shaft arranged within a non-through bore comprising a means for degassing such a bore.

Abstract

shaft arranged within a non-through bore comprising a means for degassing such a bore. The invention relates to an arrangement (3) comprising a housing (10) comprising a non-through bore (11) including a bottom (12), a guiding means (20) fixed within the bore (11), a shaft (30), the shaft (30) comprising a cylindrical portion (31) at one of its ends, the cylindrical portion (31) comprising a distal face (32) and extending from this distal face (32), the cylindrical portion (31) translating and / or pivoting and / or rotating relative to the guiding means (20), a volume (5) of air and / or gas extending within the bore (11), in particular between the distal face (32) of the cylindrical portion (31) and the bottom (12) of the bore (11) of the housing (10), the shaft (30) being partially filled and comprising a means for degassing (40) the volume (5). Abbreviated figure: fig. 3

Description

Title of the invention: A shaft arranged within a non-through bore comprising a means for degassing such a bore. Technical field of the invention

[0001] The invention relates to an arrangement comprising a shaft equipped with a means for degassing a non-through bore of a housing in which such a shaft is arranged. The invention further relates to a gearbox comprising at least such an arrangement. The invention further relates to a vehicle comprising such a gearbox or such an arrangement. Prior art

[0002] A vehicle, particularly a motor vehicle, generally includes a gearbox. Such a gearbox includes shafts comprising gears and at least one shaft comprising a gear-changing means. Such a gear-changing means generally includes a shift fork for changing the gear in engagement. For this purpose, such a shaft comprising such a shift fork has a sliding pivot joint relative to a housing of such a gearbox.

[0003] Thus, a shaft comprising such a fork is mounted within such a housing. To this end, a guide means for such a shaft is arranged within a blind bore formed in such a housing. Such a guide means is generally a bearing or bushing arranged in the blind bore of the housing. Such a guide means has very little clearance with the shaft in order to ensure precise guidance, which creates an almost watertight volume between the end of such a shaft and the bottom of such a blind bore.

[0004] However, given the temperature differences encountered in a gearbox, as well as the presence of lubricating oil at the bottom of such a casing and / or splashed within such a casing, particularly by splashing, such a volume within a non-through bore fills with air and / or moisture and / or gas. It is therefore necessary to allow such a volume to be emptied, drained, or degassed, in particular to avoid hindering the movement of such a shaft relative to such a guiding means. Presentation of the invention

[0005] The present invention aims to provide an arrangement that overcomes the above drawbacks. In particular, the invention makes it possible to ensure degassing compatible with a significant translational stroke of such a shaft, without modifying such a gearbox housing, which is already highly constrained in terms of bearing dimensions. Summary of the invention

[0006] To achieve this objective, the invention relates to an arrangement comprising: a housing, in particular a housing for a gearbox, the housing comprising a non-through bore including a bottom, a guiding means, in particular of the ring type, in particular of the split ring type, fixed within the bore, a shaft, in particular a shaft including a speed control fork, the shaft comprising a cylindrical portion at one of its ends, the cylindrical portion comprising a distal face and extending from this distal face, the cylindrical portion translating and / or pivoting and / or rotating relative to the guiding means, a volume of air and / or gas extending within the bore, particularly between the distal face of the cylindrical portion and the bottom of the crankcase bore, the shaft being partially filled and comprising a means for degassing the volume.

[0007] The degassing means may extend from the distal face to a cylindrical surface of the shaft adjoining the cylindrical portion.

[0008] The degassing means may include a conduit.

[0009] The degassing means may include an axial hole formed in the distal face and a radial hole made in a cylindrical surface of the shaft adjoining the cylindrical portion, the radial hole opening at least partially into the axial hole.

[0010] The guiding means can extend axially over a length having a first value, and the shaft can translate relative to the guiding means towards the bottom of the bore over a stroke having a second value, the cylindrical portion being able to extend from the distal face of the shaft, or substantially from the distal face, over a total length along the axial direction greater than or equal to the sum of the first value and the second value.

[0011] The second value may be greater than or equal to the first value, in particular the second value may be at least 1.5 times the first value.

[0012] The cylindrical portion of the shaft can have a diameter between 12 mm and 16 mm.

[0013] The radial hole and / or the axial hole may have a diameter less than or equal to 5 mm and greater than or equal to 1 mm.

[0014] The invention further relates to a gearbox, in particular for a motor vehicle, the gearbox comprising at least one arrangement as defined above.

