Pump system, fluid supply device, and pressure detection method

Abstract

The present application provides a pump system, a fluid supply device, and a pressure detection method that can be miniaturized by omitting a pressure sensor and using a pump to detect pressure in a cuff. A pump system (10) includes a vibration driver (8) that is electromagnetically driven, a closed chamber (91) that is connected to a suction port (98) and a discharge port (99), and a movable wall (92) that changes the volume of the closed chamber (91). The movable wall (92) is displaced by driving of the vibration driver (8), and air in the closed chamber (91) is supplied to a cuff (2). Then, the pump system (10) detects pressure in the cuff (2) based on a consumed current of the vibration driver (8).

Description

Technical Field

[0001] This invention relates to pump systems, fluid supply devices, and pressure detection methods. Background Technology

[0002] Patent Document 1, Patent Document 2 and Patent Document 3 respectively describe an electronic blood pressure monitor that measures the blood pressure of a subject, which has a cuff worn on the subject's arm, a pump that increases the pressure inside the cuff by introducing air into the cuff, and a pressure sensor that detects the pressure inside the cuff.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-146894

[0006] Patent Document 2: Japanese Patent Application Publication No. 2014-184071

[0007] Patent Document 3: Japanese Patent Application Publication No. 2017-209433 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Thus, in Patent Document 1, Patent Document 2 and Patent Document 3, the pressure sensor is configured to be independent of the pump phase, resulting in a large number of components and a large device size.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a pump system, a fluid supply device, and a pressure detection method that can be miniaturized by omitting the pressure sensor and using a pump to detect the pressure inside the cuff.

[0011] Solution for solving the problem

[0012] Such an objective is achieved by the present invention described in (1) to (7) below.

[0013] (1) A pump system, characterized in that it comprises:

[0014] Vibration actuator that is driven by electromagnetic force;

[0015] A sealed chamber connected to the inlet and outlet; and

[0016] The movable wall that causes the volume of the aforementioned sealed chamber to change.

[0017] Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object.

[0018] The pressure inside the object is detected based on the current consumed by the aforementioned vibration actuator.

[0019] (2) According to the pump system described in (1) above, the resonant frequency of the vibration driver varies according to the pressure inside the object.

[0020] (3) According to the pump system described in (2) above, the vibration driver has a fluid spring formed by the elastic force of the fluid in the sealed chamber, and the spring constant of the fluid spring varies according to the pressure inside the object, thereby changing the resonant frequency.

[0021] (4) According to the pump system described in (2) or (3) above, as the pressure inside the object increases, the current consumption changes unidirectionally in the direction of decreasing or increasing.

[0022] (5) According to the pump system described in (4) above, the current consumption changes linearly.

[0023] (6) A fluid supply device, characterized in that it comprises a pump system as described in any one of (1) to (5) above.

[0024] (7) A pressure detection method, which is a pressure detection method in a pump system, characterized in that,

[0025] The above pump system has:

[0026] Vibration actuator that is driven by electromagnetic force;

[0027] A sealed chamber connected to the inlet and outlet; and

[0028] The movable wall that causes the volume of the aforementioned sealed chamber to change.

[0029] Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object.

[0030] In the pump system described above, the pressure inside the object is detected based on the current consumed by the vibration actuator.

[0031] The effects of the invention are as follows.

[0032] In the pump system of the present invention, the pressure inside the object is detected based on the current consumed by the electromagnetically driven vibration actuator. Therefore, the pressure inside the object can be detected without using a pressure sensor. Furthermore, the number of parts can be reduced, and the pump system can be miniaturized.

[0033] Furthermore, the fluid supply device of the present invention includes the aforementioned pump system. Therefore, it can enjoy the effects of the pump system and achieve miniaturization of the device.

[0034] Furthermore, in the pressure detection method of the present invention, the pressure inside the object is detected based on the current consumed by the electromagnetically driven vibration actuator. Therefore, the pressure inside the object can be detected without using a pressure sensor. Consequently, the number of components in the pump system can be reduced, and the pump system can be miniaturized. Attached Figure Description

[0035] Figure 1 This is a perspective view showing the overall structure of an electronic blood pressure monitor according to a preferred embodiment.

