A synchronizer static gear shifting performance testing device and method

Abstract

The present application relates to the technical field of mechanical transmission test, and particularly relates to a synchronizer static gear shifting performance test device and method, the method comprising: installing a measured synchronizer assembly (113) and a shaft assembly (11); adjusting the locking nut (12) of a resistance simulation loading module, applying a pre-tightening force to a friction ring (13), and measuring the torque required for the rotation of the shaft assembly (11) until a preset system resistance torque value is reached; driving a ball screw mechanism (192), driving a shift shaft assembly (17) to move axially through a connecting plate (191), and pushing the measured synchronizer assembly (113) to perform a gear shifting action; collecting the input torque of the ball screw mechanism (192) in real time, and calculating the axial gear shifting force accordingly; simultaneously measuring the displacement of the connecting plate (191); establishing a corresponding relationship between the gear shifting force and the gear shifting displacement, and generating a performance test curve. The present application significantly improves the working condition authenticity and data accuracy of the synchronizer static gear shifting performance test.

Description

Technical Field

[0001] This application relates to the field of mechanical transmission testing technology, and in particular to a device and method for testing the static shifting performance of a synchronizer. Background Technology

[0002] The synchronizer assembly is a core component of the transmission, and its static shifting performance (such as shifting force and shifting travel) directly affects the driving feel of the entire vehicle. During research and development and production, the synchronizer must undergo rigorous performance testing.

[0003] Existing testing technologies have the following main drawbacks:

[0004] Limited testing conditions: Existing static test benches typically only test the synchronizer unit, neglecting the impact of the system resistance torque generated by bearings, oil seals, and gear meshing on shifting performance after the synchronizer is installed in the transmission assembly. This leads to a significant deviation between bench test data and actual vehicle operating conditions.

[0005] Lack of quantitative simulation methods: Although some equipment has increased load, it is often impossible to quantitatively adjust the magnitude of the system resistance torque, and it is impossible to study the specific impact of different resistance torque levels on shifting performance.

[0006] Low precision of drive method: Traditional drive methods mostly use pneumatic or hydraulic cylinders for direct actuation, making it difficult to precisely control minute shift strokes and accurately calculate the actual axial thrust. The force output of pneumatic / hydraulic cylinders is usually unstable, affecting the repeatability of test data.

[0007] Therefore, there is an urgent need for a test device and method for the static shifting performance of synchronizers that can simulate the resistance torque of the transmission system, accurately measure the relationship between shifting force and displacement, and is simple in structure and easy to operate. Summary of the Invention

[0008] The purpose of this invention is to provide a synchronizer static shifting performance testing device and method to solve the problems that existing synchronizer static testing devices cannot simulate the resistance torque of the transmission system and the shifting force measurement is inaccurate.

[0009] This invention provides the following solution:

[0010] A synchronizer static shifting performance testing device includes:

[0011] Supporting entity;

[0012] The tested assembly module includes a shaft assembly 11 and a tested synchronizer assembly 113 mounted thereon. The shaft assembly 11 is rotatably supported on the support body via a bearing 15.

[0013] A resistance simulation loading module is disposed at the axial positioning end of the shaft assembly 11. The resistance simulation loading module includes a locking nut 12, a friction ring 13, and a stationary mating part. The friction ring 13 is sleeved on the shaft assembly, and the locking nut 12 is configured to apply an axial preload to the friction ring 13 to generate an adjustable frictional resistance torque between the friction ring 13 and the stationary mating part, thereby simulating the resistance of the transmission system.

[0014] The shift drive module includes a ball screw mechanism 192, a connecting plate 191, and a shift fork shaft assembly 17. The ball screw mechanism 192 is mounted on the support body, and its motion output end is connected to the shift fork shaft assembly 17 through the connecting plate 191. The shift fork shaft assembly 17 is configured to drive the synchronizer assembly 113 under test to move axially.

[0015] Furthermore, the support body includes a front support plate 16, a rear support plate 26, and a support rod 24 connecting the front support plate 16 and the rear support plate 26; the shaft assembly 11 is rotatably supported on the front support plate 16 via a bearing 15, and the ball screw mechanism 192 is fixed on the rear support plate 26.

