Drive unit for electric outboard motor

Abstract

The invention relates to a drive unit (1) and a tailgate (30) for a drive unit (10) of an electric outboard motor (1), the tailgate (30) forming a part of a housing (20) of the drive unit (10), and having a cover section (32) which closes the housing (20) on the tail side and which has a propeller shaft opening (31), the propeller shaft opening defines an axial direction (A) and a propeller shaft (11) of the drive unit (10) can be guided outwards from the housing (20) through the propeller shaft opening; and a hollow cylindrical mounting section (35), which is arranged on the side facing away from the propeller shaft opening (31) when viewed in the axial direction (A); wherein the mounting section (35) has a cylindrical mounting surface (37) with a mounting thread (36) by means of which the tail cap (30) can be screwed as a whole onto a corresponding thread (22a) on the housing side of the housing (20).

Description

Technical Field

[0001] The invention relates to a drive unit for an electric boat drive, for example an outboard motor or a pod propeller, and in particular to a stern cover for such a drive unit. Background Art

[0002] Outboard motors or pod propellers with an electric drive are known in the field of boat drives. Electric drives have several advantages over internal combustion engines. Thus, electric outboard motors are very quiet in operation and do not emit exhaust gases into the environment. Water contamination or accidental oil spills during refueling can be excluded.

[0003] The drive unit of such an outboard motor can have a multi-part housing, for example, in order to be able to open and maintain the drive unit. In this case, the drive unit usually has a tail cover made of metal arranged on the side of the propeller, which is machined, coated and fastened to the housing of the drive unit with screws.

[0004] If different metal materials are used, the multi-piece form of the housing of the drive unit may cause galvanic corrosion when in contact with water, especially seawater. In addition, the assembly process of the tail cover is consuming, because not only a certain number of bolts must be tightened, but also the axial degree of the tail cover relative to the housing must be ensured. Summary of the invention

[0005] The object of the present invention is to provide an improved drive unit for an electric outboard motor or a podded propeller, in particular to provide an improved transom for such a drive unit.

[0006] This object is achieved by a tailgate having the features of the invention and a drive unit having the features of the invention. Advantageous developments emerge from the following figures and the description of preferred exemplary embodiments of the invention.

[0007] The stern cover according to the invention is designed for a drive unit of an electric outboard motor or a pod propeller. Here, the stern cover forms part of the housing of the drive unit, in particular on the propeller side of the drive unit. The propeller side of the drive unit is also referred to as the "stern side" here.

[0008] The tail cover has a covering section that closes the housing on the tail side. The covering section has a propeller shaft opening, which defines an axial direction and through which the propeller shaft of the drive unit extending in the axial direction can be guided outward from the housing. In addition, the drive unit has a hollow cylindrical assembly section, which is arranged on the side facing away from the propeller shaft opening when viewed in the axial direction. The assembly section extends as a cylindrical wall at the outer circumference of the covering section. Therefore, the tail cover has a bowl shape, the bottom of which is formed by the covering section and surrounded by the assembly section at the outer circumference.

[0009] The mounting section has a cylindrical mounting surface with a mounting thread, through which the tail cap can be screwed as a whole onto the corresponding housing-side thread of the housing. The position of the mounting surface preferably corresponds to the nominal diameter of the mounting thread, ie the maximum diameter of the mounting thread.

[0010] The assembly of the tail cap is realized by an integrated assembly thread without the need for additional fastening mechanisms, such as bolts, etc. The assembly process is thus accelerated and can be reliably performed. The assembly thread also provides sealing as a synergistic effect to prevent water or other external media from entering the drive unit.

[0011] Preferably, the mounting thread is implemented as an internal thread and is arranged on the mounting surface of the mounting section in such a way that the flank of the mounting thread extends as a projection from the mounting surface into the interior of the hollow cylindrical mounting section. In this way, the handling and assembly capability of the tail cap is further improved.

