JP5824869B2 - pump - Google Patents

Description

  The present invention relates to a pump.

  Conventionally, an artificial heart pump has been used as an alternative heart or auxiliary heart for medical use. As an artificial heart pump, a pulsation pump and a non-pulsation pump are known. The pulsation pump is a pump that pumps blood intermittently by pulsation like an actual heart. On the other hand, a pulsation pump is a pump that continuously pumps blood without pulsating like an actual heart. Centrifugal and axial flow pumps are known as non-pulsating pumps.

  Conventionally, pulsation pumps close to the actual heart have been regarded as important, but in recent years it has been found that even non-pulsation pumps have no effect on the human body, from the viewpoint of miniaturization, weight reduction, etc. Non-pulsating pumps have attracted attention.

  The following Patent Document 1 includes a pump housing 2 having a suction port 6 for sucking blood and a discharge port 7 for discharging blood, and an impeller 100 having a blade 8 and provided in the pump housing 2. A spiral pump 1 (artificial heart pump) is described (paragraph [0072], FIG. 1 and FIG. 2). The centrifugal pump 1 is a centrifugal non-pulsating pump. The pump housing 2 is provided with coils 15 and 16, and the blade 8 of the impeller 100 is provided with a permanent magnet 14 (paragraph [0096]). The impeller 100 rotates due to the interaction between the magnetic field excited by the coils 15 and 16 and the permanent magnet 14.

  Here, since the impeller 100 is a member that directly contacts blood, it is covered with a biocompatible titanium nitride film or the like (paragraphs [0097] to [0101]). This coating is applied to the impeller 100 by physical vapor deposition or the like.

  As described in Patent Document 1, when a coating of a biocompatible material is formed on an impeller, a treatment at a high temperature is generally required. For example, in the case of titanium nitride film formation by physical vapor deposition, the impeller is exposed to high temperatures.

  Here, in the technique of Patent Document 1, since the permanent magnet is disposed on the blade of the impeller, there are the following problems.

Special Table 2002-541986

When the impeller is exposed to a high temperature as described above, the permanent magnet is also exposed to a high temperature when the coating is formed, and the permanent magnet is demagnetized.
It is not limited to the case where the coating is formed on a permanent magnet, that is, not only when the pump is applied as an artificial heart pump, but because the permanent magnet is exposed to the fluid to be transported, the permanent magnet may deteriorate depending on the type of fluid. As a result, the performance of the pump decreases.
On the other hand, for example, when the coil is attached to the impeller, the fluid may be adversely affected by the heat generated by the coil during operation of the pump.

  In view of the circumstances as described above, an object of the present invention is to realize a pump that can suppress the deterioration of the permanent magnet and maintain the expected performance of the pump, and further to the fluid due to heat generation of the coil. It is in providing the pump which can suppress an adverse effect.

In order to achieve the above object, a pump according to an embodiment of the present invention includes a housing, an impeller, and a stator.
The housing has a pump chamber and a stator chamber provided independently of the pump chamber.
The impeller has a plurality of rotor teeth arranged at a first pitch along the circumferential direction of rotation, and pumps fluid by rotation.
The stator includes a plurality of stator teeth, a coil, and a permanent magnet, and is disposed to face the impeller in the axial direction of the rotation.
The plurality of stator teeth each include a facing surface facing the rotor teeth, and are arranged at a second pitch different from the first pitch along the circumferential direction.
The coils are coils wound around the respective stator teeth, and electric power having different phases is supplied to the coils adjacent to each other in the direction along the circumferential direction.
The permanent magnets are provided on the facing surfaces of the stator teeth, and are arranged so that the magnetic poles are alternately different along the circumferential direction.
The impeller is provided in the pump chamber and pumps fluid in the pump chamber.
The stator is provided in the stator chamber.

  In the present invention, a stator having a plurality of stator teeth around which coils are wound is provided in the stator chamber of the housing, and when electric power is supplied to the coils, magnetic flux is generated in the stator teeth. The coils that are adjacent to each other in the direction along the circumferential direction of the rotation are supplied with electric power having different phases, so that magnetic fluxes having different strengths are generated in principle on the adjacent stator teeth. Will change.

  The magnetic flux generated in the stator teeth by the coils is applied to the permanent magnets that are provided on the opposing surfaces of the stator teeth and arranged so that the magnetic poles are alternately different along the circumferential direction. Strengthen or weaken the magnetic flux.

  Thereby, the magnetic flux from which strength changes temporally in the direction along the circumferential direction is generated from the stator side. The magnetic flux generated from the stator side acts on the rotor teeth of the impeller that is rotatably provided in the pump chamber of the housing. Thereby, the rotor teeth arranged at a pitch (second pitch) different from the pitch of the stator teeth (first pitch) are guided to rotate the impeller. By the rotation of the impeller, the fluid in the pump chamber is pumped.

Thus, in this invention, the operation | movement of a pump is implement | achieved, without arrange | positioning a permanent magnet to an impeller. Thereby, since a permanent magnet is not exposed to a fluid, deterioration of a permanent magnet can be suppressed and the expected performance of a pump can be maintained.
In addition, not only the permanent magnet but also the coil is not arranged on the impeller side, that is, because it is mounted on the stator disposed in the stator chamber provided independently of the pump chamber, the adverse effect on the fluid due to the heat generated by the coil Can be suppressed.

In the pump, the rotor tooth may be a rotor blade having a function as a blade for pumping the fluid by rotation.
In the present invention, since the rotor blade combines the function as the rotor tooth and the function as the blade, it is not necessary to provide a blade on the impeller in addition to the rotor tooth. Thereby, a pump can be reduced in size and thickness.

  As described above, according to the present invention, it is possible to suppress the deterioration of the permanent magnet and maintain the expected performance of the pump. In addition, adverse effects on the fluid due to the heat generated by the coil can be suppressed.

