A special short frame and test bench for cab vibration durability test

Abstract

The present application discloses a special short frame and a test bench for cab vibration durability test, which relates to the technical field of cab vibration durability test. The special short frame includes two longitudinal beams, a first cross beam, a second cross beam and a third cross beam. The longitudinal beams and the first cross beam are adjusted to be the same as those of the actual vehicle, and both ends of the first cross beam are connected to the two longitudinal beams by the same connection method as the front cross beam of the actual vehicle; both the second cross beam and the third cross beam are customized cross beams with adjustable lengths; both ends of the customized cross beam can swing up and down relative to the two longitudinal beams by a certain angle; the center line of the second cross beam coincides with the connecting line of the front vibration contact position, and the center line of the third cross beam coincides with the connecting line of the rear vibration contact position. The special short frame and the test bench of the present application adjust the longitudinal beams and the first cross beam to be the same as those of the actual vehicle, change the positions and structures of the second cross beam and the third cross beam, reduce the torsional stiffness of itself and increase the lateral bending stiffness of itself, and improve the accuracy of the cab vibration durability test.

Description

Technical Field

[0001] This application relates to the technical field of cab vibration durability testing, and specifically relates to a special short frame and a test bench for cab vibration durability testing. Background Art

[0002] Currently, for the road simulation vibration durability test of commercial vehicle cabs, the commercial vehicle cab needs to be assembled on a special short frame (equivalent to half of the real vehicle frame) through a suspension system, and 7 actuators are connected to this special short frame through L-plate fixtures. Specifically, the special short frame includes two longitudinal beams, and each longitudinal beam has two vibration contact positions at the front and rear.

[0003] In the related art, the traditional special short frame is mainly Figure 1 a parallel structure. Its longitudinal beams 4 all adopt a double-layer beam structure with a thickness of 8mm + 5mm, and the strength of the longitudinal beams is sufficient. A circular tube beam is used as the second cross beam 2 in the middle, and the second cross beam 2 is arranged near the middle position of the transverse connection line of the vibration contact positions of the two longitudinal beams 4 ( Figure 1 and Figure 2 the left dotted line and the right dotted line in the figure); the third cross beam 3 is located behind the connection line of the two rear vibration contact positions of the two longitudinal beams 4, and the third cross beam 3 adopts a back-to-back structure with greater stiffness and strength (see Figure 2 and Figure 3 ).

[0004] However, through a large number of cab vibration durability tests, the R & D personnel found that the double-layer beam structure of the longitudinal beam 4, the circular tube beam form of the second cross beam 2, and the back-to-back structure form of the third cross beam 3 in the traditional special short frame result in too large torsional rigidity of the special short frame, reducing the test accuracy of the vibration durability test; at the same time, the castings connected to both ends of the second cross beam 2 are prone to cracking; the installation position of the circular tube beam, that is, near the middle position of the transverse connection line of the vibration contact positions of the two longitudinal beams 4 where the circular tube beam is arranged, results in insufficient lateral bending stiffness of the special short frame at the loading positions of the two lateral actuators. Through experimental research, it is found that the test accuracy of the vibration durability test is also reduced. Summary of the Invention

[0005] Aiming at the defects existing in the prior art, the purpose of this application is to provide a special short frame and a test bench for cab vibration durability testing. By adjusting the longitudinal beam and the first cross beam to be consistent with the real vehicle, changing the positions and structures of the second cross beam and the third cross beam, reducing its own torsional stiffness and increasing its own lateral bending stiffness, the test accuracy of the cab vibration durability test is improved.

[0006] To achieve the above object, the technical solution adopted is: a special short frame for the cab vibration durability test. The special short frame includes two longitudinal beams, a first cross beam, a second cross beam, and a third cross beam. The longitudinal beams and the first cross beam are adjusted to be the same as those of the actual vehicle, and both ends of the first cross beam are connected to the two longitudinal beams by the same connection method as the front cross beam of the actual vehicle. The second cross beam and the third cross beam are both customized cross beams with adjustable lengths. Both ends of the customized cross beam can swing up and down relative to the two longitudinal beams by a certain angle. The center line of the second cross beam coincides with the connecting line of the front vibration contact position, and the center line of the third cross beam coincides with the connecting line of the rear vibration contact position.

