JP2012247228A - Float - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a float excellent in durability with respect to the inner pressure of a fuel tank.SOLUTION: Disclosed is a float 21 configured by welding a cup body 22 and a lid body 23, therein a cup side rib 34 installed in the cub body 22 and an annular lid side rib 47 installed in the lid body 23 are formed so as to be separate from each other in such a state that any external force does not act on the lid body 23, and so as to be brought into contact with each other in accordance with the elastic change of the lid body 23 in such a state that the external force acts. Thus, it is possible to suppress the deflection quantity of the lid body 23 which is generated when the external force acts on the lid body 23, and to reduce any stress which acts on the lid body 23 or any stress which acts on a weld. Therefore, it is possible to improve the strength of the lid body 23 or the weld. Also, since the cup body 22 and the lid body 23 are not brought into contact with each other in welding, it is possible to position the cup body 22 and the lid body 23 with high accuracy, to improve weld quality, and to improve the strength of the weld.

Description

  The present invention relates to a float that is disposed in a fuel tank that stores fuel such as gas or liquid, and floats according to the liquid level of the fuel.

  For example, a fuel tank that stores liquefied gas fuel such as liquefied petroleum gas (hereinafter referred to as LPG) or dimethyl ether (hereinafter referred to as DME) is provided with a liquid level gauge, an overfill prevention device, and the like. Liquid level gauges and overfill prevention devices generally include a float that floats with the liquid level of the fuel stored in the tank.

  As such a float, for example, the configuration of Patent Document 1 is proposed. The float of this conventional configuration is a hollow body formed by welding a lid body that closes the opening to a cylindrical cup body that is open at one end and closed at the other end, and a rib is formed inside the cup body. Has been. In this float, the strength of the cup body is improved by forming ribs.

JP 2009-56897 A

  In the above-described float, when further improvement in strength is required, it is necessary to improve not only the cup body but also the lid body. Moreover, the strength improvement of the welding part which welded the cup body and the cover body is also required.

  The present invention provides a float that can exhibit higher strength.

  The present invention comprises a cylindrical cup body having an opening at at least one end, and a disc-shaped lid body welded to the cup body to close the opening, and a liquid of fuel stored in a fuel tank In the hollow float that floats with the surface height, the cup body includes a cup side rib therein, and the lid body includes a lid side rib protruding from the inner surface of the lid toward the cup body side, The cup side rib and the lid side rib are separated from each other with no external force acting on the lid, and the cup side rib and the lid side rib are brought into contact with each other by the elastic deformation of the lid while the external force is applied. The float is characterized in that a side rib and a lid side rib are formed.

  In such a configuration, the strength of the lid itself can be improved by providing the lid-side rib. Further, when an external force is applied to the lid, the lid is elastically deformed and bent, and the stress acting on the welded portion between the lid and the cup increases. In this configuration, when the lid is elastically deformed, the lid-side rib and the cup-side rib come into contact with each other. Therefore, the amount of deflection of the lid that occurs when an external force is applied to the lid is suppressed, and the stress acting on the lid It can suppress that the stress which acts on the said welding part becomes high too much. Thereby, the intensity | strength of a cover body or a welding part can be improved.

  In addition, since the cup-side rib and the lid-side rib are not in contact with each other when no external force is applied, the lid can be accurately positioned with respect to the cup when the cup and the lid are welded. Since the cup body and the lid body can be welded accurately and sufficiently by this accurate positioning, appropriate welding can be performed stably. If the cup-side rib and the lid-side rib come into contact with each other due to variations in height, it is difficult to perform the positioning with high accuracy. In this case, since the cup body and the lid body are welded in a state where they are not accurately and sufficiently in contact with each other, the welding is insufficient and the strength of the welded portion is reduced. On the other hand, in this structure, since it can position accurately, as mentioned above, it can weld correctly and fully, and can improve the welding quality of a cup body and a cover body. Thereby, the intensity | strength of a welding part can be improved.

  In the above-described float of the present invention, a configuration is proposed in which the lid-side rib projects in an annular shape from the inner surface of the lid toward the cup body.

