DK178043B1 - Motor driven linear drive - Google Patents

Abstract

A motor-driven linear drive, in particular a dual drive with two drive units for displacing a furniture component each, and with a housing (14), a drive motor (10), a motor speed reducing gear, a spindle mounted by a bearing (16) (12), where the gear unit is held to functionally match by means of a fixing device (17), must be designed in such a way that both the design of the fixing device (17) can be integrated integrally with the housing and the use of screws or similar connecting elements where the gear unit must be maintained accurately and inexpensively. According to the invention, the fixing device (17) is designed as a molding piece which is at least partially inserted mold and / or force-locking in the housing accommodating housing (15). Provided from the bearing seat of the bearing (16) for bearing the spindle (12), a flange is provided for holding the drive motor (10) on the molding piece (17). The designated linear drive is particularly suitable for a slat base.

Description

BACKGROUND OF THE INVENTION The invention relates to a motor driven linear drive, in particular a dual drive with two drive units for displacing a furniture component each, and having a box-like housing, which is provided with parallel and spaced side walls and is closed by means of an attached lid to which the housing is provided. with flush recesses in which one shaft rotatable by the respective drive unit can be inserted into a furniture, and the impact surface between the housing and the lid extends parallel to and displaced from the longitudinal axis of the shaft and parallel to a spindle in the respective drive unit and each drive unit is provided with a drive motor in such a way that the recesses are located between the drive motors and where each drive motor is coupled to a motor speed reducing gear to drive it by means of a bearing spindle, and which is maintained functionally by means of a fixing device. The fixing device is designed as a molding piece which is at least partially inserted molding and / or force locking in the housing chamber where the gear is accommodated.

The present motor-driven linear drive is in normal embodiment a dual drive equipped with two drive motors. With the aid of each drive motor, the gear which is usually a worm gear is driven. The worm in these worm gears is pivotally attached to the drive motor drive pin, or the drive pin is designed as a worm. The worm-engaging worm wheel is pivotally connected to the spindle. Bearing of the spindle and thus also the worm wheel is effected by means of a roller bearing, which is placed next to the worm. The housing is designed as a box and is mounted in reverse as the lid is at the bottom, respectively, and the flushing recesses for receiving the shafts occur in the side walls at the lid opposite edges. This design causes the impact surface between the housing and the lid to remain in relation to the longitudinal axis of the shafts and parallel to and spaced from the spindles. Normally, however, the impact surface is within the range over which the spindles extend.

In a known linear drive for fixing each gear, a so-called gear angle is inserted into the housing and screwed onto the housing wall. However, this good solution in itself is relatively time-consuming to install due to the tightening of the screws. It is therefore proposed to integrate the fixing device integrally with the housing. This eliminates the screws, but the gear cannot be positioned precisely because of the inevitable manufacturing tolerances. In addition, it is inevitable that the housing is deformed elastically by a load, and this deformation acts negatively on the gear, as, for example, the axis distance between the worm and worm wheels is changed.

In another known linear drive, gear motors are used. Thereby the gear consists of a multi-part gearbox, a separate bearing for the gear wheel and the gear wheels. The gear is permanently connected to the engine and forms a unit with it. Due to the many components and additional manufacturing and assembly costs, such a gear motor is cost-heavy. As the linear drives in question are mass articles, reduced costs are needed.

DE 202004000950 U1 discloses a motor-driven linear drive with a box-like housing provided with parallel and spaced side walls. The housing is closed by means of an attached lid, and the housing is provided with flush recesses. In the recesses, a shaft rotatable by the drive unit can be inserted into a piece of furniture, and the impact surface between the housing and the lid extends parallel to and displaced from the longitudinal axis of the shaft and parallel to a spindle. The drive unit is provided with a spindle motor, which is coupled to a reducing gear, which reduces the engine speed to drive a spindle which is mounted in bearings. The spindle is held by means of a fixing device and is kept functionally compliant.