[0036] Figure 2 This is a cross-sectional view of the pump.

[0037] Figure 3 It is shown Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump.

[0038] Figure 4 It is shown Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump.

[0039] Figure 5 This is a schematic diagram showing the spring system of a vibration actuator.

[0040] Figure 6 It is a graph showing the relationship between the driving frequency of the vibration actuator and the current consumption.

[0041] Figure 7 It is a graph showing the relationship between pressure and current consumption in a sealed chamber.

[0042] Figure 8 It is a graph showing the relationship between pressure and current consumption in a sealed chamber.

[0043] Figure 9 It is a graph showing the relationship between pressure and current consumption in a sealed chamber.

[0044] Figure 10 It is a graph showing the relationship between pressure and current consumption in a sealed chamber.

[0045] Figure 11 It is a graph showing the relationship between pressure and current consumption in a sealed chamber.

[0046] In the picture;

[0047] 1—Electronic blood pressure monitor; 2—Cuff (object); 3—Main body; 4—Tube; 5—Pump; 6—Control device; 7—House; 8—Vibration actuator; 9, 9A, 9B, 9C, 9D—Pump section; 10—Pump system; 61—Drive control section; 62—Pressure detection section; 81—Shaft; 82—Movable body; 83, 84—Magnet; 85, 86—Coil core; 87, 88—Pressing element; 91—Sealed chamber; 92—Movable wall; 93, 94—... 94—Valve, 98—Inlet, 99—Outlet, 831, 841—Magnetic pole face, 851, 861—Magnetic core, 852, 862—Core, 853, 854, 863, 864—Magnetic core poles, 853a, 854a, 863a, 864a—Magnetic pole face, 859, 869—Coil, 921—Insertion part, B1—Magnetic spring, B2—Air spring (fluid spring), B3—Elasticity, F1, F2—Torque. Detailed Implementation

[0048] Hereinafter, the pump system, fluid supply device, and pressure detection method of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0049] Figure 1 This is a perspective view showing the overall structure of an electronic blood pressure monitor according to a preferred embodiment. Figure 2 This is a cross-sectional view of the pump. Figure 3 and Figure 4 They are shown respectively Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump. Figure 5 This is a schematic diagram showing the spring system of a vibration actuator. Figure 6 It is a graph showing the relationship between the driving frequency of the vibration actuator and the current consumption. Figures 7 to 11 These are graphs showing the relationship between pressure and current consumption within a sealed chamber. Furthermore, for ease of explanation, the following will also... Figures 2 to 4 The top side of the paper is called "top", and the bottom side is called "bottom".

[0050] Figure 1 An electronic blood pressure monitor 1, serving as a fluid supply device, is shown. The electronic blood pressure monitor 1 includes a cuff 2, a main body 3, and a supply and exhaust tube 4 connecting the cuff 2 and the main body 3. The cuff 2 is worn on the subject's measurement site, such as the arm. Through fluid supply from the main body 3, an internal pouch expands, compressing the measurement site. The main body 3 measures the pressure within the cuff (object) 2 and calculates the subject's blood pressure based on this measurement. The fluid is not particularly limited; it can be a liquid or a gas, but a gas is preferred. Hereinafter, for ease of explanation, air will be used as the fluid.

[0051] When measuring blood pressure using the conventional oscillometric method, the procedure is as follows: First, a cuff 2 is wrapped around the subject's measurement site. Then, during blood pressure measurement, air is supplied into the cuff 2 from the main body 3, causing the pressure inside the cuff 2 (cuff pressure) to be higher than the highest blood pressure. The pressure is then gradually reduced, and during this process, the pressure inside the cuff 2 is detected by the main body 3, acquiring the change in arterial volume generated at the measurement site as a pulse wave signal. Based on the change in the amplitude of the pulse wave signal accompanying the change in cuff pressure, the highest blood pressure (systolic blood pressure) and the lowest blood pressure (diastolic blood pressure) are calculated, primarily based on the rise and fall. However, there are no particular limitations on the method of blood pressure measurement. For example, the Rivaroć-König method, which is commonly used with the oscillometric method, can also be used.

