Device and method for testing volume compression ratio of rubber block

Abstract

The invention provides a rubber block volume compression ratio test device and test method, and belongs to the field of rubber detection. The pressure head is arranged right above the base; the oil pool is filled with oil and is used for placing a to-be-tested sample; the pressing head vertically moves relative to the base, the bottom end of the pressing head is inserted into the oil pool and isolates the oil pool from the outside, a channel is formed in the pressing head, one end of the channel penetrates through the bottom end face of the pressing head, the other end of the channel penetrates through the peripheral wall of the pressing head and communicates with the outside, and the channel is used for discharging air in the oil pool; the displacement sensor is used for detecting the vertical movement distance of the pressure head. The volume change rate of the rubber block immersed in oil under certain oil pressure is measured by adopting a comparison method, the travel distance of the pressure head is measured when oil pressure is applied to the rubber block and the metal block respectively to reach specified pressure intensity, and the volume change rate of the compressed rubber block can be calculated through the travel difference value of the two travel distances.

Description

Technical Field

[0001] This invention relates to the field of rubber testing technology, and in particular to a rubber block volume compressibility testing device and testing method. Background Technology

[0002] Currently, domestic and international research on the determination of the volume change rate of rubber immersed in oil mainly focuses on improving the testing methods for rubber volume change in order to improve the reliability and comparability of test results. However, directly measuring the volume change during compression is quite difficult. Summary of the Invention

[0003] In view of this, the present invention proposes a rubber block volume compression ratio testing device and testing method to solve the problem that it is currently difficult to directly measure the volume change in the compression of rubber blocks.

[0004] The technical solution of this invention is implemented as follows: This invention provides a rubber block volume compressibility testing device, including a base with an oil pool inside, the top of which is open; a pressure head positioned directly above the base; and a displacement sensor positioned on the side of the pressure head. The oil pool contains oil and is used to hold the test sample. The pressure head moves vertically relative to the base, with its bottom end inserted into the oil pool, isolating the oil pool from the outside. A channel is provided inside the pressure head, one end of which penetrates the bottom surface of the pressure head, and the other end of which penetrates the outer peripheral wall of the pressure head and connects to the outside. The channel is used to expel air from inside the oil pool. The displacement sensor is used to detect the vertical movement distance of the pressure head.

[0005] Based on the above technical solutions, preferably, it also includes a three-way pipe connected to the outer peripheral wall of the pressure head and connected to one end of the channel that passes through the outer peripheral wall of the pressure head; a valve connected to the three-way pipe and used to close the channel after the air in the oil tank is exhausted; and an oil pressure gauge connected to the three-way pipe and used to detect the internal pressure of the oil tank.

[0006] More preferably, it also includes a downward pressure output end, which is located directly above the pressure head and is used to apply downward pressure to the pressure head; wherein, a hemispherical groove is formed on the top surface of the pressure head, and the end of the downward pressure output end that contacts the pressure head is a ball head; when the downward pressure output end pushes the pressure head downward, the groove abuts against the ball head.

[0007] Based on the above technical solutions, preferably, it also includes several sealing rings, which are arranged sequentially on the inner peripheral wall of the oil tank near the top; wherein, when the pressure head is inserted into the oil tank, the sealing rings fill the space between the outer peripheral wall of the pressure head and the inner peripheral wall of the oil tank and seal it.

[0008] More preferably, the inner diameter of the oil sump is not less than the outer diameter of the pressure head, and the vertical depth of the oil sump is greater than the length of the pressure head entering the oil sump.

[0009] More preferably, the outer edge of the end of the pressure head that presses down toward the oil tank is a conical surface.

[0010] Based on the above technical solutions, preferably, it also includes several guide rods, which are arranged between the pressure head and the base; wherein, the several guide rods are arranged around the oil tank, one end of the guide rod is connected to the base and the other end passes through the pressure head and extends vertically upward.

