Clamping force testing device

Abstract

The utility model belongs to the technical field of earphone testing, and discloses a clamping force testing device which comprises a product fixing assembly, an attaching assembly, a driving assembly and a position detection assembly. The product fixing assembly is provided with a width-adjustable clamping groove, the clamping groove is configured to position a fixed part of a to-be-detected product in the width direction of the clamping groove, and the width of the clamping groove is adjustable; the attaching assembly comprises two attaching pieces arranged on the two sides of the product fixing assembly, and the attaching pieces are configured to make contact with the stretching part of the to-be-tested product; the driving assembly is configured to drive at least one of the two attaching pieces to move so that the distance between the two attaching pieces can be adjusted. The position detection assembly is configured to detect the distance between the two attaching pieces. The clamping force testing device provided by the utility model has relatively high testing accuracy.

Description

Technical Field

[0001] The utility model relates to the technical field of earphone testing, in particular to a clamping force testing device. Background Art

[0002] Headphones are widely used because of their good sound quality. When a user wears headphones, the headband of the headphones provides a clamping force to fix the headphones on both sides of the user's head, and the ear pads of the headphones can play a buffering role. The size of the headphone clamping force and the tightness of the ear pads will affect the user's comfort and hearing experience. The size of the clamping force is usually designed according to the weight of the headphones. When the clamping force is too large, although there will be no sound leakage, the user will feel uncomfortable. If the clamping force is too small, sound leakage will occur.

[0003] In the prior art, it is necessary to test the clamping force of wearable headphones to balance the quality of the headphones in terms of clamping force, comfort and sound effects. The clamping force testing device in the prior art usually includes a fixing fixture, a connecting rod mechanism and a metal support. The fixing fixture is used to set the headband of the headphones. The ear pads of the headphones are close to the metal support. The clamping force of the headphones is evenly transmitted to the force sensor in the middle by the connecting rod mechanism, so that the force sensor measures the total clamping force. During the test, it is necessary to manually pull the headphones apart so that the two ear pads move back to back, and then set the headband of the headphones on the fixing fixture, shrink the headphones inward and make the two ear pads in close contact with the metal support, so that the clamping force applied by the headphones on the metal support is transmitted to the force sensor in the middle through the connecting rod mechanism.

[0004] However, manually expanding the headband outward and then hanging the earphones on the fixing fixture and the metal support can easily cause measurement errors due to differences in the external stretching speed, which in turn leads to low accuracy in testing the clamping force, which urgently needs to be improved. Utility Model Content

[0005] The utility model aims to provide a clamping force testing device with higher testing accuracy.

[0006] As conceived above, the technical solution adopted by the utility model is:

[0007] Clamping force test device, comprising:

[0008] A product fixing component, wherein the product fixing component is provided with a slot with adjustable width, the slot is configured to locate the fixing part of the product to be tested in its width direction, and the width of the slot is adjustable;

[0009] An abutment assembly, comprising two abutment members disposed on both sides of the product fixing assembly, the abutment members being configured to contact the stretched portion of the product to be tested;

[0010] a driving assembly configured to drive at least one of the two abutting members to move so that the distance between the two abutting members is adjustable; and

[0011] The position detection component is configured to detect the distance between the two abutment members.

[0012] Optionally, the product fixing assembly includes a fixing rod and two limiting members sleeved on the fixing rod, the position of each limiting member in the axial direction of the fixing rod is adjustable, and the two limiting members and the fixing rod cooperate to form a slot.

[0013] Optionally, the clamping force testing device further comprises a supporting assembly, and the product fixing assembly is arranged on the supporting assembly in an adjustable manner along the first direction.

[0014] Optionally, the support assembly includes a base and a support frame, the support frame is arranged on the base so that its position can be adjusted along the second direction, and the product fixing assembly is arranged on the support frame so that its position can be adjusted along the first direction.

[0015] Optionally, one of the two abutment members is connected to the drive assembly, and the other abutment member is arranged on the support frame.

