Switch structure and medical equipment

Abstract

To provide a switch structure and a medical device that can improve durability.SOLUTION: A switch structure includes a circuit board having a tact key, and a flexible push button portion having a tact key pressing portion that presses the tact key and a board pressing portion arranged to press the circuit board when the tact key pressing portion presses the tact key. For example, the board pressing portions are arranged on both sides of the tact key pressing portion in a direction orthogonal to the pressing direction in which the tact key is pressed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a switch structure and a medical device. [Background technology]

[0002] Conventionally, a medical display device has been known that includes a housing with a front panel, a display unit and an operation switch arranged on the front panel, and in which pressing the operation switch establishes electrical contacts inside the housing to cause the display unit to display biological information.

[0003] In such medical display devices, it is required to ensure drip-proofness by, for example, discharging liquid that has entered the housing through the gap between the front panel and the operation switch to the outside of the housing without contacting electronic devices such as electrical contacts. Furthermore, it is preferable that the switch structure generates a clicking sensation to give the operator a sense of security that they have pressed the operation switch correctly.

[0004] As a switch structure that can ensure drip-proofness, for example, there is disclosed a switch structure that has electrical contacts arranged on a circuit board, contact rubber arranged along the circuit board, a dome-shaped elastically deformable rubber dome portion formed on the contact rubber to cover the electrical contacts, an operator formed integrally with the rubber dome portion, and a contact piece attached to the underside of the operator and pressing against the electrical contacts, and the rubber dome portion covers the electrical contacts, thereby ensuring drip-proofness (see, for example, Patent Document 1).

[0005] Furthermore, as a switch structure that can provide a clicking sensation, for example, a switch structure has been disclosed that has a tactile key (tactile switch) arranged on a circuit board, an elastically deforming portion that forms a skirt shape to cover the tactile key, and a tactile key pressing portion that is formed integrally with the elastically deforming portion and presses the tactile key, and when the tactile key is pressed, the skirt-shaped elastically deforming portion bends and rebounds, providing a clicking sensation (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-009782 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-216609 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the switch structure described in Patent Document 1, when pressing the electrical contacts, the pressing force is applied in a concentrated manner to the contact pieces and the electrical contacts, which may cause the pressing force to exceed the load-bearing limit of the electrical contacts, resulting in a problem of reduced durability of the contact pieces and the electrical contacts.

[0008] Furthermore, in the switch structure described in Patent Document 2, when a tact key is pressed, the pressing force is concentrated on the tact key pressing portion and the tact key, which can result in an excessive load that exceeds the load-bearing capacity of the tact key, resulting in a problem of reduced durability of the tact key pressing portion and the tact key.

[0009] An object of the present invention is to provide a switch structure and a medical device that can improve durability. [Means for solving the problem]

[0010] In order to achieve the above object, the switch structure of the present invention comprises: a circuit board having a tact key; a flexible push button unit having a tact key pressing unit that presses the tact key and a board pressing unit that is arranged to press the circuit board when the tact key pressing unit presses the tact key; a skirt portion that is formed integrally with the push button portion, spreads out in a skirt shape so as to cover the tact key together with the push button portion, and biases the push button portion, when pressed in a direction to press the tact key, in a direction opposite to the pressing direction; Equipped with picture, The bottom of the skirt portion has a communication hole that communicates the inside and outside of a first closed space closed by the push button portion, the skirt portion, and the circuit board. .

[0011] The medical device of the present invention comprises: The switch structure is as described above. [Effects of the Invention]

[0012] According to the present invention, durability can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing the appearance of a medical display device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the front panel of the medical display device according to the embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing an XZ cross section of the switch structure. [Figure 4] FIG. 2 is a cross-sectional view showing a YZ cross section of the switch structure. [Figure 5] FIG. 10 is a view of the push button portion as seen from the rear side. [Figure 6] FIG. 3 is a cross-sectional view showing the XZ cross section of the push button portion. [Figure 7] FIG. 3 is a cross-sectional view showing the YZ cross section of the push button portion. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a medical display device according to an embodiment of the present invention. FIG. 1 depicts an X-axis, a Y-axis, and a Z-axis. In FIG. 1, the direction from the lower left to the upper right is referred to as the X-direction, left-right direction, or both-side direction, the upper right direction is referred to as the "+X-direction" or right side, and the lower left direction is referred to as the "-X-direction" or left side. In FIG. 1, the up-down direction is referred to as the Y-direction or up-down direction, the upper direction is referred to as the "+Y-direction" or upper side, and the lower direction is referred to as the "-Y-direction" or lower side. In FIG. 1, the direction from the lower right to the upper left is referred to as the Z-direction or depth direction, the lower right direction is referred to as the "+Z-direction" or front side, and the upper left direction is referred to as the "-Z-direction" or back side.

