in reverse at S56, sequentially set the transmission ratio of the HMCVT to 0 (to stop the HMCVT first), set the driving instruction to forward, set the parking instruction, set the high / low gear instruction to neutral, and set the driving instruction to neutral;

[0082] S102: The controller receives the instruction and sets the self-learning instruction for the first gear clutch, then the self-learning status starts to be displayed, with the statuses being self-learning start and self-learning end in sequence; during the entire process of running the self-learning instruction, the set current (i.e., the required current of the first gear clutch), the actual current, and the clutch pressure of the first gear clutch gradually increase synchronously; when the pressure of the first gear clutch reaches 4 - 5 bar, the rotational speed deviation of the first gear clutch is close to 0. If the deviation exceeds 10 rpm, the test of the pressure and current curve of the first gear clutch should be stopped, that is, the self-learning instruction is ended; after the test of the pressure and current curve of the first gear clutch is completed, view the corresponding curve of the pressure and the actual current. As the actual current gradually increases, ensure that the pressure of the first gear clutch increases linearly. When the actual current is 700 - 900 mA, the pressure tends to be stable, and there is no significant jump in the middle of the pressure value, that is, the pressure floating value does not exceed 0.5 bar;

[0083] S103: Repeat the test for the hydraulic gear clutch, the second gear clutch, and the reverse gear clutch, that is, repeat the process described in S102, but each gear has an independent operation instruction, which are the self-learning instruction for the hydraulic gear, the self-learning instruction for the second gear, and the self-learning instruction for the reverse gear, respectively. Ensure that the obtained pressure and actual current curves meet the reference standards. If it is found that they do not meet the standards, adjust the coil or replace the entire solenoid valve body;

[0084] S11: Rear axle brake clearance adjustment

[0085] S111: The subsequent self-learning needs to be carried out under braking conditions. Poor rear axle brake clearance will cause braking failure during self-learning, and the TCU will detect the relative vehicle speed, display a fault, and self-learning cannot be performed. First, set the parking instruction, drain the oil from the rear axle brake, and the ejector rod at the top of the rear axle brake housing descends. At this time, the top housing of the rear axle brake is in a loose state. The operator manually unscrews the top housing of the rear axle brake and uses a wrench to adjust the rear axle brake clearance counterclockwise to the maximum value.

[0086] S112: Release the parking brake command; then set the input speed of the HMCVT to 800 rpm, then set the driving command to reverse to supply oil to the rear axle brake, then set the high / low gear command to high gear, then set the HMCVT transmission ratio to 0.1, and finally set the differential lock command to engaged.

[0087] S113: The operator manually rotates the left rear axle brake adjusting lever clockwise. When the engine torque increases by 20 - 30 N.m on the original basis, it can be increased by 25 N.m during specific implementation. Then manually rotate the left rear axle brake adjusting lever counterclockwise, and rotate it counterclockwise and back 3 - 4 turns to ensure effective braking. 3.75 turns can be selected during specific operation.

[0088] S114: Set the differential lock command to disengaged. The operator manually rotates the right rear axle brake adjusting lever clockwise. When the engine torque increases by 20 - 30 N.m on the original basis, it can be increased by 25 N.m during specific implementation. Then manually rotate the right rear axle brake adjusting lever counterclockwise, and rotate it counterclockwise and back 3 - 4 turns to ensure effective braking. 3.75 turns can be selected during specific operation. Finally, screw on the rear axle brake housing.

[0089] S12: Oil pump efficiency test

[0090] When the oil temperature is 60°C, set the initial engine speed of the engine to 600 rpm, and then increase it in a gradient of 100 rpm. That is, after 600 rpm stabilizes, increase the speed to 700 rpm. After 700 rpm stabilizes, increase the speed to 800 rpm. In this way, keep increasing until 2000 rpm, and then decrease to 600 in the reverse order. Record the main oil circuit pressure, lubrication pressure, and the indication of the flow rate of the external pipeline of the gearbox at each stage. The unit of the flow rate indication is L / min. Calculate the oil pump efficiency according to the current formula to ensure that the oil pump efficiency is within the standard range;

[0091] S13: Self - learning test for both side A and side B of the volume speed - regulating circuit in the fixed - displacement motor - variable pump

[0092] S131: Keep the oil temperature in the gearbox hydraulic pump stable at 55 - 65°C. If the temperature exceeds this range, perform water cooling; check the gearbox to ensure it is in a fault - free state without error messages; set the input speed of the HMCVT to 1000 rpm; then complete the following operations in sequence: set the transmission ratio of the HMCVT to 0, set the driving command to forward, set the parking brake command, set the high / low gear command to neutral, and set the driving command to neutral;

