PUMP SYSTEM, FLUID SUPPLY DEVICE, AND PRESSURE DETECTION METHOD

Abstract

To provide a pump system which omits a pressure sensor and detects a pressure in a cuff by using a pump to achieve downsizing, and to provide a fluid supply device and a pressure detection method.SOLUTION: A pump system 10 includes: a vibration actuator 8 which is driven electromagnetically; a sealing chamber 91 connected to a suction port 98 and a discharge port 99; and a movable wall 92 which changes a volume of the sealing chamber 91. Further, the movable wall 92 is displaced by the vibration actuator 8 being driven to supply air in the sealing chamber 91 to the interior of the cuff 2. The pump system 10 detects a pressure in the cuff 2 based on current consumption of the vibration actuator 8.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pump system, a fluid supply device, and a pressure detection method. [Background technology]

[0002] Each of Patent Documents 1, 2, and 3 describes an electronic blood pressure monitor for measuring a subject's blood pressure, which includes a cuff attached to the subject's arm, a pump that increases the pressure in the cuff by pumping air into the cuff, and a pressure sensor that detects the pressure in the cuff. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-146894 A [Patent Document 2] JP 2014-184071 A [Patent Document 3] JP 2017-209433 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in Patent Documents 1, 2 and 3, the pressure sensor is provided in addition to the pump, which poses the problem of a large number of parts and a large device size.

[0005] The present invention has been made in consideration of the above points, and aims to provide a pump system, a fluid supply device, and a pressure detection method that can be made smaller by eliminating the pressure sensor and configuring the pressure inside the cuff to be detected using a pump. [Means for solving the problem]

[0006] Such objectives are as follows: 8This is achieved by the present invention.

[0007] (1) an electromagnetically driven vibration actuator; Connected to the intake and exhaust ports A pair A sealed chamber; The above A pair The volume of the sealed chamber each Change Multiple Movable walls and a housing that houses the vibration actuator, the pair of sealed chambers, and the plurality of movable walls therein; Equipped with The vibration actuator is driven to Multiple The movable wall is displaced. A pair The fluid in the sealed chamber is supplied to the object; The pressure inside the object is detected based on the current consumption of the vibration actuator. death, the vibration actuator includes: a shaft portion provided within the housing; a movable body supported by the shaft portion so as to be rotatable back and forth relative to the housing; a pair of coil core portions fixed to one of the housing and the movable body; and a pair of magnets provided on the other of the housing and the movable body so as to face the pair of coil core portions, a spring mass structure for supporting the movable body is constituted by a magnetic spring formed by a magnetic force acting between the pair of coil core portions and the pair of magnets, and a fluid spring formed by the elasticity of a compressed fluid in the pair of sealed chambers, The drive frequency of the vibration actuator is set within a range in which the current consumption changes unilaterally as the pressure inside the object increases. A pump system comprising:

[0008] (2) The pump system according to (1) above, wherein the vibration actuator has a resonant frequency that changes depending on the pressure inside the object.

[0011] ( 3 The current consumption is the above-mentioned ( 1 ) The pump system described in. (4) The movable body has an elongated shape, The pump system according to (1) above, wherein the pair of magnets are provided at both ends of the movable body in the longitudinal direction. (5) The pump system according to (4) above, wherein the pair of coil core portions are provided on either side of the movable body in the longitudinal direction, symmetrically arranged with respect to each other across the shaft portion. (6) Each of the pair of magnets has an arc-shaped pole surface, each of the pair of coil core portions has an arc-shaped pole surface that faces the arc-shaped pole surface of the magnet; The pump system according to (1) above, wherein the arc-shaped pole faces of the pair of coil core portions face the arc-shaped pole faces of the pair of magnets, respectively.

[0012] ( 7 ) (1) or ( 6 2. A fluid supply device comprising the pump system according to claim 1.

