EP1644174A2

EP1644174A2 - Method for producing a throttle valve unit in a two-component injection molding process

Info

Publication number: EP1644174A2
Application number: EP04738679A
Authority: EP
Inventors: Christian Lorenz; Wolfram Hasert; Johannes Meiwes; Wolf-Ingo Ratzel; Jochen Kaesser; Roland Schreiber
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2003-07-01
Filing date: 2004-06-15
Publication date: 2006-04-12
Also published as: BRPI0412129A; JP4436828B2; DE10329484A1; CN1816436A; WO2005002823A2; US20060138697A1; US7790083B2; WO2005002823A3; JP2006521939A

Abstract

The invention relates to a method for producing a throttle valve unit which comprises a housing part (10, 13, 53) and a valve element (17, 18, 23) that can be moved relative thereto. Said method comprises the following steps: injection-molding the housing part (10, 13, 53) into a first cavity consisting of a first synthetic material; transferring the preliminary injection-molded article (41) of the housing part (10, 13, 53) from the first cavity to a second cavity which is spatially decoupled therefrom; and injection-molding in said second cavity the movable valve element (17, 18, 23) consisting of a second synthetic material (57) inside the preliminary injection-molded article (41) of the housing part (10, 13, 53). Before the preliminary injection-molded article (41) is transferred to the second cavity (42), it is subjected to an intermediate treatment in order to influence the shrinkage behavior, thereby specifically adjusting the gap geometries between the parts (41; 17, 18, 23).

Description

Process for producing a throttle valve unit using the two-component injection molding process

Technical field

In the automotive sector, throttle valve units are increasingly being mass-produced as plastic injection molded components. Such throttle valve units are, for example, valve housings produced by means of the injection molding process, together with valves that are injected into the housing. The throttle valve units used in the automotive sector are exposed to temperatures between - 40 ° C and 120 ° C, so care must be taken to ensure that the functionality of the molded parts with regard to the gap widths achievable in the injection molding process must be guaranteed in this temperature range ,

PRIOR ART EP 0 482 272 AI relates to a flap unit. A flap device and a method for producing a movable flap in a housing which receives the movable flap are disclosed. The valve and the valve housing are manufactured in one and the same tool. In a first injection molding step the housing is manufactured, in a subsequent injection molding step the disk-shaped flap is molded into it. Sealing sections are formed on the flap which is movable relative to the housing and which cooperate in a sealing manner with housing regions of the flap housing. The flap is preferably one that is of a butterfly design and the flap housing is one that accommodates a butterfly-shaped flap. The disclosed manufacturing method enables a much more cost-effective manufacture of a flap device for the field of commercial vehicles. The position of the flap and its housing position are fixed to the transverse position to the air passage direction in this embodiment variant. US 5,304,336 also relates to a method for producing a nozzle. The device contains a movable part and a housing for receiving the movable part. The moving part and the housing are manufactured by means of the injection molding process through sequential manufacturing steps. The housing is preferably injection molded in a first method step, while the part which is movable relative to the housing is manufactured in a further manufacturing step, the part being in an at least partially closed position. The disclosed manufacturing method ensures that a surface of the housing at least partially serves as a shape for forming a sealing section on the movable flap, so that a very narrow token is achieved between the housing and the flap that is movable relative to the latter. According to US Pat. No. 5,304,336, the flap, which is movable relative to the housing, is formed in a butterfly shape. The housing is preferably one that receives a butterfly-shaped flap. The production processes known from EP 0 482 272 A1 and US Pat. No. 5,304,336 for manufacturing a ventilation guide part by means of the injection molding process have the disadvantage that molded parts can be produced according to these processes, which may have inadequate functionality. This is essentially caused by inadequate adjustability and repeatability of required gap widths in the shaft bearings and in devices manufactured in this way in the gas through-hole. With the methods shown, it is not possible to influence the gap width in a targeted manner in order to achieve a defined amount of air in the closed position of the flap by means of machine setting parameters in the shaping, ie in the injection molding process. From one production cycle to the next production cycle, the gap widths required to achieve a defined amount of leakage air in the closed position of the flap cannot be reproduced to a sufficient extent.

The accuracy or uniformity of such gaps in flaps may only vary within a few μm. This is of considerable importance in the automotive sector, in which such air duct parts are exposed to a larger temperature range from temperatures of - 40 ° C to 120 ° C (engine operating temperature at the cylinder head area). By closely linking the temperature of the molding tool and the cycle time of the injection molding process in accordance with the manufacturing processes shown above, the required accuracy cannot be achieved via the cavity provided in the molding tool. This applies in particular when partially crystalline or amorphous thermoplastic high-temperature plastics for the temperature range specified above are used for applications in the engine compartment in the processes described according to the above solutions. According to the manufacturing process that from EP 0 482 272 AI and US 5,304,336 are known, process fluctuations such as, for example, fluctuations in the properties of the molding compounds during molding, ie during the manufacturing process by means of the injection molding process, cannot be reacted to with sufficient flexibility. The fluctuations described have an inadmissible impact on the quality of the devices obtained.

Presentation of the invention

The solution proposed according to the invention remedies the above-mentioned weaknesses of the methods known from the prior art, since the shaping of the molded parts, i. the flap part and the housing part are not in a common cavity. According to the method proposed according to the invention, the cavities are divided into two cavities that are separate from one another in a two-component tool. The two cavities, which are separated from one another, can be accommodated in two separate molds by means of a turntable or index plates or similar tools. The geometry of essential impression areas on the housing part during back injection through the flap part during the second injection stage can be used for the elastic deformation of the housing part (pre-molded part) in the second injection stage by changing the outer geometry of the bordering tool parts in the second cavity compared to the first cavity. This provides an additional possibility of influencing the gap which forms between the bearing points and the housing part and the edges of the flap part and the housing part. Partially crystalline and amorphous high-temperature thermoplastics with high melting temperatures, optionally high degrees of crystallization and high heat resistance as well as oil and fuel resistance are injected into the two separate cavities according to the method proposed according to the invention. The semi-crystalline or amorphous high-temperature thermoplastics used have low coefficients of friction and low wear rates among themselves.

