Slip ring and method of assembling same

Abstract

A slip ring (1) is provided with: a first support body (30); a first electrical interface (50) associated with the first support body (30) and configured to be electrically connected to a first electrical component; the plurality of conducting rings (80) are fixedly arranged on the first supporting body (30); the plurality of first electric tracks (60) are electrically connected with the first electric interface (50) and are fixedly arranged on the first supporting body (30); a plurality of electrical contacts (70), each electrical contact (70) being electrically connected to a respective first electrical track (60) and elastically deforming when each electrical contact abuts against a respective conductive ring (80); a second support body (90) rotatably coupled to the first support body (30) about an axial rotation axis (R); a second electrical interface (110) associated with the second support body (90) and configured to be electrically connected to a second electrical component; and a plurality of brushes (130) fixedly mounted to the second support body (90) and electrically connected to the second electrical interface (110), where each brush (130) is arranged in sliding contact with a respective conductive ring (80).

Description

Technical Field

[0001] The invention relates to a slip ring for transmitting data. Background Art

[0002] Slip rings are electrical devices used on machines that have parts that rotate relative to each other to ensure an electrical connection between them. Examples of machines that commonly employ slip rings include, for example: robotic arms, rotating machine tools, turntables, wheels with integrated sensors, articulated camera mounts or other types of sensors.

[0003] Slip rings are classified into slip rings for transmitting power, which are configured to transmit high power and low frequency current between mutually rotating parts; slip rings for transmitting electrical signals are configured to transmit low power and high frequency current (usually data signals) between mutually rotating parts; and hybrid slip rings for transmitting high power and low frequency current and low power and high frequency current. "High power current" refers to current with a power greater than 1W. "Low power current" refers to current with a power less than 1W. "High frequency current" refers to current with a frequency greater than 1kHz. "Low frequency current" refers to current with a frequency less than 1kHz. Some slip rings used for power transmission can still be used to transmit current at low power and high frequency, with restrictions on the maximum frequency. Similarly, some slip rings used for electrical signals can still be used to transmit high power and low frequency current, with restrictions on the maximum power.

[0004] The slip ring usually consists of two parts that rotate with each other, each part is provided with a corresponding electrical interface. The slip ring is installed at the rotation fulcrum of the rotating part of the machine to be connected, so that one of the two parts is integrated with the fixed structure of the machine and the other part is integrated with the rotating part.

[0005] One of the two electrical interfaces is electrically connected to a plurality of conductive rings placed side by side along the rotation axis of the slip ring and alternating with insulating rings made of electrically insulating material (or empty spaces separating the conductive rings). The other electrical interface is connected to a plurality of brushes in sliding contact with the respective conductive rings so as to maintain electrical connection during the mutual rotation of the two parts of the slip ring.

[0006] In a slip ring for signal transmission, the electrical interface may consist of a corresponding multi-pin connector (e.g., a female Ethernet connector) comprising a plurality of pins or providing an area for welding a corresponding external conductor (e.g., a plurality of contact welding areas on a printed circuit board). Each pin (or welding area) is electrically connected to a corresponding conductive ring. Typically, a plurality of cables are used to connect the electrical interface to the ring, each cable being provided with one end welded to a corresponding pin (or welding area) of the electrical interface and the other end welded to a corresponding conductive ring. A plurality of cables are housed in an axial cavity defined by an assembly of conductive and insulating rings placed side by side.

[0007] Typically, to assemble this type of connector, the cable is arranged to be soldered to the corresponding pins (or soldering areas) of the electrical interface, the conductive rings and insulating rings are placed one after another near the connector, and for each conductive ring, the corresponding cable is passed through the cavity defined by the ring already in place, the end of the cable is soldered to the end of the conductive ring, the conductive ring is placed near the ring already positioned, and the next insulating ring is placed near the conductive ring.

[0008] The Applicant has observed that, especially in the case of slip rings for electrical (or mixed) signal transmission, it is of the utmost importance that the slip ring preserves the electrical signal transmitted through it, thus minimizing degradation of the transmitted electrical signal. Such degradation is usually due to electromagnetic interference between power cables (called crosstalk) and parasitic impedance between solder, conductive ring and solder brush between cable and conductive ring.

[0009] In the applicant's experience, in order to minimize this degradation of the transmitted electrical signal, the cables are arranged so that they interfere with each other electromagnetically as little as possible in the path between the multi-pin connector and the conductive ring. Typically, this is achieved by arranging the cables as twisted pairs. In addition, the soldering between the cables and the conductive ring must be performed accurately and meet very strict quality requirements, such as the amount of solder used, the thickness of the solder and the position.

[0010] The Applicant has noted that, as mentioned above, limiting the degradation of electrical signals in slip rings is particularly difficult.

[0011] In fact, in the Applicant's experience, the application of an automated industrial process for inserting the cables into the cavities can be complicated, since each cable must pass through the cavity of an already positioned ring, which is wound around another cable and welded to the corresponding conductive ring while being positioned side by side. These operations are therefore usually performed manually by an experienced operator, with the result that the repeatability of the slip ring assembly is not always ensured and that the production costs are increased as a result. Furthermore, this complicates the production of small rings, in which it is even more difficult to arrange the cables in an appropriate manner and to weld them accurately to the conductive rings.

