Actuator for an actively adjustable roll stabilizer

Abstract

Actuator (2) for an actively adjustable roll stabilizer (1) of a motor vehicle, comprising a housing (5) that accommodates a drive unit (6) and a multi-stage planetary gear (7) driven therein, wherein each stage of the planetary gear (7) comprises a sun gear (11, 21, 31), at least one planet gear (12, 22, 32) and a ring gear, and wherein in each stage the at least one planet gear (12, 22, 32) is in meshing engagement with the sun gear (11, 21, 31) of the same stage and the ring gear of the same stage, wherein the ring gear of at least one stage of the planetary gear (7) is formed as part of the housing (5), characterized in that the housing (5) is designed in multiple parts by comprising several axially adjacent, interconnected housing sections (5a, 5b, 5c), wherein at least two of the housing sections (5b, 5c) each comprise a ring gear of a planetary stage train.

Description

[0001] The invention relates to an actuator for an actively adjustable roll stabilizer of a motor vehicle according to the preamble of claim 1. The invention further relates to a method for manufacturing a housing of such an actuator, according to claim 12.

[0002] To increase vehicle stability and ride comfort, it is common practice in chassis engineering to equip vehicles with a so-called roll stabilizer. In its simplest form, this is essentially a C-shaped torsion bar spring, which is rotatably mounted relative to the body in its central section, and whose outer, opposing ends are each connected to a wheel suspension. This design ensures that, when cornering, the vehicle body not only compresses on the outside side (due to centrifugal force), but also that the inside wheel is lowered (resulting in body roll).

[0003] To further enhance ride comfort, it is known from the prior art to design such roll stabilizers with active adjustability. In this case, the roll stabilizer comprises an actuator and is divided into two stabilizer sections that can be rotated relative to each other by means of the actuator. By rotating the stabilizer sections relative to each other – about an axis of rotation – a roll movement of the vehicle body, in passenger cars in particular the body, is deliberately generated, or a roll movement of the vehicle body caused by external influences is deliberately counteracted. According to a technically advantageous design, an electric motor, which is housed in a casing of the actuator, serves as the drive unit. To achieve a suitable torque and speed at the actuator output, the drive unit is typically connected to a multi-stage planetary gearbox.

[0004] In a manner known from other designs, each stage of the planetary gear set comprises a centrally located sun gear, a set of planet gears, and a ring gear. The planet gears are each rotatably mounted about their own axis of rotation relative to a planet carrier. The planet gears of each stage mesh with the equally matched sun gear and the equally matched ring gear, the ring gear being formed as part of the housing.

[0005] In this context, reference is made to DE 10 2017 209 146 A1, which discloses an actuator for an actively adjustable roll stabilizer according to the features of the preamble of claim 1. The features described therein Fig. 1a, Fig. 1b, Fig. Figure 1c shows that the actuator housing accommodates a three-stage planetary gear set. The ring gears of each of the three planetary stages are integrated into the housing. For this purpose, a toothed section is formed on an inner area extending across the axial length of the multi-stage planetary gear set, providing a ring gear for each stage. Since the ring gears of the different planetary stages have identical dimensions and tooth configurations, an assembly consisting of planet gears, planet carriers, and sun gears can be inserted axially into the housing and fully positioned for operation via the toothed section. This design and assembly method requires that the ring gears on all planetary stages have identical diameters and tooth configurations.

[0006] For technical reasons, it may be necessary and / or advantageous to provide a different design for the ring gear of one or more planetary stages compared to other planetary stages, particularly with regard to its size and / or tooth configuration. For example, it may be necessary to provide the first planetary gear stage with helical teeth, while subsequent stages, such as the second and third, have straight teeth. Additionally or alternatively, it may be technically necessary for the ring gear of one or more stages of the planetary gear to have a different diameter than the other stages. For example, it is conceivable that the ring gear of the first planetary gear stage has a smaller diameter than the ring gears of the second and third stages of the planetary gear.In the aforementioned cases, which deviate from the simple design shown in DE 10 2017 209 146 A1, the production of a multi-stage, internal toothing on the actuator housing is required, which is technically complex in terms of manufacturing when the actuator is of a conventional design.