[0007] Based on the above technical solution, the customized cross beam includes:

[0008] A double-headed threaded round tube;

[0009] Two shaft end connection plates respectively used to connect the two longitudinal beams;

[0010] Two transition connectors. One end of each transition connector is threadedly connected to one end of the double-headed threaded round tube, and the other end can be swing-mounted up and down at the center of the shaft end connection plate.

[0011] Based on the above technical solution, the transition connector includes:

[0012] A joint axis support fixed to the inner side surface of the shaft end connection plate;

[0013] A joint axis straddling and mounted on the inner end surface of the joint axis support;

[0014] A rod end spherical plain bearing. Its bearing body is fixedly sleeved on the joint axis, and its rod body is threadedly connected to one end of the double-headed threaded round tube.

[0015] Based on the above technical solution, the transition connector further includes two joint axis cover plates, which are respectively fixed to the joint axis support by long bolts and press against both ends of the joint axis.

[0016] Based on the above technical solution, the transition connector further includes a locking nut, which is connected to the rod end and abuts against the side end surface of the double-headed threaded round tube.

[0017] Based on the above technical solution, the special short frame further includes local reinforcement plates. The shaft end connection plates at each end of the customized cross beam are connected to the longitudinal beams through the local reinforcement plates.

[0018] This application also discloses a test bench, including:

[0019] The above special short frame;

[0020] Four L-shaped plate fixtures are respectively arranged at four vibration contact positions of two longitudinal beams; the horizontal plate of the L-shaped plate fixture is attached to the bottom surface of the longitudinal beam, and the vertical plate of the L-shaped plate fixture is attached to the outer side surface of the longitudinal beam;

[0021] Seven actuators, including four vertical actuators, two lateral actuators and one longitudinal actuator. The four vertical actuators are respectively vertically abutted and connected to the horizontal plates of the four L-shaped plate fixtures from bottom to top. The two lateral actuators are respectively vertically abutted and connected to the vertical plates of the two L-shaped plate fixtures of the same longitudinal beam from the side. One longitudinal actuator is vertically abutted along the longitudinal direction to the auxiliary connecting plate connecting the two longitudinal beams.

[0022] On the basis of the above technical solution, the customized cross beam includes a double-headed threaded round tube, two transition connectors and two shaft end connecting plates respectively used for connecting two longitudinal beams. One end of each transition connector is threadedly connected to one end of the double-headed threaded round tube, and the other end can be swing-mounted up and down at the center of the shaft end connecting plate;

[0023] The transition connector includes a joint shaft support, a joint shaft and a rod end joint bearing. The joint shaft support is fixed to the inner side surface of the shaft end connecting plate; the joint shaft is straddle-mounted on the inner end surface of the joint shaft support; the bearing body of the rod end joint bearing is fixedly sleeved on the joint shaft, and its rod body is threadedly connected to one end of the double-headed threaded round tube.

[0024] On the basis of the above technical solution, the transition connector further includes two joint shaft cover plates, and the two joint shaft cover plates are respectively fixed to the joint shaft support by long bolts and press the two ends of the joint shaft; the transition connector further includes a locking nut, and the locking nut is connected to the rod end and abuts against the side end surface of the double-headed threaded round tube.

[0025] On the basis of the above technical solution, the special short vehicle frame further includes a local reinforcement plate, and the shaft end connecting plate at each end of the customized cross beam is connected to the longitudinal beam through the local reinforcement plate.

[0026] The beneficial effects brought by the technical solution provided by this application include:

[0027] 1. The special short frame of the present application adjusts the longitudinal beam and the first cross beam to be consistent with the actual vehicle, changes the positions and structures of the second cross beam and the third cross beam, makes the center line of the second cross beam coincide with the connecting line of the front vibration contact positions, and makes the center line of the third cross beam coincide with the connecting line of the rear vibration contact positions; both the second cross beam and the third cross beam adopt customized cross beams, and both ends of the customized cross beam can swing up and down relative to the two longitudinal beams; the specially adjusted special short frame meets the requirements of moderate torsional stiffness and large side bending stiffness during the test, achieving the purpose of improving the accuracy of the cab vibration durability test; the special short frame of the present application can make the road spectrum signal leave a power spectrum with a wider bandwidth after band-pass filtering processing, and finally converge after iteration, reducing the iteration error between the driving signal and the original road spectrum signal, improving the iteration accuracy, that is, improving the test accuracy of the vibration durability test. At the same time, the length of the customized cross beam is adjustable, which can adapt to different inner widths between the two longitudinal beams of the actual vehicle frame, and has a wider application range.