[0015] The medical display device 1 shown in FIG. 1 is, for example, a biological information monitor (also called a bedside monitor) that measures and displays biological information such as a patient's heart rate and blood pressure in a hospital room or operating room. The medical display device 1 includes a main body 10. The main body 10 has a display 11, an external input terminal group 12, a housing 20, and a push button group 30 (operation switch). The housing 20 houses a control module, a circuit board for a measurement module, etc., and a battery. The display group 11 is, for example, a touch panel type liquid crystal display panel that displays biological information. The external input terminal group 12 has various connectors for connecting a measurement unit such as a cuff. The push button group 30 is, for example, a power standby switch (auxiliary power switch).

[0016] The housing 20 includes a main body case 21 and a front panel 22. The main body case 21 houses the circuit board and battery. The front panel 22 is disposed on the front side (+Z direction) of the main body case 21. The display unit 11 is attached to the front side of the front panel 22. The main body case 21 and the front panel 22 are each made of a thermoplastic resin, such as a mixture of PC resin (polycarbonate resin) and ABS resin (acrylonitrile, butadiene, styrene copolymer synthetic resin).

[0017] Fig. 2 is a front view of the front panel of the medical display device. As shown in Fig. 1 and Fig. 2, the front panel 22 has a rectangular peripheral edge 23. The peripheral edge 23 is composed of a left edge 23A, a right edge 23B, an upper edge 23C, and a lower edge 23D located on the left (-X direction), right (+X direction), upper (+Y direction), and lower (-Y direction) sides of the rectangular center.

[0018] FIG. 3 is a cross-sectional view showing an XZ cross section of the switch structure. FIG. 4 is a cross-sectional view showing a YZ cross section of the switch structure. As shown in FIGS. 3 and 4, a circuit board 25 having tact keys 26 is disposed on the rear side (-Z direction) of a lower edge 23D of the front panel 22. The circuit board 25 is fixed to the lower edge 23D with screws. The lower edge 23D has a cylindrical hole 22A that is disposed opposite the position of the tact keys 26 and penetrates in the depth direction (Z direction). The cylindrical hole 22A has a peripheral wall portion 22B that extends from an opening peripheral edge 22C thereof toward the rear side (-Z direction). The front end of the peripheral wall portion 22B (on the front side) (+Z direction) is continuous with the opening peripheral edge 22C of the cylindrical hole 22A.

[0019] 3 and 4, the switch structure 3 includes a front panel 22, a circuit board 25, a push button portion 30, and an elastic deformation portion 33. The push button portion 30 and the elastic deformation portion 33 are each made of a material such as silicone rubber.

[0020] FIG. 5 is an arrow view of the push button unit as seen from the rear side. FIG. 6 is a cross-sectional view showing the XZ cross section of the push button unit. FIG. 7 is a cross-sectional view showing the YZ cross section of the push button unit. As shown in FIG. 5, the push button unit 30 is formed in an elliptical cylindrical shape with the long axis direction in the left-right direction (X direction). As shown in FIGS. 6 and 7, the push button unit 30 has an elliptical cylindrical portion 31 whose axis of the elliptical cylindrical shape extends in the depth direction (Z direction). As shown in FIGS. 3 and 4, the elliptical cylindrical portion 31 is disposed closer to the user (in the +Z direction) than the tact key 26. The elliptical cylindrical portion 31 is inserted into the cylindrical hole 22A. The front end (in the +Z direction) of the elliptical cylindrical portion 31 is surrounded by the opening peripheral portion 22C of the cylindrical hole 22A and coincides with the opening peripheral portion 22C in the depth direction (Z direction).

[0021] 5, 6, and 7, the rear end (-Z direction) of the elliptical columnar portion 31 has a tact key pressing portion 37 and a board pressing portion 38. The rear end (-Z direction) of the elliptical columnar portion 31 has a circumferential groove 32 that surrounds the tact key pressing portion 37. The groove depth direction of the circumferential groove 32 is the depth direction (Z direction), and the groove depth from the rear end face is set to, for example, 5.0 mm.

