DE102007006986B3 - Rotor for fast running electrical machine of higher dynamics, has base body, which is formed as hollow shaft made of fiber reinforced plastic is arranged between bearing seats - Google Patents

Abstract

The rotor (1) has a base body (4), which is formed as hollow shaft a made of fiber reinforced plastic is arranged between bearing seats (2,3). A laminated core (5) and magnet (6) and a bandage (7) are provided on the base body in radial direction. The base body has a form-fit contour corresponding to the laminated core in the area of the arrangement of the laminated core. A cooling channels are provided between base body and laminated core. Radial cooling holes are arranged in the base body, which connects the hollow space of the base body with the cooling channels.

Description

The The invention relates to a rotor for a high-speed electric machine, such as a Motor and generator, which due to its construction for high speeds can be used. Such rotors are also referred to as high-speed rotor.

Also The invention relates to electrical machines by the light Construction and the low moment of inertia a special have good dynamic behavior during acceleration and braking.

Generic rotors are special due to the high speeds and the high dynamics Exposed to stress. To lessen these burdens exists in the art the effort preferably develop lightweight rotors. Thus rotors are already out fiber reinforced Plastic materials used.

For example, after the DE 693 03 031 T2 a fiber-reinforced rotor is known, which has a multilayer cylindrical structure, wherein the magnetic filler material is arranged between and in the layers. This construction has the disadvantage that it is very expensive to produce and, moreover, that the mechanical properties of the layers are adversely affected.

After DE 43 20 894 C2 a rotor for electrical machines and a method for producing the same is known, wherein the rotor of a rotor core and a rotor shell is constructed, which has a radially supporting the rotor core bandage of fiber reinforced plastic. This construction is characterized in that the rotor core has an outer lateral surface with a small cone angle, on which the rotor shell is supported with an inner lateral surface having the same cone angle and that the rotor shell has a protective layer between the inner lateral surface and the bandage. The connection of rotor core and rotor shell with a slight cone angle is not form-fitting because of the load in the circumferential direction, but only positively or in a bond also cohesively formed. A disadvantage of this invention is that no minimum and uniform air gap can be maintained across the length of the magnet region.

From the DE 27 33 833 A1 a fiber-reinforced rotor emerges, which has at least one fiber-reinforced outer ring, which is arranged coaxially around a rotor inner part, wherein the rotor part has a conical outer surface. The fiber-reinforced sleeve is arranged on the outer surface of an inner conical intermediate sleeve, whose conicity corresponds to that of the rotor part. The intermediate sleeve with the fiber-reinforced outer sleeve is firmly connected to the inner rotor part. These mentioned constructions also have the disadvantage that a minimal and uniform air gap over the length of the magnetic region can not be maintained by means of a conical connection.

Furthermore, from the DE 20 2006 012 412 U1 an electric motor with a hollow shaft known, wherein the hollow shaft for the purpose of a positive connection with components having longitudinally extending notches.

The The object of the invention is now a rotor for fast to train running electrical machines, which the extremely high loads at big Speeds grown mechanically, which also lighter Design is and the above In addition, efficiently coolable is.

The Task is done by a rotor for fast current electrical machines and machines of high dynamics solved which characterized in that a designed as a hollow shaft body made fiber reinforced Plastic is provided between bearing seats and that at least a laminated core and magnets and a bandage in the radial direction on the body are arranged, wherein the base body in the region of the arrangement the laminated cores one with the laminated cores corresponding positive contour has and that provided between the main body and laminated core cooling channels are. In the body are radial cooling air holes arranged, which connect the cavity of the body with the cooling channels.

Especially Advantageously, the object is achieved in that the positive contour is formed in cross-section as a polygon.

Around thermally relieving the rotor construction are between the body and the Bleckpaket provided the cooling channels.

Farther It is advantageous if the cooling channels in the Corners of the common polygonal cross-section of laminated core and body are arranged. An efficient design of the cooling will achieved in that in the body Cooling air holes are arranged radially, which the hollow frame of the body with connect the cooling channels, whereby a transport, for example, of cooling air over the Hollow shaft radially outward can be done.