[0013] ( 8 ) an electromagnetically driven vibration actuator; Connected to the intake and exhaust ports A pair A sealed chamber; The above A pair The volume of the sealed chamber each Change Multiple Movable walls and a housing that houses the vibration actuator, the pair of sealed chambers, and the plurality of movable walls therein; Equipped with The vibration actuator is driven to Multiple The movable wall is displaced. A pair In a pump system in which a fluid in a sealed chamber is supplied to an object, Detecting a current consumption of the vibration actuator; Based on a pre-stored relationship between the current consumption of the vibration actuator and the pressure within the object, The above Detected Vibration Actuator The above Current consumption from Within the object The above Detect pressure death, the vibration actuator includes: a shaft portion provided within the housing; a movable body supported by the shaft portion so as to be rotatable back and forth relative to the housing; a pair of coil core portions fixed to one of the housing and the movable body; and a pair of magnets provided on the other of the housing and the movable body so as to face the pair of coil core portions, a spring mass structure for supporting the movable body is constituted by a magnetic spring formed by a magnetic force acting between the pair of coil core portions and the pair of magnets, and a fluid spring formed by the elasticity of a compressed fluid in the pair of sealed chambers, The drive frequency of the vibration actuator is set within a range in which the current consumption changes unilaterally as the pressure inside the object increases. A pressure detection method comprising: Effect of the Invention

[0014] In the pump system of the present invention, the pressure inside the object is detected based on the current consumption of the electromagnetically driven vibration actuator. Therefore, the pressure inside the object can be detected without using a pressure sensor. This allows the number of parts to be reduced, and the pump system to be made smaller.

[0015] The fluid supply device of the present invention includes the pump system described above, and therefore can enjoy the effects of the pump system and can be made smaller in size.

[0016] Furthermore, in the pressure detection method of the present invention, the pressure inside the object is detected based on the current consumption of the electromagnetically driven vibration actuator. Therefore, the pressure inside the object can be detected without using a pressure sensor. Therefore, the number of parts in the pump system can be reduced, and the pump system can be made more compact. [Brief description of the drawings]

[0017] [Figure 1] 1 is a perspective view showing an overall configuration of an electronic blood pressure monitor according to a preferred embodiment; [Diagram 2] FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing the driving principle of the pump shown in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view showing the driving principle of the pump shown in FIG. 2. [Diagram 5] 3 is a schematic diagram showing a spring system of the vibration actuator. FIG. [Figure 6] 4 is a graph showing the relationship between the drive frequency and current consumption of the vibration actuator. [Figure 7] 13 is a graph showing the relationship between pressure in a sealed chamber and current consumption. [Figure 8] 11 is a graph showing the relationship between pressure in a sealed chamber and current consumption. [Figure 9] 13 is a graph showing the relationship between pressure in a sealed chamber and current consumption. [Figure 10] 13 is a graph showing the relationship between pressure in a sealed chamber and current consumption. [Figure 11] 13 is a graph showing the relationship between pressure in a sealed chamber and current consumption. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pump system, a fluid supply device, and a pressure detection method according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0019] FIG. 1 is a perspective view showing the overall configuration of an electronic blood pressure monitor according to a preferred embodiment. FIG. 2 is a cross-sectional view of a pump. FIGS. 3 and 4 are cross-sectional views showing the driving principle of the pump shown in FIG. 2. FIG. 5 is a schematic diagram showing a spring system of a vibration actuator. FIG. 6 is a graph showing the relationship between the driving frequency and current consumption of a vibration actuator. FIGS. 7 to 11 are graphs showing the relationship between the pressure in a sealed chamber and current consumption. In the following, for convenience of explanation, the upper side of the paper in FIGS. 2 to 4 will also be referred to as "upper", and the lower side will be referred to as "lower".

[0020] FIG. 1 shows an electronic blood pressure monitor 1 as a fluid supply device. Electronic blood pressure monitor 1 has a cuff 2, a main body 3, and a tube 4 for supplying and exhausting air that connects cuff 2 and main body 3. Cuff 2 is attached to a part of a subject to be measured, for example, an arm, and a bag inside cuff 2 expands with fluid supply from main body 3 to press against the part to be measured. Main body 3 measures the pressure inside cuff (object) 2, and calculates the blood pressure of the subject based on the measurement result. The fluid is not particularly limited and may be liquid or gas, but gas is preferable. In the following, for convenience of explanation, the fluid is described as air.

