Technical Field

The present disclosure generally relates to an enclosure. In particular, an enclosure for an electric device, and a method of sealing a through opening of an enclosure, are provided.

Background

An industrial robot may comprise a plurality of joints or axes, such as three to seven joints. At each joint, one member is driven relative to another member by an electric motor. The industrial robot may further comprise a watertight enclosure or connection box connected to each electric motor. Power and signal cables may be led into the enclosures for connection to a respective electric motor.

In order to provide water tightness for the feed-through of the cables into the enclosure, a cable gland may be attached to each cable. The cable glands may then be connected to a sheet metal bracket, for example by screws, which is then connected to the enclosure.

US 5564312 A discloses a cable assembly for an industrial robot comprising power and signal cables, which by means of watertight bushings extend through a watertight connection box connected at each motor unit, such that the respective cable serves all the motor units connected along the cable.

Summary

The assembly of an enclosure comprising cable glands connected to a sheet metal bracket is complicated and time consuming. Moreover, the cable glands need to be relatively large compared to the enclosure. This adds size to the enclosure. In case the cable glands are connected by means of screws, these screws need to be accessed by a tool, which may further add size to the enclosure. Cable glands are also relatively expensive.

One object of the present disclosure is to provide an enclosure for an electric device, which enclosure has a good sealing performance. A further object of the present disclosure is to provide an enclosure for an electric device, which enclosure has a simple design, for example requiring few parts.

A still further object of the present disclosure is to provide an enclosure for an electric device, which enclosure has a compact design. A still further object of the present disclosure is to provide an enclosure for an electric device, which enclosure has a cost-effective design.

A still further object of the present disclosure is to provide an enclosure for an electric device, which enclosure enables simple assembly.

A still further object of the present disclosure is to provide an enclosure for an electric device, which enclosure enables simple manufacture.

A still further object of the present disclosure is to provide an enclosure for an electric device, which enclosure solves several or all of the foregoing objects in combination.

A still further object of the present disclosure is to provide a method of sealing a through opening of an enclosure for an electric device, which method solves one, several or all of the foregoing objects.

According to one aspect, there is provided an enclosure for an electric device, the enclosure comprising a first enclosure part; a second enclosure part connected to the first enclosure part; a space arranged between the first enclosure part and the second enclosure part; a through opening into the space, the through opening being defined by the first enclosure part and the second enclosure part; a cable arrangement comprising at least one cable, the cable arrangement extending through the through opening into the space for connection to the electric device; a flexible sealing device enclosing the cable arrangement and sealing the through opening; wherein the sealing device is compressed by the first enclosure part and the second enclosure part to establish the sealing of the through opening.

The enclosure thus comprises a feed-through solution for cabling into the enclosure. By providing a flexible sealing device enclosing the cable arrangement, and by compressing the sealing device by the first enclosure part and the second enclosure part, the cable arrangement can be sealingly fed into the enclosure in a simple manner. Moreover, by providing a flexible sealing device enclosing the cable arrangement, which sealing device is compressed by the first enclosure part and the second enclosure part, no gaskets are needed and no fasteners dedicated to the sealing are needed. The enclosure thereby has a good sealing performance with a compact and simple design.

The sealing device may be arranged to enclose the cable arrangement at a remote site, e.g. at supplier level. This facilitates subsequent assembly of the enclosure. The cable arrangement prepared with the sealing device may be arranged in a through opening section of the first enclosure part, i.e. such that the sealing device is aligned with the through opening section. The second enclosure part may then be connected to the first enclosure part such that the sealing device is compressed and establishes the sealing of the through opening.

The enclosure may be a connection box. The enclosure may be configured to be connected to an electric motor of an industrial robot. In this case, the electric device may be associated with the electric motor. The electric device may for example be an electric connection device of the electric motor. The first enclosure part may comprise an opening for receiving the electric device. An axial seal, such as a gasket, may be provided between the first enclosure part and the electric motor. The first enclosure part may be screwed onto the electric motor. Once the enclosure is connected to the electric motor, the enclosure provides protection against dust and water. According to one variant, the enclosure complies with the IP67 standard of the International Protection (IP) rating system which requires that the enclosure is dust proof and that the enclosure prevents the entry of water into the space if immersed in room temperature water to a depth of 1 meter for 30 minutes.

