DE102017204026A1 - Method and device for producing toothed racks - Google Patents

Abstract

The invention relates to a method for the production of toothed racks (51, 61) which extend in the direction of a longitudinal axis (L) and in a plane parallel to the longitudinal axis (L) toothing a toothing (9) with transverse to the longitudinal axis (L) in one Tooth direction extending teeth (92), in which at least one rack blank (5, 6) is clamped in a clamping device (3) and a tool head (2) of a processing machine in the tooth direction in the tool engagement is moved parallel to the toothing plane, wherein by the tool head (2 ) At least one tooth is introduced parallel to the toothing plane. In order to enable a more efficient production of racks and a faster generation of the toothing (9), the invention proposes that at least two rack blanks (5, 6) are clamped parallel to each other in the clamping device (3) and the tool head (2) in each case over both rack blanks (5, 6) continuous working stroke with continuous tool engagement is moved parallel to the common toothing plane (7).

Description

State of the art

The invention relates to a method for the production of toothed racks, which extend in the direction of a longitudinal axis and in a plane lying parallel to the longitudinal axis toothing a toothing with transverse to the longitudinal axis in a tooth direction teeth, wherein at least one rack blank is clamped in a jig and a Tool head of a machine tool in the tooth direction in the tool engagement is moved parallel to the toothing plane, wherein at least one tooth is introduced parallel to the toothing plane by the tool head. An apparatus for carrying out the method is likewise an object of the invention.

In steering gears of motor vehicles such a rack is slidably mounted in the direction of its longitudinal axis and connected via tie rods with the stub axles of the steerable wheels. In the longitudinally extending toothing of the rack engages a steering shaft mounted on a steering pinion, so that rotation of the steering shaft is converted by a displacement of the rack connected to the steering knuckle in a steering angle of the wheels.

To produce a rack, a rack blank is provided, usually a rod-shaped section with a round, semicircular (D-shaped), Y-shaped or other cross-section, preferably of steel. In this rack blank, a plurality of teeth is introduced by subsequent processing, which are arranged parallel to each other and perpendicular or oblique to the longitudinal axis and together form the teeth arranged parallel to the toothing plane.

The shaping of the teeth in a rack blank can be done by machining, for example by milling. A milling machine for milling the teeth of a rack is made of DE 1 033 487 A known. This has as a tool head on a milling head which is movable relative to a clamping device. For example, the tensioning device is mounted on a cross slide which is horizontally adjustable in two directions. The method for processing provides that a milling cutter, for example a disk or roll milling cutter, is brought into cutting engagement with the rack blank clamped in the machining position in the clamping device and moved in a working stroke in the tooth direction parallel to the toothing plane across the rack blank, so that a corresponding Tooth or a tooth portion is cut transversely to the longitudinal axis. Subsequently, in each case the feed of the rack blank takes place in the direction of its longitudinal axis by at least one tooth width relative to the milling head until successively all the teeth are introduced over the length of the toothing.

In the known milling machine, a rack blank is clamped in the clamping device and the teeth are milled by means of repeated strokes of the tool head transversely to the longitudinal axis until the toothing is complete and the rack is processed. Subsequently, the clamping device is brought out of the machining position and the finished rack stretched out of the clamping device. Then a new rack blank is clamped and the tensioning device brought back into the machining position in front of the tool head, where the teeth are milled.

The disadvantage is that in the processing position by means of the tool head only one rack blank during molding of the teeth can be processed. This results in the known manufacturing process relatively much time for the workpiece change.

In view of the above-described problem, it is an object of the present invention to provide a more rational method for the production of racks, which allows a faster generation of the teeth, as well as an apparatus for performing the method.

Presentation of the invention

This object is achieved by a method having the features of claim 1 and a device having the features of claim 8. Advantageous developments emerge from the subclaims.

To carry out the method according to the invention, it is proposed that at least two toothed rack blanks be clamped parallel to one another in the tensioning device and the tool head is moved parallel to the common toothing plane in each case in a working stroke passing through both toothed rack blanks.

