PTFE oil seal lip piece pre-tightening load testing device and testing method thereof

Abstract

The invention relates to a PTFE oil seal lip piece pre-tightening load testing device and a testing method thereof.The PTFE oil seal lip piece pre-tightening load testing device comprises a tension testing machine, a first clamping device and a second clamping device, the first clamping device and the second clamping device are arranged on the tension testing machine, a fixing piece is arranged on the first clamping device, a lip piece is connected with the first clamping device through the fixing piece, and the second clamping device is connected with the second clamping device through the fixing piece. An abutting piece is arranged on the second clamp holder, an outer diameter check block is arranged on the lip piece, and one side of the abutting piece abuts against one side face of the outer diameter check block; during installation, the lip piece is installed on the first clamping device through the fixing piece, then the abutting piece is connected with the outer diameter check block in a sleeving and abutting mode, the abutting piece is installed on the second clamping device, then the first clamping device and the second clamping device are installed on the tension testing machine, the tension testing machine is started at the moment to conduct tension testing, and a testing result is obtained after testing is completed. The method has the effect of conveniently and quickly judging whether the product quality is qualified or not.

Description

Technical Field

[0001] The present application relates to the field of lip testing equipment, and in particular to a PTFE oil seal lip preload testing device and a testing method thereof. Background Art

[0002] PTFE oil seal lip refers to the core part of the oil seal, which is made of polytetrafluoroethylene material and directly contacts the surface of the rotating shaft to form a dynamic seal. It has extremely low friction and wear, as well as excellent chemical resistance.

[0003] Since the sealing force of PTFE oil seals is entirely derived from the combination of their material properties and precise geometric design, preload testing is required to ensure their basic sealing function, verify design consistency and manufacturing process stability, and predict dynamic sealing performance.

[0004] In the related art, reference can be made to the utility model patent with announcement number CN211681732U, which discloses a device for measuring the clamping force of PTFE lips, including an upper mold plate and a lower mold plate that are stacked and detachably connected. The middle parts of the upper mold plate and the lower mold plate are penetrated by through holes, and a boss is provided circumferentially on the lower surface of the upper mold plate, and a groove matching the boss is provided on the upper surface of the lower mold plate, and the groove is connected to the through hole of the lower mold plate; only the PTFE lip needs to be used for measurement, and after the test results are adjusted to the appropriate range, the PTFE lip is pressed into a finished product to reduce material consumption.

[0005] In the above-mentioned related technologies, radial pressure is measured during the clamping force test. There are many interference factors during the measurement, and the measurement data needs to be processed before the test results can be obtained. In addition, the installation process is cumbersome, which is not conducive to rapid detection and judgment of product quality. Summary of the Invention

[0006] In order to solve the problem that data needs to be processed during the clamping force test and the installation process is cumbersome, which is not conducive to rapid detection and judgment of product quality, the present application provides a PTFE oil seal lip preload test device and a test method thereof.

[0007] The present application provides a PTFE oil seal lip preload test device and test method using the following technical solutions: A PTFE oil seal lip preload testing device includes a tensile testing machine, a first clamp and a second clamp, the first clamp and the second clamp are arranged on the tensile testing machine and are relatively distributed, the tensile testing machine is used to pull the first clamp and the second clamp to move in opposite directions, a fixing piece is provided on the first clamp, and the lip is connected to the first clamp via the fixing piece, the second clamp is provided with an abutment piece, and an outer diameter stop is provided on the circumferential outer wall of the lip, and one side of the abutment piece abuts against a side of the outer diameter stop facing the first clamp.

[0008] By adopting the above technical solution, during installation, the lip piece is first installed on one side of the first clamp through the fixing part, and then the abutment piece is sleeved and abutted on one side of the outer diameter stop block of the lip piece. At this time, the abutment piece is installed on the second clamp, and then the first clamp and the second clamp are respectively installed on the tensile testing machine. At this time, the tensile testing machine is started to perform tensile testing on the first clamp and the second clamp, and the data is obtained for comparison. The test result is known when the test is completed, which is convenient for quickly judging whether the product quality is qualified.

[0009] Optionally, the fixing member includes a fixing plate, the first clamp includes a first connecting rod and a first connecting plate coaxially arranged at one end of the first connecting rod, a connecting screw is coaxially arranged on one side of the first connecting plate, the fixing plate is coaxially arranged on one side of the first connecting plate, a threaded hole is provided on the fixing plate, the connecting screw is threadedly connected to the fixing plate through the threaded hole, a fixing ring is provided at the outer peripheral wall of the fixing plate, a limiting ring is provided on a side surface of the first connecting plate, and an accommodating groove is formed between the limiting ring and the fixing ring. During installation, one side of the lip piece is embedded in the limiting ring and the fixing ring through the accommodating groove, and the outer diameter stop block is connected to the side of the lip piece facing away from the fixing ring.

