DE102004003464A1 - Method for producing a throttle valve unit with increased tightness - Google Patents

Abstract

The invention relates to a method for producing a throttle valve unit, a housing part (10, 13, 53) and a flap part (17) movable relative thereto. First, the housing part (10, 13, 53) is injection molded in a first cavity of a first plastic material. The projection part (41) obtained in accordance with this method step is transferred into a second cavity (42) spatially separated from the first cavity. Within the second cavity (42), a movable flap portion (17) of a second plastic material (57) within the pre-molded part (41) is injection-molded. In this case, a cooling of the second spray station (40). Subsequently, a third material is introduced into the gap geometries (61, 62) of the two-component injection-molded part (60), wherein the gap geometries (61, 62) outside the introduction of the third material outside the leak specification and thereafter, if necessary, partial removal of the third Materials within the required tightness specification.

Description

technical area

in the Automotive sector throttle units are increased today as plastic injection molded components in large series manufactured. Such throttle body units are For example, produced by injection molding valve housing velvet in the case injected flaps. The throttle body units used in the automotive sector are used, are exposed to temperatures between minus 40 ° C and 120 ° C, so worry about that is to bear that in this temperature range, the functionality of the Moldings with respect to gap widths achievable by injection molding to ensure is.

State of technology

EP 0 482 272 A1 refers to a flap unit. There is disclosed a flapper apparatus and a method of manufacturing a moveable flap in a housing that houses the moveable flap. The flap and the valve body are made in one and the same tool. In a first injection molding step, the housing is produced and in a subsequent injection molding step, the disk-shaped flap is molded therein. At the relatively movable to the housing flaps sealing portions are formed, which cooperate sealingly with housing portions of the valve body. The flap is preferably one which is of the butterfly type and the flap housing is one which accommodates a butterfly-shaped flap. With the disclosed manufacturing method, a much cheaper production of a flap device for the automotive sector can be achieved. The position of the flap and its housing position are fixed in this embodiment to the transverse position to the air passage direction.

US 5,304,336 also relates to a method of manufacturing a device. This device includes a movable part and a housing for receiving the movable part. The movable part and the housing are manufactured by means of injection molding by sequential manufacturing steps. Preferably, the housing is injection molded in a first process step, while the relatively movable to the housing part is made in a further manufacturing step, wherein this is in an at least partially closed position. By means of the disclosed production method it is achieved that a surface of the housing at least partially serves as a mold for forming a sealing section on the movable flap, so that a very close tolerance is achieved between the housing and the flap which can be moved relative thereto. Also according to US 5,304,336 the flap movable relative to the housing is butterfly-shaped. The housing is preferably one which is capable of accommodating a flap in the shape of a butterfly.

From EP 0 482 272 A1 and US 5,304,336 known manufacturing method for producing an air guide part by way of injection molding are associated with the disadvantage that can be produced according to this method moldings that may have poor functionality. This is essentially caused by insufficient adjustability and repeat accuracy of required gap widths in the journal bearings and in the gas passage bore of such manufactured devices. With the illustrated method is a targeted influencing the gap width to achieve a defined amount of air in the closed position of the flap on Maschineneinstellparameter during the molding, ie in the injection molding, not sufficiently possible. From one production cycle to the next production cycle, the required gap widths to achieve a defined amount of leakage air in the closed position of the flap are not sufficiently reproducible.

The accuracy or uniformity of such gaps in flaps may vary only in the range of a few microns. This is of considerable importance in the automotive sector, in which such air guide parts are exposed to a wider temperature range, such as temperatures of -40 ° C to + 120 ° C (engine operating temperature at the cylinder head area). By a close linkage of the temperature of the shaping tool and the cycle time of the injection molding process according to the above-indicated manufacturing method, the required accuracy can not be achieved by means of the cavity provided in the forming tool. This is particularly true when employed in the above-described solutions, semi-crystalline or amorphous thermoplastic high temperature plastics for the above temperature range for engine compartment applications. According to the manufacturing process, dating EP 0 482 272 A1 such as US 5,304,336 are known, can not respond flexibly enough to process fluctuations, such as property fluctuations in the molding compositions in the molding, ie the manufacturing process by means of injection molding. The fluctuations described unduly affect the quality of the devices obtained.

