EP2297839A2

EP2297839A2 - Transmission drive unit having a self-locking device

Info

Publication number: EP2297839A2
Application number: EP09772350A
Authority: EP
Inventors: Tarek Mili; Detlef Lauk; Uwe Merkelbach
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-07-04
Filing date: 2009-06-23
Publication date: 2011-03-23
Also published as: US8823228B2; KR20110040813A; KR101648020B1; JP2011526777A; DE102008043173A1; WO2010000650A2; CN102144348A; WO2010000650A3; JP5570505B2; US20110221291A1; CN102144348B

Abstract

Transmission drive unit (10), in particular for adjusting movable parts in the motor vehicle, having a drive motor (12) and a transmission (14) which is driven thereby, wherein the transmission (14) has an output element (70) and a self-locking device (60) with a locking element (63, 55), and the locking element locks the transmission (12) with respect to torques which are applied to the transmission (12) by the output element (70), wherein the transmission (12) with its transmission toothing (47) and a motor shaft bearing (32, 28) is designed to have optimized efficiency and minimal friction, and the drive motor (12) has, as an exciter magnet, a sleeve-shaped annular magnet (18) which is arranged in a pole pot (16) which forms a magnetic return.

Description

description

title

Transmission drive unit with a self-locking device

State of the art

The invention relates to a transmission drive unit with a self-locking device, in particular for adjusting moving parts in the motor vehicle according to the preamble of the independent claim.

With DE 197 53 106 C2 a load torque lock has become known, which is installed in a drive train and automatically locks the torque introduced by the output at standstill of the drive. In contrast, the torques introduced by the drive side are transmitted in both directions of rotation. This will be a

Drive shaft penetrated by the attachments of an output shaft. Between these two mutually rotatable shafts radial webs, as well as clamping or locking elements are arranged which allow or block a rotation relative to a clamping ring unit in dependence on the drive-side or driven-side introduction of the torques. Such a load torque lock consists of a variety of items that are expensive to assemble and take up much space. As a result, the gear drive unit is relatively large and heavy, whereby a correspondingly powerful electric motor for driving is required.

Disclosure of the invention

Advantage of the invention The transmission drive unit according to the invention with a self-locking device with the characterizing features of independent claim 1 has the advantage that at the same time a drive motor with a lower weight can be used by the cost-effective design of a transmission with reduced friction for the same applications. For this purpose, the excitation magnet of the electric motor is designed as a relatively small and lightweight ring magnet, which encloses the armature package with the winding coils. The fact that the load torque lock is formed by a separate self-locking device, an efficiency-optimized transmission can also be used for actuators, in which the transmission is to be locked at a power take-off load, as for example in

Window lift, sunroof, wiper or seat drives is required.

The measures listed in the dependent claims advantageous refinements and improvements of the dependent claim device are possible. Thus, the power density of the drive motor can be increased by the fact that the permanent-magnet of the electric motor can also have more than two magnetic poles. Preferably, an even number of magnetic poles is used, for example 2, 4, 6 or 8 magnetic poles, wherein in the formation of exactly 4 magnetic poles, an optimum compromise between the increase in power density and the magnetization of the ring magnet for these engine sizes is achieved.

It is particularly advantageous to form the wall thickness of the ring magnet between 0.5 mm and 3 mm, with a comparatively small wall thickness of 0.5 mm to 1.5 mm - e.g. Approximately 1.0 mm - a particularly favorable

Power density of the electric motor can be achieved. For the weight reduction of the overall drive, it is particularly advantageous if the relation between the outer diameter of the ring magnet and its wall thickness is approximately between 15: 1 and 40: 1.

Expediently, a high-energy magnetic material is used for the production of such an annular magnet, preferably side-earth elements. This material can be particularly cost by sintering or in a Plastic bound to be shaped into an annular magnet. NdFeB is a particularly preferred high-energy magnetic material.

It is advantageous to arrange the ring magnet in a circular pole pot, which is preferably produced by deep drawing. In this case, the outer diameter of the pole pot, for example, between 25 mm and 33 mm and the wall thickness is approximately between 1 mm to 2 mm, which is sufficient for the magnetic return. Preferably, the wall thickness of the pole pot in the cylindrical region is approximately 1.5 mm thick.

