DE102021124475A1 - PROCEDURE FOR MAKING A FLUID-TIGHT FITTING ON A PROFILE, PROFILE AND BATTERY BOX - Google Patents

Abstract

The present invention relates to a method for producing a fluid-tight screw connection (100) on a profile (106), a screw (102) passing through a wall (114) of the profile (106) into a chamber located behind the wall (114). (112) of the profile (106) is screwed in and thus forms a screw opening in the wall (114), a sealing compound (116) being arranged in the chamber (112), the screw (102) when screwing into the sealing compound (116 ) is screwed in and the sealing compound (116) is partially displaced by the screw (102) when screwing in and the displaced sealing compound (116) is placed around the screw (102) and in the screw opening and the screw connection (100) is thus blocked by the sealing compound ( 116) is sealed.

Description

technical field

The present invention relates to a method for producing a fluid-tight screw connection on a profile, a profile and a battery box.

State of the art

The present invention is described below mainly in connection with battery boxes for electric vehicles.

A battery box should be waterproof. For this purpose, individual parts of the battery box can be bonded together, for example, in order to create a continuous shell. For example, the individual parts can be welded.

However, a welded battery box is disruptive during maintenance work.

Alternatively, the battery box can be assembled from individual parts and then sealed with a waterproof coating. For example, the battery box can be sprayed with a wax and thus coated.

Coating is a complex process that requires strict adherence to certain parameters to ensure reliable sealing of the battery box.

The individual parts of the battery box can also be screwed together with intermediate seals. However, over time, water can penetrate the individual parts via the screw connections. To prevent water from entering, the screw connections can be sealed with the waterproof coating.

Description of the invention

It is therefore an object of the invention to provide an improved method for producing a fluid-tight screw connection on a profile, an improved profile, and an improved battery box using means that are as simple as possible in terms of construction. An improvement here can relate, for example, to improved sealing of the screw connection against the ingress of liquids and/or simplified process management.

The object is solved by the subject matter of the independent claims. Advantageous developments of the invention are specified in the dependent claims, the description and the accompanying figures.

In the approach presented here, a screw is screwed through a wall of a profile into a sealing compound arranged within the profile. The sealing compound is partially displaced by the screw. The rotation of the bolt creates friction between the sealant and the bolt, causing the sealant and bolt to heat up. Due to the local effect of heat, the sealant can be partially liquefied or plasticized and adhere to the screw. Due to a restoring force of the sealing compound, the liquid sealing compound can also penetrate into the screw connection between the screw and the profile and thus seal the screw connection. Alternatively, the restoring force can be so great that the elastic sealing compound molds the screw or the thread and thus seals the screw connection.

So that the sealing compound cannot simply escape, the sealing compound is arranged within a chamber of the profile. The chamber also limits a required amount of sealant and may contribute to weight limitation.

A method for producing a fluid-tight screw connection on a profile is presented, with a screw being screwed through a wall of the profile into a chamber of the profile located behind the wall, thus forming a screw opening in the wall, with a sealing compound being arranged in the chamber is, the screw is screwed into the sealing compound when it is screwed in and the sealing compound is partially displaced by the screw when it is screwed in and the displaced sealing compound wraps around the screw and the screw opening and the screw connection is thus sealed by the sealing compound.

Furthermore, a profile is presented with at least one chamber located behind a wall of the profile, in which case a sealing compound can be arranged so that the sealing compound can be partially displaced when a screw is screwed in and the displaced sealing compound surrounds the screw and a screw opening in the wall lays.

Furthermore, a battery box for an electric vehicle is presented, the battery box having at least one profile according to the approach presented here, wherein at least one screw is screwed through the wall of the profile into the chamber, the screw being screwed into the sealing compound and a screw connection the profile is sealed in a fluid-tight manner by the sealing compound.

A profile can be a frame profile of a battery box. The profile can consist, for example, of a metallic material, in particular an aluminum material or a steel material. The profile can be, for example, an extruded profile or an extruded profile. The profile can be an open profile or a closed profile. The profile can have an essentially constant cross-sectional geometry along a main extension direction. For weight reasons, for example, the profile can also be provided with cutouts.

The battery box can be composed of several such profiles and other individual parts. In particular, the individual parts can be pressed onto the profiles as clamping parts of the screw connection presented here. The profiles can also be connected to one another using the screw connection presented. The battery box is designed to enclose battery modules of an electric vehicle and to protect them from environmental influences and mechanical influences. The battery box can be part of a crash structure of the electric vehicle.

