A coupling shaft and blood pump thereof

Abstract

The application provides a connecting shaft with low abrasion, stable transmission and long service life and a blood pump thereof, which comprises a fixed shaft and a rotating shaft rotating around the fixed shaft, a floating support unit is arranged in a cavity of the fixed shaft, the floating support unit is in abutment with the rotating shaft, and the contact positions of the rotating shaft with the fixed shaft and the floating support unit change with the stress change between the floating support unit and the rotating shaft. Through the double-ball structure and the special spring support design, the efficient, stable and low-abrasion operation of the connecting shaft is realized. Meanwhile, by adjusting the contact force of the ball and the groove, the main abrasion position can be controlled, so that the service life of the connecting shaft and the blood pump is prolonged.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a connecting shaft and its blood pump. Background Technology

[0002] As a critical transmission and connection component, the performance of the connecting shaft has a decisive impact on the stability and durability of the entire device. However, traditional connecting shaft designs often have significant shortcomings, such as severe wear and short lifespan. Specifically, traditional connecting shafts typically employ a single friction interface design. This design is prone to wear at the friction interface under prolonged operation or high stress, thus affecting the transmission performance and stability of the connecting shaft. Furthermore, because traditional connecting shafts lack an effective stress-sharing mechanism, wear tends to concentrate in a specific area under high stress, further shortening the connecting shaft's lifespan. This is especially true for Class III medical devices like blood pumps, which are inserted into the heart to assist in blood pumping. The performance of the connecting shaft determines whether the blood pump can pump blood normally, and if wear debris enters the bloodstream, it can cause complications or even endanger life. Therefore, the requirements for low wear, operational stability, and long service life are even higher. Summary of the Invention

[0003] One object of the present invention is to provide a connecting shaft with low wear, stable transmission and long service life.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a connecting shaft, including a fixed shaft and a rotating shaft that rotates around the fixed shaft, wherein a floating support unit is provided in the cavity of the fixed shaft, the floating support unit abuts against the rotating shaft, and the contact position between the rotating shaft and the fixed shaft and the floating support unit changes with the stress between the floating support unit and the rotating shaft.

[0005] The floating support unit includes a first ball and a second ball. The first ball is located near the end of the chamber, and the end of the chamber has a constriction structure with a diameter smaller than that of the first ball. A support tube is installed inside the chamber, and a spring is installed between the support tube and the bottom of the chamber. The spring is in the shape of a shallow disc with an opening facing away from the support tube. One end of the support tube abuts against the spring, and the spring abuts against a fixed shaft. The other end abuts against the second ball. A spring is sleeved on the body of the support tube, and the spring provides elastic force to drive the second ball to move in the direction of the rotation axis.

[0006] The fixed shaft is bullet-shaped at one end near the rotating shaft, comprising a conical section and a rounded end. The end of the rotating shaft has a bullet-shaped groove, with a gap between the groove and the inclined surface of the conical section. A concave spherical surface is provided at the bottom of the groove. The stress between the floating support unit and the concave spherical surface is F. When F < F... 临界, only the first ball bead abuts against the concave spherical surface; when F>F 临界 , while the first ball bead abuts against the concave spherical surface, the groove bottom of the groove also abuts against the rounded end.

[0007] Said gap includes a first gap between the rounded end and the groove bottom, and a second gap between the conical column section and the groove; when F<F 临界 , the first gap between the bullet head and the groove exists; when F>F 临界 , the first gap between the bullet head and the groove disappears.

[0008] A rounded transition structure is provided between the concave spherical surface and the groove bottom to form an annular concave surface. The inner diameter of the concave spherical surface matches the outer diameter of the first ball bead. The upper side of the first ball bead abuts against the concave spherical surface to form a first contact surface, and the lower side abuts against the upper side of the second ball bead to form a second contact surface. The frictional force at the first contact surface is F1, and the frictional force at the second contact surface is F2. When F1<F2, sliding friction occurs at the first contact surface, and when F1>F2, sliding friction occurs at the second contact surface.

[0009] The length direction of the support tube is parallel to the axial direction of the fixed shaft.

