Intravascular stent bending torsion fatigue test device

Abstract

The invention discloses an intravascular stent bending torsion fatigue test device, and belongs to the technical field of fatigue test machinery. The intravascular stent bending torsional fatigue test device comprises a rack, the rack comprises a door-shaped support, a back plate and a base, the door-shaped support is provided with a bending load module, the bending load module comprises a first stepping motor, the output end of the first stepping motor penetrates through the back plate and is fixedly connected with an eccentric wheel through an extension shaft, and a pair of sliding blocks is additionally arranged; a sliding rail is arranged on the inner side of the door-shaped support, the sliding blocks are arranged on the sliding rail, a cantilever is connected between the pair of sliding blocks, the top of the cantilever is connected with the lower side of the top of the door-shaped support through a spring, a plurality of first loading connectors are arranged on the front face of the cantilever, and a torsion module is additionally arranged. The fatigue durability under bending-torsion dual loads can be tested, and the fatigue performance of the stent under the condition of blood vessel deformation during limb movement can be truly simulated.

Description

Technical Field

[0001] The present invention relates to the technical field of fatigue test machinery, and in particular to a bending and torsion fatigue test device for vascular stents. Background Art

[0002] Peripheral arterial disease (PAD) refers to the stenosis or obstruction of peripheral arteries caused by atherosclerosis, resulting in blood flow obstruction and thus ischemic symptoms and signs. Patients with atherosclerotic diseases often experience coldness, numbness, swelling and pain in the lower extremities, and intermittent claudication. They even often have clinical manifestations such as numbness of the extremities, disappearance of dorsalis pedis artery pulsation, and digital ulcers. Among them, the 5-year survival rate of diabetic patients with PAD is only 5%, and more than 200 million people around the world are deeply tortured by PAD. At present, with the rapid development of interventional therapy, the method of using vascular stents to treat PAD has been widely used clinically.

[0003] Since peripheral arterial diseases mostly occur at joints, such stents need to adapt to limb movement and meet the requirements of long-term physiological deformation behavior. At present, most studies calculate the mechanical properties and fatigue properties of vascular stents during the deformation process through finite element simulation. It is impossible to directly detect and evaluate the fatigue durability of vascular stents under complex deformations. In addition, as a small medical device, considering factors such as its special structure, function, and use environment, conventional fatigue equipment cannot be used for testing or experiments, and special fatigue equipment needs to be designed.

[0004] At present, the known such equipment includes radial fatigue test equipment and bending fatigue test equipment. The radial test equipment is used to test the fatigue performance of vascular stents under the pulsatile blood pressure load when the blood vessels contract and dilate. The latter is used to test the fatigue performance of vascular stents under bending load when the blood vessels deform. However, the actual deformation of blood vessels with limb movement is complex, and the load acting on the stent is not a single load, but the superposition of bending and torsion dual loads. Therefore, it is very necessary to design a bending and torsion fatigue test device for vascular stents that conforms to the actual situation. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems in the prior art and provide a bending and torsion fatigue test device for vascular stents.

[0006] The present invention provides a bending and torsional fatigue test device for vascular stents, which is used to conduct experiments on vascular stents. The device includes a frame, which comprises a gantry bracket. A bending load module is provided on the gantry bracket. The bending load module includes a pair of sliders. A slide rail is provided inside the gantry bracket, and the sliders are placed on the slide rail. A horizontally arranged cantilever is fixedly connected between the pair of sliders. The top of the cantilever is fixedly connected to the lower side of the top of the gantry bracket through a spring. A number of first loading joints are arranged on the front of the cantilever. A propulsion component is provided on one side of the cantilever, and the propulsion component is used to push the cantilever reciprocally. In addition, a torsional load module is provided. The torsional end of the torsional load module is fixedly connected with a number of second loading heads. The vascular stent is implanted in the middle part of an artificial blood vessel, and both ends of the artificial blood vessel are connected to the first loading joints and the second loading heads respectively. The torsional load module is used to rotate the artificial blood vessel in the horizontal direction.

[0007] Preferably, the frame further includes a backboard and a base. The gantry bracket is vertically installed on the base, and the gantry bracket and the backboard are fixed to the top of the base. The propulsion component includes a first stepping motor, which is fixedly connected to the outside of the backboard. The output end of the first stepping motor passes through the backboard and is connected with an eccentric wheel through an extension shaft.

