DE102006024767B4 - Method and device for connecting a plastic cover to a metal housing - Google Patents

Abstract

Method for the positive connection of a metallic component with a plastic component, preferably a metallic housing (10) with a housing cover (11) made of a plastic material, wherein the housing (10) has a groove (12) into which the housing cover (11) for closing a housing inner side (13) is positively inserted, wherein the method comprises the following steps:
- Inserting the housing cover (11) in the opening to be closed of the housing (10), wherein the plastic material of the housing cover (11) has a solid state of matter;
- Introducing a quantity of heat in the plastic material of the housing cover (11), which is transferred by the introduction of heat at least marginally adjacent to the housing (10) in a plasticized material state;
- Axial Nachschieben the housing cover (11) in the direction of the housing inner side (13);
- Penetration of the plastic material of the housing cover (11) in the groove (12), which is caused by a displacement of the plasticized plastic material due to the axial Nachschiebens; and
- solidification of the plastic material of the ...

Description

The The present invention relates to a method for positive connection a metallic component with a plastic component, preferably a metallic housing with a housing cover of a plastic material, the housing having a groove into which the housing cover to close a housing inside form-fitting is introduced, and such a positive connection.

method for positive locking Joining of plastic components in a metallic component are in particular from the field of Automotive engineering well known. The procedure often takes place there Application where a housing made of a metallic component and exposed to high forces is, in conclusion the housing with a housing cover is closed. The resulting bond between the metallic casing as well as the housing cover made of a plastic material has to meet many demands become. In addition to a required tightness for pressure-tight sealing of Housing inside concern the claims still a small component size, a high temperature resistance for example, from -40 ° C to 120 ° C, wherein continue low process costs and a high and process-safe Quality assured have to be. The housing can Components concern, for example, liquid container, housing of Include relays, electrical or electronic circuits or the case of Represent sensors or mechanical elements. Become frequent the housings completed by automated manufacturing and assembly, initially in the housing the male components are added to finally the casing with the housing cover to close.

Around the requirements in terms of small component size, low cost and To meet the high process reliability, more and more metal components replaced by plastic components. For reasons of power transmission However, there are many cases continue for the most part made of metal and the less loaded housing parts are made for cost reasons made of a plastic material. The Production of the bond between the metallic housing as well the housing cover made of a plastic material is usually done by screwing or by riveting and other additional connecting means. The connections ensure a backlash-free process-reliable connection via a long service life of the vehicle. Due to the additional components, such as screws, However, rivets or other connecting means arise additional Cost, and the fasteners must be in the space of the vehicle to get integrated. The one for it necessary additional space for a flange or screw heads, etc. can respect the integration of components in the vehicle cause problems often not the required space is available.

There are z. B. from the DE 101 48 493 A1 Also known connections between metallic housing components and plastic components, which are based on snap connections. These connections initially require no additional components. However, the strength and thermal expansion of the plastic components must be adapted to the metallic components against the background of occurring temperature and force loads. This is often achieved by fiber reinforcement of the plastic material, but thereby decreases the elasticity of the plastic material. However, a snap connection is based on the elasticity of the plastic material, which is reduced by a fiber-reinforced plastic in terms of their reliability. This lack of elasticity must therefore be compensated by a longer travel, which, however, again important space is lost by the correspondingly larger dimensions of the components in the vehicle. After frequently occurring thermal cycling, especially in the engine compartment of the vehicle, the snap connections are often no longer free of play or were even immediately after the assembly with game afflicted. This game leads to unpleasant noises in the vehicle and is rejected by the user or perceived as a lesser quality.

It is therefore the object of the present invention, a method to create, which is the production of a composite of a metallic component with a component made of a plastic material without additional elements allows one takes up little space and has a high process reliability. It is a further object of the present invention to provide a corresponding positive connection to accomplish.

These Task is based on a method for positive connection a metallic component with a plastic component with the Characteristics of claim 1 solved. Regarding the positive Composite, the object is achieved by the features of claim 11.

advantageous Further developments of the invention are specified in the dependent claims.

The invention includes the technical teaching that the method comprises the following steps: inserting the housing cover in the opening to be closed of the housing, wherein the plastic material of the housing cover has a solid state, the introduction of a quantity of heat in the plastic material of the Gehäusede This is transferred by the introduction of heat at least marginally adjacent to the housing in a plasticized material state, an axial Nachschieben the housing cover in the direction of the housing interior, the penetration of the plastic material of the housing cover into the groove, which due to displacement of the plasticized plastic material due the axial Nachschiebens is effected, and the solidification of the plastic material of the housing cover by termination of the heat input, wherein the plasticized plastic material within the groove remains in the housing and a positive connection is formed.

