KR20180083325A - Actuator - Google Patents

Abstract

The invention relates to an input element, preferably a rotor, a spindle, etc., for transmitting torque; An output element that transmits a torque or a linear force, such as a spindle or a spindle nut; And more particularly to an actuator for actuating a vehicle clutch, comprising at least a region surrounded by a sleeve and a unit for converting rotational motion into linear motion, in which case the different parts affect the efficiency To this end, a friction element is arranged between the part of the actuator driven in a rotational manner and the part of the actuator fixed to the frame / housing, in which case the friction element is arranged outside the sleeve according to the invention.

Description

Actuator

The present invention relates to actuators, and in particular is used to actuate a vehicle clutch.

The actuator can convert the rotational motion of one part into the axial movement of another part. In this case, the actuator itself may be any type of linear actuator, such as, for example, a PWG-actuator (PWG = planetary roller screw drive), a hydraulic slave cylinder,

A planetary roller screw drive (PWG) or a planetary roller screw spindle drive is a spindle; Spindle nut; And is formed from a planetary roller body arranged circumferentially therebetween and received in a single planetary carrier. In this case, the spindle, the spindle nut and the planetary roller body have a profile for transferring rotational motion between the spindle and the spindle nut, in which case one of the components - the spindle or spindle nut - is rotationally driven, Are displaced along the longitudinal axis of the spindle by an axial path corresponding to the set transmission ratio while being fixedly arranged to rotate integrally. In this case, the planetary roller body has two different profile sections, one for engaging the spindle and the other for engaging the spindle nut, wherein one profile section is arranged in a grooved configuration on the planetary roller body And the other profile sections are arranged in a grooved shape in general on the planetary roller body and in some embodiments complementary screw sections are arranged on a spindle or a spindle nut and correspondingly the groove sections have different configurations Are arranged on the elements.

EP 320 621 A1 discloses a planetary roller screw drive in which, for example, a spindle is provided with a screw and a spindle nut is provided with grooves, on which a respective planetary roller body is formed, correspondingly complementary Rolled by the profile section. In this case, the spindle fixedly supported in the axial direction and rotated, for example, by an electric motor, is rotated with respect to the spindle nut fixedly arranged so as to rotate integrally, so that the spindle nut is inevitably and frictionally engaged Is axially displaced in the groove of the spindle nut by the rolling of the equation. In this case, an operation proportional to the number of revolutions of the spindle appears over the axial path of the spindle nut.

For example, in the case of an efficiency-optimized spindle drive (e.g. PWG) driven by an electric motor, a hydrostatic clutch actuator (abbreviated as HCA), for example operating against a clutch characteristic curve, There is a problem that a holding current and hence a holding torque in the motor is required in case of fixing of a position, since the spindle drive (for example in the case of a PWG) does not automatically stop Because. In the case of PGW, in an HCA with a hollow wheel nut fixedly coupled to rotate integrally, in the case of an ideal rolling operation (in which the planetary gear is engaged As is the case with no slip phenomenon], a further reduction of the spindle pitch is achieved in which the limit can be chosen freely by changing the spindle diameter and / or the oil roller diameter. A decisive disadvantage of such actuators is that they can not be maintained in position where they require permanent retention current or in the event of a power failure / fault (e.g., cable break, plug release). When the clutch is pressed by the actuator, there is a great risk that the clutch will be closed unwantedly.

It is also known to use wrap springs for clutches, for example.

In the technical solution of the applicant, which has not been published yet, there is proposed an assembly for operating a vehicle clutch, particularly with a friction device having two or more parts rotatable relative to each other, in which case a relatively rotatable Between the parts, coil springs are arranged which affect the efficiency / friction upon relative rotation of the parts. In this case, the coil spring at least forms a wrap spring, which may be a single wrap spring, a double wrap spring, or a wrap-torsion spring. The double wrap spring described herein has two working areas arranged in series in the axial direction.

One common feature of the solutions known in the prior art is that the wrap spring is surrounded by the PWG-sleeve and has one friction surface for the sleeve and one friction surface for the hollow wheel of the PWG, respectively. Regarding the function, the hollow wheel as well as the sleeve were also implemented with steel. (Cold welding) which can lead to functional loss or failure of the assembly due to the steel-steel friction pair for friction places with high friction torque and also with regard to the lubricant, and the wear and tear caused thereby Can be expected to increase.

