High-temperature friction clamp for friction test

Abstract

The utility model discloses a high-temperature friction clamp for a friction test, which comprises a base, a step arranged at the top of the base, a groove arranged at the center of the bottom surface of the step, a square sample fixing area used for placing a sample, fan-shaped oil storage cavities arranged at four corners of the groove, and an oil storage cavity arranged at the bottom of the groove. The fan-shaped oil storage cavity is communicated with the sample fixing area; a boss is arranged at the bottom of the cover body, an assembly gap is formed between the top surface of the boss and the bottom surface of the step, and an annular gap oil storage cavity is formed among the inner wall of the through hole, the upper surface of the sample and the friction probe. The annular gap oil storage cavity is formed among the inner wall of the through hole, the upper surface of the sample and the friction probe, so that a friction contact surface is always kept in a proper lubrication state, the sample is stably clamped in a high-temperature friction test, and meanwhile, continuous supply of lubricating oil is maintained through a built-in oil storage structure.

Description

Technical Field

[0001] This utility model relates to the field of fixture technology in friction testing, and in particular to a high-temperature friction fixture for friction testing. Background Technology

[0002] In manufacturing, friction testing is a commonly used quality control technique for accurately measuring the surface friction coefficient of workpieces. However, traditional friction measurement methods have several technical shortcomings: the design and use of fixtures often fail to consider the addition of lubricating oil, leading to deviations between test conditions and actual working conditions; typically, friction tests are conducted by directly adjusting the temperature without adding lubricating oil, which does not take into account the actual stamping process. Especially in stamping process simulation experiments, the accuracy of the friction coefficient is not only related to the process contact conditions at the node location, but also closely related to the lubrication state, lubrication amount, material type and properties of the sheet metal and die, coatings and surface treatments, and surface roughness.

[0003] Existing fixtures struggle to maintain stable lubrication under high-temperature conditions, impacting the reliability of measurement data. Traditional fixtures, lacking an oil reservoir structure, cannot simulate the lubrication environment under real-world operating conditions, leading to systematic errors between test results and actual production data. Utility Model Content

[0004] The purpose of this invention is to provide a high-temperature friction fixture for friction testing, so as to solve one or more technical problems existing in the prior art, or at least provide a beneficial option or create conditions.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: First, this utility model provides a high-temperature friction fixture for friction testing, comprising:

[0006] The base has a step at the top, and a groove is located at the center of the bottom surface of the step. The groove is a square-shaped sample fixing area for placing the sample. There are fan-shaped oil storage cavities at the four corners of the groove. The fan-shaped oil storage cavities are connected to the sample fixing area. The fan-shaped oil storage cavities are fan-shaped with a central angle greater than 180°. The depth of the fan-shaped oil storage cavities is the same as the groove depth.

[0007] The cover has a boss at the bottom and a through hole at the center of the boss. The through hole allows the friction probe of the friction testing machine to sink freely. There is an assembly gap between the top surface of the boss and the bottom surface of the step. The inner wall of the through hole forms an annular gap oil storage cavity between the upper surface of the sample and the friction probe.

[0008] This invention precisely constrains the horizontal displacement of the sample through grooves. A fixed amount of lubricating oil is injected into the four corner fan-shaped oil reservoirs before the test. Under high-temperature conditions, the oil expands due to heat and diffuses along the edge of the grooves to the friction contact surface. An annular gap oil reservoir is formed between the inner wall of the through-hole, the upper surface of the sample, and the friction probe, ensuring that the friction contact surface maintains appropriate lubrication at all times. This achieves stable clamping of the sample during high-temperature friction tests, while the built-in oil reservoir structure maintains a continuous supply of lubricating oil. The integrated design of the sample fixing area and the oil reservoir avoids the need for frequent interruptions to replenish oil required by traditional clamps, improving testing efficiency and data continuity.

