Blade clamp for high frequency high acceleration test

Abstract

The utility model discloses a vane clamp for high frequency high acceleration test, including a certain location clamping block, be equipped with the limiting slot for clamping vane on the location clamping block, the limiting slot is wide in, the location clamping block still is equipped with a square positioning hole, the both sides of square positioning hole form rigid support beam, the bottom of square positioning hole is equipped with center positioning hole, the location clamping block still is equipped with the counterweight of adjustable mass. This vane clamp sets up square positioning hole on the location clamping block, and the both sides of square positioning hole form rigid support beam, and the location clamping block forms a door beam structure, like this can effectively increase its inherent frequency, and simple structure, convenient design, through the additional counterweight of adjustable mass on the location clamping block, can accurately adjust the first order axial inherent frequency of clamp through the mass of counterweight adjustment, and can better satisfy the blade reliability test requirement.

Description

Technical Field

[0001] This utility model relates to the field of mechanical environment testing, and in particular to a fixture for high-frequency, high-acceleration reliability testing of turbine blades of air engines. Background Technology

[0002] With the rapid development of my country's aero-engine technology, higher requirements have been placed on the reliability testing of turbine blades, among which the assessment of fatigue life of turbine / compressor engine blades is particularly urgent. Turbine blades, due to their small size, high natural frequency (some test frequencies ≥15kHz), and the need to achieve excitation accelerations exceeding 1000g, are particularly vulnerable. Existing vibration test benches use a high-temperature epoxy adhesive bonding process for the moving coil, which significantly reduces the service life of the vibration bench when subjected to 1000g high-acceleration vibration.

[0003] Utility model patent (ZL 201320688723.6) discloses a high acceleration generating device for vibration testing equipment. It includes a clamp support body fixedly connected to the moving coil platform of the vibration testing equipment. At least two shafts are symmetrically arranged on the clamp support body, with the axis of each shaft perpendicular to the vibration direction of the vibration testing equipment. Each shaft has at least one sliding sleeve fitted onto it, and each sliding sleeve can move along the corresponding shaft and lock at any selected position. Each sliding sleeve is fixedly connected to a clamp used to fix the specimen. This device, by improving the specimen clamp structure, utilizes the resonance between the clamp and the moving coil to increase the acceleration value of the specimen by 10-30 times.

[0004] Although this fixture structure can amplify the acceleration value, it is complex and its resonant frequency needs to be changed by adjusting the position of the fixture vibration. The resonant frequency adjustment process is complicated during the test and has high requirements for the installation of the workpiece. It is not suitable for small engine blades. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a test fixture that can adjust the inherent frequency of the fixture and facilitate blade installation, in order to overcome the shortcomings of the prior art.

[0006] A blade clamp for high-frequency, high-acceleration testing includes a positioning clamping block. The positioning clamping block has a limiting groove for clamping the blade, which is wider inside and narrower outside. The positioning clamping block also has a square positioning hole, with rigid support beams formed on both sides of the square positioning hole. A central positioning hole is provided at the bottom of the square positioning hole. The positioning clamping block also has an adjustable counterweight.

[0007] Preferably, the positioning clamping block has a fixing bolt hole on the side opposite to the limiting slot, and the fixing bolt hole is connected to the limiting slot.

[0008] Preferably, the limiting slot is provided with a limiting top block.

[0009] Preferably, the counterweight and the positioning clamping block are fixedly connected by bolts.

[0010] Preferably, the counterweight is positioned on top of the positioning clamping block.

[0011] Preferably, the limiting slot is disposed above the square positioning hole.

[0012] The present invention has the following beneficial effects: the blade clamp is provided with a square positioning hole on the positioning clamping block, and rigid support beams are formed on both sides of the square positioning hole. The positioning clamping block forms a portal beam structure, which can effectively increase its natural frequency. Moreover, the structure is simple and easy to design. By adding an adjustable counterweight to the positioning clamping block, the first-order axial natural frequency of the clamp can be precisely adjusted by adjusting the mass of the counterweight, thereby better meeting the requirements of blade reliability testing.

[0013] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.

[0015] Figure 2 This is a schematic diagram of the installation structure of an embodiment of the present utility model.

[0016] Original part number description: 1. Positioning clamping block; 11. Limiting slot; 12. Limiting top block; 13. Fixing bolt hole; 14. Fixing bolt; 15. Square positioning hole; 16. Rigid support beam; 17. Center positioning hole; 2. Blade; 3. Counterweight block; 4. Bolt; 5. Vibration table surface; 6. Fixing bolt. Detailed Implementation

[0017] The following specific embodiments illustrate the implementation methods disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated beforehand. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention.