It is sectional drawing which shows the artificial heart pump which concerns on one Embodiment of this invention. It is a perspective view which shows an artificial heart pump, and is a figure which shows the state by which some artificial heart pumps were fractured | ruptured. It is the perspective view which looked at the impeller which concerns on one Embodiment of this invention from the stator side. It is the front view which looked at the impeller which concerns on one Embodiment of this invention from the stator side. It is a rear view of the impeller which concerns on one Embodiment of this invention. It is a side view of the impeller which concerns on one Embodiment of this invention. It is side sectional drawing of the impeller which concerns on one Embodiment of this invention. It is the perspective view which looked at the stator which concerns on one Embodiment of this invention from the impeller side, and is a figure which shows a mode that a part of stator was decomposed | disassembled. It is the front view which looked at the stator which concerns on one Embodiment of this invention from the impeller side. It is a figure for demonstrating the operating principle of an artificial heart pump, and is a figure which shows a mode that the impeller and the stator were expand | deployed linearly. It is a figure for demonstrating the operating principle of an artificial heart pump, and is a figure which shows the change of the electric current which flows into the coil of U phase, V phase, and W phase. It is the perspective view which looked at the impeller which concerns on other embodiment from the stator side. It is the front view which looked at the impeller which concerns on other embodiment from the stator side. It is a side view of the impeller which concerns on other embodiment. It is a perspective view which shows the impeller which concerns on another embodiment. It is a side view which shows the impeller which concerns on another embodiment. It is side sectional drawing which shows the artificial heart pump which concerns on another embodiment. It is the perspective view which looked at the impeller which concerns on another embodiment from the stator side. It is the perspective view which looked at the impeller which concerns on another embodiment from the back side.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
[Overall configuration of artificial heart pump]
FIG. 1 is a sectional view showing an artificial heart pump as a pump according to the first embodiment of the present invention. FIG. 2 is a perspective view showing an artificial heart pump, and shows a state in which a part of the artificial heart pump is broken.

  As shown in these drawings, the artificial heart pump 100 includes a housing 3 having a pump housing 31 in which a pump chamber 311 is formed and a stator housing 32 in which a stator chamber 321 is formed. Further, the artificial heart pump 100 is provided in the pump chamber 311 so as to be rotatable about the shaft portion 31D as a central axis, and in the impeller 1 that pumps blood (fluid) in the pump chamber 311 by rotation, and in the stator chamber 321, A stator 2 is provided which is arranged corresponding to the impeller 1 in the axial direction of rotation of the impeller 1 and generates a magnetic field for rotating the impeller 1.

In the description of the present specification, the direction in which the axis of rotation of the impeller 1 faces (z-axis direction) is an axial direction, the direction around the rotation is a circumferential direction, and the radial direction of the rotation is a radial direction.
In the description of the present specification, the side where the impeller 1 faces the stator 2 will be described as the front side of the impeller 1, and the opposite side will be described as the back side of the impeller 1. Further, the side where the stator 2 faces the impeller 1 will be described as the front side of the stator 2, and the opposite side will be described as the back side of the stator 2.

[Structure of housing]
The pump housing 31 has a cylindrical shape as a whole, and has a size that allows the impeller 1 to be rotatably accommodated in the pump chamber 311.
The pump housing 31 includes a cylindrical tube portion 31A, a disk-shaped first side wall portion 31B disposed on the front side of the impeller 1, and a disk-shaped second side wall portion disposed on the back side of the impeller. And 31C.

The pump housing 31 is provided with an inflow pipe 4 through which blood flows into the pump chamber 311 and an outflow pipe 5 through which blood flows out of the pump chamber.
One end portion of the inflow pipe 4 is connected to the center of the first side wall portion 31B of the pump housing 31, and is provided so as to extend from the pump housing 31 in the axial direction. The inflow pipe 4 is provided so as to communicate with the center of the stator housing 32.

  On the other hand, the outflow pipe 5 has one end connected to the cylindrical portion 31 </ b> A of the pump housing 31, and is provided so as to extend from the pump housing 31 in the radial direction (centrifugal direction).

  A shaft portion 31 </ b> D is provided inside the pump housing 31. The shaft portion 31D has a cylindrical shape and is provided so as to extend from the center of the second side wall portion 31C of the pump housing 31 toward the inside of the pump chamber 311 in the z-axis direction. The shaft portion 31D is set so that the outer diameter is slightly smaller than the inner diameter of the ring-shaped impeller 1 (see FIG. 3), and the outer peripheral surface of the shaft portion 31D is the inner periphery of the impeller 1. Opposed to the surface with a gap.

  A radial dynamic pressure groove (not shown) that generates dynamic pressure in the radial direction when the impeller 1 rotates is formed on the outer peripheral surface of the shaft portion 31D. Due to the dynamic pressure generated by the radial dynamic pressure grooves, the impeller 1 can rotate around the shaft portion 31D as a central axis without contacting the shaft portion 31D during rotation. The radial dynamic pressure groove may be provided on the inner peripheral surface side of the impeller 1.

The stator housing 32 has a cylindrical shape like the pump housing 31 and has a size that allows the stator 2 to be accommodated in the stator chamber 321.
The stator housing 32 includes a cylindrical portion 32A, a disk-shaped first side wall portion 32B disposed on the front side of the stator, and a disk-shaped second side wall portion 32C disposed on the stator back side. .
In the center of the first side wall portion 32B and the second side wall portion 32C of the stator housing, openings for communicating the inflow pipe 4 are provided.

  The pump housing 31, the stator housing 32, the inflow pipe 4 and the outflow pipe 5 are made of a biocompatible material. Examples of the biocompatible material include polymers such as pure titanium, titanium alloy, titanium nitride, polyurethane, and polyester.

[Impeller configuration]
FIG. 3 is a perspective view of the impeller 1 viewed from the stator 2 side. FIG. 4 is a front view of the impeller 1 as seen from the stator 2 side, and FIG. 5 is a rear view of the impeller 1. FIG. 6 is a side view of the impeller 1, and FIG. 7 is a side sectional view of the impeller 1.

  As shown in these drawings, the impeller 1 has a ring shape. The impeller 1 is a semi-open impeller 1 and includes an impeller body 11 and a plurality of rotor blades 12 provided so as to protrude from the impeller body 11 toward the stator 2 side.