[0021] When blood pressure is measured according to a general oscillometric method, the procedure is as follows. First, the cuff 2 is wrapped around the part of the subject to be measured. Then, when measuring blood pressure, air is supplied from the main body 3 into the cuff 2 to make the pressure in the cuff 2 (cuff pressure) higher than the systolic blood pressure. The pressure is then gradually reduced, and during this process the pressure in the cuff 2 is detected by the main body 3, and the fluctuation in the arterial volume occurring in the artery at the part to be measured is extracted as a pulse wave signal. The systolic blood pressure (systolic blood pressure) and diastolic blood pressure (diastolic blood pressure) are calculated based on the change in the amplitude of the pulse wave signal accompanying the change in cuff pressure, mainly the rise and fall. However, the blood pressure measurement method is not particularly limited. For example, the Libarocchi-Korotkoff method, which is commonly used together with the oscillometric method, may be used.

[0022] 1, the main body 3 incorporates a pump system 10 including a pump 5 that supplies air into the cuff 2, and a control device 6 that controls the operation of the pump 5 and detects the pressure inside the cuff 2. In addition, as shown in FIG. 2, the pump 5 has a housing 7, a vibration actuator 8, and a pump unit 9.

[0023] The vibration actuator 8 has a shaft portion 81, a movable body 82 supported movably relative to the housing 7 via the shaft portion 81, and a pair of coil core portions 85, 86 fixed to the housing 7.

[0024] The movable body 82 is long, and is connected at its center to the housing 7 via the shaft portion 81. Therefore, the movable body 82 rotates back and forth relative to the housing 7 around the shaft portion 81 like a seesaw.

[0025] Magnets 83, 84 are provided at both ends of the movable body 82. These magnets 83, 84 are arranged symmetrically with respect to the shaft portion 81. The magnets 83, 84 have arc-shaped magnetic pole faces 831, 841 that face the coil core portions 85, 86. The magnetic pole faces 831, 841 have S poles and N poles arranged alternately along the arc direction. These magnets 83, 84 are permanent magnets, and are made of, for example, sintered Nd magnets or the like.

[0026] The movable body 82 is provided with pressers 87 and 88 that press the pump section 9 when the movable body 82 rotates back and forth. These pressers 87 and 88 are arranged symmetrically with respect to the shaft section 81. The presser 87 is arranged between the shaft section 81 and the magnet 83, and protrudes on both sides in the width direction of the movable body 82 (both sides in the vertical direction in FIG. 2). The presser 88 is arranged between the shaft section 81 and the magnet 84, and protrudes on both sides in the width direction of the movable body 82 (both sides in the vertical direction in FIG. 2).

[0027] The coil core portions 85 and 86 are disposed on either side of the movable body 82, with the coil core portion 85 facing a magnetic pole surface 831 of the magnet 83, and the coil core portion 86 facing a magnetic pole surface 841 of the magnet 84. These coil core portions 85 and 86 are disposed symmetrically with respect to the shaft portion 81.

[0028] The coil core portion 85 has a core portion 851 and a coil 859 wound around the core portion 851. The core portion 851 also has a core portion 852 around which the coil 859 is wound, and a pair of core poles 853, 854 extending from both ends of the core portion 852. The core poles 853, 854 also have pole faces 853a, 854a that face the pole face 831 of the magnet 83. The pole faces 853a, 854a are each curved in an arc shape following the pole face 831 of the magnet 83. The coil 859 is connected to the control device 6, and is supplied with power from the control device 6 to excite the core poles 853, 854 with different polarities.

[0029] The coil core portion 86 has a core portion 861 and a coil 869 wound around the core portion 861. The core portion 861 also has a core portion 862 around which the coil 869 is wound, and a pair of core poles 863, 864 extending from both ends of the core portion 862. The core poles 863, 864 also have pole faces 863a, 864a that face the pole face 841 of the magnet 84. The pole faces 863a, 864a are each curved in an arc shape following the pole face 841 of the magnet 84. The coil 869 is connected to the control device 6, and is supplied with power from the control device 6 to excite the core poles 863, 864 with different polarities.

