DE102021107317A1 - Motor assembly with sealed housing cover - Google Patents

Abstract

A motor arrangement (2) with an electric motor (4) and an electric control unit (6) for the motor (4) contains a housing (8) with a motor section (10) for the motor (4) and with a receiving section (12) with a sealed accommodation space (14) for the control unit (6), the accommodation section (12) comprising a lower part (18) with an opening (20) and a removable cover (22) with at least one hold-down device (26), the accommodation section (14 ) comprises a sealing arrangement (34) with a groove (36), an inlaid tongue (38) and sealing means (40) which run along an edge line (24), the edge line (24) having a radius of curvature (R) at every point which is greater than 5% of the maximum transverse extent (Q) of a sealing surface (46) delimited by the edge line (24). In a method for assembling the engine assembly (2), the cover (22) and lower part (18) are assembled in an assembly device (62) fixed, the sealant (40) filled into the groove (36), the cover (22) placed on the lower part (18) in a desired relative position with the aid of the assembly device (50) and the cover (22) is fixed to the lower part (18).

Description

The invention relates to a motor arrangement with an electric motor, an electric control unit for controlling the motor and a housing which is fastened to the motor and has a receiving space in which the control unit is protected from environmental influences.

Such a motor arrangement is, for example, from US 9,997,980 B2 known. The receiving space is formed here from a lower part in the form of a connector housing and a cover part. A sealing arrangement, comprising a sealing groove and an insert section lying in this groove, seals the cover part and connector housing from one another. For this purpose, a gap between the sealing groove and the insert section is filled with a sealing material.

Such motors are also used in adverse environments. The materials protecting the receiving space, e.g. a housing with a cover, can come into contact with aggressive oils. For example, such a motor is used to operate in an automatic transmission of a vehicle. The engine is connected to transmission oil, which can also reach the materials protecting the receiving space.

The object of the present invention is to propose improvements with regard to a motor arrangement.

The object is achieved by a motor arrangement according to claim 1. Preferred or advantageous embodiments of the invention and other categories of the invention result from the further claims, the following description and the attached figures.

The motor assembly includes an electric motor and an electric motor control unit electrically connected thereto. The term "control unit" means any electrical / electronic circuit or wiring that is used to connect the motor. In the simplest case, this can also be, for example, two simple electrical conductors to which an interference suppression capacitor, a reverse polarity protection diode or the like is connected. As a rule, however, this will involve at least one control board for the motor, e.g. for its speed control / regulation or the like.

The motor assembly includes a housing that includes a motor portion in or on which the motor is mounted. The housing also has a receiving portion. This is used to hold the control unit. The accommodating section includes an accommodating space for the control unit. The control unit is protectively enclosed in the receiving space. The accommodation space is therefore sealed off from the engine section and the environment or an exterior space surrounding the engine arrangement.

The receiving portion includes a base. This delimits the recording space. The lower part has an opening for or as access to the accommodation space, in particular for inserting or removing the control unit into or out of the accommodation space. "Delimiting" is to be understood in such a way that the lower part does not completely enclose the receiving space, but the receiving space is still open only at the opening. The receiving space is then completely and tightly encompassed or enclosed by the lower part and the cover only by a cover closing the opening. With regard to "openings", e.g. bushings for cables / conductors / other lines etc. through the cover and/or the lower part or the corresponding walls of the housing are not taken into account, which are then sealed in such a way that the receiving space is tightly enclosed is. These serve in particular to connect the motor and control unit and to connect the control unit to an external power supply. Several openings (with covers) can also be provided on the receiving space. In particular, there are only passages for electrical contacts through the lower part and in particular no passages through the cover and in particular no passages for the exchange of air/gas (e.g. pressure equalization) between the receiving space and the outside space.

The receiving section also contains the removable cover sealing the opening along a peripheral edge line. The edge line specifies that (imaginary) line or that area or course which surrounds the opening and on which the sealing between the cover and the lower part takes place.

