EP3595841A1

EP3595841A1 - Method and device for work-hardening a crankshaft

Info

Publication number: EP3595841A1
Application number: EP18729637.1A
Authority: EP
Inventors: Alfons Reeb; Jochen Schmidt; Konrad Grimm
Original assignee: Maschinenfabrik Alfing Kessler GmbH; Alfing Kessler Sondermaschinen GmbH
Current assignee: Maschinenfabrik Alfing Kessler GmbH; Alfing Kessler Sondermaschinen GmbH
Priority date: 2017-06-14
Filing date: 2018-06-04
Publication date: 2020-01-22
Also published as: CN110740836A; DE102017113088A1; KR20200019194A; US20200216924A1; RU2743084C1; KR102451924B1; CN110740836B; WO2018228841A1; JP6894013B2; JP2020530084A; US11344980B2

Abstract

The invention relates to a method for work-hardening a crankshaft (4) comprising connecting rod journals (5), main bearing journals (6) and crank webs (7), the connecting rod journals (5) and the main bearing journals (6) being provided with oil holes (31). According to the invention, at least one end (30) of one of the oil holes (31) and/or at least one cylindrical portion (38) of the oil holes (31) is/are work-hardened.

Description

Method and device for work hardening a crankshaft

The invention relates to a method for work hardening a crankshaft, which has connecting rod journal, main bearing journals and crank webs, according to the preamble of claim 1.

The invention also relates to a device for impact hardening a crankshaft according to the preamble of claim 21.

The invention also relates to a crankshaft.

Due to the steadily progressing development and increase in performance of internal combustion engines and to this strict emission requirements, today's engines are increasingly stressed in consequence. For this reason, the engine industry, among other things high demands on the high-load and important for the function of an internal combustion engine crankshaft in terms of strength. In terms of design, there is often the requirement that the crankshaft should be light and the space requirement should be low. For the design of the crankshaft, this means that an increase in the load capacity should not be achieved by increasing the cross section, ie via the moment of resistance of the crankshaft, but if possible via local compressive residual stress states. For this reason, modern crankshafts are manufactured using a variety of machining and heat treatment processes, so that the crankshafts can be exposed to increasingly higher engine power.

Examples of such processes are thermal treatments, such as induction hardening and case hardening, laser hardening or nitriding, as well as strain hardening processes such as deep rolling, shot peening or impact hardening. These are common and largely mature processes that are suitable for a variety of purposes.

With regard to examples of such methods, reference is made to the following publications: EP 1 479 480 A1, EP 0 788 419 B1, EP 1 612 290 A1, DE 10 2007 028 888 A1 and EP 1 034 314 B1.

In particular, the impact hardening is an advantageous method for increasing the fatigue strength, in particular the bending fatigue strength and torsional fatigue, of crankshafts. The increase in the fatigue strength is achieved in that impact forces are introduced into the claimed areas in cross-sectional transitions and changes in cross section by cold forming, preferably hammering, by means of special impact tools in the crankshaft. As an example of such a method, reference is made to DE 34 38 742 C2 and EP 1 716 260 B1.

In order to avoid disadvantageous introduction of shear stresses during local hammering, DE 34 38 742 C2 proposes no relative movement at the time of the pressure pulse action between the body emitting the pulse and the workpiece surface transversely to the direction of the pulse to be held. For this purpose, the feed during the introduction of compressive residual stresses by the striking tools should be done gradually.

As a further development of this method, it has been proposed in EP 1 716 260 B1 that the crankshaft is continuously rotated during machining, during which the rotational movement of the crankshaft during the application of the impact force of the impact tool to the crankshaft segment to be machined Impact tool is stopped on the crankshaft. The impact pressures are chosen so that the rotational movement of the crankshaft is forcibly stopped by the impact movement.

For this purpose, however, within the drive device complex components such. As gear, clutches and / or spring systems necessary to avoid that the drive device suffers damage by the "forced stops". Furthermore, the timing of the crankshaft and the introduction of compressive residual stresses must be synchronized process reliable. The required mechanical components to ensure a robust system are complex and expensive.

Although the crankshafts are usually subjected to the mentioned thermal treatments and / or work hardening processes, a further constructional aspect can nevertheless lead to difficulties, in particular with regard to the torsional fatigue strength of the crankshaft. In order to allow oil supply during operation of the crankshaft, the main journals and the connecting rod journals are each provided with oil holes. Such oil wells can adversely affect the robustness of the crankshaft. When setting oil holes, care must therefore be taken not to reduce the load capacity of the crankshaft beyond a permissible level. In particular, by the high demands on the torsional strength of the crankshaft, the designers are thus limited in the dimensioning, positioning and / or orientation of the oil holes.

The present invention has for its object to provide an improved method for work hardening and a device for impact hardening of a crankshaft, in particular for increasing the fatigue strength of the crankshaft.

This object is achieved for the method by the features listed in claim 1 and for the device by the features listed in claim 21.

Finally, the invention is also based on the object of providing an improved crankshaft, in particular with regard to its durability.

With respect to the crankshaft, the object is achieved by the features listed in claim 22.

The dependent claims and the features described below relate to advantageous embodiments and variants of the invention. In the method according to the invention for work hardening a crankshaft, which has connecting rod journals, main journals and crank webs, the connecting rod journals and the main journals having oil holes, it is provided that at least one oil well end of one of the oil wells and / or at least one cylindrical portion of one of the oil wells is work hardened ,

The connecting rod journal and the main journals are hereinafter referred to in part as "pin" for simplicity. The term pin can mean both the connecting rod journal and the main bearing journals, as well as only the connecting rod journal or only the main journals. Insofar as this is not explicitly stated otherwise, here all three variants are encompassed by the term pin.

The invention is particularly preferably suitable for increasing the fatigue strength of, for example, crankshafts having a length of 0.2 to 8 m or more and / or main and connecting rod journal diameters of 30 to 500 mm or more. However, the invention is very particularly suitable for increasing the fatigue strength of large crankshafts of 1.5 to 8 m in length or more and / or main and connecting rod journal diameters of 100 to 500 mm or more.

An oil well may be a portion of the oil well that extends into the oil well from a mouth of the oil well, or from the transition of the oil well into the tread of the associated connecting rod journal or main journal to a certain depth. The upper portion or the opening into the tread portion of the oil hole can thus be referred to as oil well. The oil well end may comprise at least the mouth or the transition to the tread of the pin. In principle, however, the oil well consignment, starting from the mouth of the oil well, can also be up to a depth of 50%, preferably to a depth of 25%, more preferably to a depth of 10%, for example to a depth of 5% or 2% into the oil hole.

In the context of the invention, the oil well end may also merely be a transition radius at the transition to the tread. It can also be a transition radius at the transition to the tread and an adjoining chamfer or a subsequent reduction in the oil drilling program. In addition, the oil well program can also be merely a chamfer or a reduction of the oil well; An optionally present transition radius at the transition to the tread can therefore also be assigned to the tread within the scope of the definition of the invention. Thus, the oil well end may also extend into the oil well from a chamfer or countersink to a certain depth.

A cylindrical portion of the oil hole may be any portion of the oil bore within the crankshaft. The length of the cylindrical portion in the oil hole may be arbitrary and may include the entire length of the oil hole. In particular, it may also be a section that does not belong to the oil well program. Within the scope of the invention According to the definition, the cylindrical section of the oil hole does not include a transition radius, a chamfer or a countersink.

In the context of the invention, it is therefore possible to cold-work different areas of an oil well independently or in any combination:

a transition radius at the transition to the tread of the pin; and or

a chamfer or reduction of the oil hole; and or

at least one cylindrical portion of the oil hole or an inner circumferential surface of the oil hole at any depth.

The inventors have recognized that strain hardening of at least one of the oil well endings or possibly a part or the entire oil well can increase the robustness of the crankshaft. The crankshaft can thereby possibly be better adapted to the engine operation. In particular, the torsional fatigue strength of the crankshaft can be improved in a cold work hardening according to the invention of at least one of the oil well shipments.

Furthermore, the inventors have recognized that also a work hardening of at least one cylindrical section within an oil bore can increase the robustness of the crankshaft. It may also be particularly advantageous only a cylindrical portion, for. B. cold work hardening an initial and / or center area of the oil well without solidifying any of the oil well endings, in particular without a transition radius or a chamfer / countersink the oil well.

Furthermore, in the design and construction of the crankshaft with respect to the course of the oil holes, the number of oil holes and / or the diameter of the oil holes with a inventive work hardening of the oil well endings and / or cylindrical portions of the oil well extended possibilities, since the torsional strength of the crankshaft is less affected by the oil wells than is usual in the prior art.