presentation the invention

According to the proposed Procedure will address the above weaknesses of the state of the art Technique known processes remedied, since the shape of the moldings, i.e. a flap part and a housing part of a throttle device, not done in a common cavity. The cavity within a two-component injection mold is divided into two separate cavities. The two separate cavities can by turntable or index plates or the like in two separate Be housed molds. The geometry of essential impression areas on the housing part during injection through the flap part during the second injection stage, can by changing the outer geometry the bordering tool parts in the second cavity opposite the first cavity for elastic deformation of the housing part (pre-molded part) in the second injection stage can be used. This is an additional the option of influencing the adjusting gap formation between the bearings and the housing part as well as the boundary of the flap part and the housing part to disposal. In the two separate cavities according to the invention proposed Process, become semi-crystalline and amorphous high-temperature thermoplastics with high melting temperatures optionally high crystallization degrees and high heat distortion as well as oil and Fuel resistance injected. The semicrystalline or amorphous high-temperature thermoplastics used have low friction coefficients and low wear rates among themselves. The gap geometries of the two-component injection molding process obtained injection molded part, its housing part from a first plastic material and its flap part of a second plastic material is made, lie before the introduction another, i. third material, outside a leak specification. To the introduction of the third additional Material and optionally after its partial removal the resulting gap geometries now within again the leak specification.

When third material to be used on an injection molded part to increase the Gap-tightness powdery Solid parts or pasty prepared materials in the two-component injection molded part introduced and can from this later partially or completely be removed again. The injection molded part taken from the injection mold has a relatively large Gap width on. The mentioned third material can either be on the throttle or on the Inner wall of the throttle body or directly into the gap between the throttle and the inner wall of the throttle body be introduced as an additive. The additive seals the Gap between the throttle and the throttle body largely but is so yielding or is at the first movement of the Throttle shears so sheared that a small gap width is formed, Nevertheless, no jamming between the throttle and the Throttle body feared must become. This makes it possible while the injection molding process the permissible Gap width to choose so that under consideration never completely avoidable Tolerances, one possible large gap width arises. This allows that before applying the additive the gap width S may scatter quite strong, causing the injection molding considerably is facilitated because the obtained gap width S by on or Application of the third material defined after injection molding and not immediately during the injection molding process beige leads needs to be. This also allows the use of such injection molded parts, its gap S without attaching an additive between the throttle edge and inner wall of the throttle body spraying in terms of tolerance to count to the committee are.

By Use of the invention proposed solution becomes the intrinsic disadvantage of clamping in the manufacturing process the flap in the housing avoided. The shrinkage in and after the plastic injection molding process is set so that the tightness outside the usual market density specification lies and by subsequent Introducing a third substance, i. of additional material in the Sealing gap changed so is that the tightness again standard market tightness specifications Fulfills. In particular, the shrinkage in the second injection molding process step, i. for the Throttle valve, chosen relatively large. this will achieved by keeping the mold temperature low and thereby a correspondingly rapid cooling of the plastic melt can be done. Furthermore, by enrichment of the second plastic material, which in the second injection molding process is used with fillers a small fiber part in the plastic material can be adjusted. Especially the proportion of granular, non-fibrous fillers in the second plastic material for the second injection molding step chosen relatively large. especially can the obtained plastic injection molded parts after the plastic injection molding process be tempered before the third material, i. the additive introduced becomes. The third material may be a solid lubricant act.

The annealing of Kunststoffspritzgießbauteile or the housing blank may be done after the first injection molding or after the second injection molding, but in any case before the third material introduced into the injection molding become.

drawing

Based In the drawings, the invention will be described below in more detail.

It shows:

1 the frequency distribution number of pieces gap width in previous production of throttle valve devices,

2 , Curve 1 the frequency distribution number of pieces / gap width during production according to the procedure according to the invention before application of an additive,
Curve 2 the frequency distribution number of pieces / gap width during production according to the solutions according to the invention after application of the additive,

3 a preform inserted in a second injection station and a second cavity for injecting a second plastic material,

4 and 5 the preform of the housing part of a second plastic material within the second cavity injected flap parts whose flap shaft parts in 4 are provided with an insert sleeve / slide bushing and the flap shaft parts according to 5 are molded directly into the pre-molded part,

6 Application surfaces on the preform, on which after forming the preform in a first injection station lubricant or lubricant is applied or rubbed or applied in film form, and

7 further possible application surfaces on the pre-molded part according to 6 ,

variants

The representation according to 1 is the frequency distribution number of pieces / slit width during manufacture of a throttle body according to known from the prior art injection molding.