The motor assembly includes at least one hold-down. By this is - in an assembled state - the cover - pressed against the lower part - with the interposition of a sealing arrangement. In this case, the cover and the lower part bear against one another in particular on at least one contact surface in the assembled state or are pressed against one another there. There are mutual contact elements on the cover and base, which touch each other on the contact surfaces in the assembled state or are pressed against one another there. The hold-down devices contain clamp or screw connections or the like, for example, in order to generate the required hold-down pressure. In the assembled state, for example, one or more screws of this hold-down device are then determined properly tightened to create or maintain hold down pressure. The individual hold-down device acts in particular at the appropriate point in relation to its exertion of force, for example by means of a screw which generates the hold-down force at specific points.

The receiving section contains the sealing arrangement. This runs along the edge line, encircling the opening and sealing the lid and base from each other. The sealing arrangement contains a groove also running along the edge line and a tongue lying in the groove (when the cover is in place, see below), also running along the edge line, and a sealant also running along the edge line, which is located in a gap between tongue and groove . These three components therefore run around the opening in a ring without gaps and seal the lower part against the cover.

“Along the edge line” means that the corresponding course of the finitely extended sealing arrangement takes place parallel to the ideally linear edge line, in particular also at a distance from it, or follows the course true to form. In particular, however, the edge line runs in, in particular in the center of the groove.

Either the groove is an element of the base and the tongue is an element of the cover; or the groove is an element of the cover and the tongue is an element of the base.

The groove and tongue are designed to be non-contact with one another and separated or spaced apart from one another by a gap, particularly in the assembled state—that is, when the cover and base are in contact at the contact surfaces. At least one area of the gap is filled with sealant

The sealant lies in the gap between the groove and tongue, so a liquid seal can be used in particular, which can be displaced practically without force in the liquid state during assembly of the cover and is then distributed in the gap. The sealant is therefore in particular a hardened liquid seal. In particular, the sealing agent (when introduced into the groove) has a viscosity in the range between 350 Pas and 550 Pas, in particular between 400 Pas and 500 Pas, in particular 440 Pas.

Unless otherwise stated, all dimensions, quantities, measurements, etc. are given with a certain customary tolerance, which the specialist chooses according to the situation according to his liquid expertise, e.g. 0.5mm +/- 10% for manufacturing tolerances . Permitted tolerances here are in particular a maximum of 20%, a maximum of 15%, a maximum of 10%, a maximum of 5%, a maximum of 3%, a maximum of 2%, a maximum of 1%, a maximum of 0.1%.

The gap is completely and continuously filled with the sealant along the edge line. Thus, no gap is left in the sealing arrangement in the circumferential direction of the opening and the latter is completely sealed in connection with the base and the cover.

The edge line and thus the course of the groove delimits a sealing surface. In particular, the sealing surface corresponds to the opening. This sealing surface has a maximum transverse extent. The maximum transverse extent is the longest straight line that can be drawn between two points on the edge line. With an ellipse as the edge line, the transverse extent would correspond to the main axis.

The edge line has a radius of curvature at every point that is greater than 5%, in particular greater than 10%, in particular greater than 12.5%, in particular greater than 15% of the value of the maximum transverse extent of the sealing surface delimited by the edge line is.

According to these features, in particular the relationship between the transverse extent and thus the size of the sealing surface and the smallest radius of curvature of the edge line or groove-tongue seal profile, the result is a rounded or comparatively (i.e. in relation to the size and thus transverse extent of the sealing surface) “soft” shape or course of the sealing line and thus the groove. The shape avoids corners or comparatively small and therefore "aggressive" radii or comparatively "strong" curvatures of the groove.

The invention is based on the finding that such comparatively small radii or corners can result in the necessary thickness of the sealant in the gap between tongue and groove not always being able to be ensured. A uniform sealant thickness in the gap can thus be ensured by the correspondingly soft or round groove profile with the given minimum radii. It is also possible in this way to avoid the otherwise possibly occurring high mechanical stress loads on the sealant at corners or small radii of the groove, which are caused by thermal expansion and the movement between groove and tongue caused by this. In addition, with a correspondingly soft groove profile, the dosing of the liquid sealant into the groove is improved with regard to the reduced risk of bubble formation, which can also occur more easily in tight radii / corners. Such bubbles can cause leaks in the sealing arrangement to lead. According to the invention, the result is in particular an improved, smoothed course of the groove while avoiding radii of the course of the groove that are disproportionately small in relation to the transverse extent.

