Pump system, fluid supply device, and drive control method for pump system

Abstract

The present application provides a pump system, a fluid supply device, and a driving control method of the pump system, which can exhibit excellent flow characteristics with a simple structure. A pump system (10) includes a vibration driver (8) that is electromagnetically driven by applying an alternating voltage (E), a closed chamber (91) 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). Furthermore, by driving the vibration driver (8), the movable wall (92) is displaced, and a fluid in the closed chamber (91) is supplied to an object. In such a pump system (10), the effective value of the alternating voltage (E) is controlled in such a manner that the amplitude (Y) of the vibration driver (8) becomes constant.

Description

Technical Field

[0001] This invention relates to pump systems, fluid supply devices, and drive control methods for pump systems. Background Technology

[0002] For example, in the water supply device described in Patent Document 1, since the optimal speed of the motor pump varies depending on the pressure, the voltage supplied to the motor pump is adjusted to achieve the optimal speed relative to each pressure. Furthermore, in the pump control device described in Patent Document 2, the necessary speed required to obtain the desired flow rate is predicted based on prior pump performance measurements and pump performance measurements under piping or other conditions, and the voltage required to achieve the predicted necessary speed is calculated and output. Moreover, in the pump unit described in Patent Document 3, two pump sections with different volumes are provided so that high pressure and high flow rate can be respectively handled in a small motor, and the pump sections can be switched according to the pressure status.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-031078

[0006] Patent Document 2: Japanese Patent Application Publication No. 2001-342966

[0007] Patent Document 3: Japanese Patent Application Publication No. 2004-011597 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in Patent Document 1, since the motor speed varies depending on the voltage, it is necessary to address the abnormal noises and malfunctions caused by resonance phenomena resulting from the speed variation. Therefore, the device structure becomes complex. Furthermore, in Patent Document 2, multiple calculations are required to calculate and output the required voltage. Therefore, the device structure, especially the circuit structure, becomes cumbersome. Moreover, in Patent Document 3, multiple pump units and mechanisms for switching between these pump units are required. Therefore, the device becomes large and its structure becomes complex.

[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 drive control method for the pump system that can achieve excellent flow characteristics with a simple structure.

[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] A vibration actuator that is electromagnetically driven by applying alternating voltage;

[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 effective value of the alternating voltage is controlled in a way that makes the amplitude of the vibration driver constant.

[0019] (2) According to the pump system described in (1) above, the effective value is controlled by changing the amplitude of the alternating voltage.

[0020] (3) According to the pump system described in (1) above, the alternating voltage is a rectangular wave.

[0021] The effective value is controlled by changing at least one of the amplitude and duty cycle of the alternating voltage.

[0022] (4) According to the pump system described in any one of (1) to (3) above, the pressure inside the object is detected, and the effective value is controlled based on the detected pressure.

[0023] (5) According to any one of (1) to (4) above, the resonant frequency of the vibration actuator varies according to the pressure inside the object.

[0024] (6) A fluid supply device, characterized in that it comprises a pump system as described in any one of (1) to (5) above.

[0025] (7) A method for driving and controlling a pump system, the pump system comprising:

[0026] A vibration actuator that is electromagnetically driven by applying alternating voltage;

[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] The characteristic of the above-mentioned pump system drive control method is that,

[0031] The effective value of the alternating voltage is controlled in a way that makes the amplitude of the vibration driver constant.

[0032] The effects of the invention are as follows.

[0033] In the pump system of the present invention, the effective value of the alternating voltage is controlled in a manner that keeps the amplitude of the vibration actuator constant. Therefore, it is possible to prevent the decrease in amplitude caused by an increase in pressure within the object, resulting in a pump system capable of exhibiting excellent flow characteristics.

[0034] 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 become a fluid supply device capable of exhibiting excellent flow characteristics.

[0035] In the pump system drive control method of the present invention, the effective value of the alternating voltage is controlled in a manner that keeps the amplitude of the vibration actuator constant. Therefore, it is possible to prevent the amplitude from decreasing due to an increase in pressure within the object, thereby enabling the pump system to exhibit excellent flow characteristics. Attached Figure Description

[0036] Figure 1 This is a perspective view showing the overall structure of an electronic blood pressure monitor according to a preferred embodiment.