Furthermore, according to an embodiment variant of the proposed injection molding method according to the invention, after the housing part has been demolded from the first cavity in the first injection stage, it can be fed directly to an intermediate treatment above the glass transition temperature of the plastic injected in the first injection stage. The glass transition temperature represents the glass transition temperature above which the molecular movement of polymer chains in the plastic increases suddenly (transition from hard / brittle to tough-elastic / elastic break behavior). The intermediate treatment of the pre-sprayed housing part between the first injection stage and the second injection stage serves to reduce the later tendency of the housing part (pre-molded part) to warp during operation. After the preform has been removed from the cavity of the first injection stage, it can be exposed directly to an elevated temperature level, the temperature level being above the glass transition temperature of the plastic material used in the first injection stage. At the high temperature level during the intermediate treatment, within a dwell time of the pre-molded part, for example within a heating cabinet, the stresses induced by molecular orientations during the filling process of the cavities or during the rapid cooling-down process of the pre-molded part by delayed crystallization effects decrease to a negligible residual stress and deformation level. Without the intermediate treatment after completion of the first injection stage, the molecular orientations or the delayed crystallization effects would lead to re-deformations of the housing part injection-molded in the first injection stage, which would extend over months or years. This leads to a change in the gap dimension and thus to an impairment of the function over the operating time of a throttling dapper unit, to the point of possible jamming or jamming of the flap part, which is arranged movably within a gas passage opening of the housing part. Through the intermediate treatment of the pre-injected housing part - and thus before it is inserted into the second cavity within the second injection stage - the housing part is brought into a state of minimal internal stress and high dimensional reproducibility. The intermediate treatment also serves as a buffer step to keep the state of the pre-injected housing part constant with regard to the part temperature or the voltage state within the housing part before it is inserted into the second cavity within a second molding station of an injection mold or serially operated injection molds. In this way, possible production disruptions, which would lead to non-uniformities in the production process and thus to quality losses, preform waste or restart losses, can be bridged. Production faults can also be bridged in that the housing part remains in an oven until production faults have been remedied and production can continue. In addition to heat treatment of the pre-injected housing part (pre-molded part) in a heating cabinet, vibrations generated by mechanical or electromagnetic means can also be injected into the pre-injected housing part. In addition, the pre-sprayed housing part can be exposed to black infrared radiation in order to reduce the stresses induced by a polymer chain orientation during the filling process of the cavities or by delayed crystallization effects to a residual voltage level that is not critical for the subsequent process. The intermediate, Generally speaking, the treatment step to which the pre-molded part obtained from the first injection station is subjected can be characterized by light and heat treatment of the pre-sprayed housing part (pre-molded part). In a further embodiment variant of the manufacturing method proposed according to the invention for a throttling dapper unit, after the intermediate treatment after the first injection stage and before inserting the pre-molded part into the second cavity of a second injection station, the subsequent mold surfaces for the second injected plastic material for molding the flap part into the pre-molded part additional material is applied or rubbed. This primarily serves as a lubricant and as a spacer layer, which can also be applied in the form of a film, for example, and which can later be easily or partially removed, for example by thermal influence.

Bushings made from a third material can also be used to further reduce frictional resistance or wear of the bearing points between the housing part and the flap part. The sliding or bearing bushes can either be inserted into the pre-molded housing part with an anti-twist device so that the flap shaft parts molded onto the preferably arched flap part can twist in them, or they can be inserted into the pre-sprayed housing part (pre-molded part) are that the bushings are able to rotate relative to the pre-injected housing part, the flap shaft parts of the preferably arched flap part being rotatably injected into the sliding or bearing bushes inserted into the wall of the pre-injected housing part. Both design variants are possible in accordance with the method proposed according to the invention. The bearing bushes are preferably made from a low-wear, metallic or non-metallic bearing material.

With the method proposed according to the invention for producing a throttling dapper unit, comprising a housing part and a flap part that can be moved relative to it, after the injection molding of the housing part in a first cavity made of a first plastic material, the subsequent transfer of the molded part of the housing part obtained into one of the first Cavity spatially separated second cavity and the injection molding of the movable flap part from a second plastic material within the pre-molded part of the housing part in the second cavity, a third material can be introduced into the gap geometries of the two-component injection molded part obtained in this way. If the gap geometries are within the two-component pre-molded part which is provided with bushings before the introduction of the third material outside a tightness specification, then after the introduction of the third Material and possibly its partial removal achieved that the said gap geometries are now within the tightness specification. As a third material in accordance with this embodiment variant of the method proposed according to the invention, powdery solid parts or pasty materials can be introduced into the two-component injection molded part to increase the gap tightness and later partially removed again.

If the gap geometries of a two-component injection molded part, whose housing part is made of a first plastic material and whose flap part is made of a second plastic material, and in which bushings are made of a third material, are outside a tightness specification before the introduction of a fourth material the introduction of the fourth material and, if necessary, the partial removal thereof, means that the said gap geometries are now within the tightness specification. According to this embodiment variant of the method proposed according to the invention to increase the gap tightness, powdery solid parts or pasty materials are introduced as fourth material into the two-component pre-molded part with bushings and later partially removed again.

drawing

The invention is described in more detail below with reference to the drawings.

It shows:

FIG. 1 shows a pre-molded housing part made of a first plastic material,

FIG. 2 shows a view of a flap part from the inflow direction with a curved flap surface,

FIG. 3 shows a view of the flap part from the rear with a ribbed flap surface,

FIG. 4 shows a pre-molded part inserted into a second injection station and a second cavity for injecting a second plastic material, FIGS. 5.1, 5.2 flap parts injected into the pre-molded part of the housing part from a second plastic material within the second cavity, the flap shaft parts in FIG. 5.1 being provided with an insert sleeve / sliding bush and the flap shaft parts according to FIG. 5.2 being directly molded into the pre-molded part,

6 shows the housing part obtained in separate cavities after passing through a first injection station and a second injection station, with a movable flap part injected into the pre-molded part of the housing part,

FIGS. 7, 8 application areas on the pre-molded part, to which lubricant or lubricant is applied or rubbed in or applied in foil form after the pre-molded part has been molded,

FIG. 9 bearing bushes inserted into the pre-molded part after removal from the first injection station and

Figure 10 is a bottom view of the flap part injection-molded from a second plastic material with insert sleeves / sliding bushes.

