Linear motor

Abstract

To provide a linear motor capable of performing two-stage extension operation.SOLUTION: A linear motor (500) includes: a stator (510); movable elements (520;530) movably arranged along a center axis (CA) with respect to this stator. The movable elements are comprised of: a first movable element (520); and a second movable element (530) that is movably arranged along the center axis (CA) with respect to the first movable element. Each of the stator (510), the first movable element (520), and the second movable element (530) may have a shape which is actually rotation symmetry with respect to the center axis (CA). The second movable element (530) has the center axis (CA) and a column-like shape arranged near the center axis (CA), and the first movable element (520) has a cylindrical shape arranged near an outer periphery of the second movable element. The stator (510) may have a cylindrical shape arranged near the outer periphery of the first movable element.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a linear motor, and particularly to a linear motor used in an injector module such as an injection device.

Background Art

[0002] Various medical robot devices have been developed conventionally. In particular, recently, in order to prevent the novel coronavirus infection (COVID-19) that has spread worldwide, vaccination has been recommended. Such vaccination is sequentially performed on a large number of people using a syringe at a predetermined vaccination site. Therefore, a robot device that can automatically perform such vaccination without human intervention is desired. As is well known, in this vaccination, intramuscular injection is performed. Here, "intramuscular injection" refers to a method of directly injecting a drug such as a vaccine into the muscle deep in the subcutaneous fat.

[0003] For example, Patent Document 1 discloses a disposable syringe that can be used for a vaccination plan. The disposable syringe includes a housing, a plunger body, a drug chamber, an injection needle, and injection moving means (biasing means). The housing has an axis extending from the distal end to the proximal end and a proximal skin contact wall that abuts against the injection site. The contact wall is provided with an opening for receiving the injection needle. The plunger body has a pressure surface facing the skin contact wall in the proximal direction and is arranged to move between a first proximal position and a first distal position. The plunger body can move axially between a first distal position, an intermediate position, and a first proximal position within the housing. The drug chamber is disposed between the pressure surface and the proximal skin contact wall. The drug chamber can move axially and is pressed non-axially by moving the plunger body toward the proximal end. The injection needle is attached to the drug chamber and is arranged to move axially between a third distal position and a third proximal position. The injection moving means (biasing means) is configured to move the plunger body from the first distal position to the first proximal position.

[0004] In the disposable syringe described above, the plunger body, the drug chamber, and the injection needle are compressed such that when the plunger body moves from a first distal position to an intermediate position and the injection needle moves from a third distal position to a third proximal position, the proximal end of the injection needle protrudes distally from the skin contact wall, and when the plunger body moves to the first proximal position, the drug chamber is compressed so that at least a portion of the liquid in the drug chamber is pushed out from the proximal end of the injection needle, and the injection needle moves from a third proximal position to a third distal position.

[0005] However, with this type of disposable syringe, the user (healthcare worker) must retract the plunger body from the first proximal position to the first distal position against the biasing force of the biasing mechanism. In other words, since this disposable syringe requires human intervention, it is not suitable for use as an injection device to be incorporated into a robotic system that can perform the procedure automatically.

[0006] Furthermore, Patent Document 2 discloses an automatic syringe for the rapid discharge of a bolus of injectable drugs. This automatic syringe has a small external dimension and a substantially flat, sealed housing that approximates a credit card. The syringe, configured to be contained within the flat housing, is pre-filled with the drug. The housing includes a mechanism that, when triggered, automatically moves the syringe and needle forward to the injection position, compressing the volume of the syringe and causing rapid injection. The device includes an actuator at the forward injection end, which keeps the needle hidden and protected at all times, preventing post-injection hazards. The flat surface of the device has a graphical symbol and other visible markers related to the operation and conditions of the device. The device allows for simple three-step operation, reducing the risk of misuse.

[0007] In the above automatic syringe, the housing consists of a cover and a peelable elongated strip that interact with each other. The device includes an actuator assembly and a syringe carrier assembly. The actuator assembly includes a substantially flat needle shield and a pair of arms extending rearward from the shield. The actuator assembly is held in the retracted position by a pair of releasable arm locks. The actuator assembly is biased forward by a pair of longitudinally positioned side compression springs. The syringe has a flat configuration and is defined by a flat piston-type device comprising a cup-shaped container. The open end of the cup-shaped container receives a piston that carries the injection needle. The front end of the piston includes a needle carrier, which holds the injection needle aligned with the partition and space. The needle carrier includes a longitudinally foldable, forward-extending, bellows-like support. The needle is fixed to an anchor embedded within the needle support, along with a portion of the needle. The syringe assembly is biased by a syringe compression spring (drive spring). Once the needle penetrates the tissue to the intended depth, the needle support rests on the rear surface of the needle shield. A return opening is formed on each of the arms behind the opening.

[0008] An automatic syringe of this configuration operates as follows: After removing the detachable elongated strip and cover, the needle shield of the actuator assembly is pressed against the patient's skin, and the syringe carrier is centrifugally driven away from its latched position under the biasing force of a sufficiently powerful drive spring, piercing the skin and penetrating the tissue to the intended depth. When the needle support contacts the rear surface, the sharp front end of the needle penetrates the patient's tissue to the intended depth. The continuous biasing force of the drive spring advances the syringe carrier and container forward on the then-stationary piston, folding the volume within the syringe and causing a bolus of medication to be injected into the patient. When the compression of the syringe volume is complete, the injection is finished. As the injection stroke approaches its end, the arm lock is released. With the actuator assembly arm free, the actuator assembly moves relatively forward of the housing under the biasing force of the side spring so that the device can be retracted. The needle shield extends to cover and protect the front end of the needle, and an arm lock is dropped into the rear opening to lock the actuator assembly and the needle shield into a centrifugal-extended needle protection configuration. When the needle shield extends to its centrifugal-locked position, biological hazard markers on the flat surface of the shield are conspicuously exposed to serve their warning function.

[0009] However, automatic syringes with this configuration are not intended for use by medical professionals, but rather for individual use by patients themselves. Therefore, such automatic syringes are not intended for use as vaccine syringes in vaccination sites as described above. Furthermore, because they contain actuators, automatic syringes have a very complex structure. For this reason, it is desirable for injection devices to be incorporated into the above-mentioned robotic device to have a simplified syringe structure and to use an external actuator (hereinafter referred to as "external actuator") that is separate from the syringe.

[0010] Various types of external actuators can be considered, but for example, a linear motor can be used. There are various types of linear motors, but when a large driving force is not required, they are often composed of a combination of permanent magnets and coils. Also, as is well known, linear motors are broadly classified into two types: "moving magnet type linear motors" and "moving coil type linear motors".

[0011] In a moving magnet type linear motor, the movable element includes a permanent magnet, and the stator includes a coil (excitation coil) (see, for example, Patent Documents 3, 4, 5, 6, and 7).

[0012] On the other hand, a moving coil type linear motor includes a coil (armature coil) as the movable element and a permanent magnet as the stator (for example, Patent Documents 8 and 9).

[0013] Whether it is a moving magnet linear motor or a moving coil linear motor, the operating principle of a linear motor is to utilize the thrust generated by the interaction between the magnetic flux generated by the permanent magnet and the current flowing through the coil (the so-called Fleming's left-hand rule). In other words, any well-known linear motor consists of a stator and a movable element that is movably positioned along the central axis relative to the stator. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Special Publication No. 2016-517742 [Patent Document 2] U.S. Patent No. 6979316 [Patent Document 3] Patent No. 2781912 [Patent Document 4] Japanese Patent Publication No. 2001-086725 [Patent Document 5] Japanese Patent Publication No. 2009-050128 [Patent Document 6] Patent No. 5068494 [Patent Document 7] Patent No. 4068848 [Patent Document 8] Patent No. 3852117 [Patent Document 9] Japanese Patent Publication No. 2007-209176 [Overview of the project] [Problems that the invention aims to solve]

[0015] However, when attempting to use the well-known linear motor described above as an external actuator installed outside the syringe, the following problems arise.