[0037] Figure 2 This is a cross-sectional view of the pump.

[0038] Figure 3 It is shown Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump.

[0039] Figure 4 It is shown Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump.

[0040] Figure 5 This is a schematic diagram showing the spring system of a vibration actuator.

[0041] Figure 6 It is a graph showing the relationship between the driving frequency and the amplitude.

[0042] Figure 7 It is a graph showing the relationship between drive frequency and flow rate.

[0043] Figure 8 It is a graph showing the relationship between pressure and amplitude inside a sealed chamber.

[0044] Figure 9 It is a graph showing the relationship between pressure and flow rate in a sealed chamber.

[0045] Figure 10 It is a graph showing the relationship between pressure and amplitude inside a sealed chamber.

[0046] Figure 11 It is a graph showing the relationship between pressure and flow rate in a sealed chamber.

[0047] Figure 12 This is a diagram showing an example of the waveform of an alternating voltage.

[0048] Figure 13 This is a diagram showing an example of the waveform of an alternating voltage.

[0049] Figure 14 This is a diagram showing an example of the waveform of an alternating voltage.

[0050] Figure 15 This is a diagram showing an example of the waveform of an alternating voltage.

[0051] In the picture:

[0052] 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—Valve; 98—Inlet; 99—Outlet; 100—Pressure sensor 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; E—Alternating voltage; Emax—Maximum voltage value; F1, F2—Torque; Q—Flow rate; Y—Amplitude; Yt—Target amplitude; f—Drive frequency. Detailed Implementation

[0053] Hereinafter, based on the preferred embodiments shown in the accompanying drawings, the pump system, fluid supply device, and pump system drive control method of the present invention will be described in detail.

[0054] 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 It is shown Figure 2 The diagram shows a cross-sectional view illustrating the driving principle of the pump. Figure 4 It is shown 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 6It is a graph showing the relationship between the driving frequency and the amplitude. Figure 7 It is a graph showing the relationship between drive frequency and flow rate. Figure 8 It is a graph showing the relationship between pressure and amplitude inside a sealed chamber. Figure 9 It is a graph showing the relationship between pressure and flow rate in a sealed chamber. Figure 10 It is a graph showing the relationship between pressure and amplitude inside a sealed chamber. Figure 11 It is a graph showing the relationship between pressure and flow rate in a sealed chamber. Figures 12 to 15 These are diagrams illustrating an example of the waveform of an alternating voltage. 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".

[0055] 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 2 (the object) 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.

[0056] 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, during which the main body 3 detects the pressure inside the cuff 2, 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.

[0057] like Figure 1 As shown, the main body 3 is provided with a pressure sensor 100 for detecting the pressure inside the cuff 2. Furthermore, the main body 3 is provided with a pump system 10, which includes a pump 5 for supplying air to the cuff 2 and a control device 6. The control device 6 detects the pressure inside the cuff 2 based on the output signal from the pressure sensor 100 and controls the drive of the pump 5 based on the detected pressure inside the cuff 2.

[0058] like Figure 2As shown, pump 5 has a housing 7, a vibration actuator 8, and a pump section 9.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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).

[0063] 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.

[0064] 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 the core magnetic poles 853 and 854 are energized by applying an alternating voltage E from the control device 6.

[0065] 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 around 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 the core magnetic poles 863 and 864 are energized by applying an alternating voltage E from the control device 6.

[0066] 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).

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] like Figure 1 As shown, the control device 6 includes: a pressure detection unit 62, which detects the pressure inside the cuff 2 based on the output signal of the pressure sensor 100; and a drive control unit 61, which controls the drive of the vibration driver 8 based on the pressure inside the cuff 2 detected by the pressure detection unit 62. Such a control device 6 is, for example, a computer, having 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.

[0072] 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.

[0073] If an AC voltage E is applied from the drive control unit 61 to the coils 859 and 869, the 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 4 In 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.

