DE102009018988A1 - Hardening a surface of a complex thin-walled component with varying cross-section by hardening critical surface area using an ultrasonic vibrator and a tool, comprises delivering high-frequency local mechanical impulse to the component - Google Patents

Abstract

The method for hardening a surface of a complex thin-walled component with varying cross-section by hardening critical surface area (7) using an ultrasonic vibrator (1) and a tool connected with the ultrasonic vibrator, comprises delivering high-frequency local mechanical impulse to the component for hardening using local deep-reaching compressive stresses, positioning the tool onto the surface to be processed, switching-on the ultrasonic vibrator, and guiding along the tool onto the component surface, where the tool has a contour adapted to the complex surface of the component. The method for hardening a surface of a complex thin-walled component with varying cross-section by hardening critical surface area (7) using an ultrasonic vibrator (1) and a tool connected with the ultrasonic vibrator, comprises delivering high-frequency local mechanical impulse to the component for hardening using local deep-reaching compressive stresses, positioning the tool onto the surface to be processed, switching-on the ultrasonic vibrator, and guiding along the tool onto the component surface, where the tool has a contour adapted to the complex surface of the component to be processed at its tool head and is guided along to the surface to be processed during the treatment, so that the adapted contour is congruent at anytime with the contour of the surface to be treated. The thread component (6) has an external thread and an internal thread. The high-frequency local mechanical impulse is produced using ultrasonic impact treatment, where the treatment frequency is 10-30 kHz and the treatment is carried out without a mechanical supporting tool. The component and/or the tool are automatically led. The tool and the component are rotated relative to each other and are linearly movable to each other. The tool is pressed on the component with a defined pressing force. The component is heated for treatment. The treatment of the surface repeatedly consecutively takes place and/or with several tools. An independent claim is included for a device for hardening a surface of a thin-walled component with complex varying cross-section.

Description

introduction

The The invention relates to a method and a device for surface hardening Complex thin-walled components with varying cross section through Solidification of the critical surface areas, wherein for consolidation by means of local deep-reaching compressive stresses high-frequency local mechanical impulses are emitted to the component. In particular, the invention relates to surface hardening highly stressed thin-walled threaded components.

State of the art

It It is known that the load capacity of components by increasing the surface strength can be improved. Especially this improvement relates to the wear resistance, the tendency to crack, and thus the life of such components, resulting in higher Operational reliability and lower costs.

to Increasing the surface strength are from the Prior art various methods known. Come here In particular, mechanical methods are used.

To a method, the surface to be solidified by Shot blasting. Staggered by the statistically distributed Balls made of steel, for example, become near-surface Areas plastically deformed and compacted. A disadvantage of one However, such a solution is insufficient in conducting as well as the limited adjustable impact speed the shot peening, so that at work result with tolerances both in terms of uniformity as well the local limitation of the treatment must be calculated. Especially for small and / or thin-walled components Therefore, this technique is not applicable. Also the achievable surface roughness meets only limited requirements. After all become geometric through the statistically distributed impact of the spheres destroys defined surface structures.

One Another method provides for surface hardening by means of Rolling before. Such solutions are geometry-related but not for components such as threaded nuts or hollow shafts used. Further, due to the need the pressing against the surface to be treated a Hinterstützung indispensable especially for thin-walled components.

To another method is needed for solidification Energy by means of a high-frequency oscillating tool (sonotrode) brought into the workpiece surface. Come to this preferably ultrasonic vibrator used. By use a geometrically clearly definable and alignable tool can achieve correspondingly narrower tolerated results.

In the publication DE 102 43 415 A1 discloses a method for surface hardening, by means of a contact shoe, which is attached to a sonotrode and oscillates in the axial direction, at least local and macroscopic plastic deformations are achieved on the component, which lead to the desired Oberflächenverfestigungen. In particular, in thin-walled components, however, macroscopic plastic deformations are undesirable because otherwise the dimensional accuracy of the components would be too much affected.

In the publication US 2002 0037219 A1 there is disclosed an ultrasonic excited device especially for treating turbine blades and the like. The possibly more than one sonotrode hammer from one or two sides of the workpiece, the distribution of pulses statistically distributed and therefore unsuitable for components with a defined, especially three-dimensional surface structure or for sharp-edged components. In addition, the sonotrodes at their ends only rounded shapes that would lead to the immediate destruction of the threads on contact, for example, a thread-like component. As with other statistically operating methods, the achievable surface roughness satisfies only limited requirements.