[0010] By adopting the above technical solution, the accommodating groove formed by the limiting ring and the fixing ring can firmly embed the lip piece, ensure the stability of the lip piece installation, and thus ensure that the position of the lip piece is fixed during the test, thereby improving the accuracy of the test results. The fixing plate and the first connecting plate are threadedly connected by the connecting screw and the threaded hole, which facilitates the installation and disassembly of the fixing plate.

[0011] Optionally, the outer diameter stop block includes a coaxially distributed exoskeleton and an inner skeleton, the exoskeleton is arranged at the outer peripheral wall of the lip, the exoskeleton is provided with a first fold edge and a second fold edge coaxially distributed up and down, a rubber ring is provided on one side of the lip, the rubber ring is fitted with one side of the second fold edge, the inner skeleton is arranged on the side of the lip away from the second fold edge and abuts against a side of the first fold edge of the exoskeleton, and the abutment is abutted against a side of the first fold edge.

[0012] By adopting the above technical solution, during installation, the rubber ring, lip and inner frame are assembled in sequence, the outer frame is set at the outer peripheral wall of the lip, the inner frame abuts against the first folded edge of the outer frame, the rubber ring fits against the second folded edge of the outer frame, and the abutment abuts against the first folded edge to form a seal, so that the lip is stably installed, which is convenient for accurately testing the preload of the PTFE oil seal lip and convenient for judging whether the product quality is qualified.

[0013] Optionally, the abutment includes an abutment ring and an extended retaining ring, the second clamp includes a second connecting rod and a second connecting disk coaxially arranged at one end of the second connecting rod, a sleeve is coaxially arranged on one side of the second connecting disk, the abutment ring is sleeved on the inner side of the sleeve, the abutment ring and the sleeve are detachably connected through a connecting member, the extended retaining ring is coaxially arranged on the side of the abutment ring away from the second connecting disk, and the extended retaining ring abuts against the side of the first folded edge away from the lip.

[0014] By adopting the above technical solution, the extended retaining ring abuts against the side of the first folded edge away from the lip piece, and the abutting ring and the sleeve ring are detachably connected, which facilitates the installation and disassembly of the abutting part. After installation, the force is accurately applied to the lip piece outer diameter stop block, and the lip piece preload test is completed in conjunction with the tensile testing machine.

[0015] Optionally, the connecting member includes a pin, a first through hole is provided on the collar, and a second through hole is provided on the abutting ring. The pin inserts and fixes the collar and the abutting ring through the first through hole and the second through hole. A sliding bar is provided on the outer peripheral wall of the abutting ring, and a sliding groove is provided on the inner peripheral wall of the collar. The sliding bar is slidably connected to the collar through the sliding groove, and a limiting member for pre-positioning the abutting ring is provided on the collar.

[0016] By adopting the above technical solution, the sliding strip on the outer peripheral wall of the abutment ring cooperates with the sliding groove on the inner peripheral wall of the sleeve for guidance, and the limit piece on the sleeve can pre-position the abutment ring, which is convenient for the installation and positioning of the abutment ring and the sleeve. The pin connects the sleeve and the abutment ring through the first through hole and the second through hole to achieve fixation of the two, thereby improving the convenience and accuracy of the assembly of the test device.

[0017] Optionally, the limit member includes a moving block and a guide rod, the moving block is slidably installed on the ring along the radial direction of the ring, a guide rod slidably connected to the ring is provided on one side of the moving block, a spring is provided on the guide rod, one end of the guide rod is located outside the ring, a limiting block is provided on the side of the ring facing away from the guide rod, an embedding groove is provided on the outer peripheral wall of the abutment ring, and the limit block is plug-connected to the abutment ring through the embedding groove.

[0018] By adopting the above technical solution, during installation, the abutment ring pushes the limit block and then pushes the moving block to move, the spring on the guide rod is compressed, and when the abutment ring moves to the position where the groove is located at the limit block, the spring pushes the limit block to connect with the abutment ring through the groove, thereby realizing pre-positioning of the abutment ring and facilitating the subsequent pin positioning between the abutment ring and the sleeve ring.

