Low-speed reciprocating type curved surface friction testing machine for simulating knee joint of human body

Abstract

The invention discloses a low-speed reciprocating type curved surface friction testing machine for simulating human knee joints, and relates to the technical field of testing material friction performance, the low-speed reciprocating type curved surface friction testing machine comprises a machine body, the machine body is movably provided with an upper clamping assembly for clamping an upper experiment piece and a lower clamping assembly for clamping a lower experiment piece; the machine body is also provided with a lifting driving mechanism for driving the lower clamping assembly to move upwards, and the lifting driving mechanism drives the lower experiment piece to ascend to enable the top of the lower experiment piece to abut against the bottom of the upper experiment piece with preset pre-pressure so as to simulate the load state of the knee joint of the human body; the machine body is further provided with a swing driving device for driving the upper clamping assembly to swing back and forth, and the swing driving device drives the upper experiment piece to swing back and forth so that friction can be formed between the upper experiment piece and the lower experiment piece to simulate friction movement of the knee joint of the human body. Friction movement of a human knee joint in a load state is simulated, so that an in-vitro experiment on a human knee joint prosthesis material is realized, and medical negligence caused by unqualified materials is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of testing material friction performance, in particular to a low-speed reciprocating curved surface friction testing machine simulating a human knee joint. Background Art

[0002] With the continuous advancement of industrial technology, tribology plays a key role in many fields, such as machinery, automobiles, aerospace, electronics, etc. In these fields, friction testing machines, as an important research equipment, are widely used to study the friction properties of material surfaces, the performance evaluation of lubricants, the study of friction and wear mechanisms, etc. The application of friction testing machines covers many aspects such as industrial needs, scientific and technological development, and product quality control, reducing the losses and risks caused by friction and wear. With the continuous advancement of science and technology and the continuous development of industry, the research and application of friction testing machines will continue to deepen and expand.

[0003] In recent years, friction testing machines have been developing continuously both at home and abroad, but there are few studies on friction testing of artificial knee joints. Therefore, there is no suitable curved surface friction testing machine to realize friction testing of human knee joint prosthesis materials, which leads to the application of unqualified materials in the human body, resulting in medical accidents. Summary of the invention

[0004] The purpose of the present invention is to provide a low-speed reciprocating curved surface friction testing machine that simulates the human knee joint. By simulating the friction movement of the human knee joint under load, in vitro experiments on human knee joint prosthesis materials can be carried out, thereby avoiding medical accidents caused by unqualified materials.

[0005] In order to achieve the above object, the technical solution of the present invention is: The present invention discloses a low-speed reciprocating curved surface friction testing machine for simulating a human knee joint, comprising a machine body, on which an upper clamping assembly for clamping an upper test piece and a lower clamping assembly for clamping a lower test piece are movably mounted; the machine body is also provided with a lifting drive mechanism for driving the lower clamping assembly to move upward, the lifting drive mechanism drives the lower test piece to rise so that its top is pressed against the bottom of the upper test piece with a preset pre-pressure, so as to simulate the load state of the human knee joint; the machine body is also provided with a swinging drive device for driving the upper clamping assembly to swing back and forth, the swinging drive device drives the upper test piece to swing back and forth so that friction is formed between the upper test piece and the lower test piece, so as to simulate the friction movement of the human knee joint.

[0006] After adopting the above structure, the upper test piece is clamped by the upper clamping assembly, and the lower test piece is clamped by the lower clamping assembly; then the lower test piece is driven up by the lifting drive mechanism, so that its top is pressed against the bottom of the upper test piece with a preset pre-pressure, which is used to simulate the load state of the human knee joint; then the upper test piece is driven to swing back and forth by the swing drive device, so that friction is formed between the upper test piece and the lower test piece, which is used to simulate the friction movement of the human knee joint. In this way, the friction movement of the human knee joint under load is simulated, thereby realizing the in vitro experiment of the human knee joint prosthesis material, avoiding medical accidents caused by unqualified materials.

[0007] Preferably, a spherical head is provided at the top of the lower test piece, and an arc groove is provided in the middle thereof, and an arc head is provided at the bottom of the upper test piece to be inserted into the arc groove, and the arc head swings back and forth in the arc groove, so as to simulate the movement of the human knee joint; a friction force sensor is installed in the arc groove. Through this arrangement, the upper test piece and the lower test piece can be prevented from being separated, and the friction force between the two can be accurately measured, providing data support for the simulation experiment.