From the illustration according to 1 shows that with S _1, the minimum gap between the edge of the throttle, the inner wall of a throttle body, the lower rejects limit. If the gap width S ₁ falls below, there is a jamming of the pivotally mounted throttle valve within the throttle body. Injection molding finished parts, which fall below the minimum gap width S ₁ , therefore, can not be used and represent expensive produced waste. With S ₂ , the maximum gap width between the edge of a pivotally received in the throttle body throttle valve and the inner wall of the throttle body is called. If the maximum gap width S _{2 is} exceeded, there is an excessively large gap between the edge of the pivotably arranged throttle flap and the inner wall of the throttle body, via which an internal combustion engine draws in too much false air, thus no longer ensuring perfect functioning of the throttle device.

All Spritzgießbauteile the gap width, which lie between the minimum gap width S ₁ and the maximum allowable gap width S ₂ , represent good parts, which could be used on an internal combustion engine, whether in the intake, be it in the exhaust system.

According to the diagram 2 are the curve 1 and the curve 2 refer to. The curve 1 represents the number distribution before introduction of the third material, ie the density determining additive before its introduction. The number distribution according to curve 1 is plotted over the gap width. The curve 2 represents the number of pieces distribution after introduction of the third material, ie the density determining additive. During curve 1 represents the number of preforms obtained, the gap width is predominantly greater than the maximum allowable gap S ₂ , shows curve 2 the number of preforms obtained, the gap width was chosen to be relatively large and S is at most the gap width S ₂ , after between the inner wall of the throttle body and the outer edge of the throttle, the third material, ie, the density-defining additive was introduced. From curve 2 It can be seen that the number of preforms which constitute good parts, ie which can be reused, could be substantially increased by using the method proposed according to the invention. By using the proposed method according to the invention in the allowable Toleranzmaß, ie in the range between the minimum allowable gap S ₁ and the maximum allowable gap S ₂ to be counted to the committee, since the maximum gap width S ₂ exceeding gap widths having preforms, so that overall a much higher productivity can be achieved by using the method proposed according to the invention in the production of plastic components produced by means of the two-component injection molding process.

This is achieved in that the shrinkage, especially in the second injection molding process step, ie when injecting the flap in the throttle body, is made large. This leaves reach through a cooled injection mold, which allows rapid cooling, ie solidification of the plastic melt. If fillers, such as, for example, granular non-fibrous materials, are added to the second plastic material used in the second injection molding step, the shrinkage process is additionally promoted by this process parameter. The third material, ie the seal defining additive, may be a solid lubricant such as molybdenum disulfide (trade name: Molykote) or other molybdenum compounds or graphite.

3 shows a pre-injection insert in a second injection station and a second cavity for injecting a second plastic material, from which the throttle valve is made.

Before a preform 41 in a second spray station 40 is used, according to the method proposed by the invention, an intermediate treatment of the pre-molded part 41 between the first injection stage, ie after removal from the first forming station and before insertion of the pre-molded part 41 in the in 4 illustrated second spray station 40 respectively. This may, for example, be a tempering process, but this is not absolutely necessary. After demolding a housing part 10 . 41 from the first cavity, ie after completion of the first injection stage, the pre-molded part 41 directly fed to a thermal intermediate treatment above the glass transition temperature of the first plastic material. This can be done, for example, within a heating cabinet. At the temperature level at which the intermediate treatment is carried out, induced stresses occurring in the thermoplastics during injection molding are reduced. This applies to both semi-crystalline thermoplastics and amorphous high-temperature thermoplastics. After a few minutes residence time of the pre-molded part 41 in the intermediate treatment sound through molecular orientations during the filling process of the first cavity or during rapid cooling of the pre-molded part 41 induced by delayed crystallization effects tensions and shrinkage effects in the thermoplastics to a negligible level.