[0011] On the other hand, the present invention also provides a method for testing the volumetric compressibility of a rubber block, using the aforementioned rubber block volumetric compressibility testing device, comprising the following steps: Step 1, after placing the test sample into an oil tank, injecting liquid into the oil tank until the test sample is submerged, manually inserting the bottom of the pressure head into the oil tank, first allowing air bubbles to precipitate in the oil tank by standing, and then pre-pressuring the pressure head to expel the air inside the oil tank; Step 2, zeroing the displacement sensor, and using the downward pressure output end to push the pressure head to apply pressure to the inside of the oil tank; Step 3, stopping the downward pressure output end when the oil pressure gauge detects that the pressure inside the oil tank has reached the desired value, and recording the value of the displacement sensor at this time.

[0012] Based on the above technical solutions, preferably, the test sample is a rubber block or a metal block of the same size, and the volume compression ratio of the rubber block sample is calculated by comparing the difference in the stroke of the indenter in the compression test of the metal block and the compression test of the rubber block.

[0013] Furthermore, the formula for calculating the volumetric compressibility of the rubber block is A=D. 2 (H) x -H j ) / d 2 h×100%, where D is the inner diameter of the oil tank, and H j H represents the displacement sensor's detection value when the test sample is a metal block. x d is the detection value of the displacement sensor when the test sample is a rubber block, h is the outer diameter of the test sample, and h is the thickness of the test sample.

[0014] The rubber block volume compressibility testing device and method of the present invention have the following advantages over the prior art: This invention employs a comparative method to determine the volume change rate of a rubber block immersed in oil under a certain oil pressure. The comparative sample is a metal block of identical size. Considering that the metal block has much greater stiffness than the rubber block, under the same test conditions, the travel distance of the indenter differs when oil pressure is applied to the rubber block and the metal block to reach a specified pressure. Assuming the metal block's volume does not compress, the additional travel distance of the indenter during the rubber block test compared to the metal block test can be used to calculate the compressed volume of the rubber block. This method effectively solves the technical problem of the inability to directly measure the volume of the rubber block during closed compression processes. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a perspective view of the test apparatus of the present invention; Figure 2 This is a side sectional view of the test apparatus of the present invention.

[0017] In the diagram: 1. Base; 101. Oil tank; 2. Pressure head; 201. Channel; 202. Groove; 3. Displacement sensor; 4. T-pipe; 5. Valve; 6. Oil pressure gauge; 7. Downward pressure output end; 8. Sealing ring; 9. Guide rod. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0024] like Figure 1 As shown, combined with Figure 2 The present invention provides a rubber block volume compression ratio testing device, comprising a base 1, an indenter 2, and a displacement sensor 3.

[0025] The base 1 is a cylindrical structure with a frustum at the top that expands outwards. An oil tank 101 is located inside the base 1; the oil tank 101 is cylindrical and open at the top. The oil tank 101 contains oil and is used to hold the test sample. The test sample is typically a standard-sized flat cylindrical block or a square-cylindrical block.

[0026] The pressure head 2 is positioned directly above the base 1. The pressure head 2 is also cylindrical and is typically fitted into a movable disc-shaped seat that can be raised and lowered. The pressure head 2 moves vertically relative to the base 1. The bottom end of the pressure head 2 is inserted into the oil tank 101, isolating the oil tank 101 from the outside. A channel 201 is provided inside the pressure head 2. One end of the channel 201 penetrates the bottom end face of the pressure head 2, and the other end of the channel 201 penetrates the outer peripheral wall of the pressure head 2 and connects to the outside. The channel 201 is used to discharge the air inside the oil tank 101.

[0027] The displacement sensor 3 can be a grating ruler, which is mounted on the side of the pressure head 2 by a fixed bracket and moves synchronously with the pressure head 2; the displacement sensor 3 is used to detect the vertical movement distance of the pressure head 2.

