Electromagnetic air pump and sphygmomanometer

Abstract

The present application relates to the field of air pumps, and in particular to an electromagnetic air pump and a sphygmomanometer. The electromagnetic air pump includes a cylinder, a fixed frame, a coil, and a magnetic part arranged inside the fixed frame. The coil drives the magnetic part to drive the cylinder to deform and change the volume of air in the cylinder. The cylinder is provided with an air inlet hole, and external air enters the cylinder through the air inlet hole. A flap made of elastic material is used to close the air inlet hole. When external air enters the cylinder through the air inlet hole, the flap opens, and when the air in the cylinder flows out of the cylinder, the flap closes. The present invention realizes the miniaturization of the electromagnetic air pump and the sphygmomanometer by changing the driving mode and air intake mode of the cylinder in the air pump.

Description

Technical Field

[0001] The present application relates to the field of air pumps, and in particular to an electromagnetic air pump and a sphygmomanometer. Background Art

[0002] In an electronic blood pressure monitor, an air pump is needed to inflate the armband so that the armband can apply pressure to the arm. Since the users of electronic blood pressure monitors often need to use the monitors in different scenarios, how to make the electronic blood pressure monitors more compact and portable has become an urgent problem to be solved in the industry. Currently, most air pumps in electronic blood pressure monitors use motors to drive the piston of the cylinder to achieve inflation and deflation. At the same time, one-way valves need to be set at the air inlet and outlet of the cylinder to control the flow direction of the air in the cylinder. Due to the large size of the motor and the one-way valve, the size of the air pump is also large, making it difficult to miniaturize the electronic blood pressure monitor. Summary of the invention

[0003] In order to achieve miniaturization of an electronic sphygmomanometer by miniaturizing an electromagnetic air pump, the present application provides an electromagnetic air pump and a sphygmomanometer.

[0004] In a first aspect, the present application provides an electromagnetic air pump, which adopts the following technical solution:

[0005] An electromagnetic air pump, comprising a cylinder, a fixed frame, a coil, and a reset member and a magnetic member both arranged inside the fixed frame, wherein the cylinder body is fixed relative to the fixed frame, the coil is located at the periphery of the fixed frame, the coil is used to drive the magnetic member to move in a direction close to the cylinder body, and the reset member is used to drive the magnetic member to move in a direction away from the cylinder body;

[0006] The cylinder comprises a cylinder body and a flap, the flap is made of an elastic material, a cylinder wall of the cylinder body is provided with an extrusion portion, the extrusion portion is made of an elastic material, the magnetic member drives the extrusion portion to deform to increase or decrease the volume of air in the cylinder body, and the extrusion portion is provided with an air inlet for air outside the cylinder body to enter the cylinder body;

[0007] When the air volume in the cylinder body decreases, the valve plate closes the air inlet hole. When the air volume in the cylinder body increases, the interior of the cylinder body is connected to the outside of the cylinder body through the air inlet hole.

[0008] By adopting the above technical solution, the air volume in the cylinder is changed by electromagnetically driving the movement of the magnetic parts instead of using a motor to drive, thereby achieving the effect of reducing the volume of the electromagnetic air pump; a valve plate is provided for closing the air inlet hole, so that the valve plate is in an open state when the gas enters the cylinder and in a closed state when the gas exits the cylinder, so that the cylinder can control the flow direction of the air without using a one-way valve, thereby realizing the miniaturization of the electromagnetic air pump.

[0009] Optionally, one end of the flap is connected to the cylinder body, and the other end of the flap is a free end; when the air volume in the cylinder body decreases, the end surface of the magnetic component limits the movement of the free end of the flap.

[0010] By adopting the above technical solution, the end surface of the magnetic part is used to limit the movement of the valve plate when the gas exits the cylinder, so that the valve plate remains in a closed state of the air inlet hole, thereby achieving the air tightness of the air inlet hole and making the structure of the electromagnetic air pump more compact.

