Acceleration sensor flexible fixing tool and installation test structure

Abstract

This utility model belongs to the field of motor noise detection technology. To solve the problem of poor stability and relative displacement caused by rigid connection and press-fit testing of accelerometers, this utility model provides a flexible fixing fixture and installation test structure for accelerometers, including a connecting column. The tail end of the connecting column is used to fix a pushing mechanism, and the head end of the connecting column is fixedly connected to one end of a flexible block. An embedded part is embedded in the other end of the flexible block. The front end of the embedded part extends from the flexible block and is used to fix the accelerometer. The flexible block is injection molded from an elastic material. Compared with the prior art, this utility model uses a flexible block made of elastic material as a transition structure in the press-fit structure. By utilizing the compressibility of the flexible block, the pre-tightening force applied during the press-fit process helps to improve the press-fit stability.

Description

Technical Field

[0001] This utility model belongs to the field of motor abnormal noise detection technology, specifically relating to a flexible fixing fixture for an acceleration sensor and an installation and testing structure. Background Technology

[0002] The current principle for detecting abnormal noises in small motors and their assemblies (especially seat frame systems) is to use an acceleration sensor to identify abnormal vibrations or sounds caused by inherent quality defects or friction and interference during the operation of the adjustment motor or the adjustment process of the transmission mechanism in the electric seat frame.

[0003] In most current systems, accelerometers are directly pressed onto the surface of the workpiece by an automated mechanism (electric actuator, cylinder) to collect acceleration signals from the workpiece surface. These signals are then transmitted to a host computer, which processes the signals, separates characteristic indicators, and sets thresholds for distinguishing normal and abnormal workpieces, thereby identifying abnormal workpieces. However, the aforementioned accelerometer arrangement has poor stability, and the accelerometer is prone to relative displacement with the workpiece, affecting the signal acquisition effect. Furthermore, the accelerometer is rigidly connected to the pressing mechanism, making it susceptible to damage during repeated pressing processes. Utility Model Content

[0004] To address the issues of poor stability and relative displacement caused by rigid connection and press-fit testing of accelerometers, this invention provides a flexible fixing fixture and installation and testing structure for accelerometers.

[0005] The purpose of this utility model is achieved in the following manner: a flexible fixing fixture for an accelerometer includes a connecting column 1, the tail end of which is used to fix a pushing mechanism, the head end of which is fixedly connected to one end of a flexible block 2, and a pre-embedded part 3 is embedded and fixed in the other end of the flexible block 2. The front end of the pre-embedded part 3 extends out from the flexible block 2 and is used to fix an accelerometer 4. The flexible block 2 is injection molded from an elastic material.

[0006] The first anchor 11 extends forward from the head end of the connecting column 1. The first anchor 11 includes a connecting rod fixed to the head end of the connecting column 1. A disc-shaped structure is fixed at the front end of the connecting rod. The first anchor 11 is covered by the tail end of the flexible block 2. The embedded part 3 includes a columnar body embedded in the head end of the flexible block 2. A disc-shaped second anchor 31 extends outward from the tail end of the columnar body.

[0007] The front end of the columnar body of the embedded part 3 extends from the flexible block 2 and is provided with internal threads.

[0008] The flexible block 2 is spherical or cylindrical.

[0009] Furthermore, the connecting column 1 has a hollowed-out section in the middle.

[0010] Furthermore, the flexible block 2 is injection molded from silicone, and the silicone has a Shore hardness of 20~45.

[0011] Furthermore, for pressing forces of 30~50N, the silicone hardness is 25 Shore hardness, and for pressing forces of 90~110N, the silicone hardness is 40 Shore hardness.

[0012] An accelerometer installation and testing structure including the above-mentioned flexible fixed fixture includes a push rod 5. The output end of the push rod 5 is fixedly connected to one end of a pressure sensor 6, the other end of the pressure sensor 6 is fixedly connected to one end of a fixture mounting plate 7, the other end of the fixture mounting plate 7 is fixedly connected to the tail end of a connecting column 1, and the head end of a pre-embedded part 3 is fixedly connected to an accelerometer 4.

[0013] Furthermore, the tooling mounting plate 7, pressure sensor 6, and push rod 5 are connected in series and fixed by bolts; the tooling mounting plate 7 is provided with a limiting groove 71 on the side facing the pressure sensor 6, the small end of the screw passes through the limiting groove 71 and extends from the front end of the tooling mounting plate 7, and is used to fix the tail end of the connecting column 1. The large end of the screw is limited by the limiting groove 71 between the tooling mounting plate 7 and the pressure sensor 6, thus forming a fixed position.