[0007] US 2010 / 0072725A discloses a further actuator for an actively adjustable roll stabilizer with features of the preamble of claim 1. This comprises a drive unit and a reduction gear formed from two assemblies (reference numbers 4 and 5 therein) with different gear types. According to a [document / reference] therein Fig. In the first embodiment shown in Figure 1, the actuator housing (not explicitly labeled) comprises a harmonic gear and a two-stage planetary gear, all designed as a single unit. A multi-part housing design can be seen in the illustration of Fig. 1 cannot be removed. In contrast, in an alternative second embodiment (there) Fig. 2) The actuator comprises a wave gear and a single-stage Wolfrom gear with a modular design. As indicated in the drawings and described in

[0018] , these are structurally separate (gear) units 4 and 5, which are connected to each other (via claw clutches). It is further noted that the units can be freely combined with regard to their arrangement and sequence.

[0008] It is an object of the present invention to provide an actuator for an actively adjustable roll stabilizer of the type described by the preamble of claim 1, which, despite complex gearing, in particular internal gearing that differs for several stages, can be manufactured simply. Furthermore, a method for manufacturing a housing for an actuator that satisfies this requirement is to be provided.

[0009] The aforementioned problem is initially solved by an actuator according to the features of claim 1. This actuator is for an actively adjustable roll stabilizer of a motor vehicle, comprising a housing that accommodates a drive unit and a multi-stage planetary gear unit driven by it. Each stage of the planetary gear unit has a sun gear, at least one planet gear, and a ring gear, and in each stage, the at least one planet gear is in meshing engagement with the sun gear and the ring gear of the same stage. The ring gear of at least one stage of the planetary gear unit is formed as part of the housing. The actuator is characterized in that the housing is designed in multiple parts, comprising several axially adjacent, interconnected housing sections, wherein at least two of the housing sections each form a ring gear of a planetary stage.

[0010] The invention is based on the consideration that, due to the difficult accessibility for appropriate tools, manufacturing a multi-stage internal gear on the actuator housing to form one or more ring gears for a multi-stage planetary gear unit housed therein is extremely complex. The invention therefore developed the idea of ​​constructing the housing in multiple parts in the area of ​​the housed gear unit. By dividing the housing into several axially adjacent housing sections, the gear teeth required to form ring gears can initially be manufactured separately on each housing section. Access to the respective gear teeth area is thus significantly simplified. Accordingly, machining is performed on at least two housing sections, with the result that each of these forms a ring gear for a planetary stage.By joining the housing sections produced in this way, the housing can be manufactured in a comparatively simple manner despite its multi-stage internal gearing; thus, the actuator can also be produced with relatively little effort. The problem mentioned at the beginning is thereby solved.

[0011] According to an advantageous embodiment, the ring gear of a preferably first stage of the planetary gear set is formed on the inner side of an annular component that forms a housing section. The annular component preferably has an axial length sufficient at least for forming the ring gear of the first planetary stage. Designing a housing section as an annular component allows for relatively simple gearing due to the easy accessibility to the inner side of the annular component. Advantageously, the gearing formed on the annular component is a helical gear.

[0012] Another advantageous embodiment of the actuator provides that a housing section forms a ring gear for two planetary stages by having at least one toothed section on this housing section that meshes with a planetary gear of the second stage and a planetary gear of the third stage. Provided that identical toothed sections are required for the second and third stages of the planetary gear set, this method simplifies manufacturing, as a single component machining operation (a common ring gear) is possible for both planetary stages.

[0013] Particularly easy manufacturing is achieved if the toothing formed on the aforementioned housing section is a straight toothing.

[0014] A structurally preferred embodiment of the actuator provides that the housing has at least three housing sections, of which a first housing section surrounds the drive unit in a clasp-like manner, of which a second housing section forms the ring gear of the first planetary stage, and of which a third housing section forms the ring gear of the second and preferably also the third planetary stage.

[0015] The connection of the housing sections provided according to the invention can be effected in various ways. Advantageously, a housing section is connected to an axially adjacent housing section by a positive-locking and / or force-locking connection. According to a specific embodiment, axially adjacent housing sections can overlap axially in certain areas to form an interference fit, particularly in the radial direction, in the overlap area. Such a design achieves a positive-locking and force-locking connection of the housing sections.

[0016] In addition, a further advantageous development of the actuator provides that a housing section is materially connected to an axially adjacent housing section, in particular welded to each, preferably along an outer circumferential weld seam.

