JP2013149360A - Manufacturing method of float switch and float switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a float switch for shortening manufacturing time and eliminating the need of installing an air discharge port and closure thereof.SOLUTION: A manufacturing method of a float switch is for joining a float body 12 and a float cover 13. An external shape of the float body is such a shape that a column 42 is connected to a bottom surface of a spherical segment body 41, an open end part of a columnar shape is a body joining part 43, an external shape of the float cover is such a shape that a column 62 is connected to a bottom surface of a spherical segment body 61, and an open end part of a columnar shape is a cover joining part 63. The body joining part 43 has a first fusion surface 47 and the cover joining part 63 has a fusion rib 66. The first fusion surface and the fusion rib are vibrated while being pressurized, fused and bonded.

Description

  The present invention relates to a float switch. The float switch is used for a water level sensor that detects a change in liquid level due to increase or decrease of water, oil, sewage, or the like in a storage tank, for example.

  For example, in a sewage treatment facility, an automatic drainage device is installed to keep the amount of sewage in a storage tank constant. This automatic drainage device is configured to detect a change in the water level accompanying an increase or decrease in the amount of sewage, drive a drainage pump in accordance with the detected water level, and thereby control the amount of sewage. In the case of detecting the water level in such a storage tank, conventionally, a float switch in which a switch unit such as a micro switch, a mercury switch, or a magnetic reed switch is accommodated is generally used (see, for example, Patent Document 1). ). This float switch is configured to float on the surface of the sewage, detect the change in the angle of the float switch due to the change in the level of the sewage by the switch unit, and thereby output an on / off signal.

  The float switch is manufactured by bonding a float body and a float cover. 6A and 6B are explanatory views for explaining a conventional manufacturing method of a float switch. FIG. 6A is a sectional view of a float switch component before bonding, and FIG. 6B is a sectional view of the float switch after bonding. The figure is shown. In the float switch, the float body 82 and the float cover 83 are bonded with an adhesive.

  Since the adhesive requires a certain time for solidification, the manufacturing time becomes long. Further, since the adhesive contains an organic solvent, facilities such as exhaust for maintaining a good working environment are required.

  Furthermore, a certain amount of paste 84 and 85 is required for bonding. The float needs to be sealed inside, and the glue margin 84 and the glue margin 85 are rubbed when the float body 82 and the float cover 83 are bonded. For this reason, unless special treatment is performed, the volume of air corresponding to the adhesive margin surface remains in the float in a compressed state. The compressed air prevents good adhesion and prevents the use of a float switch at elevated temperatures.

  Therefore, conventionally, an air discharge port 86 is provided in advance in the float cover 83, and a plug 87 is bonded to the air discharge port 86 after the float body 82 and the float cover 83 are bonded. This plugging process also complicates the manufacturing process of the float switch and lengthens the manufacturing time.

  In FIG. 6, illustration of the switch unit held by the float body is omitted.

Japanese Patent Application Laid-Open No. 08-171840

  The present invention provides a method for manufacturing a float switch that joins a float body and a float cover, shortens the manufacturing time, eliminates the need for maintenance of the work environment, and eliminates the need for installing an air outlet and closing the plug. And

  The present invention also provides a float switch manufactured by such a manufacturing method.

  Means for solving the problems will be described below. For ease of understanding, description will be made with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited to the embodiments.

A method for manufacturing a float switch according to one aspect of the present invention includes:
In the manufacturing method of the float switch in which the switch unit is housed in the hollow float,
The float is a float body (12) holding the switch unit (14) and a float cover (13) joined together,
The switch unit (14) outputs an ON signal when the operation axis (19) is parallel to the vertical line, and outputs an OFF signal when the operation axis is reversed.
The external shape of the float body (12) is a shape in which a cylinder (42) is coupled to the bottom surface of a spherical body (41), and the open end of the columnar shape is a body joint portion (43) in the float body. And
In the float body, the switch unit is held in parallel with the rotational axis in the cylindrical shape, the operation axis (19),
The outer shape of the float cover (13) is a shape in which a cylinder (62) is coupled to the bottom surface of the spherical body (61), and the open end of the columnar shape is the cover joint portion (63) in the float cover. And
Either one of the main body joint portion or the cover joint portion has an outer peripheral wall (46) that rises from the joint portion and has an outer peripheral surface that is an extended surface (45) of the outer peripheral surface (44). It has a first melting surface (47) on the side, and the other has a melting rib (66) whose inner peripheral surface is an extended surface (65) of the inner peripheral surface (64) rising from the joint portion,
A manufacturing method of a float switch that joins the float body and the float cover by oscillating while pressing the first melting surface (47) and the melting rib (66) and melt-bonding the first melting surface and the melting rib. It is.