[0016] Optionally, the clamping force testing device further comprises a supporting assembly, and the two abutting members are both arranged on the supporting assembly in an adjustable manner along the first direction;

[0017] The driving component drives one of the two abutting components to move closer to or away from the other, and the abutting component driven by the driving component to move slides along the second direction on the supporting component.

[0018] Optionally, the clamping force testing device further comprises a connecting block, which is slidably connected to the supporting assembly and connected to the output end of the driving assembly, and the abutment member driven to move by the driving assembly is adjustably arranged on the connecting block along the first direction.

[0019] Optionally, the connecting block includes a first part and a second part and a third part connected to the same side of the first part, the output end of the driving component is connected to the second part, the first part is connected to a slider, the supporting component is provided with a slide rail, the slider and the slide rail are slidably matched, the third part is provided with a first elongated hole extending along the first direction, the fixing part passes through the first elongated hole and is connected to the abutment part driven to move by the driving component.

[0020] Optionally, the clamping force testing device further comprises a supporting assembly, and the position detecting assembly is arranged on the supporting assembly so as to be adjustable in position along the second direction.

[0021] Optionally, the driving assembly includes a pressure regulating system, a cylinder and a pressure detecting component, the pressure regulating system is configured to input gas into the cylinder, the cylinder is configured to drive the two abutments away from each other, and the pressure detecting component is configured to measure the gas pressure output by the pressure regulating system.

[0022] The clamping force testing device provided by the utility model has at least the following beneficial effects:

[0023] The fixed part of the product to be tested is positioned by the product fixing component to prevent the product to be tested from being displaced in the width direction of the slot during the test, which would affect the test results. The two abutment members of the abutment component are respectively located on both sides of the product fixing component and are configured to contact the stretched part of the product to be tested. The two abutment members are driven away from each other by the driving component to achieve stretching of the stretched part, so that the product to be tested is pulled apart. Compared with the manual pulling method, the driving component can control the outward stretching speed of the product to be tested, has higher stability, and has good repeatability of multiple tests, thereby reducing measurement errors and improving the accuracy of clamping force testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The structure diagram of the clamping force testing device provided by the embodiment of the utility model is as follows Figure 1 ;

[0025] Figure 2 The structure diagram of the clamping force testing device provided by the embodiment of the utility model is as follows Figure 2 ;

[0026] Figure 3 The structure diagram of the clamping force testing device provided by the embodiment of the utility model is as follows Figure 3 ;

[0027] Figure 4 It is a structural schematic diagram of a connection block provided in an embodiment of the utility model;

[0028] Figure 5 The structure diagram of the clamping force testing device provided by the embodiment of the utility model is as follows Figure 4 ;

[0029] Figure 6 It is a relationship diagram between the stretching speed and the stretching force measurement results provided by the embodiment of the utility model.

[0030] In the figure:

[0031] 100, product fixing assembly; 101, slot; 110, fixing rod; 120, limiting member; 130, fixing block; 140, fixing plate; 141, third elongated hole; 200, abutting assembly; 210, abutting member; 211, fourth elongated hole; 300, driving assembly; 310, cylinder; 400, position detection assembly; 500, supporting assembly; 510, base; 511, second elongated hole; 512, fifth elongated hole; 520, supporting frame; 600, connecting block; 610, first part; 620, second part; 630, third part; 631, first elongated hole; 700, slider; 800, slide rail. DETAILED DESCRIPTION

[0032] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only configured to explain the present invention, rather than to limit the present invention. It should also be noted that, for the sake of ease of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0033] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present utility model, unless otherwise clearly stipulated and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. In the description of this embodiment, unless otherwise specified, "multiple" specifically refers to two or more.

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only configured to distinguish in the description and have no special meaning.

[0037] Before introducing the clamping force testing device provided by the present invention, "the measurement error caused by the difference in the external tensioning speed" is explained in detail.