[0016] Furthermore, the assembly module under test also includes a low gear 112 and a high gear 114, and the synchronizer assembly under test 113 is disposed between the low gear 112 and the high gear 114 and is splinedly connected to the shaft assembly 11.

[0017] Furthermore, the stationary mating component is the bearing cover plate 14 or the outer ring end face of the bearing 15; the friction ring 13 is made of aluminum alloy or non-metallic friction material.

[0018] Furthermore, the shift fork shaft assembly 17 is fixed to the connecting plate 191 by set bolts 18.

[0019] Furthermore, the input end of the ball screw mechanism 192 is equipped with a torque input interface for connecting a torque wrench; the device calculates the axial shifting force F by measuring the torque value T at the input end and combining it with the formula F = (2π×T×η) / P, where η is the transmission efficiency and P is the screw lead.

[0020] According to another aspect of the present invention, a method for testing the static shifting performance of a synchronizer is provided, comprising:

[0021] S1, Install the synchronizer assembly 113 under test and the shaft assembly 11;

[0022] S2, adjust the locking nut 12 of the resistance simulation loading module to apply preload to the friction ring 13, and measure the torque required for the rotation of the shaft assembly 11 until the preset system resistance torque value is reached;

[0023] S3 drives the ball screw mechanism 192, which drives the shift fork shaft assembly 17 to move axially through the connecting plate 192, and pushes the synchronizer assembly 113 under test to perform a shifting action.

[0024] S4: Real-time acquisition of the input torque of the ball screw mechanism 192, and calculation of the axial shifting force accordingly; at the same time, measurement of the displacement of the connecting plate 191.

[0025] S5 establishes the correspondence between shifting force and shifting displacement, and generates performance test curves.

[0026] Furthermore, the resistance torque calibration in step S2 specifically includes: using a torque wrench to rotate the shaft assembly 11 while adjusting the preload of the locking nut 12 until the torque value required to rotate the shaft assembly 11 is equal to the preset system resistance torque value.

[0027] Furthermore, the calculation of axial shifting force in step S4 specifically includes: reading the torque value T displayed by the torque wrench connected to the input end of the ball screw mechanism 192, and calculating the shifting force F in real time.

[0028] Further, the measurement of the displacement of the connecting plate 191 in step S4 specifically includes: using a displacement sensor or vernier caliper to measure the change in distance ΔS between the measuring reference surface on the connecting plate 191 and the reference surface on the support body, and recording the change ΔS as the shift stroke.

[0029] The above solution achieves the following beneficial technical effects:

[0030] This invention utilizes a resistance simulation loading module to apply an adjustable axial preload to the friction ring using a locking nut. This generates a stable frictional resistance torque between the friction ring and the stationary mating parts, effectively simulating the system resistance torques such as bearing rolling resistance, oil seal resistance, and gear meshing resistance within the transmission. This design overcomes the shortcomings of traditional static test benches that only test the synchronizer unit and ignore the influence of system resistance. It ensures that the bench test data closely matches actual vehicle operating conditions, significantly improving the realism of the test and its engineering reference value.

[0031] In particular, this invention employs a ball screw mechanism as the core of the shift drive, leveraging its stable transmission efficiency and precisely calculable thrust. By measuring the input torque and combining it with formulas, the axial shift force can be derived in real time and with high accuracy, avoiding the thrust instability problems caused by gas compression and friction fluctuations in traditional cylinder or hydraulic cylinder drive methods. Simultaneously, by directly measuring the displacement of the connecting plate using a displacement sensor or vernier caliper, high-resolution shift stroke data can be obtained, thereby generating an accurate shift force-displacement characteristic curve, ensuring the repeatability and consistency of the test data.

