A method for identifying cavitation in a torque converter and a data acquisition device

Abstract

The present invention belongs to the technical field of torque converters, and relates to a method for identifying cavitation of a hydrodynamic torque converter and a data acquisition device. The method of the present invention: adjust the input speed, output speed and outlet pressure of the torque converter, and obtain the inlet flow rate value and outlet flow rate value of the torque converter at different input speeds, output speeds and outlet pressures; calculate the cavitation occurrence threshold, and judge whether the torque converter has cavitation according to the cavitation occurrence threshold, inlet flow rate value and outlet flow rate value; record the minimum outlet pressure value when the torque converter does not have cavitation at different input speeds and output speeds, and obtain the lowest outlet back pressure according to the minimum outlet pressure value. The present invention can judge whether the hydrodynamic torque converter has cavitation according to the flow rate difference between the inlet and outlet of the hydrodynamic torque converter, and can obtain the minimum pressure value when the torque converter does not have cavitation under different working conditions, which is beneficial to ensuring the stability of the output performance of the hydrodynamic torque converter.

Description

Technical Field

[0001] The present invention belongs to the technical field of torque converters, and relates to a method for identifying cavitation of a hydraulic torque converter and a data acquisition device. Background Art

[0002] A hydraulic torque converter is a closed fluid mechanical device, mainly composed of a pump impeller, a turbine and a stator. Power from a power source such as an engine drives the rotation of the pump impeller to drive the hydraulic oil to move. Under the action of centrifugal force, the hydraulic oil passes through the turbine and the stator in sequence and then recirculates to the pump impeller to form a circulating liquid flow. The stator of the torque converter changes the direction of the circulating liquid flow from the turbine and redirects it to the pump impeller at a new angle, while providing the necessary torque reaction to achieve a continuous torque conversion function and having a flexible transmission function. Therefore, it is widely used in passenger cars, trucks, construction machinery and other transmission systems.

[0003] During the operation of the hydraulic torque converter, the flow state of the hydraulic oil in the torque converter cavity is very complex, with large pressure differences, temperature gradients and turbulent vortices in the flow field. Due to the increasing power density, a low-pressure vortex region is extremely likely to occur in the torque converter cavity, especially on the suction surface of the blades. When the pressure in the cavity is lower than a certain threshold, the gas dissolved in the oil is extremely likely to separate. When these bubbles flow with the liquid flow to the high-pressure region, the bubbles burst and dissolve, causing impact and vibration on the blade surface. The above is the cavitation phenomenon of the hydraulic torque converter. Cavitation will cause the flow state in the torque converter cavity to deteriorate, with gas-liquid two-phase substances existing. The impact of cavitation causes the surface of the metal structure of the torque converter impeller to peel off, the structure to be damaged, seriously affecting the service life of the hydraulic torque converter, and accompanied by vibration and noise.

[0004] A large number of studies have shown that the cavitation of the hydraulic torque converter and the system pressure are very significantly correlated. The external system pressure and the internal minimum pressure of the hydraulic torque converter show a positive correlation, that is, the higher the external pressure, the lower the possibility of cavitation of the hydraulic torque converter. If the system pressure fails to meet the requirements of the torque converter, it will cause cavitation of the hydraulic torque converter, a sharp decline in performance, a reduction in transmission efficiency, an increase in noise, and a significant shortening of the service life of key transmission components such as bearings, bushings, seals, one-way clutches, etc.

[0005] In the existing performance test methods of hydraulic torque converters, some test methods only conduct traction tests at low pump impeller input speeds. During the traction test at low pump impeller input speeds, the load of the hydraulic torque converter is small and cavitation is not likely to occur. Therefore, relatively ideal measurement results can often be obtained. However, during actual use, cavitation is likely to occur under large load conditions in the high pump impeller input speed and low speed ratio region, resulting in a serious decline in performance.

[0006] In the existing identification methods for cavitation in hydraulic torque converters, a cavitation identification method based on the noise of the sound pressure field is used for identification. For example, the paper titled Craig David Reynolds. Characterization Of Torque Converter Cavitation Sound Power Level Over Varying Speed Ratio [D]. Michigan Technological University, 2016; and the patent with the publication (announcement) number CN 115730241 A and the invention title of A Method for Constructing a Cavitation Noise Identification Model of a Hydraulic Turbine both require the additional introduction of noise measurement equipment and noise processing tools, resulting in high costs. Moreover, the discrimination of the sound pressure level is highly subjective and inaccurate.

