阅读说明：本技术 机动车辆旋转电机驱动组件 (Motor vehicle rotating electric machine drive assembly ) 是由 J.夏洛 P-Y.比尔特里斯特 H.德里安 D.马格丽特 E.乔泽福维兹 S.佩雷奥特 于 2018-06-27 设计创作，主要内容包括：本发明涉及一种机动车辆旋转电机(100)驱动组件,该驱动组件包括沿纵向轴线(X)延伸的转子轴(2)和在轴与扭矩传递系统(4)之间提供连接的连接件,该扭矩传递系统(4)包括用于转子轴通过的孔(41),该驱动组件的特征在于,所述孔包括轴向延伸的第一壁(41a)和与该第一壁轴向对齐地延伸的圆柱形第二壁(41b),并且所述转子轴包括：-第一表面(21),其轴向延伸并且与孔的第一壁配合,以使连接件绕转子轴定心；以及-第二圆柱形表面(22),其轴向延伸并且设置有滚花,该滚花的直径(A)大于孔的第二壁的直径(A’),该连接件通过滚花压配合到转子轴上。(The invention relates to a motor vehicle rotating electrical machine (100) drive assembly comprising a rotor shaft (2) extending along a longitudinal axis (X) and a connection providing a connection between the shaft and a torque transmission system (4), the torque transmission system (4) comprising a bore (41) for the passage of the rotor shaft, the drive assembly being characterized in that said bore comprises a first wall (41a) extending axially and a second wall (41b) of cylindrical shape extending axially in alignment with the first wall, and in that said rotor shaft comprises: -a first surface (21) extending axially and cooperating with the first wall of the bore for centering the connection piece about the rotor shaft; and-a second cylindrical surface (22) extending axially and provided with a knurling having a diameter (a) greater than the diameter (a') of the second wall of the bore, the coupling being press-fitted onto the rotor shaft by the knurling.)

1. A motor vehicle rotating electrical machine (100) drive assembly comprising a rotor shaft (2) extending along a longitudinal axis (X) and a connection providing a connection between the shaft and a torque transfer system (4), the torque transfer system (4) comprising a bore (41) for the passage of the rotor shaft, characterized in that the bore comprises a first wall (41a) extending axially and a second wall (41b) of cylindrical shape extending in axial alignment with the first wall, and the rotor shaft comprises:

-a first surface (21) extending axially and cooperating with the first wall of the bore for centering the connection piece about the rotor shaft; and

-a second cylindrical surface (22) extending axially and provided with a knurling having a diameter (a) greater than the diameter (a') of the second wall of the bore, the coupling being press-fitted onto the rotor shaft by the knurling.

2. An assembly according to claim 1, characterized in that the first surface (21) of the rotor shaft (2) and the first wall (41a) of the bore (41) are cylindrical surfaces having the same diameter (B).

3. An assembly according to any one of claims 1 and 2, characterized in that the first surface (21) of the rotor shaft (2) and the first wall (41a) of the bore (41) each exhibit a surface quality comprising irregularities having a size smaller than a characteristic size.

4. An assembly according to any one of claims 2 and 3, characterised in that the connection piece (4) is mounted at the location of the first end of the rotor shaft (2) and that the diameter (B) of the first surface (21) of the rotor shaft is greater than the diameter (A) of the knurling arranged between the first surface and the first end of the rotor shaft.

5. Assembly according to claim 4, characterized in that the diameter (B) of the first surface (21) of the rotor shaft (2) is in the range of 1 to 2 times the knurled diameter (A).

6. An assembly according to any one of claims 2 and 3, characterised in that the connection piece (4) is mounted at the location of the first end of the rotor shaft (2) and that the diameter (B) of the first surface (21) of the rotor shaft, which is arranged between the knurling and the first end of the rotor shaft, is smaller than the diameter (A) of the knurling.

7. Assembly according to any one of the preceding claims, wherein the first centring surface (21) extends over a length preferably in the range 1 to 3 times the length of the surface (22).

8. Assembly according to any one of the preceding claims, wherein the length over which the knurls extend is preferably in the range of 0.1 to 1 times the diameter of the shaft (2).

9. A rotating electric machine (100), characterized in that it comprises a drive assembly according to any one of claims 1 to 7.

Technical Field

The technical field of the invention is that of rotating electrical machines of motor vehicles equipped with an internal combustion engine, such as alternators or starter-alternators.

The present invention relates to a drive assembly for a rotary electric machine comprising a rotor shaft and a connection member (e.g. a pulley or pinion) providing a connection between the shaft and a torque transmission system (e.g. a belt or chain).

Background

Internal combustion engine motor vehicles are equipped with an alternator, the function of which is to convert the mechanical energy from the engine into electrical energy, in particular for the purpose of charging the battery of the vehicle and of supplying the electrical system on board the vehicle.

