Oral cleaning device and its nozzle

Abstract

To provide a mouth washing device and its nozzle with high added value. [Solution] The oral cleaning device includes a nozzle (40) including a flow path configuration unit (50) with a flow path (FP) including an inlet and an outlet (41A), and a pump that supplies cleaning liquid to the inlet so that the flow rate of the cleaning liquid sprayed from the outlet (41A) is in the range of 200 to 350 mL / min. The flow path configuration unit (50) includes a first configuration unit (51) including a first flow path (FP1) that configures the flow path (FP), a contraction section (53) located downstream of the first configuration unit (51) that narrows the flow path (FP), and a second configuration unit (52) located downstream of the contraction section (53) that includes a second flow path (FP2) that widens from the contraction section (53) toward the outlet (41A). The first configuration unit (51), the contraction section (53), and the second configuration unit (52) are configured so that cavitation occurs in the cleaning liquid flowing through the flow path (FP) when the flow rate of the cleaning liquid sprayed from the outlet (41A) is in the range of 200 to 350 mL / min.

Description

Technical Field

[0001] The present invention relates to an oral cleaning device for cleaning the oral cavity with a cleaning liquid and a nozzle thereof.

Background Art

[0002] As an example of a conventional oral cleaning device, there is known an oral cleaning device including a nozzle including a flow path component provided with an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is injected, and a pump for supplying the cleaning liquid to the inlet. Patent Document 1 discloses an example of a conventional oral cleaning device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the conventional oral cleaning device, although a certain level has been reached in removing dirt in the oral cavity, there is still room for further consideration in terms of enhancing added value.

Means for Solving the Problems

[0005] One form of the oral cavity cleaning device according to the present invention includes a nozzle including a flow path component provided with a flow path including an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is ejected, and a pump that supplies the cleaning liquid to the inlet so that the flow rate of the cleaning liquid ejected from the outlet is included in the range of 200 to 350 mL / min. The flow path component includes a first component including a first flow path that constitutes the flow path, a narrowing portion provided on the downstream side of the first component that narrows the flow path, and a second component provided on the downstream side of the narrowing portion and including a second flow path that widens from the narrowing portion side toward the outlet side. The first component, the narrowing portion, and the second component are configured such that cavitation occurs in the cleaning liquid flowing through the flow path when the flow rate of the cleaning liquid ejected from the outlet is included in the range of 200 to 350 mL / min.

Effect of the Invention

[0006] The oral cavity cleaning device and its nozzle according to the present invention have high added value.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] (An example of a form that an oral cavity cleaning device and its nozzle can take) [1] One form of the oral cavity cleaning device according to the present invention includes a nozzle including a flow path component provided with a flow path including an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is ejected, and a pump that supplies the cleaning liquid to the inlet so that the flow rate of the cleaning liquid ejected from the outlet is included in the range of 200 to 350 mL / min. The flow path component includes a first component including a first flow path that constitutes the flow path, a reduction part provided on the downstream side of the first component that narrows the flow path, and a second component provided on the downstream side of the reduction part and including a second flow path that widens from the reduction part side toward the outlet side. The first component, the reduction part, and the second component are configured such that cavitation occurs in the cleaning liquid flowing through the flow path when the flow rate of the cleaning liquid ejected from the outlet is included in the range of 200 to 350 mL / min.

[0009] An oral cavity cleaning device that ejects a cleaning liquid from a nozzle can remove stubborn tooth stains that are difficult to remove. Tooth stains are mainly food residues. According to conventional oral cavity cleaning devices, food residues can be appropriately removed, but it is difficult to obtain an effect for removing stubborn stains such as dental plaque that adheres firmly to teeth. To solve such problems, for example, Japanese Patent Application Laid-Open No. 62-213752 (hereinafter referred to as "Prior Art Document 1") proposes a technique of generating cavitation in a nozzle and ejecting a cleaning liquid containing bubbles generated by cavitation (hereinafter referred to as "cavitation bubbles") from the nozzle. When a cleaning liquid containing cavitation bubbles is ejected into the oral cavity, stubborn stains such as dental plaque can be easily removed by the impact accompanying the rupture of the cavitation bubbles. Japanese Patent Publication No. 2015-503382 (hereinafter referred to as "Prior Art Document 2") discloses the dimensions of a nozzle including a structure for generating cavitation.

[0010] Regarding removing stubborn dirt by injecting a cleaning liquid containing cavitation bubbles from a nozzle, the cleaning ability of the oral cleaning device can be enhanced. However, when considering the influence of the oral cleaning device on the oral cavity from a broader perspective, properly removing food residues and making the user feel comfortable when the cleaning liquid is injected into the oral cavity are also important factors in an oral cleaning device. The flow rate of the cleaning liquid injected from the nozzle affects the removal of food residues and the sensation given to the user. Therefore, in order to realize an oral cleaning device having the performance of properly removing food residues, the performance of making the user feel comfortable, and the performance of removing stubborn dirt, not only the dimensions of the nozzle including the structure for generating cavitation but also the flow rate of the cleaning liquid injected from the nozzle need to be considered. However, neither of Prior Arts 1 and 2 mentions the flow rate of the cleaning liquid injected from the nozzle. Also, some of the dimensions disclosed in Prior Art 2 are considered to include values at which cavitation does not occur. Thus, in the field related to conventional oral cleaning devices, there is no idea of realizing an oral cleaning device having the performance of properly removing food residues, the performance of making the user feel comfortable, and the performance of removing stubborn dirt.

[0011] Based on the background of such conventional oral cleaning devices, the inventor of the present application considered an oral cleaning device with more preferable performance and invented an oral cleaning device according to the present invention. The oral cleaning device according to the present invention includes a pump that supplies a cleaning liquid to the inlet of a nozzle such that the flow rate of the cleaning liquid ejected from the outlet of the nozzle is included in the range of 200 to 350 mL / min. From the results of tests and the like, it has been confirmed that when the flow rate of the cleaning liquid ejected from the nozzle is included in the range of 200 to 350 mL / min, the cleaning liquid ejected into the oral cavity appropriately removes food residues and gives the user a comfortable feeling. Therefore, the oral cleaning device according to the present invention has the performance of appropriately removing food residues and the performance of giving the user comfort. The oral cleaning device according to the present invention further includes a first component, a constriction portion, and a second component configured such that cavitation occurs in the cleaning liquid when the flow rate of the cleaning liquid ejected from the outlet of the nozzle is included in the range of 200 to 350 mL / min. For this reason, the cleaning liquid capable of appropriately removing food residues and giving the user comfort further contains cavitation bubbles. Thus, the oral cleaning device according to the present invention further has the performance of removing stubborn stains in addition to the performance of appropriately removing food residues and the performance of giving the user comfort. Thereby, the added value of the oral cleaning device is increased.