[0032] In particular, this invention allows for stepless and convenient setting of different system resistance torque levels by adjusting the tightening torque of the locking nut. This enables quantitative research into the influence of the resistance torque on the shift feel and shift force of the synchronizer, providing strong data support for the optimized design of the synchronizer and the matching of the transmission system. Furthermore, the entire device is implemented using a purely mechanical structure, eliminating the need for a complex electro-hydraulic servo system. It boasts advantages such as low cost, convenient maintenance, and simple operation, making it suitable for both laboratory research and testing and rapid quality inspection on production lines, demonstrating promising prospects for widespread application. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of a synchronizer static shifting performance testing device according to an embodiment of the present invention.

[0034] Figure 2 for Figure 1 The exploded view of the synchronizer static shifting performance test device is shown.

[0035] Figure 3 This is a schematic diagram of a shaft assembly according to an embodiment of the present invention.

[0036] Figure 4 This is an exploded structural diagram of a ball screw with a connecting plate according to an embodiment of the present invention.

[0037] Figure 5 This is a flowchart of the synchronizer static shifting performance test method of the present invention. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be understood that the terms "front," "rear," "axial," etc., indicating orientation or positional relationships are based on the orientation that the operator is accustomed to facing during testing, and are only for the convenience and simplification of description. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "installation," "connection," and "fixing" should be interpreted broadly, for example, referring to a fixed connection, a detachable connection, or an integral connection, unless otherwise explicitly specified and limited.

[0040] This embodiment first provides a detailed description of the specific structure of the synchronizer static shifting performance testing device provided by the present invention.

[0041] like Figure 1 and Figure 2 As shown, the testing device of the present invention mainly consists of a support body, a test assembly module, a resistance simulation loading module, and a gear shifting drive module.

[0042] like Figure 1 As shown, the support structure provides a rigid support foundation for the entire testing device. In this embodiment, the support structure includes a front support plate 16, a rear support plate 26, and support rods 24 connecting the front support plate 16 and the rear support plate 26. The front support plate 16 and the rear support plate 26 are fixed in parallel and spaced apart by multiple support rods 24, forming a stable frame structure. It should be noted that the number of support rods 24 can be set to three, four, or more according to actual rigidity requirements. In this embodiment, four rods are preferred, distributed at the four corners of the front support plate 16 and the rear support plate 26.

[0043] See also Figure 1 and Figure 3 The tested assembly module includes a shaft assembly 11, a synchronizer assembly 113 mounted thereon, and a mating gear. The shaft assembly 11 is rotatably supported on the support body via a bearing 15. Specifically, in this embodiment, the shaft assembly 11 is rotatably supported on a front support plate 16 via a bearing 15, the outer ring of the bearing 15 mates with a bearing seat hole on the front support plate 16, and the inner ring mates with the journal of the shaft assembly 11.

[0044] To simulate the real gear system environment inside a transmission, such as Figure 3 As shown, the tested assembly module also includes a low-gear 112 and a high-gear 114. The tested synchronizer assembly 113 is disposed between the low-gear 112 and the high-gear 114 and is splinedly connected to the shaft assembly 11. The low-gear 112 and the high-gear 114 are sleeved on the shaft assembly 11 and can rotate freely relative to the shaft. The gear hub of the tested synchronizer assembly 113 is fixed to the shaft assembly 11 by a spline, and the engagement sleeve can slide axially under the drive of the shift fork, engaging with the engagement gear ring of the low-gear 112 or the high-gear 114 respectively, thereby realizing gear shifting simulation.

[0045] See Figure 1 and Figure 2 The resistance simulation loading module is located at the axial positioning end of the shaft assembly 11 and is used to simulate the system resistance torque generated by bearings, oil seals, and gear meshing inside the transmission. This module includes a lock nut 12, a friction ring 13, and stationary mating parts.

[0046] The friction ring 13 is sleeved on the shaft assembly 11. Preferably, the friction ring 13 is sleeved on the outer side of the journal where the bearing 15 is located. The locking nut 12 is screwed onto the end thread of the shaft assembly 11 and is configured to apply an axial preload to the friction ring 13. When the locking nut 12 is tightened, its end face pushes the friction ring 13 to move axially, causing the end face of the friction ring 13 to press against the stationary mating part.