[0038] Taking headphones as an example, the existing method for evaluating the comfort and fit of users when using headphones often uses clamping force as an evaluation parameter. After fixing the headphones on the fixture, the ear pads are close to the metal support, and the clamping force is evenly transmitted to the force sensor in the middle using the connecting rod mechanism to measure the total clamping force. However, due to the design of the connecting rod mechanism, it is easy to cause errors in the measurement results due to different placement of the headphones, so the production line tolerance has to be enlarged, resulting in low product quality. As shown in Table 1, multiple sets of clamping force measurement results show that the repeatability error of the results has reached ±10%.

[0039] Table 1

[0040]

[0041] It should be noted that the cause of poor repeatability also involves product material issues. The tensile properties of the material include linear rigidity and nonlinear viscoelasticity of the Young's modulus. Viscoelasticity is equivalent to system damping when stretched. The stretching speed will affect the clamping force measured at a fixed stretching distance. Existing measurement equipment requires someone to manually stretch the headband and then hang the earphones on a fixed fixture, so it is easy to produce measurement errors due to differences in the external stretching speed. For details, please refer to the Taiwan Standard 10020-Vulcanized Rubber or Thermoplastic Rubber Stress Relaxation Test Method for Tensile Strength Measurement. An experiment was designed based on this method to verify how the external stretching speed affects the clamping force measurement results. See. Figure 6 , two test pieces of the same specification showed different tensile force measurement results in the tests of two different tensile speeds. The faster tensile condition had a higher tensile force peak; the slower tensile condition had a lower tensile force peak, and the difference between the two exceeded 10%. Among them, Figure 6 The horizontal axis is time, the unit is seconds; the vertical axis is force, the unit is Newton.

[0042] In summary, there are two reasons why the existing equipment has poor repeatability: first, the design of the equipment's connecting rod mechanism is easily affected by differences in placement and the measurement results; second, it is difficult to control the speed at which the earphones are stretched manually, resulting in excessive differences in the clamping force displayed by the product itself.

[0043] Based on the above problems, this embodiment provides a clamping force testing device, which is configured to test the clamping force of a product to be tested and has high accuracy.

[0044] The clamping force testing device provided in this embodiment can be configured to test the clamping force of headphones, that is, the product to be tested can be a headphone, and the clamping force testing device provided in this embodiment does not need to be manually pulled open when using the headphone. It should be noted that the headphone includes a headband and ear pads connected to both ends of the headband. This embodiment is described by taking the headphone as the product to be tested as an example. Of course, it can be understood that the product to be tested can also be other products, and this embodiment does not limit this.

[0045] like Figures 1 to 5 As shown, the clamping force testing device includes a product fixing component 100 , a contact component 200 , a driving component 300 and a position detection component 400 .

[0046] The product fixing component 100 is provided with a slot 101 with adjustable width, and the slot 101 is configured to locate the fixing part of the headset in the width direction thereof, so as to realize the positioning of the headset in the width direction of the slot 101. In this embodiment, the fixing part may be the middle part of the headband. In this embodiment, the product fixing component 100 is provided with a slot 101, and the slot 101 is configured to accommodate the headband. The width of the slot 101 is adjustable, so as to realize the fixing of headbands of different widths, thereby improving the flexibility and versatility of the product fixing component 100.

[0047] The abutment component 200 includes two abutment members 210 disposed on both sides of the product fixing component 100, the two abutment members 210 are disposed opposite to each other in the second direction, and each abutment member 210 is configured to contact the stretched portion of the headset. It should be noted that the stretched portion of the headset may be an ear pad. In this embodiment, two ear pads are provided, and the two ear pads correspond to the two abutment members 210 one by one, and each abutment member 210 contacts the corresponding ear pad. In this embodiment, the ear pad contacts the side of the corresponding abutment member 210 facing away from the other abutment member 210.