[0028] 2. The customized cross beam of the present application is ingeniously designed. By enabling the end of the shaft end connecting plate and the double-headed threaded round tube to swing up and down relative to each other by a certain angle, the torsional freedom of the frame is released by the up and down swinging characteristics, not only reducing the overall torsional stiffness of the special short frame, but also effectively protecting the structures at both ends of the customized cross beam, making the corresponding connecting parts at both ends of the customized cross beam not easily crack.

[0029] 3. The customized cross beam of the present application is ingeniously designed. During the actual use of the customized cross beam, the matching length of the double-headed threaded round tube and the rod body of the rod end spherical plain bearing can be changed through the shaft end connecting plate, which can adapt to different inner widths between the two longitudinal beams of the actual vehicle frame and has a wider application range; at the same time, after adjusting the length, it is locked with a lock nut, which is stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 is the top view of the traditional special short frame;

[0032] Figure 2 is Figure 1 the structural schematic diagram of the third cross beam in

[0033] Figure 3 is Figure 2 the bottom view of

[0034] Figure 4 is the top view of the special short frame provided by the embodiment of the present application;

[0035] Figure 5 Structural schematic diagram of the customized crossbeam provided by the embodiment of the present application;

[0036] Figure 6 Exploded view of one end of the customized crossbeam provided by the embodiment of the present application;

[0037] Figure 7 Schematic diagram of the local reinforcement plate provided by the embodiment of the present application;

[0038] Figure 8 Power spectrum obtained by band-pass filtering of the road spectrum signal for the vibration durability test of the traditional special short frame;

[0039] Figure 9 RMS error curve graph of the drive signal formed by iteration and the original road spectrum signal for the vibration durability test of the traditional special short frame;

[0040] Figure 10 Power spectrum obtained by band-pass filtering of the road spectrum signal for the vibration durability test of the special short frame of the present application;

[0041] Figure 11 RMS error curve graph of the drive signal formed by iteration and the original road spectrum signal for the vibration durability test of the special short frame of the present application;

[0042] Reference numerals:

[0043] 1, First crossbeam; 2, Second crossbeam; 3, Third crossbeam; 4, Longitudinal beam; 5, Frame front large casting support; 10, Front vibration contact position connecting line; 11, Rear vibration contact position connecting line; 20, Customized crossbeam; 201, Shaft end connecting plate; 202, Joint shaft cover plate; 203, Long bolt; 204, Joint shaft support; 205, Joint shaft; 206, Rod end joint bearing; 207, Locking nut; 208, Double-headed threaded round tube; 21, Local reinforcement plate. Detailed implementation manners

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] As Figures 4 to 11As shown in the figure, the present application also discloses a special short frame for the cab vibration durability test. The special short frame includes two longitudinal beams 4, a first cross beam 1, a second cross beam 2, and a third cross beam 3. The two ends of the three cross beams are respectively vertically connected to the two longitudinal beams 4.

[0046] The longitudinal beam 4 is adjusted to be the same as that of the actual vehicle, reducing the torsional stiffness of the special short frame. Specifically, the cross-sectional shape and thickness dimension of the longitudinal beam 4 are adjusted to be the same as those of the longitudinal beam of the actual vehicle, and the length is relatively shorter than that of the actual vehicle. The longitudinal beam of the actual vehicle adopts a single-layer beam structure, and the double-layer beam structure of the longitudinal beam of the traditional special short frame is adjusted to be the same as that of the actual vehicle, reducing the torsional stiffness of the special short frame.

[0047] Similarly, the first cross beam 1 is the same as the front cross beam of the actual vehicle, and the two ends of the first cross beam 1 are connected to the two longitudinal beams 4 in the same connection manner as the front cross beam of the actual vehicle. Specifically, both ends of the first cross beam 1 are connected to the longitudinal beam 4 through the large casting bracket 5 at the front end of the frame.