Insofar as reference is made in the context of the invention to an oil bore of a connecting rod journal, it can in principle also be an oil bore of a main journal, if this is not explicitly excluded - and vice versa. An oil well whose oil well end and / or cylindrical section is to be work-hardened can basically be present at any bearing point or running surface of the crankshaft, for example also in an input or output shaft of the crankshaft. The terms "connecting rod journal" or "main journal" can accordingly be reinterpreted by a person skilled in the art.

Depending on the type of crankshaft used, it can be provided that several, a majority or all connecting rod journal have oil bores. Accordingly, depending on the particular type of crankshaft, it may be provided that several, a majority or all main bearing journals have oil bores. It can also be provided that a journal (connecting rod journal or main journal) has one, two or more oil holes. For example, in crankshafts for V-type engines, two oil bores offset axially along the rotational axis of the crankshaft are usually provided in the connecting rod journal to preferably attach two connecting rods or connecting rods. In contrast, in a crankshaft for an in-line engine only one oil hole is usually provided in the connecting rod journal.

The oil holes can pass completely through the pins or penetrate them. Ie. it can be provided on both sides of a pin openings or mouths and thus oil wells (this is especially true for the main journals). However, the oil holes can also end within the pin and so z. B. introduced as blind holes (this is especially true for the connecting rod journal).

The method according to the invention or the device according to the invention can also be used or used in crankshafts which have been previously processed to increase their fatigue properties by other methods. For example, a crankshaft that has been hardened by induction hardening can be improved later by strain hardening of the oil well ends or cylindrical portions of the oil wells. Likewise, uncured (soft) as well as nitrided, nitrocarburized or laser hardened crankshafts can be improved by work hardening the oil well ends and / or the cylindrical sections of the oil wells.

Preferably, it can be provided that first the bearing points of the connecting rod journal and / or the main journal of the crankshaft are hardened by a known method, after which transition radii between connecting rod journal and crank webs and / or transition radii between main journal and the crank webs of the crankshaft are work hardened, preferably impact-hardened, and wherein one, several or all oil well endings of the oil wells and / or one, several or all cylindrical portions of the oil wells of the crankshaft are work hardened. The processing sequence during strain hardening, in particular during impact hardening, can be arbitrary; in particular, processing steps can also take place simultaneously.

In one development of the invention, it may be provided that the oil well end or the oil well endings and / or the cylindrical section (s) is / are impact-solidified.

In the following, the invention will be described essentially with reference to impact hardening of at least one oil drilling end. This is not to be understood as limiting. In particular, at least one cylindrical portion of the oil well may also be impact strengthened, in addition to or independent of the impact strength of the oil well end. In principle, it is also possible to provide other work-hardening methods for solidifying the oil well end and / or the cylindrical section, including cold rolling, shot peening and / or hammering. However, impact hardening in particular has proved to be an advantageous and industrially efficient work hardening method with regard to work hardening of oil well endings and / or cylindrical sections of oil wells.

In a further development can be provided that in the oil well program and / or in the cylindrical section see a striking force is introduced by means of a percussion head of a percussion tool.

By introducing a striking force, it can be understood that the striking head of a percussion tool or a so-called "striker" of a striking device strikes against the region of the crankshaft to be consolidated, in the present case an oil-boring end or an inner wall of the cylindrical section. The stroke is targeted to the desired beat position. In most cases, a percussion piston is used, which transmits a strong impulse or a force impulse (eg pneumatically, hydraulically and / or electrically generated) to the impact head.

Depending on the impact force, visible impact impressions of the impact head can occur at the respective impact positions. The depth of the impact impressions and the quality or the depth effect of the inherent compressive residual stress depend on the selected impact force. The tool and the process parameters are preferably exactly matched to the respective crankshaft and, if necessary, to the oil hole and / or bearing point or running surface into which the oil drilling end discharges. In particular, it can be provided that all oil well endings or cylindrical sections of the oil bores to be solidified are successively impact-hardened by means of a striking tool or by means of a beater. However, it can also be provided that at least two or more oil well endings and / or cylindrical sections of the oil wells are simultaneously impact-solidified, for which purpose several impact devices, several impact tools and / or several impact heads can be provided. By simultaneously processing multiple oil well shipments or cylindrical sections, the process speed can be increased.

In a development of the invention it can be provided that a plurality, preferably a majority, particularly preferably all oil well endings of the connecting rod journal and / or main journal are cold-worked, in particular impact-strengthened.

Furthermore, it can be provided that a plurality, preferably a majority, particularly preferably all cylindrical sections of the oil bores of the connecting rod journal and / or main bearing journal are work-hardened, in particular impact-hardened. The inventors have recognized that, in particular, a work hardening of oil drill endings or cylindrical sections of oil bores of eccentrically running spigots or heavily loaded spigots, ie in particular the connecting rod journal of the crankshaft, significantly increases the robustness of the crankshaft. Thus, it may be particularly preferred that all oil well endings and / or all cylindrical sections of oil wells of the connecting rod trunnions are work hardened. If necessary, cold-hardening of oil bores or of cylindrical sections of oil bores of the main bearing journals can also be dispensed with in order to increase the process speed of the process according to the invention. Preferably, the strain hardening is achieved by impact hardening.

In a further development of the invention, it can be provided that the oil well end has a transition radius at the transition to a running surface of the respective journal, the transition radius being work hardened, preferably impact-hardened. In particular, the work hardening of the mouth of the oil well, d. H. the forward portion of the oil well consignment, which merges into the tread of the respective journal, has been found to be particularly efficient if the robustness of the crankshaft is to be improved. As a rule, the transition has a radius, a so-called transition radius. However, it can also be provided any reduction in the area of the mouth of the oil well, for example, a Planein- reduction or a profile depression, such as a conical profile recess. The work hardening, preferably the impact hardening of the oil well end at the transition to the tread is advantageous regardless of the specific design of the transition of the respective pin.

It may also be provided a work hardening of an oil well, which merges without a reduction or a transition radius in the tread of the respective pin.

In a further development, it can also be provided that the oil drilling end has a chamfer, the chamfer being impact-hardened. Depending on the application, it may be provided, in particular, not to solidify a transition radius at the transition to the running surface, in order to avoid impact impressions in the area of the running surface brought about by impact hardening, as a result of which, if necessary, an improved running of the bearings can be ensured. A solidification can z. B. only starting with a chamfer or a reduction or even be provided starting with the cylindrical portion.

It can also be provided that the chamfer and at least part of the cylindrical section of the oil well are work-hardened, in particular impact-hardened, but not the transition radius. In a further development, it can also be provided during the impact hardening of one of the oil well endings to produce a transition radius of the oil well end or a countersinking or countersinking of the oil well end by the impact head. It can be provided simultaneously with the Schlagverfestigung an oil drilling a reduction or a transition radius of the oil hole ever to produce by the impact tool, the impact head and / or the impact force are chosen such that a corresponding imprint of the impact head at the mouth of the oil well , In a further development of the invention, it may further be provided that two oil well endings, which are offset axially in the same journal (along the axis of rotation of the crankshaft), are simultaneously impact-bonded by means of a striking tool having two impact heads.

For this purpose, it can be provided, in particular, that the force impact of the percussion piston is preferably distributed uniformly over the two impact heads via a deflection unit.

If more than two oil wells are to be provided in one journal of the crankshaft, the number of impactors of the impact tool can be correspondingly increased. Preferably, therefore, all Ölbohrungsendungen and / or cylindrical portions of oil holes of a pin are simultaneously impact-solidified.

Alternatively, it can also be provided that two or more oil bores formed in a journal are each impact-hardened individually, in particular by means of a striking tool which has only one impact head.

In a further development of the invention it can be provided that the impact tool is supported on at least one of the crank webs for alignment with one of the oil well endings and / or during impact hardening by at least one support element. In order to achieve the best possible result, the striking tool may preferably be aligned exactly with the oil hole end or mouth of the oil hole. Particularly preferably, the impact force can be introduced along the central axis of the oil hole.

A corresponding support element, which is preferably formed from an elastic material or has an elastic material, can support the exact alignment of the striking tool. The elastic material may be, for example, a plastic, in particular a soft plastic or a rubber material. The support member may also be formed of a non-elastic material, such as brass or other metal. The support element is preferably designed such that it surrounds the impact tool between the two crank webs, which surround a respective stud to be impact-hardened. The support member may preferably be arranged on the outside of the impact tool and dimensioned such that the impact tool between two crank arms is inserted and supported by them. The extension of the impact tool together with the support element can thus preferably correspond in the axial direction of the crankshaft to the distance (in the axial direction) between two crank webs which surround the journal having the impact-hardening oil bore. The support element may be formed in one piece or in several parts. In a preferred embodiment of the invention can be provided that the impact head for impact hardening has a spherical surface.

