Gearbox

Abstract

Gearbox (10) with at least one sleeve (14) engaging with a push rod (16), a wheel (12) arranged on the sleeve (14), wherein the push rod (16), the sleeve (14) and the wheel (12) are positioned concentrically on an axis (100), and wherein the sleeve (14) has a sleeve shell (142) with at least one shell groove (144) arranged parallel and spaced from the axis (100), and the wheel (12) has a wheel hub (122) with at least one hub groove (124) arranged parallel and spaced from the axis (100) and opposite the shell groove (144), and the sleeve (14) and the wheel (12) are fixedly connected to one another in such a way that a pin (18) is arranged between the at least one shell groove (144) and the at least one hub groove (124), whereby a positive connection in the radial direction to the axis (100) between the sleeve (14) and the wheel (12), characterized in thatthat the pin (18) is a dowel pin and that the positive connection is established exclusively by the at least one pin (18), that a frictional connection and / or positive connection between the sleeve (14) and the wheel (12) is established by means of the pin (18), wherein the gear comprises a plurality of pins (18) and the sleeve shell (142) has a plurality of shell grooves (144) arranged parallel, spaced apart and symmetrically to the axis (100), and the wheel hub (122) has a plurality of hub grooves (124) arranged parallel, spaced apart and symmetrically to the axis (100) and opposite the shell grooves (144), wherein one of the pins (18) is arranged between one of the shell grooves (144) and one of the hub grooves (124), and that the wheel (12) is made of plastic and the sleeve (14) is made of metal.