[0016] To elaborate, the well-known linear motor described above can only move one movable element along the central axis relative to the stator. That is, it only moves one driven element associated with (connected to or in contact with) one movable element along the central axis. In other words, the well-known linear motor can only perform a simple extension motion that moves only one driven element.

[0017] On the one hand, when attempting to perform the above-mentioned intramuscular injection, it is necessary to use an external actuator to cause the syringe to perform the operations of at least the following three steps (the first step, the second step, and the third step). The first step is a step of protruding the injection needle from the front surface of the syringe housing to reach the tip of the injection needle to the muscle of a person (hereinafter referred to as the "injection needle protrusion step"). The second step is a step of extruding the drug solution from the tip of the injection needle into the muscle (hereinafter referred to as the "drug solution extrusion step"). The third step is a step of retracting the protruding injection needle into the syringe housing (hereinafter referred to as the "injection needle retraction step"). That is, as an external actuator for a syringe, it is necessary to move at least two different driven bodies, namely, a first driven body for moving only the injection needle and a second driven body for extruding the drug solution. In other words, as an external actuator for a syringe, a linear motor capable of performing at least a two-stage stretching operation is required.

[0018] However, as described above, it is difficult for a well-known linear motor to perform at least a two-stage stretching operation for moving a plurality of driven bodies.

[0019] An object of the present invention is to provide a linear motor capable of performing a two-stage stretching operation.

Means for Solving the Problem

[0020] According to one aspect of the present invention, in a linear motor including a stator and a mover movably disposed along a central axis with respect to the stator, the mover includes a first mover and a second mover movably disposed along the central axis with respect to the first mover, and a linear motor is provided.

[0021] In the above linear motor, each of the stator, the first mover, and the second mover may have a shape that is substantially rotationally symmetric with respect to the central axis.

[0022] Furthermore, the second movable element may have a cylindrical shape positioned at or near its central axis; the first movable element may have a cylindrical shape positioned near the outer circumference of the second movable element; and the stator may have a cylindrical shape positioned near the outer circumference of the first movable element.

[0023] The first movable element may have an annular cross-sectional shape and include a plurality of permanent magnets arranged along a central axis. In this case, the plurality of permanent magnets generate outer magnetic flux and inner magnetic flux on their outer and inner circumferences, respectively. The stator may include a plurality of outer electromagnet coils arranged continuously along a central axis so as to surround the first movable element with an outer gap between them. In this case, the interaction between the outer current flowing through the plurality of outer electromagnet coils and the outer magnetic flux allows the stator to move the first movable element along a central axis. The second movable element may include a plurality of inner electromagnet coils arranged continuously along a central axis so as to surround the first movable element with an inner gap between them. In this case, the interaction between the inner current flowing through the plurality of inner electromagnet coils and the inner magnetic flux allows the second movable element to move along a central axis relative to the first movable element.

[0024] Furthermore, the stator may include a star-connected outer U-phase coil, outer V-phase coil, and outer W-phase coil as coils for multiple outer electromagnets. Similarly, the second movable element may include a star-connected inner U-phase coil, inner V-phase coil, and inner W-phase coil as coils for multiple inner electromagnets. In this case, the linear motor consists of a three-phase linear motor.

[0025] Each of the multiple permanent magnets should have a length three times that of the coils in each phase, and it is desirable that the multiple permanent magnets be arranged in series along the central axis such that adjacent magnetic poles are like and in close contact with each other.

[0026] The movable element may be configured to move in a first direction along the central axis relative to the stator when an external current is passed through a plurality of external electromagnet coils of the stator. Similarly, the second movable element may be configured to move in a first direction along the central axis relative to the first movable element when an internal current is passed through a plurality of internal electromagnet coils of the second movable element. In such a configuration, it is preferable that the linear motor further comprises: a first biasing means for biasing the movable element in a second direction opposite to the first direction when the flow of external current is stopped; and a second biasing means for biasing the second movable element in a second direction when the flow of internal current is stopped.

[0027] Preferably, the linear motor further comprises: a base arranged parallel to the central axis; a guide rail attached to the base parallel to the central axis; first and second brackets erected from the base and holding the stator at the end in a first direction and the end in a second direction opposite to the first direction, respectively; and first and second sliding members slidably mounted on the guide rail and holding the first movable element at both ends at positions spaced apart from the first and second brackets in the first and second directions, respectively.

[0028] Preferably, the linear motor further comprises: another bracket having an opening, erected on the base on the first side of the first bracket; a hollow first operating portion extending from the first sliding member in the first direction along the central axis and capable of passing through the opening of the other bracket; and a second operating portion extending from the first end of the second movable element in the first direction along the central axis and inserted spaced apart inside the first operating portion.

[0029] In the linear motor described above, the first biasing means may be positioned between the first sliding member and another bracket, and the second biasing means may be positioned in a space formed on the second direction side of the first sliding member and on the inner circumference side of the first movable element. [Effects of the Invention]

[0030] According to the linear motor of the present invention, it is possible to perform a two-stage extension operation that moves two different driven objects. [Brief explanation of the drawing]

[0031] [Figure 1] This is a perspective view of the automated vaccine administration robot device to which the present invention is applied, taken from the front right at an angle, together with the person being vaccinated. [Figure 2] Figure 1 is a schematic right-side view of the automated vaccine administration robot device, as seen from approximately the right side, along with the person being vaccinated. [Figure 3] Figure 1 shows the external appearance of the automated vaccine administration robot device, viewed from the diagonal right rear, together with the person being vaccinated. [Figure 4] This is a perspective cross-sectional view of a cartridge injector, operated by an external actuator used as a linear motor according to the present invention, viewed from the front right at an angle. [Figure 5] Figure 4 is a schematic right-hand cross-sectional view of the cartridge injector, viewed from approximately the right side. [Figure 6] Figure 4 is a cross-sectional view of the cartridge injector, taken from the rear right at an oblique angle. [Figure 7] This is a perspective cross-sectional view of a linear motor according to one embodiment of the present invention, viewed from the front right, together with a cartridge injector located in the operating section. [Figure 8] Figure 7 shows a schematic right-hand cross-sectional view of the linear motor, along with the cartridge injector located in the operating section, viewed from approximately the right side. [Figure 9] Figure 7 is a perspective cross-sectional view of the linear motor shown, along with the cartridge injector located in the operating section, viewed from the rear right. [Figure 10] These are cross-sectional views illustrating the magnetic flux generated by multiple permanent magnets in the first movable element used in the linear motor shown in Figures 7 to 9. [Figure 11]Figures 7 to 9 illustrate an example of how to connect each coil to a control driver when using nine coils as electromagnets for the stator and second movable element in a linear motor. [Modes for carrying out the invention]

[0032] (An example of an apparatus to which the present invention is applied) To facilitate understanding of the present invention, an automated vaccination robot device 100, which is a type of medical robot device, will be described as an apparatus to which the present invention is applied. This automated vaccination robot device 100 is a robot device that automatically performs vaccination to prevent infectious diseases such as COVID-19.

[0033] Figures 1 to 3 show the external appearance of the automated vaccine administration robot device 100 together with a person 200 to be vaccinated. Figure 1 is a perspective view of the external appearance of the automated vaccine administration robot device 100, viewed from the front right. Figure 2 is a schematic right side view of the external appearance of the automated vaccine administration robot device 100, viewed from approximately the right side. Figure 3 is a perspective view of the external appearance of the automated vaccine administration robot device 100, viewed from the rear right.

