Cam shaft durability test method, equipment and medium

Abstract

The invention discloses a durability test method and device for a camshaft and a medium, relates to the technical field of durability tests, and solves the problem that the durability test of the camshaft in different practical application states cannot be carried out, and the method comprises the steps: collecting the initial parameters of the camshaft used by a plug-in hybrid drive automobile; the method comprises the following steps: placing a camshaft in a camshaft test bed, carrying out a cyclic wear test on the camshaft, carrying out characteristic data acquisition on the camshaft subjected to the cyclic wear test, and carrying out a pressure test on a shaft body and a cam peach tip at a cam mounting position of the camshaft under a specific temperature condition; according to the results of the cyclic wear test and the pressure test, the durability of the camshaft is comprehensively analyzed. The durability test of the camshaft in different actual application states is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of durability testing, and in particular relates to a camshaft durability testing method, equipment and medium. Background Art

[0002] The camshaft is a component in a piston engine that controls the opening and closing of the valves. Although the camshaft's speed is half that of the crankshaft in a four-stroke engine, it is usually still very high and needs to withstand a large torque. Therefore, the design of the camshaft requires high strength and support. Its material is generally high-quality alloy steel or alloy steel. Since the valve movement is related to the power and operating characteristics of an engine, the camshaft design occupies a very important position in the engine design process. In the prior art, camshafts lack durability testing under different actual application conditions, such as the camshaft's operating conditions during cold start, normal operation, and overload operation, as well as the pressure resistance of the camshaft shaft and cam lobe under high temperature. To this end, the present invention provides a camshaft durability test method, equipment and medium. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention aims to provide a camshaft durability test method, equipment and medium.

[0004] The technical problems to be solved by the present invention are: How to implement durability testing of camshafts under different actual application conditions.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a camshaft durability test method includes: Step S1, collecting initial parameters of a camshaft used in a plug-in hybrid vehicle; Step S2, placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft; Step S3, collecting characteristic data of the camshaft after the cyclic wear test; Step S4, performing a pressure test on the shaft body and the cam lobe at the camshaft where the cam is mounted under specific temperature conditions; Step S5: Comprehensively analyzing the durability of the camshaft based on the results of the cyclic wear test and the pressure test.

[0006] Furthermore, the collection process in step S1 includes: Step S11, dividing the camshaft into a cam and a shaft body where the cam is mounted; Step S12: record the arc end of the cam as the cam base circle, place the cam in a plane rectangular coordinate system, and obtain the coordinates (Xai, Yai) of each point on the cam base circle, where i = 1, 2, ..., n, where n is a positive integer and i is the number of each point on the base circle; Step S13, calculating the initial center coordinates (Xc, Yc) of the cam base circle and the initial radius Rjy of the cam base circle by the least square method; Step S131, summing up the abscissas of the points on the cam base circle, taking the average value, and then multiplying the sum by 2 to obtain the initial abscissa Xc of the center of the cam base circle; Similarly, add the ordinates of each point on the cam base circle, take the average value, and multiply by 2 to obtain the initial ordinate Yc of the center of the cam base circle. Step S132, by formula The initial radius Rjy of the cam base circle is calculated.

[0007] Furthermore, the collection process in step S1 further includes: Step S14, by formula Calculate the actual distance rsj from each point on the cam base circle to the center of the cam base circle; Step S15, subtracting the radius of the cam base circle from the actual distance from each point on the cam base circle to the center of the cam base circle to obtain the radial deviation of each point on the cam base circle; Step S16, traversing and comparing the radial deviations of all points on the cam base circle to obtain the maximum and minimum values ​​of the radial deviations, and subtracting the minimum value of the radial deviation from the maximum value of the radial deviation at each point on the cam base circle to obtain the initial roundness error of the cam base circle; Step S17: Obtain the coordinates of each point on the corresponding cam profile, traverse and compare the ordinates of each point on the cam profile in the first quadrant and the second quadrant to obtain the maximum ordinate value, record the point corresponding to the maximum ordinate value as the cam lobe, obtain the horizontal and vertical coordinates of the cam lobe and record them as the initial lobe coordinates (Xt1, Yt1) of the cam lobe; Step S18: Measure the outer diameter of the camshaft where the cam is installed and record it as the initial outer diameter of the camshaft.