[0052] like Figure 1 As shown, a pump system 10 is built into the main body 3. This pump system 10 includes a pump 5 that supplies air to the cuff 2, and a control device 6 that controls the drive of the pump 5 and detects the pressure inside the cuff 2. Furthermore, as... Figure 2 As shown, pump 5 has a housing 7, a vibration actuator 8, and a pump section 9.

[0053] The vibration driver 8 has a shaft portion 81, a movable body 82 that is movably supported on the housing 7 via the shaft portion 81, and a pair of coil core portions 85 and 86 fixed to the housing 7.

[0054] The movable body 82 is elongated and connected to the housing 7 via a shaft 81 at its center. Therefore, the movable body 82 rotates back and forth relative to the housing 7 about the shaft 81 like a seesaw.

[0055] Magnets 83 and 84 are provided at both ends of the movable body 82. These magnets 83 and 84 are arranged symmetrically with respect to the shaft portion 81. Furthermore, the magnets 83 and 84 have arc-shaped magnetic pole surfaces 831 and 841 opposite to the coil core portions 85 and 86. On the magnetic pole surfaces 831 and 841, S poles and N poles are alternately arranged along the arc direction. These magnets 83 and 84 are permanent magnets, for example, made of Nd sintered magnets.

[0056] The movable body 82 is provided with pressing members 87 and 88 that press the pump section 9 when the movable body 82 reciprocates. The pressing members 87 and 88 are arranged symmetrically with respect to the shaft portion 81. The pressing member 87 is disposed between the shaft portion 81 and the magnet 83, on both sides in the width direction of the movable body 82. Figure 2 The pressing member 88 protrudes from both sides in the vertical direction. Furthermore, the pressing member 88 is positioned between the shaft portion 81 and the magnet 84, extending to both sides in the width direction of the movable body 82. Figure 2 It protrudes from the top and bottom (both sides).

[0057] The coil cores 85 and 86 are disposed on both sides of the movable body 82. The coil core 85 faces the magnetic pole surface 831 of the magnet 83, and the coil core 86 faces the magnetic pole surface 841 of the magnet 84. The coil cores 85 and 86 are symmetrically arranged with respect to the shaft 81.

[0058] The coil core portion 85 includes a core portion 851 and a coil 859 wound around the core portion 851. The core portion 851 has a core portion 852 around which the coil 859 is wound, and a pair of core magnetic poles 853 and 854 extending from both ends of the core portion 852. The core magnetic poles 853 and 854 have magnetic pole surfaces 853a and 854a opposite to the magnetic pole surface 831 of the magnet 83. The magnetic pole surfaces 853a and 854a are respectively curved in an arc shape, mimicking the magnetic pole surface 831 of the magnet 83. The coil 859 is connected to a control device 6, and is energized with different polarities by power supplied from the control device 6.

[0059] The coil core portion 86 includes a core portion 861 and a coil 869 wound around the core portion 861. The core portion 861 has a core portion 862 on which the coil 869 is wound and a pair of core magnetic poles 863 and 864 extending from both ends of the core portion 862. The core magnetic poles 863 and 864 have magnetic pole surfaces 863a and 864a opposite to the magnetic pole surface 841 of the magnet 84. The magnetic pole surfaces 863a and 864a are respectively curved in an arc shape, mimicking the magnetic pole surface 841 of the magnet 84. The coil 869 is connected to a control device 6, and is energized with different polarities by power supplied from the control device 6.

[0060] The magnetic cores 851 and 861 are magnetic bodies that are magnetized by energizing the coils 859 and 869, respectively, and are made of materials such as electromagnetic stainless steel, sintered materials, MIM (metal injection molding) materials, laminated steel plates, and electro-galvanized steel plates (SECC).

[0061] Four pump units 9 are arranged vertically and horizontally relative to the shaft unit 81. Specifically, two pump units 9 are arranged vertically opposite each other via a pressing member 87 on one side, and the remaining two pump units 9 are arranged vertically opposite each other via a pressing member 88 on the other side. The four pump units 9 have the same structure and each has a sealed chamber 91 and a movable wall 92.

[0062] The sealed chamber 91 is connected to an intake port 98 for drawing in air from the outside and an outlet port 99 for expelling air from the sealed chamber 91. Furthermore, in this embodiment, the two sealed chambers 91 located on the upper side relative to the movable body 82 share a common outlet port 99, and the two sealed chambers 91 located on the lower side relative to the movable body 82 share a common outlet port 99.