[0008] Preferably, a counting detection disk is sleeved on the output end of the first stepping motor. The counting detection disk is placed between the eccentric wheel and the backboard. A limit sensor is arranged on the top of the counting detection disk, and the limit sensor is fixedly connected to the backboard. The first stepping motor, the counting detection disk and the limit sensor are electrically connected to a control module.

[0009] Preferably, a deep groove ball bearing is arranged at the middle position of the cantilever, and the top of the deep groove ball bearing abuts against the eccentric wheel.

[0010] Preferably, an elliptical groove hole is formed on the eccentric wheel. The output end of the first stepping motor is placed in the elliptical groove hole and is fixedly connected with the extension shaft. Two planes are milled at the middle step of the extension shaft to cooperate with the elliptical groove hole.

[0011] Preferably, the torsional load module includes a second stepping motor, which is fixedly connected to the lower end of the base. The output end of the second stepping motor is fixedly connected with a second loading head through a setscrew.

[0012] Preferably, a constant temperature module is further provided. The constant temperature module includes a constant temperature cover which covers the outside of the portal frame. A heating water tank is fixedly connected to the outside of the constant temperature cover. The output end of the heating water tank is connected to the input end of a pressure pump. The left and right sides inside the constant temperature cover are evenly provided with heat conduction pipes. The output end of the heat conduction pipe is connected to the input end of the heating water tank and the output end of the pressure pump is connected thereto. A temperature sensor is provided on the constant temperature cover.

[0013] Preferably, both ends of the artificial blood vessel are respectively fixed to the first loading joint and the second loading joint through hose clamps.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: For a blood vessel stent bending and torsion fatigue test device of the present invention, when in use, the up and down cyclic bending movement of the artificial blood vessel is realized through the bending load module, and the torsion movement of the silicone artificial blood vessel is realized through the torsion load module. Bending, torsion and bending-torsion fatigue tests with different bending angles and torsion angles can be carried out. It can test not only the fatigue life of the blood vessel stent under bending and torsion deformation, but also the fatigue durability under the dual loads of bending and torsion. It can more realistically simulate the fatigue performance of the stent under the deformation of the blood vessel during limb movement. The device has the characteristics of wide applicability, simple structure, simple operation and convenient use.

[0015] In the present invention, the heating water tank heats the constant temperature liquid to a set temperature, and the pressure pump is used to realize the cyclic flow of the constant temperature liquid in the heat conduction pipes, continuously heating the inside of the constant temperature cover to maintain the temperature required for the test environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the working principle diagram of the blood vessel stent bending and torsion fatigue test of the embodiment of the present invention;

[0017] Figure 2 is the three-dimensional structure diagram of the blood vessel stent bending and torsion fatigue test device of the embodiment of the present invention;

[0018] Figure 3 is the front view of the blood vessel stent bending and torsion fatigue test device of the embodiment of the present invention;

[0019] Figure 4 is the side view of the blood vessel stent bending and torsion fatigue test device of the embodiment of the present invention;

[0020] Figure 5 is the structural schematic diagram of the limit sensor and the counting detection disc of the embodiment of the present invention;

[0021] Figure 6 is the structural schematic diagram of the eccentric wheel of the embodiment of the present invention;

[0022] Figure 7 is the structural schematic diagram of the cantilever of the embodiment of the present invention;

[0023] Figure 8 This is a schematic diagram of the extension shaft structure of the embodiment of the present invention.

[0024] Explanation of reference numerals in the drawings: 1, frame; 101, gantry bracket; 102, back panel; 103, base; 2, bending load module; 201, slider; 202, slide rail; 203, cantilever; 204, first loading joint; 205, spring; 3, torsional load module; 301, second stepping motor; 302, second loading joint; 4, propulsion assembly; 401, first stepping motor; 402, extension shaft; 403, eccentric wheel; 5, limit sensor; 6, counting detection disk; 7, deep groove ball bearing; 8, elliptical slot hole; 9, constant temperature module; 901, constant temperature cover; 902, temperature sensor; 10, control module; 11, vascular stent; 12, artificial blood vessel. Detailed implementation manners

[0025] The following combines the attached Figure 1-8 To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meaning understood by those of ordinary skill in the art in the field to which the present invention belongs.

