Housing for a mechanical device, mechanical assembly, gear motor and related attachment method

Abstract

The invention relates to a method for attaching a plastic cartridge (11) intended to guide an output shaft (12) of a mechanical device to a housing (5) of said mechanical device, said housing (5) comprising a chimney (5a) delimited by an upper edge (51) and a base (52), said chimney (5a) being arranged to partially surround the output shaft (12), the plastic cartridge (11) comprising a lateral protrusion (11c), the method comprising at least the following steps: inserting a first end (11a) of said plastic cartridge (11) into the chimney (5a) of said housing (5) until said lateral protrusion (11c) axially abuts against the upper edge (51) of said chimney (5a), deforming at least partially the first end (11a) of said plastic cartridge (11) so as to form an axial abutment.

Description

TECHNICAL FIELD

[0001] The present invention relates to a metal housing for a mechanical device comprising an output shaft and a plastic bushing assembly on the metal housing. The metal housing corresponds for example to a housing for a gear motor, in particular a housing for a wiper device of a motor vehicle. BACKGROUND

[0002] The output shaft of a gear motor of a wiper system, in particular for a wiper system of a rear window of a motor vehicle, generally comprises a relatively long output shaft in order to allow them to pass through the body of the vehicle. It is therefore necessary to use a bushing to guide the shaft, which is attached to the housing of the gear motor containing the reduction gear mechanism.

[0003] The prior art discloses such a bushing, but these components are generally expensive and / or difficult to manufacture or attach to the housing of the gear motor.

[0004] There is therefore a need for a solution to obtain a bushing that is inexpensive and easy to attach to the housing. Furthermore, in order to preserve the service life of the reduction gear mechanism, the assembly of the bushing and the housing must be such that dirt or moisture cannot enter the housing. SUMMARY

[0005] To this end, the present invention relates to a method for attaching a plastic bushing for guiding an output shaft of a mechanical device to a housing of said mechanical device, said housing comprising a chimney delimited by an upper edge and a base, said chimney being arranged to partially surround the output shaft, the plastic bushing comprising a lateral protrusion, the method comprising at least the following steps:

[0006] - inserting a first end of the plastic bushing into the chimney of the housing until the lateral protrusion axially abuts against the upper edge of the chimney,

[0007] - deforming at least partially the first end of the plastic bushing so as to form an axial abutment.

[0008] According to another aspect of the invention, the housing is for example a metal housing or a plastic housing, the hardness of which can be different from the hardness of the plastic of the bushing.

[0009] According to another aspect of the invention, the base of the chimney is at least partially flared towards the inside of the housing and the deforming step comprises flaring the first end of the plastic bushing by plastic deformation.

[0010] According to another aspect of the invention, the deforming step comprises a heating step.

[0011] According to another aspect of the invention, the heating temperature is between 150 and 180°C.

[0012] According to another aspect of the invention, the deforming step comprises a step of applying ultrasonic waves.

[0013] According to another aspect of the application, the plastic cartridge is made of a polyamide which can be filled, for example, with glass fibers.

[0014] According to another aspect of the application, the chimney of the housing comprises at least one recess, and the deforming step comprises deforming the plastic cartridge into said at least one recess so as to form the anti-rotation lug.

[0015] According to another aspect of the application, the mechanical device is a wiper device.

[0016] The application also relates to a housing for a mechanical device, the housing comprising a chimney configured to at least partially surround an output shaft of the mechanical device, the chimney comprising a base having a generally conical inner shape flaring towards the interior of said housing.

[0017] According to another aspect of the application, the housing is a metal housing.

[0018] According to another aspect of the application, the at least one recess is provided in the base of the chimney so as to receive the anti-rotation lug.

[0019] The application also relates to an assembly of a housing and a plastic cartridge as previously described, the plastic cartridge comprising a lateral protrusion forming an abutment and delimiting a first end for insertion into the chimney of the housing surrounding the output shaft.

[0020] According to another aspect of the application, the lateral protrusion is flange-shaped.

[0021] According to another aspect of the application, the flange comprises an end portion curved towards the first end.

[0022] According to another aspect of the application, the flange forms a water deflector to prevent water droplets from entering the housing.