Furthermore, the hollow wheel is not driven in a shape-fitting manner, but rather is frictionally driven by a planetary roller. Such a structure is not important when the axial force is high because the hollow wheel is driven by the torques of the meteors which are larger than the torque of the friction element. What is problematic is a load situation in which the planetary drive torque applied to the hollow wheel is smaller than the braking torque of the friction element. In this case, the hollow wheel is not driven at all, and the planets slip with respect to the hollow wheel or with respect to the spindle depending on the friction ratio. The acting frictional force is likewise small due to low axial forces and only worsens the overall efficiency of the PWG, but such load situations occur frequently and over a longer distance / time interval, thereby distorting the rolling geometry Wear can be set for each region. In such a case, even if the drive torque is sufficiently large as compared with the friction element, the planets do not roll, whereby the wear is significantly enhanced by the higher force and can cause premature failure of the components.

It is an object of the present invention to provide an actuator in which an alternative positioning of a friction element is realized.

The above problem is solved by the features described in the characterizing part of the first patent claim.

Preferred embodiments are drawn from the dependent claims.

According to the present invention, an input element, preferably a rotor, a spindle, etc., which transmits torque, An output element that transmits a torque or a linear force, such as a spindle or a spindle nut; There is provided, in particular, an actuator for actuating a vehicle clutch, the unit being surrounded at least by region by the sleeve and for converting rotational motion into linear motion, in which case the different parts affect the efficiency To this end, a friction element is arranged between the part of the actuator driven in a rotational manner and the part of the actuator fixed to the frame / housing, in which case the friction element is arranged outside the sleeve according to the invention.

Preferably, in the present invention, the part lying inside the radial direction in the friction element rotates.

In particular, a unit for converting rotational motion into linear motion is a planetary roller screw drive, in which a plurality of planetary rollers engaged with a hollow wheel surrounding the planetary roller are engaged with the profile of the spindle, Parallel to the longitudinal axis of the hollow roller carrier and rotatably supported at both ends in the first and second planetary roller carriers freely about their own longitudinal axis and the planetary roller carrier is supported in a sleeve surrounding the hollow wheel And the sleeve and the planetary roller carrier supported in the sleeve are fixed in position in the axial direction and are fixedly connected to rotate integrally with the rotor of the drive unit And the sleeve has a rotor bearing with an inner ring and an outer ring And it is supported in a radial direction, in which case the spindle is fixed and supported to rotate integrally with respect to the stator housing and the drive unit, and the spindle has an axial stroke is performed when the planetary roller carrier and a rotor supported in a rotary sleeve.

According to the arrangement of the friction elements according to the present invention, the rolling situation is not disturbed and the provided installation space is not damaged.

In a preferred first embodiment, the friction element comprises a sleeve or rotor; And is arranged between the housing or the stator. The rotor and stator of one motor are generally extruded into plastic, and this situation has proven to be particularly advantageous for the friction mating part. The rotor and stator may be formed individually or both as a friction surface for the friction element. A particularly desirable fact is that the installation space is used axially offset relative to the rotor over as large a diameter as possible in order to keep the frictional force small.

In a second preferred embodiment, the friction element comprises a planetary roller carrier; And is arranged between the outer ring of the rotor-bearing or the PWG-bearing. In this case, the planetary roller carrier is preferably made of plastic.

In another preferred embodiment, friction elements are arranged between the inner ring and the outer ring of the rotor-bearing or PWG-bearing.

In particular, the friction element is a wrap spring.

The wrap spring is preferably formed of first and second wrap spring regions, preferably exactly two wrap spring regions. The two wrap spring areas are designed for high friction torque and low friction torque. The wrap spring areas are preferably offset radially offset relative to each other to reduce axial installation space demand.

Preferably, the friction mating part for the friction element is a plastic part. Alternatively, the friction mating portion may be coated with plastic. Formation from plastics or coating with plastics ensures lower wear.

Any other synchronized gear, such as a ball screw drive, a roller screw drive (RGT) or a motion thread, for example, may be used instead of the PWG.

The present invention provides an actuator in which alternative positioning of a friction element is performed without interfering with the rolling situation or damaging the installation space provided.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in more detail below with reference to an embodiment and the associated drawings, but is not limited to such embodiments and drawings.
Figure 1 shows a planetary roller screw drive (PWG) with a friction element according to the prior art,
2 shows an actuator according to the invention with a friction element arranged between the stator and the rotor of the electric motor,
3 shows an actuator according to the invention with a friction element arranged between the stator and the rotor of the motor in an alternative position,
Figure 4 shows an actuator according to the invention with a friction element arranged between the planet carrier and the outer ring of the rotor-bearing,
Figure 5 shows an actuator according to the invention with friction elements arranged between the inner ring and the outer ring of the rotor-bearing.