The object of the invention is to provide a motor-driven linear drive of the type initially indicated, avoiding both the integral design of the fixing device and the use of screws or similar connecting elements and in addition obtaining an accurate and cheap fixation of the gear.

This is achieved according to the invention in that the linear drive is designed as a double drive for movement of the backrest and footing in a slat base, and that the housing at the spindle nuts exhibits two flush recesses in which the shaft s are arranged.

The motor-driven linear drive is thus designed as a double drive for movement of backrests and feet in a slatted floor, sun lounger, armchair or the like. As already mentioned, at each end region the housing is provided with two flush recesses intended for receiving a shift shaft in each housing.

As mentioned above, the fixing device is designed as a molding which is at least partially inserted molding and / or force locking into the gear housing receiving chamber.

The housing of a linear drive of the kind in question is usually made of plastic. The molding can also be made of plastic and within certain limits be elastically deformable. In this way, tolerances in individual chambers can easily be offset. The same goes for the gear components. The molding therefore fulfills a dual function, that is, at least to fix the gear and to offset inevitable tolerances and deformations. Conveniently, a flange is provided for holding the drive motor on the molding from the bearing seat of the bearing to bearing the spindle. The motor can then be plugged or screwed onto the die. The molding thus further has the task not only of fixing the bearing for the spindle but also of holding the motor in order to determine the axle spacing of the gear wheels.

Since the driven gear wheel, for example the worm wheel, is firmly connected to the spindle, a sub-group consisting of the motor with attached or shaped worm, the molding, the spindle bearing, the spindle and the worm wheel is advantageously obtained. Such a subassembly may be manufactured independently of the mounting of the linear drive to be disposed in the housing upon completion of the linear drive. In this way, as already described, the molding is inserted with the mounted components in the relevant housing chamber. Parts of the group thus form the gear.

As the dimensions of the piece compared to the linear drive housing are relatively small, very narrow tolerances on the wheelbase between the gear wheels are possible, so that optimum operating safety is achieved in the gear. Thus, a worm and a worm wheel are preferably used as gear wheels.

It is convenient that the molding is potted and has a bearing seat for the spindle holding bearing. The outer surface of this part of the molding is adapted to the housing chamber and is sealed closed therein. Since the shape piece compared to the motor driven linear drive housing has relatively small mass and dimensions, the shrinkage dimension is also correspondingly small, so that the bearing seat is extremely thin.

It is convenient that the molding consists of a material of greater strength than the material of the housing. For this purpose, reinforced plastics, such as fiber-reinforced plastics, as well as metallic materials such as zinc or aluminum are offered.

For linear drives of the type in question, relatively large forces are transferred to the housing. It is therefore advantageous that the housing in the areas of the linear drive where relatively large shear forces via the bearing are diverted to the housing exhibits moldings, ribs or walls which are significantly thicker than the other housing sections.

Particularly advantageous is the use of a relatively small component with greater strength in all areas of the linear drive, where the large shear forces are intercepted via the bearing. These locally highly concentrated forces can then be distributed over a larger surface to the linear drive housing, so that the rest of the housing can be made of less strength material, reducing the cost. Plastic, for example, comes up as a material.

It is convenient that the molding member on the open side facing away from the bearing seat has a worm wheel at least partially engaging support section. This precisely fixes the gear. It is advantageous that the support section is bowl-shaped, which gives an exact fixation of the worm wheel. It is then particularly advantageous that the area of the worm wheel circumscribed by the mold section of the piece constitutes at least 180 °.

The movable furniture part is then connected to the shaft by means of a still arm. To facilitate mounting, the housing at the ends exhibits guides for a recessive bolt bolt. The guides run parallel and spaced apart and may extend in the longitudinal direction of the spindle or across the spindle. On each spindle is mounted a spindle nut, which is secured against rotation and therefore when turning the spindle is moved longitudinally. In a first embodiment, the spindle nut lies between the recesses of the housing for receiving the shaft and the gear. The surface turned from the gear on the spindle nut is connected to a guide arm which is firmly connected to the shaft. As the spindle nut moves away from the gear, the connected furniture component is displaced, for example, against the influence of gravity. In such a design, the spindle is then loaded with compressive forces, which is why such a linear drive is referred to as a pressure drive. In another embodiment, the recesses for the shaft lie between the spindle nut and the gear. The articulated arm attached to the shaft is then in contact with the sides facing the gear nut. When the furniture part is displaced, for example against the effect of gravity, the spindle is then tensile loaded, which is why such a linear drive is referred to as a tensile drive.

