Gearbox housing and bicycle with such a gearbox housing

Description

[0001] The present invention relates to a transmission housing and a rolling machine, such as a lawnmower, equipped with such a transmission housing.

[0002] It relates in particular to a transmission housing having a body formed of at least two shells delimiting, in the assembled state by a parting line, a chamber suitable for being at least partially filled with lubricant, this housing being configured to receive, housed at least partially inside the housing, at least one rotating input shaft having a longitudinal axis and an output shaft to which the rotational movement of the or at least one of the input shafts is suitable for being transmitted, this rotating input shaft comprising a so-called driving end accessible from outside the housing to allow the rotational drive of said input shaft and a threaded portion to form a worm gear, said input shaft carrying a bearing comprising an inner ring surrounding said input shaft and a coaxial outer ring and rolling elements disposed between said rings,said bearing being disposed on the input shaft between the threaded portion and the driving end of said input shaft, said housing providing within the enclosure a receiving location for this bearing and a receiving location for the threaded portion.

[0003] Such a transmission housing is known, as illustrated by document FR3 072 432. Housings are also known through documents JP 2005 170132, US 2020 / 355257, and WO 2018 / 015633. There is an ongoing need for this type of housing to improve performance or quality without increasing size or the number of parts.

[0004] One aim of the invention is to provide a transmission housing whose performance and quality are increased without increasing the number of parts of said housing.

[0005] To this end, the invention relates to a transmission housing having a body formed of at least two shells delimiting, in the assembled state, by a parting line, a chamber suitable for being at least partially filled with lubricant, this housing being configured to receive, housed at least partially inside the housing, at least one rotating input shaft having a longitudinal axis and an output shaft to which the rotational movement of the or at least one of the input shafts is suitable for being transmitted, this rotating input shaft comprising a so-called driving end accessible from outside the housing to allow the rotational drive of said input shaft and a threaded portion to form a worm gear, said input shaft carrying a bearing comprising an inner ring surrounding said input shaft and a coaxial outer ring and rolling elements disposed between said rings,said bearing being disposed on the input shaft between the threaded portion and the driving end of said input shaft, said housing providing within the enclosure a receiving location for this bearing and a receiving location for the threaded portion, characterized in that the housing comprises a barrier disposed between said locations, this barrier extending continuously or discontinuously around said input shaft providing a through passage forming the access passage of the input shaft from one location to the other, this barrier being formed in at least two parts, one carried by one of the shells, the other by the other of the shells, each part of the barrier being made in one piece with the associated shell, at least one of the parts of the barrier being shaped to provide one or more deflectors,The deflector, or at least one of the deflectors, is formed at least partially by a surface inclined downwards from the housing body towards the input shaft, when positioned vertically from the input shaft with the bearing extending over the threaded portion of the input shaft. Thanks to this barrier, the sealing quality at the bearing is improved and the risk of lubricant passing through the bearing is reduced. The barrier design allows for improved sealing without the need for an additional seal. The presence of such a barrier limits the projection of lubricant towards the bearing.This projection is favored by the direction of rotation of the worm gear. The presence at the barrier of one or more surfaces inclined towards the input shaft helps to guide the lubricant projections resulting in particular from the rotation of the input shaft towards the input shaft.

[0006] According to one embodiment of the invention, said deflectors of at least one of the barrier parts being two in number and each being formed at least partially by a surface inclined downwards from the body of the housing towards the input shaft, in the vertically positioned state of the input shaft with the bearing extending above the threaded portion of the input shaft, these deflectors have a junction area having a V-shaped profile. The multiplication of inclined surfaces makes it possible to improve the guidance of the lubricant.

[0007] According to one embodiment of the invention, the deflectors of at least one of the barrier portions being two in number and each formed at least partially by a surface inclined downwards from the housing body towards the input shaft, in the vertically positioned position relative to the input shaft with the bearing extending above the threaded portion of the input shaft, these deflectors are not contiguous and one of the deflectors extends at least partially over the other deflector. The non-contiguous design of the deflectors creates a discontinuous barrier, which facilitates the flow of lubricant towards the so-called bottom portion of the housing, which houses the end of the input shaft opposite the driving end of said input shaft.The axial offset of at least part of the deflectors can allow the lubricant to be guided from one deflector to another deflector in the manner of cascading inclined ramps.

