Transfer case right-angle reversing test device, test system and test method

Abstract

The invention provides a transfer case right-angle reversing test device, test system and test method, and belongs to the technical field of automobile transmission system tests.The transfer case right-angle reversing test device comprises a shell, a reversing transmission mechanism and a speed ratio adjusting mechanism are arranged in the shell, and the reversing transmission mechanism comprises a middle shaft, an output shaft and an input shaft; an input gear is fixed to the input shaft, and the two ends of the telescopic transmission shaft are connected with the input shaft and the output end of an external driving mechanism through universal joints respectively. The intermediate shaft is sleeved with a first intermediate shaft gear and a second intermediate shaft gear, and a first output gear and a second output gear are fixed to the output shaft. The input gear is constantly meshed with the first intermediate shaft gear, the first intermediate shaft gear is constantly meshed with the first output gear to form a first transmission path, and the second intermediate shaft gear is constantly meshed with the second output gear to form a second transmission path. The problem that in the prior art, one test bench can only adapt to transfer cases of a single type or specification is solved.

Description

Technical Field

[0001] This invention relates to the field of automotive transmission system testing technology, and in particular to a transfer case right-angle commutation test device, test system and test method. Background Technology

[0002] The transfer case is a key component of the four-wheel drive vehicle's transmission system, responsible for distributing power to the front and rear axles. Its performance directly affects the vehicle's power, reliability, and safety. During the research and development and production phases, indoor bench tests are required to simulate actual working conditions to verify core indicators such as transmission efficiency and fatigue life, ensuring that it meets the vehicle's requirements.

[0003] Chinese invention patent CN105547693A discloses a test bench for loading and testing a four-wheel drive vehicle transfer case. The bench includes a T-slot cast iron platform, a drive AC motor, a gearbox, a transfer case under test, and two load DC motors mounted on it. The drive AC motor is connected to the gearbox input via an electromagnetic clutch, and the gearbox output is connected to the transfer case input via a torque sensor. The front and rear output shafts of the transfer case are respectively connected to the two load DC motors to simulate the load on the entire vehicle.

[0004] However, both dedicated test benches and whole-vehicle testing suffer from a limitation in existing technologies: a single test bench can only accommodate a single type or specification of transfer case. Because different transfer case models vary significantly in structural dimensions, interface locations, transmission ratios, and torque capacity, existing fixed test benches cannot cover diverse testing needs. Companies often need to repeatedly purchase multiple sets of dedicated equipment to test different products, resulting in high investment costs, large space requirements, and low utilization of testing resources, severely restricting the efficiency and flexibility of product development. Summary of the Invention

[0005] This application provides a right-angle commutation test device, test system, and test method for transfer cases, which solves the problem that a single test bench can only be used for a single type or specification of transfer case in the prior art, improves the versatility of the existing test bench, and realizes compatible testing of multiple transfer cases.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a transfer case right-angle reversing test device, comprising a housing, wherein a reversing transmission mechanism and a speed ratio adjustment mechanism are disposed within the housing, the reversing transmission mechanism comprising an intermediate shaft and an output shaft arranged parallel to each other, and an input shaft arranged perpendicular to the intermediate shaft and the output shaft; an input gear is fixed on the input shaft and is connected to an external power source through a telescopic transmission shaft, the two ends of the telescopic transmission shaft being connected to the input shaft and the output end of the external drive mechanism respectively through universal joints; The intermediate shaft is fitted with a first intermediate shaft gear and a second intermediate shaft gear, and the output shaft is fixed with a first output gear and a second output gear; the input gear is constantly meshed with the first intermediate shaft gear, the first intermediate shaft gear is constantly meshed with the first output gear to form a first transmission path, and the second intermediate shaft gear is constantly meshed with the second output gear to form a second transmission path; The speed ratio adjustment mechanism includes a sliding sleeve that is axially slidably fitted onto the output shaft. The sliding sleeve can selectively engage with the first output gear or the second output gear to switch the transmission path.