[0018] like Figure 1 As shown, this utility model discloses a blade clamp for high-frequency, high-acceleration testing, including a positioning clamping block 1. The positioning clamping block 1 has a limiting groove 11 for clamping a blade 2. The limiting groove 11 is wider on the inside and narrower on the outside. To facilitate the fixed connection between the blade 2 and the limiting groove 11, a fixing bolt hole 13 is provided on the side of the positioning clamping block 1 opposite to the limiting groove 11. The fixing bolt hole 13 communicates with the limiting groove 11. Thus, when fixing the blade, the blade 2 can be inserted into the limiting groove 11, and the fixing bolt 14 can be screwed into the limiting groove 11 through the fixing bolt hole 13 to tighten the blade, thereby fixing the blade 2. As a preferred embodiment, to achieve a better tightening effect, a limiting top block 12 can be provided in the limiting groove 11. The limiting top block 12 is located between the blade 2 and the fixing bolt 14, which further facilitates the fixing of the blade 2 on the clamp.

[0019] The positioning clamping block 1 is also provided with a square positioning hole 15, which is located in the lower half of the positioning clamping block 1. The limiting groove 11 is provided above the square positioning hole 15. On the positioning clamping block 1, rigid support beams 16 are formed on both sides of the square positioning hole 15. The two rigid support beams 16 are usually symmetrically arranged. In this way, by setting the square positioning hole 15, the positioning clamping block forms a portal beam structure. Compared with the commonly used cantilever beam structure, this can effectively increase its natural frequency. Moreover, the structure is simple, the design is convenient, and it is easier to install. A center positioning hole 16 is provided at the bottom of the square positioning hole 15.

[0020] The positioning clamping block 1 is also equipped with a counterweight block 3, which is fixedly connected to the positioning clamping block 1 by bolts 4. The counterweight block 3 is generally located on the top of the positioning clamping block. The mass of the counterweight block 3 is adjustable, and multiple counterweight blocks of different masses can be set, or the weight of the counterweight block can be reduced or increased during the debugging process.

[0021] like Figure 2 As shown, when in use, the blade clamp is fixed to the positioning clamping block 1 on the vibration table surface 5 using fixing bolts 6 through the central positioning hole 16. The mechanical model of the blade clamp can be equivalently represented as follows: the mass of the upper half of the square positioning hole 15 of the blade clamp, the mass of the blade 2, and the counterweight 3 together constitute a mass unit M1; the stiffness of the rigid support beams 16 on both sides of the square positioning hole 15 is equivalent to a spring unit K1; the mass of the lower half of the square positioning hole 15 and the mass of the moving coil of the vibration table together constitute a mass unit M2. According to the formula for calculating the first natural frequency of the clamp: f1 = / 2π means that during the fixture design process, a positioning and clamping block structure that meets the resonance condition can first be designed using 3D simulation software. Then, the natural frequency matching can be achieved by fine-tuning the mass of the counterweight. This allows the fixture's acceleration value to be amplified through resonance. For example, when the fixture has a 50x amplification effect, only a 20g acceleration output from the moving coil is needed to meet the 1000g test requirement. If the total mass of the moving parts of the system is 4kg, then only 800N of thrust is needed to generate an equivalent excitation effect of 40000N, thus significantly reducing the load requirements of the drive system.

[0022] The blade clamp has a square positioning hole on the positioning clamping block, and rigid support beams are formed on both sides of the square positioning hole. The positioning clamping block forms a portal beam structure, which can effectively increase its natural frequency. Moreover, the structure is simple and easy to design. By adding an adjustable counterweight to the positioning clamping block, the first-order axial natural frequency of the clamp can be precisely adjusted by adjusting the mass of the counterweight, thereby better meeting the requirements of blade reliability testing.

[0023] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention.

Claims

1. A blade clamp for high-frequency, high-acceleration testing, comprising a positioning clamping block, wherein the positioning clamping block is provided with a limiting groove for clamping the blade, the limiting groove being wider inside and narrower outside, characterized in that, The positioning clamping block is also provided with a square positioning hole, and rigid support beams are formed on both sides of the square positioning hole. A central positioning hole is provided at the bottom of the square positioning hole, and an adjustable counterweight is also provided on the positioning clamping block.

2. The blade clamp for high-frequency, high-acceleration testing according to claim 1, characterized in that: The positioning clamping block has a fixing bolt hole on the side opposite to the limiting slot, and the fixing bolt hole is connected to the limiting slot.

3. The blade clamp for high-frequency, high-acceleration testing according to claim 2, characterized in that: The limiting slot is equipped with a limiting top block.

4. The blade clamp for high-frequency, high-acceleration testing according to claim 1, characterized in that: The counterweight and the positioning clamping block are fixedly connected by bolts.

5. The blade clamp for high-frequency, high-acceleration testing according to claim 1, characterized in that: The counterweight is positioned on top of the positioning clamping block.

6. The blade clamp for high-frequency, high-acceleration testing according to claim 1, characterized in that: The limiting slot is located above the square positioning hole.

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