Figure 1 shows a planetary roller screw drive (PWG) with a friction element 7 according to the prior art. A plurality of planetary rollers (2) engaged with the hollow wheel (3) surrounding the planetary roller (2) are engaged with the profile of the spindle (1). The planetary rollers 2 advance axially parallel to the longitudinal axis A of the spindle 1 and are supported at their two ends in the first and second planetary roller carriers 4 and 5 respectively have. The planetary roller carriers 4 and 5 are fixedly supported in the sleeve 6 surrounding the hollow wheel 3 so as to rotate integrally with the sleeve. The sleeve 6 and the planetary roller carriers 4 and 5 are fixed in position in the axial direction and fixedly connected to rotate with the rotor of the driving unit not shown in the figure. When the planetary roller carriers 4, 5 supported in the sleeve 6 and the rotor rotate, the spindle 1 performs an axial stroke. In order to influence the efficiency when the different parts rotate relative to each other, a friction element is arranged between the hollow wheel 3 and the second planetary roller carrier 5, and a wrap spring 7 is arranged in the embodiment shown in the figure have. The wrap spring consists of a first wrap spring region 7.1 and a second wrap spring region 7.2 wherein the first wrap spring region 7.1 is interactively connected to the hollow wheel 3, The region (7.2) is interactively connected with the second planetary roller carrier (5). While the second planetary roller carrier 5 is fixed to the frame, the hollow wheel 3 is driven in a rotational manner. In this case, the rotational drive is performed from the planetary roller 2 in a frictional engagement manner.

2 to 5 , the actuator according to the present invention is shown as different embodiments. 2 to 5 is that a plurality of planetary rollers 2 engaged with the hollow wheel 3 surrounding the planetary roller 2 are engaged with the profile of the spindle 1. [ As in the prior art, the planetary rollers 2 advance axially parallel to the longitudinal axis A of the spindle 1, and at their two ends, the first planetary roller carrier 4 and the second planetary roller carrier 4 (Not shown). The planetary roller carriers 4 and 5 are fixedly supported in the sleeve 6 surrounding the hollow wheel 3 so as to rotate integrally with the sleeve. The sleeve 6 and the planetary roller carriers 4 and 5 are fixed in position in the axial direction and fixedly connected to rotate with the rotor R of the drive unit (shown in Figs. 2 and 3). When the planetary roller carriers 4, 5 and the rotor R supported in the sleeve 6 rotate, the spindle 1 performs an axial stroke. In order to influence the efficiency when the different parts rotate relative to each other, friction elements 7 are arranged in various positions in different embodiments. In all of the illustrated embodiments, the friction element is a wrap spring 7 consisting of a first wrap spring region 7.1 and a second wrap spring region 7.2.

2 shows an actuator according to the invention having a friction element 7 arranged between the stator S and the rotor R of the electric motor. The two wrap spring regions 7.1 and 7.2 are offset radially offset relative to each other. The first lap spring region (7.1) is an area lying radially outward of the two lap spring regions and is inter-connected as a friction mounter with the stator (S). The second lap spring region (7.2) is an area lying radially inward of the two lap spring regions and is interconnected as a friction mating portion with the rotor (R). The sleeve 6 of the PWG is supported in the radial direction through the rotor bearing 10. In this case, the rotor bearing 10 is on the same PWG side as the hollow wheel 3 when seen in the axial direction, while the friction elements 7 are arranged on the side of the PWG facing axially.

3 shows another embodiment of an actuator according to the present invention having a friction element 7 arranged between a stator S and a rotor R of a motor. In this embodiment also, the two wrap spring regions 7.1 and 7.2 are offset radially offset relative to each other. The first lap spring region (7.1) is an area lying radially outward of the two lap spring regions and is inter-connected as a friction mounter with the stator (S). The second lap spring region (7.2) is an area lying radially inward of the two lap spring regions and is interconnected as a friction mating portion with the rotor (R). The sleeve 6 of the PWG is supported in the radial direction through the rotor bearing 10. In this case, the rotor bearing 10 is on the side of the PWG facing axially in the same way as the hollow wheel 3, while the friction element 7 is on the side of the same PWG as the hollow wheel 3 Respectively.