In a preferred embodiment, the motor assembly has at least four hold-down devices. The hold-down devices are arranged along the edge line and are spaced apart from one another along the edge line. Based on an average of all distances, the hold-down devices are evenly distributed with regard to their distances along the edge line with a deviation of at most 30%, in particular at most 20%, in particular at most 18%, in particular at most 15%, in particular at most 10%, in particular at most 5%. The distances therefore all show at most the specified percentage deviation from the mean. The respective "distance" is measured along the edge line, in particular the center of the course of the groove, and can therefore have a curved shape. The distance is then the length of the corresponding section of the border line. For hold-down devices that do not lie on the edge line, the distance reference point on the edge line counts as the or a perpendicular projection of the position of the hold-down device onto the nearest section of the edge line. In terms of the deviations mentioned, the hold-down devices are distributed "evenly" over the circumference of the edge line, in particular with regard to the circumference of the groove. The "position of a hold-down device" is also related to its center, in particular a central axis of a screw connection of the hold-down device.

The "equal distribution" of hold-down devices, especially screws that fix them at certain points, over the circumference of the groove ensures a constant surface pressure between the cover and the lower part, which further increases the quality / tightness of the sealing arrangement. The advantage arises in particular in combination with the “soft” progression of the sealing arrangement according to the invention and also in particular with the particularly simple progression shapes (not concave, rectangular, etc.) presented further below. In particular, this avoids uneven loading of the sealant between the groove and tongue due to fluctuating contact pressure along the course of the groove, with this fluctuation also being able to arise, among other things, from a pressure difference between the hermetically sealed receiving space and the environment.

In a preferred embodiment, the opening is the only opening in the receiving space with a single—particularly removable—cover. Otherwise, only permanently cast and/or sealed leadthroughs through the walls of the receiving space are present in the receiving space. For these bushings, it is assumed or are designed in such a way that they meet the desired tightness requirements of the receiving space. The sealing of the cover according to the invention, which then also meets these tightness requirements, thus leads to an overall optimally sealed receiving space.

In a preferred embodiment, the edge line, and thus the course of the groove, has exclusively non-concave sections with respect to the sealing surface. The sealing surface or the surface delimited by the groove thus has an exclusively non-concave edge, that is to say with sections that are convex throughout and at most with straight sections. This results in a completely round and particularly simple shape of the groove profile, which ensures even better sealing properties of the groove.

In a preferred variant of this embodiment, the edge line—and thus again the course of the groove—is designed in the manner of a square with rounded corners. The edge line is therefore composed of four straight sections, and between each two of the straight sections lies one of four purely convex sections, in particular curves running in the shape of segments of a circle, as the four “rounded corners” of the quadrilateral. Such a shape is particularly easy to design.

In a preferred variant of this embodiment, the edge line (and thus again the course of the groove) runs or is designed in the manner of a non-square rectangle. "By type" is to be understood in such a way that the square shape (with rounded corners) is in particular at least approximately a rectangular shape in terms of its basic shape, i.e. that its opposing straight sections are actually or at least almost parallel, for example with a maximum angle of 5°, 10 ° or 15° to each other. Since the corresponding shape of the groove usually also determines the shape of the opening, quadrangular circuit boards in the form of control units/components designed in a simple form can be inserted through the opening into the receiving space.

In a preferred embodiment, at least six hold-down devices are provided, in particular exactly six, which are distributed around the opening in the circumferential direction of the latter. In particular, at least one, in particular all, of the hold-down device contains at least, in particular precisely, a locally concentrated holding means such as a screw, a pin, a clip or the like, which brings about the hold-down. In particular, the hold-down devices are completely radially outside of the sealing surface and thus outside of the opening and sealing arrangement. As a result, the hold-down devices do not have any negative effects on the sealing arrangement. A total of six screws prevent local overloading of the cover or base and exert particularly even pressure on the entire sealing arrangement.

In a preferred variant of this embodiment in combination with the design in the manner of a square, two hold-down devices are arranged in the area of each longitudinal side of the square shape or of the square, and one hold-down device is arranged in the area of each narrow side of the quadrilateral shape. "In the area" is to be understood in such a way that this refers to the ideally quadrangular basic shape without rounded corners. The hold-down devices therefore do not necessarily have to be arranged on a straight section of the edge line pointing to the respective side of the square, but can also be placed in the first half of a curve adjoining this straight section, which is therefore still on the same side of the ideal square as the straight section is assigned.