[0012] 〔2〕According to an example of the oral cleaning device, the constriction portion includes a first wall surface and a second wall surface that face each other across the center line in a cross-section of the nozzle along the center line of the flow path, and a first tangent that is a tangent to the first wall surface representing the degree of inclination of the first wall surface with respect to the center line in the cross-section of the nozzle, and a second tangent that is a tangent to the second wall surface representing the degree of inclination of the second wall surface with respect to the center line in the cross-section of the nozzle form an angle included in the range of 120 to 135°.

[0013] When the angle formed by the first tangent and the second tangent is included in the range of 120 to 135°, it has been confirmed by tests that the cleaning liquid contains a sufficient amount of cavitation bubbles to sufficiently remove stains in the oral cavity.

[0014] 〔3〕According to an example of the oral cleaning device, in the cross-section of the nozzle along the center line of the flow path, the second component includes a third wall surface and a fourth wall surface that face each other across the center line. The angle formed by a third tangent, which is a tangent to the third wall surface representing the degree of inclination of the third wall surface with respect to the center line in the cross-section of the nozzle, and a fourth tangent, which is a tangent to the fourth wall surface representing the degree of inclination of the fourth wall surface with respect to the center line in the cross-section of the nozzle, is included in the range of 5.5 to 6.5°.

[0015] When the angle formed by the third tangent and the fourth tangent is included in the range of 5.5 to 6.5°, it has been confirmed by tests that the cleaning liquid contains a sufficient amount of cavitation bubbles to sufficiently remove dirt in the oral cavity.

[0016] 〔4〕According to an example of the oral cleaning device, the cross-sectional shape of the flow path of the constriction in the cross-section perpendicular to the center line of the flow path is circular, and the inner diameter of the flow path of the small-diameter part, which is the part closest to the outlet side in the constriction, is included in the range of 0.80 to 0.85 mm.

[0017] When the inner diameter of the flow path of the small-diameter part is included in the range of 0.80 to 0.85 mm, it has been confirmed by tests that the cleaning effect of the oral cleaning device is enhanced. This is presumably related to the increase in the amount of cavitation bubbles contained in the cleaning liquid supplied into the oral cavity.

[0018] 〔5〕According to an example of the oral cleaning device, the second component is formed in the range from the constriction to the outlet, and the length of the second component in the direction along the center line of the flow path is included in the range of 8.5 to 10.0 mm.

[0019] When the length of the second component is included in the range of 8.5 to 10.0 mm, it has been confirmed by tests that the cleaning effect of the oral cleaning device is enhanced. This is presumably related to the increase in the amount of cavitation bubbles contained in the cleaning liquid supplied into the oral cavity.

[0020] [6] One form of the nozzle of the oral cavity cleaning device according to the present invention is the nozzle of the oral cavity cleaning device described in any one of [1] to [5] above. According to the nozzle of the oral cavity cleaning device, substantially the same effects as those obtained by the oral cavity cleaning devices of [1] to [5] above can be obtained.

[0021] (Embodiment) The oral cavity cleaning device 1 shown in FIG. 1 is used for cleaning the oral cavity, and mainly for cleaning teeth and gums in the oral cavity. The oral cavity cleaning device 1 is installed and used on a flat installation surface such as a washstand (not shown). The oral cavity cleaning device 1 is driven by electric power supplied from an external power source (not shown) such as a commercial power source, and injects a cleaning liquid into the oral cavity. An example of the cleaning liquid is tap water mixed with a cleaning agent, or tap water.

[0022] The oral cavity cleaning device 1 includes a main body unit 10, a tube 20, and a cleaning unit 30. The main body unit 10 includes a device main body 11 and a tank 16. The function of the tank 16 is to store the cleaning liquid. The tank 16 is detachably provided on the device main body 11, for example. The device main body 11 houses various elements for driving the oral cavity cleaning device 1. The device main body 11 includes a housing 12, a pump 13, a motor 14, a power supply unit 15, and an operation unit (not shown). The pump 13, the motor 14, and the power supply unit 15 are housed in the housing 12. The function of the operation unit is to switch on and off the power supply of the oral cavity cleaning device 1. The operation unit is provided on the housing 12, for example.

[0023] The function of the pump 13 is to discharge the cleaning liquid stored in the tank 16. An example of the pump 13 is a piston pump. The apparatus main body 11 further includes an upstream channel 17A and a downstream channel 17B. The upstream channel 17A communicates the suction port 13A of the pump 13 and the tank 16 so that the cleaning liquid can flow through. The downstream channel 17B communicates the discharge port 13B of the pump 13 and the tube 20 so that the cleaning liquid can flow through. In one example, the pump 13 draws the cleaning liquid flowing through the upstream channel 17A from the suction port 13A and discharges the cleaning liquid from the discharge port 13B into the downstream channel 17B. A check valve (not shown) may be provided in the downstream channel 17B so that the cleaning liquid flowing through the downstream channel 17B is supplied to the tube 20. The function of the motor 14 is to drive the pump 13. The function of the power supply unit 15 is to supply power to the motor 14. In one example, by connecting a power cord (not shown) provided on the apparatus main body 11 to an external power source, the power of the external power source is supplied to the power supply unit 15.

[0024] The tube 20 connects the main body unit 10 and the cleaning unit 30 so that the cleaning liquid discharged by the pump 13 is supplied to the cleaning unit 30 through the channel 21. The channel 21 is provided inside the tube 20. An example of the material constituting the tube 20 is a resin material having high flexibility. An example of the resin material is EVA (Ethylene Vinyl Acetate copolymer) resin.

[0025] The cleaning unit 30 is, for example, detachable from the main body unit 10. The cleaning unit 30 includes a case 31 and a nozzle 40. An example of the material constituting the case 31 is ABS (Acrylonitrile Butadiene Styrene) resin. The cleaning liquid flowing through the channel 21 of the tube 20 passes through a channel (not shown) inside the case 31 and is supplied to the nozzle 40. The case 31 includes a grip portion 32. The grip portion 32 is configured so that the user can grip it with one hand. The function of the nozzle 40 is to inject the cleaning liquid supplied from the pump 13. The nozzle 40 is, for example, detachably provided on the case 31.

[0026] The cleaning unit 30 further includes an operation unit 33. The operation unit 33 is provided on the grip portion 32. The function of the operation unit 33 is to open and close a water stop valve (not shown) provided in the flow path of the case 31. When the water stop valve is opened by operating the operation unit 33, the cleaning liquid flowing through the tube 20 is jetted from the outlet 41A of the nozzle 40. When the water stop valve is closed by operating the operation unit 33, the cleaning liquid is not jetted from the outlet 41A of the nozzle 40.

[0027] The nozzle 40 includes a first portion 41 and a second portion 42. The first portion 41 is provided on the outlet 41A side with respect to the second portion 42. The first portion 41 is curved with respect to the second portion 42, for example. In one example, the angle formed by the center line CL (see FIG. 2) of the nozzle 40 in the first portion 41 and the center line CL of the nozzle 40 in the second portion 42 is 55°. An example of the material constituting the nozzle 40 is a resin material. An example of the resin material is ASA (Acrylonitrile Styrene Acrylate) resin, ABS resin, or PC (Poly Carbonate) resin.

