DE3138913C1

DE3138913C1 - Recirculating-ball screw

Info

Publication number: DE3138913C1
Application number: DE19813138913
Authority: DE
Inventors: Helmut 8962 Pfronten Fritz; Peter Schneider
Original assignee: Maho Werkzeugmaschinenbau Babel & Co 8962 Pfronten De; Maho Werkzeugmaschinenbau Babel and Co
Current assignee: Alois Berger & Co Praezisions-Maschinenbaute GmbH
Priority date: 1981-09-30
Filing date: 1981-09-30
Publication date: 1983-03-31

Abstract

The invention relates to a recirculating-ball screw with a recirculating-ball nut (3) and one or more ball return elements (6), each inserted radially from the outside in a radial opening in the recirculating-ball nut (3), for transferring balls (5) from one rolling track to the other. To obtain uniform transfer of the balls from one rolling track to the other with less wear than known designs, especially wear to the entry and exit regions of the ball return element, the ball return element (6) is fixed adjustably in the radial opening of the recirculating-ball nut (3; 11) by means of a screw. This provides the possibility of simple exchange of the ball return element (6) and very fine adjustment and adaptation to the course of the corresponding ball rolling tracks (1, 4) in the screw (1) and the recirculating-ball nut (3). <IMAGE>

Description

Im folgenden werden die Ausführungsbeispiele der Erfindung anhand der Zeichnung im einzelnen beschrieben. Es zeigt F i g 1 eine erste Ausführungsform einer bei der erfindungsgemäßen Kugelrollspindel verwendeten Ku- In the following, the exemplary embodiments of the invention are based on the drawing described in detail. FIG. 1 shows a first embodiment a Ku- used in the ball screw according to the invention

gelumlaufmutter in teilgeschnittener Seitenansicht; F i g. 2 eine Seitenansicht auf ein Kugelrückführglied mit einer Stellschraube; Fig.3 eine Draufsicht auf das Kugelrückführglied und die Stellschraube nach F i g. 2; F i g. 4 eine andere Ausführungsform einer Kugelumlaufmutter; F i g. 5 die Positionierung eines Kugelrückführglieds mit Stellschraube in der radialen Öffnung einer Kugelumlaufmutter, und zwar im Längsschnitt des Kugelrückführglieds.gel recirculation nut in partially sectioned side view; F i g. 2 one Side view of a ball return member with an adjusting screw; Fig. 3 is a plan view on the ball return element and the adjusting screw according to FIG. 2; F i g. 4 another Embodiment of a recirculating ball nut; F i g. 5 the positioning of a ball return member with adjusting screw in the radial opening of a recirculating ball nut, namely in longitudinal section of the ball return member.

Die in F i g. 1 dargestellte Kugelrollspindel besteht aus einer lediglich schematisch dargestellten Spindel 1 mit Rollgängen 2 von etwa halbzylindrischem Querschnitt sowie aus der Kugelumlaufmutter 3, in deren Innenwand ebenfalls schraubenlinienförmig verlaufende Rollgänge 4 von etwa halbzylindrischem Querschnitt ausgebildet sind. Die jeweils halbzylindrischen Rollgänge 2 und 4 in der Spindel und in der Kugelumlaufmutter ergänzen sich zu etwa zylindrischen Rollgängen, in denen eine Vielzahl von Kugeln 5 zu mehreren Reihen nebeneinander angeordnet sind. Die Überführung der Kugeln von einem Rollgang zum nächsten erfolgt mittels eines in F i g. 1 schematisch und kleinschraffiert dargestellten Kugelrückführglieds 6, welches in eine Radialöffnung von entsprechender Form in der Kugelumlaufmutter 3 hinsichtlich seiner Ausrichtung einstellbar festgelegt ist. The in F i g. 1 shown ball screw consists of one only schematically illustrated spindle 1 with roller tables 2 of approximately semi-cylindrical Cross-section as well as from the recirculating ball nut 3, also helically in the inner wall extending roller tables 4 are formed of approximately semi-cylindrical cross-section. The semi-cylindrical roller tables 2 and 4 in the spindle and in the recirculating ball nut complement each other to form roughly cylindrical roller tables in which a large number of balls 5 are arranged side by side in several rows. The transfer of the balls from one roller table to the next takes place by means of one in FIG. 1 schematically and with small hatching shown ball return member 6, which in a radial opening of the corresponding Shape in the recirculating ball nut 3 set adjustable in terms of its orientation is.

