Method for producing a channel in a shaft tube

A method for producing a spray channel on a shaft tube, whereby a completed shaft tube can output fluid from within the shaft tube to outside of the shaft tube, the method may include introducing at least one through-opening with a diameter D1≥1.5 mm into the shaft tube and arranging at least one additional element in or on the at least one through-opening such that the spray channel is at least partly formed by the at least one additional element.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Application No. DE 10 2020 209 633.3 filed on Jul. 30, 2020, the contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a method for producing a spray channel in a shaft tube. The invention additionally relates to a camshaft having a shaft tube produced according to such a method.

BACKGROUND

In the case of hollow shafts, for example shaft tubes of camshafts, which comprise a specific oil or coolant channel through an interior of the shaft tube, for example for lubricating cams and/or cam followers, through-openings with very small diameter of less than 1.5 mm are often demanded on the shaft tube. Making matters worse is that often these through-openings or bores cannot be introduced at a right angle to the shaft axis, since they are to supply coolant or oil to axially adjacent function elements, such as for example cams. However, through-openings in the shaft tube not running at a right angle to the shaft axis cannot be economically produced with conventional and cost-effective methods, such as for example drilling, punching or drill punching. In fact, such oblique through-openings can only be introduced through very cost-intensive or elaborate methods, such as for example electrochemical metalworking, eroding or laser drilling.

The present invention therefore deals with the problem of producing a shaft tube with at least one spray channel more cost effectively.

SUMMARY

The present invention is based on the general idea of no longer introducing a through-opening serving as spray channel with a diameter D1of less than 1.5 mm by means of very thin mechanical drills or elaborate methods, such as for example electrochemical metalworking, eroding or laser drilling, but initially producing such a through-opening larger and thus, in terms of production, simpler and more cost-effectively and subsequently provide the same with an additional element which forms at least one part of the spray channel later on. With the method according to the invention for producing a spray channel that is oriented in particular at least in parts obliquely to a shaft axis on a shaft tube, via which with completed shaft tube, fluid, for example coolant or oil, can be output from within the shaft tube to the outside, initially at least one through-opening with a diameter D1of ≥1.5 mm is introduced into the shaft tube. Introducing such a through-opening is comparatively easily possible even with conventional metal drills, so that the at least one through-opening can be easily and cost effectively produced technically. Following this, at least one additional element is arranged in the method according to the invention in or on the through-opening namely in such a manner that the spray channel is at least partly formed by the additional element. Through the entirely different procedure with the method according to the invention, in which the actual spray channel at least partly no longer runs in the actual shaft tube but in the additional element, the extremely elaborate and thus also expensive production of a spray channel by means of a very thin drilled through-opening directly in the shaft tube that was required to date can be omitted.

In an advantageous further development of the method according to the invention, a through-opening that is oriented obliquely to the shaft axis is initially introduced into the shaft tube, for example drilled in, with a diameter D1of more than 1.5 mm Following this, a sleeve is pressed into the through-opening, whose inner diameter D2is <1.5 mm and forms the actual spray channel Thus, the sleeve, which is comparatively easily producible and can likewise be easily cut to length according to a wall diameter of the shaft tube forms the actual spray channel in a shaft tube produced in such a manner.

Alternatively to this it is obviously also conceivable that initially a through-opening oriented orthogonally to the shaft axis is initially introduced into the shaft tube, which again has a diameter D1of more than 1.5 mm Following this, a cylindrical additional element is pressed into the through-opening which comprises a spray channel running obliquely or parallel to a cylinder axis with a diameter D3<1.5 mm Here, the spray channel in the additional element can likewise be comparatively easily produced by drilling.

