DE102022210900A1 - Component for a mechanical device - Google Patents

Abstract

The disclosure describes a component (100) for a mechanical device, wherein the component (100) consists at least partially of steel and has one or more circular recesses (102-105) for receiving a screw. In addition, the steel for a respective circular recess (102-105) is hardened in a first region (106-109) immediately surrounding the respective circular recess and is unhardened in a second region (110) immediately surrounding the first region.

Description

This disclosure relates to a component for a mechanical device, a manufacturing device for manufacturing this component and a method for manufacturing this component.

Large machine components are often connected to one another using screw connections. This requires holes, also referred to as recesses, in the components. If the base material is steel and the machine is exposed to environmental influences such as rain and temperature fluctuations or dynamic loads, corrosion can form in the holes and be the starting point for rapidly growing cracks in the material. The consequences of the cracks expanding are almost always catastrophic, as the integrity of the machine is no longer guaranteed.

To prevent the loss of machine integrity, machines must be continuously monitored, usually manually, for corrosion and rapidly growing cracks. Alternatively, it is possible to coat the holes from the inside to prevent corrosion. However, especially in large structures, the tolerances of the individual components result in situations in which a screw used touches the wall of the hole and can damage the coating. This means that additional monitoring of the machine must be carried out with this solution. However, such monitoring always involves a great deal of effort and usually means shutting down the machine for a certain period of time. Both the monitoring itself and the shutdown of the machine lead to high costs.

The aim of this disclosure is therefore to provide an improved solution for protecting the holes against corrosion.

This object is achieved by the component for a mechanical device according to claim 1, the manufacturing device for producing this component according to claim 8 and the method for producing this component according to claim 15. Preferred embodiments are described in the dependent claims, respectively.

In the following, the component for a mechanical device according to this disclosure is described in detail.

The component for a mechanical device consists at least partially of steel and has one or more circular recesses, in particular for receiving a screw. Furthermore, for each circular recess, the steel is hardened in a first region immediately surrounding the respective circular recess and the steel in a second region immediately surrounding the first region is unhardened.

The component is based on the surprising discovery that steel hardened around recesses is suitable for the production of resistant screw connections. Hardening is already known from the production of large rolling bearings. This hardening takes place in the area of the raceways, which are subjected to constant dynamic loads due to contact with the rolling elements. A softer base material (ring steel) is hardened a few mm from the surface. However, the application of this process to recesses for screw connections has not been obvious until now, because it is known that in the event of continuous, dynamic loads on these raceways, damage (rolling contact fatigue) occurs in the hardened area below the surface. The damage is cracks that form at defects in the material structure and subsequently migrate through the material. Until now, it has been assumed that analogous hardening of drill holes is not useful because this damage would extend into the base material and corrosion and rapidly growing cracks are to be feared here too. However, investigations into these damages have now shown that the damage progresses in the hardened area of the material but does not spread to the unhardened area. This means that the hardening limits the cracks to an area close to the surface of the borehole, which leads to improved protection of the boreholes against corrosion and against rapidly growing cracks.

Preferred embodiments of the component are now described below.

First, the term steel should be discussed here. For the purposes of this disclosure, this is understood to mean a material whose mass fraction of iron is greater than that of any other element, whose carbon content is generally less than 2% and which contains other elements (see also the definition of steel in EN 10020).

As already described above with reference to the rolling bearings, induction hardening is particularly suitable for hardening the steel around the recesses. Furthermore, the circular recesses are usually drilled holes. The recesses can also be made by grinding ing, eroding or cutting (e.g. with laser).

In some embodiments, the circular recess is a blind hole. In other embodiments, the component alternatively or additionally comprises at least one through hole. In some of these or other embodiments, the circular recess alternatively or additionally has a thread. Some embodiments of the component alternatively or additionally consist entirely of steel.

In one embodiment of the component, a surface hardness of the hardened steel in the first region is additionally or alternatively greater than 600 HRV and/or a surface hardness of the unhardened steel in the second region is additionally or alternatively less than 350 HRV. The unit HRV here refers to the scale V of the Rockwell hardness test for surfaces.

