NVH detection device

Abstract

The invention relates to the technical field of mechanical transmission part performance testing, in particular to an NVH detection device. Comprising a detection table; the driving unit is mounted on the detection table and is used for providing rotating power; the screw rod transmission unit comprises a screw rod and a detection nut which can be screwed on the screw rod, and the screw rod is in transmission connection with the output end of the driving unit; the load simulation unit is used for providing a simulation load for the detection nut and comprises a counterweight assembly and a traction mechanism used for converting the gravity of the counterweight assembly into axial tension on the detection nut; and the detection unit comprises a vibration sensor which is used for directly contacting with the detection nut and detecting the vibration of the detection nut. Load simulation is achieved at low cost, detection results are accurate and reliable, the structure is simple, and implementation is easy.

Description

Technical Field

[0001] This invention relates to the field of mechanical transmission component performance testing technology, and in particular to an NVH testing device. Background Technology

[0002] As a core component of precision transmission mechanisms, the noise and vibration levels (NVH performance) of the lead screw and nut assembly during operation are key indicators for measuring its quality and reliability. NVH performance testing requires simulating the loads experienced by the lead screw and nut in actual operation to evaluate its performance under load conditions.

[0003] Existing load simulation methods often employ electric cylinders or servo motors to directly apply force or torque. However, this approach has significant drawbacks: First, the electric cylinder or servo motor system itself generates vibration and electromagnetic noise during operation. This additional vibration and noise is directly transmitted to the lead screw and nut assembly being tested, severely interfering with the purity of the detection signal and leading to distorted test results. Second, high-precision, low-vibration electric cylinder or servo loading systems are very expensive, increasing the overall cost of the testing equipment and hindering the widespread application of this testing technology. Therefore, there is an urgent need for an NVH testing solution that can effectively simulate loads without introducing additional interfering vibrations and is also cost-effective. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings of the prior art and provide an NVH testing device with reasonable structure, low cost and accurate test results.

[0005] In a first aspect, the present invention provides an NVH (Noise, Vibration, and Harshness) detection device, comprising: Testing station; A drive unit, mounted on the detection platform, is used to provide rotational power; A lead screw drive unit includes a lead screw and a detection nut screwable on the lead screw, wherein the lead screw is drively connected to the output end of the drive unit; A load simulation unit is used to provide a simulated load to the detection nut, which includes a counterweight assembly and a traction mechanism for converting the gravity of the counterweight assembly into an axial tensile force on the detection nut. And a detection unit, including a vibration sensor for directly contacting and detecting the vibration of the detection nut.

[0006] In an optional implementation, the load simulation unit includes: The pulley system is installed on the testing platform; A counterweight assembly is disposed below the testing platform, the counterweight assembly including a counterweight frame that can add or remove counterweight blocks; And a pull rope, one end of which is connected to a force-bearing component that moves synchronously with the detection nut, and the other end of which passes around the pulley block and is connected to the counterweight frame; When the detection nut moves under the drive of the lead screw, the counterweight assembly can be raised or lowered through the transmission of the pull rope and the pulley group, so that its gravity acts as a simulated load on the detection nut.

[0007] In an optional embodiment, the load simulation unit further includes at least one vertically arranged guide shaft, the upper end of which is fixed to the bottom of the testing platform, and the counterweight frame is provided with a guide part that slides with the guide shaft to guide the lifting and lowering movement of the counterweight assembly.

[0008] In an optional embodiment, a nut positioning assembly for limiting the rotation of the detection nut is further included, the nut positioning assembly comprising: A nut positioning component has a positioning hole on the side facing the lead screw, and at least one positioning plane is provided on the inner edge of the positioning hole. The detection nut is installed in the positioning hole and its rotation is restricted by the positioning plane. The nut positioning component is further provided with a detection plane that communicates with the positioning hole, and the vibration sensor is disposed on the detection plane and directly contacts the outer wall of the detection nut located in the positioning hole.

