Friction clutch

Abstract

Friction clutch (101, 102) which has: a pivot axis (d) around which the friction clutch (101, 102) is arranged, an actuator mechanism (113), a lever element (103, 104), an electric motor (3, 3a) which is arranged with respect to its rotor axis (d(r)) substantially perpendicular to the axis of rotation (d), a clutch actuator (1, 1a) for actuating the actuator mechanism (113) driven by the electric motor (3, 3a), which displaces the lever element (103, 104) axially to the axis of rotation (d) along an actuation path, a planetary gear set (4, 4a) arranged coaxially to the rotor axis (d(r)), which reduces the rotor speed and an engagement element (107, 108) which is axially displaced by a rotary lever (109, 109a) driven by the planetary gear (4, 4a) and which is contained in the actuator mechanism (113), characterized in that the planetary gear (4, 4a) is designed as a three-stage planetary gear, wherein a first and second planetary stage (I, II) are designed as a two-shaft gear and a third planetary stage (III) is designed as a three-shaft gear.

Description

[0001] The invention relates to a friction clutch according to the preamble of claim 1.

[0002] Clutch actuators are used to actuate friction clutches in motor vehicle drivetrains. The friction clutch, arranged around a rotational axis, is actuated by axial displacement of a lever element, depending on the design of the friction clutch. A friction clutch that is closed in the non-actuated state by means of a lever element designed as a disc spring can be pulled or pushed open at the disc spring tips coaxially to the rotational axis, while a friction clutch that is open in the non-actuated state can be pushed or pulled closed, for example, by means of the lever tips of a lever spring. Two such friction clutches can be combined to form a double clutch, so that two clutch actuators, either separate or combined into a single unit, each actuate one friction clutch.

[0003] Clutch actuators of this type are driven by an electric actuator, which is controlled by a control unit so that the desired torque to be transmitted is quickly and reproducibly activated. Examples of clutch actuators equipped with an electric actuator are known from the documents DE 10 2008 013 054 A1 and DE 10 2004 009 832 A1. In each case, a rotor axis of the actuator is arranged essentially perpendicular to the rotational axis of the friction clutch. A corresponding gear is provided to convert the rotary movement of the actuator rotor into a linear movement. Depending on the clutch position, different forces must be applied over the actuation path of the friction clutch, so the actuator must be designed for the maximum force.Furthermore, servo motors with low speeds are comparatively large for the required power, so that high-speed servo motors may be used in conjunction with a reduction gear.

[0004] The object of the invention is therefore to design a friction clutch with a space-saving clutch actuator with a large gear ratio.

[0005] The object is solved by the subject matter of claim 1. The dependent claims represent advantageous embodiments.

[0006] The proposed friction clutch has a clutch actuator for actuating the friction clutch arranged about a rotational axis and contains a servomotor arranged essentially perpendicular to the rotational axis with respect to a rotor axis. This servomotor displaces a lever element of the friction clutch, for example a lever element such as a disc spring or lever spring of the friction clutch, axially to the rotational axis along an actuation path by means of an actuator mechanism. The lever element can be displaced in a pushing or pulling manner. Depending on the design of the friction clutch, the friction clutch can thereby be forcibly closed or opened. The speed of the servomotor is reduced to low speed by means of a planetary gear arranged coaxially to the rotor shaft and reducing the rotor speed. The actuator mechanism contains a rotary lever that is rotationally driven by the planetary gear and axially displaces an actuating sleeve.

[0007] In a particularly advantageous manner, two clutch actuators can be combined to actuate the friction clutches of a dual clutch. The rotary levers and the actuating sleeves displaced by them can be nested within each other, so that one friction clutch is actuated at a larger diameter and the other at a smaller diameter. In this case, one friction clutch can be actuated by pulling and the other by pushing, by changing the rotational directions of otherwise identical clutch actuators.

[0008] The planetary gear train is designed according to the invention as a three-stage planetary gear train. In this case, a first and second planetary stage are designed as a two-shaft gear train, and a third planetary stage is designed as a three-shaft gear train. Preferably, the second two-shaft gear train and the three-shaft gear train form a positive gear train with a high reduction ratio. For example, a high-speed electric motor with comparatively low power can be provided, which is correspondingly reduced by means of the positive gear train. For this purpose, gear ratios of the motor speed to low speed are proposed, i.e. reduction ratios of 100 to 600, preferably approximately 300. The module of the gearing is preferably set to be equal to or less than one, so that a small installation space can be provided for the gear train.It has proven advantageous to design the module so that the electric motor and planetary gear have essentially the same outer diameter, allowing the planetary gear to be flanged directly to the rotor, or allowing an input shaft or sun to be formed from it as a single piece. In this case, a single unit with a uniform outer diameter can be provided.

[0009] According to an advantageous embodiment, the first and second planetary stages have a common, rotationally fixed ring gear, for example, integrated into a housing of the planetary gear or the housing common to the electric motor and the planetary gear.

