DE102023134976B3 - Acoustically optimized adjustment device - Google Patents

Abstract

The invention relates to an adjusting device for adjusting a vehicle flap or a vehicle door, comprising a housing (102), comprising a first housing part (103) and a second housing part (104), wherein the first housing part (103) is displaceable relative to the second housing part (104) along a longitudinal axis (L) of the housing (102) and the first housing part (103) and the second housing part (103) consist of a plastic, a pretensioning means (115) arranged in the housing,
wherein the prestressing means (115) prestresses the first housing part (103) and the second housing part (104) against one another parallel to the longitudinal axis (L) of the housing (102). The aim of providing an actuating device which is cost-effective and durable and has the quietest possible operation, and a method for producing a housing part or guide element for an actuating device which is reliable and cost-effective, is achieved in that at least the first housing part (103) consists of a mixture of a polymer with a sliding additive.

Description

The invention relates to an adjusting device for adjusting a vehicle flap or a vehicle door, wherein the adjusting device comprises at least one telescopically extendable housing and a pretensioning means arranged in the housing.

Actuating devices are known in practice which are arranged between two components movable relative to one another, in particular a pivotable vehicle flap and a vehicle body. The actuating devices have a spring system with at least one preloading means for preloading, which supports the actuating movement or the current position of the components to be moved in a rest state of the drive device. Linear drives, such as spindle drives, are particularly known. These usually comprise a first and a second housing part which can be displaced telescopically relative to one another and between which a preloading means such as a helical compression spring is arranged.

In addition, such preloading devices are also used in spring struts, which provide passive support or drive for a vehicle flap. A problem with such actuating devices is often that the preloading device installed therein causes undesirable impact noises during operation when the preloading device is bent radially in a direction perpendicular to a central axis of the spring part under axial load, causing one or more spring coils to strike an inner wall of the housing. It is known that using a spring with a curved spring axis can support the spring part within a hollow cylindrical spring guide, thus largely preventing the spring coils from striking during operation. However, due to the constant contact between the spring part coils and the spring guide, there may still be the problem that the spring part can cause noise due to friction with the surrounding spring guide or the housing, in particular due to the stick-slip effect of the spring coils against the guide surfaces of the spring guide.

DE 10 2018 123 186 A1 shows a spring support with a telescopic housing having a first housing part and a second housing part, wherein the first housing part is preloaded relative to the second housing part by means of a first spring part arranged between the first housing part and the second housing part. In order to reduce impact noises of the first spring part within the housing, a noise-reducing coating is provided on an inner side of the first housing part. The noise-reducing coating is designed as a flocking and/or a lacquer layer. A disadvantage is that the noise-reducing coating for preventing noise is relatively complex to apply to the inner side of the first housing part or the second housing part. Another disadvantage is that the abrasion resistance or corrosion resistance of the spring part itself is not significantly improved. In addition, when the spring coils come into contact with the guide surfaces of the first housing part or the second housing part, annoying noises can still occur because the spring coils execute noise-inducing frictional movements due to the suboptimal friction and sliding properties.

DE 10 2005 007 741 A1 shows a piston-cylinder unit with a spring part designed as a helical compression spring, wherein the helical compression spring has an elastic outer layer at least on its radially inwardly directed surface facing the cylinder of the piston-cylinder unit. The elastic outer layer is designed as flocking and comprises textile fibers and an adhesive layer, wherein the textile fibers are arranged in the adhesive layer. The disadvantage is that the noise reduction is achieved via a complex flocking of the helical compression spring, which does not provide sufficient abrasion resistance in the long term and, furthermore, prevents additional stick-slip movement insufficiently or only with considerable effort.

DE 10 2017 129 539 A1 shows a piston-cylinder unit with a spring sleeve, wherein the spring sleeve comprises an outer spring sleeve and an inner spring sleeve. The outer spring sleeve is displaceable relative to the inner spring sleeve along a longitudinal axis of the spring sleeve, with a spring preloading the outer spring sleeve relative to the inner spring sleeve along the longitudinal axis. The spring sleeve consists of a plastic mixture comprising plastics such as polyamide and additives such as polytetrafluoroethylene (PTFE).