[0011] Optionally, the magnetic component is provided with an air delivery groove, the air inlet end of the air delivery groove is connected to the outside of the magnetic component, and the air outlet end of the air delivery groove is connected to the air inlet hole.

[0012] By adopting the above technical solution, the gas delivery groove on the magnetic part is used to deliver gas to the cylinder, so that the structure of the electromagnetic air pump is compact, which is conducive to the miniaturization of the electromagnetic air pump.

[0013] Optionally, the extrusion portion is provided with a clearance groove communicated with the air inlet hole, the flap is located inside the air inlet hole, and the end surface of the magnetic member closes the clearance groove by abutting against the extrusion portion.

[0014] By adopting the above technical solution, the clearance groove is used to make way for the flap, so that when the flap changes from an open state to a closed state, it will not be difficult to reset due to being stuck by the hole wall of the air inlet hole, thereby reducing the occurrence of gas leakage from the air inlet hole due to the flap not being completely reset. At the same time, the clearance groove is closed by the end face of the magnetic part to prevent air leakage from the clearance groove.

[0015] Optionally, the cylinder further includes a transmission connecting member, the transmission connecting member is connected to the extrusion portion, the magnetic member is clamped with the transmission connecting member, and an end surface of the magnetic member abuts against the extrusion portion.

[0016] By adopting the above technical solution, the connection between the extrusion part and the magnetic part is realized by using a transmission connecting part, which makes it easy for workers to quickly assemble the extrusion part and the magnetic part during production. At the same time, the magnetic part transmits power to the extrusion part by contacting the extrusion part, making the structure of the electromagnetic air pump compact and conducive to miniaturization.

[0017] Optionally, the electromagnetic air pump further includes a fixed cover, which is fixed relative to the fixed frame. The cylinder further includes a connecting ear connected to the cylinder body, and the fixed cover and the fixed frame clamp the connecting ear.

[0018] By adopting the above technical solution, the fixing cover and the fixing frame are used to clamp the connecting ears, so that the cylinder body, the fixing cover and the fixing frame can be quickly fixed relative to each other during assembly.

[0019] Optionally, the fixed cover is provided with an air cabin, the air cabin is provided with an opening for an air outlet passage of the cylinder body to extend into the interior of the air cabin, the connecting ear is located at the outer periphery of the cylinder body, the connecting ear is made of elastic material, the connecting ear is used to close the opening, and the fixed cover is provided with an outlet pipe for the air inside the air cabin to flow to the outside of the fixed cover.

[0020] By adopting the above technical solution, the opening is closed by using the connecting ear to prevent air leakage from the opening, so that the electromagnetic air pump can use the outlet pipe to stably inflate the air to the outside, and the connecting ear can be used to fix the cylinder body and to achieve the air tightness of the air cabin, which has the effect of one thing for multiple uses.

[0021] Optionally, a protrusion is provided on the inner wall of the air chamber, and the protrusion extends into the interior of the cylinder body through the air outlet channel, and the inner wall of the air outlet channel abuts against the outer surface of the protrusion.

[0022] By adopting the above technical solution, on the one hand, the cylinder body is limited by the protrusion to reduce the occurrence of gas leakage caused by the self-displacement of the cylinder body during use; on the other hand, the volume inside the cylinder body is reduced by the protrusion, so that the air can quickly fill the inside of the cylinder body, and the extrusion part can drive the air in the cylinder body to be discharged from the air outlet channel to the outside of the cylinder body with a smaller displacement or deformation.

[0023] Optionally, the electromagnetic air pump includes a fixing frame, and the fixing cover and the fixing frame are respectively connected to the fixing frame.

[0024] By adopting the above technical solution, the fixed cover and the fixed frame are respectively connected to the fixed frame to achieve relative fixation between the fixed cover and the fixed frame.

[0025] In a second aspect, the present application provides a sphygmomanometer, which adopts the following technical solution:

[0026] A sphygmomanometer comprises the electromagnetic air pump.

[0027] By adopting the above technical solution, a smaller electromagnetic air pump is used in the sphygmomanometer, so that the sphygmomanometer is smaller in size and more portable.