The impact head may preferably be substantially spherical in shape, in particular in the front region, or at the front end of the impact head, which strikes against the cure shaft for solidification. In principle, however, the impact head can have any desired geometry and can also be oval, hemispherical or flat, for example.

However, a spherical surface of the impact head has been found to be particularly suitable for impact hardening of the oil well endings or the cylindrical sections of the oil bores, since a centering or alignment of the impact tool can be simplified thereby.

In a development, it can be provided that the impact head has a mold section for impact hardening, the shape of which is adapted to the transition radius to be consolidated and / or to the chamfer or the course / design of the oil well end, in particular in the mouth region.

The mold section may in particular correspond to a negative mold of the transition radius of the oil well end. In principle, the percussion head for impact hardening may have a mold section whose shape is adapted to the section of the oil well end which merges into the running surface of the respective peg.

In a further development, it can also be provided that impact heads with different diameters are used for impact hardening of the oil well end, such that the impact heads penetrate the impact depth at different depths into the oil well end. The impact heads can thus have different ball diameters, for example when using impact heads with a spherical surface.

It can be provided that a spherical, hemispherical or part-spherical impact head has a diameter which is greater than the diameter of the oil well, in particular up to 1% larger, at least 1% larger, preferably at least 2% larger, particularly preferably we - at least 5% greater, for example at least 10%, 15%, 20% or even at least 50% greater than the diameter of the oil well.

In a further development it can be provided that a changing device is used to replace the impact heads.

In particular, a changing device may be provided with a magazine for exchanging the striking heads and / or the striking tool and / or the striking device in order to vary the diameter of the impact head used between two strokes on the same oil boring end.

A changing device for exchanging impact heads of a striking tool can be designed, for example, as a rotatable drum.

In a development of the invention, it may be provided that a ball body is pressed through at least a portion of the oil hole for work hardening of the oil hole end.

As a result, the inner walls of the oil well, in particular in the field of oil drilling consignment, can be work hardened. In order to achieve effective strain hardening, it is advantageous if the ball body is slightly larger than the diameter of the oil well to effect the desired strain that results in strain hardening.

The spherical body can be a striking head of a striking tool. The impact tool, which can be used in principle for impact hardening, can thus also be used for work hardening of the inner walls of the oil hole, if the impact tool is designed such that it can penetrate into the oil hole with the impact head. In particular, when the ball body is fixed during the pushing through the oil hole on the impact tool, as exact as possible alignment of the impact tool along the central axis of the oil hole is advantageous. Preferably, the ball body is removed after pushing into the portion of the oil hole again from the oil hole, z. B. pulled out.

In a development, it can be provided that the spherical body is pressed pulsating or uniformly into the at least one section of the oil hole.

The spherical body, for example, by successive bursts of force, which are generated for example by the percussion piston of a striker, pushed ever deeper into the oil hole (and possibly pulled out again). However, the ball body can also be introduced into the oil hole (and possibly pulled out again) to its final depth by a single pushing or pushing movement. The depth to which the oil well is preferably work hardened (or the depth of the oil well consignment) may be determined based on simulations and / or calculations and / or series of trials of the particular type of crankshaft. The at least one cylindrical section of the oil bore to be consolidated can also be determined on the basis of simulations and / or calculations and / or test series of the respective crankshaft type.

It can also be provided to push the ball body even deeper into the oil hole beyond the extent of the oil drilling end, for example also to press it completely into the oil hole.

Usually, the connection of the oil circuit of the crankshaft is made with the oil circuit of the engine block on the centrally rotating main journals. Starting from the main journals there is an oil distribution to the connecting rod journals. For this purpose, as a rule, connecting bores are provided, which connect the oil bores of the main bearing journals with the oil bores of the connecting rod journal, so that the eccentrically running connecting rod journals are also supplied with oil.

In a further development of the invention can be provided that the ball body is pressed into the oil hole of one of the connecting rod journal and passes from there directly or via a connecting hole to an oil bore of one of the adjacent main journals, wherein the connecting bore and / or the oil hole of the main journal Inner diameter which is at least as large as the outer diameter of the spherical body.

Since the ball body for the work hardening preferably has to be slightly larger than the diameter of the oil hole itself, the challenge arises of removing the ball body from the oil hole after work hardening. If the oil hole runs completely through the pin, the ball body on the back of the pin may possibly be pushed out of the oil hole again. If the oil hole does not extend completely through the spigot, provision may be made for the ball body to be withdrawn backwards out of the oil hole when work hardening is completed, but this may cause problems.

The inventors have now developed a method according to which the ball body is first pressed through the oil hole of the connecting rod journal until it encounters a corresponding connection bore or an oil bore of an adjacent main journal. If the connecting bore or the oil hole of the main journal have a larger diameter than the ball body, the ball body can thus be removed via an adjacent main journal again because the ball body through the connecting hole or the oil hole of the main journal and roll out of the mouth of the oil Main journal can fall out. It can also be provided to remove the ball body after pressing in the oil hole in another way, for example by pressure is built up in the oil supply channels, for example pneumatically or hydraulically, whereby the ball body can be pushed out of the section of the oil hole again.

It can be provided that the ball body is pressed by a plunger, which is not fixed or which is loosely connected to the ball body, in the portion of the oil hole.

It can also be provided that the ball body is first fixedly secured to the plunger and is released only during or after the complete impressions in the oil hole. As mentioned above, the ball body can also be a striking head of a striking tool. The impact tool can be designed such that the impact head can be released or discarded. In a further development of the invention it can be provided that the impact tool is introduced with at least one impact head in the oil hole, after which the at least one impact head radially out of the impact tool and against an inner wall for strain hardening of the oil well end and / or the at least one cylindrical portion of the oil hole the at least one cylindrical portion of the oil hole and / or pressed against the inner wall of the oil well end.

It can therefore be provided with radially telescopically deliverable impact heads a radially telescoping trained impact tool or a deflection tool. In this way advantageously any portion (or any portions) can be work-hardened within the oil well, preferably impact-strengthened. The impact tool can this be inserted into the desired depth in the oil hole, after which the at least one impact head is pressed to solidify the oil hole against the inner wall of the oil hole. In principle, it should be pointed out that the impact tool described in this section can also be used for work hardening, preferably impact hardening of the transition radius and / or bevel, even if the impact tool is described above and below only for machining the cylindrical section for better understanding. It can be provided, in particular, that the at least one striking head is pressed radially outwardly orthogonal to a central axis of the impact tool or the center axis of the oil bore. However, the at least one impact head may be urged radially outward at any angle relative to the center axis of the impact tool or oil hole. In order to solidify the inner surface or the inner wall of the oil hole in the region of the cylindrical portion as completely and uniformly as possible, it can be provided to rotate the impact tool during solidification continuously or periodically or clocked in the oil hole around the central axis of the oil hole. Furthermore, it can be provided to move the percussion tool during solidification continuously or intermittently or clocked axially along the central axis of the oil hole.

It may be intended to use two, three, four, five, six or more impact heads to solidify the cylindrical section. Preferably, the impact heads may be arranged uniformly about a central axis of the impact tool to uniformly solidify the inner wall of the oil well, starting from the central axis of the oil well. If more than one impact head is used, rotation of the striking tool in the oil hole may be omitted or the required angular range for the rotation may be reduced.

At least one support device can be provided in order to support the impact tool within the oil bore on its inner wall, in particular when only one impact head is used. The support means may be formed of a material described in the context of the above-mentioned support element.

It can also be provided to provide a plurality of axial planes, each with at least one impact head in the impact tool, for example, two, three, four, five, six or more levels to increase the process speed in the solidification of a correspondingly long cylindrical portion or the need to avoid an axial movement of the impact tool during solidification partially or completely. It can be provided to press the at least one impact head with continuous pressure or impact strengthening against the inner wall.

In a development, it may be provided to push the at least one impact head hydraulically, pneumatically or electromechanically out of the impact tool.

An electromechanical design can in particular be realized by using an electromechanical actuator which converts one or more electrical signals into a mechanical movement or a correspondingly suitable physical variable. Also, any combination of a hydraulic, pneumatic, electrical and / or mechanical design may be provided.