According to a further embodiment of the invention, the connection between the laminated core (magnetic return) and the base body as a Performed shrinking, which is further improved by the fact that an additional adhesive bond is performed.

Especially stiff and light at the same time is a construction in which the main body made of carbon fiber reinforced Plastic, also called CFK, is executed.

The Invention is advantageously further developed in that the rolling bearings of the rotor are mounted on metallic bearing seats, which have a Combination of shrink connection and adhesive bond with the main body CFK are connected. The shrink bonding of the bearing seats takes place with a small excess. In order to connected are the increase the tangential stiffness and the relaxation factor of the fiber reinforced rotor in these areas by circumferential layers with a fiber orientation of 90 °.

The Bearing seats can finished after their assembly on the body machining which are extraordinary good accuracy and concentricity can be achieved.

To An advantageous development of the invention is a metallic Insert for the forwarding of the torque used. The insert is already working in the manufacturing process of the CFRP basic body connected to this. For this purpose, the metallic insert on its lateral surface over a specially developed method with nubs. The pimples serve the positive Connection with the fiber reinforced Plastic. The nubs are defined in distance and orientation arranged so that a secure and straight-line storage of the reinforcing fibers in the interstices the nubs in the winding process possible is.

The Forwarding of the torque takes place by an internal toothing, which of the transmission on a connected shaft is used. To reduce the jump in stiffness the cross-section of the insert is tapered.

The provided Zentrierfase allows safe machining of the rotor on machine tools (Turning, milling, Grinding machines). The torque transmission from the milling machine on the rotor is over Grooves in the face of the Inserts. The joining the output insert is already in the winding process, so that a positive and cohesive Connection between the bearing sleeve and the main body arises. The winding core is made split to allow demolding.

The Method of making the nubs on the insert based on that grooves by means of a gear milling machine and a suitable cutter with helix angles be milled from 45 ° and -45 °. Due to the two opposite groovings arise on very efficient and cost-effective Way the pimples.

The Concept of the invention involves the combination of various Individual elements which find a uniform expression in the rotor according to the invention.

A advantageous embodiment of the inventive concept is that an optimized layer structure used in the fiber-reinforced plastic rotor becomes. The fiber orientation is for high axial and torsional rigidity designed. This is according to a particular embodiment of the invention achievable by having different carbon fibers in one Component be used. To achieve a high longitudinal stiffness are called "ultra high modulus fibers" (UHM fibers) for the longitudinally oriented Fiber layers used. For the torsional stiffness and strength become standard carbon fibers in 45 ° orientation used.

One Another approach to improve the rotor properties in that an optimized cross-sectional geometry of the laminated core is used. This is that a thinning of the Sheets are made in areas of low magnetic flux, causing on the one hand the formation of cooling channels between the fiber reinforced Pipe and the laminated core possible and on the other hand a saving of mass is achieved. This has a positive effect on the achievable bending-critical speed.

One Another approach, which is realized in the inventive concept is, is that a cooling the laminated core takes place by means of air blown into the rotor. This gets over the hollow shaft over Radial bores in fiber reinforced Pipe in the cooling channels, the yourself between the fiber reinforced Tube and the laminated core are.

The high requirements in terms of stiffness, strength, accuracy and concentricity to fast rotating rotors are achieved by that a secure and centering connection between laminated core and fiber reinforced Pipe through a form-fitting Connection is realized. This is especially advantageous thereby improving it with a slight shrink fit and bonding is combined.

The problems due to thermal expansion is structurally counteracted by the fact that the laminated core and the fiber-reinforced tube in meh rere individual sections are divided, resulting in a reduction of the connection load due to thermal expansion between laminated core and fiber reinforced pipe. At the same time the joining process is simplified.

The inventive solution has a number of special advantages.

When general advantages of the construction method are to be called that a particularly high bending-critical speed despite the relatively large bearing distance due the high axial stiffness of the rotor according to the invention and the low Net weight of the fiber reinforced Plastic, especially the CFRP rotor, can be reached.