In a preferred embodiment, the hold-down device is set up exclusively for mutually holding the cover and base, not for achieving any other fixing function of the motor assembly. The hold-down device is not used, for example, to attach the housing, the motor, etc. to a counterpart. Also not to e.g. attach the cover or the base alone or together to a different component. The hold-down device is therefore used solely to fix the cover and base relative to one another and to hold them in position, and is separate from any other fixing function in the motor arrangement. In this way, particularly with regard to the hold-down force, the cover can be held down on the lower part in a particularly precisely dimensioned manner. The hold-down devices therefore have the sole task of pressing the cover evenly against the lower part with a predetermined or dimensioned force with regard to the sealing arrangement.

In a preferred embodiment, at least the base is made of a polyphthalamide material. In particular, the entire housing is made of this material except for the cover. The material is in particular glass fiber reinforced, in particular with a weight proportion of 20% to 40%, in particular 30% to 33% glass fibers. The material in question is particularly resistant to the aggressive oils mentioned above and also has a coefficient of thermal expansion that corresponds (with sufficient tolerance) to that of aluminum (particularly the manufacturing material for the cover).

Alternatively or additionally, the cover is made from an aluminum material. This results in a particularly advantageous combination with the polyphthalamide mentioned above with regard to the same coefficients of thermal expansion. Dimensional changes in the sealing arrangement and the groove caused by different thermal expansion and thus stresses in the sealant are thus largely avoided.

In a preferred embodiment, the lower part and the cover have the same coefficient of thermal expansion in terms of their materials, with deviations in the values of up to 10% preferably still being referred to as “same” coefficients. This leads to the advantages mentioned above and applies in particular to the choice of material aluminum / polyphthalamide mentioned above.

In a preferred embodiment, the sealant consists of a polyacrylate material. "Exists" is to be understood in such a way that the material may contain specialist or commercial additives to polyacrylate for sealants. The corresponding material is offered in particular under the trade name "Loctite". In the present case, such seals are cured in particular in an atmosphere with a maximum humidity of 70% and/or at a temperature of 40°C and/or at a temperature below 65°C. This prevents the methanol contained in the material from starting to boil, which could lead to the disadvantageous formation of bubbles in the sealant. This results in particularly high-quality seals from the sealant in question.

In a preferred embodiment, the motor arrangement has no positioning aid for positioning the cover relative to the base in a desired position. The target position is that assembly position in which the intended or desired or predetermined or specifiable gap geometry is achieved by the intended relative position of the cover and base and thus of the groove and tongue. Instead, an external assembly device is used here in particular. This results in the advantage that a readjustment for the exact intended placement of the cover on the lower part in order to achieve the intended gap geometry is possible at any time by adjusting or changing the assembly device. Manufacturing tolerances with regard to the cover or base or the groove or the tongue can also be corrected during the assembly of the motor arrangement, specifically the cover on the base. The fixation of the lid relative to the base in the selected position then results, as described above, by the fixing effect of the hold-down devices.

The object of the invention is also achieved by a method for assembling a motor assembly according to claim 14. In the method, the cover and at least the lower part of the remaining motor assembly, in particular the entire remaining motor assembly, are fixed in an assembly device. Before or in particular after this step, the sealant is introduced into the groove, in particular poured into the groove in a free-flowing or liquid form. The cover is then placed on the lower part in a desired relative position with the aid of the assembly device. This is brought about in particular by a linear movement, the movement taking place in an assembly direction, in particular along an axis of symmetry of the groove--related to its cross section. Finally, the cover is fixed to the lower part with the help of the hold-down device.

In particular, there is no positioning aid (cover relative to the lower part) on the motor arrangement, but purely external positioning by the assembly device. As explained above, it is possible to adjust the tongue in the groove at the time of assembly, independently of the manufacture of the components of the motor arrangement.

In particular, the cover is pressed onto the lower part using the assembly device with a force of 1500 to 2500 N, in particular 2000 N, in particular 2000 N +/- 10%. The cover is fixed to the lower part with the aid of the hold-down device, in particular by tightening its screws, preferably with a tightening force of between 1 Nm and 3 Nm, in particular with 1.2 Nm, in particular with a tolerance of +/-10%. In particular, when using a sealant that is free-flowing or liquid in the installed state, its presence has no effect on the pressing force, since this gives way in the groove with virtually no force when the cover is applied to the lower part and is distributed in the gap. In particular, the depth of penetration of the tongue into the groove is set exactly as intended via the pressing force of the assembly device.