[0008] Preferably, the upper clamping assembly includes a pipe clamp structure with adjustable diameter, which includes a circular ring structure with an opening at the head, a bolt hole arranged at the position of the opening at the head, and a long cylinder arranged at the tail of the circular ring structure; bolts and nuts are installed in the bolt holes, and the diameter of the circular ring structure is adjusted by the screwing length of the bolts and nuts. After adopting the above structure, the structure of the upper clamping assembly can be simplified so that the swing driving device can better drive it to swing.

[0009] Preferably, the swing drive device includes a reduction motor arranged on the machine body and a crank rocker mechanism installed on the output shaft of the reduction motor; the crank rocker mechanism includes a crank fixedly installed on the output shaft of the reduction motor, a rocker hinged on the machine body, and a connecting rod movably connected between the crank and the rocker; the connecting rod and the rocker are both rotatably installed on the long cylinder. Through this structure, the reciprocating swing of the upper clamping assembly can be stably achieved, and the crank rocker mechanism can achieve the stability of the swing curve.

[0010] Preferably, a support frame is slidably mounted on the machine body, a slide rail platform is slidably mounted on the support frame, and the lower clamping assembly is fixedly mounted on the slide rail platform. Through this structure, the lower clamping assembly can be stably lifted and lowered, and its position accuracy can be improved.

[0011] Preferably, the lifting drive mechanism comprises a lifting drive device arranged between the machine body and the support frame and a load simulation device arranged between the support frame and the slide rail platform. Through this structure, damage to the material can be avoided.

[0012] Preferably, the lifting drive device includes a lead screw rotatably mounted at the bottom of the machine body and a lifting motor fixedly mounted at the bottom of the machine body to drive the lead screw to rotate; the lead screw extends vertically upward and never contacts the slide rail platform; a lead screw nut is screwed on the lead screw; the lead screw nut is fixed on the support frame. The lifting of the support frame is controlled by the lead screw nut, thereby achieving controllability of the lifting accuracy.

[0013] Preferably, the load simulation device includes a loading spring clamped between the support frame and the slide rail platform; a pressure sensor is provided at the bottom of the slide rail platform corresponding to the top of the loading spring. Through this structure, when the upper test piece and the lower test piece rotate, it can always ensure that there is a load between the two, and automatically adjust the load size to avoid damage to the materials of the upper test piece and the lower test piece.

[0014] Preferably, the lower clamping assembly includes a fixture base fixed on the slide rail platform, two slides on the slidably mounted fixture base, and a sliding drive device for driving the two slides to move relative to or opposite to each other; a V-shaped block is fixedly mounted on each slide, the two V-shaped blocks are arranged opposite to each other, and the lower test piece is clamped between the two V-shaped blocks. Through this structure, a stable clamping of the lower test piece is achieved.

[0015] Preferably, the test machine housing is also included to cover all the internal components; a partition is provided at the middle and lower part of the test machine housing to install the machine body, and the lifting motor is installed in the space under the partition. Through this structure, the internal structure can be well protected.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are: The invention discloses a low-speed reciprocating curved surface friction testing machine simulating a human knee joint, which solves the technical problem in the prior art that it is impossible to conduct in vitro simulation testing on the qualification of human knee joint materials, thereby causing medical accidents. The invention simulates the friction movement of the human knee joint under load, thereby realizing in vitro experiments on human knee joint prosthesis materials, thereby avoiding medical accidents caused by unqualified materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a low-speed reciprocating curved surface friction testing machine simulating a human knee joint of the present invention; Figure 2 yes Figure 1 A half-section view of Figure 3 yes Figure 1 The side view after removing the testing machine housing; Figure 4 yes Figure 3 Isometric structural diagram of the Figure 5 yes Figure 3 A front view of Figure 6 is a schematic diagram of the structure of the lower clamping assembly; Figure 7 yes Figure 6 A top view of Figure 8 yes Figure 7 Sectional view of AA in the middle; Fig. 9 This is a schematic diagram of the cooperation of the outer slide rail, the inner slide rail and the inner slide rail platform in the present invention. Figure 1 ; In the figure, 1. body, 11. outer slide rail, 2. upper test piece, 3. lower test piece, 4. upper clamping assembly, 41. circular ring structure, 42. bolt hole, 43. long cylinder, 5. lower clamping assembly, 51. fixture base, 52. slide table, 53. stud, 54. V-block, 6. lifting drive mechanism, 61. support frame, 611. inner slide rail, 62. slide rail platform, 63. lifting drive device, 631. lifting motor, 632. lead screw, 633. lead screw nut, 64. load simulation device, 7. swing drive device, 71. reduction motor, 72. crank rocker mechanism, 721. crank, 722. rocker, 723. connecting rod, 724. hinge support, 8. friction sensor. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] The orientations mentioned in this specification are based on the orientations of the low-speed reciprocating curved surface friction testing machine simulating the human knee joint of the present invention during normal operation, and do not limit the orientations during storage and transportation. They only represent relative positional relationships, not absolute positional relationships.