In order to increase the power density of the electric motor, the lamellae of the anchor package are made of a high-quality ferrous material and in particular of a thinner lamellar plate (compared with commercially available standard lamellae), so that in conjunction with the thin-walled ring magnet, the efficiency of the electric motor is significantly increased.

If the transmission of the gear drive unit designed as a worm gear, the teeth between the arranged on the drive shaft screw and the corresponding worm wheel can be performed with particular low friction. For this purpose, the worm toothing has a reduced pressure angle of, for example

4 ° to 8 ° and the surfaces of the teeth can be performed with a low friction coefficient (friction = 0.025) particularly optimized efficiency. For this purpose, an efficiency-optimized lubricant, e.g. Topaz L32 can be used.

In order to minimize the friction of the gear drive unit, the drive shaft is mounted on the one hand with a ball bearing, which is directly in the gear housing, preferably in an axial cylindrical extension thereof, arranged. In the pole pot, preferably at its bottom surface, the drive shaft, however, is mounted by means of a sliding bearing, which is preferably formed of sintered bronze.

In this case, the ball bearing can absorb all acting axial forces of the drive shaft, so that the slide bearing is designed as a movable bearing in the pole housing, whereby the friction of the transmission drive unit is additionally reduced. The screw is manufactured particularly favorable by means of a rolling or rolling process directly on the drive shaft by means of plastic material forming formed. The outer diameter of the screw is significantly larger than the diameter of the drive shaft in the areas adjacent to the screw. For this method, a diameter of the drive shaft of about 5 to 8 mm is particularly suitable, wherein a 6 mm shaft is particularly preferably used. The drive shaft in the region of the screw can preferably be formed integrally with the armature shaft in the region of the disk set - in an alternative embodiment, however, also as separate components, which are then connected, for example, by means of a coupling.

For storage of the worm wheel, a bearing dome is formed in the bottom surface of the gear housing, which engages in the hub of the worm wheel. The bearing dome is for example made in one piece with the gear housing bottom made of plastic. Alternatively, a bearing pin made of a different material (e.g.

Metal) to receive the worm wheel be arranged in the transmission housing.

For energizing the electric motor, the carbon brushes are advantageously designed as hammer brushes whose spring straps extend in the axial direction along the drive shaft. Particularly favorable is an arrangement of two

Carbon brushes, which are arranged offset in the circumferential direction by 90 °. In this case, the brush holder is annular, and inserted within an annular extension of the transmission housing.

Since the entire force acting on the drive shaft axial forces are absorbed by the ball bearing, which is arranged in the transmission housing, acting at the interface between the pole pot and the gear housing no large tensile forces. Therefore, the pole pot can advantageously be reliably connected to each other by means of a positive connection, for example by caulking or other material deformation. For this purpose, the pole pot is advantageous on the cylindrical outer wall of the

Gear housing extension arranged. Between the pole pot and the gear housing, an O-ring is for example arranged as a seal which is also pushed onto the cylindrical extension of the gear housing. The self-locking device has a locking element in a preferred embodiment, a wrap spring, which is inserted in between the worm wheel and the driver. In this case, a brake drum of the spring in the gear housing or in the lid or in a separate component is added.

Particularly space-saving, the wrap is doing radially on the gear housing, and engages without the use of additional separate components on the one hand in the worm and on the other hand in the driver, or the output element.

The self-locking device with the blocking element can also be integrated in the adjustment system of the movable part, for example as part of seat elements or a window regulator mechanism. In this case, the transmission can be arranged directly on the drive motor and / or in the adjustment system. In this case, the drive motor and / or at least a part of the transmission is always designed optimized efficiency. Preferably, the drive motor is formed together with at least part of the transmission as an integrated, compact unit that forms a defined interface to the part to be adjusted, or its adjustment system. The self-locking device is advantageously arranged in the separable (zulieferbaren) drive motor gear unit, but can also be arranged in the part to be adjusted or in the adjustment system. In any case, the load moment acting on the transmission drive unit by the movable part is favorably blocked effectively.