  In such a configuration, since the lid-side rib is formed in an annular shape, the lid-side rib and the cup-side rib come into contact with each other by elastic deformation of the lid, regardless of the circumferential positional relationship between the lid and the cup. Therefore, even if the lid body and the cup body are welded at an arbitrary position in the circumferential direction, the lid body and the stress acting on the weld body and the stress acting on the welded portion can be reduced by suppressing the deflection amount of the lid body. The effect of improving the strength of the welded portion can be exhibited.

  In the float of the present invention described above, a configuration is proposed in which the cup-side ribs are formed radially outward from the radial center of the cup body.

  In such a configuration, when the lid is elastically deformed by the internal pressure of the fuel tank due to the radial cup-side rib, the annular lid-side rib and the radial cup-side rib are dispersed and contacted in the circumferential direction. It can suppress that the stress which acts on a body, and the stress which acts on the welding part of a cover body and a cup body become large locally. Thereby, the intensity | strength of a cover body or a welding part can be improved.

  In the float of the present invention described above, the lid-side rib is formed such that the area of the lid inner surface that is radially outward of the lid-side rib and the area of the lid inner surface that is radially inner are substantially the same. Is proposed.

  In such a configuration, the area on the radially inner side and the area on the radially outer side defined by the lid rib substantially coincide with each other, so that the inner pressure of the fuel tank acts on the radially inner surface and the radially outer surface. Load to be approximately equal. Thereby, the stress which acts on a cover and a welding part can be disperse | distributed more appropriately, and the intensity | strength of a cover and a welding part can be improved.

  In the float of the present invention described above, a configuration is proposed in which the lid further includes radial ribs protruding from the inner surface of the lid toward the cup body.

  In such a configuration, the strength of the lid can be further improved by the radial ribs. In addition, when the lid is molded from resin, the occurrence of sink marks can be suppressed during molding.

  In the float of the present invention, as described above, the cup-side rib provided on the cup body and the lid-side rib provided on the lid body are separated in a state where no external force acts on the lid body, and the external force is Since it is formed so as to come into contact by elastic deformation of the lid in an acted state, the amount of deflection of the lid that occurs when an external force is applied to the lid can be suppressed, and the stress acting on the lid and the lid The stress acting on the welded portion between the cup body and the cup body can be reduced. Thereby, the intensity | strength of a cover body or a welding part can be improved. Further, since the cup-side rib and the lid-side rib do not come into contact with each other when the cup body and the lid body are welded, the lid body can be accurately positioned with respect to the cup body, and the cup body and the lid body can be accurately positioned. And since it can weld in the state which is fully contacting, the welding quality of a cup body and a cover body can be improved. Thereby, the intensity | strength of a welding part can be improved.

2 is a partial cross-sectional view of the fuel tank 1. FIG. 3 is a partial cross-sectional view of the float 21. FIG. (A) The top view of the cup body 22, and (B) MM sectional drawing in FIG. 3 (A). (A) The bottom view of the cover body 23, (B) It is PP sectional drawing in FIG. 4 (A). It is explanatory drawing which shows the state which the cover body 23 bends with external force.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The present embodiment is a fuel tank 1 disposed in a vehicle such as a truck powered by an engine driven by liquefied gas fuel. Here, for example, LPG (liquefied petroleum gas) fuel or DME (dimethyl ether) fuel is used as the liquefied gas fuel.

  As shown in FIG. 1, the fuel tank 1 includes a tank body 2, a valve device 5 that is disposed in the tank body 2 and opens and closes a valve as a filling port for liquefied gas fuel, and is disposed in the tank body 2 and liquefied gas. A level gauge 6 for measuring the fuel level level, an overfilling prevention device 7 provided inside the tank body 2 and connected to the valve device 5 to prevent the liquefied gas fuel from being filled in a predetermined amount or more, etc. Has been. Here, the level gauge 6 and the overfill prevention device 7 respectively include floats 21 and 21 that float according to the liquid level of the liquefied gas fuel, and arms 8 and 9 connected to the floats 21 and 21, respectively. The float 21 is mechanically operated by floating according to the liquid level of the liquefied gas fuel stored in the fuel tank 1. Since these liquid level gauges 6 and the overfilling prevention device 7 can be applied to those used in the past, the details thereof are omitted. Such a fuel tank 1 is disposed horizontally, for example, at the lower part of the side of the vehicle body of the truck, and is fixed to the vehicle by a fixing member (not shown).