The method and at least some of its possible embodiments and the respective advantages have already been explained in connection with the engine arrangement according to the invention.

It is optionally possible that, for better distribution of the sealing compound, the cover is made to oscillate during or after it is fed in, as a result of which the sealant is distributed more evenly on the gap contour. The amplitude of the vibration is significantly smaller than the gap width, in particular less than 20% of the gap width.

In a preferred embodiment, before the sealant is introduced into the groove, the latter is cleaned with the aid of a plasma and/or activated for the sealant, at least in the area that comes into contact with the sealant. In this case, plasma with a surface energy of at least 30 mN/m, in particular at least 36 mN/m, in particular at least 40 mN/m, in particular at least 58 mN/m, is used. Especially in connection with the above-mentioned materials, the plasma treatment leads to a particularly high-quality sealing effect. Optionally, a laser cleaning of the lid (particularly aluminium) is also carried out. This improves the adhesion of the sealant to the base and the cover. The plasma treatment prevents gaps between the material (base/cover) and the sealant.

In particular, the invention is based on an application of the motor arrangement in which it is located within a transmission housing. In doing so, it comes into contact with automatic transmission oil, e.g. the product "Shell ATF 818". The engine arrangement can be exposed to ambient temperatures of -40°C to 150°C, e.g. in the form of the oil sump temperature.

The invention is based in particular on the following engine arrangement (in particular the overall combination, but sub-combinations of the individual aspects are possible): the receiving space has a volume of 25 cubic centimeters, the housing material (lower part, receiving section or entire housing) is PPA GF 33, the cover material is aluminum and the material of the sealant is polyacrylate. The accommodating space or its wall may have leadthroughs for electrical connection terminals, which are cast into the housing. These are used, for example, for the power supply and/or communication (electrical signals) of the receiving space as a "dry space" with a "wet space", i.e. the engine section or the environment.

The motor arrangement is to be tested using the test methods customary in the automotive sector. The goal is a sufficient seal between the base and the cover.

The invention is based on the finding that the main cause of bubbles in the sealant in the gap is methanol, which is produced when the sealant hardens. The methanol bubbles should be prevented, the methanol should be able to escape during hardening. The curing should take place from the outside to the inside (i.e. towards the receiving space). because inside, ie in the receiving space, there is not enough moisture available to react with the sealant. Due to the invention, due to the only comparatively slightly curved groove, a particularly uniform dosing of sealant can take place and the formation of methanol bubbles can be prevented. The sealant is preferably cured at approx. 40° C./70% relative humidity in order to improve curing. The drying of the methanol is then improved at elevated temperature (eg 60° C. in dry air).

The invention is based on the consideration of using a sealant with a comparatively sufficiently high viscosity in order to avoid its removal by pressure (washing out) during assembly; at the same time, the sealant is flexible enough in connection with the selected groove contour, which is slightly curved in relation to the size of the sealing surface, to absorb material stress due to thermal shocks. The cleaning / plasma process removes residues from the previous manufacturing processes and activates the surface of the materials (lower part and lid).

• 1 eine stark stilisierte Motoranordnung im Seitenschnitt mit Dichtanordnung,
• 2 eine konkrete Motoranordnung in einer perspektivischen Schrägansicht mit abgenommenem Deckel und ohne Steuereinheit,
• 3 die weiter stilisierte Motoranordnung aus 1 beim Aufsetzen des Deckels in Schrägansicht.

Further features, effects and advantages of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. Show, each in a schematic principle sketch:

• 1 a highly stylized engine layout in side section with sealing arrangement,
• 2 a concrete engine arrangement in a perspective oblique view with the cover removed and without a control unit,
• 3 the more stylized engine layout 1 when putting on the lid in an oblique view.