[0012] Preferably, viewed in the axial direction toward the cover section (that is to say on the rear side), the mounting section has, in addition to the mounting surface, a cylindrical centering surface, which is configured to ensure centering relative to the housing during the mounting of the tail cap, in that it forms a positive fit with a corresponding housing-side centering surface of the housing. The integration of the centering surface into the mounting section increases the reliability of the mounting process, in particular with regard to the axial alignment of the tail cap relative to the rest of the housing.

[0013] Preferably, the diameter of the centering surface, viewed in a cross section perpendicular to the axial direction, is smaller than the corresponding diameter of the mounting surface, thereby optimizing the centering function. Particularly preferably, the diameter of the centering surface, viewed in a cross section perpendicular to the axial direction, corresponds to the thread pitch of the mounting thread, that is to say, in this case, the two diameters are substantially identical. The centering function is maximized by the centering surface being approximately at the level of the thread pitch of the mounting thread.

[0014] Preferably, the mounting section has, in addition to the mounting surface, a cylindrical sealing surface, viewed in the axial direction relative to the cover section (i.e. on the housing side), which is provided and configured for sealing the housing in such a way that a housing seal can be mounted between the sealing surface and a corresponding sealing seat of the housing. The housing seal is preferably designed as an O-ring. In this way, the tail cap and the rest of the housing are reliably sealed in order to prevent water or other external media from entering the interior of the drive unit.

[0015] Preferably, the diameter of the sealing surface, viewed in a cross section perpendicular to the axial direction, is greater than a corresponding diameter of the mounting surface, whereby the housing seal and the mounting thread jointly ensure the seal.

[0016] Preferably, the propeller shaft opening has a sealing seat for accommodating a shaft seal for sealing relative to the propeller shaft and / or a bearing seat for accommodating a bearing, preferably a rolling bearing, for rotatably supporting the propeller shaft, wherein the sealing seat preferably has a smaller diameter than the bearing seat when viewed in a cross section perpendicular to the axial direction. By integrating the bearing seat and / or the sealing seat into the tail cover, the drive unit can be designed particularly compactly.

[0017] The tailgate is preferably designed to be rotationally symmetrical, thereby further improving the assembly capability and production of the tailgate.

[0018] Preferably, the tail cap is made of plastic, thereby eliminating the risk of corrosion, especially the risk of galvanic corrosion caused by metal pairing. In addition, the use of plastic, which is lighter than, for example, metal die castings, leads to cost reduction and weight reduction. For example, coating of the tail cap to avoid corrosion can be omitted.

[0019] In order to further reduce the assembly effort, weight and costs, the tailgate is preferably manufactured in one piece or in one piece.

[0020] In addition, the above-mentioned purpose is achieved by a drive unit for an electric outboard motor, wherein the drive unit has: a housing having a tail cover according to any of the above-mentioned embodiments; an electric motor arranged in the housing; and a propeller shaft to be rotationally driven by the electric motor, wherein the propeller shaft extends in an axial direction in the housing and extends outward through a propeller shaft opening section.

[0021] The features, technical effects, advantages and embodiments described with respect to the tail cover are similarly applicable to the drive unit.

[0022] Other advantages and features of the present invention are apparent from the following description of preferred embodiments. The features described therein can be implemented individually or in combination with one or more of the above features, as long as these features are not contradictory. The following description of preferred embodiments is hereby carried out with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Preferred further embodiments of the present invention are explained in detail by the following description of the accompanying drawings. Here, it is shown:

[0024] Figure 1 shows a perspective exterior view of a drive unit for an outboard motor according to one embodiment;

[0025] Figure 2 A cross-sectional view showing a rear section of a drive unit with a screwed-on tail cap;

[0026] Figure 3 A perspective view showing a tail cap; and

[0027] Figure 4 Show Figure 2 An enlarged detail of the sectional view of is used to illustrate the centering of the tail cover. DETAILED DESCRIPTION

[0028] In the following, preferred embodiments are described with reference to the drawings. Identical, similar or identically acting elements are provided with the same reference numerals in the drawings, and a repeated description of these elements is partially omitted in order to avoid redundancy.