Brief description of the drawings

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

Show it

Figure 1 is an exploded view of a transmission drive unit according to the invention, Figure 2 shows a cross section through the pole housing, and Figure 3 shows another embodiment with a wrap spring as a self-locking device. FIG. 1 shows a transmission drive unit 10, which has a drive motor 12 and a transmission 14. The drive motor 12 has a pole housing 16 as a motor housing 15, in which a ring magnet 18 is arranged as the exciter magnet. The ring magnet 18 is formed in the embodiment as Hochenergiepermanentmagnet containing as rare earth material Nd FnB. Within the ring magnet 18, a lamination stack 20 is arranged with a plurality of fins 21 which is mounted on a drive shaft 22. The disk pack 20 has an electrical winding 24 which is connected to a commutator 26. The drive shaft 22 is mounted in the pole pot 16 by means of a sliding bearing 28, which here as

Sinter bronze socket 29 is formed. The sliding bearing 28 is designed as a floating bearing, whereby the drive shaft 22 in the sliding bearing 28 in the axial direction 23 is displaceable. Approximately in a central region of the drive shaft 22, a ball bearing 32 is arranged, which is fixedly fixed in the transmission housing 36 after the finished assembly. The ball bearing 32 is fixed with an inner ring 33 on the drive shaft 22, and with an outer ring 34 in the gear housing 36. As a result, the ball bearing 32 is designed as a fixed bearing, which receives all forces acting axially on the drive shaft 22 forces. The free end 30 of the drive shaft 22 protrudes through a cylindrical extension 38 of the transmission housing 36 and into the transmission housing 36. She makes no stop at it. On the drive shaft 22 is in the range of

Gear housing 36 a worm 40 is arranged. The screw 40 is formed, for example by means of plastic material deformation directly from the drive shaft 22, preferably by means of rolling. The outer diameter 42 of the worm 40 is larger than the outer diameter 44 of the drive shaft 22 in the remaining area of the drive shaft 22. The worm 40 meshes with a worm wheel 46, which with its

Hub 45 is mounted on a bearing dome 48 and a bearing pin 49. The bearing dome 48 is formed, for example, in one piece with the bottom surface 50 of the transmission housing 36. The transmission housing 36 has a circular, radial wall 52, which has an opening 53 to the screw 40 out. The worm 40 forms with the worm wheel 46 a worm toothing 47, which is designed to be particularly efficient in terms of efficiency. Thus, the worm gear 47 has a reduced pressure angle (4 ° to 8 °) and a reduced coefficient of friction of approximately 0.025. Furthermore, a special lubricant is arranged in the gear teeth 47, which significantly reduces the friction of the worm gear 47. Likewise, the worm wheel 46 is mounted on the bearing dome 48 by means of a special lubricant.

In the exemplary embodiment according to FIG. 1, the gear drive unit 10 has a self-locking device 60, which is designed to be movable as a disengagement lock 61 along the bearing pin 49 of the worm gear 47. For this purpose, a coupling element 62 along the Schneckenradachse 58 which rest on a corresponding surface profile 68 of the worm wheel 46. Due to a relative

Rotary movement of the coupling element 62 relative to the worm wheel 46, the coupling element 62 performs a movement along the Schneckenradachse 58, wherein a resilient return element 68 applies a corresponding counterforce against the disengagement of the coupling element 62. The coupling element 62 is rotatably connected to an output member 70, which transmits the torque, for example, to a part to be adjusted on the motor vehicle. The output element 70 is axially fixed in the exemplary embodiment by means of a clamping ring 73 on the bearing pin 49. In the disengaged state, the coupling element 62 with the worm wheel 46 is freely rotatable by the drive motor 12. However, acts a load torque from the drive member 70 to the transmission drive unit 10, the

Coupling element 62 due to the relative movement to the worm wheel 46 and the surface profile 66 along the worm wheel 58 relative to the transmission housing 36 is engaged. As a result, a positive connection 72 forms between the coupling element 62 and the transmission housing 36, which locks upon the action of a load torque. In the exemplary embodiment, the form-fit 72 is formed, for example, as a circumferential toothing 74 of the coupling element 62, which engages in a corresponding Gegenausformung 76 of the gear housing 36 - for example in the circular gear wall 52 -. The output element 70 is designed as an output pinion 71 with an outer toothing, which is operatively connected, for example, with a lifter mechanism of a window lifter.