While only a single rack blank is held in the processing position in the prior art, at least two rack blanks are clamped with their longitudinal axes next to each other, parallel to each other in the clamping device according to the invention. The toothed rack blanks clamped in this way have a common, continuous toothing plane, which can be machined by means of a tool head is accessible. The tool head is moved in a working stroke in the tool engagement parallel to the toothing plane transverse to the longitudinal axis relative to the adjacent clamped rack blanks, and the tool is guided parallel to the toothing plane through the initially unprocessed surface of the rack blank, wherein on the Zahnstangerohlinge each at least one transversely continuous tooth or a tooth portion is generated. In other words, through both rack blanks continuous teeth are generated in one operation. As a result, all inventively clamped rack blanks can be processed substantially simultaneously in a working stroke transverse to the longitudinal axis, for example of a milling head by milling a continuous tooth structure with one or more teeth transversely in the clamped rack blanks. In this way, the formation of the teeth takes place practically simultaneously on both rack blanks, wherein the processing time through the tool head is comparable to the processing of a single blank in the prior art. After processing both or more rack blanks, the racks are stretched out with the finished teeth from the jig.

It may be advantageous that two rack blanks are clamped in pairs against each other in contact. For this purpose, two rack blanks are introduced into a corresponding receptacle of the clamping device and clamped together between clamping elements, for example, against each other can be pressed jaws. The rack blanks lie in direct contact in the longitudinal direction parallel to each other. The common toothing plane, which is structured as described according to the invention in each case in a continuous working stroke of the tool head with a continuous tooth or tooth portion, can extend over the toothed rack blanks transversely to the longitudinal axis without a gap, whereby burr formation can be reduced. The pairwise handling of the rack blanks and the finished racks can be particularly labor efficient.

Both the clamping, as well as the machining and the clamping of two or more rack blanks or racks, especially in the pairwise handling and processing, requires no much higher time and processing effort than in the prior art, in which only one rack made becomes. This results in a more rational and especially faster production of racks.

The indentation according to the invention over two or more racks transversely through teeth can be done by machining, such as milling, broaching, planing, bumping, grinding or the like, or by means of plastic forming processes such as rolling, pressing, kneading or the like. The tool head is equipped by means of appropriate tools for carrying out each of the procedures used. Accordingly, the tool head can have a tool for machining, for example a milling cutter or the like.

In a further development of the method according to the invention, it may be advantageous for the rack blanks to be clamped with substantially horizontal longitudinal axes with respect to a substantially vertical direction of gravity, the toothing plane being substantially perpendicular. The toothing plane extends in the vertical direction, preferably at an angle of ± 30 ° to the direction of gravity, wherein the individual, for example in pairs juxtaposed rack blanks are arranged horizontally, parallel to a horizontal direction, preferably at an angle of ± 30 ° to the direction perpendicular to the direction of gravity extending horizontal. Accordingly, the tooth direction is also substantially perpendicular, or inclined at a helical toothing against the vertical. For machining, the tool head is moved in working strokes parallel to the toothing plane in the vertical direction, ie up or down. It is advantageous that during machining machining chips and processed cooling and cutting fluid under the influence of gravity fall automatically from the processing area and can be easily removed.

It is furthermore conceivable and possible for the toothed rack blanks to be clamped vertically in pairs next to one another, so that they are arranged parallel to the direction of the gravitational force.

The rack blanks can be clamped against each other in the clamping device between clamping jaws. The clamping jaws are preferably arranged in pairs in the vertical direction, so that the rack blanks can be clamped horizontally in between. For clamping the clamping jaws are movable in the vertical direction against each other. Two or more pairs of jaws may be spaced apart longitudinally to securely fix the racks over their length.

For a rational production flow can be provided that first rack blanks clamped in a first clamping device in a loading position outside of the tool engagement while second rack blanks are in tool engagement in a second chuck in machining position for machining and rack racks finished from rack blanks are unloaded from a third chuck to the unloading position outside the tool engagement of the chuck, the chucks circumferentially or alternately in loading position, machining position and unloading position be positioned. The at least three tensioning devices can be brought by means of appropriate transport and positioning in time, which is determined by the duration of machining to produce the teeth in the machining position in tool engagement in front of the tool head, for loading or clamping the rack blanks in a loading position, and Unloading or unclamping the toothed finished racks to an unloading position. The loading and unloading position can be arranged in a flow of production in the flow direction in front of and behind the processing position. In this case, the clamping devices may be configured the same, for example, as along a production line along moving carriage, or on a revolver or carousel-like changing device, so that the or each of the clamping devices relative to the tool head is linearly movable and / or rotatable about an axis of rotation. The clamping devices can be alternately or cyclically positioned for machining in front of the tool head in time, so that a quasi-continuous, clocked production can be realized.