[0012] The applicant has realised that if the need to solder the cable to the conductive ring is eliminated, assembly can be simplified, production costs can be reduced and degradation of the transmitted electrical signal can be limited.

[0013] The Applicant has also realised that if the electrical cables were replaced by electrical tracks mounted on a support, it would be possible to arrange the electrical tracks so as to minimise mutual electromagnetic interference.

[0014] The Applicant has found that if conducting rings are arranged around the support body, it is possible to arrange each electric track so that it reaches a respective conducting ring.

[0015] The applicant has also found that by arranging each electrical track to be electrically connected to a respective electrical contact and arranging such elastically deformable electrical contacts so that each conductive ring can be positioned around the support body, elastically deforming the respective electrical contact, it is possible to eliminate any solder between the electrical track and the conductive ring. Summary of the invention

[0016] Thus, in a first aspect thereof, the present invention relates to a slip ring comprising:

[0017] a first support body;

[0018] a first electrical interface associated with the first support and configured for electrical connection to a first electrical component;

[0019] A plurality of conductive rings, wherein the plurality of conductive rings are fixedly mounted on the first support body;

[0020] a plurality of first electrical tracks, the plurality of first electrical tracks being electrically connected to the first electrical interface and fixedly mounted on the first support body;

[0021] a plurality of electrical contacts, each electrical contact being electrically connected to a respective first electrical track and being elastically deformed when the electrical contact abuts against a respective conductive ring;

[0022] a second support body rotatably coupled to the first support body about an axial rotation axis;

[0023] a second electrical interface associated with the second support and configured to be electrically connected to a second electrical component;

[0024] A plurality of brushes are fixedly mounted to the second support body and electrically connected to the second electrical interface, wherein each brush is arranged in sliding contact with a corresponding conductive ring.

[0025] A second aspect of the present invention relates to a method for assembling a slip ring, the method comprising:

[0026] A first support, a first electrical interface, a plurality of first electrical tracks and a plurality of electrical contacts are provided; the first electrical interface is configured to be electrically connected to a first electrical component and is associated with the first support, the plurality of first electrical tracks are electrically connected to the first electrical interface and extend on the first support, and each electrical contact is electrically connected to a corresponding first electrical track and is elastically deformable;

[0027] applying pressure to the plurality of electrical contacts to elastically deform the plurality of electrical contacts;

[0028] arranging a plurality of conductive rings on the first support and removing the pressure from the plurality of electrical contacts such that each electrical contact contacts a corresponding conductive ring;

[0029] A plurality of brushes are coupled in sliding contact with the corresponding conductive rings, wherein the plurality of brushes are electrically connected to a second electrical interface configured for electrical connection to a second electrical component.

[0030] The Applicant has verified that the elastic deformation of each electrical contact allows each electrical contact to exert a contact pressure on the corresponding conductive ring, thereby ensuring electrical continuity between the electrical contact and the conductive ring. This makes it possible to avoid welding the first electrical track to the corresponding conductive ring.

[0031] The Applicant has also demonstrated that the electrical contacts can be elastically deformed before the conductive ring is arranged on the first support, thereby allowing an easy and convenient assembly of the conductive ring on the first support.

[0032] The Applicant has further demonstrated that the first electrical tracks can be configured to follow a predetermined and unchangeable path during use of the slip ring, which minimizes electromagnetic interference between them.

[0033] The first support and the second support of the electric ring are rotatably coupled about an axis of rotation. In the present specification and the appended claims, unless otherwise indicated, expressions such as "axial", "axially", "radially", "radially inner", "radially outer", "circumferential", "circumferentially" are used with reference to such an axis of rotation.

[0034] The term "insulating" refers to a component that is at least partially made of a material that is unable to conduct electricity because of its dielectric properties.

[0035] The term "conductive" refers to a component that is at least partially made of a material capable of carrying an electric current therein and having a resistance of less than 1 Ω.

[0036] The term "electric contact" refers to an element made of an electrically conductive material.

[0037] The term "brush" refers to an electrical component configured to obtain sliding electrical contact with an electrical conductor during relative motion with respect to the electrical conductor.

[0038] The term "electric connection" in relation to two components means that electric current is transmitted from one component to the other component and / or from the other component to one component, directly or through an electrical conductor arranged between the two components.

[0039] The term "elastically deformable" refers to the ability of a body to deform when subjected to a force or pressure and to return to the body's original condition and shape once the application of such force or pressure ceases.

[0040] The present invention in one or more of its aspects may have at least one of the preferred features described below. Such features may exist individually or in combination with each other, unless explicitly stated otherwise.

[0041] Preferably, the electrical contacts are made in one piece.

[0042] In an alternative embodiment, the electrical contact is made of a plurality of parts, at least one of which is elastically deformable.