Description

The invention relates to a transmission for converting a rotational movement into a translatory movement, which is preferably integrated in a steering system in a motor vehicle.Transmissions integrated in steering systems are known. Thus, DE 10 2008 014 402 A1 discloses an electromechanical steering system in which a drive torque of an electric motor is brought into effect in order to assist a driver of a motor vehicle during steering. For this purpose, the electromechanical steering system from DE 10 2008 014 402 A1 comprises a toothed rack, an electric motor and a transmission for converting a torque of the electric motor into an axial force on the toothed rack. For this purpose, the transmission has a belt drive with a first belt wheel, a second belt wheel and a belt coupling the belt wheels. The first belt wheel is seated on an output shaft of the electric motor. The second belt wheel is flanged onto a ball screw nut which is in engagement with the toothed rack and forms a ball screw drive with the latter.DE 699 12 236 T2 discloses a connecting element with a threaded spindle drive and its use in a robot arm. A positive and non-positive connection between a belt disk and a shaft is effected by a wedge.NIEMANN, G., Winter, H., & Hohn, B. (2001). Machine elements: Vol 1: Construction and calculation of connections, bearings, shafts (3rd edition ed.). Berlin, Heidelberg: Springer discloses machine elements for connecting shafts and hubs. A clamping pin can be used as a connecting element, for example.On the basis of this, the object of the present invention is to improve a transmission of the type mentioned at the beginning with regard to the fastening of the belt pulleys.This object is achieved with a transmission having the features mentioned in claim 1. There is also provided a steering system including this transmission according to claim 4 and a motor vehicle including this steering system according to claim 5.The transmission according to the invention comprises at least one sleeve engaging a push rod, a wheel arranged on the sleeve and at least one pin. The push rod and the sleeve and the wheel are positioned concentrically on an axis. The sleeve has a sleeve jacket with at least one jacket groove arranged parallel and spaced apart from the axis, and the wheel has a wheel hub with at least one hub groove arranged parallel and spaced apart longitudinally to the axis and opposite the at least one jacket groove. The sleeve and the wheel are connected to one another in a fixed manner in such a way that the at least one pin is arranged in each case between the at least one lateral groove and the at least one hub groove, as a result of which a positive fit is produced between the sleeve and the wheel in the radial direction about the axis.By rotating the wheel, the sleeve connected to the wheel also performs a rotational movement. The sleeve is in engagement with the push rod and sets it in a translatory movement. According to the invention, the sleeve is a nut, threaded nut or preferably a ball screw nut or ball nut. The push rod is correspondingly designed as a rack, spindle or preferably threaded spindle or the like corresponding to the sleeve.With the transmission according to the invention, other connections, which are more complex to implement, such as, for example, screws or adhesive bonding, can be dispensed with advantageously by the positive connection between the wheel and the sleeve which is present in the radial direction. When selecting the individual parts of the gear, a wide variety of pairings of materials are thus advantageously possible, since the suitability for adhesive bonding or screwing of the material is not relevant.Along with this, the present invention provides improved assembly capability of the individual parts of the transmission, since additional connecting means are not required. Assembly and also disassembly can thus be carried out more easily, quickly and non-destructively compared to conventional configurations.According to the present invention, it is possible to use, as the wheel, a gear, a pulley, or the like. In a preferred embodiment, the wheel is a belt wheel, in particular a toothed belt wheel. Thus, the transmission according to the invention is preferably driven by means of a belt drive.This is distinguished by a quiet, quiet running, good shock-absorbing properties, ease of maintenance and low weight. The transmission according to the invention can thus advantageously be acoustically decoupled, easily and additionally easily maintained.The positive connection is produced exclusively by the at least one pin.Additional formations for further fastening elements or driver elements can thus be omitted. This advantageously influences the manufacturing cost of the wheel and the sleeve on the one hand and thus advantageously reduces a higher notch effect due to additional formations on the other hand. The grooves preferably have a round cross section in order to minimize the notch effect. This also advantageously enables the production of the wheel from brittle materials.By means of the at least one pin, a frictional connection and / or a positive connection is produced between the sleeve and the wheel along the axis.This advantageously makes it possible to absorb axial forces without additional fastening elements. The number of different parts is thus reduced in a favorable manner.In addition, this advantageously allows a force introduction on the wheel, which also has an axial force component. Thus, the wheel can have, for example, a helical toothing. The helical toothing advantageously increases the load introduction surface on the wheel.As pins, standardized molded parts are preferably used. Thus, according to the invention, clamping pins or clamping sleeves can be used.This advantageously simultaneously produces a prestress between the wheel and the sleeve. A clearance between the sleeve and the wheel, which would have to be overcome first during a movement of the parts, is thus avoided. Thus, the movement of the wheel is advantageously followed by a direct reaction of the push rod.According to the invention, it is furthermore provided that the gear mechanism comprises a plurality of clamping pins and the sleeve casing has a plurality of casing grooves arranged along and symmetrically with respect to the axis and the wheel hub has a plurality of hub grooves arranged along and symmetrically with respect to the axis and opposite the casing grooves, in each case one of the pins being arranged between one of the casing grooves and one of the hub grooves.This advantageously provides improved runout properties of the wheel. Due to the grooves and pins arranged symmetrically to the axis, the masses of these fastening means are evenly distributed, so that imbalance is avoided.According to the invention, it is further provided that the wheel is made of plastic and the sleeve is made of metal.The use of plastic makes it possible to design the wheel with complex geometries at relatively favorable costs. In addition, the wheel made of plastic has a relatively small mass, which can be accelerated with less effort. In addition, a plastic wheel promotes the acoustic decoupling of the transmission by the good damping properties.In a further preferred embodiment of the invention, it is provided that the plastic is a thermosetting plastic.Thermosetting plastic is very temperature- and shape-resistant and, in addition, very chemical-resistant. With the use of thermosetting plastic as material for the wheel, the transmission according to the invention is thus advantageously suitable for use in the environment of an internal combustion engine of a motor vehicle.The transmission according to the invention is preferably integrated in a steering system in all of the configurations mentioned. This steering system is preferably arranged in a motor vehicle, wherein wheels of the motor vehicle can be deflected by means of the push rod of the transmission.The aforementioned advantages of the transmission according to the invention as a module thus benefit the steering system or the motor vehicle with the transmission as a component.Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.The invention is explained below in exemplary embodiments with reference to the associated drawings. The following are shown: FIG. 1 : a transmission according to the invention; FIG. 2 shows a wheel of the transmission according to the invention, and FIG. 3 : a sleeve of the transmission according to the invention.FIG. 1 depicts, by way of example and not limitation, a transmission 10 according to the invention. A push rod 16 is arranged along an axis 100. The axis 100 describes the central axis of the push rod 16. A sleeve 14 is arranged on the push rod 16, which is in engagement or operatively connected to the push rod 16 in such a way that the push rod 16 can be displaced into a translatory movement by a rotational movement of the sleeve 14.The push rod 16 and the sleeve 14 have force transmission elements corresponding to one another for this purpose. Thus, the push rod 16 is designed, for example, as a toothed rack, threaded spindle, ball screw or the like. The sleeve 14 is configured as a nut, a ball screw nut, and a ball screw nut, respectively, or the like. Depending on the embodiment, the tooth arrangements of the sleeve 14 and the push rod 16 engage directly in one another or the sleeve 14 and the push rod 16 are operatively connected to one another by means of balls of the ball circulation.The sleeve 14 is rotatably mounted in a bearing 20. The bearing 20 holds the sleeve 14 stationary in a plane orthogonal to the axis 100. Rotation of the sleeve 14 causes a translatory displacement of the push rod 16 along the axis 100. In this case, the rotation of the sleeve 14 in one direction of rotation causes a displacement of the push rod 16 to one side and the rotation of the sleeve 14 in the opposite direction of rotation causes a displacement of the push rod 16 to the other side.On at least a part of the circumferential surface of the sleeve 14, a wheel 12 is arranged. The sleeve 14 and the wheel 12 and the push rod 16 are arranged concentrically with one another and together have the axis 100 as the center line.The wheel 12 and the sleeve 14 are connected to one another in a form-fitting manner in the circumferential direction. Thus, torques may be transmitted between the wheel 12 and the sleeve 14. The form-fitting connection is produced with pins 18. In FIG. 1, the number thereof is four. The pins 18 are arranged along the axis 100, i.e. the longitudinal axes of the pins 18 run substantially parallel to and spaced apart from the axis 100. The pins 18 have a symmetrical arrangement. Thus, the pins in FIG. 1 are positioned mirror-symmetrically to the axis 100. According to the invention, an arrangement with pins 18 spaced apart from one another at the same angle is also possible. The number of pins 18 depends on the design of the transmission 10.In the longitudinal direction to the axle 100, according to the invention, a frictional connection between the sleeve 14 and the wheel 12 is additionally preferably produced by the pins 18.As pins 18 substantially elongated shaped elements such as plug pins or spring pins are used. Preferably, at least one of the pins is a clamping pin or a clamping sleeve. According to the invention, the clamping pin can also be designed as a connex pin or spiral pin. With the use of clamping pins, a permanent prestress is simultaneously realized between the wheel 12 and the sleeve.As shown, the pins 18 are preferably the sole force transmitting elements between the wheel 12 and the sleeve 14. However, it is also possible for the wheel 12 and the sleeve 14 to additionally be provided with formations which, together with the pins 18, produce a positive fit in the radial direction between the wheel 12 and the sleeve 14.It is furthermore possible for further components to generate a force fit and / or form fit between the wheel 12 and the sleeve 14 along the axis 100.To receive the pins 18, the wheel 12 and the sleeve 14 are provided with corresponding grooves. Thus, FIG. 2 shows, by way of example and not limitation, individually the wheel 12 of the transmission 10.The wheel 12 shown has a recess in the center for receiving the sleeve 14. The recess is substantially circularly symmetrical about the axis 100. The inner circumferential surface around the recess is formed by a wheel hub 122.On the wheel hub 122, the wheel 12 has hub grooves 124. The hub grooves 124 are formed along the axis 100. The hub grooves 124 are also arranged symmetrically to the axis 100, so that no imbalance is generated in the wheel 12 by the hub grooves 124.At its outer periphery, the wheel 12 has straight teeth engageable with teeth of a belt. A drive of the wheel 12 can thus be generated, for example, via a belt drive. The wheel 12 shown is a toothed belt wheel made of plastic. According to the invention, the wheel 12 can also be formed as a gearwheel or another substantially disk-shaped machine element. In this case, other types of toothing, such as helical toothing, and other materials are provided, for example metallic materials.In FIG. 3, the sleeve 14 of the transmission 10 is depicted individually by way of example and not by way of limitation. The sleeve 14 has a substantially cylindrical recess along the axis 100 for receiving the push rod 16. In addition, a bearing region 146 is formed for arranging the sleeve 14 in the bearing 20. On the outer circumferential surface, the sleeve jacket 142, jacket grooves 144 are recessed.The jacket grooves 144 together with the hub grooves 124 form the locations for the placement of the pins 18, wherein in the mounted transmission 10 a respective hub groove 124 is arranged opposite a jacket groove 144. According to the invention, the pins 18 are preferably seated with an interference fit between the grooves.List of reference characters10 Transmission 12 Wheel 122 Wheel hub 124 Hub grooves 14 Sleeve 142 Sleeve jacket 144 Jacket grooves 146 Bearing region 16 Push rod 18 Pins 20 Bearing 100 Axle