[0029] Figure 1 FIG. 1 shows a perspective exterior view of an electric drive unit 10 for an outboard motor 1 according to one embodiment. Figure 1 An outboard motor 1 is partially shown in FIG, wherein the shaft 2 can be seen, to which the drive unit 10 is fastened. Figure 1 The components on the ship's side, including for example the batteries, are not shown. The drive unit 10 is located below the water surface in normal operation.

[0030] The drive unit 10 can also be part of a pod-type propeller and then also be arranged below the water surface in normal operation.

[0031] The drive unit 10 has a housing 20, which in the present embodiment is constructed in three parts, including a dome-shaped front housing section 21, a cylindrical middle housing section 22 and a tail cover 30. The overall shape of the housing 20 is preferably optimized in terms of flow dynamics, whereby the housing can have an elongated, rounded, slightly drop-shaped or tower-shaped geometry. In the present embodiment, the housing 20 as a whole and the housing sections 21, 22, 30 are constructed in a substantially rotationally symmetrical manner.

[0032] The front housing section 21 is preferably made of plastic as a front cover and is preferably provided with an internal thread so that it can be screwed directly into the middle housing section 22. For this purpose, the front housing section 21 can have a recess 21a, which serves as an engagement point for a tool in order to screw the front housing section 21. Alternatively, the front housing section 21 and / or the middle housing section 22 can be made of a metal material, for example in the form of a metal die-casting.

[0033] The tail cover 30 which closes the housing 20 on the tail side, ie on the propeller side, is preferably made of plastic.

[0034] The propeller shaft 11 extends in the housing 20 in the axial direction, is supported in the tail cover 30 and emerges in sections from the housing 20. In normal operation, a propeller (not shown in the figure) is fastened to the tail end section of the propeller shaft 11.

[0035] In order to drive the propeller shaft 11, the drive unit 10 has an electric motor 12, see Figure 2 The electric motor 12 is preferably a synchronous motor. In the present embodiment, the electric motor 12 is used as a direct drive, that is, the electric motor 12 transmits the generated torque directly to the propeller shaft 11 without a transmission. However, the use of a transmission, a clutch, etc. is not excluded.

[0036] Figure 3 The tail cover 30 is a rotationally symmetrical, truncated cone-shaped or cylindrical object which is provided on the tail side, that is to say on the propeller side, with the exception of the central propeller shaft opening 31 by a covering section 32 (see Figure 2 ) is closed, and the propeller shaft 11 extends outward from the housing 20 of the drive unit 10 through the propeller shaft opening. The axial direction A is defined by the rotationally symmetrical shape of the tail cover 30, which coincides with the axial extension of the propeller shaft 11. The tail cover 30 has a covering section 32 on the tail side, which closes the housing 20 on the propeller side. The covering section 32 forms or includes a covering surface of a "truncated cone" and is closed except for the propeller shaft opening 31, while the tail cover 30 is more precisely hollow cylindrical on the side facing away from the propeller shaft opening 31 and is open for assembly with the middle housing section 22.

[0037] The propeller shaft opening 31 comprises a sealing seat 31a. In the assembled state of the drive unit 10, the shaft seal 13 is arranged between the sealing seat 31a and the propeller shaft 11, see also Figure 2The shaft seal 13 prevents water or other external media from entering the drive unit 10. Furthermore, the propeller shaft opening 31 comprises a bearing seat 31 b in which a bearing 14, in particular a rolling bearing, is arranged for rotatably supporting the propeller shaft 11 in the assembled state of the drive unit, see also Figure 2 Therefore, the bearing seat 31b of the propeller shaft 11 is placed in the tail cover 30. Preferably, the sealing seat 31a has a smaller diameter than the bearing seat 31b.

[0038] On the side facing away from the propeller shaft opening 31 , the tail cover 30 has a hollow cylindrical mounting section 35 for connection to the central housing section 22 .