[0048] The driving assembly 300 in this embodiment is configured to drive at least one of the two abutting members 210 to move, so that the distance between the two abutting members 210 can be adjusted, such as the two abutting members 210 are moved closer to each other or farther away from each other. When the distance between the two abutting members 210 gradually increases, the distance between the two ear pads will gradually increase, thereby achieving the pulling apart of the headphone.

[0049] The position detection assembly 400 is configured to detect the distance between the two abutting members 210. By determining whether the distance between the two abutting members 210 reaches a preset distance and the external force exerted on the two abutting members 210 when they are moving away from each other, it can be determined whether the clamping force of the headset meets the requirements.

[0050] By way of example, the position detection component 400 may include a photoelectric detection switch (or a photoelectric induction switch). When the distance between the two abutments 210 reaches a preset distance, the photoelectric detection switch generates a first signal. When the distance between the two abutments 210 is not the preset distance, the photoelectric detection switch generates a second signal. The first signal and the second signal are used to determine whether the clamping force of the headset is sufficient, too large, or too small. By way of example, the first signal may be a high potential, and the second signal may be a low potential. It should be noted that the position detection component 400 may also be other detection components in the prior art, as long as it can detect the distance between the two abutments 210, and this embodiment is not limited thereto.

[0051] When using the clamping force testing device provided in this embodiment, the headset is first hung on the product fixing component 100, and the card slot 101 limits the headband of the headset in its width direction. Then, the driving component 300 is controlled to drive the distance between the two abutting members 210 to be the first distance. It should be noted that the first distance is slightly less than or equal to the distance between the two ear pads of the headset when the headset is in an undeformed state. Afterwards, the two ear pads of the headset are respectively brought into contact with the sides of the two abutting members 210 that are away from each other. At this time, the headset is not opened under force. Next, the driving component 300 drives at least one of the two abutting members 210 to move, so that the distance between the two abutting members 210 gradually increases, and records the magnitude of the force applied by the driving component 300 to the abutting member 200. At the same time, the position detection component 400 detects the distance between the two abutting members 210. When the distance between the two abutting members 210 is the second distance, the driving component 300 can be controlled to stop driving. At this time, the force applied by the driving component 300 to the abutting member 200 is recorded, so as to achieve the purpose of judging whether the clamping force of the headphone is sufficient by position. The difference between the second distance and the first distance is the deformation size of the headphone. For example, assuming that the wearable headset expands outward by 150 mm, a clamping force of 3.0 N should be measured; when the thrust force applied by the driving component 300 to the abutment component 200 is 3.0 N, when the outward extension distance of the wearable headset is greater than 150 mm, it indicates that the headband of the wearable headset is too loose, resulting in insufficient clamping force; conversely, if the outward extension distance is much less than 150 mm, it indicates that the clamping force of the headband is too large.

[0052] The clamping force testing device provided in this embodiment positions the fixed part of the product to be tested through the product fixing component 100 to prevent the product to be tested from being displaced in the width direction of the card slot 101 during the test, which affects the test results. The two abutment members 210 of the abutment component 200 are respectively located on both sides of the product fixing component 100, and are configured to contact the stretched part of the product to be tested. The two abutment members 210 are driven away from each other by the driving component 300, thereby achieving stretching of the stretched part, so that the product to be tested is pulled apart. Compared with the manual pulling method, the driving component 300 can control the outward stretching speed of the product to be tested, has higher stability, and has good repeatability of multiple tests, thereby reducing measurement errors and improving the accuracy of the clamping force test.

[0053] Furthermore, in this embodiment, the abutment member 210 is driven directly by the driving assembly 300 without using a connecting rod mechanism, so that the test result will not be affected by the placement position of the product to be tested, and the test accuracy is high.

[0054] Alternatively, if Figure 1As shown, the product fixing assembly 100 includes a fixing rod 110 and two limiting members 120 sleeved on the fixing rod 110. The setting position of each limiting member 120 in the axial direction of the fixing rod 110 is adjustable, so that the distance between the two limiting members 120 is variable. The two limiting members 120 and the fixing rod 110 cooperate to form a card slot 101, so that the width of the card slot 101 is adjustable. The headband of the headset can be limited between the two limiting members 120, so as to limit the headband.

