Assembly comprising a support, a part attached to the support and a joint between the support and the part, associated assembly method

Abstract

Assembly comprising a support, a part attached to the support, and a gasket between the support and the part, associated assembly method. The present invention relates to an assembly comprising a support (10), a part attached to the support, and at least two screws (34) for fixing the part to the support. Each screw (34) is inserted through a hole (65) in the part and screwed into a threaded hole (60) in the support along a screw axis (XX). The assembly includes a gasket (33) between the support and the part, the gasket having at least two holes (90) through which the screws pass. The assembly includes at least two rigid bushings (95), each received by a respective hole in the gasket. Each bushing defines a passage through which one of the screws passes. Each bushing has a height along the screw axis less than or equal to the rest thickness of the gasket. The screws are tightened so that the support and the part rest on each bushing. Figure for the abbreviation: Figure 2

Description

Title of the invention: Assembly comprising a support, a part attached to the support and a joint between the support and the part, associated assembly method

[0001] The present invention relates to an assembly of the type comprising a support, a part attached to the support and at least two screws for fixing the part to the support, each engaged through a bore in the part and screwed into a thread in the support along a screwing axis, the assembly comprising a seal between the support and the part, the seal comprising at least two orifices through which the screws pass.

[0002] The present invention also relates to a method of assembling the assembly.

[0003] In rail and road transport vehicles, it is known to fix a box commonly referred to as underbody on a road vehicle chassis or on a bogie of a railway vehicle train using fixing screws.

[0004] The underbody, in the form of a bowl, is held against the surface of the chassis or the bogie by screwing its peripheral collar resting on the surface. The underbody and the chassis then form a sealed space receiving, for example, electrical equipment.

[0005] To make the junction airtight, a seal is inserted between the chassis or the bogie and the underbody collar. The seal is crossed by the fixing screws which are tightened into threads in the chassis or bogie, thus compressing the seal to ensure a tight seal.

[0006] However, maintaining the seal under excessive compression causes the seal to become loose, requiring regular tightening of the fixing screws to maintain the seal of the connection. Such tightening then accentuates the loosening of the seal.

[0007] An aim of the invention is therefore to propose a solution for limiting the fining of the joint while guaranteeing good sealing.

[0008] To this end, the invention relates to an assembly of the aforementioned type, characterized in that the assembly comprises at least two non-deformable rings each received by a respective orifice of the joint, each ring defining a passage crossed by one of the screws, each ring having a height along the screwing axis less than or equal to a thickness at rest of the joint, the screws being tightened so that the support and the added part rest on each ring.

[0009] According to particular embodiments, the assembly comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0010] - each screw comprises a screw head and the assembly further comprises at least one lock washer between the screw head and the part;

[0011] - the support is provided with screw holes, and nuts welded into the extension of the holes, which nuts define the threads into which the screws are screwed;

[0012] - the rings are made of metal;

[0013] - the support and the part respectively define a receiving face and a face each in contact with each ring and the seal, the receiving and supporting faces being substantially flat and substantially parallel to each other;

[0014] - a diameter of each screw is between 5 mm and 10 mm and each passage is circular in section with a diameter between 5.5 mm and 12 mm;

[0015] - a ratio between the thickness at rest of the seal and the height of the ring is included between 1.2 and 1.5; and

[0016] - the support is a railway vehicle chassis, and the part is an underbody of a train of railway vehicles.

[0017] The invention also relates to a method of assembling such an assembly comprising the following steps:

[0018] - positioning the seal against a receiving face of the support so that the the gasket holes are aligned with the threads in the support,

[0019] - placing the part against the seal via a bearing face of the part so that the holes in the part are aligned with the holes in the seal,

[0020] - engagement of each screw through a respective hole in the part, and an orifice respective of the joint,

[0021] - screwing each screw into the thread of the support associated with the orifice and the drilling crossed by said screw,

[0022] the method comprises a step of inserting each ring into one of the orifices of the seal,

[0023] during the engagement step, each screw passes through an orifice of the seal by the passage of the associated ring, and

[0024] during the screwing step, each screw being screwed into the respective thread of the support until the part and the support are respectively in contact with each ring.

[0025] These characteristics and advantages of the invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings, in which: - [Fig.l] [Fig.l] is a perspective view of an assembly comprising a chassis and an underbody of a vehicle, - [Fig.2] [Fig.2] is a section of the whole according to a plane AA comprising the screw axes of the fixing screws of the assembly of [Fig.l], the assembly being assembled, and - [Fig.3] [Fig.3] is a section of the whole of [Fig.2] according to the same AA plan before assembly of the whole.

[0026] A railway vehicle or a road vehicle comprises a chassis 10 on which is fixed a sub-body 15 forming together a sealed box suitable for receiving electrical equipment for example. In the following, the chassis 10 is also called “support” and the sub-body 15 is also called “part”.

