WO2016155724A1

WO2016155724A1 - Planetary roller screw drive (prsd) and actuator having a planetary roller screw drive

Info

Publication number: WO2016155724A1
Application number: PCT/DE2016/200139
Authority: WO
Inventors: Lars Schumann; Lászlo Mán; Peter Greb
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2015-04-01
Filing date: 2016-03-15
Publication date: 2016-10-06
Also published as: CN107407343B; KR102594443B1; CN107407343A; DE102015205963B3; KR20170133401A; DE112016001577A5

Abstract

The planetary roller screw drive (PRSD (1)) is intended in particular for the actuation of a clutch of a vehicle, wherein the planets have a planet geometry for force introduction in particular from one side, such that a plurality of planetary rollers (3) are engaged in a first longitudinal region with a profiling (P2) of a spindle (2) by way of their profilings (P3.1, P3.2) and the profilings (P3.2) of the planetary rollers (3) mesh in a second longitudinal region with a profiling (P4) of a ring gear (4) encircling the planetary rollers (3), wherein the profilings (P2, P3, P4) are formed in the manner of a screw thread with elevations and grooves extending therebetween, and wherein the planetary rollers (3) extend axially parallel to the spindle (2) and are positioned so as to be freely rotatable about their own longitudinal axis at both ends in planetary roller carriers, and the planetary roller carriers are supported in a rotationally fixed manner. According to the invention, the planetary rollers (3) have, at only a first end in the vicinity of the second longitudinal region, a bearing journal (7) by way of which they are mounted in the first planetary roller carrier, while the planetary rollers (3) are supported in the second planetary roller carrier at their second end by way of their profilings (P3.1). Likewise according to the invention is an actuator, in particular for actuating a clutch in the drive train of a vehicle having a planetary roller screw drive according to the invention.

Description

Planetary roller screw drive (PWG) and actuator with a planetary roller screw drive

The invention relates to a Planetenwälzgewindetrieb (PWG) of an actuator according to the preamble of the first claim and an actuator with a Planetenwälzgewindetrieb. Planetary rolling screw drives (PWG) (also referred to as planetary roller screw drives or as planetary roller screw spindles) have been state of the art for many years and are described, for example, in DD 0277308 A5. From DE 10 2010 047 800 A1, for example, a planetary roller screw drive is known which is contained in a hydrostatic actuator in the form of a hydrostatic clutch actuator in order to convert a rotational movement generated by means of an electric motor into an axial movement. A Planetenwälzgewindetrieb, with a threaded spindle, and arranged with a threaded spindle on the nut, and with a plurality of circumferentially distributed between the threaded spindle and the nut arranged planetary, which are arranged abradably on the inner circumference of the nut and on the outer circumference of the threaded spindle, is Publication DE 10 2010 01 1 820 A1. In this solution, a biasing means for the planet is provided, wherein the nut has two mutually axially movable male parts, and wherein the biasing means comprises a spring member urged against the one nut member. The nut takes on two functions: on the one hand, it is gear part and on the other hand, it is part of the pretensioner. DE 10 2014 202 1 18 A1 describes an actuator with Planetenwälzgewindetrieb in which the axial stroke of the spindle is induced by a rotatably connected with sleeve and planetary roller carriers in connection rotor.

In a not yet published patent application, a PWG is proposed with such asymmetric planetary rollers that they mesh in exactly one length range with a ring gear. The bearing of the planetary rollers takes place on both sides at the ends of the planetary rollers formed bearing journals, which are mounted in planetary roller carriers.

It is also common to other solutions known from the prior art that bearing pins are formed at both ends of the planetary rollers. This results in a correspondingly large space requirement.

The object of the invention is to develop a Planetenwälzgewindetrieb with mainly one-sided loading direction, in which a reduced axial length is made possible, and to provide an actuator with a corresponding Planetenwälzgewindetrieb. This object is achieved with the characterizing features of the first and eighth claim.

Advantageous embodiments emerge from the subclaims.