Next, the said float 21 concerning the principal part of this invention is demonstrated.
As shown in FIG. 2, the float 21 is a hollow body formed by welding a cup body 22 and a lid body 23. In the present embodiment, the cup body 22 and the lid body 23 are molded from polyphenylene sulfide resin (hereinafter referred to as PPS resin).

  As shown in FIG. 3, the cup body 22 is formed in a cylindrical shape having an inner peripheral portion 31 formed in a cylindrical shape along the central axis L, and a cylindrical shape having the same length and the same length as the inner peripheral portion 31 and a large diameter. The outer peripheral portion 25, and the inner peripheral portion 31 and the bottom portion 26 formed so as to connect one end portion in the same direction among the end portions of the outer peripheral portion 25, the inner peripheral portion 31, A plurality of cup-side ribs 34 that connect the outer peripheral portion 25 and the bottom portion 26 are provided. The inner peripheral portion 31, the outer peripheral portion 25, the bottom portion 26, and the cup-side rib 34 are each formed with a predetermined thickness. The cup body 22 is provided with an opening 30 that is opened on the side facing the bottom portion 26, and the lid body 23 is provided at each end of the inner peripheral portion 31 and the outer peripheral portion 25 on the opening 30 side. A step is provided for fitting together. Here, in the inner peripheral portion 31 on the opening portion 30 side, a step portion 31a constituting the step is formed with a diameter smaller than the outer diameter of the inner peripheral portion 31, and the outer peripheral portion on the opening portion 30 side. 25, a step portion 25 a constituting the step is formed with a diameter larger than the inner diameter of the outer peripheral portion 25. The length dimension of the step portion 31a and the step portion 25a in the direction of the central axis L is set substantially equal to the height dimension of the lid body 23. Moreover, the said cup side rib 34 is formed radially centering on the central axis L, and is provided in four places at equal intervals in the circumferential direction. Furthermore, the inner peripheral portion 31 is provided with a hole 32 penetrating along the central axis L, and the arms 8 and 9 described above are configured in the state in which the liquid level gauge 6 and the overfill prevention device 7 are configured. Is inserted into the hole 32 and attached.

  On the other hand, as shown in FIG. 4, the lid body 23 has an inner peripheral portion 41 formed in a cylindrical shape along the central axis L, and is concentric with and has the same length dimension as the cup body 22. An outer peripheral portion 42 formed in a cylindrical shape with a large diameter, and a bottom portion 40 formed so as to connect one end portion in the same direction among the end portions of the inner peripheral portion 41 and the outer peripheral portion 42; And a plurality of lid-side ribs 47 that connect the inner peripheral portion 41, the outer peripheral portion 42, and the bottom portion 40. The inner peripheral portion 41, the outer peripheral portion 42, the bottom portion 40, and the lid side rib 47 are each formed with a predetermined thickness. The lid body 23 is set to have a shorter length in the central axis L direction than the cup body 22. The lid body 23 is formed so that the inner peripheral portion 41 and the outer peripheral portion 42 are fitted into the step portions 31 a and 25 a of the cup body 22, respectively.

  The lid-side rib 47 includes a rib 47a formed radially at the center axis L and provided at eight positions at equal intervals in the circumferential direction, and a rib 47b formed in an annular shape around the center axis L. Are integrally configured. The lid-side ribs 47 have the effect of improving the strength of the lid body 23 by the radially formed ribs 47a, and can suppress the occurrence of sink marks when the lid body 23 is molded from PPS resin.