[0043] Preferably, each electrical contact comprises a first end fixed relative to said first support and electrically connected to a respective first electrical track and a second end in contact against a respective conductive ring.

[0044] Preferably, the plurality of electrical contacts are arranged radially within the plurality of conductive rings.

[0045] Preferably, the electrical contacts are arranged at least 0.5 mm, preferably at least 0.8 mm and even more preferably at least 1 mm apart from each other.

[0046] Preferably, each electrical contact is arranged at a distance from the axially adjacent electrical contact comprised between 0.5 mm and 1 cm, preferably between 0.8 mm and 8 mm, more preferably between 0.9 mm and 4 mm, for example about 1 mm.

[0047] In an embodiment, said first electrical tracks follow respective paths of equal length.

[0048] Preferably, the first electrical tracks are arranged at least 1 mm apart.

[0049] Preferably, each first electrical track is arranged at a distance from an adjacent first electrical track in a direction perpendicular to the axial direction comprised between 0.2 mm and 1 cm, preferably between 0.3 mm and 5 mm, more preferably between 0.4 mm and 2 mm, for example about 1 mm.

[0050] Preferably, the electrical contacts are arranged in two rows along parallel axial directions.

[0051] Preferably, each electrical contact on a first one of the two rows faces a blank space dividing two axially adjacent connectors on a second one of the two rows in a direction perpendicular to the axial direction.

[0052] The alternating arrangement in two parallel rows increases the mutual distance of the electrical contacts, reducing any mutual electromagnetic interference, while maintaining limited axial obstruction of the slip ring.

[0053] Preferably, the electrical contacts in each row taper from an axially wide portion facing away from the opposing row to an axially narrow portion facing the opposing row.

[0054] Preferably, each electrical contact in one row of electrical contacts extends in a direct direction towards another row of electrical contacts by a length greater than half the distance separating the first ends of electrical contacts of different rows in the same direction.

[0055] Preferably, an ideal line is defined which extends in the axial direction and intercepts the two rows of electrical contacts.

[0056] Preferably, each electrical contact comprises a thin plate.

[0057] Preferably, such a thin plate has a first end corresponding to the first end of the electrical contact and a second end corresponding to the second end of the electrical contact.

[0058] Preferably, the second end of the sheet overlaps the first end of the sheet so as to define a curved portion between the first end and the second end.

[0059] Preferably, a portion of the thin plate extending between the bent portion and the second end is elastically deformed to press against the corresponding conductive ring.

[0060] Preferably, the second end of each thin plate is curved.

[0061] Preferably, the second end of each thin plate is tangent to a portion of the conductive ring in contact therewith.

[0062] Preferably, a first printed circuit board is arranged to extend axially from the first electrical interface within the cavity defined by the conductive ring, the first electrical track being placed on the first printed circuit board.

[0063] Preferably, the first end of the electrical contact is fixed to the first printed circuit board, preferably soldered to the first printed circuit board.

[0064] Preferably, the first printed circuit board is made of a rigid material.

[0065] Preferably, the first support body comprises a cylindrical support surface having an opposite shape to the radial inner surface of the conductive ring and a recess radially spaced apart from the radial inner surface of the conductive ring.

[0066] Preferably, the conductive ring is mounted on a supporting surface of the first supporting body.

[0067] Preferably, the first printed circuit board is accommodated in the recess of the first support body.

[0068] Preferably, the recess accommodates the first printed circuit board, the first electrical tracks and the electrical contacts.

[0069] Preferably, a conductive ring is mounted on the first printed circuit board.

[0070] Preferably, applying pressure on the plurality of electrical contacts to elastically deform the plurality of electrical contacts is actuated by compressing the electrical contacts with a manipulation tool.

[0071] Preferably, the manipulation tool compresses the second end of the electrical contact towards the first end of the electrical contact.

[0072] Preferably, compressing the second end of the electrical contact towards the first end of the electrical contact with a manipulation tool comprises placing the manipulation tool in contact with the second end of the electrical contact and pressing the manipulation tool towards the first support.

[0073] Preferably, arranging a plurality of conductive rings on the first support comprises fitting each conductive ring around the manipulation tool and translating the conductive ring along the manipulation tool until the axial position of the corresponding electrical contact is reached.

[0074] Preferably, compressing the second end of the electrical contact toward the first end of the electrical contact with the manipulation tool comprises arranging at least a portion of the manipulation tool and the second end of the electrical contact within the recess.

[0075] Preferably, fitting of each conductive ring around the manipulation tool and translating the conductive ring along the manipulation tool is actuated while at least a portion of the manipulation tool and the second end of the electrical contact are arranged within the recess.

