Skf Nova Ab

Skf Industrial Trading & Development Company, B.v.

Ab Skf Nova

Sven W Nilsson

Bengt Lundgren

In a screw and nut driving device with low internal friction, e.g. a ball nut mechanism, irreversibility is effected in a simple and efficient manner when the nut is rotatably driven and enclosed by an annular space in which a helical spring is arranged in such a manner that its ends are acted upon by the driving force from the external driving source, thus that the spring can rotate freely in the space. When the external driving source is disconnected and the nut, due to axial load is subjected to a torque, the ends of the spring are acted upon thus that the spring is deformed to friction locking against a non-rotating surface, whereby the nut is prevented from rotation.

Irreversible screw and nut driving device

In a device for bringing about rotational braking in a screw and nut device incorporating a nut, which is rotatable and displaceable relative to a threaded bar, and a helical spring enclosing the bar, which spring at braking is clamped against the bar, for effecting a big braking moment and a small wear in the thread of the bar, there is arranged a helical element with a loose fit in the thread groove of the bar, which element extends radially outside the thread flank tip. The helical spring is futhermore arranged with radial pretension of the thread flank tip between the winding turns of the helical element.

Screw and nut device equipped with a rotation brake

In a device for producing self-locking properties of a screw and nut device the nut co-operates with a torque-transmitting part which is rotatable in relation to the nut. Torque is transmitted via a portion on the torque-transmitting part, which portion is arranged in a space between two opposing surfaces on the nut. A helical spring is arranged in a thread around a threaded shaft and has an end portion inserted into the space. The helical portion of the spring has a loose fit in the thread when the nut is driven by the part, whereas the spring is contracted against the shaft when the end portion contacts one of the opposing surfaces of the nut and thereby brakes the rotation if the nut tends to be rotated by an axial load on the nut and the part is disconnected.

Screw and nut drive with rotation lock

In a motion transmitting mechanism comprising a linearly moveable member (3) operating to and from an end stop, a compressible spring (9) is arranged between the linearly moveable member (5) and a supporting surface (10), whereby the spring is compressed when the member (5) approaches the end position and gives a force on the member (5) directed away from the supporting surface when the member is in its end position.

Motion transmitting mechanism

An element intended for connection to a shaft arranged in a bore in the element comprises two elastically deformable portions created by providing slots perpendicular and parallel to the axis of the bore, respectively. The portions each comprise a part of the wall of the bore and are arranged symmetrically with respect to the bore. Screws are used for deforming the portions so that a shaft situated in the bore is clamped to the element.

Clamping joint

The invention relates to a device for performing rotational movement and comprises a rotatably element such as a cog-sector (3) or the like, arranged in a housing (1). The sector can easily be connected to rotatable machine elements of various kinds by being provided with an easily exchangeable coupling element (7) which can be displaced axially through a bore in the sector and through two bearings (8, 9) and be detachably fastened to the cog-sector by e.g. screws (14, 15) provided in threaded bores in the sector and abutting radially directed support surfaces in recesses in the element (7) between the bearing surfaces of the bearings (8, 9).

Coupling member for mechanism for converting linear to rotary motion

The invention relates to an apparatus incorporating a planetary gear set with a shaft (7) connected to a planet wheel support (6), and a shaft (8) connected to a sun wheel (5), one of the shafts (8) being connected to a rotor in a device (9) for providing a torque. In order to be able to use the apparatus in a favorable manner in for example a servo assisted system with a steering wheel (10) and a steering member actuated by the steering wheel via a step-up gear, the stator part of the device (9) for providing a torque is connected to the other one of the shafts (7) in the planetary gear so that this shaft takes up the reactive torque which is established in the device during operation.

Apparatus with a planetary gear set

Worm gear

A planetary gearing system comprising a planet carrier and planet gear wheels and planet friction wheels supported on planet wheel shafts on said planet carrier, said planet gear wheels cooperating with a gear ring encircling them and a sun gear wheel, said planet friction wheel cooperating with a friction ring circumscribing them and with a sun friction wheel, a housing enclosing the planet gearing system, said friction ring or ring gear being radially movable relative to said housing and means for mounting said gear ring and/or friction ring 20 in said housing by means providing an adjustable friction force so that they rotate in the housing when subjected to a torque exceeding a torque determined by said friction force.