In the method of manufacturing a float switch according to a preferred embodiment of the present invention,
The inner shape of the float main body has an inner diameter that is larger from the apex of the spherical body shape toward the open end of the cylindrical shape, or the inner diameter is equal,
The outer shape of the float body is such that the outer diameter increases from the apex of the spherical shape to the open end of the cylindrical shape or the outer diameter is equal,
The inner shape of the float cover has an inner diameter that is increased from the apex of the spherical body shape toward the open end of the cylindrical shape, or the inner diameter is equal,
The outer shape of the float cover may be such that the outer diameter increases from the apex of the spherical shape to the open end of the cylindrical shape, or the outer diameter is equal.

  According to this preferred embodiment, the manufacturing process of the float main body and the float cover can be performed with a mold having a simple structure, and the molded product can be easily taken out from the mold after molding. As a result, a float switch can be manufactured at low cost. In particular, the mold can maintain a simple structure, and the thickness of the joint portion of the main body can be made thick enough for melt bonding without increasing the thickness of the spherical notch-shaped portion of the float main body. Similarly, the mold can maintain a simple structure, and the thickness of the cover joint portion can be made sufficient for melt bonding without increasing the thickness of the spherical shape of the float cover. Therefore, it is possible to save the amount of resin necessary for float manufacturing while maintaining the strength of the float after melt bonding.

  In the float switch manufacturing method according to another preferred embodiment of the present invention, the outer peripheral surface of the main body joint portion and the cover joint portion is the same, and the outer surface of the main body joint portion and the cover joint portion is either. One of the thicknesses may be thick, and the outer peripheral wall may be provided in the thick joint portion.

  According to this preferred embodiment, in the vibration (heat generation) process in the vibration melting and bonding step, the melting rib is always in contact with the first melting surface, so that the melting rib is efficiently heated and melted. As a result, the strength of the float melt bonded portion can be further improved, and the sealing performance can be further improved.

  In the method for manufacturing a float switch according to another preferred embodiment of the present invention, the vibration method for vibrating the first molten surface and the molten rib while applying pressure may be orbital vibration.

  According to this preferred embodiment, most of the region where the molten rib in the orbital vibration is slid in contact with the molten rib is welded to the molten rib. Therefore, vibration energy is efficiently used for welding work.

A float switch according to another aspect of the present invention includes:
In the float switch that houses the switch unit in the hollow float,
The float is obtained by joining a float body holding the switch unit and a float cover,
The switch unit outputs an ON signal when the operation axis is parallel to a vertical line, and outputs an OFF signal when the operation axis is reversed.
The outer shape of the float main body is a shape in which a cylinder is coupled to the bottom surface of a sphere, and the open end of the columnar shape in the float main body is a main body joint portion.
In the float body, the switch unit is held in parallel with the rotation center axis in the cylindrical shape,
The outer shape of the float cover is a shape in which a cylinder is coupled to the bottom surface of the spherical body, and the open end of the columnar shape in the float cover is a cover joint portion.
Either one of the main body joint portion and the cover joint portion has an outer peripheral wall that rises from the joint portion and has an extended surface of the outer peripheral surface as its outer peripheral surface.
The main body bonding portion and the cover bonding portion are melt-bonded on the inner peripheral side in contact with the outer peripheral wall.

  In the float switch manufacturing method according to the present invention, the float main body and the float cover are vibration-melt bonded together with other invention specific matters. For this reason, an adhesive surface adheres in a short time. In addition, since the portion involved in melt bonding is small, the amount of air added to the float during bonding is small, so that special air discharge and subsequent plugging are unnecessary.