[0019] Optionally, the tensile testing machine is provided with identical first and second clamps relative to each other, the first clamp and the second clamp are slidably installed on the tensile testing machine in opposite directions, the first connecting rod is detachably connected to the first clamp, and the second connecting rod is detachably connected to the second clamp.

[0020] By adopting the above technical solution, the first connecting rod and the first clamp, and the second connecting rod and the second clamp are detachably connected, which facilitates the installation and disassembly of the first clamp and the second clamp, facilitates the assembly and maintenance of the test device, and adapts to different test requirements.

[0021] Optionally, the first clamp includes a mounting block, a first clamping block and a second clamping block, the mounting block is arranged at the driving end of the hydraulic system of the tensile testing machine, the first clamping block and the second clamping block are slidably installed on the mounting block in opposite directions, the first clamping block and the second clamping block clamp one end of the first connecting rod, the mounting block is provided with a rotating screw, the rotating screw is provided with two opposite sections of threads, the first clamping block and the second clamping block are respectively threadedly connected to the rotating screw at the two sections of threads.

[0022] By adopting the above technical solution, the two opposite threads on the screw are rotated to move the first clamping block and the second clamping block toward or away from each other, thereby achieving the clamping or loosening of one end of the first connecting rod, facilitating the detachable connection between the first connecting rod and the first clamp, and facilitating the assembly and disassembly of the test device.

[0023] Optionally, arc grooves are provided on the first clamping block and the second clamping block, and the arc grooves on both sides are relatively distributed and form a cylindrical shape. When the first connecting rod is clamped, the outer peripheral wall of the first connecting rod abuts against one side wall of the arc groove of the first clamping block and the second clamping block. Positioning holes are provided on the first clamping block and the second clamping block, and two relatively distributed positioning columns are provided on the first connecting rod, and the positioning columns are plugged into and connected to the first clamping block and the second clamping block through the positioning holes.

[0024] By adopting the above technical solution, during installation, the first clamping block and the second clamping block are driven to move to the arc groove to fit the outer wall of the first connecting rod, thereby achieving effective clamping of the first connecting rod. At the same time, the positioning column on the first connecting rod is plugged into the positioning holes on the first clamping block and the second clamping block to position and fix the first connecting rod, thereby ensuring the stability of the position of the first connecting rod during the tensile test.

[0025] A PTFE oil seal lip preload test method, characterized by comprising the following test steps: S1, cut off the lip and accessory lip; S2. Assemble the rubber pad, lip, and inner frame onto the second folded edge of the outer frame in sequence, and roll the first folded edge of the outer frame to press the inner frame and lip tightly to form a seal; S3. Place the assembled seal on the retaining ring, thread the retaining ring onto the first holder, and calculate the compression amount of the retaining lip according to the formula; Where, △t is the compression amount (30% to 35%), %; h2 is the height of the lower fixture, in millimeters (mm); h1 is the height of the upper fixture, in millimeters (mm); t is the thickness of the lip, in millimeters (mm); S4. Sleeve the abutment ring until it abuts against the outer diameter stopper on the seal, then move the second holder to the abutment ring, and connect the abutment ring to the second holder with a pin; S5, connecting the second clamp to the second fixture, and connecting the first clamp to the first fixture; S6. Start the tensile testing machine and pull the fixture at a certain speed for testing until the sealing lip is detached or broken.

[0026] By adopting the above technical solution, the lip is made into a seal and then fixed. The detachable abutment ring is used to abut one side of the seal. Then, the first clamp and the second clamp are pulled in opposite directions to test the preload force of the lip, and the test effect is good.

[0027] In summary, this application includes at least one of the following beneficial technical effects: 1. Able to perform preload test on PTFE oil seal lip to ensure its basic sealing function, verify design consistency and manufacturing process stability, and predict dynamic sealing performance; 2. There are few interference factors during the test, and the test results can be obtained without processing the measurement data; 3. The installation process is simple, making it easy to quickly determine whether the product quality is qualified. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of this application.

[0029] Figure 2 It is a cross-sectional view of the first clamper and the second clamper of the present application along the axis direction of the first connecting rod.

[0030] Figure 3 It is an enlarged cross-sectional view of part A of this application.

[0031] Figure 4 It is a schematic diagram of the explosion structure between the abutment member and the second clamper of the present application.

[0032] Figure 5 It is an enlarged cross-sectional view of part B of this application.

[0033] Figure 6 It is a schematic diagram of a partial cross-sectional structure of the first clamp of the present application.

[0034] Those skilled in the art will appreciate that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size and position of some elements in the drawings may be exaggerated relative to other elements to help improve understanding of the embodiments of the present invention.