[0010] The inner wall of the first chamber for accommodating the first ball bead in the chamber is cylindrical, the diameter of the cylinder is larger than that of the first ball bead, the first ball bead can rotate in the horizontal direction and move up and down in the first chamber, and the closing structure is arranged at the end of the first chamber; the inner wall of the second chamber for accommodating the second ball bead is cylindrical, the diameter of the cylinder is larger than that of the second ball bead, and the second ball bead can move up and down.

[0011] A partition structure is arranged between the first chamber and the second chamber, the diameter of the partition structure is smaller than the diameter of the first ball bead, and the partition structure is connected with the first chamber and the second chamber through conical surfaces.

[0012] Wear-resistant coatings are applied on the rounded end, the groove bottom, the concave spherical surface and the surface of the ball bead.

[0013] Another objective of the present invention is to provide a blood pump with low wear, stable transmission and long service life.

[0014] To achieve the above objective, the technical solution adopted by the present invention is: a blood pump, comprising a motor and an impeller, a magnet is arranged on the impeller, the magnet is arranged adjacent to the magnet in the motor, the magnet in the impeller and the magnet in the motor form a magnetic coupling transmission structure, the fixed shaft is fixed to the motor, the rotating shaft is fixed to the impeller, and the direction of power-on of the coil in the motor is changed to drive the impeller to rotate.

[0015] The above solution achieves efficient, stable, and low-wear operation of the connecting shaft through a double ball bearing structure and a special spring support design. Furthermore, by adjusting the contact force between the balls and the grooves, the primary location of wear can be controlled, thereby extending the service life of the connecting shaft. Attached Figure Description

[0016] Figure 1 This is the front view of the connecting axis; Figure 2 for Figure 1 A sectional view; Figure 3 for Figure 2 Enlarged diagram of the middle section; Figure 4 This is a schematic diagram of a fixed shaft. Figure 5 for Figure 4 A sectional view; Figure 6 This is a structural schematic diagram of a floating support unit; Figure 7 This is a schematic diagram of the cavity structure; Figure 8 This is a sectional view of the axis of rotation; Figure 9 This is a schematic diagram of a blood pump. Detailed Implementation

[0017] The following is combined Figures 1-9 The present invention will be described in further detail below.

[0018] A connecting shaft includes a fixed shaft 10 and a rotating shaft 20 that rotates around the fixed shaft 10. A floating support unit 30 is disposed within a chamber A of the fixed shaft 10. The floating support unit 30 abuts against the rotating shaft 20. The contact position between the rotating shaft 20, the fixed shaft 10, and the floating support unit 30 changes with the stress between the floating support unit 30 and the rotating shaft 20. It should be noted that the axial floating range of the floating support unit 30 is very small, approximately 0–0.5 mm, and will not affect the smoothness of the connecting shaft's movement. This invention is based on a stress and sliding friction dispersion mechanism. While ensuring smooth rotation of the rotating shaft 20 and the fixed shaft 10, the contact position between the rotating shaft 20, the fixed shaft 10, and the floating support unit 30 changes with the stress and sliding friction between the floating support unit 30 and the rotating shaft 20. This disperses wear between the rotating shaft 20 and the fixed shaft 10 to different parts, thereby improving the service life of the connecting shaft.

[0019] In a preferred embodiment of the present invention, the floating support unit 30 includes a first ball 31 and a second ball 32. The first ball 31 is disposed near the end of chamber A, and the end of chamber A is provided with a constriction structure 13. The diameter of the constriction structure 13 is smaller than the diameter of the first ball 31 to prevent the first ball 31 from jumping out of the chamber. A support tube 33 is disposed inside chamber A, and a spring piece 35 is disposed between the support tube 33 and the bottom of chamber A. The spring piece 35 is a shallow disc with an opening facing away from the support tube 33. One end of the support tube 33 abuts against the spring piece 35, and the spring piece 35 abuts against the fixed shaft 10, while the other end abuts against the second ball 32. A spring 34 is sleeved on the tube body of the support tube 33, and the spring 34 provides elastic force to drive the second ball 32 to move in the direction of the rotation shaft 20. The first ball 31 and the second ball 32 are made of high-hardness polymer material to improve wear resistance. In the initial state, the spring 34 pushes the second ball 32 towards the first ball 31, so that the first ball 31 abuts against the inner edge of the opening at the end of the chamber A towards the constriction structure 13. When the first ball 31 abuts against the concave spherical surface 22 of the rotating shaft 20, the stress overcomes the elastic force of the spring 34 and squeezes the first ball 31 towards the second ball 32. The support tube 33 is made of lightweight metal material to reduce the overall weight and improve support stability; the spring piece 35 is made of a metal material with good elasticity to ensure good deformation recovery ability when subjected to stress.