[0048] Starting from the structure of the longitudinal beam 4 and the first cross beam 1, the torsional stiffness of the special short frame is reduced.

[0049] Both the second cross beam 2 and the third cross beam 3 adopt customized cross beams 20 with adjustable lengths. Both ends of the customized cross beam 20 can swing up and down relative to the two longitudinal beams 4 by a certain angle. The characteristic that both ends of the customized cross beam 20 can swing up and down relative to the two longitudinal beams 4 releases the torsional freedom and further reduces the torsional stiffness of the special short frame. Specifically, a certain angle refers to the positive and negative angles set in advance.

[0050] The center line of the second cross beam 2 coincides with the front vibration contact position connection line 10, and the center line of the third cross beam 3 coincides with the rear vibration contact position connection line 11. The installation positions of the second cross beam 2 and the third cross beam 3 reduce the torsional stiffness of the special short frame and increase the side bending stiffness of the special short frame.

[0051] The special short frame of the present application adjusts the longitudinal beam and the first cross beam to be the same as those of the actual vehicle, changes the positions and structures of the second cross beam and the third cross beam, reduces its own torsional stiffness and increases its own side bending stiffness, and improves the accuracy of the cab vibration durability test.

[0052] Specifically, torsion specifically refers to the torsion caused to the special short frame when the forces applied by the four vertical actuators during the vibration test are not always the same. The greater the torsional stiffness of the special short frame, the greater the resistance to the torsion caused to the four vertical actuators. The smaller the torsional stiffness of the special short frame, the smaller the resistance to the torsion caused to the four vertical actuators.

[0053] Lateral bending specifically refers to the lateral bending of the special short frame caused by the fact that the forces applied by the two side actuators during the vibration test are not always the same. The greater the lateral bending stiffness of the special short frame, the greater the resistance to this kind of bending. The smaller the lateral bending stiffness of the special short frame, the smaller the resistance to this kind of bending.

[0054] The special short frame of this application has a simple structure. The longitudinal beam and the first cross beam are adjusted to be consistent with the actual vehicle, and the positions and structures of the second cross beam and the third cross beam are adjusted. After the specific adjustment, the special short frame meets the requirements of moderate torsional stiffness and large lateral bending stiffness during the test. When the road spectrum signal of this application is processed by band-pass filtering, a power spectrum with a wider bandwidth is left, and iteration is carried out and finally converges, and an RMS error with a smaller iteration error can be obtained, that is, the driving signal obtained by power spectrum iteration is closer to the original road spectrum signal, improving the test accuracy of the vibration durability test. At the same time, the length of the customized cross beam 20 is adjustable, which can adapt to different inner widths between the two longitudinal beams of the actual vehicle frame, and has a wider application range.

[0055] In one embodiment, the customized cross beam 20 includes a double-headed threaded round tube 208, two shaft end connection plates 201, and two transition connectors. The double-headed threaded round tube 208 is used as the main structure of the customized cross beam 20. The two shaft end connection plates 201 are respectively used to connect the two longitudinal beams 4, and the two transition connectors are used to transitionally connect the shaft end connection plates 201 and the ends of the customized cross beam 20. One end of each transition connector is threadedly connected to one end of the double-headed threaded round tube 208, and the other end can be swingably mounted up and down at the center of the shaft end connection plate 201.

[0056] For the customized cross beam 20 of this application, by enabling the ends of the shaft end connection plate 201 and the double-headed threaded round tube 208 to swing relative to each other up and down by a certain angle, the torsional freedom is released by the up-and-down swing characteristic, reducing the overall torsional stiffness of the special short frame. At the same time, this up-and-down swing characteristic can effectively protect the structures at both ends of the customized cross beam 20, making the corresponding connectors at both ends of the customized cross beam 20 not easily crack.

[0057] Furthermore, the transition connector includes a joint shaft support 204, a joint shaft 205, and a rod end joint bearing 206. The joint shaft support 204 is fixed to the inner side surface of the shaft end connection plate 201. Preferably, the joint shaft support 204 is welded and fixed to the inner side surface of the shaft end connection plate 201.