[0035] Reference numerals: 1, tensile testing machine; 2, first clamp; 21, first connecting rod; 211, positioning column; 22, first connecting plate; 221, limiting ring; 23, connecting screw; 3, second clamp; 31, second connecting rod; 32, second connecting plate; 33, collar; 331, first through hole; 332, sliding groove; 34, pin; 4, fixing plate; 41, threaded hole; 42, fixing ring; 5, lip; 51, outer diameter stopper; 511, outer frame; 5111, first folding Edge; 5112, second folding edge; 512, inner skeleton; 52, rubber ring; 6, abutment; 61, abutment ring; 611, second through hole; 612, sliding bar; 62, extension retaining ring; 63, embedded groove; 7, limiter; 71, moving block; 72, guide rod; 73, spring; 74, limiter; 8, first clamp; 81, mounting block; 82, first clamping block; 821, arc groove; 822, positioning hole; 83, second clamping block; 84, rotating screw; 9, second clamp. DETAILED DESCRIPTION

[0036] The present application is further described in detail below with reference to the accompanying drawings.

[0037] The present application embodiment is a PTFE oil seal lip preload test device, referring to Figure 1 and Figure 2, including a tensile testing machine 1, a first clamp 2 and a second clamp 3. The first clamp 2 and the second clamp 3 are arranged on the tensile testing machine 1 and are relatively distributed in the vertical direction. The tensile testing machine 1 is used to pull the first clamp 2 and the second clamp 3 to move in opposite directions along the vertical direction. A fixing part is provided on the first clamp 2, and the lip 5 is connected to the first clamp 2 through the fixing part. The second clamp 3 is provided with an abutment 6, and an outer diameter stop 51 is provided on the circumferential outer wall of the lip 5. One side of the abutment 6 abuts against the side of the outer diameter stop 51 facing the first clamp 2. During installation, first install the lip piece 5 on one side of the first clamp 2 through the fixing part, then sleeve the abutment 6 on the side of the outer diameter stopper 51 of the lip piece 5, and at the same time install the abutment 6 on the second clamp 3, and then install the first clamp 2 and the second clamp 3 on the tensile testing machine 1 respectively. At this time, start the tensile testing machine 1, so that the first clamp 2 and the second clamp 3 can produce relative movement under the action of the tensile testing machine 1, and perform a tensile test on the first clamp 2 and the second clamp 3. The data is compared and the test results are known when the test is completed, so that it is quickly judged whether the product quality is qualified.

[0038] Reference Figure 1 and Figure 2 The first clamper 2 includes a first connecting rod 21 and a first connecting disk 22 coaxially arranged at one end of the first connecting rod 21. A connecting screw 23 is coaxially arranged on the side of the first connecting disk 22 away from the first connecting rod 21. The fixing part includes a fixing disk 4. The fixing disk 4 is generally disc-shaped. The fixing disk 4 is coaxially arranged on one side of the connecting screw 23 of the first connecting disk 22. A penetrating threaded hole 41 is provided on the fixing disk 4. The connecting screw 23 is threadedly connected to the fixing disk 4 through the threaded hole 41.

[0039] Reference Figure 2 and Figure 3 A fixing ring 42 is coaxially disposed on the outer peripheral wall of the fixing disk 4, on the side facing away from the first connecting disk 22. A coaxially disposed limiting ring 221 is disposed on the side of the first connecting disk 22 facing the fixing disk 4. The radius of the limiting ring 221 is greater than that of the fixing ring 42, and an L-shaped receiving groove is formed between the limiting ring 221 and the fixing ring 42. The lip 5 is annular and coaxially disposed with the fixing disk 4. The cross-section of the lip 5 is L-shaped and comprises a horizontal ring and a vertical ring. The horizontal ring is coaxially disposed on the outer peripheral wall of the vertical ring. One side of the vertical ring of the lip 5 is embedded in the limiting ring 221 and the fixing ring 42 through the receiving groove. One side of the horizontal ring of the lip 5 is located outside the fixing disk 4, and an outer diameter stopper 51 is connected to one side of the horizontal ring of the lip 5. The vertical section of the lip 5 is embedded in the accommodating groove formed by the limiting ring 221 and the fixing ring 42. The fixing plate 4 and the first connecting plate 22 are threadedly connected through the connecting screw 23 and the threaded hole 41 to clamp the lip 5. The position of the lip 5 is fixed during the test.