  The rotor blade 12 has both a function as a rotor tooth and a function as a blade. That is, the rotor blade 12 functions as a rotor tooth that is guided in the circumferential direction by a magnetic field generated from the stator 2 side and applies a rotational force to the impeller 1, and serves as a blade that pumps blood by generating a pressure difference by rotation. Combined with function.

  Eight rotor blades 12 are arranged at a 45-degree pitch (first pitch) along the circumferential direction of rotation (see FIG. 4). The eight rotor blades 12 are formed radially from the center of the impeller 1.

The rotor blade 12 is formed on the front side of the impeller 1 by eight blade grooves 13 formed on the front side of the impeller 1.
The blade groove 13 is formed such that the depth is not constant in the circumferential direction and the radial direction, and the depth varies in the circumferential direction and the radial direction. The blade groove 13 will be described in more detail. The blade groove 13 is formed to be curved so that the depth in the circumferential direction gradually becomes deeper in the direction opposite to the rotation direction of the impeller 1. Further, the blade groove 13 is formed to be inclined so that the depth gradually increases from the inner peripheral side to the outer peripheral side of the impeller 1 (see FIG. 7).

  The area of the blood flow path formed by the blade grooves 13 thus formed gradually increases from the inner peripheral side to the outer peripheral side of the impeller 1. Thereby, the pressure of the inner peripheral side of the impeller 1 can be effectively made higher than the pressure of the outer peripheral side of the impeller 1 by the diffuser effect during one rotation of the impeller.

  A first thrust dynamic pressure groove 14 that generates dynamic pressure in the axial direction is provided on the front surface of the rotor blade 12 (see FIGS. 3 and 4). The first thrust dynamic pressure groove 14 is provided along the edge on the rotational direction side in front of the rotor blade 12. Further, a second thrust dynamic pressure groove 15 that generates dynamic pressure in the axial direction is also provided on the back side of the impeller body 11 (see FIG. 5). It is possible to prevent the front surface of the rotor blade 12 and the inner wall surface of the first side wall portion 31B of the pump housing 31 from coming into contact with each other during one rotation of the impeller by the dynamic pressure generated by the first thrust dynamic pressure groove 14. it can. Further, the dynamic pressure generated by the second thrust dynamic pressure groove 15 prevents the back surface of the impeller 1 from contacting the inner wall surface of the second side wall portion 31C of the pump housing 31 during one rotation of the impeller. Can do.

  In FIGS. 3, 4 and 5, an example of the shape of the thrust dynamic pressure grooves 14, 15 is shown. However, the shape of the thrust dynamic pressure grooves 14 and 15 is not limited to the illustrated shape. The shape of the thrust dynamic pressure grooves 14 and 15 may be any shape as long as it can generate a dynamic pressure.

  The impeller 1 is made of a ferromagnetic material such as iron or silicon steel, and has a laminated structure in which thin ferromagnetic plates are laminated in the radial direction. Since the impeller 1 has a laminated structure in which thin ferromagnetic plates are laminated in the radial direction, generation of eddy current due to a change in magnetic field generated from the stator 2 side can be suppressed. Thereby, energy loss can be reduced.

A film (not shown) made of a biocompatible material is provided on the entire surface of the impeller 1. Thereby, it is possible to prevent a part of the impeller 1 made of a ferromagnetic material from being dissolved in the blood and causing a thrombus or the like in the blood.
Examples of the biocompatible material used for the coating include polymers such as pure titanium, titanium alloy, titanium nitride, polyurethane, and polyester.

Next, a method for manufacturing the impeller 1 will be briefly described.
First, a ring-shaped laminated structure (rolled iron core) configured by laminating thin sheets of ferromagnetic material (iron, silicon steel, etc.) in the radial direction is prepared. A plurality of blade grooves 13 are formed on one surface of the ring-shaped laminated structure. The blade groove 13 is formed to be curved so that the depth gradually increases in the circumferential direction, and in the radial direction, the blade groove 13 is inclined so that the depth gradually increases from the inner peripheral side to the outer peripheral side. Formed. The formation of the blade groove 13 forms the rotor blade 12.

  Next, a first thrust dynamic pressure groove 14 and a second thrust dynamic pressure groove 15 are formed on the front surface of the rotor blade 12 and the back surface of the impeller 1, respectively. Next, a film made of a biocompatible material (pure titanium, titanium alloy, titanium nitride, polyurethane, polyester, etc.) is formed on the entire surface of the impeller 1. For the formation of the film, a PVD (physical vapor deposition) method such as a vacuum deposition method or a sputtering method, a CVD (chemical vapor deposition) method such as a thermal CVD method, or the like can be used.

  When the coating is formed to be thick to some extent, the thrust dynamic pressure grooves 14 and 15 may be formed in the coating after the coating is formed.

Here, when a film is formed on the impeller 1 by a PVD method, a CVD method, or the like, the impeller 1 is exposed to a high temperature. For example, when a titanium nitride film is formed on the impeller 1 by a vacuum deposition method, the impeller 1 is generally exposed to a high temperature of 500 degrees or more.
Here, if a permanent magnet is disposed on the impeller 1, the permanent magnet is exposed to a high temperature and demagnetized. In addition, if the coating process is performed at a low temperature so that the permanent magnet is not demagnetized, the process takes a long time or the process becomes complicated.

  On the other hand, the permanent magnet is not arrange | positioned at the impeller 1 which concerns on this embodiment. Therefore, even if the impeller 1 is exposed to a high temperature, the permanent magnet is not demagnetized, and the coating process on the impeller 1 can be easily performed.

[Structure of stator]
FIG. 8 is a perspective view of the stator 2 as viewed from the impeller 1 side, and shows a state in which a part of the stator 2 is disassembled. FIG. 9 is a front view of the stator 2 as viewed from the impeller 1 side.

  As shown in these drawings, the stator 2 has a ring-shaped stator core 21 having a stator body 211 and a plurality of stator teeth 212 provided so as to protrude from the stator body 211 toward the impeller 1. The stator 2 includes coils 22 wound around the stator teeth 212 and permanent magnets 23 provided on the front surfaces of the stator teeth 212, respectively.