Design variants Figure 1 shows a pre-molded housing part made of a first plastic material.

A housing part 10 of a throttling dapper unit, which is used in the intake tract of an internal combustion engine, is injection-molded as an injection-molded component from a first plastic material. The first plastic material can be both semi-crystalline thermoplastics and amorphous high-temperature thermoplastics with high melting temperatures and possibly high degrees of crystallization as well as excellent heat resistance, as well as oil and fuel resistance. The amorphous high-temperature thermoplastics that can be used have a very high glass temperature which is at least 30 K above the continuous use temperature of the throttling dapper unit. The materials mentioned also have low coefficients of friction and low wear rates. The housing part 10 comprises a flange 11 on which flange fasteners 12 are provided in accordance with the available installation space. The housing part 10 delimits a gas passage opening 13, which has a wall thickness 16 is formed. Opposing openings 14 are provided in the wall of the gas passage opening 13 for receiving a flap part 17 to be molded in a further process step. The housing part 10 is manufactured as a pre-molded part in a first injection station. Injection points via which the first plastic material is introduced into the first injection station are indicated with reference number 15. Although only two injection points 15 are shown in FIG. 1, several, for example up to 8 injection points 15 can be provided, via which the first plastic material is introduced into the first cavity. The illustration according to FIG. 2 shows a view of a flap part, which is shown from the perspective of the direction of the inflow and has a curved flap surface.

The flap part 17 shown in Figure 2 has an approximately convex flap surface 18, on which a first flap shaft part 19 and a second flap shaft part 20 are molded. The flap surface 18 is provided with a sealing edge 23. The flap part 17 with molded first flap shaft part 19 and molded second flap shaft part 20 can be made from a second plastic material, which can also be a partially crystalline thermoplastic or amorphous high-temperature thermoplastic with high melting temperatures and possibly high degrees of crystallization. The second plastic material also has a high heat resistance, as well as oil and fuel resistance, and is also distinguished from the material of the pre-molded part 41 which represents the housing part 10 by a low coefficient of friction and a low wear rate. Taking into account process engineering parameters, the flap part 17 can also be made from the same plastic material as the pre-molded part 41 produced in the first cavity.

The second plastic material injected into the pre-molded housing part (pre-molded part), from which the preferably arched flap part 17 is formed, can either be a partially crystalline thermoplastic or amorphous high-temperature thermoplastics with a lower melting temperature compared to the melting temperature of the act first plastic material of the pre-injected housing part, or it can be used as a second plastic material, a semi-crystalline thermoplastic or amorphous high-temperature thermoplastic, which has a higher melting temperature compared to the melting temperature of the first plastic material of the pre-injected housing part, taking into account procedural conditions. 3 shows a view of the flap part according to FIG. 2 from the rear thereof, with one of the ribs on the flap rear facing away from the upstream side.

The flap part 17 according to the perspective view according to FIG. 3 is provided with ribbing 21 on its rear side. The ribbing 21 extends approximately in a star shape on the rear side of the flap surface 18 from an injection point 24, via which the second plastic material is injected into a second cavity of a second injection station. Starting from the flap surface 18 of the flap 17, the first flap shaft part 19 and the elongated second flap shaft part 20 extend on the drive side of the flap part 17. The illustration in FIG. 3 shows the rear side of the sealing edge 23 surrounding the flap surface 18. For reasons of the required mechanical strength, stiffening ribs can also be realized in the circumferential direction (for example in an elliptical or rounded shape). The illustration according to FIG. 4 shows a pre-molded part inserted into a second injection station and a second cavity for injecting a second plastic material via an injection point 24 for the flap part.

The second injection station 40 as shown in FIG. 4 contains a pre-molded part 41, which is designed as a housing part 10 of a throttling dapping unit. In order to carry out the second injection stage within the second injection station 40, the pre-molded part 41 is removed from a first cavity of a first injection station. After the injection molding of the preform 41 from a first plastic material, the preform 41 can be supplied to the second injection station 40 in an injection molding device by manual repositioning, by actuating a turntable transporting the preform 41, an index plate or a handling system. A second cavity 42 is provided in the second injection station 40 to form the flap part 17 to be integrated into the pre-molded part 41. The geometry of essential impression areas on the pre-molded part 41 during the back injection of the flap part 17 in the second injection station 40 can be changed by changing the outer geometry of the bordering tool parts of the second cavity 42 with respect to the first cavity for elastic deformation or pre-tensioning of the pre-molded part 41 within the scope of the second injection stage second spray station 40 can be used. This provides a tool-technical possibility of influencing a later formation of a gap between the sealing edge 23 of the flap part 17 and the bearing points in the pre-molded part 41.

On the one hand, using the method proposed according to the invention, the sealing edge 23 of the flap part 17 can be designed such that the flap part 17 is non-contact in the Injection molded part is immersed through the gas passage opening 13 in the pre-injected housing part 10 (pre-molded part). The sealing edge 23 on the flap part 17 is to be regarded as a seal with regard to the tightness specifications when a flap part 17 is designed so that a mass flow of 2 to 6 kg / h is permitted at the gap between the flap part 17 and the inner wall of the gas passage opening 13, whichever according to the diameter of the gas passage opening 13 in the pre-injected housing part 10 is to be regarded as "tight" in the sense of the tightness specification. Alternatively, the flap part 17, which is preferably injected into the pre-injected housing part with a curved flap surface, can also be formed as a non-penetrating flap part 17, which is inside 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, its largely sealing position is reached, even in the case of non-penetrating flap parts 17, “D In the "inoperative position" of the flap part 17, which can be pivoted in the pre-sprayed housing part 10, between the sealing edge 23 and the inner wall of the gas passage opening 13, an air mass flow in the order of magnitude between 2 kg / h and 6 kg / h is permitted. Such a non-penetrating throttle valve is to be regarded as "tight" in the sense of the tightness specification. Depending on the diameter dimensioning of the gas passage opening 13 in the pre-sprayed housing part 10, air mass flows higher than the above-mentioned 2 kg / h to 6 kg / h can also be achieved. can be left, the throttle valve unit even with the occurring higher air mass flows passing the sealing edge 23 in the sense of the tightness specification to be regarded as "tight".