The second enclosure part may be connected to the first enclosure part by means of fasteners or a snap-fit connection. The first enclosure part and the second enclosure part may be connected substantially along, or along, a mating plane. In this case, the enclosure enables a particularly compact size in a direction perpendicular to the mating plane.

The first enclosure part and the second enclosure part may be a first enclosure half and a second enclosure half, respectively. The first enclosure part may comprise side walls and the second enclosure part may be a cover.

The cable arrangement may comprise one or more power cables and/or one or more signal cables. The space may be configured to accommodate the electric device. According to one variant, the enclosure also comprises the electric device.

A size of a circumferential profile of the through opening may be smaller than a size of a corresponding circumferential profile of the sealing device prior to compressing the sealing device. Thus, there may be an offset in size between the sealing device and the through opening. The offset may be substantially evenly distributed, or evenly distributed. With corresponding circumferential profile of the sealing device is meant a profile of the sealing device that is aligned with the through opening. A total length of the circumference of the through opening may be smaller than a total length of the corresponding circumference of the sealing device prior to compressing the sealing device.

A size of a circumferential profile may be a circumferential length of the circumferential profile, e.g. in a plane substantially perpendicular to, or perpendicular to, a longitudinal axis of a cable of the cable arrangement. When connecting the second enclosure part to the first enclosure part, the connection force applied to the second enclosure part (e.g. by fasteners) will cause the sealing device to swell in the through opening and create a sealing effect.

The size of the circumferential profile of the sealing device may be at least 2% larger, such as at least 3% larger, than the size of the circumferential profile of the through opening prior to compressing the sealing device.

A shape of the circumferential profile of the sealing device may substantially correspond to, or correspond to, a shape of the circumferential profile of the through opening. The through opening may be of various shapes. According to one variant, the sealing device comprises a flat sealing device surface and the second enclosure part comprises at least one flat enclosure part surface. In this case, the flat sealing device surface may mate with the at least one flat enclosure part surface. The second enclosure part may comprise two flat enclosure part surfaces and an intermediate groove. An axial seal may be received in the groove. In this way, the axial seal can be pressed directly against the sealing device.

The through opening section of the first enclosure part may comprise a circular portion associated with each cable. For example, the through opening section may comprise a relatively large circular portion associated with a relatively large cable, and a relatively small circular portion associated with a relatively small cable. The relatively large circular portion may be joined with the relatively small circular portion. Each circular portion may for example have an angular extension of 90° to 180 ⁰ .

The sealing device may be compressed substantially evenly, or evenly, in all directions. Alternatively, or in addition, the sealing device may be movable relative to the cable arrangement, prior to compressing the sealing device, by means of a force of less than too N, such as less than 50 N. The sealing device can thereby be manually pulled or pushed relative to the cable arrangement, i.e. along a longitudinal axis of the one or more cables. This further facilitates assembly. Moreover, if the sealing device does not need to be rigidly fixed to the cable arrangement prior to compressing the sealing device, manufacture is further facilitated.

The sealing device may however be arranged to resist movements relative to the cable arrangement, for example when being subjected to forces of less than 20 N, such as less than 10 N. In this way, the sealing device can withstand some minor forces without being displaced relative to the cable arrangement.

The cable arrangement may comprise a first cable and a second cable. In this case, a thickness of the sealing device between the first enclosure part and the first cable, and a thickness of the sealing device between the first enclosure part and the second cable, may be substantially the same. The first cable and the second cable may be arranged substantially parallel, or parallel, through the sealing device. When the cable arrangement comprises a plurality of cables, the cable arrangement may be referred to as a cable harness. The first cable and the second cable may be of different circumferential sizes. The cable arrangement may comprise only one cable or more than two cables.

The sealing device may be compressed by the first enclosure part and the second enclosure part to establish a sealing between the sealing device and the cable arrangement. Thus, prior to installing the cable arrangement with the sealing device, there may be some play between the sealing device and the cable arrangement. This enables manufacturing tolerances between the sealing device and the cable arrangement to be relaxed.

The enclosure may further comprise an axial seal arranged between the first enclosure part and the second enclosure part. In this case, the axial seal may lie in a plane, and the axial seal may be mainly compressed in a direction normal to the plane. Thus, the axial seal may be compressed in a direction along which the second enclosure part is connected to the first enclosure part. The axial seal may be a gasket or an O-ring. The axial seal may be integrated in the second enclosure part. Alternatively, or in addition, the axial seal may be a dispensed seal.

