A test bench for abnormal noise under composite degree of freedom excitation

Abstract

This invention provides a test bench for abnormal noise under combined degree-of-freedom excitation, comprising a base, a support frame, a stage, a first limiting member, a second limiting member, and a driving mechanism. The support frame has a first mounting part, the bottom of the stage has a second mounting part and two driving connection parts, and one side of the stage has a third mounting part. The first limiting member includes a rod and two first elastic components, with the first and second mounting parts connected to the two ends of the rod respectively through the first elastic components. The second limiting member includes an extension arm and a mounting seat, the mounting seat including a second elastic component, and the two ends of the extension arm connected to the second elastic component and the third mounting part respectively. The driving mechanism includes two driving ends, each connected to a driving connection part. This invention utilizes the first and second limiting members to support, limit, and guide the stage, achieving combined degree-of-freedom excitation only through the excitation force in the z-direction, resulting in convenient operation and good testing performance.

Description

Technical Field

[0001] This invention relates to the field of vehicle testing technology, and more specifically to a test bench for abnormal noises with composite degrees of freedom excitation. Background Technology

[0002] In recent years, abnormal noises in automobiles have received increasing attention. As we all know, automobiles are assembled from numerous parts, and abnormal noises from these parts are a significant component of overall vehicle noise. Nowadays, major parts suppliers and automobile manufacturers pay close attention to abnormal noises from parts, typically using testing methods to determine if any parts are making unusual noises.

[0003] Currently, when simulating the interaction between vehicles and actual road surfaces, vibration test benches for components are mostly equipped with drive mechanisms that can provide excitation forces in the X, Y, and Z directions, causing the tested components to vibrate sequentially in the front-back, left-right, and vertical directions. However, the motion patterns of a car during driving are varied, and the vibration direction of the components is not always unidirectional along the X, Y, and Z directions. This makes it difficult for the results obtained from single-degree-of-freedom tests of the components to match the actual scenario well. Therefore, technicians often need to verify the X, Y, and Z directions multiple times to achieve a better fit. This testing method takes a lot of time and has insufficient fidelity to the real scenario. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a composite degree-of-freedom excitation noise test bench, which can simulate vehicle vibration in composite degree-of-freedom directions, thereby solving the problem of insufficient real-world scene reproduction in single-degree-of-freedom testing in existing technologies and improving testing efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A composite degree-of-freedom excitation noise test bench, characterized in that it includes a base, a support frame, a stage, a first limiting member, a second limiting member, and a driving mechanism; the support frame is provided with a first mounting part, the bottom of the stage in the z-direction is provided with a second mounting part and two driving connection parts arranged in the y-direction, and a third mounting part is provided on one side of the stage in the x-direction; the first limiting member includes a rod arranged in the y-direction and two first elastic components located at both ends of the rod, the first mounting part and the second mounting part are respectively connected to the two ends of the rod through the first elastic components; the second limiting member includes an extension arm and a mounting seat, the mounting seat includes a base fixedly connected to the base and a second elastic component disposed on the upper side of the base, the two ends of the extension arm respectively form a lower connection part that can connect to the second elastic component and an upper connection part that can connect to the third mounting part, the center point of the upper connection part and the center point of the lower connection part are on the same xz plane; the driving mechanism includes two driving ends arranged in the y-direction that can vibrate in the z-direction, each driving end being connected to a driving connection part.

[0007] Furthermore, the first elastic component includes a first positioning member and a first elastic connecting member. The first positioning member is fixedly connected to the first mounting part / second mounting part, and the first positioning member forms an elastic abutment with the end of the rod body through the first elastic connecting member.

[0008] Furthermore, the rod is capable of rotating about the first elastic connector in a plane parallel to the y-direction.