The second injection station 40 as shown in FIG. 4 contains the second cavity 42, which is defined by the mutually opposite end faces of a first mold insert 43 and a second mold insert 44. A contouring 47 is formed on the side of the first mold insert 43 which delimits the second cavity 42; Furthermore, the gate 24 is on the side of the first mold insert 43 facing the second cavity 42. FIG. 4 shows that the contouring 47 of the first mold insert 43 forms the ribbing 21 formed on the rear side of the flap surface 18. The ribbing 21 and the contour of the flap surface are designed in accordance with the mechanical and fluidic requirements for the throttle dapper unit to be produced. In addition to a curved flap surface 18 of the flap part 17, this can also be made flat.

The second cavity 42 is also delimited by a first core part 45 or a second core part 46. The second plastic material injected into the second cavity 42 flows around the opposite tips of the core parts 45 and 46. As a result 42 cavities of the first valve shaft part 19 and the second valve shaft part 20 are formed in the second cavity. The core parts 45 and 46 are enclosed within the second injection station 40 by sleeves 48, which can be designed to be pullable in the horizontal direction as well as in the vertical direction. To vary the geometry, a spacer ring 49 is embedded below the first mold insert 43.

The pre-molded part 41 inserted into the second injection station 40 in FIG. 4 has an inner wall designated by reference numeral 53 and is designed with a wall thickness 16. The outer wall of the preform 41 is identified by reference numeral 54.

Before the pre-molded part 41 is inserted into the second injection station 40, intermediate treatment of the pre-molded part 41 between the first injection stage, ie after demolding from the first molding station and before inserting the pre-molded part 41 into the second one shown in FIG Spray station 40 take place. After the housing part 10, 41 has been removed from the mold from the first cavity, that is to say after the end of the first injection stage, the pre-molded part 41 is immediately subjected to an intermediate thermal treatment above the glass transition temperature of the first plastic material. This can be done, for example, inside a heating cabinet. At the temperature level at which the intermediate treatment is carried out, induced stresses that occur in the thermoplastics during injection molding subside. This applies to both semi-crystalline thermoplastics and amorphous high-temperature thermoplastics. After a few minutes of residence of the preform 41 in the intermediate treatment, stresses and shrinkage effects in the thermoplastics induced by molecular orientations during the filling process of the first cavity or during rapid cooling of the preform 41 decrease to a negligible residual level. Without carrying out an intermediate treatment, the stresses induced by molecular orientations or during rapid cooling of the preform 41 by delayed crystallization effects in partially crystalline thermoplastics would be inherent in the preform 41 during its subsequent operating time. Due to the thermal intermediate treatment, it is avoided that the induced voltages lead to a re-deformation of the pre-molded part 41, which may persist over a longer operating time of the throttling dapper unit, and thus to a change in the gap geometries. In extreme cases, the change in the gap geometries as a result of back-deformation of the housing 10, ie the pre-molded part 41, without thermal intermediate treatment leads to possible fixing of a flap part 17 that is movable relative to the pre-molded part 41, ie to the housing part 10. Instead of the thermal intermediate treatment described above, light and heat energy can be coupled into the pre-molded part 41 in the broadest sense. For example, an intermediate treatment can be carried out in such a way that black infrared radiation is injected into the pre-injected housing part 10; in addition, it is also entirely possible to couple vibrations - be they generated electromagnetically or mechanically - into the pre-injected housing part 10. Irradiation of vibrational energy into the pre-molded part 41 for reducing the voltage within the second injection station 40 is also possible. As a result of the intermediate treatment preceding the second injection stage, ie the second injection station 40, the pre-molded part 41 is brought into a state of minimal internal stress and high dimensional reproducibility before insertion into the second cavity 42 of the second injection station 40. The intermediate treatment following the first injection stage also serves as a buffer step for keeping the state constant with regard to the part temperature of the pre-molded part 41. The pre-molded part 41 subjected to an intermediate treatment has a temperature approximately at the same temperature level as after the end of the first injection stage within the first injection station , In this way, possible manufacturing disruptions, which lead to non-uniformities in the production process and thus to a loss in quality, and a rejection of pre-molded parts 41 or restarting losses due to intermediate storage of the pre-molded parts of the housing parts 10 at high temperatures can be largely prevented.

In a further embodiment variant of the method proposed according to the invention, after the intermediate treatment of the preform 41 between the first injection station and the insertion of the preform 41 into the second injection station 40, a further, third substance can be applied or rubbed onto later impression surfaces of the second plastic material in the preform. The application of a further, third substance prevents direct contact of the first plastic material of the preform 41 with the second plastic material, from which the flap part 17 is injection molded in the second injection stage 40 in the second injection station 40. This also makes it possible to use plastic materials that would otherwise adhere to one another and whose use would otherwise not make sense. Adhesion of the first plastic material to the second plastic material is prevented by introducing or rubbing in a further, third material. By introducing or rubbing in the further, third material, identical first and second plastic materials can also be used. With this further material, lubricants or lubricants, which are introduced as a solid or as pasty materials, can preferably be used. These reduce the frictional forces and consequently cause frictional wear between the parts in contact with one another, ie the inside of the gas passage opening 13 and the sealing edge 23 of the flap surface 18 and the shaft bearings. Furthermore, the further, third material applied to the impression surfaces can act as a spacer layer. It can be applied both by rubbing in and in foil form and can be easily or partially removed later, for example due to thermal influence. The further, third material can thus serve to form an additional, very precisely adjustable gap dimension, which cannot yet be obtained in the second injection station 40 in the course of the injection molding process of the second plastic material.

