Artificial hip joint fatigue testing device
By designing an artificial hip joint fatigue testing device that simulates human movement trajectory and load, the problem of insufficient power for complex trajectories and variable loads in existing technologies has been solved, achieving precise hip joint fatigue testing and providing reliable test data and multi-purpose testing functions.
Patent Information
- Application Number
- CN202610679759.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-18
- Publication Date
- 2026-08-25
AI Technical Summary
Existing hip joint testing platforms have shortcomings in simulating complex trajectories and varying load dynamics, making it difficult to accurately reflect the convex-concave spherical contact fit, multi-directional composite sliding friction, physiological lubrication environment, and cyclic loading of artificial hip joints, leading to deviations in fatigue test results.
Design an artificial hip joint fatigue testing device, including a frame, a Z-axis hydraulic cylinder, a simulated acetabular seat, a horizontal displacement mechanism, and a force sensor. By simulating human motion trajectory and load, combined with a lubricating fluid cup, it accurately simulates the wear and fatigue degree of the artificial hip joint.
It achieves accurate simulation of multi-directional composite sliding friction and physiological lubrication environment of artificial hip joint, provides reliable test data, supports static strength, fatigue strength and wear tests, and reduces costs.
Smart Images
Figure CN122631334A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical devices, and in particular to a fatigue testing device for artificial hip joints. Background Technology
[0002] Human joints can become diseased or damaged for various reasons, causing pain and inconvenience to patients. To improve patients' quality of life and alleviate their pain, joint replacement surgery can be performed to replace damaged joints.
[0003] The human hip joint is a complex weight-bearing joint that bears tensile, compressive, torsional, and interfacial shear forces, as well as fatigue and wear. Therefore, artificial hip joints used to replace human hip joints must also ensure their strength and service life. This necessitates static strength testing, fatigue testing, and wear testing of artificial hip joints.
[0004] Currently, domestic and international hip joint testing platforms still have some shortcomings in complex trajectory simulation and variable load dynamics. They cannot accurately reflect the convex and concave spherical contact fit, multi-directional composite sliding friction, physiological lubrication environment, and cyclic loading of artificial hip joints. These differences can lead to discrepancies between the contact stress conditions between joint kinematic pairs and reality, resulting in deviations in fatigue test results.
[0005] Therefore, a method or apparatus is needed to solve the above problems. Summary of the Invention
[0006] The present invention addresses the aforementioned shortcomings of existing technologies by proposing a simple, ingeniously designed, and rationally laid-out experimental device that can accurately simulate the human body environment and movement process, and simultaneously test the wear and tear of the femoral head and the fatigue of the femoral stem under repeated loading in artificial hip joints.
[0007] The technical solution of the present invention is: an artificial hip joint fatigue testing device, comprising a frame 1, characterized in that: a Z-axis hydraulic cylinder 2 is provided at the bottom of the frame 1, the top end of the Z-axis hydraulic cylinder 2 is connected to the bottom end of a simulated acetabular seat 3, a central support plate 4 is provided in the middle of the frame 1, a guide sleeve 5 is provided on the central support plate 4, the simulated acetabular seat 3 is slidably connected to the guide sleeve 5 through a linear bearing 6, a lubricating fluid cup 7 and a simulated acetabulum 8 are provided at the top end of the simulated acetabular seat 3, the simulated acetabulum 8 is located inside the lubricating fluid cup 7, and the simulated acetabulum 8 is connected to the spherical surface of the artificial femoral head 10 in the artificial hip joint 9. The top of the frame 1 is provided with a top support plate 11, and a horizontal displacement mechanism 12 is provided on the top support plate 11. The actuator of the horizontal displacement mechanism 12 is movably connected to the top end of the artificial femoral stem 14 in the artificial hip joint 9 through a universal joint 13. The horizontal displacement mechanism 12 includes an X-axis hydraulic cylinder 15 fixedly mounted on a top support plate 11. The working end of the X-axis hydraulic cylinder 15 is connected to an X-axis slide 16. The two ends of the X-axis slide 16 are slidably connected to X-axis guide posts 18 fixedly mounted on the top support plate 11 via X-axis guide sleeves 17. A Y-axis hydraulic cylinder 19 is provided on the bottom surface of the X-axis slide 16. The working direction of the Y-axis hydraulic cylinder 19 is perpendicular to the X-axis hydraulic cylinder 15. The working end of the Y-axis hydraulic cylinder 19 is connected to an execution slide 20. The two ends of the execution slide 20 are slidably connected to Y-axis guide posts 22 fixedly mounted on the bottom surface of the X-axis slide 16 via Y-axis guide sleeves 21. The execution slide 20 is movably connected to the top end of the artificial femoral stem 14 in the artificial hip joint 9 via a universal joint 13.