CN 2 10 422 287 U shows an adjusting device for adjusting a vehicle flap or a vehicle door, comprising a telescopically extendable and retractable housing, wherein two housing parts are pretensioned against each other along the longitudinal axis of the housing by a spring arranged in the housing. The first housing part is made of glass fiber reinforced nylon, and the second housing part is designed as a hollow inner tube made of metal that is inserted into the hollow outer tube.

DE 10 2020 132 508 A1 shows an adjusting device for adjusting a vehicle flap or a vehicle door, comprising a telescopically adjustable and an extendable housing, wherein two housing parts are preloaded against each other along the longitudinal axis of the housing by a spring arranged in the housing. The first housing part and/or the second housing part preferably comprises or consists of at least one plastic, preferably a low-friction and/or self-lubricating plastic, particularly preferably a polyamide, a polyoxymethylene, a polycarbonate, or a polytetrafluoroethylene.

DE 10 2012 211 062 A1 shows an adjusting device for adjusting a vehicle flap or a vehicle door, comprising a telescopically extendable and retractable housing, wherein two housing parts are preloaded against each other along the longitudinal axis of the housing by a spring arranged in the housing. At least one of the housing parts is made of plastic.

The object of the invention is to provide an actuating device that is cost-effective, durable, and operates as quietly as possible. Furthermore, the object of the invention is to provide a method for producing a housing part or guide element for an actuating device that is reliable and cost-effective.

This object is achieved according to the invention by an adjusting device according to claim 1, a method for producing a housing part or a guide element for the adjusting device according to claim 8.

According to a first aspect of the invention, an adjusting device for adjusting a vehicle flap is provided, comprising a housing, wherein the housing comprises a first housing part and a second housing part, the first housing part being displaceable relative to the second housing part along a longitudinal axis of the housing, and the first housing part and the second housing part are made of a plastic, wherein at least the first housing part consists of a mixture of a polymer with a slip additive. Advantageously, the prestressing means arranged in the housing can slide off more easily upon contact with an inner wall of the housing parts, so that, in particular, a stick-slip effect generating disturbing noise is avoided. Furthermore, the adjusting device comprises a prestressing means arranged in the housing, which prestresses the first housing part and the second housing part against one another parallel to the longitudinal axis of the housing. The adjusting device according to the invention is characterized in that the slip additive is stearyl erucamide. Stearyl erucamide is known as a slip additive in the food industry. At room temperature, stearyl erucamide is a solid and can therefore easily be mixed into the polymer as granules during an injection molding process to produce the housing part. Stearyl erucamide can advantageously be added in granular form by the manufacturer, meaning that the slip additive is already contained in the granules used for the injection molding process. Alternatively, stearyl erucamide can also be added separately in liquid form during the injection molding process. In this case, the polymer and the slip additive are used as separate solids and only mixed together after melting.

The polymer is particularly preferably a polyamide. Further preferred is polyamide 6. Polyamide 6 is particularly well-suited for producing plastic parts using injection molding, as it melts to a low viscosity without decomposing. Further preferred is the plastic being fiber-reinforced. Advantageously, the first housing part is thus particularly robust and therefore durable.

In a preferred embodiment, the plastic is formed as a glass fiber-reinforced polyamide with a slip additive. Particularly preferably, the plastic is formed as a glass fiber-reinforced polyamide 6 with a glass fiber content of 30%. In an advantageous embodiment, the slip additive is added in a proportion of up to one percent by weight based on the total weight of the polymer. Particularly preferably, the proportion of the slip additive is 0.5 to 1 percent by weight based on the total weight of the polymer.

In an advantageous embodiment, the adjusting device comprises a guide device with at least one first guide element made of plastic for guiding the pretensioning means. The first guide element is preferably designed as a hollow cylinder or guide housing part which is firmly connected to the first housing part. In a preferred development, the first guide element is at least partially surrounded by the first housing part, wherein the pretensioning means is arranged radially between the first guide element and the first housing part. This advantageously results in improved guidance of the pretensioning means in the housing. In particular, the inside of the first housing part and the outside of the first guide element form guide surfaces between which the pretensioning means can be securely guided.

