DE202010016474U1 - Spindle drive for an adjusting element of a motor vehicle - Google Patents

Abstract

Spindle drive for an adjusting element (1) of a motor vehicle with a drive motor (2), a spindle-spindle nut gear (3) connected downstream of the drive motor (2) for generating linear drive movements and with two connections (4, 5) for deriving the drive movements, at least one Helical compression spring (8) aligned on the spindle longitudinal axis (7) is provided for preloading the spindle drive into the extended state, characterized in that the course of the center line (9) of the helical compression spring (8) is at least partially straight in the unassembled, force-free state deviates.

Description

The present invention relates to a spindle drive for an adjusting element of a motor vehicle according to the preamble of claim 1 and to a helical compression spring of such a spindle drive according to claim 13.

The present spindle drive can be used for all possible adjustment of a motor vehicle application. Examples include a flap, in particular a tailgate, a trunk lid, a hood, a side door, a cargo compartment lid, a lifting roof or the like of a motor vehicle.

A well-known spindle drive ( DE 20 2005 003 466 U1 ), from which the invention proceeds, is used to adjust a tailgate of a motor vehicle. The spindle drive is equipped with a drive motor and a spindle spindle nut transmission connected downstream of the drive motor for generating drive movements. For discharging the drive movements two connections are provided, which are biased by means of several helical compression springs in the extended state.

In the known spindle drive, the spindle nut is connected to a guide tube, which serves on the one hand the leadership of the spindle nut protruding through the spindle and the other hand serves via a guide sleeve of the leadership of the helical compression springs.

At least one of the helical compression springs is biased both in the extended position and in the retracted position of the spindle drive. Due to the elongated design of the helical compression spring causes the bias a slight lateral buckling of the helical compression spring, so that the center line of the helical compression spring in the retracted position deviates from a straight course.

At low bias the center line of the helical compression spring runs regularly in an arc. Upon further increase in the bias voltage, for example, by the retraction of the spindle drive, it comes to a folding of the spring such that the center line assumes the course of a sinusoid in a first approximation. With further bias, it comes again and again to a turning of the spring, wherein the frequency of the sinusoid always increases relative to the longitudinal extent of the helical compression spring.

The above turning over the helical compression spring hardly occurs predictably in the course of the adjustment of the spindle drive from the extended position to the retracted position. This leads each time to a lateral abutment of the helical compression spring on the housing of the spindle drive or on the guide sleeve. This is accompanied by corresponding crackling noises, which are understood by the user as a loss of comfort.

Attempts have already been made successfully to adapt the helical compression springs of the spindle drive in question to the geometric conditions prevailing in the spindle drive ( DE 20 2009 006 216 U1 ). For this purpose, the diameters of the spring coils were designed differently over the length of the helical compression springs. The above turning over the helical compression spring can not be avoided in full extent.

The invention is based on the problem, the known spindle drive in such a way and further develop that a reversal of the helical compression spring is counteracted during the adjustment of the spindle drive.

The above problem is solved in a spindle drive according to the preamble of claim 1 by the features of the characterizing part of claim 1.

It is essential to realize that the lateral deformation of the helical compression spring can be set reproducibly during clamping when the course of the center line of the helical compression spring at least partially deviates from a straight course even in the unassembled, force-free state.

By the term "center line of the helical compression spring" is meant in the present case the line which connects all geometrical centers of the individual spring coils.

Preferably, the helical compression spring is designed so that in the assembled state in a reproducible manner at one - based on the cross section of the helical compression spring 8th - On the inside guide surface and / or on an outer guide surface laterally supported (claim 2).

In this case, the helical compression spring can be assigned individual, inner and / or outer support points over which the helical compression spring is laterally supported in the mounted state, which may be advantageous in terms of the resulting friction between the helical compression spring and the guide surface (claim 3).

Alternatively or additionally, it may also be provided that the Helical compression spring in the mounted state along at least one inner and / or outer support line laterally supported, which guarantees a uniform load on the housing of the spindle drive (claim 4).

The above support via a support line can best be achieved by the center line according to claim 10 is substantially helical.

In the particularly preferred, structurally simple and at the same time effective variant according to claim 11, it is provided in the region of the helical compression spring, in which at least in the mounted, retracted state lateral support is desired to provide a kind of kink, resulting in a corresponding bulge the Centerline of the helical compression spring expresses. Thus, the respective lateral support points can be adjusted in a relatively simple constructive manner.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. In the drawing shows

1 in a very schematic representation of the rear area of a motor vehicle with a tailgate, which is equipped with a proposed spindle drive,

2 the spindle drive according to 1 in the extended position in a sectional side view,

3 the spindle drive according to 2 in sectional views a) along the section line AA, b) along the section line BB, c) along the section line CC,

4 the helical compression spring of the spindle drive according to 2 in unassembled, force-free state in longitudinal section,

5 the helical compression spring of the spindle drive according to 2 in the unmounted, force-free state in a perspective view and

6 the helical compression spring of the spindle drive according to 2 in a further embodiment in the unassembled, force-free state in a perspective view.