[0008] Furthermore, the test process in step S2 includes the following sub-steps: Step S21, connecting one end of the camshaft to the rotating module, installing the other end of the camshaft in a fixing device, installing a test base under the camshaft, and aligning each cam on the camshaft with the metal block; Step S22, setting a first speed, a second speed, and a third speed for the rotation module; wherein the speed of the first speed is lower than the speed of the second speed, and the speed of the second speed is lower than the speed of the third speed; Step S23, performing a cyclic wear test on the camshaft; Step S24: Repeat the cyclic wear test on the camshaft for a fixed number of times.

[0009] Furthermore, the test process of the cyclic wear test in step S23 is specifically as follows: Step S231, adjusting the rotation speed of the rotating module to a first rotation speed, so that the camshaft operates at the first rotation speed for a first fixed time period; Step S232: After the camshaft maintains the first speed for a first fixed time, spraying engine oil onto the surface of the camshaft. Simultaneously, adjusting the speed of the rotating module to a second speed so that the camshaft continues to operate at the second speed for a second fixed time. Step S233: After the camshaft maintains the second speed for a second fixed time, spraying engine oil onto the surface of the camshaft, and adjusting the speed of the rotating module to a third speed so that the camshaft continues to operate at the third speed for a third fixed time. Step S234, after the camshaft maintains the third speed and operates for a third fixed time, the oil on the surface of the camshaft is cleaned and the test is stopped; The first fixed duration is shorter than the second fixed duration and the third fixed duration, and the second fixed duration is longer than the third fixed duration. Step S235, record steps S231 to S234 as a cyclic wear test.

[0010] Furthermore, the feature data collection process in step S3 is as follows: Step S31, obtain the actual lobe coordinates (Xt2, Yt2) of the cam lobe after the cyclic wear test, and use the formula Calculate the wear distance JL of the cam lobe in the camshaft; Step S32, comparing the wear distance of the cam lobe in the camshaft with a wear distance threshold; If the wear distance of the cam lobe in the camshaft is greater than or equal to the wear distance threshold, the corresponding camshaft will be marked as a product with unqualified durability; If the wear distance of the cam lobe in the camshaft is less than the wear distance threshold, proceed to the next step; Step S33, obtaining the coordinates (Xbi, Ybi) of each point on the cam base circle after the cyclic wear test, and repeating step S13 to calculate the actual center coordinates of the cam base circle center and the actual radius of the cam base circle after the cyclic wear test by the least squares method; Step S34, repeating steps S14 to S16 to calculate the actual roundness error of the cam base circle after the cyclic wear test; Step S35, subtracting the initial roundness error from the actual roundness error and taking the absolute value to obtain the roundness variation of the cam base circle; Step S36, collecting the outer diameter of the camshaft where the cam is mounted after the cyclic wear test and recording it as the actual outer diameter of the camshaft; Step S37: Subtract the initial shaft outer diameter from the actual shaft outer diameter and take the absolute value to obtain the outer diameter wear of the shaft at the camshaft mounting cam.

[0011] Furthermore, the pressure test process in step S4 includes the following sub-steps: Step S41, obtaining historical operating temperatures of camshafts of the same type, traversing and comparing the historical operating temperatures of all camshafts of the same type to obtain a maximum value of the historical operating temperatures, and recording the maximum value of the historical operating temperatures of the camshafts of the same type as the test temperature; Step S42: Fixing the camshaft shaft at the cam mounting location in a ring test device, preheating the camshaft shaft at the cam mounting location to a test temperature, and gradually increasing the pressure of the ring test device until the camshaft shaft breaks, and recording the corresponding pressure at the time of fracture as the shaft yield pressure; Step S43: Measure the distance from the cam lobe to the lowest point of the cam base circle and record it as the cam length. Fix the cam base circle portion in a fixture, preheat the cam lobe to the test temperature, and periodically apply pressure to the cam lobe until the cam length changes. Record the pressure at the corresponding moment as the cam deformation pressure of the cam lobe.