  Furthermore, the float switch manufacturing method according to the present invention, together with other invention-specific matters, holds the switch unit in the float body, the outer shape of the float body is a combined shape of a spherical notch and a cylinder, The operation axis is held parallel to the center axis of rotation in the cylindrical shape. The float has a shape in which the length is extended by an amount equivalent to the height of the cylinder while maintaining a substantially spherical shape. On the other hand, the switch unit usually has a long dimension in the operation axis direction. According to the present invention, the long dimension direction of the switch unit is accommodated in the internal space obtained by extending the length of the float. Therefore, it is not necessary to make the float a large sphere having a diameter larger than the length of the switch unit. For this reason, the amount of resin required for the float can be saved.

  The columnar portion of the float body and the columnar portion of the float cover accommodate the operation axis direction of the switch unit described above, and at the same time provide a body joint portion and a cover joint portion.

FIG. 1 is an explanatory diagram showing the internal state of the first float switch. FIG. 2 is a partial cross-sectional explanatory view of the float body 12 and the float cover 13 according to the first float switch. FIG. 3 is an enlarged cross-sectional view of a float joint portion according to the first float switch. FIG. 4 is an explanatory diagram showing the internal state of the second float switch. FIG. 5 is a schematic view showing a drainage device of a sewage septic tank using a float switch. FIG. 6 is an explanatory view for explaining a conventional manufacturing method of a float switch.

  Hereinafter, a float switch manufacturing method and a float switch according to an embodiment of the present invention will be further described with reference to the drawings. In the drawings referred to in this specification, in order to facilitate the understanding of the present invention, some of the components are schematically illustrated in an exaggerated manner. For this reason, the dimension, ratio, etc. between components may differ from a real thing. Further, the dimensions, materials, shapes, relative positions, etc. of the members and parts described in the embodiments of the present invention are not intended to limit the scope of the present invention to those unless otherwise specified. It is merely an illustrative example.

  FIG. 1 is an explanatory diagram showing the internal state of the first float switch. The first float switch 11 houses a switch unit 14 in a hollow float. The float is formed by joining the float body 12 and the float cover 13.

  Inside the float body, a unit holder 112 is fixed to the base of the float body. The switch unit 14 is held and fixed in the unit holder 112. In the switch unit 14, there are a micro switch 15 having an operation lever 16 and a weight 17 slidably accommodated in a guide cylinder 18. The operation lever 16 of the micro switch 15 is urged in the opening direction (left side in FIG. 1) by the ridge. In this state, the microswitch 15 outputs an off signal to the electric wire 20.

  When the switch unit 14 is rotated and the operation shaft 19 is directed in the vertical direction, that is, when the tip of the arrow indicating the operation shaft 19 is directed in the direction of gravity (downward), the weight 17 is moved in the guide cylinder 18 and the operation lever is moved. Press 16 down. In this state, the microswitch 15 outputs an ON signal to the electric wire 20.

  The operation axis of the switch unit can be said to be a straight line indicating a direction in which the switch unit outputs an on / off signal when the operation axis faces a specific direction in the three-dimensional space. In general, the dimension of the switch unit is the largest in the direction parallel to the operation axis compared to the dimension in the other direction.

  An intermediate point of the electric wire 20 is fixed to an anchor weight (not shown). The electric wire 20 transmits a signal of the microswitch and plays a role of holding the float switch freely in a certain three-dimensional region.

  When the switch unit 14 rotates next and the weight 17 moves in a direction away from the operation lever 16 (that is, when the operation shaft 19 is reversed), the operation lever 16 returns to the urging state. In this state, the microswitch 15 outputs an off signal to the electric wire 20.

  As described above, in the description of the switch unit and the operation axis, it has been described that the operation axis is directed in the vertical direction to output an ON signal, and is inverted to output an OFF signal. This is a simplification for ease of explanation. Actually, when the crossing angle between the motion axis and the vertical direction (the smaller one of the two crossing angles) falls below a certain value, an ON signal is output, and when the same crossing angle falls below a certain value, it turns off. Output a signal.