  A plurality of stator teeth 212 of the stator core 21 are provided along the circumferential direction at a pitch (second pitch) different from the pitch of the rotor blades 12. In the present embodiment, six stator teeth are provided at a pitch of 60 degrees (see FIG. 9). The stator teeth 212 are formed so that the width in the circumferential direction gradually increases from the inner peripheral side to the outer peripheral side of the stator 2.

Like the impeller 1, the stator core 21 is made of a ferromagnetic material such as iron or silicon steel, and has a laminated structure in which thin ferromagnetic plates are laminated in the radial direction. Since the stator core 21 has such a laminated structure, generation of eddy current due to a change in magnetic flux can be suppressed, and energy loss can be reduced.
The stator core 21 is formed by forming a plurality of grooves on one surface of a ring-shaped laminated structure (winding core) formed by laminating thin sheets of ferromagnetic material (iron, silicon steel, etc.) in the radial direction. Can be manufactured.

  The coils 22 wound around the stator teeth 212 are supplied with three-phase AC power of U phase, V phase, and W phase in order along the circumferential direction. That is, the AC power having different phases is supplied to the coils 22 adjacent to each other in the circumferential direction.

  The permanent magnets 23 are arranged so that the magnetic poles face the impeller 1 side, and the magnetic poles are alternately different along the circumferential direction. For one stator tooth 212, an N-pole permanent magnet 23N whose N pole faces the impeller 1 side and an S-pole permanent magnet 23S whose S pole faces the impeller 1 side are arranged. That is, two permanent magnets 23 are provided for each stator tooth 212. In the following description, the permanent magnets 23N and 23S provided for one stator tooth may be referred to as a pair of permanent magnets 23N and 23S.

  The pair of permanent magnets 23N and 23S, like the stator teeth 212, are formed so that the width in the circumferential direction increases from the inner peripheral side toward the outer peripheral side. The pair of permanent magnets 23N and 23S has the same area as the front surface 212a of the stator tooth 212, and is provided so as to cover the entire surface of the stator tooth front surface 212a.

  The permanent magnets 23 are individually separated, and the individually separated permanent magnets 23 are bonded to the front surface 212a of the stator tooth 212 with an adhesive or the like.

[Description of operation]
Next, the operation of the artificial heart pump 100 will be described.
First, the operation principle of the artificial heart pump 100 will be described.
10 and 11 are diagrams for explaining the operation principle of the artificial heart pump 100. FIG.
FIGS. 10A to 10C show a state in which the impeller 1 and the stator 2 are linearly expanded, and the currents flowing through the U-phase, V-phase, and W-phase coils 22 are maximum, respectively. The flow of magnetic flux is shown.
FIG. 11 shows changes in the current flowing through the U-phase, V-phase, and W-phase coils 22.

10 and 11, for convenience, coils supplied with U-phase, V-phase, and W-phase AC power are respectively referred to as U-phase, V-phase, and W-phase coils 22U, 22V, and 22W. Call.
The stator teeth around which the U-phase, V-phase, and W-phase coils are wound are referred to as U-phase, V-phase, and W-phase stator teeth 212U, 212V, and 212W.
Similarly, the permanent magnets provided on the U-phase, V-phase, and W-phase stator teeth 212U, 212V, and 212W are arranged as U-phase N-pole, U-phase S-pole, V-phase N-pole, V-phase S-pole, and W-phase N-pole. , W-phase S-pole permanent magnets 23UN, 23US, 23VN, 23VS, 23WN, 23WS.

  In FIG. 10, in order to distinguish the rotor blades 12, for convenience, four reference numerals 12 </ b> A to 12 </ b> D are attached in order from the left.

  First, the positional relationship between the stator tooth 212 and the rotor blade 12 at the moment when the current flowing through the U-phase coil 22U is maximum will be described with reference to FIG.

  In this case, the current flowing through the U-phase coil 22U is the maximum, and half of the current flowing through the U-phase coil 22U flows through the U-phase coil 22U through the V-phase and W-phase coils 22V and 22W. It flows in the direction opposite to the current (see FIG. 11A). As a result, magnetic fluxes are generated downward on the U-phase stator teeth 212U, upward on the V-phase stator teeth 212V, and upward on the W-phase stator teeth 212W. In this case, the magnetic flux generated in the U-phase stator teeth 212U is maximized, and half the magnetic flux generated in the U-phase stator teeth 212U is generated in the V-phase stator teeth 212V and the W-phase stator teeth 212W. .

  Focusing on the U phase, the magnetic flux generated by the U phase stator teeth 212U by the U phase coil 22U strengthens the magnetic flux of the U phase N pole permanent magnet 23UN and weakens the magnetic flux of the U phase S pole permanent magnet 23US. Focusing on the V-phase, the magnetic flux generated by the V-phase stator teeth 212V by the V-phase coil 22V weakens the magnetic flux of the V-phase N-pole permanent magnet 23VN and strengthens the magnetic flux of the V-phase S-pole permanent magnet 23VS. Focusing on the W phase, the magnetic flux generated by the W-phase stator teeth 212W by the W-phase coil 22W weakens the magnetic flux of the W-phase N-pole permanent magnet 23WN and strengthens the W-phase S-pole permanent magnet 23WS.

  As a result, the magnetic flux flows as shown in FIG. Describing the flow of magnetic flux starting from the U phase, the magnetic flux generated in the U phase stator teeth 212U by the U phase coil 22U strengthens the magnetic flux of the U phase N pole permanent magnet 23UN, and this U phase N pole It flows into the rotor blade 12A through the permanent magnet 23UN. The magnetic flux flowing into the impeller 1 side branches, and one of the branched magnetic fluxes flows into the V-phase S-pole permanent magnet 23VS via the rotor blade 12C. The other branched magnetic flux flows into the W-phase S-pole permanent magnet 23WS via the rotor blade 12D.