[0034] Here, as shown in Figures 1 to 3, a Cartesian coordinate system (X,Y,Z) is used. In the state shown in Figures 1 to 3, in the Cartesian coordinate system (X,Y,Z), the X-axis direction is the front-back direction, the Y-axis direction is the left-right direction perpendicular to the X-axis direction, and the Z-axis direction is the up-down direction perpendicular to both the X-axis and Y-axis directions. Therefore, the X-axis direction extends in the forward direction X1 and the backward direction X2, the Y-axis direction extends in the rightward direction Y1 and the leftward direction Y2, and the Z-axis direction extends in the upward direction Z1 and the downward direction Z2. In this specification, the forward direction X1 is also called the forward direction or direction of travel, and the backward direction X2, which is the opposite direction to the forward direction X1, is also called the backward direction or direction of retreat. The Cartesian coordinate system (X,Y,Z) described above will also be used in subsequent drawings. In this specification, the forward direction X1 is also called the "first direction," and the backward direction X2 is also called the "second direction." In this specification, "before" and "after" may be replaced with "first" and "second," respectively, as appropriate.

[0035] As is clear from Figures 1 to 3, at the position X1 in front of the automated vaccination robot device 100 (vaccination position), the person to be vaccinated, 200, is seated in a chair 300 with their face turned to the right Y1. In other words, in the illustrated example, the automated vaccination robot device 100 is a device that administers the vaccine to the person 200 by intramuscular injection into the left upper arm 210.

[0036] The automated vaccine administration robot device 100 includes a base 110, first to fourth arms 121, 122, 123, and 124, and an injector module 130. The first to fourth arms 121 to 124 are arranged in this order upward Z1 from the base 110. The injector module 130 is attached to the upper end of the fourth arm 124. In the illustrated example, the base 110 is fixed to the floor surface, but it may be a movable base configured to move on the floor surface in the X-axis and Y-axis directions.

[0037] The base 110 incorporates a controller (not shown) and a power supply (not shown) for controlling the automatic vaccination robot device 100. Alternatively, instead of incorporating a power supply, the automatic vaccination robot device 100 may be configured to receive power from an external power supply via wired or wireless connection. The controller is connected to an external computer (not shown) via wired or wireless connection. The controller receives various commands from the computer to operate the automatic vaccination robot device 100. The controller controls the operation of the automatic vaccination robot device 100 according to these commands.

[0038] The base 110 and the first to fourth arms 121-124 are connected via the first to fourth joints 141, 142, 143, and 144. More specifically, the lower end of the first arm 121 is rotatably connected to the upper surface of the base 110 via the first joint 141. The upper end of the first arm 121 and the lower end of the second arm 122 are connected via the second joint 142 so as to be rotatable around the axis of rotation of the second joint 142. The upper end of the second arm 122 and the lower end of the third arm 123 are connected via the third joint 143 so as to be rotatable around the axis of rotation of the third joint 143. The upper end of the third arm 123 and the lower end of the fourth arm 124 are connected via the fourth joint 144, so as to be rotatable around the rotation axis of the fourth joint 144. The first to fourth joints 141 to 144 are each driven by first to fourth motors (not shown). The first to fourth motors rotate the first to fourth joints 141 to 144, each based on control signals sent from the controller.

[0039] The injector module 130, attached to the upper end of the fourth arm 124, is an injection device for administering vaccine to the person 200. That is, the injector module 130 operates as an injection device incorporated into the automated vaccine administration robot device 100. The injector module 130 administers vaccine to the left upper arm 210 of the person 200 in accordance with the operation commands sent from the controller, as described later.

[0040] The injector module 130 includes a first housing 131 that covers an external actuator (described later) and a second housing 132 that covers a plurality of cartridge injectors (described later) driven by the external actuator. The second housing 132 incorporates a magazine device (not shown) configured to load a plurality of cartridge injectors.

[0041] More specifically, the second housing 132 houses a standby chamber (not shown), a waste chamber (not shown), and an operating section (described later). In its initial state, the standby chamber holds and houses all of the multiple cartridge injectors. The waste chamber is for storing used cartridge injectors. The magazine device operates to sequentially feed the multiple cartridge injectors one by one from the standby chamber to the operating section, and then to move the used cartridge injectors from the operating section to the waste chamber. The magazine device performs the loading operation described above in accordance with the loading command sent from the controller.

[0042] Meanwhile, the cartridge injector delivered to the control unit is operated by an external actuator, as will be described later, to administer the vaccine to the left upper arm 210 of person 200. In other words, the cartridge injector delivered to the control unit functions as a simple syringe for intramuscular injection.

[0043] Next, with reference to Figures 4 to 6, the configuration of the cartridge injector 400 fed into the operating unit will be described. Figure 4 is a perspective cross-sectional view of the cartridge injector 400 seen from the front right. Figure 5 is a schematic right-side cross-sectional view of the cartridge injector 400 seen from approximately the right side. Figure 6 is a perspective cross-sectional view of the cartridge injector 400 seen from the rear right.

[0044] As mentioned above, Figures 4 to 6 also use the same Cartesian coordinate system (X,Y,Z) as shown in Figures 1 to 3. Since the Cartesian coordinate system (X,Y,Z) used has already been described in detail, its explanation will be omitted for brevity.

[0045] As is clear from Figures 4 to 6, the cartridge injector 400 has a shape that is substantially rotationally symmetric with respect to a central axis CA extending in the front-rear direction X. The cartridge injector 400 includes a hollow housing 410 that extends along the central axis CA. The housing 410 is made of metal or resin. The housing 410 is cylindrical with a first inner wall 411 having a first inner diameter Di1 and an open rear end. The housing 410 has a tapered tip 412 in its front direction X1. The housing 410 has a cylindrical opening 4121 with a diameter Da that allows the injection needle (catheter) 420, described later, to protrude and retract. The diameter Da is smaller than the first inner diameter Di1. The opening 4121 of the tip 412 is sealed with silicone (not shown). Therefore, the injection needle (catheter) 420 is shaped to penetrate the silicone.

[0046] The injection needle (catheter) 420 is provided within the housing 410, extending along the central axis CA on its forward X1 (first direction) side. The injection needle (catheter) 420 is substantially cylindrical, and its tip 421 is cut at an angle. The rear end portion 422 of the injection needle (catheter) 420 is held by the first movable body 430 via a retaining member 440.

[0047] The first movable body 430 is positioned within the housing 410 so as to be movable in the front-rear direction X while sliding against the inner wall 411 along the central axis CA. More specifically, the first movable body 430 consists of a rear end portion 432 on the rearward direction X2 (first direction) side, a front end portion 434 on the forward direction X1 (first direction) side, and an intermediate portion 436 positioned between the rear end portion 432 and the front end portion 434.

[0048] The rear end portion 432 has a cylindrical portion and four protrusions projecting radially outward from the cylindrical portion in the upward Z1, downward Z2, rightward Y1, and leftward Y2 directions. The four protrusions extend in the front-rear direction X. The outer circumferential surface that virtually connects the radially outward tip surfaces of the four protrusions of the rear end portion 432 in the circumferential direction forms an outer wall 4321 with an outer diameter substantially equal to the first inner diameter Di1. The cylindrical portion of the rear end portion 432 has an inner wall 4322 with a second inner diameter Di2 that is smaller than the first inner diameter Di1. Therefore, the outer wall 4321 of the rear end portion 432 slides against the first inner wall 411 of the housing 410.

[0049] The intermediate section 436 is cylindrical, having the same shape as the cylindrical section of the rear end 432. The intermediate section 436 has an outer wall 4361 with a first outer diameter Do1 smaller than the first inner diameter Di1, and an inner wall 4362 with an inner diameter equal to the second inner diameter Di2. Therefore, the inner wall 4322 of the rear end 432 and the inner wall 4362 of the intermediate section 436 are continuous, sharing the same second inner diameter Di2. There is also a gap between the outer wall 4361 of the intermediate section 436 and the inner wall 411 of the housing 410. The rear end of the spring 450, which will be described later, is positioned in this gap.

