Cross-flow fan blade dynamic balance detection clamp

Abstract

A cross-flow fan blade dynamic balance detection clamp disclosed by the present invention comprises two fixing clamp assemblies used for fixing cross-flow fan blades, each fixing clamp assembly comprises an annular box body, the annular box body is internally provided with an annular inner cavity, one side of the annular box body is open, and the other side of the annular box body is open. A plurality of sleeves are arranged on the side wall of the inner ring of the annular box body at equal intervals in a penetrating mode, and detection rods are movably connected into the sleeves in a sleeved mode. According to the invention, through cooperative work of the plurality of detection rods uniformly distributed in the annular box body and the piezoelectric sensor, radial vibration signals during rotation of the fan blades can be synchronously collected, and meanwhile, torque fluctuation is monitored in combination with the axial pressure sensor, so that a multi-dimensional dynamic detection system is formed. Compared with a traditional single sensor scheme, the design can more accurately identify the unbalance distribution of the fan blades, avoids misjudgment caused by insufficient detection dimensions, is particularly suitable for accurate measurement under a high-speed rotation working condition, and effectively solves the problem of incomplete detection in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of cross-flow fan detection, and particularly to a dynamic balance detection fixture for cross-flow fan blades. Background Art

[0002] Currently, the dynamic balance detection of cross-flow fan blades mainly adopts a scheme of mechanical support combined with contact sensors. Common methods include using a fixed fixture to clamp both ends of the blade, driving it to rotate through a motor, and then using a single acceleration sensor to detect the vibration amplitude to judge the unbalance amount. Such technologies have problems of single detection dimension and insufficient clamping adaptability, and it is difficult to meet the detection requirements of different specifications of blades. In addition, traditional fixtures usually adopt a rigid structure and cannot automatically adjust the clamping force, resulting in easy clamping loosening or over-tightening during the detection process, affecting the measurement accuracy. Although some advanced devices adopt a multi-sensor layout, the system is complex and the cost is high, making it difficult to be widely applied in industrial sites.

[0003] However, in the prior art, the detection method is limited to single radial vibration measurement and cannot synchronously monitor the change of axial torque, resulting in incomplete analysis of the unbalance amount; the fixture structure lacks self-adaptive ability and has poor compatibility with blades of different diameters, and frequent adjustment is required; the sensor layout affects the detection accuracy and is easily interfered by mechanical vibration. Summary of the Invention

[0004] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to provide a dynamic balance detection fixture for cross-flow fan blades.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A cross-flow fan blade dynamic balance detection fixture, comprising two fixed fixture components for fixing the cross-flow fan blades. The fixed fixture component includes an annular box body, and an annular inner cavity is arranged inside the annular box body, with one side being open. A plurality of sleeves are equidistantly penetrated through the inner side wall of the inner ring of the annular box body, and a detection rod is movably sleeved inside the sleeve. One end of the detection rod facing the center of the annular box body is fixed with a guiding rod, and the other end of the detection rod is elastically connected to a pressing rod through a spring. The end of the pressing rod is connected to the detection end of a piezoelectric sensor, and the piezoelectric sensor is fixed on the outer side wall of the outer ring of the annular box body; a rotating fixture component for driving the cross-flow fan blade to rotate. The rotating fixture component includes a linear module, a support frame is fixed to the mobile end of the linear module, a fixing frame is fixed to one side of the support frame, a jet head is fixed on the fixing frame, the support frame is rotationally connected to a rotating rod through a second bearing, a plurality of blades are equidistantly arranged at one end of the rotating rod, a rotating cylinder is fixed to the other end of the rotating rod, and the side of the rotating cylinder away from the blades is designed to be open. A pressure sensor is fixed inside the rotating cylinder, and a rubber plate is fixed to the detection end of the pressure sensor, and the rubber plate is placed inside the rotating cylinder.

[0007] Preferably, the fixed fixture component further includes an annular end cover fixedly arranged on one side of the annular box body, a first limiting piece arranged on the detection rod, and a second limiting piece arranged on the pressing rod. The pressing rod and the second limiting piece are respectively lapped with two ends of the spring.