In the DE 10 2004 058 146 A1 discloses a method including device for surface hardening of components by "Ultrasonic Impact Treatment" (UIT). Again, a sonotrodenartiges tool is used. To improve the effect of the tool on the workpiece, the tool axis is aligned obliquely to the component surface to be solidified. This results in advantages in the targeted and preferred-oriented generation of solidification states even with thin-walled components, since the high-frequency mechanical processing of the components are expected even at low component masses no significant component shifts or macroscopic deformations. According to the document, although the tool disclosed therein is also suitable for micro-profiling of components, such a micro-profiling is a geometry distributed randomly on the component surface and not to be compared with a geometrically precisely defined geometry that is tolerated over relatively large areas such as a thread. A tool for surface hardening of threaded components is in the relevant Reference, however, not disclosed.

description

Of the Invention is based on the object, a method and an apparatus to provide, with or with the surface hardening complex thin-walled components with varying cross section and especially thin-walled threaded components allows becomes. Both internal and external threads are to be processed can be. The treatment should be support-free done and surfaces with a very low surface roughness produce. The geometries arranged on the surface may not be changed in their form. It should be solidified in addition to two- and three-dimensional geometries can. The invention is also an economical parallel treatment several similar neighboring geometries with only one tool enable.

The Invention discloses a surface consolidation process complex thin-walled components with varying cross section by solidification of the critical surface areas. In doing so, local deepening compressive stresses occur for solidification used by means of high-frequency local mechanical impulses be delivered to the component.

The inventive method is particular suitable for surface hardening of threaded components. Threaded components are characterized by a regular, arranged at its inner or outer periphery, closely tolerated geometry, where the cross-section of the component along its thread axis is not constant, but accordingly the thread shape varies. During surface hardening Of threaded components, it is therefore particularly important to have a tool which does not use the well-defined geometries or only plastically deformed to the slightest extent, so that too After treatment, the geometric properties of the threaded components and especially the threads are completely intact.

to Treatment a tool is used with a tool head which one to the complex surface to be processed having the component adapted contour. During the treatment this is attached to and from an ultrasonic transducer in high-frequency oscillations offset tool with the tool head such guided along the surface to be machined, that the adjusted contour at any time with the contour of the treated Surface is congruent. Congruent means that the Contours of the tool head essentially as an inverted image formed the contours of the region to be solidified of the component are, and therefore exactly on or on the component surface must be positioned. In this way it is ensured that also complex, non-level surfaces in the desired Way are workable without damaging the Surface geometries are done. For a continuous Machining must be tool and component relative to each other be moved, which will be discussed in detail later.

to Treatment must first of all the tool to be edited Surface to be positioned.

If has not happened yet, at the latest now the ultrasonic transducer be turned on, which transmits the vibration movements to the tool.

After all must the tool or the tool head on the component surface be guided along. It is particularly preferred that this entrainment takes place continuously. In the case of a thread-like designed Component surface, it is preferred that at the same time a Rotation of the component relative to the tool and a linear movement is performed. Depending on the application, it may be advantageous be the tool or component or both components at the same time execute one or even all necessary movement types. It is particularly preferred if the tool is the linear movement and the component performs the rotational movement.

By Application of the method according to the invention is Ensured that the treated surface is a very has low surface roughness. Such a small one Surface roughness is by means of the stand not reachable by the art, especially not with economic parallel treatment several adjacent structures by means of a single tool.

The inventive method is particularly good for threaded components with an external thread suitable.

Further however, the process of the invention may as well used for threaded components with an internal thread. It is irrelevant whether the thread only over Parts or over the entire length of the threaded component extends. In addition, the inventive method also in areas where there is no thread used become.

In order to generate the high-frequency local mechanical impulses, according to a preferred embodiment, an ultrasonic vibrator for treatment (Ultrasonic Impact Treatment, UIT) is used puts.

Especially This ultrasonic vibrator is preferably in a frequency range operated from 10 kHz to 30 kHz. It is possible that the Amplitude of oscillation constant throughout the treatment held or varied as needed.