[0050] The cylindrical space with a second inner diameter Di2, enclosed by the inner wall 4322 of the rear end portion 432 and the inner wall 4362 of the intermediate portion 436, functions as a containment space AS for containing the chemical solution (liquid agent) described later. Therefore, the inner wall 4322 of the rear end portion 432 and the inner wall 4362 of the intermediate portion 436 both act as a second inner wall for forming the containment space AS.

[0051] The front end portion 434 has a cross-shaped outer form when viewed from the front, and has a cylindrical inner wall 4342 in the center. The distance between the outer walls 4341 that are virtually formed circumferentially at the widest distances from each other on the cross-shaped outer form of the front end portion 434 has a second outer diameter Do2 that is smaller than the first outer diameter Do1. Also, the inner wall 4342 of the front end portion 434 has a third inner diameter Di3 that is smaller than the second inner diameter Di2. The holding member 440 is positioned on this inner wall 4342 of the front end portion 434. Therefore, the rear end portion 422 of the injection needle (catheter) 420 is held by the front end portion 434 of the first movable body 430 via the holding member 440. Note that the cylindrical internal space of the injection needle (catheter) 420 is in communication with the housing space AS.

[0052] Therefore, the first movable body 430 acts as a first piston, reciprocating in the forward / backward direction X along the central axis CA within the first cylinder, with the housing 410 acting as the first cylinder. The first movable body 430 is moved forward in the direction X1 along the central axis CA by the first movable element (first operating part) of the external actuator, which will be described later. Therefore, the first movable body 430 acts as a first driven body that moves the injection needle (catheter) 420 forward in the direction X1 along the central axis CA.

[0053] Note that the cartridge injector 400 shown in Figures 4 to 6 represents the initial state. The housing 410 has a rear end portion 413 in the rear direction X2 (second direction). The rear end portion 413 has a projection 4131 that protrudes radially inward from the inner wall 411 of the housing 410. Therefore, the inner diameter of the projection 4131 is slightly smaller than the first inner diameter Di1. In the initial state, the rear ends 432b of the four protrusions of the rear end portion 432 of the first movable body 430 and the projection 4131 of the rear end portion 413 of the housing 410 are engaged. Here, "engagement" means being related.

[0054] Inside the housing 410, the spring 450 is positioned on its front-facing side X1 (first direction). The spring 450 extends in the front-rear direction X along the central axis CA. The spring 450 has a front end 451 in the front-facing direction X1 (first direction) and a rear end 452 in the rear-facing direction X2 (second direction). The front end 451a of the front end 451 of the spring 450 engages with the rear end 412b of the front end 412 of the housing 410. As described above, the rear end 452 of the spring 450 is positioned in the gap formed between the outer wall 4361 of the intermediate portion 436 of the first movable body 430 and the inner wall 411 of the housing 410. The rear end 452b of the rear end 452 of the spring 450 engages with the front ends 432a of the four protrusions of the rear end 432 of the first movable body 430.

[0055] Therefore, the spring 450 is positioned along the central axis CA between the front end 412 of the housing 410 and the rear end 432 of the first movable body 430. As mentioned above, Figures 4 to 6 show the initial state of the cartridge injector 400. In this initial state, the spring 450 does not exert any biasing force on the first movable body 430 located inside the housing 410. However, when the first movable body 430 attempts to move forward X1 (first direction) along the central axis CA, the spring 440, with its biasing force, biases the first movable body 430 backward X2 (second direction) relative to the housing 410. In other words, the spring 450 acts as a biasing means that biases the first movable body 430 backward X2 (second direction) along the central axis CA relative to the housing 410. Therefore, in the initial state, the spring 450 locks the rear end 432b of the rear end 432 of the first movable body 430 with the protrusion 4131 of the rear end 413 of the housing 410. Here, "locking" means being intertwined and stopped.

[0056] Therefore, the first movable body 430, together with the second movable body 460 (described later), is moved from its initial state in the forward direction X1 (first direction) along the central axis CA against the biasing force of the spring 450 by the first movable element (first operating part) of the external actuator, which will be described later. Furthermore, when the first driving force (first thrust; first Lorentz force) of the first movable element of the external actuator disappears, the first movable body 430 can return to its initial state due to the biasing force of the spring 450.

[0057] As mentioned above, the cylindrical space enclosed by the second inner wall 4322 of the rear end 432 and the second inner wall 4362 of the intermediate portion 436 of the first movable body 430 is a storage space AS for containing the drug solution (liquid agent). The second movable body 460 is positioned on the rearward X2 (second direction) side of this storage space AS. The second movable body 460 has a substantially cylindrical outer shape and is movable in the forward direction X1 along the central axis CA. The outer circumferential wall of the second movable body 460 has substantially the same outer diameter as the second inner diameter Di2 of the second inner wall 4322 of the rear end 432 and the second inner wall 4362 of the intermediate portion 436 of the first movable body 430. That is, the outer circumferential wall of the second movable body 460 is slidable relative to the second inner walls (4322; 4362) of the first movable body 430.

[0058] The second movable body 460 consists of a front member 462 provided in the forward direction X1 (first direction) and a rear member 464 provided in the rear direction X2 (second direction). The front member 462 and the rear member 464 are connected and combined with each other like a lock and key. The front member 462 functions as a gasket (packing). The front member 462 has a circular front wall surface 462a in the forward direction X1 (first direction). The rear member 464 has an annular rear wall surface 464b in the rear direction X2 (second direction). Therefore, to be more precise, the above-mentioned containment space AS is a cylindrical space enclosed by the second inner wall 4322 of the rear end portion 432 of the first movable body 430, the second inner wall 4362 of the intermediate portion 436, the annular rear wall surface 434b of the front end portion 434, and the front wall surface 462a of the second movable body 460. This containment space AS contracts as the second movable body 460 moves relative to the first movable body 430 in the forward direction X1 (first direction). Due to this contraction of the containment space AS, the drug solution (liquid agent) contained in the containment space AS is released to the outside through the internal space of the injection needle (catheter) 420.

[0059] Therefore, the second movable body 460 acts as a second piston, capable of reciprocating in the forward / backward direction X along the central axis CA within the second cylinder, with the first movable body 430 acting as the second cylinder. The second movable body 460 is moved forward in the first direction X1 along the central axis CA by the second movable element (second operating part) of the external actuator, which will be described later. Therefore, the second movable body 460 acts as a second driven body for pushing the chemical solution (liquid agent) in the containment space AS forward in the first direction X1 along the central axis CA.

[0060] A cartridge injector 400 with this configuration is operated as follows. First, as mentioned above, the combination of the first movable body 430 and the second movable body 460 is moved forward X1 (first direction) along the central axis CA from its initial state against the biasing force of the spring 450 by the first movable element (first operating part) of the external actuator. As a result, the injection needle (catheter) 420 protrudes forward X1 (first direction) from the opening 4121 of the housing 410 along the central axis CA, and the tip 421 of the injection needle (catheter) 420 reaches the muscle from the left upper arm 210 of the person 200 (see Figures 1 to 3). Subsequently, the second movable element (second operating part) of the external actuator pushes the drug solution (liquid) in the containment space AS forward X1 (first direction) along the central axis CA by the second movable body 460. As a result, the drug solution (liquid) contained within the containment space AS is pushed into the muscle of the person 200 through the internal space of the injection needle (catheter) 420. Subsequently, the driving force (thrust; Lorentz force) of the first and second movable elements of the external actuator disappears. As a result, the protruding injection needle (catheter) 420 is automatically retracted into the housing 410 by the biasing force of the spring 450.

[0061] Furthermore, the first movable body 430 is also called the outer cylinder, and the second movable body 460 is also called the inner cylinder.

