JPH10295807A - Magnetic attraction force adjusting device and magnet pump using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a magnet-driven rotating device such as a blood pump, the distance between magnets and the magnetic attraction force can be adjusted to the rotational speed of the magnet without requiring special measurement, calculation, control, operation, etc. Automatically adjust accordingly. SOLUTION: The rotating shaft body 130 is provided with a driven magnet 110 which is rotated by a rotary driving means at a rear end thereof, and a driving magnet 120 at a front end side thereof, and integrally rotates therewith. The rotating shaft body rotates together with the rotating shaft and supports a weight 140 that moves outward and moves to the front end side by centrifugal force as the rotation speed increases, and the drive-side magnet moves to the front end side as the weight moves to the front end side. It is connected to the weight so as to move, and a tensile force is applied to the rear end side by a spring 160.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive magnet for rotating a rotor such as an impeller of a heart-lung machine blood pump for driving a rotor from the outside of a casing. The present invention relates to a magnetic attraction device that automatically adjusts according to speed.

[0002]

2. Description of the Related Art In a blood pump for a heart-lung machine, as shown in FIG. 5, pivots 16 and 17 at both upper and lower ends of a rotating shaft 15 are accommodated in a casing 2 and a bearing 26 at a top 22 of the casing and a casing. The magnet 14 of the impeller 1 supported by the bearing 27 at the center of the bottom plate 23 and the driving magnet 31 of the driving device 3 are magnetically coupled via a casing, and the rotation of the driving magnet 31 causes the impeller 1 to rotate on its rotating shaft. Rotated around 15.

Reference numeral 32 denotes a rotary drive device for rotating the drive magnet 31 coaxially with the rotation center axis of the impeller 1;
A rotor 35 similar to the rotor of the DC brushless motor is supported on a shaft 33 via a bearing 34. 36 is a rotor winding and 37 is a stator. 1
Numeral 3 is a blade provided on the conical side surface 11 of the impeller 1 and functions as a pump by rotation of the impeller. 24 and 2
Reference numeral 5 denotes a blood inlet and a blood outlet of the casing 2.

[0004]

In such a blood pump, the impeller 1 is attracted to the bottom side of the casing 2 by the magnetic attraction between the magnet 14 on the bottom side of the impeller and the driving magnet 31 opposed to the impeller via the casing 2. When the rotational speed of the impeller is low, the impeller 1 rotates mainly supported by the pivot 17 at the lower end of the rotary shaft 15 and the bearing 27. When the rotation speed of the impeller increases, the pressure of the blood in the casing 2 becomes low on the upper side of the impeller and high on the lower side of the impeller, so that a floating force acts on the impeller 1. In a state where the floating force and the magnetic attraction force, in particular, the sum of the magnetic attraction force and the impeller weight is balanced, the impeller 1 is in a weightless state, and performs a stable ideal rotation without applying a large force to the pivot and the bearing. .

When the rotation speed of the impeller further increases and the levitation force acting on the impeller exceeds the magnetic attraction force, the impeller is supported mainly by the pivot 16 at the upper end of the rotating shaft 15 and its bearing 26. At this time, a large force is applied to the pivot 16 and the bearing 26, and together with the high rotation speed, the pivot 16 and the bearing 26 are easily damaged, and the rotation of the impeller 1 becomes unstable, causing hemolysis. There is a risk. Therefore, according to the rotation speed of the impeller 1, that is, the rotation speed of the drive magnet 31, preferably, the levitation force and the magnetic attraction force due to the rotation speed of the impeller are balanced so that the impeller-side magnet 14 and the drive magnet 31 are balanced.
It is desired to adjust the magnetic attractive force between the two.