[0007] Because this device employs a reversing transmission mechanism with switchable dual transmission paths, an axially sliding sleeve, and a telescopic transmission shaft with a universal joint, it can select different transmission paths to adapt to different speed ratio requirements by moving the sleeve during use. Furthermore, it compensates for installation errors and achieves flexible docking with the drive ends of various test benches by utilizing the telescopic transmission shaft and universal joint. This solves the problem in existing technologies where a single test bench can only accommodate a single type or specification of transfer case, significantly improving the versatility of existing test benches and enabling compatible testing of multiple transfer cases.

[0008] As a further improvement to the above solution, one end of the input shaft is provided with an input flange for connecting the test bench drive motor, and both ends of the output shaft are respectively provided with output flanges for connecting the transfer case. Thus, when using this device, it can achieve quick and reliable alignment connection with the test bench drive mechanism and the transfer case under test through standardized flange interfaces, simplifying the clamping and docking process and improving the efficiency and compatibility of the test system setup.

[0009] As a further improvement to the above solution, the sliding sleeve achieves its axial sliding through a pneumatic drive structure or an electric drive structure; thus, the device can achieve rapid and precise control of the sliding sleeve position by means of this automated drive structure during use.

[0010] As a further improvement to the above solution, a engagement tooth is provided between the first output gear and the second output gear for engaging with the sliding sleeve.

[0011] This invention also discloses a transfer case right-angle commutation test system, which includes the transfer case right-angle commutation test device as described above, and further includes: a first motor, a second motor, and a third motor. The first motor is a drive mechanism and is connected to one end of a first drive shaft via a universal joint. The other end of the first drive shaft is connected to the input end of the input shaft. The second and third motors are respectively used to connect to the two output ends of the transfer case to simulate the load applied under the working conditions of the entire vehicle. Therefore, this system can simultaneously realize the independent simulation of power input and dual-output load on an integrated platform, realistically reproducing the multi-end force conditions of the transfer case during vehicle operation, and providing a more comprehensive and reliable testing environment for the comprehensive performance evaluation of the transfer case.

[0012] As a further improvement to the above solution, a transmission is also included; the input end of the transmission is connected to the output end of the first motor, and the output end of the transmission is connected to the end of the telescopic drive shaft away from the right-angle reversing test device of the transfer case; thus, this system can simulate a complete vehicle drivetrain including the transmission and the transfer case, thereby realizing the testing of the "transmission". The comprehensive test of the transfer case's matching performance more realistically reflects the actual operating conditions such as the shifting process, torque transmission, and system efficiency.

[0013] As a further improvement to the above scheme, a first sensor, a second sensor, and a third sensor are also included. The first sensor is disposed on the transmission path between the first motor and the input shaft; the second sensor is disposed on the transmission path between the second motor and the first output end of the transfer case under test; and the third sensor is disposed on the transmission path between the third motor and the second output end of the transfer case under test, for monitoring the second output load torque. Thus, this system can measure parameters such as the speed and torque of the input drive end and the two output load ends, thereby providing a data basis for calculating the transfer case transmission efficiency, analyzing load distribution, and evaluating dynamic performance, and improving the accuracy and analyzability of the test results.

[0014] As a further improvement to the above solution, a vibration sensor is also included, which is mounted on the housing of the transfer case under test; this can effectively prevent further damage to the equipment caused by potential faults.

[0015] This invention also discloses a transfer case testing method, which uses the aforementioned transfer case right-angle commutation test system, specifically including the following steps: Step S1: Adjust the installation state of the right-angle commutation test device for the transfer case according to the specifications of the transfer case to be tested; Step S2: Install the transfer case to be tested into the test system, connect its input end to the output shaft, and connect its two output ends to the second motor and the third motor respectively; Step S3: Control the operation of the first motor, the second motor and the third motor to simulate the working conditions of the whole vehicle and perform a load test on the transfer case; Step S4: Collect rotational speed and torque data during the test using the first, second, and third sensors. As a further improvement to the above scheme, in step S4, vibration data of the transfer case housing is also collected by the vibration sensor; and when the vibration data exceeds a preset threshold, the test system is controlled to automatically alarm or stop.