An alternator is a rotating electrical machine that includes a shaft on which a pulley is mounted. The pulley is connected by a belt to another pulley mounted on the engine crankshaft. The belt transmits the rotational motion of the crankshaft to the shaft of the alternator.

The pulley is locked in rotation about the shaft, usually by means of a fixing nut. However, the clamping force generated by this means of securing may not be sufficient to keep the pulley integral with the shaft. In fact, when the alternator is in operation, the nut is likely to loosen, especially in the case of pulleys subjected to high torques.

Thus, there appears to be a need for improved rotational locking of the pulley about the shaft.

Disclosure of Invention

The present invention proposes a solution to improve the maintenance of a connection (for example a pulley or a pinion) providing a connection between a shaft and a torque transmission system (for example a belt or a chain), said connection being integrally mounted on the shaft in a rotationally and translationally manner.

A first aspect of the invention relates to a drive assembly for a rotating electrical machine of a motor vehicle, the drive assembly comprising a rotor shaft extending along a longitudinal axis and a connection providing a connection between the shaft and a torque transfer system, the torque transfer system comprising a bore for passage of the rotor shaft, the bore comprising an axially extending first wall and a cylindrical second wall extending in axial alignment with the first wall, and the rotor shaft comprising:

-a first surface extending axially and cooperating with the first wall of the bore for centering the connection piece about the rotor shaft; and

-a cylindrical second surface extending axially and provided with a knurling having a diameter larger than the diameter of the second wall of the bore, the coupling being press-fitted to the rotor shaft by the knurling.

The knurls are formed by a plurality of projections that dig grooves into the bore wall when the coupling is press fit onto the shaft. Thus, by means of the invention, it is possible to ensure, by means of knurling, the rotational locking of the connection on the shaft, while ensuring that the connection is mounted in a centered manner.

The drive assembly according to the first aspect of the present invention may also comprise one or more of the following features, considered alone or according to technically possible combinations:

the first surface of the rotor shaft and the first wall of the bore are cylindrical surfaces having the same diameter;

-the first surface of the rotor shaft and the first wall of the bore each exhibit a surface quality comprising irregularities having a size smaller than the characteristic size;

the connection is mounted at the location of the first end of the rotor shaft and the diameter of the first surface of the rotor shaft is larger than the diameter of the knurls, which are arranged between the first surface and the first end of the rotor shaft;

-the diameter of the first surface of the rotor shaft is in the range of 1 to 2 times the diameter of the knurling;

the connecting piece is mounted at the location of the first end of the rotor shaft, the first surface of the rotor shaft having a diameter smaller than the diameter of the knurls, the first surface being arranged between the knurls and the first end of the rotor shaft.

A second aspect of the invention relates to a rotary electric machine comprising a drive assembly according to the first aspect of the invention.

Drawings

The invention, together with its various applications, may be best understood by referring to the following description taken in conjunction with the accompanying drawings in which:

figure 1 is a partial schematic view in longitudinal section of an embodiment of an alternator according to the invention;

figure 2 is a partially exploded schematic view of a first embodiment of the drive assembly of the alternator of figure 1;

fig. 3 is a partially exploded schematic view of a second embodiment of the drive assembly of the alternator of fig. 1.

The drawings are given by way of indication only and in no way limit the invention.

For purposes of clarity, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Detailed Description

An embodiment of an alternator 100 according to the present invention will now be described with reference to fig. 1. An alternator is a rotating electrical machine configured to convert mechanical energy from an internal combustion engine motor vehicle into electrical energy. According to another embodiment of the invention, the rotating electrical machine may be a starter-alternator.

The alternator 100 comprises a drive assembly comprising a rotor shaft 2 extending along a longitudinal axis X and a connection providing a connection between the shaft and a torque transmission system 4, the torque transmission system 4 being integrally mounted in rotation-translation on the front end of the shaft 2.

The connection is realized in the shown example by a pulley. In this case, the torque transmission system is implemented by a belt.

In a different version, not shown, the connection may be realized by a pinion. In this case, the torque transmission system is implemented by a chain. In the continuation of the description, the example chosen is that of a pulley. It should be understood, however, that the pulley could be replaced with a pinion.

Throughout the description and the claims, the terms "front", "rear", "in front" and "behind" are used to characterize the relative position in the frame of the alternator 100, the front part of the alternator 100 corresponding to the end of the shaft 2 provided with the pulley 4.

The alternator 100 further includes a rotor 6 rotatably integrally mounted on the shaft 2 and a stator (not shown) surrounding the rotor 6. The stator is carried by a housing (not shown) which is rotatably mounted relative to the shaft 2 by means of front and rear ball bearings 71, 72 arranged on either side of the rotor 6.