[0009] In an optional implementation, it further includes: A linear guide rail is fixedly installed on the testing platform and is arranged parallel to the lead screw; Both the first slider and the second slider are slidably mounted on the linear guide rail; A first connecting seat is mounted on the first slider, and the nut positioning component is fixed to the first connecting seat; The second connecting seat is mounted on the second slider; The load simulation unit is connected to the second connector.

[0010] In an optional embodiment, a pressure sensor connected between the first connecting seat and the second connecting seat is further included to detect the magnitude of the load force borne by the detection nut.

[0011] In an optional embodiment, a buffer is also provided at one end of the linear guide near the lead screw input end for buffering and limiting the first slider sliding in that direction.

[0012] In an optional implementation, the driving unit includes: Electric motor; The motor is mounted on the testing platform via the motor mount. And a coupling connecting the output shaft of the motor and the lead screw.

[0013] In an optional embodiment, the lead screw drive unit further includes a bearing housing fixed to the testing platform and a bearing installed in the bearing housing. The lead screw is connected to the bearing housing through the bearing. The drive unit is located on one side of the bearing housing, and the load simulation unit exerts a pulling force on the testing nut in the opposite direction to the bearing housing.

[0014] In an optional embodiment, the testing platform has a through hole through which the pull rope of the load simulation unit passes.

[0015] Compared with existing technologies, the NVH detection device provided by this invention has the following technical advantages: 1. Low-cost load simulation: The load is simulated by using a purely mechanical structure with counterweight components and traction mechanisms (such as pulley blocks and ropes), completely eliminating the need for expensive electric cylinders or servo loading systems, which significantly reduces the manufacturing cost of the device.

[0016] 2. Accurate and reliable test results: The load provided by the counterweight component is a constant and unfluctuating gravity, and the entire load simulation unit does not generate any vibration or electromagnetic noise during operation. This fundamentally avoids the vibration interference of the load source on the test nut, thereby ensuring that the signal collected by the vibration sensor purely reflects the meshing state and defects between the lead screw and the test nut, greatly improving the accuracy and reliability of NVH testing.

[0017] 3. Simple structure and easy to implement: The overall structure of the device is clear, with a high degree of modularity. The load size can be flexibly adjusted, and operation and maintenance are convenient.

[0018] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure when the lead screw and the detection nut are separated, as provided in an embodiment of the present invention. Figure 2This is a schematic diagram of the overall structure of the detection nut on the lead screw according to an embodiment of the present invention; Figure 3 This is an enlarged view of the lead screw and detection nut provided in an embodiment of the present invention.

[0021] Icons: 1-Detection platform; 2-Base; 3-Motor; 4-Motor mount; 5-Coupling; 6-Bearing mount; 7-Bearing; 8-Screw; 9-Linear guide rail; 10-First slider; 11-First connecting seat; 12-Nut positioning component; 13-Detection plane; 14-Pressure sensor; 15-Second connecting seat; 16-Fixed pulley; 17-Pulley seat; 18-Counterweight assembly; 19-Pull rope; 20-Guide shaft; 21-Counterweight frame; 22-Counterweight block; 23-Lifting ring; 24-Through hole; 25-Buffer; 26-Vibration sensor; 27-Second slider; 28-Detection nut. Detailed Implementation

[0022] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0026] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0027] The specific structure is as follows: Figures 1 to 3 As shown.

[0028] This embodiment provides an NVH testing device, including a testing platform 1, a drive unit, a lead screw transmission unit, a load simulation unit, a testing unit, and related auxiliary positioning and buffering structures.

[0029] Testing platform and base: Testing platform 1 is the installation platform for the entire device, and base 2 is set below it to stably support the entire testing device.