[0055] The structure of the product fixing assembly 100 provided in this embodiment is relatively simple, so that the cost of the clamping test device is relatively low. For example, the stopper 120 is specifically a cylinder. In this embodiment, the stopper 120 is annular, and the stopper 120 is provided with a through hole penetrating its inner wall and outer wall. The bolt passes through the screw hole and is pressed against the fixing rod 110, so that the stopper 120 is fixed on the fixing rod 110.

[0056] Further optionally, if Figure 1 As shown, the clamping force testing device further includes a support assembly 500, and the product fixing assembly 100 is adjustably arranged on the support assembly 500 along the first direction, so as to be applicable to headphones with different heights, so as to ensure that the ear pad can smoothly contact the abutment member 210. In this embodiment, the first direction is Figure 2 Up and down directions shown.

[0057] It should be noted that if Figure 1 As shown, the product fixing assembly 100, the abutting assembly 200, the driving assembly 300 and the position detecting assembly 400 are all arranged on the supporting assembly 500, and are connected into a whole through the supporting assembly 500, so as to facilitate the overall movement of the clamping force testing device.

[0058] In some optional embodiments, such as 2 or Figure 3 As shown, the support assembly 500 includes a base 510 and a support frame 520. The support frame 520 is adjustably disposed on the base 510 along the second direction, and the product fixing assembly 100 is adjustably disposed on the support frame 520 along the first direction. Since the support frame 520 is adjustably disposed on the base 510 along the second direction, and the product fixing assembly 100 is disposed on the support frame 520, the position of the product fixing assembly 100 in both the first direction and the second direction can be adjusted, thereby improving the flexibility of the product fixing assembly 100 and further improving the application range of the clamping force testing device.

[0059] Further optionally, a second elongated hole 511 extending along the second direction is provided on the base 510 , and a bolt passes through the second elongated hole 511 from the bottom surface of the base 510 and is connected to the threaded hole on the support frame 520 to achieve the connection between the support frame 520 and the base 510 .

[0060] For example, the support frame 520 is in the form of a gantry, both ends of which are connected to the base 510. The product fixing assembly 100 also includes two fixing blocks 130, and the fixing rod 110 is connected between the two fixing blocks 130. In some embodiments, the fixing rod 110 is rotatably connected to the fixing block 130 through a bearing. It should be noted that the fixing rod 110 is located above the support frame 520 in the first direction, so that the support frame 520 does not affect the movement of the fixing rod 110 in the first direction. A fixing plate 140 is connected to each fixing block 130, and the fixing plate 140 is provided with a third elongated hole 141 extending along the first direction. The bolt passes through the third elongated hole 141 and is connected to the threaded hole on the support frame 520, thereby realizing the connection between the fixing plate 140 and the support frame 520. It should be noted that each fixing block 130 can be connected to a fixing plate 140 on both sides in the second direction to improve the connection stability and reliability between the product fixing assembly 100 and the support frame 520, thereby reducing the probability of the headphone moving during the test.

[0061] Optionally, one of the two abutment members 210 is connected to the driving assembly 300, so that the driving assembly 300 drives the one abutment member 210 to move closer to or away from the other abutment member 210, thereby achieving the two abutment members 210 approaching or moving away from each other; the other abutment member 210 is arranged on the support frame 520, so that the other abutment member 210 can move in the second direction relative to the base 510, and has a larger range of applications.

[0062] In some optional embodiments, the two abutment members 210 are both adjustably disposed on the support assembly 500 along the first direction. On the one hand, the position of the abutment member 210 in the first direction can be adjusted to enable better contact with the ear pad. For example, the ear pad can contact the center of the abutment member 210 to make the force more uniform. On the other hand, the two abutment members 210 can be closer to the base 510 to facilitate the storage of the clamping force testing device and reduce the space it occupies.