In a particularly preferred embodiment, the first guide element consists of a mixture of a polymer with a sliding additive. This advantageously ensures that the pretensioning means, for example a helical compression spring, is as can slide smoothly along the guide surfaces provided by the first housing part and the first guide element and does not generate any disturbing noises. Particularly preferably, the first guide element is made of the same plastic as the first housing part.

The guide device expediently comprises a second guide element made of plastic, which is telescopically movable relative to the first guide element. Particularly preferably, the second guide element is rigidly connected to the second housing part. Furthermore, the second guide element advantageously consists of a mixture of a polymer with a sliding additive. This advantageously provides an inner guide surface with low frictional resistance over the entire length of the preloading means.

According to a further aspect of the invention, a method for producing a plastic housing part is provided, comprising, in a first method step, providing a granulate of a plastic material, in a second method step, heating and melting the granulate, in a third method step, injecting the liquefied plastic material into an injection mold, in a fourth method step, cooling the plastic material, and, in a fifth method step, demolding the plastic housing part from the injection mold. The method according to the invention is characterized in that the granulate contains a polymer and stearyl erucamide as a slip additive.

In a first embodiment of the method according to the invention, the polymer and the slip additive are contained as a mixture in the granulate. Advantageously, the granulate is provided by the manufacturer of the granulate and can be readily used during the injection molding process according to the method according to the invention for producing the housing part or the guide element for the actuating device. Alternatively, however, it can also be provided that the polymer and the slip additive are present as separate solids in the granulate as a mixture and are mixed with one another during the process step of melting the granulate.

Further advantages, developments and features of the invention will become apparent from the following description of preferred embodiments and from the dependent claims.

• 1 zeigt ein erstes bevorzugtes Ausführungsbeispiel einer erfindungsgemäßen Stellvorrichtung in einer Querschnittsansicht.
• 2 zeigt ein zweites bevorzugtes Ausführungsbeispiel einer erfindungsgemäßen Stellvorrichtung in einer teilweise aufgeschnittenen Seitenansicht

The invention will now be explained in more detail with reference to the accompanying drawings using preferred embodiments of the invention.

• 1 shows a first preferred embodiment of an adjusting device according to the invention in a cross-sectional view.
• 2 shows a second preferred embodiment of an adjusting device according to the invention in a partially cut-away side view

1 shows a preferred embodiment of a support device 1 in a cross-sectional view. The support device 1 is designed as a spindle drive and comprises a housing 2, wherein the housing 2 comprises a first housing part 3 and a second housing part 4, which are arranged to be displaceable relative to one another. In the present case, the second housing part 4 is guided in the first housing part 3 and is telescopically displaceable, so that the overall length of the housing 2 can be telescopically varied by displacing the first housing part 3 relative to the second housing part 4.

The support device 1 further comprises a hollow cylindrical sleeve 5, wherein the sleeve 5 is arranged at a first end 3a of the first housing part 3 and is firmly connected to this first end 3a. A first end 5a of the sleeve 5 surrounds a section of the first end 3a of the first housing part 3 and is connected to it via a press fit. A first connection element 6 designed as a ball socket is arranged at a second end 5b of the sleeve 5 opposite the first end 5a of the sleeve 5, such that the support device 1 can be articulated to one of the vehicle flap and the vehicle body via the first connection element 6.

The second housing part 4 has a first end 4a, which is pushed into the first housing part 3. A second connecting element 7 designed as a ball socket is fastened to a second end 4b of the second housing part 4, opposite the first end 4a, so that the support device 1 can be articulated to the other end of the vehicle flap and the vehicle body via the second connecting element 7.

Arranged in the housing 2 is a spindle gear 8, which comprises a spindle rod 9 and a spindle nut 10 arranged on the spindle rod 9. The spindle rod 9 and the spindle nut 10 are arranged in a telescopic guide device 11, wherein the guide device 11 comprises a first guide element 12 and a second guide element 13 telescopically guided in the first guide element 12.