[0008] According to one embodiment of the invention, said deflectors of at least one of the barrier parts being two in number and one of the deflectors being formed at least partially by a surface inclined with a downward slope from the body of the housing towards the input shaft in the vertically positioned state of the input shaft with the bearing extending over the threaded portion of the input shaft, the other deflector is formed at least partially by a surface extending orthogonally to the longitudinal axis of the input shaft.

[0009] According to one embodiment of the invention, at least one of the deflectors has, for delimiting the barrier's passage, a circular arc whose center is located on the longitudinal axis of the input shaft. Preferably, each deflector has, for delimiting the barrier's passage, a circular arc such that the passage is circular in orthogonal projection onto a plane perpendicular to the input shaft.

[0010] According to one embodiment of the invention, at least one of the deflectors forms an annular sector, this annular sector which forms part of a disk being delimited by two concentric circular arcs and two radii, one of the circular arcs forming the arc-shaped part of the deflector used to delimit the passage through the barrier, the other circular arc forming a connection zone of the deflector to the body of the housing.

[0011] According to one embodiment of the invention, in the assembled state of the housing shells, the through-hole provided by the barrier, viewed from outside the housing, has a circular or ovoid shape and, in orthogonal projection onto a plane perpendicular to the longitudinal axis of the input shaft, a circumference larger than the circumference of the input shaft. A free space is thus provided between the barrier and the input shaft. This design limits the risk of lubricant flowing towards the bearing.

[0012] According to one embodiment of the invention, the joint plane of the shells passes through the longitudinal axis of the input shaft and extends perpendicularly to the output shaft.

[0013] According to one embodiment of the invention, the barrier has a plane of symmetry coinciding with the joint plane of the shells. This results in a simplicity of manufacture.

[0014] According to one embodiment of the invention, the housing is configured to receive a gear mounted on the output shaft and meshed with the threaded portion of the input shaft. At least a portion of the downward-sloping inclined surface from the housing body towards the input shaft of at least one of the deflectors, when positioned vertically from the input shaft with the bearing extending above the threaded portion of the input shaft, forms a splash guard located between the gear and the bearing and extending in a plane parallel to a plane tangent to said gear. This arrangement allows for the disruption of a portion of the lubricant flow created by the gear under the effect of its rotation and prevents this flow from being projected directly onto the bearing.

[0015] The invention also relates to a rolling machine, such as a lawnmower, characterized in that it is equipped with a transmission box conforming to that described above. Brève description des dessins

[0016] The invention will be better understood upon reading the following description of exemplary embodiments, with reference to the attached drawings in which: [ Fig. 1 ] represents a perspective view of a machine equipped with a transmission housing according to the invention; [ Fig. 2 ] represents an exploded view of a transmission housing showing its constituent parts; [ Fig. 3 ] represents a partial top view of a transmission housing according to the invention, the input shaft having been omitted; [ Fig. 4 ] represents a partially cross-sectional view of a transmission housing according to the invention; [ Fig. 5 ] represents a partial view of the transmission housing of the figure 4 ; Fig. 6 ] represents a partial perspective view of the transmission housing of the figure 4 in the unassembled state of the casing shells; [ Fig. 7 ] represents a partial view of the transmission housing of the figure 6 part of one of the shells having been omitted to see the inside of the transmission housing; Fig. 8 ] represents a partial view of the transmission housing of the figure 4 , part of one of the shells having been omitted to see the inside of the transmission housing; Fig. 9 ] represents a partial cross-sectional view of a transmission housing with contiguous deflectors; [ Fig. 10 ] represents a perspective view of the transmission housing of the figure 9 in the unassembled state of the casing shells; [ Fig. 11 ] represents a perspective view of the transmission housing of the figure 9 with an input shaft, part of one of the shells having been omitted to see the inside of the transmission housing; [ Fig. 12 ] represents a view of the inside of a transmission housing shell; [ Fig. 13 ] represents a perspective view of a transmission housing, with part of one of the shells omitted to show the inside of the transmission housing; Fig. 14 ] represents a perspective view of the inside of the shell of the figure 12 .

