Pinion shaft, gearbox and electrical machine

Abstract

Pinion shaft (1) having a cylindrical main body which has at least one pinion profile (2) on its outside, the pinion shaft (1) being hollow for supplying a lubricant and having at least one opening (7, 10, 11) for a lubricant, wherein the opening (7, 10, 11) is positioned in the pinion profile (2). The pinion shaft (1) can be used in a gearbox (14), which can be connected to an electric machine (13). [Figure 2]

Description

Title of the invention: Pinion shaft, gearbox and electric machine

[0001] The invention relates to a pinion shaft having a cylindrical main body which has at least one pinion profile on its exterior, the pinion shaft being hollow for supplying a lubricant and having at least one opening for a lubricant.

[0002] In general, a pinion shaft is a rotating machine part that transmits motion from one component to another component. Frequently, a pinion shaft is used to transform and adapt torque and rotational speed according to the requirements of a specific application. For example, the rotational speed of an electric motor can be reduced by a pinion shaft in order to drive an axle or a wheel of a vehicle. Furthermore, the torque of an electric motor can be increased by a pinion shaft in order to have sufficient torque for all driving situations and to drive a wheel of a vehicle.

[0003] Usually, the pinion shaft having the pinion profile and other components such as gears must be lubricated with oil in order to reduce friction, wear and noise. The oil, which accumulates in an oil sump, is conveyed by rotating parts to the pinion shaft and other components. Furthermore, hollow pinion shafts have been proposed, so that a lubricant can be supplied through the inside of the pinion shaft, which exits through an opening in the pinion shaft. Nowadays, electric motors that are connected to a gearbox can instantly reach high rotational speeds after being switched on. It is therefore important that a rotating pinion shaft is immediately soaked with oil.

[0004] The invention is therefore based on the problem of providing a pinion shaft with a pinion profile, which can be reliably lubricated with oil over the entire speed range and for a short period of time.

[0005] The problem is solved by a pinion shaft of the aforementioned type, in which the opening for a lubricant is positioned in the pinion profile.

[0006] The invention is based on the fact that a very fast and reliable lubrication of a pinion profile of a pinion shaft can be achieved when the lubricant exits through an opening which is provided directly in the pinion profile itself. Preferably, the lubricant is supplied under pressure. In particular, the lubricant can be supplied by a pump in a closed circuit. In conventional embodiments, an opening is generally provided somewhere in a pinion shaft pinion, for example between two pinion profiles. However, these conventional embodiments have the disadvantage that certain parts of the pinion shaft, in particular the pinion profile, will not be lubricated instantly. When the pinion shaft according to the invention is part of a gearbox which is connected to an electric motor, the pinion profile will be immediately soaked with lubricant when the electric motor is started, since the lubricant comes out of the opening in the pinion profile.

[0007] Preferably, a groove is formed between two adjacent teeth of the pinion profile and the opening is arranged at a groove base (tooth root). In this case, it must be ensured that the tooth root is sufficiently stable to withstand all static and dynamic loads despite the lubricant supply opening.

[0008] However, as a variant, it is also possible for the opening to be arranged at the tip of a tooth of the pinion profile. Such a structure is very stable because the teeth, which are a groove base (tooth root) are not weakened by the opening.

[0009] According to an alternative embodiment of the pinion shaft according to the invention, the opening can also be arranged on a flank of a tooth of the pinion profile.

[0010] The lubricant supply opening may be arranged offset in the axial direction from a central position of the pinion profile. Preferably, the opening is positioned such that it is subjected to only comparatively low loads. However, if required for a specific application, the lubrication opening may also be positioned in a central position of the pinion profile in the axial direction.

[0011] Preferably, a plurality of openings for the lubricant may be arranged adjacent to each other and / or in the circumferential direction and / or in the axial direction. When the pinion shaft has several openings, the amount of lubricant supplied is increased, so that the pinion shaft and the pinion profiles can be soaked instantly after switching on.

[0012] Furthermore, the invention relates to a gearbox, comprising an input shaft and an output shaft, in which at least one of the shafts is a pinion shaft according to the invention as described.

[0013] The invention also relates to an electric machine which is coupled to a gearbox according to the invention.