[0007] In the existing performance test methods for hydraulic torque converters, the description of the system pressure definition is relatively vague. Generally, the pressure is defined based on experience, and the pressure value is a constant value. It is easy for the pressure value to be too high. Although the cavitation phenomenon of the hydraulic torque converter can be eliminated, a too high pressure value will cause a large loss in the oil supply system, resulting in unnecessary waste. Summary of the Invention

[0008] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a cavitation identification method and a data acquisition device for a hydraulic torque converter. The present invention can judge whether cavitation occurs in the hydraulic torque converter according to the flow difference between the inlet and outlet of the hydraulic torque converter, and can obtain the minimum pressure value when the torque converter does not cavitate under different working conditions, which is beneficial to ensuring the stability of the output performance of the hydraulic torque converter.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] The present invention discloses a cavitation identification method for a hydraulic torque converter, including the following steps:

[0011] Adjust the input speed, output speed, and outlet pressure of the torque converter to obtain the inlet flow value and outlet flow value of the torque converter at different input speeds, output speeds, and outlet pressures;

[0012] Calculate the cavitation occurrence threshold, and judge whether the torque converter cavitates according to the cavitation occurrence threshold, inlet flow value, and outlet flow value;

[0013] Record the minimum outlet pressure value when the torque converter does not cavitate at different input speeds and output speeds, and obtain the lowest outlet back pressure according to the minimum outlet pressure value.

[0014] Further, adjusting the input speed, output speed, and outlet pressure of the torque converter is specifically as follows:

[0015] Adjust the input speed of the torque converter and increase the output speed of the torque converter from 0 according to a fixed speed ratio;

[0016] After the output speed of the torque converter is adjusted once, adjust the outlet pressure of the torque converter after the output speed stabilizes;

[0017] Perform the next adjustment of the output speed until the output speed of the torque converter is the same as the input speed.

[0018] Furthermore, during the process of increasing the output speed of the torque converter from 0 according to a fixed speed ratio, the adjustment interval time between two adjacent output speed adjustments is at least 10 seconds;

[0019] The fixed speed ratio is 0:0.05:1.

[0020] Furthermore, the adjustment of the input speed of the torque converter is as follows:

[0021] After the input speed of the torque converter is adjusted once, make the next adjustment of the input speed after the output speed is the same as the input speed of the torque converter until the input speed of the torque converter reaches the maximum value.

[0022] Furthermore, the adjustment of the outlet pressure of the torque converter is as follows:

[0023] When the output speed of the torque converter is stable, adjust the outlet pressure of the torque converter, and judge whether cavitation occurs in the torque converter according to the cavitation occurrence threshold, the inlet flow value and the outlet flow value. If cavitation occurs, change the outlet pressure of the torque converter until cavitation does not occur in the torque converter.

[0024] Furthermore, the calculation of the cavitation occurrence threshold is as follows:

[0025] Obtain the inlet flow value and the outlet flow value of the torque converter when the input speed is equal to the output speed, and calculate the cavitation occurrence threshold according to the inlet flow value and the outlet flow value;

[0026] The calculation formula of the cavitation occurrence threshold is as follows:

[0027] ΔL = L in-let -L out-let

[0028] L cavitation = ΔL·δ

[0029] Wherein, ΔL is the difference between the inlet flow value and the outlet flow value when the input speed is equal to the output speed, L in-let is the inlet flow value when the input speed is equal to the output speed, L out-let is the outlet flow value when the input speed is equal to the output speed, L cavitation is the cavitation occurrence threshold, and δ is the cavitation resistance coefficient of the hydraulic torque converter.

[0030] Further, it is determined whether cavitation occurs in the torque converter according to the cavitation occurrence threshold, the inlet flow rate value, and the outlet flow rate value as follows:

[0031] Calculate the flow rate difference based on the inlet flow rate value and the outlet flow rate value. If the flow rate difference is less than or equal to the cavitation occurrence threshold, it is determined that cavitation occurs; otherwise, cavitation does not occur.

[0032] The formula for obtaining the lowest outlet back pressure according to the outlet pressure value is as follows:

[0033]

[0034] Wherein, P i_n_random is the lowest outlet back pressure, P i_ni is the outlet pressure value of the torque converter when cavitation does not occur, and a, b, and c are all fitting coefficients.

[0035] In addition, the present invention also discloses a device for obtaining cavitation identification data of a hydraulic torque converter, including a torque converter. The input end of the torque converter is connected to the output end of a drive motor module, the output end of the torque converter is connected to a load motor module, the torque converter is respectively connected to a hydraulic oil circulation pump module and a hydraulic oil cooling module, and the hydraulic oil circulation pump module is connected to the hydraulic oil cooling module;

[0036] The input end of the torque converter is connected to an input speed sensor, and the output end of the torque converter is connected to an output speed sensor;

[0037] Between the hydraulic oil circulation pump module and the torque converter, it is connected to an input flow rate sensor and an input pressure sensor, and between the hydraulic oil cooling module and the torque converter, it is connected to an output pressure sensor and an output flow rate sensor;

[0038] The output pressure sensor, the output flow rate sensor, the output speed sensor, the input speed sensor, the input flow rate sensor, and the input pressure sensor are all connected to a data acquisition unit;

[0039] The data acquisition unit, the hydraulic oil circulation pump module, the hydraulic oil cooling module, the load motor module, and the drive motor module are all connected to a control module.

[0040] Further, between the hydraulic oil circulation pump module and the torque converter, it is connected to an input temperature sensor, and between the hydraulic oil cooling module and the torque converter, it is connected to an output temperature sensor;

[0041] The input end of the torque converter is connected to an input torque sensor, and the output end of the torque converter is connected to an output torque sensor;

[0042] The output temperature sensor, the input torque sensor, the output torque sensor, and the input temperature sensor are all connected to the data acquisition unit.