[0028] In summary, the present application includes at least one of the following beneficial technical effects:

[0029] 1. Use electromagnetic drive to move the magnetic parts to change the air volume in the cylinder instead of using motor drive to achieve the effect of reducing the volume of the electromagnetic air pump;

[0030] 2. A flap is provided for closing the air inlet hole, so that the flap is in an open state when the gas enters the cylinder and in a closed state when the gas exits the cylinder, so that the cylinder can control the flow direction of the air without using a one-way valve, thereby realizing the miniaturization of the electromagnetic air pump;

[0031] 3. The clearance groove is provided to enable the flap in the air inlet hole to be completely reset, thereby reducing the air leakage from the air inlet hole caused by the flap not being completely reset. At the same time, the clearance groove is sealed with the end surface of the magnetic part to prevent air leakage from the clearance groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a three-dimensional structural diagram of the present invention.

[0033] Figure 2 It is an exploded view of the present invention.

[0034] Figure 3 It is a diagram of the internal structure of the first embodiment of the present invention when the flap is open.

[0035] Figure 4 It is a diagram of the internal structure of the first embodiment of the present invention when the flap is in a closed state.

[0036] Figure 5 It is a top view of the cylinder of the first embodiment of the present invention after the flap is hidden.

[0037] Figure 6 It is a three-dimensional structural diagram of the fixing cover of the first embodiment of the present invention.

[0038] Figure 7 It is a diagram of the internal structure of the second embodiment of the present invention when the flap is open.

[0039] Figure 8 It is a bottom view of the electromagnetic air pump according to the second embodiment of the present invention.

[0040] Fig. 9 It is a diagram of the internal structure of the third embodiment of the present invention when the flap is open.

[0041] Fig.10 It is a diagram of the internal structure of the third embodiment of the present invention when the flap is in a closed state.

[0042] Explanation of the reference numerals: 1. fixing frame; 11. fixing slot; 12. riveting slot; 13. vent hole; 2. fixing cover; 21. riveting block; 22. air outlet pipe; 23. air chamber; 24. protrusion; 3. cylinder; 31. cylinder body; 311. extrusion part; 3111. air inlet hole; 3112. clearance slot; 312. air outlet channel; 32. flap; 33. connecting ear; 34. transmission connecting part; 341. slide slot; 342. limiting block; 343. air inlet slot; 4. fixing frame; 41. fixing block; 42. connecting slot; 5. coil; 6. shock-absorbing pad; 7. reset member; 8. magnetic member; 81. gasket; 82. transmission block; 83. boss; 84. limiting block; 85. air delivery slot; 9. positioning member; 91. through hole. DETAILED DESCRIPTION

[0043] The present application is further described in detail below in conjunction with the accompanying drawings.

[0044] Embodiment 1

[0045] The present application embodiment discloses a small electromagnetic air pump used in an electronic blood pressure monitor. Figure 1 to Figure 2 The electromagnetic air pump includes a fixing frame 1, a fixing cover 2, a cylinder 3, a fixing frame 4, a coil 5, a shock-absorbing pad 6, and a reset member 7, a magnetic member 8, a positioning member 9 and a gasket 81 all arranged inside the fixing frame 4. Figures 2 to 4 , the cylinder 3 includes a cylinder body 31, a flap 32, a connecting ear 33 and a transmission connecting member 34, and the entire cylinder 3 is formed in one piece. The cylinder wall of the cylinder body 31 is provided with an extrusion portion 311. The cylinder wall specifically refers to the entire wall forming the cylinder body 31, rather than the inner surface or outer surface of the wall alone. The outer wall of the positioning member 9 is connected to the inner wall of the fixed skeleton 4. Specifically, when manufacturing the fixed skeleton 4, the positioning member 9 is placed in the mold and then injection molded, so that the positioning member 9 and the fixed skeleton 4 become one. One end of the magnetic member 8 has a smaller cross-sectional area and is provided with a transmission block 82. The outer periphery of the other end of the magnetic member 8 is provided with a boss 83 and a limit block 84, and the end of the other end is connected to the shock-absorbing pad 6. The limit block 84 and the boss 83 are arranged in sequence in the direction away from the cylinder 3, and the cross-sectional area of ​​the limit block 84 is smaller than the cross-sectional area of ​​the boss 83. The shock-absorbing pad 6 protrudes relative to the end face of the magnetic member 8.