[0062] Next, with reference to Figures 7 to 9, the configuration of the linear motor 500 used as an external actuator for driving the cartridge injector 400 shown in Figures 4 to 6 will be described. Figure 7 is a perspective cross-sectional view of the linear motor 500 together with the cartridge injector 400 located in the operating section of the second housing 132, viewed from the front right. Figure 8 is a schematic right-side cross-sectional view of the linear motor 500 together with the cartridge injector 400 located in the operating section of the second housing 132, viewed from approximately the right side. Figure 9 is a perspective cross-sectional view of the linear motor 500 together with the cartridge injector 400 located in the operating section of the second housing 132, viewed from the rear right.

[0063] As mentioned above, Figures 7 to 9 also use the same Cartesian coordinate system (X,Y,Z) as shown in Figures 1 to 3. Since the Cartesian coordinate system (X,Y,Z) used has already been described in detail, its explanation will be omitted for brevity.

[0064] Before describing the configuration of the linear motor 500, we will first describe the configuration of the injector module 130 surrounding the linear motor 500 (i.e., the components surrounding the linear motor 500).

[0065] As described with reference to Figures 1 to 3, the injector module 130 includes a first housing 131 that covers a linear motor 500, which is an external actuator, and a second housing 132 that covers a plurality of cartridge injectors 400. The injector module 130 has a base 133 that extends in the front-rear direction X parallel to the central axis CA inside the first housing 131 and the second housing 132. The base 133 has a front end 133a inside the second housing 132 and a rear end 133b inside the first housing 131. Inside the second housing 132, a retaining block 134 that holds the cartridge injector 400 in operation is erected on the front-rear direction X1 (first direction) side of the base 133, extending upward Z1 from the base 133. Therefore, this retaining block 134 constitutes the operating section of the second housing 132.

[0066] Within the first housing 131, the first and second brackets 136 and 137, and another bracket 138 are erected upward Z1 from the base 133. The other bracket 138 is provided in close proximity to the holding block 134, separated by a predetermined distance L1. The first bracket 136 is erected from approximately the center of the base 133. The second bracket 137 is erected on the rearward X2 (second direction) side of the base 133. The first and second brackets 136 and 137 are for holding the stator of the linear motor 500, which will be described later.

[0067] A guide rail 150 is laid on the base 133 along the central axis CA. The guide rail 150 has a front end 150a in the forward direction X1 (first direction) and a rear end 150b in the rear direction X2 (second direction). The front end 150a of the guide rail 150 is located between another bracket 138 and the first bracket 136. The rear end 150b of the guide rail 150 is located between the second bracket 137 and the rear end 133b of the base 133, and is close to the rear end 133b of the base 133. First and second sliding members 151 and 152 are erected on the guide rail 150, and are slidable in the front-rear direction X parallel to the central axis CA. The first sliding member 151 is configured to slide between another bracket 138 and the first bracket 136 on the guide rail 150 in the front-rear direction X parallel to the central axis CA. The second sliding member 152 is configured to slide in the front-rear direction X parallel to the central axis CA on the guide rail 150 between the second bracket 137 and the rear end 133b of the base 133 (the rear end 150b of the guide rail 150).

[0068] The first and second sliding members 151 and 152 are for holding the first movable element of the linear motor 500, which will be described later. Therefore, the first movable element of the linear motor 500 is movable in the front-rear direction X along the central axis CA above the guide rail 150 together with the first and second sliding members 151 and 152.

[0069] Next, with reference to Figures 7 to 9, the configuration of the linear motor 500 for driving the cartridge injector 400 held by the holding block 134 will be described. First, the main components of the linear motor 500 will be described, and then the accessory components of the linear motor 500 will be described.

[0070] As is clear from Figures 7 to 9, the main body of the linear motor 500, like the cartridge injector 400, has a shape that is substantially rotationally symmetric with respect to the central axis CA extending in the front-rear direction X. Therefore, the cartridge injector 400 and the main body of the linear motor 500, which are held by the holding block 134, share the same central axis CA.

[0071] The linear motor 500 includes a stator 510 and a movable element as its main components. The movable element is positioned to move freely in the forward / backward direction X along the central axis CA relative to the stator 510. The movable element consists of a first movable element 520 and a second movable element 530. The first movable element 520 is positioned to move freely in the forward / backward direction X along the central axis CA relative to the stator 510. The second movable element 530 is positioned to move freely in the forward / backward direction X along the central axis CA relative to the first movable element 520. Thus, since the linear motor 500 has two movable elements 520 and 530, it is possible to perform a two-stage extension operation to move two different driven parts 430 and 460 of the cartridge injector 400. Hereinafter, the movable element consisting of the combination of the first movable element 520 and the second movable element 530 will be referred to as the movable element (520; 530).

[0072] In the illustrated example, the second movable element 530 is substantially cylindrical in shape and positioned on and near the central axis CA. The first movable element 520 is substantially cylindrical in shape and positioned near the outer circumference of the second movable element 530. The stator 510 is substantially cylindrical in shape and positioned near the outer circumference of the first movable element 520.

[0073] More specifically, the first movable element 520 has an annular cross-sectional shape and includes a plurality of cylindrical permanent magnets 522 arranged along a central axis CA. In the illustrated example, the first movable element 520 includes four permanent magnets 522. The plurality of permanent magnets 522 generate an outer magnetic flux OM and an inner magnetic flux IM at their outer and inner circumferences, respectively, as shown in Figure 10.

[0074] The stator 510 includes a plurality of outer electromagnet coils 512 arranged continuously along the central axis CA so as to surround the first movable element 520, with an outer gap between them. In the illustrated example, the stator 510 includes 15 outer electromagnet coils 512. The interaction between the outer current flowing through the plurality of outer electromagnet coils 512 and the outer magnetic flux OM allows the stator 510 to move the first movable element 520 along the central axis CA. At this time, the second movable element 530 is also moved along the central axis CA together with the first movable element 520. Thus, the interaction between the outer current and the outer magnetic flux OM allows the stator 510 to move the movable elements (520; 530) along the central axis CA.

[0075] The second movable element 530 includes a plurality of internal electromagnet coils 532 arranged continuously along the central axis CA so as to be surrounded by the first movable element 520, with an internal gap between them. In the illustrated example, the second movable element 530 includes 12 internal electromagnet coils 532. The interaction between the internal current flowing through the plurality of internal electromagnet coils 532 and the internal magnetic flux IM allows the second movable element 530 to travel along the central axis CA relative to the first movable element 520.

[0076] The stator 510 includes star-connected outer U-phase coils, outer V-phase coils, and outer W-phase coils as a plurality of outer electromagnet coils 512. Similarly, the second movable element 530 includes star-connected inner U-phase coils, inner V-phase coils, and inner W-phase coils as a plurality of inner electromagnet coils 532. Thus, the linear motor 500 consists of a three-phase linear motor.

[0077] Referring to Figure 11, the U-phase coil, V-phase coil, and W-phase coil used as multiple outer electromagnet coils 512 or multiple inner electromagnet coils 532 will be described.

[0078] Figure 11 shows connection examples when the basic configuration consists of three sets of three U-phase coils, one W-phase coil, and one V-phase coil, i.e., a total of nine coils, and when using the control driver 600. When the control driver 600 is connected to a single-phase 100V AC power supply 700, it has a built-in single-phase to three-phase converter, and the U-phase, V-phase, and W-phase are connected to the U-phase, V-phase, and W-phase coils, respectively. However, the U-phase, V-phase, and W-phase of the power supply are not necessarily connected in a one-to-one relationship to the U-phase, V-phase, and W-phase coils. There are various ways to connect the power supply to the U-phase, V-phase, and W-phase coils.

[0079] The control driver 600 is also connected to the aforementioned computer, such as a personal computer, as a control data input means and a data processing means. Based on operation commands provided by the computer, the control driver 600 controls the operation of the first movable element 520 or the second movable element 530.