[0009] Furthermore, the first limiting member also includes two adjusting components disposed at both ends of the rod body. The adjusting components include a connecting screw and an adjusting block. The connecting screw is coaxially disposed and fixedly connected to the rod body. The adjusting block has a connecting screw hole in the middle that can be movably engaged with the connecting screw. The first elastic block elastically abuts against the adjusting block.

[0010] Furthermore, the first limiting member also includes an inner end encapsulation plate, an outer end encapsulation plate, and an encapsulation sleeve. The first positioning member also includes a through-hole disposed in the middle. The inner end encapsulation plate is fixedly connected to the end of the rod. The outer end encapsulation plate has a through-hole in the middle for the through-hole to pass through. The inner end encapsulation plate and the outer end encapsulation plate are provided with several encapsulation connection holes near their edges. The two ends of the encapsulation sleeve are fixedly connected to the inner end encapsulation plate and the outer end encapsulation plate, respectively.

[0011] Furthermore, the second elastic component includes a second positioning member and a second elastic connecting member. The second positioning member is fixedly connected to the base, and the second positioning member forms an elastic abutment with the lower connecting portion through the second elastic connecting member.

[0012] Furthermore, the extension arm is capable of rotating about the second positioning member in a plane parallel to the z-direction.

[0013] Furthermore, the extension arm includes a main connecting arm and two symmetrically arranged branch connecting arms. The first end of the main connecting arm is connected to the second elastic component, and the second end extends along an xz plane toward the extension stage. The branch connecting arms are connected to the second end of the main connecting arm and extend toward the stage. An angle is formed between the two branch connecting arms. The third mounting part includes two mounting areas corresponding to the branch connecting arms.

[0014] Furthermore, the support frame includes a support column connected to the base, a support base plate connected to the upper end of the support column, and a plurality of support airbags arranged along the y-direction on the upper side of the support base plate. The first limiting member is located near the x-direction side where the third mounting part is provided, and the support airbags are located near the other x-direction side.

[0015] In summary, the following beneficial effects can be achieved by applying this invention:

[0016] 1. This invention utilizes a first limiting member and a second limiting member to support and limit the platform. The first and second limiting members are connected by a first elastic component and a second elastic component, which limit and guide the movement of the platform. When the two driving ends vibrate in the same direction, the platform's motion is a rotation centered on the second elastic component in the xz plane. This motion is formed by the combination of x-axis and z-axis motion. When the two driving ends vibrate in opposite directions, the platform's motion is a rotation centered on the first elastic component in the yz plane. This motion is formed by the combination of y-axis and z-axis motion, thereby achieving composite degree of freedom excitation of the platform and better simulating actual road conditions.

[0017] 2. The first and second elastic components of this invention, while providing a limiting function, allow the stage to vibrate in multiple degrees of freedom. The first elastic component does not hinder pitch vibration, and the second elastic component does not hinder tilt vibration. No parts need to be disassembled during the switching process of pitch and tilt tests, making the operation convenient and efficient.

[0018] 3. In some embodiments, the present invention is further provided with a support airbag, which can assist in bearing weight, and the first limiting member and the support airbag can be respectively positioned close to and far from the third mounting part, thereby reducing the lever arm length between the first limiting member and the second elastic member and reducing the influence of the first limiting member on pitch vibration. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the abnormal noise test bench with composite degree of freedom excitation in the embodiment;

[0020] Figure 2 for Figure 1 Side view;

[0021] Figure 3 for Figure 1 Rear view;

[0022] Figure 4 for Figure 1 A schematic diagram of the structure of the first limiting component;

[0023] Figure 5 for Figure 1 Schematic diagram of the structure of the second limiting component;

[0024] Figure 6 This is a schematic diagram of the structure of the second limiting member in another embodiment;

[0025] In the picture:

[0026] 1-Base;

[0027] 2-Support frame, 21-Support column, 22-Support base plate, 23-First mounting part, 24-Support airbag;

[0028] 3-Stage, 31-Second mounting part, 32-Drive connection part, 33-Third mounting part;