A device for producing toothed racks, which extend in the direction of a longitudinal axis and in a plane lying parallel to the longitudinal axis toothing have teeth with transverse to the longitudinal axis in a tooth direction teeth comprising a tool head and a clamping device in which a rack blank can be clamped, wherein a tool head in the tooth direction parallel to the toothing plane is movable for introducing at least one tooth parallel to the toothing plane, provides according to the invention that at least two rack blanks are clamped parallel to each other in the clamping device and the tool head in a continuous over both rack blanks working stroke parallel to a common toothing plane with through Tool engagement is movable.

The device is configured, for example, as a machine for machining with a tool head, for example as a milling machine or as a milling tool with a milling head, wherein the tool head for introducing teeth or tooth sections as for the previous method is movable transversely to the longitudinal direction parallel to the toothing plane, wherein the machining direction the tooth direction corresponds. In a working stroke of the tool at least in two nebeneinader adjacent clamped rack blanks continuously formed a tooth or consisting of several teeth tooth portion, for example milled. As a result, the process according to the invention can be implemented efficiently.

An advantageous embodiment provides that the toothing plane is arranged substantially perpendicularly parallel to a direction of gravity, and the longitudinal axes are aligned substantially horizontally. In particular, in a machining process, it is advantageous if the toothing plane is in a range of about ± 30 ° to the vertical, so that chips and cooling and lubricating fluid flow by gravity down automatically. For this purpose, it is also advantageous if the teeth of the toothing are also substantially perpendicular, which can be achieved in that the longitudinal axes of the racks are in a range of about ± 30 ° to the horizontal. By inventively across two or more racks across grooves between teeth teeth chips and liquids occurring during processing can drain well and easily down.

In an advantageous embodiment, it is provided that a plurality of clamping devices is provided, which are each positioned relative to the tool head either in the machining position or in loading or unloading position. The clamping devices can be positioned by means of a motorized, preferably automated transport or positioning device as described above alternately or cyclically circumferentially in the power stroke for processing in front of the tool head, and simultaneously in loading and unloading position for loading rack racks and for removal of finished racks.

As described above for the method, the device can be designed to be able to carry out advantageous developments of the method, for example with clamping devices for clamping with a substantially vertical toothing plane.

list of figures

• 1 eine Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens in einer schematischen Ansicht von oben,
• 2 eine Spannvorrichtung der Vorrichtung gemäß 1 in einer schematischen perspektivischen Ansicht,
• 3 eine Spannvorrichtung mit eingespannten Zahnstangenrohlingen in einer schematischen Seitenansicht in Bearbeitungsposition,
• 4 zwei gebaute Zahnstangen,
• 5 eine Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens in einer zweiten Ausführungsform in einer schematischen Ansicht von oben ähnlich wie in 1,
• 6 eine Vorrichtung mir einer Spannvorrichtung in einer zweiten Ausführungsform in einer schematischen Ansicht in Längsrichtung.

Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In detail show:

• 1 a device for carrying out the method according to the invention in a schematic view from above,
• 2 a tensioning device of the device according to 1 in a schematic perspective view,
• 3 a clamping device with clamped rack blanks in a schematic side view in the machining position,
• 4 two built racks,
• 5 a device for carrying out the method according to the invention in a second embodiment in a schematic top view similar to in FIG 1 .
• 6 a device with a clamping device in a second embodiment in a schematic longitudinal view.

Embodiments of the invention

In the various figures, the same parts are always provided with the same reference numerals and are therefore usually named or mentioned only once in each case.

1 shows a device according to the invention 1 for carrying out the method according to the invention, which is described below by way of example as a milling machine, but can also be configured to carry out another machining or non-cutting machining method suitable for the formation of toothings.