In another embodiment, the hardened steel in the first region alternatively or additionally consists of a material structure that has a martensite content that is greater than 50%. Alternatively or additionally, in some other embodiments, the unhardened steel in the second region consists of a material structure that is a mixed structure. In a variant of this embodiment, the mixed structure is bainitic and/or martensitic-bainitic.

In some embodiments, the hardened steel in the first region alternatively or additionally has a thickness of 0.5 to 5 mm. This corresponds to a thickness that can be produced by means of inductive hardening.

In another embodiment, the component is alternatively or additionally a ring element for a rolling bearing. The component can be either the outer or the inner ring of a rolling bearing. Especially with rolling bearings, corrosion protection of the recesses is advantageous due to the intensive stress.

Alternatively or additionally, in some variants of this embodiment, the component has a guide element for guiding a rolling element on an inner side of the ring element and/or on an outer side of the ring element. The outer side is understood to be a side of the component facing away from the axis of symmetry of the ring. Analogously, the term inner side is understood to be a side of the component facing the axis of symmetry.

In a further variant of the embodiment of the component described above, alternatively or additionally, the one or more circular recesses are arranged in the ring element in such a way that a longitudinal axis of the circular recess runs parallel to the axis of symmetry of the ring element. The axis of symmetry here is usually the axis of rotational symmetry that runs through a central hole in the ring element.

If the component is a guide element for guiding a rolling element, it is particularly advantageous to use it in a wind turbine. Such a wind turbine comprises a rolling bearing with a guide element for guiding a rolling element according to one of the embodiments described above. In particular, the rolling bearing is a large rolling bearing, a rotor bearing, a gearbox bearing, a generator bearing

• - eine Sonde mit einem Sondenkopf und einer am Sondenkopf angeordneten Spule, wobei die Sonde ausgebildet ist, in die kreisrunde Ausnehmung eingeführt zu werden, und
• - eine Verfahreinheit, die ausgebildet ist, den Sondenkopf entlang einer Längsachse der Sonde zu verfahren.

Die Fertigungsvorrichtung hat die gleichen Vorteile, wie das zu fertigende Bauelement.A manufacturing device for manufacturing the described component is now presented below. This manufacturing device comprises a processing tool, in particular a first processing tool, for inductively hardening the steel in the first area around a circular recess. For this purpose, the first processing tool has the following components.

• - a probe with a probe head and a coil arranged on the probe head, wherein the probe is designed to be inserted into the circular recess, and
• - a movement unit designed to move the probe head along a longitudinal axis of the probe.

The manufacturing device has the same advantages as the component to be manufactured.

In some embodiments, the manufacturing apparatus further comprises a power supply unit electrically connected to the coil and configured to provide an alternating current.

In other embodiments, the manufacturing device additionally or alternatively comprises a coil arrangement with a plurality of coils, wherein the plurality of coils are arranged symmetrically, in particular point-symmetrically, around a longitudinal axis of the probe. The symmetry can also be a rotational symmetry in the broader sense, wherein the coils are returned to a position that is congruent with the starting position by means of a rotation through a fixed angle of rotation between 0° and 360°. This is particularly advantageous in order to achieve uniform hardening of the steel in a recess.

In a preferred embodiment, the device additionally comprises a second processing tool which is designed to carry out a further manufacturing step for producing the component.

Alternatively, a device with two processing tools can also be described in simplified form as follows: Manufacturing device for manufacturing a component, comprising a first processing tool and a second processing tool, wherein the first processing tool is designed to harden the steel by means of inductive hardening in the first area around a drill hole, and the second processing tool is designed to carry out a further manufacturing step for manufacturing the component. This device is independent of the precise design of the processing tool for inductive hardening.

In a variant of the embodiment described above, the first machining tool and the second machining tool are designed to carry out the hardening of the steel and the further manufacturing step simultaneously.

In another variant, the device alternatively or additionally has a common coolant circuit for the first machining tool and the second machining tool.

In yet another variant, the manufacturing device alternatively or additionally comprises a common displacement element with which the first processing tool and the second processing tool are mechanically connected and which is designed to move the first processing tool and the second processing tool together.