[0014] The invention is explained with the aid of preferred examples with reference to the drawings. The drawings are schematic representations in which:

[0015] [Fig.l] illustrates a pinion shaft according to the invention;

[0016] [Fig.2] illustrates a detail of a helical pinion profile;

[0017] [Fig.3] illustrates a sectional view of the helical pinion profile;

[0018] [Fig.4] illustrates a second embodiment of a pinion shaft having a helical pinion profile;

[0019] [Fig.5] illustrates a third embodiment of a pinion shaft having a helical pinion profile; and

[0020] [Fig.6] illustrates a vehicle equipped with an electric machine according to the invention.

[0021] [Fig.l] illustrates a cylindrical pinion shaft 1, which is an input shaft of a gearbox that is connected to an electric motor. The pinion shaft 1 is hollow. The outer side of the pinion shaft 1 is provided with pinion profiles 2, 3, 4, the pinion profile 2 being a helical pinion profile, while the pinion profiles 3 and 4 are spline profiles. The helical pinion profile 2 comprises teeth 5 that are positioned in the circumferential direction. A groove (pinion root) 6 is formed between adjacent teeth 5.

[0022] [Fig. 2] is a perspective view and illustrates a detail of the helical pinion profile 2 of the pinion shaft 1. In this embodiment, a lubricant opening 7 is located approximately in the center of the helical pinion profile 2 at a groove base (pinion root).

[0023] [Fig. 3] is a sectional view of the helical pinion profile 2 of the pinion shaft 1. A cylindrical cavity 8 extends inside the pinion shaft 1 in the axial direction. From the cavity 8, a transverse bore 9 branches off in the radial direction of the pinion shaft 1 to the opening 7. A lubricating fluid, in particular oil, is supplied from a pressure pump to the cavity 8 inside the pinion shaft 1. The oil is fed in the axial direction and passes through the transverse bore 9. It exits at the opening 7 and soaks the teeth 5 of the pinion shaft 1. Since the helical pinion profile 2 meshes with another pinion (not shown) of the gearbox, this pinion will also be lubricated by oil.The impulse of the rotating pinion shaft 1 is transmitted to the oil, which is spread and distributed among the teeth 5 of the pinion profile 2 and the teeth of other nearby pinions, so that these pinions are sufficiently lubricated to reduce friction, wear and noise.

[0024] [Fig. 4] is an illustration similar to [Fig. 2] and shows a detail of a second embodiment of a pinion shaft 1. According to the first embodiment, the cylindrical pinion shaft 1 is provided with the helical pinion profile 2 on its outside. The teeth 5 of the helical pinion profile 2 are arranged circumferentially. An opening 10 is located at the tip of a tooth 5 of the helical pinion profile 2. The opening 10 is connected to the cavity 8 inside the pinion shaft 1 via a transverse bore. [Fig. 4] shows that the opening 10 is arranged offset in the axial direction from a central position of the helical pinion profile 2. Accordingly, a lubricating fluid is supplied through the cavity 8 and a transverse bore to the opening 10, where it exits, so that the teeth are lubricated.

[0025] [Fig. 5] illustrates a third embodiment of a pinion shaft 1, which is similar to the embodiments shown in [Fig. 2] and [Fig. 5]. Identical components are therefore not explained in detail again. An opening 11 is located on a flank 12 of the helical pinion profile 2. The opening 11 is connected to the cavity 8 via a transverse bore.

[0026] [Fig. 6] illustrates a vehicle 15 provided with an electric machine 13 provided with the pinion shaft 1, which is an input shaft of a gearbox 14 which is connected to the electric motor 13. A wheel of the vehicle 15 is driven by the electric machine 13 via the gearbox 14.

Claims

Claims

1. Pinion shaft (1) having a cylindrical main body which has at least one helical pinion profile (2) on its outside, the pinion shaft (1) being hollow for supplying a lubricant and having at least one opening (7, 10, 11) for a lubricant, positioned in the pinion profile (2), characterized in that the opening (7, 10, 11) is arranged at the tip of a tooth (5) of the pinion profile (2), offset in the axial direction from a central position of the pinion profile (2).

2. A pinion shaft according to claim 1, wherein a plurality of lubricant openings (7, 10, 11) are arranged adjacent to each other and / or in the circumferential direction and / or in the axial direction.

3. A gearbox (14) comprising an input shaft and an output shaft, wherein at least one of the shafts is a pinion shaft (1) according to one of claims 1 or 2.

4. An electric machine (13) coupled to a gearbox (14) according to claim 3.

Images