DE102006000927A1 - Coaxial connection for gradient coil of magnetic resonance device, has contact and insulating bushes which move relative to contact bolt under development of reset force when connector is connected with counter connector - Google Patents

Abstract

The connection has a connector (4) with a center contact bolt accommodated in an insulating bush (14). The insulating bush is accommodated in a contact bush (16). A counter connector (5) has a center counter contact bolt (26) held in another insulation bush accommodated in a counter contact bush, which cooperates with a retaining holder for connecting the connector with the connector (5). The contact bush (16) and the insulating bush move relative to the contact bolt under the development of a reset force when the connector is connected with the connector (5).

Description

High-current coaxial connection, especially for connection a current-carrying coaxial line to a gradient coil of a Magnetic resonance apparatus, and gradient coil with connected high-current coaxial line

The The invention relates to a high-current coaxial connection, in particular to connect a current-carrying coaxial line to a gradient coil of a Magnetic resonance apparatus.

Magnetic resonance devices are for a long time in medicine and in biophysics for extraction from pictures inside the body of an examination subject. Magnetic resonance imaging based on the physical phenomenon of nuclear magnetic resonance. The object under investigation becomes a strong, constant magnetic field exposed, whereupon the previously irregular in the examination object oriented nuclear spins align the atoms in the magnetic field and via high frequency waves Vibrations are excited, which vibrations the actual Measurement signal (RF response signal) for to represent the imaging. The measuring signal is provided with suitable receiver coils added.

requirement for the Imaging is a precise information about the respective place of origin a measurement signal related to the examination object. This information is also called location information or location coding. Served for this you look at magnetic gradient fields that are along the three spatial directions produced by means of individual coils won. The individual coils are one usually summarized cylindrical gradient coil. The term "gradient coil" becomes a single coil system denotes the multiple individual coils associated with the three spatial directions includes, which is received and fixed in a suitable potting compound are.

To generate the gradient fields, a high current is passed over the gradient coils, the current being several 100A. Out US 5,394,086 it is known to supply the current via a high-current coaxial line. This consists of at least one forward conductor, which is usually guided in the middle of the conductor, and at least one return conductor, which is arranged, for example concentrically and in isolation around the forward conductor. The supplied current and the recirculated current thus flow parallel to each other, but in opposite directions, so that there are no disturbing magnetic fields that could adversely affect the operation of the magnetic resonance system.

To the Connect the two lines of high-current coaxial line are the individual lines split on the gradient coil and on corresponding contacts, the coil side are provided, screwed. So here will be the coaxial positional relationship of the individual lines is canceled. This is however, to the detriment of interactions between the applied and generated magnetic fields comes. There will be forces (in usually Lorentz forces) on the split individual lines exercised, due to the alternating fields comes it leads to vibrations in the contact area, which is disadvantageous overall is, and in particular, after the individual lines in this Area are freely movable, often to image disturbances, so-called spikes, comes.

Of the Invention is therefore the object of a possibility for improved connection a high current coaxial line to indicate a third object, in particular a gradient coil.

to solution This problem is provided by a high-current coaxial connection consisting of a plug and a detachably connectable mating plug, the plug being a central, axially against in one direction a restoring force slidably received in an insulating bushing contact pin comprising which insulating bushing received in a contact socket is that overlapped by one of the connection with the mating connector serving union holder is while the Mating connector has a central mating contact pin, the in a Isolierbuchse is supported, which in turn in a mating contact socket, for connecting the plug with the mating connector with the cap holder cooperates, is added, while connecting the plug with the mating connector, the contact socket and the insulating bushing relative to the voltage applied to the mating contact pins contact pin under construction the restoring force moves and the contact socket in contact with the mating contact socket is brought.

According to the invention, a coaxial connection is proposed which is designed and / or capable of carrying high currents in the range of 500A-600A or more. It comprises a plug and a mating connector, which can be connected to each other, including a cap holder, which is arranged on the plug, is provided, which in turn cooperate with corresponding holding means on the mating connector, which are provided on the mating contact socket. The cap holder may preferably be designed as a union nut on the mating contact an external thread is provided on the union nut is screwed over what an extremely strong, non-positive contact of the bolt and sleeve contacts can be achieved. While the sleeve contacts are firmly pressed against each other on the cap holder, special precautions are taken to realize an extremely strong, positive and non-positive contacting of the respective pin of the plug and the mating connector. For this purpose, according to the invention, the contact pin on the plug is axially movable and displaceable against a restoring force. The contact plug is applied to the mating connector, the subsequent fixed connection via the cap holder causes, on the one hand, the socket contacts are moved toward each other and closed, and at the same time the contact bushing and the insulating bush are moved axially relative to the contact bolt against contact pin, thereby the restoring force is built up. The contact pin is thus pressed over this restoring force building up against the mating contact pin, so that here too an extremely strong, non-positive and positive contact is achieved when the coaxial connection is completely plugged together.