[0015] The invention further relates to a vehicle, in particular a motor vehicle, comprising a gearbox as defined above or at least an arrangement as defined above. Presentation of the figures

[0016] These objects, features and advantages of the present invention will be described in detail in the following description of an embodiment of an arrangement, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0017] Fig. 1 is a schematic view of a motor vehicle according to one embodiment of the invention.

[0018] Fig. 2 is a partial perspective view of a housing comprising an arrangement according to an embodiment of the invention.

[0019] Fig. 3 is a partially cross-sectional view of the arrangement according to the embodiment of the invention.

[0020] Fig. 4 is a detailed cross-sectional view of the arrangement according to the embodiment of the invention, the tree occupying different positions.

[0021] Fig. 5 is a perspective and partial cross-sectional view of a tree of the arrangement along a plane passing through the axis of the tree, according to the embodiment of the invention. Detailed description

[0022] The direction in which a vehicle, particularly a motor vehicle, moves in a straight line is defined as the longitudinal direction X. By convention, the direction perpendicular to the longitudinal direction, located in a plane parallel to the ground, is called the transverse direction Y. The third direction, perpendicular to the other two, is called the vertical direction Z. Thus, a right-handed coordinate system XYZ is used in which X is the longitudinal direction in the front-to-back direction of the vehicle, i.e., directed towards the rear, Y is the transverse direction directed to the right, and Z is the vertical direction directed upwards. The forward direction corresponds to the direction in which the vehicle usually moves in the longitudinal direction and is opposite to the backward direction.

[0023] As illustrated in [Fig.1], a vehicle 1, for example a motor vehicle, includes a gearbox 2. The gearbox 2 includes a casing 10.

[0024] The housing 10 preferably contains gears supported by shafts and gear-changing means adapted to move a gear so that it can mesh with separate gears. Such a gear-changing means preferably comprises a shaft 30 on which a fork 4 is mounted. The fork 4 is preferably fixed to the shaft 30, for example by shrink fitting.

[0025] In [Fig.2], the housing 10 preferably comprises a half housing 15 and a half Casing 16 (partially illustrated). The half-casings 15 and 16 are suitable for assembly, fastening, and interlocking with each other to form casing 10. Preferably, a Bearing 13 is provided in half of the housing 15 and a bearing 14 is provided in half of the housing 16. The housing 10 supports the shaft 30.

[0026] The vehicle, or the gearbox 2, or the casing 10, or one of the half casings, includes at least one arrangement 3.

[0027] More specifically, as illustrated in [Fig.3], the arrangement 3 includes the housing 10. The housing 10 includes a non-through bore 11, for example provided at the level of the half-housing 16. The bore 11 includes a bottom 12, for example a circular bottom 12.

[0028] The arrangement 3 further includes a guiding means 20. Preferably, the guiding means is a cylindrical sliding ring. For example, the ring comprises a sliding material, such as Teflon.

[0029] For example, the ring is split. In this case, the ring includes a slot, for example a slot extending parallel to the axis of the ring or extending helically or not parallel to the axis.

[0030] The guiding means 20 is fixed within the bore 11. For example, the bore 11 itself comprises a bore 17 of larger diameter. For example, a shoulder 18 is provided at the bottom of the bore 17. The guiding means 20 is preferably fitted within the bore 17, for example until it contacts the shoulder 18, thus forming a stop.

[0031] The arrangement 3 further includes the shaft 30. Preferably, as previously seen, the shaft 30 includes a speed control fork 4. The shaft 30 includes a cylindrical portion 31 at at least one of its ends. By "cylindrical portion" is meant a section of the shaft 30 intended to be, or to come into, contact with the guiding means, in particular during translations of the shaft relative to the guiding means 20. Thus, the cylindrical portion 31 includes a contact area with the guiding means. More precisely, the cylindrical surface of the portion 31 comes into contact with the internal cylindrical surface of the guiding means. The cylindrical portion 31 may include a distal face 32. The cylindrical portion 31 extends from this distal face 32 to a section 35 perpendicular to the axis A of the shaft 30.

[0032] By "distal face" is meant a surface, in particular a flat or substantially flat surface, extending perpendicularly or substantially perpendicularly with respect to the axis A of the shaft 30. Thus, the distal face 32 of the shaft 30 is a disk, or substantially a disk. For example, the distal face 32 is a disk with a diameter equal to the diameter of the cylindrical portion 31.