[0026] The "first", "second", and similar terms used in the description and claims of this patent application of the present invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "inside", "outside", "above", "below", "far", "near", "front", "rear", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly. The drawings in this disclosure are not strictly drawn to actual scale, and the specific dimensions and quantities of each structure can be determined according to actual needs. The drawings described in this disclosure are only schematic diagrams.

[0027] A bending and torsional fatigue test device for a vascular stent 11 provided by the present invention, as Figure 1-8As shown in the figure, it includes a frame 1. The frame 1 includes a gantry bracket 101, a back plate 102 and a base 103. The gantry bracket 101 is vertically installed on the base 103. The gantry bracket 101 and the back plate 102 are fixed to the top of the base 103 with angle irons and bolts. A bending load module 2 is provided on the gantry bracket 101. The bending load module 2 includes a first stepping motor 401. The first stepping motor 401 is fixedly connected to the outside of the back plate 102. The output end of the first stepping motor 401 passes through the back plate 102 and is fixedly connected with an eccentric wheel 403 through an extension shaft 402. Additionally, a pair of sliders 201 is provided. A slide rail 202 is provided on the inner side of the gantry bracket 101. The sliders 201 are placed on the slide rail 202. A cantilever 203 is fixedly connected between the pair of sliders 201. The top of the cantilever 203 is fixedly connected to the lower side of the top of the gantry bracket 101 through a spring 205. A number of first loading joints 204 are arranged on the front of the cantilever 203. Additionally, a torsional load module 3 is provided. The torsional load module 3 is used to rotate the artificial blood vessel 12 in the horizontal direction. A bearing is provided at the middle position of the back plate 102. The top of the bearing abuts against the eccentric wheel 403. An elliptical groove hole 8 is opened on the eccentric wheel 403. The output end of the first stepping motor 401 is placed in the elliptical groove hole 8 and is fixedly connected with the extension shaft 402. Two planes are milled at the middle step of the extension shaft 402 to cooperate with the elliptical groove hole 8.

[0028] In the present invention, according to the usage situation, the eccentricity of the provided eccentric wheel 403 is adjusted. After the adjustment is completed and during use, the first stepping motor 401 drives the provided eccentric wheel 403 to rotate through the extension shaft 402. After the eccentric wheel 403 presses against the cantilever 203 through the bearing, the cantilever 203 will move downward. The cantilever 203 will drive the artificial blood vessel to move downward together through the first loading head with the assistance of the slider 201, thus forming a bending force. When the cantilever 203 moves downward, it will simultaneously pull the provided spring 205. When the shorter radius side of the eccentric wheel 403 rotates to one side of the cantilever 203, the cantilever 203 will move upward under the action of the stretched spring 205. Combining with the spring 205 to realize the up-and-down cyclic translational movement of the cantilever 203, the bending angle of the stent can be 0 - 180°, preferably 30 - 150°.

[0029] In the present invention, the cantilever 203 is designed as a hollow structure, which is beneficial to reducing the weight and reducing the load on the spring 205 during the fatigue test. A deep groove ball bearing 7 is provided at the middle position of the top end of the cantilever 203 to contact the eccentric wheel 403, reducing the frictional resistance. In order to prevent the first loading joint 204 from loosening when the artificial blood vessel 12 is torsionally deformed, a split design and a set screw fixation are adopted simultaneously, which can meet stents of different diameter sizes.

[0030] Preferably, as Figure 3-8As shown in the figure, a counting detection disk 6 is sleeved on the output end of the first stepping motor 401. The counting detection disk 6 is placed between the eccentric wheel 403 and the back plate 102. A limit sensor 5 is provided at the top of the counting detection disk 6. The limit sensor 5 is fixedly connected to the back plate 102. The first stepping motor 401, the counting detection disk 6 and the limit sensor 5 are electrically connected to a control module 10. The top of the bearing abuts against the eccentric wheel 403.

[0031] A square hole is provided at the edge position of the counting detection disk 6, which is matched with the limit sensor 5. When the counting detection disk 6 rotates one week, the square hole is recorded once when it passes through the limit sensor 5, which is used for recording the number of load times.

[0032] Preferably, as Figure 1-3 shown, the torsion load module 3 includes a second stepping motor 301. The second stepping motor 301 is fixedly connected to the lower end of the base 103. The output end of the second stepping motor 301 is fixedly connected with a second loading joint 302 through a setscrew.