In a further variant, the second machining tool comprises a drill that is designed to produce a circular recess. Alternatively or additionally, the second machining tool comprises a hardening tool that is designed to harden steel of a guide element for guiding a rolling element by means of induction.

In yet another embodiment, the first machining tool alternatively or additionally comprises one or more cooling liquid outlets arranged on the probe such that a cooling liquid film is formed above and/or below the coil so that sound emission caused by inductive hardening is reduced.

• - Herstellen einer kreisrunden Ausnehmung in einem Bauelement aus ungehärtetem Stahl für eine mechanische Vorrichtung, und
• - Induktives Härten des Stahls in einem ersten Bereich, der die kreisrunde Ausnehmung unmittelbar umgibt.

A method for producing a component as described above is now described below. The method comprises the following steps:

• - producing a circular recess in a component made of unhardened steel for a mechanical device, and
• - Inductive hardening of the steel in a first area immediately surrounding the circular recess.

In a preferred embodiment of this method, the production of a first circular recess and the hardening of a second circular recess, which is different from the first, are carried out simultaneously. This method is particularly time-efficient.

• - Bereitstellen eines Wechselstroms durch eine Spule in einem Sondenkopf einer Sonde,
• - Positionierung des Sondenkopfes an einem ersten Ende eines Bohrlochs, und
• - Verfahren des Sondenkopfes entlang einer Längsachse des Bohrlochs von vom ersten Ende des Bohrlochs zu einem zweiten, vom ersten Ende verschiedenen Ende des Bohrlochs.

In a further embodiment, the inductive hardening of the steel alternatively or additionally comprises the following steps:

• - Providing an alternating current through a coil in a probe head of a probe,
• - positioning the probe head at a first end of a borehole, and
• - Moving the probe head along a longitudinal axis of the borehole from the first end of the borehole to a second end of the borehole different from the first end.

In one version of this embodiment, the probe head is moved according to a given speed. In another version, an alternating current is provided with a given alternating current intensity.

• 1a zeigt ein Bauelement gemäß der Idee dieser Offenbarung mit vier Ausnehmungen;
• 1b zeigt einen Querschnitt des in 1a gezeigten Bauelementes;
• 2a zeigt eine Fertigungsvorrichtung zur Fertigung des in 1a gezeigten Bauelementes;
• 2b zeigt eine Spulenanordnung der in 2a gezeigten Fertigungsvorrichtung;
• 3 zeigt eine zweite Fertigungsvorrichtung zur Herstellung des in 1a gezeigten Bauelementes; und
• 4 zeigt ein Verfahren zur Herstellung eines Bauelementes gemäß der Idee dieser Offenbarung.

In the following, embodiments are described using the attached figures. First, an overview of the figures is given. What is shown in the figures is then discussed in detail.

• 1a shows a component according to the idea of this disclosure with four recesses;
• 1b shows a cross section of the 1a shown component;
• 2a shows a manufacturing device for the production of the 1a shown component;
• 2 B shows a coil arrangement of the 2a shown manufacturing device;
• 3 shows a second manufacturing device for producing the 1a shown component; and
• 4 shows a method for producing a component according to the idea of this disclosure.

In the following, the elements shown in the figures are described in detail. First, reference is made to the 1a and 1b shown component is discussed.

1a shows a component 100 according to the idea of this disclosure with four recesses 102-105. 1b shows a cross section of the 1a shown component 100. The 1b The cross section shown corresponds to the cross section along the 1a drawn plane E.

The component 100 is a component for a mechanical device, specifically in this example an inner ring of a rolling bearing for a wind turbine. In this exemplary embodiment, the component 100 consists entirely of steel. In other embodiments, however, the component can also comprise other materials.

The component comprises two guide elements 120 and 121 for guiding a rolling element on an inner side S of the component. The guide elements 120 and 121 have a hardened surface, as shown in 1b is indicated. However, this will not be discussed further below. Instead, we will focus on the circular recesses 102-105, which are also visible.

