Device for testing bending fatigue life of elastic reed

Abstract

The utility model belongs to the technical field of microwave mechanical switches, and relates to a device for testing the bending fatigue life of an elastic reed. The device comprises a stepping motor, an outer shell and a rotating wheel, the stepping motor is fixed to the upper portion of the outer shell. A rotating shaft of the stepping motor is connected with the runner to drive the runner to rotate; the rotating wheel is located in the outer shell. The side surface of the outer shell is provided with a test window, and the test window is internally provided with a supporting structure for fixing a reed to be tested. And the rotating wheel is provided with a plurality of teeth which are uniformly distributed along the circumference. The number of cyclic loads can be calculated according to the number of electric pulses; when the main shaft of the stepping motor rotates for one circle, the applied cyclic load is increased by multiple times as rotating wheel teeth; the cyclic load is controllable; fatigue life measurement can be performed on batch reeds at the same time.

Description

Technical Field

[0001] This utility model belongs to the field of microwave mechanical switch technology and relates to a device for testing the bending fatigue life of an elastic spring. Background Technology

[0002] In the field of microwave mechanical switches, the reed, as a crucial component for electromagnetic field transmission and signal switching, is directly related to the electrical performance and reliability of the switch. The lifespan of the reed directly determines the lifespan of the microwave mechanical switch. During operation, the reed is subjected to repeated bending, which over time leads to the formation of micro-cracks that eventually fracture and fail – this is the fatigue life of the reed. Therefore, during the research and development phase, it is essential to have precise data on the fatigue life of the reed to ensure that the microwave mechanical switch operates within a reasonable timeframe.

[0003] The reeds in microwave mechanical switches exhibit small bending deformation, resulting in relatively low cyclic loads, but require very high fatigue life, typically N > 2 x 10⁻⁶. 7 The fatigue life is classified as ultra-high cycle fatigue. There are two main methods for determining fatigue life: analytical and experimental methods. Analytical methods calculate fatigue life using mathematical models based on the material's fatigue properties and the applied cyclic loads. Experimental methods obtain fatigue life data by simulating actual usage conditions and creating similar environments. Calculating the fatigue life of a spring using analytical methods is affected by various factors, such as the complexity of cyclic load deformation, differences in the material's crystal lattice after heat treatment, and irregular deformation due to surface coatings. These factors cannot be considered in analytical calculations, thus leading to inaccuracies. Experimental methods effectively avoid these drawbacks. Typical experimental methods use equipment such as insertion / removal machines to repeatedly apply insertion loads. However, for high-cycle fatigue life testing, the time required is very long, especially for 2x10 springs. 7 The test usually takes 2 to 3 weeks. If a reed is found to be broken, it takes even longer. In addition, the number of reeds tested at the same time is very small, and it causes great damage to the test equipment, resulting in high test costs. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention presents a device for measuring the fatigue life of elastic springs. A stepper motor drives and controls the rotation of a rotating wheel. The rotation of the wheel causes the teeth to actuate the spring. The periodic distribution of the wheel teeth simulates a cyclic load, and the deformation of the spring is controlled by adjusting the depth at which the spring penetrates the teeth, thus controlling the magnitude of the cyclic load. When the stepper motor spindle rotates one revolution, the cyclic load on the spring is equal to the number of teeth T on the wheel. Therefore, even when measuring over-cycle fatigue of a spring, the stepper motor only needs to rotate N / T revolutions, achieving a convenient, fast, and controllable measurement.

[0005] The technical solution provided by this utility model is: a device for testing the bending fatigue life of an elastic spring, comprising a stepper motor, a housing, and a rotating wheel; the stepper motor is fixed on the upper part of the housing; the rotating shaft of the stepper motor is connected to the rotating wheel and drives the rotating wheel to rotate; the rotating wheel is located inside the housing; a test window is provided on the side of the housing, and a support structure for fixing the spring to be tested is provided inside the test window; the rotating wheel is provided with a plurality of teeth evenly distributed along the circumference.