[0017] As mentioned above, the transmission housing 1, the subject of the invention, is more particularly intended to be applied to a rolling motor vehicle 21, such as a lawnmower or a snowplow, preferably with a walk-behind driver, although the driver can also be mounted on the vehicle.

[0018] There figure 1 This represents the application of such a transmission housing 1 to a lawnmower. This lawnmower has a rolling chassis, the front wheels of said chassis being drive wheels capable of being rotated by means of the transmission housing 1 of the invention. Alternatively, the transmission housing 1 can also be used to rotate the rear wheels of the machine 21.

[0019] The transmission housing 1 is here a transmission housing 1 made of synthetic material, preferably produced by injection molding. This transmission housing 1 has a body 2 formed of two shells 2A and 2B joined by a parting line shown as P in the figures. Generally, these shells 2A and 2B are held together at least by bonding with a bead of adhesive applied to the parting line. In the assembled state, these shells 2A and 2B define a chamber 3 suitable for being at least partially filled with lubricant such as grease or oil.

[0020] This transmission housing 1 is configured to receive, housed at least partially within the housing 1, at least one rotating input shaft 4 with a longitudinal axis and an output shaft 5 to which the rotational motion of the input shaft 4 is suitable for transmitting. The input shaft 4 is made of metal. This input shaft 4 comprises a driving end 6, accessible from outside the housing 1 to allow the rotational drive of said input shaft 4, and an opposite end housed inside the housing in a bearing of the housing at the level of the portion forming the bottom of the housing 1.

[0021] The driving end 6 is intended to be coupled to a drive element 22 for rotating the input shaft 4. This drive element 22 can be an electric motor, a motorized worm gear as in the example shown, or something else.

[0022] The input shaft 4 further includes a threaded portion 7 arranged inside the transmission housing 1 to form a worm gear. This threaded portion 7 of the input shaft 4 meshes with a toothed wheel 20 housed inside the housing and mounted on the output shaft 5. This toothed wheel 20 may be fixed or can be fixed for rotation with the output shaft 5.

[0023] The output shaft 5 forms the drive shaft for the rotation of the wheels of the machine 21. The rotational movement of the drive element 22 of the input shaft 4 is transmitted to the input shaft 4, which itself, via its threaded portion, transmits the rotational movement to the toothed wheel 20. This wheel, fixed in rotation with the output shaft 5, transmits its rotational movement to the output shaft 5 to enable the rotational drive of the machine's wheels.

[0024] It should be noted that the toothed wheel 20 can be permanently rotationally fixed with the output shaft 5 or can be rotationally fixed with the output shaft 5, for example by axial displacement of the housing 1.

[0025] In the examples shown, the output shaft 5 is arranged orthogonally to the input shaft 4. The joint plane P of the shells 2A, 2B passes through the longitudinal axis of the input shaft 4 and extends perpendicularly to the output shaft 5.

[0026] The input shaft 4 is further equipped with a bearing 8. This bearing 8 can be mounted on the input shaft 4 by means of a tubular body interposed between the bearing 8 and the input shaft 4, as described in patent FR 3 072 432, the tubular body being held rotationally fixed to the input shaft 4 by the bearing 8. This bearing 8 comprises an inner ring 9 surrounding said input shaft 4 and, in the example shown, for example at the figure 4 The tubular body is designed to form a constrictor ring that is press-fitted onto the tubular body, thus securing this tubular body against rotation to the input shaft 4. Of course, any other method of securing the inner ring 9 of the bearing 8 and the input shaft 4 against rotation can be considered without departing from the scope of the invention.

[0027] The bearing 8 further comprises an outer ring 10 coaxial with the inner ring 9 and rolling elements 11, such as balls or needles or the like, arranged between said inner ring 9 and outer ring 10. The outer ring 10 of the bearing 8 is held in a recess in the housing formed by the shells in the assembled state. The bearing 8 is thus arranged on the input shaft 4 between the threaded portion 7 and the driving end 6 of said input shaft 4.

