SLIDING DOOR DRIVE FOR A MOTOR VEHICLE

Description

[0001] The invention relates to a sliding door drive for a motor vehicle with a drive unit comprising a housing, wherein the housing comprises a lower housing part, a middle housing part and a housing cover, an electric drive, a gear connected downstream of the drive and a clutch, wherein at least one winding drum arranged on a shaft can be driven by means of the drive unit and the shaft is mounted at least twice in the housing, in particular at the axial ends of the shaft, wherein axial ends mean the areas of the shaft that lie outside the receptacle or bearing surfaces of the winding shaft, wherein the shaft is inserted into a receptacle of the ring gear, so that the shaft can be driven by means of the ring gear, wherein the ring gear is received in a plain bearing in the middle part of the housing, and wherein the receptacle of the ring gear is reinforced with a steel bushing.

[0002] Electrically operated sliding doors are being used more and more in today's motor vehicles. This makes it easier to access the vehicle and / or gives children, for example, the opportunity to operate even large sliding doors for getting in and out. Sliding doors are used in vans as well as in passenger cars. The sliding doors differ in size and weight. With large sliding doors, the sealing pressures that must be overcome also play a crucial role in the electrical operation of the sliding doors. This means that different requirements can be placed on a sliding door drive. In many cases, cables are used to operate, i.e. move or slide the doors.

[0003] For example, DE 10 2014 109 055 A1 discloses a sliding door drive in which cable drums are driven by an electric motor via a gearbox and a clutch. The cable or winding drums are driven by a reversing drive motor via an intermediate gearbox. When the sliding door is closed, a cable strand connected to a door arm is wound onto a winding drum, and another cable strand connected to the support arm is unwound from another winding drum. The cable or winding drums are supported on one side by a bearing in the clutch gear unit.

[0004] DE 198 19 421 A1 discloses a sliding door drive for the sliding door of a motor vehicle, wherein the sliding door is connected to a cable pull unit by a door arm and the cable pull unit has at least one cable pull and at least one winding drum for winding and unwinding the cable. The winding drum is driven by a reversing drive motor via an intermediate gear unit, wherein, when the sliding door is closed, a cable strand connected to a door arm is wound onto the winding drum and another cable strand connected to the support arm is unwound from the winding drum. Furthermore, the drive motor and the gear unit are arranged on the inside of the vehicle body, wherein a cable guide is provided for the cable pull. When the sliding door is closed, a cable strand connected to the door arm is wound onto the winding drum and another cable strand connected to the support arm is unwound from the winding drum.The winding drum is designed as a single-piece drum. However, it is also possible to implement two coaxially mounted winding drums, which are spring-loaded in opposite winding directions to maintain rope tension.

[0005] US 4,640,050 B discloses a sliding door drive for a sliding door, in which the sliding door can be moved from a closed position to an open position or vice versa. The sliding door drive comprises a reversible motor attached to the underside of the vehicle floor plate, a speed reduction device, and an electromagnetic claw clutch mounted in this speed reduction device. A cable drum extending downwards beneath a housing is rotatably mounted on the lower part of the shaft. A rotor is connected to the top of the cable drum via a wedge connection such that it can move axially relative to the shaft but cannot rotate relative to the cable drum. The cable drum is rotatably mounted on a drive shaft, wherein the drive shaft is accommodated in a housing and a housing cover.What is disclosed is a double-sided bearing of a drive shaft, but the drive shaft itself in turn forms a bearing point for a ball bearing of the cable drum, so that a structurally complex solution is disclosed.

[0006] Shaft bearings with two bearing points are known from DE 10 2015 215 627 A1, EP 3 351 826 A1, US 2007 / 194600 A1 and US 2007 / 209382 A1.

[0007] The known state of the art provides solutions for supporting the cable drum of a sliding door drive, but overall, there is room for improvement. In particular, depending on the size of the driven sliding door, the forces acting on the cable drum can vary greatly, and / or environmental influences can affect the load on the cable drum. In any case, the cable drum must be able to provide the most uniform torque possible to operate the sliding door, and in extreme situations, it should be possible to provide a bearing for the cable drum shaft that is as free of play as possible and thus secure. This is where the invention comes in.