[0028] When conducting the experiment using the above technical solution, the sample to be tested is first placed in the oil tank 101, and then oil is injected into the oil tank 101 to submerge the sample. At this time, the sample is in a hydraulic pressure environment with zero oil pressure. Then, the pressure inside the oil tank 101 is increased by inserting the pressure head 2 into the oil tank 101 and pressing down. During the pressurization process, air inside the oil tank 101 is discharged through the channel 201. When the pressure inside the oil tank 101 reaches the desired pressure value, the sample is in the expected hydraulic pressure environment, and the sample will undergo volume compression in this hydraulic pressure environment. The downward stroke of the pressure head 2 detected by the displacement sensor 3 reflects the volume compression change of the sample. This embodiment uses the above method to determine the volume change rate of a rubber block immersed in oil under a certain oil pressure using a comparative method. The comparative test specimens are metal blocks of identical size. Considering that the metal block has much greater stiffness than the rubber block, under the same test conditions, the stroke traveled by the indenter differs when oil pressure is applied to the rubber block and the metal block to reach the specified pressure. Assuming that the volume of the metal block is not compressed, the additional stroke traveled by the indenter during the rubber block test compared to the metal block test can be used to calculate the compressed volume of the rubber block. This method effectively solves the technical problem that the volume of the rubber block cannot be directly measured during closed compression processes.

[0029] exist Figure 1 In one embodiment shown, a three-way pipe 4, a valve 5, and an oil pressure gauge 6 are also included.

[0030] The three-way pipe 4 is connected to the outer peripheral wall of the pressure head 2 and is connected to one end of the channel 201 that penetrates the outer peripheral wall of the pressure head 2. Generally, a threaded interface is set at the outer end of the channel 201 on the outer peripheral wall of the pressure head 2, and then one end of the three-way pipe is screwed to the interface.

[0031] Valve 5 is connected to the tee pipe 4. The function of valve 5 is to close valve 5 after the air in oil tank 101 has been purged, thereby sealing off channel 201 and isolating the inside of oil tank 101 from the outside.

[0032] The oil pressure gauge 6 is a standard pressure testing device. It is connected to the tee pipe 4 and used to test the internal pressure of the oil tank 101 to determine whether the internal pressure of the oil tank 101 has reached the expected value.

[0033] exist Figure 1In one embodiment shown, a downward pressure output terminal 7 is also included. The downward pressure output terminal 7 is an output terminal component of the stamping equipment. The pressure head 2 is located directly below the downward pressure output terminal 7. During the test, the downward pressure output terminal 7 will push down and push the pressure head 2, applying downward pressure to the pressure head 2, thereby causing the pressure head 2 to move downward in the oil tank 101 to gradually increase the internal pressure of the oil tank 101. A hemispherical groove 202 is provided on the top surface of the pressure head 2, and the end of the pressure output end 7 that contacts the pressure head 2 is a ball head; when the pressure output end 7 pushes the pressure head 2 downward, the groove 202 abuts against the ball head; the reason for adopting this design is that, in order to prevent the downward pressure from causing eccentricity, the pressure output end 7 of the stamping equipment is designed to be disconnected from the pressure head 2, and the pressure head 2 is not directly connected through the pressure output end 7 to press down. Therefore, the contact surface between the two, that is, the inner wall surface of the groove 202, is spherical, so that when the pressure output end 7 applies downward pressure to the pressure head 2, the pressure head 2 always maintains a balanced and stable downward pressure, and will not be displaced relative to the center of the oil tank 101.

[0034] exist Figure 1 In one embodiment shown, a plurality of sealing rings 8 are also included. The sealing rings 8 can be rubber O-rings, and multiple upper and lower sealing rings 8 are sequentially arranged on the inner peripheral wall of the oil tank 101 near the top. When the pressure head 2 is inserted into the oil tank 101, the sealing rings 8 fill the space between the outer peripheral wall of the pressure head 2 and the inner peripheral wall of the oil tank 101, thus sealing the oil tank 101 in conjunction with the pressure head 2 and generating oil pressure inside the oil tank 101 without causing oil pressure leakage.

[0035] exist Figure 1 In one embodiment shown, the inner diameter of the oil sump 101 is not less than the outer diameter of the pressure head 2, and the vertical depth of the oil sump 101 is greater than the length of the pressure head 2 entering the oil sump 101, so that the pressure head 2 can be accurately and smoothly inserted into the oil sump 101 and generate oil pressure in the oil sump 101.