FIGS. 5.1 and 5.2 show the second cavity, which is completely filled with the second plastic material, an insert sleeve being inserted into the pre-molded part in the embodiment variant according to FIG. 5.1, and in the embodiment variant shown in FIG. 5.2 the flap part is directly in the Wall of the pre-molded part injected.

Via the injection point 24 in the first mold insert 43, the second plastic material 57 is injected into the second cavity 42, which is no longer present in FIGS. 5.1 and 5.2 and is already completely filled with the second plastic material 57 in this state. According to the contouring of the two mold inserts 43 and 44 delimiting the second cavity 42, a flap part 17 is molded into the pre-molded part 41. Flap shaft parts 19 and 20 formed from the second plastic material 57 are molded onto this. By means of the core parts 45 and 46, which are movably formed on the second injection station 40, hollow parts 19 and 20 are formed in the flaps (see illustration according to FIGS. 1 and 3) in order to avoid accumulation of substances.

The flap shaft parts 19 and 20 penetrate the inner wall of the pre-molded part 41, which represents the housing part 10. The inner wall of the pre-molded part 41 is identified by reference numeral 53, the outer wall thereof by reference numeral 54. Corresponding to the shape of the facing boundary surfaces of the first mold insert 43 and the second mold insert 44, which now form the second cavity 42 filled with the second plastic material 57, the Flap shaft parts 19 and 20 lying opposite one another, depicting the wall of the preform 41, generating light areas. Adjoining the first sealing surface 55 in the axial direction, slide bushes 52 (see illustration according to FIG. 5.1) can be inserted or pressed into the openings 14 for the valve shafts in the pre-molded part 51 on the flap shaft parts 19 and 20 before the second injection stage become. When the second plastic material 57 is injected, they are injected from the second plastic material via the injection point 24. filled in material and are thus fit on the first valve shaft part 19 and the second valve shaft part 20 received. The slide bush identified by reference numeral 52 is made of a third material with friction and wear-reducing properties in the axial length of the respective flap shaft part 19, 20. According to the illustration in FIG. 5.2, the flap shaft part 20 is injected directly into the wall of the preform 41 without the interposition of an insert sleeve, as in FIG. 5.1. This applies analogously to the first folding shaft part 19.

However, it is equally possible to provide the flap shaft part 20, which is shown here without slide bush 52, or 19 with a corresponding slide bush in FIG. 5.2 on the drive side of flap part 17. The flap shaft part 19 is shown in FIG. 5.1, which is provided with a sliding bush 52.

FIG. 6 shows the molded part obtained in separate first and second cavities after passing through a first and second injection stage with the flap part 17 movably injected into the housing part 10 of an air guiding device. It can be seen from FIG. 6 that the molded part representing the housing part 10 receives the flap part 17. A flap gap 61 is established between the sealing border 23 of the flap surface 18 made of the second plastic material 57 and the inner wall 53 of the gas passage opening 13 due to the shrinkage of the materials. Furthermore, valve gaps 62 occur in the area of the valve bearings. The openings (not designated in FIG. 6) for receiving the flap shaft parts 19 and 20 are penetrated by them, the second flap shaft part 20 being of elongated axial length. A two-component injection molded part 60 according to the illustration in FIG. 6 comprises in its foot region the flange 11, which can be connected to other intake system components, for example on an internal combustion engine, in accordance with the available installation space and the hole pattern.

In the illustration according to FIG. 6, the flap part 17 rotated in the closed position closes the gas passage opening 13, forming a flap gap 61 between the sealing border 23 of the flap surface 18 of the flap part 17 and the inner wall 53 of the gas passage opening 13 of the housing part 10. During the pre-molded part 41, which forms the housing part 10 of the throttling dapper unit is made of a first plastic material, is manufactured within a first injection stage in a first injection station, the flap part 17, which is injection molded in the second cavity 42 of the second injection station 40, is made of a second plastic material 57. The depictions according to FIGS. 7 and 8 show application areas on the pre-molded part of a housing of a throttling dapper unit, to which a lubricant / lubricant is applied, rubbed in or applied in foil form after the pre-molded part has been molded.

After the intermediate treatment of the preform 41 after its production within a first injection station and before the insertion of the preform 41 in the second injection station 40, subsequent molding surfaces 63 and 64, respectively, are used for the second plastic material 57, which is subsequently divided into a second one delimited by the preform 41 Cavity 42 is injected, another, third material applied so that the first plastic material of the pre-molded part 41 does not come into direct contact with the second plastic material 57, from which the flap part 17 together with flap shaft parts 19 and '20 in the second injection station 42 is made comes. Thus, using the method according to the invention with separate cavities, plastic materials that would otherwise adhere to one another can also be used.

This also makes it possible to use identical first and second plastic materials to produce a throttling dapping unit. The further, third material with which the first impression surface 63 or the second impression surface 64 of the preform 41 is treated allows the use of plastic materials that would otherwise adhere to one another. The further material applied to the first impression surface 63 or the second impression surface 64 is preferably a lubricant / lubricant, which is preferably used as a solid powder or as a paste-like compound or as a film. This material serves to reduce frictional forces and the consequent frictional wear between the parts of the pre-molded part 41 which are in sliding contact with one another, ie its inner wall 53 and the sealing edge 23 of the flap part 17 made of the second plastic material 57. In this connection it should be emphasized that the flap part 17 the throttling dapping unit can be configured both as a through-flap part and as a non-through-flap part 17. While a flap part 17 that is designed to be immersed is accommodated in the gas passage opening 13 without a stop, a flap part 17 that is configured to be non-immersed interacts with a stop formed on the inner wall 53 of the gas passage opening 13. In both design variants of the flap part 17, that is to say through and not through, there are gaps over the sealing edge 23 of the flap part 17 with the inner wall 53 of the gas passage opening 13, which have an air mass flow of between 2 kg / h and 6 kg / h are flowed through, these air mass flows depending on the dimensioning of the gas passage opening 13 in the pre-injected housing are part 10. Depending on the diameter dimensioning of the gas passage opening 13 in the pre-sprayed housing part 10, larger air mass flows over the sealing edge 13 of a flap part 17 which is designed to be immersed or not, in which the throttle plug unit is to be regarded as “tight” in the sense of the tightness specification the further, third material applied to the first impression surface 63 or the second impression surface 64 act as a spacer layer. This further, third material in its function as a spacer layer can be applied as a film to the annularly configured first mold surface 63. This offers the advantage that the spacer layer can later be easily or partially removed, for example by thermal influence. The application of the further, third material to the first contact surface 63 of the preform 41 allows the formation of a very precisely adjustable gap dimension 6 2 to (compare illustration according to FIG. 6).

