WO2018228795A1 - Method and device for the impact treatment of transition radii of a crankshaft - Google Patents

Abstract

The invention relates to a device for the impact treatment of transition radii (8) of a crankshaft (4), in particular transition radii (8) between connecting rod bearing journals (5) and crank webs (7) and/or transition radii (8) between main bearing journals (6) and the crank webs (7) of the crankshaft (4). The device comprises at least one impact device (1) which has a hammer piston (23), a deflecting unit (20), and at least one impact tool (16). The hammer piston (23) transmits an impact force onto the at least one impact tool (16) via the deflecting unit (20), and an impact head (21) of the at least one impact tool (16) introduces an impact force (FS) into the at least one transition radius (8) at an impact angle (α). The device is designed to adjust the distance (d) between a deflection point (UP) of the deflecting unit (20) and the front end of the impact head (21) of the at least one impact tool (16).

Description

 Method and device for impact hardening Überqangsradien a crankshaft

The invention relates to a device for impact hardening of transition radii of a crankshaft, in particular transition radii between connecting rod journal and crank webs and / or transitional radii between the main journal and the crank webs of the crankshaft according to the preamble of claim 1.

The invention also relates to a method for impact hardening of transition radii of a crankshaft. The invention also relates to a crankshaft.

Due to the steadily progressing development and increase in performance of internal combustion engines and emission requirements imposed on them, 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 percussion 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.

It is an object of the present invention to further develop methods and devices for impact hardening in order to further improve the fatigue strength of crankshafts. This object is achieved for the device by the features listed in claim 1 and for the method by the features listed in claim 8.

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 13.

The dependent claims and the features described below relate to advantageous embodiments and variants of the invention.

The device according to the invention for impact hardening of transition radii of a crankshaft, in particular transition radii between connecting rod journal and crank webs and / or transition radii between the main journal and the crank webs of the crankshaft comprises at least one impact device with a percussion piston, a deflection unit and at least one striking tool. The percussion piston transmits a force impulse to the at least one percussion tool via the deflecting unit, a percussion head of the at least one percussion tool introducing an impact force into the at least one transition radius at a striking angle. 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 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 diameter of 100 to 500 mm or more.

The crankshaft may have various types of transition radii, for example, fillets, for example, in a basket arch shape, or also undercut 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 geometric cross-sectional changes - both tangent and deposited radii.

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. For this purpose, the invention is particularly suitable. 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 whose fatigue strength is to be improved by the method according to the invention or the device according to the invention does not necessarily have to be between a connecting rod journal and a crank web or a main journal and a crank web, but can be arranged 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.

In the following, the invention will be described essentially on the basis of the hardening of transition radii between connecting rod journal and crank web and / or main journal and crank web. However, this is not restrictive and should only serve the better understanding or better readability. Insofar as reference is made to a transition radius in the context of the invention, this can basically be an arbitrary transition radius at any point of the crankshaft.

The introduction of an impact force can be understood to mean that a striking head of a striking tool or a so-called "beat" of the striking device strikes against the region of the cure shaft to be consolidated, in the present case a transition radius. The impact is targeted to the desired impact position along the annular radius around the pin transition radius. For this purpose, a percussion piston can be 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 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 possibly to partial geometric changes (cross-sectional changes).

The impact force in turn can be individually set or aligned individually by changing the impact angle to the maximum stress.

The device may optionally have a plurality of impact devices.

According to the invention, the device is set up to adjust the distance between a deflection point of the deflection unit and the front end of the impact head of the at least one striking tool. The deflection point may be the center point of the deflection unit or the axis of rotation / suspension of the striking tool or impact tools.

By the front end of the impact head is meant that part (or surface) of the impact head with which the impact head strikes the crankshaft for impact hardening.

Due to the distance between the deflection point and the front end of the impact head, the distance between the deflection point and the center of the impact head or the distance between the deflection point and the rear end of the impact head can be adjusted.

Because the distance between the deflection point of the deflection unit and the impact head is adjustable, the angle under which the impact force is introduced into the transition radius can be changed or adjusted. Preferably, the angle is chosen such that the impact force is introduced at an angle which is exactly adapted to the highest load during operation of the crankshaft body or the maximum load.