[0058] The joint axis 205 is installed across the inner end face of the joint axis support 204. The rod end spherical plain bearing 206 includes a bearing body and a rod body. The bearing body is fixedly sleeved on the joint axis 205. Specifically, the inner ring of the bearing body is interference-fitted on the joint axis 205. The rod body is threadedly connected to one end of the double-threaded round tube 208. In actual use, by rotating the rod end spherical plain bearing 206, the matching length between the rod body and the end of the double-threaded round tube 208 can be changed, thereby adjusting the length of the entire customized cross beam.

[0059] Specifically, the joint axis support 204 reserves a space for the bearing body of the rod end spherical plain bearing 206 to rotate.

[0060] Furthermore, the transition connecting piece further includes two joint axis cover plates 202. The two joint axis cover plates 202 are respectively fixed to the joint axis support 204 by long bolts 203 and press against both ends of the joint axis 205.

[0061] Even further, the transition connecting piece further includes a lock nut 207. The lock nut 207 is connected to the rod end and abuts against the side end face of the double-threaded round tube 208.

[0062] In the process of actually using the customized cross beam 20, the matching length between the double-threaded round tube 208 and the rod body of the rod end spherical plain bearing 206 can be changed through the shaft end connecting plate 201, which can adapt to different inner widths between the two longitudinal beams of the vehicle frame, and has a wider application range. At the same time, after adjusting the length, it is locked with the lock nut 207. The customized cross beam 20 can rotate a certain angle to release the torsional freedom and reduce the torsional stiffness.

[0063] Furthermore, the special short vehicle frame further includes local reinforcement plates 21. The shaft end connecting plates 201 at each end of the customized cross beam 20 are respectively connected to the longitudinal beam 4 through the local reinforcement plates 21.

[0064] Preferably, the local reinforcement plate is processed from a 4-mm-thick steel plate with a thickness of 300 mm. Specifically, the cross-sectional dimensions of the longitudinal beam 4 are the same as those of the local reinforcement plate.

[0065] The local reinforcement plate 21 increases the structural strength of the connection part and further prevents the connection part from cracking.

[0066] In a specific embodiment, using the same 7-channel road spectrum signals (one road spectrum signal corresponds to one actuator) as the initial conditions, a comparative test is carried out on the traditional special short vehicle frame and the special short vehicle frame of the present application.

[0067] In the experiment, each road spectrum signal first undergoes band-pass filtering by the controller of the test bench corresponding to the special short frame to obtain the power spectrum (the bandwidth of the power spectrum is related to the special short frame), and the power spectrum then undergoes multiple rounds of iteration (this iteration process is related to the special short frame) to form the drive signal of the test bench, and the RMS (root mean square) error curve between the drive signal and the original road spectrum signal is obtained. The results are as shown in Figure 8 , Figure 9 , Figure 10 and Figure 11 as follows:

[0068] As can be seen from the figure, for the results obtained with the traditional special short frame, the bandwidth of the power spectrum obtained after the road spectrum signal undergoes band-pass filtering (the power spectrum obtained after one of the road spectrum signals undergoes band-pass filtering is shown in Figure 8 ) is 0.5 - 30 Hz. The RMS (root mean square) error curve graph of the drive signal and the original road spectrum signal obtained after 14 rounds of iteration of the power spectrum (the RMS error of 7 channels is shown in Figure 9 ). It can be seen from Figure 9 that the RMS (root mean square) error of the 7 road spectrum signals of the 7 actuators is approximately 5 - 12% after the final iteration.

[0069] For the results obtained with the special short frame of the present application, the bandwidth of the power spectrum obtained after the road spectrum signal undergoes band-pass filtering (the power spectrum obtained after one of the road spectrum signals undergoes band-pass filtering is shown in Figure 10 , and this road spectrum signal is the same as Figure 8 ) is 0.5 - 40 Hz. The RMS error curve graph of the drive signal and the original road spectrum signal obtained after multiple rounds of iteration of the power spectrum (the RMS error of 7 channels is shown in Figure 11 ). It can be seen from Figure 11 that the RMS (root mean square) error of the 7 road spectrum signals of the 7 actuators is approximately 3 - 8% after the final iteration.