A chamber can be created directly during the manufacture of the profile. The chamber can be integrally connected to the profile. The chamber may extend substantially a length of the profile. At least one wall of the chamber can be formed by an outer wall of the profile. The walls of the chamber are made of the same material as the walls of the profile. If the chamber is arranged at an edge of the profile, at least two walls of the chamber can also be formed by outer walls of the profile.

A screw can be a standard screw and can be screwed into an existing thread in the wall. The screw can also be a self-tapping screw and can be screwed into a suitable core hole in the profile. The self-tapping screw can form the thread in the wall. The screw can also be a self-drilling and self-tapping screw and independently drill a hole in the wall and form the thread in it.

A sealing compound can be a permanently elastic compound. The sealant can stick to the walls of the chamber. The sealant can be placed in the chamber before the battery box is fabricated. The sealant can be pre-arranged in the chamber by a manufacturer of the profile. The sealing compound can have thermoplastic properties. The sealing compound can be heated and liquefied by friction when screwing in the screw. The liquefied sealing compound can wet the screw and develop an adhesive effect on the screw. The adhesive effect can unfold in particular when the sealing compound cools and hardens or solidifies. The liquefied sealing compound can also penetrate into the screw connection and harden there again. Alternatively or additionally, the sealing compound can be displaced laterally by the screw, in particular, and can react to the displacement with a restoring force. Due to the restoring force, the sealing compound can be pressed onto the screw and seal it on the screw. In addition, particles produced when screwing in can be bound in the sealing compound.

The screw can clamp a clamping part against the profile. The screw can also be screwed into the profile without a clamping part. The screw can also clamp several clamping parts arranged one above the other against the profile. The clamping part can be a cover or a base of the battery box, for example. A sealing compound can be arranged between the clamping part and the profile. The sealing compound can be the same sealing compound as in the chamber. The clamping part can have a screw hole through which the screw is screwed into the profile. A position of the screw connection can be determined by the screw hole in the clamping part. The screw can also be screwed through a clamping part without a hole and then screwed through the profile. A head of the screw can rest on the clamping part and press the clamping part against the profile. A sealing disk can be arranged between the head and the clamping part. The sealing washer can have a ductile material and at least partially mold a contour of the clamping part. The sealing washer can be made of an aluminum material, for example.

The sealant can also be dosed before screwing into the chamber. The sealant can be dosed in a free-flowing or pasty state. For this purpose, the sealing compound can, for example, be heated and then cooled and hardened in the chamber. The sealant can be dosed into the cut profile. The sealant can be dosed using a dosing device. The sealing compound can be introduced into the chamber through a nozzle arranged on an end face of the profile. Alternatively, the sealing compound can be dosed by a lance pushed into the chamber. The nozzle can be arranged at the end of the lance. The lance can be moved along the chamber while the sealant is metered. In particular, the sealing compound can be dosed while the lance is being withdrawn from the chamber.

The chamber can be essentially completely filled with the sealing compound during dosing. The sealing compound can be filled from one end of the chamber to the other end of the chamber. This allows fluid tight fittings to be made anywhere along the length of the chamber.

The sealant can be dosed locally in the area of the screw connection in the chamber. The position of the screw connection can be predefined. The sealant can be dosed as a portion at the position of the screw connection. Thus, air or an inert gas can be arranged in the chamber between the portions. Sealing compound can be saved by portions distributed along the chamber. The chamber can only be filled in the area around the screw connection. A predetermined distance can be filled with the sealing compound before and after the screw connection. For example, the nozzle or lance can be pulled through the chamber and sealing compound can be dosed from the nozzle or lance into the chamber in the area of the screw connection. Dosing can be interrupted between two screw connections.

The sealing compound can be metered into the chamber through a profile opening of the profile running along the chamber. A profile opening can extend along the chamber. The profile opening breaks through a wall of the chamber and also an outer wall of the profile. The wall of the chamber can also be the outer wall of the profile. The wall of the chamber and the outer wall of the profile can also be spaced apart. Then the profile opening can have walls connecting the wall of the chamber to the outer wall of the profile. The walls of the chamber are essentially C-shaped due to the profile opening. An application nozzle can be inserted through the profile opening into the chamber to dose the sealant. In this case, the sealing compound can be metered into the chamber, in particular locally in the area of the screw connection. The application nozzle can be moved along the profile opening during dosing and sealant can be dosed from the application nozzle into the chamber in the area of the screw connection.