  As shown in FIG. 2, the float 21 has the inner peripheral portion 41 and the outer peripheral portion 42 of the lid body 23 with the side on which the lid rib 47 of the lid body 23 is formed facing the opening 30 side of the cup body 22. Each of the cups 22 is formed by fitting the stepped portion 31a and the stepped portion 25a of the cup body 22 and joining the fitted portions. Here, the cup body 22 and the lid body 23 are joined together by ultrasonic welding of a portion where both are fitted together over the entire circumference. As a result, the float 21 is formed with an internal air space that is sealed inside. In addition, about ultrasonic welding, since the welding method used conventionally can be applied, the detail is abbreviate | omitted.

  The cup side rib 34 of the cup body 22 and the lid side rib 47 of the lid body 23 are separated from each other in a state where no external force acts on the lid body 23 in the float 21, and the lid body 23. The cup-side rib 34 and the lid-side rib 47 are formed so as to come into contact with each other by elastic deformation of the lid 23 in the state where an external force is applied to the lid 23. The float 21 is exposed to the liquefied gas fuel stored in the fuel tank 1 inside the fuel tank 1, and receives the internal pressure of the fuel tank 1 and the lid body 23 receives external force due to the internal pressure. Here, FIG. 5 shows a state where the lid body 23 is bent by an external force. As shown in FIG. 5, when an external force is applied to the lid body 23, the lid body 23 is elastically deformed and bent, and the stress acting on the welded portion between the lid body 23 and the cup body 22 is increased. In the float 21 of the present embodiment, the lid 23 is formed so that the lid-side rib 47 and the cup-side rib 34 come into contact with each other when the lid 23 is elastically deformed. Therefore, the lid 23 when an external force is applied to the lid 23. Therefore, it is possible to suppress the amount of deflection of the cover body 23 and the stress acting on the lid 23 and the stress acting on the welded portion from becoming too high. Thereby, the intensity | strength of the cover body 23 or a welding part can be improved.

  Further, as described above, the cup-side rib 34 and the lid-side rib 47 of the cup body 22 are separated from each other in a state where no external force is applied to the lid 23 as described above. Therefore, when the cup body 22 and the lid body 23 are welded, the lid body 23 can be accurately positioned with respect to the cup body 22. By such accurate positioning, the cup body 22 and the lid body 23 are welded in a state where the cup body 22 and the lid body 23 are accurately and sufficiently in contact with each other, so that appropriate welding can be stably performed. If the cup-side rib 34 and the lid-side rib 47 come into contact with each other due to variations in height, the inner peripheral portion 41 and the outer peripheral portion 42 of the lid body 23 and the step portion 31a of the cup body 22 will be described. , 25a cannot be securely fitted, and it is difficult to perform positioning with high accuracy. In this case, since the cup body 22 and the lid body 23 are welded in a state where the cup body 22 and the lid body 23 are not accurately and sufficiently in contact with each other, the welding is insufficient and the strength of the welded portion is reduced. On the other hand, in the float 21 of the present embodiment, accurate and sufficient welding can be performed by positioning with high accuracy, and the welding quality between the cup body 22 and the lid body 23 can be improved. Thereby, the intensity | strength of a welding part can be improved.

  Further, since the lid-side rib 47 includes the annular rib 47b centering on the central axis L as described above, the lid 23 is bent when elastically deformed by an external force as shown in FIG. Regardless of the positional relationship between the lid body 23 and the cup body 22 in the circumferential direction, the lid side rib 47 and the cup side rib 34 come into contact with each other. Thereby, even if the cup body 22 and the lid body 23 are welded at an arbitrary position in the circumferential direction, the effect of improving the strength of the lid body 23 and the welded portion described above can be exhibited.

  Further, in the annular rib 47b constituting the lid-side rib 47 of the present embodiment, the area of the lid inner surface 40a that is radially outer than the rib 47b is substantially equal to the area of the lid inner surface 40a that is radially inner. It is formed to do. Thereby, when an external force acts on the lid body 23 due to the internal pressure of the fuel tank 1, the loads acting on the radially inner surface and the radially outer surface defined by the annular rib 47b become substantially equal. Therefore, the stress acting on the lid body 23 and the welded portion can be more appropriately dispersed, and the strength of the lid body 23 and the welded portion can be improved.