In an alternative development it can be provided that the at least one impact head is pressed out radially from the impact tool mechanically using at least one wedge or at least one ball screw drive. For example, a ball screw may be provided on both sides of nuts are arranged in the manner of impact heads, which can be moved on the ball screw in the direction of the inner wall of the oil hole. In particular, a conical ball screw can be provided, which is drivable by means of a spindle which is axially inserted into the oil hole.

In one embodiment of the invention it can be provided that the crankshaft is first rotated for striking hardening of one of the oil wells and / or one of the cylindrical portions of the oil holes by means of a drive means along a direction of rotation in an impact position, after which a locking device is used to the crankshaft in the To stop impact position, after which the percussion force is introduced into the oil well end and / or in the cylindrical portion of the oil hole by the impact tool.

As a result, (parasitic) shear stresses can largely, if not completely, be avoided. Furthermore, it can be prevented that the crankshaft undesirably turns when the impact tool is not precisely aligned.

By the locking device, the impact force can be introduced particularly targeted in the desired area. This is possible because the crankshaft can not unintentionally twist along or against the direction of rotation when hitting the striking tool.

In particular, a high-precision work or impact hardening can be ensured by the locking device. The impact positions as well as the impact distances can be implemented in a very targeted manner and with minimal tolerances.

In a locking device may be a device which locks the crankshaft preferably non-positively and / or positively or engages with this goal in the drive train or in the device. Preferably, a non-positive locking is provided, after which the locking force is selected such that a rotation of the crankshaft when introducing the impact force is avoided or at least suppressed.

The locking device may be a hydraulically, pneumatically and / or electrically operated locking device. The locking device preferably has one or more brake shoes, for example two brake shoes, three brake shoes, four brake shoes or more brake shoes.

The locking device is preferably attached to the workpiece drive unit. For example, the locking device on a jaw chuck or a clamping flange, a mounting flange or a face plate of the workpiece drive device or be arranged directly on the motor or the drive.

In particular, when impact hardening of inclined oil holes, the use of a locking device may be advantageous to prevent the crankshaft from twisting in an oblique stroke on the oil hole.

Usually, the oil holes, starting from the respective running surface of the pin, extend perpendicularly through the pin or onto the center axis of the corresponding pin. However, the oil holes can also run obliquely through the respective pin, for example, when an oil hole of a connecting rod journal is to be connected without an additional connection bore with the oil hole of a main journal.

The method according to the invention is preferably used for work hardening (in particular for impact hardening) of a vertical oil bore. However, the invention can also be used for the consolidation of inclined oil holes, the impact tool then preferably also can act perpendicular to the oil well. However, the impact tool in this case or in principle can also be placed obliquely. Preferably, the central axis of the striking tool is aligned coaxially with the central axis of the oil hole to be solidified, so that the applied impact force along the central axis of the oil bore extends.

It may be necessary to use support aids to prevent slipping or kinking of the impact tool. In one embodiment of the invention can be provided that for the operation of the drive device, a position control is used to rotate the crankshaft in the impact position, after which the crankshaft is preferably rotated stepwise or clocked.

With a position control or position control, a point-to-point movement of the crankshaft can thus be achieved. For example, a position control can be used to rotate the crankshaft step by step or clocked from one impact position to the next impact position. In the simplest case, a PTP control or point control can be provided for this purpose.

The drive device may comprise a motor, in particular an electric motor. In principle, the electric motor can be any desired electric motor, for example a three-phase motor (in particular a three-phase asynchronous machine), an AC motor, a DC motor or a universal motor.

Preferably, a stepper motor can be used. It is also possible to provide a two-part drive device in which, for example, a motor is provided at each end of the crankshaft, ie a synchronous drive or double-sided drive of the crankshaft. In one embodiment of the invention can be provided that the control of the drive device and the control of the locking device are synchronized with each other such that the locking device locks the crankshaft only when the crankshaft is stationary in the impact position.

The locking device can in principle, with appropriate design, for example in a traction-based design, also be used for braking the rotational movement of the crankshaft. However, it is particularly preferable to use the locking device only for locking the crankshaft in the impact position, whereby the dynamics or rotation of the crankshaft is influenced only by the drive device. That is, a torque that leads to an acceleration of the crankshaft (or to a deceleration), should preferably be introduced exclusively by the drive device. For example, the control of the drive device (eg, a position control) and / or the control of the locking device can then be of particularly simple construction. It may therefore be sufficient to synchronize by appropriate time management only the times at which the drive device and locking device act on the crankshaft. Preferably, therefore, the drive device and the locking device do not simultaneously act on the crankshaft.

In one embodiment of the invention may also be provided that the control of the locking device and the control of the at least one impact tool are synchronized with each other such that the at least one impact tool the impact force in the at least one oil well end and / or in the cylindrical portion of the oil hole the crankshaft when the crankshaft is locked in the impact position.

As a result, undesired shear stresses can be completely avoided. The synchronization of the controls of the drive device, locking device and / or the at least one impact tool can also be such that overlap the times or time periods in which the individual components act on the crankshaft, at least partially. As a result, a faster timing of the entire process can be achieved. In one embodiment of the invention can be provided that the drive device is designed as a direct drive.

Preferably, a drive device is provided without a clutch. In the present case, a direct drive is understood to mean drives in which the motor, preferably an electric motor, and the driving shaft are connected or coupled directly or without translation. In particular, a transmission can be dispensed with. When using the method according to the invention, it is preferably also possible to dispense with a coupling, in particular a slip clutch. A slip clutch, sometimes for the protection of components, is provided, for example, in the method according to EP 1 716 260 B1, in order not to damage the drive device or the device when the crankshaft is forcibly stopped due to the impact of the impact head. Such damage is excluded in the presently described method, whereby the slip clutch may be unnecessary.

As a result, the structure of the drive device is particularly simple and therefore economical.

In one embodiment of the invention may be provided in particular that the locking device and the drive means are arranged separated from each other.

The locking device is preferably not as a brake assembly within the drive device, which may be required, for example, for the position control formed. Usually, no braking arrangement is provided in a drive device which comprises an electric motor and performs a point-to-point operation via a position control or regulation, since the torques are generated by voltage and / or current regulation of the electric motor. If, however, the drive device comprise a conventional braking device, it may optionally be provided that the locking device according to the invention is additionally provided for this purpose and designed as an assembly independent of this.

In principle, the locking device can also be arranged separated within the drive device. Also in this case, these are preferably independent components which are spatially separated and / or functionally independent. In an alternative variant, which is not preferred, a braking device of the drive device can be used. For this purpose, this is suitable interpreted, so that the crankshaft is not twisted when introducing the impact force.

In one embodiment of the invention may further be provided that the locking device indirectly locks the spa at by the locking device a rotatable fastening device, preferably a mounting flange or a clamping flange of the fastening device, on which or on which the crankshaft is fixed arrives.

Instead of the mounting flange or in addition to the mounting flange, the fastening device may also include a face plate or other clamping means. In particular, a face plate with a plurality of clamping jaws, for example, two, three, four, five, six or more jaws, may be provided. As a result, crankshaft types with different diameters can be defined.

Usually, the crankshaft is rotatably fixed for the processing thereof via a fastening device on a drive shaft.

In order to lock the crankshaft in its impact position, the locking device can in principle engage an arbitrary position, which is mechanically coupled to the drive device or to the crankshaft. For example, the locking device can act on the crankshaft itself, within the drive device z. B. attack on the drive shaft, outside the drive device z. B. attack on the drive shaft or particularly preferably on the fastening device, in particular a mounting flange or a face plate or other clamping means, attack.

In one embodiment, it can be provided, in particular, that the locking device engages in the region of an outer circumference on the fastening device or on the fastening flange or on the face plate or on the clamping flange. Because the locking device engages in the region of an outer circumference of a disk or shaft, the locking forces to be applied or necessary can be smaller. Depending on the radial position of the locking device, based on the axis of rotation of the drive shaft, correspondingly less force is required to block a torsion, the greater the radial distance from the axis of rotation. It is particularly advantageous if the locking device engages only when the crankshaft is already stationary in the impact position.

In principle, the locking device can also engage at several points within the device. For example, it can be provided that the locking device engages at a suitable point in each case in the region of both ends of the crankshaft, for example on fastening flanges located there.

It may also be provided a support in the manner of a tailstock to rotatably support or fix the crankshaft at its end remote from the drive means end. The locking device can then attack, for example, in the region of the drive device or drive shaft and / or in the area of the support. Preferably, in this case, the locking device also engages the fastening device, preferably a fastening flange, as described.