The solution according to the invention makes it possible to introduce the impact force at a preferred location and at a preferred angle. The methods and devices according to the prior art provide that in the striking solidification of a transition radius, the impact force is introduced in a predetermined fixed angle in the transition radii. For this purpose, a beating angle of approximately 45 ° is usually provided.

Depending on the application of the crankshaft, it may be advantageous to choose a different angle instead of a fixed impact angle of, for example, 45 °.

The highest loaded point of the crankshaft usually results from the engine operation or is determined by calculation models. For new approaches, the maximum loads from uniaxial loading and from biaxial, superimposed load are considered.

By means of the method according to the invention or the device according to the invention, a high-precision work or impact hardening can be ensured. By virtue of the fact that the impact forces can be deliberately introduced into a stress maximum of the transition radius and extend at an optimum angle, the impact force can optionally be reduced while the achievable fatigue effect remains unchanged. The device according to the invention is thus particularly efficient.

Due to the application of the impact forces, the fatigue strength of the crankshaft can be increased even further, should this be necessary, starting from the current possibilities in the state of the art. 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. Thus, for example, a crankshaft which has been hardened by induction hardening can be improved later with respect to its bending and torsional fatigue strength by introducing compressive residual stresses with the device according to the invention or the method according to the invention.

In a development of the invention it can be provided that the length of the at least one striking tool is adjustable, preferably telescopic.

For this purpose, the impact tool may be formed in the manner of a telescopic rail or have a telescopic extension. The at least one striking tool can also be designed as a telescopic tube. The invention is of course not limited to a particular type of telescopic extension or a certain type of telescoping to understand.

The length of the at least one impact tool can also be adjusted for example by means of a thread.

It can be provided that the length of the at least one impact tool is manually and / or actorically adjustable. For this purpose, for example, an electric motor, in particular a linear drive can be provided. In principle, however, the electric motor can be any desired electric motor, for example a three-phase motor, an AC motor, a DC motor or a universal motor. Preferably, a stepper motor can be used. In a further development of the invention, a changing device can be provided with a magazine in order to exchange the at least one impact tool and / or the impact head and / or the deflecting unit and / or the impact device by the distance between the deflection point of the deflecting unit and the front end of the impact head set the at least one impact tool to another value.

Due to the high impact forces, it is known that high mechanical loads act on the components of the impact device. In particular when using filigree components for adjusting the length of the at least one impact tool, the service life of the impact device or its components may be limited. If a magazine or a change device for the at least one impact tool and / or the impact head and / or the deflection unit and / or the

Impact device is provided, the impact device or the device can be designed to be particularly robust overall, as may be necessary to dispense with a telescoping of at least one impact tool. The distance between the deflection point of the deflection unit and the impact head of the at least one impact tool can thus be advantageously adjusted by the changing device with the magazine by replacing components of the impact device for length adjustment. It can also be provided that the distance between the deflection point of the deflection unit and the front end of the impact head of the at least one striking tool can be adjusted by using spacers or spacers with different dimensions.

In one embodiment of the invention, two or more impact devices may be provided, wherein the distance between the deflection point of the deflecting device and the front end of the

Impact head of a first impact device is not identical to the distance between the deflection point of the deflector and the front end of the impact head of a second impact device.

Thus, it is possible to provide a plurality of impact tools which can be used independently of one another, in particular by using a plurality of impact devices, each with one or more impact tools, which are able to introduce the respective impact forces into any transition radii of the crankshaft, wherein a corresponding synchronization with each other or between controls of the impact tools can be provided. The impact hardening of the crankshaft can thus also be particularly fast, since several impact devices can be used at the same time.

In one development of the invention, it can be provided that the at least one impact device has two impact tools, wherein the impact tools are arranged on the deflection unit such that each impact tool is assigned to a transition radius. It can therefore be provided that two impact tools are used in a common impact device, which preferably bring in impact forces in both transition radii of a connecting rod journal or a main journal simultaneously.

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

The striking tools can preferably be operated by a common percussion piston.

When using a plurality of impact tools and / or impact devices, a common pressure pulse device can be provided, which is able to generate the corresponding impact forces for the striking tools in a hydraulic, pneumatic, mechanical and / or electrical manner (jointly or individually) for the impact tools.