[0074] 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.

[0075] 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.

[0076] 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 rise smoothly.

[0077] 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).

[0078] [Formula 1]

[0079]

[0080] J: Torque of inertia [kg·m] 2 ]

[0081] θ(t): Displacement angle [rad]

[0082] K t Torque constant [Nm / A]

[0083] i(t): Current [A]

[0084] K sp Spring constant [N / m]

[0085] D: Attenuation coefficient [Nm / (rad / s)]

[0086] [Equation 2]

[0087]

[0088] e(t): Voltage [V]

[0089] R: Resistance [Ω]

[0090] L: Inductance [H]

[0091] K e Back electromotive force constant [V / (m / s)]

[0092] 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).

[0093] 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).

[0094] [Formula 3]

[0095] Q = Axf * 60 - (3)

[0096] Q: Flow rate [L / min]

[0097] A: Piston area [m] 2 ]

[0098] x: Piston displacement [m]

[0099] f: Drive frequency [Hz]

[0100] [Formula 4]

[0101]

[0102] P: Increased pressure [kPa]

[0103] P0: Atmospheric pressure [kPa]

[0104] V: Volume of the sealed chamber [m] 3 ]

[0105] ΔV: Variable volume [m] 3 ]

[0106] ΔV=Ax

[0107] A: Piston area [m] 2 ]

[0108] x: Piston displacement [m]

[0109] 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 satisfying equation (3). Furthermore, the pressure [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).

[0110] 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 .

[0111] [Formula 5]

[0112]

[0113] f r Resonant frequency [Hz]

[0114] K sp Spring constant [N / m]

[0115] J: Torque of inertia [kg·m] 2 ]

[0116] 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 .

[0117] [Formula 6]

[0118] K sp =K ACT +KAir -(6)

[0119] K ACT The spring constant of the vibration actuator itself

[0120] K Air The spring constant of an air spring

[0121] 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 change.

[0122] Next, the resonance frequency f r The changes in the amplitude Y of the vibration actuator 8 and the flow rate Q of the air ejected from the pump 5 will be explained. Furthermore, for ease of explanation, the pump 5, which can raise the pressure inside the cuff 2 to a maximum of 50 kPa, will be used as an example in the following description. However, there is no particular limitation on the maximum pressure, and 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 inside the sealed chamber 91" and "pressure inside the cuff 2" have the same meaning.

[0123] Figure 6 The relationship between the driving frequency f and the amplitude Y is shown when the pressure inside the cuff 2 is between 0 kPa and 50 kPa. Furthermore, Figure 7 The relationship between the drive frequency f and the flow rate Q is shown when the pressure inside the cuff 2 is between 0 kPa and 50 kPa. Furthermore, the drive frequency f is the frequency of the alternating voltage E. Figure 6 and Figure 7 In this process, the voltage value and waveform of the alternating voltage E are constant, and only the driving frequency f changes. Figure 6 In the middle, the driving frequency f with the largest amplitude Y and the resonant frequency f r They are largely the same. Furthermore, Figure 7 In the middle, the driving frequency f with the maximum flow rate Q is equal to the resonant frequency f. r They are largely the same. Thus, from... Figure 6 and Figure 7 It can also be seen that the resonant frequency f r It varies depending on the pressure inside the cuff 2. However, Figure 6 and Figure 7 The relationship shown is an example, and the present invention is not limited to this relationship.

[0124] Figure 8 The relationship between the internal pressure of the sealed chamber 91 and the amplitude Y is shown when the driving frequency f = fn. Furthermore, Figure 9The relationship between the internal pressure and flow rate Q of the sealed chamber 91 at the driving frequency f = fn is shown. From Figure 8 and Figure 9 It can be seen that the amplitude Y varies according to the pressure within the cuff 2, and consequently, the flow rate Q varies. Specifically, it can be seen that the higher the pressure within the cuff 2, the lower the amplitude Y, and consequently, the lower the flow rate Q. This means that at the resonant frequency f... r As the pressure inside the cuff increases, the driving frequency f approaches the resonant frequency f. r The larger the amplitude Y, the higher the flow rate Q; conversely, the further the driving frequency f is from the resonant frequency fresonant. r If the amplitude Y is smaller, the flow rate Q will be lower.