[0028] FIG. 2 shows a cross section of the nozzle 40 along the center line CL of the flow path FP. The nozzle 40 further includes a flow path forming portion 50. The flow path FP of the nozzle 40 is provided in the flow path forming portion 50. An example of the cross-sectional shape of the flow path FP in a cross section orthogonal to the center line CL of the flow path FP is circular. The cross-sectional shape of the flow path FP is set based on, for example, the ease of flow of the cleaning liquid flowing through the flow path FP. The circular shape includes a substantially circular shape that provides substantially the same effect with respect to the ease of flow of the cleaning liquid flowing through the flow path FP. The substantially circular shape includes an ellipse and a circular shape having slightly minute irregularities.

[0029] The flow path FP includes an inlet 42A and an outlet 41A. The inlet 42A is provided in the second portion 42, for example, and the cleaning liquid is supplied from the pump 13 (see FIG. 1). The inlet 42A is disposed in the case 31 in a state where the nozzle 40 is attached to the case 31 and is connected to the flow path in the case 31. An example of the inner diameter D1 of the inlet 42A is 3.4 mm. The outlet 41A is provided in the first portion 41, for example, and jets the cleaning liquid that has flowed in from the inlet 42A.

[0030] An example of a preferable range regarding the length of the nozzle 40 along the flow path FP of the nozzle 40 is 90 to 120 mm. The length of the nozzle 40 is the length of the flow path FP in the range from the inlet 42A to the outlet 41A. In one example, the length of the nozzle 40 is 105 mm. An example of the length of the first portion 41 along the flow path FP of the nozzle 40 is 22 mm. An example of the tolerance of the length of the first portion 41 is ±1 mm. The inner surface roughness of the flow path FP of the nozzle 40 is preferably 0.2 μm or more.

[0031] The pump 13 supplies the cleaning liquid to the inlet 42A so that the flow rate of the cleaning liquid ejected from the outlet 41A is included in the range of 200 to 350 mL / min. An example of a preferable range regarding the discharge pressure of the pump 13 is 3.0 to 8.0 kgf / cm2. The water pressure of the cleaning liquid ejected from the outlet 41A of the nozzle 40 changes according to the water pressure of the cleaning liquid discharged from the pump 13.

[0032] It is preferable that the maximum discharge pressure of the pump 13 is greater than a predetermined maximum discharge pressure. The predetermined maximum discharge pressure is preferably determined, for example, from the relationship with the force for removing the dirt in the oral cavity by the cleaning liquid ejected from the outlet 41A. An example of a preferable range regarding the predetermined maximum discharge pressure is a range of 4 kgf / cm2 or more. An example of a more preferable range regarding the predetermined maximum discharge pressure is a range of 6 kgf / cm2 or more. In one example, the predetermined maximum discharge pressure is 8 kgf / cm2.

[0033] With reference to FIG. 3, the configuration of the flow path component 50 will be described. The flow path component 50 includes a first component 51, a second component 52, and a narrowing section 53. The first component 51 includes a first flow path FP1. The narrowing section 53 is provided on the downstream side of the first component 51. The narrowing section 53 is configured to narrow the flow path FP. The second component 52 includes a second flow path FP2. The second flow path FP2 is provided on the downstream side of the narrowing section 53 and widens from the side of the narrowing section 53 toward the side of the outlet 41A. The narrowing section 53 includes a third flow path FP3. The third flow path FP3 connects the first flow path FP1 and the second flow path FP2 and narrows from the side of the first flow path FP1 toward the side of the second flow path FP2. The first flow path FP1, the third flow path FP3, and the second flow path FP2 constitute the flow path FP. The flow path component 50 is configured such that cavitation occurs in the cleaning liquid flowing through the flow path FP when the flow rate of the cleaning liquid ejected from the outlet 41A of the nozzle 40 is in the range of 200 to 350 mL / min.

[0034] The narrowing section 53 includes a first wall surface 53A and a second wall surface 53B. The first wall surface 53A and the second wall surface 53B face each other with the center line CL of the flow path FP interposed therebetween in the cross section of the nozzle 40 along the center line CL. A first tangent line T1, which is a tangent line of the first wall surface 53A representing the degree of inclination of the first wall surface 53A with respect to the center line CL in the cross section of the nozzle 40, and a second tangent line T2, which is a tangent line of the second wall surface 53B representing the degree of inclination of the second wall surface 53B with respect to the center line CL in the cross section of the nozzle 40, form an angle (hereinafter referred to as "narrowing section angle A1") that is included in a predetermined first angle range. The predetermined first angle range is an angle range set such that cavitation bubbles are included in the cleaning liquid when the flow rate of the cleaning liquid ejected from the outlet 41A of the nozzle 40 is in the range of 200 to 350 mL / min. In a preferred example regarding the predetermined first angle range, the upper limit value is 135° and the lower limit value is 120°. When the narrowing section angle A1 is 135° or less, the cleaning liquid contains a sufficient amount of cavitation bubbles to sufficiently remove dirt. When the narrowing section angle A1 is 120° or more, the moldability improves when the nozzle 40 is molded using a mold. In one example, the narrowing section angle A1 is 123°. An example of the tolerance of the narrowing section angle A1 is ±2°.

[0035] As shown in FIG. 4, the first wall surface 53A and the second wall surface 53B are curved. The first tangent line T1 is, for example, on the first wall surface 53A, and is a straight line connecting the portion on the most outlet 41A (see FIG. 3) side in the reduced portion 53 and the portion before starting to curve. The second tangent line T2 is, for example, on the second wall surface 53B, and is a straight line connecting the portion on the most outlet 41A side in the reduced portion 53 and the portion before starting to curve.

[0036] The cross-sectional shape of the third flow path FP3 in a cross-section orthogonal to the center line CL of the flow path FP is circular. The reduced portion 53 includes a small-diameter portion 54. The small-diameter portion 54 is the portion on the most outlet 41A side in the reduced portion 53 and is the portion with the smallest inner diameter in the reduced portion 53. The inner diameter of the third flow path FP3 of the small-diameter portion 54 (hereinafter referred to as "small-diameter portion inner diameter D2") is included in a predetermined inner diameter range. The predetermined inner diameter range is an inner diameter range set so that the cleaning liquid ejected from the outlet 41A of the nozzle 40 contains cavitation bubbles when the flow rate of the cleaning liquid is in the range of 200 to 350 mL / min. In a preferred example regarding the predetermined inner diameter range, the upper limit value is 0.85 mm and the lower limit value is 0.80 mm. When the small-diameter portion inner diameter D2 is 0.85 mm or less, the cleaning liquid contains a sufficient amount of cavitation bubbles to remove dirt. When the small-diameter portion inner diameter D2 is 0.80 mm or more, an appropriate flow rate of the cleaning liquid is ejected from the outlet 41A of the nozzle 40. In one example, the small-diameter portion inner diameter D2 is 0.82 mm. An example of the tolerance of the small-diameter portion inner diameter D2 is ±0.02 mm.