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

[0044] 1. By adjusting the input speed, output speed and outlet pressure of the torque converter, the method of the present invention enables the torque converter to operate under different working conditions, so as to obtain the inlet flow rate value and outlet flow rate value of the torque converter at different input speeds, output speeds and outlet pressures.

[0045] 2. By calculating the cavitation occurrence threshold and judging whether cavitation occurs in the torque converter according to the cavitation occurrence threshold, inlet flow rate value and outlet flow rate value, compared with the prior art's cavitation identification method based on the noise of the sound pressure field, there is no need to additionally introduce noise measurement equipment and noise processing tools, and the cavitation identification accuracy is strong. Record the minimum outlet pressure value when cavitation does not occur in the torque converter at different input speeds and output speeds, and obtain the lowest outlet back pressure according to the minimum outlet pressure value. By measuring the output speed of the full-speed range speed ratio under different input speed conditions, the lowest system outlet pressure value required by the measured torque converter under different input speeds and output speeds is identified. Compared with the constant pressure value given based on experience values, while ensuring the stability of the output performance of the hydraulic torque converter, the present invention can reduce the risk of cavitation of high-power hydraulic torque converters. The present invention can judge whether cavitation occurs in the hydraulic torque converter according to the inlet and outlet flow rate difference of the hydraulic torque converter, and can obtain the minimum pressure value when cavitation does not occur under different working conditions of the torque converter, which is beneficial to ensuring the stability of the output performance of the hydraulic torque converter.

[0046] 3. The device of the present invention can flexibly change the working conditions of the torque converter, accurately obtain the relevant data information of the input speed, output speed, outlet pressure, inlet flow rate value and outlet flow rate value of the torque converter under different working conditions, so as to assist in completing the cavitation identification of the hydraulic torque converter and accurately find the pressure value of the torque converter under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the method flow chart of the present invention;

[0048] Figure 2 is the structure diagram of the data acquisition device of the present invention;

[0049] Figure 3 is the traction test flow chart of the present invention;

[0050] Figure 4 is the cavitation determination flow chart of the present invention.

[0051] Figure 5 is the curve graph of the lowest system pressure allowed at each pump impeller input speed of the present invention

[0052] Wherein: 1. Control module; 2. Data acquisition unit; 3. Hydraulic oil circulation pump module; 4. Hydraulic oil cooling module; 5. Output pressure sensor; 6. Output temperature sensor; 7. Output flow rate sensor; 8. Load motor module; 9. Output rotation speed sensor; 10. Output torque sensor; 11. Torque converter; 11a. Input end of the torque converter; 11b. Output end of the torque converter; 12. Input torque sensor; 13. Input rotation speed sensor; 14. Driving motor module; 15. Input flow rate sensor; 16. Input temperature sensor; 17. Input pressure sensor; 18. Input oil circuit; 19. Output oil circuit. Detailed implementation manners

[0053] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0055] The present invention will be further described in detail below in conjunction with the accompanying drawings:

[0056] See Figure 1 , the present invention discloses a method for identifying cavitation of a torque converter, comprising the following steps:

[0057] S1. Adjust the input rotation speed, output rotation speed and outlet pressure of the torque converter 11, and obtain the inlet flow rate value and outlet flow rate value of the torque converter 11 at different input rotation speeds, output rotation speeds and outlet pressures;

[0058] Preferably, adjusting the input rotation speed, output rotation speed and outlet pressure of the torque converter 11 is specifically as follows:

[0059] Adjust the input speed of the torque converter 11, and increase the output speed of the torque converter 11 from 0 according to a fixed speed ratio;

[0060] After the output speed of the torque converter 11 is adjusted once, adjust the outlet pressure of the torque converter 11 after the output speed stabilizes;

[0061] Make the next adjustment of the output speed until the output speed of the torque converter 11 is the same as the input speed.

[0062] Preferably, during the process of increasing the output speed of the torque converter 11 from 0 according to a fixed speed ratio, the adjustment interval time between two adjacent output speed adjustments is at least 10 seconds;

[0063] The fixed speed ratio is 0:0.05:1.

[0064] Preferably, the adjustment of the input speed of the torque converter 11 is as follows:

[0065] After the input speed of the torque converter 11 is adjusted once, make the next adjustment of the input speed after the output speed is the same as the input speed of the torque converter 11 until the input speed of the torque converter 11 reaches the maximum value.

[0066] Preferably, the adjustment of the outlet pressure of the torque converter 11 is as follows:

[0067] When the output speed of the torque converter 11 is stable, adjust the outlet pressure of the torque converter 11, and judge whether the torque converter 11 has cavitation according to the cavitation occurrence threshold, the inlet flow value and the outlet flow value. If cavitation occurs, change the outlet pressure of the torque converter 11 until the torque converter 11 does not have cavitation.

[0068] Preferably, the change of the outlet pressure of the torque converter 11 is as follows:

[0069] Increase the outlet pressure of the torque converter 11 successively by a fixed difference.