According to FIG. 8, the further, third material can also be applied to the second impression surfaces 64, which are formed through the inside of the openings 14 in the wall of the preform 41 for receiving the flaps shaft parts 19 and 20. After production of the pre-molded part 41 in the first injection station and its intermediate treatment and before inserting the pre-molded part 41 in the second injection station 40, the openings 14 for receiving the flap shaft parts 19 and 20 can be made analogously to the first contact surface 63 of the pre-molded part 41 as shown in FIG 7 are coated with the further, third material. The further, third material can be applied in the area of the openings by applying, rubbing in or lining with a film material. In the illustration according to FIG. 8, the preform 41 is coated with the further, third material after removal from the first molding station in the region of the inner sides of the openings 14.

In a further preferred embodiment variant of the manufacturing method of a throttle valve unit on which the invention is based, after the thermal intermediate treatment before inserting the pre-molded part 41 obtained in the first injection stage 42 into the second cavity 42, prefabricated bearing bushes are formed with a corresponding pre-tension in the wall of the pre-molded part 41 Openings 14 inserted or pressed in (see illustration according to FIG. 9).

FIG. 9 shows that the first sliding bushing 70 and the second sliding bushing 71 can be configured as sleeve-shaped inserts which are pre-stressed into the opening of the walls of the housing 10 delimiting the gas passage opening 13. The pre-molded part 41, which forms the housing part 10 of a throttling dapping unit, is injection molded from the first plastic material, the gas passage opening 13 of which is formed by a plastic material tube formed in a wall thickness 16. The flange 11, which is provided with differently positioned flange openings 12 in accordance with the hole pattern, is located in the foot region of the pre-molded part 41. Slide bushings 70 and 71 are inserted or pressed into the openings 14 in the wall of the gas passage opening 13 (see also illustration according to FIG. 10). A pressing of the sliding bushes 70, 71 or the sliding bush 52 as shown in FIG. 5.1 into the wall of the pre-sprayed housing part 10 delimiting the gas passage opening 13 causes the sliding bushes 70 and 71 to be prevented from rotating. In this case, the flap shaft parts 19 and 20 are manufactured such that they can be rotated relative to the slide bushings 70, 71 inserted in the pre-injection-molded housing part 10 in an inhibited manner. Alternatively, the sliding bushes 70, 71 can be rotatably injected into the wall of the pre-injection-molded housing part 10, in which case the flap shaft parts 19 and 20 of the flap part 17 are injection molded into the sliding bushes 70 and 71 in a rotationally fixed manner. Figure 10 shows a sectional bottom view of the flap part injection molded from the second plastic material with pressed-in sliding bushes.

10 shows that on the underside of the flap surface 18 of the flap part 17 a rib 21, for example star-shaped, extends from the gate 24. The cavities in the first flap shaft part 19 or in the second flap shaft part 20 can be seen by pulling the horizontally pullable first core parts or second core parts 45 or 46. On the first flap shaft part 19 or on the second flap shaft part 20, the first sliding bushing 70 or the second sliding bushing 71 can be seen, which, before the flap part 17 is molded from the second plastic material 57 in the second cavity 42 of the second injection station 40 into the openings 14 in FIG Wall of the gas passage opening 13 were pressed or inserted.

The gap dimension 61 shown in FIG. 6 is established between the sealing border 23 of the flap surface 18 and the inside 53 of the gas passage opening 13. To the

Slide bushings 70 and 71 are set according to the selected tolerance gap dimensions 62 at the two opposite bearing points of the flap part 17. With Reference numeral 54 designates the outer wall of the housing 10, which is formed in the material thickness 16.

The slide bushing designated by reference numeral 52 can be inserted into the wall of the pre-molded part 41 in such a way that the slide bushings 51, 52 are accommodated in the latter in an inhibited manner. The shaft parts 19 and 20 of the flap part 17, which are molded in a rotationally fixed manner, enable a rotary movement of the flap part 17 formed with a curved flap surface 18; on the other hand, the sliding bushing 52 can also be designed such that the flap shaft parts 19 and 20 are molded in a rotationally fixed manner in the sliding bushing 52 according to the illustration in FIG. 5.1 of the flap shaft part 17. In this case, the sliding bushing 52 is let into the wall of the pre-molded part 41 in such a way that the sliding bushing 52 can still be rotated relative to the pre-sprayed housing part 10 (pre-molded part 41). Although only one half of the flap part 17 is shown in FIG. 5.1, the flap shaft part 19 of which is enclosed by a sliding bush 52, the flap shaft part 17 can be accommodated on both sides by insert sleeves in the pre-molded part 41. Similarly, as indicated in FIG. 5.2, both flap shaft parts 19 and 20 can be accommodated in the pre-molded part 41 directly without the interposition of sliding bushes 52. In a further advantageous embodiment of the method proposed according to the invention, in order to influence or make it easier to adjust the gap geometries 61 or 62 between the inner wall 53 of the preform 41 and the sealing edge 23 of the flap part 17, the injection points 24 or 15, which represent the injection points of the plastic materials , are specifically positioned on the cavities for the components 10, 41 and 17, 51 to be molded. The plastic melts for filling the cavities enter the first injection station and the second injection station 40 via the injection points 15 and 24, respectively, which represent the filling points of the first cavity and the second cavity. Depending on the geometrical position of the injection points 15, 24, the orientation of the chain molecules in the plastic materials as well as their reinforcement and fillers, the shrinkage behavior of the manufactured pre-molded part 41 and the flap part 17 can be influenced by the flow orientation of the plastic melts depending on the geometric position of the injection points 15, 24 in such a way that During the cooling phase that follows the injection molding process, the throttle valve unit, ie the two-component pre-molded part 60, procure the desired gap dimensions 61, 62 between the storage locations of the flap part 17, be it through or non-through, and the sliding bushes 52, 70, 71 , The required gap of a few μm between the sealing edge 23 and the inner wall 53 of the gas passage opening 13 is formed. The gap dimension between the inner wall 53 of the gas passage opening 13 of the preform 41 and the sealing edge 23 of the Flap part 17 remains largely constant during operation of the throttle dapper unit produced according to the invention, even with extreme temperature changes, and does not experience any changes in the air mass flow, which is obtained in the sealing position of flap part 17 - be it through or non-through - and the inner wall 53 of the gas passage opening 13 , sets, negatively influenced.