[0033] The second stepping motor 301 is electrically connected to the control module 10. The second loading joint 302 can be replaced according to the requirements of blood vessel stents 11 with different diameters. When the second stepping motor 301 rotates at a set angle, a cyclic torsion motion can be realized. The torsion angle of the stent is 0-360°. When the bending load module 2 and the torsion load module 3 work simultaneously, the artificial blood vessel 12 can simultaneously undergo cyclic bending and torsional deformation, and such deformation is more in line with the real deformation of blood vessels during limb movement.

[0034] Preferably, as Figure 1-4 shown, there is also a constant temperature module 9. The constant temperature module 9 includes a constant temperature cover 901. The constant temperature cover 901 covers the outside of the gantry bracket 101. A heating water tank is fixedly connected to the outside of the constant temperature cover 901. The output end of the heating water tank is connected to the input end of a pressure pump. The heat conduction pipes are evenly arranged in a coil on the left and right sides inside the constant temperature cover 901. The output end of the heat conduction pipe is connected to the input end of the heating water tank, and the output end of the pressure pump is connected. A temperature sensor 902 is provided on the constant temperature cover 901.

[0035] The heating water tank heats the constant temperature liquid to the set temperature, and the pressure pump is used to realize the cyclic flow of the constant temperature liquid in the heat conduction pipes, continuously heating the inside of the constant temperature cover 901 to maintain the temperature required for the test environment.

[0036] Preferably, as Figure 1-4 shown, the control module 10 includes a human-machine interface, a controller, a stepping drive circuit, a detection and alarm circuit, and a constant temperature control circuit. The temperature, frequency, number of load times, and torsion angle can be set through the human-machine interface.

[0037] The temperature, frequency, number of load cycles, and torsional angle can be set through the human-machine interaction interface. Among them, the controllable range is: temperature 30 - 100 °C, frequency 0 - 100 Hz, number of load cycles 0 - 400 million times, which is equivalent to the pulsating cyclic load of the human body for 10 years.

[0038] Preferably, both ends of the artificial blood vessel 12 are respectively fixed to the first loading joint 204 and the second loading joint 302 through hose clamps.

[0039] The vascular stent 11 is implanted in the middle part of the artificial blood vessel 12, and both ends of the artificial blood vessel 12 are respectively fixed to the first loading joint 204 and the second loading joint 302 through hose clamps.

[0040] The usage method of the bending and torsional fatigue test device for the vascular stent 11 of the present invention is as follows:

[0041] 1) Select the loading joint and the diameter of the artificial blood vessel 12 according to the size of the test sample, adjust the installation positions of the first stepping motor 401 and the second stepping motor 301, calculate the stroke of the cantilever 203 according to the bending angle, adjust the eccentricity of the eccentric wheel 403, and check whether the electrical components are working properly.

[0042] 2) Release the vascular stent 11 in the middle part of the artificial blood vessel 12, and observe that there should be no skewing, extrusion deformation, etc. between the vascular stent 11 and the external artificial blood vessel 127.

[0043] 3) Visually observe the vascular stent 11 and record whether abnormal phenomena such as deformation and fracture are found.

[0044] 4) Mark the position and number of the stent on the artificial blood vessel 12.

[0045] 5) Install both ends of the artificial blood vessel 12 equipped with the vascular stent 11 to the first loading head and the second loading joint 302 respectively through hose clamps.

[0046] 6) Turn on the temperature control system through the human-machine interaction interface, adjust the temperature to 37 °C ± 2 °C, set the frequency to 30 Hz, the number of load cycles to 1 million times, the torsional angle to 38.5 °, and turn on each test part in sequence. The device records the test frequency and the fatigue number of the sample test.

[0047] 7) According to the counting feedback, set the performance indicators of the stent for shutdown testing every 1 million times: integrity, surface defect condition.

[0048] 8) Based on the above bending and torsional fatigue test methods, measure the sample after bending and torsional fatigue tests. The test frequencies are: 1 million times, 2 million times, 3 million times, 4 million times, 5 million times, 6 million times, 7 million times, 8 million times, 9 million times, 10 million times.

[0049] Test requirements: Remove the test bracket every 1 million times (±10,000 times) of shutdown, observe the inner and outer surfaces of the bracket under a high-power microscope, and determine whether there are integrity losses such as fractures and collapses. Take photos of the bracket with an optical measuring instrument.

