Rotary anode arrangement and X-ray tube

Abstract

The embodiments relate to a rotary anode arrangement with a rotary anode, a rotor for driving the rotary anode and a stator, which exerts a torque on the rotor. The stator includes at least one coil for generating a first magnetic field and at least one permanent magnet for generating a second magnetic field. The embodiments also relate to an X-ray tube with the rotary anode arrangement. The embodiments offer the advantage that a high electromagnetic utilization is possible with a synchronous motor that is excited by permanent magnets.

Claims

1. A rotary anode arrangement comprising: a rotary anode; a stator configured to exert a torque on a rotor, the stator comprising a stator housing and a plurality of stator tooth modules arranged at regular intervals along a circumference of the stator housing, wherein each stator tooth module of the plurality of stator tooth modules comprises two stator tooth halves having a first soft-magnetic material; a plurality of coils arranged in the stator for generating a first magnetic field; a plurality of permanent magnets arranged in the stator for generating a second magnetic field, wherein the plurality of coils and the plurality of permanent magnets are arranged along a circumference of the stator housing, wherein only a single permanent magnet of the plurality of permanent magnets is arranged in a center of each stator tooth and extending in a radial direction between an end of a respective stator tooth and the circumference of the stator housing, and wherein each respective coil of the plurality of coils is wound around two respective stator tooth halves and the respective permanent magnet positioned therebetween; and the rotor arranged within the stator for driving the rotary anode, wherein the rotor is configured for a magnetic return path and is free of magnetic sources, and wherein the rotor has a toothed structure in a direction of rotation of the rotor.

2. The rotary anode arrangement as claimed in claim 1, wherein the rotor comprises a second soft-magnetic material.

3. The rotary anode arrangement as claimed in claim 1, wherein the rotary anode comprises an anode plate and a shaft bearing the anode plate, wherein the shaft is connected to the rotor.

4. The rotary anode arrangement as claimed in claim 1, wherein adjacent permanent magnets of the plurality of permanent magnets are arranged with alternate polarities.

5. The rotary anode arrangement as claimed in claim 2, wherein the rotary anode comprises an anode plate and a shaft bearing the anode plate, wherein the shaft is connected to the rotor.

6. An X-ray tube comprising: a rotary anode arrangement comprising: a rotary anode; a stator configured to exert a torque on a rotor, the stator comprising a stator housing and a plurality of stator tooth modules arranged at regular intervals along a circumference of the stator housing, wherein each stator tooth module of the plurality of stator tooth modules comprises two stator tooth halves having a first soft-magnetic material; a plurality of coils arranged in the stator for generating a first magnetic field; a plurality of permanent magnets arranged in the stator for generating a second magnetic field, wherein the plurality of coils and the plurality of permanent magnets are arranged along a circumference of the stator housing, wherein only a single permanent magnet of the plurality of permanent magnets is arranged in a center of each stator tooth and extending in a radial direction between an end of a respective stator tooth and the circumference of the stator housing, and wherein each respective coil of the plurality of coils is wound around two respective stator tooth halves and the respective permanent magnet positioned therebetween; and the rotor arranged within the stator for driving the rotary anode, wherein the rotor is configured for a magnetic return path and is free of magnetic sources, and wherein the rotor has a toothed structure in a direction of rotation of the rotor, wherein the rotor is arranged within an X-ray sleeve of the X-ray tube, and the stator is arranged outside the X-ray sleeve of the X-ray tube.

7. The X-ray tube arrangement as claimed in claim 6, wherein the rotor comprises a second soft-magnetic material.

8. The X-ray tube arrangement as claimed in claim 6, wherein the rotary anode comprises an anode plate and a shaft bearing the anode plate, wherein the shaft is connected to the rotor.

9. The X-ray tube arrangement as claimed in claim 7, wherein the rotary anode comprises an anode plate and a shaft bearing the anode plate, wherein the shaft is connected to the rotor.

