Rubber product elasticity testing device and testing method

Abstract

The present invention relates to the technical field of rubber product testing, and specifically to a rubber product elasticity testing device and testing method, the rubber product elasticity testing device comprising: a testing machine, the testing machine being provided with a driving mechanism and a bearing platform; a bottom mold being locked on the bearing platform, a loading slot being provided inside the bottom mold, the loading slot being used for interference fitting a test object; a constant pressure portion being fixedly installed at the output end of the driving mechanism; the top of the bottom mold being designed as an open channel, the constant pressure portion being able to enter the channel and apply axial pressure to the test object; a metering structure for detecting the reset height of the test object being installed at the inner top of the bottom mold, a reaction chamber being further provided inside the bottom mold, the reaction chamber being connected to the inner bottom at the circumferential edge of the loading slot, the device of the present invention being capable of both testing the elastic recovery ability of rubber products and monitoring rubber products that have undergone rubber creep.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber product testing, and in particular to a rubber product elasticity testing device and a testing method. Background Art

[0002] Rubber products refer to various products made from natural or synthetic rubber. These products are widely used in various fields such as industry, agriculture, national defense, transportation, machinery manufacturing, medical care, and daily life due to the excellent properties of rubber materials, such as elasticity, wear resistance, corrosion resistance, insulation, and vibration resistance.

[0003] Some rubber products need to withstand repeated stretching and recovery for a long time during use. To cope with such working conditions, they need to have good elasticity and durability, such as rubber belts, rubber shock absorbers, sealing rings and elastic gaskets. Therefore, rubber products need to be tested for their elasticity before being put into use, especially their recovery ability. Rubber products such as rubber gaskets and shock absorbers need to undergo reciprocating compression and recovery. Summary of the Invention

[0004] The present invention provides a rubber product elasticity detection device, which can detect the elastic recovery ability of the rubber product and monitor the rubber product with rubber creep.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A rubber product elasticity testing device, comprising:

[0007] A testing machine, wherein the testing machine is provided with a driving mechanism and a bearing platform;

[0008] A bottom mold is locked on the carrying platform, and a loading slot is provided inside the bottom mold for interference fitting the test object;

[0009] A constant pressure portion is fixedly mounted on the output end of the driving mechanism;

[0010] The top of the bottom mold is designed as an open channel, and the constant pressure part can enter the channel and apply axial pressure to the test object;

[0011] A metering structure for detecting the reset height of the test object is installed on the inner top of the bottom mold.

[0012] Optionally, a reaction chamber is further provided inside the bottom mold, and the reaction chamber is connected to the inner bottom at the circumferential edge of the loading slot. When the test object is interference fit in the loading slot, the test object isolates the connection between the reaction chamber and the loading slot, and the inside of the reaction chamber is negative pressure.

[0013] Optionally, multiple adaptive cylinders are installed on the top of the bottom mold, and an annular limit plate is commonly installed on the output end of the adaptive cylinder. The outer edge of the annular limit plate can slide like a piston with the inner wall of the loading slot. Under the drive of the adaptive cylinder, the bottom of the annular limit plate always conflicts with the top of the test object.

[0014] Optionally, the measuring structure includes a measuring rod fixedly mounted on an annular limit plate, the measuring rod passing through the inner top of the bottom mold, and the outer wall of the measuring rod is marked with a measuring scale, the top of the measuring rod is a reflective surface, and the testing machine is equipped with a miniature laser rangefinder, which can measure the distance between the top of the measuring rod and the laser rangefinder.

[0015] Optionally, a guide column is fixedly installed on the inner bottom of the loading tank, and the test object can be sleeved on the outside of the guide column. A guide hole is opened on the constant pressure part, and the guide hole forms a guiding fit with the outer wall of the guide column.

[0016] Optionally, the outer wall of the guide column near the bottom end is covered with a flexible pressure sensing sheet, and the flexible pressure sensing sheet is composed of a flexible substrate, a conductive layer, a pressure-sensitive layer and a protective layer from the inside to the outside. The test object will be sleeved on the outer wall of the protective layer before testing, and the flexible pressure sensing sheet is associated with an external digital display system.

[0017] Optionally, the reaction chamber is divided into a plurality of identical micro-cavities, and an air pressure sensor is installed in each of the micro-cavities.