[0030] Core portions 851, 861 are magnetic bodies that are magnetized when current is passed through coils 859, 869, respectively, and are made of, for example, electromagnetic stainless steel, sintered material, MIM (metal injection molding) material, laminated steel plate, electro-galvanized steel plate (SECC), etc.

[0031] The four pump sections 9 are arranged vertically and horizontally with respect to the shaft section 81. Specifically, two pump sections 9 are arranged vertically facing each other via one pressing element 87, and the remaining two pump sections 9 are arranged vertically facing each other via the other pressing element 88. These four pump sections 9 have the same configuration, and each has a sealed chamber 91 and a movable wall 92.

[0032] The sealed chamber 91 is connected to an intake port 98 that draws in air from the outside and an exhaust port 99 that exhausts air from within the sealed chamber 91. In this embodiment, two sealed chambers 91 located above the movable body 82 share one exhaust port 99, and two sealed chambers 91 located below the movable body 82 share one exhaust port 99.

[0033] The movable wall 92 constitutes a part of the sealed chamber 91. The movable wall 92 is displaced by being pressed by the pressing members 87 and 88, and changes the volume of the sealed chamber 91. When the volume of the sealed chamber 91 decreases due to the displacement of the movable wall 92, the air in the sealed chamber 91 is discharged from the discharge port 99, and conversely, when the volume of the sealed chamber 91 increases, air flows into the sealed chamber 91 from the intake port 98. Such a decrease and increase in the volume of the sealed chamber 91 is repeated, and air is continuously discharged from the discharge port 99. The movable wall 92 is, for example, a diaphragm, and is formed of an elastically deformable material. The movable wall 92 has an insertion portion 921 into which the pressing members 87 and 88 are inserted, and is connected to the pressing members 87 and 88 via the insertion portion 921.

[0034] Furthermore, a valve 93 is provided between the sealed chamber 91 and the suction port 98. The valve 93 allows air to be sucked into the sealed chamber 91 from the suction port 98, and regulates the discharge of air from the sealed chamber 91 to the suction port 98. Furthermore, a valve 94 is provided between the sealed chamber 91 and the discharge port 99. The valve 94 allows air to be discharged from the sealed chamber 91 to the discharge port 99, and regulates the intake of air from the discharge port 99 to the sealed chamber 91. This makes it possible to more reliably and efficiently suck in and discharge air.

[0035] 1, the control device 6 has a drive control unit 61 that controls the drive of the vibration actuator 8, and a pressure detection unit 62 that detects the pressure inside the cuff 2. The control device 6 is, for example, configured as a computer, and has a processor (CPU) that processes information, a memory communicatively connected to the processor, and an external interface. In addition, various programs that can be executed by the processor are stored in the memory, and the processor reads and executes the various programs stored in the memory.

[0036] The above describes the configuration of electronic blood pressure monitor 1. Next, a description will be given of the driving of pump 5. For ease of explanation, the four pump units 9 will be distinguished below as "pump unit 9A," "pump unit 9B," "pump unit 9C," and "pump unit 9D."

[0037] When an AC voltage is applied from the drive control unit 61 to the coils 859 and 869, the pump 5 is driven by repeatedly switching between a first state in which the movable body 82 rotates to one side as shown in Fig. 3 and a second state in which the movable body 82 rotates to the other side as shown in Fig. 4. In the first state shown in Fig. 3, the core magnetic poles 853 and 864 are each excited to the N pole, and the core magnetic poles 854 and 863 are each excited to the S pole. Conversely, in the second state shown in Fig. 4, the core magnetic poles 853 and 864 are each excited to the S pole, and the core magnetic poles 854 and 863 are each excited to the N pole.

[0038] In the first state, torque F1 in the direction of the arrow is generated by magnetic forces (attractive and repulsive forces) acting between magnets 83, 84 and coil cores 85, 86, and movable body 82 rotates in the direction of torque F1. As a result, in pumps 9A, 9D, movable wall 92 is pressed by pushers 87, 88, the volume of sealed chamber 91 decreases, and air in sealed chamber 91 is discharged from discharge port 99. The discharged air is then supplied into cuff 2 via tube 4, and the pressure in cuff 2 increases. Conversely, in pumps 9B, 9C, the volume of sealed chamber 91 increases, and air flows into sealed chamber 91 from suction port 98.