[0012] Furthermore, the analysis process in step S5 includes the following sub-steps: Step S51, comparing the shaft yield pressure at the camshaft where the cam is mounted with the shaft yield pressure threshold, and comparing the cam deformation pressure at the cam lobe with the cam deformation pressure threshold; Step S52: If the shaft yield pressure at the camshaft where the cam is mounted is less than the shaft yield pressure threshold or the cam deformation pressure at the cam lobe is less than the cam deformation pressure threshold, the corresponding camshaft is marked as a product with unqualified durability. Step S53: If the shaft yield pressure at the camshaft where the cam is mounted is greater than or equal to the shaft yield pressure threshold and the cam deformation pressure of the cam lobe is greater than or equal to the cam deformation pressure threshold, proceed to the next step; Step S54, comparing the roundness variation of the cam base circle with the standard roundness variation, and comparing the outer diameter wear of the camshaft at the cam mounting position with the outer diameter wear standard; Step S55: If the roundness variation of the cam base circle is less than the standard roundness variation and the outer diameter wear of the camshaft body at the cam mounting position is less than the outer diameter wear standard, the corresponding camshaft is marked as a product with qualified durability; If the roundness change of the cam base circle is greater than or equal to the standard roundness change or the outer diameter wear of the shaft body at the cam installation point is greater than or equal to the standard outer diameter wear, the corresponding camshaft will be recorded as a product with unqualified durability.

[0013] According to a second aspect, an electronic device is provided, characterized in that the electronic device comprises: a memory storing a computer program; The processor is in communication with the memory, and when the computer program is executed by the processor, the durability test method of the camshaft is implemented.

[0014] In a third aspect, a computer-readable storage medium stores a computer program thereon, wherein the program implements the camshaft durability test method when executed by a processor.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention first collects initial parameters of the camshaft used in a plug-in hybrid vehicle, then places the camshaft in a camshaft test bench and performs a cyclic wear test on the camshaft. Subsequently, characteristic data is collected from the camshaft after the cyclic wear test. This invention effectively analyzes the wear state of the camshaft at different speeds. 2. The present invention also performs a pressure test on the shaft body and cam lobe tip at the camshaft where the cam is installed under specific temperature conditions, and at the same time conducts a comprehensive analysis of the durability of the camshaft based on the results of the cyclic wear test and the pressure test. The present invention realizes the durability test of the camshaft under different actual application conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0017] Figure 1 is a flow chart of the method of the present invention; Figure 2 is a schematic diagram of the camshaft of the present invention; Figure 3 is a schematic diagram of the cam in the present invention; Figure 4 Schematic diagram of the cyclic wear test device of the present invention; Figure 5 is a schematic diagram of the annular pressure device of the present invention; Figure 6 It is a structural schematic diagram of the electronic device in the present invention. DETAILED DESCRIPTION