Farther becomes a very small mass moment of inertia due to small diameter and low density of the rotor used fiber reinforced Plastic achieved. This favors the high dynamics of the rotor in the electric machine. According to the concept The invention uses metals only in the areas in which the plastic due to its physical and mechanical Properties is unable to perform the required functions to fulfill. This concerns areas for the magnetic inference, the bearing seats and the mechanical downforce. The low moment of inertia leads to a high acceleration capacity a powered as a motor or generator electric machine.

One Another particular advantage to be highlighted is that the rotor having a particularly low mass, which is achievable thereby, that consistently fiber reinforced Plastic is used. The lower mass is especially in the Case of mobile use of the electric motor / generator as a vehicle drive or something like that noticeable.

Farther is compared to designs that work without laminated cores, also a reduction of the eddy currents and thus a reduction of the heat input reachable in the rotor through the lathed conclusion. advantages in terms of The above-mentioned comparable constructions also exist in the lower mass and the smaller moment of inertia. Likewise, on the use of expensive metals, such as titanium, are dispensed with, which is not only very expensive, but also very difficult is to be processed and a relatively low modulus of elasticity having.

The Production method of the knobs for the positive connection between CFRP pipe and insert by means of a gear milling machine is particularly advantageous because there is no other method which Such complicated geometries so fast, efficient and thus economical can produce.

The Production of individual parts and assembly of the entire assembly are in a particularly advantageous manner with conventional manufacturing methods possible. There are usual Processes such as winding, turning, milling, grinding and gluing, for use. Particularly noteworthy is that the required Accuracies for fast rotating components with the described construction feasible are.

Further Details, features and advantages of the invention will become apparent the following description of embodiments with reference on the associated Drawings. Show it:

1 : perspective view of a rotor,

2 FIG. 2 cross section through a rotor according to the invention in the region of the laminated core, FIG.

3 FIG. 5: longitudinal section through a rotor according to the invention in indicated clamping for machining, FIG.

4a : Insert for torque output with internal toothing and nubs,

4b : Longitudinal section through the insert and

4c : Axial view of the insert.

In 1 a rotor according to the invention is shown in perspective and truncated schematic, with details are shown in enlargement. In the embodiment, the rotor has 1 a rotor outer diameter of 73 mm. The rotor 1 becomes axial through two bearing seats 2 . 3 limited, between which a basic body 4 is arranged. The main body 4 consists of a fiber-reinforced material, in this case of a carbon fiber reinforced plastic. The bearing seats 2 . 3 are by combined shrink-adhesive joints centered with the body 4 connected. Between the camp seats 2 . 3 are layer by layer the laminated core 5 , the magnets 6 and the bandage 7 made of CFRP 7 arranged.

The metallic insert 10 becomes during the manufacturing process of the main body 4 associated with this.

The metallic shaft end 9 is centering by means of longitudinal press fit in combination with an adhesive bond with the body 4 connected. This serves in addition to the attachment of a rotation angle sensor also to support the ground body 4 in the region of the bearing seat fixed by a shrink connection 3 ,

In 2 is the cross section of the rotor 1 in the field of magnets 6 shown. In the radial direction is the hollow core of the formed as a hollow shaft body 4 to see. In the radial cross-sectional representation is particularly easy to see that the main body 4 by machining surfaces in the form of the basic body contact surfaces 12 having.

This is done for example by grinding or milling of the body 4 , which creates an octagon with rounded corners in cross section. The basic body contact surfaces 12 be in the joining process with the laminated core inside surfaces 11 shrinking contacted. The bleck package 5 or the inner contour of the same with the laminated core inner surfaces 11 is executed correspondingly as a polygon and also has rounded corners. In the area of the rounded corners of the main body 4 thereby arise cooling channels 13 , which can be flowed through in the axial direction. The cooling air for the cooling channels 13 is supplied via radial cooling air holes 14 showing the cavity of the hollow shaft with the cooling channels 13 connect. On the laminated core 5 are the magnets 6 and - concluding to the outside - the bandage 7 arranged.

The distributed on the circumference flat contact surfaces on the body 4 in the form of the basic body contact surfaces 12 are produced by means of cutting processes on the CFRP pipe. The by the cylindrical contour, connected to the polygonal cross-section, realized positive connection between the laminated core 5 and the CFRP pipe 4 enables safe torque transmission. The centering of the prefabricated laminated core 5 with the magnets 6 on the CFRP pipe 4 done with a slight interference fit by means of shrink bonding.