[0039] In the second state, a torque F2 in the opposite direction to the torque F1 is generated by the magnetic forces (attraction and repulsion) acting between the magnets 83, 84 and the coil cores 85, 86, and the movable body 82 rotates in the direction of the torque F2. As a result, in the pumps 9B, 9C, the movable wall 92 is pressed by the pressers 87, 88, the volume of the sealed chamber 91 decreases, and the air in the sealed chamber 91 is discharged from the discharge port 99. The discharged air is then supplied into the cuff 2 via the tube 4, and the pressure in the cuff 2 increases. Conversely, in the pumps 9A, 9D, the volume of the sealed chamber 91 increases, and air flows into the sealed chamber 91 from the suction port 98.

[0040] In this way, by alternately repeating the first state and the second state, a state in which air is discharged from pump units 9A, 9D and a state in which air is discharged from pump units 9B, 9C are alternately repeated, and air is continuously discharged from pump 5. Therefore, air can be efficiently supplied to cuff 2, and the pressure in cuff 2 can be smoothly increased.

[0041] The above describes the driving of the pump 5. Next, a description will be given of the driving principle of the pump 5. The vibration actuator 8 is driven based on the equation of motion shown in the following formula (1) and the circuit equation shown in the following formula (2).

[0042]

number

[0043]

number

[0044] Thus, the moment of inertia J [Kg*m 2], displacement angle (rotation angle) θ(t) [rad], torque constant Kt [Nm / A], current i(t) [A], spring constant Ksp [N / m], damping coefficient D [Nm / (rad / s)], etc. can be set appropriately within a range that satisfies formula (1). Similarly, voltage e(t) [V], resistance R [Ω], inductance L [H], and back electromotive force constant Ke [V / (m / s)] can be set appropriately within a range that satisfies formula (2).

[0045] In addition, in the pump 5, the flow rate is set by the following formula (3), and the pressure is set by the following formula (4).

[0046]

number

[0047]

number

[0048] In this way, the flow rate Q [L / min] and the piston area A [m 2 ], piston displacement x [m], drive frequency f [Hz], etc. can be appropriately set within the range that satisfies formula (3). Similarly, the increased pressure P [kPa], atmospheric pressure P0 [kPa], sealed chamber volume V [m 3 ], fluctuating volume ΔV [m 3 ] etc. can be appropriately set within a range that satisfies formula (4).

[0049] Next, we will explain the resonance frequency of vibration actuator 8. As shown in Fig. 5, vibration actuator 8 has a spring-mass system structure that supports movable body 82 by magnetic spring B1 formed by magnetic force acting between coil core parts 85, 86 and magnets 83, 84, and air spring (fluid spring) B2 formed by the elasticity of compressed air in sealed chamber 91. Therefore, movable body 82 has a resonance frequency fr shown in the following formula (5).

[0050]

number

[0051] Furthermore, the spring constant Ksp is the spring constant K of the vibration actuator 8 itself including the magnetic spring B1 and the elasticity B3 of the movable wall 92, as shown in the following formula (6): ACT and the spring constant K of air spring B2 Air It is expressed as the sum of and.

[0052]

number

[0053] As can be seen from the above formulas (5) and (6), in the vibration actuator 8, the spring constant K of the air spring B2 is changed by the pressure in the sealed chamber 91 (pressure in the cuff 2). Air changes, which in turn changes the resonance frequency fr of the movable body 82. Therefore, in the pump system 10, attention is focused on the change in power consumption of the vibration actuator 8 that occurs in conjunction with this change in resonance frequency fr, and the pressure inside the sealed chamber 91 is detected based on this change in current consumption.

[0054] Next, a pressure detection method based on the power consumption of the vibration actuator 8 will be specifically described. For convenience of explanation, the pump 5 capable of increasing the pressure in the cuff 2 to a maximum of 50 kPa will be described as a representative example. However, the maximum pressure is not particularly limited and can be set appropriately to meet the required conditions. As described above, the cuff 2 and the sealed chamber 91 are connected via the tube 4, and therefore have the same pressure. Therefore, the "pressure in the sealed chamber 91" and the "pressure in the cuff 2" are synonymous.