The shaft 2 comprises a thrust bearing 25 arranged between the rotor 6 and the front bearing 71. The front bearing 71 includes an inner bearing race 71a and an outer bearing race 71b that contact the shaft 2. The inner race 71a of the front bearing 71 is abutted against the thrust bearing 25, and the pulley 4 is tightly abutted against the inner race 71a by the fixing nut 8. The front end of the shaft 2 comprises a recess 9 for receiving a key so that the shaft 2 can be rotationally locked during assembly of the pulley 4.

The internal combustion engine includes a crankshaft capable of rotational motion. Pulley 4 is intended to be rotated by a belt which mechanically connects pulley 4 of alternator 100 to a pulley rotationally integrally mounted on the crankshaft. The rotational movement of the crankshaft is transmitted to the pulley 4, the shaft 2 and the rotor 6, which are mounted rotationally integrally.

Fig. 2 shows a partially exploded schematic view of a first embodiment of a drive assembly of the alternator 100. The pulley 4 comprises a hole 41 for the rotor shaft 2 to pass through.

The bore 41 includes a first wall 41a and a second wall 41b extending in axial alignment with each other. The second wall 41b has a cylindrical shape.

The rotor shaft 2 comprises a first surface 21 and a second surface 22 extending in axial alignment with each other. The second surface 22 extends over the entire circumference of the shaft 2 and has an overall shape complementary to the shape of the second wall 41b of the hole 41. The second surface 22 has a cylindrical shape.

As shown in fig. 2, the second surface 22 is provided with knurls having a diameter a substantially greater than the diameter a' of the second wall 41b of the hole 41. The pulley 4 is press-fitted to the rotor shaft 2 by knurling. In addition to the fixing nut 8, the knurling also contributes to the rotationally translational locking of the pulley 4 on the shaft 2. The knurled diameter a is preferably in the range of 1 to 1.1 times the diameter a' of the second wall 41b of the bore 41.

During assembly of pulley 4 on shaft 2, first surface 21 cooperates with first wall 41a of the bore to center the pulley about shaft 2. Indeed, knurling alone does not properly align the centre of the pulley 4 with the longitudinal axis X corresponding to the axis of rotation of the shaft 2. By means of the cooperation of these centring surfaces, the axis of rotation of the pulley 4 is combined with the axis of rotation of the shaft 2, so that the pulley 4 is not unbalanced.

In the embodiment of fig. 2, the first surface 21 of the shaft 2 and the first wall 41a of the bore 41 have a cylindrical shape. Alternatively of the same diameter B, both the first surface 21 of the shaft 2 and the first wall 41a of the hole 41 may have one or more flat surfaces arranged in a circumferential manner parallel to the longitudinal axis X. In this case, the first surface 21 of the shaft 2 and the first wall 41a of the hole 41 have a longitudinally truncated cylindrical shape, which makes it possible to improve the rotational locking of the pulley 4 on the rotor shaft 2.

The first centring surface 21 extends over a length preferably in the range 1 to 3 times the length of the surface 22. It should be noted that the surface 21 forms a functional guide area between the shaft and the pulley.

The length over which the knurls extend is preferably in the range of 0.1 to 1 times the diameter of the shaft 2.

In the embodiment of fig. 2, the diameter B of the first surface 21 of the shaft 2 is greater than the diameter a of the knurling. The diameter B of the first surface 21 of the rotor shaft is then preferably in the range of 1 to 2 times the diameter B of the knurling. In this case, the knurls are arranged in front of the first surface 21. In a complementary manner, the second wall 41b of the hole 41 is arranged in front of the first wall 41a of the hole 41.

Fig. 3 shows a second embodiment of the drive assembly according to the invention, in which the diameter B of the first surface 21 of the shaft 2 is smaller than the diameter a of the knurling. The diameter a of the first surface of the rotor shaft is then preferably in the range of 0.5 to 1 times the diameter B of the knurling. In this case, the knurls are arranged behind the first surface 21. In a complementary manner, the second wall 41b of the hole 41 is arranged behind the first wall 41a of the hole 41.

Advantageously, both the first surface 21 of the rotor shaft 2 and the first wall 41a of the hole 41 present a surface quality comprising irregularities having a size smaller than the characteristic size. According to an embodiment, the first surface 21 and the first wall 41a are visually free of irregularities. According to another embodiment, the first surface 21 and the first wall 41a are uniform for touch. In other words, first surface 21 of rotor shaft 2 and first wall 41a of bore 41 are configured to be substantially smooth to facilitate centering of pulley 4 on shaft 2.

Of course, the invention is not limited to the embodiments described with reference to the drawings, and alternatives can be considered without departing from the framework of the invention. The first surface 21, which is provided as a shaft of the centering pulley 4, may comprise, in particular, a first portion and a second portion arranged on either side of the knurling. Furthermore, the pulleys may also be replaced by pinions and the torque transmission system by, for example, a chain.