[0009] As an extension of the above solution, the base is provided with a first mounting hole, which is distributed in a circumferential array around the center of the bottom surface of the step and located outside the groove. The cover is provided with a second mounting hole aligned with the first mounting hole, which is located outside the through hole. The first mounting hole and the second mounting hole are used to fix the cover to the base by bolt assembly.

[0010] In this extended design, during assembly, bolts pass sequentially through the second mounting hole of the cover and the first mounting hole of the base, and the cover and base are pressed and fixed together by tightening the bolts. Because the mounting holes are distributed in a circumferential array, the force on the cover and base is more even, avoiding localized stress concentration that could lead to fixture deformation.

[0011] As an extension of the above solution, the bolt passes through the second mounting hole from the top of the cover and exits through the first mounting hole of the base. The protruding end of the bolt locks with the positioning hole of the friction testing machine base, thus fixing the high-temperature friction fixture to the friction testing machine. This extended solution ensures the stability of the fixture during friction testing in a high-temperature environment, preventing sample position displacement due to vibration or thermal expansion. It solves the problem of sample position displacement caused by fixture loosening during high-temperature friction testing, ensuring that the contact surface of the sample remains stably aligned with the friction probe throughout the test, thereby improving the accuracy of the friction coefficient measurement results.

[0012] As an extension of the above solution, the fan-shaped oil reservoir is a 3 / 4 circle, with the center of the 3 / 4 circle coinciding with the vertex of the square shape of the groove. This extended solution, using a 3 / 4 circle design, increases oil storage capacity while maintaining structural strength, effectively solving the problem of insufficient lubrication at the corners of square samples. During high-temperature friction testing, it can maintain a continuous and uniform distribution of lubricant at the sample edges, avoiding measurement deviations in the coefficient of friction caused by local lubrication failure, and improving the accuracy and repeatability of experimental data.

[0013] As an extension of the above solution, the groove is provided with a groove liner, the outer wall of which fits against the inner wall of the groove. A square through-area is provided at the center of the groove liner, and third oil storage chambers are provided at the four corners of the square through-area. This extended solution solves the sample compatibility problem by adding a groove liner with oil storage chambers.

[0014] As an extension of the above solution, the bottom surface of the groove is provided with a magnetic element for magnetically attracting and fixing the groove liner to the groove. This extended solution achieves stable fixing and convenient replacement of the groove liner, solving the problem of easy displacement or loosening of the liner under high temperature conditions, thereby ensuring the stability of lubricating oil supply and improving the reliability and repeatability of friction test data.

[0015] As an extension of the above solution, the groove has a side length of 20mm and a depth of 1.2mm. This extended solution effectively adapts to standard sample sizes, and the sample surface is flush after insertion.

[0016] As an extension of the above solution, the sector-shaped oil reservoir has a sector radius of 1 mm and a depth of 1.2 mm. This extended solution uses sector-shaped oil reservoir parameters with a uniform depth, which simplifies machining and allows the oil to expand under high temperatures and diffuse along the edge of the groove to the friction contact surface, ensuring continuous lubrication.

[0017] As an extension of the above solution, the diameter of the through hole is 24.4 mm, and the gap between the inner wall of the through hole and the friction probe is 0.2 mm. This extended solution utilizes the 0.2 mm gap to lock in oil and prevent splashing, avoiding oil leakage, uneven oil film, or interference with the friction probe.

[0018] As an extension of the above solution, three first and three second assembly holes are provided, and the straight-line distance between the centers of the first assembly holes is 25mm. This 25mm straight-line distance effectively matches the standard interface of the friction testing machine's base, ensuring assembly compatibility. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0020] Figure 1 This is a schematic diagram of the high-temperature friction fixture in the embodiment;

[0021] Figure 2 This is an exploded structural diagram of the high-temperature friction fixture in the embodiment;

[0022] Figure 3 yes Figure 1 Schematic diagram of the cross-sectional structure along the AA direction;

[0023] Figure 4 This is a schematic diagram of the exploded structure of the high-temperature friction fixture with added groove pads in the embodiment.