[0014] Compared with the prior art, this utility model uses a flexible block made of elastic material as a transition structure in the press-fitting structure. By utilizing the compressibility of the flexible block, the pre-tightening force applied during the press-fitting process can help improve the press-fitting stability. Attached Figure Description

[0015] Figure 1 This is a structural diagram of one of the flexible fixed tooling solutions; Figure 2 This is a cross-sectional view of one of the flexible fixed tooling solutions; Figure 3 This is a structural diagram of the second flexible fixed tooling solution; Figure 4 This is a sectional view of the second flexible fixing fixture solution; Figure 5 This is a structural diagram of the third flexible fixed tooling solution; Figure 6 This is a schematic diagram of the accelerometer sensor installation and testing structure; Figure 7 This is a cross-sectional view of the front end of the accelerometer sensor mounting and testing structure; Figure 8 It is a diagram showing the natural frequency relationship of the vibration system.

[0016] Among them, the connecting column 1, the first anchor 11, the flexible block 2, the embedded part 3, the second anchor 31, the acceleration sensor 4, the push rod 5, the pressure sensor 6, the tooling mounting plate 7, and the limit groove 71. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] In this utility model, unless otherwise explicitly specified and limited, the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this utility model and 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 this utility model.

[0019] As attached Figure 1-7 As shown, a flexible fixture for fixing an accelerometer includes a connecting column 1, preferably made of aluminum alloy. The tail end of the connecting column 1 is used to fix a pushing mechanism, which can be a cylinder or an electric push rod. The head end of the connecting column 1 is fixedly connected to one end of a flexible block 2. An embedded part 3 is embedded in the other end of the flexible block 2. The front end of the embedded part 3 extends out of the flexible block 2 and is used to fix the accelerometer 4. The flexible block 2 is formed by injection molding of an elastic material through a mold. During injection molding, it forms a covering and adhesion with the connecting column 1 and the embedded part 3. The elastic material can be rubber, silicone, or other polymer materials.

[0020] Accelerometer 4 can be an axial acceleration sensor or a triaxial acceleration sensor; the length of the connecting column 1 can be adjusted according to the actual usage on site.

[0021] Further details are attached. Figure 2 , 4As shown, the first anchor 11 extends forward from the head end of the connecting column 1. The first anchor 11 includes a connecting rod fixed to the head end of the connecting column 1. A disc-shaped structure is fixed to the front end of the connecting rod. The first anchor 11 is covered by the tail end of the flexible block 2. The embedded part 3 includes a columnar body embedded in the head end of the flexible block 2. A disc-shaped second anchor 31 extends outward from the tail end of the columnar body. The first anchor 11 and the second anchor 31 are embedded in the flexible block 2 to a depth of at least 1 / 4 of the length of the flexible block 2 to ensure that the anchors will not come out.

[0022] Furthermore, the front end of the columnar body of the embedded part 3 extends from the flexible block 2 and is provided with an internal thread. The internal thread is used to connect one end of the screw, and the other end of the screw extends to connect the acceleration sensor 4. The internal thread provided on the base of the acceleration sensor 4 for mating is existing technology and does not require special adjustment.

[0023] Furthermore, the flexible block 2 is an attachment Figure 1 , 2 The spherical shape shown in Figure 5 or as attached Figure 3 , 4 The cylindrical shape shown.

[0024] Further details are attached. Figure 3 , 4 As shown, while ensuring sufficient support strength, a hollowed-out section is provided in the middle of the connecting column 1 to reduce weight.

[0025] Furthermore, in traditional industrial thinking, springs are often chosen as buffers for such vibration scenarios. However, the reason for insisting on using injection-molded elastic materials in this invention is that if a spring structure is used, the accelerometer 4 pressed against the surface of the workpiece can collect vibrations perpendicular to the surface of the workpiece (normal vibration). However, the workpiece often vibrates in multiple directions simultaneously. Since the accelerometer 4 placement mechanism is fixed to the testing stage, vibrations parallel to the contact plane (tangential vibration) will cause friction between the workpiece and the accelerometer 4, resulting in relative displacement. High-frequency friction will reduce the reliability of the accelerometer 4 and pose a risk of damage. At the same time, if a three-dimensional accelerometer is used, the acquisition of vibration signals parallel to the surface of the workpiece will be distorted.

[0026] The use of silicone blocks not only acts as a buffer during the placement of the accelerometer 4, similar to a spring structure, but also effectively adheres to the surface of the measured object during signal acquisition, reducing friction between the accelerometer 4 and the measured object in the tangential direction.

[0027] Furthermore, the hardness of the silicone directly affects the stiffness of the entire flexible sensor fixing system. The entire system is equivalent to a single-degree-of-freedom vibration system, see... Figure 8To avoid interference from the fixed system on signal acquisition (the target analysis frequency of vibration signals in the detection station system is usually higher than 20Hz), the system's natural frequency typically needs to be lower than 20Hz / 1.414 = 14.3Hz. Because silicone material possesses nonlinear stiffness characteristics, its stiffness will change under different pressure loads.

[0028] In typical testing environments for small motors and their assemblies, the pressing force is generally 30~50N. Our company has measured the current structure (silicone material) to have a Shore hardness of 20~30 (sh) through vibration testing. The system's natural frequency is below 14Hz. In particular, for the common 50N pressing force, a Shore hardness of 25 (silicone material) is the best choice. In testing environments for medium and large motors and their assemblies, under pressing force conditions of 90~110N, a Shore hardness of 35~45 is selected. In particular, for the common 100N pressing force, a Shore hardness of 40 (silicone material) is the best choice.