The axial seal may enclose the space. Alternatively, or in addition, the axial seal and the sealing device may be integrally formed. For example, the axial seal and the sealing device may be manufactured in one piece in a joint molding process.

The axial seal may be pressed against the sealing device by means of the second enclosure part. The sealing device may be molded. For example, the sealing device may be molded around the cable arrangement at a remote site, e.g. at supplier level. In case the sealing device is molded, there may be no chemical bonding between the sealing device and the cable arrangement.

The sealing device may be a grommet. For example, the grommet may be provided around the cable arrangement at a remote side, e.g. at supplier level. The one or more cables of the cable arrangement may be manually forced through the grommet prior to assembly.

The sealing device may be made of an elastomer material and/or a polymer material. The sealing device may for example be made of elastomeric polyurethane (PUR) or ethylene propylene diene monomer rubber (EPDM).

According to a further aspect, there is provided an industrial robot comprising an electric motor, and an enclosure according to the present disclosure connected to the electric motor.

According to a further aspect, there is provided a method of sealing a through opening of an enclosure for an electric device, the method comprising providing an enclosure comprising a first enclosure part and a second enclosure part, the first enclosure part comprising a through opening section; providing a cable arrangement comprising at least one cable; providing a flexible sealing device enclosing the cable arrangement; arranging the sealing device in the through opening section such that the cable arrangement extends through the through opening section; connecting the second enclosure part to the first enclosure part such that a space is provided between the first enclosure part and the second enclosure part, such that a through opening into the space comprising the through opening section is defined by the first enclosure part and the second enclosure part, and such that the sealing device is compressed by the first enclosure part and the second enclosure part to establish a sealing of the through opening. The method may employ an enclosure of any type according to the present disclosure.

Brief Description of the Drawings

Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the drawings, wherein:

Fig. l: schematically represents a perspective view of an industrial robot comprising a plurality of electric motors and enclosures;

Fig. 2: schematically represents a perspective view of one of the enclosures in Fig. l;

Fig. 3: schematically represents a perspective view of a sealing device of the enclosure;

Fig. 4: schematically represents a bottom view of the sealing device;

Fig. 5: schematically represents a front view of the sealing device;

Fig. 6: schematically represents a partial perspective top view of a first enclosure part of the enclosure;

Fig. 7: schematically represents a partial perspective bottom view of a second enclosure part of the enclosure;

Fig. 8: schematically represents a front view of the enclosure;

Fig. 9: schematically represents a partial cross-sectional front view of the enclosure; and

Fig. 10: schematically represents a perspective partial view of the enclosure. Detailed Description

In the following, an enclosure for an electric device, and a method of sealing a through opening of an enclosure, will be described. The same or similar reference numerals will be used to denote the same or similar structural features.

Fig. l schematically represents a perspective view of an industrial robot 10. The industrial robot io comprises a manipulator having a plurality of joints. The industrial robot io comprises an electric motor 12 associated with each joint. At each joint, one member is driven relative to another member by means of an electric motor 12. In Fig. 1, two external electric motors 12 can be seen. In this example, some electric motors are provided inside the manipulator.

The industrial robot 10 further comprises a plurality of enclosures 14. Each enclosure 14 is connected to an associated electric motor 12. Each enclosure 14 is here exemplified as a connection box. The enclosures 14 are watertight and protects against ingress of water and dust into the electric motor 12.

Fig. 2 schematically represents a perspective view of one of the enclosures 14 in Fig. 1. The enclosure 14 comprises a first enclosure part 16 and a second enclosure part 18. The second enclosure part 18 is connected to the first enclosure part 16, in this example by screws (not shown).

The enclosure 14 comprises a through opening 20. The through opening 20 is defined by the first enclosure part 16 and the second enclosure part 18 in the illustrated closed state of the enclosure 14.