[0080] Here, for the U-phase coils, the starting end S of the first coil U1 is connected to the U terminal of the control driver 600, and the ending end E of the first coil U1 is connected to the ending end E of the second coil U2. Then, the starting end S of the second coil U2 is connected to the starting end S of the third coil U3, and the ending end E of the third coil U3 is connected to the common terminal. Similarly, for the W-phase coils, the ending end E of the first coil W1 is connected to the W terminal of the control driver 600, and the starting end S of the first coil W1 is connected to the starting end S of the second coil W2. Then, the ending end E of the second coil W2 is connected to the ending end E of the third coil W3, and the starting end S of the third coil W3 is connected to the common terminal. On the other hand, for the V-phase coils, the starting end S of the first coil V1 is connected to the V terminal of the control driver 600, and the ending end E of the first coil V1 is connected to the ending end E of the second coil V2. Then, the starting end S of the second coil V2 is connected to the starting end S of the third coil V3, and the ending end E of the third coil V3 is connected to the common terminal.

[0081] Simply put, in the case of having nine coils as shown in Figure 11, for two phases, the middle coil of the three coils is connected to the coils on either side of it with the starting end S and ending end E reversed, and for the remaining phase, the coils on either side of the three coils are connected to the coil in between them with the starting end S and ending end E reversed.

[0082] In the case where there are 12 or more coils, i.e., 4 or more sets of coils, the multiple U-phase coils, multiple W-phase coils, and multiple V-phase coils in the multiple sets are each connected in series for each phase and connected to the control driver 600 in a star connection. Moreover, the multiple coils in two phases are connected such that the magnetic poles of the even-numbered sets are opposite to the magnetic poles of the odd-numbered sets, and the multiple coils in the remaining one phase are connected such that the magnetic poles of the odd-numbered sets are opposite to the magnetic poles of the odd-numbered sets of coils in the two phases, and the magnetic poles of the even-numbered sets are opposite to the magnetic poles of the even-numbered sets of coils in the two phases.

[0083] Each of the multiple permanent magnets 522 has a length dimension three times that of the coils of each phase. The multiple permanent magnets 522 are arranged in series along the central axis CA such that adjacent magnetic poles are like and in close contact with each other, as shown in Figure 10. However, a ring-shaped spacer made of a magnetic material, such as an iron plate, may be interposed between adjacent permanent magnets 522 with the same magnetic poles.

[0084] In the stator 510, a plurality of outer electromagnet coils 512 are housed in a cylindrical body 514 having grooves. The cylindrical body 514 is fixed between a first bracket 136 and a second bracket 137.

[0085] Each of the first bracket 136 and the second bracket 138 has a circular opening through which the first movable element 520 can pass. Thus, the first movable element 520 extends in the longitudinal direction X along the central axis CA through the openings of the first bracket 136 and the second bracket 137. In the first movable element 520, a plurality of permanent magnets 522 are housed in a cylindrical case 524. This case 524 extends in the longitudinal direction X along the central axis CA through the openings of the first bracket 136 and the second bracket 137. The case 524 has a front end 5241 in the forward direction X1 (first direction) and a rear end 5242 in the rear direction X2 (second direction). The front end 5241 of the case 524 is held by a first sliding member 151. The rear end 5242 of the case 524 is held by a second sliding member 152. With this configuration, the first movable element 520 is movable in the forward / backward direction X along the central axis CA above the guide rail 150, together with the first and second sliding members 151 and 152.

[0086] The second movable element 530 includes a center core 534 that is movable in the longitudinal direction X along the central axis CA relative to the first movable element 520. The center core 534 is substantially cylindrical in shape. Multiple internal electromagnet coils 532 are mounted around this center core 534. More specifically, the center core 534 consists of a front core portion 5341 on the forward direction X1 (first direction) side, a rear core portion 5342 on the rear direction X2 (second direction) side, and a central core portion 5343 located in the middle between them. A first O-ring 536 is fitted to the center core 534 between the front core portion 5341 and the central core portion 5343. A second O-ring 537 is fitted to the center core 534 between the central core portion 5343 and the rear core portion 5342. Between the first O-ring 536 and the second O-ring 537, multiple internal electromagnet coils 532 are mounted around the center core 534.

[0087] Next, the accessories of the linear motor 500 will be described. The linear motor 500 includes a cylindrical first operating part 560, a columnar second operating part 570, and a stopper 580 as accessories.

[0088] The first operating section 560 is provided on the front surface 151a of the first sliding member 151, extending forward in the first direction X1 (first direction) along the central axis CA. The first operating section 560 includes a cylindrical tubular portion 562 and a cylindrical body 564.

[0089] In the first operating section 560, the cylindrical section 562 has a cylindrical portion 5622, an annular bottom portion 5624, and a gripping portion 5626. The cylindrical portion 5622 extends forward in the first direction X1 along the central axis CA. The annular bottom portion 5624 extends radially outward from the rear end of the cylindrical portion 5622. This annular bottom portion 5624 is fixed to the front surface 151a of the first sliding member 151. The gripping portion 5626 is integrally attached to the front end of the cylindrical portion 5622 and grips the rear end of the cylindrical body 564.

[0090] The cylindrical body 564, gripped by the gripping portion 5626 of the cylindrical portion 562, has a cylindrical shape that extends forward in the first direction X1 along the central axis CA from the cylindrical portion 562. This cylindrical body 564 has an outer diameter smaller than the diameter of the opening 1381 made in another bracket 138. Therefore, the cylindrical body 564 is movable forward in the first direction X1 along the central axis CA through the opening 1381 of the other bracket 138.

[0091] When the cylindrical body 564 moves forward in the first direction X1, its front end (tip) 564a comes into contact with the rear end 432b (see Figure 5) of the rear end 432 of the first movable body 430 of the cartridge injector 400, which is held by the holding block 134. Here, "communication" means contact in a butting state. Then, while in contact, the combination of the first movable body 430 and the second movable body 460 moves forward in the first direction X1 (first direction) along the central axis CA. The cylindrical body 564 has an inner diameter that is slightly larger than the first inner diameter Di2 of the first movable body 430. Therefore, the front end (tip) 564a of the cylindrical body 564 does not come into contact with the rear wall surface 464b (see Figure 6) of the second movable body 460 of the cartridge injector 400.

[0092] A first spring 566 is positioned on the outer circumference of the first operating portion 560. The first spring 566 is positioned between the annular bottom portion 5624 of the cylindrical portion 562 and the cylindrical recess 1382 of another bracket 138. That is, the first spring 566 is positioned between the first sliding member 151 and the other bracket 138. The front end 566a of the first spring 566 contacts the cylindrical recess 1382 of the other bracket 138, and the rear end 566b of the first spring 566 contacts the annular bottom portion 5624 of the cylindrical portion 562.

[0093] Figures 7 to 9 illustrate the linear motor 500 in its initial state. In this initial state, the first spring 566 is not exerting its first biasing force in a substantially nonexistent manner. In this initial state, an external current is applied to the multiple external electromagnet coils 512 of the stator 510. In this case, due to the interaction between the external current and the outer magnetic flux OM of the first movable element 520, the movable elements (520; 530), together with the first and second sliding members 151 and 152, attempt to move forward X1 (first direction) along the central axis CA. Therefore, the first operating part 560 (cylindrical part 562 and cylindrical body 564), which is fixed to the first sliding member 151, moves forward X1 (first direction) along the central axis CA against the first biasing force of the first spring 566.

[0094] When the supply of external current to the coils 512 for the multiple external electromagnets of the stator 510 is stopped, the first thrust (first driving force; first Lorentz force) on the movable elements (520; 530) disappears. Therefore, the first biasing force of the first spring 566 causes the movable elements (520; 530), the first and second sliding members 151 and 152, and the first operating part 560 (cylindrical part 562 and cylindrical body 564) to automatically return to the initial state shown in Figures 7 to 9. Thus, the first spring 566 acts as a first biasing means that biases the movable elements (520; 530) in the rearward direction X2 (second direction).