The respective furniture part is displaced in a given direction by driving the motor in the corresponding direction of rotation. Thereby, displacement can be effected by motor force against the effect of gravity, while displacement of the furniture part in the other direction occurs under the effect of gravity.

The walls of the house are most stressed by the recesses of the shaft. Therefore, it is desirable that the walls of the housing at least in areas adjacent to the recesses of the shaft are formed with several walls, preferably double walled. Thereby the individual walls can stand and be interconnected by means of ribs or moldings.

It is particularly advantageous that the sidewalls of the housing are formed substantially without interruptions and substantially rectilinear in the longitudinal direction of the housing so that they are at least in the region between the recesses for the shafts. This gives the house a high stiffness and therefore a correspondingly high resistance to deflection. It is particularly advantageous when the multi-walled housing portions of the recesses are designed so that either the inner or outer surface protrudes inwards or outwards. For example, in a multi-walled housing section, a symmetrical design is proposed, with the inner wall projecting inwards and the outer wall projecting outwards.

The linear drive housing may be a two-piece housing. It then consists of a box-shaped housing part with a fixed base and with the recesses for receiving the shafts for moving the connected furniture parts at the housing base. The other housing part is a lid in one or more parts and extends the entire length of the box-shaped housing. The parts of the housing are connected to each other by a suitable joining method, for example by means of screw joints, adhesive joints or welding joints, and may further have interlocking sections to thereby achieve a mutual locking.

The stiffness of the housing increases if the motors are placed at the ends of the housing so that the recesses for the shafts are located between the motors.

Each drive spindle is usually made of steel, while the spindle nut is made of plastic. The worm is also made of steel, while the worm which is thus engaging is also made of plastic. Especially in pressure drives, it is convenient to produce the spindle and worm wheel of a plastic mold part of a first plastic material, while the spindle nut consists of a second plastic material.

In the case of linear drives of the type in question, the housing parts or the housing part and the lid may be formed differently. However, in a preferred embodiment, the longitudinal axis of each spindle lies in the plane of the impact surface between the housing and the lid.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be explained in more detail in connection with the drawing, in which 1 shows a part of a motor driven linear drive, namely a drive assembly arranged in a housing half, and FIG. 2 shows a variant of the embodiment of FIG. 1.

The 1 and 2 drive linear drives are designed as dual drives. For the sake of simplicity, both figures show only a power unit mounted in a housing half or a housing shell. The second drive unit is located as a mirror image to the right of the screen shown.

The FIG. 1 in a dual drive comprises an unspecified electric drive motor 10, on which the drive pin is pivotally attached to a worm or where the drive pin is designed as a worm. The worm engages with a worm wheel 11. The worm wheel 11 and the worm form the engine speed reducing gear. In a concentric bore in the worm wheel 11, a spindle 12 is permanently inserted on this spindle 12 is a spindle nut 13 secured against rotation, which, when turning the spindle 12, moves in its longitudinal direction depending on the direction of rotation. The housing 14 consists of two halves made of plastic. The housing 14 contains a drive motor 10 associated with housing chamber 15 in which not only the worm wheel 11 is arranged, but also on the side facing the spindle nut 13 a roller bearing 16 for bearing the spindle 12. For fixing the roller bearing 16 and the worm wheel 11, there is inserted in the housing chamber 15 a fixing device in the form of a molding piece 17. This molding piece 17 is made of plastic and is designed so that it can be inserted molding and / or force-locking into the housing chamber 15. This housing chamber 15 can also be called a driving chamber. Furthermore, it is designed so that the gears formed by the worm and worm wheel 11 are precisely fixed. It further contains the roller bearing 16. For this, the molding piece 17 is potted and on the side facing the spindle nut 13 is provided with a bearing seat for the roller bearing 16. The area facing the worm wheel 11 has a slightly larger diameter, so that the worm wheel 11 can rotate freely. The shape-stable molding 17 also compensates for the tolerances of the housing 14 as the housing is deformed by a load.