[0036] exist Figure 1 In one embodiment shown, the outer edge of the end of the pressure head 2 that presses down toward the oil tank 101 is a conical surface, and the bottom of the conical surface is rounded and chamfered. The purpose is that when the pressure head 2 is compressed downward and enters the oil tank 101, the end of the pressure head 2 will not damage the O-ring 8 at the top of the inside of the oil tank 101.

[0037] exist Figure 1 In one embodiment shown, a guide rod 9 is also included. A plurality of guide rods 9 are disposed between the pressure head 2 and the base 1; the plurality of guide rods 9 are arranged around the oil tank 101, one end of the guide rod 9 is connected to the base 1 and the other end extends vertically upward through the pressure plate-shaped movable seat of the pressure head 2, and the function of the guide rod 9 is to guide the pressure head 2 to move vertically downward and insert into the oil tank 101.

[0038] like Figure 1 As shown, combined with Figure 2 This invention discloses a method for testing the volumetric compressibility of a rubber block, using the aforementioned rubber block volumetric compressibility testing device. The method includes the following steps: Step 1: After placing the test sample into an oil tank 101, oil is injected into the oil tank 101 until the sample is submerged. The bottom of the pressure head 2 is manually inserted into the oil tank 101. Air bubbles are first precipitated in the oil tank 101 by allowing it to settle. Then, the air inside the oil tank 101 is emptied by pre-pressurizing the pressure head 2. The pre-pressurization should be sufficient; when oil is continuously gushing out of the valve port, the valve should be quickly closed. Step 2: The displacement sensor 3 is zeroed, and the pressure output terminal 7 is used to push the pressure head 2 to apply pressure into the oil tank 101. Step 3: The pressure output terminal 7 is stopped when the oil pressure gauge 6 detects that the pressure inside the oil tank 101 has reached the desired value. The value of the displacement sensor 3 at this time is recorded. During data acquisition, LabVIEW programming is used to synchronously acquire data from the oil pressure gauge 6 and the displacement sensor 3. After the test is completed, since the pressure head 2 has entered the oil tank 101 to a certain depth and is tightly stuck by the O-ring 8, the valve 5 can be opened to release the pressure, and then the base 1 can be fixed and the pressure head 2 can be pushed out by the lifting device.

[0039] exist Figure 1 In one embodiment shown, the test sample is either a rubber block or a metal block of the same size. The volumetric compression ratio of the rubber block sample is calculated by comparing the difference in the stroke of the indenter 2 in the compression test of the metal block and the compression test of the rubber block. The principle is as follows: Under the same test conditions, when oil pressure is applied to the rubber block and the metal block to reach the specified pressure, the stroke traveled by the indenter 2 is different. Assuming that the volume of the metal block is not compressed, the extra stroke traveled by the indenter in the rubber block test compared to the metal block test can be used to calculate the compressed volume of the rubber block.

[0040] exist Figure 1 In one embodiment shown, the formula for calculating the volumetric compressibility of the rubber block is A=D. 2 (H) x -H j ) / d 2 h×100%, where D is the inner diameter of oil tank 101, H j H represents the detection value of displacement sensor 3 when the test sample is a metal block. x d represents the detection value of displacement sensor 3 when the test sample is a rubber block, h represents the outer diameter of the test sample, and d represents the thickness of the test sample. The compression displacement value H of the grating ruler was recorded in both experiments. x and H j Since the metal block has high stiffness, its compression is negligible compared to the rubber block. Assuming the metal block is not compressed, the compressed volume of the rubber block is 0.25πD. 2 (H x -H j), thus converting to obtain this calculation formula.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for testing the volumetric compressibility of a rubber block, characterized in that, include: The base (1) has an oil tank (101) inside, and the top of the oil tank (101) is open. The pressure head (2) is positioned directly above the base (1); A displacement sensor (3) is disposed on the side of the pressure head (2); The oil tank (101) contains oil and is used to hold the test sample. The pressure head (2) moves vertically relative to the base (1). The bottom end of the pressure head (2) is inserted into the oil tank (101) and isolates the oil tank (101) from the outside. A channel (201) is provided inside the pressure head (2). One end of the channel (201) penetrates the bottom end face of the pressure head (2), and the other end of the channel (201) penetrates the outer peripheral wall of the pressure head (2) and is connected to the outside. The channel (201) is used to discharge the air inside the oil tank (101). The displacement sensor (3) is used to detect the vertical movement distance of the pressure head (2).