[0016] As can be seen from the above technical solutions, the present invention has at least the following technical effects or advantages: Because the transfer case right-angle reversing test device disclosed in this invention adopts a reversing transmission mechanism including a switchable dual transmission path, an axially sliding sleeve, and a telescopic transmission shaft structure with a universal joint, the device can select different transmission paths by moving the sleeve to adapt to different speed ratio requirements during use. It also compensates for installation errors by using the telescopic transmission shaft and universal joint to achieve flexible docking with the drive end of various test benches. This solves the problem in the prior art that a test bench can only be adapted to a single type or specification of transfer case, significantly improving the versatility of the existing test bench and realizing compatible testing of multiple transfer cases. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the transfer case right-angle reversing test device; Figure 2 This is a schematic diagram of the transfer case right-angle commutation test system; Figure 3 This is a schematic diagram of the transmission after it has been installed on the transfer case right-angle reversing test system.

[0018] Explanation of reference numerals in the attached drawings: 1. Housing; 2. Intermediate shaft; 3. Output shaft; 4. Input shaft; 5. Input gear; 6. Telescopic drive shaft; 7. Universal joint; 8. First intermediate shaft gear; 9. Second intermediate shaft gear; 10. First output gear; 11. Second output gear; 12. Sliding sleeve; 13. Input flange; 14. Transfer case; 15. Output flange; 16. First motor; 17. Second motor; 18. Third motor; 19. Gearbox; 20. First sensor; 21. Second sensor; 22. Third sensor. Detailed Implementation The following will refer to the accompanying drawings in the embodiments of the present invention ( Figures 1 to 3 This document provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] This invention provides a transfer case right-angle commutation test apparatus, system, and method, aiming to solve the problems of poor versatility, inability to simulate real spatial layout, and inability to perform multi-condition testing in existing transfer case test benches. The apparatus, system, and method will be described in detail below.

[0020] Example 1 This embodiment discloses a transfer case right-angle commutation test device, such as... Figure 1 As shown, it includes a housing 1, within which a reversing transmission mechanism and a speed ratio adjustment mechanism are disposed. The reversing transmission mechanism includes an intermediate shaft 2 and an output shaft 3 arranged parallel to each other, and an input shaft 4 arranged perpendicular to the intermediate shaft 2 and the output shaft 3. An input gear 5 is fixed on the input shaft 4 and connected to an external power source through a telescopic transmission shaft 6. The two ends of the telescopic transmission shaft 6 are respectively connected to the input shaft 4 and the output end of the external drive mechanism through universal joints 7. A first intermediate shaft gear 8 and a second intermediate shaft gear 9 are sleeved on the intermediate shaft 2, and a first output gear 10 and a second output gear 11 are fixed on the output shaft 3. The input gear 5 is constantly meshed with the first intermediate shaft gear 8, the first intermediate shaft gear 8 is constantly meshed with the first output gear 10 to form a first transmission path, and the second intermediate shaft gear 9 is constantly meshed with the second output gear 11 to form a second transmission path. The speed ratio adjustment mechanism includes a sliding sleeve 12 axially slidably sleeved on the output shaft 3. The sliding sleeve 12 is used to selectively engage with the first output gear 10 or the second output gear 11 to switch the transmission path.