The FIG. 1 linear drive is designed as a pressure drive. For the sake of simplification, the recesses, which are interchangeable to a shaft in the housing walls, are not shown. The spindle nut 13 cooperates on the side facing away from the worm wheel 11 with a non-shown connecting arm attached to the shaft pivotally.

FIG. 2 shows the linear drive as a pull drive. In the housing walls are the escape recesses for the shaft 18. The face of the worm wheel 11 on the spindle nut 13 cooperates with a connecting arm 19 which has a U-shaped cross section. It can be seen from FIG. 2, the spindle 12 is tensioned as the spindle nut 13 moves in the direction of the worm wheel 11.

Neither in FIG. 2, the recesses for the shaft 18 are shown. They are located in FIG. 2 below the drawing plane and accommodates shaft 18 in a switching device for a furniture component, also not shown. For simplicity's sake, the bolts are not shown either. They extend under the shaft 18.

In FIG. 2, the separating plane of the housing parts, which lies in the drawing plane, is recognized parallel to the longitudinal axis of the shaft 18. For simplified viewing, the cover of the housing 14 is removed so that the interior of the linear drive is visible. Furthermore, the longitudinal axis of the spindle 12 and the worm wheel 11 lie in the drawing plane. Therefore, the lid of the housing 14 not shown in FIG. 2 on the drawing board.

The housing 14 is designed as a box and is provided with a bottom which lies below the longitudinal axis of the shaft 18 in FIG. 2. The sidewalls 22 of the housing 14 exhibit substantially continuous moldings extending over nearly the entire length of the housing 14 or at least extending past the recesses of the shaft 18.

At the recesses of the housing 14 for receiving the shaft 18, multi-walled housing sections 20,21 are provided to ensure optimum support and bearing of the shaft 18 in the housing 14. Thus, the housing sections 20,21 extend outwardly while a molding 22 is formed as a continuous sidewall 22 in the housing. and preferably extending over the entire length of the linear drive parallel to another side wall 22.

FIG. 2 also shows a housing area 23 which is reinforced by material increase as the abutment wall in the housing chamber 15, where the molding 17 is located. Thereby, the molding 17 takes up substantial parts of the drive such as, for example, the worm wheel 11, the roller bearing 16 and a worm shaft not shown, from the electric drive motor 10. The molding transfers the forces via the reinforced housing area 23 to the housing 14 and directs them to the side walls 22 of the housing 14.

Furthermore, the drive motor 10 is not attached to the molding piece 17 in a specific manner.

The spindle nut 13 is spaced from the shaft 18. By force acting on the spindle nut 13 on the connecting arm 19, the shaft 18 is imparted a torque and makes a pivotal movement about its longitudinal axis.

In the illustrated embodiments, the mold piece 17 is disposed exclusively in the housing chamber 15, where also the worm, the worm impeller 11 and the roller bed 16 are also arranged.

Contrary to the shown, the molding 17 could extend only partially into the housing chamber 15 where said components are arranged.