[0028] The transmission housing 1 is configured to provide, within the housing 1, a receiving location 12 for the bearing 8 and a receiving location 13 for the threaded portion 7. To prevent lubricant from accumulating on the bearing surfaces of the bearing 8 and passing through the bearing towards the outside of the transmission housing 1, the transmission housing 1 includes a barrier 14 located between the aforementioned locations 12 and 13. This barrier 14 extends at least partially over the threaded portion 7 of the input shaft 4 when the input shaft 4 is positioned vertically, with the bearing 8 extending over the threaded portion 7 of the input shaft 4. This barrier 14 can take on a wide variety of shapes.

[0029] Regardless of its shape, this barrier 14 extends, continuously or discontinuously, around said entry tree 4, providing a through passage 15 forming the access passage of the entry tree 4 from one location to another.

[0030] This barrier 14 is therefore a barrier surrounding the entry tree 4, delimiting a continuous surface around said entry tree 4, as illustrated in the figure 11 or discontinuous as illustrated in the figure 5 This barrier 14 provides a through passage 15 forming the access passage, that is to say, the passage through which the entry tree 4 moves from one location to the other. This through passage 15 is therefore crossed by the entry tree 4, which thus extends on both sides of the barrier 14.

[0031] This barrier 14 is formed in at least two parts, represented as 16 and 17 in the figures. These two parts are supported, one, represented as 16 by shell 2A, and the other, represented as 17 by the other shell 2B. Each part 16 or 17 of the barrier is made in one piece with the associated shell 2A or 2B. Thus, part 16 of the barrier is made in one piece with shell 2A, while part 17 of the barrier is made in one piece with shell 2B. At least one of the parts 16 or 17 of the barrier is shaped to provide one or more deflectors.

[0032] In the examples shown, the barrier portion 16 carried by the shell 2A is shaped to provide two deflectors shown as 161 and 162 in the figures, while the barrier portion 17 carried by the shell 2B is shaped to provide two deflectors shown as 171 and 172 in the figures. These deflectors can take on a wide variety of shapes. Thus, one of the deflectors of at least one barrier portion, preferably of each barrier portion 16 or 17, is formed at least partially by a surface inclined downwards from the body 2 of the housing 1 towards the input shaft 4 when the shaft is positioned vertically with the bearing 8 extending over the threaded portion 7 of the input shaft 4. This shape allows for the guidance of the gravity flow of the lubricant.

[0033] In the examples shown, the deflectors of at least one, in this case, of each of the barrier parts, are two per barrier part.

[0034] In the example shown in figures 9 à 11 The deflectors 161 and 162 of the barrier part 16 are each formed at least partially by a surface inclined downwards from the body 2 of the housing 1 towards the input shaft 4 when the input shaft 4 is positioned vertically with the bearing 8 extending over the threaded portion 7 of the input shaft. The same applies to the deflectors 171 and 172 of the barrier part 17.

[0035] These deflectors 161 and 162, or 171 and 172, of the same barrier section have a junction zone with a V-shaped profile. Thus, the junction zone of deflectors 161 and 162 of barrier section 16 is shown as 163 in the figures, while the junction zone of deflectors 171 and 172 of barrier section 17 is shown as 173 in the figures. The deflectors 161 and 162 of barrier section 16 are respectively joined to the deflectors 171 and 172 of barrier section 17 in the assembled shell state by their joint plane. This joint plane of the deflectors from one barrier section to another is shown as P1 in the figures.

[0036] It is noted that, in the examples shown, the barrier 14 has a plane P1 of symmetry coinciding with the plane P of joint of the shells 2A and 2B regardless of the embodiment of the deflectors.

[0037] In the example shown in figures 2 à 8 Again, each barrier section 16 or 17 has two deflectors. The deflectors 161 and 162 of barrier section 16 are each formed at least partially by a downward-sloping inclined surface extending from the body 2 of the housing 1 towards the input shaft 4 when the input shaft 4 is positioned vertically, with the bearing 8 extending over the threaded portion 7 of the input shaft 4. The inclined surfaces converge towards each other. These deflectors 161 and 162 are not contiguous, and one of the deflectors extends at least partially over the other. The same is true of the deflectors 162 and 172 of barrier section 17. Thus, in the assembled state of shells 2A and 2B, joined by their joint plane, deflectors 161 and 171 are joined and form an inclined plane. The same is true of deflectors 161 and 172. The two inclined planes extend opposite each other and have different or identical slopes.The two inclined planes, seen in cross-section, form the non-contiguous branches of a V, with one of the branches extending beyond the other branch at the point of the V.