10. The X-ray tube arrangement as claimed in claim 6, wherein adjacent permanent magnets of the plurality of permanent magnets are arranged with alternate polarities.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts a longitudinal section through an X-ray tube in accordance with the prior art.

(2) FIG. 2 depicts an embodiment of a longitudinal section through an X-ray tube including a rotary anode arrangement.

(3) FIG. 3 depicts a cross section through the stator and rotor of the rotary anode arrangement.

DETAILED DESCRIPTION

(4) FIG. 2 depicts a longitudinal section through an X-ray tube 101 including a rotary anode arrangement. An electron-emitting cathode 103 and a rotary anode 104 opposite said cathode are located in an evacuated tube sleeve 102 of the X-ray tube 101. The rotary anode 104 includes an anode plate 141 connected to a rotor 143 of an electric motor by a shaft 142. The rotor 143 is formed from a first soft-magnetic material. Soft-magnetic materials are, for example, electric or magnetic sheet steel or soft magnetic composite (SMC) materials.

(5) Outside the tube sleeve 102, a stator 105 surrounds the tube sleeve 102 in the direct vicinity of the rotor 104. The stator 105 includes a plurality of permanent magnets 152 arranged along its circumference, which permanent magnets generate a second magnetic field that acts as excitation field on the soft-magnetic rotor 143. The stator 105 generates, with coils 151 through which current is flowing and which are arranged along the circumference, at least one first magnetic field rotating about the tube sleeve 102. The permanent magnets 152 arranged in the stator 105 generate a second magnetic field (e.g., excitation field). By virtue of the interaction of the first and second magnetic fields with the rotor 143, a torque is generated, as a result of which the rotary anode 104 is caused to rotate synchronously. The permanent magnets 152 are arranged in a second soft-magnetic material 153.

(6) The electron beam 106 emitted by the cathode is accelerated towards the anode plate 141 and, on impingement on the anode plate 141, generates X-ray radiation 107 owing to deceleration, which X-ray radiation leaves the X-ray tube 101 through a beam window 108 in the tube sleeve 102.

(7) FIG. 3 depicts a cross section through the stator 105 and the rotor 143 of the rotary anode arrangement as depicted in FIG. 2. The stator 105 includes a magnetically nonconductive cylindrical stator housing 154 in which stator tooth modules 157, including stator tooth halves 155 including a second soft-magnetic material 153, for example motor laminations, are arranged at regular intervals along the circumference of the stator housing 154. Permanent magnets 152 are arranged with alternate polarity between the stator tooth halves 155. A coil 151 including copper wire is wound around in each case two stator tooth halves 155 and a permanent magnet 152, which coil forms a tooth-wound coil 156. The coils 151, owing to the current flowing through them, generate a first magnetic field, and the permanent magnets 152 generate a second magnetic field. Both magnetic fields are closed via the rotor 143, which therefore forms a section of a magnetic circuit of an electric machine.

(8) The first soft-magnetic material of the rotor 143 has a regular tooth-shaped structure. By interaction of the two magnetic fields and the rotor 143, a torque is produced that acts on the rotor 143 and is used to drive the rotary anode.

(9) For example, the stator 105 includes six wound stator tooth modules 157, with in each case one permanent magnet 152 being introduced in the center of said stator tooth modules in a radial on-edge position. The stator tooth modules 157 are wound individually and the stator 105 is constructed from the wound stator tooth modules 157. The individual coils 151 of the stator 105 formed in this way are connected to form a motor winding with three winding phases. By virtue of this modular motor design with the separate winding of the stator tooth modules 157, a high copper space factor of the coils 151 is achieved, as a result of which the efficiency is high.

(10) The operational response and driving of the motor are the same as in any known permanent magnet synchronous machine owing to a sinusoidally induced voltage.

(11) It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

(12) While the present invention has been described above by reference to various embodiments, it may be understood that many changes and modifications may be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.