[0047] The stationary mating component is a part that is stationary relative to the shaft assembly 11. In one embodiment of the invention, such as Figure 1 As shown, the stationary fitting component is a bearing cover plate 14 fixed to the front support plate 16. The bearing cover plate 14 is fixed to the front support plate 16 by bolts and presses down on the outer ring of the bearing 15. In another embodiment not shown, the stationary fitting component can also be the outer ring end face of the bearing 15 directly, in which case there is no need to provide a bearing cover plate 14.

[0048] When the locking nut 12 is preloaded, pressure is generated between the friction ring 13 and the stationary mating parts. Since the shaft assembly 11, together with the friction ring 13, can rotate while the stationary mating parts remain stationary, a frictional resistance torque is generated on the relatively moving contact surface. The magnitude of this resistance torque is proportional to the preload of the locking nut 12. By adjusting the tightening torque of the locking nut 12, the resistance torque value can be changed steplessly and quantitatively, thereby simulating the resistance of the transmission system under different operating conditions.

[0049] To improve the stability and wear resistance of the friction coefficient, the friction ring 13 is preferably made of aluminum alloy or non-metallic friction materials (such as polytetrafluoroethylene, graphite composites, etc.). These materials have stable frictional characteristics, which can ensure that the resistance torque remains constant during the test.

[0050] See Figure 1 , Figure 2 and Figure 4 The shift drive module provides precise and controllable shift axial thrust. This module includes a ball screw mechanism 192, a connecting plate 191, and a shift fork shaft assembly 17.

[0051] The ball screw mechanism 192 is mounted on the support body. In this embodiment, as... Figure 1 As shown, the ball screw mechanism 192 is fixed on the rear support plate 26, and its axis is parallel to the axis of the shaft assembly 11. The ball screw mechanism 192 includes a screw, a screw nut, and an input end interface. The screw is mounted on the rear support plate 26 through a bearing seat and can rotate freely; the screw nut is threaded with the screw, and when the screw rotates, the nut moves axially.

[0052] The shift fork shaft assembly 17 is connected to the connecting plate 191, and the connecting plate 191 is fixedly connected to the motion output end (i.e., the screw nut) of the ball screw mechanism 192. Specifically, as shown... Figure 2 and Figure 4 As shown, the shift fork shaft assembly 17 is fixed to the connecting plate 191 by set bolts 18, and the connecting plate 191 is connected to the nut seat of the ball screw mechanism 192 by screws. When the ball screw mechanism 192 rotates, the nut drives the connecting plate 191 and the shift fork shaft assembly 17 to move axially. The shift fork foot at the front end of the shift fork shaft assembly 17 engages with the annular groove of the coupling sleeve of the synchronizer assembly 113 under test, thereby driving the coupling sleeve to move axially and realizing the shifting action.

[0053] To accurately measure and calculate the axial shifting force, the input end of the ball screw mechanism 192 is equipped with a torque input interface. This interface can be an internal hexagonal hole, an external hexagonal head, or a lever arm, for connecting a torque wrench. The operator applies the input torque T through the torque wrench. According to the transmission principle of the ball screw, the axial thrust F and the input torque T satisfy the following relationship:

[0054] F = (2π×T×η) / P;

[0055] Where η is the transmission efficiency of the ball screw (usually between 0.90 and 0.95, which can be calibrated through the product manual or actual measurement), and P is the lead of the screw (unit: meter).

[0056] The present invention also provides a method for testing the static shifting performance of a synchronizer using the apparatus described in any of the above embodiments. See also Figure 5 The method includes the following steps:

[0057] Step S1: Install the synchronizer assembly under test and the first axis assembly.

[0058] In this embodiment of the invention, the low-gear 112, the synchronizer assembly under test 113, and the high-gear 114 are sequentially installed onto the shaft assembly 11, wherein the gear hub of the synchronizer assembly under test 113 is splined with the shaft assembly 11. The assembled shaft assembly 11 is then installed onto the front support plate 16 via bearing 15, and the bearing cover plate 14 is fixed. The shift fork of the shift fork shaft assembly 17 is inserted into the engagement ring groove of the synchronizer assembly under test 113, and the shift fork shaft assembly 17 is fixed to the connecting plate 191 using set bolts 18. It is ensured that the axes of the ball screw mechanism 192, the connecting plate 191, and the shift fork shaft assembly 17 are parallel to the axis of the shaft assembly 11.