  FIG. 2 is a partial cross-sectional explanatory view of the float body 12 and the float cover 13 according to the first float switch. In the figure, the upper half shows the outer shape, and the lower half shows the cross section. FIG. 3 is an enlarged cross-sectional view of a float joint portion according to the first float switch.

  The outer shape of the float body 12 is a shape in which a cylindrical portion 42 is coupled to the bottom surface of the spherical body 41. The open end of the cylindrical portion 42 is a main body joint portion 43. The main body joint portion 43 has a hollow concentric shape. In the float main body 12, the top 48 of the spherical missing body is a through hole of the electric wire 20. The top 48 has a cylindrical shape that is smaller in diameter and height than the cylindrical portion 42.

  In the present invention, a “sphere notch” that describes a shape refers to a space figure obtained by cutting a sphere along one plane. In the spherical body, the cut plane is called a bottom surface, and a point at the maximum vertical distance from the bottom surface is called a vertex. Further, in the float main body and the float cover, in order that “the inner diameter becomes larger or the inner diameter becomes equal from the apex of the spherical shape to the open end of the cylindrical shape”, the spherical shape is a semicircular sphere. Or less than a hemisphere.

  The main body joint portion 43 has an outer peripheral wall 46 that rises from the joint portion and goes around the outer peripheral side of the joint portion. The outer periphery of the outer peripheral wall 46 is an extended surface 45 of the outer peripheral surface 44 of the float body 12. Here, the outer peripheral surface 44 is an outer peripheral surface of the cylindrical portion 42.

  On the inner peripheral side of the outer peripheral wall 46, there is a first melting surface 47 in contact with the wall surface falling from the front end surface of the outer peripheral wall.

  The inner shape of the float body 12 has a concentric cross section, and is directed to the open end (equal to the main body joint portion 43) from the apex 48 of the spherical notch 41, and the inner diameter thereof is increased or adjacent to the portion. The inner diameter is the same. In FIG. 2, an arrow 51 indicates a direction from the apex 48 of the spherical body toward the open end of the cylindrical portion. Arrows 52, 53, and 54 each indicate an inner diameter.

When the lengths of the arrows are respectively represented by L52, L53, and L54, the above relationship can be expressed by Expression (1).
L52 ≦ L53 ≦ L54 Formula (1)

  The float body 12 satisfying the formula (1) can be molded using a mold having a simple structure when it is manufactured by molding, and can be easily taken out from the mold.

  Further, the outer shape of the float main body 12 has a concentric cross section, and faces the open end (equal to the main body joining portion 43) from the apex 48 of the spherical notch 41, and its outer diameter increases or is adjacent. The outer diameter is the same at the site. The float main body 12 that satisfies the relationship of the external shape can be formed by using a mold having a simple structure and can be easily taken out from the mold when it is manufactured by molding. is there.

  Exemplifying the shape of the float main body 12 that satisfies the formula (1), a cylinder having an outer periphery equal to the outer periphery of the bottom surface on the bottom surface of the spherical body, and a cylinder having the same thickness as the thickness appearing on the bottom surface is coupled. Shape.

  When the float body has a shape that satisfies the formula (1) or the like, the thickness of the body joining portion can be increased and sufficient melt adhesive strength can be obtained.

  On the other hand, it is conceivable to increase the wall thickness of the main body joint portion by expanding the diameter of the main body joint portion into a flange shape projecting in the inner circumference side, outer circumference side or both the inner circumference side and the outer circumference side. The float main body 12 having such an inner shape and / or outer shape cannot satisfy the expression 1, and cannot satisfy the relationship of the above-described outer shape. Such a float body molded product cannot be taken out with a simple mold.

  The outer shape of the float cover 13 is a shape in which a cylindrical portion 62 is coupled to the bottom surface of the spherical notch 61. An open end portion of the cylindrical portion 62 is a cover joint portion 63. The cover joint portion 63 has a hollow concentric shape.

  The inner shape of the float cover 13 has a concentric cross section, and is directed to the open end (equal to the cover joining portion 63) from the apex 68 of the ball-off body 61, and the inner diameter thereof increases or is adjacent. The inner diameter is the same. In FIG. 2, an arrow 71 indicates a direction from the apex 68 of the spherical body toward the open end of the cylindrical portion.