[0095] The second operating portion 570 consists of a substantially cylindrical rod that extends from the front surface 534a of the center core 534 of the second movable element 530 so as to project forward in the first direction X1 along the central axis CA. The rear end of the second operating portion 570 is fitted into a recess formed in the front core portion 5341 of the center core 534. The second operating portion 570 passes through the cylindrical portion 562 and cylindrical body 564 of the first operating portion 560 without contact (with a gap). The second operating portion 570 has a projection 570a at its front end in the first direction X1.

[0096] As mentioned above, Figures 7 to 9 illustrate the linear motor 500 in its initial state. In this initial state, the projection 570a of the second operating part 570 is substantially at the same position in the front-rear direction X as the front end (tip) 564a of the cylindrical body 564 of the first operating part 560. In this initial state, when the second operating part 570 moves in the forward direction X1 (first direction), the projection 570a of the second operating part 570 comes into contact with the rear wall surface 464b (see Figure 6) of the second movable body 460 of the cartridge injector 400 held by the holding block 134. Then, the second operating part 570 moves the second movable body 460 along the central axis CA in the forward direction X1 (first direction) while in contact with the second movable body 460. The second operating part 570 has a diameter slightly smaller than the second inner diameter Di2 of the first movable body 430. Therefore, the protruding portion 570a of the second operating portion 570 does not come into contact with the rear end 432b (see Figure 5) of the rear end portion 432 of the first movable body 430 of the cartridge injector 400.

[0097] The stopper 580 is fixed to the second sliding member 152 by being fitted into the circular opening of the second sliding member 152. The stopper 580 is cylindrical in shape and extends forward in the first direction X1 along the central axis CA from the second sliding member 152. The rear core portion 5342 of the center core 534 of the second movable element 530 passes through the inside of the stopper 580 with a gap. The second O-ring 537, which is attached to the center core 534, engages with the annular front surface 580a of the stopper 580 in the forward direction X1 (first direction).

[0098] A cylindrical retaining portion 153 is erected in the circular opening of the first sliding member 151, inserted into the inner circumferential wall of the front end portion 5241 of the case 524, and positioned rearward in the second direction X2 along the central axis CA. The inner diameter of the retaining portion 153 is larger than the outer diameter of the center core 534. Therefore, the front core portion 5341 of the center core 534 passes through the retaining portion 153 with a gap between them. A first cap portion 156, having the same inner diameter as the retaining portion 153, is fixed to the rear surface 153b of the retaining portion 153, protruding in the rearward direction X2 (second direction). Therefore, the front core portion 5341 of the center core 534 also passes through this first cap portion 156 with a gap between them. On the other hand, a hollow second cap portion 157 is attached to the first O-ring 536 mounted on the center core 534, protruding in the forward direction X1 (first direction). The inner diameter of the second cap portion 157 may be substantially the same as or slightly larger than the outer diameter of the center core 534. This is because, since the second cap portion 157 is attached to the first O-ring 536, when the center core 534 moves in the forward-backward direction X along the axial direction CA, the second cap portion 157 moves together with the center core 534.

[0099] A second spring 572 is positioned on the outer circumference of the front core portion 5341 of the center core 534. The second spring 572 is positioned between the first cap portion 156 and the second cap portion 157. That is, the second spring 572 is positioned in a space formed on the inner circumference side of the first movable element 520, in a direction X2 (second direction) behind the first sliding member 151. The front end 572a of the second spring 572 contacts the bottom of the first cap portion 156, and the rear end 572b of the second spring 572 contacts the bottom of the second cap portion 157.

[0100] Figures 7 to 9 illustrate the linear motor 500 in its initial state. In this initial state, the second spring 572 is in a state where it does not exert its biasing force substantially. In this initial state, an internal current is passed through the multiple internal electromagnet coils 532 of the second movable element 530. In this case, due to the interaction between the internal current and the inner magnetic flux IM of the first movable element 520, the second movable element 530 attempts to move forward X1 (first direction) along the central axis CA relative to the first movable element 520. Therefore, the second operating part 570, which is fixed to the second movable element 530, moves forward X1 (first direction) along the central axis CA against the biasing force of the second spring 572.

[0101] When the supply of internal current to the multiple internal electromagnet coils 532 of the second movable element 530 is stopped, the second thrust (second driving force; second Lorentz force) on the second movable element 530 disappears. Therefore, the second biasing force of the second spring 572 automatically returns the second movable element 530 and the second operating part 570 to the initial state shown in Figures 7 to 9. Thus, the second spring 572 acts as a second biasing means that biases the second movable element 530 in the rearward direction X2 (second direction).

[0102] Next, the overall operation of the injector module 130 (cartridge injector 400 and linear motor 500) will be described with reference to Figures 4 to 9.

[0103] In the initial state shown in Figures 7 to 9, an external current is passed through the multiple external electromagnet coils 512 of the stator 510 of the linear motor 500 under the control of the controller. As a result, the interaction between this external current and the external magnetic flux OM (see Figure 10) generated by the multiple permanent magnets 522 of the first movable element 520 causes a first thrust (first Lorentz force) to act on the first movable element 520 relative to the stator 510, causing it to move forward X1 (first direction) along the central axis CA. Therefore, this first thrust (first Lorentz force) causes the movable elements (520; 530) to move (travel) forward X1 (first direction) on the guide rail 150 together with the first and second sliding members 151 and 152, against the first biasing force of the first spring 566.

[0104] As the movable elements (520; 530) move forward in the first direction X1, the first operating part 560, which is fixed to the first sliding member 151, also moves forward in the first direction X1 along the central axis CA. As the first operating part 560 moves forward in the first direction X1 along the central axis CA, its front end (tip) 564a engages with the rear end 432b of the first movable body 430 of the cartridge injector 400, causing the first movable body 430 to move forward in the first direction X1 along the central axis CA against the biasing force of the spring 450.

[0105] As a result, the injection needle (catheter) 420 protrudes from the tip 412 of the housing 410 of the cartridge injector 400 through its opening 4121, and the tip 421 of the protruding injection needle (catheter) 420 reaches the muscle of person 200 from the left upper arm 310. This completes the injection needle protrusion step.

[0106] Subsequently, under the control of the controller, an internal current is passed through the multiple internal electromagnet coils 532 of the second movable element 530 of the linear motor 500. As a result, the interaction between this internal current and the internal magnetic flux IM (see Figure 10) generated by the multiple permanent magnets 522 of the first movable element 520 causes a second thrust (second Lorentz force) to act on the second movable element 530 relative to the first movable element 520, causing it to move forward X1 (first direction) along the central axis CA. Thus, this second thrust (second Lorentz force) causes the second movable element 530 to move (travel) forward X1 (first direction) against the second biasing force of the second spring 572.

[0107] As the second movable element 530 moves forward X1 (first direction), the second operating part 570, which is fixed to the tip of the second movable element 530, also moves forward X1 (first direction) along the central axis CA. When the second operating part 570 moves forward X1 (first direction) along the central axis CA, the second operating part 570 moves the second movable body 460 forward X1 (first direction) along the central axis CA, with its protruding part 570a engaging with the rear wall surface 464b of the second movable body 460 of the cartridge injector 400.

[0108] As a result, the housing space AS of the first movable body 430 of the cartridge injector 400 contracts, and the drug solution (liquid) contained in the housing space AS is pushed out through the internal space of the injection needle (catheter) 420 and into the muscle of the person 200 from its tip 421. This completes the drug solution extrusion step.