[0063] The movable wall 92 forms part of the sealed chamber 91. The movable wall 92 is displaced by being pressed by the pressing members 87 and 88, causing a change in the volume within the sealed chamber 91. If the volume within the sealed chamber 91 decreases due to the displacement of the movable wall 92, air within the sealed chamber 91 is ejected from the outlet 99; conversely, if the volume within the sealed chamber 91 increases, air flows into the sealed chamber 91 from the inlet 98. By repeatedly decreasing and increasing the volume within the sealed chamber 91, air is continuously ejected from the outlet 99. The movable wall 92 is, for example, a diaphragm, formed of a material capable of elastic deformation. Furthermore, the movable wall 92 has an insertion portion 921 for inserting the pressing members 87 and 88, and is connected to the pressing members 87 and 88 via the insertion portion 921.

[0064] Furthermore, a valve 93 is provided between the sealed chamber 91 and the intake port 98. Valve 93 allows air to be drawn into the sealed chamber 91 from the intake port 98, while restricting air from being ejected from the sealed chamber 91 to the intake port 98. Also, a valve 94 is provided between the sealed chamber 91 and the outlet 99. Valve 94 allows air to be ejected from the sealed chamber 91 to the outlet 99, while restricting air from being drawn into the sealed chamber 91 from the outlet 99. This allows for more reliable and efficient air intake and ejection.

[0065] like Figure 1 As shown, the control device 6 includes a drive control unit 61 for controlling the drive of the vibration driver 8 and a pressure detection unit 62 for detecting the pressure inside the cuff 2. The control device 6 is, for example, a computer, and includes a processor (CPU) for processing information, a memory connected to the processor in a communicative manner, and an external interface. Furthermore, various programs executable by the processor are stored in the memory, and the processor reads and executes these programs.

[0066] The structure of the electronic blood pressure monitor 1 has been described above. Next, the operation of the pump 5 will be explained. Furthermore, for ease of explanation, the four pump sections 9 will be referred to as "Pump Section 9A", "Pump Section 9B", "Pump Section 9C" and "Pump Section 9D" for distinction.

[0067] If an AC voltage is applied to coils 859 and 869 from the drive control unit 61, pump 5 repeatedly drives between the first state and the second state. The first state is as follows: Figure 3 The movable body 82 shown is in a state of rotation to one side, and the second state is as follows: Figure 4 The movable body 82 shown is rotated to the other side. Figure 3 In the first state shown, magnetic core poles 853 and 864 are energized as N poles, and magnetic core poles 854 and 863 are energized as S poles. Conversely, in... Figure 4In the second state shown, magnetic core poles 853 and 864 are energized as S poles, and magnetic core poles 854 and 863 are energized as N poles.

[0068] In the first state, the magnetic force (attraction and repulsion) acting between magnets 83 and 84 and coil cores 85 and 86 generates a torque F1 in the direction of the arrow, causing the movable body 82 to rotate in the direction of the torque F1. Consequently, in pump sections 9A and 9D, the movable wall 92 is pressed by pressing members 87 and 88, reducing the volume within the sealed chamber 91, and air within the sealed chamber 91 is ejected from the nozzle 99. The ejected air is then supplied to the cuff 2 via pipe 4, increasing the pressure within the cuff 2. Conversely, in pump sections 9B and 9C, the volume within the sealed chamber 91 increases, and air flows into the sealed chamber 91 from the inlet 98.

[0069] In the second state, the magnetic force (attraction and repulsion) acting between magnets 83 and 84 and coil cores 85 and 86 generates a torque F2 opposite to the direction of torque F1, causing the movable body 82 to rotate in the direction of torque F2. Consequently, in pump sections 9B and 9C, the movable wall 92 is pressed by pressing members 87 and 88, reducing the volume within the sealed chamber 91, and air within the sealed chamber 91 is ejected from the nozzle 99. The ejected air is then supplied to the cuff 2 via pipe 4, increasing the pressure within the cuff 2. Conversely, in pump sections 9A and 9D, the volume within the sealed chamber 91 increases, and air flows into the sealed chamber 91 from the inlet 98.