The planetary roller screw drive (PWG) is provided in particular for the actuation of a clutch of a vehicle, the planets having a planetary geometry for a particular unilateral force introduction, such that with a profiling of a spindle in a first length range, several planetary rollers are engaged with their profiles and the profiles of the planetary rollers in a second length range with a profiling of a ring gear surrounding the planetary rollers, the profiles are formed like a winding with projections and extending therebetween grooves and the planetary rollers axially parallel to the spindle and freely rotatable at both ends in planetary roller carriers are positioned about their own longitudinal axis, and wherein the planetary roller supports are rotatably supported. According to the invention, the planetary rollers at only one first end in the vicinity of the second length range on a bearing journal, with welhern they are stored in the first planetary roller carrier, while the planetary rollers are supported at their second end with their profiles in the second planetary roller carrier. The planetary rollers themselves are thus formed asymmetrically.

In particular, the first length range (L- ₁ ) is different from the second length range (L ₂ ).

The planetary rollers and the ring gear surrounding the planetary rollers are surrounded by an outer sleeve, which is formed in two parts, wherein a part receives the first planetary roller carrier and a second part forms the second planetary roller carrier.

Between the outer sleeve and the ring gear, a friction device in the form of a wrap spring is preferably arranged.

In the main force direction, the radial support of the planetary rollers is proportional to the profi Herten ring gear area, as well as a first planetary roller carrier, in which the bearing journal is mounted at the first end of the planetary rollers.

In the opposite direction of force, at the end opposite the bearing journal of the planetary rollers, the radial bearing of the planetary rollers in the first longitudinal region via the elevations of the profiles of the planetary rollers. Thus, on this side of the planetary rollers can be dispensed with an additional journal.

In particular, the planetary roller carrier is at least partially radially adjacent to the planetary rollers at the second end of the planetary rollers opposite the first end of the planetary rollers. In a preferred embodiment, the elevations of the profiles of the planetary rollers in the first length range are flattened. This embodiment leads to a surface load in the bearing, which has proven to be advantageous over rounded elevations of the profiles of the planetary roles. The flattening can be done for example via a turning and / or grinding process.

The first end opposite the second end of the planetary rollers is preferably in operative connection with an axial securing plate. The small or rarely occurring axial force in the opposite direction to the main force direction is introduced from the front side of the planetary rollers in this axial locking plate. The axial securing plate is preferably metallic and can be made significantly thinner than the planet carrier with journal bearing on the opposite side.

The planetary rollers and / or the axial securing plate are preferably rounded at their contact surface. This advantageously ensures a reduced drilling friction at the contact surface.

Also according to the invention is an actuator, in particular for actuating a clutch in the drive train of a vehicle with a Planetenwälzgewindetrieb invention.

The inventive solution advantageously reduces the axial installation space of the planetary roller screw drive

The invention will be explained in more detail with reference to an embodiment and associated drawings, without being limited to this. Show it:

Figure 1: a longitudinal section through a PWG according to the prior art with both sides

Journals,

Figure 2: a longitudinal section through an inventive PWG.

1 shows a longitudinal section through a PWG 1 according to the prior art. The planetary rollers 3 engage in a first length range L- ₁ with a first region of their profile P _{3 1} in the profiling P _{2 of} the spindle 2 a. In a second length range L _2, the planetary rollers 3 engage with a second area of their profiling P _{3 2} in the profiling P ₄ of the ring gear 4 encircling the planetary rollers 3. The planetary rollers 3 have at both ends bearing journals 7, with which they are in planetary roller carriers 5, 6 axially and radially are supported. The planetary rollers 3 and the planetary rollers 3 surrounding ring gear 4 are surrounded by an outer sleeve 9, which is formed in two parts, wherein a part receives the first planetary roller 5 and a second part forms the second planetary roller carrier 6. Between the outer sleeve 9 and the ring gear 4, a friction device in the form of a wrap spring 10 is arranged.