[0022] As shown in FIGS. 3 to 7, the tact key pressing portion 37 is separated from other portions of the elliptical columnar portion 31 (including the board pressing portion 38) by the circumferential groove 32. The tact key pressing portion 37 is disposed in the center of the major axis direction (X direction) of the elliptical columnar shape so as to face the tact key 26 in the depth direction (Z direction). As a result, when the push button portion 30 is pressed toward the depth side (-Z direction), the tact key pressing portion 37 presses the tact key 26. Hereinafter, the depth side (-Z direction) will be referred to as the "pressing direction." The XY cross section of the tact key pressing portion 37 has an elliptical shape. The depth end face of the tact key pressing portion 37 is a plane perpendicular to the depth direction (Z direction). The gap between the depth end face of the tact key pressing portion 37 and the tact key 26 is set to, for example, 0.2 mm. The amount of movement of the tact key 26 is set to, for example, 0.2 mm.

[0023] As shown in FIG. 5, the board pressing portions 38 are disposed on the right (+X direction) and left (-X direction) of the tact key pressing portion 37 in the major axis direction (X direction) of the elliptical cylindrical shape. The board pressing portions 38 are separated from the tact key pressing portion 37 by the circumferential groove 32, but are formed continuously with the rest of the elliptical cylindrical portion 31. The XY cross section of the board pressing portion 38 disposed on the right side of the tact key pressing portion 37 is shaped like the right half of the ellipse. The XY cross section of the board pressing portion 38 disposed on the left side of the tact key pressing portion 37 is shaped like the left half of the ellipse. As shown in FIGS. 3 and 6, the right and left board pressing portions 38 each taper toward the rear (+Z direction). The rear end surfaces of the right and left board pressing portions 38 are flat surfaces perpendicular to the depth direction (Z direction). The gap between the rear end faces of the right and left board pressing portions 38 and the circuit board 25 is set to, for example, 1.0 mm based on experiments and simulations to obtain a tactile feel. Thus, if the tact key 26 moves 0.2 mm toward the rear (-Z direction), i.e., if the tact key pressing portion 37 and the board pressing portion 38 each move 0.4 mm toward the rear (-Z direction), the gap between the rear end faces of the board pressing portions 38 and the circuit board 25 becomes 0.6 mm, which is the difference between the 0.4 mm and the 1.0 mm gap. If the board pressing portion 38 moves further toward the rear (-Z direction) by (0.6 + α) mm (where α > 0) from this state, the board pressing portion 38 presses the circuit board 25. In other words, the deflection of the board pressing portion 38 is α mm. At this time, the tact key pressing portion 37 also moves (0.6+α) mm and presses the tact key 26. In other words, the deflection of the tact key pressing portion 37 is (0.6+α) mm. If the total length of the tact key pressing portion 37 in the depth direction (Z direction) and the total length of the board pressing portion 38 in the depth direction (Z direction) are equal (total length = L), the strain of the tact key pressing portion 37 is (0.6+α) / L, and the strain of the board pressing portion 38 is α / L. Therefore, the strain of the tact key pressing portion 37 is greater than the strain of the board pressing portion 38.In addition, by distributing the operating force applied to the push button portion 30 into a pressing force that presses the tact key 26 via the tact key pressing portion 37 and a pressing force that presses the circuit board 25 via the board pressing portion 38, the tact key pressing portion 37 and the board pressing portion 38 may begin to deflect simultaneously in order to prevent the pressing force that presses the tact key 26 from becoming an excessive load that exceeds the load-bearing capacity of the tact key 26.Furthermore, since it is sufficient that the tact key pressing portion 37 deflects to a certain extent before the board pressing portion 38 deflects, the distortion of the tact key pressing portion 37 only needs to be greater than the distortion of the board pressing portion 38.

[0024] As shown in FIGS. 3 to 7, the elastic deformation portion 33 is formed integrally with the push button portion 30. The elastic deformation portion 33 has a skirt portion 34 that spreads out in a skirt-like shape toward the rear side (-Z direction) so as to cover the tactile key 26 from the front side (+Z direction) together with the elliptical columnar portion 31. When the push button portion 30 is pressed toward the rear side (-Z direction), the skirt portion 34 bends against a restoring force and rebounds due to the restoring force. As a result, the elastic deformation portion 33 biases the push button portion 30 pressed toward the rear side (-Z direction) toward the front side (+Z direction). The thickness of the skirt portion 34 is set to, for example, 0.5 mm based on experiments and simulations in order to obtain a clicking sensation.