[0070] In this way, by alternately repeating the first and second states, the states of air being ejected from pump sections 9A and 9D and the states of air being ejected from pump sections 9B and 9C are alternately repeated, thereby continuously ejecting air from pump 5. Therefore, air can be efficiently supplied to cuff 2, and the pressure inside cuff 2 can be smoothly increased.

[0071] The driving mechanism of pump 5 has been explained above. Next, the driving principle of pump 5 will be explained. The vibration actuator 8 is driven based on the motion equation shown in equation (1) and the circuit equation shown in equation (2).

[0072] [Formula 1]

[0073]

[0074] J: Torque of inertia [kg·m] 2 ]

[0075] θ(t): Displacement angle [rad]

[0076] K t Torque constant [Nm / A]

[0077] i(t): Current [A]

[0078] K sp Spring constant [N / m]

[0079] D: Attenuation coefficient [Nm / (rad / s)]

[0080] [Equation 2]

[0081]

[0082] e(t): Voltage [V]

[0083] R: Resistance [Ω]

[0084] L: Inductance [H]

[0085] K e Back electromotive force constant [V / (m / s)]

[0086] Thus, the inertial torque J[Kg·m] of the movable body 82 2 Displacement angle (rotation angle) θ(t) [rad], torque constant K t [Nm / A], current i(t) [A], spring constant K sp The values ​​of [Nm / rad] and attenuation coefficient D [Nm / (rad / s)] can be appropriately set within the range satisfying equation (1). Similarly, the voltage e(t) [V], resistance R [Ω], inductance L [H], and back electromotive force constant K can be set appropriately. e [V / (m / s)] can be appropriately set within the range that satisfies equation (2).

[0087] Furthermore, in pump 5, the flow rate is set according to the following formula (3), and the pressure is set according to the following formula (4).

[0088] [Formula 3]

[0089] Q = Axf * 60 - (3)

[0090] Q: Flow rate [L / min]

[0091] A: Piston area [m] 2 ]

[0092] x: Piston displacement [m]

[0093] f: Drive frequency [Hz]

[0094] [Formula 4]

[0095]

[0096] P: Increased pressure [kPa]

[0097] P0: Atmospheric pressure [kPa]

[0098] V: Volume of the sealed chamber [m] 3 ]

[0099] ΔV: Variable volume [m] 3 ]

[0100] ΔV=Ax

[0101] A: Piston area [m] 2 ]

[0102] x: Piston displacement [m]

[0103] Thus, the flow rate Q [L / min] and piston area A [m²] of pump 5 are... 2 The piston displacement x [m], driving frequency f [Hz], etc., can be appropriately set within the range that satisfies equation (3). Similarly, the pressure P [kPa], atmospheric pressure P0 [kPa], and sealed chamber volume V [m] can be increased. 3 ]、Variable volume ΔV[m 3 The parameters can be appropriately set within the range that satisfies equation (4).

[0104] Next, the resonant frequency of the vibration actuator 8 will be explained. For example... Figure 5 As shown, the vibration actuator 8 has a spring-mass system structure that uses a magnetic spring B1 and an air spring (fluid spring) B2 to support the movable body 82. The magnetic spring B1 is formed by the magnetic force acting between the coil cores 85 and 86 and the magnets 83 and 84, while the air spring B2 is formed by the elastic force of compressed air within the sealed chamber 91. Therefore, the movable body 82 has a resonant frequency f as shown in equation (5). r .

[0105] [Formula 5]

[0106]

[0107] f r Resonant frequency [Hz]

[0108] K sp Spring constant [N / m]

[0109] J: Torque of inertia [kg·m] 2 ]

[0110] Furthermore, as shown in equation (6) below, the spring constant K sp The spring constant K of the vibration actuator 8, including the magnetic spring B1 and the elasticity B3 of the movable wall 92, is itself. ACT With respect to the spring constant K of air spring B2 Air The sum is represented by .