[0063] For example, Figure 5 As shown, a support member 210 is adjustably arranged on a support frame 520 along a first direction, and the support member 210 is provided with a fourth elongated hole 211 extending along the first direction. A bolt passes through the fourth elongated hole 211 and is connected to a threaded hole on the support frame 520, thereby realizing the connection between the support member 210 and the support frame 520.

[0064] In this embodiment, one of the two abutment members 210 is connected to the driving component 300, that is, the driving component 300 drives one of the two abutment members 210 to move, and the abutment member 210 driven to move by the driving component 300 is slidably disposed along the second direction on the base 510 of the supporting component 500, so that the base 510 can guide the movement of the abutment member 210, so that the abutment member 210 can move along the second direction without deviation.

[0065] Alternatively, if Figure 2 As shown, the clamping force testing device further includes a connecting block 600. The connecting block 600 is slidably connected to the base 510 of the supporting assembly 500, the abutting member 210 driven by the driving assembly 300 is adjustably arranged on the connecting block 600 along the first direction, and the output end of the driving assembly 300 is drivingly connected to the connecting block 600. By setting the connecting block 600, the abutting member 210 can be slidably arranged on the base 510, can be connected to the driving assembly 300, and can be adjusted in position along the first direction.

[0066] For example, a bolt passes through the fourth elongated hole 211 on the abutment member 210 and is connected to the threaded hole on the connection block 600 , thereby achieving connection between the abutment member 210 and the connection block 600 .

[0067] In some optional embodiments, such as Figure 4 As shown, the connection block 600 includes a first portion 610 and a second portion 620 and a third portion 630 connected to the same side of the first portion 610, that is, the connection block 600 is U-shaped. The output end of the driving assembly 300 is connected to the second portion 620, and the driving assembly 300 can drive the connection block 600 to move in the second direction. The first portion 610 is connected to a slider 700, and a slide rail 800 is provided on the base 510 of the support assembly 500. The slide rail 800 extends along the second direction, and the slider 700 slidably cooperates with the slide rail 800 to realize the sliding of the connection block 600 on the base 510. The third part 630 is provided with a first elongated hole 631 extending in the first direction. The fixing member passes through the first elongated hole 631 and is connected to the abutment member 210 driven to move by the driving assembly 300. By setting the connecting block 600 to include the first part 610, the second part 620 and the third part 630, it is convenient to connect the connecting block 600 with the slider 700, and it is also convenient to connect the abutment member 210 with the connecting block 600, and it is convenient to connect the connecting block 600 with the driving assembly 300 without interfering with each other. In this embodiment, the size of the second part 620 in the first direction is smaller than the size of the third part 630 in the first direction, so that the connecting block 600 can be inserted into the support frame 520, and then the distance between the two abutment members 210 can be smaller, which can be suitable for wearable headphones of smaller size. In this embodiment, the fixing member can be a bolt.

[0068] Alternatively, if Figure 2 and Figure 3 As shown, the position detection component 400 is adjustably arranged on the base 510 of the support component 500 along the second direction. In this embodiment, the position detection component 400 is arranged on the side of the connecting block 600 away from the support frame 520. The position of the position detection component 400 on the base 510 is adjustable, so that the position detection component 400 can be used to detect different models of headphones and has a large application range. For example, the position detection component 400 can be arranged on a support, and the base 510 is provided with a fifth elongated hole 512 extending along the second direction. The bolt passes through the fifth elongated hole 512 from the bottom of the base 510 and is connected to the threaded hole on the support to achieve the connection between the base 510 and the support.

[0069] It should be noted that, when one of the two abutment members 210 is stationary and the other abutment member 210 moves under the drive of the driving component 300, the position detection component 400 is arranged on the side of the other abutment member 210 away from the one abutment member 210, and the position detection component 400 has a detection position. It is only necessary to determine whether the one abutment member 210 reaches the detection position to determine whether the clamping force of the headset meets the requirements.