[0037] As shown in FIG. 3, the second component 52 includes a third wall surface 52A and a fourth wall surface 52B. The third wall surface 52A and the fourth wall surface 52B face each other across the center line CL in the cross-section of the nozzle 40 along the center line CL of the flow path FP. A third tangent line T3, which is a tangent line of the third wall surface 52A representing the degree of inclination of the third wall surface 52A with respect to the center line CL in the cross-section of the nozzle 40, and a fourth tangent line T4, which is a tangent line of the fourth wall surface 52B representing the degree of inclination of the fourth wall surface 52B with respect to the center line CL in the cross-section of the nozzle 40, form an angle (hereinafter referred to as "second component angle A2") that is included in a predetermined second angle range. The predetermined second angle range is an angle range set such that when the flow rate of the cleaning liquid ejected from the outlet 41A of the nozzle 40 is in the range of 200 to 350 mL / min, the cleaning liquid contains cavitation bubbles. In a preferred example regarding the predetermined second angle range, the upper limit value is 6.5°, and the lower limit value is 5.5°. When the second component angle A2 is 6.5° or less, the cleaning liquid contains a sufficient amount of cavitation bubbles to sufficiently remove dirt. When the second component angle A2 is 5.5° or more, the pressure required for the generation of cavitation easily acts on the cleaning liquid flowing through the second flow path FP2. In one example, the second component angle A2 is 6.0°. An example of the tolerance of the second component angle A2 is ±0.5°.

[0038] The second component 52 is formed, for example, in the range from the reduced portion 53 to the outlet 41A. The length of the second component 52 in the direction along the center line CL of the flow path FP (hereinafter referred to as "second component length L") is included in a predetermined length range. The predetermined length range is a length range set such that when the flow rate of the cleaning liquid ejected from the outlet 41A of the nozzle 40 is in the range of 200 to 350 mL / min, the cleaning liquid contains cavitation bubbles. In a preferred example regarding the predetermined length range, the upper limit value is 10.0 mm, and the lower limit value is 8.5 mm. When the second component length L is 10 mm or less, the comfort given to the user is likely to increase. When the second component length L is 8.5 mm or more, the cleaning liquid contains a sufficient amount of cavitation bubbles to sufficiently remove dirt. In one example, the second component length L is 9.0 mm. An example of the tolerance of the second component length L is 0.1 mm.

[0039] As shown in FIG. 2, the first component 51 includes a fifth wall surface 51A and a sixth wall surface 51B. The fifth wall surface 51A and the sixth wall surface 51B face each other with the center line CL of the flow path FP interposed therebetween in the cross section of the nozzle 40 along the center line CL. A fifth tangent line T5 which is a tangent line of the fifth wall surface 51A representing the degree of inclination of the fifth wall surface 51A with respect to the center line CL in the cross section of the nozzle 40, and a sixth tangent line T6 which is a tangent line of the sixth wall surface 51B representing the degree of inclination of the sixth wall surface 51B with respect to the center line CL in the cross section of the nozzle 40, the angle formed therebetween (hereinafter referred to as "first component angle A3") is preferably included in the range of 1.0 to 2.0°.

[0040] With reference to FIG. 5, an example of a method for manufacturing the nozzle 40 will be described. The nozzle 40 is manufactured using, for example, injection molding. In one example, the nozzle 40 is manufactured using a first component 61 and a second component 62. The first component 61 has a shape along, for example, the wall surfaces 51A, 51B of the first component 51 and the wall surfaces 53A, 53B of the reduced portion 53. The first component 61 includes a recess 61A. The second component 62 has a shape along, for example, the wall surfaces 52A, 52B of the second component 52. The second component 62 includes an insertion portion 62A. The insertion portion 62A can be inserted into the recess 61A.

[0041] The first component 61 and the second component 62 are inserted into a mold (not shown) that forms the outer contour of the nozzle 40 such that the insertion portion 62A of the second component 62 is inserted into the recess 61A of the first component 61. Next, the heated resin is filled into the mold, and the filled resin is solidified. Then, the first component 61 and the second component 62 are pulled out of the mold, and the manufactured nozzle 40 is taken out of the mold. Through the above steps, the nozzle 40 is manufactured. Since the reduced portion angle A1 is included in a predetermined first angle range, the moldability of the nozzle 40 is improved. Further, since the first component angle A3 is included in the range of 1.0 to 2.0°, the operation of pulling out the first component 61 from the mold is easily performed.

[0042] With reference to FIGS. 1 to 3, an example of a method for using the oral cavity cleaning device 1 will be described. The oral cleaning device 1 is used by a user as follows, for example. In the first step, a predetermined amount of cleaning liquid is poured into the tank 16, and the tank 16 is attached to the device main body 11. In the second step, the power of the oral cleaning device 1 is set to on by operating the operation unit of the main body unit 10. When the power of the oral cleaning device 1 is set to on, the pump 13 starts to drive. In the third step, the grip portion 32 of the cleaning unit 30 is gripped, and the outlet 41A of the nozzle 40 is directed into the oral cavity. In the fourth step, the cleaning liquid is jetted from the outlet 41A by operating the operation unit 33 of the cleaning unit 30. For this reason, the oral cavity is cleaned by the cleaning liquid jetted from the outlet 41A.

[0043] In the process in which the cleaning liquid is jetted from the outlet 41A, the cleaning liquid discharged from the pump 13 passes through the flow path FP of the nozzle 40. Since the pressure acting on the cleaning liquid flowing through the third flow path FP3 of the narrowing portion 53 drops below the saturated vapor pressure and the pressure acting on the cleaning liquid flowing through the second flow path FP2 of the second component portion 52 recovers to be equal to or higher than the saturated vapor pressure, cavitation occurs in the cleaning liquid flowing through the flow path FP of the nozzle 40. For this reason, stubborn dirt such as dental plaque is easily removed by the impact accompanying the rupture of the cavitation bubbles contained in the cleaning liquid jetted into the oral cavity from the outlet 41A of the nozzle 40.

[0044] Also, when the flow rate of the cleaning liquid jetted from the outlet 41A of the nozzle 40 is within the range of 200 to 350 mL / min, it has been confirmed that the cleaning liquid jetted into the oral cavity appropriately removes food residues and gives the user a comfortable feeling. Thus, the oral cleaning device 1 has the performance of appropriately removing food residues, the performance of giving the user comfort, and the performance of removing stubborn dirt. Thereby, the added value of the oral cleaning device 1 is increased.

[0045] (Example) The inventors of the present application conducted the first to fourth tests to confirm the influence of the configuration of the flow path component 50 of the oral cleaning device 1. In the first and second tests, the oral cleaning device 1 according to the embodiment (hereinafter referred to as "the oral cleaning device 1 of the embodiment") and the oral cleaning device of the comparative example were used to measure the generation status of cavitation bubbles. In the third and fourth tests, in addition to the oral cleaning device 1 of the embodiment and the oral cleaning device of the comparative example, samples to be cleaned by the oral cleaning device were used to measure the cleaning performance of each oral cleaning device.