[0040] Reference Figure 2 and Figure 3 The outer diameter stopper 51 includes a coaxially distributed outer skeleton 511 and an inner skeleton 512. The inner skeleton 512 is arranged at the inner peripheral wall of the outer skeleton 511. The outer skeleton 511 is coaxially arranged at the outer peripheral wall of the lip 5. The outer skeleton 511 is provided with a first folded edge 5111 and a second folded edge 5112 coaxially distributed up and down. The downward side of the horizontal section of the lip 5 is provided with a coaxially distributed rubber ring 52. The downward side of the rubber ring 52 is in contact with the upward side of the second folded edge 5112, the downward side of the inner skeleton 512 is in contact with the upward side of the lip 5, and the upward side of the inner skeleton 512 is in contact with the downward side of the first folded edge 5111. The outer diameter stopper 51 and the lip 5 form a seal after assembly, which is convenient for installation and testing and can effectively achieve the test effect of the preload force of the lip 5.

[0041] Reference Figure 2 and Figure 4 The abutment member 6 includes an abutment ring 61 and an extended retaining ring 62. The second clamper 3 includes a second connecting rod 31 and a second connecting disk 32 coaxially arranged at one end of the second connecting rod 31. A collar 33 is coaxially arranged on the side of the second connecting disk 32 facing away from the second connecting rod 31. The abutment ring 61 is sleeved on the inner circumferential wall of the collar 33. The abutment ring 61 and the collar 33 are detachably connected via a connecting member. The extended retaining ring 62 is coaxially arranged on the side of the abutment ring 61 facing away from the collar 33. The inner circumferential wall of the extended retaining ring 62 is in contact with the outer circumferential wall of the first connecting disk 22, and the downward side of the extended retaining ring 62 abuts the upward side of the first folded edge 5111. During testing, the abutment ring 61 is pulled by the collar 33 to push the first folded edge 5111 side of the seal to perform a preload test.

[0042] Reference Figure 2 and Figure 4 The connecting member includes a pin 34. The collar 33 is provided with a first through-hole 331 extending through the circumference of the collar 33. The abutting ring 61 is provided with a second through-hole 611 extending through the circumference of the abutting ring 61. The pin 34 inserts and secures the collar 33 and the abutting ring 61 through the first and second through-holes 331 and 611. A sliding bar 612 is provided on the outer circumferential wall of the abutting ring 61. The sliding bars 612 are arranged parallel to the axis of the abutting ring 61. There are four sliding bars 612, which are evenly spaced along the circumference of the abutting ring 61. The inner circumferential wall of the collar 33 is provided with a sliding groove 332, which corresponds to the position of the sliding groove 332. The sliding bar 612 is slidably connected to the collar 33 through the sliding groove 332, guiding the sliding bars 612 on the outer circumferential wall of the abutting ring 61 and the sliding groove 332 on the inner circumferential wall of the collar 33.

[0043] Reference Figure 4 and Figure 5The collar 33 is provided with a limit member 7 for pre-positioning the abutment ring 61. The limit member 7 includes a moving block 71 and a guide rod 72. The moving block 71 is slidably installed on the collar 33 along the radial direction of the collar 33. A guide rod 72 is provided on one side of the moving block 71 and is slidably connected to the collar 33. One end of the guide rod 72 is located outside the collar 33. A spring 73 is sleeved on the guide rod 72. A limit block 74 is provided on the side of the collar 33 away from the guide rod 72. An embedding groove 63 is provided on the outer peripheral wall of the abutment ring 61. The limit block 74 is plugged into the abutment ring 61 through the embedding groove 63. The side of the limit block 74 away from the guide rod 72 is provided with an inclined section. When the abutment ring 61 pushes the limit block 74 and then pushes the moving block 71 to move, the spring 73 on the guide rod 72 is compressed. When the abutment ring 61 moves to the position where the embedding groove 63 is located at the limit block 74, the spring 73 pushes the limit block 74 to be plugged into the abutment ring 61 through the embedding groove 63, thereby realizing the pre-positioning of the abutment ring 61, facilitating the subsequent positioning of the pin 34 between the abutment ring 61 and the ring 33.

[0044] Reference Figure 1 and Figure 6 The tensile testing machine 1 is provided with a first clamp 8 and a second clamp 9 that are completely identical and relatively distributed. The first clamp 8 and the second clamp 9 are slidably installed on the tensile testing machine 1 in opposite directions. The first connecting rod 21 is detachably connected to the first clamp 8, and the second connecting rod 31 is detachably connected to the second clamp 9.