The enclosure 14 further comprises a cable arrangement 22. The cable arrangement 22 of this example comprises a first cable 24 and a second cable 26. The cables 24, 26 extend through the through opening 20 and into a space between the first enclosure part 16 and the second enclosure part 18. Inside the space, the cables 24, 26 can be connected to an electric device. The enclosure 14 further comprises a flexible sealing device 28. The sealing device 28 encloses the cable arrangement 22. When the second enclosure part 18 is connected to the first enclosure part 16, the sealing device 28 is compressed by the connection force of the second enclosure part 18 to the first enclosure part 16. In this example, the compression of the sealing device 28 establishes a seal between the sealing device 28 and the through opening 20, and establishes a seal between the sealing device 28 and the cable arrangement 22. Prior to connecting the second enclosure part 18 to the first enclosure part 16, the sealing device 28 of this example does neither seal to the through opening 20 nor to the cable arrangement 22.

In this example, the first enclosure part 16 comprises a plurality of side walls 30 and the second enclosure part 18 is exemplified as a cover. The second enclosure part 18 is connected to the first enclosure part 16 in a closing direction 42. The closing direction 42 may also be referred to as an axial direction of the enclosure 14. The first enclosure part 16 and the second enclosure part 18 are connected along a mating plane. In this example, the mating plane is perpendicular to the closing direction 42.

The first cable 24 may for example be a power cable for the electric motor 12 and the second cable 26 may for example be a signal cable for the electric motor 12. As shown in Fig. 2, the cables 24, 26 extend in parallel through the sealing device 28. Moreover, the cables 24, 26 are circular and the first cable 24 is larger than the second cable 26. The sealing device 28 of this example is molded in one piece, e.g. of PUR.

Fig. 3 schematically represents a perspective view of the sealing device 28, Fig. 4 schematically represents a bottom view of the sealing device 28, and Fig. 5 schematically represents a front view of the sealing device 28. With collective reference to Figs. 3 to 5, the sealing device 28 comprises a first through hole 44 and a second through hole 46. The first through hole 44 is configured to receive the first cable 24 and the second through hole 46 is configured to receive the second cable 26. The first through hole 44 is larger than the second through hole 46. Moreover, the through holes 44, 46 are circular.

The sealing device 28 further comprises a flat sealing device surface 48. The sealing device surface 48 is parallel with longitudinal axes of the through holes 44, 46. In this example, the sealing device 28 comprises an interiorly protruding section 50, an exteriorly protruding section 52, and an intermediate section 54 between the interiorly protruding section 50 and the exteriorly protruding section 52. The sealing device surface 48 of this example is provided in the intermediate section 54. In the mounted state of the enclosure 14, the interiorly protruding section 50 protrudes from the through opening 20 into the space, the exteriorly protruding section 52 protrudes exteriorly from the through opening 20 to the exterior of the enclosure 14, and the intermediate section 54 is aligned with the through opening 20. Fig. 6 schematically represents a partial perspective top view of the first enclosure part 16. In Fig. 6, a part of the space 56 between the first enclosure part 16 and the second enclosure part 18 can be seen.

The first enclosure part 16 comprises a through opening section 58. The through opening section 58 forms the through opening 20 together with the second enclosure part 18 when the second enclosure part 18 is connected to the first enclosure part 16.

As shown in Fig. 6, the through opening section 58 of this example comprises a first circular portion 60 and a second circular portion 62. The first circular portion 60 is larger than the second circular portion 62. The first circular portion 60 is associated with the first cable 24 and the second circular portion 62 is associated with the second cable 26.

The first circular portion 60 is joined with the second circular portion 62. In this example, an angular extension of the first circular portion 60 is approximately 130° and an angular extension of the second circular portion 62 is approximately 8o°. Fig. 7 schematically represents a partial perspective bottom view of the second enclosure part 18. In Fig. 7, an axial seal 64 of the enclosure 14 can be seen. When the enclosure 14 is assembled, the axial seal 64 is arranged to seal along the mating plane between the first enclosure part 16 and the second enclosure part 18. Moreover, the axial seal 64 is mainly compressed in the closing direction 42 when the second enclosure part 18 is connected to the first enclosure part 16.

The axial seal 64 of this example is a gasket. When the enclosure 14 is assembled, the axial seal 64 encloses the space 56. Also the axial seal 64 may be molded in one piece, e.g. of PUR.