[0109] After the intramuscular injection is completed in this manner, the flow of the external and internal currents is stopped under the control of the controller. As a result, both the first and second thrusts (first and second Lorentz forces) described above disappear. Consequently, the first biasing force of the first spring 566 of the linear motor 500 biases the movable elements (520; 530) in the rearward direction X2 (second direction) along the central axis CA, and the second movable element 530 is also biased in the rearward direction X2 (second direction) along the central axis CA by the second biasing force of the second spring 572. As a result, the first movable element 520, the first and second sliding members 151 and 152, the first operating part 560, the second movable element 530, and the second operating part 570 all automatically retract in the rearward direction X2 (second direction). This retraction returns the linear motor 500 to its initial state as shown in Figures 7 to 9.

[0110] Simultaneously with the above retraction, the biasing force of the spring 450 of the cartridge injector 400 also biases the first movable body 430 inside the housing 410 in the rearward direction X2 (second direction) along the central axis CA. As a result, the injection needle (catheter) 420 that was protruding to the outside is retracted into the housing 410. This completes the injection needle retraction step.

[0111] As is clear from the above description, according to the embodiment of the present invention, the linear motor 500 is capable of performing a two-stage extension operation that moves two different driven parts (430, 460) of the cartridge injector 400.

[0112] Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments described above. Various modifications to the configuration and details of the present invention can be made that will be understood by those skilled in the art within the scope of the present invention.

[0113] For example, in the linear motor 500 according to the embodiment described above, first and second springs 566 and 572 are used as the first and second biasing means, but of course, other types of biasing means, such as those made of an elastic material exhibiting elasticity like rubber, may also be used. Furthermore, in the embodiment described above, the initial position of the linear motor 500 is defined using a stopper 580. However, instead of using a stopper 580, a position detection mechanism such as an encoder may be provided to define the initial position of the linear motor 500. [Industrial applicability]

[0114] The linear motor according to the present invention is not limited to an external actuator for an injector module, but is also effective as a linear motor that performs a two-stage extension operation to move two different driven objects. [Explanation of Symbols]

[0115] 100 Automatic Vaccine Inoculation Robot Device 110 base 121 First Arm 122 Second Arm 123 Third Arm 124. Fourth Arm 130 Injector Module (Injection Device) 131 First cabinet 132 Second cabinet 133 Base 133a front end 133b rear end 134 Holding Block 136 First bracket 137 Second bracket 138 Another bracket 1381 Aperture 1382 Cylindrical recess 141 First joint 142 Second joint 143 Third joint 144 The fourth joint 150 Guide Rail 150a front end 150b rear end 151 First sliding member 151a Front 152 Second sliding member 153 Holding part 153b Rear 156 First cap portion 157 Second cap section 200 people 210 Left upper arm 300 chairs 400 Cartridge Injector (Simple Syringe) 410 cabinets 411 First Inner Wall 412 Tip 412b rear end 4121 Aperture 413 Rear end 4131 Protrusion 420 Injection needles (catheters) 421 Tip 422 Rear end part 430 First movable body (first driven body) 432 Rear end 432a front end 432b rear end 4321 Exterior wall 4322 Second inner wall 434 Front end 434b Rear wall 4341 Exterior wall 4342 Interior wall 436 Middle section 4361 Exterior wall 4362 Second inner wall 440 Retaining member 450 Spring 451 Front end 451a front end 452 Rear end 452b rear end 460 Second movable body (second driven body) 462 Front component (gasket; packing) 462a Front wall 464 Rear member 464b Rear wall 500 Linear motor (external actuator) 510 Stator 512 Coil for outer electromagnet 514 Cylindrical body 520 First movable element 522 Permanent Magnets 524 cases 5241 Front end 5242 Rear end 530 Second movable element 532 Coil for internal electromagnet 534 Center Core 534a front 5341 Front core section 5342 Rear core section 5343 Central core section 536 First O-ring 537 Second O-ring 560 First operating section 562 Cylindrical part 5622 Cylindrical section 5624 Annular base 5626 Gripping part 564 Cylindrical body 564a Front end (tip) 566 The First Spring 566a front end 566b rear end 570 Second operating section 570a Protrusion 572 The Second Spring 572a front end 572b rear end 580 Stopper 580a Ring Front 600 Control Driver 700 AC power supply Da diameter Di1 First inner diameter Di2 Second inner diameter Di3 Third inner diameter Do1 First outer diameter Do2 Second outer diameter CA center axis AS containment space OM peripheral magnetic flux IM inner magnetic flux

Claims

1. A linear motor comprising a stator and a movable element arranged to be movable along a central axis relative to the stator, wherein the movable element is The first movable element, A second movable element is arranged to be movable along the central axis relative to the first movable element, A linear motor consisting of, Each of the stator, the first movable element, and the second movable element has a shape that is substantially rotationally symmetric with respect to the central axis. The second movable element has a substantially cylindrical shape and is positioned on and near the central axis. The first movable element is substantially cylindrical in shape and is positioned near the outer circumference of the second movable element. The stator is substantially cylindrical in shape and is positioned near the outer circumference of the first movable element. The first movable element has an annular cross-sectional shape and includes a plurality of permanent magnets arranged along the central axis, the plurality of permanent magnets generating outer magnetic flux and inner magnetic flux at their outer and inner circumferences, respectively. The stator includes a plurality of outer electromagnet coils arranged continuously along the central axis so as to surround the first movable element with an outer gap between them, and the interaction between the outer current flowing through the plurality of outer electromagnet coils and the outer magnetic flux allows the stator to move the movable element along the central axis. The second movable element includes a plurality of internal electromagnet coils arranged continuously along the central axis so as to be surrounded by the first movable element, with an internal gap between them, and the interaction between the internal current flowing through the plurality of internal electromagnet coils and the internal magnetic flux allows the second movable element to travel along the central axis relative to the first movable element. Linear motor.

2. The stator includes, as the coils for the plurality of outer electromagnets, a star-connected outer U-phase coil, an outer V-phase coil, and an outer W-phase coil. The second movable element includes, as the plurality of coils for the internal electromagnets, an internal U-phase coil, an internal V-phase coil, and an internal W-phase coil connected in a star configuration. The linear motor consists of a three-phase linear motor. The linear motor according to claim 1.

3. Each of the aforementioned multiple permanent magnets has a length dimension three times that of the coil of each phase. The aforementioned plurality of permanent magnets are arranged in series along the central axis such that adjacent magnetic poles of the same pole are in close contact with each other. The linear motor according to claim 2.

4. The movable element is configured to move in a first direction along the central axis relative to the stator when the external current is passed through the multiple external electromagnet coils of the stator. The second movable element is configured to move in a first direction along the central axis relative to the first movable element when an internal current is passed through the plurality of internal electromagnet coils of the second movable element. The aforementioned linear motor is When the flow of the external current is stopped, a first biasing means biases the movable element in a second direction opposite to the first direction, When the flow of the internal current is stopped, a second biasing means biases the second movable element in the second direction, A linear motor according to any one of claims 1 to 3, further comprising the above.

5. A base arranged parallel to the aforementioned central axis, A guide rail is attached to the base parallel to the central axis, First and second brackets are erected from the base and hold the stator at the end in the first direction and the end in the second direction, respectively. First and second sliding members are provided so as to be slidable on the guide rail and are positioned spaced apart from the first and second brackets in the first and second directions, respectively, and hold the first movable element at both ends thereof. The linear motor according to claim 4, further comprising the above.

6. On the base, another bracket having an opening is erected on the first side of the first bracket, A hollow first operating portion extends from the first sliding member along the central axis in the first direction and is capable of passing through the opening of the other bracket, A second operating part extends from the end of the second movable part in the first direction along the central axis in the first direction and is inserted spaced apart inside the first operating part, The linear motor according to claim 5, further comprising the following:

7. The first biasing means is positioned between the first sliding member and the other bracket, The second biasing means is located on the second side of the first sliding member and in a space formed on the inner circumference side of the first movable element. The linear motor according to claim 6.

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