[0033] Preferably, the shaft 30 includes a chamfer 34 so that the distal face 32 has a diameter less than the diameter of the cylindrical portion 31. In this case, the cylindrical portion 31 extends from the largest diameter of the chamfer 34 (the diameter of the cylindrical portion 31) to the section 35.

[0034] Thus, the cylindrical portion 31 translates and / or pivots and / or rotates relative to the guiding means 20.

[0035] The arrangement 3 further includes a volume 5 of air and / or gas extending within the bore 11. More precisely, the volume 5 extends globally between the distal face 32 of the cylindrical portion 31 and the bottom 12 of the bore 11 of the housing 10. In addition, the volume 5 extends between the inner cylindrical surface 19 of the bore 11 and the outer cylindrical surface of the cylindrical portion 31, in particular from the distal face 32 to the guiding means 20. In the case of a chamfer 34 formed on the shaft 30, the volume 5 is even larger.

[0036] The shaft 30 is partially solid and includes a degassing means 40 for the volume 5. By "partially solid", it is understood in particular that it is solid outside the cylindrical portion 31 and outside a section 37 of the shaft 30 comprising a cylindrical surface 33. As illustrated in particular in Figures 3, 4 and 5, the section 37 extends between the section 35 perpendicular to the axis A of the shaft 30 corresponding to the limit of the cylindrical portion 31 and a section 36 perpendicular to the axis A of the shaft 30. The section 36 is further from the distal face 32 than the section 35.

[0037] Preferably, the degassing means 40 extends from the distal face 32 to the cylindrical surface 33 of the section 37. In other words, the degassing means 40 opens into the cylindrical surface 33 of the section 37 extending between the section 35 and the section 36. Thus, the degassing means 40 is, for example, a channel extending between the distal face 32 and the cylindrical surface 33.

[0038] Preferably, the degassing means 40 comprises a conduit or nozzle 4L

[0039] In an embodiment not illustrated, the conduit 41 is a single hole, in particular a hole of circular cross-section, extending from the distal face 32 to the cylindrical surface 33 of the section 37. Alternatively, in another embodiment not shown, the degassing means comprises several conduits extending from the distal face 32 to the cylindrical surface 33. For example, each conduit then comprises a single hole, in particular a hole of circular cross-section.

[0040] In the preferred embodiment, illustrated in Figures 3 to 5, the venting means 40, of the conduit type 41, comprises an axial hole 42 formed in, in particular, the distal face 32. The venting means further comprises a radial hole 43 formed in the cylindrical surface 33 of the shaft 30 adjacent to the cylindrical portion 31. The radial hole 43 opens, at least partially, into the axial hole 42. Thus, the holes 42 and 43 are perpendicular or substantially perpendicular to each other. Preferably, the axial hole 42 is coaxial or substantially coaxial with the shaft 30.

[0041] Alternatively, the degassing means comprises a single axial hole 42 and several radial holes arranged at the section 37. The radial holes then open all, at least partially, within the axial hole 42.

[0042] Preferably, the axial hole 42 and the radial hole(s) are of circular cross-section, so that they can be made by drilling for example.

[0043] As illustrated in [Fig. 4], the guide means 20 extends axially over a length L. The length L has a first value. The shaft 30 translates relative to the guide means 20 towards the bottom 12 of the bore 11 over a stroke C along the axial direction of the shaft 30. The stroke C has a second value. Preferably, particularly in the case of a shaft 30 intended to translate, the shaft 30 also translates in the opposite direction to the bottom 12 of the bore.

[0044] As a reminder, the cylindrical portion 31 extends from the distal face 32 (in the absence of a chamfer) of the shaft 30, or from the major diameter of the chamfer 34 if applicable, over a total length LT along the axial direction of the shaft 30. Preferably, the total length LT is greater than, or equal to, the sum of the first and second values. For example, the second value is greater than or equal to the first value, in particular the second value is at least 1.5 times the first value. Alternatively, the second value is less than the first value.

[0045] Thus, particularly in the case of a shaft 30 supporting a gear shift fork in a gearbox and intended to translate and pivot slightly around its axis A, the shaft 30 is made to move back and forth in translation. The cylindrical surface of the cylindrical portion 31 is made to be in contact, to slide, with the inner cylindrical surface of the ring 20 over, or substantially over, the total length LT.