The spindle rod 9 is mounted rotatably about a spindle axis S in a bearing device 14 designed as a ball bearing arranged in the first housing part 3. The spindle nut 10 is fixedly connected to a first end 13a of the second guide element 13, so that upon rotation of the spindle rod 9 about the spindle axis S, the second guide element 13 is axially displaced together with the spindle nut 10 relative to the first guide element 12.

The first guide element 12 is firmly connected to the first housing part 3 by a first end 12a, and the second guide element 13 is firmly connected to the second connection element 7 and thus also to the second housing part 4 by a second end 13b opposite the first end 13a, since the second connection element 7 is firmly connected to the second end 4b of the second housing part 4. As a result, when an external force acts on the housing 2, in particular by adjusting a vehicle flap coupled to the support device 1 on one side by means of a drive device or by manual adjustment in which a user exerts a force on the vehicle flap, or simply by the weight of the vehicle flap acting on the housing 2 in the direction of the spindle axis S, the spindle rod 9 is rotated about the spindle axis S.

The support device 1 further comprises a prestressing means 15 designed as a helical compression spring, which is supported on one side on the first end 12a of the first guide element 12, which is firmly connected to the first housing part 3, and on the other side on the second end 4b of the second housing part 4, so that the prestressing means 15 prestresses the second housing part 4 relative to the first housing part 3 in the extension direction. Advantageously, the prestressing means 15 causes the support device 1 to prestress the vehicle lid in the opening direction or at least to counteract a closing movement of the vehicle lid.

In the embodiment shown here, the first housing part 3, the second housing part 4, the first guide element 12, and the second guide element 13 are made of plastic and were manufactured by an injection molding process. In the embodiment shown here, the plastic is glass fiber reinforced polyamide 6 with a glass fiber content of 30%, with the polyamide 6 mixed with stearyl erucamide as a sliding additive.

Since the first housing part 3 and the second housing part 4 radially surround the preloading means 15, which is designed as a helical compression spring, and the first guide element 12 and the second guide element 13 act as an inner guide for the preloading means 15, the situation can arise that the preloading means 15 can touch the outer guide surfaces 3', 4' provided by the first housing part 3 and the second housing part 4, which are the inner surfaces of the first housing part 3 and the second housing part 4 facing the preloading means 15, and thus come into frictional contact with them. Likewise, the outer surfaces of the first guide element 12 and the second guide element 13 provide inner guide surfaces 12', 13', which can come into contact with the spring coils of the preloading means 15.

Since during the opening or closing movement a relative movement of the outer windings of the pretensioning means 15 to the guide surfaces 3', 4', 12', 13' occurs, the outer windings 16 of the pretensioning means 15 slide significantly more easily from the guide surfaces 3', 4'; 12', 13' due to the fact that the first housing part 3, the second housing part 4, the first guide wall 12 and the second guide groove 13 are made of a plastic which is a mixture of a polymer and a sliding additive and accordingly generate no or only very little disturbing noise.

2 shows a second preferred embodiment of an adjusting device 101 according to the invention in a partially cut-away side view. The adjusting device 101 is designed as a spring strut and comprises a housing 102 extending along a longitudinal axis L, which is formed from a first housing part 103 and a second housing part 104. Both the first housing part 103 and the second housing part 104 are designed as half-open hollow cylinders made of plastic, with the closed end 103a of the first housing part 103 forming a first housing end 105 and the closed end 104a of the second housing part 104 forming a second housing end 106. The plastic from which the first housing part 103 and the second housing part 104 are made is a mixture of polyamide 6 and stearyl erucamide as a slip additive.

The first housing part 103 has a larger outer and inner diameter than the second housing part 104, wherein the second housing part 104 is inserted into the first housing part 103, so that the first housing part 103 and the second housing part 104 are displaceable relative to one another parallel to the longitudinal axis L of the housing 102. Due to the fact that an inner diameter of the first housing part 103 approximately corresponds to the outer diameter of the second housing part 104, the first housing part 103 forms a guide for the second housing part 104, so that no or only a slight displacement of the first housing part 103 and the second housing part 104 in the radial direction tion relative to the longitudinal axis L during an axial displacement of the housing parts 103, 104 relative to one another.