The The invention is based on the idea of joining a housing cover in a groove of a housing in a manner known per se to expand to a randseitiges Plasticizing the plastic material of the housing cover temporarily to produce, and this in the plasticized material state in the groove to press into it. By a subsequent Solidification of the plastic material in the groove creates a positive connection between the housing cover as well as the housing, without that an additional Connecting means is required. The generation of positive connection is not due to elastic deformation of areas of the housing cover as well as a subsequent one Snaps into the intended groove in the housing, but uses one temporary change the material state of the plastic material of the housing cover, so that this in the undercut formed by the groove in the casing is introduced. The axial Nachschieben the housing cover in the direction of the inside of the housing moves first the housing cover in the case into it. The inner contour of the housing has adjacent to the groove a radially inwardly formed projection on, leaving the case lid not merely pushed towards the inside of the housing becomes. The axial Nachschieben is in the plasticized area of the housing cover generates a transverse expansion, so that by an axial force a radial flow of material is generated in the groove. Due to the diameter jump in the interior of the housing a stop edge is formed, so that the housing cover is not uncontrolled in the inside of the housing pushed in, but is held by the stop edge. The axial Nachschieben takes place by means of a force in the housing cover from the housing cover outside, which is done for example by a device which in the housing cover initiates a defined hub. This hub can, for example be wegbegrenzt, but also a force control is possible, so that when reaching a maximum pressing force of the stroke is limited.

A further advantageous embodiment of the present invention provides that the heat for transferring the plastic material of the housing cover from the solid to the plasticized material state by means of an ultrasound effect is introduced. Ultrasonic bonding is a form of joining by Friction, in the present case, the housing is firmly clamped, while the housing cover is vibrated by an ultrasonic resonator and simultaneously against the case is pressed. At the contact point is the plastic material by the friction against the housing heated so much that it melts at least at the edges, so that the plastic material is transferred to the plasticized material state and through the applied force is pressed into the groove.

During the Plasticizing the plastic material is the housing cover pushed axially, the required for generating the frictional heat Contact force on the force is based, which also the axial retightening of the housing cover effected in the direction of the inside of the housing. Thus, the advantage is achieved that no further aid to produce the composite material is required, and a single application of force at the same time for friction heat generation as well as for material flow of the plastic material can be used.

According to one another embodiment of the Invention is provided that the introduction of the amount of heat in the plastic material of the housing cover before and / or during the axial Nachschiebens the housing cover in the opening of the housing he follows. With regard to the process, there is the possibility the action of the ultrasound for heat input during the provide total axial Nachschiebebewegung the housing cover, wherein the ultrasonic generator only at or after the end of the force on the housing cover is ended. Alternatively it can be provided, a plasticizing to produce the plastic material, only then to the Ultrasonic action to initiate the axial Nachschiebebewegung.

In order to create an enlarged sealing effect, it can be provided that the groove is designed as a labyrinth contour into which the plastic material of the housing cover penetrates. The groove in the housing is initially arranged unchanged, and forms adjacent to the housing end an undercut. However, the groove comprises a plurality of mutually parallel grooves, which form a meander contour in cross-section. Now, if the plastic material is pressed radially into the grooves, they are filled with the plastic material of the housing cover, resulting in an enlarged contact surface between the inside of the housing as well forms the region of the plasticized or re-solidified plastic material of the housing cover. Due to a possible shrinkage of the plastic material due to the change in the material state, the formation of a meandering shape in the form of a labyrinth contour can have an advantageous effect, since it still retains a high sealing effect even with a slight retraction of the plastic material in the radially inwardly directed side. In particular, due to the different thermal expansion of the materials used from the metal housing and the plastic lid, there may be small gaps between the components, which do not meet all the tightness requirements. However, it is possible to maintain the required sealing effect by means of the proposed labyrinth contour. The housing and the housing cover can be designed radially symmetrical, wherein the positive connection also rotates radially.

A further advantageous embodiment The present invention provides that between the housing and the housing cover at least before joining a sealing element is used to achieve an increased sealing effect. In addition to the application of the labyrinth contour as a groove in the housing supports a additional Sealing element the required sealing effect in addition. The sealing element can an O-ring, which is inserted into a groove, the outside encircling the housing cover is introduced. Now, if the housing cover is inserted into the housing, so seals the O-ring against the inside of the housing. The function as well as the Training of the sealing element remains of the ultrasonic effect during the joining process unaffected.

advantageously, has the groove of the housing at least one radial position on a bulge, in which the plasticized plastic material of the housing cover is pressed, around a rotation of the housing cover in the case too create. While of the joining process is the plasticized plastic material of the housing cover in the bulge is dented and freezes in this. This forms the solidified plastic material a nose, which engages positively in the bulge and an anti-rotation forms. Thus, the radial position of the housing cover in the housing is not changeable, what further security against a loosening of the housing cover and a possible rattling prevented.