[0038] Finally, the example of figures 12 à 14 This illustrates a case where each barrier part 16 or 17 again has two deflectors. In this embodiment, the deflectors 161 and 162 of the barrier part 16 are formed, at least partially, one, represented in 161 by a surface inclined downwards from the body 2 of the housing 1 towards the input shaft 4 in the vertically positioned position of the input shaft 4 with the bearing 8 extending above the threaded portion 7 of the input shaft 4, the other, represented in 162 in the figures by a surface extending orthogonally to the longitudinal axis of the input shaft 4. The same applies respectively to the deflectors 171 and 172.

[0039] Regardless of the embodiment, at least a portion of the downward-sloping inclined surface from the housing body towards the input shaft of at least one of the deflectors in the vertically positioned state of the input shaft 4 with the bearing 8 extending over the threaded portion 7 of the input shaft 4 forms a splash guard disposed between the toothed wheel 20 and the bearing 8. This splash guard extends in a plane parallel to a plane tangent to said toothed wheel 20.

[0040] Thus, in the examples shown, at least a part of the inclined surface of the deflector 171 of the barrier part 17 and at least a part of the inclined surface of the deflector 161 of the barrier part 16 form an anti-projection screen interposed between the toothed wheel 20 and the bearing 8. These two screens are coplanar in the assembled state of said shells.

[0041] To obtain a generally circular passage 15, each deflector has, for the delimitation of the passage 15 through the barrier 14, a circular arc 18 centered on the longitudinal axis of the input shaft 4. Each deflector has a general annular sector shape. This annular sector, which forms part of a disk, is delimited by two concentric circular arcs. One of the circular arcs forms the circular arc 18 of the deflector used to delimit the passage 15 through the barrier 14; the other circular arc, which may have an imperfect shape to adapt to the shape of the housing body, forms a connection zone 19 between the deflector and the housing body 2. This other circular arc may be more or less rounded depending on the shape of the housing.

[0042] In the assembled state of the shells 2A and 2B of the housing 1, the passage 15 formed by the barrier 14, viewed from outside the housing, has a circular or ovoid shape and, in orthogonal projection onto a plane perpendicular to the longitudinal axis of the input shaft 4, a circumference larger than the circumference of the input shaft 4. This arrangement prevents any contact between the threaded portion 7 of the input shaft 4 and, more generally, between the input shaft 4 and the barrier 14 during the rotation of the input shaft 4.

[0043] The operation of such a transmission housing is similar to that of prior art transmission housings, but the presence of barrier 14 limits lubricant leakage towards the outside of the housing.

Claims

1. A transmission housing (1) comprising a body (2) formed by at least two shells (2A, 2B) that when assembled about a parting line (P) form an enclosure (3) that can be at least partially filled with lubricant, this housing (1) being configured to receive, seated at least partially inside the housing (1), at least one rotary input shaft (4) with a longitudinal axis and an output shaft (5) to which the rotational movement of the or of the at least one of the input shafts (4) can be transmitted, this rotary input shaft (4) comprising a drive end (6) that is accessible from outside the housing (1) to enable said input shaft (4) to be driven in rotation and a threaded portion (7) to form a worm screw, said input shaft (4) having a bearing (8) comprising a coaxial inner ring (9) surrounding said input shaft (4) and a coaxial outer ring (10), and bearing members (11) arranged between said rings (9, 10), said bearing (8) being arranged on the input shaft (4) between the threaded portion (7) and the drive end (6) of said input shaft (4), said housing (1) including a space (12) for receiving this bearing (8) and a space (13) for receiving the threaded portion (7) inside the enclosure (3), characterized in that the housing (1) comprises a barrier (14) arranged between said spaces (12, 13), this barrier (14) extending continuously or discontinuously about said input shaft (4) forming an access passage (15) for the input shaft (4) from one space (12) to the other space (13), this barrier (14) comprising at least two parts (16, 17), one of said parts (16) being carried by one of the shells (2A, 2B) and the other of said parts (17) being carried by the other of the shells (2A, 2B), each barrier part (16, 17) being integral with the related shell (2A, 2B), at least one of the barrier parts (16; 17) being shaped to form one or more deflectors (161, 162; 171, 172), the or at least one of the deflectors (161, 162; 171, 172) being at least partially formed by a surface sloping downwards from the body (2) of the housing (1) towards the input shaft (4), when the input shaft (4) is positioned vertically and the bearing (8) is arranged above the threaded portion (7) of the input shaft (4).