[0018] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] Example 1: Please refer to Figure 1-Figure 5 As shown, the technical solution provided by the present invention is: a camshaft durability test method, the method is as follows: In this embodiment, a plurality of camshafts are selected from the same batch of camshafts used in plug-in hybrid vehicles for durability testing. The selected camshafts are divided into two groups, one for cyclic wear testing and the other for pressure testing. Step S1, collecting initial parameters of a camshaft used in a plug-in hybrid vehicle; In this embodiment, the acquisition process in step S1 is as follows: Step S11, please refer to Figure 2 As shown, the camshaft is divided into a cam, a camshaft shaft body, and a shaft body where the camshaft is mounted; Step S12, see Figure 3 As shown, the arc end of the cam is recorded as the cam base circle, the cam is placed in a plane rectangular coordinate system, and the coordinates (Xai, Yai) of each point on the cam base circle are obtained, i = 1, 2, ..., n, n is a positive integer, and i is the number of each point on the base circle; Step S13, calculating the initial center coordinates (Xc, Yc) of the cam base circle and the initial radius Rjy of the cam base circle by the least square method; The calculation process of the initial center coordinates of the cam base circle center and the initial radius of the cam base circle in step S13 is as follows: Step S131, summing up the abscissas of the points on the cam base circle, taking the average value, and then multiplying the sum by 2 to obtain the initial abscissa Xc of the center of the cam base circle; Similarly, add the ordinates of each point on the cam base circle, take the average value, and multiply by 2 to obtain the initial ordinate Yc of the center of the cam base circle. Step S132, by formula Calculate the initial radius Rjy of the cam base circle; Step S14, by formula Calculate the actual distance rsj from each point on the cam base circle to the center of the cam base circle; Step S15, subtracting the radius of the cam base circle from the actual distance from each point on the cam base circle to the center of the cam base circle to obtain the radial deviation of each point on the cam base circle; Step S16, traversing and comparing the radial deviations of all points on the cam base circle to obtain the maximum and minimum values ​​of the radial deviations, and subtracting the minimum value of the radial deviation from the maximum value of the radial deviation at each point on the cam base circle to obtain the initial roundness error of the cam base circle; Step S17: Obtain the coordinates of each point on the corresponding cam profile, traverse and compare the ordinates of each point on the cam profile in the first quadrant and the second quadrant to obtain the maximum ordinate value, record the point corresponding to the maximum ordinate value as the cam lobe, obtain the horizontal and vertical coordinates of the cam lobe and record them as the initial lobe coordinates (Xt1, Yt1) of the cam lobe; Step S18: Measure the outer diameter of the camshaft where the cam is installed and record it as the initial outer diameter of the camshaft.

[0020] Step S2, placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft; Furthermore, the test process in step S2 includes the following sub-steps: Step S21, please refer to Figure 4 As shown, connect one end of the camshaft to the rotating module, install the other end of the camshaft in the fixture, install the test base under the camshaft, and ensure that each cam on the camshaft is aligned with the metal block; In this embodiment, the camshaft test bench is used to simulate the actual working state of the camshaft opening or closing the valve in the engine. The camshaft test bench includes a rotating module and a test base. The rotating module can actually be a rotating motor. The fixing device can be a fixture that fixes the camshaft. There are fixing springs on the test base, and each spring is fixed with a metal block. In this embodiment, the elastic coefficient of the spring is set to be the same as the elastic coefficient of the spring in actual camshaft application. Step S22, setting a first speed, a second speed, and a third speed for the rotation module; wherein the speed of the first speed is lower than the speed of the second speed, and the speed of the second speed is lower than the speed of the third speed; Step S23, performing a cyclic wear test on the camshaft; The specific test process of the cyclic wear test in step S23 is as follows: Step S231, adjusting the rotation speed of the rotating module to a first rotation speed, so that the camshaft operates at the first rotation speed for a first fixed time period; Step S232: After the camshaft maintains the first speed for a first fixed time, spraying engine oil onto the surface of the camshaft. Simultaneously, adjusting the speed of the rotating module to a second speed so that the camshaft continues to operate at the second speed for a second fixed time. Step S233: After the camshaft maintains the second speed for a second fixed time, spraying engine oil onto the surface of the camshaft, and adjusting the speed of the rotating module to a third speed so that the camshaft continues to operate at the third speed for a third fixed time. Step S234, after the camshaft maintains the third speed and operates for a third fixed time, the oil on the surface of the camshaft is cleaned and the test is stopped; The first fixed duration is shorter than the second fixed duration and the third fixed duration, and the second fixed duration is longer than the third fixed duration. In this embodiment, the camshaft is operated at the first speed to simulate the wear of the camshaft during a cold start of the engine. The camshaft is operated at the second speed to simulate the wear of the camshaft during normal engine operation. Since this stage is normal operation, the second fixed time is the longest. The camshaft is operated at the third speed to simulate the wear of the camshaft during overload operation of the engine. For example, in this embodiment, the first speed may be 1000 rpm, the first fixed time may be 1 hour, the second speed may be 2000 rpm, the second fixed time may be 5 hours, the third speed may be 3500 rpm, and the third fixed time may be 2 hours; Step S235, recording steps S231 to S234 as a cyclic wear test; Step S24, repeatedly performing a fixed number of cyclic wear tests on the camshaft; For example, the camshaft is subjected to a fixed number of 30 repetitions of the cyclic wear test.