[0070] Comparing the two, the frequency width range of the power spectrum of the special short frame of the present application is wider, that is, the bandwidth is wider. The power spectrum bandwidth is increased by 10 Hz compared to the traditional special short frame, and the RMS (root mean square) error after the final iteration is smaller, with the accuracy improved by approximately 37%. Obviously, the special short frame of the present application reduces the iteration error, improves the iteration accuracy, and improves the test accuracy of the vibration durability test.

[0071] The special short frame of the present application adjusts the longitudinal beam and the first cross beam to be consistent with the actual vehicle, changes the positions and structures of the second cross beam and the third cross beam, makes the center line of the second cross beam coincide with the front vibration contact position connection line 10, and makes the center line of the third cross beam 3 coincide with the rear vibration contact position connection line 11; both the second cross beam and the third cross beam adopt customized cross beams 20, and both ends of the customized cross beam 20 can swing up and down relative to the two longitudinal beams 4;

[0072] The specially designed short frame after specific adjustment meets the requirements of moderate torsional stiffness and large side bending stiffness during the test process, achieving the purpose of improving the accuracy of the cab vibration durability test; the specially designed short frame of the present application can leave a power spectrum with a wider bandwidth when the road spectrum signal is processed by band-pass filtering, and finally converge after iteration, reducing the iteration error and improving the iteration accuracy, that is, improving the test accuracy of the vibration durability test. At the same time, the length of the customized cross beam 20 is adjustable, which can adapt to different inner widths between the two longitudinal beams of the actual vehicle frame, and has a wider application range.

[0073] The customized cross beam 20 of the present application is ingeniously designed. By enabling the end parts of the shaft end connecting plate 201 and the double-headed threaded round tube 208 to swing relatively up and down by a certain angle, the torsional freedom of the frame is released by using the up and down swinging characteristics. This not only reduces the overall torsional stiffness of the specially designed short frame, but also effectively protects the structures at both ends of the customized cross beam 20, making it not easy for the corresponding connecting parts at both ends of the customized cross beam 20 to crack.

[0074] The customized cross beam 20 of the present application is ingeniously designed. During the actual use of the customized cross beam 20, the matching length of the double-headed threaded round tube 208 and the rod body of the rod end spherical plain bearing 206 can be changed through the shaft end connecting plate 201, which can adapt to different inner widths between the two longitudinal beams of the actual vehicle frame and has a wider application range; at the same time, after adjusting the length, it is locked with the lock nut 207, which is stable and reliable.

[0075] The present application also discloses an embodiment of a test bench. The test bench includes the above-mentioned specially designed short frame, four L-shaped plate fixtures, and seven actuators. The four L-shaped plate fixtures are respectively arranged at four vibration contact positions of the two longitudinal beams; the horizontal plate of the L-shaped plate fixture fits on the bottom surface of the longitudinal beam, and the vertical plate of the L-shaped plate fixture fits on the outer side surface of the longitudinal beam;

[0076] The seven actuators include four vertical actuators, two lateral actuators, and one longitudinal actuator. The four vertical actuators vertically abut and connect to the horizontal plates of the four L-shaped plate fixtures from bottom to top. The two lateral actuators vertically abut and connect to the vertical plates of the two L-shaped plate fixtures on the same longitudinal beam 4 from the side. One longitudinal actuator vertically abuts against the auxiliary connecting plate along the longitudinal direction, and both ends of the auxiliary connecting plate are respectively connected to the two longitudinal beams 4.

[0077] Regarding the test bench, in one embodiment, the customized cross beam 20 includes a double-headed threaded round tube 208, two shaft end connection plates 201, and two transition connectors. The double-headed threaded round tube 208 serves as the main structure of the customized cross beam 20. The two shaft end connection plates 201 are respectively used to connect two longitudinal beams 4, and the two transition connectors are used to transitionally connect the shaft end connection plates 201 and the ends of the customized cross beam 20. One end of each transition connector is threadedly connected to one end of the double-headed threaded round tube 208, and the other end is swingably mounted at the center of the shaft end connection plate 201 in the up and down direction.

[0078] For the test bench of the present application, by enabling the ends of the shaft end connection plate 201 and the double-headed threaded round tube 208 to swing relatively up and down by a certain angle, using the up and down swing characteristics, the torsional freedom is released, and the torsional stiffness of the overall special short vehicle frame is reduced. At the same time, this up and down swing characteristic can effectively protect the structures at both ends of the customized cross beam 20, making it not easy for the corresponding connectors at both ends of the customized cross beam 20 to crack.