In one embodiment of the invention can be provided that the locking device is designed to prevent rotation of the crankshaft opposite and / or in the direction of rotation of the crankshaft. The impact pressures, which are converted by the percussion piston to the impact force, depending on the operation - between 10 and 300 bar, preferably between 30 and 180 bar, and more preferably between 50 and 130 bar, amount.

The temperature in the region of the crankshaft segment or transition radius to be machined should preferably not be higher than 65 ° C; values between 12 ° C and 25 ° C are preferred.

In the method according to the invention for work hardening a crankshaft, in addition to the work hardening of the at least one oil well end and / or the at least one cylindrical section of the oil well, before, after or simultaneously with the solidification of the at least one oil well end and / or the at least one cylindrical section of the oil well Schlagverfestigung of transition radii of the crankshaft, in particular transitional radii between connecting rod journal and crank webs and / or transition radii between the main journal and the Kurbelwan- gene of the crankshaft, be provided.

Features and method steps that have been described above with respect to the impact hardening of the oil well endings or the cylindrical sections can, if this is not technically excluded, also be provided for the impact hardening of the transition radii between connecting rod journal and crank webs or main journal and crank webs.

In one embodiment of the invention concerning the impact hardening of the transition radii between connecting rod journal and crank webs and main journals and crank webs, the at least one impact tool with a periodicity, preferably with a beat frequency of 0.5 Hz to 30 Hz, more preferably with a timing of 0.5 Hz to 5 Hz and very particularly preferably with a cycle of 0.5 Hz to 3 Hz, perform a striking motion or bring the impact force.

Of course, other timings, for example, beat frequencies between 0.1 Hz and 50 Hz, may be provided, but the above values are particularly suitable.

The crankshaft usually has transition radii at all transitions or cross-sectional changes. This is especially true for cross-sectional changes between journals and crank webs. But transition radii can also for any other cross-sectional changes, in particular for changes in cross section at the end portions of the crankshaft, z. B. at a transition to a

Flange, a disc or a shaft, etc. may be provided. A transition radius of the crankshaft whose fatigue strength is to be improved, thus need not necessarily exist between a connecting rod journal and a crank arm or a main journal and a crank arm, but may be located at any point of the crankshaft. The terms "connecting rod journal", "Main journal", "flange", "pin" and / or "crank arm" can accordingly be reinterpreted by a person skilled in the art.

The crankshaft can have different types of transition radii, for example, fillets, for example in the form of a basket, or else undercut or deposited radii or radii with transitions. The transition radii can, for example, pass tangentially into the journal positions or running surfaces of the main and connecting rod journal.

This also applies to transitions to flanges, cones and other geometrical changes in cross section - both for tangent and deposited radii.

In one embodiment, it may be provided that the impact hardening of the transition radii between connecting rod journal and crank webs and / or main journal and crank webs is such that overlap the impact impressions of a percussion head of the percussion tool along the annular transition around the connecting rod journal or main journal respective transition radius defined.

In particular, when the impact impressions of a percussion head are to overlap along the respective transition radius of the crankshaft which revolves in an annular manner around the pin, d. H. if the impact positions are closely spaced, it is necessary to apply the impact force in a highly precise and targeted manner. Without the locking device described above, this is difficult because the crankshaft would at least partially turn back when introducing the impact force of a stroke position in the previous impact position when the impact head penetrates into the impact impression of the previous blow. Since it has been shown that by overlapping impact impressions or closely arranged and precisely defined impact positions can produce a particularly effective increase in fatigue strength and fatigue strength and Torsionswechselfestigkeit, the use of a locking device in combination with the introduction of closely spaced and / or precise impact distances in particular such that the impact impressions overlap or overlap, particularly advantageous.

The invention also relates to a device for impact hardening of a crankshaft, the crankshaft having connecting rod journals, main bearing journals and crank webs, and wherein the connecting rod journals and the main bearing journals have oil bores. According to the invention is provided with respect to the device that at least in an oil well end of one of the oil holes and / or in at least one cylindrical portion of the oil wells an impact force is introduced by means of a percussion head of a striking tool.

Features which have already been described in connection with the method according to the invention are of course also advantageously implementable for the device according to the invention - and vice versa. versa. Furthermore, advantages which have already been mentioned in connection with the method according to the invention can also be understood as related to the device according to the invention - and vice versa. In one embodiment of the device may also be provided a drive means to rotate the crankshaft in a striking position. Further, a locking device may be provided to lock the crankshaft in the impact position, wherein further at least one impact tool is provided to bring in the impact position an impact force in the at least one oil well end and / or in the at least one cylindrical portion.

The device can also be designed to introduce impact forces in transition radii between connecting rod journal and crank webs and / or transition radii between the main journal and the crank webs of the crankshaft or transitions to flanges, pins and other geometric cross-sectional changes of the crankshaft - both tangent and deposited radii.

It can be provided a control and / or regulating device, which includes the controls of the locking device, the drive device and / or the at least one impact tool.

The control and / or regulating device can be designed as a microprocessor.

Instead of a microprocessor can also be provided any further means for implementing a control and / or regulating device, for example one or more arrangements of discrete electrical components on a circuit board, a programmable logic controller (PLC), an application-specific integrated circuit (ASIC) or another Programmable circuit, for example, a Field Programmable Gate Array (FPGA), a programmable logic device (PLA) and / or a commercial computer.

The invention also relates to a computer program with program code means for carrying out a method as described above, when the program is executed on a control and / or regulating device, in particular on a microprocessor.

In principle, some of the components of the device according to the invention may correspond in their construction to the device according to EP 1 716 260 B1, for which reason the disclosure content of EP 1 716 260 B1 is completely integrated into the present disclosure by referencing.

The invention also relates to a crankshaft produced by a method as described above. The crankshaft according to the invention differs from conventional crankshafts in particular in that their oil well endings and / or the cylindrical sections of the oil wells are work hardened, preferably impact-strengthened.

In addition, if the transition radii between the connecting rod journal and the crank webs and / or the transition radii between the main journal and the crank webs of the crankshaft were solidified, a characteristic hardening of the crankshaft may result, especially when a locking device is used and overlap the impact distances and thus the impact marks of the individual strokes ,

Embodiments of the invention will be described in more detail with reference to the drawing.

The figures each show preferred embodiments in which individual features of the present invention are illustrated in combination with each other. Features of an exemplary embodiment can also be implemented independently of the other features of the same exemplary embodiment and can accordingly be readily connected by a person skilled in the art to further meaningful combinations and sub-combinations with features of other exemplary embodiments.

In the figures, functionally identical elements are provided with the same reference numerals.

They show schematically:

1 shows an overall view of a device according to the invention for carrying out the method in a first embodiment;

2 shows an exemplary flowchart of the method according to the invention;

3 shows a perspective view of a part of the device according to the invention for carrying out the method in a second embodiment;

Fig. 4 shows a beating device with a percussion tool and a percussion head with spherical

Surface in enlarged view according to detail "A" of Fig. 1;

5a shows a striking device with a percussion tool with two impact heads each having a spherical surface in the solidification of straight-running oil holes.

FIG. 5b shows the impact device of FIG. 5a during the consolidation of obliquely running oil bores; FIG. 6 shows a detail of a crankshaft with exemplary oil bores and with a connection bore between a vertically extending oil bore of a connecting rod journal and a vertical oil bore of a main journal;

FIG. 7 shows an exemplary oil well end of an oil well and a schematic illustration of impact hardening using impact heads of different sizes; FIG.

Fig. 8 shows an example of impact strengthening with a striking head having a molding section;

9 shows an example of impact hardening with a striking head, wherein a transition radius or a reduction is simultaneously introduced into the oil hole end by the impact head; 10 is an obliquely arranged impact tool in a further embodiment for solidifying a slanted oil hole.

Fig. 1 1 shows an oil hole in a sectional view with a transition radius, a chamfer and a cylindrical portion;

12 is a pneumatic / hydraulic or electromechanical impact tool for work hardening a cylindrical portion of an oil hole.

13 shows a pneumatic / hydraulic or electromechanical impact tool for work hardening a cylindrical section of an oil bore with impact heads arranged in several height planes; and

14 shows a striking tool for work hardening a cylindrical section of an oil hole by means of a wedge and several impact heads.

The device shown in Figure 1 in an overall view basically corresponds in its construction to the devices according to DE 34 38 742 C2 and EP 1 716 260 B1 with a beating device 1, which is why in the following only on the essential parts and the differences from the prior art will be received.