[0093] S132: Set the self-learning instruction, and the self-learning status begins to be displayed, which is the start of self-learning of the volume speed control circuit side A in the fixed motor-variable pump, the self-learning of the volume speed control circuit side A in the fixed motor-variable pump, the end of self-learning of the volume speed control circuit side A in the fixed motor-variable pump, the start of self-learning of the volume speed control circuit side B in the fixed motor-variable pump, the self-learning of the volume speed control circuit side B in the fixed motor-variable pump, and the end of self-learning of the volume speed control circuit side B in the fixed motor-variable pump; after the self-learning process is completed, the self-learning instruction is released, different current values will produce different swing angles, and different swing angles will further produce different hydraulic displacements. Check the hydraulic displacement and current curves corresponding to different swing angles after self-learning to make them meet the reference standard;

[0094] S133: 11 different current values will be obtained in S132, so 11 different hydraulic displacement values and 11 different swing angle values will be generated accordingly, among which the first current value, the first hydraulic displacement value and the first swing angle value, as well as the last current value, the last hydraulic displacement value and the last swing angle value are all fixed values, and before the start of self-learning, there are 11 groups of fixed values, each group of values includes current value, hydraulic displacement value and swing angle value, so that the 9 changing swing angle values will form a threshold point, and the ratio of the absolute value of the hydraulic displacement value after learning at each threshold point to the corresponding fixed value and the absolute value of the absolute value must be less than 0.05, otherwise S132 is repeated for self-learning until the ratio of the absolute value of the hydraulic displacement value after learning to the corresponding fixed value and the absolute value of the absolute value is less than 0.05.

[0095] S14: Gear clutch self-learning test

[0096] S141: Keep the oil temperature in the gearbox hydraulic pump stable at 55-65°C. If it exceeds this temperature, water-cool it; check the gearbox to make sure it is in a fault-free state without any error message; set the input speed of the HMCVT to 1000rpm; then complete the following operations in sequence: set the transmission ratio of the HMCVT to 0, set the driving command to forward, set the parking command, set the high and low gear commands to neutral, and set the driving command to neutral;

[0097] S142: After the self-learning instruction is set, the self-learning status starts to be displayed, which is hydraulic gear start, hydraulic gear end, mechanical 1st gear start, mechanical 1st gear end, mechanical 2nd gear start, mechanical 2nd gear end, mechanical reverse gear start, mechanical reverse gear end; after the self-learning process is completed, the self-learning instruction is released, and the K point (professional term is KissPoint) current and corresponding pressure after the gear clutch self-learning are checked to make them meet the reference standard;

[0098] S143: When self-learning fails in a certain gear, the self-learning instruction will stop running and then report an error. At this time, the initial current value is adjusted, and the S142 step is repeated by increasing it by 10mA each time to complete the S142 test.

[0099] S15: PTO clutch self-learning test

[0100] S151: Keep the oil temperature in the gearbox hydraulic pump stable at 55-65℃. If it exceeds this temperature, water-cool it; check the gearbox to make sure it is in a fault-free state without any error information; set the input speed of HMCVT to 1000rpm; then complete the following operations in sequence: set the transmission ratio of HMCVT to 0, set the driving command to forward, set the parking command, set the high and low gear commands to neutral, set the driving command to neutral, and at the same time first set the PTO gear position to 1000N, and then set the clutch command on the PTO to engage. When the speed is detected to be stable, set the PTO clutch command to disconnect. At this time, the PTO1000 gear position is in gear;

[0101] S152: Set the self-learning instruction, and the self-learning status will start to be displayed, which is the start of PTO self-learning and the end of PTO self-learning. After the self-learning process is completed, the self-learning instruction is released, and the K point current and corresponding pressure after the PTO clutch self-learning are checked to make them meet the reference standard.

[0102] The above detection steps are relatively detailed, and the reference standard can be provided based on a large amount of original test data, which makes it very easy to detect faulty components or mechanical bodies.

[0103] S16: After all gear clutch self-learning, quantitative motor-variable pump volume speed control circuit A side and B side self-learning and PTO clutch self-learning tests are completed, the transmission controller is powered off uniformly. After the controller is completely powered off, it is powered on again to confirm that the data obtained from self-learning can be stored.