Without the implementation of an intermediate treatment would be the molecular orientation or the rapid cooling of the pre-molded part 41 induced by delayed crystallization effects in semicrystalline thermoplastics stresses, the preform 41 live throughout its entire service life. Due to the thermal intermediate treatment is avoided that the induced voltages to a possibly over a longer period of operation of the throttle valve unit continuing back deformation of the pre-molded part 41 and thus lead to a change in the gap geometries. The change of the gap geometries due to back deformations of the housing 10 , ie the pre-molded part 41 without thermal intermediate treatment, lead in extreme cases to possible setting a relative to the pre-molded part 41 ie to the housing part 10 movable flap part 17 ,

The in 4 represented pre-molded part comprises the housing part 10 a throttle valve unit for performing the second injection stage, within the second injection station 40 becomes the preform 41 taken from the first cavity of the first spray station. After injection molding of the pre-molded part 41 from a first plastic material, the pre-molded part 41 in an injection molding by manually reacting, by pressing a preform 41 transporting turntable, an index plate or a handling system of the second spray station 40 be supplied. In the second spray station 40 is a second cavity 42 for the training of the preform 41 to be integrated flap part 17 intended. The geometry of essential impression areas on the pre-molded part 41 during back injection of the flap part 17 in the second spray station 40 , Can by changing the outer geometry of the bordering tool parts of the second cavity 42 , opposite the first cavity, for elastic deformation or prestressing of the pre-molded part 41 as part of the second injection stage within the second spray station 40 be used. This is a tool technical influencing possibility of a later gap formation between the sealing edge of the flap part 17 and the bearings in the preform 41 to disposal.

When using the proposed method, the sealing edge of the flap part 17 be designed so that the flap part 17 Non-contact in the injection molded part through the gas passage opening 13 plunges through. The sealing edge on the flap part 17 is in execution of a dipping designed flap part 17 in terms of tightness specification then considered to be sealing, if at the gap between the flap part 17 and the inner wall of the gas passage opening 13 Air mass flow of 2 kg / h to 6 kg / h is allowed, which depends on the diameter of the gas passage opening 13 in the pre-sprayed housing part 10 Alternatively, this can preferably be done with a curved flap surface in the pre-sprayed housing part 10 injected flap part 17 also as a non-penetrating flap part 17 molding, which within the gas passage opening 13 usually in an inclined position between 8 ° and 10 °, based on a vertical 90 ° position of the flap part 17 in the gas passage opening 13 reached its largely sealing position. Even with non-dipping flap parts 17 is in the "sealing position" of the im Pre-sprayed housing part 10 pivotable flap part 17 between the sealing edge and the inner wall of the gas passage opening 13 an air mass flow in the order of 2 kg / h to 6 kg / h allowed. Such a non-penetrating throttle valve is to be regarded as "leak-proof" in the sense of the leak-tightness specification, depending on the diameter dimensioning of the gas passage opening 13 in the pre-sprayed housing part 10 It is also possible to permit higher air mass flows than the above-stated 2 kg / h to 6 kg / h, with the throttle valve unit still being regarded as "leak-tight" even in the event of higher air mass flow rates passing through the sealing edge in the sense of the leakproofness specification.

The second spray station 40 as shown in 4 contains the second cavity 42 , which through the opposite end faces of a first mold insert 43 or a second mold insert 44 is defined. At the second cavity 42 limiting side of the first mold insert 43 is a contouring 47 educated; furthermore, it lies on that of the second cavity 42 assigning side of the first mold insert 43 the bleed 24 , 4 is removable, that by the contouring 47 of the first mold insert 43 formed on one side of the flap surface ribbing is formed. The ribbing and the contour of the flap surface are carried out according to the mechanical and fluidic requirements of the produced throttle valve unit. In addition to a curved trained flap surface of the flap part 17 This can also be trained plan.

The second cavity 42 is also from a first core part 45 or a second core part 46 limited. That in the second cavity 42 injected second plastic material flows around the opposite tips of the core parts 45 and 46 , This will be in the second cavity 42 Cavities of the first flap shaft part 19 or the second flap shaft part 20 shaped. The core parts 45 respectively. 46 are within the second spray station 40 of pods 48 enclosed, which can be designed to be pulled in the horizontal direction as well as in the vertical direction. To vary the geometry is below the first mold insert 43 a spacer ring 49 admitted.

The 4 and 5 In each case, the second cavity is removed, which is completely filled with the second plastic material, wherein in the embodiment according to 4 an insert sleeve is inserted in the pre-molded part while in the in 5 illustrated embodiment, the flap part is injected directly into the wall of the pre-molded part.