In the exemplary embodiment, the method according to the invention for strain hardening is illustrated by means of a impact hardening process. However, this is not restrictive. The method according to the invention can also be realized with another strain hardening process. The device has a machine bed 2 and a drive device 3. The drive device 3 is used to bring or rotate a crankshaft 4 along a direction of rotation in an impact position. The crankshaft 4 has connecting rod journal 5 and main journal 6, between which each crank webs 7 are arranged on. Transverse radii 8 (cf., FIGS. 4 to 6) are formed between connecting rod journal 5 and crank webs 7 and between main bearing journal 6 and crank webs 7 or generally between cross-sectional transitions of crankshaft 4. On the side facing the drive device 3 side of the crankshaft 4, a fastening device 9 is provided, which has a clamping disk or a mounting flange 10. On the side facing away from the drive device 3 side of the crankshaft 4, a support 1 1 is preferably provided in the manner of a tailstock having a further fastening means 9 to receive the crankshaft 4 rotatable or rotatable set. Optionally or in addition to the support 1 1, a Lü- nice, which is positioned at a rotationally symmetrical location, may be provided.

According to one embodiment of the invention, a locking device 12 is provided which engages in the region of an outer circumference of the fastening device 9. In principle, the locking device 12 can be arranged at any point within the device in order to apply a locking force to an output shaft of the drive device 3 or an hereby identical input shaft 13 of the fastening device 9 and thus to the crankshaft 4. The locking device 12 can also attack at several points of the device. By way of example, a second part of the locking device 12 is shown in dashed lines in engagement with the fastening device 9 in the region of the Abstützung 1 1.

The locking device 12 is based for example on a non-positive locking using a brake shoe assembly 14 shown only schematically.

The striking device 1 shown in FIG. 1 is a striking device 1 for impact-hardening at least one oil-boring end 30 (cf., in particular, FIGS. 7 to 9) of an oil bore 31 (compare FIGS. 4 to 4 (m)) and / or at least one cylindrical section 38 (see Figure 1 1) one of the oil holes 31st However, the illustrated impact device 1 can also be designed to impact-bond at least one transition radius 8 between a connecting rod journal 5 and a crank arm 7 and / or at least one transition radius 8 between a main journal 6 and a crank arm 7 of a crankshaft 4. It is also possible to provide a plurality of impact devices 1, wherein at least one of the impact devices 1 is designed to solidify the oil well endings 30 and / or the cylindrical section 38 and at least one further impact device is designed to provide the transition radii 8 between connecting rod journal 5 and crank web 7 or 7 to solidify between main journal 6 and crank arm 7. In principle, a locking device 12 for the operating principle of the invention is not required, but may be advantageous, for example, for impact hardening of obliquely extending oil holes 31 to prevent rotation of the crankshaft 4 when introducing the impact force. In Figure 1, a displacement and adjusting device 15 is further shown, which is intended to move the exemplary illustrated striker along the longitudinal axis of the crankshaft to the striker 1 according to the connecting rod journal 5 or the main bearing pin 6, the oil hole or oil well end impact should be positioned. FIG. 2 illustrates an example flowchart for an exemplary method that may consist of four steps (rotate, lock, beat, release). The step of locking and releasing is optional in the present case, but advantageous.

For the operation of the drive device 3, which preferably comprises an electric motor, a control can be used to rotate the crankshaft 4 in the respective impact position, after which the crankshaft 4 is preferably rotated stepwise or clocked.

After the crankshaft 4 has been rotated by the drive device 3 in the impact position, the crankshaft 4 is first locked by the optional locking device 12 in the impact position.

Subsequently, a striking force is introduced into at least one oil bore end 30 of an oil bore 31 of the crankshaft 4 and / or into at least one cylindrical portion 38 of an oil bore 31 of the crankshaft 4 by at least one striking tool 16 (cf., FIG. 4, FIGS. 5a / 5b and 10) , In addition, an impact force in at least one transition radius 8 of the crankshaft 4 can also be introduced by the same or at least one (further) impact tool.

Preferably, the control of the drive device 3 and the control of the locking device 12 are synchronized with each other such that the locking device 12, the crankshaft 4 is only locked when the crankshaft 4 is stationary in the impact position.

Furthermore, the controls of the locking device 12 and the at least one impact tool 16 (or the at least one impact device 1) can be synchronized such that the at least one impact tool 16, the impact force in the oil well 30 and in the cylindrical portion 38 of the crankshaft 4 introduces when the crankshaft 4 is locked in the impact position. Subsequently, the locking of the crankshaft 4 is released again.

The method can then be repeated as often as desired for the same oil well 30 or the same oil well 31, for example, by a slight modification of the impact position and / or the impact angle. After an oil well 30 and / or a cylindrical portion 38 has been impact-solidified in a desired manner, the impact tool 16 or the entire impactor 1 can be attached to the next to be solidified oil well 30 and to the next to be solidified cylindrical portion 38 (the same or a another oil well 31), after which the process comprising the steps of "turning", "locking" (optional), "beating" and "releasing" (optional) can be repeated.

In a similar manner, a control or a sequence for impact hardening of transition radii 8 between connecting rod journal 5 and crank webs 7 or between main bearing journal 6 and crank webs 7 may be provided. It can also be provided a common control.

The at least one impact tool 16 or the at least one impact device 1 can be the impact movement or the impact force with a periodicity, for example with a timing and / or beat frequency of 0.1 Hz to 50 Hz, preferably with a timing and / or beat frequency of 0 , 3 Hz to 10 Hz, more preferably with a clocking and / or beat frequency of 0.5 Hz to 5 Hz and very particularly preferably with a clocking and / or beat frequency of 0.5 Hz to 3 Hz, bring. It can be provided that several (at least two) blows are introduced into an oil bore 31 with said beat frequency or the solidification of transition radii 8 between connecting rod journal 5 and crank webs 7 or transition radii 8 between main bearing journals 6 and crank webs 7 the beat position with said clock is changed, after which one or more blows are performed.

To carry out the method, a control and / or regulating device 29, preferably comprising a microprocessor, may be provided. The control and / or regulating device 29 may, for example, also include or implement and / or synchronize the controls of the drive device 3, the locking device 12 and / or the at least one impact tool 16.

In particular, a computer program with program code means can be provided in order to carry out the method according to the invention if the program is executed on a control and / or regulating device 29, in particular on a microprocessor.

FIG. 3 is a fragmentary perspective view of a further device for carrying out the method according to the invention, albeit without a beating device. The device of FIG. 3 is essentially identical to the device of FIG. 1, for which reason reference will be made below only to the essential differences.

Again, a drive device 3 is provided. In the embodiment of FIG. 3, an optional locking device (not visible) is also arranged inside the drive device 3. Although the locking device is preferably arranged as shown in FIG. 1, the locking device can therefore also be accommodated within the drive device 3. It is, however nevertheless provided that the locking device is controlled separately from the drive device 3. According to FIG. 3, the locking device is not part of the drive device 3. The drive device 3 may optionally additionally have its own braking device. Further, a fastening device 9 is provided which has a mounting flange 10 and an attached face plate with clamping jaws for fixing the crankshaft 4. The face plate with the clamping jaws of the fastening device 9 is adjustably arranged on the mounting flange 10 on an alignment means 17, whereby the longitudinal axis C _K w of the crankshaft 4 can be displaced relative to the axis of rotation C of the drive shaft 13.

The crankshaft 4 of Figure 3 has a different from the crankshaft 4 of Figure 1 configuration, but basically also includes connecting rod journal 5, main journal 6 and crank webs. 7

In Figure 3 (as well as in Figure 1) can be provided at the end facing away from the drive means 3 end of the Kur- shaft 4, a further fastening means 9, but this can also be omitted.

FIG. 4 shows, by way of example, a beating device 1 of FIG. 1 in greater detail. The method for impact hardening can in principle be implemented with any impactor 1. However, the impact device 1 described below is particularly suitable. It has a base body 18, which can be provided with a prismatic system according to the radius of the crankshaft segment to be machined and preferably has guides 19 which guide a striking tool 16 and give them a corresponding freedom in the support angle about a deflection unit 20 which corresponds to FIG Adaptation to the dimensional conditions of the crankshaft 4 is advantageous. At the front end of the impact tool 16, a ball is arranged as a striking head 21, d. H. the impact head 21 has a spherical surface for impact hardening. An intermediate part 22 establishes the connection between a percussion piston 23 and the deflecting unit 20, which transmits the impact energy to the percussion tool 16. The intermediate part 22 may also be omitted if necessary.