[0125] Thus, if the flow rate Q decreases as the pressure inside the cuff 2 increases, the flow rate Q becomes unstable, and a sufficient amount of air cannot be supplied to the cuff 2 in the high-pressure region. Therefore, the pressure inside the cuff 2 cannot rise smoothly. Thus, a pump 5 with excellent flow characteristics cannot be achieved by applying a constant alternating voltage E regardless of the pressure inside the cuff 2.

[0126] In contrast, if the amplitude Y can be suppressed from decreasing as the pressure inside the cuff 2 increases, and the vibration actuator 8 is maintained with a sufficiently large amplitude Y throughout the range of 0 kPa to 50 kPa, then the aforementioned decrease in flow rate Q can be suppressed, the flow rate Q is stabilized, and a sufficient amount of air can be supplied to the cuff 2 even in high-pressure regions. Therefore, in this embodiment, the effective value of the alternating voltage E is controlled in a manner that maintains a sufficiently large amplitude Y throughout the entire range of 0 kPa to 50 kPa. This will be explained below.

[0127] First, as a premise, the driving frequency f is constant in the driving of pump 5. The driving frequency f is not particularly limited, and can be determined, for example, as follows: The closer the driving frequency f is to the resonant frequency f... r The larger the amplitude Y, the higher the flow rate Q. Additionally, the closer the driving frequency f is to the resonant frequency f... r The closer the vibration actuator is to resonance, the more energy-efficient the vibration actuator 8 can achieve. Therefore, it is preferable to use a frequency between 0 kPa and 50 kPa and the resonance frequency f. r The frequency between the minimum and maximum values ​​is set as the driving frequency f. That is, in Figure 6 and Figure 7 In the example shown, the resonant frequency f at 0 kPa is preferred. r The resonant frequency f at 50 kPa r The frequency between these two points is set as the driving frequency f. Therefore, it is possible to control the driving frequency f and the resonant frequency f within the range of 0 kPa to 50 kPa. rThe difference is suppressed relatively small, making it easy to achieve the above-mentioned effect. For this reason, in the above explanation, the driving frequency is set as f = fn.

[0128] The drive control unit 61 stores a target amplitude Yt, which is the target value of the amplitude Y. The target amplitude Yt is not particularly limited; the larger the better. By setting the target amplitude Yt as large as possible, a larger flow rate Q is achieved, thereby improving the flow characteristics of the pump 5. The target amplitude Yt is set, for example, to have a margin relative to the maximum amplitude that can be generated by the vibration actuator 8 to avoid risks such as malfunctions; for example, it can be set to approximately 80% to 95% of the maximum amplitude. This ensures the lifespan and long-term reliability of the pump 5, and allows the pump 5 to fully utilize its force.

[0129] Furthermore, the drive control unit 61 has a control program for maintaining the amplitude Y at a target amplitude Yt between 0 kPa and 50 kPa. This control program is not particularly limited; examples include tables that correlate the pressure within the cuff 2 with the effective value of the alternating voltage E used to make the amplitude Y reach the target amplitude Yt at that pressure, and formulas that calculate the effective value of the alternating voltage E used to make the amplitude Y reach the target amplitude Yt at that pressure when the pressure within the cuff 2 is substituted.

[0130] The drive control unit 61 calculates the effective value of the alternating voltage E corresponding to the pressure inside the cuff 2 detected by the pressure detection unit 62 according to the control program, and controls the alternating voltage E in a manner that achieves the calculated target effective value. There are no particular limitations on the control method; for example, feedback control can be used, that is, the alternating voltage E is controlled in a manner that compares the actual effective value and the target effective value, making the actual effective value close to (preferably consistent with) the target effective value.