When using multiple impact devices can be provided that the respective distances between the deflection points and the impact heads are identical or at all Schlagwerkzeugen at least two striking tools differ from each other. Preferably, the respective distance between the deflection point of the deflection unit and the impact heads of two striking tools, which are identical for solidifying transition radii, which adjoin the same pin. In one development of the invention it can be provided that the impact angle between the longitudinal axis of the at least one impact tool and a perpendicular to the longitudinal axis of the crankshaft 5 ° to 80 °, preferably 10 ° to 70 °, more preferably 20 ° to 60 ° and particularly preferred 30 ° to 55 °, in particular 35 ° to 50 °. Preferably, in particular when the maximum stress is not known exactly, a beating angle of 45 ° can be provided.

In a further development of the invention may also be provided that the impact head has a radius whose size is 75% to 99% of the transition radius, preferably 85% to 98% of the transition radius and more preferably 85% to 95% of the transition radius.

The radius of the impact head may also be less than 75% of the transition radius or greater than 95% of the transition radius. The radius of the impact head can also coincide with the transition radius.

The impact head may preferably be formed substantially spherical, in particular in the front region or at the front end of the impact head, which beats or to solidify against the crankshaft. In principle, however, the impact head can have any desired geometry and can also be oval, hemispherical or flat, for example.

The invention also relates to a method for impact hardening of transition radii of a crankshaft, in particular of transition radii between connecting rod journal and crank webs and / or transition radii between the main journal and the crank webs of the crankshaft. The method also applies to transitions to flanges, cones and other geometric cross-sectional changes - both tangent and deposited radii.

Features which have already been described in connection with the device according to the invention are of course also advantageously implementable for the method according to the invention - and vice versa. Furthermore, advantages which have already been mentioned in connection with the device according to the invention can also be understood as related to the method according to the invention - and vice versa.

In a further development it can be provided that the impact angle is selected according to the course of a maximum stress of the transition radius, after which the course of the Beanspru- maxima on the basis of simulations and / or calculations and / or test series of the respective crankshaft type is determined.

The most heavily loaded areas of the crankshaft are preferably identified in advance. By means of the device according to the invention or the method according to the invention, the impact force can then be introduced in a targeted manner into the corresponding maximum load conditions. By taking into account the individual requirements for different crankshaft types and applications of the crankshafts, the crankshaft can be impact-hardened with particularly high precision by the adjustment according to the invention of the distance between the deflection point of the deflection unit and the front end of the impact head of the at least one striking tool.

By means of the method and the device according to the invention, not only the impact point but also the direction of impact can be determined. As a result, crankshafts can be produced whose fatigue strength, in particular their bending and Torsionswechselfestigkeit, is further optimized. Alternatively, the already available precision allows an already existing fatigue strength to be achieved by the use of low impact forces.

In a development of the invention, it can be provided that all transition radii between the connecting rod journal and the crank webs and / or all transition radii between the main bearing journal and the crank webs are impact-bonded at the same impact angle.

It is also possible for all transitions to flanges, cones and / or other geometric cross-sectional changes - both tangential and deposited radii - to be impact-hardened at the same impact angle.

It can therefore be provided that all transition radii of the crankshaft are impact-hardened under the same impact angle, the impact angle selected for this purpose being optimized with respect to the highest-loaded point of the crankshaft. But it can also be provided that all transition radii of the connecting rod journal are impact-bonded at a first impact angle and all transition radii of the main journals are impact-bonded under a second impact angle, the first and the second impact angle are optimized according to the respective highly loaded points or the course of the maximum stress ,

In an alternative development of the invention it can be provided that at least two transition radii between the connecting rod journal and the crank webs are impact-bonded under a different impact angle and / or that at least two transition radii between the main journal and the crank webs are impact-bonded under a different impact angle and / or in that at least one transition radius between the connecting-rod journal and the crank webs is impact-bonded at a different impact angle than a transition radius between the main journal and the crank webs. The impact angles can thus be set or optimized individually for each transition radius or for groups of transition radii. For example, different impact angles can be used simultaneously in one pivot point.

Finally, in a further development of the invention, it is also possible to provide for the impact angle to be changed during impact hardening of a transition radius circulating annularly around the connecting rod journal and / or the main journal.

Of course, this also applies to transitions to flanges, cones and / or other geometric cross-sectional changes - both tangent and deposited radii. It has been shown that this can achieve a further increase in the fatigue strength or fatigue strength and / or Torsionswechselfestigkeit.