[0070] S2. Calculate the cavitation occurrence threshold, and judge whether the torque converter 11 has cavitation according to the cavitation occurrence threshold, the inlet flow value and the outlet flow value;

[0071] Preferably, the calculation of the cavitation occurrence threshold is as follows:

[0072] Obtain the inlet flow value and the outlet flow value of the torque converter 11 when the input speed is equal to the output speed, and calculate the cavitation occurrence threshold according to the inlet flow value and the outlet flow value.

[0073] Preferably, the calculation formula of the cavitation occurrence threshold is as follows:

[0074] ΔL = L in-let -L out-let

[0075] L cavitation = ΔL·δ

[0076] Wherein, ΔL is the difference between the inlet flow rate value and the outlet flow rate value when the input rotational speed is equal to the output rotational speed, L in-let is the inlet flow rate value when the input rotational speed is equal to the output rotational speed, L out-let is the outlet flow rate value when the input rotational speed is equal to the output rotational speed, L cavitation is the cavitation occurrence threshold, and δ is the cavitation resistance coefficient of the torque converter.

[0077] Preferably, it is determined whether the torque converter 11 has cavitation according to the cavitation occurrence threshold, the inlet flow rate value and the outlet flow rate value as follows:

[0078] Calculate the flow rate difference according to the inlet flow rate value and the outlet flow rate value. If the flow rate difference is less than or equal to the cavitation occurrence threshold, it is determined that cavitation has occurred; otherwise, cavitation has not occurred.

[0079] S3. Record the minimum outlet pressure value of the torque converter 11 when no cavitation occurs at different input rotational speeds and output rotational speeds, and obtain the lowest outlet back pressure according to the minimum outlet pressure value.

[0080] Preferably, the formula for obtaining the lowest outlet back pressure according to the minimum outlet pressure value is as follows:

[0081]

[0082] Wherein, P i_n_random is the lowest outlet back pressure, P i_ni is the outlet pressure value of the torque converter 11 when no cavitation occurs, and a, b, and c are all fitting coefficients.

[0083] See Figure 1In another feasible embodiment of the present invention, the following is adaptively modified according to the situation. The input speed, output speed and outlet pressure of the torque converter 11 are adjusted to make the torque converter 11 work in different working conditions, so as to obtain the inlet flow value and outlet flow value of the torque converter 11 at different input speeds, output speeds and outlet pressures. The cavitation threshold is calculated, and whether the torque converter 11 has cavitation occurs is determined according to the cavitation threshold, the inlet flow value and the outlet flow value. Compared with the cavitation identification method based on the acoustic pressure field noise in the prior art, no additional noise measurement equipment and noise processing tools are required, and the cavitation identification accuracy is high. The minimum outlet pressure value of the torque converter 11 when no cavitation occurs at different input speeds and output speeds is recorded, and the minimum outlet back pressure is obtained according to the minimum outlet pressure value. By measuring the output speed of the full-speed speed ratio under different input speed conditions, the minimum system outlet pressure value required by the torque converter under different input speed and output speed conditions is identified. Compared with the constant pressure value given based on the empirical value, the present invention can reduce the risk of cavitation of a high-power torque converter while ensuring the stability of the output performance of the torque converter. For a system with adjustable oil supply pressure, the pressure can be set according to different pump wheel input speed conditions to achieve precise pressure control and reduce the energy loss of the oil supply system as much as possible. The present invention can determine whether cavitation occurs in the torque converter according to the inlet and outlet flow difference of the torque converter, and can obtain the minimum pressure value of the torque converter 11 without cavitation under different working conditions, which is conducive to ensuring the stability of the output performance of the torque converter.

[0084] Embodiment 1:

[0085] See also Figure 1 and Figure 3 This embodiment discloses a method for identifying cavitation in a torque converter, which is mainly implemented by the following technical solutions:

[0086] The speed control mode is adopted to control the driving motor module 14 and the load motor module 8 to rotate at the same speed and in the same direction, and the input and output of the torque converter 11 are kept rotating at the same speed, and the speed is the minimum input speed n allowed by the torque converter 11. in_min , through the control module 1 and the hydraulic oil circulation pump module 3, the outlet pressure of the torque converter 11 is set to the minimum pressure P0 that the device of the present invention can provide;

[0087] In the speed control mode, by adjusting the rotation speed of the load motor module 8, the output shaft speed of the torque converter 11 is reduced to 0 r / min or close to 0 r / min according to a certain slope, and maintained for more than 10 seconds, and then the output shaft speed of the torque converter 11 is increased according to the speed ratio of 0:0.02:1, and each speed ratio is maintained for more than 10 seconds until the output shaft speed is the same as the input shaft speed;

[0088] Preferably, the data is collected for more than 10 seconds under each test condition;

[0089] After the data collection is completed, the data is transmitted to the data acquisition unit 2, processed by the control module 1, and the cavitation determination process is started to determine whether cavitation occurs under the test speed condition;

[0090] If no cavitation phenomenon occurs in each speed ratio condition, record the outlet pressure of the torque converter 11 at this time as P0;