[0023] According to another aspect of the application, the chimney comprises at least a partially annular mating shape configured to cooperate with the lateral protrusion.

[0024] According to another aspect of the application, the first end of the plastic cartridge is flared to cooperate with the flared base of the chimney.

[0025] According to another aspect of the application, the first end of the plastic cartridge is deformed so as to enter the recess and form the anti-rotation lug.

[0026] The application also relates to a gear motor comprising an electric motor, a reduction gear comprising an output shaft, a housing as previously described at least partially housing the electric motor and the reduction gear, and a plastic cartridge forming an assembly with the housing as previously described. BRIEF DESCRIPTION OF DRAWINGS

[0027] Other features and advantages of the present application will appear from the following description, given by way of non-limiting example, with reference to the annexed drawings, in which:

[0028] Figure 1 a schematic perspective view of a gear motor according to the present application is shown,

[0029] Figure 2 a schematic perspective view of a cartridge according to the present application is shown,

[0030] Figure 3 a schematic perspective cross-sectional view of a part of a housing of a gear motor according to the present application is shown,

[0031] Figure 4 a schematic perspective cross-sectional view of an assembly comprising a housing and a cartridge for a gear motor according to the present application is shown,

[0032] Figure 5 , 6 and 7 show schematic perspective cross-sectional views of various assembly steps according to the present application,

[0033] Figure 8 a flow chart showing the various steps of assembling a cartridge on a housing according to the present application.

[0034] In all the figures, identical elements have identical reference signs. DETAILED DESCRIPTION

[0035] The following examples are illustrative. Although described with reference to one or more embodiments, this does not necessarily mean that each reference is referring to the same embodiment, or that features only apply to a single embodiment. Various features of the different embodiments can be combined or interchanged, to provide other embodiments.

[0036] Figure 1 a perspective view of a gear motor 1 for a wiper device of a rear window of a motor vehicle is shown.

[0037] The gear motor 1 comprises an electric motor 3 and a reduction gear mechanism (not shown) arranged in a housing 5 and connected to the electric motor 3. The housing 5 is for example a metal housing or a plastic housing and can comprise for example an attachment tab 7 for attachment to a body element of the vehicle. A silent block 9 can be arranged at the attachment tab 7 for generating a vibration and acoustic decoupling from the body element.

[0038] The gear motor 1 also comprises a barrel 11 made of plastic material for guiding the output shaft 12 of the gear motor 1. The plastic barrel 11 is for example made of polyamide which can be filled or not, i.e. reinforced in particular with glass fibers or any other type of fiber which helps to reinforce the polyamide. In the case where the housing is made of plastic material, the materials of the housing and of the barrel can be different and the hardness of the two materials can be different.

[0039] Figure 2 The barrel 11 is shown separately. The barrel 11 has a general shape of a cylinder and comprises a first end 11a, called inner end, for insertion into the housing 5 at the chimney 5a of the housing 5, and a second end 11b. The barrel 11 also comprises a lateral protrusion 11c which delimits the part of the barrel which is to be inserted into the chimney 5a of the housing 5. The lateral protrusion 11c has a general shape of a flange. The flange can be curved, with a first portion extending in an annular manner around the cylinder, followed by a second portion extending parallel to the barrel 11 towards the first end 11a, the first and second portions being connected by a curved intermediate portion.

[0040] The first end 11a is deformed after being inserted into the chimney 5a of the housing 5 in order to attach the barrel 11 to the housing 5. Thus, Figure 2 The barrel 11 is shown after deformation. Before being inserted into the chimney 5a of the housing 5, the first end 11a has a cylindrical shape (see Figure 5 ).