The device 1 has one as a milling head 2 trained tool head having a milling tool, of which in a processing area 21 a workpiece processed, that can be milled.

Furthermore, the device comprises 1 several, in the example shown, three clamping devices 3, which are constructed the same, as in 2 shown in perspective.

Each of the tensioners 3 has two pairs of jaws 41 and 42 on that in a transverse direction Q , in the 1 pointing out of the plane of the drawing, are movable against each other, as in 2 indicated by the oppositely directed arrows.

The transverse direction Q with respect to in the representation of 2 downward pointing direction of gravity G vertically upwards.

Between the jaws 41 and 42 are each two rack blanks 5 and 6 clamped in pairs. They extend in a longitudinal direction L , which is arranged horizontally or horizontally perpendicular to the transverse direction, parallel in the transverse direction Q next to each other, lying with their inner sides facing each other 51 and 61 directly to each other. They are from the jaws 41 and 42 in the clamped state pressed against each other virtually gap-free.

The tensioning device 3 facing away, the milling head 2 facing side surfaces define a continuous, common toothing plane 7 , This gearing level 7 extends with respect to the direction of gravity G perpendicular to the transverse direction Q and to the longitudinal direction L ,

A pair of rack blanks 5 and 6 will be in an in 1 dashed marked loading area 81 in which there is a tensioning device 3 outside the editing area 21 in loading position, between the jaws 41 and 42 clamped. Subsequently, the clamping device 3 by means of a positioning drive, not shown, in the longitudinal direction in front of the milling head 2 in the editing area 21 positioned as well as in 1 dashed lines.

3 shows a look in the drawing of the 1 Seen from the left, perpendicular to one in the editing area 21 located clamping device 3 , frontally on the common gearing plane 7 , in front of which the milling head 2 in machining position. As can be seen, the milling head is used for machining 2 in the machining direction Z obliquely to the transverse direction Q across both rack blanks 5 and 6 moves, wherein by means of a not shown in detail, known milling tool in a working stroke a tooth portion 91 milled, one, or as shown some teeth 92 includes. The milling head 2 is schematically drawn in center position, with the already milled teeth 92 in the rack blank 6 are shown by solid lines, and in the same stroke still continuous in the adjacent clamped rack blank 5 teeth to be milled 92 indicated by dashed lines.

The whole gearing 9 is distributed over a defined length s and is made up of the totality of the teeth 92 formed in a plurality of tooth sections 91 in successive working strokes of the milling head 2 each in the rack blanks 5 and 6 are milled. In this way, the gearing becomes 9 one in the editing area 21 in front of the milling head 2 positioned clamping device 3 finished. The milled gearing can be a straight toothing, a helical gearing or a variable gearing.

After performing a predetermined number of work strokes, which is responsible for the molding of all teeth 92 are required, the rack blanks 5 and 6 to racks 51 and 61 processed. After completion of this processing, the clamping device 3 from the editing area 21 in a discharge area 82 transported, from which the finished racks 51 and 61 by loosening the clamping jaws 41 and 42 stretched out and out of the clamping device 3 can be removed.

4 shows two finished racks 51 . 61 with a round cross section, in which the teeth 9 over the defined length s of the racks 51 . 61 was introduced.

As in 1 shown, at least three of the clamping devices 3 circulating each time during a cycle in parallel in the loading area 81 with rack blanks 5 and 6 by the invention according to the invention in pairs clamping between the clamping jaws 41 and 42 be fitted in the editing area 21 can the rack blanks 5 and 6 for milling the teeth 92 the gearing 9 in front of the milling head 2 be positioned, and by also pairwise removing the then finished toothed racks 51 and 61 be discharged. In the next cycle, the clamping devices move 3 one more position, with one or the empty clamping device 3 from the unloading area 82 for re-equipping with rack blanks 5 . 6 in the loading area 81 can be transported.

Alternatively, as in 5 shown, several clamping devices 3 be attached to the sides of a turntable 31 which is rotated in time around an axis, so that in each case one arranged on the respective side clamping device 3 in the loading area 81 , in the editing area 21 or in the unloading area 82 located. The clamping devices 3 are thus cycled clocked through the various stations, as above for the device 1 out 1 explained in principle.