Figure 4 shows an actuator according to the invention with a friction element 7 arranged between the planet carrier 5 and the outer ring 10.2 of the rotor-bearing 10. [ The rotor-bearing 10 is supported in an inner ring 10.1 and an outer ring 10.2, in which case the inner ring 10.1 is formed as part of the sleeve 6 in the illustrated embodiment. The first wrap spring region 7.1 and the second wrap spring region 7.2 are offset offset not only radially but also axially with respect to each other. The first lap spring region (7.1) is the radially outermost region of the two wrap spring regions and is operatively connected to the outer ring (10.2) of the rotor bearing (10) as a friction mating portion. The second wrap spring region (7.2) is an area lying radially inward of the two wrap spring regions and is interconnected as a friction mating portion with the second planetary roller carrier (5).

The embodiment shown in Fig. 5 shows an actuator according to the invention having a friction element 7 arranged between the inner ring 10.1 of the rotor-bearing 10 and the outer ring 10.2. In this embodiment, the rotor-bearing 10 is supported in the inner ring 10.1 and the outer ring 10.2, in which case the inner ring 10.1 is formed as part of the sleeve 6. The first wrap spring region (7.1) and the second wrap spring region (7.2) are offset radially offset relative to each other. The first lap spring region (7.1) is the radially outermost region of the two wrap spring regions and is operatively connected to the outer ring (10.2) of the rotor bearing (10) as a friction mating portion. The second lap spring region (7.2) is an area lying radially inward of the two lap spring regions and is interconnected with the inner ring (10.1) of the rotor bearing (10) as a friction mating portion.

1: Spindle
2: planetary roller
3: hollow wheel
4: first planetary roller carrier
5: Second planetary roller carrier
6: Sleeve
7: Friction element
7.1: First wrap spring area
7.2: second wrap spring area
8: Housing
9: Sensor magnet
10: Rotor bearing
10.1: Inner ring of rotor bearing
10.2: Outer ring of rotor bearing
A: The axle of the spindle
R: Rotor
S: stator

Claims (10)

An input element for transmitting torque, preferably a rotor, a spindle, etc.; An output element that transmits a torque or a linear force, such as a spindle or a spindle nut; An actuator for actuating a vehicle clutch, in particular at least in regions surrounded by sleeves 6 and having a unit for converting rotational motion into linear motion, in order to influence the efficiency when different parts rotate relatively, A friction element (7) is arranged between a part of an actuator driven in a rotational manner and a part of an actuator fixed to the frame / housing,
Characterized in that the friction elements (7) are arranged outside the sleeve (6). 2. Actuator according to claim 1, characterized in that the part lying radially in the friction element (7) rotates. A planetary roller system according to claim 1 or 2, wherein the unit for converting rotational motion into linear motion is a planetary roller screw drive (PWG), comprising a plurality of planetary rollers The planetary roller 2 meshes with the profile of the spindle 1 and the planetary roller 2 travels axially parallel to the longitudinal axis A of the spindle 1 and the first and second planetary roller carriers 4 And 5 are freely rotatably supported about their own longitudinal axis and the planetary roller carriers 4 and 5 are integrally supported with respect to the sleeve 6 in a sleeve 6 surrounding the hollow wheel 3 And is a component of the sleeve 6 and the sleeve 6 and the planetary roller carriers 4 and 5 supported in the sleeve are fixed in the axial direction and are rotatably supported by the rotor R And the sleeve 6 is fixedly connected to the inner ring 10 The spindle 2 is supported in a radial direction through a rotor bearing 10 having an outer ring 10. 1 and an outer ring 10. The spindle 2 is fixedly secured to the housing 8 and the stator S of the drive unit, , And the spindle (2) performs an axial stroke when the planetary roller carriers (4, 5) and the rotor (R) supported in the sleeve (6) rotate. 4. A device according to claim 3, characterized in that the friction element (7) comprises a sleeve (6) or a rotor (R); Is arranged between the housing (8) or the stator (S). 4. A device according to claim 3, characterized in that the friction element (7) comprises a planetary roller carrier (4, 5); And the outer ring (10.2) of the rotor-bearing or PWG-bearing. 4. An actuator according to claim 3, characterized in that the friction element (7) is arranged between the inner ring (10.1) and the outer ring (10.2) of the rotor-bearing or PWG-bearing. 7. An actuator according to any one of claims 1 to 6, characterized in that the friction element (7) is a wrap spring. 8. A method according to claim 7, characterized in that the wrap spring is formed from a first wrap spring region (7.1) and a second wrap spring region (7.2), preferably exactly two wrap spring regions (7.1, 7.2) Actuator. 9. The actuator according to claim 8, characterized in that the wrap spring regions (7.1, 7.2) are offset radially offset with respect to each other. 10. An actuator according to any one of the preceding claims, characterized in that the friction mating portion for the friction element (7) is a plastic part and / or is coated with plastic.

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