With the plastic materials currently used for the pre-molded part 41, which represents the housing part 10 or the flap part 17, these plastic materials can have high fiber reinforcement proportions. Due to the high proportion of fiber reinforcement, which brings about reduced geometric changes in the direction of the fibers when the polymer chains are reoriented, as well as reduced expansion coefficients in the direction of the fibers, in order to achieve a high degree of geometric stability of the injection molded part 60 with regard to the gap dimensions 61, 62, the pre-molded part 41 can have several punctiform injection points 15 on the circumference of the wall , which delimits the gas passage opening 13 near the flap plane and the flap part 17 itself are injection molded centrally in the middle. In the region of the flap shaft parts 19, 20 injected into the pre-molded part 41, the fiber profiles in the flap shaft parts 19 and 20 are oriented parallel to the axis of the flap part 17, whereby a shrinkage behavior is set, which in the pre-molded part 41 and in the flap part molded into it leads to similar shrinkage.

With the two-component injection molding method proposed according to the invention in cavities that are spatially separated from one another in two sequentially passing injection stations, throttle valve units can be produced with high precision by means of the method proposed according to the invention, in which post-processing operations are negligible, the reject rates on pre-molded parts 41 are drastically reduced and that adjusting gap geometries 61 and 62 remain guaranteed over the life of the air guide device due to the early reduction of deformations causing internal stresses. According to a further, finally listed embodiment variant of the method proposed according to the invention for producing a throttle dapper unit, in the case of impermissibly large gap dimensions 61, 62, a further, fourth material can be inserted between the sealing edge 23 of the flap part 13 and the inner wall 53 of the gas passage opening 13 and between the insertion sleeves or sliding bushing columns Two-component injection molded part 60 are introduced. With this further, fourth material, a sliding layer can be formed both between the flap parts 17 that can be moved relative to one another and the inner wall 53 of the gas passage opening 13, and between the flap shaft parts 19 and 20 and the sliding bushes 52, 70 and 71, and between the sliding bush sen 52, 70, 71 and the openings in the pre-molded housing part 10 are built. If this fourth introduced material is completely or partially removed again, for example the gap dimensions 61, 62 previously lying outside the tightness specification in the two-component pre-molded part 60 can again be within the tightness specification of the throttle valve unit. Analogous to the above, the respective tightness specification for throttle valve units is in each case dependent on the diameter of the gas passage opening 13 in the pre-sprayed housing part 10, which represents the pre-molded part 41. A throttle valve unit that fulfills the tightness specification is to be regarded as “tight” in the sense of the tightness specification if the air mass flow that occurs over the gap between the sealing edge 23 and the inner wall 53 of the pre-sprayed housing part 10 or at the gap geometries 61, 62 is within a range of 2 kg / h to 6 kg / h.

With regard to the list of signs

Housing part flange flange fastenings gas passage opening for flap shaft injection points for introducing the first plastic material wall thickness flap part flap surface first flap shaft second flap shaft ribbing inflow direction sealing edge gating point for 2nd plastic material second injection station pre-molded part second cavity for flap part 17 first mold insert second mold insert first core part (horizontally pullable) second core part horizontally pullable) Contouring first mold insert Sleeve for core parts (horizontally or vertically pullable) Spacer ring

Slide bushing inner wall of pre-molded part 41 outer wall of pre-molded part 41 sealing surface of second plastic material

Two-component injection molded part from a second injection station 40 flap gap gas passage opening Gap geometry flap bearing first contact surface release agent (layer) second application surface release agent (layer)

first slide bush second slide bush

Claims

claims

1. A method for producing a throttle dapper unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) c) spatially separated from the first cavity and injection molding of the movable flap part (17, 18, 23) made of a second plastic material (57) within the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42).

2. Method for producing a throttle valve unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) injection molding the movable flap part (17, 18, 23) made of a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and di) the demolding of the housing part (10, 13 , 53) at very high temperatures and maintaining this temperature for stress relaxation and to enable post-crystallization processes.

3. A method for producing a throttle dapper unit, comprising a housing part (10, 13 53) and a flap part (17, 18, 23) that can be moved relative thereto, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) injection molding the movable flap part (17, 18, 23 ) made of a second plastic material (57) within the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₂ ) demolding the housing part (10, 13, 53) from the first cavity and carrying out an intermediate treatment of the pre-molded part (41) obtained for the targeted reduction of tension within the pre-molded part (41).

4. The method according to claim 3, characterized in that as an intermediate treatment of the preform (41) this is fed to a thermal intermediate treatment.

5. The method according to claim 3, characterized in that as an intermediate treatment of the preform (41) vibrations are introduced or irradiated in these.

6. The method according to claims 1, 2 or 3, characterized in that a partially crystalline thermoplastic with a high melting temperature is used as the first plastic material.