The pole pot 16 is connected to the transmission housing 36 via its cylindrical extension 38. In this case, the inner surface 17 of the pole pot 16 is supported radially on the outer surface 39 of the cylindrical extension 38. The cylindrical extension 38 For example, has a collar 78 to which a ring seal 80 - for example, an earring - is applied, which is pressed by the pole pot 16 against the collar 78. The pole pot 16 is connected by means of plastic material deformation 94 positively connected to the cylindrical extension 38. In this case, for example, the pole pot 16 by means of stamping tools against the outer surface 39 of the cylindrical

Extension 38 caulked. Inside the cylindrical extension 38, a brush holder 82 is arranged, which surrounds the drive shaft 22 in an annular manner. On the brush holder 82 carbon brushes 84 are arranged, which are formed in the embodiment as a hammer brush 85. The hammer brushes 85 have spring levers 83, which extend along the drive shaft 22, and abut the commutator 26.

Further electronic components 86 are arranged on the brush holder 82, for example interference suppression elements 87 (chokes, capacitors, diodes) and a thermal protection switch 88. In addition, metallic shielding plates 89 for shielding the electromagnetic radiation (Farraday cage) may be arranged on the brush holder 82. Likewise, magnetic sensors 90 are arranged, which for

Rotary position detection of the drive shaft 22 detect the magnetic encoder signal of a sensor magnet 92, which is arranged, for example, a ring on the drive shaft 22. The ball bearing 32 is mounted relatively close to the worm 40 on the drive shaft 22 and is in the assembly after insertion into the cylindrical extension 38 by means of a fixing element 31 within the cylindrical

Extension 38 braced.

From the brush holder 82, connector pins 96 lead out of the transmission case 36, which are injected into the transmission case 36, for example. About this connector pins 96, the electrical current and / or sensor signal transmission is ensured. At the outer periphery of the gear housing 36 Befestigungsdome 108 are formed, with which the transmission drive unit 10, for example, to the body - especially screwed to the vehicle door - is.

FIG. 2 shows a cross section through the pole pot 16 with the ring magnet 18 in order to define the size ratios of the outside diameters 100, 101 and the wall thicknesses 102, 103 of the pole housing 16 and of the ring magnet 18. Between the ring magnet 18 and the pole pot, for example, an adhesive 105 is arranged as a connecting means. FIG. 3 shows an alternative embodiment in which the self-locking device 60 has a wrap spring 55 as a blocking element. In this case, the wrap spring 55 is arranged between the worm wheel 46 and the transmission housing 36. The wrap spring 55 is circular, coaxial with the worm wheel 46 and is pressed against the inside of the circular gear wall 52 in the locked state of the transmission 14. In this case, spring ends 56 of the wrap spring can be angled radially inwards in order to form a positive connection with the worm wheel 46 or the driver 70. In this embodiment, no bearing pin 49 is arranged in the gear housing 36, but a

Through hole 51 in the bottom surface 50, wherein the worm wheel 46 is mounted directly on the molded bearing dome 48.

It should be noted that, with regard to the exemplary embodiments illustrated in the figures and in the description, a variety of possible combinations of the individual features are possible with one another. Thus, for example, the wrap spring 55 can be varied as desired with respect to its geometric shape and its material properties, and have, for example, a jacket which influences the friction with respect to the surface of the gear housing 36. Likewise, the number of windings and the arrangement and

Forming the spring ends 56 are adjusted accordingly. The arrangement of the load torque lock 60 according to the invention within the transmission 14 can also be varied, with an arrangement between the last output element 70 and the worm wheel 46 is particularly favorable to protect the gear teeth 47 from excessive load. The

Coupling element 62 may be formed directly as a driven element 70 or as a driving element operatively connected thereto. Likewise, the concrete shape of the contact surface of the wrap spring depending on the shape of the wrap spring 54, the worm wheel 46 and the coupling element 62 can be varied in many ways. Preferably, the transmission drive unit 10 is the

Adjusting moving parts, such as a disc, a sunroof, a wiper, a seat part or a drive component used in the motor vehicle. In this case, at least a part of the transmission 14 - and thus also the self-locking device 60 - be formed as part of the part to be adjusted, or its adjustment system. The customer connection interface between the drive motor 12 and the adjustment system can be chosen so that the self-locking device 60 is integrated in the adjustment of the part to be adjusted, or disposed in the transmission housing 36, which is directly connected to the pot 16.