[0010] Furthermore, the first and second planetary stages can have a common planetary carrier with planets distributed around the circumference and meshing with ring gears of the second and third planetary stages. In this case, a sun gear of the first planetary stage can be non-rotatably connected to the rotor shaft, and a planetary carrier can be non-rotatably connected to a sun gear common to the second and third planetary stages.

[0011] It has also proven advantageous to set the same gearing between the sun gears and planets of the three planetary stages. To achieve a high reduction ratio, the difference between the number of teeth of the ring gear of the first planetary stage and the common ring gear of the second and third planetary stages can, in particular, correspond to a maximum of the number of planets in the second and third planetary stages.

[0012] In a further advantageous embodiment of the planetary gear, the ring gear of the third planetary stage can have a positive profile shift and the common ring gear of the first and second planetary stages can have a negative profile shift.

[0013] In summary, the invention relates to a clutch actuator in the form of a rotary lever actuator arranged perpendicular to the axis of a friction clutch to be actuated, in which the torque of the rotary lever is provided via an electric motor and an intermediate epicyclic gear. The epicyclic gear, such as a planetary gear, has a total gear ratio between 100 and 600 thanks to its multi-stage design, with a particularly advantageous variant having a gear ratio of approximately 300. The modulus of the gearing is less than 1 in order to enable the most compact installation space possible. The dimensions of the rotary lever actuator can thus be limited to a diameter of less than 50 mm. The overall length of the epicyclic gear can be less than 30 mm.

[0014] The invention is based on the Fig. 1 to 5 are explained in more detail. They show: Fig. 1 a partial section through a double clutch with a clutch actuator for actuating a friction clutch of the double clutch, Fig. 2 a schematic view of an actuating device of the double clutch of the Fig. 1 with two clutch actuators, Fig. 3 a gear diagram of a planetary gear of the clutch actuator of the Fig. 1 and Fig. 2, Fig. 4 a 3D view of an embodiment of the planetary gear of the Fig. 3 with a view of the opened gearbox and Fig. 5 a section through the planetary gear of the Fig. 4.

[0015] The Fig. Figure 1 shows a section through the upper half of the dual clutch 100 with the engaged friction clutch 101 and the engaged friction clutch 102. The friction clutches 101, 102 are each actuated by means of an axial displacement of the lever elements 103, 104, wherein an engaging element 107, 108, decoupled by means of the actuating bearings 105, 106, is displaced axially along the rotational axis d of the dual clutch 100 by a clutch actuator 1. For this purpose, the clutch actuator 1, which is arranged perpendicular to the rotational axis d of the dual clutch 100 with respect to its rotor axis d(r), rotates the actuator mechanism 113. This contains the rotary lever 109 visible in detail D, so that the engaging element 107 is displaced axially along the sleeve part 110 when the drive shaft 2 of the clutch actuator 1 rotates. The clutch actuator 1 is rotatably mounted in the support member 112 by means of the bearing 111. The support member 112 is connected, for example, to a transmission wall by screwing.The clutch actuator 1 is formed from the electric motor 3 and the planetary gear 4 arranged between it and the drive shaft 2.

[0016] The Fig. Figure 2 shows a schematic 3D view of the clutch actuators 1, 1a, which are rotatably mounted on the support member 112 by means of bearings 111, 111a on their drive shafts 2, 2a. The electric motors 3, 3a drive the drive shafts 2, 2a by means of the high-reduction planetary gears 4, 4a arranged between them and the drive shafts 2, 2a, to which the rotary levers 109, 109a are attached. The rotary levers 109, 109a each axially displace engagement elements (not shown) of different diameters, which are radially nested within the sleeve part 110 and kinematically independently of one another.

[0017] The Fig. 3 shows a gear diagram of the clutch actuators 1, 1a of the Fig. 2 integrated planetary gear 4. The planetary gear 4 is formed from the planetary stages I, II, III. In total, the planetary gear 4 forms a gear ratio of preferably 300 in the slow direction between the rotor shaft of the electric motor 3 ( Fig. 1) coaxially connected or one-piece input shaft 5 and the drive shaft 2 for driving the rotary lever 109 ( Fig. 1 and Fig. 2). Here, the input shaft 5 is driven with a low input torque M in , for example 0.1 Nm. Due to the torque-converting properties of the planetary gear 4, output torques M out of approx. 30 Nm.

[0018] The first planetary stage I forms a two-shaft transmission in which the sun gear 7, driven by the input shaft 5, drives the planets 9, which are rotatably arranged on the planet carrier 8 and which simultaneously mesh with the ring gear 10 fixed to the housing. The planetary stage II is also designed as a two-shaft transmission. The sun gear 11 is driven by the planet carrier 8 of the planetary stage I and meshes with the planets 13 mounted on the planet carrier 12. The planets 13 mesh with the ring gear 10, which is fixed to the housing and is designed as a common ring gear for the planetary stages I and II. The planetary stage III is designed as a three-shaft transmission, which shares the sun gear 11, the planet carrier 12, and the planets 13 with the planetary stage II. The planets 13 mesh simultaneously with the ring gear 10 and the ring gear 14 connected to the input shaft 2.The number of teeth of the ring gears 10, 14 differs only slightly, at most by the number of planets 13 distributed over the circumference. This makes it possible to achieve a positive gear with a particularly high gear ratio from the input shaft 5 to the drive shaft 2 in the slow direction, i.e. a high gear reduction when converting a low torque into a high torque.