[0008] The object of the invention is to provide an improved sliding door drive for a motor vehicle. In particular, the object of the invention is to provide a sliding door drive for a motor vehicle that ensures play-free mounting of the cable drums, has a simple design, and can provide high long-term stability for the sliding door drive.

[0009] The object is achieved by the features of independent patent claim 1. Advantageous embodiments of the invention are specified in the subclaims. It should be noted that the exemplary embodiments described below are not limiting; rather, any possible variations of the features described in the description and the subclaims are possible.

[0010] According to claim 1, the object of the invention is achieved in that a sliding door drive for a motor vehicle is provided with a drive unit, comprising a housing, wherein the housing comprises a lower housing part, a middle housing part and a housing cover, an electric drive, a gear connected downstream of the drive, which is designed as a planetary gear and which comprises at least one ring gear, and a clutch, wherein at least one angle drum arranged on a shaft can be driven by means of the drive unit, wherein the shaft is mounted at least twice in the housing, in particular at the axial ends of the shaft in the housing, wherein the shaft is inserted into a receptacle of the ring gear, so that the shaft can be driven by means of the ring gear, wherein the ring gear is received in a plain bearing in the middle part of the housing, and wherein the receptacle of the ring gear is reinforced with a steel bushing.The inventive design of the sliding door drive makes it possible to provide a play-free bearing for the cable drums. In particular, the double bearing of the shaft in the housing makes it possible to guide the cable drums precisely and thus reliably ensure continuous drive by means of the cable drums even in extreme situations. For example, environmental influences such as frost can make the sliding door difficult to move, resulting in increased loads on the sliding drive. The load is transferred to the cable drum or winding drum via the cable arranged on the sliding door. The double bearing allows the cable drum to be securely positioned, ensuring that force is evenly applied to the sliding door and at the same time preventing the risk of the cable skipping in the winding groove of the cable drum.The design allows for a permanently stable and resilient drive system, as the double bearing of the shaft means that no or only very low tilting forces are introduced into the drive mechanism and, in particular, into the drive components downstream of the shaft. The loads exerted by the cable on the drive are evenly absorbed in the housing, so that the lowest possible loads are introduced into the gear components downstream of the shaft. The reinforcement element ensures high long-term stability of the sliding door drive. In particular, components of the sliding door drive, such as the winding shaft itself and the planetary gear carrier, can be made of plastic. Depending on the requirements of the sliding door drive, the components in the power flow of the sliding door drive can of course also be made of metallic materials such as brass, aluminum, or steel.

[0011] Preferably, the shaft is accommodated in the housing at its axial ends. Axial ends refer to at least the areas of the shaft that lie outside the mounting or bearing surfaces of the winding shaft(s). The bearing points for the winding shaft are thus spaced apart on the shaft and located on the opposite ends of the cable drum. The bearing points are preferably located at the axial ends or at least on one side of one axial end of the shaft and, as far as structurally possible, at the axial end.

[0012] The sliding door drive comprises a drive unit and preferably an electric motor, which can be used to introduce a corresponding output torque into the sliding door drive. The electric drive interacts with a gearbox to provide the appropriate gear ratios for the sliding door. The gear ratios can, of course, vary, as the sliding door drive can drive different door widths, weights, or heights. The gearbox adapts the drive torque and / or the speed of the electric drive to the closing speed.

[0013] To further adapt to the closing speed, the diameter of the cable drum can be varied, which in turn influences the forces available when moving the sliding door.

[0014] The sliding door drive further comprises a clutch, allowing the drive to be decoupled from the winding drum shaft. This decoupling of the drive is necessary to enable emergency operation of the sliding door. Generally, the electric drive has a braking torque that can prevent or at least severely restrict movement of the sliding door, particularly in combination with the gear mechanism. To ensure that the sliding door can be moved manually and easily, for example, in the event of a power failure, the clutch can be used to interrupt the drive chain, allowing the sliding door to be moved manually. Embodiments of the clutch are known, for example, from the cited prior art.

[0015] According to the invention, the housing is constructed in three parts. A multi-part structuring of the housing enables easy assembly of the sliding door drive and, at the same time, it is possible to provide bearing points at preferred locations on the shaft or winding shaft, which enable defined support of the shaft arranged at preferred bearing points. A gearwheel, with which the drive motor meshes, is rotatably mounted in a lower gear section. In addition, the lower gear section supports the gear unit and the coupling. The gear unit center section, on the one hand, supports the gear unit and, at the same time, provides a first bearing point for the shaft of the cable drums. The housing can be closed using a gear unit cover, whereby the housing cover also provides an additional bearing point for the winding shaft.