2. The rubber block volume compressibility testing device according to claim 1, characterized in that, Also includes: A three-way pipe (4) is connected to the outer peripheral wall of the pressure head (2) and is connected to one end of the channel (201) that penetrates the outer peripheral wall of the pressure head (2); A valve (5) is connected to the tee pipe (4) and is used to close the passage (201) after the air in the oil sump (101) has been drained. An oil pressure gauge (6) is connected to the three-way pipe (4) and is used to detect the internal pressure of the oil sump (101).

3. The rubber block volume compressibility testing device according to claim 2, characterized in that, Also includes: The downward pressure output terminal (7) is located directly above the pressure head (2) and is used to apply downward pressure to the pressure head (2); The pressure head (2) has a hemispherical groove (202) on its top surface, and the end of the pressure head (2) that contacts the pressure head (2) is a ball head; when the pressure head (2) is pushed down by the pressure output end (7), the groove (202) abuts against the ball head.

4. The rubber block volume compressibility testing device according to claim 1, characterized in that, Also includes: Several sealing rings (8) are arranged sequentially in the upper and lower positions on the inner peripheral wall of the oil tank (101) near the top. When the pressure head (2) is inserted into the oil tank (101), the sealing ring (8) fills the space between the outer peripheral wall of the pressure head (2) and the inner peripheral wall of the oil tank (101) and seals it.

5. The rubber block volume compressibility testing device according to claim 4, characterized in that: The inner diameter of the oil tank (101) is not less than the outer diameter of the pressure head (2), and the vertical depth of the oil tank (101) is greater than the length of the pressure head (2) entering the oil tank (101).

6. The rubber block volume compressibility testing device according to claim 4, characterized in that: The outer edge of the end of the pressure head (2) that presses down toward the oil tank (101) is a conical surface.

7. The rubber block volume compressibility testing device according to claim 1, characterized in that, Also includes: Several guide rods (9) are disposed between the pressure head (2) and the base (1); Among them, several guide rods (9) are arranged around the oil tank (101), one end of the guide rod (9) is connected to the base (1) and the other end extends vertically upward through the pressure head (2).

8. A method for testing the volumetric compressibility of a rubber block, characterized in that: The rubber block volume compression ratio testing device according to claim 3 includes the following steps: Step 1: After placing the test sample into the oil tank (101), pour oil into the oil tank (101) until the test sample is submerged. Manually operate the bottom of the pressure head (2) to insert into the oil tank (101). First, let the sample stand in the oil tank (101) to precipitate air bubbles. Then, use the pressure head (2) to pre-pressurize and empty the air inside the oil tank (101). Step 2: Zero the displacement sensor (3) and use the downward pressure output terminal (7) to push the pressure head (2) to apply pressure to the inside of the oil tank (101); Step 3: Stop pressing down the output terminal (7) until the oil pressure gauge (6) detects that the internal pressure of the oil tank (101) has reached the expected value, and record the value of the displacement sensor (3) at this time.

9. The method for testing the volumetric compressibility of a rubber block according to claim 8, characterized in that: The test samples are rubber blocks or metal blocks of the same size, and the volume compression ratio of the rubber block sample is calculated by comparing the difference in the stroke of the indenter (2) in the metal block compression test and the rubber block compression test.

10. The method for testing the volumetric compressibility of a rubber block according to claim 9, characterized in that: The formula for calculating the volumetric compressibility of a rubber block is: A=D 2 (H x -H j ) / d 2 h×100%, Where D is the inner diameter of the oil tank (101), and H j H is the detection value of the displacement sensor (3) when the test sample is a metal block. x d is the detection value of the displacement sensor (3) when the test sample is a rubber block, h is the outer diameter of the test sample, and h is the thickness of the test sample.

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