[0046] Details of the first test will be described. The specifications of the oral cleaning device 1 of the embodiment used in the first test are as follows. The material constituting the tube 20 is EVA resin. The length of the tube 20 is 1 m. The flow rate of the cleaning liquid sprayed from the outlet 41A of the nozzle 40 is included in the range of 200 to 350 mL / min. The material constituting the nozzle 40 is ASA resin. The reduced portion angle A1 varies for each sample within the range of 120 to 135°. The first component angle A3 is 1°. The second component angle A2 is 6.0°. The inner diameter D2 of the small diameter portion is 0.82 mm. The length L of the second component is 9.0 mm. The inner diameter D1 of the inlet 42A is 3.4 mm. The inner diameter of the outlet 41A is 1.76 mm. The cleaning liquid is tap water. The specifications of the oral cleaning device of the comparative example are substantially the same as those of the oral cleaning device 1 of the embodiment except for the reduced portion angle A1. The reduced portion angle A1 of the oral cleaning device of the comparative example varies for each sample within the range of 140 to 145°.

[0047] In the first test, it was measured whether the cleaning liquid ejected from the nozzle 40 of each sample contained cavitation bubbles. The measurement method was visual inspection using a high-speed video camera. Fig. 6 shows the results of the first test. When the reduced portion angle A1 was 140° or more, it was confirmed that the cleaning liquid ejected from the nozzle 40 substantially did not contain cavitation bubbles. The "×" symbol in Fig. 6 indicates that such a result was confirmed. The state where the cleaning liquid substantially does not contain cavitation bubbles includes the state where the cleaning liquid does not contain cavitation bubbles at all and the state where a very small amount of cavitation bubbles are contained in the cleaning liquid but the amount does not contribute to the removal of dirt. When the reduced portion angle A1 was 135° or less, it was confirmed that the cleaning liquid ejected from the nozzle 40 contained cavitation bubbles. When the reduced portion angle A1 was 120° or more, it was confirmed that the cleaning liquid ejected from the nozzle 40 contained cavitation bubbles. The "○" symbol in Fig. 6 indicates that such a result was confirmed. According to the first test, when the reduced portion angle A1 was within the range of 120° to 135°, it was confirmed that the cleaning ability of the oral cleaning device 1 became higher.

[0048] The details of the second test will be described. The specifications of the oral cleaning device 1 of the example used in the second test are as follows. Except for the reduced portion angle A1 and the second component angle A2, it is the same as the oral cleaning device 1 of the example used in the first test. The reduced portion angle A1 is 123°. The second component angle A2 varies for each sample within the range of 5.5° to 6.5°. The specifications of the oral cleaning device of the comparative example are substantially the same as those of the oral cleaning device 1 of the example except for the second component angle A2. The second component angle A2 of the oral cleaning device of the comparative example varies for each sample within the range of 7.0° to 7.5°.

[0049] In the second test, it was measured whether the cleaning liquid ejected from the nozzle 40 of each sample contained cavitation bubbles. The measurement method was visual inspection using a high-speed video camera. FIG. 7 shows the results of the second test. When the second component angle A2 was 7.0° or more, it was confirmed that the cleaning liquid ejected from the nozzle 40 substantially did not contain cavitation bubbles. The symbol "×" in FIG. 7 indicates that such a result was confirmed. When the second component angle A2 was 6.5° or less, it was confirmed that the cleaning liquid ejected from the nozzle 40 contained cavitation bubbles. When the second component angle A2 was 5.5° or more, it was confirmed that the cleaning liquid ejected from the nozzle 40 contained cavitation bubbles. The symbol "○" in FIG. 7 indicates that such a result was confirmed. According to the second test, when the second component angle A2 was in the range of 5.5 to 6.6°, it was confirmed that the cleaning ability of the oral cleaning device 1 became higher.

[0050] Details of the third test will be described. The specifications of the oral cleaning device 1 of the example used in the third test are as follows. Except for the reduced portion angle A1 and the inner diameter D2 of the small diameter portion, it is the same as the oral cleaning device 1 of the example used in the first test. The reduced portion angle A1 is 123°. The inner diameter D2 of the small diameter portion varies for each sample within the range of 0.80 to 0.85 mm. The oral cleaning device 1 ejects the cleaning liquid from the outlet 41A of the nozzle 40 so that the discharge load of the cleaning liquid is within the range of 18 gf or more. The discharge load is the water pressure of the cleaning liquid ejected from the outlet 41A. The specifications of the oral cleaning device of the comparative example are substantially the same as those of the oral cleaning device 1 of the example except for the inner diameter D2 of the small diameter portion. The inner diameter D2 of the small diameter portion of the oral cleaning device of the comparative example varies for each sample within the range of 0.86 to 0.88 mm.

[0051] The sample to be cleaned used in the third test is a glass plate coated with object X. Object X is applied to the entire one surface of the glass plate such that a layer of object X is formed. Object X has properties similar to those of dental plaque adhering to teeth. An example of object X is artificial dental plaque. In the third test, with the distance between the outlet 41A of nozzle 40 and the sample set at 2.0 mm, the cleaning liquid was sprayed from nozzle 40 for a certain period of time, and after the spraying of the cleaning liquid ended, the amount of object X remaining on the glass plate was measured. From the measurement results, the ratio (hereinafter referred to as "removal rate") of the area S2 of object X remaining on area S1 after the spraying of the cleaning liquid to the area S1 of the area on the glass plate where the cleaning liquid was sprayed was calculated to evaluate the cleaning performance of the oral cleaning device 1. FIG. 8 shows the results of the third test.

[0052] When the inner diameter D2 of the small diameter portion is 0.86 mm or more, it was confirmed that the removal rate was low. This indicates that the cleaning liquid sprayed from nozzle 40 does not contain a sufficient amount of cavitation bubbles to sufficiently remove dirt. When the inner diameter D2 of the small diameter portion is 0.85 or less, it was confirmed that the removal rate was high. This indicates that the cleaning liquid sprayed from nozzle 40 contains a sufficient amount of cavitation bubbles to sufficiently remove dirt. When the inner diameter D2 of the small diameter portion is 0.80 mm or more, it was confirmed that the removal rate was high. According to the third test, when the inner diameter D2 of the small diameter portion is within the range of 0.80 to 0.85 mm, it was confirmed that the cleaning ability of the oral cleaning device 1 becomes higher.

[0053] The details of the fourth test will be described. The specifications of the oral cleaning device 1 of the example used in the fourth test are as follows. Except for the reduced portion angle A1 and the second component length L, it is the same as the oral cleaning device 1 of the example used in the first test. The reduced portion angle A1 is 123°. The second component length L varies for each sample within the range of 8.5 to 10.0 mm. The specifications of the oral cleaning device of the comparative example are substantially the same as those of the oral cleaning device 1 of the example, except for the second component length L. The second component length L of the oral cleaning device of the comparative example is 8.0 mm. The evaluation method of the fourth test is the same as the evaluation method of the third test. FIG. 9 shows the results of the fourth test.