[0091] If cavitation occurs in all speed ratio conditions or some speed ratio conditions, the outlet pressure P0 of the torque converter 11 is increased in sequence according to the increment of Δp through the control module 1 and the hydraulic oil circulation pump module 3, and the above test is repeated until the cavitation phenomenon disappears; record the outlet pressure P at this time i_n＝min ;

[0092] Adopt the speed control mode, and increase the input speed of the torque converter by adjusting the rotation speed of the drive motor module 14 according to a certain speed increment Δn until the maximum designed input speed n of the torque converter 11 is reached in_max , repeat the above test to find the lowest allowable outlet pressure P at different speeds i_ni ;

[0093] When calculating the lowest allowable outlet back pressure P under each random input speed n i_n_random , the lowest outlet pressure P at other speeds i_n_random is calculated by performing a quadratic function fitting. i_ni Among them, P

[0094]

[0095] is the lowest outlet back pressure, P i_n_random is the outlet pressure value of the torque converter 11 when no cavitation occurs, and a, b, and c are all fitting coefficients. i_ni

[0096] Figure 4 Further, referring to Figure 4 The method for identifying cavitation of the hydraulic torque converter of the present invention is specifically as follows:

[0097] Keep the input and output speeds of the torque converter 11 rotating at the same speed, and record the inlet flow rate L of the torque converter in-let and the outlet flow rate L out-let ;

[0098] Calculate the test flow rate difference ΔL = L in-let -L out-let when the input and output speeds of the torque converter rotate at the same speed, and calculate the cavitation occurrence threshold L cavitation=ΔL·δ, where δ is the torque converter anti-cavitation coefficient, which is obtained based on torque converter measurement;

[0099] During the traction test of the torque converter 11, the torque converter inlet and outlet flow difference ΔL is recorded under any speed ratio condition. i ;

[0100] If ΔL i ≤L cavitation , it is determined that cavitation occurs, otherwise cavitation does not occur;

[0101] The determination process ends.

[0102] Where ΔL is the difference between the inlet flow rate and the outlet flow rate when the input speed is equal to the output speed, L in-let is the inlet flow value when the input speed is equal to the output speed, L out-let is the outlet flow value when the input speed is equal to the output speed, L cavitation is the cavitation threshold, and δ is the anti-cavitation coefficient of the torque converter.

[0103] Compared with the prior art, the present invention has the following advantages:

[0104] The present invention compares the test flow difference ΔL with the judgment value L set by the system. cavitation To determine whether cavitation occurs, compared with the existing cavitation identification method based on acoustic pressure field noise, it does not require the introduction of additional noise measurement equipment and noise processing tools, and the cavitation identification accuracy is high.

[0105] The present invention also provides a method for calibrating and identifying the cavitation pressure of a hydraulic torque converter, by measuring a constant speed traction test of a full speed range speed ratio under different pump input speed conditions, to identify the minimum system pressure P required by the torque converter 11 under different pump input speed conditions. i_ni Compared with the constant pressure value given based on experience, it can reduce the risk of cavitation of high-power torque converters while ensuring the stability of torque converter output performance. For systems with adjustable oil supply pressure, the pressure can be set according to different pump input speed conditions to achieve precise pressure control and minimize the energy loss of the oil supply system.

[0106] Embodiment 2:

[0107] See also Figure 1 and Figure 3 This embodiment discloses a method for identifying cavitation of a torque converter, which mainly determines whether the current system pressure setting is appropriate by identifying whether cavitation occurs, and specifically includes the following steps:

[0108] Step S101, turn on the power of the test bench and check whether the bench is normal;

[0109] Step S102, adopt the speed control mode to control the rotation speed and rotation direction of the drive motor module 14 and the load motor module 8. Through the control module 1, set the input rotation speed of the drive motor module 14 to the lowest input rotation speed n allowed by the torque converter 11 in_min , in this solution, it is set to 600 r / min, and set the input rotation speed of the drive motor module 14;

[0110] Step S103, through the control module 1, adjust the rotation speed of the load motor module 8 to keep the input and output rotation speeds of the torque converter 11 rotating at the same speed and in the same direction;

[0111] Step S104, through the control module 1 and the hydraulic oil circulation pump module 3, adjust the outlet pressure P0 of the torque converter 11. In the initial state, the outlet pressure P0 of the torque converter 11 is set to 0.05 MPa, and the adjustment increment value Δp of the outlet pressure is 0.1 MPa;

[0112] Step S105, adopt the speed control mode. By adjusting the rotation speed of the load motor module 8, reduce the output shaft rotation speed to 0 r / min or close to 0 r / min at a certain slope, and maintain it for a period of time, preferably 10 seconds. Then, increase the rotation speed of the output shaft according to the rotation speed ratio matrix of 0:0.05:1, and maintain it for a period of time at each rotation speed ratio, preferably 10 seconds, until the output shaft rotation speed and the input shaft rotation speed are the same.