The component 100 comprises four circular recesses 102-105, here drill holes, for receiving a screw. The circular recesses 102-105 are through holes through which screws can be passed. In the 1a and 1b In the example shown, the recesses do not have a thread. In other embodiments, however, the recesses may also include a thread. The circular recesses are arranged in the component 100 such that a longitudinal axis L of each of the circular recesses runs parallel to the axis of symmetry A of the component.

Furthermore, the steel around a respective circular recess 102-105 is hardened in a first region 106-109 immediately surrounding the respective circular recess and unhardened in a second region 110 immediately surrounding the first region 106-109. The hardening of the steel to produce the component in the first region was carried out by inductive hardening. This ensures that in the first region in this example the hardened steel has a surface hardness of more than 600 HRV, whereas the surface hardness in the second region is less than 350 HRV. Due to the inductive hardening, the material structure in the first region has a martensite content of greater than 50%. In contrast, the unhardened steel in the second region is a mixed structure. Furthermore, the first region around the recesses has a thickness D of 5 mm, the thickness here being measured radially from a longitudinal axis L of the respective recess.

In the following, manufacturing devices for producing the component 100 are described using the 2a and 2 B and the 3 described.

2a shows a manufacturing device 200 for manufacturing the 1a shown component 100.

The device 200 comprises a processing tool for inductively hardening the steel in the first region around a circular recess. The processing tool has a probe 202 with a probe head 204 and a plurality of coils arranged on the probe head 204. In this case, the probe is elongated and rotationally symmetrical, in particular cylindrical, in order to be able to be inserted into a circular recess. The device 200 also comprises a displacement unit 206 which is designed to move the probe head 204 along a longitudinal axis B of the probe. The direction of travel is also indicated by a double arrow 208. In addition, the device 200 comprises a coolant outlet arrangement which comprises a first coolant outlet 210A and a second coolant outlet 210B. Both coolant outlets are arranged on the probe 202 in such a way that a coolant film is formed above and below the probe head 204 with the coil, so that sound emissions caused by inductive hardening are reduced.

In the following, the arrangement of the plurality of coils with reference to 2 B To be received.

2 B shows a coil arrangement 240 of the 2a device shown. 2 B shows a cross section through the coil head 204.

The coil arrangement 240 comprises eight coils 241-248. These coils are arranged symmetrically around the longitudinal axis B of the probe 202. This is particularly advantageous in order to achieve uniform hardening of the steel around a circular recess.

The device 200 can be used to harden the steel around a recess. In many cases, however, it is more economically viable to carry out the inductive hardening of the steel at the same time as another production step. A device which is trained for this purpose, is described below with reference to 3 described.

3 shows a second manufacturing device 300 for producing the 1a shown component 100.

The device 300 schematically comprises the machining tool from 2a as the first processing tool 200. In addition, the device 300 comprises a second processing tool 304, which is designed to carry out a further manufacturing step for manufacturing the component. The second processing tool 304 is the 3 The example shown is a steel drill that is designed to produce a circular recess. In other embodiments, the second machining tool can also be designed, for example, to harden steel of a guide element for guiding a rolling element by means of induction. In particular, the 3 However, the machining tools shown are designed to harden the steel and drill the steel simultaneously.

The manufacturing device 300 further comprises a common displacement element 310 with which the first machining tool 200 and the second machining tool 304 are mechanically connected and which is designed to move the first machining tool 200 and the second machining tool 304 together. In the 3 In the example shown, the movement element 310 is designed to move the two processing tools in a circle, as indicated by the double arrow 312. For example, both processing tools can be moved around a ring element. In addition, both processing tools are also designed to be moved around their respective longitudinal axes. This is indicated by the arrows 306 and 308.

In addition to a common movement element 310, the device 300 also has a common coolant circuit 320. This coolant circuit 320 comprises a collecting container 322 for coolant and a coolant pump 326 as well as a first connecting line 324 from the collecting container 322 to the coolant pump 326. The coolant circuit also comprises a second connecting line 328 and a third connecting line 330 through which the coolant is pumped from the coolant pump 326 to the first machining tool 200 or to the second machining tool 304.

Finally, with regard to 4 a process for producing the 1a and 1b shown component 100 will be discussed.

4 shows a method 400 for producing a component 100 according to the idea of this disclosure.