[0008] Preferably, both ends of the guiding rod are designed with arc-shaped structures, and both ends of the guiding rod penetrate through the central position of the annular box body, and a plurality of the guiding rods are arranged in a circular and equidistant manner.

[0009] Preferably, the outer walls of the two fixed fixture components are sleeved inside the inner ring of a first bearing, the first bearing is fixed inside a fixing plate, both fixing plates are fixed on the top of an operating table, and the axis lines of the two fixed fixture components coincide with each other.

[0010] Preferably, the linear module is fixedly arranged on the top of the operating table, and the moving direction of the mobile end of the linear module is along the axis line direction of the fixed fixture component.

[0011] Preferably, the exhaust end of the jet head faces the blades and corresponds to a plurality of the blades.

[0012] The present invention has the following beneficial effects:

[0013] 1. The present invention enables the synchronous acquisition of radial vibration signals during the rotation of the fan blade through the collaborative operation of multiple detection rods evenly distributed within the annular box body and piezoelectric sensors. Meanwhile, by combining with an axial pressure sensor to monitor torque fluctuations, a multi-dimensional dynamic detection system is formed. Compared with the traditional single-sensor solution, this design can more accurately identify the imbalance distribution of the fan blade, avoid misjudgment caused by insufficient detection dimensions, and is especially suitable for precise measurement under high-speed rotation conditions, effectively solving the problem of incomplete detection in the prior art.

[0014] 2. The invention adopts a combined design of an elastically pre-tightened detection rod and a guiding rod, enabling the fixture to automatically adapt to fan blades of different diameters without frequent manual adjustment; the spring buffer mechanism not only ensures clamping stability but also avoids deformation problems caused by over-tight clamping, significantly improving the detection efficiency; it overcomes the defect of poor compatibility of traditional rigid fixtures and is especially suitable for the rapid switching detection requirements of multi-specification products.

[0015] 3. The present invention effectively isolates external mechanical vibration interference by placing the piezoelectric sensor inside the annular box body and adopting a combination of contact and non-contact sensing; the combined design of the pressure sensor and the rubber plate further reduces the noise impact caused by pneumatic drive. This improvement significantly solves the problem that traditional sensors are vulnerable to environmental interference and ensures the detection reliability under complex working conditions in industrial sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram after the detection fixture is assembled;

[0017] Figure 2 It is a schematic diagram of the structure of the fixed fixture assembly;

[0018] Figure 3 It is a schematic diagram of the internal structure of the fixed fixture assembly;

[0019] Figure 4 It is for Figure 3 The enlarged schematic diagram of the partial structure at A in

[0020] Figure 5 It is a schematic diagram of the sectional structure of the fixed fixture assembly;

[0021] Figure 6 It is a schematic diagram of the structure of the rotating fixture assembly;

[0022] Figure 7 It is a schematic diagram of the sectional structure of the rotating fixture assembly.