About the injection point 24 in the first mold insert 43 becomes the second plastic material 57 in the in the 4 and 5 no longer existing second cavity 42 injected, in the illustrated state already completely with the second plastic material 57 is filled. Corresponding to the contouring of the two mold inserts bounding the second cavity 43 respectively. 44 becomes a flap part 17 in the pre-molded part 41 formed. At this are made of the second plastic material 57 shaped flap shaft parts 19 respectively. 20 formed. Due to the movable at the second spray station 40 molded core parts 45 respectively. 46 are in the flap shaft parts 19 . 20 Cavities formed to avoid accumulation of material.

The flap shaft parts 19 respectively. 20 enforce the inner wall of the pre-molded part 41 , which the housing part 10 represents. The inner wall of the pre-molded part 41 is with reference numerals 53 characterized, the outer wall with reference numerals 54 , According to the shape of the now from the second plastic material 57 filled second cavity 42 be at the flap shaft parts 19 respectively. 20 opposite each other, the wall of the pre-molded part 41 forming, sealing surfaces generated. In the axial direction to the first sealing surface 55 then, can on the flap shaft parts 19 respectively. 20 before the second injection stage, sliding bushes 52 (See illustration according to. 4 ) in the openings 14 for the valve waves in the pre-molded part 41 be inserted or pressed. These are when injecting the second plastic material 57 over the injection point 24 from the second plastic material 57 filled and are thus fit on the first flap shaft part 19 or the second flap shaft part 20 added. The with reference numerals 52 designated Gleitbuchse is made of a material with friction and wear-reducing properties in the axial length of the respective flap shaft part 19 . 20 educated. As shown in 5 is the flap shaft part 20 directly into the wall of the pre-molded part 41 without interposing an insert sleeve as in 4 injected. This applies analogously to the first flap shaft part 19 ,

However, it is equally possible that in 5 on the drive side of the flap part 17 lying flap shaft part 20 , here without a bush 52 is shown, or 19 , with a corresponding slide bush 52 to provide. Out 4 goes the flap shaft part 19 protruding, which with a sliding bushing 52 is provided. The representations according to the 7 and 8th s ind contract surfaces on the finished component obtained, ie refer to the pre-molded part of a throttle valve unit on which applied after removal from the tool a lubricant / lubricant, rubbed or applied in foil form.

After the optional thermal intermediate treatment of the pre-molded part 41 , after its production within a first injection station and before the insertion of the pre-molded part 41 in the second spray station 40 , can be applied to impression surfaces 63 respectively. 64 for the second plastic material, which subsequently into one through the pre-molded part 41 limited second cavity 42 is injected, a material applied, so that the first plastic material of the pre-molded part 41 not directly with the second plastic material 57 , from which the flap part 17 including flap shaft part 19 and 20 in the second spray station 40 is made, comes in contact. Thus, using the method proposed by the invention with separate cavities also plastic materials can be used, which would otherwise adhere to each other. This also allows the use of identical first and second plastic materials to make a throttle body assembly.

About the introduction of a third material after the second injection molding process on molding surfaces 63 respectively. 64 ie between the sealing edge of the flap part 17 and the inner wall 53 the gas passage opening 13 , a possibly present there game, ie a gap width S, which is above the maximum tolerable gap width S ₂ , balanced. This measure may be a preform to be counted before the committee 41 be made back to a good part, which can be fed to a re-use. By injecting the third material, after the second injection molding process, which may be a pasty or a solid material, such as a molybdenum compound or graphite, the gap width is reduced, so that the tightness of the flap part 17 with respect to the gas passage opening 13 after the introduction of the third material after the second injection molding process again within the required diameter of the gas passage opening 13 dependent leak-tightness specification lies. According to a particularly advantageous aspect of the method proposed according to the invention, a higher gap width between the sealing edge of the flap part 17 and the inner wall 53 the gas passage opening 13 be achieved in that the injection mold, ie in the present case, the second spray station 40 during or after the injection / injection of the second plastic material 57 is cooled and a low mold temperature is maintained. This favors the shrinkage of the second plastic material 57 and allows a very rapid cooling of the melt of the second plastic material 57 in the second spray station 40 , On the other hand, a positive effect on the shrinkage behavior, ie, the setting of a relatively large gap width is possible by adding fillers in the second plastic material. By adding fillers to the second plastic material 57 its fiber content is reduced and reaches a greater proportion of granular materials, in turn, the shrinkage behavior of such a composite second plastic material 57 positively influenced.