[0020] As shown in the figure, the fixed shaft 10 is bullet-shaped near the rotating shaft 20, including a conical section 11 and a rounded end 12. The end of the rotating shaft 20 has a bullet-shaped groove 21. A gap B is left between the groove 21 and the inclined surface of the conical section 11. A concave spherical surface 22 is provided at the bottom of the groove 21. The stress between the floating support unit 30 and the concave spherical surface 22 is F, and there is a critical point F between the stresses. 临界 When F < F 临界 At that time, only the first bead 31 abuts against the concave spherical surface 22; when F > F 临界 At the same time, the first ball 31 abuts against the concave spherical surface 22, and the annular concave surface also abuts against the smooth end 12. That is to say, under different stresses, the floating support unit 30 will have a small deformation in its axial direction, which changes the gap B. The concave spherical surface 22 contacts the end of the floating support unit 30, or at the same time the smooth end 12 abuts against the bottom of the groove 21, the friction part changes, thereby dispersing the wear to different positions.

[0021] Furthermore, the gap B includes a first gap B1 between the smooth end 12 and the bottom of the groove 21, and a second gap B2 between the conical section 11 and the groove 21, when F < F 临界 At that time, the first gap B1 between the bullet head and the groove 21 exists; when F > F 临界At this time, the first clearance B1 between the bullet head and the groove 21 disappears. The size of the first clearance B1 changes with the variation of the stress between the rotating shaft 20 and the first ball 31, and the first clearance B1 is at the maximum value in the initial state. When the stress increases and exceeds the critical point, the first clearance B1 disappears, and at this moment, the inner wall of the groove bottom of the groove 21 of the rotating shaft 20 abuts against both the first ball 31 and the rounded end portion 12 simultaneously. To satisfy the rotational movement, the second clearance B2 always exists. Preferably, the inner surface of the side wall of the groove 21 is configured as a tapered cylindrical cavity parallel to the outer wall of the tapered cylindrical section 11, so that the influence of the stress variation on the second clearance B2 is negligible.

[0022] Specifically, there is a rounded transition structure 23 between the concave spherical surface 22 and the bottom of the groove 21 to form an annular concave surface. The inner diameter of the concave spherical surface 22 matches the outer diameter of the first ball 31. The upper side of the first ball 31 abuts against the concave spherical surface 22 to form a first contact surface 311, and the lower side abuts against the upper side of the second ball 32 to form a second contact surface 321. The frictional force at the first contact surface 311 is F1, and the frictional force at the second contact surface 321 is F2. In the actual operation process, due to the influence of various factors, the magnitudes of F1 and F2 keep changing. When F1<F2, sliding friction occurs at the first contact surface 311, and wear is mainly generated at the interface where the concave spherical surface 22 abuts against the first ball 31; when F1>F2, sliding friction occurs at the second contact surface 321, and wear is mainly generated at the interface where the concave spherical surface 22 abuts against the first ball 31; when the stress further increases and the first clearance B1 disappears, the groove bottom of the groove 21 of the rotating shaft 20 comes into contact with the rounded end portion 12, and bears the wear together with the interface where the concave spherical surface 22 abuts against the first ball 31. The existence or non-existence of the first clearance B1 and the variation of the sliding frictional forces at the first contact surface 311 and the second contact surface 321 result in three switchable wear surfaces between the floating support unit 30 and the rotating shaft 20. When the rotating shaft 20 rotates, the concave spherical surface 22 at the deepest part of the groove 21 abuts against the first ball 31 to form the first contact surface 311 with a certain sliding frictional force F1, and the first ball 31 abuts against the second ball 32 to form the second contact surface 321 with a certain sliding frictional force F2. When F1<F2, wear is mainly generated at the first contact surface 311; when F1>F2, wear is mainly generated at the second contact surface 321; when the stress further increases and the first clearance B1 disappears, the annular concave surface of the rotating shaft 20 comes into contact with the rounded end portion 12, and bears the wear together with the interface where the concave spherical surface 22 abuts against the first ball 31.