To a particularly preferred embodiment of the invention The procedure will be the treatment without a mechanical support carried out. That means that even with very thin-walled Components having wall thicknesses in the range of 0.1-2 mm, a treatment is possible in which to extra Aids on the back of the treated Surface must be arranged, waived can be. This is particularly advantageous if, for example, long tubular components must be treated outside, because the inside of such components difficult to access is, so for a correspondingly effective support a high effort would have to be operated.

To In another preferred embodiment, the component and / or the tool automatically guided. An automated Leadership offers itself in principle, since the mostly Required tolerances with manual guides difficult or impossible are unreachable. For exterior or interior treatment easily manageable components, it is sufficient if the component is automated. For more complex designed Components or those which are already installed, in particular an automated tool guide advantageous. It is but also a combination of manual and automated component or tool guide conceivable, the coarse positioning done manually, the subsequent positioning during the Treatment is automated, however.

To Another preferred embodiment the tool and the component are rotated relative to each other. This is particularly appropriate in such cases, in which are rotationally symmetrical components, which at Threaded components is basically the case. It is possible that the tool is stationary and the component along the tool rotates, or that the component is stationary and the tool to the component rotates. In certain cases it can be beneficial be when both the component and the tool relative to each other (same and opposite directions) can rotate.

To Another preferred embodiment the tool and the component are moved linearly relative to each other. This means, for example, that the tool is parallel to the axis of rotation of the rotationally symmetrical component can move. A Such movement is, for example, by threading means a lathe ago known. However, it can also be beneficial that the component moves linearly along the tool, for example then if the tool is due to its size or forum less easily than the component is manageable.

To another embodiment may be tool and / or component are guided on any tracks. For this purpose, robotic guidance devices are particularly preferred for use.

After all Combinations of the above variants are also conceivable both in terms of relative rotation as also the relative linear movement, as well as with regard to combinations from rotation and linear movement as well as any web guide.

To another preferred embodiment of the invention Method is provided that the tool with a defined contact force is pressed onto the component. The contact force can, for example pneumatic, hydraulic, electromechanical, or over be provided a simple spring

To Yet another embodiment is provided that the component is heated for treatment. By means of this Heating, for example, electric, in particular by heating coil or a voltage applied between the tool and the component, Electromagnetically, in particular by induction or by radiant heat can be generated, the treatment effect may be additional be increased.

To another embodiment provides that the Treatment of the surface several times in succession and / or done with several tools. It can be of treatment for treatment or from tool to tool different treatment parameters (Contact pressure, amplitude, feed rate, feed direction, Degree of heating, treatment frequency, tool geometry) be beneficial.

The The invention further discloses a surface hardening apparatus thin-walled components with a complex varying Cross-section. It is provided that the device is a component for providing high-frequency mechanical impulses, as well as a Component for transmission of high-frequency mechanical Impulse on the component to be treated (sonotrode) includes.

The Surface hardening results from local deepening Compressive stresses. The invention is particularly intended to that the component to be treated is a thin-walled threaded component is. In order to enable processing of such components, is inventively provided that the component for transmission of high-frequency mechanical impulses a tool head whose contour to be machined complex surface of the component is adjusted. With others Words only allows the shape of the tool head the inventively desired machinability. The proposed shapes are particularly in the context the figure descriptions explained in more detail.

To In a preferred embodiment, the component is for Providing high-frequency mechanical impulses an ultrasonic transducer. Particularly preferably, the ultrasonic vibrator operates in a range from 10 kHz to 30 kHz. The vibrations can be, for example generated by piezoceramic or electromagnetic components become. The oscillation direction is substantially opposite to Component surface aligned.

Especially it is preferably provided that the component for transmission the high-frequency mechanical impulses on the component to be treated at their intended for mechanical contact of the component End, which is designed as a tool head, has a contour, which of the inverted contour of at least a part of the to be treated Component corresponds. For example, is the surface to be treated provided as an external thread, so must the contour of the tool head as an inverted external thread in the to be consolidated Be executed area. The same thing applies in the case of an internal thread.

With In other words, the tool just reflects the inverted contour the surface of the component again. It can be provided be that the tool contour aware of locally from the component contour deviates to at these points a concentration of force or a Force reduction in the transmission of impulses to the Achieve component surface.

Further This means that the location of the tool relative to the component must be precisely controllable at any time, as in a faulty positioning between workpiece and component destruction the geometries arranged on the surface of the component such as the threads would be the result.