[0020] like Figure 1 - Fig. 9 As shown in the figure, a low-speed reciprocating curved surface friction tester simulating a human knee joint comprises a machine body 1, on which an upper clamping assembly 4 for clamping an upper test piece 2 and a lower clamping assembly 5 for clamping a lower test piece 3 are movably mounted. The machine body 1 is also provided with a lifting drive mechanism 6 for driving the lower clamping assembly 5 to move upward, and the lifting drive mechanism 6 drives the lower test piece 3 to rise so that its top is pressed against the bottom of the upper test piece 2 with a preset pre-pressure, so as to simulate the load state of the human knee joint. The machine body 1 is also provided with a swinging drive device 7 for driving the upper clamping assembly 4 to swing back and forth, and the swinging drive device 7 drives the upper test piece 2 to swing back and forth so that friction is formed between the bottom of the upper test piece 2 and the lower test piece 3, so as to simulate the friction movement of the human knee joint.

[0021] The swinging mode of the upper test piece 2 is as follows Figure 5In the direction of the middle arrow, it swings back and forth in the direction of the arrow with the lower test piece 3 as the support point. A spherical head is provided on the top of the lower test piece 3, and an arc groove is provided in the middle position. An arc head is provided at the bottom of the upper test piece 2 to be inserted into the arc groove. The arc head swings back and forth in the arc groove, thereby simulating the movement of the human knee joint. In order to more accurately measure the friction between the two, a friction sensor 8 is installed in the arc groove.

[0022] The upper clamping assembly 4 includes a pipe clamp structure with adjustable diameter, which includes a circular ring structure 41 with an opening at the head, a bolt hole 42 arranged at the position of the opening at the head, and a long cylinder 43 arranged at the tail of the circular ring structure 41. The bolt hole 42 is installed with a bolt and a nut, and the diameter of the circular ring structure 41 is adjusted by the screwing length of the bolt and the nut to clamp the upper experimental piece 2 inside.

[0023] The swing drive device 7 includes a reduction motor 71 arranged on the machine body 1 and a crank rocker mechanism 72 installed on the output shaft of the reduction motor 71; the reduction motor 71 is fixed to the machine body 1 through a motor base, and the crank rocker mechanism 72 includes a crank 721 fixedly installed on the output shaft of the reduction motor 71, a rocker 722 hinged on the machine body 1, and a connecting rod 723 movably connected between the crank 721 and the rocker 722; one end of the connecting rod 723 and the rocker 722 are both rotatably installed on the long cylinder 43 to form a revolving pair. The output shaft of the reduction motor 71 is fixedly connected to the crank 721 through a flat key, and inner and outer sleeves are sleeved on both sides of the crank 721 to ensure sealing.

[0024] The crank 721 moves in a circular motion. In order to prevent motion interference with the output shaft of the reduction motor 71, the rotating pair connecting the crank 721 and the connecting rod 723 is designed as a pin with thin sides and a thick middle; a hinge support 724 is fixedly installed on the body 1, and the hinge support 724 is fixed to the body 1 by bolts, and the rocker 722 is rotatably installed on the hinge support 724.

[0025] A support frame 61 is slidably mounted on the machine body 1 , a slide rail platform 62 is slidably mounted on the support frame 61 , and the lower clamping assembly 5 is fixedly mounted on the slide rail platform 62 .

[0026] The lifting drive mechanism 6 includes a lifting drive device 63 arranged between the machine body 1 and the support frame 61 and a load simulation device 64 arranged between the support frame 61 and the slide rail platform 62 .