[0104] Table 1 Reference standard table

[0105]

[0106]

Claims

1. A bench-offline detection method for an automotive hydro-mechanical continuously variable transmission bridge, characterized in that, It includes the following steps: Step 1: Drive the speed of the transmission bridge to rise evenly. When the lubrication pressure, the main flow path pressure, and the pressures on both the A side and the B side of the displacement speed regulation circuit in the fixed-displacement motor-variable pump all gradually increase, conduct the shift function test, four-wheel drive function test, differential lock function test, and high-low gear function test in sequence; Step 2: Return all gears of the transmission bridge to neutral. First, make the clutch on the PTO in the engaged state in the 1st gear. When the speed and state of the PTO output meet the standards, then make the clutch on the PTO in the disengaged state. After the speed of the PTO output drops to 0, make the clutch on the PTO in the engaged state in the 2nd gear. When the speed and state of the PTO output meet the standards, make the clutch on the PTO in the disengaged state. After the speed of the PTO output drops to 0, make the clutch on the PTO in the engaged state in the 3rd gear. When the speed and state of the PTO output meet the standards, conduct the clutch pressure and current curve test; Step 3: First, make the transmission bridge in the parking state, then unscrew the rear axle brake housing, adjust the rear axle brake clearance counterclockwise to the maximum value, and then release the parking state of the transmission bridge. Set the input speed, set the reverse command, set the high gear command, set the transmission ratio to 0.1, and set the differential lock command to engaged for the transmission bridge in sequence. Then rotate the left rear axle brake adjusting rod clockwise. When the engine torque increases by 20 - 30 N·m, rotate the left rear axle brake adjusting rod counterclockwise for 3 - 4 turns. Immediately set the differential lock command to disengaged, rotate the right rear axle brake adjusting rod clockwise. When the engine torque increases by 20 - 30 N·m, rotate the right rear axle brake adjusting rod counterclockwise for 3 - 4 turns, screw on the rear axle brake housing, and finally conduct the oil pump efficiency test; Step 4: First, conduct the hydraulic displacement and current curve tests corresponding to different swing angles on both the A side and the B side of the displacement speed regulation circuit in the fixed-displacement motor-variable pump. When the K-point current and the corresponding pressure of the gear clutch meet the standards, determine whether the K-point current and the corresponding pressure of the PTO clutch meet the standards to complete the bench off-line inspection of the automotive hydro-mechanical continuously variable transmission bridge.

2. The bench off-line detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that The shift function test described in Step 1 is carried out according to the following process: Set the input speed for the transmission bridge. After there is no error message from the controller connected to the transmission bridge, set the transmission ratio of the transmission bridge to 0, set the parking release command, set the maximum torque value of the transmission bridge to 8000 N·m, and at the same time make the clutch signal not depressed. Then set the high gear command. After the pressures and states of all gears meet the standards, proceed to the subsequent steps; Set the transmission ratio of the transmission bridge to -0.

1. After the pressures and states of all gears meet the standards, proceed to the subsequent steps; Set the transmission ratio of the transmission bridge to -0.

3. After the pressures and states of all gears meet the standards, proceed to the subsequent steps; Set the transmission ratio of the transmission bridge to -0.

7. After the pressures and states of all gears meet the standards, proceed to the subsequent steps; Set the transmission ratio of the gearbox bridge to 0. After the gearbox bridge stops rotating, first set the reverse command, and then set the transmission ratio of the gearbox bridge to 0.

1. After the pressure and status of each gear meet the standards, proceed with the subsequent steps; Set the transmission ratio of the gearbox bridge to 0.3, and check whether the pressure and status of each gear meet the standards.

3. The bench off-line detection method of the automotive hydraulic mechanical continuously variable transmission bridge according to claim 1, characterized in that The four-wheel drive function test described in Step 1 is carried out as follows: Set the transmission ratio of the gearbox bridge to 0. After the gearbox bridge stops rotating, set the forward command, and then sequentially set the transmission ratio of the gearbox bridge to -0.1 and the four-wheel drive command to engaged. When the pressure indication and the four-wheel drive gear status meet the standards, set the four-wheel drive command to disengaged, and check whether the four-wheel drive gear pressure indication and status meet the standards.

4. The bench off-line detection method of the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that, The differential lock function test described in Step 1 is carried out as follows: Set the forward command for the gearbox bridge, and then sequentially set the transmission ratio of the gearbox bridge to -0.1 and the differential lock command to engaged. After the differential lock status meets the standards, set the differential lock command to disengaged, and check whether the differential lock status meets the standards.

5. The bench-offline detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that The high and low gear function test described in Step 1 is carried out as follows: Set the forward command for the gearbox bridge, and then sequentially set the transmission ratio of the gearbox bridge to 0 and the high gear command. When the gear position, pressure, and status meet the standards, issue the high gear command to the gearbox bridge. When the position indication of the position sensor changes, first set the neutral command for the gearbox bridge. When the gear position, pressure, and status meet the standards, then set the low gear command for the gearbox bridge, and check whether the gear position, pressure, and status meet the standards.