The invention is not limited to the embodiments shown. It is essential that in the gear receiving housing chamber 15 is inserted a molding device 17 forming a fixing device, which, in addition to fixing the gear, also serves to fix the roller bed 16 for mounting the spindle 12.

reference numeral 10 electric drive motor II worm wheels 12 spindle 13 spindle nut 14 housing 15 housing chamber 16 roller bearing 17 molding 18 shaft 19 connecting arm 20,21 housing section 22 sidewall, list 23 reinforced housing area

Claims (20)

A motor-driven linear drive, in particular a dual drive with two drive units for displacing a furniture component each, and with a box-like housing (14) provided with parallel and spaced-apart side walls (22) and closed by means of an attached lid , wherein the housing (14) is provided with flush recesses in which a shaft (18) pivotal of the respective drive can be inserted into a furniture, and the impact surface between the housing (14) and the lid extends parallel to and displaced from the shaft (18). longitudinal axis and parallel to a spindle (12) in the respective drive unit, and each drive unit being provided with a drive motor (10) in such a way that the recesses are located between the drive motors (10) and each drive motor (10) is coupled to a drive motor (10). the speed of the motor reducing gear to drive the spindle (12) stored by a bearing (16), and which is held in accordance with a fixing device (17) and which the fixing device is designed so m a molding piece (17) which is at least partially inserted molding and / or force-locking in the housing chamber (15) accommodated by the gear (11), characterized in that the linear drive is designed as a double drive for movement of the backrest and foot in a and the housing (14) at the spindle nuts (13) exhibits two flush recesses in which the switching shafts are arranged. Linear drive according to claim 1, characterized in that a flange for holding the drive motor (10) on the molding piece (17) is provided from the bearing seat of the bearing (16) for bearing the spindle (12). Linear drive according to claim 1 or 2, characterized in that a sub-unit is formed by the electric drive motor (10) with attached or shaped worm, the mold (17), the bearing (16) for the spindle (12) and the worm wheel (11). . Linear drive according to claim 1, characterized in that the molding (17) is potted and has a bearing seat for the bearing (16) holding the spindle (12). Linear drive according to claims 1-4, characterized in that the mold piece (17) consists of a material of greater strength than the material of the housing (14). Linear drive according to claims 1-5, characterized in that the housing (14) in the areas of the linear drive where relatively large shear forces are applied via the bearing (16) to the housing, exhibits strips, ribs or walls which are significantly thicker than the other housing section. Linear drive according to claim 2, characterized in that the mold piece (17) on the open side facing away from the bearing seat has a worm wheel (11) at least partially engaging support section. Linear drive according to claim 7, characterized in that the support section is annular or bowl-shaped. Linear drive according to claim 8, characterized in that the area of the worm wheel (11) enclosed by the support portion (17) of the molding piece (17) is at least 180 °. Linear drive according to claim 1, characterized in that the flush recesses in the housing (14) are provided in guiding bolts. Linear drive according to claim 10, characterized in that the guides extend in parallel and at a distance between them and that the guides extend in the longitudinal direction of the spindle or across the spindle (12). Linear drive according to claims 1-11, characterized in that a spindle nut (13) is secured to each spindle (12). Linear drive according to claim 12, characterized in that the spindle nut (13) is arranged in the region between the recesses of the housing (14) and the bearing (16). Linear drive according to claim 13, characterized in that the recesses for the shaft (18) are located between spindle nut (13) and housing chamber (15). Linear drive according to claims 1-14, characterized in that the walls (14) of the housing (14) are formed, at least in areas adjacent to the recesses of the shaft (18), with multiple walls, preferably double-walled. Linear drive according to claim 15, characterized in that the individual protruding walls of the housing (14) are interconnected by means of ribs or strips. Linear drive according to claims 1-16, characterized in that the sidewalls of the housing are formed substantially without interruptions and substantially rectilinear in the longitudinal direction of the housing (14), and that the individual protruding walls at the recesses project outwards and / or inwards. Linear drive according to claim 17, characterized in that the walls (14) of the housing (14) are at least formed by the recesses symmetrically in such a way that the inner wall projects inwards and the outer wall projects outwards. Linear drive according to claims 1-18, characterized in that the parts of the housing (14) are connected to each other by a suitable joining method, for example by means of screw connections, adhesive connections, welding joints and the like, and that parts of the housing (14) have optionally interrelated sections. Linear drive according to claims 1-19, characterized in that the longitudinal axis of the spindle (12) lies in the plane of the impact surface between the housing (14) and the lid.