[0021] In this embodiment, the housing 1 serves as the supporting frame for the entire device, made of rigid material, and has cavities and holes for mounting various bearing seats. The input shaft 4, intermediate shaft 2, and output shaft 3 are all supported on the housing 1 by rolling bearings. One end of the input shaft 4 extends outside the housing 1 and is used to connect a telescopic drive shaft 6 via a universal joint 7. This telescopic drive shaft 6 is preferably a drive shaft with internal and external splines, which allows sliding in the length direction to compensate for installation alignment errors. Its other end is connected to an external drive motor. The input gear 5 is fixed to the portion of the input shaft 4 located inside the housing 1 by a key connection. The intermediate shaft 2 is arranged parallel to the output shaft 3. The first intermediate shaft gear 8 and the second intermediate shaft gear 9 are loosely fitted on the intermediate shaft 2 by bearings and can rotate freely relative to the intermediate shaft 2. On the output shaft 3, the first output gear 10 and the second output gear 11 are fixed by a key connection, with a distance between them. The sliding sleeve 12 engages with the external spline on the output shaft 3 via an internal spline, allowing it to rotate with the output shaft 3 and slide along its axial direction. The sides of the first output gear 10 and the second output gear 11 are provided with engagement gear rings that can mesh with the internal splines at the end of the sliding sleeve 12.

[0022] In actual operation, external power is transmitted to the input shaft 4 via the telescopic transmission shaft 6, driving the input gear 5 to rotate. The input gear 5 always drives the first intermediate shaft gear 8 to rotate. When the first speed ratio is needed, the sliding sleeve 12 is moved axially by a mechanism such as a cylinder or electric push rod, so that it meshes with the engagement gear ring on the side of the first output gear 10. At this time, the power flow is: input shaft 4 to input gear 5 to first intermediate shaft gear 8 to first output gear 10 to sliding sleeve 12 to output shaft 3, forming the first transmission path. When the second speed ratio is needed, the sliding sleeve 12 is driven to move and engage with the second output gear 11. At this time, the first intermediate shaft gear 8 idles, and the power is transmitted to the second intermediate shaft gear 9 through gear meshing. The flow path is: input shaft 4 to input gear 5 to first intermediate shaft gear 8 to second intermediate shaft gear 9 to second output gear 11 to sliding sleeve 12 to output shaft 3, forming the second transmission path. By switching the position of the sliding sleeve 12, two different transmission ratios can be achieved.

[0023] The above structure employs a telescopic drive shaft 6 with a universal joint 7, which can effectively compensate for installation alignment errors and achieve flexible connection with the drive end of various test benches. It also features a dual-speed ratio transmission path based on the switching of the sliding sleeve 12, which can cover the transmission ratio testing requirements of different transfer cases 14. Therefore, when this device is combined with an existing test bench, it can quickly adjust and switch without modifying the main structure of the test bench, making the same test bench system compatible with testing multiple models and specifications of transfer cases 14, thereby significantly improving the testing coverage and flexibility of the original test bench.

[0024] Furthermore, one end of the input shaft 4 is provided with an input flange 13 for connecting to the test bench drive motor, and both ends of the output shaft 3 are respectively provided with output flanges 15 for connecting to the transfer case 14. In this embodiment, the input flange 13 is fixed to the extended end of the input shaft 4 by bolts, which facilitates alignment and connection with the output flange 15 of the drive motor via a bolt group. Both ends of the output shaft 3 are machined with splines or flange structures for directly connecting to the input end of the transfer case 14 under test via a drive shaft to simulate its actual installation state.

[0025] In the above structure, the standardized flange interface design enables the device to be quickly and reliably integrated into various standard test benches, with convenient connection and strong interchangeability.

[0026] Furthermore, the sliding sleeve 12 achieves its axial sliding through a pneumatic drive structure or an electric drive structure. In this embodiment, the pneumatic drive structure may include a cylinder fixed to the housing 1, with the piston rod of the cylinder connected to the annular groove on the sliding sleeve 12 via a fork or connecting rod mechanism. The electric drive structure may include a ball screw mechanism driven by a servo motor, with the screw nut linked to the sliding sleeve 12 via a connecting block. The control system can precisely control the movement and positioning of the sliding sleeve 12 by controlling a solenoid valve or a servo driver.

[0027] In the above structure, the speed ratio switching is controlled by an automated drive method, which is not only convenient and labor-saving to operate, but also enables precise synchronization with the test process, thereby improving the degree of automation and efficiency of testing.