[0023] Preferably, the length direction of the support tube 33 is parallel to the axial direction of the fixed shaft 10, which provides axial supporting force for the two balls, making the support more stable and reliable.

[0024] Furthermore, the inner wall of the first chamber A1, which accommodates the first ball 31, is cylindrical, and the diameter of the cylinder is slightly larger than that of the first ball 31. The first ball 31 can rotate horizontally and move vertically within the first chamber A1. The constriction structure 13 is located at the end of the first chamber A1, so that the contact area between the rotating shaft 20 and the fixed shaft 10 changes under different stresses. The inner wall of the second chamber A2, which accommodates the second ball 32, is cylindrical, and the diameter of the cylinder is slightly larger than that of the second ball 32. The second ball 32 can move vertically. The second ball 32 always abuts against the first ball 31, but their positions change depending on the magnitude of the stress.

[0025] To ensure the smooth rotation of the rotating shaft 20, a partition structure 14 is provided between the first chamber A1 and the second chamber A2. The diameter of the partition structure 14 is smaller than the diameter of the first ball 31, and the partition structure 14 is connected to the first chamber A1 and the second chamber A2 through a conical surface. Here, the partition structure 14 restricts the movement of the first ball 31, that is, the axial movement of the rotating shaft 20, to ensure the smooth operation of the rotating shaft 20. Especially in a blood pump, the smooth rotation of the impeller 50 can reduce mechanical damage to the blood.

[0026] The smooth end 12, the annular concave surface, the concave spherical surface 22, and the surface of the ball are all coated with a wear-resistant coating to improve wear resistance. The fixed shaft 10 is made of wear-resistant, high-strength engineering plastic or metal material, and the rotating shaft 20 is also made of wear-resistant, high-strength engineering plastic or metal material. The smooth end 12, the annular concave surface, and the concave spherical surface 22 are precision ground to improve surface finish.

[0027] This invention achieves efficient, stable, and low-wear operation of the connecting shaft through a double-ball bearing structure and a special spring support design. Furthermore, by adjusting the contact force between the balls and the grooves, the primary location of wear can be controlled, thereby extending the service life of the connecting shaft.

[0028] A blood pump includes a motor 40 and an impeller 50. A magnet is mounted on the impeller 50, adjacent to a magnet in the motor 40. The magnets in the impeller 50 and the motor 40 form a magnetic coupling transmission structure. A fixed shaft 10 is fixed to the motor 40, and a rotating shaft 20 is fixed to the impeller 50. Changing the energizing direction of the coil in the motor 40 drives the impeller 50 to rotate. By controlling the motor winding coil to generate a rotating magnetic field, the magnet in the impeller 50 interacts with the rotating magnetic field, driving the impeller to rotate. Compared to ordinary blood pumps, the motor 40, which generates a rotating electromagnetic field, simplifies the mechanical structure of the blood pump by reducing the number of moving parts, improving the compactness of the blood pump structure, and reducing the size of the blood pump; at the same time, it reduces wear because it eliminates the need for contact supports. The magnetic coupling between the motor 40 and the impeller 50 not only causes the impeller 50 to rotate, but also provides axial and radial support, thus improving the correct alignment of the impeller 50.

[0029] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Furthermore, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, and should also be regarded as the content disclosed by the present invention.