[0027] The machine body 1 is provided with multiple outer slide rails 11 on both sides of the support frame 61 in a mirror-symmetrical manner. In this embodiment, two outer slide rails 11 are provided on each side, and the support frame 61 is slidably mounted on the four outer slide rails 11. Two calipers are provided on the outer side of the support frame 61, and the notches of the calipers have the same shape as the slideways of the outer slide rails 11, and the left caliper is mirror-symmetrical with the right caliper, for mounting on the outer slide rails 11. Multiple inner slide rails 611 are provided on both sides of the slide rail platform 62 on the support frame 61 in a mirror-symmetrical manner. In this embodiment, two inner slide rails 611 are provided on each side, and the slide rail platform 62 is slidably mounted on the inner slide rails 611.

[0028] The lifting drive device 63 can be an electric cylinder or an electric push rod, or a worm gear lift. In this embodiment, the lifting drive device 63 includes a lead screw 632 rotatably mounted at the bottom of the body 1 and a lifting motor 631 fixedly mounted at the bottom of the body 1 to drive the lead screw 632 to rotate; the body 1 and the support frame 61 are provided with a round through hole for the lead screw 632 to pass through, and the lead screw 632 vertically passes through the body 1 and the support frame 61 upward; a lead screw nut 633 is screwed on the lead screw 632; the lead screw nut 633 is fixed on the support frame 61. The rotation of the lifting motor 631 drives the lead screw 632 to rotate, thereby driving the lead screw nut 633 to be lifted and lowered along the lead screw 632; thereby driving the support frame 61 to move up and down along the body 1.

[0029] The load simulation device 64 includes a loading spring clamped between the support frame 61 and the slide rail platform 62; a circular groove is set at the center position of the slide rail platform 62 for installing the spring base and the loading spring; the loading spring is a cylindrical coil spring, which is cylindrical, and the loading spring is coaxial with the spring base.

[0030] In order to accurately measure the preload force, a pressure sensor is provided at the bottom of the slide rail platform 62 corresponding to the top of the loading spring.

[0031] Furthermore, in order to achieve force balance, the round through hole of the body 1 and the support frame 61 is set at its center and is concentric with the spring mounting base and the loading spring. In order to avoid interference between the top of the lead screw 632 and the slide rail platform 62, the length of the lead screw 632 is set to a reasonable height so that it does not contact the slide rail platform 62 at all times.

[0032] The lower clamping assembly 5 includes a fixture base 51 fixed on the slide rail platform 62, two slides 52 slidably mounted on the fixture base 51, and a sliding drive device that drives the two slides 52 to move relative to or opposite to each other; a V-shaped block 54 is fixedly mounted on each slide 52, the two V-shaped blocks 54 are arranged opposite to each other and the lower test piece 3 is clamped between the two V-shaped blocks 54.

[0033] A trapezoidal groove is set in the upper and middle part of the clamp base 51 to limit the slide 52, and the two acute angles of the trapezoidal groove are 60°. At the same time, four bolt holes are set on the four corners of the bottom surface of the clamp base 51 to fix the clamp base 51 to the inner slide rail platform 62; the slide 52 is trapezoidal in shape, and the two acute angles of the slide 52 are both 60°, which is the same as the shape of the trapezoidal groove of the clamp base 51.

[0034] The sliding drive device includes a stud 53 rotatably mounted on the fixture base 51; one end of the stud 53 is provided with a positive thread, and the other end is provided with a negative thread. A connecting sleeve is screwed on the positive thread and the negative thread respectively, and the two connecting sleeves are fixed on different slides 52 respectively.

[0035] The rotational installation method of the stud 53 can adopt the method of supporting its two ends. The installation method in this embodiment is: there is a 86mm thread on each side of the stud, and two shoulders are set in the middle of the stud; the bottom of the clamp base 51 corresponds to the middle position of the two shoulders, and a countersunk hole is set to install the stud fixing rod, and the stud fixing rod is inserted into the two shoulders of the stud 53, thereby achieving the limit of the stud 53 and preventing it from falling out. The head of the stud fixing rod is set to a circular ring structure that is more than half a circle, the middle part is a long square column, the bottom end is a flange structure, and two through holes are set on the flange to install the stud fixing rod on the clamp base 51, the axes of the two through holes are coplanar and intersect with the axes of the circular holes on the circular ring structure; the circular ring structure that is more than half a circle can be directly inserted into the two shoulders of the stud 53 to achieve support and limit of the double ends. A through hole is provided in the middle of each slide 52 to allow the stud 53 to pass through. A threaded hole is provided on both sides of the through hole near the bevel of the slide 52 to install a connecting sleeve. A threaded through hole is provided in the middle of the connecting sleeve to cooperate with the stud 53. The edge of the connecting sleeve is a flange structure and two through holes are provided to install the connecting sleeve on the slide 52. The slides 52 on both sides of the stud 53 provide support for both sides of the stud 53 to prevent it from shaking or tilting. A square column is provided at the right end of the stud 53, and the position of the slide 52 can be adjusted by rotating the square column.