The spindle drive shown in the drawing serves for the motorized adjustment of an adjusting element designed as a tailgate 1 , This is advantageous, but not restrictive to understand. Rather, the proposed spindle drive can be used for all possible adjusting elements of a motor vehicle, as will be explained below.

The spindle drive is equipped with a drive motor 2 , a drive motor 2 downstream spindle spindle nut transmission 3 for generating linear drive movements and with two connections 4 . 5 equipped to remove the drive movements. Between the drive motor 2 and the spindle-spindle nut transmission 3 is here and preferably one designed in particular as a planetary gear intermediate gear 6 switched, but for the proposed solution but does not matter.

The spindle drive points to the spindle axis 7 aligned, here one-piece helical compression spring 8th on, which serves to bias the spindle drive in the extended state. In principle, several helical compression springs can also be used here.

The helical compression spring 8th the proposed spindle drive is particularly important in the field of application of the motorized adjustment of tailgates special importance. It affects the weight of the tailgate 1 opposite. Preferably, the helical compression spring 8th with regard to the weight of the tailgate 1 designed so that the resulting state comes as close as possible to a state of equilibrium. In terms of an optimal approach, as mentioned above, several, in particular different helical compression springs 8th be provided. The following is representative of possibly several helical compression springs 8th only from a single helical compression spring 8th the speech.

Essential is mm that the course of the midline 9 the helical compression spring 8th in any case deviates at least in sections from a straight course in the unmounted, force-free state. This can best be done according to the illustration 4 take the unassembled, power-free state of the helical compression spring 8th shows. The straight course of the helical compression spring 8th and the spring longitudinal axis are here with the common reference numeral " 10 "Marked. The spring longitudinal axis 10 and the spindle axis 7 are identical here and preferably.

By the term "force-free state of the helical compression spring" is meant here the state in which no forces from the outside to the helical compression spring 8th Act.

With the proposed embodiment of the helical compression spring 8th can be the lateral deformation of the helical compression spring 8th in the accurately control the mounted state. This was explained above.

In order to better represent the proposed teaching, the structural design of the spindle drive is first explained.

2 shows that the proposed spindle drive housing 13 in which the spindle spindle nut transmission 3 , the helical compression spring 8th and the drive motor 2 are arranged. Accordingly, there is also the above-mentioned intermediate gear 6 in the case 13 , Basically, the drive motor 2 and / or the intermediate gear 6 as well as other drive components and clutches or the like outside of the housing 13 be arranged. Optionally, then a further housing for these drive components is provided.

2 further shows that the housing 13 one with one of the two connections 4 connected inner tube 13a and one with the other connection 5 connected, telescopic against the inner tube 13a movable outer tube 13b having.

The spindle 14 of spindle spindle nut transmission 3 is opposite one of the two ports 4 . 5 , here and preferably opposite to the inner tube 13a connected connection 4 , axially fixed and rotatably mounted. The spindle nut 15 of spindle spindle nut transmission 3 on the other hand is with the other connection 5 , here and preferably with the outer tube 13b connected connection 5 , via a guide tube 16 connected, depending on the position of the spindle drive, a spindle portion outside the guide tube 16 and a spindle portion within the guide tube 16 is located.

The helical compression spring 8th encloses the spindle 14 and extends substantially the entire length of the spindle 14 , It is conceivable that the helical compression spring 8th also only over a longitudinal section of the spindle 14 extends. In the illustrated embodiment is associated with the fact that the helical compression spring 8th also the guide tube 16 encloses and that the helical compression spring 8th over the entire length of the guide tube 16 extends. Again, it may be provided that the helical compression spring 8th only over a longitudinal section of the guide tube 16 extends.

The guide tube 16 forms inside an additional guide for the spindle 14 of spindle spindle nut transmission 3 , This is the spindle 14 end with a sliding element 14a fitted. The guide tube 16 also serves with its outside the leadership of the helical compression spring 8th ,

In the present case, it is the helical compression spring 8th is already biased in its assembled state in the extended position of the spindle drive. This means that the spring must be clamped during assembly accordingly.

A synopsis of 2 and 3 shows that the helical compression spring 8th in the assembled state at one - based on the cross section of the helical compression spring 8th - Outer guide surface laterally supported by the housing 13 the spindle drive is provided. In principle, it is also conceivable that a support via a - based on the cross section of the helical compression spring 8th - Inside guide surface takes place. Such a guide surface could here for example by a on the guide tube 16 be deferred guide sleeve formed. The lateral support of the helical compression spring 8th acts a buckling of the helical compression spring 8th opposite.