[0131] Based on such control, such as Figure 10 As shown, the amplitude Y is maintained at the target amplitude Yt between 0 kPa and 50 kPa. That is, the amplitude Y is kept constant. This suppresses the amplitude at... Figure 8 The decrease in amplitude Y is shown in the diagram, which is caused by the increase in pressure within cuff 2. Furthermore, this is accompanied by, as... Figure 11 As shown, the degree of decrease in flow rate Q resulting from the increase in pressure within cuff 2 is related to... Figure 9 The difference is smaller compared to the case shown. Therefore, compared to the case where the alternating voltage E is constant, the pump system 10 can exhibit superior flow characteristics. Furthermore, the aforementioned "constant amplitude Y" refers not only to the case where the amplitude Y always remains at the target amplitude Yt, but also to the state where it fluctuates around the target amplitude Yt due to device structure, circuit structure, etc.

[0132] Furthermore, according to pump system 10, the control method is not complicated as in Patent Document 2, nor is it necessary to set up multiple pump sections with different volumes as in Patent Document 3. Therefore, pump system 10 can achieve excellent flow characteristics with a simple structure. And, as described above, the resonant frequency f of the vibration actuator 8... r The inertial torque J and the spring constant K sp The decision does not change based on the effective value of the alternating voltage E. Therefore, there is no need to deal with abnormal noises or malfunctions caused by the resonance phenomenon of pump 5, or even if such solutions are needed, they are easier to implement than in the case of using a motor in Patent Document 1. From this perspective, pump system 10 can also achieve excellent flow characteristics with a simple structure.

[0133] Furthermore, the waveform of the alternating voltage E is not particularly limited; for example, it can be... Figure 12 The sine wave shown can also be Figure 13 The triangular wave shown can also be Figure 14 The sawtooth wave shown can also be Figure 15 The rectangular wave shown. Among them, the waveform representing the alternating voltage E is preferably selected based on reasons such as minimizing noise generation. Figure 12 The sine wave shown is an example. However, conversely, the waveform generation circuit for a sine wave tends to be more expensive compared to other waveforms. Therefore, in the case of wanting to form a cheaper pump system 10, it is preferable to use a triangular wave, sawtooth wave, or rectangular wave.

[0134] In use Figure 12 , Figure 13 as well as Figure 14 When the sine wave, triangle wave, and sawtooth wave shown are used as alternating voltages E, methods for controlling the effective value of the alternating voltage E include, for example, changing the maximum voltage value Emax. The larger the maximum voltage value Emax, the larger the effective value; conversely, the smaller the maximum voltage value Emax, the smaller the effective value.

[0135] On the other hand, in use Figure 15 When the rectangular wave shown is used as the alternating voltage E, methods to change the effective value of the alternating voltage E include changing the maximum voltage value Emax and changing the duty cycle (=a / b). Similar to other waveforms, the larger the maximum voltage value Emax, the larger the effective value; conversely, the smaller the maximum voltage value Emax, the smaller the effective value. Furthermore, the larger the duty cycle, the larger the effective value; conversely, the smaller the duty cycle, the smaller the effective value. The drive control unit 61 can control both of these aspects, or only one of them. Depending on the method of controlling both, the effective value can be controlled more precisely compared to controlling only one aspect. Controlling only one aspect results in a simpler control than controlling both aspects, simplifying the circuit structure, etc.

[0136] The above describes the drive control method for pump 5 performed by drive control unit 61. In the above-described drive control method for pump 5, pressure detection unit 62 detects the pressure inside cuff 2 based on the output signal of pressure sensor 100, and drive control unit 61 controls the effective value of alternating voltage E based on the detection result. However, as a drive control method for pump 5, it is not particularly limited as long as the amplitude Y can be kept constant.