[0030] Drive Unit: The drive unit is mounted on the testing table 1 and provides power to drive the lead screw to rotate. In this embodiment, the drive unit includes a motor 3, a motor mount 4, and a coupling 5. The motor 3 is fixedly mounted on the testing table 1 via the motor mount 4. To further isolate the influence of the motor 3's own vibration on the lead screw transmission unit, a damping block (not shown in the figure, such as a rubber pad) can be placed between the motor 3 and the motor mount 4, or between the motor mount 4 and the testing table 1. The coupling 5 connects the output shaft of the motor 3 to one end of the lead screw 8 and is used to transmit torque. Preferably, the coupling 5 is a magnetic coupling, which uses non-contact magnetic force to transmit torque, effectively isolating the radial and axial vibrations of the motor 3 from being transmitted to the lead screw 8, thus reducing vibration interference from the power input end.

[0031] Screw drive unit: The screw drive unit includes a screw 8 and a detection nut 28. The screw drive unit also includes a bearing housing 6 and a bearing 7 for supporting the screw 8. The bearing housing 6 is fixedly mounted on the detection table 1, and the bearing 7 is installed inside the bearing housing 6. The screw 8 is rotatably supported on the bearing housing 6 via the bearing 7. The motor 3 and the coupling 5 are located on one side of the bearing housing 6. Figure 1 (Left side). Check the fit between nut 28 and lead screw 8.

[0032] Nut positioning assembly: To fix the circumferential position of the test nut 28 during the testing process, ensuring it can only move axially along the lead screw 8 and cannot rotate, a nut positioning assembly is provided. This assembly includes a nut positioning element 12. The nut positioning element 12 has a positioning hole on the side facing the lead screw 8, and at least one positioning plane is machined on the inner edge of the positioning hole. The test nut 28 is installed in this positioning hole, with its outer wall fitting against the positioning plane, thereby restricting its rotation. A testing plane 13 communicating with the positioning hole is also machined on the nut positioning element 12.

[0033] Linear motion guiding mechanism: To provide precise guidance for the axial movement of the detection nut 28, a linear guide rail 9, parallel to the lead screw 8, is fixedly mounted on the detection table 1. A first slider 10 and a second slider 27 are slidably mounted on the linear guide rail 9. A first connecting seat 11 is fixedly mounted on the first slider 10, and a nut positioning member 12 is fixedly mounted on the first connecting seat 11. Therefore, the detection nut 28, the nut positioning member 12, and the first connecting seat 11 form a whole, guided by the first slider 10 to slide along the linear guide rail 9. A second connecting seat 15 is fixedly mounted on the second slider 27.

[0034] Load simulation unit: The load simulation unit is used to apply an adjustable, constant axial load force to the detection nut 28 to simulate its working state. In this embodiment, the load simulation unit includes a traction mechanism consisting of a pulley block, a counterweight assembly 18, and a pull rope 19.

[0035] The pulley system includes pulley seats 17 installed on both sides of the testing table 1 and fixed pulleys 16 installed on the pulley seats 17.

[0036] The counterweight assembly 18 is located below the testing table 1 and includes a counterweight frame 21 and several counterweight blocks 22. The counterweight blocks 22 can be added to or removed from the counterweight frame 21 as needed to change the load. The counterweight frame 21 is equipped with lifting rings 23.

[0037] The traction mechanism is specifically a pull rope 19. One end of the pull rope 19 is connected to the second connecting seat 15 (constituting one embodiment of a "force-bearing component that moves synchronously with the detection nut"), and the other end passes over the fixed pulley 16, passes through the through hole 24 opened on the detection table 1, and is connected to the lifting ring 23 of the counterweight frame 21.

[0038] Furthermore, the load simulation unit also includes a guide mechanism, which includes at least one guide shaft 20 vertically fixed to the bottom of the test platform 1. The counterweight frame 21 is provided with a guide hole that mates with the guide shaft 20, and the guide shaft 20 passes through the guide hole, thereby providing precise vertical guidance for the lifting and lowering movement of the counterweight frame 21 and preventing it from swinging.