[0055] Fig. 6 shows the relationship between the drive frequency f and the current consumption of vibration actuator 8 when the pressure inside cuff 2 is 0 kPa to 50 kPa. The current consumption of vibration actuator 8 refers to the current flowing inside the main circuit of vibration actuator 8, and mainly means the current flowing in the circuit for supplying current to coils 859, 869. The alternating voltage applied to coils 859, 869 is constant. Note that the relationship shown in Fig. 6 is an example, and the present invention is not limited to this relationship.

[0056] In FIG. 6, the drive frequency f at which the current consumption is the smallest at each pressure is almost equal to the resonance frequency fr. Therefore, as the pressure in the cuff 2 increases, the spring constant K Air increases and the resonance frequency fr becomes higher.

[0057] 6, the current consumption of the vibration actuator 8 decreases as the pressure in the cuff 2 increases in the region where the drive frequency f is between fmin and fmax. That is, the current consumption changes unilaterally (either decreasing or increasing) as the pressure in the cuff 2 increases. In the pump 5, the drive frequency f is set within a region where the current consumption changes unilaterally as the pressure in the cuff 2 increases, such as within the range of fmin to fmax. Note that the drive frequency f may be fixed at an initial value and may not be changeable, or may be set by the user as appropriate within the range of fmin to fmax. In the following, for convenience of explanation, a case where the drive frequency f is fixed at fn will be representatively explained.

[0058] 7 shows the relationship between the pressure inside the sealed chamber 91 at drive frequency f=fn and the current consumption of the vibration actuator 8. As shown in the figure, at drive frequency f=fn, as the pressure inside the cuff 2 increases, the current consumption of the vibration actuator 8 decreases linearly.

[0059] The pressure detection unit 62 of the control device 6 stores in advance the relationship between the pressure inside the cuff 2 at drive frequency f=fn and the current consumption of the vibration actuator 8 as a table or a formula. The pressure detection unit 62 then detects the current consumption of the vibration actuator 8 and obtains the pressure inside the cuff 2 by applying the detected current consumption to the table or a function. In particular, in this embodiment, the current consumption of the vibration actuator 8 decreases linearly, so that the degree of change in the current consumption relative to the pressure inside the cuff 2 is substantially uniform and sufficiently large over the entire pressure range from 0 kPa to 50 kPa. Therefore, the pressure inside the cuff 2 can be detected with high accuracy over the entire pressure range.

[0060] In this way, according to the pump system 10, the pressure in the cuff 2 can be detected by utilizing the characteristics of the pump 5 itself without using a pressure sensor. Therefore, unlike the conventional art, it is not necessary to provide a separate member such as a pressure sensor for detecting the pressure in the cuff 2 separately from the pump 5. Therefore, the number of parts in the pump system 10 is reduced, and the pump system 10 can be made more compact. In particular, since the vibration actuator 8 has a characteristic that the resonant frequency fr changes depending on the pressure in the cuff 2, the vibration actuator 8 can easily be given a characteristic that the current consumption changes with the change in the pressure in the cuff 2. Furthermore, since the vibration actuator 8 has the air spring B2, the vibration actuator 8 can be given a characteristic that the resonant frequency fr changes depending on the pressure in the cuff 2 with a simple configuration.

[0061] The method for setting the drive frequency f is not particularly limited, but can be set, for example, as follows. The closer the drive frequency f is to the resonance frequency fr, the larger the amplitude of the vibration actuator 8 becomes, and the flow rate Q of the air discharged from the pump 5 can be increased. Furthermore, the closer the drive frequency f is to the resonance frequency fr, the more energy-saving the drive of the vibration actuator 8 becomes. On the other hand, the greater the difference between the current consumption of the vibration actuator 8 at 0 kPa and the current consumption of the vibration actuator 8 at 50 kPa, the greater the degree of change in the current consumption relative to the pressure inside the cuff 2, and the more accurately the pressure inside the cuff 2 can be detected.