[0111] [Formula 6]

[0112] K sp =K ACT +K Air -(6)

[0113] K ACT The spring constant of the vibration actuator itself

[0114] K Air The spring constant of an air spring

[0115] From equations (5) and (6) above, it can be seen that in the vibration actuator 8, the spring constant K of the air spring B2 is... Air The resonant frequency f of the movable body 82 varies depending on the pressure within the sealed chamber 91 (the pressure within the cuff 2). r Changes. Therefore, in pump system 10, attention is focused on the resonant frequency f that accompanies this change. r The change in the power consumption of the vibration actuator 8 caused by the change in the current consumption is used to detect the pressure inside the sealed chamber 91.

[0116] Next, the power-consuming pressure detection method based on the vibration actuator 8 will be specifically described. Furthermore, for ease of explanation, the pump 5, capable of raising the pressure within the cuff 2 to a maximum of 50 kPa, will be used as an example. However, there is no particular limitation on the maximum pressure; it can be appropriately set in a manner that meets the required conditions. And, as mentioned above, since the cuff 2 and the sealed chamber 91 are connected via the pipe 4, they have the same pressure. Therefore, "pressure within the sealed chamber 91" and "pressure within the cuff 2" have the same meaning.

[0117] Figure 6 The relationship between the driving frequency f and the current consumption of the vibration actuator 8 when the pressure inside the cuff 2 is 0 kPa to 50 kPa is shown. The current consumption of the vibration actuator 8 refers to the current flowing inside the main circuit of the vibration actuator 8, primarily the current flowing in the circuit used to supply current to coils 859 and 869. Furthermore, the alternating voltage applied to coils 859 and 869 is constant. Figure 6 The relationship shown is an example, and the present invention is not limited to this relationship.

[0118] Figure 6 In the context of various pressures, the driving frequency fmin and the resonant frequency fmin are found to be the lowest current consumption. r Broadly the same. Therefore, from Figure 6 It can be seen that as the pressure inside the cuff 2 increases, the spring constant K of the air spring B2 also increases. Air Increase, resonant frequency f r It gets taller.

[0119] Here, Figure 6 In the pump 5, within the range of drive frequency f from fmin to fmax, the current consumption of the vibration actuator 8 decreases as the pressure inside the cuff 2 increases. That is, as the pressure inside the cuff 2 increases, the current consumption changes unidirectionally (towards either decreasing or increasing). The drive frequency f is set within the range of fmin to fmax, where the current consumption changes unidirectionally as the pressure inside the cuff 2 increases. Furthermore, the drive frequency f can be fixed at an initial value and cannot be changed, or it can be appropriately set by the user within the range of fmin to fmax. For ease of explanation, the following description will take the case where the drive frequency f is fixed at fn as an example.

[0120] Figure 7 The figure shows the relationship between the pressure inside the sealed chamber 91 and the current consumption of the vibration actuator 8 at the driving frequency f = fn. As shown in the figure, at the driving frequency f = fn, the current consumption of the vibration actuator 8 decreases linearly as the pressure inside the cuff 2 increases.

[0121] In the pressure detection unit 62 of the control device 6, the relationship between the pressure inside the cuff 2 and the current consumed by the vibration actuator 8 at the drive frequency f = fn is stored in advance in the form of tables and calculation formulas. Then, the pressure detection unit 62 detects the current consumed by the vibration actuator 8 and applies the detected current consumed to the tables and functions to calculate the pressure inside the cuff 2. In particular, in this embodiment, since the current consumed by the vibration actuator 8 decreases linearly, the degree of change of the current consumed relative to the pressure inside the cuff 2 is approximately uniform and sufficiently large throughout the entire pressure range of 0 kPa to 50 kPa. Therefore, the pressure inside the cuff 2 can be detected with high accuracy throughout the entire pressure range.

[0122] Thus, according to the pump system 10, the pressure inside the cuff 2 can be effectively detected by utilizing the characteristics of the pump 5 itself without using a pressure sensor. Therefore, it is unnecessary to have a pressure sensor or other components for detecting the pressure inside the cuff 2, which are separate from the pump 5, as is the case in existing technologies. Therefore, the number of components in the pump system 10 is reduced, enabling miniaturization of the pump system 10. In particular, the vibration actuator 8 has a resonant frequency f. r Based on the characteristic that the current consumption of the vibration actuator 8 varies with the pressure within the cuff 2, it is easy to assign this characteristic to the vibration actuator 8 so that the current consumption varies with the pressure within the cuff 2. Furthermore, the vibration actuator 8 has an air spring B2, thereby enabling the vibration actuator 8 to be assigned a resonant frequency f with a simple structure. r The characteristic that varies depending on the pressure inside the cuff 2.