  In addition, in the present embodiment, since the cup-side ribs 34 are formed radially as described above, when the lid body 23 is elastically deformed by the internal pressure of the fuel tank 1, the circle constituting the lid-side rib 47 is formed. The annular rib 47b and the radial cup-side rib 34 are dispersed and contacted in the circumferential direction. Therefore, it can suppress that the stress which acts on the cover body 23, and the stress which acts on the said attaching part become large locally. Thereby, the intensity | strength of the cover body 23 or a welding part can be improved.

  According to the float 21 of the present embodiment described above, when the lid 23 is elastically deformed by the internal pressure of the fuel tank 1, the lid-side rib 47 and the cup-side rib 34 come into contact with each other, so that an external force is applied to the lid 23. Therefore, it is possible to suppress the amount of deflection of the lid body 23 from occurring and to suppress the stress acting on the lid body 23 and the stress acting on the wearing part from becoming too high. Thereby, the intensity | strength of the cover body 23 or a welding part can be improved. Further, when the external force is not applied to the lid body 23, the lid side rib 47 and the cup side rib 34 are not in contact with each other. Therefore, when the cup body 22 and the lid body 23 are welded, the lid body 23 with respect to the cup body 22. Can be accurately positioned. By such accurate positioning, the cup body 22 and the lid body 23 can be welded in a state where the cup body 22 and the lid body 23 are accurately and sufficiently in contact with each other, so that proper welding can be stably performed, and the cup body 22 and the lid body 23 are welded. Quality can be improved. Thereby, the intensity | strength of a welding part can be improved.

  In this embodiment, the cup-side ribs 34 are formed radially at the center axis L and are provided at four locations at equal intervals in the circumferential direction. It can be changed. In addition, the radial ribs 47a constituting the lid-side rib 47 are formed radially around the central axis L and are provided at eight positions at equal intervals in the circumferential direction. The number can be changed as appropriate.

  On the other hand, such a float 21 can exhibit the effect of improving the strength of the lid body 23 and the welded portion as described above, and is provided when the fuel tank 1 stores the highly erodible DME fuel. Can exhibit the effect of improving the strength. Therefore, the float 21 of the present embodiment can be suitably used for the fuel tank 1 that stores DME fuel.

  In the above-described embodiments, the cup body and the lid body are molded from the PPS resin, but can also be molded from a material containing reinforcing fibers in the PPS resin. As the reinforcing fiber, a short fiber of glass fiber or carbon fiber is preferably used. In particular, carbon fibers having high specific strength and specific elastic modulus are preferable. By molding with a PPS resin containing reinforcing fibers, the strength of the cup body and the lid body can be further improved.

  The present invention is not limited to the above-described embodiments, and configurations other than the embodiments can be appropriately implemented within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Tank main body 21 Float 22 Cup body 23 Lid body 30 Opening part 34 Cup side rib 40a Lid inner surface 47 Lid side rib

Claims (5)

It is composed of a cylindrical cup body having an opening at at least one end, and a disc-shaped lid body that is welded to the cup body and closes the opening, and has a liquid level of the fuel stored in the fuel tank. In a hollow float that floats with it,
The cup body includes a cup-side rib therein,
The lid body includes a lid-side rib projecting from the inner surface of the lid toward the cup body side,
In a state where no external force acts on the lid body, the cup side rib and the lid side rib are separated from each other, and in a state where the external force acts, the cup side rib and the lid side rib come into contact with each other by elastic deformation of the lid body. A float in which a cup side rib and a lid side rib are formed.   The float according to claim 1, wherein the lid-side rib is formed in an annular shape from the inner surface of the lid toward the cup body.   The float according to claim 2, wherein the cup-side ribs are formed radially outward from the radial center of the cup body.   The lid-side rib is formed so that the area of the inner surface of the lid that is radially outward from the lid-side rib and the area of the inner surface of the lid that is radially inner are substantially the same. The float according to claim 3.   The float according to any one of claims 1 to 4, wherein the lid further includes radial ribs protruding from the inner surface of the lid toward the cup body.

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