[0062] Therefore, it is preferable to set the driving frequency f to a frequency between the resonance frequency fr at 0 kPa and the resonance frequency fr at 50 kPa, where the difference between the current consumption at 0 kPa and the current consumption at 50 kPa is maximum or in the vicinity thereof (for example, within a range of 90% from the maximum value). With such a driving frequency f, the pressure in the cuff 2 can be detected more accurately while driving the pump 5 efficiently. For this reason, in this embodiment, the driving frequency f is set to a frequency fn between the resonance frequency fr at 0 kPa and the resonance frequency fr at 50 kPa, where the difference between the current consumption at 0 kPa and the current consumption at 50 kPa is maximum.

[0063] In addition, in Fig. 7, the current consumption of the vibration actuator 8 decreases linearly as the pressure inside the cuff 2 increases, but this is not limited thereto, and may decrease nonlinearly, for example, as shown in Fig. 8. In this case, in a region where the pressure inside the cuff 2 is low, the degree of change in the current consumption relative to the pressure is large, so the pressure inside the cuff 2 can be detected with higher accuracy. On the other hand, in a region where the pressure inside the cuff 2 is high, the degree of change in the current consumption relative to the pressure tends to be small, and it may not be possible to detect the pressure inside the cuff 2 with sufficient accuracy. In this respect, the linearity shown in Fig. 7 is superior.

[0064] 7, the current consumption of the vibration actuator 8 changes unilaterally in the decreasing direction as the pressure inside the cuff 2 increases, but this is not limited thereto, and for example, as shown in Fig. 9, the current consumption of the vibration actuator 8 may change unilaterally in the increasing direction as the pressure inside the cuff 2 increases. In such a case, the degree of change in the current consumption relative to the pressure inside the cuff 2 becomes sufficiently large over the entire pressure range, as in Fig. 7. Therefore, the pressure inside the cuff 2 can be detected with high accuracy over the entire pressure range.

[0065] 7, the current consumption of the vibration actuator 8 changes unilaterally in the decreasing direction as the pressure inside the cuff 2 increases, but this is not limited thereto, and for example, as shown in FIG. 10, it may decrease and then increase, or as shown in FIG. 11, it may increase and then decrease. In this case, however, the same current consumption may be indicated at different pressures on either side of an extreme value, and some ingenuity is required to distinguish between these. For example, by continuously detecting the current consumption from a state in which the pressure is sufficiently low and judging whether or not it exceeds an extreme value (the minimum value in FIG. 10, the maximum value in FIG. 11), it is possible to judge whether the pressure is lower than the extreme value or higher than the extreme value.

[0066] In the above explanation, the driving frequency f is fixed at fn. However, if the user can appropriately select the driving frequency f from a number of values, for example, the relationship between the pressure in the cuff 2 and the current consumption for each selectable driving frequency f can be stored in the pressure detection unit 62 as a table or function, and the pressure in the cuff 2 can be determined using the table or function corresponding to the selected driving frequency f.

[0067] Although the pump system, the fluid supply device, and the pressure detection method of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention.

[0068] Also, for example, in the above-described embodiment, the pump system and the fluid supply device are applied to electronic blood pressure monitor 1, but the present invention is not limited thereto and can be applied to any instrument that requires a fluid supply. Also, for example, in the above-described embodiment, pump 5 has four pump units 9, but the present invention is not limited thereto and can be applied to any instrument that requires a fluid supply.

[0069] Furthermore, the configuration of the vibration actuator 8 is not particularly limited as long as the current consumption changes according to the pressure inside the sealed chamber 91. For example, in the above-described embodiment, the magnets 83, 84 are provided on the movable body 82, and the coil core parts 85, 86 are provided on the housing 7, but this is not limited thereto, and the reverse may also be true. In other words, the coil core parts 85, 86 may be provided on the movable body 82, and the magnets 83, 84 may be provided on the housing 7. Furthermore, the magnets 83, 84 may be replaced with electromagnets. [Explanation of symbols]