[0028] Furthermore, the first output gear 10 and the second output gear 11 are provided with engaging teeth for engaging with the sliding sleeve 12. In this embodiment, the engaging teeth are external spline gear rings machined on the right side of the first output gear 10 and the left side of the second output gear 11. The internal spline length of the sliding sleeve 12 is designed to fully mesh with the engaging teeth of either gear simultaneously, ensuring smooth and reliable power transmission.

[0029] In the above structure, the gear side engagement teeth mesh with the internal spline of the sliding sleeve 12, which is compact, transmits large torque, and the engagement and disengagement actions are rapid and accurate.

[0030] Example 2 This embodiment 2 discloses a right-angle commutation test system for a transfer case 14, such as... Figure 2 and Figure 3The figures show two typical application embodiments of the right-angle reversing test system for the transfer case 14 of the present invention. A right-angle reversing test system for the transfer case 14 includes the right-angle reversing test device for the transfer case as described in Embodiment 1, and further includes: a first motor 16, a second motor 17, and a third motor 18. The first motor 16 is a drive mechanism and is connected to one end of a first drive shaft via a universal joint 7. The other end of the first drive shaft is connected to the input end of the input shaft 4. The second motor 17 and the third motor 18 are respectively used to connect to the two output ends of the transfer case 14 to simulate the application of load under vehicle operating conditions.

[0031] In this embodiment, Figure 2 The layout for a standalone test of the transfer case 14 is shown. The first motor 16 is a drive motor, connected to the input flange 13 of the test apparatus via a retractable universal joint. The input of the transfer case 14 under test is connected to the output flange 15 of the test apparatus, and its two outputs are connected to the second motor 17 and the third motor 18, both load motors, via couplings. The first, second, and third motors 18 are preferably servo motors or variable frequency motors, possessing precise speed and torque control capabilities. The entire system is coordinated by a central control system, capable of simulating the load on the transfer case 14 under various operating conditions such as vehicle acceleration, cruising, and hill climbing.

[0032] In the above system, the three-motor layout can accurately simulate the actual force state of the transfer case 14 on the whole vehicle (input drive, independent loading of front and rear output ends), providing a highly simulated platform for testing the fatigue life and transmission efficiency of the transfer case 14.

[0033] Furthermore, the system also includes a transmission 19; the input end of the transmission 19 is connected to the output end of the first motor 16, and the output end of the transmission 19 is connected to the end of the telescopic drive shaft 6 away from the right-angle reversing test device of the transfer case. In this embodiment, as... Figure 3 As shown, a real automotive transmission 19 is added between the drive motor and the test device. The transmission 19 is mounted on an independent support frame, with its input shaft 4 connected to the first motor 16 via a drive shaft, and its output shaft 3 connected to the input shaft 4 of the test device via a telescopic drive shaft 6. This constitutes a complete drivetrain test system of "transmission 19 + transfer case 14".

[0034] In the above structure, this configuration can test the overall performance of the transfer case 14 and the transmission 19 when they are working together, as well as the impact of shift shock on the transfer case 14. The test conditions are more comprehensive and the data are closer to the actual vehicle conditions.

[0035] Furthermore, the system also includes a first sensor 20, a second sensor 21, and a third sensor 22. The first sensor 20 is disposed on the transmission path between the first motor 16 and the input shaft 4; the second sensor 21 is disposed on the transmission path between the second motor 17 and the first output end of the transfer case 14 under test; and the third sensor 22 is disposed on the transmission path between the third motor 18 and the second output end of the transfer case 14 under test, for monitoring the second output load torque. In this embodiment, the first sensor 20 is a torque-speed sensor, installed on the output shaft 3 of the drive motor or on the connecting transmission shaft, for real-time and accurate measurement of the speed and torque input to the test device. The second sensor 21 and the third sensor 22 are also torque-speed sensors, respectively installed on the transmission shafts connecting the two output ends of the transfer case 14, for accurate measurement of the load torque and speed of the two output ends. All sensor signals are connected to the data acquisition system.