[0008] A force sensor 23 is installed between the output shaft of the Z-axis hydraulic cylinder 2 and the simulated acetabular seat 3. At the same time, a displacement sensor 24 that can move synchronously with its output shaft is also connected to the cylinder part of the Z-axis hydraulic cylinder 2.
[0009] A force sensor 23 is provided between the working end of the X-axis hydraulic cylinder 15 and the X-axis slide 16. At the same time, a displacement sensor 24 that can move synchronously with its working end is also connected to the cylinder part of the X-axis cylinder 15.
[0010] A force sensor 23 is provided between the working end of the Y-axis hydraulic cylinder 19 and the execution slide 20. At the same time, a displacement sensor 24 that can move synchronously with its working end is also connected to the cylinder part of the Y-axis hydraulic cylinder 19.
[0011] The displacement sensor 24 is an LVDT linear displacement sensor.
[0012] The simulated acetabular seat 3 has a limiting groove 25 distributed along its axial direction on its side wall, and an anti-rotation plate 26 is provided on the bottom end surface of the middle support plate 4. The anti-rotation plate 26 has an anti-rotation protrusion 27, which is movably connected in the limiting groove 25.
[0013] Compared with the prior art, the present invention has the following advantages: This artificial hip joint fatigue testing device features a simple structure, ingenious design, and rational layout. It addresses various problems inherent in traditional artificial hip joint fatigue testing by employing a unique structure. First, it uses a horizontal displacement mechanism to alter the posture of the artificial hip joint, simulating the complex trajectory of the artificial femoral head during activities such as walking, running, jumping, and climbing stairs, thus providing a more realistic simulation of the artificial hip joint's movement patterns. Second, it uses a Z-axis hydraulic cylinder to simulate the body weight and apply this load to the artificial hip joint, thereby simulating the stress on the artificial hip joint during human movement. Both of these aspects provide more reliable test data for the clinical application of artificial hip joints. Furthermore, this device can perform static strength tests, fatigue strength tests, wear tests, and motion modal tests on the artificial hip joint in different modes, offering multiple functions in one machine and effectively saving costs. In conclusion, this device possesses numerous advantages and is particularly suitable for widespread application in this field, with a very broad market prospect. Attached Figure Description
[0014] Figure 1 This is a front view of an embodiment of the present invention.
[0015] Figure 2 This is a side view of an embodiment of the present invention.
[0016] Figure 3 This is a schematic diagram of the horizontal displacement mechanism in an embodiment of the present invention.
[0017] Figure 4 This is a schematic diagram of the X-axis hydraulic cylinder in an embodiment of the present invention.
[0018] Figure 5 This is a schematic diagram of the Y-axis hydraulic cylinder in an embodiment of the present invention. Detailed Implementation
[0019] Specific embodiments of the present invention will now be described in conjunction with the accompanying drawings. Figures 1 to 5 The diagram shows a fatigue testing device for an artificial hip joint, comprising a frame 1 as a base. A Z-axis hydraulic cylinder 2 is disposed at the bottom of the frame 1, with its top end connected to the bottom end of a simulated acetabulum 3. A central support plate 4 is disposed in the middle of the frame 1, and a guide sleeve 5 is disposed on the central support plate 4. The simulated acetabulum 3 is slidably connected to the guide sleeve 5 via a linear bearing 6. A lubricating fluid cup 7 and a simulated acetabulum 8 are disposed at the top end of the simulated acetabulum 3, with the simulated acetabulum 8 located inside the lubricating fluid cup 7. The simulated acetabulum 8 is spherically connected to the artificial femoral head 10 in the artificial hip joint 9. The top of the frame 1 is provided with a top support plate 11, and a horizontal displacement mechanism 12 is provided on the top support plate 11. The actuator of the horizontal displacement mechanism 12 is movably connected to the top end of the artificial femoral stem 14 in the artificial hip joint 9 through a universal joint 13. The horizontal displacement mechanism 12 includes an X-axis hydraulic cylinder 15 fixedly mounted on a top support plate 11. The working end of the X-axis hydraulic cylinder 15 is connected to an X-axis slide 16. The two ends of the X-axis slide 16 are slidably connected to X-axis guide posts 18 fixedly mounted on the top support plate 11 via X-axis guide sleeves 17. A Y-axis hydraulic cylinder 19 is provided on the bottom surface of the X-axis slide 16. The working direction of the Y-axis hydraulic cylinder 19 is perpendicular to the X-axis hydraulic cylinder 15. The working end of the Y-axis hydraulic cylinder 19 is connected to an execution slide 20. The two ends of the execution slide 20 are slidably connected to Y-axis guide posts 22 fixedly mounted on the bottom surface of the X-axis slide 16 via Y-axis guide sleeves 21. The execution slide 20 is movably connected to the top end of the artificial femoral stem 14 in the artificial hip joint 9 via a universal joint 13.