[0018] A method for detecting elasticity of a rubber product is implemented using the aforementioned rubber product elasticity detection device and an external negative pressure device, and the method comprises the following steps:

[0019] S1: Place the test object on the outer wall of the guide column and the flexible pressure sensor, and record the height of the top of the measuring rod;

[0020] S2: Turn on the testing machine, and enable the driving mechanism to drive the constant pressure part into the loading slot and reciprocately compress the top of the test object;

[0021] S3: After the preset number of compressions, the height of the top of the measuring rod is measured to test the recovery ability of the test object;

[0022] S4: Associating the negative pressure device with the reaction chamber to make the interior of the reaction chamber a negative pressure state, and using the air pressure sensor to detect the negative pressure state of the reaction chamber to detect whether rubber creep occurs in the test object.

[0023] Optionally, in S4, the step further includes:

[0024] V1: records the initial pressure value of the flexible pressure sensor;

[0025] V2: After rubber creep occurs, check whether the tightening force or internal stress of the test object on the flexible pressure sensing piece is relaxed.

[0026] Optionally, S1 also includes a self-test step:

[0027] T1: Connect the negative pressure device to the reaction chamber to create a negative pressure state inside the reaction chamber, and use the up and down displacement of the annular limit piece to put the test object into an interference fit state;

[0028] T2: The annular limit piece moves upward, releasing the resistance to the top of the test object and the inner wall of the loading tank, thus releasing the top of the test object;

[0029] T3: Detect the negative pressure state of the reaction chamber. If the negative pressure state of the reaction chamber remains unchanged, it is determined that the interference fit of the test object is normal and the subsequent rubber creep test steps can be carried out.

[0030] The present invention provides a rubber product elasticity detection device and detection method, which achieve the following beneficial effects:

[0031] 1. By designing the fit between the bottom die and the loading slot, the test object can be installed using an interference fit and can be limited in position. When the constant pressure part is controlled by the driving mechanism to move back and forth, the constant pressure part can apply axial pressure to the top of the test object, allowing the test object to cycle between compression and recovery. When the compression amount remains unchanged or the pressure is constant, when a certain number of compressions or compression cycles are reached, the elastic recovery ability of the test object can be determined by detecting the recovery height of the test object.

[0032] Second, because the reaction chamber is under negative pressure while the loading tank is under normal pressure, there is a pressure difference between the two. If the test object experiences rubber creep, its shape will change, causing the interference fit to fail. At this time, the loading tank and the reaction chamber will be connected, thus invalidating the negative pressure state of the reaction chamber, thereby determining whether the test object has experienced rubber creep.

[0033] 3. By monitoring the tightening force or stress applied by the test object to the flexible pressure sensing sheet, it is possible to determine whether stress relaxation occurs in the test object. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the external three-dimensional structure of the present invention;

[0035] Figure 2 Schematic diagram of the three-dimensional structure of the bottom mold and the metering structure of the present invention;

[0036] Figure 3 For the present invention Figure 2 Schematic diagram of the right view structure;

[0037] Figure 4 For the present invention Figure 3 Schematic diagram of the structure viewed from the AA position;

[0038] Figure 5 Schematic diagram of the three-dimensional half-section structure of the interior of the bottom mold of the present invention;

[0039] Figure 6 Schematic diagram of the external three-dimensional structure of the bottom mold of the present invention;

[0040] Figure 7 It is a schematic diagram of the three-dimensional structure of the guide column and the flexible pressure sensing sheet in the present invention.

[0041] In the figure: 1. Testing machine; 2. Bottom mold; 3. Constant pressure part; 4. Guide column; 5. Driving mechanism; 6. Reaction chamber; 7. Measuring rod; 8. Annular limit plate; 9. Adaptive cylinder; 11. Flexible pressure sensor. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] See also Figures 1 to 7 The present invention provides a technical solution: a rubber product elasticity detection device, comprising:

[0044] The testing machine 1 is provided with a driving mechanism 5 and a supporting platform; a bottom mold 2 is locked on the supporting platform, and a loading slot is provided inside the bottom mold 2, which is used for interference fitting the test object; a constant pressure part 3 is fixedly installed at the output end of the driving mechanism 5; the top of the bottom mold 2 is designed as an open channel, and the constant pressure part 3 can enter the channel and apply axial pressure to the test object; a metering structure for detecting the reset height of the test object is installed on the inner top of the bottom mold 2.