6 shows a possible variant of a clamping device 3 , This has two pairs of jaws 41 and 42 on, in the transverse direction Q , So with respect to the direction of gravity G are arranged one above the other. This allows two pairs of semicircular rack blanks simultaneously 5 and 6 be clamped and edited. It will be in both pairs in a working stroke of the milling head 2 , which is about all clamped rack blanks 5 and 6 is moved, across teeth 92 milled.

Due to the vertical arrangement of the gearing plane 7 the racks 5 and 6 For example, chips and cooling and lubricating liquids generated by gravity during milling can be easily removed.

LIST OF REFERENCE NUMBERS

1

Device (milling machine)

2

milling head

21

editing area

3

jig

41.42

jaws

5.6

Rack blanks

51.61

racks

7

toothing plane

81

loading area

82

unloading

9

gearing

91

tooth portion

92

tooth

Q

transversely

L

longitudinal direction

G

The direction of gravity

Z

machining direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1033487 A [0004]

Claims (10)

Method for producing toothed racks (51, 61) which extend in the direction of a longitudinal axis (L) and toothing (9) in a tooth plane lying parallel to the longitudinal axis (L) with teeth extending transversely to the longitudinal axis (L) in a tooth direction ( 92), in which at least one rack blank (5, 6) in a clamping device (3) is clamped and a tool head (2) of a machine tool in the tooth direction in the tool engagement is moved parallel to the toothing plane, wherein by the tool head (2) at least one tooth is introduced parallel to the toothing plane, characterized in that at least two toothed rack blanks (5, 6) are clamped parallel to each other in the clamping device (3) and the tool head (2) in each case over both rack blanks (5, 6) continuous working stroke with continuous tool engagement is moved parallel to the common toothing plane (7). Method according to Claim 1 , characterized in that in each case two rack blanks (5, 6) are clamped in pairs against each other fitting. Method according to one of the preceding claims, characterized in that the rack blanks (5, 6) with respect to a substantially vertical direction of gravity (G) with substantially horizontal longitudinal axes (L) are clamped, wherein the toothing plane (7) is vertical. Method according to one of the preceding claims, characterized in that the toothed rack blanks (5, 6) in the clamping device (3) between clamping jaws (41, 42) are braced against each other. Method according to one of the preceding claims, characterized in that first rack blanks (5, 6) in a first tensioning device (3) are clamped in a loading position (81) outside the tool engagement, while second rack blanks (5, 6) are mounted in a second tensioning device ( 3) in the machining position (21) for machining in the tool engagement, and from rack blanks (5, 6) finished racks (51, 61) from a third clamping device (3) in unloading position (82) outside the tool engagement of the clamping device (3) be stretched, wherein the clamping devices (3) circumferentially or alternately in loading position (81), processing position (21) and unloading position (82) are positioned. Method according to one of the preceding claims, characterized in that the clamping device (3) relative to the tool head (2) is linearly movable and / or rotatable about an axis of rotation. Method according to one of the preceding claims, characterized in that the tool head (2) has a tool for machining, preferably a milling tool. Device for producing toothed racks (51, 61) which extend in the direction of a longitudinal axis (L) and in a toothing plane (7) lying parallel to the longitudinal axis (L) a toothing (9) with a direction transverse to the longitudinal axis (L) in a tooth direction extending teeth (92), comprising a tool head (2) and a clamping device (3) in which a rack blank (5, 6) can be clamped, wherein a tool head (2) in the tooth direction in the tool engagement parallel to the toothing plane (7) is movable for introducing at least one tooth (92) parallel to the toothing plane (7), characterized in that at least two toothed rack blanks (5, 6) can be clamped parallel to one another in the clamping device (3) and the tool head (2) can be clamped in one over both toothed rack blanks (5 , 6) continuous working stroke parallel to a common toothing plane (7) with continuous tool engagement is movable. Device after Claim 8 , characterized in that the toothing plane (7) is arranged substantially vertically parallel to a direction of gravity (G), and the longitudinal axes are aligned substantially horizontally. Device according to one of Claims 8 or 9 , characterized in that a plurality of clamping devices (3) is provided which are each relative to the tool head (2) selectively in the processing position (21) or in the loading or unloading position (81/82) can be positioned.

Images