[0041] As Figure 3 shown, the chimney 5a extends between an upper edge or end portion 51 and a base 52. The upper edge 51 is carried by a cylindrical portion 53 having a first diameter D1. The base 52 comprises a proximal portion 54 having a second diameter D2 which is greater than the first diameter D1, and an expanded intermediate portion 55 for receiving the end portion 11a of the barrel. The upper edge 51 comprises for example a circumferential material recess 57 which is intended to receive the second portion of the lateral protrusion 11c and forms an annular mating shape. The expanded intermediate portion 55 can also comprise one or more recesses 56, for example three recesses, which are provided on a portion of the inner circumference of the chimney 5a and are intended to receive the anti-rotation lugs 110. The recesses 56 can be distributed at regular intervals around the periphery of the chimney 5a. Indeed, as will be better described in the following description, the barrel 11 will be deformed after being inserted into the chimney 5a so that the presence of the one or more recesses 56 causes the first end 11a of the barrel 11 to be deformed in an irregular manner around its circumference, causing the formation of one or more anti-rotation lugs 110 at the one or more recesses 56, thereby preventing any rotational movement of the barrel 11 relative to the chimney 5a. The fact that the chimney 5a is expanded helps to prevent the translation of the barrel 11 by creating an abutment which is created by the lateral protrusion 11c in contact with the upper edge 51 of the chimney 5a.

[0042] Figure 4 The plastic barrel 11 is shown in the assembled state in the chimney 5a of the housing 5, after the first end 11a of the barrel 11 has been deformed so as to form an assembly between the housing 5 and the barrel 11. The lateral protrusion 11c is supported on the upper edge 51 of the chimney 5a and engages in a form-fitting manner around the circumferential material recess 57 provided on the upper edge 51 of the chimney 5a of the housing 5. Thus, the circumferential material recess 57 serves as a mating form for the lateral protrusion 11c of the barrel. By covering the upper edge 51 of the chimney 5a, the lateral protrusion 11c thus forms a moisture deflector which prevents water droplets from entering the connection between the barrel 11 and the housing 5 and contributes to protecting the interior of the housing 5, in particular the reduction gear mechanism.

[0043] The first end 11a of the barrel 11 is in contact with the flared intermediate portion of the chimney and is therefore also flared. Furthermore, the portion of the first end 11a facing the recess 56 is deformed so as to at least partially insert into said recess 56 and form an anti-rotation lug 110.

[0044] Furthermore, the second end 11b of the barrel 11 can comprise a narrower inner portion so as to better guide the output shaft 12 of the gear motor 1. Furthermore, inside its second end 11b, the barrel 11 can comprise a groove 11d for receiving a seal 13, for example an O-ring seal or an overmoulded seal, so as to ensure a tight seal between the barrel 11 and the output shaft of the gear motor 1.

[0045] Thus, in the assembled state, the chimney 5a partially surrounds the barrel 11, i.e. from the first end 11a up to the lateral protrusion 11c of the barrel 11.

[0046] The various steps of the method allowing the assembly and attachment of the plastic barrel 11 onto the housing 5 will now be described with reference to the flowcharts of Figures 5-7 and Figure 8 .

[0047] The first step 101 involves the insertion of the first end 11a of the plastic barrel 11 into the chimney 5a of the housing 5. As shown in Figure 6 , the insertion is continued until the lateral protrusion 11c comes into contact with the end of the chimney. The lateral protrusion 11c is positioned in such a way that, when the lateral protrusion comes into contact with the upper edge 51 of the chimney 5a, the first end 11a of the plastic barrel 11 is opposite the flared intermediate portion 55 of the chimney 5a.

[0048] The second step 102 involves the plastic deformation of the first end 11a of the plastic barrel 11. This deformation corresponds, for example, to flaring the first end against the flared intermediate portion 55 of the chimney 5a so as to form an axial abutment and prevent any translational movement of the plastic barrel 11 relative to the chimney 5a, this abutment being formed by the lateral protrusion 11c supported on the upper edge 51 of the chimney 5a.

[0049] According to a first alternative 102a, the plastic deformation is performed by a step of heating the first end 11a of the plastic barrel 11. In the case of a plastic barrel 11 made of polyamide, which can or can not be filled, the heating temperature is for example between 150°C and 180°C. The deformation can be formed by a conical or substantially conical element inserted into the first end 11a of the plastic barrel 11 from the inside of the housing 5. When the plastic barrel 11 is held in place in the housing 5 (lateral protrusion 11c in contact with the upper edge 51), a pressure is applied to the conical element towards the second end 11b of the plastic barrel 11, causing the first end of the plastic barrel 11 to expand. In the case where the chimney 5a comprises a recess 56, the conical element can comprise a shape complementary to the recess 56, so that the plastic barrel 11 is deformed to fit into the recess 56 and form an anti-rotation lug 110.