[0039] Its working principle is as follows: When the detection nut 28 is driven to move to the right by the lead screw 8, it pulls the pull rope 19 through the first connecting seat 11, pressure sensor 14, and second connecting seat 15. After passing over the fixed pulley 16, the pull rope 19 pulls the counterweight frame 21 upward. At this time, the weight of the counterweight block 22 and the counterweight frame 21 is converted into a constant horizontal leftward pulling force through the pull rope 19 and the pulley system, which acts on the second connecting seat 15, and is then transmitted to the detection nut 28 through the pressure sensor 14 and the first connecting seat 11, simulating its working load. This process is entirely driven by gravity, without any active vibration source.

[0040] Detection Unit: The detection unit is used to collect NVH data, and its core component is the vibration sensor 26. This vibration sensor 26 is directly mounted on the detection plane 13 of the nut positioning component 12, with its probe passing through the detection plane 13 and directly and tightly contacting the outer wall of the detection nut 28 inside the positioning hole. This contact mounting method can most directly and sensitively capture the micro-vibrations generated when the detection nut 28 moves along the lead screw 8 under load. The detection unit may also include a pressure sensor 14, with its two ends connected to the first connecting seat 11 and the second connecting seat 15, respectively. The pressure sensor 14 is used to detect and display the magnitude of the axial force applied to the detection nut 28 by the current load simulation unit in real time, facilitating monitoring and calibration of the load value.

[0041] Buffer device: A buffer 25 is provided at one end of the linear guide 9 near the bearing seat 6 (i.e., the starting end of the stroke of the detection nut 28). When the detection is completed or when a reset is required, the drive motor 3 reverses, the detection nut 28 moves to the left, and the first slider 10 slides to the left. The function of the buffer 25 is to collide with the first slider 10 when it slides to its limit position at this end, thus providing buffering and flexible limiting to protect the equipment.

[0042] This embodiment is not limited to this. Another implementation of the traction mechanism can be: a vertical rack is set below the testing platform, and a pinion meshing with the rack is installed on the counterweight frame. The pinion's shaft is converted into a horizontal traction force through a set of bevel gears or another set of pulleys and rope mechanisms, and then connected to the second connecting seat. The final effect is also to convert gravity into a horizontal pulling force, only the transmission path is different.

[0043] Brief description of the testing process: Insert the test nut 28 into the positioning hole of the nut positioning member 12, ensuring good contact between the vibration sensor 26 and it. According to the test requirements, place a counterweight block 22 of appropriate weight on the counterweight frame 21. Start the motor 3, which drives the lead screw 8 to rotate at a constant speed via the coupling 5. The rotation of the lead screw 8 drives the test nut 28, whose rotation is restricted, to move linearly to the right. The test nut 28 drives the first connecting seat 11 and the first slider 10 to move to the right, and through the pressure sensor 14, drives the second connecting seat 15 and the second slider 27 to move to the right. The second connecting seat 15 lifts the counterweight frame 21 via the pull rope 19 and the fixed pulley 16. The gravity of the counterweight block 22 is converted into a constant load force acting on the test nut 28 to the left. During this process, the vibration sensor 26 collects the vibration signal of the test nut 28 in real time to analyze the NVH performance of the lead screw and nut pair; the pressure sensor 14 displays the load force value in real time.

[0044] This invention achieves high-precision NVH performance testing of the lead screw and nut pair without interference at a low cost through innovative mechanical counterweight loading and vibration isolation design, which has significant practical and economic value.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An NVH detection device, characterized by, The utility model relates to a load simulation device for testing the vibration of a nut, comprising: a detection platform (1); a driving unit mounted on the detection platform (1) for providing rotary power; a screw rod (8) transmission unit comprising a screw rod (8) and a detection nut (28) rotatably coupled to the screw rod (8), the screw rod (8) being in transmission connection with the output end of the driving unit; a load simulation unit for providing a simulated load to the detection nut (28), comprising a counterweight assembly (18) and a traction mechanism for converting the gravity of the counterweight assembly (18) into an axial tension force on the detection nut (28); and a detection unit comprising a vibration sensor (26) for directly contacting and detecting the vibration of the detection nut (28).