[0045] In the present invention, by designing the fit between the bottom mold 2 and the loading slot, the test object can be installed by utilizing interference fit, and the test object can be limited. When testing is required, the driving mechanism 5 is utilized to control the constant pressure portion 3 to move back and forth, thereby enabling the constant pressure portion 3 to apply axial pressure to the top of the test object, so that the test object can cycle between compression and recovery. When the compression amount remains unchanged or the pressure is constant, after reaching a certain number of compressions or compression cycles, by detecting the reset height of the test object, it can be determined whether the elastic recovery ability of the test object is destroyed or whether the elastic recovery ability is weakened, thereby effectively evaluating the elastic recovery ability of the rubber gasket and ensuring its reliability and durability in practical applications.

[0046] During the test, the environment needs to be controlled to ensure that the temperature and humidity of the test environment are stable to avoid the influence of environmental factors on the test results, and to ensure that the compression amount or pressure of the constant pressure part 3 on the test object is constant so that the test process can meet the test standards such as ASTMD395 and ISO815.

[0047] Among them, a more preferred embodiment is that a reaction chamber 6 is further opened inside the bottom mold 2, and the reaction chamber 6 is connected with the inner bottom at the circumferential edge of the loading tank. When the test object is interference fit in the loading tank, the test object isolates the communication between the reaction chamber 6 and the loading tank, and the inside of the reaction chamber 6 is negative pressure.

[0048] Repeated compression and recovery will cause rubber to creep. This is because under the repeated cyclic stress, the molecular chains of rubber materials will continue to slip and rearrange, gradually accumulating permanent deformation. As the number of cycles increases, the rubber will experience irreversible permanent deformation, gradually reducing thickness or changing shape. Therefore, it is necessary to monitor or inspect rubber creep. In this invention, please refer to Figure 4 In the normal state, the test object is interference-fitted in the loading tank. At this time, the test object in the initial state will use the interference fit as a partition to disconnect the reaction chamber 6 from the loading tank. When testing is required, since the reaction chamber 6 is in a negative pressure state and the loading tank is in a normal state, there is a pressure difference between the two. If the test object undergoes rubber creep, its shape will change, resulting in the failure of the interference fit. At this time, the loading tank and the reaction chamber 6 will be connected, thereby failing the negative pressure state of the reaction chamber 6, thereby determining whether the test object has undergone rubber creep. Even if rubber creep has not occurred, a deformation accident has occurred.

[0049] Furthermore, a plurality of adaptive cylinders 9 are installed on the top of the bottom mold 2. The output ends of the adaptive cylinders 9 are commonly installed with an annular limiting piece 8. The outer edge of the annular limiting piece 8 can slide like a piston with the inner wall of the loading groove. Under the drive of the adaptive cylinders 9, the bottom of the annular limiting piece 8 always conflicts with the top of the test object. Please refer to Figure 4In this embodiment, when the test object is compressed, the tracking action of the annular limit plate 8 can assist the constant pressure part 3 to complete the reciprocating compression action. When the test object returns to its original state, it will push the annular limit plate 8 upward, and the adaptive cylinder 9 can also feel the recovery stress of the test object.

[0050] Furthermore, the measuring structure includes a measuring rod 7 fixedly mounted on an annular limiting piece 8, the measuring rod 7 passes through the inner top of the bottom mold 2, and a measuring scale is marked on the outer wall of the measuring rod 7. The top of the measuring rod 7 is a reflective surface. A miniature laser rangefinder is installed on the testing machine 1, and the laser rangefinder can measure the distance between the top of the measuring rod 7 and the laser rangefinder. In this embodiment, since the annular limiting piece 8 will follow the displacement of the top of the test object, the measuring scale on the measuring rod 7 can display the height of the test object. An accurate digitally displayable measuring method is also designed, and the laser emitted by the laser rangefinder and the rebound path are used to determine the height of the measuring rod 7 and the test object. Specifically, when the elastic recovery ability of the test object weakens, the recovery time and recovery stroke of the test object will change. Since it is a compressive pressure, the elastic ability of the test object is reflected in its height or thickness. Therefore, the thickness or height change of the test object can be accurately and real-time detected by the laser rangefinder and the measuring rod 7.

[0051] Furthermore, a guide post 4 is fixedly installed on the inner bottom of the loading tank, and the test object can be sleeved on the outside of the guide post 4. A guide hole is opened on the constant pressure part 3, and the guide hole forms a guiding match with the outer wall of the guide post 4. The outer wall of the guide post 4 near the bottom is covered with a flexible pressure sensing sheet 11. The flexible pressure sensing sheet 11 is composed of a flexible substrate, a conductive layer, a pressure-sensitive layer and a protective layer on the inside and outside. The test object will be sleeved on the outer wall of the protective layer before testing, and the flexible pressure sensing sheet 11 is associated with the external digital display system. Please refer to Figure 4 、 Figure 6 and Figure 7 In this embodiment, when rubber creep occurs in the test object, stress relaxation will also occur synchronously. Under constant deformation, the internal stress of the test object gradually decreases over time, which will cause the fastening force of the test object to decrease, affecting its durability and reliability. That is, the fastening force or internal stress of the test object on the flexible pressure sensing piece 11. When the internal stress or fastening force is reduced, the pressure applied by the test object to the flexible pressure sensing piece 11 will also be reduced, so that the specific situation or early warning can be easily judged by the change in the pressure value of the flexible pressure sensing piece 11.