[0079] Regarding the test bench, further, the transition connector includes a joint shaft support 204, a joint shaft 205, and a rod end joint bearing 206. The joint shaft support 204 is fixed to the inner side surface of the shaft end connection plate 201. Preferably, the joint shaft support 204 is fixedly welded to the inner side surface of the shaft end connection plate 201.

[0080] The joint shaft 205 is cross-mounted on the inner end surface of the joint shaft support 204. The rod end joint bearing 206 includes a bearing body and a rod body. The bearing body is fixedly sleeved on the joint shaft 205. Specifically, the inner ring of the bearing body is press-fitted on the joint shaft 205. The rod body is threadedly connected to one end of the double-headed threaded round tube 208. In actual use, by rotating the rod end joint bearing 206, the matching length between the rod body and the end of the double-headed threaded round tube 208 can be changed, thereby adjusting the length of the entire customized cross beam. Specifically, the joint shaft support 204 reserves a space that can accommodate the rotation of the bearing body of the rod end joint bearing 206.

[0081] Regarding the test bench, further, the transition connector further includes two joint shaft cover plates 202. The two joint shaft cover plates 202 are respectively fixed to the joint shaft support 204 by long bolts 203 and press against both ends of the joint shaft 205.

[0082] Regarding the test bench, even further, the transition connector further includes a locking nut 207. The locking nut 207 is connected to the rod end and abuts against the side end surface of the double-headed threaded round tube 208.

[0083] Regarding the test bench, during the actual use of the customized crossbeam 20, the matching length of the double-threaded round tube 208 and the rod body of the rod-end spherical plain bearing 206 can be changed through the shaft-end connecting plate 201, which can adapt to different inner widths between the two longitudinal beams of the real vehicle frame, and has a wider application range. At the same time, after adjusting the length, it is locked with the lock nut 207. The customized crossbeam 20 can rotate a certain angle to release the torsional freedom and reduce the torsional stiffness.

[0084] Regarding the test bench, further, the special short frame also includes a local reinforcement plate 21. The shaft-end connecting plate 201 at each end of the customized crossbeam 20 is connected to the longitudinal beam 4 through the local reinforcement plate 21. Preferably, the local reinforcement plate is processed from a 4-mm-thick steel plate with a thickness of 300 mm. Specifically, the cross-sectional dimensions of the longitudinal beam 4 are the same as those of the local reinforcement plate. The local reinforcement plate 21 increases the structural strength of the connection part and further prevents the connection part from cracking.

[0085] In the special short frame of this application, by adjusting the longitudinal beam and the first crossbeam to be consistent with the real vehicle, changing the positions and structures of the second crossbeam and the third crossbeam, the center line of the second crossbeam coincides with the front vibration contact position connection line 10, and the center line of the third crossbeam 3 coincides with the rear vibration contact position connection line 11. Both the second crossbeam and the third crossbeam adopt the customized crossbeam 20, and both ends of the customized crossbeam 20 can swing up and down relative to the two longitudinal beams 4.

[0086] The special short frame after specific adjustment meets the requirements of moderate torsional stiffness and large side-bending stiffness during the test process, achieving the purpose of improving the accuracy of the cab vibration durability test. The special short frame of this application can leave a wider-bandwidth power spectrum during the band-pass filtering process of the road spectrum signal, and finally converge after iteration, reducing the iteration error between the driving signal and the original road spectrum signal, improving the iteration accuracy, that is, improving the test accuracy of the vibration durability test. At the same time, the length of the customized crossbeam 20 is adjustable, which can adapt to different inner widths between the two longitudinal beams of the real vehicle frame, and has a wider application range.