[0017] Preferably, the ring gear of the first stage of the planetary gear has a smaller diameter than the ring gear of the second and / or third stage of the planetary gear.

[0018] Advantageously, the actuator is designed such that the drive unit, in particular the electric motor, the sun gears, and the ring gears are arranged coaxially with respect to a rotational axis. With this arrangement, the actuator—given a suitable housing design—exhibits rotational symmetry and thus a substantially cylindrical outer shape.

[0019] The aforementioned problem is also solved by a method for manufacturing a housing for an actuator as described above, according to claim 12. The method is characterized by the following steps: Manufacturing several housing sections, wherein at least two of the housing sections each have a toothed section formed in order to produce a ring gear corresponding to a stage of a multi-stage planetary gear, Joining and connecting the housing sections to form a common housing.

[0020] Regarding the advantages that can be achieved, in particular the simplified manufacturing of a multi-stage internal gear, reference is made to the previous explanations concerning the actuator according to the invention, which also apply accordingly to the method according to the invention.

[0021] The method according to the invention can also advantageously include welding adjacent housing sections together all around from the outside.

[0022] The invention is explained in more detail below with reference to an embodiment illustrated in the accompanying drawing. Further advantageous features and effects of the invention will also become apparent from this. The drawing shows: Fig. 1. An actively adjustable roll stabilizer of a motor vehicle in a simplified perspective representation, Fig. 2 a sectional view of a part of an actuator that is essential for explaining the invention, Fig. 3 a part of the housing of the in Fig. 2 actuators shown in sectional view, Fig. 3a a detail from Fig. 3 (area circled there).

[0023] First, it shows Fig. Figure 1 illustrates the application area of ​​the invention with a schematic view of an actively adjustable roll stabilizer 1 of a motor vehicle. The roll stabilizer 1 is part of a chassis of a vehicle (not shown), which is not fully depicted. A right wheel 4a and a left wheel 4b located on the opposite side of the vehicle are connected to the vehicle body via wheel suspensions, which will not be explained in detail here. Each wheel suspension is coupled to one end of a corresponding right stabilizer section 3a and left stabilizer section 3b, respectively, via an (unlabeled) pendulum support. The two stabilizer sections 3a and 3b are connected to each other centrally via an actuator 2.

[0024] In a manner known in itself, the actively adjustable roll stabilizer 1 is rotatably mounted about a rotational axis 10 relative to the vehicle body (mounting not shown). The actuator 2, in Fig. 1 simplified representation as a cylindrical body, essentially comprises a housing 5 which contains a drive unit 6 in the form of an electric motor (see Fig. 2) and a multi-stage planetary gear 7 driven by it (see also Fig. 2) receives. The stabilizer sections 3a and 3b (see figure) are connected via the drive unit 6 and the multi-stage planetary gear 7 within the actuator 2. Fig. 1) in drive connection. When the electric motor is stationary, the two stabilizer sections 3a, 3b are rigidly connected to each other via the actuator 2. By operating the electric motor, the stabilizer sections 3a, 3b can be rotated relative to each other about the axis of rotation 10, depending on the direction of rotation of the electric motor. In this way, the roll stabilizer 1 can be adjusted in a manner known in isolation.

[0025] In the Fig. 2, Fig. 3 and Fig. 3a describes an actuator according to the invention using an exemplary embodiment, which can be attached, for example, to a device as described in Fig. 1. The schematically depicted roll stabilizer 1 can be used. Fig. Figure 2 shows a sectional view of a part of the actuator that is essential for explaining the invention. With respect to a rotational axis 10, the actuator 2 has an externally essentially rotationally symmetrical, cylindrical basic shape, comparable to the illustration in Figure 2. Fig. 1. A housing 5 extends in a cylindrical shape around the axis of rotation 10. An electric motor 6 is arranged inside the housing 5 as a drive unit. A three-stage planetary gear 7, which can be driven by the electric motor 6, is located axially adjacent to the electric motor 6. The output of the planetary gear 7 is via a third-stage planet carrier 33, which in turn is connected via a coupling element (not shown) to an output element 34. The output element 34 is rotatably mounted relative to the housing 5 about the axis of rotation 10 via a double angular contact ball bearing (not specified). In the assembled state, the output element 34 is connected to the stabilizer section 3a of an adjustable roll stabilizer 1 (see Figure 1). Fig. 1) is connected in a rotationally fixed manner. An opposite one, shown in the drawing of Fig. 2 The axial end of the actuator 2, not shown, has a housing-fixed connection of the left stabilizer section 3b to the housing 5.