[0054] When the length L of the second component is 8.0 mm, it was confirmed that the removal rate was low. This indicates that the cleaning liquid sprayed from the nozzle 40 does not contain a sufficient amount of cavitation bubbles to sufficiently remove the dirt. When the length L of the second component is 10.0 mm or less, it was confirmed that the removal rate was high. This indicates that the cleaning liquid sprayed from the nozzle 40 contains a sufficient amount of cavitation bubbles to sufficiently remove the dirt. When the length L of the second component is 8.5 mm or more, it was confirmed that the removal rate was high. According to the fourth test, when the length L of the second component is included in the range of 8.5 to 10.0 mm, it was confirmed that the cleaning ability of the oral cavity cleaning device 1 becomes higher.

[0055] (Modification example) The description of the embodiment is an exemplification of the forms that the oral cavity cleaning device and its nozzle according to the present invention can take, and is not intended to limit the form. The present invention can take forms other than the embodiment, for example, modification examples of the embodiment shown below, and forms in which at least two modification examples that do not conflict with each other are combined.

[0056] · The manufacturing method of the nozzle 40 can be arbitrarily changed. In one example, the nozzle 40 is manufactured using insert molding. In the first example shown in FIG. 10, first, the main part 70 that constitutes the wall surfaces 53A, 53B of the reduced part 53 and the surrounding wall surfaces 51A, 51B, 52A, 52B is manufactured. In one example, the main part 70 is manufactured using the first component 61, the second component 62 (see FIG. 5), and a mold (not shown) that constitutes the outer shell of the main part 70. Next, the first component 61 and the second component 62 are inserted into a mold (not shown) that constitutes the outer shell of the nozzle 40 so as to support the main part 70. Then, by filling the heated resin into the mold, the nozzle 40 including the main part 70 is manufactured.

[0057] In the second example shown in FIG. 11, the mold forming the outer contour of the nozzle 40 is different from that in the first example. When the nozzle 40 is manufactured using insert molding, it is necessary to cover the main part 70 with heated resin. For this reason, in the first example, a mold is used such that the entire outer diameter of the nozzle 40 becomes large. On the other hand, in the second example, the nozzle 40 is manufactured using a mold such that only the portion corresponding to the main part 70 in the outer diameter of the nozzle 40 becomes large. For this reason, the nozzle 40 is miniaturized.

[0058] · The magnitude of the reduced portion angle A1 can be arbitrarily changed. In the first example, the reduced portion angle A1 is less than 120°. In the second example, the reduced portion angle A1 is greater than 135°. · The magnitude of the second component angle A2 can be arbitrarily changed. In the first example, the second component angle A2 is less than 5.5°. In the second example, the second component angle A2 is greater than 6.5°.

[0059] · The magnitude of the inner diameter D2 of the small diameter portion can be arbitrarily changed. In one example, the inner diameter D2 of the small diameter portion is greater than 0.85 mm. · The length L of the second component can be arbitrarily changed. In the first example, the length L of the second component is less than 8.5 mm. In the second example, the length L of the second component is greater than 10.0 mm. · The shape of the nozzle 40 can be arbitrarily changed. In one example, the first part 41 of the nozzle 40 is not curved with respect to the second part 42.

