Enclosed drive having an electric motor

Abstract

The present invention relates to an enclosed drive (10) having an electric motor (12), which has an output shaft (14). According to the invention, the entire electric motor (12) and at least some parts of the output shaft (14) are arranged in an enclosed casing (16). The output shaft (14) along its axis of rotation is axially aligned with a shaft coupling (18) and is connected thereto. The shaft coupling (18) extends outwards through an opening (20) in the casing (16), and a flameproof gap (22) is formed between the shaft coupling (18) and the casing (16).

Description

[0001] P2024,1077 WO N / P23-1594WO01 August 22, 2025

[0002] - 1 -

[0003] Encapsulated drive with an electric motor

[0004] The present invention relates to an encapsulated drive with an electric motor which has an output shaft.

[0005] For various applications, encapsulated electric motor drives are required. When operating in environments where explosive gases or gas mixtures may be present, encapsulation prevents such gases from entering the drive. In the event that a gas or gas mixture nevertheless accumulates within the encapsulated drive, the encapsulation must ensure that, if the gas is ignited by a spark, the encapsulation and all seals and penetrations will withstand the resulting explosion. This prevents the explosion from spreading to the surrounding gas mixture.

[0006] Well-known encapsulated drives require special electric motors, which are complex to manufacture and therefore expensive.

[0007] It is therefore the object of the present invention to create an encapsulated drive in which the manufacturing costs are reduced.

[0008] This problem is solved by the subject matter of the independent patent claim.

[0009] According to the invention, the electric motor is completely and the output shaft is at least partially arranged in an encapsulated housing. The output shaft is axially aligned with and connected to a shaft coupling along its axis of rotation. At least one section of the shaft coupling extends to the outside through an opening in the housing, and a flameproof ignition gap is formed between the shaft coupling and the housing.

[0010] Such an encapsulated drive according to the present invention offers the advantage that a normal industrial motor can be transformed by encapsulating the housing with this P2024,1077 WO N / P23-1594WO01 22 August 2025

[0011] - 2 - can be joined together with an explosion-proof drive of the type of ignition protection EX-d.

[0012] In rotating machines, such a shaft bushing from the interior of an EX-d enclosure is subject to very high requirements (tight tolerances, etc.) for the sealing gap (according to DIN 60079-1). The present invention provides a flameproof cylindrical connection using a simple shaft coupling. The installation of the electric motor in a comparatively easy-to-manufacture EX-d enclosure enables the use of standard industrial motors in EX applications. This simple arrangement offers a very cost-effective solution, particularly for low-power and / or low-speed applications where no maintenance is required during the service life.

[0013] Preferred embodiments are set out in the dependent claims.

[0014] Preferably, the shaft coupling is rotatably mounted on the housing by means of at least one bearing, optionally with a first and a second bearing arranged offset from each other along the axis of rotation. Using only one bearing is a simpler solution. The precise alignment of the output shaft, and consequently of the shaft coupling in the housing, defines the standard-compliant design of the ignition gap. Adjustment screws for the electric motor can be provided for this purpose. The use of two bearings simplifies the standard-compliant design of the ignition gap. This is particularly advantageous if the electric motor manufacturer does not provide specifications regarding the alignment and bearing arrangement of the output shaft.

[0015] Preferably, the shaft coupling is rotationally symmetrical and has a radially oriented flange. Optionally, the two bearings can be arranged on opposite sides of the flange.

[0016] The first bearing is preferably arranged radially around the shaft coupling between the side of the flange facing away from the electric motor and an end section of the housing. P2024,1077 WO N / P23-1594WO01 22 August 2025

[0017] - 3 -

[0018] The optional second bearing can also be arranged radially around the shaft coupling between the side of the flange facing the electric motor and the electric motor.

[0019] A particularly preferred embodiment of the invention is one in which the ignition protection gap is formed between the housing and an outwardly facing end surface of the flange.