Especially based on the application of the connection of a coaxial line to a gradient coil, there are a number of advantages. Because Unlike in the past, there is no split into two individual lines, Rather, the coaxial connector is located right up to that on the coil Mating plug out. The gradient current flows So also in this connection area coaxial. Anything from the resulting magnetic fields resulting forces are not generated or act not on the connection, it comes to no vibration, the Spike hazard is minimized after there are no free moving parts gives. Furthermore assembly is also much easier, after only the two plug parts are to be connected.

At the Contact bolt itself is expediently a counter bearing for a bearing for Isolierbuchse, the restoring force generating spring element or spring element package provided. For example, as an abutment an annular Expansion of the contact pin serve. However, it is advantageous as a counter bearing screwed onto the contact pin socket to use. about This bushing, on an external thread the bolt is screwed, the bias of the spring element or the package, depending on how far the mother is is screwed on. As a spring element comes expediently a plate spring used, a spring element package can consist of several be formed successively arranged disc springs.

Around the high pressure forces the spring element or the spring element package on the insulating bush to be able to record safely and without deformation of the insulating bush, is the spring element or the spring element package expediently on a voltage applied to the insulating bushing bearing disc, so a simple metal ring, superimposed.

The High-current coaxial connection according to the invention should continue to be designed so that for a given investment the contact pin on the mating contact pin before connecting the cap holder with the mating contact socket a gap between the contact socket and the mating contact bushing of 0.4-1.2 mm, in particular given by 0.5-08 mm is that when connecting the cap holder is closed with the mating contact socket. That is, immediate with the joining the two connector parts is the contact pin on the mating contact pin on, but the two contact sockets are still around each other Gap away. By connecting the cap holder with the mating contact socket, So for example with the screwing of the union nut on the external thread the mating contact socket, the gap is closed after the cap holder moved axially to the mating contact socket, so for example on this is screwed while the contact socket with insulating bushing entraining. The insulating bush is doing relative to the contact pin moves, this slides axially in the insulating bush or the insulating bushing slides axially along the contact pin, wherein the spring element is further tensioned. The unscrewing movement of the cap holder goes until the two contact sockets frictionally against each other lie.

Around a control option to have that the two contact sockets also lie together, is expediently on the cap holder at least one lateral viewing aperture to the contact area the contact socket provided with the mating contact socket, for example in the form of an axial or oblique to the longitudinal axis extending viewing slot or the like.

in the With regard to the high currents to be transmitted all current-carrying elements sufficiently strong dimensioned and designed. The diameter of the contact pin and the counter-contact pin should in the range between 5-15 mm, the wall thickness the contact and the mating contact socket should be between 3 and 8 mm, wherein the inner diameter of the respective socket and the strenght the respective insulating bush is chosen so that a sufficient Insulation distance is given to the respective contact pin. The the counter bearing serving sleeve as well as the cap holder can be made of stainless steel, for example, as they are not responsible for the power supply are.

Next the high-current coaxial connection, the invention further relates to a Gradient coil with connected high-current coaxial line as part of a magnetic resonance apparatus, wherein This arrangement is characterized in that the coaxial line via a High current coaxial connection of the type described above is.

Of the Plug is connected to the high-current coaxial line, while the mating connector is arranged on the gradient coil. This is there with particular advantage firmly cast or laminated, therefore virtually insoluble connected to the gradient coil. Before pouring or Lamination of the mating connector is of course with the appropriate Gradient coils have been contacted. The positive and positive pouring or Lamination of the mating connector ensures that it is in the connection area does not come to any movements or relaxations of the connection and over it the entire operating time a safe, störunanfällige power connection is realized.

Of the Hinleiter the high-current coaxial line, usually the center running Ladder, is expediently with the contact pin and the return conductor, usually the radial encompassing conductor is connected to the contact socket by a welding, in particular a laser welding connection, a solder joint or a crimp connection connected. The used high-current coaxial line itself is advantageous for guiding a current of at least 500A, in particular of at least 600A designed.

Further Advantages, features and details of the invention will become apparent the embodiment described below and with reference to the Drawing. Show

1 a high-current coaxial connection according to the invention, used for contacting a high-current coaxial line with a gradient coil, in the still open state, and

2 the high-current coaxial connection 1 in the closed state.