[0020] A force sensor 23 is installed between the output shaft of the Z-axis hydraulic cylinder 2 and the simulated acetabular seat 3. At the same time, a displacement sensor 24 that can move synchronously with its output shaft is also connected to the cylinder part of the Z-axis hydraulic cylinder 2.
[0021] A force sensor 23 is provided between the working end of the X-axis hydraulic cylinder 15 and the X-axis slide 16. At the same time, a displacement sensor 24 that can move synchronously with its working end is also connected to the cylinder part of the X-axis cylinder 15.
[0022] A force sensor 23 is provided between the working end of the Y-axis hydraulic cylinder 19 and the execution slide 20. At the same time, a displacement sensor 24 that can move synchronously with its working end is also connected to the cylinder part of the Y-axis hydraulic cylinder 19.
[0023] The displacement sensor 24 is an LVDT linear displacement sensor.
[0024] The simulated acetabular seat 3 has a limiting groove 25 distributed along its axial direction on its side wall, and an anti-rotation plate 26 is provided on the bottom end surface of the middle support plate 4. The anti-rotation plate 26 has an anti-rotation protrusion 27, which is movably connected in the limiting groove 25.
[0025] The working process of the artificial hip joint fatigue testing device in this embodiment of the invention is as follows: First, take the artificial hip joint 9 that needs to be fatigue tested and install it in this device. Specifically, the artificial femoral head 10 on it is connected to the spherical surface of the simulated acetabulum 8. At the same time, inject sufficient lubricating fluid into the lubricating fluid cup 7 and use the universal joint 13 to connect the execution end (i.e., the execution slide 20) of the horizontal displacement mechanism 12 to the top end of the artificial femoral stem 14. The preparation work is completed. When fatigue testing of the artificial hip joint 9 is required, the control system sends signals to each actuator in the device, and the working end of the Z-axis cylinder 2 applies an upward force to the simulated acetabular seat 3. This force is transmitted to the artificial femoral head 10 connected to it through the simulated acetabular seat 3, thereby simulating the weight of the human body. The control system controls the horizontal displacement mechanism 12 to move, causing the top of the artificial hip joint 9 to move in the horizontal direction. Since one end of the artificial femoral head 10 cannot move in the horizontal direction, the above action will cause the artificial hip joint 9 to tilt in space. Under the action of the Z-axis hydraulic cylinder 2, the acetabular seat 3 is simulated to rise, and pressure is still applied to the artificial hip joint 9, thereby simulating the force state of the artificial hip joint 9 after it is inserted into the human body and when the human body moves. In actual operation, when the artificial femoral stem 14 is in a vertical state, its top end is set to coordinates X0 and Y0 on the plane. When the horizontal displacement mechanism 12 is activated, it drives the top end of the artificial femoral stem 14 to move sequentially to point 1 (coordinates X1 and Y1), point 2 (coordinates X2 and Y2) ... point n (coordinates Xn and Yn), and finally back to point 1. This simulates the tilting posture of the artificial hip joint 9 in different human movements. During the above process, the simulated acetabular seat 3 always applies a certain pressure to the artificial hip joint 9 (simulating human body weight). The tip of the artificial femoral stem 14 can also be moved back and forth between two points (e.g., point 1 and point 2) to simulate the tilting posture of the artificial hip joint 9 when the human body repeatedly performs a certain action. Repeat the above process until obvious cracks or damage appear on the surface of the artificial hip joint 9. Record the number of times the artificial hip joint 9 moves when the problem occurs, so as to calculate its fatigue strength. Alternatively, after a certain number of movements (such as 10,000 times), remove the artificial hip joint 9 and use auxiliary devices or instruments to check the wear of the artificial femoral head 10 and the changes in the mechanical properties of the artificial femoral stem 14, in order to determine the fatigue strength of the tested artificial hip joint 9.