[0029] 4-First limiting component, 41-Rod body, 42-First elastic component, 43-Connecting screw, 44-Adjusting block, 45-Inner end encapsulation plate, 46-Outer end encapsulation plate, 47-Encapsulation sleeve;

[0030] 5-Second limiting member, 51-Extension arm, 511-Main connecting arm, 512-Branch connecting arm, 513-Lower connecting part, 514-Upper connecting part, 52-Mounting base, 521-Base, 522-Second elastic member;

[0031] 6-Drive mechanism, 61-Drive end, 62-Drive connecting rod. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example

[0033] Reference Figures 1-6This embodiment provides a noise test bench with composite degree of freedom excitation. This test bench can control the drive to induce rotational vibration of the tested component in the xz plane or in the yz plane, thereby achieving composite degree of freedom excitation of the component. This better simulates actual road conditions and facilitates the study of the formation mechanism of abnormal noise. Specifically, the noise test bench includes the following structure:

[0034] The base 1 is fixedly connected to the foundation during use and provides a stable mounting base for other structures. In some embodiments, the base may include a large plate unit, and other structures of the noise test bench are assembled based on this large plate unit. In other embodiments, the base may also include multiple independent small plate units, each of which provides a mounting base for the corresponding structure. Typically, the plate unit is provided with several fixing holes. Some fixing holes are used to fix the plate unit to the foundation structure, and other fixing holes are used to connect the plate unit to parts of the noise test bench.

[0035] The support frame 2 is fixedly connected to the upper side of the base 1, serving as a support and scaffold. The support frame includes a support column 21 vertically connected to the flat plate unit of the base and a support base plate 22 horizontally arranged in use and connected to the upper end of the support column. A first mounting part 23 is fixedly connected to the upper side of the support base plate. The first mounting part includes a first mounting plate and a second mounting plate connected at right angles to each other. The first mounting plate is attached to the support base plate and is detachably fixed by screws. The second mounting plate is arranged parallel to the xz plane and has a first positioning hole that passes through in the y direction. In this embodiment, the support frame includes two relatively independent support units symmetrically arranged in the xz plane, with a gap between the two support units. Each support unit includes a support base plate and two support columns. The third mounting part is arranged above the support base plate of one of the support units.

[0036] The stage 3 is suspended above the support frame 2 and is used to place and fix the measured parts. The stage includes a stage body. In this embodiment, the stage body is generally rectangular and includes two x-sides, two y-sides, and two z-sides. The z-side bottom surface of the stage body is connected to a second mounting part 31 and two drive connection parts 32. A third mounting part 33 is provided on one x-side of the stage body. The second mounting part includes a third mounting plate and a fourth mounting plate connected at right angles to each other. The third mounting plate is detachably fixed to the z-side bottom surface of the stage body by screws. The fourth mounting plate is parallel to the xz plane and has a second positioning hole that passes through in the y direction. The drive connection part has a drive connection hole that opens in the z direction. The third mounting part has several mounting holes based on the stage body.

[0037] The first limiting member 4 is used to connect the platform 3 and the support frame 2, and plays a supporting and guiding role. The first limiting member includes a rod 41, two first elastic components 42 disposed at both ends of the rod, and an adjusting component disposed between the rod and the first elastic components. The first elastic component includes a first positioning component 421 and a first elastic connecting component 422. At the first end of the rod, the corresponding first positioning component is fixedly connected to the second mounting plate of the first mounting part through a first positioning hole, and the first positioning component forms an elastic abutment with the end of the rod 41 through the first elastic connecting component. At both ends, the corresponding first positioning member is fixedly connected to the fourth mounting plate of the second mounting part through the second positioning hole, and the first positioning member forms an elastic abutment with the end of the rod 41 through the first elastic connector. The elastic abutment structure allows the rod 41 to rotate about the first elastic connector 422 in a plane parallel to the y-direction. The adjusting component includes a connecting screw 43 and an adjusting block 44. The connecting screw 43 is coaxially arranged with the rod 41 and is fixedly connected to the end of the rod. The adjusting block has a connecting screw hole in the middle that can be movably engaged with the connecting screw. In the assembled state, the first side of the first elastic member elastically abuts with the adjusting block through the first elastic block, and is then connected to the rod 41 through the connecting screw 43. The second side is fixedly connected to the second mounting plate or the fourth mounting plate through the inner connecting hole.