  The magnetic flux flowing into the V-phase stator teeth 212V is strengthened by the V-phase coil 22V, and the magnetic flux flowing into the W-phase stator teeth 212W is strengthened by the W-phase coil 22W. These magnetic fluxes merge, and the merged magnetic flux flows into the U-phase stator teeth 212U. The magnetic flux flowing into the U-phase stator teeth 212U is strengthened by the U-phase coil 22U and flows again into the rotor blade 12A via the U-phase N-pole permanent magnet 23UN.

  Since the magnetic flux flowing from the U-phase N-pole permanent magnet 23UN into the rotor blade 12A flows perpendicularly to the center of the rotor blade 12A, the force by this magnetic flux is balanced in the rotation direction of the impeller 1. The force caused by the magnetic flux flowing from the rotor blade 12C to the V-phase S-pole permanent magnet 23VS and the force caused by the magnetic flux flowing from the rotor blade 12D to the W-phase S-pole permanent magnet 23WS are opposite to the rotation direction of the impeller 1, and Since they are of similar magnitude, these forces cancel out.

  That is, at the moment when the current flowing through the U phase is maximum, the positional relationship between the stator teeth 212 and the rotor blade 12 is balanced by the positional relationship shown in FIG.

  From this state, as time elapses and the current flowing through the U-phase, V-phase, and W-phase coils 22U, 22V, and 22W changes, the U-phase, V-phase, and W-phase stator teeth 212U, 212V, and 212W The generated magnetic flux changes. Along with this, the permanent magnet 23 whose magnetic flux is strengthened and the permanent magnet 23 whose magnetic flux is weakened change, and the magnetic flux generated from the stator 2 side also changes. As the magnetic flux changes, the rotor blades 12 arranged at a different pitch from the stator teeth 212 are guided, and the impeller 1 is rotated.

  With reference to FIG. 10B, a case will be described in which time elapses from the moment when the current flowing in the U phase is maximum and the current flowing in the V phase becomes maximum.

  In this case, the current flowing through the V-phase coil 22V is the maximum, and half of the current flowing through the V-phase coil 22V is opposite to the V-phase coil 22V in the U-phase and W-phase coils 22U and 22W. It flows in the direction (see FIG. 11B). As a result, a magnetic flux is generated downward in the V-phase stator teeth 212V, and half of the magnetic flux generated in the V-phase stator teeth 212V is generated in the U-phase stator teeth 212U and the W-phase stator teeth 212W. To do.

  The flow of magnetic flux shown in FIG. 10B will be described starting from the V phase. The magnetic flux generated in the V-phase stator teeth 212V by the V-phase coil 22V increases the magnetic flux of the V-phase N-pole permanent magnet 23VN and flows into the rotor blade 12B via the V-phase N-pole permanent magnet 23VN. The magnetic flux flowing into the impeller 1 side is branched, and one of the branched magnetic fluxes flows into the U-phase S-pole permanent magnet 23US via the rotor blade 12A. The other branched magnetic flux flows into the W-phase S-pole permanent magnet 23WS via the rotor blade 12D.

  The magnetic flux flowing into the U-phase stator teeth 212U and the magnetic flux flowing into the W-phase stator teeth 212W are strengthened by the U-phase coil 22U and the W-phase coil 22W. These magnetic fluxes merge and flow into the V-phase stator teeth 212V, are strengthened by the V-phase coil 22V, and flow into the rotor blade 12B again via the V-phase N-pole permanent magnet 23VN.

  The force caused by the magnetic flux flowing into the rotor blade 12B from the V-phase N-pole permanent magnet 23VN is balanced in the rotation direction of the impeller 1. The force caused by the magnetic flux flowing from the rotor blade 12A to the U-phase S-pole permanent magnet 23US and the force caused by the magnetic flux flowing from the rotor blade 12D to the W-phase S-pole permanent magnet 23WS are opposite to the rotation direction of the impeller 1, and Since they are of similar magnitude, these forces cancel out. That is, when the current flowing in the V phase is the maximum, the positional relationship between the stator tooth 212 and the rotor blade 12 is balanced by the positional relationship shown in FIG.

  As time elapses from this state and the current flowing through the U-phase, V-phase, and W-phase coils 22U, 22V, and 22W changes, the magnetic flux generated from the stator 2 changes, thereby inducing the rotor blades. The impeller 1 is rotated.

  With reference to FIG. 10C, a case will be described in which time elapses from the moment when the current flowing in the V phase is maximum and the current flowing in the W phase becomes maximum.

  In this case, the current flowing through the W-phase coil 22W is the maximum, and the U-phase and V-phase coils 22U and 22V have half the current flowing through the W-phase coil 22W opposite to the W-phase coil 22W. It flows in the direction (see FIG. 11C). As a result, a magnetic flux is generated downward in the W-phase stator teeth 212W, and half of the magnetic flux generated in the W-phase stator teeth 212W is generated upward in the U-phase stator teeth 212U and the V-phase stator teeth 212V. To do.

  The flow of magnetic flux shown in FIG. 10C will be described starting from the W phase. The magnetic flux generated in the W-phase stator teeth 212W by the W-phase coil 22W increases the magnetic flux of the W-phase N-pole permanent magnet 23WN and flows into the rotor blade 12C via the W-phase N-pole permanent magnet 23WN. The magnetic flux flowing into the impeller 1 side is branched, and one of the branched magnetic fluxes flows into the U-phase S-pole permanent magnet 23US via the rotor blade 12A. The other branched magnetic flux flows into the V-phase S-pole permanent magnet 23VS via the rotor blade 12B.

  The magnetic flux flowing into the U-phase stator teeth 212U and the magnetic flux flowing into the V-phase stator teeth 212V are strengthened by the U-phase coil 22U and the V-phase coil 22V. These magnetic fluxes merge and flow into the W-phase stator teeth 212W.

  The force generated by the magnetic flux flowing from the W-phase N-pole permanent magnet 23WN into the rotor blade 12C is balanced in the rotational direction of the impeller 1. The force caused by the magnetic flux flowing from the rotor blade 12A to the U-phase S-pole permanent magnet 23US and the force caused by the magnetic flux flowing from the rotor blade 12B to the V-phase S-pole permanent magnet 23VS are opposite to the rotation direction of the impeller 1, and Since they are of similar magnitude, these forces cancel out. Therefore, when the current flowing in the W phase is maximum, the positional relationship between the stator teeth 212 and the rotor blade 12 is balanced by the positional relationship shown in FIG.