1 shows a motor arrangement 2 according to the invention. This contains an electric motor 4 and an electric control unit 6 for controlling the motor 4, here a motor control unit MCU in circuit board form. The motor arrangement 2 is housed in a housing 8 as a whole or has such a housing. In the example, the housing is made of polyphthalamide. The housing 8 contains a motor section 10, in which the motor 4 is accommodated, and a receiving section 12 with a receiving space 14 for the control unit 6. The receiving space 14 is sealed off from the motor section 10 and the environment 16. In the area 16 there is gear oil that is not shown here.

The receiving section 12 contains a lower part 18 which delimits the receiving space 14 to such an extent that only one opening 20 remains free, through which the control unit 6 is introduced into the receiving space 14 when the motor assembly 2 is assembled. The receiving section 12 also contains a cover 22, in the example made of aluminum, which tightly closes the opening 20 along an imaginary edge line 24 and can be placed on the lower part 18 and removed from it, for example to carry out service work on the control unit 6. The edge line 24 runs around or encircles the entire opening 20.

The engine assembly 2 includes a plurality of hold-down devices 26, of which 1 two are visible. This secures the cover 22 in the in 1 shown assembly state M, ie in the mounted state in an assembly direction 50, pressed against the lower part 18. The pressing takes place on a contact surface 28. In the assembled state M, the contact surface 28 is therefore a common surface of corresponding contact structures, here flange parts 30a,b of the cover 22 and the lower part 18. In the example, each of the hold-down devices 26 consists of respective flange parts 30a,b of the cover 22 and the lower part 18 are formed, which are pulled or pressed against one another by a screw connection or a screw 32 .

To seal between the cover 22 and the lower part 18, an in 1 Sealing arrangement 34 shown only symbolically. This has a groove 36 and a tongue 38 lying in the groove 36 in the assembled state M and a sealant 40, here polyacrylate, with all of these components also running along the edge line 24. In 1 the groove 36 is an element of the cover 22 and the tongue 38 is an element of the lower part 18. The groove 36 and the tongue 38 are spaced apart from one another by a gap 42 without contact.

2 FIG. 1 shows the lower part 18, from which the cover 22 is still lifted, in a concretely executed engine arrangement 2, ie not yet in the assembled state M according to FIG 1 located. For clarification, the imaginary edge line 24 encircling the opening 20 is again shown in broken lines. Also here, in an alternative embodiment, the tongue 38 is an element of the cover 22 (not shown) and the groove 36 is an element of the base 18. The edge line 24 runs in the center of the groove 36. The control unit 6 is in 2 Also removed for the sake of clarity, electrical contacts 44 for connection to the control unit 6, which are not explained in detail, are visible, which are designed as bushings 66 through the lower part 18 or the walls, here the floor, of the receiving space 14. In order to form bushings 66, the contacts 44 are cast into the housing 8 on the one hand, and further, not explained in detail here, sealing pans surrounding the contacts 44 are filled with alternative sealant, which is not shown. The passages 66 are sufficiently sealed for the desired tightness requirements of the receiving space 14 . The opening 20 is therefore the only remaining opening of the receiving space 14, which is tightly closed by the single cover 22 with the aid of the sealing arrangement 34.

The edge line 24 and thus the groove 36 delimits an in 2 hatched partially indicated sealing surface 46. The longest possible straight line that is possible here between two points of the edge line 24 represents the transverse extent Q of the sealing surface 46. In the example, the transverse extent Q has a value of 177 mm.

In the example, in relation to the delimited sealing surface 46, the edge line 24 consists exclusively of non-concave sections 54a-h, namely four straight sections 54a-d and four sections 54e-h, each of which has the shape of a segment of a circle. The edge line 24 is therefore in the manner of an in 2 (ideal) quadrilateral 56 indicated only by dashed lines, executed here as a non-square rectangle. It follows the square shape, however, with "rounded corners" in each case in the form of the sections 54e-h. The slight deviation of the straight lines or sections 54a,c and 54b,d, which do not run completely parallel to one another, is still understood here as “rectangular”.

In the example, the radii of curvature of all curved sections 54e-h are each greater than the minimum specified 12.5% of the transverse extent (12.5% of 177 mm is 22.125 mm). Namely, the radius R of the most curved section 54e, and thus the smallest radius of curvature R of the edge line 24, is 22.5 mm here.