1 shows a high current coaxial connection 1 for connecting a high-current coaxial line according to the invention 2 with a gradient coil 3 or one or more embedded therein, not shown in detail individual coils is used. The high-current coaxial connection according to the invention 1 consists of a plug 4 and a mating connector 5 , The plug 4 is with the coaxial line 2 connected while the mating connector 5 in the potting compound 6 the gradient coil 3 is poured, of course, after previously contacted with the corresponding associated single coil, which is not shown in detail.

The plug 4 is designed as a rotationally symmetrical component and has a centrally disposed contact pin 7 on, which has a flat contact surface 8th has, with which he at a corresponding contact surface on the opposite mating contact pin of the mating connector 5 which will be discussed below. At the front end is the contact pin with an external thread 9 provided on the in the example shown a sleeve 10 is screwed on, as an abutment for a spring element 11 , here a plate spring 12 serves. Instead of a single plate spring 12 could also be a disc spring set consisting of several consecutively connected disc springs are used. The spring force would then be increased accordingly.

In the 1 shown disc spring 12 rests on a bearing disc 13 which in turn is connected to an insulating bushing 14 rests. The insulating bush takes the contact pin 7 on, he is absorbed in her axially movable. The insulating bush has an annular projection at its front end 15 on, on which the bearing disk 13 rests. The approach 15 is limited edge, the diameter is such that the bearing disc 13 is recorded with little play.

Furthermore, a contact socket 16 provided a cylindrical area 17 in which the cylindrical portion 18 the insulating bush 14 intervenes. Again, there is an annular shoulder 19 provided in a cylindrical section 33 passes. On the shoulder 19 again lies the annular approach 15 the insulating bush 14 on, so it can be moved axially over this connection.

Also provided is a cap holder 20 in the form of a union nut 21 , which is provided with an internal thread and an end-side flange 22 which has the annular shoulder 19 the contact socket 16 engages behind.

Visible is the central, axially extending Hinleiter 23 the coaxial line 2 via a corresponding welding, soldering or crimping with the contact pin 7 connected. The one about isolation 24 spaced circumferential return conductors 25 is via a corresponding welding, soldering or crimping with the contact socket 16 connected. Not shown in detail is the outer insulation layer of the coaxial line 2 ,

The mating connector 5 also has a mating contact pin 26 on, which has a front contact surface 27 that looks like the contact surface 8th is plane, so that both contact surfaces 8th . 27 lie positively against each other. The mating contact pin is in an insulating bushing 28 taken, in turn, in a mating contact socket 29 is arranged. Visible is the mating connector 5 as stated in the potting compound 6 the gradient coil 3 poured, thus fixed so fixed.

1 shows the coaxial connection 1 when not closed. Although the two contact surfaces 8th and 27 to each other, that is, the contact pin and the mating contact pin 26 touch each other. However, the contact socket 16 not with the mating contact socket 29 connected, the two contact surfaces 30 . 31 are over a gap 32 separated from each other. The gap width is approx. 0.5-08 mm. In 1 For example, was the union nut 21 already something on the external thread on the counter bearing bush 29 unscrewed, but not yet so far that a movement of the contact socket 16 including insulation sleeve 14 axially to the mating connector 5 is done. Only together are the contact pins 7 and the mating contact pin 26 ,

For producing a current-carrying contact now the union nut 21 continue on the mating contact socket 29 screwed. So it becomes the gradient coil 3 moved axially. As a result of overlapping of the flange 22 over the annular shoulder 19 the contact socket 16 this is taken, she takes in turn the insulating sleeve 14 with, which in turn takes the bearing disc axially. The plate spring 12 is with its inner end to the socket 10 mounted in a fixed position on the contact pin 7 screwed, which in turn is fixed on the mating contact pin 26 is applied. So here there is no movement, it will only be the parts surrounding the contact pins on the Aufschraubbewegung relative to the contact pin 7 moved axially. As a result of the movement of the bearing disc 13 to the mating connector 5 towards is inevitably the diaphragm spring 12 compressed, see 2 , The Aufschraubbewegung and thus the spring compression takes place until the two contact surfaces 30 . 31 the contact socket 16 and the mating contact socket 29 frictionally and positively abut each other. This current-carrying connection is made by the force generated by screwing between the union nut 21 and the counter bearing bush 29 generated. Likewise, the contact pins 7 and the mating contact pin 26 positively and positively contacted with each other, wherein the frictional connection and the fixed connection on the tensioned plate spring 12 is obtained.

Not shown in detail, but expediently provided, is a Sichtdurchbrechung in the union nut 21 , This is such that they always have a view of the contact surfaces of the contact socket to be contacted 16 and the mating contact socket 29 allows. This can be checked visually, whether both contact surfaces 30 . 31 firmly against each other when the union nut 21 is screwed on.