With a Reinklebung in the order of 0.1 to 0.5 mm adhesive gap, the required accuracy can not be guaranteed. With a press fit on a round component without form fit, which would also cause a very good centering, in turn, the torque can not be transferred. The circumferentially relatively soft CFRP pipe 4 would not stand the required high excesses.

The sheets or the laminated core 5 . 8th are / is thinned out in the middle of the poles in the area of low magnetic flux in order to save mass on the one hand and cooling channels on the other hand 13 to form, through which the injected cooling air can flow. The reduction in mass contributes to increasing the critical speed and the dynamics.

3 shows the additional features of metallic insert 10 and metallic shaft end 9 during the machining of the body 4 and the bearing seats 2 . 3 after their assembly. The metallic insert 10 and the metallic shaft end 9 are equipped with centering chamfers, which are centering accurate and fixed clamping in machine tools (turning, milling and grinding machines) between so-called centering tips 15 . 16 serve.

4 shows in three partial views of the output side of the rotor 1 , In the 4a is in perspective the metallic insert 10 with an internal toothing 17 and the pimples 18 shown. With the internal toothing 17 The torque can be transmitted to the connected shaft.

The pimples 18 serve for positive and cohesive connection of insert and CFRP pipe basic body 4 , The connection already occurs during the production process of the main body in the winding process.

For the production of nubs 18 serves a method in which by means of a gear milling machine grooves are milled in two opposite directions offset by 90 °.

In 4b is the metallic insert 10 shown in a longitudinal section. To recognize the internal gearing 17 as well as the pimples 18 , Likewise, the tapered design of the metallic insert 10 to recognize which the stiffness jump to the main body 4 reduced.

4c shows a front view in the axial direction of the metallic insert 10 , which in turn radially from inside to outside the internal teeth 17 and the pimples 18 shows.

Claims (10)

Rotor for a high-speed electrical machine of high dynamics, characterized in that a hollow body formed as a base body ( 4 ) made of fiber-reinforced plastic between bearing seats ( 2 . 3 ) is provided and that at least one laminated core ( 5 ) and magnets ( 6 ) as well as a bandage ( 7 ) in the radial direction on the base body ( 4 ) are arranged, wherein the main body ( 4 ) in the region of the arrangement of the laminated cores ( 5 ) one with the laminated cores ( 5 ) has a corresponding positive contour and that between base body ( 4 ) and laminated core ( 5 ) Cooling channels ( 13 ) are provided, wherein in the base body ( 4 ) radial cooling air holes ( 14 ) are arranged, which the cavity of the body ( 4 ) with the cooling channels ( 13 ) connect. Rotor according to claim 1, characterized gekennzeich net, that the form-fitting contour is formed in cross section as a polygon. Rotor according to claim 2, characterized in that the cooling channels ( 13 ) in the corners of the common polygonal cross section of laminated core ( 5 ) and basic body ( 4 ) are arranged. Rotor according to one of claims 1 to 3, characterized in that the connection between the laminated core ( 5 ) and basic body ( 4 ) is designed as a shrink connection. Rotor according to one of claims 1 to 4, characterized in that the connection between the laminated core ( 5 ) and basic body ( 4 ) is additionally designed as an adhesive connection. Rotor according to one of claims 1 to 5, characterized in that the basic body ( 4 ) is made of carbon fiber reinforced plastic CFK. Rotor according to one of claims 1 to 6, characterized in that the connection between the bearing seats ( 2 . 3 ) and the basic body ( 4 ) is designed as a shrink connection. Rotor according to one of claims 1 to 7, characterized in that the connection between the bearing seats ( 2 . 3 ) and the basic body ( 4 ) is additionally designed as an adhesive connection. Rotor according to one of claims 1 to 8, characterized in that one with nubs ( 18 ) provided insert ( 10 ) in the production of the basic body ( 4 ) in the winding process in the body ( 4 ) is inserted. Rotor according to claim 9, characterized in that the nubs ( 18 ) are formed by milling of grooves offset by 90 ° in their direction by means of a gear milling machine.