[0045] Reference Figure 6 The first clamp 8 includes a mounting block 81, a first clamping block 82 and a second clamping block 83. The mounting block 81 is arranged at the driving end of the hydraulic system of the tensile testing machine 1. The first clamping block 82 and the second clamping block 83 are horizontally slidably installed on the downward side of the mounting block 81. The first clamping block 82 and the second clamping block 83 slide in opposite directions. A rotating screw 84 is rotatably installed on the mounting block 81. The rotating screw 84 is distributed along the length direction of the mounting block 81. Two opposite threads are provided on the rotating screw 84. The first clamping block 82 and the second clamping block 83 are respectively threadedly connected to the rotating screw 84 at the two threads.

[0046] Reference Figure 6The mounting block 81 is used to connect the hydraulic system of the tensile testing machine 1. The first clamping block 82 and the second clamping block 83 are provided with arc grooves 821. The arc grooves 821 on both sides are relatively distributed and form a cylindrical shape. When the first connecting rod 21 is clamped, the outer peripheral wall of the first connecting rod 21 abuts against the side wall of the arc groove 821 of the first clamping block 82 and the second clamping block 83. The first clamping block 82 and the second clamping block 83 are provided with a through positioning hole 822. Two relatively distributed positioning columns 211 are provided on the outer peripheral wall of the first connecting rod 21. The same positioning column 211 is provided on the second connecting rod 31. The positioning column 211 is plugged and connected to the first clamping block 82 and the second clamping block 83 through the positioning hole 822. The shape of the arc groove 821 is compatible with the outer wall of the first connecting rod 21, which can effectively clamp the first connecting rod 21. The plug-in connection between the positioning column 211 and the positioning hole 822 ensures the stability of the position of the first connecting rod 21 during the tensile test.

[0047] The working principle of this embodiment is as follows: First, the lip piece 5 is made into a seal. The inner frame 512, the lip piece 5, and the sealing ring are sequentially assembled to the outer frame 511 and the first folded edge 5111 is rolled to form a seal. The lip piece 5 is then placed on the fixing plate 4 and screwed together with the fixing plate 4 and the connecting screw 23 so that one side of the lip piece 5 is embedded in the receiving groove formed by the abutting ring 61 and the fixing ring 42 to ensure that the lip piece 5 is firmly installed. Then, the abutment ring 61 is sleeved on one side of the outer diameter stopper 51 of the lip piece 5, and the collar 33 is slidably sleeved on the abutment ring 61. During the movement of the abutment ring 61, the limit block 74 and the moving block 71 are pushed to compress the spring 73 on the guide rod 72. When the abutment ring 61 moves to the embedded groove 63 and is located at the limit block 74, the spring 73 pushes the limit block 74 through the embedded groove 63 to be plugged and connected with the abutment ring 61 to achieve pre-positioning, and then the pin 34 passes through the collar 33 and the abutment ring The through-hole on 61 securely connects the two. Next, the first clamp 2 and second clamp 3, with the lip 5 and abutment 6 installed, are respectively installed on the first clamp 8 and second clamp 9 of the tensile testing machine 1. The rotating screw 84 is rotated to move the first clamping block 82 and the second clamping block 83 toward each other, clamping the outer peripheral wall of the first connecting rod 21. Simultaneously, the positioning post 211 is inserted into the positioning hole 822 to achieve positioning. The second connecting rod 31 is similarly detachably connected to the second clamp 9. Finally, the tensile testing machine 1 is activated, pulling the first clamp 2 and the second clamp 3 in opposite directions to perform a tensile test on the lip 5, obtain the preload data of the lip 5, and determine whether the product is qualified.

[0048] The present invention provides a method for testing the preload of a PTFE oil seal lip, comprising the following steps: S1. Cut off the auxiliary lip of the lip piece 5. During the operation, fix the lip piece 5 on a suitable fixture to ensure that the position of the lip piece 5 is stable during the cutting process.

[0049] S2. Assemble the rubber pad, the lip 5 processed in S1 and the inner frame 512 onto the second folded edge 5112 of the outer frame 511 in sequence, and roll the first folded edge 5111 of the outer frame 511 to press the inner frame 512 and the lip 5 to form a seal.

[0050] S3. Place the assembled seal on the fixing ring 42, and screw the fixing ring 42 onto the first holder 2. The compression amount of the fixing lip 5 is calculated according to the formula; Wherein, △t is the compression amount (30% to 35%), %; h2 is the height of the lower fixture, in millimeters (mm); h1 is the height of the upper fixture, in millimeters (mm); t is the thickness of the lip 5, in millimeters (mm).