[0024] In the attached diagram: 100: base, 110: step, 120: groove, 130: fan-shaped oil storage cavity, 140: first assembly hole, 150: groove gasket, 151: square through area, 152: third oil storage cavity, 200: cover, 210: boss, 220: through hole. Detailed Implementation

[0025] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0026] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 this utility model.

[0027] In the description of this utility model, if there are words such as "several", they mean one or more, "multiple" means two or more, "greater than", "less than", "exceeding" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself.

[0028] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0029] Reference Figures 1 to 4 The following are several embodiments of a high-temperature friction fixture for friction testing according to the present invention.

[0030] like Figures 1-3 As shown, in some embodiments, a high-temperature friction fixture for friction testing includes:

[0031] The base 100 has a step 110 at the top. A groove 120 is provided at the center of the bottom surface of the step 110. The groove 120 is a square-shaped sample fixing area for placing samples. Fan-shaped oil storage cavities 130 are provided at the four corners of the groove 120. The fan-shaped oil storage cavities 130 are connected to the sample fixing area. The fan-shaped oil storage cavities 130 are fan-shaped with a central angle greater than 180°. The depth of the fan-shaped oil storage cavities 130 is the same as the groove depth of the groove 120.

[0032] The cover 200 has a boss 210 at the bottom and a through hole at the center of the boss 210. The through hole is used for the friction probe of the friction testing machine to sink freely. There is an assembly gap between the top surface of the boss 210 and the bottom surface of the step 110. The inner wall of the through hole 220 forms an annular gap oil storage cavity between the upper surface of the sample and the friction probe.

[0033] In this embodiment, the base 100 refers to a rigid structural component supporting the sample, which can be cast from a high-temperature resistant alloy material. A stepped structure is used to achieve proper positioning with the cover 200. The groove 120 refers to a square area for accommodating the sample, which can be milled to form a standard-sized cavity. Its inner wall can fit with the edge of the sample, and the sample is mechanically fixed by the square boundary, meeting the basic positioning requirements. In some preferred embodiments, the side length of the groove 120 is 20mm, and the groove depth is 1.2mm, effectively adapting to the standard sample size, ensuring a flush surface after sample insertion.

[0034] The fan-shaped oil reservoir 130 refers to an arc-shaped groove for storing lubricating oil. Its arc design increases the oil storage capacity while avoiding interference with sample positioning. In some preferred embodiments, the fan-shaped oil reservoir has a radius of 1 mm and a depth of 1.2 mm. If the radius of the fan-shaped oil reservoir is too large, it will encroach on the sample fixing area; if it is too small, the oil storage will be insufficient. The depth is consistent with the groove depth of the groove 120. If there is a difference in depth between the two grooves, it will increase the processing cost. A uniform depth can simplify the processing. A fixed amount of lubricating oil is injected into the four corner fan-shaped oil reservoirs before the test. Under high temperature conditions, the oil expands due to heat and diffuses along the edge of the groove 120 to the friction contact surface continuously, ensuring continuous lubrication.

[0035] The cover 200 refers to a detachable component covering the base 100. Specifically, it can be designed as a split structure, with the boss 210 and step 110 positioned and engaged, and then bolted to the base 100 for fixation. A seal can be achieved between the boss 210 and step 110, such as through sidewall interference fit or by using existing sealing structures, ensuring the sealing of the oil stored in the groove 120 and preventing lubricant leakage. There is an assembly gap between the top surface of the boss 210 and the bottom surface of the step 110, preferably 0.05mm-0.1mm, for thermal expansion compensation.