[0137] For example, based on the volume within cuff 2 and the flow rate Q obtained at the target amplitude Yt, the pressure rise within cuff 2 per unit time can be pre-calculated through experiments, simulations, etc. Thus, the relationship between the elapsed time from the start of pump 5's operation and the pressure within cuff 2 at that elapsed time can be deduced. Therefore, the drive control unit 61 can also have a control program that includes a table (timing table) relating the elapsed time from the start of pump 5's operation to the effective value of the alternating voltage E used to make amplitude Y reach the target amplitude Yt at that elapsed time, and a formula for calculating the effective value of the alternating voltage E used to make amplitude Y reach the target amplitude Yt at that elapsed time when the elapsed time from the start of pump 5's operation is substituted. The drive of pump 5 can be controlled based on this control program. According to this method, feedback of the pressure within cuff 2 is not required, thus simplifying the circuit structure.

[0138] The pump system, fluid supply device, and pump system drive control 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.

[0139] 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.

[0140] 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: A vibration actuator that is electromagnetically driven by applying alternating voltage; 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. Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object. The effective value of the alternating voltage is controlled in a way that makes the amplitude of the aforementioned vibration actuator constant. The object being measured is a cuff attached to the user's target measurement area. The pump system also includes: A pressure sensor is used to detect the pressure in the cuff; and A control device controls the actuation of a vibration actuator based on pressure detected in the cuff by a pressure sensor. The control device controls the effective value of the alternating voltage according to the pressure detected in the cuff by the pressure sensor, so as to keep the amplitude of the vibration actuator constant. The vibration actuator includes a shaft portion disposed in a housing, a movable body supported by the shaft portion to allow the movable wall to reciprocate relative to the housing, a pair of coil magnetic core portions fixed to one of the housing and the movable body, and a magnet disposed on the other of the housing or the movable body to face the coil magnetic core portions respectively. The aforementioned vibration actuator has a spring-mass system structure that supports the aforementioned movable body. The spring-mass system structure consists of a magnetic spring and a fluid spring. The magnetic spring is formed by the magnetic force acting between the magnetic core of the coil and the magnet, and the fluid spring is formed by the elastic force of the compressed fluid in the pair of sealed chambers.

2. The pump system according to claim 1, characterized in that, The effective value is controlled by varying the amplitude of the alternating voltage.

3. The pump system according to claim 1, characterized in that, The aforementioned alternating voltage is a rectangular wave. The effective value is controlled by changing at least one of the amplitude and duty cycle of the alternating voltage.

4. The pump system according to any one of claims 1 to 3, characterized in that, The pressure inside the aforementioned object is detected, and the effective value is controlled based on the detected pressure.

5. The pump system according to any one of claims 1 to 3, characterized in that, The resonant frequency of the aforementioned vibration actuator varies depending on the pressure within the aforementioned object.

6. The pump system according to claim 4, characterized in that, The resonant frequency of the aforementioned vibration actuator varies depending on the pressure within the aforementioned object.

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

8. A method for driving and controlling a pump system, the pump system comprising: A vibration actuator that is electromagnetically driven by applying alternating voltage; A sealed chamber connected to the inlet and outlet; and 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. Driven by the aforementioned vibration actuator, the movable wall is displaced, and the fluid in the sealed chamber is supplied to the object. The characteristic of the above-mentioned pump system drive control method is that, The effective value of the alternating voltage is controlled in a way that makes the amplitude of the aforementioned vibration actuator constant. The object being measured is a cuff attached to the user's target measurement area. The pump system also includes: A pressure sensor is used to detect pressure in the cuff; as well as A control device controls the actuation of a vibration actuator based on pressure detected in the cuff by a pressure sensor. The control device controls the effective value of the alternating voltage according to the pressure detected in the cuff by the pressure sensor, so as to keep the amplitude of the vibration actuator constant. The vibration actuator includes a shaft portion disposed in a housing, a movable body supported by the shaft portion to allow the movable wall to reciprocate relative to the housing, a pair of coil magnetic core portions fixed to one of the housing and the movable body, and a magnet disposed on the other of the housing or the movable body to face the coil magnetic core portions respectively. The aforementioned vibration actuator has a spring-mass system structure that supports the aforementioned movable body. The spring-mass system structure consists of a magnetic spring and a fluid spring. The magnetic spring is formed by the magnetic force acting between the magnetic core of the coil and the magnet, and the fluid spring is formed by the elastic force of the compressed fluid in the pair of sealed chambers.

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