The second enclosure part 18 of this example comprises a two flat enclosure part surfaces 66 and a groove 68 between the enclosure part surfaces 66. The axial seal 64 is received in the groove 68. In the uncompressed state of the axial seal 64 in Fig. 7, the axial seal 64 protrudes out from the groove 68. Fig. 8 schematically represents a front view of the enclosure 14. Fig. 9 schematically represents a partial cross-sectional front view of the enclosure 14 with the cable arrangement 22 removed. In Fig. 9, the sealing device 28 and the axial seal 64 are illustrated in uncompressed states.

As shown in Fig. 9, there is an offset 70 in size between the sealing device 28 and the through opening 20. Thus, the sealing device 28 is larger than the through opening 20. A size of a circumferential profile of the through opening 20 is smaller than a size of a corresponding circumferential profile, i.e. of the intermediate section 54, of the sealing device 28 prior to compressing the sealing device 28. The offset 70 is evenly distributed around the through opening 20. In this example, the circumferential profile of the sealing device 28 is approximately 2% larger than the corresponding circumferential profile of the through opening 20. Furthermore, a total length of the circumference of the sealing device 28 is approximately 2% larger than the corresponding total length of the circumference of the through opening 20. A shape of the circumferential profile of the sealing device 28 corresponds to a shape of the corresponding circumferential profile of the through opening 20. A thickness of the sealing device 28 is substantially uniform along the first circular portion 60 and the second circular portion 62, despite the first cable 24 being larger than the second cable 26.

As further shown in Fig. 9, there is an offset 72 in size between the axial seal 64 and the groove 68. Thus, the axial seal 64 is larger than the groove 68 and protrudes from the groove 68.

As can be gathered from Fig. 9, the axial seal 64 is pressed against the sealing device surface 48 of the sealing device 28 by means of the second enclosure part 18.

Fig. 10 schematically represents a perspective partial view of the enclosure 14. In Fig. 10, an electric device 74, here exemplified as an electric connection device of the electric motor 12, is accommodated within the space 56. The through opening 20 extends into the space 56. Fig. 10 further shows the contact between the axial seal 64 and the sealing device surface 48 of the sealing device 28.

In the following, one specific example of assembling the enclosure 14 and for sealingly closing the through opening 20 will be described. The sealing device 28 may be arranged to enclose the cable arrangement 22 at a remote site by means of molding, e.g. at supplier level.

After molding of the sealing device 28, the sealing device 28 can be manually pulled along the cable arrangement 22 with manual force (e.g. by means of a force less than too N). However, the sealing device 28 can resist certain forces (e.g. less than 20 N, such as less than 10 N) along the cable arrangement 22, for example gravital forces in case the cable arrangement 22 is vertically oriented.

A gasket is provided between the first enclosure part 16 and the electric motor 12. The electric device 74 enter the space 56 through a bottom opening of the first enclosure part 16 when positioning the first enclosure part 16 relative to the electric motor 12. The first enclosure part 16 is then screwed onto the electric motor 12 such that the gasket is compressed.

The sealing device 28 may then be positioned in the through opening section 58 such that the cable arrangement 22 extends through the through opening section 58. In connection with this step, the sealing device 28 may optionally be adjusted along the cable arrangement 22 in order to extend or reduce a length of the cable arrangement 22 inside the space 56.

When the sealing device 28 is aligned with the through opening section 58, the sealing device 28 is substantially uncompressed and thereby extends out from the through opening section 58 (in the axial direction). The axial seal 64 may have been previously fastened to the second enclosure part 18, for example by gluing. This fastening may be made at a remote site, e.g. at supplier level. When connecting the second enclosure part 18 to the first enclosure part 16, the through opening 20 into the space 56 is defined by the first enclosure part 16 and the second enclosure part 18. Moreover, the axial seal 64 becomes positioned in the mating plane surrounding the space 56. The connection force applied to the second enclosure part 18 (here by screws) will cause the sealing device 28 to be pushed down into the through opening section 58.

The sealing device 28 is further compressed substantially evenly in all directions within the through opening 20. A sealing effect is thereby created both between the sealing device 28 and the through opening 20, and between the sealing device 28 and the cables 24, 26 of the cable arrangement 22. The enclosure 14 now provides protection against dust and water.

While the present disclosure has been described with reference to exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. For example, it will be appreciated that the dimensions of the parts may be varied as needed. Accordingly, it is intended that the present invention may be limited only by the scope of the claims appended hereto.