For example, a different impact angle may be provided in the so-called bottom dead center of a connecting rod journal or in a defined region around the bottom dead center than in the remaining region of the transition radius.

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.

Experience has shown that after dynamic loading in the engine or on the test bench crankshafts can get non-propagating microcracks on the surfaces. These microcracks have no effect on the fatigue properties, but they can disturb the visual appearance.

Since the introduction of compressive residual stress can preferably take place to a depth of 15 mm, but even deeper, this means that in the surface region of the crankshaft, a removal of a few millimeters, for example from 0.1 to 3 mm, preferably 0.5 mm , without the flexural and torsional fatigue or the fatigue strength of the crankshaft suffers.

Investigations have shown that such measures can even slightly increase fatigue strength, for example by up to 5%. The removal of the surface can be done in various ways, such as by grinding, turning, milling, turn milling, peeling or polishing. In particular, if it is provided that the impact angle during the impact hardening of a transition radius is changed actorically, a control and / or regulating device, preferably comprising a microprocessor, be provided to control the corresponding actuators.

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.

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 at least two different impact angles are used for their solidification, resulting in a characteristic hardening of the transition radii.

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 shown 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; FIG. 2 shows a perspective view of a part of the device according to the invention for carrying out the method in a second embodiment; FIG.

3 shows a striking device with two impact tools in an enlarged view according to detail "A" of Fig. 1.

4 shows a striking device with two telescopic striking tools;

5 is an enlarged view of a transition radius and a striking tool with a

 Impact head, wherein the impact tool is aligned to a first impact angle;

6 is an enlarged view of a transition radius and a striking tool with a

 Impact head, wherein the impact tool is aligned to a second impact angle;

7 shows a impact-hardened transition radius, in which a first impact angle was used for impact hardening;

8 shows a impact-hardened transition radius in which a second impact angle was used for impact hardening; and

9 shows a impact-hardened transition radius, in which the impact angle during the impact hardening was varied along the transition radius surrounding the pin annularly.

The device shown in Figure 1 in an overall view basically corresponds in its structure to the devices according to DE 34 38 742 C2 and EP 1 716 260 B1 with one or more impact devices 1, which is why hereinafter only on the essential parts and on the differences to the prior Technology is discussed in more detail.

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. 3 and 5 to 9) 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, which has a further fastening means 9 to receive the crankshaft 4 rotatable bar 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.

The drive device 3 is able to set the crankshaft 4 along a rotation axis C in a rotational movement. It can be provided that the main axis of rotation C _K w of the crankshaft 4 is positioned off-center of the axis of rotation C of the drive device 3, as shown in Figure 1 and Figure 2. For this purpose, alignment means 17 (cf., FIG. 2) may preferably be provided in the region of the fastening device 9. It can be provided that the alignment means 17 a center axis of each to be solidified pin 5, 6 shift so that the central axis of the pin 5, 6 is located on the axis of rotation C.

For the drive device 3, a direct drive, preferably without a clutch, can be provided. An engine, preferably an electric motor, of the drive device 3 can thus be mechanically coupled without transmission or transmission to the fastening device 9 or to the crankshaft 4. To transmit the drive power, an input shaft 13 or a drive shaft may be provided.

The impact devices 1 described in more detail below by way of example are each held adjustably in a displacement and adjusting device 15 in order to adapt them to the position of the connecting rod journal 5 and the main bearing journal 6 and to the length of the crankshaft 4. The support 1 1 may be arranged to be displaceable, as indicated by the double arrows in Figure 1.

FIG. 1 shows two impact devices 1, but in principle any number of impact devices 1 may be provided, for example only a single impact device 1.

For the operation of the drive device 3, which preferably comprises an electric motor, a position 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 a transition radius 8 has been impact-hardened in a desired manner, the impact devices 1 can be moved to the transition radii 8 to be consolidated next.

FIG. 2 is a fragmentary perspective view of a further device for carrying out the method according to the invention, but without a beating device. The device of FIG. 2 is essentially identical to the device of FIG. 1, for which reason reference will be made below to the essential differences in detail.

Again, a drive device 3 is provided. Furthermore, a fastening device 9 is provided, which has a fastening 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 a drive shaft or an input shaft 13.