Das in den F i g. 2, 3 im einzelnen dargestellte Kugelrückführglied 6 hat eine langgestreckte Form mit kreisförmig abgerundeten Enden, einer ebenen Oberseite 7 und bogenförmigen Unterkanten 8. In diesem Kugelrückführglied 6 ist ein nach unten offener Kugelrückführkanal 9 ausgearbeitet, der in Draufsicht die in F i g. 3 ersichtliche S-Form hat und im Kugelrückführglied 6 in Längsrichtung verläuft. Gemäß F i g. 2 nimmt die radiale Tiefe diese Kugelrückführkanals 9 zur Mitte hin ständig zu Auf der Oberfläche 7 dieses Kugelrückführglieds 6 stützt sich eine Stellschraube 10 ab, die als Stiftschraube mit Feingewinde ausgebildet ist. Der Durchmesser dieser Stiftschraube 10 ist größer als die Breite des Kugelrückführglieds 6, so daß jeweils zwei Gewindesegmente der Stiftschraube 10 über die beiden ebenen Seitenwandungen des Kugelrückführglieds hervorstehen. Die in der Kugelumlaufmutter 3 vorgesehene Radialöffnung hat die Form der Außenkontur der in Fig. 3 dargestellten Baugruppe aus Kugelrückführglied 6 und Stell- bzw. Stiftschraube 10. The in the F i g. 2, 3 ball return member shown in detail 6 has an elongated shape with circular rounded ends, a flat one Top 7 and arcuate lower edges 8. In this ball return member 6 is a downwardly open ball return channel 9 worked out, which in plan view the in Fig. 3 has the S-shape and in the ball return member 6 in the longitudinal direction runs. According to FIG. 2 takes the radial depth of this ball return channel 9 to Center constantly closed on the surface 7 of this ball return member 6 is supported an adjusting screw 10, which is designed as a stud with a fine thread. The diameter of this stud 10 is greater than the width of the ball return member 6, so that in each case two thread segments of the stud screw 10 over the two flat ones Side walls of the ball return member protrude. The one in the recirculating ball nut 3 provided radial opening has the shape of the outer contour of that shown in FIG Assembly of ball return element 6 and adjusting screw or stud screw 10.

Die in Fig. 4 dargestellte Kugelumlaufmutter 11 entspricht hinsichtlich der Kugelrückführung von einem Rollgang 4 zum anderen der in Fig. 1 dargestellten Ausführung. Sie weist jedoch an einem Ende einen Flansch 12 zur Drehmomentübertragung und zusätzlich eine Einrichtung 13 zur Beseitigung des Spiels der Kugeln in den Rollgängen auf. Diese Einrichtung besteht aus einem geschliffenen Ring 13, der an den beiden Teilen 14, 15 der Kugelumlaufmutter mit seinen jeweiligen Stirnflächen befestigt ist und dessen Breite geringfügig kleiner als die Teilung bzw. die Ganghöhe eines Rollganges ist, so daß die Kugeln ständig an den Wänden des Rollganges spiellos abrollen. Wie ersichtlich, sind dieser Ring 13 und die beiden Teile 14, 15 durch eine Paßfeder 16 abgedeckt und gegen Verdrehung gesichert In F i g 5 ist die Lage der einzelnen Bauteile bei einer zusammengebauten Kugelrollspindel dargestellt. Insbesondere läßt sich in dieser Figur die radiale Überführung der Kugeln 5 von einem in Vollinien dargestellten Rollgang la, 4a in einen - gestrichelt eingezeichneten benachbarten Rollgang l b, 4b entnehmen. Um das Rückführglied 6 und auch die Stellschraube 10 in ihrer eingestellten Lage zu sichern, ist der Freiraum der Radialöffnung bündig mit der Außenwand der Kugelumlaufmutter 3; 11 mit einem Kunstharz 17 vollständig ausgegossen, was auch den Vorteil einer wirksamen Abdichtung der beiden Teile 6, 10 und der Kugeln 5 ergibt, was insbesondere im Hinblick auf einen wirksamen Korrosionsschutz von Bedeutung ist Diese Kunstharzfüllung 17 behindert den Ausbau der Stellschraube 10 und des Kugelrückführglieds 6 nicht, da sie vordem Ausbau herausgebrochen werden kann. The recirculating ball nut 11 shown in Fig. 4 corresponds with respect to the ball return from one roller table 4 to the other of the one shown in FIG Execution. However, at one end it has a flange 12 for transmitting torque and in addition a device 13 for eliminating the play of the balls in the Roller tables on. This device consists of a ground ring 13, which is attached to the two parts 14, 15 of the recirculating ball nut with its respective end faces is attached and its width is slightly smaller than the pitch or the pitch of a roller table, so that the balls are constantly on the walls of the roller table without play roll off. As can be seen, this ring 13 and the two parts 14, 15 are through a feather key 16 is covered and secured against rotation. FIG. 5 shows the position of the individual components in an assembled ball screw. In particular, the radial transfer of the balls 5 from a roller table la, 4a shown in solid lines in a - shown in dashed lines Remove adjacent roller table l b, 4b. To the feedback member 6 and also the adjusting screw To secure 10 in their set position, the free space of the radial opening is flush with the outer wall of the recirculating ball nut 3; 11 with a synthetic resin 17 completely poured out, which also has the advantage of an effective sealing of the two parts 6, 10 and the balls 5 results, which is particularly important with regard to effective protection against corrosion This synthetic resin filling 17 hinders the removal of the adjusting screw 10 and the ball return member 6, since they are broken out before removal can.