[0027] The sub-body 15 has the shape of a trough or bowl and has a collar 16 at its periphery.

[0028] An annular seal 33 of profile identical to that of the collar 16 is interposed between the collar 16 and the chassis 10. Screws 34 ensure the connection of the collar 16 and the chassis 10, and ensure the compression of the seal 33 between them.

[0029] The chassis 10 and the collar 16 of the sub-body 15 are opposite each other via respectively a receiving face 35 for the chassis 10 and a bearing face 40 for the collar 16 of the sub-body 15. The receiving faces 35 and bearing faces 40 are advantageously flat and substantially parallel to each other.

[0030] Along the entire periphery of the collar 16, circular holes 45 are provided in the chassis 10. Each hole 45 passes through the chassis 10 from one side to the other, between the receiving face 35 and an opposite face 50. The holes 45 have an axis XX perpendicular to the receiving face 35. Their diameter is between 4 mm and 11 mm and for example equal to 7 mm.

[0031] The chassis 10 comprises, in the extension of each hole 45, a nut 55. Each nut 55 is preferably welded to the opposite face 50. Each nut 55 is coaxial with the hole 45 associated with it. Each nut 55 defines a thread 60 of the chassis 10 intended to receive a screw 34. The axis XX is therefore a screwing axis.

[0032] The collar 16 of the underbody 15 comprises holes 65 passing through it from the bearing face 40 to an opposing face 70. Each hole 65 of the collar 16 is coaxial with a hole 45 of the chassis 10 and of the same diameter.

[0033] The seal 33 is made of elastomer. It is flat and annular in shape. Its thickness at rest E is between 3 mm and 6 mm and preferably equal to 5 mm.

[0034] The seal 33 is in contact on the one hand with the receiving face 35 of the chassis 10, and on the other hand with the bearing face 40 of the collar 16 of the underbody 15. The seal 33 comprises orifices 90 passing right through it and each opening on the one hand onto the receiving face 35 of the chassis 10, and on the other hand onto the bearing face 40 of the collar 16. Each orifice 90 is coaxial with a hole 45 and a bore 65.

[0035] Each orifice 90 of the seal 33 defines a circular geometry whose diameter is greater than the internal diameters of the bore 65 and the hole 45 associated with it. The diameter of each orifice 90 is generally between 8 mm and 15 mm, and equal to 10 mm in the aforementioned example.

[0036] The assembly comprising the chassis 10, the sub-body 15 and the seal 33, further comprises two rings 95 each received in one of the orifices 90 of the seal 33. Each ring 95 has an external diameter substantially equal to the internal diameter of the orifice 90 associated with it. The central passage 100 is circular and of diameter less than or equal to the diameters of the hole 45 and the bore 65 associated with it. The height H of the ring 95 along the screwing axis XX is less than the thickness at rest E of the seal 33. A ratio between the thickness at rest E of the seal 33 and the height H of each ring 95 is preferably between 1.2 and 1.5.

[0037] Each ring 95 is preferably made of metal.

[0038] The diameter of each central passage 100 is between 5.5 mm and 12 mm, and for example equal to 6.5 mm. The height H of each ring 95 is between 2 mm and 5 mm. In the example where the thickness at rest E of the seal 33 is equal to 5 mm, the height H of each ring 95 is equal to 4 mm.

[0039] When the screws 34 are tightened, each ring 95 is in contact on the one hand with the receiving face 35 of the chassis 10, and on the other hand with the bearing face 40 of the collar 16 by compression of the seal 33.

[0040] The chassis 10 and the underbody 15 are held together, and the joint 33 is held in compression by the fixing screws 34. Each screw 35 is engaged respectively in a bore 65 of the collar 16, a passage 100 of a ring 95, a hole 45 of the chassis 10 and is screwed into the associated nut 55.

[0041] The diameter of each fixing screw 34 is between 5 mm and 10 mm and, in the above-mentioned example, equal to 6 mm.

[0042] The assembly further comprises, for each fixing screw 34, a locking washer 110 and a flat washer 115 between the collar 16 and a head 120 of the screw 34. The locking washer 110 is in contact with the opposing face 70 to the bearing face 40 of the collar 16.

[0043] During assembly, the seal 33 is positioned against the receiving face 35 of the chassis 10 so as to align the orifices 90 of the seal 33 with the holes 45 of the chassis 10.

[0044] Each ring 95 is then inserted into an orifice 90 of the seal 33 and brought into contact with the receiving face 35 of the chassis 10.

[0045] The sub-body 15 is then placed against the seal 33 via the bearing face 40 of its collar 16, so as to align the holes 65 of the collar 16 with the passages 100 of each ring 95.