[0050] The performance indicators are as follows: 1) Requirements for the fatigue test item: ≥10 million times; 2) The tested bracket is required to check the integrity and surface defects of the bracket under the condition of magnification ≥10 times.

[0051] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A bending and torsional fatigue test device for a vascular stent, which is used to conduct experiments on a vascular stent (11), including a frame (1), and the frame (1) includes a portal frame (101), and is characterized in that, A bending load module (2) is provided on the gantry bracket (101); The bending load module (2) includes a pair of sliders (201). A slide rail (202) is provided inside the gantry bracket (101). The sliders (201) are placed on the slide rail (202). A horizontally arranged cantilever (203) is fixedly connected between the pair of sliders (201). The top of the cantilever (203) is fixedly connected to the lower side of the top of the gantry bracket (101) through a spring (205). A number of first loading joints (204) are arranged on the front surface of the cantilever (203). A propulsion assembly (4) is provided on one side of the cantilever (203). The propulsion assembly (4) is used to reciprocally push the cantilever (203); A torsional load module (3) is additionally provided. The torsional end of the torsional load module (3) is fixedly connected with a number of second loading joints (302). The vascular stent (11) is implanted in the middle part of the artificial blood vessel (12). The two ends of the artificial blood vessel (12) are respectively connected to the first loading joint (204) and the second loading head (302). The torsional load module (3) is used to rotate the artificial blood vessel (12) in the horizontal direction.

2. The vascular stent bending and torsional fatigue test device according to claim 1, wherein, The frame (1) further includes a back plate (102) and a base (103). The gantry bracket (101) is vertically installed on the base (103). The gantry bracket (101) and the back plate (102) are fixed to the top of the base (103). The propulsion assembly (4) includes a first stepping motor (401). The first stepping motor (401) is fixedly connected to the outside of the back plate (102). The output end of the first stepping motor (401) passes through the back plate (102) and is connected with an eccentric wheel (403) through an extension shaft (402).

3. The bending and torsional fatigue test device for a vascular stent according to claim 1, characterized in that, A counting detection disk (6) is sleeved on the output end of the first stepping motor (401). The counting detection disk (6) is placed between the eccentric wheel (403) and the back plate (102). A limit sensor (5) is provided on the top of the counting detection disk (6). The limit sensor (5) is fixedly connected to the back plate (102). The first stepping motor (401), the counting detection disk (6) and the limit sensor (5) are electrically connected to a control module (10).

4. The vascular stent bending and torsion fatigue test device according to claim 3, characterized in that A deep groove ball bearing (7) is provided at the middle position of the cantilever (203). The top of the deep groove ball bearing (7) abuts against the eccentric wheel (403).

5. The vascular stent bending and torsional fatigue test device according to claim 3, characterized in that, An elliptical groove hole (8) is formed on the eccentric wheel (403). The output end of the first stepping motor (401) is placed in the elliptical groove hole (8) and is fixedly connected with the extension shaft (402). Two planes are milled at the middle step of the extension shaft (402) to cooperate with the elliptical groove hole (8).

6. The bending and torsional fatigue test device for a vascular stent according to claim 3, wherein, The torsional load module (3) includes a second stepping motor (301). The second stepping motor (301) is fixedly connected to the lower end of the base (103). The output end of the second stepping motor (301) is fixedly connected with the second loading joint (302) through a setscrew.

7. The bending and torsional fatigue test device for a vascular stent according to claim 4, characterized in that, A constant temperature module (9) is further provided. The constant temperature module (9) includes a constant temperature cover (901). The constant temperature cover (901) is sleeved outside the portal bracket (101). A heating water tank is fixedly connected to the outside of the constant temperature cover (901). The output end of the heating water tank is connected to the input end of a pressure pump. The left and right sides inside the constant temperature cover (901) are evenly provided with heat conduction pipes. The output end of the heat conduction pipe is connected to the input end of the heating water tank and the output end of the pressure pump is connected thereto. A temperature sensor (902) is provided on the constant temperature cover (901).

8. The vascular stent bending and torsional fatigue test device according to claim 6, characterized in that, Both ends of the artificial blood vessel (12) are respectively fixed to the first loading joint (204) and the second loading joint (302) through hose clamps.

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