  As time elapses from this state and the current flowing through the U-phase, V-phase, and W-phase coils 22U, 22V, and 22W changes, the magnetic flux generated from the stator 2 changes, thereby inducing the rotor blade 12 As a result, the impeller 1 is rotated.

Again, the current flowing in the U-phase is maximized. By such a cycle, the impeller 1 rotates about the shaft portion as a central axis.
In the artificial heart pump according to the present embodiment, the impeller is rotated based on the operation principle as described above, and therefore can be operated without arranging a permanent magnet on the impeller.

Next, the operation of the artificial heart pump will be specifically described.
When electric power is supplied to the coil, a magnetic field is generated from the stator 2 side, the rotor blade 12 is guided in the circumferential direction, and the impeller 1 rotates about the shaft portion 31D as a central axis. At this time, the impeller 1 rotates around the shaft portion 31 </ b> D without contact with the shaft portion 31 </ b> D by the dynamic pressure generated by the radial dynamic pressure grooves. Further, the impeller 1 has an inner wall surface of the first side wall portion 31B and an inner wall surface of the second side wall portion 31C of the pump housing 31 due to the dynamic pressure generated by the first thrust dynamic pressure groove 14 and the second thrust dynamic pressure groove 15. It can rotate without contacting the wall surface.

  When the impeller 1 is rotated, the pressure on the inner peripheral side of the impeller 1 becomes higher than the pressure on the outer peripheral side by the rotating rotor blade 12 (blade groove 13). Since the area of the blood flow path by the blade groove 13 gradually increases from the inner peripheral side to the outer peripheral side of the impeller 1, a pressure difference can be effectively generated by the diffuser effect.

  Due to the pressure difference caused by the rotation of the impeller 1, the blood in the inflow pipe 4 flows into the pump chamber 311. The blood flowing into the pump chamber 311 enters between the rotating rotor blades 12 (in the blade grooves 13) from the inner peripheral side of the impeller 1, and is pumped in the radial direction (centrifugal direction) by the rotating rotor blades 12. The The blood pumped in the radial direction flows out from the outer peripheral side of the impeller 1, flows between the outer peripheral surface of the impeller 1 and the inner peripheral surface of the cylindrical portion 31 </ b> A of the pump housing 31, and then from the pump chamber 311 to the outflow pipe 5. Spill to

  As described above, in this embodiment, the operation of the artificial heart pump 100 is realized without arranging the permanent magnet 23 on the impeller 1. As a result, even when the impeller 1 is subjected to high temperature treatment when the impeller 1 is coated with a biocompatible material, the permanent magnet 23 is demagnetized because the impeller 1 is not provided with the permanent magnet 23. There is no end to it. Thus, in the present embodiment, it is possible to easily perform a process such as a coating process on the impeller 1.

  In this embodiment, since the axial gap motor system is adopted as the motor system, it is advantageous from the viewpoint of reducing the thickness and size of the artificial heart pump 100.

  Further, in the present embodiment, the rotor blade 12 of the impeller 1 serves both as a rotor tooth that applies a rotational force to the impeller 1 by a magnetic field from the stator 2 side and as a blade that pumps blood by rotation. Therefore, the artificial heart pump 100 can be further reduced in thickness and size.

Second Embodiment
Next, a second embodiment of the present invention will be described.
In the second embodiment, the shape of the impeller is different from that of the first embodiment. Therefore, this point will be mainly described. In the description after the second embodiment, members having the same configurations and functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is simplified or omitted.

FIG. 12 is a perspective view of the impeller according to the second embodiment as viewed from the stator side. FIG. 13 is a front view of the impeller as seen from the stator side, and FIG. 14 is a side view of the impeller.
As shown in these drawings, the impeller 6 is a semi-open impeller 6 and includes an impeller body 61 and a plurality of rotor blades 62 provided so as to protrude from the impeller body 61 toward the stator 2. The rotor blade 62 is formed in a spiral shape. As in the first embodiment, eight rotor blades 62 are provided at a 45 ° pitch (see FIG. 13).

  The rotor blade 62 is formed by forming a plurality of blade grooves 63 on one surface of a laminated structure in which thin ferromagnetic plates such as iron are laminated in the radial direction. The blade groove 63 is formed in a spiral shape, and is curved so that the depth in the circumferential direction gradually becomes deeper in the direction opposite to the rotation direction of the impeller 6. Further, the blade groove 63 is formed to be inclined so that the depth gradually increases from the inner peripheral side to the outer peripheral side of the impeller 1.

  A first thrust dynamic pressure groove 64 is formed on the front surface of the rotor blade 62 along the edge of the impeller 6 on the rotational direction side. 12 and 13 show an example of the first thrust dynamic pressure groove 64, but the shape of the first thrust dynamic pressure groove 64 is not limited to the illustrated shape. For example, a second thrust dynamic pressure groove having a shape as shown in FIG. 5 is also formed on the back side of the impeller body.

  A film (not shown) made of a biocompatible material is provided on the entire surface of the impeller. Since no permanent magnet is disposed on the impeller, the impeller can be easily coated.

  In the impeller 6 according to the second embodiment, since the rotor blade 62 (blade groove 63) is formed in a spiral shape, the pumping force of the artificial heart pump 100 can be improved.

  The shape of the rotor blade 62 of the impeller 6 according to the second embodiment is different from that of the first embodiment, but the change of the shape of the rotor blade 62 is the shape of the blade groove 63 formed in the laminated structure. Can be easily changed.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
In each of the above-described embodiments, the case where the impeller is a semi-open impeller has been described. On the other hand, the third embodiment is different from the above-described embodiments in that the impeller is a closed type impeller. Therefore, this point will be mainly described.