The crankshaft 4 of FIG. 2 has a configuration differing from the embodiment shown in FIG. 1, but basically also comprises connecting rod journal 5, main bearing journal 6 and crank webs 7. In FIG. 2 (as in FIG. 1), it is possible to turn away from the drive device 3 End of the crankshaft 4 may be provided a further fastening device 9, but this may also be omitted.

FIG. 3 shows, by way of example, a beating device 1 of FIG. 1 in greater detail. The invention can in principle be implemented with any impactor 1. However, the impact device 1 described below is particularly suitable. It has a main 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 two impact tools 16 in their support plane and at the support angle or impact angle α (see FIGS 6) to give a deflection unit 20 a corresponding freedom, which is advantageous for adaptation to the dimensional conditions of the crankshaft 4. At the front ends of the two impact tools 16 each have a ball is arranged as a striking head 21. An intermediate part 22 establishes the connection between a percussion piston 23 and the deflecting unit 20, which transmits the impact energy to the striking tools 16. The intermediate part 22 may optionally be omitted. To increase the effectiveness of the impact, a clamping prism 24 can be fastened by means of springs 25 with adjustable clamping bolts 26 with clamping nuts 27 on the side of the journal 5, 6 facing away from the main body 18. Here are also other constructive solutions possible.

By arranging a plurality of impactors 1 over the length of the crankshaft 4 to be machined, all centric and optionally eccentrically extending regions of the crankshaft 4 can be machined simultaneously if required.

According to the invention, the percussion piston 23 transmits a force impulse to the percussion tools 16 via the deflecting unit 20, whereafter the striking heads 21 of the percussion tools 16 introduce a striking force F _s into the transition radii 8 at an impact angle α. It is provided that the distance d (see. FIG. 4) between the deflection point U _{P of} the deflection unit 20 and the front end of the respective impact head 21 of the striking tools 16.

The term "F _s " and similar expressions in the present specification are to be construed only as placeholders / variables for any impact force deemed appropriate by the skilled person. If reference is made in the description to "the striking force F _s ", it can thus be in each case different or even identical impact forces.

In Figure 3, the technical solution for setting the distance d is shown only highly schematized. For example, a change device 30 with a magazine can be provided in order to exchange the at least one impact tool 16 and / or the impact head 21 and / or the deflection unit 20 and / or the at least one impact device 1 by the distance d between the deflection point Up of the deflection unit 20 and the front end of the impact head 21 of the at least one impact tool 16 to a different value. In FIG. 3, a change device 30 for exchanging impact tools 16 is indicated. For this purpose, the changing device 30 comprises a selection of striking tools 16 each having a different length. By replacing a striking tool 16, the distance d and thus the impact angle α can be adjusted.

It can also be provided that the length of the impact tools 16 is adjustable, preferably telescopic. A corresponding structure is shown in FIG. FIG. 4 shows a section of a beating device 1, which may be of essentially identical construction, as in the embodiment of FIG. 3.

FIG. 4 schematically shows two telescoping impact tools 16. Due to the adjustable length of the impact tools 16, the distance d between the deflection point U _{P of} the deflection unit 20 and the front end of the impact head 21 is adjustable. As a result, the impact angle α and optionally also the impact position can be indirectly influenced thereby.

It can also, as shown in Figure 1, be provided to use several impact devices 1. Preferably, the respective distance d between the deflection point U _P and the impact head 21 is then not identical, at least in the case of two impact devices 1. This makes it possible to use the impact devices 1 in each case for impact hardening of a transition radius 8 or a group of transition radii 8, wherein the impact tools 16 of the respective impact device 1 are each already set to the preferably provided impact angle α. A conversion of the beater 1 is therefore not necessary. Insofar as the crankshaft 4 only has transition radii 8 with two different advantageous impact angles α, it is therefore preferable to use two correspondingly preset impact devices 1.