The helical compression spring 8th can in a variant of at least one, - based on the cross section of the helical compression spring 8th - Have internal and / or external support point, via which the helical compression spring 8th laterally supported in the mounted state. Such a support point provides a substantially punctual, lateral support of the helical compression spring 8th ready. This can be with the in 6 illustrated helical compression spring 8th realize, as shown below.

In the in the 2 to 5 illustrated embodiment, it is however provided that the helical compression spring 8th in the mounted state along at least one - based on the cross section of the helical compression spring 8th - external support line 8a supported laterally, wherein the support line 8a here and preferably substantially helically along the spring longitudinal axis 10 extends. Again, it may in principle be provided that the support takes place via an inner support line, which optionally has one on the guide tube 16 deferred guide sleeve extends.

With the above support line 8a each axial position is a point of contact 8b between the helical compression spring 8th and the housing 13 intended. When walking the spring longitudinal axis 10 the contact point is running 8b between the helical compression spring 8th and the housing 13 several times around the spring's longitudinal axis 10 around.

In a particularly preferred embodiment, the above, linear support of the helical compression spring 8th over the entire length of the helical compression spring 8th intended. Accordingly, the support line extends 8a in the assembled, retracted state and / or in the mounted, extended state over the entire length of the helical compression spring 8th , It is also conceivable in this context that the support line 8a in certain areas along the spring axis 10 is interrupted.

Of particular importance is the fact that the helical compression spring 8th is designed so that between the extended position and the retracted position of the spindle drive the course of the center line 9 the helical compression spring 8th apart from an at least partially axial compression remains substantially unchanged. This is accompanied by the advantageous circumstance that during the motorized adjustment of the spindle drive to no above-mentioned turning over the helical compression spring 8th comes.

A synopsis of 4 and 5 shows that the midline 9 the helical compression spring 8th in unassembled, force-free condition based on the spring longitudinal axis 10 has an alternating course in two spatial directions, wherein here and preferably the period length over the spring longitudinal axis 10 is always constant. It is also possible that the period length over the spring longitudinal axis 10 is variable, which is an optimal adaptation of the helical compression spring 8th allowed to the respective constructive boundary conditions.

The alternating course can also be provided only in one spatial direction, which is the production of the helical compression spring 8th considerably simplified.

For the course of the midline 9 the helical compression spring 8th In the unmounted, power-free state, numerous advantageous variants are conceivable. In a particularly preferred embodiment, the center line runs 9 at least in sections, at least in one spatial direction substantially in the manner of a vibration curve, here and preferably in the manner of a sinusoid. It is also conceivable that the midline 9 the helical compression spring 8th runs in the manner of a rectangular curve or the like.

In the particularly preferred embodiment according to 4 and 5 runs the middle line 9 the helical compression spring 8th in the unassembled, force-free state, at least in sections, essentially helically. With this helical course of the midline 9 can be a support of the helical compression spring 8th along an above-mentioned support line 8a to reach. Particularly advantageous is the fact that the helical compression spring 8th through its helical centerline 9 with an additional compliance in a direction perpendicular to the spring longitudinal axis 10 Is provided. This simplifies the assembly of the helical compression spring 8th and reduces the friction between the helical compression spring 8th and the housing 13 ,

A preferred design sees a very specific number of the periods of the alternating course in the unassembled, force-free state of the helical compression spring 8th in front. This number corresponds to the number of periods that results when a helical compression spring 8th of ideally cylindrical shape and otherwise of identical design would be mounted in the spindle drive. This ensures that the lateral deformation of the helical compression spring that occurs during assembly is avoided 8th by the shape of the helical compression spring 8th is specifically supported, so that an undefined turning of the helical compression spring 8th can be largely avoided during the adjustment of the spindle drive.

6 shows a further preferred embodiment of a helical compression spring 8th , with which in the assembled state predefined support points can be realized in the above sense. Here it is intended that the midline 9 the helical compression spring 8th in the area of the unrepresented, lateral support points in the unassembled, force-free state in each case a lateral bulge 9a having. At the in 6 illustrated and so far preferred embodiment are the bulges 9a in three directions 17 . 18 . 19 intended. The spatial directions 17 . 18 . 19 are each perpendicular to the spring axis 10 where two adjacent spatial directions 17 . 18 . 19 each enclose an angle of 120 °. The spatial directions 17 . 18 . 19 are in 6 for clarity, shown as levels.

It can be the representation in 6 to take the fact that the individual bulges 9a some predefined kinks for the helical compression spring 8th form, so that in the mounted state, a predefined buckling, so a predefined lateral deformation of the helical compression spring 8th he follows. In this way, the lateral deformation helical compression spring can be 8th In the assembled state, easily control, so that it turns over the helical compression spring 8th can not come.