[0076] Preferably, removing the pressure from the plurality of electrical contacts comprises moving the manipulation tool axially away from a recess. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Other characteristics and advantages of the present description will become more apparent from the following detailed description of a preferred embodiment provided by way of indicative and non-limiting examples, with reference to the accompanying drawings, in which:

[0078] Figure 1 is a perspective view of a slip ring according to the present invention;

[0079] Figure 2 According to different angles Figure 1 A three-dimensional diagram of the slip ring;

[0080] Figure 3 yes Figure 1 A cross-sectional view of a slip ring;

[0081] Figure 4 yes Figure 1 The slip ring and Figure 3 A sectional view orthogonal to a sectional view;

[0082] Figure 5 yes Figure 1 A perspective view of a slip ring with some components removed to highlight other components;

[0083] Figure 6 yes Figure 5 a perspective view of the exploded components shown in ;

[0084] Figure 7 is based on Figure 5 Perspective views of the exploded components shown in FIG.

[0085] Figure 8 yes Figure 1 A top view of the slip ring details;

[0086] Fig. 9 yes Figure 7 Bottom view of the details;

[0087] Fig.10 yes Figure 1 Top view of different details of the slip ring;

[0088] Fig.11 yes Fig.10 A bottom view of the details;

[0089] Fig.12 yes Figure 1 Cross-sectional view of some components of the slip ring during assembly. DETAILED DESCRIPTION

[0090] The slip ring shown in the drawings is denoted by reference numeral 1 .

[0091] The slip ring 1 comprises a first part 10 and a second part 20, the second part 20 being rotatably connected to the first part 10 about a rotation axis R. A rotation coupling member 25 is interposed between the first part 10 and the second part 20, the rotation coupling member being configured to allow them to rotate relative to each other about the rotation axis R. In the illustrated embodiment, the rotation coupling member 25 comprises two concentric bushings 26 that are integral with the first part 10 and the second part 20, respectively.

[0092] The first part 10 includes a first support body 30, which is preferably made of an electrically insulating material (e.g., a plastic material). The first support body 30 extends around the rotation axis R. The first support body 30 includes a base portion 31, on which the rotation coupling member 25 is mounted. The base portion 31 has a side surface 32 extending cylindrically around the rotation axis R and a base surface 33 orthogonal to the rotation axis R. One of the bushings 26 of the rotation coupling member 25 is assembled on the side surface 32. The base portion 31 also includes a housing seat 34 opened at the base surface 33. The housing seat 34 is preferably arranged along the rotation axis R.

[0093] The first support body 30 includes a first support portion 35 protruding from the base portion 31 on the opposite side of the base surface 33 along the rotation axis R. The first support portion 35 includes a cylindrical support surface 35 a centered on the rotation axis R. The support surface 35 a is concentric and has a smaller radius than the outer surface 32 .

[0094] The first support portion 35 includes a recess 36 extending parallel to the rotation axis R. The recess 36 has a bottom wall 37 radially inward relative to the support surface 35a and two side walls 38 extending from the bottom wall 37 to the support surface 35a. The bottom wall 37 is flat and extends parallel to the rotation axis R. The side walls 38 are parallel to each other and orthogonal to the bottom wall 37.

[0095] The first support 30 further comprises an opening 39 extending from the housing seat 34 to the recess 36. The opening 39 is obtained in the base portion 31 to connect the housing seat 34 with the recess 36. The housing seat 34, the opening and the recess 36 are aligned parallel to the axis R of rotation.

[0096] The first part 10 comprises a first printed circuit board 40, which is fixedly held on the first support 30 and arranged parallel to the rotation axis R. The first printed circuit board 40 is inserted into the recess 36 against the bottom wall 37, extends through the opening 39 and engages with the housing seat 34. The first printed circuit board 40 comprises a first portion 41 arranged in the housing seat 34 and a second portion 42 arranged in the opening 39 and in the recess 36. The second portion 42 has an elongated shape parallel to the rotation axis R. The width of the first portion 41 is greater than the width of the second portion 42, the width being measured orthogonally relative to the rotation axis R. Preferably, the first portion 41 is of an opposite shape to the housing seat 34 and the second portion 42 is of an opposite shape to the recess 36, so as to stop the first printed circuit board 40 in the direction of the rotation axis R.

[0097] The first electrical interface 50 is arranged in the housing seat 34, preferably flush with the base surface 33, integral with the first component 10. The first electrical interface 50 is accessible from the outside of the slip ring 1 to connect a first electrical component (not shown) to the first part 10 of the slip ring 1. The first electrical component may be, for example, a twisted pair cable, preferably provided with a multi-pin connector.

[0098] Preferably, the first electrical interface 50 comprises a first multi-pin connector 51, which is configured to receive a corresponding multi-pin connector of the first electrical component. In the illustrated embodiment, the first multi-pin connector 51 is a female Ethernet connector (socket), specifically of the 8p8c type. The first multi-pin connector 51 is soldered to the first printed circuit board 40, in particular to the first portion 41.

[0099] In an alternative embodiment not shown, the first electrical interface 50 may comprise, for example, a region of the first printed circuit board 40 arranged for electrical connection with the first electrical component, for example by soldering.

[0100] A plurality of first electrical tracks 60 are placed on the first printed circuit board 40. Each first electrical track 60 extends from a first end 61 disposed on the first portion 41 electrically connected to the first electrical interface 50 to a second end 62 disposed on the second portion 42 in the recess 36. Each first electrical track 60 is arranged to be electrically connected to a corresponding pin of the first multi-pin connector 51. The first electrical track 60 extends from the housing seat 34 to the recess 36 through the opening 39.