It can, for. B. be provided that a first impact device 1 impact forces F _s under a first impact angle and a second impact device 1 impact forces F _s under a second impact angle α _{2 introduces} . Striking devices 1 can also be used in which the distance d or the impact angle α can be set in different ways. It can also be a conventional one

Beater be combined with a beating device 1 according to the invention. It can be provided that the impact angle α between the longitudinal axis L _s of the at least one striking tool 16 and a solder l _K w to the longitudinal axis C _K w of the crankshaft 4 5 ° to 80 °, preferably 10 ° to 70 °, more preferably 20 ° to 60 ° and more preferably 30 ° to 55 °, in particular 35 ° to 50 °. To clarify the relationships, magnifications are shown in FIGS. 5 and 6, which represent in highly schematic form a striking head 21 of a striking tool 16 and an exemplary transition radius 8 of a crankshaft 4. In this case, in the example of FIG. 5, oci is impact-bonded at a first impact angle aci and in FIG. 6 at a second impact angle a ₂ . By the appropriate adjustment of the impact angle α on the change in the distance d between the deflection point U _{P of} the deflecting unit 20 and the impact head 21 of the impact tool 16, the direction of the impact force F _s can pretend, whereby the area of maximum effectiveness of the striking hardening is specifically adjustable. It can also be provided to selectively reduce the impact force F _s or to change the direction of action if z. B. reduced cross-sections, holes or other geometric conditions require it.

Preferably, the impact angle α is selected according to the course of a maximum load MAXL MAX _{2 of} the transition radius 8, after which the profile of the maximum stress

MAXL MAX _{2 is determined} on the basis of simulations and / or calculations and / or test series of the respective crankshaft type.

In FIG. 6, the impact head 21 is positioned at the same position of the transition radius 8 as in FIG. 5. However, the distance d between the deflection point U _{P of} the deflection unit 20 and the impact head 21 is set such that the impact tool 16 is aligned at a different impact angle α As shown in Figure 5. This results in that the impact is introduced at an angle a ₂ in the transition radius 8, although the impact head 21 is basically attached to the same position as in Figure 5. The illustration in FIG. 6 deviates particularly strongly from the representation in FIG. 5 for the sake of clarity.

In principle, the positioning of the impact head 21 in the transition radius 8 can be changed, ie the impact head 21 could possibly also start at a deviating position along the circumference of the transition radius 8, wherein the impact angle α can be changed simultaneously. The impact head 21 may have a radius r _s whose size is 75% to 99% of the transition radius 8, preferably 85% to 98% of the transition radius 8 and particularly preferably 85% to 95% of the transition radius 8. Preferably, the radius r _{s of} the impact head 21 essentially corresponds to the transition radius 8.

In the figures 7 and 8 exemplary transition radii 8 between a main journal 6 and a crank arm 7 are shown in which the impact hardening is carried out at different angles α and in which the impact impressions 28 of a percussion head 21 of the percussion tool 16 along the annular to a main journal 6th overlap circumferential transition radius 8. In this case, the impact head 21 penetrates at least partially into the impact impression 28 of the preceding impact in a subsequent impact, as a result of which the "trace" shown in the figures results from impact impressions 28.

In FIGS. 7 and 8, the impact impressions 28 for the illustration are clearly visible on the circumference of the transition radius 8 offset from one another. In fact, the deviation is preferably small but nevertheless effective. The staggered course can be achieved by changing the impact angle, as shown in FIG. 6, and / or by changing the point of impact of the impact head 21. In the transition radius 8 of Figure 7, a smaller impact angle α was selected than at the transition radius 8 of Figure 8, ie the distance d between the deflection point U _{P of} the deflection unit 20 and the impact head 21 of the impact tool 16 was greater in the method of FIG Accordingly, the impact impressions 28 in the transition radius 8 shown in FIG. 8 run further up or closer to the crank arm 7 than is the case with the transition radius 8 of FIG.

It can also be provided that the impact angle α of a percussion tool 16 during the striking hardening of a transition radius 8 along the annular transition around the connecting rod journal 5 and / or main journal 6 respective transition radius 8 is changed. This is shown in FIG.

It can be provided that all transition radii 8 between the connecting rod journal 5 and the crank webs 7 with a first impact angle α and all transition radii 8 between the main bearing journal 6 and the crank webs 7 are α impact-solidified at a second impact angle. Alternatively it can be provided that at least two transition radii 8 are impact-bonded α between the connecting rod journal 5 and the crank webs 7 at a different impact angle and / or that at least two transition radii 8 are impact-bonded between the main journal 6 and the crank webs 7 at a different impact angle α and / or that at least one transition radius 8 between the connecting rod journal 5 and the crank webs 7 is under an Another impact angle α is impact-hardened than a transition radius 8 between the main bearing journal 6 and the crank webs 7.