[0026] How Fig. As can be seen from Figure 2, the planetary gear set 7 is divided into three stages. Each stage of the planetary gear set 7 has a sun gear 11, 21, 31, a number of planet gears 12, 22, 32, and a ring gear associated with the housing 5. In the first stage of the planetary gear set 7, a number of planet gears 12 mesh with the sun gear 11, which is arranged coaxially with the axis of rotation 10, and a ring gear associated with the housing 5. In the second stage of the planetary gear set 7, a number of planet gears 22 mesh with the sun gear 21 and a ring gear formed on the housing 5. In the third stage of the planetary gear set 7, a number of planet gears 32, each designed as a mutually interlocking gear pair, mesh with the sun gear 31 and the ring gear formed on the housing 5.By means of the multi-stage planetary gear 7 designed in this way, a drive power provided by the electric motor 6 is translated in terms of speed and torque into an output power provided at the third stage planet carrier 33.

[0027] The housing 5 of the actuator 2 is characterized by its multi-part design. How Fig. As can be seen from Figure 2, the housing 5 is divided into three axially adjacent housing sections 5a, 5b, and 5c. The housing sections 5a, 5b, and 5c are each positively, frictionally, and materially connected to one another. For this purpose, housing section 5b, which is designed as an annular component 9 and forms the ring gear of the first stage of the planetary gear 7, has an axial overlap area with the adjacent housing sections 5a and 5c, and in this overlap area forms a radially acting press fit (relative to the axis of rotation 10). Fig. 3 as well as in Fig. 3a, which is in Fig. As shown in the circled detail 3, this overlap area is enlarged, at least between housing sections 5b and 5c. The illustration from Fig. Furthermore, it can be seen from 3a that housing section 5b and housing section 5c are welded together along an outer circumferential weld seam 8. Housing section 5b is connected to housing section 5a in a similar manner, as shown from Fig. 2 emerges. Accordingly, the three housing sections 5a, 5b, 5c of the in Fig. The actuator 2 shown is connected to a housing 5.

[0028] Housing section 5b and housing section 5c each form a ring gear of a planetary stage of the three-stage planetary gear set 7. As already mentioned, housing section 5b is formed from an annular component 9, with the ring gear of the first stage of the planetary gear set 7 being formed on the inside of this annular component 9. The annular component 9 is designed for this purpose, as shown in particular in Fig. Figure 3a shows a toothed section 5bz, which is designed as a helical tooth. Due to the multi-part nature of the housing 5, the helical toothed section 5bz on the ring-shaped component 9 can be applied with relatively little manufacturing effort before the housing sections 5a, 5b, 5c are joined, thanks to the easy accessibility of the individually available ring-shaped component 9.

[0029] Adjoining housing section 5b is a housing section 5c, which forms a single ring gear for two planetary stages, namely the second and third stages of the multi-stage planetary gear 7. In other words, the second and third stages of the planetary gear 7 use the same ring gear, manufactured together, on housing section 5c. For this purpose, housing section 5c is designed as follows: Fig. 3a shows that a toothing 5cz is formed, which according to the illustration of Fig. 2 is in meshing engagement with both the planet gears 22 of the second stage and the planet gears 32 of the third stage. The toothing 5cz formed on housing section 5c is a straight toothing.

[0030] Dividing the housing 5 into several housing sections 5a, 5b, 5c allows for the production of a multi-stage internal gearing on the housing 5 with relatively little manufacturing effort. In particular, a desired gearing 5bz or 5cz, corresponding to a stage of the three-stage planetary gear 7, can first be produced separately on housing section 5b and housing section 5c, respectively. Only after the housing sections 5a, 5b, 5c have been manufactured are they joined and connected to form the common housing 5. For this purpose, the housing sections 5a, 5b, 5c are first joined axially, in particular by pressing them against each other, thus creating a sufficient press fit, before being welded together circumferentially from the outside.

[0031] How Fig.2 removable, the ring gear 5b of the first stage of the planetary gear 7 has a smaller diameter than the ring gear 5c of the second and third stages of the planetary gear 7.