In a further advantageous embodiment of the method according to the invention, at least two through-openings oriented orthogonally to the shaft axis having a diameter D1of ≥1.5 mm are initially introduced into the shaft tube. Such through-openings oriented orthogonally to the shaft axis each with a diameter D1of more than 1.5 mm can be comparatively easily produced even with conventional metal drills. Following this, an additional element designed as sphere ring having a number of interconnected spheres corresponding to the through-openings on the shaft tube is provided, wherein into each sphere a spray channel running obliquely or orthogonally to a sphere ring axis having a diameter DKof <1.5 mm will be introduced or is introduced. Following this, the sphere ring is mounted on the shaft tube in such a manner that each sphere at least partly engages in an associated through-opening and fluidically connects the respective spray channel in the sphere with the associated through-opening in the shaft tube. Here, the sphere ring substantially has the form of a chain of pearls, wherein the individual pearls represent the respective spheres. In contrast with a chain of pearls however no sphere with a thread onto which the individual spheres are threaded runs through the individual spheres, but in the sphere ring according to the invention the individual spheres are connected with ring segments arranged in-between, each of which terminate on a sphere surface. Such a sphere ring has at least two spheres, wherein obviously, when introducing four or more through-openings on the shaft tube, four or more spheres can also be provided on the sphere ring. Here, the sphere ring is mounted over the outer diameter of the shaft tube, wherein the individual spheres have a larger outer diameter than the diameter D1of the respective through-opening and because of this are held in the through-openings. Some spheres can comprise spray channels that are oriented obliquely to the sphere ring axis and some spheres spray channels that are oriented orthogonally to the sphere ring axis, wherein it is also conceivable that spray channels are oriented obliquely or orthogonally to the sphere ring axis.

In a further preferred embodiment of the method according to the invention, at least two through-openings oriented orthogonally to the shaft axis each with a diameter D1of ≥1.5 mm are practically introduced into the shaft tube. An additional element designed as an outer ring having a number of spray channels preferentially corresponding to the through-openings on the shaft tube running obliquely or orthogonally to an outer ring axis each with a diameter DAR<1.5 mm is provided. Following this, an additional element designed as outer ring having a number of spray channels running obliquely or orthogonally to an outer ring axis corresponding to the through-openings on the shaft tube each diameter DAR<1.5 mm is provided. The outer ring is now mounted or slid onto the shaft tube in such a manner that at least one spray channel sits on an associated through-opening and/or fluidically connects the same with the associated through-opening. Preferentially, the number of the spray channels in the outer ring corresponds to the number of through-openings in the shaft tube, wherein at the same time an arrangement of the through-openings and of the spray channels in the outer ring is matched to one another so that these can be arranged congruently to one another. In order to be able to achieve a simplified assembly and at the same time a flexible oil supply it can be provided that on an outer lateral surface of the shaft tube an annular groove that is open towards the outside and/or an annular groove on an inner lateral surface of the outer ring that is open towards the inside are/is arranged, wherein the annular groove in the outer lateral surface of the shaft tube connects the individual through-openings, while the annular groove in the inner lateral surface of the outer ring connects the individual spray channels with one another. By way of this it is possible to arrange the outer ring in almost any angle-of-rotation position via the through-openings and still fluidically couple the through-openings with the spray channels.

In a further advantageous embodiment of the method according to the invention, at least two through-openings arranged orthogonally to the shaft axis each with a diameter D1≥1.5 mm are initially introduced into the shaft tube. Following this, an additional element designed as an inner ring with a number of spray channels running obliquely or orthogonally to an inner ring axis preferentially corresponding to the through-openings on the shaft tube each with a diameter DIR<1.5 mm is provided. The inner ring is now slid into the shaft tube in such a manner that at least one spray channel is communicatingly connected fluidically with at least one through-opening. In order to be able to likewise achieve an angle independent assembly of the additional element designed as inner ring, a circumferential ring groove can be provided on an outer lateral surface of the inner ring and/or on an inner lateral surface of the shaft tube in the region of the spray channels or of the through-opening, which makes possible transporting oil or coolant from a spray channel either directly through an associated through-opening or indirectly via the ring groove to an adjacent through-opening.

In a further particularly advantageous embodiment of the method according to the invention, at least one through-opening oriented orthogonally to the shaft axis is again introduced into the shaft tube. Preferentially, at least two through-openings oriented orthogonally to the shaft axis are introduced into the shaft tube in order to be able to avoid an unbalance of the shaft tube. Following this, an additional element designed as ring with a front face running obliquely to a ring axis is provided, wherein the front face in the mounted state forms a part of the spray channel. The ring is now mounted onto the shaft tube in such a manner that the oblique front face sits over the at least one through-opening so that the part of the spray channel formed by the front face is fluidically connected with the associated through-opening and makes possible spraying out of liquid, for example coolant or oil obliquely to the shaft axis of the shaft tube. By way of this, a particularly cost effective production of a shaft tube with spray channels running obliquely to the shaft axis is possible.

Further, the present invention is based on the general idea of forming a camshaft with a shaft tube, wherein the shaft tube is produced according to the method in accordance with one of the preceding paragraphs and wherein on the shaft tube a cam is arranged at the same time, which is oriented or arranged relative to the at least one spray channel in such a manner that during the operation it is supplied with oil via the spray channel. By way of this, for example a camshaft with spray channels oriented obliquely to the shaft axis can be technically produced easily and cost effectively.

Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the associated figure description by way of the drawings.

It is to be understood that the features mentioned above and still to be explained in the following can not only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein same reference numbers relate to same or similar or functionally same components.

DETAILED DESCRIPTION

According toFIGS.2to6, a shaft tube1according to the invention, for example for a camshaft2, comprises multiple spray channels4which are at least in parts oriented obliquely to a respective shaft axis3, via which with mounted shaft tube1, for example with a camshaft2mounted in an internal combustion engine, fluid5, for example oil or coolant, can be output from within the shaft tube1to the outside. By way of the oblique arrangement of the respective spray channels4axially adjacent cam6can be supplied for example with fluid and thus lubricatable or coolable. A connection of the cam6with a cam follower that is not shown can also be cooled or lubricated via the fluid jet5. Obviously, these spray channels4can be oriented orthogonally to the shaft axis3.

InFIG.1, a shaft tube1′ known from the prior art is shown, in the case of which the respective spray channels4′ with a diameter of D1of less than 1.5 mm were introduced as through-openings7′ in a jacket tube of the shaft tube1′. Introducing such small through-openings7′, which additionally run in particular obliquely, i.e. at an angle α of less than 90° to the shaft axis3′, can only take place with extremely elaborate methods, for example electrochemical metalworking, eroding or laser drilling, as a result of which the production of the through-openings7′ and thus also of the spray channels4′ and altogether of the shaft tube1′ or of the camshaft2′ is comparatively elaborate and thus expensive. Even the introduction of through-openings7′ with a diameter of D1of less than 1.5 mm at a right angle to the shaft axis3′ is difficult.

For this reason, the method according to the invention for producing spray channels4on a shaft tube1was developed which, compared with the previous production method, is a simple and cost effective design. With the method according to the invention, at least one through-opening7with a diameter D1≥1.5 mm is initially introduced into the shaft tube1. Through the comparatively large diameter D1, conventional metal drills can also be employed without problem and because of this the respective through-openings7produced cost-effectively and simple technically. In the shaft tubes1shown according toFIGS.2to6, four through-openings7each are introduced. Following this, at least one additional element8is arranged in or on the through-opening7in such a manner that the spray channel4is formed by the additional element8at least in parts.

The additional element8can also be arranged in or on the through-opening7so that the spray channel4is at least partly oriented obliquely or orthogonally to the shaft axis3and because of this a fluid jet5emitted from the spray channel4includes an angle α<90° with the shaft axis3.

The spray channel4can be partly arranged or run in the through-opening7or in or on the additional element8.

Here, only the individually possible embodiments ofFIGS.2to6are described in more detail.

Looking atFIG.2it is noticeable that in the detail representation B there through-openings7oriented obliquely to the shaft axis3have been introduced, for example drilled into the shaft tube1. Following this, a sleeve9is introduced into the respective through-opening7with a diameter D1of ≥1.5 mm, wherein the inner diameter D2of the sleeve9is less than 1.5 mm, for example less than 1.0 mm and forms the actual spray channel4. Alternatively to this it is also conceivable that a through-opening7oriented orthogonally to the shaft axis3is introduced into the shaft tube1, as is shown in the detail representation A ofFIG.2. A cylindrical additional element8is now pressed into the respective through-opening7, which has a spray channel4running in particular obliquely or parallel to a cylinder axis10with a diameter D3of less than 1.5 mm, for example less than 1.0 mm. The cylinder axis10runs orthogonally to the shaft axis3, while the spray channel4includes an angle α<90° with the shaft axis3.

Looking at the embodiment according toFIG.3it is noticeable that there at least two, preferentially four through-openings7oriented orthogonally to the shaft axis3again with a diameter D1≥1.5 mm are initially introduced into the shaft tube1, wherein subsequently an additional element8formed as sphere ring11with a number of spheres13connected to one another via ring segment sections12corresponding to the through-openings7on the shaft tube1is provided, wherein in each sphere13a spray channel4running obliquely or orthogonally to a sphere ring axis4with a diameter DK<1.5 mm will be introduced or is introduced. By way of this, an oblique or orthogonal emitting of a fluid jet5or of fluid5and thus a cooling or lubricating of a cam6arranged axially adjacent to through-opening7is also possible. The sphere ring11is mounted on the shaft tube1in such a manner that each sphere13engages or sits on an associated through-opening7and fluidically connects the respective spray channel with the associated through-opening7. There, some spray channels4can be oriented obliquely and some orthogonally to the sphere ring axis14or all spray channels4can be oriented obliquely or orthogonally to the sphere ring axis14.