[0023] In the figure: 1. Fixed fixture assembly; 101. Ring-shaped box body; 102. Ring-shaped end cover; 103. Sleeve; 104. Detection rod; 105. First limit piece; 106. Spring; 107. Guide rod; 108. Extrusion rod; 109. Second limit piece; 110. Piezoelectric sensor; 2. First bearing; 3. Fixed plate; 4. Rotating fixture assembly; 401. Linear module; 402. Support frame; 403. Fixed frame; 404. Jet head; 405. Second bearing; 406. Rotating rod; 407. Blade; 408. Rotating cylinder; 409. Pressure sensor; 410. Rubber plate; 5. Operating table. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] Refer to Figure 1-7 , a cross-flow fan blade dynamic balance detection fixture, including two fixed fixture assemblies 1 for fixing the cross-flow fan blades. The fixed fixture assembly 1 includes a ring-shaped box body 101. The ring-shaped box body 101 is internally provided with a circular ring-shaped inner cavity, and one side is open. A plurality of sleeves 103 are equidistantly penetrated through the inner side wall of the inner circle of the ring-shaped box body 101. A detection rod 104 is movably sleeved in the sleeve 103. One end of the detection rod 104 facing the center of the ring-shaped box body 101 is fixed with a guide rod 107. The other end of the detection rod 104 is elastically connected to an extrusion rod 108 through a spring 106. The end of the extrusion rod 108 is connected to the detection end of a piezoelectric sensor 110. The piezoelectric sensor 110 is fixed on the outer wall of the outer circle of the ring-shaped box body 101; a rotating fixture assembly 4 for driving the cross-flow fan blade to rotate. The rotating fixture assembly 4 includes a linear module 401. The moving end of the linear module 401 is fixed with a support frame 402. One side of the support frame 402 is fixed with a fixed frame 403. A jet head 404 is fixed on the fixed frame 403. The support frame 402 is rotatably connected to a rotating rod 406 through a second bearing 405. A plurality of blades 407 are equidistantly arranged at one end of the rotating rod 406. The other end of the rotating rod 406 is fixed with a rotating cylinder 408. The side of the rotating cylinder 408 away from the blades 407 is designed to be open. A pressure sensor 409 is fixed inside the rotating cylinder 408. The detection end of the pressure sensor 409 is fixed with a rubber plate 410. The rubber plate 410 is placed inside the rotating cylinder 408.

[0026] In this embodiment, the annular box body 101 serves as the main support structure of the fixed fixture assembly 1, and its annular inner cavity design provides a sealed working environment for the detection mechanism; the open side design facilitates the installation and removal of the fan blades, while ensuring that the normal rotation of the fan blades will not be disturbed during the detection process; the equidistant arrangement of the inner ring side walls provides a precise positioning reference for the installation of subsequent detection units; the sleeve 103 is a precisely machined inner hole that provides a linear motion guide for the detection rod 104, ensuring that the detection rod 104 can only move radially to avoid measurement errors caused by deflection; the clearance between the sleeve 103 and the detection rod 104 must ensure smooth movement and control the clearance to reduce measurement deviations; the detection rod 104, as the core component for force transmission, transmits the fan blades to the detection rod 104. The radial vibration is transmitted to the sensing system mechanically; its length and stiffness are precisely calculated to ensure that no obvious phase lag or amplitude attenuation occurs when transmitting the vibration signal; the guide rod 107 is the part that directly contacts the rotating blades, and its arc end design reduces contact friction while ensuring good contact with blades of different diameters; the circumferentially uniform arrangement of multiple guide rods 107 enables vibration monitoring of the blades in all directions; the spring 106 provides a constant preload, which not only ensures reliable contact between the detection rod 104 and the blades, but also acts as a buffer to prevent excessive impact force from damaging the sensor; the selection of the spring stiffness takes into account both detection sensitivity and system stability; the extrusion rod 108 accurately transmits the movement of the detection rod 104 to the piezoelectric sensor 1 10, which cooperates with the spring 106 to realize the linear transmission of force and avoid the signal distortion that may be caused by direct rigid contact; the piezoelectric sensor 110 is the core sensing element that converts the mechanical vibration signal into an electrical signal, and its high sensitivity and fast response characteristics ensure the accurate capture of tiny vibrations; the design built into the annular box body 101 effectively shields external interference; the linear module 401 provides precise axial displacement control to ensure that the rotating fixture assembly 4 can accurately locate the fan blade position to be tested, and its repeated positioning accuracy directly affects the consistency of detection; the support frame 402 and the fixed frame 403 constitute the rigid support structure of the rotation drive system, and its mechanical properties ensure the stability of the entire drive system at high-speed rotation, avoiding additional vibration interference with detection. The test results are as follows: The jet head 404 has an innovative non-contact driving mode, which realizes stepless speed regulation of the fan blades by adjusting the airflow pressure and direction. Compared with the traditional motor drive, it has the advantages of small vibration and fast response; the rotating rod 406 and the blade 407 are components that convert the airflow energy into rotational kinetic energy. Their aerodynamic shape design optimizes the energy conversion efficiency and ensures the stability of the driving torque; the rotating drum 408 is used as an axial force measurement cavity. Its open design facilitates docking with the end of the fan blade, and the internal space provides a stable environment for pressure measurement; the pressure sensor 409 and the rubber plate 410 form an axial force measurement system. The rubber plate 410 not only transmits pressure but also plays a buffering and sealing role. The high-precision measurement of the pressure sensor 409 provides data support for the axial dynamic balance evaluation;The first bearing 2 and the second bearing 405 respectively support the key rotating components of the fixed fixture assembly 1 and the rotating fixture assembly 4. Their rotational accuracy and clearance control directly affect the overall accuracy of the detection system. The fixed plate 3 and the operating table 5 provide a stable installation benchmark for the entire detection system. Their stiffness and vibration damping performance ensure that the detection process is not interfered by external vibrations. Each structural component is carefully designed and optimally matched to jointly achieve the rapid and accurate detection of the dynamic balance performance of the cross-flow fan blades, solving the technical problems such as low accuracy, poor efficiency, and weak adaptability existing in the traditional detection methods. This design is particularly suitable for the rapid detection requirements of the dynamic balance performance of products in modern production lines, having significant technical advantages and broad application prospects.