The applicant of the present application has proposed a blood pump provided with a means for adjusting the magnetic attraction force described in Japanese Patent Application No. 8-103655. FIG. 5 described above actually shows an embodiment of the invention of the above-mentioned application.
A magnetic attraction force adjusting means 4 including a supporting table 41 for supporting the casing and a spacer 42 is interposed between the bottom surface of the driving device 3 and the driving device 3. The spacer 42 is detachably inserted between the supporting table 41 and the driving device 3 or between the supporting table 41 and the casing 2 so as to be superimposed on and detachable from the supporting table 41, and has one or more sheets having an appropriate thickness. By inserting or removing the spacer, the facing distance between the magnet 14 of the impeller 1 and the driving magnet 31 of the driving device 3 is adjusted, and the magnetic attraction between the magnets 14 and 31 is adjusted.

In the above-mentioned application, as another embodiment, although not shown, the feed screw is rotated manually or by a stepping motor, and the supporting table 41 is moved up and down by a rack and pinion system, so that the magnet 14 of the impeller is rotated.
And a means for adjusting the vertical position of the supporting table or the inclination of the supporting table with respect to the horizontal plane by rotating the eccentric cam that supports the supporting table 41. I have.

However, any of the above adjusting means requires a manual adjusting operation, and cannot immediately respond to a change in the rotation speed of the impeller. It also requires measurement and monitoring for adjustment. In the case where the feed screw is rotated by a step motor, the rotation speed of the impeller, the magnet 14
By feeding back data such as the interval between the steps 31 and 31, the flow rate of blood, etc. to the control unit of the step motor, the magnet interval, that is, the magnetic attraction force can be controlled to be optimal. It requires means and an arithmetic and control unit, and also requires operating energy.

The present invention has been made in view of the above points, and does not require manual adjustment, data collection by many sensors, and adjustment by arithmetic control thereof, and utilizes the rotation of the drive magnet itself. An object of the present invention is to provide a device for automatically adjusting a magnetic attraction force between magnets by automatically adjusting a position of a driving magnet.

[0010]

According to the present invention, there is provided a magnetic attraction adjusting device according to the present invention, wherein a driven magnet rotated by a rotary driving means is coaxially coupled to the driven magnet at a rear end. A rotating shaft that rotates integrally with the magnet, a driving magnet that is axially movably supported at the front end of the rotating shaft, and that rotates integrally with the rotating shaft; A weight supported by the rotary shaft so as to move outward by centrifugal force and move to the front end side of the rotary shaft as the speed increases, and a rear end of the rotary shaft toward the drive-side magnet. And a tension means such as a spring for applying a pulling force to the rotating shaft body so that the driving magnet moves toward the rotating shaft body front end side as the weight moves toward the rotating shaft body front end side due to the centrifugal force of the weight. Litho are coupled, the distance between the drive-side magnet and the rotor magnet to be magnetically coupled thereto, characterized in that it is automatically adjusted in accordance with the rotational speed of the drive side magnet.

As described above, in the attraction force adjusting device of the present invention, the rotating shaft that rotates coaxially and integrally with the driving magnet, and the weight that rotates about the axis of the rotating shaft are the driving side magnet. The rotational speed of the magnet, and therefore
As the rotation speed of the rotary shaft increases, the rotary shaft moves outward by centrifugal force and moves to the front end side of the rotary shaft. The drive-side magnet is connected to the weight so that the weight moves toward the rotation shaft front end, that is, in a direction approaching the rotor magnet, as the weight moves toward the rotation shaft front end,
A tensile force such as a tension spring is applied to the rear end side of the rotating shaft body, that is, in a direction away from the magnet of the rotor.

Therefore, when the drive-side magnet is stationary, the drive-side magnet is pulled toward the rear end of the drive shaft, so that the distance between the drive-side magnet and the magnet of the rotor is maximized. The magnetic attraction between the magnet and the rotor magnet is minimized. As the drive magnet rotates and its rotation speed increases, the weight moves outward due to centrifugal force and moves toward the front end of the rotating shaft, and the drive magnet also resists the pulling force of the pulling means accordingly. As a result, the rotor moves toward the front end side of the rotating shaft, and the distance between the drive-side magnet and the magnet of the rotor becomes smaller, and the magnetic attraction increases. Conversely, when the rotation speed decreases, the weight moves inward and moves toward the rear end of the rotating shaft, and accordingly, the driving magnet also rotates against the magnetic attraction of the rotor magnet. Move to the posterior end.