[0025] A waist portion 34a of the skirt portion 34 is connected to the rear end of the peripheral wall portion of the elliptical columnar portion 31. A bottom portion 35 of the skirt portion 34 has a sealing portion 36 arranged to close a gap S1 (see FIGS. 3 and 4) between the peripheral wall portion 22B of the cylindrical hole 22A and the circuit board 25. As shown in FIGS. 3, 4, and 5, the sealing portion 36 has an elliptical outer shape with its major axis in the left-right direction (X direction) and a thickness in the depth direction (Z direction).

[0026] As shown in FIGS. 3 and 4, the thickness of the seal portion 36 in the depth direction (Z direction) is set to be thicker than the width of the gap S1. As a result, the seal portion 36 is sandwiched and compressed by the peripheral wall portion 22B and the circuit board 25 from both sides in the depth direction (Z direction), and thus adheres closely to the rear end of the peripheral wall portion 22B and the circuit board 25. The seal portion 36 adheres closely to the rear end of the peripheral wall portion 22B, forming a closed space 40A between the peripheral wall portion 22B and the elliptical columnar portion 31. The lower (-Y direction) wall portion of the peripheral wall portion 22B has a drain hole 22D (see FIG. 4). Liquid may penetrate into the closed space 40A through the gap between the elliptical columnar portion 31 and the opening periphery 22C of the cylindrical hole 22A. In this case, the infiltrated liquid falls downward within the closed space 40A. That is, the liquid collects on the lower wall portion of the peripheral wall portion 22B. The collected liquid is discharged to the outside of the closed space 40A through the drain hole 22D.

[0027] Furthermore, the seal portion 36 closes the gap S1, thereby forming a closed space 40B enclosed by the elliptical columnar portion 31, the skirt portion 34, and the circuit board 25. As shown in FIGS. 4 and 5, a communication hole 36a that communicates the inside and outside of the closed space 40B is disposed between the seal portion 36 and the circuit board 25. The communication hole 36a is disposed at the center of the elliptical shape in the left-right direction (X direction) and at both ends in the up-down direction (Y direction). The communication hole 36a is formed by recessing the surface of the seal portion 36 on the rear side (-Z direction) that contacts the circuit board 25 toward the front side (+Z direction). The provision of the communication hole 36a prevents a pressure difference from occurring between the inside and outside of the closed space 40B. Furthermore, since the closed space 40B is separated from the closed space 40A by the skirt portion 34, the liquid inside the closed space 40A does not infiltrate into the closed space 40B, nor does it infiltrate into the closed space 40B through the communicating hole 36a.

[0028] The switch structure 3 according to the above embodiment includes a circuit board 25 having a tact key 26, a tact key pressing portion 37 that presses the tact key 26, and a push button portion 30 having a board pressing portion 38 that is arranged to press the circuit board 25 when the tact key pressing portion 37 presses the tact key 26.

[0029] According to the above configuration, the operating force applied to the push button portion 30 is dispersed into a pressing force that presses the tact key 26 via the tact key pressing portion 37 and a pressing force that presses the circuit board 25 via the board pressing portion 38. This prevents the pressing force that presses the tact key 26 from becoming an excessive load that exceeds the load capacity of the tact key 26, for example, and therefore makes it possible to improve the durability of the switch structure 3.

[0030] Furthermore, in the switch structure 3 according to the above embodiment, the board pressing portions 38 are arranged on both sides of the tact key pressing portion 37 in a direction perpendicular to the pressing direction (-Z direction). When the push button portion 30 is operated, the push button portion 30 may move in a direction oblique to the pressing direction (-Z direction). However, in this case, the tact key pressing portion 37 presses the tact key 26, and the board pressing portion 38 arranged on at least one side of the tact key pressing portion 37 presses the circuit board 25. As a result, the operating force applied to the push button portion 30 is distributed between a pressing force that presses the tact key 26 and a pressing force that presses the circuit board 25, thereby improving the durability of the switch structure 3.