From the illustration according to 7 shows that the third material after the second injection molding process on the second impression surfaces 64 can be applied, which through the inside of the openings 14 in the wall of the pre-molded part 41 for receiving the flap shaft parts 19 and 20 are formed. The application of the further third material after the second injection molding process, which the tightness of the pre-molded part 41 in the area of the openings 14 determined, can be done by applying, rubbing or off with a film material. In the illustration according to 7 can the preform after removal from the second spray station in the region of the insides of the openings 14 be coated with the other, third material after the second injection molding process.

The third material, ie the tightness between the sealing edge of the flap part 17 and the inner wall 53 the gas passage opening 13 defining additive, may be compliant or at the first movement of the flap part 17 relative to the gas passage opening 13 in the housing part 10 sheared off. This results in a smaller gap width S, with a clamping between the flap part 17 and the gas passage opening 13 is excluded. This can be ensured in a very simple manner that in all produced throttle body, the gap width S within the in 2 , compare curve there 2 , designated tolerances S ₁ minimum gap and S ₂ maximum gap is. As a result, the injection molding process considerably simplifies a greater scattering of the gap width obtained in the case of projection lengths 41 , which are produced by means of the two-component injection molding process can be achieved.

10

housing part

13

Gas passage opening

14

Opening for flap shaft

15

injection points for introducing the first plastic material

17

flap member

19

first flap shaft

20

second flap shaft

22

flow direction

24

injection point for second Plastic material

40

second injection station

41

Preform

42

second cavity for flap part 17

43

first mold insert

44

second mold insert

45

first Core part (can be pulled horizontally)

46

second Core part (can be pulled horizontally)

47

Contouring first mold insert 43

48

Sleeve for core parts (can be pulled horizontally or vertically)

49

spacer

52

bush

53

Inner wall of pre-molded part 41

54

Outer wall pre-molded part 41

55

sealing surface

57

second Plastic material

60

Two-component injection molded part from second injection station 40

61

flap gap Gas passage opening

62

gap geometry flaps stock

63

first bearing surface for third material

64

second application surface for third material

70

first bush

71

second bush

Claims (9)

Method for producing a throttle valve unit, a housing part ( 10 . 13 . 53 ) and a relative to this movable flap part ( 17 ) comprising, with the following method steps: a) the injection molding of the housing part ( 10 . 13 . 53 ) in a first cavity made of a first plastic material, b) the transfer of the pre-molded part obtained according to process step a) (US Pat. 41 ) of the housing part ( 10 . 13 . 53 ) in a spatially separated from the first cavity second cavity ( 42 ), c) the injection molding of the movable flap part ( 17 ) of a second plastic material ( 57 ) within the pre-molded part ( 41 ) of the housing part ( 10 . 13 . 53 ) in the second cavity ( 42 ), which during the injection molding of the second plastic material 57 is cooled and d) the introduction of a third material after the injection molding of the 2 , Plastic material ( 57 ), into the gap geometries ( 61 . 62 ) of an obtained two-component injection molded part ( 60 ), the gap geometries ( 61 . 62 ) prior to introduction of the third material outside the density specification and after introduction of the third material, optionally with partial removal of the third material, within the density specification. A method according to claim 1, characterized in that between the transfer according to the method step a) obtained pre-molded article ( 41 ) of the housing part ( 10 . 13 . 53 ) from the first cavity into the spatially separated second cavity ( 42 ) a thermal intermediate treatment of the pre-molded part ( 41 ) he follows. Method According to claim 2, characterized in that the thermal intermediate treatment takes place by a tempering process. A method according to claim 1, characterized in that in the gap geometries ( 61 . 62 ) of the two-component injection molded part ( 60 ) according to process step d) introduced third material is a solid lubricant. Method according to claim 1, characterized in that the second plastic material ( 57 ) Fillers are mixed with a small fibrous fraction and a large granular fraction. Method according to claim 4, characterized in that as a solid lubricant molybdenum compounds or graphite. Method according to claim 6, characterized in that as the third material molybdenum disulfide is introduced. Method according to claim 1, characterized in that the third material after the second injection molding according to process step c) is introduced. A method according to claim 1, characterized in that after the injection molding of the housing part ( 10 . 13 . 53 ) according to method step a) and before the injection molding of the movable flap part ( 17 ) of the second plastic material ( 57 ) within the pre-molded part ( 41 ) Bushings for the movable flap part ( 17 ) in the pre-molded part ( 41 ) are introduced.