Arrows 72, 73, and 74 each indicate an inner diameter. When the lengths of the arrows are expressed by L72, L73, and L74, respectively, the above relationship can be expressed by Expression (2).
L72 ≦ L73 ≦ L74 Formula (2)

  The float cover 13 satisfying the expression (2) can be molded using a mold having a simple structure when manufactured by molding, and can be easily taken out from the mold.

  The outer shape of the float cover 13 has a concentric cross section, and faces the open end portion (equal to the cover joint portion 63) from the apex 68 of the spherical notch 61, and its outer diameter increases or is adjacent. The outer diameter is the same at the site. The float cover 13 satisfying such external shape relationship can be molded by using a mold having a simple structure and can be easily taken out from the mold when the float cover 13 is manufactured by molding. is there.

  Exemplifying the shape of the float cover 13 that satisfies the formula (2), a cylinder having an outer periphery equal to the outer periphery of the bottom surface on the bottom surface of the spherical body, and a cylinder having the same thickness as the thickness appearing on the bottom surface is coupled. Shape.

  If the float cover has a shape satisfying the formula (2), the thickness of the cover joining portion can be increased and sufficient melt adhesive strength can be obtained.

  The main body joint portion 43 and the cover joint portion 63 may be collectively referred to as a joint portion.

  The float main body 12 and the float cover 13 are joined so that the rotation center axes of the respective cylindrical portions coincide with each other. The shape of the float is rotationally symmetric with respect to the rotation center axis.

  The cover joint portion 63 has a melting rib 66 that rises from the joint portion and goes around the inner peripheral side of the joint portion. The inner periphery of the melting rib 66 is an extended surface 65 of the inner peripheral surface 64 of the float cover 13. Here, the inner peripheral surface 64 is an inner peripheral surface of the cylindrical portion 62. On the outer peripheral side of the melting rib 66, there is a second melting surface 67 in contact with the wall surface rising from the tip end surface of the melting rib.

  The thickness of the second melting surface 67 is equal to or greater than the thickness of the outer peripheral wall 46. Here, the thickness means the radial distance of the cylindrical portion.

  The melt rib 66 faces the first melt surface 47. In the vibration fusion process described in detail later, the melting rib 66 is melted by frictional heat, and is fused and solidified on the first melting surface 47.

  The outer peripheral shape and the outer peripheral dimension of the main body joint portion 43 coincide with the outer peripheral shape and the outer peripheral dimension of the cover joint portion 63. For this reason, these joints are connected seamlessly by vibration welding. However, the height of the melting rib 66 is higher than the height of the outer peripheral wall 46, and part of the melting rib 66 remains undissolved during vibration welding, and a minute gap is formed between the tip surface of the outer peripheral wall 46 and the second melting surface 67. It is fused by leaving. Here, the minute gap is, for example, 0.3 mm to 0.7 mm.

  In the first float switch 11, an outer peripheral wall is formed at the main body joining portion, and a melting rib is formed at the cover joining portion. In the present invention, it is only necessary that an outer peripheral wall is formed at one of the joining portions and a melting rib is formed at the other joining portion. For example, a melt rib may be formed in the main body joint portion, and an outer peripheral wall may be formed in the cover joint portion.

  In the first float switch 11, the thickness (arrow 58) of the main body joint portion 43 is thicker than the thickness (arrow 78) of the cover joint portion 63. And the outer peripheral wall is formed in the main body junction part of the thicker one. A melt rib is formed in the cover joint portion having the smaller thickness. In this way, in the vibration (heat generation) process, the molten rib and the first molten surface are always in contact without repeating contact and isolation between the molten rib and the first molten surface, so that the molten rib efficiently generates and melts heat. .

  The cover joint portion 63 may be thicker than the main body joint portion 43. In this case, an outer peripheral wall is formed in the cover joint portion, and a first melt surface is formed in the main body joint portion.

  However, in the present invention, the thickness relation between the main body joint portion and the cover joint portion is an additional invention specific matter. In the present invention, the above-described thickness relationship is not necessarily required. For example, the main body joint portion and the cover joint portion may have the same thickness.