[0070] 1...Electronic blood pressure monitor 2...Cuff (object) 3...Main body 4...Tube 5...Pump 6...Control device 7...Housing 8...Vibration actuator 9, 9A, 9B, 9C, 9D...Pump section 10...Pump system 61...Drive control section 62...Pressure detection section 81...Axis section 82...Movable body 83, 84...Magnet 85, 86...Coil core section 87, 88...Pressing element 91...Sealed chamber 92...Movable wall 93, 94...Valve 98...Suction port 99...Discharge port 831, 841...Magnetic pole surface 851, 861...Core section 852, 862...Core section 853, 854, 863, 864...Core magnetic pole 853a, 854a, 863a, 864a...Magnetic pole surface 859, 869...Coil 921...Insertion section B1...Magnetic spring B2...Air spring (fluid spring) B3...Elasticity F1, F2...Torque

Claims

1. an electromagnetically driven vibration actuator; A pair of sealed chambers connected to an inlet and an outlet; A plurality of movable walls each changing a volume of the pair of sealed chambers; a housing that houses the vibration actuator, the pair of sealed chambers, and the plurality of movable walls therein, the vibration actuator is driven to displace the plurality of movable walls, and the fluid in the pair of sealed chambers is supplied to a target object; detecting a pressure inside the object based on a current consumption of the vibration actuator; the vibration actuator includes: a shaft portion provided within the housing; a movable body supported by the shaft portion so as to be rotatable back and forth relative to the housing; a pair of coil core portions fixed to one of the housing and the movable body; and a pair of magnets provided on the other of the housing and the movable body so as to face the pair of coil core portions, a spring mass structure for supporting the movable body is constituted by a magnetic spring formed by a magnetic force acting between the pair of coil core portions and the pair of magnets, and a fluid spring formed by the elasticity of a compressed fluid in the pair of sealed chambers, A pump system, comprising: a drive frequency of the vibration actuator that is set within a range in which the current consumption changes unilaterally as the pressure in the object increases.

2. The pump system according to claim 1 , wherein the vibration actuator has a resonant frequency that changes depending on a pressure inside the object.

3. The pump system according to claim 1 , wherein the current consumption varies linearly.

4. The movable body has an elongated shape, The pump system according to claim 1 , wherein the pair of magnets are provided at both ends of the movable body in a longitudinal direction.

5. A pump system as described in claim 4, wherein the pair of coil core portions are respectively arranged symmetrically with respect to each other via the shaft portion, on either side of the longitudinal direction of the movable body.

6. Each of the pair of magnets has an arc-shaped pole face, each of the pair of coil core portions has an arc-shaped pole surface that faces the arc-shaped pole surface of the magnet; The pump system according to claim 1 , wherein the arcuate magnetic pole faces of the pair of coil core portions face the arcuate magnetic pole faces of the pair of magnets, respectively.

7. A fluid supply device comprising a pump system according to any one of claims 1 to 6.

8. an electromagnetically driven vibration actuator; A pair of sealed chambers connected to an inlet and an outlet; A plurality of movable walls each changing a volume of the pair of sealed chambers; a housing that houses the vibration actuator, the pair of sealed chambers, and the plurality of movable walls therein, In a pump system in which the vibration actuator is driven to displace the plurality of movable walls to supply fluid in the pair of sealed chambers to an object, Detecting a current consumption of the vibration actuator; detecting the pressure within the object from the detected current consumption of the vibration actuator based on a pre-stored relationship between the current consumption of the vibration actuator and the pressure within the object; the vibration actuator includes: a shaft portion provided within the housing; a movable body supported by the shaft portion so as to be rotatable back and forth relative to the housing; a pair of coil core portions fixed to one of the housing and the movable body; and a pair of magnets provided on the other of the housing and the movable body so as to face the pair of coil core portions, a spring mass structure for supporting the movable body is constituted by a magnetic spring formed by a magnetic force acting between the pair of coil core portions and the pair of magnets, and a fluid spring formed by the elasticity of a compressed fluid in the pair of sealed chambers, A pressure detection method, comprising: a drive frequency of the vibration actuator set within a range in which the current consumption changes unilaterally as the pressure inside the object increases.

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