6. The bench off-line inspection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that The clutch pressure and current curve test described in Step 2 is carried out as follows: First, keep the oil temperature in the hydraulic pump at 55 - 65 °C. After the gearbox bridge has no faults, repeat the gear shifting function test process more than 20 times, and at the same time remove the air bubbles in the solenoid valve cavity. Then sequentially set the transmission ratio of the gearbox bridge to 0, set the forward command, set the parking command, set the high and low gear commands to neutral, and set the driving command to neutral. Finally, make the first gear clutch complete the following process: The first gear clutch obtains the self-learning start command, the first gear clutch runs the self-learning start command, and the set current, actual current, and pressure of the first gear clutch gradually increase synchronously. When the rotational speed deviation of the first gear clutch exceeds 10 rpm, the first gear clutch obtains the self-learning stop command, and the set current, actual current, and pressure of the first gear clutch no longer change. Judge whether the corresponding curve of the first gear clutch pressure and actual current meets the standards; The hydraulic gear clutch, the second gear clutch, and the reverse gear clutch are all tested according to the same process as the first gear clutch.

7. The bench off-line detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that, The oil pump efficiency test described in Step 3 is carried out as follows: When the oil temperature is 60°C, first drive the transmission bridge to rotate at a speed of 600 rpm, then drive the transmission bridge to rotate at a speed of 700 rpm, and then drive the transmission bridge to gradually rotate at a speed of 2000 rpm with a rising gradient of 100 rpm. Finally, lower the speed of the transmission bridge back to 600 rpm in the reverse process, record the main oil circuit pressure, lubrication pressure, and external pipeline flow rate readings corresponding to each speed point, and calculate whether the oil pump efficiency at each speed point is within the standard range using the main oil circuit pressure, lubrication pressure, and external pipeline flow rate readings corresponding to each speed point.

8. The bench-offline detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that Step 4 is carried out as follows to test the hydraulic displacement and current curves corresponding to different swing angles on both the A side and B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump: Step 4a: First, keep the oil temperature in the hydraulic pump at 55 - 65°C. After the transmission bridge has no faults, set the input speed for the transmission bridge. Then, sequentially set the transmission ratio of the transmission bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral. Step 4b: For the A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump, first obtain the self-learning start command. The A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump runs the self-learning start command, generating 9 different hydraulic displacement values and 9 different swing angle values. The A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning stop command and no longer generates hydraulic displacement values and swing angle values. Then, for the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump, obtain the self-learning start command. The B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump runs the self-learning start command, generating 9 different hydraulic displacement values and 9 different swing angle values. The B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump obtains the self-learning stop command and no longer generates hydraulic displacement values and swing angle values. Step 4c: Check whether the hydraulic displacement and current curves corresponding to different swing angles on the A side and B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump meet the reference standards. Step 4d, if the hydraulic displacement values P generated by the A side of the volume speed regulation circuit in the fixed-displacement motor-variable pump and the B side of the volume speed regulation circuit in the fixed-displacement motor-variable pump respectively i and the corresponding fixed value P k meet the following relationship, the hydraulic displacement and current curve test is qualified; otherwise, repeat Step 4b until the relationship is satisfied, and complete the test of the hydraulic displacement and current curve. |P i -P k | / P k <0.05。 9. The bench off-line detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that, Step 4 is carried out as follows to determine whether the K-point current and the corresponding pressure of the gear clutch meet the standards: Step 41: First, keep the oil temperature in the hydraulic pump at 55 - 65°C. After the transmission bridge has no faults, set the input speed for the transmission bridge. Then, sequentially set the transmission ratio of the transmission bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral. Step 42: The gear clutch obtains the self-learning start command, and the hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear perform self-learning in sequence. The hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear each generate different K-point currents and corresponding pressures, and respectively determine whether the K-point currents and corresponding pressures in the hydraulic gear, mechanical first gear, mechanical second gear, and mechanical reverse gear meet the standards.

10. The bench-offline detection method for the automotive hydro-mechanical continuously variable transmission bridge according to claim 1, characterized in that, Step 4 is carried out as follows to determine whether the K-point current and the corresponding pressure of the PTO clutch meet the standards: First, keep the oil temperature in the hydraulic pump at 55 - 65 °C. After the transmission bridge has no faults, set the input speed for the transmission bridge. Then, sequentially set the transmission ratio of the transmission bridge to 0, set the forward command, set the parking command, set the high / low gear command to neutral, and set the driving command to neutral. In the normal mode gear position, keep the clutch on the PTO engaged. When the speed output by the PTO is stable, disengage the clutch on the PTO. The PTO clutch receives the self - learning start command, generates different K - point currents and corresponding pressures. The PTO clutch receives the self - learning stop command, no longer generates K - point currents and pressures, and determines whether the K - point currents and corresponding pressures in the PTO clutch meet the standards.

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