[0020] The housing can have an end cover that incorporates the housing opening, and preferably a cup-shaped bearing sleeve with a further opening in the base of the bearing sleeve is arranged within this cover. The base of the bearing sleeve then protrudes from the opening in the end cover, and the shaft coupling from the further opening of the bearing sleeve. Providing such a bearing sleeve offers the advantage that a particularly stiff and wear-resistant material, such as a metal, can be used for mounting the bearings. Other sections of the housing can thus be injection-molded more cost-effectively and easily from a (softer) plastic. Conversely, if the housing is made of a metal, for example, aluminum, a separate bearing sleeve can be omitted.

[0021] Preferably, the end surface of the flange is provided that the inner surface of the bearing sleeve forms the (first) ignition protection gap.

[0022] The end cover preferably forms a second ignition protection gap with the housing, and further preferably an outer side of the cup-shaped bearing sleeve with the opening forms a third ignition protection gap.

[0023] Providing ignition protection gaps in all openings, penetrations and joints of housing parts ensures the explosion protection of the housing.

[0024] Preferably, the bearing or bearings – if multiple bearings are provided – are arranged within the bearing sleeve. P2024,1077 WO N / P23-1594WO01 22 August 2025

[0025] - 4 -

[0026] The end cover and the bearing sleeve can also be formed in one piece. This will be the case, in particular, if the one-piece design is to be formed from a single metal.

[0027] A fourth ignition protection gap is preferably provided between the shaft coupling and the output shaft.

[0028] At least two, preferably three, motor mounting and / or adjustment screws can be provided on the housing to secure the electric motor against the at least one bearing and / or to adjust the ignition gap. This offers the advantage that the standards for ignition gaps can be met even if, for example, only one bearing is used.

[0029] A closable filling opening can be provided on the housing for filling the housing with an explosion suppressant. The filling opening can preferably be closed with a screw, which forms a fifth ignition-protection gap with the housing.

[0030] In an alternative embodiment of the present invention, the (first) ignition protection gap is formed between the opening of the housing or between a housing end that forms the opening of the housing and a section of the shaft coupling, which is arranged on a side of the bearing facing away from the electric motor. A separate housing end offers the advantage that a different material (e.g., a metal sleeve) can be used here as well than for other sections of the housing.

[0031] Here too, at least one bearing, or preferably two bearings, can be provided, which are arranged within a bearing sleeve that connects to the housing end in the direction of the electric motor.

[0032] Alternatively, the housing can be made of metal, and the ignition-protection gap can be formed between the housing opening and the shaft coupling. The bearing(s) can then be arranged directly between the housing and a flange of the shaft coupling. P2024,1077 WO N / P23-1594WO01 22 August 2025

[0033] - 5 -

[0034] The invention will now be explained in more detail by way of example with reference to the attached figure.

[0035] This shows:

[0036] Figs. 1 to 3 show a first embodiment of a drive according to the invention; and

[0037] Figures 4 to 6 show a second embodiment of a device according to the invention.

[0038] Drive.

[0039] Figures 1 to 6 show two alternative embodiments of an encapsulated drive 10 according to the invention, comprising an electric motor 12 and an output shaft 14. Figures 1 and 4 show these two embodiments in an exploded view, Figures 2 and 5 in a cross-sectional view, and Figures 3 and 6 in a top view in the assembled state.

[0040] In both alternative embodiments of the invention, the drive 10 includes an electric motor 12 with an output shaft 14. The electric motor 12 is completely and the output shaft 14 partially enclosed in a housing 16, which is designed to be explosion-proof. Explosion-proof enclosure is understood to mean a flameproof enclosure in which all necessary penetrations, for example for electrical cables for the electric motor, are designed to be ignition-proof.

[0041] The output shaft 14 is axially aligned with and connected to a shaft coupling 18 along its axis of rotation. The connection between the output shaft 14 and the shaft coupling 18 is designed by means of a shaft coupling fastening screw 54 (e.g., a setscrew) such that torques from the output shaft 14 can be transmitted to the shaft coupling 18.