[0036] In the above structure, through the arrangement of high-precision sensors, the system can acquire dynamic data of each key point of the transmission chain in real time, providing a direct data source for calculating the transmission efficiency of the transfer case 14 and analyzing the load distribution, which is the basis for quantitative performance evaluation.

[0037] Furthermore, the system also includes a vibration sensor mounted on the housing of the transfer case 14 under test. In this embodiment, the vibration sensor is preferably an accelerometer, fixed to a key location near the bearing seat or gearbox on the surface of the housing 1 of the transfer case 14 under test by magnetic mounting or adhesive, for monitoring the vibration intensity and characteristic frequency inside the transfer case 14 during the test. In the above structure, vibration monitoring is an important means of achieving condition monitoring and fault early warning. By analyzing changes in vibration signals, potential faults such as gear pitting and bearing wear can be detected early, allowing for timely alarms or shutdowns to avoid equipment damage, while also providing feedback for the reliability design of the transfer case 14.

[0038] Example 3 This embodiment discloses a transfer case testing method, which adopts the right-angle commutation test system for transfer case 14 as described in Embodiment 2, and includes the following steps: Step S1: Adjust the installation state of the right-angle reversing test device for the transfer case 14 according to its specifications. Step S2: Install the transfer case 14 to be tested into the test system, connect its input end to the output shaft 3, and connect its two output ends to the second motor 17 and the third motor 18 respectively. Step S3: Control the first motor 16, the second motor 17 and the third motor 18 to run, so as to simulate the working conditions of the whole vehicle and perform a load test on the transfer case 14. Step S4: Collect rotational speed and torque data during the test using the first sensor 20, the second sensor 21, and the third sensor 22.

[0039] In this embodiment, step S1 specifically includes: adjusting the height of the entire housing 1 by adjusting the support structure at the bottom of the device according to the center height and center distance of the input and output ends of the transfer case 14 under test; and fine-tuning the height of the output flange 15 by adjusting the mounting structure on the side of the output shaft 3 bearing seat to ensure perfect alignment with the input end of the transfer case 14. In step S2, it is necessary to ensure that all connecting flanges are securely fastened and that there is no interference with the drive shaft. In step S3, the control system is programmed to load a preset operating condition spectrum, such as a cyclically changing speed and torque curve. In step S4, the data acquisition system synchronizes with the control system to record the readings of all sensors in real time.

[0040] In actual operation, before the test begins, the control system drives the sliding sleeve 12 to select the corresponding transmission path of the test device according to the speed ratio of the transfer case 14, so that the speed ratio relationship of the entire transmission chain meets the simulation requirements. During the test, the control system calculates and displays the transmission efficiency of the transfer case 14 in real time based on the input torque measured by the first sensor 20 and the output torque measured by the second and third sensors 22. At the same time, the signal from the vibration sensor is continuously monitored.

[0041] Furthermore, in step S4, vibration data of the transfer case 14 housing 1 is collected by the vibration sensor; and when the vibration data exceeds a preset threshold, the test system automatically alarms or shuts down. In this embodiment, the preset threshold can be set based on historical data or the health status baseline of the transfer case 14, and can be the effective value of vibration acceleration or the amplitude of a specific fault characteristic frequency. When the real-time monitored vibration data exceeds the threshold multiple times consecutively, or shows a sharp increase, the control system will trigger an audible and visual alarm and automatically execute a safety shutdown procedure, cutting off the power supply to the drive motor and unloading the load motor.

[0042] In the description of this invention, the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only to describe the invention and not to require the invention to be constructed or operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" in this invention should be interpreted broadly. For example, they can refer to a connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms based on the specific circumstances.