  The float body 12 and the float cover 13 are made of a thermoplastic resin. An example of the thermoplastic resin is ABS resin.

  Next, the manufacturing process of the float switch will be described.

  The switch unit is fixed and held in the float body 12. At this time, the operating shaft 19 of the switch unit is positioned parallel to the rotation center axis of the cylindrical portion, and the positioning is fixed. Usually, the operation axis and the rotation center axis are held in parallel, and preferably, the operation axis and the rotation center axis are held in a matched state.

  In this embodiment, the operation axis 19 and the rotation center axis coincide with each other. That is, a spherical float with a cylinder interposed in between, and the operating axis of the switch unit, that is, the longest dimension portion is positioned in a portion where the inner method is longer than a simple spherical shape. In this way, the resin required for the float is saved. In addition, miniaturization of the float is realized.

  Next, in a state where the float body and the float cover are held by a jig (not shown), for example, the lower jig is raised and the melting rib 66 and the first melting surface 47 are brought into contact with each other. The contact state is pressurized by a predetermined pressure, and the upper jig vibrates in this pressure state, and the melting rib and the first molten surface 47 are melted by the frictional heat generated by the vibration. Thereafter, the vibration is stopped, and the float main body and the float cover are bonded to each other while maintaining a constant pressure.

  The vibration described above may be orbital vibration or reciprocal vibration. A preferred vibration is orbital vibration. Considering that the shape of the joint portion is a hollow concentric shape, the region where the molten rib slides and melts in the reciprocating vibration has many exposed portions other than the region where the molten rib is finally welded. On the other hand, most of the region where the molten rib in the orbital vibration is melted by sliding contact is welded to the molten rib, so that there are few exposed portions other than the region where the molten rib is finally welded. Therefore, orbital vibration uses vibration energy more efficiently for welding work.

  Although the switch unit has been described as including a micro switch, it may be provided with a magnet type reed switch or a mercury switch to detect a change in the angle of the float switch and thereby output an on / off signal.

  Next, the second float switch 31 will be described. The first float switch 11 and the second float switch 31 are mainly different in the ratio and size of the spherical body and the cylindrical portion. The structure and manufacturing method of the main body joint portion of the float main body and the cover joint portion of the float cover, particularly the vibration fusion process between the float main body and the float cover, etc. are the same. Only the differences will be mainly described below. In the second float switch, the same parts and portions as those in the first float switch are denoted by the same reference numerals.

  FIG. 4 is an explanatory diagram showing the internal structure of the second float switch 31. In the second float switch 31, the shape of the float main body 32 is a combination of a spherical body and a cylindrical portion. The height of the cylindrical portion is large. Similarly, the shape of the float cover 33 is a combination of a spherical notch and a cylindrical portion. The height of the cylindrical portion is also large.

  Compared to the first float switch 11, the second float switch 31 has a larger radius of the sphere and the height of the cylinder interposed in the sphere.

  The switch unit 14 is fixed and held on the float body 32. The operation axis of the switch unit 14 coincides with the rotation center axis of the cylindrical portion in the float body.

  FIG. 5 is a schematic view showing the drainage device 1 of the sewage septic tank using the first float switch 11.

  The drainage device 1 is installed on the bottom surface in the sewage septic tank. The schematic structure of the drainage device 1 is such that a drainage pump 3 having a suction port 6 at the bottom of the drive motor 2 and a discharge port 7 at the top is connected. A water guide pipe 8 is connected to the discharge port 7. A power cable 4 is connected to the drive motor 2. Further, the drainage device 1 has a built-in control circuit (not shown), and an electric wire of the float switch 11 is connected to the control circuit. The control circuit activates the drain pump 3 when the float switch 11 reaches the upper limit position A and outputs an ON signal, and stops the drain pump 3 when the float switch 11 reaches the lower limit position B and outputs an OFF signal.