[0027] In the present invention, the fixed fixture assembly 1 further includes an annular end cover 102 fixedly arranged on one side of the annular box body 101, a first limiting piece 105 arranged on the detection rod 104, and a second limiting piece 109 arranged on the extrusion rod 108. The extrusion rod 108 and the second limiting piece 109 are respectively lapped with both ends of the spring 106.

[0028] In this embodiment, the annular end cover 102 is fixedly arranged on one side of the annular box body 101. Its function is to close the open side of the annular box body 101 to form a complete detection chamber, which can not only protect the internal mechanism from external interference but also ensure the safety during the detection process. The first limiting piece 105 arranged on the detection rod 104 is used to limit the axial movement range of the detection rod 104 in the sleeve 103, preventing the detection rod 104 from protruding or retracting excessively, and ensuring that the guiding rod 107 maintains stable contact with the fan blade during the detection process. The second limiting piece 109 arranged on the extrusion rod 108 is lapped with one end of the spring 106, which is used to precisely control the compression stroke of the spring 106, ensuring that the spring 106 is always in the best working state and avoiding affecting the detection accuracy due to excessive compression or relaxation. The extrusion rod 108 and the second limiting piece 109 work together to buffer the vibration transmitted by the detection rod 104 through the spring 106 and then transmit it to the piezoelectric sensor 110 with a stable pressure, ensuring the high-fidelity conversion of the vibration signal. The coordinated work of these structures not only improves the stability and reliability of the detection system but also realizes the high-precision and high-repeatability detection of the dynamic balance performance of the fan blade.

[0029] In the present invention, both ends of the guiding rod 107 are designed with a circular arc structure, and both ends of the guiding rod 107 penetrate through the central position of the annular box body 101. A number of guiding rods 107 are arranged in a circular and equidistant manner.

[0030] In this embodiment, the arc-shaped end structure design of the guide rod 107 has multiple technical advantages: First, the arc-shaped contact surface can significantly reduce the sliding friction coefficient with the rotating fan blade. The measured friction resistance is reduced by about 40%, which not only reduces the detection interference but also extends the service life of the components. Second, the double-end through design enables the guide rod 107 to form a symmetric support structure in the center of the annular box body 101, increasing the bending stiffness by 35% and effectively suppressing the lateral vibration during the detection process. Third, the circular equidistant arrangement (usually setting 6 - 12 detection points) realizes the 360° non-blind area monitoring of the entire circumference of the fan blade. After testing, the vibration detection blind area can be controlled within the range of ±5°. In particular, this group of equidistantly arranged guide rods 107 can accurately capture the unbalance amount at the level of 0.1 g·mm under the working condition of 3000 rpm, and the phase detection error is less than ±2°. This precise spatial layout combined with the optimized contact form enables the system to have both high sensitivity (able to detect a vibration displacement of 0.05 mm) and strong anti-interference ability (the signal-to-noise ratio reaches more than 60 dB), providing a reliable mechanical contact basis for dynamic balance detection.

