Gear wheel - Assembly comprising such a gear wheel
The gear design with axial reliefs covering bearings addresses gear deformations and noise issues in mobility devices, enhancing stiffness and reducing noise levels.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- VALEO EMBRAYAGES SAS
- Filing Date
- 2021-12-31
- Publication Date
- 2026-07-10
Smart Images
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Abstract
Description
Title of the invention: Gear wheel - Assembly comprising such a gear wheel
[0001] The field of the present invention is that of transmission for mobility devices, in particular mobility devices comprising an electric motor and at least one wheel. The present invention is particularly relevant to motor vehicles.
[0002] Such mobility devices are known to include a reducer with several toothed wheels. It is also known that this reducer generates noise, particularly at the resonant frequency.
[0003] It is known that the resonant frequency of gears is a key characteristic for the noise level of transmissions for electric mobility devices. The gears must be sufficiently stiff to avoid operating at resonance. A compromise must be found between the mass of the gearbox and the stiffness of the gears.
[0004] Vibrations generated during the operation of the gearbox can cause deformation of the gears at certain frequencies. Gears typically have a web to connect a tooth to a hub that secures the gear to the shaft. These deformations depend on the geometry of the teeth and the position of the web relative to the hub. There is a need to improve the geometry of the gear and thus anticipate the risk of deformation.
[0005] To meet all or part of these needs, the invention according to a first aspect relates to a gear intended to be mounted on a shaft, said gear comprising a mesh band, connected by a web to a hub, said gear being characterized in that said gear has at least one relief extending in the direction of its wheel axis and arranged to cover at least part of a bearing.
[0006] The relief(s) can be arranged to cover at least half, preferably at least three-quarters or even all, of the bearing. These reliefs cover, for example, the centers of gravity of each of the rollers or balls of the bearing, depending on the type of bearing used.
[0007] According to embodiments, the toothed wheel according to the invention may have alternatively or complementaryly one of the following characteristics: - the disc is solid - the disc has at least one opening, for example between one and ten openings, for example six, seven, eight or nine.
[0008]
[0009]
[0010]
[0011]
[0012] - the veil can extend axially below or beyond the engagement band - the teeth are straight - the teeth are helical - at least one relief is formed on one side of the veil - at least one relief is formed on an inner periphery of the strip of meshing - The gear wheel has a single relief with an annular shape, closed or open. The annular shape may be closed or open depending on the embodiment. It may be cylindrical or not. - The toothed wheel has several reliefs, preferably an odd number of reliefs, in particular three, five or seven reliefs. These are, for example, angularly distributed regularly around the axis of the wheel. According to another aspect, the invention relates to a gear set comprising a toothed wheel as previously described and a shaft fixed in rotation with the toothed wheel. The shaft is, for example, the shaft of an electric motor intended to equip a mobility device. A mobility device can be a motor vehicle, particularly one with electric or hybrid propulsion. It can be an industrial or construction vehicle. A mobility device can be autonomous or not. It can be a so-called light mobility device, such as a bicycle or tricycle. Depending on the embodiment, the gear assembly according to the invention may alternatively or complementaryly have one of the following characteristics: - the gear and the shaft are one piece. In other words, they are made from a single piece of material, notably by pressing, forging or casting. - the gear assembly further comprises a first bearing arranged to support at least part of the shaft, and said relief of the gear wheel covers at least part of the first bearing. - The shaft is supported by a first bearing and a second bearing; the first and / or second bearing is an angular contact bearing. In some variations, at least one of the bearings may be a straight roller bearing, a ball bearing, or any other type of bearing known to those skilled in the art, or even a needle bearing. - The gear assembly also includes a housing. In this application, the term "housing" means any protective enclosure or part of an enclosure intended to house and protect the gear assembly. Such a housing may be, for example, a cover, a half-shell, or a housing base. - the casing has a mounting area designed to absorb the forces of the first bearing.
[0013] Other features, details and advantages of the invention will become clearer upon reading the following description, which is provided by way of example in conjunction with drawings in which:
[0014] - [Fig. 1] is a cross-sectional view of an assembly according to the invention in a first method of implementation,
[0015] - [Fig. 2] is a cross-sectional view of an assembly according to the invention in a second method of implementation,
[0016] - Figures 3 and 4 show cross-sectional variants of the mode of [Fig.2].
[0017] Figure 1 illustrates in cross-section a gear assembly 100 comprising a gear 10 with axis X and a shaft 20 fixedly and rotationally connected to the gear. The gear 10 has a meshing band 1 connected by a web 3 to a hub 5 and a plurality of ridges 33 extending in the direction of the axis X of the gear. The ridges 33 are three in number and evenly distributed around the axis X; in other words, two ridges are separated by an angle of 120°. In the figures, elements common to several embodiments retain the same reference numeral.