[0036] A low-speed reciprocating curved surface friction tester simulating a human knee joint also includes a tester housing that encloses all internal components. The tester housing is a rectangular housing, a partition is provided at the middle and lower part for installing the machine body 1, and a lifting motor 631 is installed in the space under the partition.

[0037] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A low-speed reciprocating curved surface friction testing machine simulating a human knee joint, characterized in that: It comprises a machine body, on which an upper clamping assembly for clamping an upper experimental piece and a lower clamping assembly for clamping a lower experimental piece are movably mounted; The machine body is also provided with a lifting drive mechanism for driving the lower clamping assembly to move upward, and the lifting drive mechanism drives the lower test piece to rise so that its top is pressed against the bottom of the upper test piece with a preset pre-pressure, so as to simulate the load state of the human knee joint; The machine body is also provided with a swing driving device for driving the upper clamping assembly to swing back and forth. The swing driving device drives the upper test piece to swing back and forth to form friction between the upper test piece and the lower test piece to simulate the friction movement of the human knee joint.

2. A low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 1, characterized in that: A spherical head is arranged on the top of the lower test piece, and an arc groove is arranged in the middle position thereof; an arc head which is inserted into the arc groove is arranged on the bottom of the upper test piece, and the arc head swings back and forth in the arc groove, thereby simulating the movement of the human knee joint; a friction force sensor is installed in the arc groove.

3. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 1, characterized in that: The upper clamping assembly includes a pipe clamp structure with adjustable diameter, which includes a circular ring structure with an opening at the head, a bolt hole arranged at the opening position of the head, and a long cylinder arranged at the tail of the circular ring structure; bolts and nuts are installed in the bolt holes, and the diameter of the circular ring structure is adjusted by the screwing length of the bolts and nuts.

4. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 3, characterized in that: The swing drive device includes a reduction motor arranged on the body and a crank rocker mechanism installed on the output shaft of the reduction motor; the crank rocker mechanism includes a crank fixedly installed on the output shaft of the reduction motor, a rocker hinged on the body, and a connecting rod movably connected between the crank and the rocker; the connecting rod and the rocker are both rotatably mounted on the long cylinder.

5. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 3, characterized in that: A support frame is slidably mounted on the machine body, a slide rail platform is slidably mounted on the support frame, and the lower clamping assembly is fixedly mounted on the slide rail platform.

6. A low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 5, characterized in that: The lifting drive mechanism comprises a lifting drive device arranged between the machine body and the support frame and a load simulation device arranged between the support frame and the slide rail platform.

7. A low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 6, characterized in that: The lifting drive device includes a lead screw rotatably installed at the bottom of the machine body and a lifting motor fixedly installed at the bottom of the machine body to drive the lead screw to rotate; the lead screw extends vertically upward and never contacts the slide rail platform; a lead screw nut is screwed on the lead screw; and the lead screw nut is fixed on the support frame.

8. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 6, characterized in that: The load simulation device comprises a loading spring clamped between the support frame and the slide rail platform; a pressure sensor is arranged at the bottom of the slide rail platform corresponding to the top of the loading spring.

9. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 5, characterized in that: The lower clamping assembly includes a clamp base fixed on the slide rail platform, two slides slidably mounted on the clamp base, and a sliding drive device for driving the two slides to move relative to or opposite to each other; A V-shaped block is fixedly mounted on each slide, two V-shaped blocks are arranged opposite to each other and the lower test piece is clamped between the two V-shaped blocks.

10. The low-speed reciprocating curved surface friction testing machine simulating a human knee joint according to claim 5, characterized in that: It also includes a testing machine housing that encloses all internal components; a partition is set at the middle and lower part of the testing machine housing to install the machine body, and the lifting motor is installed in the space under the partition.

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