A butyl material can be dosed into the chamber as a sealing compound. Butyl or a butyl material is permanently elastic and has good adhesion to metal, particularly at elevated temperatures. The butyl material can be easily dosed from a nozzle. For this purpose, the butyl material can be heated to a temperature between 130°C and 150°C, for example. When heated, the butyl material is pasty and plastically deformable. The butyl material can cool down again in the chamber and harden to a permanently elastic state. The butyl material is reusable. Alternatively, foam rubber can be used as a sealing compound.

When screwed in, the screw can laterally displace a material of the wall, pierce the wall and form a thread in the displaced material. The screw can be a flow drill screw. A tip of the screw can be placed on the continuous wall of the profile, rotated and pressed against the wall. The wall is heated locally by friction until the metal material of the profile becomes fluid. The pressure causes the tip to displace the material of the wall laterally, forming an annular thickening of the wall as the wall is penetrated. Ideally, penetration is chipless. Once the tip has passed through the wall, it penetrates the underlying sealant and essentially displaces it laterally. Any shavings that may occur during penetration can be embedded in the chamber by the sealing compound. A shank of the screw adjoining the tip has a conical external thread which presses or forms an internal thread into the thickening which is still free-flowing. Ideally, the thread is also formed without cutting. Any chips produced when forming the thread can be embedded in the chamber by the sealant. A cylindrical part of the external thread adjoining the conical thread engages in the freshly formed internal thread and pulls a screw head of the screw adjoining the cylindrical thread in the direction of the profile. A clamping part arranged between the screw head and the thread can be pressed against the profile. The hot tip and the conical part of the thread, which is also heated, heat the sealant as it penetrates. Friction between the entire bolt and the sealant further increases the heating of the sealant. The sealant is locally liquefied and wets the hot screw. The lateral displacement of the liquid sealant is impeded by adjacent cold sealant and high pressure is created in the liquid sealant. Due to the high pressure, the liquid sealant is also pressed into a gap between the internal thread of the profile and the external thread of the screw and thus permanently seals the screw connection.

character list

• 1 eine Schnittdarstellung einer fluiddichten Verschraubung gemäß einem Ausführungsbeispiel; und
• 2 eine Darstellung eines Dosierens von Dichtmasse gemäß einem Ausführungsbeispiel.

An advantageous exemplary embodiment of the invention is explained below with reference to the accompanying figures. It shows:

• 1 a sectional view of a fluid-tight screw connection according to an embodiment; and
• 2 a representation of a dosing of sealing compound according to an embodiment.

The figures are only schematic representations and only served to explain the invention. Elements that are the same or have the same effect are provided with the same reference symbols throughout.

Detailed description

1 shows a sectional view of a fluid-tight screw connection 100 according to an embodiment. A screw 102 is screwed into a screw hole of a profile 106 on the screw connection 100 . The screw 102 has an external thread. The screw hole has an internal thread 104 . The profile 106 is a frame profile of a battery box 108 for an electric vehicle. The screw 102 presses a clamping part 110 against the profile 106. The clamping part 110 is, for example, a cover of the battery box 108.

The profile 106 is an extruded profile or an extruded profile made of an aluminum material or a steel material. The profile 106 has an essentially unchanged cross section along its main extension direction. The profile 106 can also have bends, for example, in the area of which the cross section can be changed.

The profile 106 has a chamber 112 which extends over the entire length of the profile 106 . At least one wall 114 of the chamber 112 is an outer wall of the profile 106. The screw hole is in the wall 114. At the screw connection 100, the screw 102 is screwed through the clamping part 110 and through the wall 114 into the chamber 112. Internal threads 104 are formed in wall 114 . The clamping part 110 is pressed against this wall 114 by the screw 102 .

In the approach presented here, a sealing compound 116 is arranged in the chamber 112 at least in the area of the screw connection 100 . The screw 102 is screwed into the sealing compound 116 . The screw 102 has at least partially displaced the sealing compound 116 laterally. The displaced sealing compound 116 rests against the screw 102 and the screw hole and seals the screw connection 100 in a fluid-tight manner.