[0087] In the description of this application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0088] It should be noted that in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0089] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A special short frame for cab vibration durability test, the special short frame comprising two longitudinal beams (4), a first cross beam (1), a second cross beam (2) and a third cross beam (3). It is characterized in that; The longitudinal beam (4) and the first cross beam (1) are both adjusted to be the same as those of the actual vehicle, and the two ends of the first cross beam (1) are connected to the two longitudinal beams (4) by the same connection method as the front cross beam of the actual vehicle; The second cross beam (2) and the third cross beam (3) both adopt customized cross beams (20) with adjustable lengths; both ends of the customized cross beam (20) can swing up and down relative to the two longitudinal beams (4) by a certain angle; the center line of the second cross beam (2) coincides with the front vibration contact position connecting line (10), and the center line of the third cross beam (3) coincides with the rear vibration contact position connecting line (11); The customized cross beam (20) includes: Double-headed threaded round tube (208); Two shaft end connecting plates (201) respectively used for connecting the two longitudinal beams (4); Two transition connectors, one end of each transition connector is threadedly connected to one end of the double-headed threaded round tube (208), and the other end can be swing-mounted up and down at the center of the shaft end connecting plate (201); The transition connector includes: Joint axis support (204), which is fixed to the inner side surface of the shaft end connecting plate (201); Joint axis (205), which is installed across the inner end surface of the joint axis support (204); Rod end joint bearing (206), whose bearing body is fixedly sleeved on the joint axis (205), and whose rod body is threadedly connected to one end of the double-headed threaded round tube (208).

2. The special short vehicle frame for the cab vibration durability test according to claim 1, wherein The transition connector also includes two joint axis cover plates (202), and the two joint axis cover plates (202) are respectively fixed to the joint axis support (204) by long bolts (203) and press both ends of the joint axis (205).

3. The special short vehicle frame for cab vibration durability test according to claim 1, characterized in that, The transition connector also includes a locking nut (207), and the locking nut (207) is connected to the rod end and abuts against the side end surface of the double-headed threaded round tube (208).

4. A special short frame for cab vibration durability test according to claim 1, characterized in that: The special short vehicle frame also includes a local reinforcement plate (21), and the shaft end connecting plate (201) at each end of the customized cross beam (20) is connected to the longitudinal beam (4) through the local reinforcement plate (21).

5. A test bench, characterized in that, It includes: The special short vehicle frame as described in claim 1; Four L-shaped plate clamps are respectively arranged at the four vibration contact positions of the two longitudinal beams; the horizontal plate of the L-shaped plate clamp fits against the bottom surface of the longitudinal beam, and the vertical plate of the L-shaped plate clamp fits against the outer side surface of the longitudinal beam; Seven actuators, including four vertical actuators, two lateral actuators and one longitudinal actuator, the four vertical actuators respectively vertically abut and connect to the horizontal plates of the four L-shaped plate clamps from bottom to top, the two lateral actuators respectively vertically abut and connect to the vertical plates of the two L-shaped plate clamps on the same longitudinal beam (4) from the side, and one longitudinal actuator vertically abuts against the auxiliary connecting plate connecting the two longitudinal beams (4) along the longitudinal direction.

6. A test bench according to claim 5, characterized in that: The customized cross beam (20) includes a double-headed threaded round tube (208), two transition connectors and two shaft end connecting plates (201) respectively used for connecting the two longitudinal beams (4), one end of each transition connector is threadedly connected to one end of the double-headed threaded round tube (208), and the other end can be swing-mounted up and down at the center of the shaft end connecting plate (201); The transition connecting piece includes a joint axis support (204), a joint axis (205) and a rod end joint bearing (206). The joint axis support (204) is fixed to the inner side surface of the shaft end connecting plate (201); the joint axis (205) is installed across the inner end surface of the joint axis support (204); the bearing body of the rod end joint bearing (206) is fixedly sleeved on the joint axis (205), and its rod body is threadedly connected to one end of the double-headed threaded round tube (208).

7. The test bench according to claim 6, characterized in that: The transition connecting piece further includes two joint axis cover plates (202). The two joint axis cover plates (202) are respectively fixed to the joint axis support (204) by long bolts (203) and press against both ends of the joint axis (205); the transition connecting piece further includes a locking nut (207). The locking nut (207) is connected to the rod end and abuts against the side end surface of the double-headed threaded round tube (208).

8. A test bench as claimed in claim 6, characterized in that: The special short vehicle frame further includes a local reinforcing plate (21). The shaft end connecting plates (201) at each end of the customized cross beam (20) are connected to the longitudinal beam (4) through the local reinforcing plates (21).

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