[0042] In both embodiments, the shaft coupling 18 is guided to the outside through an opening 20 in the housing 16. A flameproof ignition gap 22 is formed between the shaft coupling 18 and the housing 16. P2024,1077 WO N / P23-1594WO01 August 22, 2025

[0043] - 6 -

[0044] In both embodiments, at least one first bearing 26 and optionally a second bearing 28 are provided for supporting the shaft coupling 18 in the housing 16. Both bearings 26 and 28 are arranged radially around the shaft coupling 18 so that it is rotatably mounted within the housing 16. A flange 30 is arranged on the shaft coupling 18, and the two bearings 26 and 28 are mounted offset from each other along the axis of rotation. Both bearings 26 and 28 are arranged on opposite sides of the flange 30. The first bearing 26 is arranged radially around the shaft coupling 18 between the side of the flange 30 facing away from the electric motor 12 and an end cover 32 of the housing 16. The second bearing 28 is arranged opposite the first bearing 26 on the other side of the flange 30, and thus on the side facing the electric motor 12.

[0045] In the embodiment of Figs. 1 to 3, the ignition protection gap 22 is formed between the housing 16 and an outwardly facing end surface 24 of the flange.

[0046] In the first embodiment according to Figures 1 to 3, the housing 16 also has an end cover 32 which includes the opening 20 of the housing 16. In this exemplary embodiment of the invention, a cup-shaped bearing sleeve 34 is provided within the opening 20 of the housing, with a further opening 36 in a base of the bearing sleeve 34. Providing a separate bearing sleeve 34 offers the advantage that the housing 16 can be largely made of a plastic material, and the bearing sleeve 34 can be made of a metal in a more rigid and wear-resistant form. By providing such a bearing sleeve 34, the two bearings 26 and 28 are permanently and precisely arranged within the housing 16, thus ensuring a consistently accurate adjustment of the ignition gap 22.This is important because any change in the position and orientation of the two bearings 26 and 28 can lead to a failure to meet the relevant standards for the design of the ignition protection gap 22 and may result in an increased risk of explosion. P2024,1077 WO N / P23-1594WO01 22 August 2025.

[0047] - 7 -

[0048] Alternatively, it can also be provided that the housing 16 is made entirely of a metal material, so that the provision of a separate bearing sleeve 34 is not necessary.

[0049] In order to ensure the explosion-proof encapsulation of the entire housing, all other openings and gaps on the housing 16 must also be designed to be explosion-proof and flameproof.

[0050] In the first embodiment shown in Figures 1 to 3, a filling opening 46 is provided on the housing, which is designed to be closed with a screw 50. This filling opening 46 serves to allow cavities within the housing 16 to be filled with an explosion-reducing agent. Such explosion-reducing agents can be suitable gases or solids that prevent or suppress an explosion of any gases that may have entered the housing. For example, such agents can reduce the flame temperature or propagation speed, or the turbulence of explosive gases within the housing. The free volume within the housing, which could be filled by intruding gases, can also be reduced in this way. A further ignition-protection gap 48 is provided at the filling opening 46, formed between the screw 50 and the housing 16.The filling opening 46 is arranged on an end cover 32 of the housing 16, which closes off the housing 16 and carries the bearing sleeve 34. A protective gap 38 is also provided between this end cover 32 and the rest of the housing 16.

[0051] Since, in the embodiment shown in Figures 1 to 3, the bearing sleeve 34 is arranged in the opening 36 of the end cover 32, a further ignition protection gap 40 is also provided between the bearing sleeve 34 and the end cover 32. An additional ignition protection gap 42 is also arranged between the output shaft 14 and the shaft coupling 18, as well as between adjusting screws 44 (ignition protection gap 58) and a base of the housing 16. These three adjusting screws 44 serve to fix and adjust the electric motor 12 so that, in particular, the ignition protection gap 22 is designed in accordance with standards. The ignition protection gap 22 is the most critical of all the ignition protection gaps, as it is located between a rotating component in the form of P2024,1077 WO N / P23-1594WO01 22 August 2025

[0052] - 8 - the shaft coupling 18 and a fixed component in the form of the bearing sleeve 34.

[0053] In the embodiment shown in Figures 1 to 4, four fastening screws 52 are provided for securing the end cover 32. These screws extend through the end cover 32 to corresponding threads in a main part of the housing 16. The end cover 32 also has mounting inserts 53, which serve to mount the drive 10 at a point of use. Such mounting inserts 53 are also provided on the housing 16 shown in Figures 4 to 6.