[0046] As illustrated in [Fig. 4], when the shaft is translated to its extreme position towards the bottom 12 of the bore 11 (shaft 30 on the right, shown in dashed lines in [Fig. 4]), the volume 5 is minimal. In this position of the shaft 30, the radial hole 43 is positioned to open into the housing 10, i.e., to the left of the half-housing 16 shown in [Fig. 4]. In the other positions resulting from the translations of the shaft 30, the orifice of the degassing means formed on the surface 33 always opens towards the inside of the housing. As a reminder, the orifice(s) of the degassing means are formed in the cylindrical surface 33 of the cylindrical section 37, i.e., a section delimited by the two sections 35 and 36.

[0047] On the one hand, the axial position of the radial hole 43 is defined to ensure constant degassing of the volume 5 regardless of the position of the shaft in the housing bearing. On the other hand, the position of the radial hole 43 is defined so as to limit the length of the axial hole 42.

[0048] For example, the cylindrical portion 31 of the shaft 30, or even the entire shaft 30, has a diameter between 12 mm and 16 mm. Alternatively, the cylindrical portion 31, or even the entire tree, has a diameter less than or equal to 12 mm, or greater than or equal to 16 mm.

[0049] For example, the radial hole(s) 43, in the case of a circular section, have a diameter less than or equal to 5 mm and greater than or equal to 1 mm. For example, the axial hole 42 has a diameter less than or equal to 5 mm and greater than or equal to 1 mm.

[0050] Note that the cross-sectional area of ​​the shaft at the cylindrical portion 31 and / or the section 37, in particular the outside diameter and the diameter of the nozzle 40, are determined as a function of the radial forces arising from the operation of the gearbox 2.

[0051] For example, the diameter of the cylindrical portion 31 is equal to, or substantially equal to, the diameter of the section 37 having the cylindrical surface 33. In this case, the shaft 30 does not include a step or shoulder, or substantially no step or shoulder, at the section 35 between the cylindrical portion 31 and the adjacent cylindrical surface 33. For example, the diameter of the cylindrical section 37 31 is equal to, or substantially equal to, the diameter of the rest of the shaft extending in the opposite direction to the location of the distal face. Where applicable, the representations of sections 35, 36, in solid or dashed lines, serve only to delineate their locations and not to highlight a difference in diameter.

[0052] In summary, the solution is particularly well-suited to a gearbox, especially for a motor vehicle, for example, a gearbox in a hybrid or electric vehicle. Indeed, the solution facilitates the movement of a shaft comprising a fork, the shaft having a sliding pivot joint relative to a housing.

[0053] The solution is particularly suitable for a Teflon-type sliding ring with very little clearance with the shaft. Since the space between the shaft and the sliding ring is very small (sliding clearance), the ring extends radially, either fully or substantially fully, between the shaft and the bore 11. Thus, no gas can escape or enter the volume 5 except through the conduit 4L.

[0054] More specifically, the solution allows the volume 5 within a non-through bore comprising a bushing 20 to be ventilated and degassed. Indeed, although the bushing 20, for example made of Teflon, does not allow gas and / or air and / or vapor to pass between its bore and the shaft 30 that the bushing guides, the degassing means 40 prevents any increase in pressure in the volume 5. As a reminder, such a bushing has very little play with the shaft in order to ensure quality guidance.

[0055] Thus, although the temperature differences encountered by a gearbox, the presence of lubricating oil at the bottom of the casing and / or projected within the casing, for example by splashing, causes the volume 5 within the undisturbed bore 11 to be When the plug fills with air and / or moisture and / or gas, this volume 5 empties easily. This is particularly the case when the shaft moves towards the bottom 12 of the bore 11. During such a movement, the volume 5 contracts, allowing the gases and / or air and / or oil mist to be expelled through the degassing means. Conversely, when the shaft 30 moves in the opposite direction, the volume 5 expands, creating suction and a pressure drop. Thanks to the degassing means 40, this pressure drop is immediately compensated for in volume 5, with the pressure equalizing through the conduit 40 connecting volume 5 to the inside of the gearbox. Furthermore, if the housing includes a venting means, then volume 5 remains at atmospheric pressure or very close to it.

[0056] Furthermore, the solution facilitates the translation of the shaft relative to its guide by drawing in or expelling the contents of volume 5, thereby maintaining pressure equilibrium within the volume with respect to the pressure inside the gearbox. Thus, an increase in pressure within volume 5, which would constrain the shaft's translation towards the bottom 12, cannot occur. Conversely, a decrease in pressure within volume 5, which would constrain the shaft's translation in the opposite direction, cannot occur.