[0051] S4. Slide the abutment ring 61 until it abuts the outer diameter stopper 51 on the seal, then move the second holder 3 to the abutment ring 61 and connect the abutment ring 61 to the second holder 3 via the pin 34. When inserting the abutment ring 61, slide it along the sliding groove 332 of the collar 33 until it abuts the outer diameter stopper 51, and then insert the pin 34 to secure it.

[0052] S5. Connect the second clamper 3 to the second fixture 9, and connect the first clamper 2 to the first fixture 8.

[0053] S6. Start the tensile testing machine 1 and pull the fixture at a constant speed until the sealing lip 5 detaches or breaks. During the test, closely observe the readings of the tensile testing machine 1 and the state of the lip 5. When the sealing lip 5 detaches or breaks, record the tensile force data at that moment.

[0054] The implementation principle of this embodiment is: during installation, the auxiliary lip of the lip piece 5 is first cut off and cleaned, and then the yellow rubber pad, the lip piece 5 and the inner frame 512 are assembled on the outer frame 511, and the first folded edge 5111 is rolled to form a seal, and then the seal is threadedly installed on the first clamp 2 through the fixing ring 42, and then the abutment ring 61 is sleeved and set on one side of the exterior block. At this time, the second clamp 3 is slid and the abutment ring 61 is connected through the pin 34, and then the first clamp 2 is fixed to the first clamp 8, and the second clamp 3 is fixed to the second clamp 9, and then the tensile testing machine 1 is started for testing. This testing method makes the lip piece 5 into a seal and installs and fixes it through a series of orderly steps, and uses the tensile testing machine 1 to perform a preload test.

[0055] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A PTFE oil seal lip preload test device, comprising a tensile testing machine (1), a first clamp (2) and a second clamp (3), characterized in that: The first clamp (2) and the second clamp (3) are arranged on the tensile testing machine (1) and are relatively distributed. The tensile testing machine (1) is used to pull the first clamp (2) and the second clamp (3) to move in opposite directions. A fixing piece is provided on the first clamp (2), and the lip (5) is connected to the first clamp (2) through the fixing piece. An abutment piece (6) is provided on the second clamp (3). An outer diameter stopper (51) is provided on the circumferential outer wall of the lip (5), and one side of the abutment piece (6) abuts against a side of the outer diameter stopper (51) facing the first clamp (2).

2. A PTFE oil seal lip preload test device according to claim 1, characterized in that: The fixing member includes a fixing plate (4), the first clamper (2) includes a first connecting rod (21) and a first connecting plate (22) coaxially arranged at one end of the first connecting rod (21), a connecting screw (23) coaxially arranged on one side of the first connecting plate (22), the fixing plate (4) is coaxially arranged on one side of the first connecting plate (22), a threaded hole (41) is provided on the fixing plate (4), and the connecting screw (23) is connected to the fixing plate (4) through the threaded hole (41). 4) threaded connection, a fixing ring (42) is provided on the outer peripheral wall of the fixing disk (4), a limiting ring (221) is provided on one side of the first connecting disk (22), and an accommodating groove is formed between the limiting ring (221) and the fixing ring (42). During installation, one side of the lip (5) is embedded in the limiting ring (221) and the fixing ring (42) through the accommodating groove, and the outer diameter stopper (51) is connected to the side of the lip (5) facing away from the fixing ring (42).

3. A PTFE oil seal lip preload test device according to claim 2, characterized in that: The outer diameter stopper (51) includes a coaxially distributed outer frame (511) and an inner frame (512), the outer frame (511) is arranged at the outer peripheral wall of the lip (5), the outer frame (511) is provided with a first folding edge (5111) and a second folding edge (5112) coaxially distributed up and down, a rubber ring (52) is provided on one side of the lip (5), the rubber ring (52) is in contact with one side of the second folding edge (5112), the inner frame (512) is arranged at a side of the lip (5) away from the second folding edge (5112) and abuts against a side of the first folding edge (5111) of the outer frame (511), and the abutting member (6) abuts against a side of the first folding edge (5111).

4. A PTFE oil seal lip preload test device according to claim 3, characterized in that: The abutment member (6) includes an abutment ring (61) and an extension retaining ring (62); the second clamper (3) includes a second connecting rod (31) and a second connecting disk (32) coaxially arranged at one end of the second connecting rod (31); a collar (33) is coaxially arranged on one side of the second connecting disk (32); the abutment ring (61) is sleeved on the inner side of the collar (33); the abutment ring (61) and the collar (33) are detachably connected via a connecting member; the extension retaining ring (62) is coaxially arranged on a side of the abutment ring (61) away from the second connecting disk (32); and the extension retaining ring (62) abuts against a side of the first folded edge (5111) away from the lip (5).