When the screw 102 is screwed into the sealing compound 116, the sealing compound 116 has been heated at least by friction between the sealing compound 116 and the screw 102 and has at least partially liquefied in the process. In the liquid state, the sealing compound 116 has wetted the screw 102 and has penetrated at least partially into the thread turns between the internal thread 104 and the screw 102 . The sealing compound 116 adheres to a surface of the screw 102 and the internal thread 104 and thus seals the threads.

In one embodiment, the fitting 100 is a direct fitting. In the case of the direct screw connection, the screw 102 has penetrated the wall 114 that has not been pre-drilled, thereby forming the screw hole and the internal thread 104 . In the case of direct screwing, the screw 102 can also optionally penetrate the clamping part 110 first. In the example shown, however, the clamping part 110 has a through hole. The screw 102 has been placed on the profile 106 for direct screwing within the through hole and has been set in rotation. The screw 102 can penetrate the wall 114 without cutting or by cutting. The sealing compound 116 arranged behind the wall 114 permanently binds the chips that may occur during direct screwing.

When penetrating the wall 114 the screw 102 and the wall 114 are heated by friction between the screw 102 and the wall 114 . The heated wall 114 softens, allowing the screw 102 to penetrate. Upon penetration, the screw 102 displaces the metal material of the wall 114 aside and an annular thickening 118 is formed in the wall. The screw 102 forms the internal thread 104 in the inside of the thickening 118. The heated screw 102 then penetrates into the sealing compound 116, which has already been heated proportionately by the heated wall 114. The sealing compound 116 can become thin and wet the screw 102 and the internal thread 104 particularly well. The binding of the chips also works particularly well with the thin liquid sealing compound 116.

In one embodiment, profile 106 is cut with empty chamber 112 to the required length for battery box 108 and then sealant 116 is metered into chamber 112 before bolting 100 is performed. The sealing compound 116 can be metered into the chamber 112 via the open ends of the chamber 112 .

In one embodiment, a lance with a nozzle at the end is inserted into the chamber 112 from one side and pushed through to the other side. The sealing compound 116 is then metered out of the nozzle and the lance is drawn back through the chamber 112 at a predetermined speed. The speed is so great that the sealing compound 116 flowing out of the nozzle fills the entire cross section of the Chamber 112 fills up. As a result, pores and air inclusions in the sealing compound 116 can be essentially prevented. Before dosing begins, the other end of the chamber 112 can be closed in order to prevent the sealing compound 116 from escaping.

In one embodiment, the lance is withdrawn through chamber 112 and sealant 116 is metered into areas of prospective fasteners 100 . One portion of the sealing compound 116 is metered in each case for each screw connection 100 . A portion fills the cross-section of the chamber 112 from just before the screw connection 100 to just behind the screw connection 100. Between the screw connections 100, the chamber 112 remains empty. In this way, the amount of sealing compound 116 used can be reduced compared to completely filling the chamber 112 .

In one exemplary embodiment, a butyl material is metered into chamber 112 as sealing compound 116 . The butyl material is dosed with an increased temperature. Due to the increased temperature, the butyl material is at least viscous or pasty and can plastically fill the cross section of the chamber. In addition, the butyl material has good adhesion to the walls of the chamber 112 due to the increased temperature. The butyl material remains permanently elastic when it cools down to ambient temperature, but can no longer be plastically deformed. Due to the heating when screwing in the screw 102, the butyl material becomes plastically deformable again and adheres well to the screw 102.

2 11 shows an illustration of dosing of sealing compound 116 according to an exemplary embodiment. As in 1 the sealing compound 116 is metered into a chamber 112 running along a profile 106 . In contrast to the representation in 1 the profile 106 here has a profile opening 200 running along the chamber 112 . The profile opening 200 allows access to the chamber 112 at any point of the profile 106.

For dosing, an application nozzle 202 or filling nozzle is inserted through the profile opening 200 from the outside and the sealing compound is dosed into the chamber 112 .

In one embodiment, the application nozzle 202 is inserted into the chamber 112 at one end of the profile 106, dosing is started, and the application nozzle 202 is moved along the profile opening 200 to the other end of the profile 106 during dosing. In the process, the chamber 112 is completely filled with the sealing compound 116 .