[0021] Step S3, collecting characteristic data of the camshaft after the cyclic wear test; In this embodiment, the process of collecting the characteristic data in step S3 is as follows: Step S31, obtain the actual lobe coordinates (Xt2, Yt2) of the cam lobe after the cyclic wear test, and use the formula Calculate the wear distance JL of the cam lobe in the camshaft; Step S32, comparing the wear distance of the cam lobe in the camshaft with a wear distance threshold; If the wear distance of the cam lobe in the camshaft is greater than or equal to the wear distance threshold, the corresponding camshaft will be marked as a product with unqualified durability; If the wear distance of the cam lobe in the camshaft is less than the wear distance threshold, proceed to the next step; Step S33, obtaining the coordinates (Xbi, Ybi) of each point on the cam base circle after the cyclic wear test, and repeating step S13 to calculate the actual center coordinates of the cam base circle center and the actual radius of the cam base circle after the cyclic wear test by the least squares method; Step S34, repeating steps S14 to S16 to calculate the actual roundness error of the cam base circle after the cyclic wear test; Step S35, subtracting the initial roundness error from the actual roundness error and taking the absolute value to obtain the roundness variation of the cam base circle; Step S36, collecting the outer diameter of the camshaft where the cam is installed after the cyclic wear test and recording it as the actual outer diameter of the camshaft; Step S37, subtracting the initial shaft outer diameter from the actual shaft outer diameter and taking the absolute value to obtain the outer diameter wear of the shaft at the camshaft mounting cam.

[0022] Step S4, performing a pressure test on the shaft body and the cam lobe at the camshaft where the cam is mounted under specific temperature conditions; In this embodiment, the pressure test process in step S4 includes the following sub-steps: Step S41, obtaining historical operating temperatures of camshafts of the same type, traversing and comparing the historical operating temperatures of all camshafts of the same type to obtain a maximum value of the historical operating temperatures, and recording the maximum value of the historical operating temperatures of the camshafts of the same type as the test temperature; Step S42, see Figure 5 As shown, the shaft body of the camshaft at which the cam is mounted is fixed in a ring test device, the shaft body at which the cam is mounted is preheated to the test temperature, the pressure of the ring test device is gradually increased until the shaft body of the camshaft breaks, and the pressure corresponding to the break is recorded as the shaft body yield pressure; In this embodiment, the ring test device is a ring-shaped pressure device, and the inner ring of the ring test device is sleeved onto the shaft body where the cam is installed; Step S43: Measure the distance from the cam lobe to the lowest point of the cam base circle and record it as the cam length. Fix the cam base circle portion in a fixture, preheat the cam lobe to the test temperature, and use a pressure device to periodically apply pressure to the cam lobe until the cam length changes. The pressure at the corresponding moment is recorded as the cam deformation pressure of the cam lobe. It should be explained that the use of the pressure device to periodically apply pressure to the cam lobe tip is as follows: every time pressure is applied to the cam lobe tip for 1 minute, the application of pressure is stopped for 10 seconds; In this embodiment, the shaft body and the cam lobe at the camshaft where the cam is mounted are preheated to the test temperature in order to simulate and test the pressure resistance of the shaft body and the cam lobe under extreme operating temperatures.