[0101] In alternative embodiments not shown, the first printed circuit board 50 may be integrated in any type of substrate integral with the first support 30 , or may be integral with the first support 30 .

[0102] The first part 10 also includes a plurality of electrical contacts 70 made of an electrically conductive and elastically deformable material. Each electrical contact 70 is electrically connected to the second end 62 of the corresponding first electrical track 60. In the embodiment shown, the electrical contacts 70 are soldered on the first printed circuit board 40, in particular on the second part 42.

[0103] Each electrical contact 70 comprises a thin plate 71 extending from a first end 72 to a second end 73. The first end 72 is arranged in the recess 36 where it is fixedly connected to the printed circuit board 50 at the second end 62 of the corresponding first electrical track 60, preferably by soldering.

[0104] The second end 73 is arranged radially outside the first end 72. The electrical contact 70 is configured so that in the undeformed state, the second end 73 protrudes from the recess 36. In other words, in the undeformed state, the second end 73 protrudes outward from the perimeter defined by the support surface 35a. The second end 73 has a concave profile, wherein the concave surface faces the rotation axis R.

[0105] The thin plate 71 is folded into a U-shape between the first end 72 and the second end 73 so as to form a curved portion 74 between the first end 72 and the second end 73. The curved portion 74 defines an angle between the first end 72 and the second end 73 that is greater than 120°, preferably greater than 150°. In the illustrated embodiment, the curved portion 74 defines an angle of 180°.

[0106] The thin plate 71 is elastically deformable to allow the first end 72 and the second end 73 to approach each other so as to exert a force directed radially away from the rotation axis R on the second end 73. In particular, the thin plate 71 is configured to bend elastically to allow the first end 72 and the second end 73 to approach each other.

[0107] The electrical contacts 70 are arranged in two rows parallel to the rotation axis R. Preferably, the electrical contacts 70 are arranged between the two rows in an axially alternating distribution. In other words, each electrical contact 70 of a given row faces the empty space 70a between two consecutive electrical contacts 70 of the opposite row. The electrical contacts 70 are mounted at a distance of at least 1 mm from each other.

[0108] Each electrical contact 70 is installed so that the bent portion 74 faces the opposite row. Preferably, the electrical contact 70 has a tapered shape from an axially wide portion 75 facing away from the opposite row to an axially narrow portion 76 facing the opposite row. In particular, the axially wide portion 75 corresponds to the first end 73, and the axially narrow portion 76 corresponds to the bent portion 74.

[0109] The two rows of electrical contacts 70 partially interpenetrate each other such that their respective axially narrowed portions 76 are substantially axially aligned with each other.

[0110] A plurality of conductive rings 80 are fixedly mounted on the first support 30. Each conductive ring 80 is made of a conductive material such as copper, brass, aluminum or alloys thereof, and each conductive ring 80 may be coated with a valuable conductive material such as gold or silver.

[0111] The conductive rings 80 are arranged side by side coaxially and parallel to the rotation axis R. The conductive rings 80 have a radial inner surface 81 that is in the opposite cylindrical shape to the support surface 35a (preferably cylindrical). The conductive rings 80 also have a radial outer surface 82 configured to extend along one or more brushes. The radial outer surface 82 includes a circumferential groove 82a, and the corresponding brush slides in the circumferential groove 82a. The conductive ring 80 mounted on the support body 30 is assembled on the first support portion 35.

[0112] A plurality of insulating rings 83 made of insulating material (e.g., plastic) are coaxially mounted on the first support 30 with the plurality of conductive rings 80. The insulating rings 83 are alternated with the conductive rings 80 so that each insulating ring 83 is interposed between two conductive rings 80 to separate and electrically insulate the two conductive rings 80. The insulating rings 83 are thicker than the conductive rings 80 in radial and axial directions.

[0113] In an alternative embodiment not shown, insulating ring 83 may be omitted and conductive rings 80 may be spaced apart from one another such that atmospheric air acts as an electrical insulator therebetween.

[0114] The conductive ring 80 and the insulating ring 83 define side by side an inner cavity into which the first printed circuit board 40, the plurality of first electrical tracks 60, and the plurality of electrical contacts 70 arranged in the recess 36 are inserted.

[0115] The conductive ring 80 and the insulating ring 83 are fixed to the first support 30 by a fixing member 84 configured to compress the conductive ring 80 and the insulating ring 83 along the rotation axis R. In the illustrated embodiment, the fixing member 84 includes a disk 85 having a diameter greater than the diameter of the support surface 35a and a coupling member 86 configured to clamp the disk 85 to the first support 30, such as a screw or a bolt.

[0116] The radial inner surface 81 of each conductive ring 80 is arranged on the recess 36 in contact with the second end 73 of the corresponding electrical contact 70. The conductive ring 80 is electrically connected to the first electrical interface 50 through the electrical contact 70. Both the conductive ring 80 and the electrical contact 70 are integrally mounted to the first support body 30 so that no sliding or other mutual movement occurs during the use of the slip ring 1.