[0059] Step S2: Adjust the resistance simulation loading module to calibrate the system resistance torque.

[0060] In this embodiment of the invention, a torque wrench is used to hold the end of a shaft assembly 11 (e.g., the hexagonal head on the outside of the lock nut 12), and the shaft assembly 11 is slowly rotated while another torque wrench or socket wrench is used to adjust the tightening torque of the lock nut 12. As the lock nut 12 is gradually tightened, the pressure between the friction ring 13 and the stationary mating part increases, and the torque required to rotate the shaft assembly 11 also increases accordingly. The reading on the torque wrench is observed until the reading reaches the preset system resistance torque value (e.g., 1.5 N·m, 2.0 N·m, etc.). At this point, the adjustment of the lock nut 12 is stopped, and its position is kept unchanged, thus completing the calibration of the system resistance torque. In this way, any level of resistance torque can be set, thereby studying the effect of different resistances on shifting performance.

[0061] Step S3: Drive the ball screw mechanism to perform the gear shifting action.

[0062] In this embodiment of the invention, a torque wrench is connected to the input end of the ball screw mechanism 192. The operator slowly and uniformly rotates the torque wrench, causing the screw of the ball screw mechanism 192 to rotate. The nut drives the connecting plate 191 and the shift fork shaft assembly 17 to move axially. The shift fork of the shift fork shaft assembly 17 pushes the engagement sleeve from the neutral position to one side (e.g., towards the low gear 112) until the engagement sleeve is fully engaged with the engagement gear ring of the low gear 112, completing the gear engagement action. If it is necessary to test disengaging the gear or shifting to a higher gear, the torque wrench can be rotated in the opposite direction.

[0063] Step S4: Real-time acquisition of input torque and calculation of axial shifting force, while measuring displacement.

[0064] In this embodiment of the invention, this step is further subdivided into the measurement and calculation of two parameters: force and displacement.

[0065] Force Measurement and Calculation: Throughout the gear shifting process, the torque value T displayed on the torque wrench is continuously read. Based on the aforementioned formula: F = (2π×T×η) / P, the axial shifting force F is calculated in real time. For example, assuming the selected ball screw lead P = 0.005 m and the transmission efficiency η = 0.92, when the torque wrench reading T = 2 N·m, substituting into the formula yields: F = 2 × 3.14 × 2 × 0.92 / 0.005 ≈ 2310 N, meaning the axial shifting force is approximately 2310 N. This demonstrates that a relatively small input torque can generate a large axial thrust, achieving precise control of "small torque to large thrust".

[0066] Displacement Measurement: Using a displacement sensor (such as a laser displacement sensor, optical encoder) or high-precision vernier caliper, measure the change in distance ΔS between the measuring reference surface on the connecting plate 191 and the reference surface on the support body. For example, the displacement sensor can be fixed on the front support plate 16, with its probe resting on the end face of the connecting plate 191. During gear shifting, the sensor directly outputs the displacement change. Alternatively, a vernier caliper can be used to manually read the difference between the initial and final positions. This change ΔS is the stroke of the shift fork shaft assembly 17, which is the shifting displacement of the coupling sleeve of the synchronizer assembly 113 being measured.

[0067] Step S5: Establish the correspondence between shifting force and shifting displacement, and generate performance test curves.

[0068] The series of shifting forces F and corresponding displacements ΔS recorded in step S4 are plotted as a "shifting force-displacement" characteristic curve with displacement as the abscissa and force as the ordinate. A typical curve will show that: in neutral, the force is close to zero; as the displacement increases, the engaging sleeve begins to push the locking mechanism, and the force rapidly rises to a peak (i.e., synchronizing force); then, after the synchronization phase, the force decreases slightly; finally, the engaging force rises again. By analyzing the characteristics of this curve, such as the peak height, synchronizing stroke length, and force stability, the static shifting performance of the tested synchronizer assembly under different system resistance torques can be quantitatively evaluated.