[0038] The second limiting member 5 is used to connect the platform 3 and the base 1, and plays a supporting and guiding role; the third limiting member includes an extension arm 51 and a mounting base 52. The mounting base includes a base 521 fixedly connected to the base and a second elastic member 522 disposed on the upper side of the base. The two ends of the extension arm form a lower connecting part 513 and an upper connecting part 514 respectively. The center point of the upper connecting part and the center point of the lower connecting part are on the same xz plane. The lower connecting part can be sleeved and fixed on the outer periphery of the elastic sleeve. The upper connecting part can be detachably fixedly connected to the third mounting part 33 by screws. The second elastic member includes a second positioning member and a second elastic connecting member. The second positioning member is fixedly connected to the base 521, and the second positioning member forms an elastic abutment with the lower connecting part 513 through the second elastic connecting member. The extension arm 51 can rotate about the second positioning member in a plane parallel to the z direction.

[0039] The drive mechanism 6 includes two drive ends 61, which are located on the lower side of the stage and arranged in the y-direction. Each drive end is connected to a power source that can provide excitation force, enabling the drive end to vibrate in the z-direction. The drive end is fixedly connected to the drive connection part 32 in the z-direction via a drive connecting rod 62, so that the z-direction vibration generated by the drive end can act on the stage.

[0040] The working principle of this invention is as follows: In the first working state, the two drive ends are controlled by the power source to vibrate in the same direction. The drive ends provide a z-axis excitation force to the platform, causing the platform to undergo periodic lifting and lowering vibrations. The second limiting member provided in this invention limits one x-axis side of the platform. The second limiting member can rotate around the mounting shaft on any axial section of the mounting shaft using the deformation of the elastic sleeve, but it cannot move independently in the z-axis. Since the center point of the upper connecting part and the center point of the lower connecting part of the extension arm are on the same xz plane, the integrated assembly formed after the platform and the second limiting member are fixedly connected will rotate around the mounting shaft in the xz plane after being subjected to the z-axis excitation force. In the second working state, the two drive ends are controlled by the power source to vibrate asynchronously. The drive ends sequentially provide periodic z-axis excitation forces to both sides of the platform in the y-axis direction, causing both sides of the platform in the y-axis direction to vibrate. The system experiences sequential lifting and lowering vibrations. The first limiting member in this invention provides a limiting effect on the platform. The end of the rod is connected to either the first or second mounting part via a first elastic component. Between the rod and the first mounting part, the rod can rotate in the yz plane around the first elastic component. Between the rod and the platform, the platform can rotate in the yz plane around the first elastic component. Taking a driving scenario as an example, a protrusion is located directly in front of the vehicle. When the front wheels pass over this protrusion, the front wheels lift while the rear wheels remain stationary. At this time, the entire vehicle body experiences pitch vibration with the rear wheels as the fulcrum, which is similar to the first working state of this invention. Taking another driving scenario as an example, a protrusion is located on the right front of the vehicle. When the right wheel passes over this protrusion, the right wheel lifts while the left wheel remains stationary. At this time, the entire vehicle body experiences roll vibration with the left wheel as the fulcrum, which is similar to the second working state of this invention. In summary, this invention can simulate the composite degree of freedom vibration during vehicle operation by providing only a z-axis excitation force, thus improving the abnormal noise detection effect. In principle, under the combined action of the first and second limiting members, the vibration direction of the stage calibrated to its original position should always be along the yz plane when it enters the moment of vibration from rest. After the vibration occurs, if the overall position of the stage rises or falls, it will tend to move along the xz plane under the action of the second limiting member. In this invention, during the tilt test, since the forces provided by the two exciters are opposite, the stage as a whole is not considered to have risen. Therefore, the vibration direction during the test is along the yz plane. However, during the pitch test, the forces provided by the two exciters are in the same direction, and the overall position of the stage will rise or fall. At this time, the vibration direction will be along the xz plane. Therefore, this invention can realize the simulation of the above two composite degrees of freedom.