[0036] The through-hole 220 refers to a circular channel that allows the friction probe to sink freely. The diameter of the hole can be slightly larger than the probe diameter to form a non-contact gap. In some preferred embodiments, the diameter of the through-hole 220 is 24.4 mm, and the gap between the inner wall of the through-hole 220 and the friction probe is 0.2 mm. This 0.2 mm gap helps to lock in oil and prevent splashing. If the through-hole diameter is too large, oil slinging will occur, meaning the gap is too wide and oil leakage will result. If the through-hole diameter is too small, interference with the friction probe will occur, and the narrow gap will result in an uneven oil film.

[0037] In existing technologies, friction testing is a crucial step in quality control during manufacturing, used to accurately measure the coefficient of friction of workpiece surfaces. Traditional friction fixtures typically focus only on sample fixation, neglecting the impact of lubrication conditions on the coefficient of friction during actual stamping. Frequent interruptions are required during testing to replenish lubricating oil, leading to discontinuous data acquisition and low testing efficiency. Furthermore, lubricating oil easily evaporates and is lost at high temperatures, making it difficult for traditional fixtures to maintain a stable lubrication state, thus affecting the accuracy of experimental results.

[0038] To address the aforementioned issues, it is first necessary to achieve stable sample fixation under high-temperature conditions, and secondly, to overcome the technical challenge of continuous lubrication supply. The lubrication state of the friction contact surfaces directly affects the reliability of the test data, and the lack of a lubrication storage structure in traditional fixtures leads to test conditions that do not match actual working conditions. Therefore, integrating a lubrication system within the fixture is a key breakthrough in this embodiment, requiring the simultaneous achievement of sample positioning and oil storage functions within a limited space.

[0039] In this embodiment, the horizontal displacement of the sample is precisely constrained by the groove 120. A fixed amount of lubricating oil is injected into the four corner fan-shaped oil reservoirs before the test. Under high-temperature conditions, the oil expands due to heat and diffuses along the edge of the groove 120 to the friction contact surface. An annular gap oil reservoir is formed between the inner wall of the through-hole, the upper surface of the sample, and the friction probe, ensuring that the friction contact surface maintains appropriate lubrication at all times. This achieves stable clamping of the sample during high-temperature friction testing, while the built-in oil reservoir structure maintains a continuous supply of lubricating oil. The integrated design of the sample fixing area and the oil reservoir avoids the need for frequent interruptions to replenish oil required by traditional fixtures, improving testing efficiency and data continuity.

[0040] like Figure 1 In some embodiments, the base 100 is provided with a first mounting hole 140, which is distributed in a circumferential array around the center of the bottom surface of the step 110 and located outside the groove 120. The cover 200 is provided with a second mounting hole aligned with the first mounting hole 140, which is located outside the through hole 220. The first mounting hole 140 and the second mounting hole are used to fix the cover 200 to the base 100 by bolt assembly.

[0041] In this embodiment, the first assembly hole 140 refers to a hole structure distributed on the bottom surface of the base step and located outside the groove 120. Specifically, it can be achieved by drilling and evenly distributing the holes along the outer edge of the groove 120, corresponding to the second assembly hole on the cover 200. The second assembly hole refers to a hole structure on the cover 200 corresponding to the position of the first assembly hole 140, used for bolt through-fixation. Bolt assembly refers to connecting the base 100 and the cover 200 using threaded fasteners. Specifically, it can be achieved using standard bolts with nuts or threaded holes, forming a stable mechanical fixation. In some preferred embodiments, there are three of each of the first and second assembly holes, and the straight-line distance between the centers of the first assembly holes 140 is 25mm. A straight-line distance of 25mm between the centers effectively matches the standard interface of the friction testing machine base, ensuring assembly compatibility. If the spacing is too large, installation will be impossible; if it is too small, the expansion allowance will be limited, causing bolt deformation.