Planetary gearing system

A gear comprises two co-operating gear wheels (1,2), one (2) of which, in operation, performing a conical pendulating movement (nutation). One gear wheel (2) is non-rotationally connected to an adjacent element (8) by resilient elongated members (9), preferably extending mainly in the circumferential direction of the gear wheel between two supports (10,11) arranged diametrically on the gear wheel and two supports (12,13) arranged diametrically on the adjacent element and offset about 90.degree. in relation to the first mentioned supports. The resilient members keep the gear wheel (2) non-rotationally in the adjacent element and permits said pendulating movement of the gear wheel.

Gear

The invention relates to a mechanism with a screw (1) and a nut made of two sheet metal halves (4, 5) and having two complementary helical grooves (12, 13, 14, 15) which constitute raceways for a number of rolling bodies (16, 17) circulating in at least one closed loop around the screw. In order to provide a mechanism with small dimensions and good circulation conditions for the rolling bodies, the groove in a cylindrical portion of the nut surrounding the screw is provided with a recessed portion (18, 19) with a pitch that is different from the rest of the groove, said recessed portion constituting a return portion of the closed loop over a ridge (3) between two adjacent groove turns in the screw.

Screw and nut mechanism

A device for transferring a rotational motion into a longitudinal movement or vice versa. The device comprises a cylindrical shaft (1), a sleeve (2) enclosing the shaft and displaceable along and rotatable relative thereto. A cage (3) is mounted between the sleeve and shaft for axial movement with the sleeve as a unit. A plurality of rolling bodies (4) are mounted in elongated apertures in the cage and are arranged during operation to roll in a closed track around the shaft. The track has a helical portion and a recirculation portion. The rolling bodies contact the shaft and the sleeve in the helical portion and are axially moveable in the recirculation portion. Cam profile members (5, 6) are arranged at the ends of the cage for actuating the rolling bodies in the recirculation portion. The rolling bodies are arranged in the apertures in the cage in such a manner that their axes form an angle to the cylindrical shaft, this angle corresponding to the pitch angle of the helical form of the helical track portion.

Device for transferring a rotational motion into a longitudinal movement

A device for transforming a rotational movement into a linear movement. The device comprises a retainer and a shaft extending through the retainer which are mounted for movement relative to one another. A plurality of annular bearing members, in the illustrated embodiment, comprising ball bearings, circumscribes the shaft and engages the same at axially spaced locations. The bearings are mounted for tilting movement relative to the shaft. The outer ring of each of the bearing assemblies is supportd in a housing and each housing has an external surface section defined by a circular arc having a center on the rotational axis of the housing which slidingly engages internal walls of the retainer of complementary form.

Device for transforming a rotational movement into a linear movement

A mechanism for transferring a rotary motion into an axial motion. The assembly includes a shaft having a smooth, cylindrical envelope surface, a retainer enclosing the shaft and rotatable relative the shaft. A plurality of bearing housings with bearing seats inclined towards the shaft are arranged in the retainer. Bearings having outer and inner race rings are arranged in the bearing seats. The bore diameter of the inner race rings, which are arranged to enclose the shaft, are larger than the diameter of the shaft. The bearing seats are designed completely to enclose the outer race rings of the bearings. The retainer has a recess having opposing sidewalls defining guide surfaces. The bearing housings are slidable in and guided by the sidewalls of the recess for displacement substantially perpendicularly to the shaft. The bearing housings are subjected to a force in the direction of displacement so as to urge the inner race rings of the bearings against the envelope surface of the shaft.

Mechanism for transferring a rotary motion into an axial motion

A planetary gear system comprising housing, an input shaft at one end and an output shaft at the opposite end and transmission means drivingly connecting the shafts to one another. The transmission means includes a planet support having at least two planet wheel journals mounted therein. At least one of the journals mounts a planet friction wheel adapted to contact a friction ring having at least an elastically deformable portion. Means is provided for adjusting the pressure applying relation between the planet friction wheel and the elastically deformable portion of the friction ring. This arrangement provides a multiple step gear system wherein the play in the system is minimized and the system operates at low noise levels.

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Partille, Sweden

Sven W Nilsson