[0039] The mounting section 35 has a mounting thread 36 which interacts with a corresponding housing-side thread 22 a of the central housing section 22 , see Figure 4 The tail cap 30 can thus be screwed as a whole onto the tail-side end section of the central housing section 22 .

[0040] The mounting thread 36 is preferably implemented as an internal thread and is arranged on the cylindrical mounting surface 37 of the mounting section 35, so that its flanks or teeth extend as projections from the mounting surface 37 inwardly, that is, toward the propeller shaft 11. In addition, the mounting thread 36 does not have to extend completely around the mounting surface 37, but the mounting thread 36 can be as in Figure 3 As shown in the present embodiment, the plurality of ferrules are arranged in sections in the form of groups along the circumference.

[0041] Viewed in the axial direction A, a likewise cylindrical centering surface 38 adjoins the cylindrical mounting surface 37 on the rear side, said centering surface being configured to ensure centering of the tail cover 30 relative to the middle housing section 22 during assembly. The mounting surface 37 and the centering surface 38 are inner surfaces of the hollow cylindrical mounting section 35. Preferably, the centering surface 38 has a smaller radial spacing from the propeller shaft 11 than the mounting surface 37. In other words, viewed in a cross section perpendicular to the axial direction A, the diameter 37 of the centering surface 38 is preferably smaller than the diameter of the mounting surface 37, also viewed in a cross section perpendicular to the axial direction A. Viewed in a cross section perpendicular to the axial direction A, the diameter of the centering surface 38 preferably corresponds to the thread pitch of the mounting thread 36, that is to say to the smallest diameter of the internal thread geometry.

[0042] During the assembly of the tail cap 30 , the centering surface 38 forms a positive fit with the corresponding centering surface 22 b of the middle housing section 22 on the housing side, as shown in FIG. Figure 4 As shown in , the axial alignment of the tail cover 30 relative to the middle housing section 22 is thereby ensured.

[0043] Viewed in the axial direction A, a sealing surface 39 is connected to the side of the mounting section 35 facing the middle housing section 22, and the diameter of the sealing surface is preferably larger than the corresponding diameter of the mounting surface 37 when viewed in a cross section perpendicular to the axial direction A. A housing seal 15, preferably in the form of an O-ring, is installed between the sealing surface 39 and the corresponding sealing seat 22c of the middle housing section 22 to seal the tail cover 30 and the middle housing section 22 relative to each other.

[0044] The tail cap 30 , which includes the cover section 32 , the mounting section 35 , the mounting thread 36 , the mounting surface 37 , the centering surface 38 and the sealing surface 39 , is made of plastic and is preferably formed integrally or in one piece.

[0045] The assembly of the tail cover 30 described above is achieved by the integrated assembly thread without the need for additional fastening mechanisms, such as bolts, etc. The assembly process is accelerated. In addition, the integration of the centering surface 38 improves the reliability of the assembly process, especially with respect to the axial degree of the tail cover 30 relative to the rest of the housing 20.

[0046] By making the tail cap 30 from plastic, the risk of corrosion, in particular the risk of galvanic corrosion caused by metal pairing, is eliminated. In addition, cost reduction and weight reduction are caused by using lighter plastics than, for example, metal die castings. Coating of the tail cap, for example, to avoid corrosion, can be omitted.

[0047] As far as applicable, all individual features shown in the exemplary embodiments may be combined with one another and / or replaced with one another, without departing from the scope of the present invention.