[0046] Reference Figure 2 and Figure 3, when assembling, first put the reset member 7 into the fixed frame 4, so that one end of the reset member 7 abuts against the positioning member 9. Install the magnetic member 8 into the fixed frame 4, and after the end with a smaller cross-sectional area of ​​the magnetic member 8 passes through the connecting hole of the gasket 81 and the through hole 91 of the positioning member 9 in turn, the other end of the reset member 7 abuts against the boss 83 of the magnetic member 8. Among them, the reset member 7 is a spring. After the transmission connecting member 34 of the cylinder 3 is engaged with the transmission block 82 of the magnetic member 8, the end of the magnetic member 8 abuts against the extrusion portion 311 of the cylinder body 31. At the same time, the connecting ear 33 of the cylinder 3 is placed in the connecting groove 42 of the fixed frame 4. After the coil 5 is wound around the outer periphery of the fixed frame 4, the fixed frame 4 is placed in the U-shaped fixed frame 1, and the fixed block 41 at the bottom of the fixed frame 4 is engaged with the fixed slot 11 at the bottom of the fixed frame 1, so that the fixed frame 4 cannot rotate. The fixing cover 2 is covered on the fixing frame 4 and the fixing frame 1, so that the air outlet channel 312 of the cylinder body 31 extends into the air chamber 23 through the opening of the air chamber 23 of the fixing cover 2, and the protrusion 24 of the fixing cover 2 extends into the interior of the cylinder body 31 through the air outlet channel 312, and the riveting block 21 of the fixing cover 2 is riveted with the riveting groove 12 of the fixing frame 1, thereby achieving the fixation between the fixing cover 2 and the fixing frame 1. After the fixing cover 2 is covered, the fixing cover 2 and the fixing frame 4 clamp the connecting ear 33 of the cylinder 3, thereby achieving the fixation of the cylinder body 31.

[0047] Reference Figures 2 to 5, the flap 32 of the cylinder 3 is made of elastic material, the flap 32 is located inside the air inlet hole 3111 of the cylinder 3, and one end of the flap 32 is connected to the inner wall of the air inlet hole 3111, and the other end of the flap 32 is a free end. The flap 32 is located inside the air inlet hole 3111 of the cylinder 3, and the other end of the flap 32 is connected to the hole wall of the air inlet hole 3111. The flap 32 achieves the air tightness of the air inlet hole 3111 by blocking the air inlet hole 3111. When using an electromagnetic air pump, the external chip controls the power supply to energize the coil 5, and the coil 5 generates an electromagnetic force to drive the magnetic part 8 to move in the direction close to the body of the cylinder 3, and the magnetic part 8 drives the reset part 7 to compress. The limit block 84 cannot pass through the through hole 91 of the positioning member 9, so it can limit the magnetic part 8 and prevent the coil 5 from over-driving the magnetic part 8, resulting in an excessive stroke of the magnetic part 8. In order to prevent the limit block 84 from colliding with the positioning member 9 and causing damage, a gasket 81 made of soft material is arranged between the limit block 84 and the positioning member 9. The extrusion part 311 is made of elastic material. The movement of the magnetic member 8 causes the extrusion part 311 to deform, and the space for accommodating air inside the cylinder body 31 becomes smaller, thereby increasing the pressure inside the cylinder body 31. After the pressure inside the cylinder body 31 increases to greater than the atmospheric pressure, the free end of the flap 32 tends to extend out of the cylinder body 31, but the free end of the flap 32 cannot extend out of the cylinder body 31 under the restriction of the end face of the magnetic member 8, but maintains a state in the air inlet 3111, that is, the closed state of the flap 32, at this time, the flap 32 realizes the closure of the air inlet 3111, preventing air from flowing out of the air inlet 3111; at the same time, the air in the cylinder body 31 tends to flow to a position with low pressure, so the air in the cylinder body 31 flows from the air outlet channel 312 of the cylinder body 31 to the outside of the cylinder body 31 to achieve external inflation. After reaching the preset time, the external chip control power supply is powered off, the coil 5 loses power, the reset member 7 restores elastic deformation, drives the magnetic member 8 to reset, and the magnetic member 8 drives the extrusion part 311 to reset. The space inside the cylinder body 31 for accommodating air increases, so that the pressure inside the cylinder body 31 is reduced accordingly. When the pressure inside the cylinder body 31 is lower than the atmospheric pressure, the free end of the flap 32 tilts toward the inside of the cylinder body 31, that is, it is in an open state. At this time, the air inlet 3111 of the cylinder body 31 is not closed. In this embodiment, the magnetic member 8 is provided with an air delivery groove 85, the air inlet end of the air delivery groove 85 is connected to the outside of the magnetic member 8, and the air outlet end of the air delivery groove 85 is connected to the air inlet 3111. Therefore, when the air inlet 3111 is not closed, air can enter the cylinder body 31 from the air delivery groove 85 of the magnetic member 8 through the air outlet, so as to realize the air storage inside the cylinder body 31. In this embodiment, air enters the air delivery groove 85 of the magnetic member 8 from the gap between the magnetic member 8 and the fixing frame 1. When the magnetic member 8 is reset, the shock absorbing pad 6 first contacts the fixing frame 1 because the shock absorbing pad 6 protrudes relative to the magnetic member 8. The shock absorbing pad 6 is made of soft material and can play a buffering role to prevent the magnetic member 8 from directly hitting the fixing frame 1 and causing damage.