[0060] (An example of a form that an oral cleaning device and its nozzle can take) (Form 1) A nozzle including a flow path component provided with a flow inlet through which a cleaning liquid is supplied and a flow path including a flow outlet through which the cleaning liquid is ejected, A pump that supplies the cleaning liquid to the flow inlet so that the flow rate of the cleaning liquid ejected from the flow outlet is included in the range of 200 to 350 mL / min, The flow path component includes a first component including a first flow path that constitutes the flow path, a reduction part provided on the downstream side of the first component and narrowing the flow path, and a second component provided on the downstream side of the reduction part and including a second flow path that widens from the reduction part side toward the flow outlet side. The first component, the reduction part, and the second component are configured such that cavitation occurs in the cleaning liquid flowing through the flow path when the flow rate of the cleaning liquid ejected from the flow outlet is included in the range of 200 to 350 mL / min, The reduction part includes a curved wall surface, The length of the nozzle in the direction along the center line of the nozzle is referred to as the nozzle length, The nozzle length is included in the range of 90 to 120 mm An oral cleaning device. (Form 2) The first component includes a fifth wall surface and a sixth wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle, The second component includes a third wall surface and a fourth wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle, The angle formed by the tangent line of the fifth wall surface and the tangent line of the sixth wall surface in a cross section along the center line of the nozzle is referred to as the first component angle, The angle formed by the tangent line of the third wall surface and the tangent line of the fourth wall surface in a cross section along the center line of the nozzle is referred to as the second component angle, The first component angle is smaller than the second component angle The oral cleaning device according to Form 1. (Form 3) The first component includes a fifth wall surface and a sixth wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle, The reduction part includes a first wall surface and a second wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle, In a cross-section along the center line of the nozzle, the angle formed by the tangent line of the fifth wall surface and the tangent line of the sixth wall surface is referred to as the first component angle. In a cross-section along the center line of the nozzle, the angle formed by the tangent line of the first wall surface and the tangent line of the second wall surface is referred to as the narrowing portion angle. The first component angle is smaller than the narrowing portion angle. The oral cavity cleaning device according to any one of Forms 1 or 2. (Form 4) The narrowing portion includes a first wall surface and a second wall surface that face each other across the center line of the nozzle in a cross-section along the center line of the nozzle. In a cross-section along the center line of the nozzle, the angle formed by the tangent line of the first wall surface and the tangent line of the second wall surface is referred to as the narrowing portion angle. The narrowing portion angle is included in the range of 120° to 135°. The oral cavity cleaning device according to any one of Forms 1 to 3. (Form 5) The nozzle includes a first portion including the outlet and a second portion including the inlet. The angle formed by the center line of the nozzle in the first portion and the center line of the nozzle in the second portion is referred to as the nozzle bending angle. The nozzle bending angle is included in the range of 0° to 55°. The oral cavity cleaning device according to any one of Forms 1 to 4. (Form 6) The nozzle includes a first portion including the outlet and a second portion including the inlet. The length of the first portion in the direction along the center line of the nozzle is referred to as the first portion length. The length of the second component in the direction along the center line of the nozzle is referred to as the second component length. The difference between the first portion length and the second component length is referred to as the upstream length of the first portion. The upstream length of the first portion is longer than the second component length. The oral cavity cleaning device according to any one of Forms 1 to 5. (Form 7) The nozzle includes a first portion including the outlet and a second portion including the inlet. The length of the first portion in the direction along the center line of the nozzle is referred to as the first portion length. The length of the second portion in the direction along the center line of the nozzle is referred to as the second portion length. The second portion length is longer than the first portion length. The oral cavity cleaning device according to any one of Forms 1 to 6. (Form 8) The nozzle includes a second portion including the inlet. The length of the second portion in the direction along the center line of the nozzle is referred to as the second portion length. The second portion length is included in the range of 68 mm to 98 mm. The oral cavity cleaning device according to any one of Forms 1 to 7. (Form 9) The length of the second component in the direction along the center line of the nozzle is referred to as the second component length. The length of the second component part is included in the range of less than 8.5 mm. The oral cavity cleaning device according to any one of Forms 1 to 8. (Form 10) The nozzle includes a first part including the outlet and a second part including the inlet. The narrowing part includes a first wall surface and a second wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle. The angle formed by the center line of the nozzle in the first part and the center line of the nozzle in the second part is called the nozzle bending angle. The angle formed by the tangent line of the first wall surface and the tangent line of the second wall surface in a cross section along the center line of the nozzle is called the narrowing part angle. The ratio of the nozzle bending angle to the narrowing part angle is included in the range of 0 to 0.46. The oral cavity cleaning device according to any one of Forms 1 to 9. (Form 11) The first component part includes a fifth wall surface and a sixth wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle. The second component part includes a third wall surface and a fourth wall surface that face each other across the center line of the nozzle in a cross section along the center line of the nozzle. The angle formed by the tangent line of the fifth wall surface and the tangent line of the sixth wall surface in a cross section along the center line of the nozzle is called the first component part angle. The angle formed by the tangent line of the third wall surface and the tangent line of the fourth wall surface in a cross section along the center line of the nozzle is called the second component part angle. The ratio of the first component part angle to the second component part angle is included in the range of 0.15 to 0.36. The oral cavity cleaning device according to any one of Forms 1 to 10. (Form 12) The inner diameter of the inlet is called the inlet inner diameter. The ratio of the inlet inner diameter to the nozzle length is included in the range of 2.83 to 3.78. The oral cavity cleaning device according to any one of Forms 1 to 11. (Form 13) A method for manufacturing a nozzle for manufacturing a nozzle of an oral cavity cleaning device, The nozzle is a flow path component provided with a flow path including an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is ejected, a first part including the outlet, and a second part including the inlet, The flow path component is a narrowing part that narrows the flow path, a first component part provided upstream of the narrowing part, and a second component part provided downstream of the narrowing part, The manufacturing method uses a first part and a second part for manufacturing the nozzle. The first part has a shape along the wall surface of the first component part and the wall surface of the narrowing part. The second part has a shape along the wall surface of the second component part. The first component includes a concave portion, the second component includes an insertion portion that can be inserted into the concave portion, the manufacturing method includes a step 1A in which the insertion portion is inserted into the concave portion, and the first component and the second component are inserted into a mold that constitutes the outer contour of the nozzle, a step 1B in which, after the implementation of step 1A, heated resin is filled into the mold, the filled resin is solidified, and the nozzle is formed, and a step 1C in which, after the implementation of step 1B, the nozzle is taken out of the mold. A method for manufacturing a nozzle of an oral cavity cleaning device. (Form 14) A method for manufacturing a nozzle for manufacturing a nozzle of an oral cavity cleaning device, wherein the nozzle includes a flow path component provided with a flow path including an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is ejected, a first portion including the outlet, and a second portion including the inlet, wherein the flow path component includes a reducing portion that narrows the flow path, a first component portion provided upstream of the reducing portion, a second component portion provided downstream of the reducing portion, a main portion that constitutes the wall surface of the reducing portion, the wall surface of the first component portion, and the wall surface of the second component portion, and a peripheral portion provided around the main portion and constituting the outer contour of the nozzle, wherein the manufacturing method uses a first component and a second component for manufacturing the nozzle, the first component has a shape along the wall surface of the first component portion and the wall surface of the reducing portion, the second component has a shape along the wall surface of the second component portion, the first component includes a concave portion, the second component includes an insertion portion that can be inserted into the concave portion, the manufacturing method includes a step 2A in which the insertion portion is inserted into the concave portion, and the first component and the second component are inserted into a mold for the main portion that constitutes the outer contour of the main portion, a step 2B in which, after the implementation of step 2A, heated resin is filled into the mold for the main portion, the filled resin is solidified, and the main portion is formed, a step 2C in which, after the implementation of step 2B, the main portion, the first component, and the second component are taken out of the mold for the main portion, a step 2D in which, after the implementation of step 2C, the main portion supported by the first component and the second component is inserted into a mold for the peripheral portion that constitutes the outer contour of the nozzle, a step 2E in which, after the implementation of step 2D, heated resin is filled into the mold for the peripheral portion, the filled resin is solidified, the peripheral portion is formed, and the nozzle is formed. After the implementation of the said step 2E, it includes a step 2F of taking out the said nozzle from the mold for the peripheral part A method for manufacturing a nozzle of an oral cavity cleaning device

Industrial Applicability

[0061] The oral cavity cleaning device and its nozzle according to the present invention can be used in various oral cavity cleaning devices including household and business use.

Explanation of Signs

[0062] 1: Oral cavity cleaning device 13: Pump 40: Nozzle 41A: Outlet 42A: Inlet 50: Flow path component 51: First component 52: Second component 52A: Third wall surface 52B: Fourth wall surface 53: Reducing section 53A: First wall surface 53B: Second wall surface 54: Small-diameter section CL: Center line FP: Flow path FP1: First flow path FP2: Second flow path FP3: Third flow path (flow path) T1: First tangent line T2: Second tangent line T3: Third tangent line T4: Fourth tangent line

Claims

1. A nozzle of an oral cleaning device, wherein the nozzle includes a flow path component provided with a flow path including an inlet through which a cleaning liquid is supplied and an outlet through which the cleaning liquid is ejected, the flow path component includes a first component including a first flow path that constitutes the flow path, a reducing part provided on the downstream side of the first component and narrowing the flow path, a second component provided on the downstream side of the reducing part and including a second flow path that widens from the reducing part side toward the outlet side, and includes the second component includes a third wall surface and a fourth wall surface that face each other across the center line of the nozzle in a cross section including the center line of the nozzle, the first component includes a fifth wall surface and a sixth wall surface that face each other across the center line of the nozzle in a cross section including the center line of the nozzle, in a cross section including the center line of the nozzle, the distance between the third wall surface and the fourth wall surface that defines the second flow path is referred to as the inner dimension of the second flow path, the portion connecting to the reducing part, which is the most downstream part in the first flow path, is referred to as a connecting part, in a cross section including the center line of the nozzle, the distance between the fifth wall surface and the sixth wall surface that defines the connecting part is referred to as the inner dimension of the connecting part, the second component includes an upstream part of the second component provided on the downstream side of the reducing part and a downstream part of the second component provided on the downstream side of the upstream part of the second component, the upstream part of the second component includes an upstream part small inner dimension part where the inner dimension of the second flow path is smaller than the inner dimension of the connecting part, the downstream part of the second component includes a downstream part small inner dimension part where the inner dimension of the second flow path is smaller than the inner dimension of the connecting part, the reducing part includes a third flow path, the third flow path connects the first flow path and the second flow path and narrows from the first flow path side toward the second flow path side, the reducing part includes a first wall surface and a second wall surface that face each other across the center line of the nozzle in a cross section including the center line of the nozzle, in a cross section including the center line of the nozzle, the distance between the first wall surface and the second wall surface that defines the third flow path is referred to as the inner dimension of the third flow path, the reducing part includes a small inner dimension part that is the part where the inner dimension of the third flow path is the smallest, the small inner dimension part is the most outlet-side part in the reducing part and is connected to the most inlet-side opening in the second flow path, The third flow path and the second flow path are configured such that the inner dimension of the third flow path decreases as it goes from the first flow path side toward the small inner dimension portion, and the inner dimension of the second flow path increases as it goes from the small inner dimension portion toward the outlet side. In a cross section including the center line of the nozzle, the distance between the connection portion and the small inner dimension portion in the direction along the center line of the nozzle is referred to as the connection portion - small inner dimension portion distance. In a cross section including the center line of the nozzle, the distance between the small inner dimension portion and the most downstream portion in the second flow path in the direction along the center line of the nozzle is referred to as the small inner dimension portion - most downstream portion distance. The connection portion - small inner dimension portion distance is shorter than the small inner dimension portion - most downstream portion distance. Nozzle.