[0032] It should be noted that housing designs differing from the embodiment shown in the figures are conceivable. For example, a different division of the housing sections is possible. The multi-stage planetary gear could have a different number of stages than three; the housing sections could feature different types of gearing or diameters of the respective ring gear. Reference sign 1 actively adjustable roll stabilizer 2 Actuator 3a (3b) right (left) stabilizer section 4a (4b) right (left) wheel 5 cases 5a first housing section (motor side) 5b second casing section (first planetary stage) 5bz gearing (first planetary stage) 5c third housing section (output side) 5cz gearing (second and third planetary stage) 6 electric motor 7 multi-stage planetary gear 8 weld seam 9 ring-shaped component 10 Rotation axis 11 Sun wheel, first stage 12 First stage planetary gear 21 Sun wheel, second stage 22 Second stage planetary gear 31 Sun wheel, third stage 32 third-stage planetary gear 33 third-level planetary carriers 34 Output element

Claims

[1] Actuator (2) for an actively adjustable roll stabilizer (1) of a motor vehicle, comprising a housing (5) which accommodates a drive unit (6) and a multi-stage planetary gear (7) driven thereby, wherein a stage of the planetary gear (7) comprises a sun gear (11, 21, 31), at least one planet gear (12, 22, 32) and a ring gear, and wherein in each stage the at least one planet gear (12, 22, 32) is in meshing engagement with the sun gear (11, 21, 31) of the same stage and the ring gear of the same stage, wherein the ring gear of at least one stage of the planetary gear (7) is formed as part of the housing (5), characterized by , that the housing (5) is designed in multiple parts by comprising several axially adjacent, interconnected housing sections (5a, 5b, 5c), wherein at least two of the housing sections (5b, 5c) each form a ring gear of a planetary stage. [2] Actuator according to claim 1, characterized by, that the ring gear of a preferably first stage of the planetary gear (7) is formed on an inner side of an annular component (9) which forms a housing section (5b). [3] Actuator according to claim 2, characterized by , that the toothing (5bz) formed on the ring-shaped component (9) is a helical toothing. [4] Actuator according to any of the preceding claims, characterized by , that a housing section (5c) of the housing (5) forms a ring gear for two planetary stages by having at least one toothing (5cz) on this housing section (5c) which meshes with a planet gear (22) of the second stage and a planet gear (32) of the third stage. [5] Actuator according to claim 4, characterized by , that the toothing (5cz) formed on the housing section (5c) is a straight toothing. [6] Actuator according to any of the preceding claims, characterized by, that the housing (5) has at least three housing sections (5a, 5b, 5c), of which a first housing section (5a) surrounds the drive unit (6) in a shell-like manner, of which a second housing section (5b) forms the ring gear of the first planetary stage, and of which a third housing section (5c) forms the ring gear of the second and preferably also of the third planetary stage. [7] Actuator according to any of the preceding claims, characterized by , that a housing section (5a, 5b, 5c) is positively and / or force-fit connected to an axially adjacent housing section (5a, 5b, 5c). [8] Actuator according to any of the preceding claims, characterized by , that the housing section (5b) and a housing section (5a, 5c) overlap axially in some areas in order to form a press fit, particularly in the radial direction, in the overlap area. [9] Actuator according to any of the preceding claims, characterized by, that a housing section (5a, 5b, 5c) is welded to an axially adjacent housing section (5a, 5b, 5c), preferably along an outer circumferential weld seam (8). [10] Actuator according to any of the preceding claims, characterized by , that the ring gear of the first stage of the planetary gear (7) has a smaller diameter than the ring gear of the second and / or third stage of the planetary gear (7). [11] Actuator according to any of the preceding claims, characterized by , that the drive unit (6), the sun gears (11, 21, 31) and the ring gears are arranged coaxially with respect to a rotational axis (10). [12] Method for manufacturing a housing (5) of an actuator (2) according to any one of the preceding claims, characterized by the steps: Manufacturing several housing sections (5a, 5b, 5c), wherein at least two of the housing sections (5b, 5c) are each provided with a toothing (5bz, 5cz) to produce a ring gear corresponding to a stage of a multi-stage planetary gear (7), Joining and connecting the housing sections (5a, 5b, 5c) to form a common housing (5). [13] Method according to claim 12, characterized by , that adjacent housing sections (5a, 5b, 5c) are each welded together all around from the outside.

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