[0031] In the switch structure 3 according to the above embodiment, the push button unit 30 has an elliptical cylindrical portion 31 formed in an elliptical cylindrical shape, with the axis of the elliptical cylindrical shape extending in the pressing direction (-Z direction). The tact key pressing portion 37 and the board pressing portion 38 are each disposed at the end of the elliptical cylindrical portion 31 in the pressing direction. The board pressing portions 38 are disposed on both sides of the tact key pressing portion 37 in the major axis direction of the elliptical cylindrical shape. When the push button unit 30 is operated, it is preferable to press the center of the elliptical cylindrical portion in the major axis direction, but there are also cases where an end of the elliptical cylindrical portion in the major axis direction is pressed. In this case, the elliptical cylindrical portion moves in a direction oblique to the pressing direction. However, even in this case, the tact key pressing portion 37 presses the tact key 26, and the board pressing portion 38, disposed on at least one side of the tact key pressing portion 37 in the major axis direction, presses the circuit board 25. As a result, the operating force applied to the push button portion 30 is dispersed into a pressing force that presses the tact key 26 and a pressing force that presses the circuit board 25. As a result, the durability of the switch structure 3 can be improved.

[0032] Furthermore, in the switch structure 3 according to the above embodiment, the elliptical columnar portion 31 has a circumferential groove 32 that surrounds the tact key pressing portion 37. The circumferential groove 32 separates the tact key pressing portion 37 from the board pressing portion 38 that is disposed around the tact key pressing portion 37. As a result, even if the board pressing portion 38 is deflected by a reaction force from the circuit board 25, the tact key pressing portion 37 is not affected by the deflection of the board pressing portion 38. Furthermore, even if the tact key pressing portion 37 is deflected by a reaction force from the tact key 26, the board pressing portion 38 is not affected by the deflection of the tact key pressing portion 37. This makes it easy to set a gap between the board pressing portion 38 and the circuit board 25, for example, to obtain a clicking sensation or to improve durability.

[0033] Furthermore, in the switch structure 3 according to the above embodiment, the elastic deformation portion 33 has a skirt portion 34 that spreads out in a skirt shape so as to cover the tact key 26 together with the elliptical columnar portion 31. Furthermore, a bottom portion 35 of the skirt portion 34 has a seal portion 36 that is arranged to close a gap S1 between the peripheral wall portion 22B of the cylindrical hole 22A and the circuit board 25. As a result, even if liquid seeps in through a gap between the opening periphery 22C of the cylindrical hole 22A and the elliptical columnar portion 31, the tact key 26 is covered by the skirt portion 34 and the elliptical columnar portion 31, and the gap S1 between the peripheral wall portion 22B of the cylindrical hole 22A and the circuit board 25 is closed by the seal portion 36, so that the drip-proof properties of the tact key 26 can be ensured.

[0034] Furthermore, in the switch structure 3 according to the above embodiment, a communication hole 36a that communicates the inside and outside of the closed space 40B enclosed by the elliptical columnar portion 31, the skirt portion 34, and the circuit board 25 is disposed between the seal portion 36 and the circuit board 25. The provision of the communication hole 36a prevents a pressure difference from occurring between the inside and outside of the closed space 40B. As a result, the skirt portion 34 bends and rebounds without being affected by the pressure difference, making it possible to obtain a sufficient clicking sensation.

[0035] Furthermore, in the switch structure 3 according to the above embodiment, the board pressing portions 38 disposed on the right and left sides of the tact key pressing portion 37 are tapered toward the rear (+Z direction). This makes it gradually more difficult for the board pressing portion 38 to bend when it presses the circuit board 25. As a result, in the initial stage in which the operating force applied to the push button portion 30 is distributed between a pressing force that presses the tact key 26 via the tact key pressing portion 37 and a pressing force that presses the circuit board 25 via the board pressing portion 38, the board pressing portion 38 can share a smaller proportion of the operating force than the tact key pressing portion 37. Therefore, the operating force does not increase suddenly, and operability is not impaired. Meanwhile, in the final stage in which the operating force is distributed, the board pressing portion 38 can share a larger proportion of the operating force than the tact key pressing portion 37. Therefore, since the pressing force applied to the tact key 26 is prevented from becoming an excessive load that exceeds the load capacity of the tact key 26, the durability of the switch structure 3 can be further improved.

[0036] In the switch structure 3 according to the above embodiment, the communication hole 36a is formed by recessing the rear side (-Z direction) surface of the seal portion 36 that contacts the circuit board 25 toward the front side (+Z direction). However, the present invention is not limited to this, and the communication hole 36a may be formed, for example, by recessing the front side (+Z direction) surface of the circuit board 25 that contacts the seal portion 36 toward the rear side (-Z direction). For example, the communication hole 36a may be recessed by forming a through hole in the circuit board 25.

[0037] Furthermore, in the switch structure 3 according to the above embodiment, the present invention has been described as being applied to a vital sign monitor, but the present invention is not limited to this and is effective when widely applied to, for example, medical equipment. In particular, medical equipment requires drip-proofness and durability, making the switch structure of the present invention extremely effective.