[0069] Specifically, the performance test curve uses the shift stroke (i.e., displacement change ΔS) as the abscissa and the axial shift force F as the ordinate, completely recording the force-displacement changes from neutral to gear engagement. When evaluating the synchronizer's static shifting performance, feature nodes corresponding to the gear engagement mechanical process are identified and extracted from the curve, specifically including the following steps:

[0070] Identify the pre-lock and primary dial point:

[0071] The curve rises from the neutral baseline to the first significant slope change or small fluctuation plateau area. This point corresponds to the position where, after the engaging sleeve overcomes the slider clearance (δ1) and approach distance (t), the slider begins to compress the compression spring and climbs along the inclined surface of the sleeve groove, about to enter the locking state. The displacement value at this point reflects the shift idle travel, and the force value at this point reflects the pre-locking resistance. Extract the locking position force value and the synchronous travel:

[0072] The curve continues to rise to the first peak point, which corresponds to the lock-up position of the synchronizer—that is, the instant when the spline end face of the coupling sleeve and the locking surface of the synchronizer ring are just abutted, and the synchronizer ring begins to synchronize the rotational speed by relying on frictional torque. This peak force is denoted as the locking force F_lock, and its magnitude directly affects the shifting feel. The displacement increment from the pre-lock point to the lock point is the synchronizer ring engagement amount (δ3) and the initial travel of the synchronization process.

[0073] Identify the synchronization completion and the starting point of the secondary dial:

[0074] After the peak locking force, the curve typically dips briefly or forms a plateau, corresponding to the synchronization process (speed synchronization phase). When the curve rises significantly again and reaches a second peak, this point corresponds to the starting point where the spline end face of the engaging sleeve crosses the synchronizing ring, begins contact with the chamfered spline surface of the gear ring to be engaged, and initiates a secondary shift. This second peak force is denoted as the secondary shift force F_shift, and its value reflects the quality of the chamfering initiation performance.

[0075] Determine the completion of meshing and the end of the full stroke:

[0076] After the peak force of the second shift ring, the curve drops rapidly as the engagement sleeve slides into the spline of the gear ring. When the force value drops back to near the neutral baseline or a clear step terminates, this point corresponds to the position where the engagement sleeve and gear ring are fully engaged and the shifting stroke ends (i.e., the shifting stroke L, corresponding to the total stroke of 13.5mm stopped due to the limit switch in the paper). The total displacement from the shift start point to this end point is the static shifting total stroke S_total.

[0077] Curve characteristics and defect identification:

[0078] If an abnormal spike or violent vibration exceeding 25% of the locking force occurs before the locking position or during synchronization, it is determined that the slider or compression spring has defects such as jamming or burrs in the groove machining.

[0079] If the ratio of the peak value of the secondary shift ring force F_shift to the locking force F_lock exceeds the preset range of 0.8~1.2, it is determined that the tooth end chamfer or the locking angle of the synchronizing ring is poorly matched.

[0080] If the total stroke S_total deviates from the theoretical shift stroke L (13.5mm) by more than ±1mm, it is determined that there is an abnormality in the assembly dimension chain or axial limit.

[0081] Pass / Fail Judgment:

[0082] The extracted locking force F_lock, secondary shift ring force F_shift, total stroke S_total, and curve smoothness features are compared with the pre-stored standard sample curve or historical qualified data threshold (exemplary tolerance range: ±15% of each feature value). If all features are within the tolerance range and there are no defective waveforms as described above, the synchronizer's static shifting performance is deemed qualified; otherwise, it is deemed unqualified, and the corresponding failure mode prompt is output according to the abnormal feature type.

[0083] Preferably, the above-mentioned feature point identification and parameter calculation are automatically performed by a computer and data acquisition system to generate a test curve graph and evaluation report containing feature annotations.