[0117] The second end 73 of each electrical contact 70 is arranged to abut against the radial inner surface 81 of the corresponding conductive ring 80 and is pressed toward the first end 72 by the conductive ring 80. The electrical contact 70 is compressed by the elastic deformation of the bent portion 74. The elastic force 74 applied by the electrical contact 70 maintains the pressure between the second end 73 thereof and the conductive ring 80 and ensures a stable electrical connection between the electrical contact 70 and the conductive ring 80.

[0118] The curvature of the second end 73 of each electrical contact 70 causes the second end 73 to be tangential to the radial inner surface 81 at the contact area so as to reduce electrical contact resistance.

[0119] The second part 20 of the slip ring 1 comprises a second support body 90 rotatably coupled to the first support body 30 by means of a rotation coupling member 25 .

[0120] The second support body 90 has a cup shape extending circumferentially around the rotation axis R. The second support body 90 includes a cylindrical side wall 91 and a flat bottom wall 92 .

[0121] The second support body 90 defines an inner volume 93 and a cylindrical mouth 94 for accessing the inner volume 93 opposite the bottom wall 92. At the mouth 94, the other of the two bushings 26 of the rotation coupling member 25 is fixed.

[0122] The first part 10 of the slip ring 1 is at least partially accommodated in the inner volume 93. Specifically, the first support 35, the electrical contacts 70, and the conductive ring 80 and the insulating ring 83 are accommodated in the inner volume 93. The first printed circuit board 40 and the first electrical track 60 are at least partially accommodated in the inner volume 91.

[0123] The second support body 90 comprises a second support portion 95 protruding from the side wall 91 in the inner volume 93. At the bottom wall 92, the second support body 90 comprises a second opening 96 for accessing the inner volume 93.

[0124] The second part 20 comprises a second printed circuit board 100 which is fixedly held to the second support 90 and arranged in the inner volume 93 parallel to the rotation axis R. The second printed circuit board 100 is held in place by a second support 95. In the embodiment shown, the second printed circuit board 100 has a rectangular shape which is elongated in the direction of the rotation axis R.

[0125] The second electrical interface 110 is arranged in the inner volume 93 facing the second opening 96 , so as to be accessible from outside the slip ring 1 .

[0126] The second electrical interface 110 is configured to electrically connect a second electrical component (not shown) to the second part 20 of the slip ring 1. The second electrical component may for example be a twisted pair cable, preferably provided with a multi-pin connector, for example a male Ethernet connector, in particular of the 8p8c type.

[0127] Preferably, the second electrical interface 110 comprises a second multi-pin connector 111 configured to receive a corresponding multi-pin connector of a second electrical component. In the illustrated embodiment, the second multi-pin connector 111 is a female Ethernet connector (socket), specifically 8p8c type. The second multi-pin connector 111 is soldered on the second printed circuit board 100.

[0128] In an alternative embodiment not shown, the second electrical interface 110 may comprise, for example, a region of the second printed circuit board 100 arranged for electrical connection with the second electrical component by, for example, soldering.

[0129] A plurality of second electrical tracks 120 are placed on the second printed circuit board 100. Each second electrical track 120 is arranged to be electrically connected to a corresponding pin of the second multi-pin connector 111. Each second electrical track 120 extends from a first end 121 electrically connected to the second electrical interface 110 to two second ends 122 arranged near the corresponding conductive ring 80. The second ends 122 and the corresponding conductive ring 80 are arranged in the same plane orthogonal to the rotation axis R.

[0130] The second part 20 also includes a plurality of brushes 130 made of a conductive material (such as copper, brass, aluminum or alloys thereof), which may be coated with a precious conductive material (such as gold or silver). Each brush 130 is electrically connected to the second end 122 of the corresponding second electrical track 120. In the illustrated embodiment, the brushes 130 are soldered to the second printed circuit board 100.

[0131] Each brush 130 comprises a rod 131 which projects from the second printed circuit board 100 towards the corresponding conductive ring 80 and is arranged to be in contact with the corresponding conductive ring 80, the conductive ring 80 being tangential to the rod 131 so that mutual rotation of the first part 10 and the second part 20 causes the brush 130 to slide on the corresponding conductive ring 80. Each brush 130 is oriented to be arranged in a plane orthogonal to the rotation axis R. For each conductive ring 80, there are two brushes 130 which are parallel to each other and arranged on opposite sides of the conductive ring 80.

[0132] The brush 130 is arranged to be electrically connected to the second electrical interface 110 via the second electrical track 120 .

[0133] Therefore, the first electrical interface 50 and the second electrical interface 110 are electrically connected to each other through the first electrical track 60 , the electrical contact 70 , the conductive ring 80 , the brush 130 and the second electrical track 120 in any relative rotation between the first component 10 and the second component 20 .