In order to increase the effectiveness of the impact, a clamping prism 24 can be fastened by means of springs with adjustable clamping bolts with clamping nuts on the side of the journal 5 facing away from the main body 18 (not shown in detail). Here are also other constructive solutions possible.

By arranging a plurality of impactors 1 over the length of the crankshaft 4 to be machined, several to all regions or oil bores 31 of the crankshaft 4 can be processed simultaneously if required.

In the crankshaft 4 shown in Figure 4 an oil hole 31 is shown in dashed lines in the connecting rod journal 5, which extends centrally and vertically in the connecting rod journal 5 and ends approximately in the middle of the connecting rod journal 5. For connection to the oil circuit of the engine block via an adjacent main bearing journal 6, a connecting bore 32 is provided. The connection bore 32 leads to 4, the impact device 1 and the impact tool 16 are aligned in the exemplary embodiment such that an oil well 30 of the oil hole 31 can be impact-solidified. For this purpose, the impact force is introduced by means of the impact head 21 of the impact tool 16 in the oil well 30.

For aligning the impact tool 16 on the oil well end 30 of the main body 18 of the beater 1 by two support members 33 (or a multi-part or circumferential support member) on the crank webs 7, which adjoin the connecting rod journal 5, supported. The support elements 33 can also serve to prevent the striking tool 16 from kinking or slipping off during the impact hardening of the oil drilling end 30.

In principle, a plurality, preferably a majority, particularly preferably all oil well endings 30 of the connecting rod journal 5 and / or the main journal 6 can be work-hardened or impact-hardened. Preferably, all oil well endings 30 of all connecting rod journal 5 are impact-hardened.

In Figures 5a / 5b, another impact device 1 is shown having a percussion tool 16, on which two impact heads 21 are arranged to offset two in the same pin 5, 6 axially along the main axis of rotation C _K w of the crankshaft 4 and axis of rotation C. to solidify arranged oil well shipments 30.

The impact device 1 of Figures 5a / 5b is basically similar to the impactor 1 of Figure 4 constructed and also shown only schematically. The impact device 1 of the figures 5a / 5b also has a deflection unit 20 in order to distribute the impact force generated by the percussion piston 23 via an intermediate part 22 on the impact heads 21. At the same time, the deflection unit 20 can serve to optimally align the impact tool 16 with the oil well endings 30. For support, one or more support elements 33 or a circumferential support element can again be provided, which in the present case are arranged between the impact tool 16 and the corresponding crank webs 7. A striking device 1 can basically be used for impact hardening of straight-running oil bores 31 (cf., FIG. 5 a) or for impact hardening of obliquely running oil bores 31 (cf., FIG. 5 b). Of course, this also applies if only one impact tool 16 and / or one impact head 21 and / or one oil bore 31 in a journal 5, 6 to be solidified. It can also be provided that for cold hardening an oil bore 31 or an oil well end 30, a spherical body 34 is pressed through at least a portion of the oil bore 31. This is shown schematically in FIG.

It can be provided that the spherical body 34 is pressed pulsating or uniformly in the at least one portion of the oil hole 31. The spherical body 34 may also be a already described impact head 21 act. Preferably, the ball body 34 is removed again from the oil hole 31 after solidification of the inner walls of the oil hole 31.

Figure 6 shows an exemplary section of a crankshaft 4, each having an oil hole 31 in a connecting rod journal 5 and a main bearing pin 6. Between the illustrated two oil holes 31, a connecting bore 32 is introduced. In subsequent operation of the crankshaft 4 can then be provided to close the mouth of the connecting bore 32 on a crank arm 7 with a sealant 35, so that the oil circuit is closed. Alternatively, one or both oil bores 31 may extend obliquely toward one another.

It may, as already stated above, be provided to solidify the oil well 30 of an oil hole 31 of the connecting rod journal 5 or the entire oil hole 31 of the connecting rod journal 5 or any cylindrical portion 38 on the inside or on the inner walls of the oil hole 31 by the Ball body 34 is pushed through the oil hole 31. For this purpose, the ball body 34 has a slightly larger diameter than the oil bore 31.

If, due to the application, it is necessary or advantageous to press the ball body 34 so deeply into the oil bore 31 that the ball body 34 can no longer be withdrawn or pulled out by the impact tool 16 or the withdrawal is considered unfavorable, it can be provided that the ball body 34 passes from the oil hole 31 of the connecting rod journal 5 directly or via a connecting bore 32 to an oil hole 31 of an adjacent main journal 6, wherein the connecting bore 32 and / or the oil bore 31 of the main journal 6 have an inner diameter which is at least as large as the outer diameter of the Spherical body 34.

Once the ball body 34 has thus been pushed so deep into the oil hole 31 that the ball body 34 meets the connecting hole 32, which has a larger diameter than the ball body 34 and the oil hole 31 of the connecting rod journal 5, the ball body 34 through the connecting hole 32 to the oil hole 31 of the main journal 6 arrive, for example, roll, from where the ball body from the crankshaft 4 can be removed again, although the oil hole 31 of the main bearing pin 6 has a larger diameter than the ball body 34th

Figure 7 shows an enlarged view of an oil well end 30. At the transition to the tread 36 of the corresponding pin 5, 6, the oil well end 30 on a transition radius R, which is impact-solidified. Instead of a transition radius R, the oil well end 30 at the transition to the tread 36 also have any reduction. However, the oil well 30 may be provided without a transition radius R or a reduction. It can also be provided that the oil well end 30 has a transition radius R and a chamfer 39, as shown in Figure 11, has. In Figure 7, an oil well end 30 of the oil hole 31 is also shown. In principle, the oil drilling consignment 30 may comprise only the mouth of the oil bore 31, that is to say, for example, the transition radius R and / or the chamfer 39 (cf., FIG. 8 and FIG. However, it can also be provided that the oil well end 30, which is to be work-hardened, projects into the oil bore 31 up to a depth T. The depth T can be determined by simulations, calculations and / or test series of the respective type of crankshaft.

It can be provided that impact strikes 21 of different diameters are used for impact hardening of the oil well end 30 in such a way that the impact heads 21 penetrate at different depths into the oil well end 30 during impact hardening.

For example, a change device 37 (shown only schematically) may be provided to select and / or replace the impact heads 21. In the embodiment of Figure 7 is indicated for this purpose that the changing device 37 exchanges the impact tool 16 to replace the impact heads 21. However, it may also be provided that the changing device 37, the impact heads 21 replaced directly or the entire impactor 1 replaced.

FIG. 7 also shows a striking head 21, which can be pressed as a spherical body 34 through the oil bore 31. For this purpose, the impact tool 16 can be designed, for example, to eject the impact head 21 or the ball body 34 after or during the indentation. Preferably, the inner walls of the oil bore 31 are work hardened at least to the depth T or extent of the oil well 30. The diameter of the ball body 34 is selected to be work hardening of the inner walls of the oil bore 31 greater than or equal to the diameter D of the oil bore 31. Finally, FIG. 8 shows a further oil drilling consignment 30, which only includes the transition radius R of the oil bore 31. For striking hardening, a striking head 21 is used which has a molding section whose shape is adapted to the transition radius R of the oil drilling end 30 to be consolidated. It is also a sinking or countersinking or a chamfer 39 and / or a transition radius R of an oil well 30 by a shaping impact tool 16 and a corresponding impact head 21 are generated by the Schlagverfestigung in the first place. Such a plastic deformation by a striking head 21 is shown in FIG. 9, a round or symmetrical striking head 21 being indicated; but it can also be a non-symmetrical impact head 21 (any desired ballot). By choosing a corresponding impact head 21, for example, a percussion head 21 having a mold portion, any reduction can be generated.

Finally, from Figure 10, a further impact device 1 can be seen, which is provided with only one impact tool 16. In the illustrated embodiment, the impactor 1 is not orthogonal to the central axis or main axis of rotation C _K w of the crankshaft 4 but obliquely thereto, namely such that the central axis or longitudinal axis L _{s of} the impact tool 16 is aligned coaxially with the central axis of the oil bore 31 in order to introduce the impact force along the central axis of the oil bore 31. Figure 1 1 shows a further oil bore 31 within a pin 5, 6 of a crankshaft 4 to clarify the terminology. The oil hole 31 shown in FIG. 11 has a transition radius R at the transition to the running surface 36 of the pin 5, 6, to which a chamfer 39 adjoins. In the exemplary embodiment of FIG. 11, the oil-bore orifice 30 is defined starting from the transition radius R to the depth T and therefore also comprises an upper cylindrical section 43 of the oil bore 31. According to the invention, it is possible to cold-strengthen the oil-hole orifice 30 to a depth T, ie the transition radius R, the chamfer 39 and the upper cylindrical section 43 of the oil bore 31. However, it is within the scope of the invention, only the transition radius R, only the chamfer 39, only the transition radius R and the chamfer 39 or only the chamfer 39 and the upper cylindrical portion 43 of the oil well 31 are work hardened.