[0048] Reference Figure 2 , Figure 3 , Figure 5 and Figure 6 In order to enable the cylinder body 31 to inflate outward through the air outlet pipe 22 of the fixed cover 2, it is necessary to enable the cylinder 3 to stably supply air to the fixed cover 2, and ensure the air tightness between the cylinder body 31 and the fixed cover 2 to prevent air from leaking from the connection between the cylinder body 31 and the fixed cover 2. In this embodiment, the fixed cover 2 receives the air flowing out of the air outlet channel 312 of the cylinder 3 body through the air chamber 23, and then discharges it through the air outlet pipe 22 connected to the air chamber 23. The opening of the air chamber 23 is set larger, which is convenient for inserting the air outlet channel 312 of the cylinder body 31 into the air chamber 23 during assembly to achieve the communication between the air chamber 23 and the air outlet channel 312. The peripheral connecting ear 33 of the cylinder body 31 is made of elastic material and is located on the periphery of the cylinder body 31. The connecting ear 33 covers the opening of the air chamber 23. After the fixed cover 2 and the fixed frame 4 clamp the connecting ear 33, the connecting ear 33 is tightly attached to the fixed cover 2 and the air chamber 23 opening is sealed. When the space for accommodating air in the cylinder body 31 is reduced and the air flows out from the air outlet channel 312, since the protrusion 24 extends into the interior of the cylinder body 31 through the air outlet channel 312 and the inner wall of the air outlet channel 312 contacts the outer surface of the protrusion 24, the air flows from between the protrusion 24 and the air outlet channel 312 to the air chamber 23, and then flows from the air chamber 23 to the air outlet pipe 22 of the fixed cover 2. After most of the air in the cylinder body 31 enters the air chamber 23, the pressure in the air chamber 23 is greater than the pressure in the cylinder body 31, so that the inner wall of the air outlet channel 312 is closely attached to the protrusion 24, preventing the air in the air chamber 23 from flowing back into the cylinder body 31.