[0070] Optionally, the drive assembly 300 includes a pressure regulating system, a cylinder 310 and a pressure detection member. The pressure regulating system is used to input gas into the cylinder 310. For example, the pressure regulating system may include a pressure regulating valve and a gas storage barrel. In this embodiment, the cylinder 310 has two air inlets, and the pressure regulating system selectively connects one of the air inlets. For example, a manual switching valve may be provided between the pressure regulating system and the air inlet of the cylinder 310. The manual switching valve is a one-in-two-out gas reversing switching valve, which is used to connect the pressure regulating system with different air inlets to achieve the forward and backward movement of the cylinder 310. The cylinder 310 is configured to drive the two abutments 210 away from each other, and the pressure detection member is configured to measure the gas pressure output by the pressure regulating system, thereby calculating the thrust output by the cylinder 310, which is the force exerted on the headphone. For example, the pressure detection member may be a gauge pressure gauge.

[0071] For example, the clamping force testing device further includes a digital output / output and analog input acquisition card (DO / DI analog), which is configured to simultaneously receive the digital signal output by the photoelectric sensor switch and the analog signal output by the pressure detection element.

[0072] When the clamping force testing device provided in this embodiment is used:

[0073] Fixed air intake pressure, fixed forward pushing speed of cylinder 310: To solve the problem of unstable speed of human-powered external earphone, a stable air pressure source is used to stabilize the pushing speed of cylinder 310 providing thrust, so that the speed of each external earphone stroke is fixed. To verify this idea, a camera is used to record the pushing process of cylinder 310, which is repeated 5 times in total, with 30 frames per second of video. The travel distance is divided by the recording time to convert the travel speed of cylinder 310 (cm / s), and the slow and fast conditions are recorded respectively. As shown in Table 2, when the average propulsion speed is 9.97cm / s, the maximum difference is 3.52%; when the average speed is 43.85cm / s, the speeds are consistent for 5 times.

[0074] Table 2

[0075]

[0076] The principle of the clamping force testing device provided in this embodiment is to adjust the thrust of the fixed cylinder forward through the pressure regulating system:

[0077] The formula for cylinder thrust is:

[0078] P×A×C=F, where P represents the cylinder intake pressure (Newton per square meter); A represents the cylinder cross-sectional area (square meters); C represents the cylinder efficiency coefficient (0.05~0.95); and F represents the thrust (N).

[0079] From the above formula, we can know that under the same cylinder condition (C is fixed), the fixed air pressure can be used to obtain the thrust of the fixed cylinder.

[0080] Moreover, it can be known from the above formula that even if the cylinders are of the same brand and type, their efficiency coefficient C will inevitably have individual differences. Even under the same individual conditions, with tens of thousands of cylinder reciprocating strokes and consumption, their efficiency coefficient will change with time. Therefore, this clamping force test device needs to be regularly traced and corrected like most instruments. Specifically, a portable force gauge can be used as a true value transmission part to trace back to the tensile testing machine, and the standard clamping force true value can be transmitted to this clamping force test device in sequence, so that the cylinder thrust true value in the system can be corrected according to the actual situation.

[0081] Measured results: The clamping force testing device provided in this embodiment was benchmarked against an experimental-grade tensile testing machine (INSTRON / 3367), and a headphone model of DELL WI5022A was used as a comparison piece. Under the condition of a fixed external tension distance of 150mm, the test was repeated ten times and the results were: the repeatability error can be controlled within ±1.0%, and the accuracy error is less than 1.5%.