Für jede gesonderte Reihe an Kugeln wird jeweils ein Kugelrückführglied 6 mit einer Stellmutter 10 verwendet, die in gleichmäßiger Winkelversetzung in entsprechenden radialen Öffnungen der Kugelumlaufmutter angeordnet sind. Die in F i g. 1 dargestellte Winkelversetzung der beiden Kugelrückführglieder ist aus Gründen einer klaren Darstellung zu gering gewählt Bei Verwendung von z.B. drei Kugelrückführungen sollte die Winkelversetzung jeweils 120° betragen. One ball return member is used for each separate row of balls 6 used with an adjusting nut 10, which is in uniform angular displacement in corresponding radial openings of the recirculating ball nut are arranged. The in F i g. 1 shown Angular displacement of the two ball return members is for the sake of clarity too low When using e.g. three ball return systems, the angular offset should each be 120 °.

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Claims

Claim: Ball screw spindle with recirculating ball nut and at least one adjustable in a radial opening of the recirculating ball nut and through a Adhesive fixable ball return member for transferring the balls from a Roller table to the other, characterized in that the ball return member (6) a elongated shape with a flat surface (7) and a three-dimensional S-shaped Has return channel (9) on the underside and by means of an adjusting screw (10) is set in the radial opening of the recirculating ball nut (3; 11), the diameter of which is greater than the width of the ball return member, and that the clearances of the radial The opening in the recirculating ball nut is tightly filled with the hardening adhesive (17) are.

The invention relates to a ball screw in the preamble of Claim specified genus.

Ball waste spindles are used in mechanical engineering, precision engineering and Optics used in ever increasing numbers, namely z. B. to implement Rotational movements into translatory movements and vice versa. A special advantage of ball screw spindles compared to conventional - spindle drives is in the better Ease of movement of the two relatively movable components This results from the rolling motion of a multitude of balls running in a helical shape Roller tables are arranged, which in the spindle itself as well as in the recirculating ball nut Are arranged in alignment with one another and usually one approximately semicircular each Have cross-section. One of the essentials for the practical use of ball screws The criteria are the type of ball transfer from one roller table to the other.

From DE-PS 2437 497, for example, a ball guide is known, which consists of a cylindrical axial channel arranged in the recirculating ball nut. This axial channel extending approximately over the entire length of the recirculating ball nut is by screwed on - and thus detachable - caps at both ends closed, in which to feed and discharge the balls to the individual roller tables Arcuate channels are incorporated, which at one end in the axial channel the recirculating ball nut and open into one of the roller tables at the other end. These The type of ball return is due to the machining of the different Individual parts costly to manufacture and because of the separate arrangement of the Axial channel in the recirculating ball nut is comparatively voluminous.

Finally, from DE-PS 21 49 392 a ball screw with Recirculating ball nut of the type mentioned is known, in which the ball return member Is cylindrical and centrally between two adjacent ball flights, for example is seated in a radial bore of the recirculating ball nut with an adhesive. To the ball return link to different spindle diameters, spindle pitches and ball sizes to be able to adapt and a continuous trouble-free ball circulation to enable the load bearing line in the nut thread in the transition area of the balls in the ball return member through a point of discontinuity in the form of a Bevel interrupted. The ball return channel has a rectangular cross section and runs angled in a straight line on the underside of the feedback member. Because of the cylindrical shape and the tight fit, it is difficult to determine the exact radial position of the feedback link in the recirculating ball nut and secure for the long term. In addition, there is the possibility that the cylindrical return member by the forces exerted by the balls in operation in the wall opening around his The central axis is twisted, which ensures that the balls enter and leave the ball evenly Return channel obstructed. However, this also results in this design the known problems with other ball screws, that due to the relatively abrupt three-dimensional change in direction of the balls passing through the return channels as well as the corresponding pressure of the balls on the channel walls in the inlet and outlet area of the return gears impact stresses occur which occur after longer operating times can lead to permanent deformation of the overflow areas. Due to an inaccurate or the depth arrangement of the respective one changes after longer periods of operation Feedback links increase these problems.

The object of the invention is to provide a ball screw of the specified To create a class that is structurally simple and has a long service life away a smooth and uniform return of the balls from a roller table to the allows others and in which the radial depth arrangement of the ball return member can be easily adjusted.

According to the invention, this object is achieved by the characterizing features of claim solved The inventively designed ball return member leaves radially outwards into the correspondingly shaped recess of the recirculating ball nut use it without difficulty. It has a smaller height than the wall thickness the recirculating ball nut, so that there is still a sufficiently thick wall part to screw in the adjusting screw is available.

This allows the radial infeed of the ball return member by turning the screw can be sensitively adapted to the respective height of the roller tables.

The ball return member expediently has an elongated shape a flat surface and a profiled lower surface, in which a three-dimensional S-shaped groove is formed of partially cylindrical cross-section, which the Forms ball return channel. To engage the set screw on the side walls Allowing the elongated opening in the recirculating ball nut is the diameter the adjusting screw larger than the width of the ball return member, the radial Opening in the recirculating ball nut has a widened cylindrical central part, in the side walls of which thread segments are cut.