[0049] Reference Figures 3 to 5 In the process of resetting the extrusion part 311, the air inlet 3111 will be deformed due to the deformation of the extrusion part 311. Therefore, in the process of changing the flap 32 from the open state to the closed state, the shape of the air inlet 3111 and the flap 32 may not fit well enough, resulting in the flap 32 being unable to fully enter the air inlet 3111. At this time, the air tightness of the air inlet 3111 is insufficient, and when the cylinder body 31 is exhausted outward, the air inlet 3111 will leak. Therefore, the extrusion part 311 can be further provided with a clearance groove 3112 connected to the air inlet 3111, and the sum of the area of ​​the clearance groove 3112 and the area of ​​the air inlet 3111 is slightly larger than the area of ​​the flap 32, so that the flap 32 will not be blocked by the hole wall of the air inlet 3111 when entering the air inlet 3111. In order to prevent air from leaking from the clearance groove 3112 , the end surface of the magnetic member 8 abuts against the extrusion portion 311 and covers the notch of the clearance groove 3112 , thereby achieving the closure of the clearance groove 3112 .

[0050] Embodiment 2

[0051] Reference Figure 7 and Figure 8 The difference between this embodiment and the first embodiment is that the air not only enters the air inlet groove 343 from the gap between the magnetic member 8 and the fixing frame 1 , but also enters the air inlet groove 343 from the air vent 13 on the fixing frame 1 .

[0052] Embodiment 3

[0053] Reference Fig. 9 and Fig.10 In this embodiment, the transmission connecting member 34 is provided with a slide groove 341, a limiting block 342 and an air inlet groove 343. The slide groove 341 is connected to the outside of the transmission connecting member 34 through the air inlet groove 343, the air inlet hole 3111 is connected to the slide groove 341, the magnetic member 8 is slidably connected to the slide groove 341, and the limiting block 342 is used to limit the magnetic member 8 from exiting the slide groove 341. When the air volume in the cylinder body 31 needs to be reduced, the end face of the magnetic member 8 abuts against the extrusion part 311. When the air volume in the cylinder body 31 needs to be increased, the magnetic member 8 slides in the slide groove 341 and separates from the extrusion part 311. After sliding a certain stroke, the magnetic member 8 is engaged with the limiting block 342. At this time, the air enters the interior of the cylinder body 31 through the air inlet groove 343, the slide groove 341 and the air inlet hole 3111 in sequence. In this embodiment, the magnetic member 8 can be provided with an air delivery groove 85 or not.

[0054] To ensure air tightness, when the air volume in the cylinder body 31 needs to be reduced, the side surface of the magnetic member 8 abuts against the groove wall of the slide groove 341 and closes the air inlet groove 343 , so that the slide groove 341 cannot be connected to the outside of the cylinder 3 through the air inlet groove 343 .

[0055] Embodiment 4

[0056] This embodiment discloses an electronic sphygmomanometer using the electromagnetic air pump in the first embodiment, wherein the electromagnetic air pump is used to inflate the arm cuff in the electronic sphygmomanometer.

[0057] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An electromagnetic air pump, characterized in that: The invention comprises a cylinder (3), a fixed frame (4), a coil (5), a shock-absorbing pad (6), and a reset member (7), a magnetic member (8), a positioning member (9) and a gasket (81) all arranged inside the fixed frame (4); the cylinder (3) comprises a cylinder body (31) and a flap (32); the cylinder body (31) is fixed relative to the fixed frame (4); the coil (5) is located on the outer periphery of the fixed frame (4); the coil (5) is used to drive the magnetic member (8) to move in a direction close to the cylinder body (31); and the reset member (7) is used to drive the magnetic member (8) to move in a direction away from the cylinder body (31); The flap (32) is made of an elastic material, the cylinder wall of the cylinder body (31) is provided with an extrusion portion (311), the extrusion portion (311) is made of an elastic material, the magnetic member (8) drives the extrusion portion (311) to deform so as to increase or decrease the volume of air in the cylinder body (31), the extrusion portion (311) is provided with an air inlet (3111) for allowing air outside the cylinder body (31) to enter the cylinder body (31), and the cylinder body (31) is provided with an air outlet channel (312) for allowing air inside the cylinder body (31) to flow out of the cylinder body (31); When the volume of air in the cylinder body (31) decreases, the flap (32) closes the air inlet hole (3111); when the volume of air in the cylinder body (31) increases, the interior of the cylinder body (31) communicates with the exterior of the cylinder body (31) through the air inlet hole (3111); A transmission block (82) is provided at one end of the magnetic member (8), a boss (83) and a limit block (84) are provided on the outer periphery of the other end of the magnetic member (8), and the end of the other end is connected to the shock-absorbing pad (6); the limit block (84) and the boss (83) are arranged in sequence in a direction away from the cylinder (3), and the cross-sectional area of ​​the limit block (84) is smaller than the cross-sectional area of ​​the boss (83), and the shock-absorbing pad (6) protrudes relative to the end surface of the magnetic member (8); the reset One end of the member (7) abuts against the positioning member (9), the end of the magnetic member (8) with a smaller cross-sectional area passes through the connecting hole of the gasket (81) and the through hole (91) of the positioning member (9) in sequence, the limit block (84) cannot pass through the through hole (91), and the other end of the reset member (7) abuts against the boss (83); the transmission connecting member (34) of the cylinder (3) is clamped with the transmission clamping block (82), and the end of the magnetic member (8) abuts against the extrusion portion (311).