[0082] Advantages of the clamping force testing device provided in this embodiment:

[0083] (1) Improve the poor repeatability of existing equipment due to the mechanism design by using linear direct push, reducing it from ±10% to ±1.0%;

[0084] (2) In this embodiment, low-pressure gas is used as the power source. The fixed gas pressure can make the cylinder thrust fixed. The cylinder and the existing slide rail mechanism are matched to obtain a fixed speed thrust. When measuring the clamping force of the headset, the repeatability error caused by the non-fixed external expansion speed and thrust of the plastic material of the headset headband is eliminated;

[0085] (3) Improved accuracy: The force gauge was traced back to the experimental tensile testing machine. After benchmarking verification, the accuracy error was reduced from 20% to 1.3%.

[0086] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. The clamping force testing device is characterized in that: include: A product fixing assembly (100), wherein the product fixing assembly (100) is provided with a slot (101) with adjustable width; A contact assembly (200) comprising two contact members (210) arranged on both sides of the product fixing assembly (100), wherein the contact members (210) are configured to contact the stretched part of the product to be tested; A driving assembly (300), wherein the driving assembly (300) is configured to drive at least one of the two abutting members (210) to move so that the distance between the two abutting members (210) is adjustable; and A position detection component (400) is configured to detect the distance between the two abutment members (210).

2. The clamping force testing device according to claim 1, characterized in that: The product fixing assembly (100) comprises a fixing rod (110) and two limiting members (120) sleeved on the fixing rod (110); the position of each limiting member (120) in the axial direction of the fixing rod (110) is adjustable; the two limiting members (120) and the fixing rod (110) cooperate to form the clamping groove (101).

3. The clamping force testing device according to claim 1, characterized in that: The clamping force testing device further comprises a supporting assembly (500), and the product fixing assembly (100) is arranged on the supporting assembly (500) in an adjustable manner along a first direction.

4. The clamping force testing device according to claim 3, characterized in that: The support assembly (500) comprises a base (510) and a support frame (520), wherein the support frame (520) is arranged on the base (510) in an adjustable manner along the second direction, and the product fixing assembly (100) is arranged on the support frame (520) in an adjustable manner along the first direction.

5. The clamping force testing device according to claim 4, characterized in that: One of the two abutment members (210) is connected to the drive assembly (300), and the other abutment member (210) is arranged on the support frame (520).

6. The clamping force testing device according to any one of claims 1 to 5, characterized in that: The clamping force testing device further comprises a support assembly (500), and the two abutment members (210) are both arranged on the support assembly (500) in an adjustable manner along a first direction; The driving component (300) drives one of the two abutting members (210) to move closer to or away from the other, and the abutting member (210) driven by the driving component (300) is slidably disposed on the supporting component (500) along a second direction.

7. The clamping force testing device according to claim 6, characterized in that: The clamping force testing device further comprises a connecting block (600), wherein the connecting block (600) is slidably connected to the supporting assembly (500) and is connected to the output end of the driving assembly (300), and the abutment member (210) driven to move by the driving assembly (300) is adjustably arranged on the connecting block (600) along the first direction.

8. The clamping force testing device according to claim 7, characterized in that: The connecting block (600) comprises a first part (610) and a second part (620) and a third part (630) connected to the same side of the first part (610); the output end of the driving component (300) is connected to the second part (620); the first part (610) is connected to a slider (700); a slide rail (800) is provided on the supporting component (500); the slider (700) is slidably matched with the slide rail (800); the third part (630) is provided with a first elongated hole (631) extending along the first direction; a fixing member passes through the first elongated hole (631) and is connected to the abutment member (210) driven to move by the driving component (300).

9. The clamping force testing device according to any one of claims 1 to 5, characterized in that: The position detection component (400) is arranged on the support component (500) in an adjustable manner along the second direction.

10. The clamping force testing device according to any one of claims 1 to 5, characterized in that: The driving assembly (300) comprises a pressure regulating system, a cylinder (310) and a pressure detecting component. The pressure regulating system is configured to input gas into the cylinder (310), the cylinder (310) is configured to drive the two abutting members (210) to move away from each other, and the pressure detecting component is configured to measure the gas pressure output by the pressure regulating system.

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