Looking atFIG.4a shaft tube1with at least two, preferentially four through-openings7oriented orthogonally to the shaft axis3is noticeable there, which through-openings7where introduced into the shaft channel1for example by means of drilling and with have a diameter D1≥1.5 mm. In addition to this, an additional element8formed as outer ring15according toFIG.4with spray channels4running obliquely to an outer ring axis16each with a diameter DAR<1.5 mm for example less than 1.0 mm, is provided. Alternatively to this, an additional element8formed as outer ring15with spray channels4running orthogonally to an outer ring axis16each with a diameter DAR<1.5 mm for example less than 1.0 mm can also be provided. It is likewise conceivable that with an additional element8formed as outer ring15spray channels4running both obliquely and also orthogonally to an outer ring16each with a diameter DAR<1.5 mm, for example less than 1.0 mm, are also provided. This means that some spray channels4are designed obliquely and some orthogonally to the outer ring axis16.

The outer ring15is now mounted onto the shaft tube1in such a manner that at least one, preferentially each spray channel4sits on an associated through-opening7or is fluidically connected with such. Here, the number of the spray channels4arranged in the outer ring15can correspond to the number and orientation of the through-openings7introduced into the shaft tube1.

In order to make possible a mounting of the outer ring15on the shaft tube1that is independent of the angle of rotation it is also conceivable that on an outer lateral surface of the shaft tube1a ring groove17is arranged. Analogously to this, a corresponding ring groove can also be provided on an inner lateral surface of the outer ring15, via which fluid5, for example coolant or oil, is fed from a through-opening7via the ring groove17to a respective spray channel4.

Analogously toFIG.4, the shaft tube1is formed according toFIG.5, wherein here the additional element8is not formed as outer ring15, but as inner ring18. Here, too, at least two, preferentially four or more through-openings7oriented orthogonally to the shaft axis3are initially introduced into the shaft tube1, for example drilled in. Here, the through-openings7each have a diameter D1≥1.5 mm Following this, the additional element8formed as inner ring18is provided with a number preferentially corresponding to the through-openings7on the shaft tube1running obliquely/or obliquely to an inner ring axis19each with a diameter DIR<1.5 mm, is provided. Here, some spray channels4can be oriented obliquely and some orthogonally to the inner ring axis19or all spray channels4can be oriented obliquely or orthogonally to the inner ring axis19. The inner ring18is now slid into the shaft tube1in such a manner that at least one, preferentially each spray channel4from the inside lies against an associated through-opening7and/or fluidically connects the respective spray channel4with the associated through-opening7, so that so that the fluid jet5or the fluid5can leave the shaft tube1via the spray channel4and the through-opening7.

Finally viewing the embodiment ofFIG.6, a shaft tube1is noticeable there, in the case of which initially at least 1 through-opening7oriented orthogonally to the shaft axis3is introduced, for example drilled into the shaft tube1. These at least one, preferentially four through-openings7have a diameter of D1of ≥1.5 mm and because of this can be comparatively easily produced even by means of conventional metal drills. According to the invention, an additional element8designed as ring20having a front face22running obliquely to a ring axis21is now provided or created with the method, wherein the front face22in the mounted state forms a part of the spray channel. The ring20is now mounted or slid onto the shaft tube1in such a manner that the oblique front face22sits over the at least one associated through-opening7so that the part of the spray channel4formed by the front face22is fluidically connected with the associated through-opening7. Since the oblique front face22is formed the same everywhere, a mounting on the shaft tube1that is independent of the angle of rotation is possible with the ring20according to the invention. Producing such a ring20is cost-effectively possible comparatively easily, as is the mounting of the same on the shaft tube1.

With the additional element8designed as ring20it is likewise possible to emit fluid5, which is stored in the shaft tube1under pressure via the respective through-opening7and the oblique front face22at an angle α<90° to the shaft axis3to the outside and thus lubricate or cool for example axially adjacent cams6.

On the whole, a shaft tube1, for a camshaft2can be produced with the method according to the invention, which compared with conventional shaft tubes1regarding the through-openings7and spray channels4is not only more cost effective but can also be significantly more easily produced technically.