It may also be provided, only one or more arbitrary cylindrical portions 38 estzu estzu inside the oil bore 31. An exemplary cylindrical section 38 is shown in FIG. The cylindrical portion 38 may comprise any large portion of the cylindrical portion of the oil hole 31. The cylindrical portion 38 may connect to the chamfer 39, but also be spaced from the chamfer 39. The cylindrical portion 38 may also be formed multiple times in the cylindrical part of the oil hole 31.

For solidifying a cylindrical portion 38 of an oil hole 31 different impact tools 16 can be used. Three exemplary embodiments are shown in FIGS. 12 to 14. It is provided in each case that the impact tool 16 is introduced with at least one impact head 21 in the oil bore 31 to a desired depth, after which for work hardening (preferably impact hardening) of the at least one cylindrical portion 38 of the oil bore 31 of at least one impact head 21 radially out of the Impact tool 16 out and against an inner wall 40 of the at least one cylindrical portion 38 is pressed.

In FIG. 12, the right-hand impact head 21 is shown in a position adjacent to the inner wall 40 only for clarity, while the left-hand impact head 21 is still in its initial position. Preferably, the impact heads 21 are pressed symmetrically outward. In order to secure the striking heads 21 in their starting position, corresponding shoulders etc. may be provided in the impact tool 16, as indicated in FIGS. 12 and 13.

In principle, any number of impact heads 21 may be provided. For example, one, two, three, four, five, six or even more impact heads 21, which are arranged in particular symmetrically about a center axis M of the striking tool 16. In the exemplary embodiment of FIG. 12, two impact shown heads 21, wherein a further impact head 21 (preferably another impact head pair) is indicated by dashed lines by way of example.

The impact heads 21 can also be arranged at different height levels, as shown in FIG. This makes it possible to edit a larger cylindrical portion without or with less axial adjustment of the impact tool 16.

In addition, it can be provided to rotate the impact tool 16 during machining along the central axis of the oil bore 31, in order to carry out the most uniform and complete machining of the inner surface of the oil bore 31. This is indicated in the figures 12 to 14 by corresponding arrows.

It can be provided that the at least one striking head 21 is hydraulically, pneumatically or electromechanically pushed radially out of the striking tool 16. The impact tool 16 may for this purpose have a corresponding compressed air or liquid supply 41. Alternatively, as shown in Figure 14, a mechanical adjustment of the at least one impact head 21 may be provided, for example by means of a wedge 42 or a ball screw drive (not shown). In Figure 14, an embodiment is shown in which a double wedge 42 is used, which secures the impact heads 21 simultaneously axially. But it can also be provided only a simple wedge (for example, only the upper half of the double wedge 42), if the impact heads 21 are otherwise secured against falling out of the impact tool 16.

Claims

P a n t a n s p r e c h e

Method for work hardening a crankshaft (4), which has connecting rod journals (5), main bearing journals (6) and crank webs (7), the connecting rod journals (5) and the main bearing journals (6) having oil bores (31),

d a d u r c h e c e n c i n e s that

at least one oil well end (30) of one of the oil wells (31) and / or at least one cylindrical portion (38) of one of the oil wells (31) is work hardened.

Method according to claim 1,

d a d u r c h e c e n c i n e s that

the oil well end (30) and / or the cylindrical section (38) is impact-hardened. Method according to claim 2,

d a d u r c h e c e n c i n e s that

in the oil well end (30) and / or in the cylindrical portion (38) a striking force by means of a striking head (21) of a striking tool (16) is introduced.

Method according to claim 2 or 3,

d a d u r c h e c e n c i n e s that

the oil well end (30) at the transition to a running surface (36) of the respective pin (5, 6) has a transition radius (R), wherein the transition radius (R) is impact-solidified.

Method according to one of claims 2 to 4,

d a d u r c h e c e n c i n e s that

the oil well end (30) has a chamfer (39), the chamfer (39) being impact-hardened.

Method according to one of claims 2 to 5,

d a d u r c h e c e n c i n e s that

two in the same pin (5, 6) arranged axially staggered Ölbohrungsendungen (30) simultaneously by means of a two impact heads (21) having impact tool (16) are impact-hardened.

Method according to one of claims 3 to 6,

d a d u r c h e c e n c i n e s that

the impact tool (16) is supported on at least one of the crank webs (7) for alignment with one of the oil well endings (30) and / or during impact hardening by at least one support element (33).

Method according to one of claims 3 to 7, characterized in that

the impact head (21) has a spherical surface for impact hardening.

Method according to one of claims 4 to 8,

d a d u r c h e c e n c i n e s that

the impact head (21) has a mold section, the shape of which is adapted to the transition radius (R) to be consolidated and / or to the chamfer (39) of the oil well end (30). 10. The method according to any one of claims 3 to 9,

d a d u r c h e c e n c i n e s that

during impact hardening of one of the oil well endings (30), a transition radius (R) of the oil well end (30) or a countersinking of the oil well end (30) by the impact head (21) is created.

11. The method according to any one of claims 3 to 10,

d a d u r c h e c e n c i n e s that

for impact hardening of the oil well end (30) impact heads (21) with different diameters are used, so that the impact heads (21) penetrate the impact depth at different depths into the oil well end (30).

12. The method according to claim 11,

d a d u r c h e c e n c i n e s that

a changing device (37) is used to replace the impact heads (21).

13. The method according to any one of claims 1 to 12,

d a d u r c h e c e n c i n e s that

for work hardening the oil well end (30), a ball body (34) is pushed through at least a portion of the oil well (31).

14. The method according to claim 13,

d a d u r c h e c e n c i n e s that

the ball body (34) is pulsed or evenly pressed into the portion of the oil hole (31).

15. The method according to claim 13 or 14,

d a d u r c h e c e n c i n e s that

the ball body (34) is pressed into the oil bore (31) of one of the connecting rod journals (5) and from there directly or via a connecting bore (32) to the oil hole (31) of one of the adjoining main journals (6), wherein the connecting bore (32) and / or the oil well (31) of the main journal (6) have an inner diameter which is at least as large as the outer diameter of the spherical body (34).

16. The method according to any one of claims 1 to 15,

d a d u r c h e c e n c i n e s that

a plurality, preferably a majority, more preferably all Ölbohrungsendungen (30) of the connecting rod journal (5) and / or the main bearing journal (6) are work hardened.

17. The method according to any one of claims 3 to 16,

d a d u r c h e c e n c i n e s that

the crankshaft (4) for impact hardening of one of the oil well endings (30) and / or one of the cylindrical sections (38) of the oil bores (31) is first rotated by a drive device (3) along a direction of rotation to an impact position, after which a locking device (12) is used to lock the crankshaft (4) in the impact position, after which by the impact tool (16) the impact force in the oil well end (30) and / or in the cylindrical bore

Section (38) of the oil hole (31) is introduced.

18. The method according to any one of claims 3 to 17,

d a d u r c h e c e n c i n e s that

the impact tool (16) is introduced into the oil bore (31) with at least one impact head (21), after which at least one impact head (31) is provided for work hardening the oil well end (30) and / or the at least one cylindrical portion (38) of the oil well (31). 21) radially out of the impact tool (16) and against an inner wall (40) of the at least one cylindrical portion (38) of the oil bore (31) and / or pressed against the inner wall of the oil well end (30).

19. The method according to claim 18,

d a d u r c h e c e n c i n e s that

the at least one impact head (21) is pushed out hydraulically, pneumatically or electromechanically radially from the impact tool (16).

20. The method according to claim 18,

d a d u r c h e c e n c i n e s that

the at least one impact head (21) is mechanically pushed out of the impact tool (16) mechanically using at least one wedge (42) or at least one ball screw drive.

21 A device for impact hardening a crankshaft (4), wherein the crankshaft (4) connecting rod journal (5), main journal (6) and crank webs (7), and wherein the connecting rod journal (5) and the main bearing pins (6) have oil holes (31) . characterized in that

in at least one Ölbohrungsendung (30) of the oil holes (31) and / or in at least one cylindrical portion (38) of the oil holes (31) an impact force by means of a striking head (21) of a striking tool (16) is introduced.

Crankshaft (4), produced by a method according to one of claims 1 to 20.