[0134] To assemble a slip ring 1 of the type described above, a first printed circuit board 40 is arranged, on which a first electrical track 60 is placed. The first electrical interface 50 is preferably arranged at the first end 61 of the first electrical track 60 by soldering each pin of the multi-pin connector 51 to the first end 61 of the corresponding first electrical track 60. Furthermore, the electrical contacts 70 are preferably arranged at the second end 62 of the first electrical track 60 by soldering the first end 72 of each electrical contact 70 to the second end 62 of the corresponding first electrical track 60.

[0135] Then, the first printed circuit board 40, the first electrical tracks 60, the first electrical interface 50 and the electrical contacts 70 are associated with the first support 30. To associate them, the first printed circuit board 40 is inserted into the housing seat 34 so that the first printed circuit board 40 engages with the opening 39 and the recess 36. In particular, the second portion 42 of the first printed circuit board 40 is advanced through the housing seat 34 and the opening 39 until the recess 36 and is arranged against the bottom wall 37, thereby keeping the electrical contacts 70 welded on the second portion 42 facing away from the bottom wall 37. The first portion 41 is advanced until the first electrical interface 50 and the first portion 41 itself are completely housed in the housing seat 34.

[0136] The first printed circuit board 40 is fixed to the first support body 30 , for example, by adhesive or form coupling.

[0137] Then, the electrical contact 70 is elastically deformed so as to compress the second end to the first support body 30, specifically to the bottom wall 37. The electrical contact 70 is deformed so that the second end 73 faces the recess 36 within the perimeter defined by the support surface 35a. The electrical contact 70 is deformed by compressing the second end 73 toward the first end 72 so that the bent portion 74 is elastically bent. Fig.12 The electrical contact 70 is shown before and after elastic deformation.

[0138] In order to deform the electrical contact 70, the manipulation tool 140 (at Fig.12 The first support 30 is shown in cross section in FIG. 1 ) so as to be positioned in contact with the second end 73 and to press the manipulation tool 140 towards the first support 30. Preferably, the manipulation tool 140 is rod-shaped. The manipulation tool 140 is pressed towards the first support 30 so that one end 141 of the manipulation tool 140 radially enters the recess 36 and the manipulation tool 140 itself does not engage the perimeter defined by the support surface 35a.

[0139] When the electrical contacts 70 are in an elastically deformed state, the conductive rings 80 are arranged on the first support 30. Each conductive ring 80 is mounted on the first support 35, contacts the support surface 35a, and slides translationally along the support surface 35a to a predetermined position, at which each conductive ring 80 overlaps the corresponding electrical contact 70. In order to mount the conductive ring 80 on the support surface 35a, the conductive ring 80 is mounted on the manipulation tool 140 (kept under pressure against the electrical contacts 70), and the conductive ring 80 is translated along the manipulation tool 140 until the conductive ring 80 is located at a predetermined position on the first support 35.

[0140] Between each conductive ring 80 and the next conductive ring 80, an insulating ring 83 is arranged on the first support 30. Each insulating ring 83 is mounted on the first support 35, in contact with the support surface 35a, and slides translationally along the support surface 35a until each insulating ring 83 abuts against the previously mounted conductive ring 80, so that the next mounted conductive ring 80 is arranged to abut against the insulating ring 83 on the opposite side. In order to mount the insulating ring 83 on the support surface 35a, the insulating ring 83 is mounted on the manipulation tool 140 (kept under pressure against the electrical contacts 70), and the insulating ring 83 is translated along the manipulation tool 140 until the insulating ring 83 is located at a predetermined position on the first support 35.

[0141] After the conductive ring 80 and the insulating ring 83 are arranged on the first support 30, the electrical contact 70 is released so that the second end 73 is elastically restored against the radial inner surface 81 of the conductive ring 80, so that the electrical contact 70 maintains a sufficient elastic preload to press against the radial inner surface 81 with sufficient force to form a stable, stress-resistant electrical connection of the slip ring 1. The electrical contact 70 is released by pulling the manipulation tool 140 along the recess 36.

[0142] Then, the conductive ring 80 and the insulating ring 83 are locked in place by the fixing member 84 compressing them toward the base portion 31. The conductive ring 80 and the insulating ring 83 are locked in place by clamping the disc-shaped body 85 toward the base portion 31.

[0143] Then, the second printed circuit board 100 is arranged, and the second electrical track 120 is placed on the second printed circuit board 100. The second electrical interface 110 is arranged on the second printed circuit board 100, preferably by soldering each pin of the multi-pin connector 111 to the corresponding second electrical track 120. In addition, the brushes 130 are arranged by soldering each brush 130 to the corresponding second electrical track 120 on the side of the second printed circuit board 100 opposite to the second electrical interface 110.

[0144] Then, the brush 130 is coupled to the conductive ring 80 in a sliding contact manner. To couple the brush 130 to the conductive ring 80, the second printed circuit board 100 is brought closer to the first support body 30 relative to the conductive ring 80 in a radial direction until the brush 130 engages the conductive ring 80 with a predetermined contact force.