5. A PTFE oil seal lip preload test device according to claim 4, characterized in that: The connecting member includes a pin (34), a first through hole (331) is provided on the collar (33), and a second through hole (611) is provided on the abutting ring (61). The pin (34) inserts and fixes the collar (33) and the abutting ring (61) through the first through hole (331) and the second through hole (611). A sliding bar (612) is provided on the outer peripheral wall of the abutting ring (61), and a sliding groove (332) is provided on the inner peripheral wall of the collar (33). The sliding bar (612) is slidably connected to the collar (33) through the sliding groove (332). A limiting member (7) for pre-positioning the abutting ring (61) is provided on the collar (33).

6. A PTFE oil seal lip preload test device according to claim 5, characterized in that: The limiting member (7) comprises a moving block (71) and a guide rod (72). The moving block (71) is slidably mounted on the collar (33) along the radial direction of the collar (33). A guide rod (72) slidably connected to the collar (33) is provided on one side of the moving block (71). A spring (73) is sleeved on the guide rod (72). One end of the guide rod (72) is located outside the collar (33). A limiting block (74) is provided on a side of the collar (33) away from the guide rod (72). An embedding groove (63) is provided on the outer peripheral wall of the abutting ring (61). The limiting block (74) is plug-connected to the abutting ring (61) through the embedding groove (63).

7. A PTFE oil seal lip preload test device according to claim 4, characterized in that: The tensile testing machine (1) is provided with identical first clamps (8) and second clamps (9) opposite to each other. The first clamps (8) and the second clamps (9) are mounted on the tensile testing machine (1) so as to slide in opposite directions. The first connecting rod (21) is detachably connected to the first clamp (8), and the second connecting rod (31) is detachably connected to the second clamp (9).

8. A PTFE oil seal lip preload test device according to claim 7, characterized in that: The first clamp (8) comprises a mounting block (81), a first clamping block (82) and a second clamping block (83); the mounting block (81) is arranged at the driving end of the hydraulic system of the tensile testing machine (1); the first clamping block (82) and the second clamping block (83) are slidably mounted on the mounting block (81) in opposite directions; the first clamping block (82) and the second clamping block (83) clamp one end of the first connecting rod (21); a rotating screw (84) is arranged on the mounting block (81); the rotating screw (84) is provided with two opposite threads; the first clamping block (82) and the second clamping block (83) are respectively threadedly connected to the rotating screw (84) at the two threads.

9. A PTFE oil seal lip preload test device according to claim 8, characterized in that: The first clamping block (82) and the second clamping block (83) are provided with arc grooves (821), and the arc grooves (821) on both sides are relatively distributed and form a cylindrical shape. When the first connecting rod (21) is clamped, the outer peripheral wall of the first connecting rod (21) abuts against the side wall of the arc groove (821) of the first clamping block (82) and the second clamping block (83). The first clamping block (82) and the second clamping block (83) are provided with positioning holes (822). The first connecting rod (21) is provided with two relatively distributed positioning columns (211), and the positioning columns (211) are plug-connected with the first clamping block (82) and the second clamping block (83) through the positioning holes (822).

10. A method for testing the preload of a PTFE oil seal lip using the PTFE oil seal lip preload testing device according to claim 1, characterized in that: The test steps include: S1, cut off the lip (5) and the accessory lip; S2, assembling the rubber pad, the lip (5) and the inner frame (512) onto the second folded edge (5112) of the outer frame (511) in sequence, and rolling the first folded edge (5111) of the outer frame (511) to press the inner frame (512) and the lip (5) to form a seal; S3. Place the assembled seal on the fixing ring (42), screw the fixing ring (42) onto the first holder (2), and calculate the compression amount of the fixing lip (5) according to the formula; Wherein, △t is the compression amount (30% to 35%), %; h2 is the height of the lower fixture, in millimeters (mm); h1 is the height of the upper fixture, in millimeters (mm); t is the thickness of the lip (5), in millimeters (mm); S4, sleeve the abutment ring (61) until it abuts against the outer diameter stopper (51) on the seal, then move the second holder (3) to the abutment ring (61), and connect the abutment ring (61) to the second holder (3) through the pin (34); S5. Connect the second clamp (3) to the second fixture (9), and connect the first clamp (2) to the first fixture (8); S6. Start the tensile testing machine (1) and pull the clamp at a certain speed to perform the test until the sealing lip (5) is detached or broken.

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