[0043] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in its embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A test device for right-angle commutation of a transfer case, characterized in that, The device includes a housing (1), and a reversing transmission mechanism and a speed ratio adjustment mechanism are provided inside the housing (1). The reversing transmission mechanism includes an intermediate shaft (2) and an output shaft (3) arranged parallel to each other, and an input shaft (4) arranged perpendicular to the intermediate shaft (2) and the output shaft (3). An input gear (5) is fixed on the input shaft (4) and is connected to an external power source through a telescopic transmission shaft (6). The two ends of the telescopic transmission shaft (6) can be connected to the input shaft (4) and the output end of the drive mechanism through universal joints (7). The intermediate shaft (2) is fitted with a first intermediate shaft gear (8) and a second intermediate shaft gear (9), and the output shaft (3) is fixed with a first output gear (10) and a second output gear (11); the input gear (5) is constantly meshed with the first intermediate shaft gear (8), the first intermediate shaft gear (8) and the first output gear (10) are constantly meshed to form a first transmission path, and the second intermediate shaft gear (9) and the second output gear (11) are constantly meshed to form a second transmission path; The speed ratio adjustment mechanism includes a sliding sleeve (12) that is axially slidably fitted on the output shaft (3). The sliding sleeve (12) can selectively engage with the first output gear (10) or the second output gear (11) to switch the transmission path.

2. The transfer case right-angle commutation test device according to claim 1, characterized in that, One end of the input shaft (4) is provided with an input flange (13) for connecting the test bench drive mechanism, and both ends of the output shaft (3) are respectively provided with output flanges (15) for connecting the transfer case (14).

3. The transfer case right-angle commutation test device according to claim 2, characterized in that, The sliding sleeve (12) achieves axial sliding through a pneumatic drive structure or an electric drive structure.

4. The transfer case right-angle commutation test device according to claim 3, characterized in that, The first output gear (10) and the second output gear (11) are provided with engaging teeth for engaging with the sliding sleeve (12).

5. A transfer case right-angle commutation test system, characterized in that, The transfer case right-angle commutation test apparatus, as described in any one of claims 1 to 4, further includes: The first motor (16), the second motor (17), and the third motor (18) are a drive mechanism and are connected to one end of the first drive shaft through a universal joint (7). The other end of the first drive shaft is connected to the input end of the input shaft (4). The second motor (17) and the third motor (18) are respectively connected to the two output ends of the transfer case (14).

6. The transfer case right-angle commutation test system according to claim 5, characterized in that, It also includes a transmission (19); the input end of the transmission (19) is connected to the output end of the first motor (16), and the output end of the transmission (19) is connected to the end of the telescopic drive shaft (6) away from the right-angle reversing test device of the transfer case.

7. The transfer case right-angle commutation test system according to claim 5 or 6, characterized in that, It also includes a first sensor (20), a second sensor (21) and a third sensor (22). The first sensor (20) is located on the transmission path between the first motor (16) and the input shaft (4); the second sensor (21) is located on the transmission path between the second motor (17) and the first output end of the transfer case (14) under test; and the third sensor (22) is located on the transmission path between the third motor (18) and the second output end of the transfer case (14) under test.

8. The transfer case right-angle commutation test system according to claim 7, characterized in that, It also includes a vibration sensor, which is mounted on the housing of the transfer case (14) under test.

9. A test method for a transfer case, characterized in that, The transfer case right-angle commutation test system as described in any one of claims 5 to 8 includes the following steps: Step S1: Adjust the installation status of the right-angle reversing test device for the transfer case according to the specifications of the transfer case (14) to be tested; Step S2: Install the transfer case (14) to be tested into the test system, connect its input end to the output shaft (3), and connect its two output ends to the second motor (17) and the third motor (18) respectively. Step S3: Control the first motor (16), the second motor (17) and the third motor (18) to run in order to simulate the working conditions of the whole vehicle and perform a loading test on the transfer case (14); Step S4: The rotational speed and torque data during the test are collected through the first sensor (20), the second sensor (21) and the third sensor (22).

10. The transfer case test method according to claim 9, characterized in that, In step S4, vibration data of the housing (1) of the transfer case (14) is also collected by the vibration sensor; and when the vibration data exceeds a preset threshold, the test system is controlled to automatically alarm or stop.

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