2. An electromagnetic air pump according to claim 1, characterized in that: One end of the flap (32) is connected to the cylinder body (31), and the other end of the flap (32) is a free end; When the volume of air in the cylinder body (31) decreases, the end surface of the magnetic member (8) limits the movement of the free end of the flap (32).

3. An electromagnetic air pump according to claim 1, characterized in that: The magnetic component (8) is provided with an air delivery groove (85), the air inlet end of the air delivery groove (85) is in communication with the outside of the magnetic component (8), and the air outlet end of the air delivery groove (85) is in communication with the air inlet hole (3111).

4. The electromagnetic air pump according to claim 1, characterized in that: The extrusion portion (311) is provided with a clearance groove (3112) connected to the air inlet hole (3111), the flap (32) is located inside the air inlet hole (3111), and the end surface of the magnetic member (8) closes the clearance groove (3112) by contacting the extrusion portion (311).

5. The electromagnetic air pump according to claim 1, characterized in that: The cylinder (3) further comprises a transmission connecting member (34), the transmission connecting member (34) being connected to the extrusion portion (311), the magnetic member (8) being snap-fitted to the transmission connecting member (34), and the end surface of the magnetic member (8) being in contact with the extrusion portion (311).

6. The electromagnetic air pump according to claim 1, characterized in that: The electromagnetic air pump further comprises a fixed cover (2), wherein the fixed cover (2) is fixed relative to the fixed frame (4), and the cylinder (3) further comprises a connecting ear (33) connected to the cylinder body (31), wherein the fixed cover (2) and the fixed frame (4) clamp the connecting ear (33).

7. An electromagnetic air pump according to claim 6, characterized in that: The fixed cover (2) is provided with an air chamber (23), the air chamber (23) is provided with an opening for an air outlet passage (312) of the cylinder body (31) to extend into the interior of the air chamber (23), the connecting ear (33) is located on the outer periphery of the cylinder body (31), the connecting ear (33) is made of elastic material, and the connecting ear (33) is used to close the opening, and the fixed cover (2) is provided with an air outlet pipe (22) for allowing air inside the air chamber (23) to flow to the outside of the fixed cover (2).

8. An electromagnetic air pump according to claim 7, characterized in that: The inner wall of the air chamber (23) is provided with a protrusion (24), and the protrusion (24) extends into the interior of the cylinder body (31) through the air outlet channel (312), and the inner wall of the air outlet channel (312) abuts against the outer surface of the protrusion (24).

9. The electromagnetic air pump according to claim 6, characterized in that: The electromagnetic air pump comprises a fixing frame (1), and the fixing cover (2) and the fixing frame (4) are respectively connected to the fixing frame (1).

10. A sphygmomanometer, characterized in that: The electromagnetic air pump comprises the electromagnetic air pump as claimed in any one of claims 1 to 9.

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