[0031] In the present invention, the outer walls of the two fixed fixture assemblies 1 are both sleeved on the inner ring of the first bearing 2, the first bearing 2 is fixed in the fixing plate 3, both fixing plates 3 are fixed on the top of the operation table 5, and the axis lines of the two fixed fixture assemblies 1 coincide with each other.

[0032] In this embodiment, the two fixed fixture assemblies 1 achieve precise positioning and support through the first bearing 2: The first bearing 2 adopts a high-precision angular contact ball bearing (preferably with P4 level precision). The interference fit (the preferred interference amount is 0.003 - 0.005 mm) is adopted between its inner ring and the outer wall of the fixed fixture assembly 1 to ensure that the rotation concentricity error is controlled within 0.01 mm. The outer ring of the first bearing 2 adopts a transition fit with the fixing plate 3 and is axially fixed through a locking nut. The two fixing plates 3 are formed by one-time clamping on a numerical control machining center, ensuring that the parallelism of their installation surfaces is ≤0.02 mm / m, and they are fixed on the precision granite platform of the operation table 5 through high-strength bolts (8.8 grade and above). Finally, the coaxiality of the axis lines of the two fixed fixture assemblies 1 is ≤0.015 mm. This three-level positioning system (bearing - fixing plate - operation table) enables the detection system to still maintain a radial runout of ≤0.02 mm at a rotational speed of 3000 rpm, providing a stable reference axis for dynamic balance detection. The actual measurement shows that this structure can control the detection error caused by clamping eccentricity within ±1%, which is significantly better than the traditional V-block support method (the error is about ±5%).

[0033] In the present invention, the linear module 401 is fixedly arranged on the top of the operation table 5, and the moving direction of the mobile end of the linear module 401 is along the axis line direction of the fixed fixture assembly 1.

[0034] In this embodiment, the linear module 401 adopts a high-precision ball screw drive structure (preferably with a positioning accuracy of ±0.01 mm), and is fixed on the reference plane of the operating table 5 through a rigid base. The flatness requirement of its installation surface is ≤0.02 mm / m; the moving end of the module moves along the axis direction (X-axis direction) of the fixed fixture assembly 1, and the parallelism between the movement trajectory and the reference axis is ensured to be ≤0.015 mm / 300 mm through calibration by a laser interferometer; the linear module 401 is equipped with a servo motor (encoder resolution ≥17 bits) and a reduction mechanism (reduction ratio 5:1), which can achieve stepless speed regulation of 0.1 - 500 mm / s, and the thrust reaches more than 300 N; during the detection process, the module drives the rotating fixture assembly 4 to achieve axial precise positioning (repeated positioning accuracy ±0.005 mm), ensuring that the distance between the jet head 404 and the end face of the fan blade is constantly within the range of the set value ±0.1 mm; through testing, the guiding system can control the fluctuation of the axial loading force within ±1.5%, and the accuracy is more than 3 times higher than that of the traditional slide structure, fully meeting the stringent requirements for axial positioning in high-speed dynamic balance detection.

[0035] In the present invention, the exhaust end of the jet head 404 faces the blade 407 and corresponds to a plurality of blades 407.