[0042] In this embodiment, during assembly, bolts are sequentially passed through the second mounting hole of the cover 200 and the first mounting hole 140 of the base. By tightening the bolts on the base of the friction testing machine, the cover 200 and the base 100 are pressed and fixed together. Because the mounting holes are arranged in a circumferential array, the force on the cover 200 and the base 100 is more even, avoiding localized stress concentration that could lead to fixture deformation. This ensures that the contact surfaces of the sample and the friction probe remain aligned throughout the friction test, improving the stability and repeatability of friction coefficient measurement under high-temperature conditions.

[0043] In some embodiments, the bolt passes through the second mounting hole from the top of the cover 200 and exits through the first mounting hole 140 of the base 100. The protruding end of the bolt locks with the positioning hole of the friction testing machine base, thereby fixing the high-temperature friction fixture to the friction testing machine. The bolt is a fastener used to connect the cover 200 and the base 100, specifically a threaded metal rod with an extension extending beyond the lower surface of the base 100 at its end. The positioning hole is a pre-set fixing hole on the friction testing machine base, specifically a slotted structure matching the shape of the bolt end, used to limit the displacement of the fixture during the test.

[0044] When the cover 200 and the base 100 are assembled with bolts, the bolts pass through the second assembly hole of the cover 200 from top to bottom and enter the first assembly hole 140 of the base 100. Finally, the extended end of the bolt is embedded in the positioning hole of the friction testing machine base. During this process, the fit between the bolt end and the positioning hole forms a rigid constraint, preventing relative displacement between the fixture and the testing machine base. Therefore, the stability of the fixture is ensured during friction testing in high-temperature environments, avoiding sample position shift due to vibration or thermal expansion. This solves the problem of sample position shift caused by fixture loosening during high-temperature friction testing, ensuring that the contact surface of the sample remains stably aligned with the friction probe throughout the test, thereby improving the accuracy of the friction coefficient measurement results.

[0045] In some embodiments, the fan-shaped oil reservoir 130 is in the shape of a 3 / 4 circle, with the center of the 3 / 4 circle coinciding with the vertex of the square shape of the groove 120. The 3 / 4 circle shape refers to the fan-shaped structure with a central angle of 270 degrees in the cross-sectional profile of the oil reservoir. This shape design can create a large oil storage space and form uniform lubricant diffusion channels at the four corners of the sample fixing area. The center coinciding with the vertex of the square means that the center point of the arc of the oil reservoir is aligned with the right-angle endpoint of the square sample fixing area, allowing the lubricant to be evenly distributed along the diagonal direction of the square sample.

[0046] The 3 / 4 circle design in this embodiment increases oil storage capacity while maintaining structural strength, effectively solving the problem of insufficient lubrication at the corners of square samples. During high-temperature friction testing, it can maintain a continuous and uniform distribution of lubricant at the sample edges, avoiding deviations in friction coefficient measurement caused by local lubrication failure, and improving the accuracy and repeatability of experimental data.

[0047] like Figure 2 and Figure 4 As shown, in some embodiments, the groove 120 is provided with a groove liner 150, the outer wall of the groove liner 150 is fitted to the inner wall of the groove 120, a square through area 151 is provided at the center of the groove liner 150, and a third oil storage cavity 152 is provided at the four corners of the square through area 151. The groove liner 150 refers to a replaceable auxiliary structure covering the inner wall of the groove 120, whose outer wall fits tightly with the inner wall of the groove 120, used to adapt to samples of different sizes and enhance sealing. The square through area 151 is used for testing smaller sample sizes. The third oil storage cavity 152 refers to the oil storage space provided at the four corners of the square through area 151, which is similar to the fan-shaped oil storage cavity. Traditional fixtures do not have a replaceable groove liner structure and cannot adapt to samples of different sizes. This embodiment solves the sample adaptability problem by adding a groove liner 150 with an oil storage cavity.