2. The transmission housing (1) as claimed in claim 1, characterized in that there are two such deflectors (161, 162; 171, 172) of at least one of the barrier parts (16; 17), each of said deflectors is formed at least partially by a surface sloping downwards from the body (2) of the housing (1) towards the input shaft (4), when the input shaft (4) is positioned vertically and the bearing (8) is arranged above the threaded portion (7) of the input shaft (4), and these deflectors (161, 162; 171, 172) have a joining zone (163; 173) with a V-shaped profile.

3. The transmission housing (1) as claimed in claim 1, characterized in that there are two such deflectors (161, 162; 171, 172) of at least one of the barrier parts (16; 17), each of said deflectors is formed at least partially by a surface sloping downwards from the body (2) of the housing (1) towards the input shaft (4), when the input shaft (4) is positioned vertically and the bearing (8) is arranged above the threaded portion (7) of the input shaft (4), these deflectors (161, 162; 171, 172) are not joined, and one of the deflectors (161, 162; 171, 172) is arranged at least partially above the other deflector.

4. The transmission housing (1) as claimed in claim 1, characterized in that there are two such deflectors (161, 162; 171, 172) of at least one of the barrier parts (16; 17), one of the deflectors (161, 162; 171, 172) is formed at least partially by a surface sloping downwards from the body (2) of the housing (1) towards the input shaft (4), when the input shaft (4) is positioned vertically and the bearing (8) is arranged above the threaded portion (7) of the input shaft (4), and the other deflector is formed at least partially by a surface extending orthogonally to the longitudinal axis of the input shaft (4).

5. The transmission housing (1) as claimed in one of claims 1 to 4, characterized in that at least one of the deflectors (161, 162; 171, 172) has a circular arc portion (18) centered on the longitudinal axis of the input shaft (4) to delimit the passage (15) through the barrier (14).

6. The transmission housing (1) as claimed in one of claims 1 to 5, characterized in that at least one of the deflectors (161, 162; 171, 172) forms an annular sector, this annular sector, which forms a disk portion, being delimited by two concentric circular arcs and two radiuses, one of the circular arcs forming the circular arc portion (18) of the deflector used to delimit the passage (15) through the barrier (14), and the other circular arc forming a zone (19) for connecting the deflector to the body (2) of the housing (1).

7. The transmission housing (1) as claimed in one of claims 1 to 6, characterized in that, when the shells (2A, 2B) of the housing (1) are assembled, the passage (15) through the barrier (14) has a circular or ovoid shape when viewed from the outside of the housing (1) and, in an orthogonal projection in a plane perpendicular to the longitudinal axis of the input shaft (4), has a circumference larger than the circumference of the input shaft (4).

8. The transmission housing (1) as claimed in one of claims 1 to 7, characterized in that the parting line (P) of the shells (2A, 2B) passes through the longitudinal axis of the input shaft (4) and extends perpendicular to the output shaft (5).

9. The transmission housing (1) as claimed in claim 8, characterized in that the barrier (14) has a plane of symmetry (P1) that coincides with the parting line (P) of the shells (2A, 2B).

10. The transmission housing (1) as claimed in one of claims 1 to 9, characterized in that the housing (1) is configured to receive a gear wheel (20) mounted on the output shaft (5) and meshed with the threaded portion (7) of the input shaft (4), and in that at least a portion of the surface sloping downwards from the body (2) of the housing (1) towards the input shaft (4) of at least one of the deflectors (161, 162; 171, 172), when the input shaft (4) is positioned vertically and the bearing is arranged above the threaded portion of the input shaft (4) forms a splash guard between the gear wheel (20) and the bearing (8) and extends in a plane parallel to a plane tangential to said gear wheel (20).

11. A wheeled vehicle (21) such as a lawnmower, characterized in that it is provided with a transmission housing (1) as claimed in one of claims 1 to 10.