At It should be noted that it is with the high-current coaxial connection according to the invention not only possible is a contacting a coaxial line with a gradient coil ensure, in this case, the mating connector positional is poured. Rather, it would be It is also conceivable, the mating connector with a continuing To connect coaxial line. Of course, the coaxial connection in a corresponding insulating housing to detect the exposed, live Encapsulate parts.

Claims (14)

High-current coaxial connection, in particular for connecting a current-carrying coaxial line to a gradient coil of a magnetic resonance apparatus, consisting of a plug ( 4 ) and with this releasably connectable mating connector ( 5 ), whereby the plug ( 4 ) a central, axially displaceable in one direction against a restoring force in an insulating bushing ( 14 ) received contact pins ( 7 ), which insulating bushing ( 14 ) in a contact socket ( 16 ) received by one of the connection with the mating connector ( 5 ) serving union holder ( 20 ), while the mating connector ( 5 ) a central counter-contact pin ( 26 ), which in an insulating bushing ( 28 ), which in turn in a mating contact socket ( 29 ) used to connect the plug ( 4 ) with the mating connector ( 5 ) with the cap holder ( 20 ) is received, wherein when connecting the plug ( 4 ) with the mating connector ( 5 ) the contact socket ( 16 ) and the insulating bush ( 14 ) relative to the mating contact pin ( 26 ) adjacent contact pins ( 7 ) moved under construction of the restoring force and the contact socket ( 16 ) in contact with the mating contact socket ( 29 ) is brought. High-current coaxial connection according to claim 1, characterized in that on the contact pin ( 7 ) an abutment for an insulating bush ( 14 ) against counter-bearing, the restoring force generating spring element ( 11 ) or spring element package is provided. High-current coaxial connection according to claim 2, characterized in that the abutment of a on the contact pin ( 7 ) screw-on socket ( 10 ) is formed. High-current coaxial connection according to claim 2 or 3, characterized in that the spring element ( 11 ) a plate spring ( 11 ) Is or the spring element package consists of several successively arranged disc springs. High-current coaxial connection according to one of claims 2 to 4, characterized in that the spring element ( 11 ) or the spring element package on one of the insulating bushing ( 14 ) adjacent bearing disk ( 13 ) is stored. High-current coaxial connection according to one of the preceding claims, characterized in that for a given contact of the contact pin ( 7 ) on the mating contact pin ( 26 ) before firmly connecting the cap holder ( 20 ) with the mating contact socket ( 29 ) A gap ( 32 ) between the contact socket ( 16 ) and the mating contact socket ( 29 ) of 0.4-1.2 mm, in particular of 0.5-0.8 mm, when connecting the cap holder ( 20 ) with the mating contact socket ( 29 ) is closed. High-current coaxial connection according to one of the preceding claims, characterized in that the cap holder ( 20 ) a union nut ( 21 ) with an internal thread and the mating contact socket ( 29 ) has an external thread. High-current coaxial connection according to one of the preceding claims, characterized in that on the cap holder ( 20 ) at least one lateral viewing aperture to the contact region of the contact socket ( 16 ) with the mating contact socket ( 29 ) is provided. High-current coaxial connection according to one of the preceding claims, characterized in that the contact and the mating contact pins ( 7 . 26 ) and the contact and the mating contact socket ( 16 . 29 ) are made of copper. Gradient coil with a connected high-current coaxial line as part of a magnetic resonance apparatus, characterized in that the coaxial line ( 2 ) via a high-current coaxial connection ( 1 ) is connected according to one of claims 1 to 9. Gradient coil with a connected high-current coaxial line according to claim 10, characterized in that the plug ( 4 ) with the high-current coaxial line ( 2 ), while the mating connector ( 5 ) at the gradient coil ( 3 ) is arranged. Gradient coil with a connected high-current coaxial line according to claim 11, characterized in that the mating connector ( 5 ) at the gradient coil ( 3 ) is poured or laminated. Gradient coil with a connected high-current coaxial line according to claim 11 or 12, characterized in that the forward conductor ( 23 ) of the high-current coaxial line ( 2 ) with the contact pin ( 7 ) and the return conductor ( 25 ) of the high-current coaxial line ( 2 ) with the contact socket ( 16 ) is connected by a welding, in particular a laser welding connection, a solder connection or a crimp connection. Gradient coil with connected high-current coaxial line according to one of Claims 10 to 13, characterized in that the high-current coaxial connection ( 1 ) is designed to carry a current of at least 500A, in particular of at least 600A.