[0026] The working process of the horizontal displacement mechanism 12 is as follows: When the actuator slide 20 needs to change its position in the horizontal direction, the X-axis cylinder 15 is activated, which drives the X-slide 16 and all the mechanisms on it to move along the X-axis direction. The Y-axis cylinder 19 is activated, which drives the actuator slide 20 to move along the Y-axis direction. The combination of the above two actions can realize the displacement of the actuator slide 20 (i.e. the top of the artificial hip joint 9) in the X-axis and Y-axis directions. During the longitudinal movement of the simulated acetabular seat 3, the anti-rotation protrusion 27 is slidably connected to the limiting groove 25 opened on the outside of the simulated acetabular seat 3, so the simulated acetabular seat 3 cannot rotate and can only make reciprocating linear motion along the Z-axis. When the Z-axis cylinder 2 moves, the force sensor 23, located between its output shaft and the simulated acetabulum 3, can detect the pressure applied by the Z-axis cylinder 2 to the simulated acetabulum 3 (this pressure is the pressure of the simulated acetabulum 3 on the artificial hip joint 9). Furthermore, since the working end of the displacement sensor 24 (LVDT linear displacement sensor) can move synchronously with the output shaft of the Z-axis cylinder 2, it can detect the pressure applied to the artificial hip joint 9 when the simulated acetabulum 3 moves a specific distance. Similarly, the displacement sensor 24 on the X-axis hydraulic cylinder 15 can detect the output displacement of the X-axis hydraulic cylinder 15, and the displacement sensor 24 on the Y-axis hydraulic cylinder 19 can detect the output displacement of the Y-axis hydraulic cylinder 19, thereby directly determining the motion coordinates of the top of the artificial femoral stem 14. The force sensors 23 on the X-axis cylinder 15 and the Y-axis cylinder 19 can monitor the changes in force during their movement. If the pressure detected by the force sensor 23 exceeds the preset warning value, it indicates that there is significant wear or even jamming between the mechanisms. This method can ensure the safety of the test.
Claims
1. A fatigue testing device for an artificial hip joint, comprising a frame (1), characterized in that: The bottom of the frame (1) is provided with a Z-axis hydraulic cylinder (2), the top of which is connected to the bottom of the simulated acetabular seat (3). The middle part of the frame (1) is provided with a middle support plate (4), and a guide sleeve (5) is provided on the middle support plate (4). The simulated acetabular seat (3) is slidably connected to the guide sleeve (5) through a linear bearing (6). The top of the simulated acetabular seat (3) is provided with a lubricating fluid cup (7) and a simulated acetabulum (8). The simulated acetabulum (8) is located inside the lubricating fluid cup (7), and the simulated acetabulum (8) is connected to the spherical surface of the artificial femoral head (10) in the artificial hip joint (9). The top of the frame (1) is provided with a top support plate (11), and a horizontal displacement mechanism (12) is provided on the top support plate (11). The execution end of the horizontal displacement mechanism (12) is movably connected to the top end of the artificial femoral stem (14) in the artificial hip joint (9) through a universal joint (13). The horizontal displacement mechanism (12) includes an X-axis cylinder (15) fixedly mounted on a top support plate (11). The working end of the X-axis cylinder (15) is connected to the X-axis slide (16). The two ends of the X-axis slide (16) are slidably connected to the X-axis guide column (18) fixedly mounted on the top support plate (11) via X-axis guide sleeves (17). A Y-axis cylinder (19) is provided on the bottom surface of the X-axis slide (16). The working direction of the Y-axis cylinder (19) is perpendicular to the X-axis cylinder (15). The working end of the Y-axis cylinder (19) is connected to the execution slide (20). The two ends of the execution slide (20) are slidably connected to the Y-axis guide column (22) fixedly mounted on the bottom surface of the X-axis slide (16) via Y-axis guide sleeves (21). The execution slide (20) is movably connected to the top end of the artificial femoral stem (14) in the artificial hip joint (9) via a universal joint (13).
2. The artificial hip joint fatigue testing device according to claim 1, characterized in that: A force sensor (23) is provided between the output shaft of the Z-axis cylinder (2) and the simulated acetabular seat (3). At the same time, a displacement sensor (24) that can move synchronously with its output shaft is also connected to the cylinder part of the Z-axis cylinder (2).
3. The artificial hip joint fatigue testing device according to claim 1, characterized in that: A force sensor (23) is provided between the working end of the X-axis hydraulic cylinder (15) and the X-axis slide (16), and a displacement sensor (24) that can move synchronously with its working end is also connected to the cylinder barrel of the X-axis cylinder (15).
4. The artificial hip joint fatigue testing device according to claim 1, characterized in that: A force sensor (23) is provided between the working end of the Y-axis cylinder (19) and the execution slide (20), and a displacement sensor (24) that can move synchronously with its working end is also connected to the cylinder part of the Y-axis cylinder (19).
5. The artificial hip joint fatigue testing device according to claim 2, 3, or 4, characterized in that: The displacement sensor (24) is an LVDT linear displacement sensor.
6. The artificial hip joint fatigue testing device according to claim 1, characterized in that: The simulated acetabular seat (3) has a limiting groove (25) distributed along its axial direction on its side wall. An anti-rotation plate (26) is provided on the bottom surface of the middle support plate (4). An anti-rotation protrusion (27) is provided on the anti-rotation plate (26). The anti-rotation protrusion (27) is movably connected in the limiting groove (25).