WO2023011907A1

WO2023011907A1 - Drive assembly and vehicle having a drive assembly of this type

Info

Publication number: WO2023011907A1
Application number: PCT/EP2022/070121
Authority: WO
Inventors: Takashi Shigematsu; Michael KLIMENKO; Zhengyu Liu; Takuya Mizobe
Original assignee: Robert Bosch Gmbh
Priority date: 2021-08-06
Filing date: 2022-07-19
Publication date: 2023-02-09
Also published as: DE102021208596A1

Abstract

The invention relates to a drive assembly (10), comprising: - a drive shaft (12); - a coupling element (14); - a connecting device (16) having a connecting element (18); wherein: the connecting element (18) is coupled to the drive shaft (12) for conjoint rotation; the drive shaft (12) can be coupled to the coupling element (14) for conjoint rotation in a connecting process and can be uncoupled from the coupling element in an disconnecting process; in the connecting process, toothing (20) of the connecting element (18) and toothing (22) of the coupling element (14) are brought into mutual interlocking engagement; the toothing (20) of the connecting element (18) and/or the toothing (22) of the coupling element (14) each have at least one tooth (24), more particularly a plurality of teeth (24), with a first end face (26) and a second end face (28), the tooth (24) having a tooth profile with a first portion (30) and a second portion (32), the first portion (30) and the second portion (32) having different shapes. The invention also relates to a vehicle having a drive assembly of this type.

Description

title

Drive arrangement and vehicle with such a drive arrangement

State of the art

The invention relates to a drive arrangement, in particular for a vehicle, having the features of claim 1, and to a vehicle, in particular a motor vehicle, having the features of the independent claim.

In the case of drive arrangements with an electric machine, it is generally provided that these can be coupled to an output element, for example an output shaft, and can be uncoupled from it again. For such a clutch process, it is necessary to coordinate the speeds of the electric machine and the output element. As a rule, the decoupled electrical machine stands still and does not rotate. For the coupling process, the electrical machine must be accelerated to a specific speed. There are different models for such a speed regulation. Different influences such as e.g. B. Friction, speed gradient or rate of change are taken into account in the models.

Such models are described, for example, in DE 102009 055246 A1 and DE 10 2012 003 020 A1.

Disclosure of Invention

The problem on which the invention is based is solved by a drive arrangement, in particular for a vehicle, having the features of claim 1 and a vehicle, in particular a motor vehicle, having the features of the independent claim. Advantageous developments of the invention are specified in the dependent claims. According to the invention, a drive arrangement, in particular for a vehicle, is proposed, comprising a drive shaft. The drive shaft is in particular non-rotatably coupled to a drive, in particular an electric machine (electric motor), or by means of gearing (for example a spur gear stage).

The drive arrangement further includes a coupling element. This can be, for example, a toothing or gear wheel/pinion coupled to an output shaft, an intermediate shaft or a loose wheel arranged on the input shaft.

The drive arrangement also includes a clutch device with a clutch element (e.g. shift sleeve), the clutch element being coupled to the drive shaft in a torque-proof manner. The coupling element is coupled to the drive shaft in a torque-proof manner, in particular by means of a gear wheel arranged on the drive shaft or a guide hub arranged on the drive shaft with teeth. In particular, the coupling element can be displaced axially (ie along the longitudinal direction of the drive shaft or parallel to the central longitudinal axis of the drive shaft).

The drive shaft can be coupled to the coupling element in a torque-proof manner in a coupling process and can be uncoupled from it in a decoupling process. During the coupling process, toothing (in particular internal toothing) of the coupling element and toothing (in particular external toothing) of the coupling element are brought into positive engagement with one another. For this purpose, the coupling element is in particular shifted axially. In particular, the coupling element runs with its internal toothing on a corresponding external toothing of the guide hub or the gear wheel.

The teeth of the coupling element and/or the teeth of the coupling element each have at least one tooth, in particular a plurality of teeth, each with a first end face and a second end face.

The tooth has a tooth profile with a first section and a second section. In the present case, a tooth profile means a symmetrical cross section through the flanks of a tooth. In other words, the tooth profile is a cross section oriented perpendicularly to the front section. Here is the cutting plane spaced from the axis of rotation of the coupling element or the coupling element.