The above-described arrangement of the two housing parts 103, 104 thus forms the completely closed housing 102, wherein the housing 102 encloses a construction space 107 arranged between the first housing end 105 and the second housing end 106. The volume of the construction space 107 is correspondingly variable, since the first housing end 105 and the second housing end 106 can be displaced relative to one another parallel to the longitudinal axis L.

A first connection element 108 is arranged at the first housing end 105, and a second connection element 109 is arranged at the second housing end 106, wherein the first connection element 108 and the second connection element 109 are each designed as ball sockets. Advantageously, the actuating device 101 can thus be connected in an articulated manner to a vehicle body or a vehicle flap, such that the vehicle flap, driven by the actuating device 101, can be automatically moved between an open and a closed position by displacing the first housing part 103 relative to the second housing part 104 parallel to the longitudinal axis L.

A guide device 111 with a first guide tube 112 and a second guide tube 113 is arranged in the installation space 107 or in the housing 102 between the first housing end 105 and the second housing end 106. The first guide tube 112 and the second guide tube 113 are each designed as hollow cylinders, with the first guide tube 112 having a larger outer diameter than the second guide tube 113. The second guide tube 113 can thus be telescopically displaced relative to the first guide tube 112 parallel to the longitudinal axis L of the housing 102, wherein the length of the protruding part of the second guide tube 113 is smaller in a retracted state of the adjusting device 101, in which a distance between the first housing end 105 and the second housing end 106 is minimal, than in an extended state of the adjusting device 101, in which the distance between the first housing end 105 and the second housing end 106 is maximum. The first guide tube 112 is firmly coupled to the first housing part 103 via the first connecting element 108, and the second guide tube 113 is firmly coupled to the second housing part 104 via the second connecting element 109.

The actuating device 101 further comprises a prestressing means 115 arranged in the installation space 107 or the housing 102, which in the exemplary embodiment shown here is designed as a helical compression spring. A first end 115a of the prestressing means 115 rests against the first connecting element 108, and a second end 115b of the prestressing means 115 rests against the second connecting element 109. As a result, the prestressing means 115 prestresses the first housing part 103 and the second housing part 104 against each other in the direction of the extended state of the actuating device 101, i.e., the state in which the distance between the first housing end 105 and the second housing end 106 is maximum.

Each of the spring coils 116 of the prestressing means 115 concentrically revolves around the spring axis F. The spring axis F, in turn, runs helically around the longitudinal axis L of the housing 102. The distance of the spring axis F from the longitudinal axis L, which is perpendicular to the longitudinal axis L, is constant in the exemplary embodiment shown here. Advantageously, this results in all spring coils 116 being arranged eccentrically to the longitudinal axis L, and thus each spring coil 116 having an outer coil section 116a with a maximum distance from the longitudinal axis L and an inner coil section 116b with a minimum distance from the longitudinal axis L.

Furthermore, as a consequence of the fact that the windings 116 are arranged eccentrically to the longitudinal axis L or that the spring axis F runs helically around the longitudinal axis L, the outer winding section 116a is in contact with an outer guide surface 104' formed by the inner side of the second housing part 104 at a maximum radial distance from the longitudinal axis L. The second housing part 104 thus advantageously functions as a guide or radial support for the prestressing means 115. In the preferred embodiment considered here, due to the helical course of the spring axis F around the longitudinal axis L, all spring windings 116 which are arranged within the second housing part 104 are supported by the inner side 104' of the second housing part 104 at a point of contact.

As a further consequence of the eccentric arrangement of the spring coils 116 relative to the longitudinal axis L or from the fact that the spring axis F helically revolves around the longitudinal axis L, it follows that the inner coil section 116b is in contact with an inner guide surface 112' of the first guide tube 112 of the guide device 111, formed by the outer side, at a minimal radial distance from the longitudinal axis L. Advantageously, the first guide tube 112 of the actuating device 101, which is designed as a spring strut, thus functions as a radial support for the spring coils 114 surrounding it. The second guide The guide tube 113 serves as a second guide section for the pretensioning means 115.