[0023] Step S5, performing a comprehensive analysis on the durability of the camshaft based on the results of the cyclic wear test and the pressure test; In this embodiment, the analysis process in step S5 includes the following sub-steps: Step S51, comparing the shaft yield pressure at the camshaft where the cam is mounted with the shaft yield pressure threshold, and comparing the cam deformation pressure at the cam lobe with the cam deformation pressure threshold; Step S52: If the shaft yield pressure at the camshaft where the cam is mounted is less than the shaft yield pressure threshold or the cam deformation pressure at the cam lobe is less than the cam deformation pressure threshold, the corresponding camshaft is marked as a product with unqualified durability. Step S53: If the shaft yield pressure at the camshaft where the cam is mounted is greater than or equal to the shaft yield pressure threshold and the cam deformation pressure of the cam lobe is greater than or equal to the cam deformation pressure threshold, proceed to the next step; Step S54, comparing the roundness variation of the cam base circle with the standard roundness variation, and comparing the outer diameter wear of the camshaft at the cam mounting position with the outer diameter wear standard; Step S55: If the roundness variation of the cam base circle is less than the standard roundness variation and the outer diameter wear of the camshaft body at the cam mounting position is less than the outer diameter wear standard, the corresponding camshaft is marked as a product with qualified durability; If the roundness change of the cam base circle is greater than or equal to the standard roundness change or the outer diameter wear of the shaft body at the cam installation point is greater than or equal to the standard outer diameter wear, the corresponding camshaft will be recorded as a product with unqualified durability.

[0024] In this application, if a corresponding calculation formula appears, the above calculation formula is dimensionless and its numerical calculation is performed. The weight coefficient, proportional coefficient and other coefficients in the formula are set to a result value obtained by quantifying each parameter. Regarding the size of the weight coefficient and the proportional coefficient, as long as it does not affect the proportional relationship between the parameter and the result value, it is acceptable.

[0025] Example 2: Figure 6 This is a schematic diagram of the structure of an electronic device, which may include: a processor, a communications interface, memory, and a communications bus. The processor, communications interface, and memory communicate with each other via the communications bus. The processor can call logic instructions in the memory to execute a camshaft durability testing method. The method includes: collecting initial parameters of a camshaft used in a plug-in hybrid vehicle; placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft; collecting characteristic data of the camshaft after the cyclic wear test; performing a pressure test on the camshaft body and cam lobe at the cam mounting point under specific temperature conditions; and conducting a comprehensive analysis of the camshaft durability based on the results of the cyclic wear and pressure tests.

[0026] In addition, the logical instructions in the above-mentioned memory can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the existing technology, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0027] On the other hand, the present application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can perform a camshaft durability test method provided by the above methods, the method including: collecting initial parameters of a camshaft used in a plug-in hybrid vehicle, placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft, collecting characteristic data of the camshaft after the cyclic wear test, performing a pressure test on the shaft body and cam lobe at the cam mounting location of the camshaft under specific temperature conditions, and performing a comprehensive analysis of the durability of the camshaft based on the results of the cyclic wear test and the pressure test.

[0028] On the other hand, the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the above-mentioned camshaft durability test method, the method comprising: collecting initial parameters of a camshaft used in a plug-in hybrid vehicle, placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft, collecting characteristic data of the camshaft after the cyclic wear test, performing a pressure test on the shaft body and cam lobe at the cam mounting location of the camshaft under specific temperature conditions, and conducting a comprehensive analysis of the durability of the camshaft based on the results of the cyclic wear test and the pressure test.

[0029] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0030] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A camshaft durability test method, characterized in that: include: Step S1, collecting initial parameters of a camshaft used in a plug-in hybrid vehicle; Step S2, placing the camshaft in a camshaft test bench and performing a cyclic wear test on the camshaft; Step S3, collecting characteristic data of the camshaft after the cyclic wear test; Step S4, performing a pressure test on the shaft body and the cam lobe at the camshaft where the cam is mounted under specific temperature conditions; Step S5: Comprehensively analyzing the durability of the camshaft based on the results of the cyclic wear test and the pressure test.