A further advantageous embodiment of the Invention provides that the housing cover with at least one Predetermined breaking point executed is after the production of the positive joint connection, a release of the housing cover out of the case to allow by breaking the breaking point. The breaking point can in the housing cover even be designed so that these by an external force destroyed can be so that the cover without damaging the case this is again removed. To re-close the housing can a new housing cover which is used in the same way as described above is added into the housing.

The The present invention further relates to a positive connection a housing cover made of a plastic material with a metallic housing, wherein the composite is produced by means of the aforementioned method. The form-fitting Composite may be, for example, a servo cover and a servo housing for an automobile. Furthermore, the housing cover described can advantageously be used as sensor cover in electric steering systems.

Further, the invention improving measures are in the subclaims stated below or together with the description a preferred embodiment of the Invention with reference to the figures shown. Show it:

1 a cross section of the housing and the housing cover before the production of the joint connection;

2 a cross section of the housing and the housing cover after the production of the joint connection;

3 a cross section of the housing and the housing cover, wherein the groove is formed in the housing as a labyrinth contour;

4a a view of the housing with a recess adjacent to the groove;

4b a cross section of the region of the housing according to 4a wherein the plastic material of the housing cover is pressed into the recess; and

5 a housing cover with segments, which produce a positive connection with the housing in the segment area.

at The figures are merely an exemplary technical execution of the present invention.

This in 1 shown housing 10 is shown in cross-section, with only the cutout is shown, in which the housing cover 11 is used. The housing cover 11 is also in Cross section shown, wherein this is shown in the state before the production of the joint connection. The outer contour of the housing cover 11 initially has a cylindrical portion, and is bounded by a jump to a smaller diameter, wherein the diameter jump has an undercut, so that the housing cover 11 in the case 10 by means of a circumferential edge 19 is axially supported. This edge 19 represents a line contact with the housing. The housing 10 has a circumferential groove 12 on, wherein the line contact of the housing cover 11 in the side area of the groove 12 is trained. The diameter step on the housing cover 11 centers this in the housing 10 on the diameter of the room 15 , wherein the housing cover 11 even having a cut, leaving the room 15 in unassembled state comprises a circumferential small gap. This small gap prevents the penetration of the plasticized plastic material into the room 15 and on to the sealing element 18 , In the room 15 is the insertion bevel for the sealing element 18 provided and at the same time the end stop for the lid movement. In the cylindrical section of the housing cover 11 is a sealing element 18 used, this being used in a circumferential receiving groove. Thus, the housing cover 11 outside a housing cover outside 14 on, and limits a housing inside 13 , The introduction of force to generate the friction between the housing cover 11 and the housing 10 during the ultrasound action is on the housing cover outside 14 produced, which also has a negative pressure in the inside of the housing 13 represents a possibility of force introduction, in which the housing cover 11 in the case 10 is sucked in.

2 shows the case 10 as well as the housing cover 11 in a joined state. The plastic material of the housing cover 11 has been plasticized and has been in the groove 12 pressed. Because the groove 12 an undercut in the housing 10 represents is a positive connection between the housing cover 11 as well as the housing 10 been generated. The space 15 is only through the insertion bevel for the sealing element 18 formed and otherwise provides the end stop for the movement of the housing cover 11 As in the 2 shown, the sealing element remains 18 unchanged in its state, and provides an additional sealing effect to seal the inside of the housing 13 , The introduction of force into the housing cover 11 takes place via the housing cover outside 14 so that the housing cover 11 in the case 10 is indented. Thus, the housing forms 10 - Right side in the image plane - the completion of the joint assembly, so that the housing cover 11 in its horizontal extent within the housing 10 is introduced.

3 shows a further embodiment of the housing 10 with a labyrinth contour 16 the groove 12 , The labyrinth contour 16 includes three circumferentially in the housing 10 introduced notches, which in each case by the pressing with plastic material of the housing cover 11 are filled. For an increased sealing effect is achieved, so that the sealing element 18 can be omitted, with a combination of the labyrinth contour 16 with the sealing element 18 is possible.

The 4a and 4b show a bulge 17 in the area of the groove 12 in the case 10 , which as anti-rotation of the housing cover 11 in the case 10 acts. Will the plastic material of the housing cover 11 plasticized by the action of ultrasound, so the plastic material is both in the groove by the axial supply movement 12 as well as in the bulge 17 pressed. This can be single or multiple on the perimeter of the case 10 be formed, with the bulge 17 and the molded plastic material in this form a positive rotation, wherein the radial position of the housing cover 11 either technically necessary, or the anti-rotation creates through the bulge 17 Another security against loosening the housing cover 11 ,

The 5 shows a housing cover 11 where the edge 19 is not circumferential, but only in segments 20 is available. Due to the segments, the strength of the connection is lower and can be reduced by appropriate design and number to the necessary size. By attaching one or more predetermined breaking points in the segment area, the destructive disassembly of the housing cover without the destruction of the housing is easily possible