[0016] If at least one bearing point of the shaft is arranged in a housing cover, a preferred embodiment of the invention is achieved. The gear cover accommodates an outer axial end of the shaft and contains a bearing point for the shaft. The cable drums or winding drums are held directly on the shaft in a form-fitting and / or force-fitting manner. If the shaft is rotatably mounted in the central gear section, an additional axially spaced-apart bearing for the shaft can be provided by means of the housing cover. The bearing point in the housing cover is arranged at an axial end of the shaft, so that the most favorable bearing point possible can be provided for absorbing torques from the pull cables of the door drive.The shaft is supported by the bearing in the housing cover at the outer axial end, which ensures safe and stable support of the shaft even in extreme situations where large tensile forces occur in the cables of the sliding door drive.

[0017] If two winding drums are arranged on the shaft or winding shaft, this results in a further embodiment of the invention. In this preferred embodiment, a winding shaft is connected to a support arm of a sliding door, so that the sliding door can be closed, for example, by means of this first winding drum. The second winding drum has a cable which is connected on the one hand to the winding drum and on the other hand also to the support arm of the sliding door, wherein the cable is guided in the body of the motor vehicle in such a way that the sliding door can be pushed or opened by means of this second cable. The cables of the first and second winding drum therefore act in different directions with respect to the sliding door. For example, if the sliding door is closed by means of the first cable, whereby the cable is wound up on the first winding drum, the second cable is unwound on the second winding drum.To ensure that the first and second winding drums are securely held on the shaft, the winding drums can be secured to the shaft by means of a spring element, and in particular by means of a single spring element. For example, the winding drums can be mounted on the shaft by means of a tongue and groove connection.

[0018] However, it can also be advantageous and form a further embodiment of the invention if the shaft is made of plastic, wherein the shaft is provided with at least one metallic core. A plastic shaft offers the advantage of being lightweight and easy to form, thus enabling a structurally favorable design and easy assembly. The additional metallic reinforcement of the plastic shaft can combine the advantages of being lightweight with sufficient stability to transmit the required torque. In particular, the metallic core can extend through the shaft in some areas and preferably into an area of the gearbox that accommodates the shaft.

[0019] A further embodiment of the invention results when the shaft is mounted in plain bearings in the housing. Plain bearings offer a structurally advantageous option for achieving high long-term stability and, at the same time, are extremely small in size. Furthermore, they are advantageously very small and cost-effective. Preferably, the shaft is mounted at one axial end in the housing cover by means of a plain bearing and is rotatably held in a plain bearing in the housing center section. The design of the sliding door drive according to the invention ensures play-free mounting of the cable drums even under the highest loads, while simultaneously ensuring a structurally advantageous design and high long-term stability.

[0020] The invention will be explained in more detail below with reference to a preferred embodiment and the accompanying drawings. However, the principle applies that this embodiment does not limit the invention, but merely represents one embodiment of the invention.

[0021] It shows: Fig. 1 shows a section through a sliding door drive constructed according to the invention, the section being shown as a cross section through a longitudinal axis of the shaft of the winding drums.

[0022] In the Figure 11 shows a sliding door drive 1 in a cross-sectional view. In this embodiment, the sliding door drive 1 has a three-part housing 2, wherein the housing 2 is divided into a lower housing part 3, a middle part 4, and a housing cover 5. A drive motor (not shown) can be inserted through an opening 6 in the lower part 3 and connected to the housing 2. The drive motor engages a worm gear 7, for example, with a worm arranged on an output shaft. In this exemplary embodiment, the worm gear 7 is designed with an injection-molded gear 8 as a sun gear for a downstream planetary gear 9. The power of the drive motor can be transmitted to a shaft 11 by means of the ring gear 10 of the planetary gear 9. For this purpose, the shaft 11 can be inserted into a receiving opening 12 in the ring gear 10 and can be connected to the shaft 11 in a form-fitting and / or force-fitting manner.The shaft 11, in turn, is rotatably mounted in the housing center section 4 and in the housing cover 5. For this purpose, in this embodiment, plain bearings 13, 14 are arranged in the housing cover 5 and in the housing center section 4. The shaft 11 is thus guided at its axial ends in the housing 2, preventing tilting of the shafts 11 in the sliding door drive 1.