[0145] Then, the rotation coupling member 25 is arranged on the first support body 30 and the second support body 90 is assembled. The second support body 90 is assembled so that the mouth 94 engages the rotation coupling member 25 so as to rotatably couple the second support body 90 to the first support body 30 around the rotation axis R. The second support body 90 is also assembled so that the second support portion 95 engages the second printed circuit board 100 and the second electrical interface 110 to fixedly hold them to the second support body 90 itself. The second support body 90 is assembled, and the second opening 96 is provided in front of the second electrical interface 110 to allow access to the second electrical interface 110 from the outside.

[0146] In the embodiment shown, the second support body 90 comprises two separate halves 97 and is assembled by placing each half 97 against the first already assembled component 10 from opposite directions and fixing the two halves to each other.

Claims

1. A slip ring (1), the slip ring (1) include: A first support body (30); a first electrical interface (50) associated with the first support (30) and configured to be electrically connected to a first electrical component; A plurality of conductive rings (80), wherein the plurality of conductive rings (80) are fixedly mounted on the first support body (30); a plurality of first electrical tracks (60), the plurality of first electrical tracks being electrically connected to the first electrical interface (50) and being fixedly mounted on the first support body (30); a plurality of electrical contacts (70), each electrical contact (70) being electrically connected to a respective first electrical track (60) and elastically deforming when the electrical contact (70) abuts against the respective conductive ring (80); a second support body (90) rotatably coupled to the first support body (30) about an axial rotation axis (R); a second electrical interface (110) associated with the second support (90) and configured to be electrically connected to a second electrical component; A plurality of brushes (130) are fixedly mounted to the second support body (90) and electrically connected to the second electrical interface (110), wherein each of the brushes (130) is arranged to be in sliding contact with a corresponding conductive ring (80).

2. The slip ring (1) according to claim 1, in, Each of the electrical contacts (70) comprises a first end (72) fixed relative to the first support (30) and electrically connected to the corresponding first electrical track (60) and a second end (73) in contact with the corresponding conductive ring (80).

3. The slip ring (1) according to claim 1 or 2, in, The plurality of electrical contacts (70) are arranged radially inside the plurality of conductive rings (80).

4. The slip ring (1) according to any one of the preceding claims, in, The electrical contacts (70) are arranged at least 0.5 mm, preferably at least 0.8 mm, even more preferably at least 1 mm apart from each other.

5. Slip ring (1) according to at least one of the preceding claims, in, The electrical contacts (70) are arranged alternately in two parallel axial rows.

6. Slip ring (1) according to at least one of the preceding claims, in, Each of the electrical contacts (70) comprises a thin plate (71) having a first end corresponding to the first end (72) of the electrical contact (70) and a second end corresponding to the second end (73) of the electrical contact (70), the second end of the thin plate (71) overlapping the first end of the thin plate to define a bent portion (74) between the first end and the second end.

7. The slip ring (1) according to claim 6, in, The second end of each of the thin plates (71) is bent and tangential to a portion of the conductive ring (80) that is in contact with the second end of the thin plate (71).

8. Slip ring (1) according to at least one of the preceding claims, in, The first electrical tracks (60) have the same length and a mutual spacing of at least 1 mm.

9. The slip ring (1) according to at least one of the preceding claims, further comprising: include: A first printed circuit board (40) extends axially from the first electrical interface (50) within a cavity defined by the conductive ring (80), the first electrical track (60) being disposed in the printed circuit board (40).

10. The slip ring (1) according to claim 9, in, The first support body (30) includes a cylindrical support surface (35a) having an opposite shape to the radial inner surface (81) of the conductive ring (80) and a recess (36) radially spaced apart from the radial inner surface (81) of the conductive ring (80), the conductive ring (80) being mounted on the support surface (35a) and the first printed circuit board (40) being accommodated in the recess (36).

11. A method for assembling a slip ring (1), include: A first support (30), a first electrical interface (50), a plurality of first electrical tracks (60) and a plurality of electrical contacts (70) are provided, wherein the first electrical interface (50) is configured to be electrically connected to a first electrical component and is associated with the first support (30), the plurality of first electrical tracks (60) are electrically connected to the first electrical interface (50) and extend on the first support (30), and each electrical contact (70) is electrically connected to a corresponding first electrical track (60) and is elastically deformable; Applying pressure to the plurality of electrical contacts (70) to elastically deform the plurality of electrical contacts (70); Arranging a plurality of conductive rings (80) on the first support (30) and removing the pressure from the plurality of electrical contacts (70) so that each electrical contact (70) contacts a corresponding conductive ring (80); A plurality of brushes (130) are coupled to the corresponding conductive rings (80) in sliding contact, wherein the plurality of brushes (130) are electrically connected to a second electrical interface (110) configured to be electrically connected to a second electrical component.

12. The method according to claim 11, in, Applying pressure on the plurality of electrical contacts (70) is achieved by pressing the electrical contacts (70) with a manipulation tool (140), and wherein arranging the plurality of conductive rings (80) on the first support body (30) comprises fitting each conductive ring (80) around the manipulation tool (140) and translating the conductive ring (80) along the manipulation tool (140) until the axial position of the corresponding electrical contact (70) is reached.

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