[0006] Preferably, the support structure includes a bracket and a spring mounting plate; the bracket is fixed to the outer shell, the spring mounting plate is fixed to the bracket, and the spring mounting plate has pre-drilled mounting holes; the spring mounting plate is fixed to the bracket through the mounting holes.

[0007] Preferably, the mounting hole is an oblong hole, used to adjust the insertion depth of the spring to be tested.

[0008] Preferably, the reeds to be tested are arranged in an array along the axis and circumference of the rotating wheel.

[0009] Preferably, the tips of the teeth are arc-shaped.

[0010] Preferably, an observation window is provided at the bottom of the outer casing.

[0011] Preferably, the device is suitable for measuring low cyclic loads and fatigue lives >10. 7 A resilient spring with multiple cycles.

[0012] Using the aforementioned device, an external electrical pulse signal drives a stepper motor shaft to rotate, which in turn drives a rotating wheel. Each tooth on the wheel actuates a spring, simulating the deformation of the spring under cyclic load. Each rotation of the stepper motor shaft results in the spring being subjected to several cyclic loads from the wheel teeth. The number of cyclic loads is calculated using the number of electrical pulses. Adjusting the insertion depth of the spring under test controls the amount of deformation, thereby controlling the magnitude of the cyclic load.

[0013] Compared with the prior art, the advantages of this utility model are: simple control, the number of cyclic loads can be calculated based on the number of electrical pulses; high efficiency, the applied cyclic load increases several times with the number of wheel teeth as the stepper motor spindle rotates once; the cyclic load is controllable; and fatigue life measurement of batch springs can be performed simultaneously. Attached Figure Description

[0014] Figure 1 An external view of the device used to test the bending fatigue life of an elastic spring;

[0015] Figure 2 Front view of an apparatus for testing the bending fatigue life of an elastic spring;

[0016] Figure 3Left, right, and rear views of the apparatus for testing the bending fatigue life of an elastic spring.

[0017] Figure 4 A top view of an apparatus for testing the bending fatigue life of an elastic spring;

[0018] Figure 5 A bottom view of an apparatus for testing the bending fatigue life of an elastic spring;

[0019] Figure 6 A longitudinal sectional view of an apparatus for testing the bending fatigue life of an elastic spring;

[0020] Figure 7 A transverse cross-sectional view of an apparatus for testing the bending fatigue life of an elastic spring;

[0021] Figure 8 This is a schematic diagram of the reed's shape;

[0022] Figure 9 This is a schematic diagram showing the deformation of the spring under test when it is inserted into the teeth at different depths; where (a) is inserted deeper and (b) is inserted shallower.

[0023] In the diagram, 1 is a stepper motor, 2 is the upper bearing, 3 is the motor mounting plate, 4 is the pin, 5 is the lower bearing, 6 is the outer casing, 7 is the rotating wheel, 8 is the spring being tested, 9 is the spring mounting plate, and 10 is the bracket. Detailed Implementation

[0024] To facilitate understanding of this utility model, it will be described in more detail below with reference to the accompanying drawings and specific embodiments. However, this utility model can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0025] The device for testing the bending fatigue life of an elastic spring provided by this utility model, such as... Figure 1-7 As shown, the device consists of a stepper motor 1, a motor mounting plate 3, a rotating wheel 7, a bearing, a housing 6, a pin 4, a spring mounting plate 9, and a bracket 10.

[0026] Stepper motor 1 is fixed to housing 6 via motor mounting plate 3. The shaft of stepper motor 1 drives wheel 7 to rotate via pin 4. Upper bearing 2 and lower bearing 5 ensure that wheel 7 rotates around the central axis and reduce friction during rotation. The spring 8 to be tested is fixed to spring mounting plate 9, which is fixed to bracket 10. Bracket 10 is fixed to housing 6 with screws. The teeth on wheel 7 are evenly distributed along the circumference, with rounded tips. The number of teeth T can be selected according to actual needs. The two ends of wheel 7 are positioned by upper bearing 2 and lower bearing 5 to ensure smooth rotation.