2. A camshaft durability test method according to claim 1, characterized in that: The acquisition process in step S1 includes: Step S11, dividing the camshaft into a cam and a shaft body where the cam is mounted; Step S12: record the arc end of the cam as the cam base circle, place the cam in a plane rectangular coordinate system, and obtain the coordinates (Xai, Yai) of each point on the cam base circle, where i = 1, 2, ..., n, where n is a positive integer and i is the number of each point on the base circle; Step S13, calculating the initial center coordinates (Xc, Yc) of the cam base circle and the initial radius Rjy of the cam base circle by the least square method; Step S131, summing up the abscissas of the points on the cam base circle, taking the average value, and then multiplying the sum by 2 to obtain the initial abscissa Xc of the center of the cam base circle; Similarly, add the ordinates of each point on the cam base circle, take the average value, and multiply by 2 to obtain the initial ordinate Yc of the center of the cam base circle. Step S132, by formula The initial radius Rjy of the cam base circle is calculated.

3. The camshaft durability test method according to claim 2, characterized in that: The acquisition process in step S1 further includes: Step S14, by formula Calculate the actual distance rsj from each point on the cam base circle to the center of the cam base circle; Step S15, subtracting the radius of the cam base circle from the actual distance from each point on the cam base circle to the center of the cam base circle to obtain the radial deviation of each point on the cam base circle; Step S16, traversing and comparing the radial deviations of all points on the cam base circle to obtain the maximum and minimum values ​​of the radial deviations, and subtracting the minimum value of the radial deviation from the maximum value of the radial deviation at each point on the cam base circle to obtain the initial roundness error of the cam base circle; Step S17: Obtain the coordinates of each point on the corresponding cam profile, traverse and compare the ordinates of each point on the cam profile in the first quadrant and the second quadrant to obtain the maximum ordinate value, record the point corresponding to the maximum ordinate value as the cam lobe, obtain the horizontal and vertical coordinates of the cam lobe and record them as the initial lobe coordinates (Xt1, Yt1) of the cam lobe; Step S18: Measure the outer diameter of the camshaft where the cam is installed and record it as the initial outer diameter of the camshaft.

4. A camshaft durability test method according to claim 3, characterized in that: The test process in step S2 includes the following sub-steps: Step S21, connecting one end of the camshaft to the rotating module, installing the other end of the camshaft in a fixing device, installing a test base under the camshaft, and aligning each cam on the camshaft with the metal block; Step S22, setting a first speed, a second speed, and a third speed for the rotation module; wherein the speed of the first speed is lower than the speed of the second speed, and the speed of the second speed is lower than the speed of the third speed; Step S23, performing a cyclic wear test on the camshaft; Step S24: Repeat the cyclic wear test on the camshaft for a fixed number of times.

5. The camshaft durability test method according to claim 4, characterized in that: The specific test process of the cyclic wear test in step S23 is as follows: Step S231, adjusting the rotation speed of the rotating module to a first rotation speed, so that the camshaft operates at the first rotation speed for a first fixed time period; Step S232: After the camshaft maintains the first speed for a first fixed time, spraying engine oil onto the surface of the camshaft. Simultaneously, adjusting the speed of the rotating module to a second speed so that the camshaft continues to operate at the second speed for a second fixed time. Step S233: After the camshaft maintains the second speed for a second fixed time, spraying engine oil onto the surface of the camshaft, and adjusting the speed of the rotating module to a third speed so that the camshaft continues to operate at the third speed for a third fixed time. Step S234, after the camshaft maintains the third speed and operates for a third fixed time, the oil on the surface of the camshaft is cleaned and the test is stopped; The first fixed duration is shorter than the second fixed duration and the third fixed duration, and the second fixed duration is longer than the third fixed duration. Step S235, record steps S231 to S234 as a cyclic wear test.