Claims

1. A connecting shaft, comprising a fixed shaft (10) and a rotating shaft (20) rotating about the fixed shaft (10), characterized in that: A floating support unit (30) is arranged in the chamber (A) of the fixed shaft (10), the floating support unit (30) abuts against the rotating shaft (20), and the contact positions of the rotating shaft (20) with the fixed shaft (10) and the floating support unit (30) change with the variation of the stress between the floating support unit (30) and the rotating shaft (20); The floating support unit (30) comprises a first ball (31) and a second ball (32), the first ball (31) is arranged adjacent to the end of the chamber (A), and the end of the chamber (A) is provided with a closing-in structure (13), the diameter of the closing-in structure (13) is smaller than the diameter of the first ball (31), a support tube (33) is arranged in the chamber (A), an elastic sheet (35) is arranged between the support tube (33) and the bottom of the chamber (A), the elastic sheet (35) is in a shallow disc shape with the opening facing away from the support tube (33), one end of the support tube (33) abuts against the elastic sheet (35), the elastic sheet (35) further abuts against the fixed shaft (10), and the other end abuts against the second ball (32), a spring (34) is sleeved on the tube body of the support tube (33), and the spring (34) provides elastic force to drive the second ball (32) to move towards the rotating shaft (20).

2. The connecting shaft according to claim 1, characterized in that: The fixed shaft (10) is bullet-shaped near the rotating shaft (20), including a conical section (11) and a rounded end (12). The end of the rotating shaft (20) has a bullet-shaped groove (21). A gap (B) is left between the groove (21) and the inclined surface of the conical section (11). A concave spherical surface (22) is provided at the bottom of the groove (21). The stress between the floating support unit (30) and the concave spherical surface (22) is F. The stress F has a critical value F during the change process. 临界 When F < F 临界 At that time, only the first bead (31) abuts against the concave spherical surface (22); when F > F 临界 At the same time, the first ball (31) abuts against the concave spherical surface (22), and the bottom of the groove (21) also abuts against the smooth end (12).

3. The connecting shaft according to claim 2, characterized in that: The gap (B) includes a first gap (B1) between the smooth end (12) and the bottom of the groove (21) and a second gap (B2) between the conical section (11) and the groove (21), when F < F 临界 At that time, the first gap (B1) between the bullet head and the groove (21) exists; when F > F 临界 At that time, the first gap (B1) between the bullet head and the groove (21) disappears.

4. The connecting shaft according to claim 2, characterized in that: A rounded transition structure (23) is provided between the concave spherical surface (22) and the bottom of the groove (21) to form an annular concave surface, the inner diameter of the concave spherical surface (22) matches the outer diameter of the first ball (31), the upper side of the first ball (31) abuts against the concave spherical surface (22) to form a first contact surface (311), the lower side abuts against the upper side of the second ball (32) to form a second contact surface (321), the friction force at the first contact surface (311) is F1, and the friction force at the second contact surface (321) is F2. When F1<F2, sliding friction occurs at the first contact surface (311), and when F1>F2, sliding friction occurs at the second contact surface (321).

5. The connecting shaft according to claim 1, characterized in that: The length direction of the support tube (33) is parallel to the axial direction of the fixed shaft (10).

6. The connecting shaft according to claim 2, characterized in that: The inner wall of the first chamber (A1) for accommodating the first ball (31) in the chamber (A) is cylindrical, the diameter of the cylinder is larger than that of the first ball (31), the first ball (31) can rotate in the horizontal direction and move up and down in the first chamber (A1), and the closing-in structure (13) is arranged at the end of the first chamber (A1); the inner wall of the second chamber (A2) for accommodating the second ball (32) is cylindrical, the diameter of the cylinder is larger than the diameter of the second ball (32), and the second ball (32) can move up and down.

7. The connecting shaft according to claim 6, characterized in that: A partition structure (14) is arranged between the first chamber (A1) and the second chamber (A2), the diameter of the partition structure (14) is smaller than the diameter of the first ball (31), and the partition structure (14) is connected with the first chamber (A1) and the second chamber (A2) through conical surfaces.

8. The connecting shaft according to claim 2, characterized in that: The rounded end (12), the groove bottom of the groove (21), the concave spherical surface (22) and the surfaces of the balls are all coated with a wear-resistant coating.

9. A blood pump comprising the connecting shaft according to any one of claims 1-8, characterized in that: The impeller (50) includes a motor (40) and an impeller (50). A magnet is provided on the impeller (50) and is arranged adjacent to the magnet in the motor (40). The magnet in the impeller (50) and the magnet in the motor (40) constitute a magnetic coupling transmission structure. The fixed shaft (10) is fixed to the motor (40), and the rotating shaft (20) is fixed to the impeller (50). The direction of the energization of the coil in the motor (40) drives the impeller (50) to rotate.

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