That is, in the magnetic attraction force adjusting device of the present invention, the rotation between the driving magnet and the rotating shaft is utilized, and the distance between the driving magnet and the rotor magnet and the magnetic field are adjusted according to the rotation speed. The suction power is adjusted automatically. When the rotor is an impeller of a pump such as a blood pump, the weight of the weight, the number of the weight, the length of the arm connecting the weight to the rotating shaft, the spring constant of the tension means spring, and the like are appropriately selected. The force can be balanced with the levitation force acting on the impeller, automatically resulting in an ideal rotation condition that results in an impeller weightless condition.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details and embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a magnetic attraction force adjusting device 100 according to an embodiment of the present invention, in which a central axis A is shown.
The left side of -A shows a state where the rotating shaft body and the like are stationary, and the right side of the central axis shows a state where the rotating shaft body and the like are rotating at high speed. The magnetic attraction adjusting device 100 is, for example, the magnetic attraction adjusting means 4 in the blood pump of FIG.
And is disposed between the casing 2 that rotatably accommodates the impeller 1 and the driving device 3, and is fitted to the casing 2 and the driving device 3, for example, by fitting or screwing. They are connected by connecting means.

In FIG. 1, reference numeral 130 denotes a rotating shaft.
The stand 150 is supported by a bearing 152 formed of a bearing. A pedestal 111 is attached to the rear end (lower end) of the rotating shaft body 130 concentrically and integrally with the rotating shaft body 130 by a mounting screw 112, and a driven magnet 110 constituted by a permanent magnet is fixedly supported on the pedestal 111. Have been. The driven magnet 110 is connected to the driving device 3 shown in FIG.
Is rotationally driven by the rotation of the drive magnet 31 rotated by a motor or the like, and the concentrically and integrally connected rotary shaft 130 is rotated about its axis.

In the middle of the rotating shaft 130, the rotating shaft 1
The other end of the arm 141 having a weight 140 extended outwardly perpendicular to the side peripheral surface of the arm 30 and rigidly connected to one end thereof is rotatable around an axis perpendicular to the axial direction of the rotating shaft body 130. The weight 140 and the arm 141 are supported by the rotary shaft 130 so that the weight 140 and the arm 141 rotate about the rotary shaft together with the rotary shaft 130. Reference numeral 142 denotes the above-mentioned connecting portion, the details of which will be described later. A plurality of weights 140 and arms 141, for example, three weights and arms are evenly arranged around the rotation shaft body 130 at an angle of 120 degrees from each other around the rotation shaft body 130.

The pedestal 121 is concentric with the shaft portion 131 via a linear bush 132 slidable along the shaft portion 131 on the shaft portion 131 having a small diameter at the front end side (upper end side) of the rotary shaft body 130. Are combined. A driving magnet 120, which is also made of a permanent magnet, is fixedly supported on the pedestal 121 concentrically with the shaft 131, and faces the magnet 14 of the impeller 1 of FIG.
4 is magnetically coupled.

The pedestal 121 is moved from its outer peripheral surface to the rotating shaft 13.
A diametrically extending arm 122 having a slider 12 slidable along the arm.
3 is attached. Although not shown in cross section, the slider 123 is provided with a bearing at a portion in contact with the arm 122 inside the cylinder so as to easily slide along the arm. The linear bush 132 has the same structure.

The slider 123 is provided with a rod 124 extending from the rear end (lower end) surface toward the rear end side in parallel with the axis of the rotary shaft 130. The rod 124 is rigidly connected to the slider 123. I have. The tip of the rod 124 is connected to the weight 140. Weight 1
As described later, the rod 40 moves outward due to the centrifugal force caused by the rotation and moves in the circular direction to move to the front end side of the rotary shaft 130, so that the rod 124 is maintained in a direction parallel to the axis of the rotary shaft. As shown in FIG. 3, the distal end of the rod 124 is supported by the shaft 125 so as to be rotatable around the axis 125 passing through the center of the weight. 126 is a bearing.