[0084] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A device for testing the static shifting performance of a synchronizer, characterized in that, include: Supporting entity; The tested assembly module includes a shaft assembly (11) and a tested synchronizer assembly (113) mounted thereon. The shaft assembly (11) is rotatably supported on the support body by bearings (15). A resistance simulation loading module is disposed at the axial positioning end of the shaft assembly (11). The resistance simulation loading module includes a locking nut (12), a friction ring (13), and a stationary mating part. The friction ring (13) is sleeved on the shaft assembly. The locking nut (12) is configured to apply an axial preload to the friction ring (13) to generate an adjustable frictional resistance torque between the friction ring (13) and the stationary mating part, thereby simulating the resistance of the transmission system. The shift drive module includes a ball screw mechanism (192), a connecting plate (191), and a shift fork shaft assembly (17). The ball screw mechanism (192) is mounted on the support body, and its motion output end is connected to the shift fork shaft assembly (17) through the connecting plate (191). The shift fork shaft assembly (17) is configured to drive the synchronizer assembly (113) under test to move axially.

2. The synchronizer static shifting performance testing device according to claim 1, characterized in that, The supporting body includes a front support plate (16), a rear support plate (26), and a support rod (24) connecting the front support plate (16) and the rear support plate (26); the shaft assembly (11) is rotatably supported on the front support plate (16) by a bearing (15), and the ball screw mechanism (192) is fixed on the rear support plate (26).

3. The synchronizer static shifting performance testing device according to claim 1, characterized in that, The tested assembly module also includes a low gear (112) and a high gear (114). The tested synchronizer assembly (113) is disposed between the low gear (112) and the high gear (114) and is splinedly connected to the shaft assembly (11).

4. The synchronizer static shifting performance testing device according to claim 1, characterized in that, The stationary mating part is the bearing cover plate (14) or the outer ring end face of the bearing (15); the friction ring (13) is made of aluminum alloy or non-metallic friction material.

5. The synchronizer static shifting performance testing device according to claim 1, characterized in that, The shift fork shaft assembly (17) is fixed to the connecting plate (191) by a set bolt (18).

6. The synchronizer static shifting performance testing device according to claim 5, characterized in that, The input end of the ball screw mechanism (192) is equipped with a torque input interface for connecting a torque wrench; the device calculates the axial shifting force F by measuring the torque value T at the input end and combining it with the formula F = (2π×T×η) / P, where η is the transmission efficiency and P is the screw lead.

7. A method for testing the static shifting performance of a synchronizer, applied to the synchronizer static shifting performance testing apparatus as described in any one of claims 1-6, characterized in that, include: S1, Install the synchronizer assembly (113) and the shaft assembly (11) under test. S2, adjust the locking nut (12) of the resistance simulation loading module, apply preload to the friction ring (13), and measure the torque required for the rotation of the shaft assembly (11) until the preset system resistance torque value is reached; S3, drive the ball screw mechanism (192), drive the shift fork shaft assembly (17) to move axially through the connecting plate (191), and push the synchronizer assembly (113) under test to perform shifting action; S4, real-time acquisition of the input torque of the ball screw mechanism (192), and calculation of the axial shifting force accordingly; at the same time, measurement of the displacement of the connecting plate (191); S5 establishes the correspondence between shifting force and shifting displacement, and generates performance test curves.

8. The method for testing the static shifting performance of a synchronizer according to claim 7, characterized in that, The resistance torque calibration in step S2 specifically includes: using a torque wrench to rotate the shaft assembly (11) while adjusting the preload of the locking nut (12) until the torque required to rotate the shaft assembly (11) is equal to the preset system resistance torque value.

9. The method for testing the static shifting performance of a synchronizer according to claim 7, characterized in that, The calculation of axial shifting force in step S4 specifically includes: reading the torque value T displayed by the torque wrench connected to the input end of the ball screw mechanism (192), and calculating the shifting force F in real time.

10. The method for testing the static shifting performance of a synchronizer according to claim 7, characterized in that, The measurement of the displacement of the connecting plate (191) in step S4 specifically includes: using a displacement sensor or vernier caliper to measure the change in distance ΔS between the measuring reference surface on the connecting plate (191) and the reference surface on the support body, and recording the change ΔS as the shift stroke.

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