2. The NVH detection apparatus according to claim 1, characterized by The load simulation unit comprises: a pulley block arranged on the detection platform (1); a counterweight assembly (18) arranged below the detection platform (1), the counterweight assembly (18) comprising a counterweight frame (21) capable of adding or removing counterweight blocks (22); and a pull rope (19) having one end connected to a force receiving component that moves synchronously with the detection nut (28) and the other end connected to the counterweight frame (21) after passing through the pulley block; wherein, when the detection nut (28) moves under the drive of the screw rod (8), the counterweight assembly (18) can be lifted or lowered through the transmission of the pull rope (19) and the pulley block, so that the gravity of the counterweight assembly (18) acts as a simulated load on the detection nut (28).

3. The NVH detection apparatus according to claim 2, characterized by The load simulation unit further comprises at least one vertically arranged guide shaft (20), the upper end of the guide shaft (20) being fixed to the bottom of the detection platform (1), and the counterweight frame (21) being provided with a guide portion that is in sliding cooperation with the guide shaft (20) for guiding the lifting movement of the counterweight assembly (18).

4. The NVH detection apparatus according to claim 1, characterized by, It further comprises a nut positioning assembly for limiting the rotation of the detection nut (28), the nut positioning assembly comprising: a nut positioning member (12) having a positioning hole opened on the side facing the screw rod (8), the inner edge of the positioning hole being provided with at least one positioning flat surface, and the detection nut (28) being installed in the positioning hole and being limited in rotation by the positioning flat surface; wherein, the nut positioning member (12) is further provided with a detection flat surface (13) in communication with the positioning hole, and the vibration sensor (26) is arranged on the detection flat surface (13) and directly contacts the outer wall of the detection nut (28) located in the positioning hole.

5. The NVH detection apparatus according to claim 4, characterized by It further comprises: a linear guide rail (9) fixedly installed on the detection platform (1) and arranged in parallel with the screw rod (8); a first sliding block (10) and a second sliding block (27) both being slidably arranged on the linear guide rail (9); a first connecting seat (11) installed on the first sliding block (10), and the nut positioning member (12) being fixed to the first connecting seat (11); a second connecting seat (15) installed on the second sliding block (27); wherein, the load simulation unit is connected to the second connecting seat (15).

6. The NVH detection apparatus according to claim 5, characterized by A pressure sensor (14) is further connected between the first connecting seat (11) and the second connecting seat (15) to detect the load force of the detection nut (28).

7. The NVH detection apparatus according to claim 5, characterized by A buffer (25) is further arranged on the linear guide rail (9) near the input end of the lead screw (8) to buffer and limit the first sliding block (10) sliding in this direction.

8. The NVH detection apparatus of claim 1, wherein, The driving unit comprises: a motor (3); a motor base (4) mounted on the detection table (1), the motor (3) being mounted on the detection table (1) through the motor base (4); and a shaft coupling (5) connected between the output shaft of the motor (3) and the lead screw (8).

9. The NVH detection apparatus of claim 1, wherein, The lead screw (8) transmission unit further comprises a bearing seat (6) fixed on the detection table (1) and a bearing (7) mounted in the bearing seat (6), the lead screw (8) being connected to the bearing seat (6) through the bearing (7), the driving unit being located on one side of the bearing seat (6), and the tension direction of the load simulation unit acting on the detection nut (28) being opposite to the bearing seat (6).

10. The NVH detection apparatus of claim 2, wherein, A via hole (24) is formed on the detection table (1) for the pull rope (19) of the load simulation unit to pass through.

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