The rotary shaft 130 has a plurality of through-holes 134 extending in a direction parallel to the axis thereof and extending through the step 138 and the rear end face. The holes 134 are symmetrically formed around the axis of the rotary shaft. A helical spring 160 is housed in the through hole 134, and the helical spring 160 is fixed to the pedestal 111 having a rear end coupled to a rear end of the rotating shaft body in an extended state, A front end of a spring is fixed to a rear end side surface of the pedestal 121 which is slidably connected to a shaft portion 131 on a front end side of the rotary shaft body. Accordingly, the helical spring 160 constantly applies a pulling force to the pedestal 121 in a direction toward the rear end of the rotary shaft 130. Reference numeral 153 in the figure is a cover case which is connected to the stand 150 by screws 154.

Arm 141 having weight 140 at one end
FIG. 2 shows an example of a connecting portion 142 between the shaft member 130 and the rotating shaft body 130. FIG. 2 is an explanatory view of the connecting portion, and shows the rotating shaft body 130.
FIG. 6 shows a cross-sectional view of the coupling portion 142 cut perpendicularly to the axis of FIG. A support 135 attached to the outer peripheral surface of the rotary shaft 130 by appropriate means has two parallel plates 13 parallel to arms extending outwardly perpendicular to the side peripheral surface of the rotary shaft.
6,136 are erected. And the plate 13
6,136 through a bolt shaft 143 vertically penetrating and supported rotatably on the plate via bearings 137.
The distal end of the arm 141 is rigidly connected.

Accordingly, the arm 141 is rotatable about the horizontal shaft 143, but the downward rotation is limited by a suitable stopper (not shown) so that the weight does not contact the floor 151 of the stand 150. Is done. Fig. 14
Reference numeral 4 denotes a nut screwed with the bolt shaft 143. In addition, the rotating shaft 1 of the support 135 and the parallel plate 136 is used.
In order to facilitate attachment to the 30, the outer peripheral surface of the rotating shaft body may be cut at these attachment portions, and the outer peripheral surface may be formed into a regular triangle or a regular polygon.

In the magnetic attraction force adjusting device according to the present invention configured as described above in detail, when the driven magnet 110 is not driven to rotate by the driving magnet of the driving device and is stationary, FIG. Axis AA of
The weight 140 is stationary at a position close to the floor 151 of the stand 150 due to its gravity. At this time, the driving magnet 120 is located closest to the rear end, and the magnet 14 of the impeller 1 in FIG.
Is the largest, and the magnetic attraction between the driving magnet 120 and the magnet 14 is the smallest.

When the driven magnet is driven to rotate, the rotary shaft 130 integrated therewith rotates, and the drive magnet 120 also rotates integrally with the rotary shaft 130. When the rotation speed increases, the weight floats toward the front end side of the rotary shaft body due to centrifugal force, and the arm 141 rotates around the shaft 143, and the weight 140 makes a circular motion and the diameter of the rotary shaft body. In the direction of movement and to the front end of the rotating shaft. Due to the movement of the weight 140, the rod 124 connected to the weight pushes up the slider 123 to the front end side of the rotating shaft and moves the slider 123 to the outside in the diameter direction of the rotating shaft, so that the arm 122, the pedestal 121 and the driving magnet 120 are suspended. The coil spring 160 is moved to the front end side against the tensile force.