The method comprises the following steps. In a first step 402, a circular recess is produced in a component made of unhardened steel for a mechanical device. In a second step 404, the steel is inductively hardened in a first region that immediately surrounds the circular recess. In a particularly preferred procedure, the production 402 of a first circular recess and the hardening 404 of a second circular recess that is different from the first are carried out simultaneously.

In summary, the disclosure describes a component (100) for a mechanical device, wherein the component (100) consists at least partially of steel and has one or more circular recesses (102-105) for receiving a screw. In addition, the steel for a respective circular recess (102-105) is hardened in a first region (106-109) immediately surrounding the respective circular recess and is unhardened in a second region (110) immediately surrounding the first region.

Claims (16)

Component (100) for a mechanical device, wherein the component (100) consists at least partially of steel and has one or more circular recesses (102-105) for receiving a screw, wherein for a respective circular recess (102-105), the steel is hardened in a first region (106-109) immediately surrounding the respective circular recess and the steel is unhardened in a second region (110) immediately surrounding the first region. Component (100) according to Claim 1 , wherein a surface hardness of the hardened steel in the first region (106-109) is greater than 600 HRV and/or a surface hardness of the unhardened steel in the second region (110) is less than 350 HRV. Component (100) according to Claim 1 or 2 , wherein the hardened steel in the first region (102-105) consists of a material structure having a martensite content greater than 50%, and/or the unhardened steel in the second Region (110) consists of a material structure which is a mixed structure. Component (100) according to one of the preceding claims, wherein the hardened steel in the first region (106-109) has a thickness (D) of 0.5 to 5 mm. Component (100) according to one of the preceding claims, wherein the component (100) is a ring element for a rolling bearing. Component (100) according to Claim 5 , wherein the component (100) has a guide element (120, 121) for guiding a rolling body on an inner side (S) of the ring element or on an outer side of the ring element. Component (100) according to Claim 5 or 6 , wherein the one or more circular recesses (102-105) are arranged in the ring element such that a longitudinal axis (L) of the circular recess runs parallel to the axis of symmetry (A) of the ring element. Manufacturing device (200) for manufacturing a component (100) according to one of the preceding claims, comprising: a first processing tool for inductively hardening the steel in the first region around a circular recess, wherein the first processing tool has: a probe (202) with a probe head (204) and a coil arranged on the probe head (204), wherein the probe (202) is designed to be inserted into the circular recess, and a displacement unit (206) which is designed to move the probe head (204) along a longitudinal axis (B) of the probe. Manufacturing device (300) according to Claim 8 , comprising a second processing tool (304) which is designed to carry out a further manufacturing step for producing the component (100). Manufacturing device (300) according to Claim 9 , wherein the first machining tool (200) and the second machining tool (304) are designed to carry out the hardening of the steel and the further manufacturing step simultaneously. Manufacturing device (300) according to Claim 9 or 10 , wherein the device (300) has a common coolant circuit (320) for the first machining tool (200) and the second machining tool (304). Manufacturing device (300) according to Claim 9 until 11 , comprising a common displacement element (312) with which the first machining tool (200) and the second machining tool (304) are mechanically connected and which is designed to move the first machining tool (200) and the second machining tool (304) together. Manufacturing device (300) according to one of the Claims 9 until 11 , wherein the second machining tool (304) comprises a drill which is designed to produce a circular recess and/or the second machining tool (304) comprises a hardening tool which is designed to harden steel of a guide element (120, 121) for guiding a rolling body by means of induction. Manufacturing device (200) according to one of the Claims 8 until 12 , wherein the first machining tool comprises one or more cooling liquid outlets (210A, 210B) arranged on the probe (202) such that a cooling liquid film is formed above and/or below the coil, so that sound emission caused by inductive hardening is reduced. Method (400) for producing a component (100) according to one of the Claims 1 until 7 , comprising the following steps: producing a circular recess in a component made of unhardened steel for a mechanical device (402), inductive hardening of the steel in a first region which immediately surrounds the circular recess (404). Procedure (404) according to Claim 15 , wherein the production of a first circular recess and the hardening of a second circular recess different from the first are carried out simultaneously.

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