Claims

P a n t a n s p r e c h e Device for impact hardening of transition radii (8) of a crankshaft (4), in particular of transition radii (8) between connecting rod journal (5) and crank webs (7) and / or transition radii (8) between the main bearing journal (6) and the crank webs (7) of the crankshaft (4), comprising at least one impactor (1) with a percussion piston (23), a deflection unit (20) and at least one impact tool (16), wherein the percussion piston (23) via the deflection unit (20) an impact on the at least one striking tool (16) transmits, wherein a striking head (21) of the at least one striking tool (16) at a striking angle (a) introduces a striking force (F _s ) into the at least one transition radius (8), d a d u r c h e c e n c i n e s that the device is arranged to adjust the distance (d) between a deflection point (U _P ) of the deflection unit (20) and the front end of the impact head (21) of the at least one striking tool (16). Device according to claim 1, d a d u r c h e c e n c i n e s that the length of the at least one striking tool (16) is adjustable, preferably telescopic. Apparatus according to claim 1 or 2, d a d u r c h e c e n c i n e s that a changing device (30) is provided with a magazine for exchanging the at least one impact tool (16) and / or the impact head (21) and / or the deflecting unit (20) and / or the impactor (1) to reduce the distance (i ) between the deflection point (U _P ) of the deflection unit (20) and the front end of the impact head (21) of the at least one impact tool (16) to a different value. Apparatus according to claim 1, 2 or 3, d a d u r c h e c e n c i n e s that two or more impact devices (1) are provided, wherein the distance between the deflection point (U _P ) of the deflection unit (20) and the front end of the at least one impact head (21) of a first impact device (1) is not identical to the distance between the deflection point (U _P) of the deflection unit (20) and the front end of at least one blow head (21) of a second percussion device (1). Device according to one of claims 1 to 4, characterized in that the at least one impact device (1) has two impact tools (16), the impact tools (16) being arranged on the deflection unit (20) such that each impact tool (16) is associated with a transition radius (8). Device according to one of claims 1 to 5, d a d u r c h e c e n c i n e s that the impact angle (a) between the longitudinal axis (L _s ) of the at least one impact tool (16) and a solder (l _K w) to the longitudinal axis (C _K w) of the crankshaft (4) 5 ° to 80 °, preferably 10 ° to 70 °, more preferably 20 ° to 60 ° and particularly preferably 30 ° to 55 °, in particular 35 ° to 50 °. Device according to one of claims 1 to 6, d a d u r c h e c e n c i n e s that the impact head (21) has a radius (r _s ) whose size is 75% to 99% of the transition radius (8), preferably 85% to 98% of the transition radius (8) and more preferably 85% to 95% of the transition radius (8) is. Method for impact hardening of transition radii (8) of a crankshaft (4), in particular of transition radii (8) between connecting rod journal (5) and crank webs (7) and / or transition radii (8) between main bearing journal (6) and the crank webs (7) of the crankshaft (4) with a device according to one of claims 1 to 7. Method according to claim 8, d a d u r c h e c e n c i n e s that the impact angle (a) according to the curve of a maximum load (MAX !, MAX ₂ ) of the transition radius (8) is selected, after which the curve of the maximum load (MAXL MAX ₂ ) on the basis of simulation and / or calculations and / or test series of the respective type of crankshaft is determined. Method according to claim 8 or 9, d a d u r c h e c e n c i n e s that All transition radii (8) between the connecting rod journal (5) and the crank webs (7) and / or all transition radii (8) between the main journals (6) and the crank webs (7) under the same impact angle (a) are impact-solidified. Method according to one of claims 8 or 9, d a d u r c h e c e n c i n e s that at least two transition radii (8) between the connecting rod journal (5) and the crank webs (7) under a different impact angle (a) are impact-strengthened and / or that at least two transition radii (8) between the main bearing pin (6) and the crank webs (7) un - At least one transition radius (8) between the connecting rod journal (5) and the crank webs (7) under a different impact angle (a) is impact-solidified than a transition radius (8) between the main journal ( 6) and the crank webs (7). Method according to one of claims 8 to 11, d a d u r c h e c e n c i n e s that during impact hardening of a ring-shaped around the connecting rod journal (5) and / or the main bearing journal (6) encircling transition radius (8) of the impact angle (a) is changed. Crankshaft (4), produced by a method according to one of claims 8 to 12.