[0057] Advantageously, as illustrated in Figures 3 and 4, the radial hole 43 is oriented vertically, or substantially vertically, downwards, in particular to avoid any intrusion of lubricant and / or dirt into the volume 5.

[0058] The solution aims to modify only the shaft, it can therefore be applied at the level of crowded bearings, for example having little space in the radial direction.

[0059] The solution can also be applied to a bearing intended to hold a shaft in rotation only, so as to avoid an increase in pressure within a non-through bore when inserting the shaft into the guiding means.

[0060] Furthermore, as illustrated in [Fig. 4], the solution is compatible with a retaining means 50 for the positioning of the guiding means 20. Indeed, in some cases, it is necessary to hold the ring 20 in position within the housing so that it does not, over time, move out of its housing due to repeated shaft movements. For example, the retaining means 50 is of the crimping type for the ring 20. In this case, at least one punch stroke, for example three spaced approximately 120 degrees apart, allows the material of the housing to be bent and deformed at the entrance of the bore receiving the ring 20, after the ring has been inserted.

[0061] Note that the addition of the degassing means within the shaft and the fact of opening at the level of a surface not coming into contact with the area of ​​transmission of the forces of the bearing 20 avoids any deformation and / or wear of the guiding means by friction against this degassing means.

[0062] The solution is suitable for a partially solid shaft offering good mechanical strength in bending. Such a shaft can, for example, optionally be pinned and / or receive a ball bearing.

[0063] As a note, the solution achieves the objective of ensuring the degassing of a bottom of a non-through bore compatible with a substantial translational stroke of the shaft held at the level of this bore, without modifying the casing of a gearbox already highly constrained in terms of dimensioning at the level of the bearings, and has the advantage of being able to be applied in other mechanical devices.

Claims

Demands

1. An arrangement (3) comprising: a housing (10), in particular a housing (10) for a gearbox (2), the housing (10) comprising a non-through bore (11) including a bottom (12), a guide means (20), in particular a ring-type guide, in particular a split ring-type guide, fixed within the bore (11), a shaft (30), in particular a shaft (30) including a gear control fork (4), the shaft (30) comprising a cylindrical portion (31) at one of its ends, the cylindrical portion (31) comprising a distal face (32) and extending from this distal face (32), the cylindrical portion (31) translating and / or pivoting and / or rotating relative to the guide means (20), a volume (5) of air and / or gas extending within the bore (11), in particular between the distal face (32) of the portion cylindrical (31) and the bottom (12) of the bore (11) of the housing (10),characterized in that the shaft (30) is partially solid and includes a means for degassing the volume (5), the guiding means (20) extending axially over a length (L) having a first value, and the shaft (30) translating relative to the guiding means (20) towards the bottom (12) of the bore (11) over a stroke (C) having a second value, the cylindrical portion (31) extending from the distal face (32) of the shaft (30), or substantially from the distal face (32), over a total length (LT) along the axial direction greater than or equal to the sum of the first value and the second value, the second value being greater than the first value.

2. Arrangement (3) according to the preceding claim, characterized in that the degassing means (40) extends from the distal face (32) to a cylindrical surface (33) of the shaft (30) adjoining the cylindrical portion (31).

3. Arrangement (3) according to any one of the preceding claims, characterized in that the degassing means (40) comprises a conduit (41).

4. An arrangement (3) according to any one of the preceding claims, characterized in that the degassing means (40) comprises an axial hole (42) formed in the distal face (32) and a radial hole (43) formed in a cylindrical surface (33) of the shaft (30) adjoining the cylindrical portion (31), the radial hole (43) opening at least partially into the axial hole (42).

5. Arrangement (3) according to any one of the preceding claims, characterized in that the cylindrical portion (31) of the shaft (30) has a diameter between 12 mm and 16 mm.

6. Arrangement (3) according to any one of the preceding claims in combination with claim 4, characterized in that the radial hole (43) and / or the axial hole (42) has a diameter less than or equal to 5 mm and greater than or equal to 1 mm.

7. Gearbox (2), in particular for a motor vehicle (1), characterized in that the gearbox (2) comprises at least one arrangement (3) according to one of the preceding claims.

8. Vehicle, in particular motor vehicle (1), characterized in that it comprises a gearbox (2) according to the preceding claim or at least an arrangement (3) according to any one of claims 1 to 6.