[0113] Preferably, the single working condition data acquisition time is 10 seconds;

[0114] Step S106, after the data acquisition is completed, each sensor transmits the data to the data acquisition unit 2. Through the control module 1, process the data to determine whether cavitation occurs under the test rotation speed working condition. If cavitation occurs in any speed ratio working condition or all working conditions in 0:0.05:1, then enter Step S107. On the contrary, if no cavitation phenomenon occurs during the process of increasing the rotation speed of the output shaft, enter Step S108.

[0115] Step S107, increase the outlet pressure P0 of the torque converter according to the increment of Δp, Δp is 0.1 MPa, and then enter Step S104;

[0116] Step S108, record the outlet pressure P at this time i_n＝min ;

[0117] Step S109, determine whether the input rotation speed of the current drive motor module 14 is the highest input rotation speed n allowed by the torque converter 11 in_max , in this implementation scheme, it is 1800 r / min. If it is, then enter Step S111. If not, then enter Step S110;

[0118] Step S110, increase the set value of the input speed of the torque converter by a certain speed increment Δn. In this implementation, the speed increment Δn is set to 100 r / min, and enter step S102. Record the lowest outlet pressure P corresponding to different input speeds n of the pump impeller in sequence. i-in corresponding to i_ni ;

[0119] Step S111, the test ends;

[0120] Furthermore, referring to Figure 5 , when calculating the lowest allowable outlet back pressure P at each random input speed n, the lowest outlet pressure P at other speeds is calculated by performing a quadratic function fitting. i_n_random at i_n_random Furthermore, referring to i-in , the cavitation determination process is as follows:

[0121]

[0122] Furthermore, referring to Figure 4 , the cavitation determination process is as follows:

[0123] Step S601, start the determination process;

[0124] Step S602, set the input speed of the drive motor module 14;

[0125] Step S603, keep the input and output speeds of the torque converter rotating at the same speed;

[0126] Step S604, record the inlet flow rate L in-let and the outlet flow rate L out-let ;

[0127] Step S605, calculate the test flow rate difference when the input and output speeds of the torque converter rotate at the same speed

[0128] ΔL = L in-let - L out-let

[0129] Step S606, calculate the cavitation occurrence threshold L cavitation = ΔL·δ, where δ is the cavitation resistance coefficient of the hydraulic torque converter, which is obtained according to the measurement of the torque converter;

[0130] Step S607, during the traction test of the torque converter 11, record the inlet and outlet flow rate difference ΔL of the torque converter under any speed ratio condition i . If ΔL i ≤L cavitation , it is determined that cavitation occurs, and enter step S608. Otherwise, enter step S609;

[0131] Step S608, output a cavitation occurrence signal;

[0132] Step S609, output a signal indicating no cavitation occurred;

[0133] Step S610, determine the end of the process.

[0134] See Figure 2 , the present invention also discloses a device for obtaining cavitation identification data of a torque converter, including a torque converter 11. The input end 11a of the torque converter 11 is connected to the output end of a driving motor module 14, and the output end 11b of the torque converter 11 is connected to a load motor module 8. The driving motor module 14 is used to adjust the input speed of the torque converter 11, and the load motor module 8 is used to adjust the output speed of the torque converter 11.

[0135] The torque converter 11 is respectively connected to a hydraulic oil circulation pump module 3 and a hydraulic oil cooling module 4. The hydraulic oil circulation pump module 3 is connected to the hydraulic oil cooling module 4. The hydraulic oil circulation pump module 3 and the hydraulic oil cooling module 4 are used to continuously circulate and provide cooling hydraulic oil for the torque converter 11.

[0136] The input end 11a of the torque converter is connected to an input speed sensor 13, and the output end 11b of the torque converter is connected to an output speed sensor 9. The input speed sensor 13 is used to obtain the input speed of the torque converter 11, and the output speed sensor 9 is used to obtain the output speed of the torque converter 11.

[0137] Between the hydraulic oil circulation pump module 3 and the torque converter 11, it is connected to an input flow rate sensor 15 and an input pressure sensor 17. Between the hydraulic oil cooling module 4 and the torque converter 11, it is connected to an output pressure sensor 5 and an output flow rate sensor 7. The input flow rate sensor 15 is used to obtain the input flow rate of the hydraulic oil of the torque converter 11, the input pressure sensor 17 is used to obtain the input pressure of the hydraulic oil of the torque converter 11, the output pressure sensor 5 is used to obtain the output pressure of the hydraulic oil of the torque converter 11, and the output flow rate sensor 7 is used to obtain the output flow rate of the hydraulic oil of the torque converter 11.

[0138] The output pressure sensor 5, the output flow rate sensor 7, the output speed sensor 9, the input speed sensor 13, the input flow rate sensor 15, and the input pressure sensor 17 are all connected to a data acquisition unit 2. The data acquisition unit 2 is used for data acquisition of each sensor and transmits the data to a control module 1.

[0139] The data acquisition unit 2, the hydraulic oil circulation pump module 3, the hydraulic oil cooling module 4, the load motor module 8, and the driving motor module 14 are all connected to the control module 1. The control module 1 is used to process the data transmitted by the data acquisition unit 2 and regulate the hydraulic oil circulation pump module 3, the hydraulic oil cooling module 4, the load motor module 8, and the driving motor module 14 to achieve adjustment of the input speed, output speed, and outlet pressure of the torque converter 11.