[0054] For the supply of electrical power, a flameproof cable gland 56 is provided in each of the embodiments shown in Figs. 1 to 6.

[0055] In Figures 2 and 5, a pulley 60 is also mounted on the shaft coupling 18, which can, for example, form a frictional or positive-locking connection to a belt drive. The pulley 60 is secured against rotation or falling off by a fastening screw 70.

[0056] In the embodiment shown in Figures 4 to 6, a drive 10 is presented which, compared to the drive 10 of Figures 1 to 3, can be implemented with a reduced number of ignition protection gaps. As in the embodiment shown in Figures 1 to 4, the first ignition protection gap 22 is provided between an opening 20 in the housing 16 and the shaft coupling 18. In the embodiment shown in Figures 4 to 6, the opening 20 is formed by a housing end cap 62, which in this embodiment is provided as an optional element of the housing 16. Similar to the bearing sleeve 34 of Figures 4 to 6, this housing end cap 62 can be made of a metallic material, and further sections of the housing 16 can be made of a plastic. This ensures a corresponding stability of the housing end cap 62 and the bearing sleeve 34.

[0057] In addition to the ignition protection gap 22, a further ignition protection gap 66 is provided at the housing end 62 between the housing end 62 and the further housing 16, so that with two ignition protection gaps 22 and 66 the area of ​​the drive 10 around the shaft coupling 18 is completely explosion-proof and P2024,1077 WO N / P23-1594WO01 22 August 2025

[0058] - 9 - is designed to be flame-resistant. Naturally, the cable gland 56 is also designed to be flame-resistant, as in the embodiment shown in Figures 1 to 3.

[0059] In the embodiment of Figs. 4 to 5, the housing 16 is not closed by an end cover 32 as in the embodiment of Figs. 1 to 3, but on the side opposite the opening 20 with a cover 68, wherein a flameproof ignition protection gap is again provided between the cover 68 and the remaining sections of the housing 16.

[0060] In the embodiment shown in Figures 1 to 3, the electric motor 12 is inserted into the open housing 16 from the front, and then the end cover 32 is fitted. In the embodiment shown in Figures 3 to 6, the electric motor 12 is inserted into the open housing 16 from the rear, and then the cover 68 is fitted.

[0061] In the embodiment of Figs. 4 to 6, a motor mount 64 is arranged inside the housing 16, to which the motor 12 is attached with four motor mounting screws 72.

[0062] P2024,1077 WO N / P23-1594WO01 August 22, 2025

[0063] - 10 -

[0064] Reference symbol list

[0065] 10 Drive

[0066] 12 Electric motor

[0067] 14 Output shaft

[0068] 16 cases

[0069] 18 Shaft coupling

[0070] 20 Opening

[0071] 22 Ignition protection gap

[0072] 24 End area of ​​30

[0073] 26 first camp

[0074] 28 second camp

[0075] 30 flange

[0076] 32 End cover

[0077] 34 Bearing sleeve (optional)

[0078] 36 Opening

[0079] 38 Ignition protection gap

[0080] 40 Ignition protection gap

[0081] 42 Ignition protection gap

[0082] 44 motor mounting and adjustment screws

[0083] 46 Filling opening

[0084] 48 Ignition protection gap

[0085] 50 screws

[0086] 52 mounting screws for 32

[0087] 53 assembly inserts

[0088] 54 Shaft coupling mounting screw

[0089] 56 Cable entry

[0090] 58 Ignition protection gap

[0091] 60 Pulley

[0092] 62 Housing end cap (optional)

[0093] 64 Motor mount

[0094] 66 Ignition protection gap

[0095] 68 lids

[0096] 70 Mounting screw for pulleys 60

[0097] 72 engine mounting screws

Claims

P2024,1077 WO N / P23-1594WO01 August 22, 2025 - 11 - Claims:

1. Encapsulated drive (10) with an electric motor (12) which has an output shaft (14), wherein the electric motor (12) is completely and the output shaft (14) is at least partially arranged in an encapsulated housing (16), the output shaft (14) is aligned axially with and connected to a shaft coupling (18) along its axis of rotation, at least one section of the shaft coupling (18) is led outwards through an opening (20) of the housing (16), and an ignition-proof ignition protection gap (22) is formed between the shaft coupling (18) and the housing (16).