7. The method according to claims 1, 2 or 3, characterized in that an amorphous high-temperature thermoplastic with a very high glass temperature is used as the first plastic material.

8. The method according to claims 1, 2 or 3, characterized in that the second plastic material (57) of the flap part (17, 18, 23) is a partially crystalline thermoplastic with compared to the plastic material from which the preform (41) is injection molded, has a lower melting temperature.

9. The method according to claims 1, 2 or 3, characterized in that the second plastic material (57) of the flap part (17, 18, 23) is an amorphous thermoplastic in comparison to the plastic material from which the pre-molded part (41) is injection molded has a lower melting temperature.

10. The method according to claims 1, 2 or 3, characterized in that the second plastic material (57) of the flap part (17, 18, 23) is a partially crystalline thermal plast with a higher melting temperature than the plastic material from which the preform (41) is injection molded.

11. The method according to claims 1, 2 or 3, characterized in that the second plastic material (57) of the flap part (17, 18, 23) is an amorphous thermoplastic with a higher melting temperature than the plastic material from which the preform 41 is injection molded.

12. A method for producing a throttle dapper unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) the Injection molding of the movable flap part (17, 18, 23) from a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₃ ) the molding according to the method step c) obtained flap part (17, 18, 23) within the pre-molded part (41) in a position of the flap part (17, 18, 23) forming a narrowest gap geometry within the pre-molded part (41) or in one during the injection zens of the second plastic material for the flap part (17, 18, 23) defined, sealing position of the flap part (17, 18, 23) within the pre-molded part (41).

13. The method according to claim 12, characterized in that the flap part (17, 18, 23) is injection molded inside the pre-molded part (41) in a position which enables a plunge through the gas passage opening (13).

14. The method according to claim 12, characterized in that the flap part (17, 18, 23) inside the pre-molded part (41) made of the second plastic material (57) in a plunging of the flap part (17, 18, 23) through the cross section of the Gas passage opening (13) preventing, inclined position is injection molded.

15. The method according to claims 2, 3 or 12, characterized in that according to the process steps di), d ₂ ), d ₃ ) and taking into account the expansion and / or contraction or post-crystallization and taking into account the theological behavior of the plastic materials used, How flow properties, molecular chain orientation and possible provisions, gaps (61, 62) between the flap part (17, 18, 23) and a gas passage opening (13) of the housing part (10) and the bearing points of the flap part (17, 18, 23) can be set specifically ,

16. The method according to claim 3, characterized in that the intermediate treatment of the preform (41) according to method step d ₂ ) takes place above the glass transition temperature of the first plastic material.

17. A method for producing a throttle dapper unit, comprising in the housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) the injection molding of the movable flap part (17, 18, 23) from a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d) after the application of a third material Method step a) on impression surfaces (63, 64) for the second plastic material (57) of the flap part (17, 18, 23) subsequently to be injection molded in the pre-molded part (41).

18. The method according to claim 17, characterized in that the third material is rubbed into the impression surfaces (63, 64) of the preform (41) as a lubricant or lubricant.

19. The method according to claim 17, characterized in that the third material in film form is applied as a spacer layer on the impression surfaces (63, 64) of the pre-molded part (41).

20. The method according to claims 17, 18, 19, characterized in that the third material in subsequent process steps from a two-component obtained Injection molded part (60) is partially or completely removed by a heat treatment.

21. A method for producing a throttle dapper unit comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) injection molding of the movable flap part (17, 18, 23) made of a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₅ ) the insertion of bushings (70, 71) in openings (14) of the pre-molded part (41) with rotation resistance to the pre-molded part (41) before or during the transfer of the pre-molded part (41) into the second cavity (42).

22. A method for producing a throttle dapper unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) injection molding of the movable flap part (17, 18, 23) made of a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₆ ) the insertion of bushings ( 70, 71) and back injection with anti-rotation with respect to the valve shaft parts (19, 20) of the valve shaft part (17, 18, 23) before or during the transfer of the preform (41) into the second cavity (42).

23. The method according to claims 21 or 22, characterized in that the bushings (70, 71) made of a metallic or non-metallic material with low Coefficient of friction with respect to the first or the second plastic material (57) are manufactured.

24. A method for producing a throttle valve unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) c) spatially separated from the first cavity and injection molding of the movable flap part (17, 18, 23) made of a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42), the injection points (15, 24) for Introducing the plastic materials for the housing part (10, 13, 53) and the flap part (17, 12, 23) into the cavities are positioned such that the flow orientation of chain molecules of the plastic materials and their reinforcement fillers and fillers the shrinkage behavior of the housing part (10, 13, 53) and the flap part (17, 18, 23) is influenced during the cooling phase so that the second plastic material (57) of the flap part (17, 18, 23) from the housing part (10, 13, 53) for setting the gaps (61, 62) disappears in a targeted manner.

25. A method for producing a throttle dapper unit, comprising a housing part (10, 13, 53) and a flap part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42), c) spatially separated from the first cavity, and the Injection molding of the movable flap part (17, 18, 23) from a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₇ ) in the introduction of a third material the gap geometries (61, 62) of the two-component pre-molded part (60), the gap geometries (61, 62) before the introduction of the third material outside the tightness specification and thereafter - if the third material is partially removed - within the tightness specification.

26. A method for producing a throttle valve unit, comprising a housing part (10, 13, 53) and a flap shaft part (17, 18, 23) that can be moved relative to the latter, 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) transferring the pre-molded part (41) of the housing part (10, 13, 53) obtained according to method step a) into a second cavity (42) spatially separated from the first cavity, c) injection molding of the movable flap part (17, 18, 23) made of a second plastic material (57) inside the pre-molded part (41) of the housing part (10, 13, 53) in the second cavity (42) and d ₈ ) introducing a fourth material in the gap geometries (61, 62) of the two-component pre-molded part (60) with bushings (70, 71), the gap geometries (61, 62) before the introduction of the fourth material outside the tightness specification and then - the ge if necessary, partial removal of the fourth material - within the tightness specification.