[0046] Each fixing screw 34, provided with a flat washer 115 and a locking washer 110, is engaged in a bore 65 of the collar 16, in a passage 100 of a ring 95, and in a hole 45 of the chassis 10. The locking washer 110 bears on the opposing face 70 to the bearing face 40 of the collar 16.

[0047] Each fixing screw 34 is then tightened along the nut 55 associated with the hole 45 in which it is engaged until the bearing face 40 is in contact with each ring 95. The collar 16 then compresses the seal 33 via the contact between the bearing face 40 of the collar 16 and the seal 33.

[0048] Thus, the invention makes it possible to limit the compression of the seal 33 and therefore to limit its fining. The invention also makes it possible to limit the deterioration of the seal 33, thus increasing the service life of the seal 33.

[0049] With the assembly according to the invention, the seal is guaranteed by controlled compression of the seal 33.

[0050] In addition, the locking washers 110 make it possible to limit the loosening of the fixing screws 34 and therefore to maintain the sealing and the maintenance of the assembly.

[0051] The production of the rings 95 in metal makes it possible to guarantee that they do not deform following the tightening of each fixing screw 34 in a nut 55.

[0052] The flat geometry of the frame 10 and the collar 16, in particular at the level of the receiving 35 and support 40 faces, makes it possible to guarantee uniform crushing of the seal 33 and therefore good sealing of the connection.

[0053] Furthermore, the production of the threads 60 using nuts 55 welded to the chassis 10 in the extension of the holes 45, makes it possible to simplify the manufacture of the chassis 10. Indeed, the holes 45 in the chassis 10 can be produced without constraint on the diameter of the fixing screws 34 which they will be required to receive. The thread 60 is adjusted to the diameter of each fixing screw 34 received, by the choice of the nut 55 mounted on the chassis 10. This solution is also advantageous compared to a simple nut 55 in the case where the opposite face 50 to the receiving face 35 of the chassis 10 is difficult to access.

Claims

Claims

1. Assembly comprising a support (10), a part (15) attached to the support (10) and at least two screws (34) for fixing the part (15) to the support (10), each engaged through a bore (65) of the part (15) and screwed into a thread (60) of the support (10) along a screwing axis (XX), the assembly comprising a seal (33) between the support (10) and the part (15), the seal (33) comprising at least two orifices (90) crossed by the screws (34), the assembly comprising at least two non-deformable rings (95) each received by a respective orifice (90) of the seal (33), each ring (95) defining a passage (100) crossed by one of the screws (34), each ring (95) having a height (H) along the screwing axis (XX) less than or equal to a thickness at rest (E) of the seal (33), the screws (34) being tightened so that the support (10) and the added part (15) rest on each ring (95),characterized in that the support (10) is provided with holes (45) for the passage of screws (34), and nuts (55) welded in the extension of the holes (45), which nuts (55) define the threads (60) into which the screws (34) are screwed, and in that the support (10) is a railway vehicle chassis, the part (15) being an underbody of a railway vehicle train.,

2. An assembly according to claim 1, characterized in that each screw (34) comprises a screw head (120), and in that the assembly further comprises at least one locking washer (110) between the screw head (120) and the part (15).

3. Assembly according to claim 1 or 2, characterized in that the rings (95) are made of metal.

4. Assembly according to any one of the preceding claims, characterized in that the support (10) and the part (15) respectively define a receiving face (35) and a bearing face (40) each in contact with each ring (95) and the seal (33), the receiving faces (35) and bearing faces (40) being substantially flat and substantially parallel to each other.

5. Assembly according to any one of the preceding claims, characterized in that a diameter of each screw (34) is between 5 mm and 10 mm and in that each passage (100) is circular in section with a diameter between 5.5 mm and 12 mm.

6. Assembly according to any one of the preceding claims, characterized in that a ratio between the thickness at rest (E) of the seal (33) and the height (H) of the ring (95) is between 1.2 and 1.

5.

7. A method of assembling the assembly according to any one of the preceding claims, comprising the following steps: - positioning the seal (33) against a receiving face (35) of the support (10) so that the orifices (90) of the seal (33) are aligned with the threads (60) of the support (10), - placing the part (15) against the seal (33) via a bearing face (40) of the part (15) so that the holes (65) of the part (15) are aligned with the orifices (90) of the seal (33), - engaging each screw (34) through a respective hole (65) of the part (15), and a respective orifice (90) of the seal (33), - screwing each screw (34) into the thread (60) of the support (10) associated with the orifice (90) and the hole (65) crossed by said screw (34), characterized in that the method comprises a step of inserting each ring (95) into one of the orifices (90) of the seal (33), during the engagement step,each screw (34) passes through an orifice (90) of the seal (33) via the passage (100) of the associated ring (95), and during the screwing step, each screw (34) being screwed into the respective thread (60) of the support (10) until the part (15) and the support (10) are respectively in contact with each ring (95).,

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