[0050] According to a second alternative 102b, the plastic deformation of the first end 11a of the plastic barrel 11 is achieved by a step of applying ultrasonic waves, for example by an ultrasonic welding electrode probe. The application of ultrasonic waves helps to locally heat the first end 11a of the plastic barrel 11, thus making plastic deformation possible. A conical or substantially conical element similar to the conical element of alternative 102a can be used to expand the first end 11a against the expanded middle portion 55 of the chimney 5a of the housing 5. Once the first end 11a of the plastic barrel is expanded, the plastic barrel is attached to the housing and forms an assembly.

[0051] As shown in Figure 7 step 103 comprises positioning a mechanical device (for example a gear motor 1) in the housing 5 and positioning the output shaft 12 of the mechanical device 1 in the plastic barrel 11.

[0052] The application is not limited to a gear motor 1 for a wiper device of a motor vehicle rear window, but extends to other types of mechanical devices comprising an output shaft, a housing and a plastic barrel for guiding the output shaft attached to the housing.

[0053] Thus, the use of a plastic barrel 11 makes it possible to perform the function of guiding the output shaft 12 while limiting the weight and cost of the barrel 11. Furthermore, the attachment of the plastic barrel 11 to the housing 5 is simple and quick and also helps to limit the risk of moisture entering the housing 5, thus protecting the mechanism of the gear motor 1, the housing 5 can be made of a different material than the barrel 11, for example metal.

Claims

1. An attachment method for attaching a plastic cylinder configured to guide an output shaft of a mechanical device to a housing of the mechanical device, the housing including a chimney defined by an upper edge and a base, the chimney being arranged to partially surround the output shaft, the plastic cylinder including lateral protrusions, the attachment method comprising at least the following steps: The insertion step includes inserting the first end of the plastic tube into the chimney of the housing until the lateral protrusion axially abuts against the upper edge of the chimney. The deformation step includes deforming at least partially the first end of the plastic cylinder to form an axial connection; in, The base of the chimney expands at least partially toward the interior of the shell, and the deformation step includes expanding the first end of the plastic cylinder by plastic deformation.

2. The method according to claim 1, wherein, The deformation process includes heating or applying ultrasound.

3. The method according to claim 2, wherein, The deformation step includes a heating step.

4. The method according to claim 1, wherein, The plastic tube is made of polyamide.

5. The method according to claim 1, wherein, The chimney of the housing includes at least one recess, and the deformation step includes deforming the plastic cylinder into the at least one recess (56) to form an anti-rotation lug.

6. The method according to claim 1, wherein, The mechanical device is a gear motor for a wiper assembly.

7. The method according to claim 3, wherein, The heating temperature in the heating step is between 150°C and 180°C.

8. A housing for a mechanical device, including a chimney configured to at least partially surround an output shaft of the mechanical device, the chimney including a base having a generally conical internal shape expanding toward the interior of the housing; A plastic tube, the plastic tube including a lateral protrusion, the lateral protrusion forming an abutment portion and defining a first end; in, The first end is used to insert into the chimney of the housing surrounding the output shaft of the mechanical device; The first end is deformed to expand against the expanded portion of the chimney in order to form an axial connection.

9. The housing according to claim 8, wherein, At least one recess is provided in the base of the chimney of the housing to receive an anti-rotation lug.

10. An assembly of a housing and a plastic cylinder according to claim 8, the plastic cylinder including a lateral protrusion forming an abutment and defining a first end for insertion into a chimney of the housing surrounding the output shaft of the mechanical device.

11. The component of claim 10, wherein, The lateral protrusions are in the shape of flanges.

12. The component of claim 11, wherein, The flange includes a portion that bends toward the first end of the plastic cylinder.

13. The component of claim 10, wherein, The chimney includes at least a partially annular mating shape configured to cooperate with the lateral protrusions.

14. The component of claim 10, wherein, The first end of the plastic cylinder expands to cooperate with the open base of the chimney.

15. A geared motor, comprising: Electric motor; A reduction gear, including an output shaft; the housing according to claim 8, at least partially accommodating the electric motor and the reduction gear; And a plastic tube, which together with the housing forms the assembly according to claim 10.

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