[0052] Furthermore, the reaction chamber 6 is divided into a plurality of identical micro chambers, each of which is equipped with an air pressure sensor, see Figure 5In this embodiment, when the test object undergoes rubber creep, its deformation will cause a gap to form between the axial outer wall of the test object and the inner wall of the loading slot, thereby enabling communication between the reaction chamber 6 and the loading slot. By designing multiple reaction chambers 6, the deformation position of the test object can be accurately located, narrowing the scope of investigation, which can be more helpful for inspection and judgment.

[0053] By utilizing the above structures, it is possible to detect the elastic recovery ability of rubber products and also to monitor rubber products that have undergone rubber creep.

[0054] A method for detecting elasticity of a rubber product, the method using a rubber product elasticity detection device and an external negative pressure device, the method comprising the following steps:

[0055] S1: Place the test object on the outer wall of the guide column 4 and the flexible pressure sensing sheet 11, and record the height of the top of the measuring rod 7;

[0056] S2: Turn on the testing machine 1, and enable the driving mechanism 5 to drive the constant pressure part 3 into the loading slot and reciprocately compress the top of the test object;

[0057] S3: After the preset number of compressions, the height of the top of the measuring rod 7 is measured to detect the recovery ability of the test object;

[0058] S4: Associating the negative pressure device with the reaction chamber 6 to make the interior of the reaction chamber 6 a negative pressure state, and using an air pressure sensor to detect the negative pressure state of the reaction chamber 6 to detect whether rubber creep occurs in the test object.

[0059] In the testing of rubber products, especially rubber gaskets and shock absorbers that require repeated compression and recovery, the recovery stroke and recovery strength of the rubber products are the most important. Therefore, in this method, the elastic recovery ability of the test object can be judged by measuring its height or thickness. Secondly, the isolation ability of the test object can also be used to determine whether rubber creep has occurred. The most obvious manifestation of rubber creep is the deformation of the rubber product.

[0060] Furthermore, in S4, it also includes:

[0061] V1: records the initial pressure value of the flexible pressure sensing sheet 11;

[0062] V2: After the rubber creep occurs, it is detected whether the tightening force of the test object on the flexible pressure sensing piece 11 or the internal stress is relaxed.

[0063] In this method, by comparing the front and rear pressure values ​​of the flexible pressure sensing sheet 11, it is possible to determine whether the internal stress applied by the test object to the flexible pressure sensing sheet 11 is weakened, and then determine whether the test object undergoes stress relaxation simultaneously after rubber creep.

[0064] Furthermore, in S1, a self-checking step is also included:

[0065] T1: Connect the negative pressure device to the reaction chamber 6 to create a negative pressure state inside the reaction chamber 6, and use the up and down displacement of the annular limit piece 8 to put the test object into an interference fit state;

[0066] T2: The annular limiting piece 8 moves upward, releasing the resistance to the top of the test object and the inner wall of the loading slot, thus releasing the top of the test object;

[0067] T3: Detect the negative pressure state of the reaction chamber 6. If the negative pressure state of the reaction chamber 6 remains unchanged, it is determined that the interference fit of the test object is normal, and the subsequent rubber creep test step can be performed.

[0068] In this method, the accuracy of the detection work can be ensured by self-testing the isolation capability of the test object.

[0069] By adopting the above method, the elastic recovery ability of the rubber product can be tested in a mold, and the creep of the rubber can also be monitored and the deformation position can be tracked.

[0070] The standard parts used in this embodiment can be purchased directly from the market, and the non-standard structural components recorded in the specification and drawings can also be directly processed according to existing technical common sense without any doubt. At the same time, the connection method of each component adopts the mature conventional means in the existing technology, and the machinery, parts and equipment all adopt conventional models in the existing technology, so no specific description is given here.