[0048] In some embodiments, the bottom surface of the groove 120 is provided with a magnetic element for magnetically attracting and fixing the groove liner 150 to the groove 120. The magnetic element refers to a component capable of generating a magnetic field, specifically a permanent magnet or electromagnet, which magnetically attracts the groove liner 150, ensuring the liner remains fixed within the groove 120. The groove liner 150 is a replaceable component placed within the groove, specifically made of soft magnetic material or a metal material with a magnetic coating. Its function is to enable quick installation and removal through attraction with the magnetic element, while providing a stable support surface for the sample. This embodiment achieves stable fixing and convenient replacement of the groove liner, solving the problem of liner displacement or loosening under high-temperature conditions, thereby ensuring the stability of lubricant supply and improving the reliability and repeatability of friction test data.

[0049] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A high-temperature friction fixture for friction testing, characterized in that, include: The base (100) has a step (110) on top. A groove (120) is provided at the center of the bottom surface of the step (110). The groove (120) is a square sample fixing area for placing samples. Fan-shaped oil storage cavities (130) are provided at the four corners of the groove (120). The fan-shaped oil storage cavities (130) are connected to the sample fixing area. The fan-shaped oil storage cavities (130) are fan-shaped with a central angle greater than 180°. The depth of the fan-shaped oil storage cavities (130) is the same as the groove depth of the groove (120). The cover (200) has a boss (210) at the bottom and a through hole (220) at the center of the boss (210). The through hole (220) is used for the friction probe of the friction testing machine to sink freely. There is an assembly gap between the top surface of the boss (210) and the bottom surface of the step (110). The inner wall of the through hole (220) forms an annular gap oil storage cavity between the upper surface of the sample and the friction probe.

2. The high-temperature friction fixture for friction testing according to claim 1, characterized in that: The base (100) is provided with a first mounting hole (140), which is arranged in a circular array around the center of the bottom surface of the step (110) and located outside the groove (120). The cover (200) is provided with a second mounting hole aligned with the first mounting hole (140), which is located outside the through hole (220). The first mounting hole (140) and the second mounting hole are used to fix the cover (200) on the base (100) by bolt assembly.

3. A high-temperature friction fixture for friction testing according to claim 2, characterized in that: The bolt passes through the second mounting hole from the top of the cover (200) and through the first mounting hole (140) of the base (100). The protruding part of the end of the bolt is locked with the positioning hole of the friction testing machine base, so that the high temperature friction fixture is fixedly assembled on the friction testing machine.

4. A high-temperature friction fixture for friction testing according to claim 1, characterized in that: The fan-shaped oil storage cavity (130) is in the shape of a 3 / 4 circle, and the center of the 3 / 4 circle coincides with the vertex of the square shape of the groove (120).

5. A high-temperature friction fixture for friction testing according to claim 1, characterized in that, The groove (120) is provided with a groove liner (150), the outer side wall of the groove liner (150) is in contact with the inner side wall of the groove (120), a square through area (151) is provided at the center of the groove liner (150), and a third oil storage cavity (152) is provided at the four corners of the square through area (151).

6. A high-temperature friction fixture for friction testing according to claim 5, characterized in that, The bottom surface of the groove (120) is provided with a magnetic element for magnetically attracting the groove liner (150) to be fixed on the groove (120).

7. A high-temperature friction fixture for friction testing according to claim 1, characterized in that, The groove (120) has a side length of 20mm and a groove depth of 1.2mm.

8. A high-temperature friction fixture for friction testing according to claim 1, characterized in that, The sector-shaped oil storage cavity (130) has a sector radius of 1 mm and a depth of 1.2 mm.

9. A high-temperature friction fixture for friction testing according to claim 1, characterized in that, The diameter of the through hole (220) is 24.4 mm, and the gap between the inner wall of the through hole (220) and the friction probe is 0.2 mm.

10. A high-temperature friction fixture for friction testing according to claim 2, characterized in that, The first assembly hole (140) and the second assembly hole are each provided in three parts, and the straight-line distance between the centers of the first assembly holes (140) is 25mm.

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