[0140] The device of the present invention can flexibly change the working conditions of the torque converter 11, accurately obtain the relevant data information of the input speed, output speed, outlet pressure, inlet flow rate value and outlet flow rate value of the torque converter 11 under different working conditions, so as to assist in completing the cavitation identification of the hydraulic torque converter and accurately find the pressure values of the torque converter 11 under different working conditions.

[0141] Preferably, an input temperature sensor 16 is connected between the hydraulic oil circulation pump module 3 and the torque converter 11, and an output temperature sensor 6 is connected between the hydraulic oil cooling module 4 and the torque converter 11;

[0142] The input end 11a of the torque converter is connected to an input torque sensor 12, and the output end 11b of the torque converter is connected to an output torque sensor 10;

[0143] The output temperature sensor 6, the input torque sensor 12, the output torque sensor 10 and the input temperature sensor 16 are all connected to the data acquisition unit 2.

[0144] Embodiment Three:

[0145] See Figure 2 , this embodiment discloses a device for obtaining data for cavitation identification of a hydraulic torque converter, including a control module 1; 2, a data acquisition unit 2; 3, a hydraulic oil circulation pump module 3; 4, a hydraulic oil cooling module 4; 5, an output pressure sensor 5; 6, an output temperature sensor 6; 7, an output flow rate sensor 7; 8, a load motor module 8; 9, an output speed sensor 9; 10, an output torque sensor 10; 11, a torque converter 11; 11a, the input end 11a of the torque converter; 11b, the output end 11b of the torque converter; 12, an input torque sensor 12; 13, an input speed sensor 13; 14, a driving motor module 14; 15, an input flow rate sensor 15; 16, an input temperature sensor 16; 17, an input pressure sensor 17; 18, an input oil circuit 18; 19, an output oil circuit 19;

[0146] The driving motor module 14 is rigidly connected to the input end 11a of the torque converter, and can directly drive the torque converter 11 to rotate forward and backward, or apply a load torque to the input end;

[0147] The load motor module 8 is rigidly connected to the output end 11b of the torque converter, and can directly drive the torque converter 11 to rotate forward and backward, or apply a load torque to the output end;

[0148] The input torque sensor 12 is arranged at the input end 11a of the torque converter, and the output torque sensor 10 is arranged at the output end 11b of the torque converter, and is used for collecting the torque values of the input end and the output end and transmitting the collected values to the data acquisition unit 2;

[0149] The input speed sensor 13 and the output speed sensor 9 are arranged at the input end 11a and the output end 11b of the torque converter 11, and are used to collect the torque values of the input end 11a and the output end 11b, and transmit the collected values to the data acquisition unit 2;

[0150] The input temperature sensor 16 is arranged in the hydraulic oil input oil circuit 18 of the torque converter, and the output temperature sensor 6 is arranged in the hydraulic oil output oil circuit 19 of the torque converter, and is used to collect the oil temperature values of the input oil circuit 18 and the output oil circuit 19, and transmit the collected values to the data acquisition unit 2;

[0151] The input pressure sensor 17 and the output pressure sensor 5 are arranged at the ports of the hydraulic oil input oil circuit 18 and the output oil circuit 19 of the torque converter 11, and are used to collect the pressure values at the ports of the input oil circuit 18 and the output oil circuit 19, and transmit the collected values to the data acquisition unit 2;

[0152] The hydraulic oil circulation pump module 3 and the hydraulic oil cooling module 4, the hydraulic oil circulation pump module 3 is connected to the torque converter 11 and the hydraulic oil cooling module 4, pumps the high-temperature hydraulic oil flowing out of the torque converter 11 into the hydraulic oil cooling module 4 for filtration and cooling, and then pumps it into the torque converter 11 to form a hydraulic oil circulation, specifically as follows:

[0153] The oil output end of the torque converter 11 is connected to the input end of the hydraulic cooling module 4, and the oil flowing out of the oil output end of the torque converter 11 enters the hydraulic oil cooling module 4 through the output oil circuit 19 and is cooled;

[0154] The input end of the hydraulic oil circulation pump module 3 is connected to the output end of the hydraulic oil cooling module 4, the cooled hydraulic oil enters the hydraulic oil circulation pump module 3, and after being pressurized by the hydraulic oil circulation pump module 3, it enters the torque converter 11 through the input oil circuit 18;

[0155] The data acquisition unit 2 is connected to the control module 1, and the data acquisition unit 2 transmits the collected data to the control module 1 in real time;

[0156] The control module 1 is connected to the drive motor module 14, the load motor module 8, the hydraulic oil circulation pump module 3 and the hydraulic oil cooling module 4, and controls the signal processing such as the start, operation, stop, and alarm of the entire bench test equipment, as well as the control of the oil temperature and oil pressure at the outlet of the torque converter 11.