To In one embodiment, the tool is designed that its geometry is just the smallest repetitive unit corresponds to the component surface geometry. For the case of an external or internal thread is therefore the Tool geometry so that they, for example, just about the width of a thread extends.

To In another embodiment, the tool is configured to that its geometry is a multiple of the corresponding smallest repetitive unit of component surface geometry equivalent. In the case of an external or internal thread Accordingly, the tool geometry is such that it is, for example just over two, three, or over another Number of threads extends.

To Another embodiment is the contour of the tool formed two-dimensionally. That means the contour of the tool corresponds to the inverted contour of a two-dimensional section, which passes through the axis of rotation of the component.

To Another embodiment is the contour of the tool three-dimensional, so designed as a relief. It means that the contour of the tool a section of the inverted three-dimensional Surface geometry of the component corresponds. It must the three-dimensional surface geometry of the component regular and repetitive sections which, for example, gradually through the tool be processed. In the case of a rotationally symmetric If necessary, this processing can also be carried out continuously. In the sense of the above example of an (external) thread would correspond the tool geometry an inverted segment cutout of the component surface. By rotating the component and an axially-parallel linear movement of the Tool can then also surface treatment by means of made a relief-like designed tool geometry.

It is preferred that the tool and the component relative to each other are rotatable and / or relatively linearly movable. Especially preferred is it that both types of movement combined feasible are, especially when machining threaded surfaces is advantageous.

According to a particularly preferred embodiment, it is provided that the movements of the tool and / or component can be automated, for which purpose, for example, robot-supported guide devices can be used. The method according to the invention described allows a surface hardening of complex thin-walled components with varying cross section and in particular a treatment of highly stressed thin wall-mounted threaded components by solidification of the critical surface areas by means of high-frequency local mechanical impulses. With the tool described in the context of the device according to the invention, adapted to the contour of the component surface also machining of threaded components in an economical and effective manner is also achievable. By means of the tool according to the invention, due to the various embodiments covered within the scope of the invention, two-dimensional, but also three-dimensional surface geometries of both internal and external threads can be machined. The surface roughness achievable by means of the method according to the invention and the device according to the invention are significantly lower in comparison with the method or devices carried out according to the prior art, so that optionally post-processing steps can be dispensed with.

By Application of the method or the device according to the invention is the wear resistance, the tendency to crack, and thus the life of thin-walled Threaded components improved, resulting in higher operational safety and lower costs.

The Invention is limited in its execution not to the preferred embodiments given above. Rather, a number of variants is conceivable, which of the illustrated Solution even with fundamentally different kind Designs makes use.

figure description

The 1 shows a preferred embodiment of the device according to the invention as a side view.

The 2A and 2 B show modifications of the tool according to the invention as side views.

In the 1 a preferred embodiment of the device according to the invention is shown. The inventively provided component for providing high-frequency mechanical impulses is as ultrasonic oscillator 1 formed, its essential direction of vibration 2 represented by the double arrow. With the ultrasonic transducer 1 the component according to the invention which is likewise to be provided for transmitting the high-frequency mechanical impulses to the component to be treated is connected as a sonotrode 4 is trained. The ultrasonic transducer 1 and thus also the sonotrode 4 are along different directions of movement 3 relative to each other movable. It is therefore irrelevant whether the sonotrode 4 , which represents the tool, or the component, which as a thin-walled threaded component 6 is formed, move, if a corresponding relative movement is possible.

At the top of the sonotrode 4 is a sonotrodes head 5 arranged (dotted area), which direct mechanical contact with the component 6 manufactures. Due to the high-frequency mechanical impulses acting on the sonotrode head 5 by means of the ultrasonic vibrator 1 be transferred, a surface hardening of the threaded component 6 achieved. Because of the high frequency is also the low mass of the threaded component 6 unproblematic.

The already processed and thus solidified surface area 7 is through the thicker drawn contour line of the threaded component 6 symbolizes. In the example shown, the processing was at the left in the picture lying end of the threaded component 6 began. The relative movement takes place in a parallel direction of movement 3A to the axis of rotation 8th of the threaded component 6 , During machining, the threaded component becomes 6 around the axis of rotation 8th rotated, so that at the same time relative movement in the direction of movement 3A a continuous surface hardening of the peripheral region can be achieved.