[0123] Furthermore, there are no particular limitations on the method for setting the driving frequency f; for example, it can be set as follows: The closer the driving frequency f is to the resonant frequency f...r The larger the amplitude of the vibration actuator 3, the higher the airflow Q from the pump 5. Furthermore, the closer the driving frequency f is to the resonant frequency f... r The greater the difference between the current consumed by the vibration actuator 8 at 0 kPa and the current consumed by the vibration actuator 8 at 50 kPa, the greater the change in current consumption relative to the pressure inside the cuff 2, thus enabling higher precision detection of the pressure inside the cuff 2.

[0124] Therefore, it is preferable to use the resonant frequency f at 0 kPa. r The resonant frequency f at 50 kPa r The frequency at which the difference between the current consumption at 0 kPa and the current consumption at 50 kPa is greatest, or near it (e.g., within 90% of the maximum value), is set as the driving frequency f. Based on this driving frequency f, the pump 5 can be driven effectively while simultaneously detecting the pressure within the cuff 2 with higher accuracy. For this reason, in this embodiment, the resonant frequency f at 0 kPa is used. r The resonant frequency f at 50 kPa r The frequency fn, which is the position where the difference between the current consumption at 0 kPa and the current consumption at 50 kPa is the largest, is set as the driving frequency f.

[0125] also, Figure 7 In this process, as the pressure inside the cuff 2 increases, the current consumption of the vibration actuator 8 decreases linearly, but this is not limited to this; for example, it can also be as follows: Figure 8 The decrease is non-linear. In this case, in the region of low pressure within the cuff 2, the change in current consumption relative to pressure is larger, thus enabling higher accuracy in detecting the pressure within the cuff 2. On the other hand, in the region of high pressure within the cuff 2, the change in current consumption relative to pressure tends to be smaller, potentially making it impossible to detect the pressure within the cuff 2 with sufficient accuracy. In this respect, Figure 7 The line shape shown is superior.

[0126] and, Figure 7 In this process, as the pressure inside the cuff 2 increases, the current consumption of the vibration actuator 8 changes unidirectionally in the decreasing direction, but it is not limited to this. For example, it can also be as follows: Figure 9 As shown, as the pressure inside the cuff 2 increases, the current consumed by the vibration actuator 8 changes unidirectionally in the increasing direction. Under such circumstances, it is also related to... Figure 7 Similarly, throughout the entire pressure region, the degree of change in current consumption relative to the pressure within cuff 2 becomes sufficiently large. Therefore, it is possible to detect the pressure within cuff 2 with high accuracy throughout the entire pressure region.

[0127] and, Figure 7 In this process, as the pressure inside the cuff 2 increases, the current consumption of the vibration actuator 8 changes unidirectionally in the decreasing direction, but it is not limited to this. For example, it can be as follows: Figure 10 As shown, the decrease turns into an increase, or it can be like... Figure 11 As shown, the current decreases after an increase. However, in this case, sometimes the same current consumption is observed at different pressures on both sides of the extreme value, so it is necessary to find a way to distinguish them. For example, continuously monitor the current consumption from a sufficiently low pressure state to determine whether the extreme value has been exceeded (at... Figure 10 The mean is the minimum value, in Figure 11 (The maximum value is in the middle), which allows us to determine whether the pressure is on the side lower than the extreme value or on the side higher than the extreme value.

[0128] Furthermore, the above description explains the case where the drive frequency f is fixed as fn. However, if the user can appropriately select the drive frequency f from multiple values, the pressure detection unit 62 can store the relationship between the pressure inside the cuff 2 and the current consumption in advance in the form of tables or functions for each selectable drive frequency f. The pressure inside the cuff 2 can be calculated using the table or function corresponding to the selected drive frequency f.

[0129] The pump system, fluid supply device, and pressure detection method of the present invention have been described above based on the illustrated embodiments. However, the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. Furthermore, other arbitrary components can be added to the present invention.