DESCRIPTION OF SYMBOLS 11 1st float switch 12 Float main body 13 Float cover 14 Switch unit 15 Micro switch 16 Operation lever 17 Weight 18 Guide cylinder 19 Operating shaft 20 Electric wire 31 2nd float switch 32 Float main body 33 Float cover 41 Spherical part 42 Cylindrical part 43 Main body joint portion 44 Outer peripheral surface 45 Extension surface 46 Outer peripheral wall 47 First melting surface 48 Vertex 51 Arrow indicating the direction from the apex to the open end 52, 53, 54 Arrow indicating the inner diameter 58 Thickness of the main body joint portion 61 Sphere missing Part 62 Cylindrical part 63 Cover joint part 64 Inner peripheral surface 65 Extension surface 66 Melting rib 67 Second melting surface 68 Vertex 69 Outer peripheral surface 71 Arrows 72 to 73 indicating the direction from the apex to the open end 72, 73, 74 Arrows indicating the inner diameter 78 Cover Joint thickness

Claims (6)

In the manufacturing method of the float switch in which the switch unit is housed in the hollow float,
The float is obtained by joining a float body holding the switch unit and a float cover,
The switch unit outputs an ON signal when the operation axis is parallel to a vertical line, and outputs an OFF signal when the operation axis is reversed.
The outer shape of the float main body is a shape in which a cylinder is coupled to the bottom surface of a sphere, and the open end of the columnar shape in the float main body is a main body joint portion.
In the float body, the switch unit is held in parallel with the rotation center axis in the cylindrical shape,
The outer shape of the float cover is a shape in which a cylinder is coupled to the bottom surface of the spherical body, and the open end of the columnar shape in the float cover is a cover joint portion.
Either the main body joint portion or the cover joint portion has an outer peripheral wall that rises from the joint portion and has an outer peripheral surface that is an extended surface of the outer peripheral surface, and has a first melt surface on the inner peripheral side in contact with the outer peripheral wall. The other has a melting rib that rises from the joint portion and has an inner peripheral surface that is an extended surface of the inner peripheral surface.
The manufacturing method of the float switch which joins the said float main body and the said float cover by making it vibrate, pressing a 1st fusion surface and the said fusion rib, and melt-bonding a 1st fusion surface and the said fusion rib. The inner shape of the float main body has an inner diameter that is larger from the apex of the spherical body shape toward the open end of the cylindrical shape, or the inner diameter is equal,
The outer shape of the float body is such that the outer diameter increases from the apex of the spherical shape to the open end of the cylindrical shape or the outer diameter is equal,
The inner shape of the float cover has an inner diameter that is increased from the apex of the spherical body shape toward the open end of the cylindrical shape, or the inner diameter is equal,
2. The method of manufacturing a float switch according to claim 1, wherein the outer shape of the float cover has an outer diameter that increases from the apex of the spherical notch shape toward the open end of the cylindrical shape, or has an equal outer diameter. .   In the main body joint portion and the cover joint portion, the outer peripheral surfaces thereof are the same, and in the main body joint portion and the cover joint portion, either one of the thicknesses is thick, and the thick joint portion has the outer periphery. The method for manufacturing a float switch according to claim 2, further comprising a wall.   The method for manufacturing a float switch according to claim 1, wherein the vibration method for vibrating the first molten surface and the molten rib while applying pressure is orbital vibration.   The method for manufacturing a float switch according to claim 1, wherein the vibration method for vibrating the first molten surface and the molten rib while applying pressure is orbital vibration. In the float switch that houses the switch unit in the hollow float,
The float is obtained by joining a float body holding the switch unit and a float cover,
The switch unit outputs an ON signal when the operation axis is parallel to a vertical line, and outputs an OFF signal when the operation axis is reversed.
The outer shape of the float main body is a shape in which a cylinder is coupled to the bottom surface of a sphere, and the open end of the columnar shape in the float main body is a main body joint portion.
In the float body, the switch unit is held in parallel with the rotation center axis in the cylindrical shape,
The outer shape of the float cover is a shape in which a cylinder is coupled to the bottom surface of the spherical body, and the open end of the columnar shape in the float cover is a cover joint portion.
Either one of the main body joint portion and the cover joint portion has an outer peripheral wall that rises from the joint portion and has an extended surface of the outer peripheral surface as its outer peripheral surface.
A float switch in which a main body joint portion and a cover joint portion are melt-bonded on the inner peripheral side in contact with the outer peripheral wall.

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