FIG. 15 is a perspective view showing an impeller according to the third embodiment, and FIG. 16 is a side view showing the impeller.
As shown in FIG. 15, the impeller 7 is a closed-type impeller 7, and an impeller body 71 and a plurality of (eight) rotors formed in a spiral shape so as to protrude from the impeller body 71 toward the stator 2. Blade 72. The shape of the rotor blade 72 (the shape of the blade groove 73) is the same shape as in the second embodiment described above.

  Further, the impeller 7 has a shroud portion 75 provided so as to cover the front side of the impeller 7 on the front side of the impeller 7. The shroud portion 75 has a ring-shaped thin plate shape.

  A first thrust dynamic pressure groove 74 is provided in front of the shroud portion 75. FIG. 15 shows an example of the first thrust dynamic pressure groove 74, but the shape of the first thrust dynamic pressure groove 74 is not limited to the illustrated shape. For example, a second thrust dynamic pressure groove having a shape as shown in FIG. 5 is also provided on the back side of the impeller body 71.

  Similar to the impeller body 71 and the rotor blade 72, the shroud portion 75 has a laminated structure in which thin ferromagnetic plates are laminated in the radial direction. Thereby, generation | occurrence | production of the eddy current by the change of the magnetic field generated from the stator side can be suppressed, and energy loss can be reduced.

A film (not shown) made of a biocompatible material is provided on the entire surface of the impeller 7. Since no permanent magnet is disposed on the impeller 7, the coating process on the impeller 7 can be easily performed.
Since the impeller 7 according to the third embodiment is a closed impeller 7 provided with the shroud portion 75, the pumping force of the artificial heart pump 100 can be further improved.

  In the description of the third embodiment, the case where the shape of the rotor blade 72 (blade groove 73) is the same as that of the second embodiment has been described. However, the shape of the rotor blade 72 (blade groove 73) is the same as that of the first embodiment. Of course, it does not matter even if it is the shape of.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described.
In each of the embodiments described above, the case where the rotor blade of the impeller combines the function as the rotor tooth and the function as the blade has been described. On the other hand, the fourth embodiment is different from the above-described embodiments in that the impeller is provided with rotor teeth and blades separately. Therefore, this point will be mainly described.

  FIG. 17 is a side sectional view showing an artificial heart pump according to the fourth embodiment. FIG. 18 is a perspective view of the impeller as seen from the stator side. FIG. 19 is a perspective view of the impeller as seen from the back side.

As shown in FIG. 17, the artificial heart pump 200 includes a housing 3 having a pump housing 33, a stator housing 32, an impeller 8, and a stator 2.
The stator housing 32 and the stator 2 have the same configuration as in the above embodiments.
The pump housing 33 includes a cylindrical tube portion 33A, a disk-shaped first side wall portion 33B disposed on the front side of the impeller 1, and a disk-shaped second wall disposed on the back side of the impeller 1. And a side wall 33C. A shaft portion 33 </ b> D is provided on the first side wall portion 33 </ b> B of the pump housing 33. The shaft portion 33D is provided so as to extend in the z-axis direction from the center of the first side wall portion 33B toward the inside of the pump chamber 331.

  The shaft portion 33D is provided with a communication port 33D-1 that communicates the shaft portion 33D in the axial direction. The communication port 33 </ b> D- 1 is connected to the inside of the inflow pipe 4 and constitutes an inflow path for blood to the pump chamber 331 together with the inflow pipe 4.

  The outer peripheral surface of the shaft portion 33D is arranged to face the inner peripheral surface of the impeller 8 formed in a ring shape with a gap. A radial dynamic pressure groove (not shown) for generating dynamic pressure in the radial direction is provided on the outer peripheral surface of the shaft portion 33D. The impeller 8 can be rotated about the shaft portion 33D without contact with the shaft portion 33D by the dynamic pressure generated by the radial dynamic pressure groove when rotating. The radial dynamic pressure groove may be provided on the inner peripheral surface of the impeller 8.

  As shown in FIGS. 18 and 19, the impeller 8 includes a ring-shaped impeller body 81, a plurality of rotor teeth 82 provided so as to project from the impeller body 81 toward the stator 2, and the rotor teeth 82 project. And a plurality of blades 83 provided so as to protrude on the opposite side of the direction. Further, the impeller 8 includes a member 84 that fills a groove formed between the rotor teeth 82 and the rotor teeth 82. The member 84 is made of, for example, a biocompatible material such as pure titanium, titanium alloy, titanium nitride, polyurethane, or polyester.

Eight rotor teeth 82 and eight blades 83 are provided at a 45 degree pitch.
The shape of the blade 83 (blade groove 85) is the same as the shape of the rotor blade 12 (blade groove 13) in the first embodiment (see FIG. 3 and the like).

  A first thrust dynamic pressure groove 86 is provided on the front side of the impeller 8. Thereby, the impeller 8 can rotate without contact with the inner wall surface of the first side wall portion 33 </ b> B of the pump housing 33. Further, on the back side of the impeller 8, the blade 83 is provided with a second thrust dynamic pressure groove 87. Thereby, the impeller 8 can rotate without contact with the inner wall surface of the second side wall portion 33 </ b> C of the pump housing 33.

The impeller 8 is formed with a coating (not shown) made of a biocompatible material such as pure titanium over the entire surface.
Also in the fourth embodiment, since the permanent magnet 23 is not disposed on the impeller 8, a film can be easily formed on the impeller 8.

The operation of the artificial heart pump 200 according to the fourth embodiment will be briefly described.
When a magnetic field is generated from the stator 2 side, the rotor teeth 82 are guided in the circumferential direction, and the impeller 8 rotates about the shaft portion 33D as a central axis. When the impeller 8 is rotated, the blood in the inflow tube 4 flows into the pump chamber 331 through the communication port 33D-1 of the shaft portion 33D due to the pressure difference of the rotating blade 83. The blood flowing into the pump chamber 331 is pumped in the radial direction (centrifugal direction) by the rotating blade 83 and flows out from the outflow pipe 5.