The pedestal 121 and the driving magnet 12
The movement of the arm 141 to the front end side of the rotating shaft body increases as the rotating speed of the integral rotation of the driven magnet, the rotating shaft body and the driving magnet increases, and the rotating speed further increases.
When the weight 140 rises until is almost level, the pedestal 1
21 contacts the stopper 133 at the front end of the shaft portion 131 of the rotary shaft body, and further movement is suppressed. Conversely, when the rotation speed decreases, the centrifugal force acting on the weight 140 decreases, and the weight descends to the rear end side. Pulled down. At this time, the pulling force of the helical spring 160 is applied to the drive side magnet and the impeller 1.
In this case, the driving magnet 120 and the pedestal 121 can be pulled down toward the rear end side against the magnetic attraction force acting between the magnet 14 (FIG. 5).

As described above, the driving magnet 120 moves toward the front end or the rear end of the rotating shaft in accordance with the rotational speed of the integral rotation of the rotating shaft and the driving magnet. Is adjusted. The distance between the driving magnet 120 and the magnet 14 of the impeller of FIG. 5 which is magnetically coupled to the driving magnet 120 and the magnetic attraction force are adjusted according to the rotation speed of the driving magnet. FIG. 4 shows an experimental example of the relationship between the distance between the two magnets and the rotation speed (rpm). In a region where the distance between the two magnets increases and decreases with the rotation speed, the distance between the two magnets is changed by the rotation. It corresponds to the speed (rpm) on a one-to-one basis, and the distance between the two magnets decreases as the rotation speed increases. That is, it is automatically adjusted so that the rotational speed of both magnets increases and the magnetic attraction between both magnets increases.

In the above-described embodiment, the magnetic attraction force adjusting device formed separately from the driving device 3 is shown. However, the magnetic attraction force adjusting device according to the present invention includes, for example, , And can be configured integrally with the driving device. Also,
The driven-side magnet and the drive-side magnet may be formed by electromagnets instead of being constituted by permanent magnets. In that case, the magnetic coupling or the magnetic attraction referred to in this specification means the electromagnetic coupling or the electromagnetic coupling.

[0028]

According to the magnetic attraction force adjusting device of the present invention, there is no need for special measurement, calculation, control and operation for adjusting the distance between the magnets and the magnetic attraction force between the magnets. The distance between the magnets and the magnetic attraction between the magnets are automatically adjusted according to the speed. Therefore, the magnetic attraction force adjusting device according to the present invention can be very advantageously applied to a magnet driven pump such as a blood pump.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory view of a connecting portion between an arm 142 and a rotating shaft 130, and shows a cross-sectional view of the connecting portion.

FIG. 3 is an explanatory view of a connecting portion between a weight 140 and a rod 124.

FIG. 4 is a characteristic diagram showing a relationship between a rotation speed of a magnet and a distance between the magnets in the magnetic attraction force adjusting device according to the present invention.

FIG. 5 is a longitudinal sectional view of a blood pump provided with a conventional magnetic attraction adjusting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 2 Casing 3 Drive device 14 Magnet 31 Drive magnet 110 Vertical movement magnet 120 Drive magnet 130 Rotating shaft 140 Weight 122, 142 Arm 160 A helical spring

Claims (2)

[Claims] A driven magnet rotated by a rotation driving means; a rotating shaft body coaxially coupled to the driven magnet at a rear end side and rotating integrally with the magnet; a front end of the rotating shaft body. A drive-side magnet that is supported movably in the axial direction on the side and that rotates integrally, and that rotates together with the rotary shaft body, moves outward by centrifugal force as the rotation speed increases, and moves toward the front end of the rotary shaft body. And a tension means such as a spring for applying a pulling force toward the rear end side of the rotary shaft to the drive-side magnet, the weight being supported by the rotary shaft so that the drive-side magnet moves. Is connected to the weight so as to move to the front end of the rotary shaft in accordance with the movement of the weight to the front end of the rotary shaft due to centrifugal force. A magnetic attraction force adjusting device, wherein the distance between the magnet and the magnet is automatically adjusted according to the rotation speed of the driving magnet. 2. The magnet pump according to claim 1, wherein the rotor is an impeller of a rotary pump, and is rotatably housed in a casing having an inlet and an outlet.