Basically, it can also be provided here that the Helical compression spring 8th has a single bulge in unmounted, power-free state. In a particularly preferred embodiment, it is provided that the center line 9 the helical compression spring 8th has an arcuate course in the unmounted, force-free state.

Against the background that an above turning over the helical compression spring 8th should be avoided as far as possible, the helical compression spring 8th preferably designed so that the number of lateral inboard support points and / or the number of lateral outboard support points in the mounted, retracted state is identical to the mounted, extended state.

In the illustrated and so far preferred embodiment, the diameter of the spring coils over the length of the helical compression spring 8th constant. It is also conceivable that the helical compression spring 8th For its adaptation to the prevailing geometric conditions in the spindle drive spring coils of different diameters. To possible variants this may on the German utility model 20 2009 006 216.3 referred to by the Applicant, the content of which is the subject of the present application.

It has already been pointed out that the proposed spindle drive can be applied to all possible adjusting elements of a motor vehicle. Only by way of example may be referred to applications in which the adjusting element 1 a tailgate, a trunk lid, a door, in particular a side door, a hood or the like, of a motor vehicle.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202005003466 U1 [0003]
• DE 202009006216 U1 [0008]
• DE 202009006216 U [0054]

Claims (13)

Spindle drive for an adjusting element ( 1 ) of a motor vehicle with a drive motor ( 2 ), a drive motor ( 2 ) downstream spindle spindle nut transmission ( 3 ) for generating linear drive movements and with two connections ( 4 . 5 ) for discharging the drive movements, wherein at least one on the spindle longitudinal axis ( 7 ) oriented helical compression spring ( 8th ) is provided for biasing the spindle drive in the extended state, characterized in that the course of the center line ( 9 ) of the helical compression spring ( 8th ) deviates at least in sections from a straight course at least in the unmounted, force-free state. Spindle drive according to claim 1, characterized in that the helical compression spring ( 8th ) in any case in the mounted state on an inner guide surface and / or on an outer guide surface laterally supported. Spindle drive according to claim 1 or 2, characterized in that the helical compression spring ( 8th ) has at least one, inner and / or outer support point, via which the helical compression spring ( 8th ) is laterally supported in the mounted state. Spindle drive according to one of the preceding claims, characterized in that the helical compression spring ( 8th ) in the assembled state along at least one inner and / or outer support line ( 8a ) is supported laterally, preferably, that the support line ( 8a ) substantially helically along a spring longitudinal axis ( 10 ). Spindle drive according to one of the preceding claims, characterized in that the support line ( 8a ) in the mounted, retracted state and / or in the mounted, extended state over the entire length of the helical compression spring ( 8th ). Spindle drive according to one of the preceding claims, characterized in that between the extended position and the retracted position of the spindle drive the course of the center line ( 9 ) of the helical compression spring ( 8th ) remains substantially unchanged except for an at least partially axial compression. Spindle drive according to one of the preceding claims, characterized in that the center line ( 9 ) of the helical compression spring ( 8th ) in the unmounted, force-free state with respect to a spring longitudinal axis ( 10 ) has at least in one spatial direction, preferably in two spatial directions, an alternating course, preferably that the period length over the spring longitudinal axis ( 10 ) is constant or variable. Spindle drive according to one of the preceding claims, characterized in that the number of periods of the alternating course in the unmounted, force-free state corresponds to the number of internal lateral support points or the number of external lateral support points in the mounted, retracted and / or extended state. Spindle drive according to one of the preceding claims, characterized in that the center line ( 9 ) of the helical compression spring ( 8th ) in the unmounted, force-free state at least in sections, at least in a spatial direction substantially in the manner of a vibration curve, in particular in the manner of a sinusoid, a rectangular curve o. The like. Spindle drive according to one of the preceding claims, characterized in that the center line ( 9 ) of the helical compression spring ( 8th ) in the unassembled, force-free state is at least partially substantially helical. Spindle drive according to one of the preceding claims, characterized in that the center line ( 9 ) of the helical compression spring ( 8th ) in the region of the at least one lateral support point in the unassembled, force-free state each have a lateral bulge ( 9a ) having. Spindle drive according to one of the preceding claims, characterized in that the diameter of the spring coils along the spring longitudinal axis ( 10 ) is constant, or that the helical compression spring ( 8th ) to whose adaptation to the prevailing geometric conditions in the spindle drive spring coils of different diameters. Spindle drive according to one of the preceding claims, characterized in that the adjusting element ( 1 ) a tailgate, a trunk lid, a door, in particular a side door, an engine hood o. The like., Of a motor vehicle.

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