2. The downstream side small inner dimension portion is configured such that the inner dimension of the second flow path expands at a constant rate. The nozzle according to claim 1.

3. The downstream side small inner dimension portion is configured to guide the cleaning liquid by the third wall surface and the fourth wall surface. The nozzle according to claim 1 or 2.

4. The downstream side small inner dimension portion is configured to be surrounded by the third wall surface and the fourth wall surface over the entire circumference around the center line of the nozzle. The nozzle according to any one of claims 1 to 3.

5. A first portion including the outlet, A second portion including the inlet, and includes, The first portion includes a part of the first component, the reduced portion, and the second component. The second portion includes another part of the first component. The length of the first portion in the direction along the center line of the nozzle is referred to as the first portion length. The first portion length is 22 mm or less. The nozzle according to any one of claims 1 to 4.

6. The length of the second portion in the direction along the center line of the nozzle is referred to as the second portion length. The second portion length is 98 mm or less. The nozzle according to claim 5.

7. The length of the second component in the direction along the center line of the nozzle is referred to as the second component length. The second component length is 10 mm or less. The nozzle according to any one of claims 1 to 6.

8. In a cross section including the center line of the nozzle, the distance between the fifth wall surface and the sixth wall surface that define the first flow path is referred to as the first flow path inner dimension. The inner dimension of the second flow path of the downstream side small inner dimension portion is smaller than the first flow path inner dimension. The nozzle according to any one of claims 1 to 7.

9. In a cross-section including the center line of the nozzle, the distance between the third wall surface and the fourth wall surface that defines the outlet is referred to as the inner dimension of the outlet. In a cross-section including the center line of the nozzle, the distance between the fifth wall surface and the sixth wall surface that defines the inlet is referred to as the inner dimension of the inlet. The inner dimension of the outlet is smaller than the inner dimension of the inlet. The nozzle according to any one of claims 1 to 8.

10. In a cross-section including the center line of the nozzle, the distance between the third wall surface and the fourth wall surface that defines the outlet is referred to as the inner dimension of the outlet. The inner dimension of the outlet is 2.0 mm or less. The nozzle according to any one of claims 1 to 9.

11. A first part including the outlet, A second part including the inlet, and The first part includes a part of the first component, the reduced part, and the second component. The second part includes another part of the first component. The length of the first part in the direction along the center line of the nozzle is referred to as the length of the first part. The length of the second component in the direction along the center line of the nozzle is referred to as the length of the second component. The difference between the length of the first part and the length of the second component is longer than the length of the second component. The nozzle according to any one of claims 1 to 10.

12. In a cross-section including the center line of the nozzle, the distance between the fifth wall surface and the sixth wall surface that defines the inlet is referred to as the inner dimension of the inlet. The length of the nozzle along the flow path is referred to as the nozzle length. The ratio of the nozzle length to the inner dimension of the inlet is included in the range of 26 to 35. The nozzle according to any one of claims 1 to 11.

13. A first part including the outlet, A second part including the inlet, and The first part includes a part of the first component, the reduced part, and the second component. The second part includes another part of the first component. The angle formed by the center line of the nozzle in the first part and the center line of the nozzle in the second part is referred to as the nozzle bending angle. The nozzle bending angle is 55° or less. The nozzle according to any one of claims 1 to 12.

14. In a cross-section including the center line of the nozzle, the angle formed by the tangent line of the fifth wall surface and the tangent line of the sixth wall surface is referred to as the first component angle. In a cross-section including the center line of the nozzle, the angle formed by the tangent line of the third wall surface and the tangent line of the fourth wall surface is referred to as the second component angle. The first component angle is smaller than the second component angle. The nozzle according to any one of claims 1 to 13.

15. The ratio of the angle of the first component part to the angle of the second component part is included in the range of 0.15 to 0.

36. The nozzle according to claim 14.

16. In a cross-section including the center line of the nozzle, the angle formed by the tangent line of the first wall surface and the tangent line of the second wall surface is called the reduced portion angle. The reduced portion angle is greater than 135°. The nozzle according to any one of claims 1 to 15.

17. In a cross-section including the center line of the nozzle, the angle formed by the tangent line of the fifth wall surface and the tangent line of the sixth wall surface is called the first component part angle. The first component part angle is smaller than the reduced portion angle. The nozzle according to claim 16.

18. The flow path includes an arc in the outer shape that defines the shape of a cross-section orthogonal to the center line of the nozzle. The nozzle according to any one of claims 1 to 17.

19. The shape of the inlet in a cross-section orthogonal to the center line of the nozzle is circular. The nozzle according to any one of claims 1 to 18.

20. The outlet includes an arc in the outer shape that defines the shape of a cross-section orthogonal to the center line of the nozzle. The nozzle according to any one of claims 1 to 19.

21. The shape of the outlet in a cross-section orthogonal to the center line of the nozzle is elliptical. The nozzle according to claim 20.

22. When the flow rate of the cleaning liquid sprayed from the outlet is included in the range of 200 to 350 mL / min, the flow path component part is configured such that cavitation occurs in the cleaning liquid flowing through the flow path. The nozzle according to any one of claims 1 to 21.

23. An oral cleaning device including the nozzle according to any one of claims 1 to 22. Oral cleaning device.

24. Including a pump for supplying the cleaning liquid to the inlet. The oral cleaning device according to claim 23.

25. A main body unit including the pump, A cleaning unit including the nozzle, And a tube connecting the main body unit and the cleaning unit such that the cleaning liquid discharged by the pump is supplied to the cleaning unit. The oral cleaning device according to claim 24.

26. The pump supplies the cleaning liquid to the inlet so that the flow rate of the cleaning liquid sprayed from the outlet is included in the range of 200 to 350 mL / min. The oral cleaning device according to claim 24 or 25.

27. The discharge pressure of the pump is included in the range of 3.0 to 8.0 kgf / cm2, The oral cavity cleaning device according to any one of claims 24 to 26.

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