6. A camshaft durability test method according to claim 5, characterized in that: The process of collecting the characteristic data in step S3 is as follows: Step S31, obtain the actual lobe coordinates (Xt2, Yt2) of the cam lobe after the cyclic wear test, and use the formula Calculate the wear distance JL of the cam lobe in the camshaft; Step S32, comparing the wear distance of the cam lobe in the camshaft with a wear distance threshold; If the wear distance of the cam lobe in the camshaft is greater than or equal to the wear distance threshold, the corresponding camshaft will be marked as a product with unqualified durability; If the wear distance of the cam lobe in the camshaft is less than the wear distance threshold, proceed to the next step; Step S33, obtaining the coordinates (Xbi, Ybi) of each point on the cam base circle after the cyclic wear test, and repeating step S13 to calculate the actual center coordinates of the cam base circle center and the actual radius of the cam base circle after the cyclic wear test by the least squares method; Step S34, repeating steps S14 to S16 to calculate the actual roundness error of the cam base circle after the cyclic wear test; Step S35, subtracting the initial roundness error from the actual roundness error and taking the absolute value to obtain the roundness variation of the cam base circle; Step S36, collecting the outer diameter of the camshaft where the cam is mounted after the cyclic wear test and recording it as the actual outer diameter of the camshaft; Step S37: Subtract the initial shaft outer diameter from the actual shaft outer diameter and take the absolute value to obtain the outer diameter wear of the shaft at the camshaft mounting cam.

7. A camshaft durability test method according to claim 6, characterized in that: The pressure test process in step S4 includes the following sub-steps: Step S41, obtaining historical operating temperatures of camshafts of the same type, traversing and comparing the historical operating temperatures of all camshafts of the same type to obtain a maximum value of the historical operating temperatures, and recording the maximum value of the historical operating temperatures of the camshafts of the same type as the test temperature; Step S42: Fixing the camshaft shaft at the cam mounting location in a ring test device, preheating the camshaft shaft at the cam mounting location to a test temperature, and gradually increasing the pressure of the ring test device until the camshaft shaft breaks, and recording the corresponding pressure at the time of fracture as the shaft yield pressure; Step S43: Measure the distance from the cam lobe to the lowest point of the cam base circle and record it as the cam length. Fix the cam base circle portion in a fixture, preheat the cam lobe to the test temperature, and periodically apply pressure to the cam lobe until the cam length changes. Record the pressure at the corresponding moment as the cam deformation pressure of the cam lobe.

8. The camshaft durability test method according to claim 7, characterized in that: The analysis process in step S5 includes the following sub-steps: Step S51, comparing the shaft yield pressure at the camshaft where the cam is mounted with the shaft yield pressure threshold, and comparing the cam deformation pressure at the cam lobe with the cam deformation pressure threshold; Step S52: If the shaft yield pressure at the camshaft where the cam is mounted is less than the shaft yield pressure threshold or the cam deformation pressure at the cam lobe is less than the cam deformation pressure threshold, the corresponding camshaft is marked as a product with unqualified durability. Step S53: If the shaft yield pressure at the camshaft where the cam is mounted is greater than or equal to the shaft yield pressure threshold and the cam deformation pressure of the cam lobe is greater than or equal to the cam deformation pressure threshold, proceed to the next step; Step S54, comparing the roundness variation of the cam base circle with the standard roundness variation, and comparing the outer diameter wear of the camshaft at the cam mounting position with the outer diameter wear standard; Step S55: If the roundness variation of the cam base circle is less than the standard roundness variation and the outer diameter wear of the camshaft body at the cam mounting position is less than the outer diameter wear standard, the corresponding camshaft is marked as a product with qualified durability; If the roundness change of the cam base circle is greater than or equal to the standard roundness change or the outer diameter wear of the shaft body at the cam installation point is greater than or equal to the standard outer diameter wear, the corresponding camshaft will be recorded as a product with unqualified durability.

9. An electronic device, characterized in that: The electronic device comprises: a memory storing a computer program; A processor is communicatively connected to the memory, and when the computer program is executed by the processor, the method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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