2 also shows that exactly six hold-down devices 26 are provided in the example in order to fasten the cover 22 to the lower part 18 . In 2 Only their flange parts 30a are shown in each case, as well as unspecified threaded bushings cast into the flange parts 30a for receiving a respective screw 32 that has not yet been inserted here. The hold-down devices 26 are distributed around the opening 20 and also the sealing arrangement 34, i.e. radially outside this one, arranged.

The distances A1-6 between the respective hold-down devices 26 are those sections of the edge line 24 which are formed between the respective intersection points of the edge line 24 with vertical projection lines 52 of the centers (central axes of the threaded bushings) of the hold-down device 26 .

The length of the smallest section A1 of the edge line 24 is 70 mm here, that of its longest section A4 is 110 mm, the mean value WM of the lengths of all sections A1-6 is 90 mm. The largest deviation D of the lengths of the sections A1-6 from the mean value WM is 20 mm, which corresponds to a maximum deviation D of approx. 22.2%. This means that the maximum permitted deviation D of 22.5% specified here is not exceeded.

As in 2 As can be seen, the hold-down devices 26 serve exclusively to hold the cover 22 on the lower part 18, but not for any other fastening function on the motor assembly 2. Alternative fastening means 58, here a flange with a screw connection, are provided for this purpose. In the example, the fastening means 58 is used to fasten the entire motor assembly 2 to a counterpart 60 that is not explained in detail.

3 shows the lower part 18 again in a highly stylized manner for explanation, from which the cover 22 is still lifted, ie not yet in the assembled state M according to FIG 1 located. For clarification, the imaginary edge line 24 encircling the opening 20 is again shown in broken lines. Here, too, the tongue 38 is an element of the cover 22 and the groove 36 is an element of the lower part 18. A mounting direction 50 describes the direction in which the cover 22 is placed on the lower part 18 during assembly.

The entire motor assembly 2 does not contain any positioning aids in order to place the cover 22 on the lower part 18 along the assembly direction 50 in a precisely positioned manner in a desired position in which a desired gap geometry for the gap 42 is set. Instead, lower part 18 and cover 22 are designed with regard to their contact surfaces 28 in such a way that, in assembly position M, a target penetration depth of tongue 38 into groove 36 is forcibly set, but not a target position of tongue 38 in groove 36 in the plane of the boundary line 24. In other words, there is a game here in two dimensions that in 3 is symbolized by two arrows 64a,b. In other words, the cover 22 can be positioned within certain limits in relation to the lower part 18 in the direction of these two arrows 64a,b. Only the position in the third dimension (here assembly direction 50) is specified via the contact surfaces 28.

The actual or specific positioning is carried out by a mounting device 62 that is different from the motor assembly 2 and is shown in 3 is indicated only schematically. This takes over the adjustment of the cover 22 relative to the lower part 18 in the plane of the edge line 24, ie in the direction of the two arrows 64a, b. The pair of orthogonal arrows 64a,b thus defines a transverse plane to the assembly direction 50.

The mounting direction 50 is the depth direction and axis of symmetry of the groove 36 (based on its cross section).

When the sealant 40 is introduced, it is applied along the edge line 24, here, for example, in the direction of the arrow 70 3 ie circular, filled into the groove 36 or deposited at the bottom of the groove. Due to the rounded shape of the edge line 24, ie the course of the groove 36, a uniform strand of sealant 40 can easily be metered into the groove 36 along the edge line 24.

The part of the housing 8 surrounding the receiving space 14 has no openings whatsoever, with the exception of the bushings 66 of the electrical contacts 44 for connecting the motor 4 and the control unit 6 and a remote station in the vicinity 16, e.g. a power source. Power and/or information/data can be transmitted via the contacts 44 . The bushings 66 of the contacts 44 through the housing 8 are adequately sealed.