In the preferred embodiment considered here, due to the helical course of the spring axis F around the longitudinal axis L, all windings 116 that encircle the first guide tube 112 of the guide device 111 are supported by the outer side 112' of the first guide tube 112 at at least one contact point. Advantageously, both the first guide tube 112 and the second guide tube 113 are made of the same plastic as the first housing part 103 and the second housing part 104, namely a mixture of polyamide 6 and stearyl erucamide as a sliding additive. Advantageously, the pretensioning means 115 with its windings 116 can slide with significantly lower frictional resistance on the outer guide surfaces 104', 103' of the first housing part 103 and the second housing part 104 and the inner guide surfaces 112', 113' of the first guide tube 112 and the second guide tube 113.

The invention has been explained above using exemplary embodiments in which the first housing part 3; 103 has a larger outer and inner diameter than the second housing part 4; 104. It is understood that the first housing part 3; 103 can have a smaller outer and inner diameter than the second housing part 4; 104, wherein the second housing part 4; 104 radially surrounds the first housing part 3; 103 in sections. The same applies to the first guide element 12; 112 and the second guide element 13; 113. In the exemplary embodiments described above, the first guide element 12; 112 had a larger outer and inner diameter than the second guide element 13; 113. It is understood that the first guide element 12; 112 can have a smaller outer and inner diameter than the second guide element 13; 113, wherein the second guide element 13; 113 radially surrounds the first guide element 12; 112 in sections. The only decisive factor for the invention is that those components of the adjusting device that may come into contact with the preloading means consist of a mixture of a polymer and a sliding additive.

Claims (10)

Adjusting device (1; 101) for adjusting a vehicle flap or a vehicle door, comprising a housing (2; 102), comprising a first housing part (3; 103) and a second housing part (4; 104), wherein the first housing part (3; 103) is displaceable relative to the second housing part (4; 104) along a longitudinal axis (L) of the housing (2; 102) and the first housing part (3; 103) and the second housing part (3; 103) are made of a plastic, a prestressing means (15; 115) arranged in the housing, wherein the prestressing means (15; 115) prestresses the first housing part (3; 103) and the second housing part (4; 104) against each other parallel to the longitudinal axis (L) of the housing (2; 102), wherein at least the first housing part (3; 103) is made of a mixture of a polymer with a Slip additive, characterized in that the slip additive is stearyl erucamide. Adjusting device according to Claim 1 , characterized in that the plastic is designed as glass fiber reinforced polyamide. Adjusting device according to one of the preceding claims, characterized in that the polymer is polyamide 6. Adjusting device according to one of the preceding claims, characterized in that the plastic is glass fiber reinforced polyamide 6 with a glass fiber content of 30%. Adjusting device according to one of the preceding claims, characterized in that the slip additive is added in a proportion of up to one percent by weight based on the total weight of the polymer. Adjusting device according to one of the preceding claims, characterized in that a guide device (11; 111) with a first guide element (12; 112) made of plastic for guiding the pretensioning means (15; 115) is arranged in the housing (2; 102). Adjusting device according to Claim 6 , characterized in that the first guide element (12; 112) consists of a mixture of a polymer with a sliding additive. Method for producing a housing part (3; 4; 103; 104) or a guide element (12; 13; 112; 113) from plastic, comprising the steps of: providing granules of a plastic, heating and melting the granules, injecting the liquefied plastic into an injection mold, cooling the plastic, demolding the housing part (3; 4; 103; 104) or guide element (12; 13; 112; 113) from the injection mold, characterized in that the granules contain a polymer and stearyl erucamide as a slip additive. Procedure according to Claim 8 , characterized in that the polymer and the slip additive are contained as a mixture in the granulate. Procedure according to Claim 8 , characterized in that the polymer and the slip additive are present as separate solids in the granules and are mixed together when the granules are melted.

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