FIG. 2 shows a longitudinal section through a PWG 1 according to the invention. The planetary rollers 3 engage in a first length range L- ₁ with a first region of their profile P _{3 1} in the profiling P _{2 of} the spindle 2 a. In a second length range L ₂ , the planetary rollers 3 engage with a second region of their profiling P _{3 2} in the profiling P ₄ of the ring gear 4 encircling the planetary rollers 3. According to the invention, a bearing pin 7 is formed only at the first end of the planetary rollers 3. This is supported for the axial and radial mounting of the planetary rollers 3 in the main force direction in a first planetary roller carrier 5. A part of the radial support of the planetary rollers 3 in the main force direction is also realized via the ring gear 4 in the second length range L ₂ . At the opposite end no bearing pin is formed. The radial support in the direction opposite to the main force direction force direction via the surveys of the profiles P _{3 1 of} the planetary rollers 3 in a first part of the first length range Lu Li. In this part Lu of the first length range L-1, a second planetary roller carrier 6 is arranged radially adjacent to the planetary rollers 3, via which the radial support takes place. In the first length region Li, the elevations of the profilings of the planetary rollers 3 are flattened, which leads to a surface load in the bearing point. In the illustrated embodiment, both the planetary rollers 3 and the axial securing plate 8 at the point of contact of the planetary rollers 3 to the axial securing plate 8 are flat educated. The planetary rollers 3 and the planetary rollers 3 surrounding ring gear 4 are surrounded by an outer sleeve 9, which is formed in two parts, wherein a part receives the first planetary roller 5 and a second part forms the second planetary roller carrier 6. Between the outer sleeve 9 and the ring gear 4, a friction device in the form of a wrap spring 10 is arranged. LIST OF REFERENCE NUMBERS

1 planetary roller screw drive

2 spindle

3 planetary role

4 ring gear

5 first planetary roller carrier

6 second planetary roller carrier

7 journals

8 axial securing plate

9 outer sleeve

10 wrap spring

Li first length range

L-i .1 first part of the first length range

L ₂ second length range

P ₂ profiling of the spindle

P3.1 Profiling of the planetary roller in engagement with the spindle

P3.2 profiling of the planetary roller in engagement with the ring gear

P ₄ profiling of the ring gear

Claims

claims

Planetenwälzgewindetrieb (PWG) (1), in particular for the actuation of a clutch of a vehicle, wherein with a profiling (P ₂ ) of a spindle (2) in a first length range (L-ι) a plurality of planetary rollers (3) with their profiles (P _{3rd 1} , P _{3 2} ) engage and the profiles (P3.2) of the planetary rollers (3) in a second length range (L ₂ ) with a profiling (P ₄ ) of the planetary rollers (3) surrounding ring gear (4), wherein the profilings (P ₂ , P3.1, P3.2, P ₄ ) are formed in a thread-like manner with elevations and grooves extending therebetween, and wherein the planetary rollers (3) extend parallel to the axis of the spindle (2) and at both ends in a first and a second planetary roller carriers (5, 6) are freely rotatably positioned about their own longitudinal axis, and wherein the planetary roller carriers (5, 6) are rotatably supported, characterized in that the planetary rollers (3) at only a first end in the vicinity of the second length nbereiches (L ₂ ) have a bearing pin (7) and are mounted with the bearing pin (7) in the first planetary roller carrier (5) and that the planetary rollers (3) at its second end with their profiles (P3.1) in the second planetary roller carrier (6) are supported.

Planetenwälzgewindetrieb (1) according to claim 1, characterized in that the first length range (L-ι) from the second length range (L ₂ ) is different.

Planetenwälzgewindetrieb (1) according to one of claims 1 or 2, characterized in that the radial bearing of the planetary rollers (3) in a first part (Lu) of the first length range (L-ι) on the surveys of the profiles (P3.1) of Planetary rollers (3) takes place.

Planetenwälzgewindetrieb (1) according to one of claims 1 to 3, characterized in that the second planetary roller carrier (6) at the first end of the planetary rollers (3) opposite the second end of the planetary rollers (3) at least partially radially adjacent to the planetary rollers (3) lies.

Planetenwälzgewindetrieb (1) according to one of claims 1 to 4, characterized in that the elevations of the profilings (P3.1) of the planetary rollers (3) in the first longitudinal region (Li) are flattened.

6. Planetenwälzgewindetrieb (1) according to one of claims 1 to 5, characterized in that the planetary rollers (3) frontally at its second end opposite the first end with an axial securing plate (8) are in operative connection.

7. Planetenwälzgewindetrieb (1) according to claim 6, characterized in that the planetary rollers (3) and / or the Axialsicherungsblech (8) are formed rounded at their contact surface.

8. Actuator, in particular for actuating a clutch in the drive train of a vehicle with a Planetenwälzgewindetrieb (1) according to one of claims 1 to 7.