Reference List

2

engine arrangement

4

engine

6

control unit

8th

Housing

10

engine section

12

recording section

14

recording room

16

vicinity

18

lower part

20

opening

22

lid

24

edge line

26

hold-down

28

contact surface

30a,b

flange part

32

screw

34

sealing arrangement

36

groove

38

Tongue

40

sealant

42

gap

44

Contact

46

sealing surface

50

mounting direction

52

projection line

54a-h

section (curved / straight)

56

square

58

fasteners

60

counterpart

62

assembly device

64a,b

Arrow

66

execution

70

Arrow

M

assembly condition

R

radius

Q

transverse expansion

A1-6

section (between hold downs)

WM

Average

D

deviation

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 9997980 B2 [0002]

Claims (15)

Motor arrangement (2) with an electric motor (4) and an electric control unit (6) for the motor (4), - with a housing (8), - wherein the housing (8) has a motor section (10) in which the motor (4) is arranged, - wherein the housing (8) has a receiving section (12) which contains a receiving space (14) for the control unit (6), the receiving space (14) being sealed off from the motor section (10) and the environment (16), - wherein the receiving section (12) comprises a lower part (18) which delimits the receiving space (14) and has an opening (10) for inserting the control unit (6) into the receiving space (14), - and the receiving section (12) comprises a removable cover (22) sealing the receiving space (14) tightly, - wherein the receiving section (12) contains a sealing arrangement (34) running along an edge line (24) of the opening (20) and cover (22), - the cover (22) being held in the direction of the lower part (18) via at least one hold-down device (26), - Wherein the receiving section (12) contains a sealing arrangement (34) running along the edge line (24), which in the assembled state (M) has a groove (36) running along the edge line (24) and a tongue (36) lying in the groove (36) 38) and a sealant (40), - wherein the groove (36) is an element of the lower part (18) and the tongue (38) is an element of the cover (22) or vice versa, - wherein the edge line (24) has a radius of curvature (R) at each point which is greater than 5% of the maximum transverse extent (Q) of a sealing surface (46) bounded by the edge line (24). Motor arrangement (2) according to claim 1 , characterized in that the motor arrangement (2) has at least four hold-down devices (26), the hold-down devices (26) being arranged along the edge line (24) and with regard to their distances (A1-6) along the edge line with a deviation (D) of a maximum of 30% based on their mean value (WM) are evenly distributed. Motor arrangement (2) according to one of the preceding claims, characterized in that the opening (20) is the only opening in the receiving space (14) with a cover (22), and otherwise in the receiving space (14) only firmly cast and/or sealed bushings (66) are present through walls of the receiving space (14). Motor arrangement (2) according to one of the preceding claims, characterized in that the edge line (24) with respect to the sealing surface (46) has exclusively non-concave sections (54a-h). Motor arrangement (2) according to claim 4 , characterized in that the edge line (24) is designed in the manner of a square (56) with rounded corners. Motor arrangement (2) according to claim 5 characterized in that the edge line (24) is designed in the manner of a non-square rectangle. Motor arrangement (2) according to one of the preceding claims, characterized in that at least six hold-down devices (26) are provided, which are distributed around the opening (20) in the circumferential direction thereof. Motor arrangement (2) according to claim 7 combined with claim 6 characterized in that two hold-down devices (26) are arranged in the area of each longitudinal side and one hold-down device in each case in the area of each narrow side of the square (56). Motor arrangement (2) according to one of the preceding claims, characterized in that the hold-down device (26) is set up exclusively to hold the cover (22) and lower part (18) together and not to achieve any other fixing function of the motor arrangement (2). Motor arrangement (2) according to one of the preceding claims, characterized in that at least the lower part (18) is made of a polyphthalamide material and/or the cover (22) is made of an aluminum material. Motor arrangement (2) according to one of the preceding claims, characterized in that the lower part (18) and the cover (22) have the same coefficient of thermal expansion with regard to their materials. Motor arrangement (2) according to one of the preceding claims, characterized in that the sealing means (40) consists of a polyacrylate material. Motor arrangement (2) according to one of the preceding claims, characterized in that the motor arrangement (2) has no positioning aid for positioning the cover (22) relative to the lower part (18) in a desired position. A method of assembling an engine assembly (2) according to any one of the preceding claims, wherein: - the cover (22) and at least the base (18) of the rest of the motor arrangement (2) are fixed in an assembly device (62), - the sealant (40) is filled into the groove (36), - the cover (22) in a desired relative position on the lower part with the aid of the assembly device (62). (18) is put on, - the cover (22) is fixed to the lower part (18) with the aid of the hold-down device (26). procedure after Claim 14 , characterized in that before the introduction of the sealant (40) into the groove (36), at least in the area that comes into contact with the sealant (40), the latter is cleaned with the aid of a plasma and/or activated for the sealant (40). becomes.

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