[0071] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A rubber product elasticity testing device, characterized by: include: A testing machine (1), wherein the testing machine (1) is provided with a driving mechanism (5) and a bearing platform; A bottom mold (2) is locked on the supporting platform, and a loading slot is provided inside the bottom mold (2), and the loading slot is used for interference fitting the test object; A constant pressure portion (3) is fixedly mounted on the output end of the driving mechanism (5); The top of the bottom mold (2) is designed as an open channel, and the constant pressure portion (3) can enter the channel and apply axial pressure to the test object; A metering structure for detecting the reset height of the test object is installed on the inner top of the bottom mold (2); A reaction chamber (6) is further provided inside the bottom mold (2), and the reaction chamber (6) is connected to the inner bottom of the loading tank at the peripheral edge. When the test object is interference-fitted in the loading tank, the test object isolates the communication between the reaction chamber (6) and the loading tank, and the interior of the reaction chamber (6) is negative pressure. A plurality of adaptive cylinders (9) are installed at the top of the bottom mold (2), and an annular limiting piece (8) is installed on the output end of the adaptive cylinder (9). The outer edge of the annular limiting piece (8) can slide with the inner wall of the loading groove in a piston-like manner. Under the drive of the adaptive cylinder (9), the bottom of the annular limiting piece (8) always contacts the top of the test object.

2. The rubber product elasticity testing device according to claim 1, characterized in that: The metering structure comprises a measuring rod (7) fixedly mounted on an annular limiting piece (8), the measuring rod (7) passing through the inner top of the bottom mold (2), and a measuring scale is marked on the outer wall of the measuring rod (7), the top of the measuring rod (7) being a reflective surface, and a miniature laser rangefinder is mounted on the testing machine (1), and the laser rangefinder is capable of measuring the distance between the top of the measuring rod (7) and the laser rangefinder.

3. The rubber product elasticity testing device according to claim 1, characterized in that: A guide column (4) is fixedly mounted on the inner bottom of the loading slot, and the test object can be sleeved on the outside of the guide column (4). A guide hole is opened on the constant pressure portion (3), and the guide hole forms a guiding fit with the outer wall of the guide column (4).

4. The rubber product elasticity testing device according to claim 3, characterized in that: The outer wall of the guide column (4) near the bottom end is covered with a flexible pressure sensing sheet (11), and the flexible pressure sensing sheet (11) is composed of a flexible substrate, a conductive layer, a pressure-sensitive layer and a protective layer from the inside to the outside. The test object will be sleeved on the outer wall of the protective layer before testing, and the flexible pressure sensing sheet (11) is associated with an external digital display system.

5. The rubber product elasticity testing device according to any one of claims 1 to 4, characterized in that: The reaction chamber (6) is divided into a plurality of identical micro-cavities, each of which is equipped with an air pressure sensor.

6. A method for testing the elasticity of a rubber product, the method being implemented using the rubber product elasticity testing device as claimed in claim 5 and an external negative pressure device, characterized in that: The detection method comprises the following steps: S1: The test object is placed on the outer wall of the guide column (4) and the flexible pressure sensing sheet (11), and the height of the top of the measuring rod (7) is recorded; S2: Turn on the testing machine (1), and make the driving mechanism (5) drive the constant pressure part (3) into the loading slot and reciprocately compress the top of the test object; S3: After the preset number of compressions, the height of the top of the measuring rod (7) is measured to detect the recovery ability of the test object; S4: Associating the negative pressure device with the reaction chamber (6) to make the interior of the reaction chamber (6) a negative pressure state, and using an air pressure sensor to detect the negative pressure state of the reaction chamber (6) to detect whether rubber creep occurs in the test object.

7. The method for detecting elasticity of a rubber product according to claim 6, wherein: In said S4, it further includes: V1: records the initial pressure value of the flexible pressure sensing sheet (11); V2: After the rubber creep occurs, it is detected whether the tightening force or internal stress of the test object on the flexible pressure sensing piece (11) is relaxed.

8. The method for detecting elasticity of a rubber product according to claim 7, wherein: In said S1, a self-test step is also included: T1: Associating the negative pressure device with the reaction chamber (6) so that the interior of the reaction chamber (6) is in a negative pressure state, and utilizing the up and down displacement of the annular limiting piece (8) to place the test object in an interference fit state; T2: the annular limiting piece (8) moves upward, releasing the resistance to the top of the test object and the inner wall of the loading tank, thereby releasing the top of the test object; T3: Detecting the negative pressure state of the reaction chamber (6). If the negative pressure state of the reaction chamber (6) remains unchanged, it is determined that the interference fit of the test object is normal, and the subsequent rubber creep test step can be carried out.

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