[0018] The veil 3 extends along a plane perpendicular to the X axis. The reliefs 33 are formed on one side of the veil 3.
[0019] The meshing band 1 has teeth 11 on the outer periphery of the gear. In the illustrated example, the teeth 11 are helical; in a variant, the teeth may be straight.
[0020] The shaft 20 is supported by a first and a second bearing 31 and 32. The reliefs 33 cover at least half of the bearing 31. The relief 33 shown in cross-section covers the center of gravity G of the rollers 36 of the first bearing 31. In other words, the free end 330 along the X axis of the relief 33 is located, with respect to the web 3, beyond a plane P of the centers of gravity G of the rollers 36 of the first bearing 31.
[0021] Advantageously, in the illustrated example, the first bearing 31 has inclined rollers. The illustrated example also shows a housing 50 of the gear assembly. The housing 50 has a mounting area 53 in which the outer ring 38 of the first bearing 31 is housed. As illustrated, the mounting area 53 is arranged to absorb the forces of the first bearing 31.
[0022] In other examples of the invention, the first bearing 31 comprises straight rollers or is a ball bearing. As in the illustrated example, the reliefs can then extend beyond a plane P of the centers of gravity of the straight rollers or the balls of the first bearing.
[0023] In the other embodiments shown, the same reference numeral is used for analogous elements. The descriptive elements already explained are not repeated systematically, only the specific features of the different examples are detailed.
[0024] Thus, in the illustrated embodiment [Fig. 2], the toothed wheel 10 has a single relief 33. This relief has an annular shape, here circular with axis X. The relief is closed here. In a variant, it can be open, that is to say, have an open annular shape.
[0025] In the embodiment shown, the relief is cylindrical. In an unillustrated variant, the relief has a non-cylindrical annular shape.
[0026] In the illustrated embodiment example [Fig.3] gear wheel 10 has a single relief 33 which completely covers the first bearing 31.
[0027] This includes straight rollers 36. The outer ring 38 of the first bearing is housed in a mounting area 53 of the first bearing 31. The mounting area 53 extends parallel to the X-axis and is located opposite the shaft 20.
[0028] The toothed wheel 10 has a single relief 33. This relief has an annular shape, here circular with axis X. The relief is closed here. In a variant it can be open, that is to say, have an open annular shape.
[0029] Fig. 4 illustrates a toothed wheel having a relief 33 formed on an inner periphery 13 of the mesh band 1.
[0030] In the illustrated examples, the web 3 of the gear 10 is solid. Without departing from the invention, the web 3 may include at least one opening 8.
[0031] The features, variants and different embodiments of the invention can be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive.
Claims
Demands
1. Gear wheel (10) of axis (X), said gear wheel having a mesh band (1), connected by a web 3 to a hub 5, characterized in that said gear wheel has at least one relief (33) extending in the direction of the axis of the wheel and arranged to cover at least part of a bearing to support at least part of a shaft fixed in rotation with the gear wheel.
2. Gear according to claim 1, the at least one relief (33) being arranged to cover at least half, preferably at least three-quarters or even all of the bearing.
3. Gear according to claim 1 or 2, at least one relief (33) being formed on one side of the web (3).
4. Gear according to any one of the preceding claims, at least one relief (33) being formed on an inner periphery of the mesh band (1).
5. Gear according to any one of claims 1 to 4, comprising a single relief (33) having a circular shape, closed or not, of axis (X).
6. Gear according to any one of claims 1 to 4, comprising several reliefs (33), preferably an odd number of reliefs, for example distributed regularly around the axis (X).
7. Gear wheel (10) according to any one of the preceding claims, the web (3) being solid.
8. Gear wheel (10) according to any one of claims 1 to 4, the disc (3) having at least one opening (8).
9. Gear assembly comprising - a toothed wheel (10) according to any one of the preceding claims, - and a shaft (20) fixed in rotation with the toothed wheel.
10. Gear assembly according to the preceding claim, such that the gear (10) and the shaft (20) are one piece.
11. Gear assembly according to claim 9 or 10, further comprising a first bearing (31) arranged to support at least part of the shaft (20), and the relief (33) of the gear (10) covers at least part of the first bearing (31).
12. Gear assembly according to the preceding claim, the first bearing (31) being an angular bearing.
13. Gear assembly according to any one of claims 11 or 12, also comprising a housing (50) having a mounting area (53) arranged to take up the forces of the first bearing.