[0029] An accelerometer mounting and testing structure including the aforementioned flexible fixing fixture, as shown in the attached figure. Figure 6 , 7 As shown, it includes a push rod 5, which is a pneumatic or electric push rod. The output end of the push rod 5 is fixedly connected to one end of a pressure sensor 6. The pressure sensor 6 is a disc-shaped structure. The other end of the pressure sensor 6 is fixedly connected to one end of a tooling mounting plate 7. The other end of the tooling mounting plate 7 is fixedly connected to the tail end of a connecting column 1. The head end of the embedded part 3 is fixedly connected to an acceleration sensor 4.

[0030] Further details are attached. Figure 7 As shown, the tooling mounting plate 7, pressure sensor 6, and push rod 5 are connected in series and fixed by bolts. The tooling mounting plate 7 is provided with a limiting groove 71 on the side facing the pressure sensor 6, which matches the large end of the screw. The small end of the screw passes through the limiting groove 71 and extends from the front end of the tooling mounting plate 7 to fix the tail end of the connecting column 1. The tail end of the connecting column 1 is provided with a matching internal thread. The large end of the screw is limited by the limiting groove 71 between the tooling mounting plate 7 and the pressure sensor 6, thus forming a fixed position.

[0031] The working process of this utility model is as follows: The push rod 5 places the acceleration sensor 4 onto the target position of the workpiece under test, while simultaneously applying a certain preload. A pressure sensor 6 is installed at the end of the push rod 5 to read the pressure value in real time. The pressure value can be positively correlated with the compression of the silicone element. The pressure value can be adjusted by adjusting the stroke of the push rod 5. The pressure value is monitored by a PLC or host computer, and once it reaches the preset range of the flexible mounting mechanism, the system can start collecting signals.

[0032] This flexible mounting mechanism is suitable for automated inspection of products with non-magnetic bonding materials on their surfaces, such as household appliances and automotive parts with housings made of plastic and aluminum alloy. Different sensor specifications can be selected for different application scenarios.

[0033] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

Claims

1. A flexible fixing fixture for an accelerometer, characterized in that: It includes a connecting column (1), the tail end of which is used to fix the pushing mechanism, the head end of which is fixedly connected to one end of the flexible block (2), and a pre-embedded part (3) is embedded and fixed in the other end of the flexible block (2). The front end of the pre-embedded part (3) extends out from the flexible block (2) and is used to fix the acceleration sensor (4). The flexible block (2) is injection molded from an elastic material.

2. The flexible fixing fixture for an accelerometer as described in claim 1, characterized in that: The first anchor (11) extends forward from the head end of the connecting column (1). The first anchor (11) includes a connecting rod fixed to the head end of the connecting column (1). A disc-shaped structure is fixed at the front end of the connecting rod. The first anchor (11) is covered by the tail end of the flexible block (2). The embedded part (3) includes a columnar body embedded at the head end of the flexible block (2). The tail end of the columnar body extends outward to the circumferential side with a disc-shaped second anchor (31).

3. The flexible fixing fixture for an accelerometer as described in claim 2, characterized in that: The front end of the columnar body of the embedded part (3) extends from the flexible block (2) and is provided with internal threads.

4. The flexible fixing fixture for an accelerometer as described in claim 1, characterized in that: The flexible block (2) is spherical or cylindrical.

5. The flexible fixing fixture for an accelerometer as described in claim 1, characterized in that: The connecting column (1) has a hollowed-out section in the middle.

6. The flexible fixing fixture for an accelerometer as described in claim 1, characterized in that: The flexible block (2) is injection molded from silicone, which has a Shore hardness of 20 to 45.

7. The flexible fixing fixture for an accelerometer as described in claim 6, characterized in that: For pressing forces of 30~50N, the silicone hardness is 25 Shore A, and for pressing forces of 90~110N, the silicone hardness is 40 Shore A.

8. An accelerometer mounting and testing structure comprising the flexible fixing fixture as described in any one of claims 1-7, characterized in that: Includes a push rod (5), the output end of which is fixedly connected to one end of a pressure sensor (6), the other end of which is fixedly connected to one end of a tooling mounting plate (7), the other end of which is fixedly connected to the tail end of a connecting column (1), and the head end of an embedded part (3) is fixedly connected to an acceleration sensor (4).

9. The accelerometer sensor mounting and testing structure as described in claim 8, characterized in that: The tooling mounting plate (7), pressure sensor (6), and push rod (5) are connected in series and fixed by bolts. The tooling mounting plate (7) is provided with a limiting groove (71) on the side facing the pressure sensor (6). The small end of the screw passes through the limiting groove (71) and extends from the front end of the tooling mounting plate (7) to fix the tail end of the connecting column (1). The large end of the screw is limited by the limiting groove (71) between the tooling mounting plate (7) and the pressure sensor (6) to form a fixed position.

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