The 2A shows a first modification of the tool according to the invention, in particular the sonotrode 4 , This includes a plurality of juxtaposed sonotrodes 5 , By means of such a tool is therefore a high-precision parallel processing, for example, several courses of the external thread of a thin-walled threaded component possible.

The 2 B shows a further modification of a sonotrode 4 , according to the shape of each sonotrode heads 5 not round, but pointed ending and asymmetrical. Such a Sonotrodenkopfform is therefore suitable, for example, for the parallel processing of multiple courses of Sägegewindeoberflächen but also other thread forms such. B. trapezoidal thread, can be edited accordingly.

1

Ultrasonic vibrator Component for providing high-frequency mechanical impulses

2

vibration direction

3

directions of movement

3A

parallel movement direction

4

component for the transmission of high-frequency mechanical impulses, Sonotrode, tool

5

sonotrode, tool head

6

thin-walled Threaded component, component with varying cross section

7

solidified surface area

8th

axis of rotation

9

reason

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10243415 A1 [0007]
• US 20020037219 A1 [0008]
• - DE 102004058146 A1 [0009]

Claims (19)

Process for the surface hardening of complex thin-walled components ( 6 ) with varying cross-section by solidification of the critical surface areas by means of an ultrasonic vibrator ( 1 ) and an associated tool ( 4 ), wherein for solidification by means of local deep-reaching compressive stresses high-frequency local mechanical impulses are delivered to the component, characterized in that the tool ( 4 ) on his tool head ( 5 ) to the to be machined complex surface of the component ( 6 ) and is guided along the surface to be processed during the treatment such that the adapted contour is always congruent with the contour of the surface to be treated, comprising the following steps: positioning the tool on the surface to be machined; - switching on the ultrasonic vibrator; - Passing the tool on the component surface. Method according to claim 1, wherein the threaded component ( 6 ) has an external thread. Method according to claim 1, wherein the threaded component ( 6 ) has an internal thread. Method according to one of the preceding claims, where the high-frequency mechanical pulses using ultrasound Impact Treatment (UIT) are generated. The method of claim 4, wherein the treatment frequencies in a range of 10 kHz to 30 kHz. Method according to one of the preceding claims, the treatment being without mechanical support is carried out. Method according to one of the preceding claims, wherein the component ( 6 ) and / or the tool ( 4 ) is automated. Method according to one of the preceding claims, in which the tool ( 4 ) and the component ( 6 ) are rotated relative to each other. Method according to one of the preceding claims, in which the tool ( 4 ) and the component ( 6 ) are moved linearly relative to each other. Method according to one of the preceding claims, wherein the tool 4 with a defined contact pressure on the component ( 6 ) is pressed. Method according to one of the preceding claims, in which the component ( 4 ) is heated for treatment. Method according to one of the preceding claims, in which the treatment of the surface is carried out several times in succession and / or with a plurality of tools ( 4 ) he follows. Device for surface hardening thin-walled components ( 6 ) having a complex varying cross-section, comprising - a component for providing high-frequency mechanical impulses ( 1 ); A component for transmitting the high-frequency mechanical pulses ( 4 ) on the component to be treated ( 6 ); wherein solidification of the critical surface areas by means of local deep-reaching compressive stresses by delivery of the high-frequency local mechanical impulses to the component ( 6 ) is achievable, characterized in that the component for transmitting the high-frequency mechanical pulses ( 4 ) a tool head ( 5 ) with the complex surface of the component ( 6 ) has adapted contour. Apparatus according to claim 13, wherein the component for providing high-frequency mechanical pulses ( 1 ) is an ultrasonic transducer. Device according to one of claims 13 or 14, wherein the component for transmitting the high-frequency mechanical pulses ( 4 ) on the component to be treated ( 6 ) at its for mechanical contact of the component ( 6 ) as a tool head ( 5 ) has a contour which corresponds to the inverted contour of at least part of the component to be treated ( 6 ) corresponds. Apparatus according to claim 15, wherein the contour is two-dimensional is trained. Apparatus according to claim 15, wherein the contour is three-dimensional is trained. Device according to one of claims 13 to 17, wherein the tool ( 4 ) and the component ( 6 ) are rotatable relative to each other and / or linearly movable relative to each other. Device according to one of claims 13 to 18, wherein the movements of tools ( 4 ) and / or component ( 6 ) can be automated.