In an alternative exemplary embodiment, the sealing compound 116 is only dosed in areas of future screw connections. When the application nozzle 202 moves along the profile opening 200, dosing starts shortly before the screw connection and the dosing stops just after the screw connection or is interrupted until just before the next screw connection. The chamber 112 remains empty between the screw connections. The application nozzle 202 can be moved along the profile opening 200 at a constant speed.

In other words, a direct screw connection is sealed by a profile previously filled with a sealing compound.

In the case of direct screw connections, the tightness of the thread formed by the direct screw connection cannot be guaranteed. In the case of battery systems, however, this tightness function is relevant and even relevant to safety. Available screwing systems, i.e. screws and profiles in which the screwing is carried out, as well as the procedural screwing techniques, cannot provide 100% security with regard to tightness.

The approach presented here ensures that the required sealing takes place in the thread formed by the direct screw connection.

By filling a sealing compound into a chamber provided for this purpose in a frame profile, in which the screwing takes place later, it is ensured that the freshly formed thread is automatically sealed during the screwing process. Dipping the screw in the sealing compound prevents water from penetrating the thread formed by the direct screw connection.

If butyl is used as the sealing compound, the heat generated by the friction created during thread forming simultaneously softens the surrounding butyl compound and sticks to the screw. The butyl adhesion improves as the temperature rises. But this also applies to other sealants.

Spraying the surface with e.g. wax or other sealing spray masses is no longer necessary. High-quality results can be achieved through the direct screwing into the sealing compound presented here. The effort involved is very low. The process is very stable and good reproducibility is achieved.

The approach presented here can be applied in particular to battery systems, but can also be used in other areas. Included a high level of process reliability and, under standard industrialization aspects, very good feasibility and functional guarantee can be achieved. The direct screw connection in a chamber provided with sealing compound is a tolerance-neutral, space-saving, dirt-free solution that is independent of the screw type. A high level of technical cleanliness (TECSA) can be achieved by fixing and embedding any chips that may occur during drilling and thread forming with the self-tapping and tapping screw.

Since the devices and methods described in detail above are exemplary embodiments, they can be modified to a large extent in the usual way by a person skilled in the art without departing from the scope of the invention. In particular, the mechanical arrangements and the size ratios of the individual elements to one another are merely exemplary

reference list

100

screw connection

102

screw

104

inner thread

106

profile

108

battery box

110

clamping part

112

chamber

114

Wall

116

sealant

118

thickening

200

profile opening

202

application nozzle

Claims (9)

Method for producing a fluid-tight screw connection (100) on a profile (106), with a screw (102) passing through a wall (114) of the profile (106) into a chamber (112) of the profile (106) located behind the wall (114). ) is screwed in and thus forms a screw opening in the wall (114), a sealing compound (116) being arranged in the chamber (112), the screw (102) being screwed into the sealing compound (116) when it is screwed in, and the sealing compound ( 116) is partially displaced by the screw (102) when it is screwed in and the displaced sealing compound (116) wraps itself around the screw (102) and the screw opening, and the screw connection (100) is thus sealed by the sealing compound (116). procedure according to claim 1 , in which the sealing compound (116) is metered into the chamber (112) before it is screwed in. procedure according to claim 2 , in which the chamber (112) is essentially completely filled with the sealing compound (116) during dosing. procedure according to claim 2 , in which the sealing compound (116) is dosed locally in the area of the screw connection (100) into the chamber (112). Method according to one of claims 2 until 4 , in which the sealing compound (116) is metered into the chamber (112) through a profile opening (200) of the profile (106) running along the chamber (112). A method according to any one of the preceding claims, wherein the sealant (116) is a butyl material. A method according to any one of the preceding claims, wherein the screw (102), when screwed in, laterally displaces a material of the wall (114), pierces the wall (114) and forms internal threads (104) in the displaced material. Profile (106) with at least one chamber (112) located behind a wall (114) of the profile (106), wherein a sealing compound (116) can be arranged in the chamber (112), so that the sealing compound (116) when screwing in a screw (102) is partially displaceable and the displaced sealing compound (116) is placed around the screw (102) and a screw opening in the wall (114). Battery box (108) for an electric vehicle, wherein the battery box (108) according to at least one profile (106). claim 8 has, wherein at least one screw (102) is screwed through the wall (114) into the chamber (112), wherein the screw (102) is screwed into the sealing compound (116) and a screw connection (100) on the profile (106 ) is sealed fluid-tight by the sealing compound (116).

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