[0041] However, from an extreme perspective, when the amplitude of vibration is extremely small, the positional movement of the stage can be ignored from a macroscopic point of view, and can be regarded as its motion along the yz plane.

[0042] For the present invention, the aforementioned "the center point of the upper connecting part and the center point of the lower connecting part are on the same xz plane" can be achieved through various embodiments. In the first embodiment, the extension arm is a straight structure extending linearly based on the xz plane. In this case, both ends of the extension arm must be on the same xz plane. However, this connection method results in only one connection point between the extension arm and the stage, leading to insufficient stability during pitch vibration. In the second embodiment, referring to... Figure 5 The extension arm includes a main connecting arm 511 and two branch connecting arms 512. The first end of the main connecting arm has a lower connecting portion 513 and is connected to the mounting base 52, and the second end extends linearly along the xz plane towards the stage. The first end of the branch connecting arm is connected to the main connecting arm, and the second end has an upper connecting portion 514 and is connected to the third mounting portion. The two branch connecting arms form an angle with each other. The two branch connecting arms are symmetrically arranged based on the xz plane where the extension direction of the main connecting arm is located. In this embodiment, although each of the two branch connecting arms has an upper connecting portion, since the two branch connecting arms are symmetrically arranged, the center position of the two upper connecting portions is still in the same xz plane as the lower connecting portion. In this embodiment, since there are two connection points between the extension arm and the stage, the stability during pitch vibration is stronger. In the third embodiment, refer to Figure 6 The structure of the extension arm is the same as that of the first embodiment. The difference is that the second limiting member includes two parallel and symmetrically arranged extension arms. Each of the two extension arms is connected to a mounting base 52. Its function is similar to that of the second embodiment, but the second embodiment is more advantageous in terms of cost and space occupation. In addition, the resistance generated by the second embodiment is smaller than that of the third embodiment during the tilt vibration test.

[0043] In other embodiments of the present invention, the stage body is not limited to a cuboid structure, its z-axis bottom surface is not limited to being parallel to the xy plane, and the third and fourth mounting plates of the second mounting part are not limited to being perpendicular to each other, but it is necessary to ensure that the first / second positioning holes on the second and fourth mounting plates are both y-axis openings to ensure the fixed installation of the first elastic member. The x-axis side of the stage body is not limited to being parallel to the yz plane, as long as the x-axis side can be connected to the upper connecting part of the second limiting member.

[0044] In some other embodiments of the present invention, the support frame 2 further includes a plurality of support airbags 24, the upper end of which is connected to the bottom surface of the stage in the z direction and the lower end of which is connected to the upper surface of the support base plate. The plurality of support airbags are arranged in the y direction. The first limiting member is disposed near the x-direction side of the third mounting part, and the support airbags are disposed near the x-direction side of the stage where the third mounting part is not disposed. The drive connection part is disposed between the support airbags and the first limiting member. In this mounting structure, on the one hand, the support airbags can assist in the support, making the stage more stable and reducing the pressure on the first limiting member. On the other hand, the distance between the first limiting member and the second elastic member is small, and the lever arm length between the first limiting member and the second elastic member is small when the stage performs pitch vibration, thus reducing the resistance to pitch movement.