Claims

claims

1. gear drive unit (10), in particular for adjusting moving parts in the motor vehicle, with a drive motor (12) and a driven by this gear (14), wherein the transmission (14) has an output element

(70) and a self-locking device (60) with a blocking element (62, 55), and the blocking element (62, 55) blocks the transmission (12) for torques, which are introduced from the output member (70) on the transmission (12) , characterized in that the transmission (12) with its gear teeth (47) and a motor shaft bearing (32, 28) optimized efficiency with minimal friction, and the drive motor (12) as a field magnet, a sleeve-shaped ring magnet (18), in a a magnetic return forming Poltopf (16) is arranged.

2. gear drive unit (10) according to claim 1, characterized in that the ring magnet (18) in the circumferential direction two or more, preferably exactly four - magnetic poles (19).

3. gear drive unit (10) according to any one of claims 1 or 2, characterized in that the ring magnet (18) has a radial wall thickness (102) between 0.5 and 3 mm - preferably between 0.5 and 1.5 mm - and / or a ratio of the outer diameter (100) to the wall thickness (102) between 15: 1 and 40: 1.

4. gear drive unit (10) according to any one of the preceding claims, characterized in that the ring magnet (18) is formed as a high energy magnet and contains rare earth elements, and in particular of sintered or bound in plastic NdFeB is formed.

5. gear drive unit (10) according to one of the preceding claims, characterized in that the pole pot (16) is formed as a deep-drawn part with a circular outer diameter (101) of about 25 to 33 mm and a radial wall thickness (103) of the first up to 2 mm.

6. gear drive unit (10) according to one of the preceding claims, characterized in that the drive motor (12) has a rotor with a disc pack (20) for the electric wire winding (24), wherein the slats (21) has a material thickness in the axial Direction (23) of less than 1.0 mm.

7. gear drive unit (10) according to one of the preceding claims, characterized in that the transmission (14) is designed as a worm gear (14) and the worm gear (47) has a reduced pressure angle - in particular 4 ° to 8 ° and a coefficient of friction approximately 0.025.

8. gear drive unit (10) according to one of the preceding claims, characterized in that a drive shaft (22) by means of a sliding bearing (28) - which is in particular made as a sintered bronze bushing (29) - in the pole pot (16) and by means of a Ball bearing (32) in the gear housing (36) is mounted.

9. gear drive unit (10) according to one of the preceding claims, characterized in that the drive shaft (22) in the transmission housing

(36) and pole housing (16) is mounted in the axial direction (23) exclusively by the trained as a fixed bearing ball bearing (32).

10. gear drive unit (10) according to one of the preceding claims, characterized in that the diameter (44) of the drive shaft (22) between 5 and 7 mm - in particular 6 mm - is, and the screw (40) on the drive shaft ( 22) is rolled up and has a larger outer diameter (42) than the diameter (44) of the drive shaft (22).

11. Transmission drive unit (10) according to one of the preceding claims, characterized in that the transmission (14) has a worm wheel (46) which is mounted on a bearing pin (49) or bearing dome (48) made of plastic

12. gear drive unit (10) according to one of the preceding claims, characterized in that on a circular ring around the drive shaft (22) arranged brush holder (82) in the axial direction (23) hammer brushes (85), wherein the hammer brushes (85 ) are preferably offset by approximately 90 ° with respect to the circumferential direction.

13. Transmission drive unit (10) according to one of the preceding claims, characterized in that the pole pot (16) by means of plastic material deformation (94) with the transmission housing (36) is connected, and in particular on a sleeve-shaped axial extension (38) of the transmission housing (36) is deferred.

14. gear drive unit (10) according to one of the preceding claims, characterized in that the blocking element (62, 55) as a wrap spring

(55) is formed, which - in particular radially - between the worm wheel (46) and the transmission housing (36) is arranged.

15. Transmission drive unit (10) according to one of the preceding claims, characterized in that the wrap spring (55) with her

Outer diameter (42) on the inner wall (52) of the gear housing (36) comes to rest and with their ends (56) - in particular directly - with the worm wheel (46) and the output member (70) is connected.