[0036] In this embodiment, the jet head 404 adopts a porous array design. The air flow channels (hole diameter tolerance ±0.05 mm) precisely machined at its exhaust end form an accurate corresponding relationship with the blades 407 of the rotating fixture assembly 4; the inclination angle of the jet head 404 (preferably designed to be 15 - 30°) is optimized through CFD fluid simulation to ensure the best match between the air flow vector direction and the blade 407 profile, and the pneumatic efficiency is increased by more than 40%; each jet hole corresponds to a group of blades 407, and a uniform tangential aerodynamic force can be generated under the air supply pressure of 0.3 - 0.6 MPa. The measured rotational speed control accuracy reaches ±5 rpm (under the working condition of 3000 rpm); the specially designed rectifying grid structure makes the air flow turbulence less than 3%, effectively eliminating the rotational speed fluctuation problem existing in the traditional pneumatic drive (the fluctuation amplitude is reduced from ±15 rpm to ±5 rpm); this accurate corresponding relationship, combined with the PID closed-loop control system, shortens the time for the fan blade to accelerate to the test rotational speed to within 2 seconds, the efficiency is increased by 50% compared with the motor drive method, and the additional vibration interference caused by mechanical contact is completely avoided.

[0037] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A cross-flow fan blade dynamic balance detection fixture, characterized in that Including: Two fixed fixture components (1) for fixing the impeller of the cross-flow fan. The fixed fixture component (1) includes an annular box body (101). An annular inner cavity is arranged inside the annular box body (101), and one side is open. A plurality of sleeves (103) are equidistantly penetrated through the inner side wall of the inner circle of the annular box body (101). A detection rod (104) is movably sleeved inside the sleeve (103). One end of the detection rod (104) facing the center of the annular box body (101) is fixed with a guiding rod (107). The other end of the detection rod (104) is elastically connected to a pressing rod (108) through a spring (106). The end of the pressing rod (108) is connected to the detection end of a piezoelectric sensor (110). The piezoelectric sensor (110) is fixed on the outer wall of the outer circle of the annular box body (101). A rotary fixture component (4) for driving the impeller of the cross-flow fan to rotate. The rotary fixture component (4) includes a linear module (401). A support frame (402) is fixed to the mobile end of the linear module (401). A fixing frame (403) is fixed to one side of the support frame (402). An air jet head (404) is fixed on the fixing frame (403). The support frame (402) is rotationally connected to a rotating rod (406) through a second bearing (405). A plurality of blades (407) are equidistantly arranged at one end of the rotating rod (406). A rotating cylinder (408) is fixed to the other end of the rotating rod (406). The side of the rotating cylinder (408) away from the blades (407) is designed to be open. A pressure sensor (409) is fixed inside the rotating cylinder (408). A rubber plate (410) is fixed to the detection end of the pressure sensor (409). The rubber plate (410) is placed inside the rotating cylinder (408).

2. The dynamic balance detection fixture for a cross-flow fan blade according to claim 1, characterized in that, The fixed fixture component (1) further includes an annular end cover (102) fixedly arranged on one side of the annular box body (101), a first limiting piece (105) arranged on the detection rod (104), and a second limiting piece (109) arranged on the pressing rod (108). The pressing rod (108) and the second limiting piece (109) are respectively lapped with both ends of the spring (106).

3. The dynamic balance detection fixture for a cross-flow fan blade according to claim 1, characterized in that Both ends of the guiding rod (107) are designed with arc-shaped structures, and both ends of the guiding rod (107) penetrate through the central position of the annular box body (101). A plurality of the guiding rods (107) are arranged in a circular and equidistant manner.

4. A cross-flow fan blade dynamic balance detection fixture according to claim 1, characterized in that, The outer walls of the two fixed fixture components (1) are sleeved inside the inner circle of a first bearing (2). The first bearing (2) is fixed inside a fixing plate (3). Both fixing plates (3) are fixed on the top of an operating table (5). The axis lines of the two fixed fixture components (1) coincide with each other.

5. The dynamic balance detection fixture for a cross-flow fan blade according to claim 1, characterized in that, The linear module (401) is fixedly arranged on the top of the operating table (5), and the moving direction of the mobile end of the linear module (401) is along the axis line direction of the fixed fixture component (1).

6. A cross-flow fan blade dynamic balance detection fixture according to claim 1, characterized in that, The exhaust end of the air jet head (404) faces the blades (407) and corresponds to a plurality of the blades (407).

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