[0045] It should also be noted that the directional constraints of each structure in this application are described in the initial state when the abnormal noise test bench is assembled and in a non-working state. Since multiple components of the abnormal noise test bench are in motion during operation, it does not satisfy the above directional constraints at all times, but only at a specific position.

[0046] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test bench for abnormal noise under composite degree of freedom excitation, characterized in that: The device includes a base (1), a support frame (2), a platform (3), a first limiting member (4), a second limiting member (5), and a drive mechanism (6). The support frame has a first mounting part (23), the platform has a second mounting part (31) at its z-axis bottom and two drive connection parts (32) arranged in the y-axis, and a third mounting part (33) on one x-axis side of the platform. The first limiting member includes a rod (41) arranged in the y-axis and two first elastic components (42) located at both ends of the rod. The first mounting part and the second mounting part are respectively connected to the two ends of the rod through the first elastic components. The second limiting member includes an extension arm (51) and a mounting base (52). The mounting base includes a base (521) fixedly connected to the base and a second elastic component (522) disposed on the upper side of the base. The two ends of the extension arm respectively form a lower connection part (513) that can connect to the second elastic component and an upper connection part that can connect to the third mounting part. The upper connecting part (514) and the lower connecting part are located on the same xz plane; the driving mechanism includes two driving ends (61) arranged in the y direction that can vibrate in the z direction, each driving end being connected to a driving connecting part; the first elastic component (42) includes a first positioning member and a first elastic connecting member, the first positioning member being fixedly connected to the first mounting part / second mounting part, and the first positioning member forming an elastic abutment with the end of the rod (41) through the first elastic connecting member; the rod (41) is capable of rotating in the yz plane with the first elastic connecting member as the center; the second elastic component includes a second positioning member and a second elastic connecting member, the second positioning member being fixedly connected to the base (521), and the second positioning member forming an elastic abutment with the lower connecting part (513) through the second elastic connecting member; the extension arm (51) is capable of rotating in the xz plane with the second positioning member as the center.

2. The abnormal noise test bench with composite degree of freedom excitation according to claim 1, characterized in that: The first limiting member also includes two adjusting components disposed at both ends of the rod body. The adjusting components include a connecting screw (43) and an adjusting block (44). The connecting screw is coaxially disposed and fixedly connected to the rod body. The adjusting block has a connecting screw hole in the middle that can be movably engaged with the connecting screw. The first elastic block elastically abuts against the adjusting block.

3. The abnormal noise test bench with composite degree of freedom excitation according to claim 1, characterized in that: The first limiting member also includes an inner end encapsulation plate (45), an outer end encapsulation plate (46), and an encapsulation sleeve (47). The first positioning member also includes a through-hole provided in the middle. The inner end encapsulation plate is fixedly connected to the end of the rod. The outer end encapsulation plate has a through-hole in the middle for the through-hole to pass through. The inner end encapsulation plate and the outer end encapsulation plate are provided with several encapsulation connection holes near their edges. The two ends of the encapsulation sleeve are fixedly connected to the inner end encapsulation plate and the outer end encapsulation plate, respectively.

4. The abnormal noise test bench with composite degree of freedom excitation according to claim 1, characterized in that: The extension arm includes a main connecting arm (511) and two symmetrically arranged branch connecting arms (512). The first end of the main connecting arm is connected to the second elastic component, and the second end extends along an xz plane toward the extension stage. The branch connecting arms are connected to the second end of the main connecting arm and extend toward the stage. An angle is formed between the two branch connecting arms. The third mounting part includes two mounting areas corresponding to the branch connecting arms.

5. The abnormal noise test bench with composite degree of freedom excitation according to claim 1, characterized in that: The support frame includes a support column (21) connected to the base, a support base plate (22) connected to the upper end of the support column, and a plurality of support airbags (24) arranged along the y direction on the upper side of the support base plate. The first limiting member is located near the x-direction side where the third mounting part is provided, and the support airbags are located near the other x-direction side.

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