2. Encapsulated drive (10) according to claim 1, wherein the shaft coupling (18) is rotatably mounted on the housing by means of at least one first (26), preferably with a first and a second bearing (26, 28) arranged offset from each other along the axis of rotation.

3. Encapsulated drive (10) according to claim 2, wherein the shaft coupling (18) is rotationally symmetrical and has a radially oriented flange (30), and optionally the two bearings (26, 28) are arranged on opposite sides of the flange (30).

4. Encapsulated drive (10) according to claim 3, wherein the first bearing (26) is arranged radially around the shaft coupling (18) between the side of the flange (30) facing away from the electric motor (12) and an end section (32) of the housing (16).

5. Encapsulated drive (10) according to claim 3 or 4, wherein the second bearing (28) is arranged radially around the shaft coupling between the side of the flange (30) facing the electric motor (12) and the electric motor (12). P2024,1077 WO N / P23-1594WO01 August 22, 2025 - 12 - 6. Encapsulated drive (10) according to one of claims 3 to 5, wherein the ignition protection gap (22) is formed between the housing (16) and an outwardly facing end surface (24) of the flange (30).

7. Encapsulated drive (10) according to one of claims 3 to 6, wherein the housing (16) has an end cover (32) which includes the opening (20) of the housing (16), and within which preferably a cup-shaped bearing sleeve (34) with a further opening (36) in a base of the bearing sleeve (34) is arranged, wherein the bearing sleeve (34) protrudes with its base from the opening (20) of the end cover (32) and the shaft coupling (18) protrudes from the further opening (36) of the bearing sleeve (34).

8. Encapsulated drive (10) according to claim 7, wherein the end surface (24) of the flange (30) forms the ignition protection gap (22) with an inner side of the bearing sleeve (34).

9. Encapsulated drive (10) according to claim 7 or 8, wherein the end cover (32) forms a second ignition protection gap (38) with the housing (16).

10. Encapsulated drive (10) according to one of claims 7 to 9, wherein an outer surface of the cup-shaped bearing sleeve (34) forms a third ignition protection gap (40) with the opening (20).

11. Encapsulated drive (10) according to one of claims 7 to 10, wherein the bearing (26) or bearings (26, 28) are arranged inside the bearing sleeve (34).

12. Encapsulated drive (10) according to one of claims 7 to 11, characterized in that the end cover (32) and the bearing sleeve (34) are formed in one piece.

13. Encapsulated drive (10) according to one of the preceding claims, wherein a fourth ignition protection gap (42) is provided between the shaft coupling (18) and the output shaft (14). P2024,1077 WO N / P23-1594WO01 August 22, 2025 - 13 - 14. Encapsulated drive (10) according to one of the claims relating to claim 2, wherein at least two, preferably three motor mounting and adjusting screws (44) are provided in the housing (16) to fix the electric motor (12) against the at least one bearing (26) and / or to adjust the ignition protection gap (22).

15. Encapsulated drive (10) according to one of the preceding claims, wherein a closable filling opening (46) on the housing (16) is provided for filling the housing (16) with an explosion suppression means, wherein the filling opening (46) can preferably be closed with a screw (50) which forms a fifth ignition protection gap (48) with the housing (16).

16. Encapsulated drive (10) according to one of the preceding claims, wherein the ignition protection gap (22) is formed between the opening (20) of the housing (18) or between a housing end (62) which forms the opening (20) of the housing (18) and a section of the shaft coupling which is arranged on a side of the first bearing (26) which is facing away from the electric motor (12).

17. Encapsulated drive (10) according to claim 16, wherein at least one bearing (26), preferably two bearings (26, 28) are provided, which are arranged within a bearing sleeve (34) which adjoins the housing end (62) in the direction of the electric motor (12).

18. Encapsulated drive (10) according to claim 17, wherein the housing (16) is made of a metal and the ignition protection gap (22) is formed between the opening (20) of the housing (16) and the shaft coupling (18), and preferably the bearing(s) (26, 28) are arranged directly between the housing (16) and a flange (30) of the shaft coupling (18).

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