[0048] Reference numerals list

[0049] 1 Outboard Motor

[0050] 2 Axis

[0051] 10Electric drive unit

[0052] 11 Propeller shaft

[0053] 12 Electric motor

[0054] 13 Shaft seals

[0055] 14 Bearings

[0056] 15 Housing seal

[0057] 20 Shell

[0058] 21 Front housing section

[0059] 21a Depression

[0060] 22 Middle housing section

[0061] 22a Thread on housing side

[0062] 22b Centering surface on housing side

[0063] 22c Seal seat

[0064] 30 tail cover

[0065] 31 Propeller shaft opening

[0066] 31a Seal seat

[0067] 31b Bearing seat

[0068] 32 Covering Sections

[0069] 35 Assembly Section

[0070] 36 Assembly thread

[0071] 37 Assembly surface

[0072] 38 Centering surface

[0073] 39 Sealing surface

[0074] A Axial direction

Claims

1. A transom (30) for a drive unit (10) of an electric outboard motor (1) or a podded propulsion system, wherein the transom (30) forms part of a housing (20) of the drive unit (10) and comprises: a cover section (32) which closes the housing (20) at the rear end and has a propeller shaft opening (31) which defines an axial direction (A) and through which a propeller shaft (11) of the drive unit (10) can be guided outward from the housing (20); and A hollow cylindrical mounting section (35) which, when viewed in the axial direction (A), is arranged on a side facing away from the propeller shaft opening (31); in The mounting section (35) has a cylindrical mounting surface (37) with a mounting thread (36), by means of which the tail cap (30) as a whole can be screwed onto a corresponding housing-side thread (22a) of the housing (20).

2. The tail cover (30) according to claim 1, It is characterized in that The mounting thread (36) is designed as an internal thread and is arranged on the mounting surface (37) of the mounting section (35) such that side surfaces of the mounting thread (36) extend as projections from the mounting surface (37) into the interior of the hollow-cylindrical mounting section (35).

3. The tail cover (30) according to claim 1 or 2, It is characterized in that When viewed in the axial direction (A) toward the cover section (32), the mounting section (35) has, in addition to the mounting surface (37), a cylindrical centering surface (38), which is configured to ensure centering relative to the housing (20) during assembly of the tail cover (30) in such a way that the centering surface (38) forms a positive fit with a corresponding housing-side centering surface (22b) of the housing (20).

4. The tail cover (30) according to claim 3, It is characterized in that When viewed in a cross section perpendicular to the axial direction (A), the diameter of the centering surface (38) is smaller than the corresponding diameter of the assembly surface (37), wherein when viewed in a cross section perpendicular to the axial direction (A), the diameter of the centering surface (38) preferably corresponds to the thread pitch of the assembly thread (36).

5. A tail cap (30) according to any one of the preceding claims, It is characterized in that When viewed in the axial direction (A) relative to the covering section (32), the mounting section (35) has, in addition to the mounting surface (37), a cylindrical sealing surface (39), which is provided for sealing the housing (20) in such a way that a housing seal (15) can be mounted between the sealing surface (39) and a corresponding sealing seat (22c) of the housing (20).

6. The tail cover (30) according to claim 5, It is characterized in that When viewed in a cross section perpendicular to the axial direction (A), the diameter of the sealing surface (39) is greater than a corresponding diameter of the mounting surface (37).

7. A tail cap (30) according to any one of the preceding claims, It is characterized in that The propeller shaft opening (31) has a sealing seat (31a) for accommodating a shaft seal (13) for sealing relative to the propeller shaft (11) and / or a bearing seat (31b) for accommodating a bearing (14) for rotatably supporting the propeller shaft (11), wherein the sealing seat (31a) preferably has a smaller diameter than the bearing seat (31b) when viewed in a cross section perpendicular to the axial direction (A).

8. A tail cap (30) according to any one of the preceding claims, It is characterized in that The tail cover (30) is designed to be rotationally symmetrical.

9. A tail cap (30) according to any one of the preceding claims, It is characterized in that The tail cover (30) is made of plastic.

10. The tail cap (30) according to any one of the preceding claims, It is characterized in that The tail cover (30) is manufactured in one piece.

11. A drive unit (10) for an electric outboard motor (1), wherein the drive unit (10) comprises: A housing (10) having a tail cap (30) according to any one of the preceding claims; An electric motor (12) is arranged in the housing (10) and a propeller shaft (11) to be rotationally driven by the electric motor (12), the propeller shaft extending in the housing (10) in the axial direction (A) and extending outward in sections through the propeller shaft opening (31).

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