Claims

Transmission (10) having at least one sleeve (14) which engages with a push rod (16), a wheel (12) which is arranged on the sleeve (14), wherein the push rod (16) and the sleeve (14) and the wheel (12) are positioned concentrically on an axle (100), and wherein the sleeve (14) has a sleeve casing (142) having at least one casing groove (144) which is arranged parallel and at a distance from the axle (100), and the wheel (12) has a wheel hub (122) having at least one hub groove (124) which is arranged parallel and at a distance from the axle (100) and opposite the casing groove (144), and the sleeve (14) and the wheel (12) are connected to one another in a fixed manner in such a way that a pin (18) is arranged in each case between the at least one casing groove (144) and the at least one hub groove (124), whereby a form fit is produced between the sleeve (14) and the wheel (12) in the radial direction to the axis (100), characterized in that the pin (18) is a clamping pin and that the form fit is produced exclusively by the at least one pin (18), that a force fit and / or form fit is produced between the sleeve (14) and the wheel (12) by means of the pin (18), wherein the gear comprises a plurality of pins (18) and the sleeve jacket (142) has a plurality of jacket grooves (144) arranged parallel and spaced apart and symmetrical to the axis (100) and the wheel hub (122) has a plurality of hub grooves (124) arranged parallel and spaced apart and symmetrical to the axis (100) and symmetrically to the jacket grooves (144), each opposite one of the pins (18) being arranged between one of the jacket grooves (144) and one of the hub grooves (124), and in that the wheel (12) is made of plastic and the sleeve (14) is made of metal.Transmission according to Claim 1, characterized in that the plastic is a thermosetting plastic.Transmission according to Claim 1 or 2, characterized in that the wheel (12) is a belt wheel.Steering system having a transmission according to one of Claims 1 to 3.Motor vehicle having at least one steering system according to Claim 4, wherein wheels of the motor vehicle can be deflected by means of the push rod.

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