[0130] Furthermore, for example, in the above embodiment, the pump system and fluid supply device are applied to the electronic blood pressure monitor 1, but it is not limited thereto, and can be applied to any device that requires fluid supply. Also, for example, in the above embodiment, the pump 5 has four pump sections 9, but it is not limited thereto, as long as it has at least one pump section 9.

[0131] Furthermore, the structure of the vibration actuator 8 is not particularly limited as long as it consumes current that varies according to the pressure inside the sealed chamber 91. For example, in the above embodiment, magnets 83 and 84 are provided in the movable body 82, and coil cores 85 and 86 are provided in the housing 7, but this is not a limitation, and the reverse is also possible. That is, coil cores 85 and 86 may be provided in the movable body 82, and magnets 83 and 84 may be provided in the housing 7. Furthermore, magnets 83 and 84 may be replaced with electromagnets.

Claims

1. A pump system, characterized in that, have: Vibration actuator that is driven by electromagnetic force; A sealed chamber connected to the inlet and outlet; Movable walls that cause changes in the volume of the aforementioned sealed chamber; and The housing contains the aforementioned vibration actuator, the aforementioned sealed chamber, and the aforementioned movable wall. The aforementioned vibration actuator includes a shaft portion disposed in the aforementioned housing, a movable body supported by the aforementioned shaft portion to enable the movable wall to reciprocate relative to the aforementioned housing, a pair of coil magnetic core portions fixed to one of the aforementioned housing and the aforementioned movable body, and a pair of magnets disposed on the other of the aforementioned housing or the aforementioned movable body to respectively face the aforementioned coil magnetic core portions. The aforementioned vibration actuator has a spring-mass system structure supporting the movable body. This spring-mass system structure comprises a magnetic spring and a fluid spring. The magnetic spring is formed by the magnetic force acting between the coil core and the magnet, while the fluid spring is formed by the elastic force of the compressed fluid within the sealed chamber. Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object. The pressure inside the object is detected based on the current consumed by the aforementioned vibration actuator. The driving frequency of the aforementioned vibration actuator is set to a region in which the current consumption changes unidirectionally as the pressure inside the object increases.

2. The pump system according to claim 1, characterized in that, The resonant frequency of the aforementioned vibration actuator varies depending on the pressure within the aforementioned object.

3. The pump system according to claim 2, characterized in that, The spring constant of the fluid spring varies according to the pressure inside the object, thereby changing the resonant frequency.

4. The pump system according to claim 2 or 3, characterized in that, As the pressure inside the object increases, the current consumption changes unidirectionally in either the decreasing or increasing direction.

5. The pump system according to claim 4, characterized in that, The aforementioned current consumption varies linearly.

6. A fluid supply device, characterized in that, The pump system described in any one of claims 1 to 5 is provided.

7. A pressure detection method, which is a pressure detection method in a pump system, characterized in that, The above pump system has: Vibration actuator that is driven by electromagnetic force; A sealed chamber connected to the inlet and outlet; Movable walls that cause changes in the volume of the aforementioned sealed chamber; and The housing contains the aforementioned vibration actuator, the aforementioned sealed chamber, and the aforementioned movable wall. The aforementioned vibration actuator includes a shaft portion disposed in the aforementioned housing, a movable body supported by the aforementioned shaft portion to enable the movable wall to reciprocate relative to the aforementioned housing, a pair of coil magnetic core portions fixed to one of the aforementioned housing and the aforementioned movable body, and a pair of magnets disposed on the other of the aforementioned housing or the aforementioned movable body to respectively face the aforementioned coil magnetic core portions. The aforementioned vibration actuator has a spring-mass system structure supporting the movable body. This spring-mass system structure comprises a magnetic spring and a fluid spring. The magnetic spring is formed by the magnetic force acting between the coil core and the magnet, while the fluid spring is formed by the elastic force of the compressed fluid within the sealed chamber. Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object. In the aforementioned pump system, the pressure inside the object is detected based on the current consumed by the aforementioned vibration actuator. The driving frequency of the aforementioned vibration actuator is set in a region where the current consumption changes unidirectionally as the internal pressure of the object increases.

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