[0023] In this embodiment, two cable or winding drums 15, 16 are arranged on the shaft 11. The winding drums 15, 16 are positively and / or non-positively connected to the shaft 11 and connected to each other by a spring element 17. The winding drums 15, 16 each serve to accommodate cables (not shown) for driving a sliding door. The cables of the winding drums 15, 16 are attached to different ends of the sliding door, so that the sliding door can be moved in different directions depending on the direction of rotation of the drive motor.

[0024] The shaft 11 is preferably designed as a hollow shaft, but can be supported by a steel core. This is particularly advantageous if the shaft is made of a plastic. Depending on the design and requirements of the sliding door drive 1, the shaft 11 can be made as a plastic component or from a metallic material. In this exemplary embodiment, the shaft 11 can be inserted into a receptacle 12 of the ring gear 10, so that the shaft 11 can be driven by the ring gear 10. The ring gear 10 is also received in a plain bearing 19 in the housing center section 4. In addition, the receptacle 12 can be reinforced with a steel bushing 20. By reinforcing the receptacle and / or the shaft 11, a safe, tilt-free, and stable drive system for the sliding door can be provided.The plain bearings 13, 14, 19 for the ring gear 10 and the shaft 11 stabilize the winding drums 15, 16 in the housing 2, so that the sliding door can be driven with the least possible play and / or drive losses.

[0025] To enable emergency operation of the sliding door drive 1, a clutch 21 is additionally arranged between the worm gear 7 and the shaft 11. If the clutch 21 is actuated against the force of a circumferentially arranged spiral spring (not shown), whereby a sliding element of the clutch 21 is displaced in the direction of arrow P1, the power transmission between the worm gear 7 and the shaft 11 is interrupted, thereby enabling and / or at least facilitating manual movement of the sliding door. List of reference symbols

[0026] 1 Sliding door drive 2 Housing 3 Housing base 4 Housing center 5 Housing cover 6 Opening 7 Worm gear 8 Gear, sun gear 9 Planetary gear, epicyclic gear 10 Ring gear 11 Shaft 12 Mount 13, 14, 19 Plain bearing 15, 16 Winding drum 17 Spring element 18 Steel core 20 Bushing 21 Coupling P1Arrow AAxis

Claims

1. Sliding door drive (1) for a motor vehicle, comprising a drive unit having a housing (2), wherein the housing (2) has a housing lower part (3), a housing center part (4) and a housing cover (5), and having an electric drive, a transmission (9) connected downstream of the drive and a coupling (21), wherein at least one winding drum (15, 16) arranged on a shaft (11) can be driven by means of the drive unit, wherein the shaft (11) is mounted at least twice in the housing (2), in particular at the axial ends of the shaft (11), wherein axial ends refer to the regions of the shaft that are outside the receptacle or bearing surfaces of the winding shaft,characterized in that the transmission is designed as a planetary transmission which has at least one ring gear (10), wherein the shaft (11) is inserted into a receptacle (12) of the ring gear (10) so that the shaft (11) can be driven by means of the ring gear (10), wherein the ring gear (10) is received in a plain bearing (19) in the housing center part (4), and wherein the receptacle (12) of the ring gear (10) is reinforced with a steel bushing (20).

2. Sliding door drive according to claim 1 characterized in that at least one bearing point (13, 14) of the shaft (11) is arranged in a housing cover (14).

3. Sliding door drive (1) according to either of claims 1 to 2, characterized in that two winding drums (15, 16) are arranged on the shaft (11).

4. Sliding door drive according to claim 3, characterized in that the winding drums (15, 16) are connected to one another and / or to the shaft (11) for conjoint rotation by means of a spring element (17).

5. Sliding door drive (1) according to any of claims 1 to 4, characterized in that the shaft (11) is made of plastics material, wherein the shaft (11) is provided with at least one metal core (18).

6. Sliding door drive (1) according to claim 5, characterized in that the metal core (18) extends axially, at least in regions, into the region of the receptacle (12).

7. Sliding door drive (1) according to any of claims 1 to 6, characterized in that the shaft (11) is mounted in plain bearings (13, 14) in the housing (2, 3, 4, 5).