10

casing

11

housing cover

12

groove

13

Housing inside

14

Cover outside

15

plenum

16

labyrinth contour

17

bulge

18

sealing element

19

edge

20

segment

Claims (18)

Method for the positive connection of a metallic component with a plastic component, preferably a metallic housing ( 10 ) with a housing cover ( 11 ) made of a plastic material, wherein the housing ( 10 ) a groove ( 12 ) on indicates in which of the housing cover ( 11 ) for closing a housing inside ( 13 ) is introduced in a form-fitting manner, wherein the method comprises the following steps: - Inserting the housing cover ( 11 ) in the opening of the housing to be closed ( 10 ), wherein the plastic material of the housing cover ( 11 ) has a solid state of matter; Introducing a quantity of heat into the plastic material of the housing cover ( 11 ), this being at least peripherally adjacent to the housing by the introduction of the heat ( 10 ) is converted into a plasticized material state; - axial Nachschieben the housing cover ( 11 ) in the direction of the inside of the housing ( 13 ); - penetration of the plastic material of the housing cover ( 11 ) into the groove ( 12 ), which is caused by a displacement of the plasticized plastic material due to the axial Nachschiebens; and - solidification of the plastic material of the housing cover ( 11 ) by termination of the heat input, wherein the plasticized plastic material within the groove ( 12 ) in the housing ( 10 ) remains and a positive connection is formed. A method according to claim 1, characterized in that the axial Nachschieben by means of an introduction of force into the housing cover ( 11 ) is effected, wherein the force introduction via the housing cover outside ( 14 ) he follows. A method according to claim 1 or 2, characterized in that the heat for transferring the plastic material of the housing cover ( 11 ) is introduced from the solid to the plasticized material state by means of an ultrasonic effect. Method according to one of the preceding claims, characterized in that the housing cover ( 11 ) before the action of ultrasound in the axial direction only with the edge ( 19 ) on the housing ( 10 ). Method according to one of the preceding claims, characterized in that the housing ( 10 ) adjacent to the groove ( 12 ) a room ( 15 ), which by the axial Nachschieben the housing cover ( 11 ) becomes smaller and forms an end stop of the lid movement. Method according to one of the preceding claims, characterized in that the introduction of the amount of heat in the plastic material of the housing cover ( 11 ) before and / or during the axial Nachschiebens the housing cover ( 11 ) in the opening of the housing ( 10 ) he follows. Method according to one of the preceding claims, characterized in that the groove ( 12 ) as a labyrinth contour ( 16 ) is carried out, in which the plastic material of the housing cover ( 11 ) penetrates to provide an increased sealing effect. Method according to one of the preceding claims, characterized in that the groove ( 12 ) of the housing ( 10 ) at at least one radial position a bulge ( 17 ), in which the plasticized plastic material of the housing cover ( 11 ) is pressed to prevent rotation of the housing cover ( 11 ) in the housing ( 10 ) to accomplish. Method according to one of the preceding claims, characterized in that between the housing ( 10 ) and the housing cover ( 11 ) before joining at least one sealing element ( 18 ) is used to achieve an increased sealing effect. Method according to one of the preceding claims, characterized in that by the heat input more plastic material of the housing cover ( 11 ) than in the groove ( 12 ) flows to create a play-free composite. Positive connection of a housing cover ( 11 ) made of a plastic material with a metallic housing ( 10 ), wherein the composite is produced by means of a method according to one of claims 1 to 10. Positive-locking composite according to claim 11, characterized in that the housing cover ( 11 ) consists of a polyamide. Positive-locking composite according to claim 11, characterized in that the housing ( 10 ) is a steering housing made of aluminum. Positive-locking composite according to claim 11, characterized in that the housing ( 10 ) adjacent to the groove ( 12 ) a room ( 15 ), which is closed to the molten plastic by the housing shoulder and the housing cover paragraph and the seal ( 18 ) protects against the liquid plastic. Positive-locking composite according to claim 11, characterized in that the housing ( 10 ) adjacent to the groove ( 12 ) a room ( 15 ), which has an insertion bevel for the sealing element 18 having. Positive-locking composite according to claim 11, characterized in that the housing ( 10 ) and the housing cover ( 11 ) are designed radially symmetrically, and radially rotate the positive connection. Positive-locking composite according to patent claim 11, characterized in that the housing cover ( 11 ) is carried out with at least one predetermined breaking point in order, after the production of the positive-fit joint connection, to release the housing cover ( 11 ) out of the housing ( 10 ) by breaking the predetermined breaking point. Positive-locking composite according to claim 11, characterized in that the edge ( 19 ) from the housing cover ( 11 ) on segments ( 20 ) is available.