[0027] like Figure 1 and 6 As shown, the outer casing 6 has a perforated test window around its perimeter. A support structure consisting of a bracket 10 and a spring mounting plate 9 is arranged within the test window. The spring mounting plates 9 are arranged at a certain angle in the vertical direction from the outside in. Each spring mounting plate 9 has multiple rows of pre-drilled fixing holes from top to bottom. These fixing holes are used to mount the spring 8 to be tested. The spring mounting plates 9 are mounted on the bracket 10 by bolts and oblong holes. The length of the spring 8 inserted into the casing can be adjusted by moving the bolts within the oblong holes. The deeper the spring penetrates, the greater the deformation. Figure 8 and Figure 9 As shown in (a) and (b) in the figure. The springs to be tested can be arranged in an array along the axis and circumference of the rotating wheel 7 to realize the simultaneous fatigue life measurement of a batch of springs.

[0028] like Figure 5 As shown, an observation window is provided at the bottom of the outer casing 6, through which the position of the spring insert can be seen.

[0029] Stepper motor 1 receives digital control signals (electric pulse signals) from the outside and converts them into corresponding angular displacements. It is strictly synchronized in time. Therefore, as long as the number of pulses is controlled, the required rotation angle can be obtained. Thus, the cycle of the cyclic load can be equivalent to the number of pulses.

[0030] When testing the bending fatigue life of an elastic spring using the device provided by this utility model, the spring 8 to be tested is first fixed on the spring mounting plate 9, and then the spring mounting plate 9 is fixed on the bracket 10. The bracket 10 and the outer shell 6 are fixed with screws.

[0031] During measurement, an external electrical pulse signal drives the stepper motor 1 shaft to rotate, which in turn drives the wheel 7 to rotate. Each tooth on the wheel 7 actuates the spring, simulating the deformation of the spring under cyclic load. When the stepper motor shaft rotates once, the spring is subjected to T cyclic loads.

[0032] The deformation of the reed is controlled by adjusting the depth to which it is inserted between the teeth, thereby controlling the magnitude of the cyclic load. The number of cyclic loads is calculated by the number of electrical pulses.

[0033] The device provided by this invention is suitable for measuring devices with low cyclic load and fatigue life >10. 7 A resilient spring with multiple cycles.

Claims

1. A device for testing the bending fatigue life of an elastic spring, characterized in that: It includes a stepper motor, a housing, and a rotating wheel; the stepper motor is fixed to the upper part of the housing; the rotating shaft of the stepper motor is connected to the rotating wheel and drives the rotating wheel to rotate; the rotating wheel is located inside the housing; a test window is provided on the side of the housing, and a support structure for fixing the spring to be tested is provided in the test window; the rotating wheel has a number of teeth evenly distributed along the circumference.

2. The apparatus for testing the bending fatigue life of an elastic spring according to claim 1, characterized in that: The support structure includes a bracket and a spring mounting plate; the bracket is fixed to the outer shell, and the spring mounting plate has pre-drilled mounting holes; the spring mounting plate is fixed to the bracket through the mounting holes.

3. The apparatus for testing the bending fatigue life of an elastic spring according to claim 2, characterized in that: The mounting hole is an oblong hole used to adjust the insertion depth of the spring to be tested.

4. The apparatus for testing the bending fatigue life of an elastic spring according to claim 1, characterized in that: The reeds to be tested are arranged in an array along the axis and circumference of the rotating wheel.

5. The apparatus for testing the bending fatigue life of an elastic spring according to claim 1, characterized in that: The tips of the teeth are rounded.

6. The apparatus for testing the bending fatigue life of an elastic spring according to claim 1, characterized in that: An observation window is provided at the bottom of the outer casing.

7. The apparatus for testing the bending fatigue life of an elastic spring according to any one of claims 1-6, characterized in that: The device is suitable for measuring low cyclic loads and fatigue lives >10. 7 A resilient spring with multiple cycles.

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