[0038] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be carried out in various forms without departing from the gist or main features thereof. [Industrial Applicability]

[0039] The present invention is suitably used in medical equipment having a switch structure that requires improved durability. [Explanation of symbols]

[0040] 1 Medical display device 3 Switch Structure 10 Main body 11 Display section 12 External input terminals 20 Case 21 Main unit case 22 Front Panel 22A cylindrical hole 22B Peripheral wall part 22C Opening edge 22D Drain hole 23 Periphery 23A Left edge 23B Right edge 23C Upper edge 23D lower edge 25 Circuit Board 26 Tact Key 30 Push button (operation switch) 31 Elliptical cylindrical section 32 Circumferential groove 33 Elastic deformation part 34 Skirt Club 34a Lumbar region 35 Hem 36 Seal part 36a Communication hole 37 Tactile key pressing part 38 Board pressing part 40A,40B Closed space

Claims

1. a circuit board having a tact key; a flexible push button unit having a tact key pressing unit that presses the tact key and a board pressing unit that is arranged to press the circuit board when the tact key pressing unit presses the tact key; a skirt portion that is formed integrally with the push button portion, spreads out in a skirt shape so as to cover the tact key together with the push button portion, and biases the push button portion, when pressed in a direction to press the tact key, in a direction opposite to the pressing direction; Equipped with a bottom portion of the skirt portion has a communication hole that communicates the inside and outside of a first closed space closed by the push button portion, the skirt portion, and the circuit board; Switch structure.

2. When the tact key pressing portion presses the tact key and the board pressing portion presses the circuit board, the strain of the tact key pressing portion is configured to be equal to or greater than the strain of the board pressing portion. The switch structure according to claim 1 .

3. the board pressing portions are disposed on both sides of the tact key pressing portion in a direction perpendicular to a pressing direction in which the tact key is pressed; The switch structure according to claim 1 or 2.

4. the push button portion has an elliptical cylindrical portion formed in an elliptical cylindrical shape, the cylindrical axis of the elliptical cylindrical shape extending in the pressing direction, the tact key pressing portion and the board pressing portion are each disposed at an end of the elliptical columnar portion in the pressing direction, the board pressing portions are disposed on both sides of the tact key pressing portion in the major axis direction of the elliptical cylindrical shape; The switch structure according to claim 3 .

5. a panel having a cylindrical hole through which the elliptical columnar portion is inserted and which is positioned opposite the position of the tact key; a bottom portion of the skirt portion having a sealing portion disposed to close a gap between a peripheral wall portion of the cylindrical hole and the circuit board; The switch structure according to claim 4 .

6. The peripheral wall portion of the cylindrical hole has a drain hole that can discharge liquid that penetrates into the second closed space enclosed between the peripheral wall portion and the elliptical cylindrical portion to the outside of the second closed space. The switch structure according to claim 5 .

7. A circuit board having a tact key; a flexible push button unit having a tact key pressing unit that presses the tact key and a board pressing unit that is arranged to press the circuit board when the tact key pressing unit presses the tact key; Equipped with the board pressing portions are arranged on both sides of the tact key pressing portion in a direction perpendicular to a pressing direction in which the tact key is pressed, the push button portion has an elliptical cylindrical portion formed in an elliptical cylindrical shape, the cylindrical axis of the elliptical cylindrical shape extending in the pressing direction, the tact key pressing portion and the board pressing portion are each disposed at an end of the elliptical columnar portion in the pressing direction, the board pressing portions are disposed on both sides of the tact key pressing portion in the major axis direction of the elliptical cylindrical shape, The push button may further include an elastic deformation portion that is integrally formed with the push button portion and biases the push button portion, when pressed in the pressing direction, in a direction opposite to the pressing direction, the elastic deformation portion has a skirt portion that spreads out in a skirt shape so as to cover the tact key together with the elliptical columnar portion, a panel having a cylindrical hole through which the elliptical columnar portion is inserted and which is positioned opposite the position of the tact key; a bottom portion of the skirt portion has a sealing portion arranged to close a gap between a peripheral wall portion of the cylindrical hole and the circuit board, a communication hole is disposed between the seal portion and the circuit board, the communication hole communicating the inside and outside of a closed space enclosed by the elliptical cylindrical portion, the skirt portion, and the circuit board; Switch structure.

8. A medical device comprising the switch structure according to any one of claims 1 to 7.

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