[0019] The Fig. 4 and Fig. 5 show the planetary gear 4 of the Fig. 3 in a structurally designed embodiment in view with the housing 15 opened ( Fig. 4) and on average ( Fig.5). Planetary stage I has input gearing 16, identical to sun gear 7, to which the rotor of the electric motor is flanged. Disc part 17 forms planet carrier 8 and rotatably accommodates planets 9 on one side. The other side of planets 9 is formed by flange part 18 of sun gear 11. Disc part 19 is rotatably mounted, for example, with a plain bearing, on sun gear 11. This disc part 19, together with disc part 20, forms planet carrier 12 for accommodating planets 13 of planetary stages II, III. Ring gear 10 of planetary stages I, II is integrated with its internal gearing into housing 15. Ring gear 14 of planetary stage III is arranged axially adjacent to housing 15 and is rotationally connected to the drive shaft, for example, by means of cams 21, directly or by means of a sleeve part (not shown) or an axially extended flange part.Due to the compact design of the planetary gear 4, a small outer diameter D(a) of less than 50 mm and a short axial length I of less than 30 mm can be achieved. List of reference symbols 1 clutch actuator 1a clutch actuator 2 drive shaft 2a Drive shaft 3 electric motor 3a Electric motor 4 planetary gears 4a Planetary gear 5 Input shaft 7 Sun gear 8 planet carriers 9 Planet 10 ring gear 11 Sun gear 12 planet carriers 13 Planet 14 ring gear 15 housings 16 Input gearing 17 Disc part 18 Flange part 19 Disc part 20 disc part 21 cams 100 dual clutch 101 Friction clutch 102 Friction clutch 103 Lever element 104 Lever element 105 Actuating bearing 106 operating bearings 107 indenters 108 indenters 109 rotary lever 109a Rotary lever 110 sleeve part 111 warehouses 111a Warehouse 112 supporting part 113 Actuator mechanics D Detail D(a) outer diameter d axis of rotation d(r) rotor axis l length M in Input moment M out Initial moment I Planetary Stage II planetary stage III planetary stage

Claims

[1] Friction clutch (101, 102) comprising: an axis of rotation (d) around which the friction clutch (101, 102) is arranged, an actuator mechanism (113), a lever element (103, 104), an electric motor (3, 3a) which is arranged with respect to its rotor axis (d(r)) substantially perpendicular to the axis of rotation (d), a clutch actuator (1, 1a) for actuating the actuator mechanism (113) driven by the electric motor (3, 3a), which displaces the lever element (103, 104) axially to the rotational axis (d) along an actuating path, a planetary gear (4, 4a) provided coaxially to the rotor axis (d(r)), which reduces a rotor speed and an engagement member (107, 108) which is axially displaced by a rotary lever (109, 109a) which is driven in rotation by the planetary gear (4, 4a) and which is contained in the actuator mechanism (113), characterized bythat the planetary gear (4, 4a) is designed as a three-stage planetary gear, wherein a first and second planetary stage (I, II) are designed as a two-shaft gear and a third planetary stage (III) are designed as a three-shaft gear. [2] Friction clutch (101, 102) according to claim 1, characterized by that the second two-shaft gear and the three-shaft gear form a positive gear with a high reduction ratio. [3] Friction clutch (101, 102) according to claim 1 or 2, characterized by that the first and second planetary stages (I, II) have a common, rotationally fixed ring gear (10). [4] Friction clutch (101, 102) according to one of claims 1 to 3, characterized by that the second and third planetary stages (II, III) have a common planetary carrier (12) with planets (13) distributed over the circumference and meshing with ring gears (10, 14) of the second and third planetary stages (II, III). [5] Friction clutch (101, 102) according to claim 4, characterized by that a sun gear (7) of the first planetary stage (I) is connected in a rotationally fixed manner to the rotor shaft and a planet carrier (8) is connected in a rotationally fixed manner to a sun gear (11) common to the second and third planetary stages (II, III). [6] Friction clutch (101, 102) according to one of claims 3 to 5, characterized by that the same toothing is set between the sun gears (7, 11) and planets (9, 13) of the three planetary stages (I, II, III). [7] Friction clutch (101, 102) according to one of claims 3 to 6, characterized by that a difference in the number of teeth of the ring gear (10) of the first planetary stage (I) and the common ring gear (14) of the second and third planetary stage (II, III) corresponds at most to the number of planets (13) of the second and third planetary stage (II, III). [8] Friction clutch (101, 102) according to one of claims 1 to 7, characterized bythat the ring gear (14) of the third planetary stage (III) has a positive profile shift and the common ring gear (10) of the first and second planetary stages (I, II) has a negative profile shift.

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