[0157] The input flow rate sensor 15 and the output flow rate sensor 7 are arranged in the hydraulic oil input oil circuit 18 and the output oil circuit 19 of the torque converter 11, and are used to collect the flow rate values of the input oil circuit 18 and the output oil circuit 19, and transmit the collected values to the data acquisition unit 2;

[0158] The input temperature sensor 16 is arranged in the hydraulic oil input oil circuit 18 of the torque converter, and the output temperature sensor 6 is arranged in the hydraulic oil output oil circuit 19 of the torque converter, and is used for collecting the oil temperature values of the input oil circuit 18 and the output oil circuit 19 and transmitting the collected values to the data acquisition unit 2;

[0159] The input pressure sensor 17 and the output pressure sensor 5 are arranged at the ports of the hydraulic oil input oil circuit 18 and the output oil circuit 19 of the torque converter 11, and are used for collecting the pressure values at the ports of the input oil circuit 18 and the output oil circuit 19 and transmitting the collected values to the data acquisition unit 2;

[0160] The present invention judges whether cavitation occurs in the torque converter according to the flow difference between the inlet and outlet of the torque converter, and then tests the minimum inlet and outlet pressure conditions required by the torque converter under various rotational speed conditions, so as to avoid large distortion of the test results caused by cavitation during the basic performance test of the torque converter.

[0161] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for identifying cavitation in a torque converter, characterized in that: The following steps are involved: Adjusting the input speed, output speed and outlet pressure of the torque converter (11) to obtain inlet flow rate values ​​and outlet flow rate values ​​of the torque converter (11) at different input speeds, output speeds and outlet pressures; Calculating a cavitation occurrence threshold, and judging whether cavitation occurs in the torque converter (11) according to the cavitation occurrence threshold, an inlet flow value, and an outlet flow value; The minimum outlet pressure value of the torque converter (11) when no cavitation occurs at different input speeds and output speeds is recorded, and the minimum outlet back pressure is obtained according to the minimum outlet pressure value.

2. The method for identifying cavitation of a torque converter according to claim 1, characterized in that: The input speed, output speed and outlet pressure of the torque converter (11) are adjusted as follows: Adjusting the input speed of the torque converter (11) and increasing the output speed of the torque converter (11) from 0 according to a fixed speed ratio; After the output speed of the torque converter (11) is adjusted once, the outlet pressure of the torque converter (11) is adjusted after the output speed is stabilized; The next output speed adjustment is performed until the output speed of the torque converter (11) is the same as the input speed.

3. The method for identifying cavitation of a torque converter according to claim 2, characterized in that: In the process of increasing the output speed of the torque converter (11) from 0 according to the fixed speed ratio, the interval between two adjacent output speed adjustments is at least 10 seconds; The fixed speed ratio is 0:0.05:

1.

4. The method for identifying cavitation of a torque converter according to claim 2, characterized in that: The input speed of the torque converter (11) is adjusted as follows: After the input speed of the torque converter (11) is adjusted once, the next input speed adjustment is performed after the output speed is the same as the input speed of the torque converter (11), until the input speed of the torque converter (11) reaches a maximum value.

5. The method for identifying cavitation of a torque converter according to claim 2, characterized in that: The outlet pressure of the torque converter (11) is adjusted as follows: When the output speed of the torque converter (11) is stabilized, the outlet pressure of the torque converter (11) is adjusted, and it is determined whether cavitation occurs in the torque converter (11) based on the cavitation occurrence threshold, the inlet flow value, and the outlet flow value. If cavitation occurs, the outlet pressure of the torque converter (11) is changed until cavitation does not occur in the torque converter (11).

6. A method for identifying cavitation in a torque converter according to claim 1 or 5, characterized in that: The calculation of the cavitation occurrence threshold is as follows: Obtaining an inlet flow rate value and an outlet flow rate value of the torque converter (11) when the input speed is equal to the output speed, and calculating a cavitation occurrence threshold value according to the inlet flow rate value and the outlet flow rate value; The calculation formula for the cavitation occurrence threshold is as follows: ΔL=L in-let -L out-let L cavitation =ΔL·δ Where ΔL is the difference between the inlet flow rate and the outlet flow rate when the input speed is equal to the output speed, L in-let is the inlet flow value when the input speed is equal to the output speed, L out-let is the outlet flow value when the input speed is equal to the output speed, L cavitation is the cavitation threshold, and δ is the anti-cavitation coefficient of the torque converter.

7. A method for identifying cavitation in a torque converter according to claim 1 or 5, characterized in that: The method of judging whether cavitation occurs in the torque converter (11) according to the cavitation occurrence threshold, the inlet flow value and the outlet flow value is specifically as follows: The flow difference is calculated based on the inlet flow value and the outlet flow value. If the flow difference is less than or equal to the cavitation occurrence threshold, it is determined that cavitation occurs, otherwise cavitation does not occur.

8. The method for identifying cavitation of a torque converter according to claim 1, characterized in that: The formula for obtaining the minimum outlet back pressure according to the minimum outlet pressure value is as follows: Among them, P i_n_random is the minimum outlet back pressure, P i_ni is the outlet pressure value of the torque converter (11) when no cavitation occurs, and a, b and c are all fitting coefficients.

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