  In the description of the fourth embodiment, the case where the blade 83 has the same shape as the rotor blade 12 of the first embodiment has been described. However, the shape of the blade 83 is not limited to this, and the shape of the blade 83 may be the same as that of the rotor blade 62 of the second embodiment, or the shroud portion 75 may be provided as in the third embodiment. Absent.

  In the fourth embodiment, it has been described that the number of rotor teeth 82 and blades 83 is eight. However, the number of rotor teeth 82 and blades is not limited to this. The number of rotor teeth 82 and the number of blades 83 may be the same or different.

<Various modifications>
In the above-described embodiments, the configuration using the dynamic pressure bearing has been described for the bearing structure of the impellers 1, 6, 7, and 8. However, the present invention is not limited to this, and the bearing structure of the impeller may be a bearing such as a ball bearing.

  In the description of each of the above-described embodiments, the case where the number of rotor blades 12 (or rotor blades 62 and 72, rotor teeth 82, and so on) is eight and the number of stator teeth 212 is six has been described. . However, the number of rotor blades 12 and stator teeth 212 is not limited to this. Typically, if the number of rotor blades 12 and the number of stator teeth 212 are different (if the pitch of rotor blades 12 and the pitch of stator teeth 212 are different), impeller 1 (or impeller 6, It is possible to rotate 7,8).

  In the description of each of the embodiments described above, the permanent magnets 23 are arranged in the order of the N pole S pole, the N pole S pole, the N pole S pole,... This has been explained (see FIG. 9 etc.). However, the present invention is not limited to this, and the permanent magnets 23 may be arranged in the order of N pole S pole, S pole N pole, N pole S pole,... In this case, the permanent magnets 23 are arranged so that the magnetic poles are alternately different in the circumferential direction with respect to one stator tooth 212.

  In the description of each of the above-described embodiments, it has been described that two permanent magnets 23N and 23S are arranged for one stator tooth 212. However, the present invention is not limited to this, and one permanent magnet 23 may be arranged for one stator tooth 212. Alternatively, three or more permanent magnets 23 may be arranged for one stator tooth 212. Also in these cases, the permanent magnets 23 are arranged so that the magnetic poles are alternately different along the circumferential direction of the rotating shaft.

  In each of the embodiments described above, the centrifugal artificial heart pump has been described. However, it is also possible to configure an axial flow artificial heart pump by changing the shape of the rotor blade and the like.

Although the artificial heart pump has been described above, the present technology can be applied to any pump as long as it is a pump that supplies power to the fluid or conveys the fluid. For example, this technique is applied to the following pumps.
1. In this case, examples of the liquid include oxygen, hydrogen, nitrogen, LNG (Liquefied Natural Gas), DME (DiMethyl Ether), and oil.
2. Gas conveying pump: In this case, examples of the gas include silane, propane, air, nitrogen, chlorofluorocarbon, and chlorofluorocarbon alternative.
3. Refrigerant transport pump: In this case, examples of the fluid include liquid nitrogen, air, oil, silicon oil, methane, ethane, ethylene, chlorofluorocarbon, and chlorofluorocarbon alternative.
Moreover, as a use of a pump, the pump for liquid fuels, a vacuum pump, a compressor, and other pumps are mentioned.

  According to such a pump to which the present technology is applied, the operation of the pump can be realized without disposing a permanent magnet on the impeller. This prevents the permanent magnet from being exposed to the fluid, so that the permanent magnet can avoid adverse effects from high or low temperature fluids, and avoid adverse effects due to the nature of the fluid such as reactive fluids and corrosives. Can do. Thereby, deterioration of a permanent magnet can be suppressed and the expected performance of a pump can be maintained.

  Further, since the coil 22 is also disposed in the stator chamber 321 that is isolated from the pump chamber 311 in which the impeller is disposed, the fluid does not contact the coil. Thereby, it is possible to suppress an adverse effect on the fluid due to the heat generation of the coil, and it is possible to prevent an adverse effect on the coil due to the properties of the fluid such as reactivity and corrosivity.

DESCRIPTION OF SYMBOLS 1, 6, 7, 8 ... Impeller 3 ... Housing 12, 62, 72 ... Rotor blade 22 ... Coil 23 ... Permanent magnet 31, 33 ... Pump housing 32 ... Stator housing 82 ... Rotor tooth 83 ... Blade 100, 200 ... Artificial heart Pump 212 ... Stator teeth 311, 331 ... Pump chamber 321 ... Stator chamber

Claims (2)

A housing having a pump chamber and a stator chamber provided independently of the pump chamber;
An impeller having a plurality of rotor teeth arranged at a first pitch along a circumferential direction of rotation and pumping fluid by rotation;
A plurality of stator teeth each including an opposing surface facing the rotor teeth and arranged at a second pitch different from the first pitch along the circumferential direction, and wound around each of the stator teeth A coil in which electric power having different phases is supplied to the coils adjacent to each other in a direction along the circumferential direction, and provided on the facing surface of each stator tooth, along the circumferential direction. A permanent magnet disposed so that the magnetic poles are alternately different, and a stator disposed opposite to the impeller in the axial direction of the rotation,
The impeller is provided in the pump chamber and pumps fluid in the pump chamber.
The stator is provided in the stator chamber ;
The housing is a pump having a wall portion made of metal and interposed between the impeller and the stator . A housing having a pump chamber and a stator chamber provided independently of the pump chamber;
An impeller having a plurality of rotor teeth arranged at a first pitch along a circumferential direction of rotation and pumping fluid by rotation;
A plurality of stator teeth each including an opposing surface facing the rotor teeth and arranged at a second pitch different from the first pitch along the circumferential direction, and wound around each of the stator teeth A coil in which electric power having different phases is supplied to the coils adjacent to each other in a direction along the circumferential direction, and provided on the facing surface of each stator tooth, along the circumferential direction. A permanent magnet disposed so that the magnetic poles are alternately different, and a stator disposed opposite to the impeller in the axial direction of the rotation,
The impeller is provided in the pump chamber and pumps fluid in the pump chamber.
The stator is provided in the stator chamber ;
The rotor tooth is a rotor blade that is a rotor blade having a function as a blade that pumps the fluid by the rotation .

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