The first section and the second section have a different shape.

During a coupling process, wear occurs on the elements that are coupled to one another. As a result, the geometry of the toothing of the respective elements can be changed, for example by material removal or material deformation. In particular, this has an influence on the coupling behavior of the elements that are coupled to one another. The form of the teeth thus influences the clutch process and thus also the speed regulation.

The coupling time, i.e. the time that elapses during a coupling process, depends on the speed difference between the elements to be coupled with one another. If the speed difference is too small (both in the positive and negative direction of rotation), the coupling time is long. If the speed difference is too great, the teeth of the coupling elements will repel each other and the coupling time will increase. There is therefore a differential speed target range (or a target speed difference or a target speed difference value) in which the clutch time is minimal. It is desirable to minimize the clutch time so that the clutch process does not adversely affect driving comfort, for example.

Due to the wear of the elements that are coupled to one another, the differential speed target range (or the target speed difference) in which the coupling process can be carried out optimally shifts.

In particular, the target rotational speed difference increases with the number of clutch operations carried out (ie with increasing wear), with the minimum clutch time in particular becoming shorter at the same time. In other words, the minimum clutch time during the life of the drive assembly can be further reduced.

It was found within the scope of the invention that above a certain degree of wear or tear, the shift in the differential speed target range (or the target speed difference) becomes insensitive (or less sensitive) to further wear. That's possible also the clutch time can no longer be minimized or only minimally minimized from a certain degree of wear and tear.

In other words, the speed difference target range (or the target speed difference) can be kept essentially constant during the service life of the drive arrangement by means of a toothing with a worn geometry compared to a toothing with an unworn geometry. Correspondingly, a toothing with a worn geometry allows the clutch time to be reduced in comparison to a toothing with an unworn geometry and can be kept essentially constant during the service life of the drive arrangement.

In the present case, a worn geometry means a geometry that is caused by wear and tear (e.g. material removal and/or material deformation, in particular at corners of the toothing) of the parts that are coupled to one another. In the present case, an unworn geometry means a geometry that has not (yet) been impaired or changed by wear.

A geometry of the toothing of the coupling element and/or the toothing of the coupling element is therefore provided in particular, which corresponds to the worn geometry.

According to a further development, the first section can at least partially have a rounded shape, in particular in the direction of the first end face. The first section can have a rounded shape, in particular in the corner areas. This facilitates coupling or decoupling of the toothing.

According to a development, the first section can taper in the direction of the first end face. The tapering of the first section can be designed, for example, in the form of one or more sections (bevels) that are angled relative to one another. This also promotes coupling or decoupling.

According to a development, the first section can have a trapezoidal shape. This can have a positive effect on coupling or decoupling. According to a development, the second section can directly adjoin the first section in the direction of the second end face. In particular, the first section merges into the second section in the direction of the second end face.

According to a development, the second section can taper in the direction of the second end face.

According to a development, the second section can have a trapezoidal shape. In particular, the trapezoidal shape of the second section is different from the trapezoidal shape of the first section. In particular, the second section can taper in the direction of the second end face.

According to a further development, the tooth profile can have a third section which is directly adjacent to the second section in the direction of the second end face. In particular, the second section merges into the third section in the direction of the second end face.

According to a development, the third section can have a rectangular shape.

According to the invention, a vehicle, in particular a motor vehicle, is proposed with a drive arrangement according to the above statements. With regard to the advantages that can be achieved in this way, reference is made to the relevant statements on the drive arrangement. The measures described in connection with the drive arrangement and/or the measures explained below can be used to further refine the vehicle.

An embodiment of the invention will be explained below with reference to the accompanying drawings. Show it:

FIG. 1 shows a schematic representation of a drive arrangement;

Figure 2 is a schematic representation of teeth of a

Coupling element, a coupling element and a guide hub before a coupling operation; FIG. 3 shows a schematic representation of the toothing according to FIG. 2 during the coupling process;

FIG. 4 shows a schematic representation of the toothing according to FIG. 2 after the coupling process;

FIG. 5 shows a schematic representation of a tooth with an unworn toothing geometry;

Figure 6 is a schematic representation of the tooth. 5 with a worn toothing geometry; and

Figure 7 is a schematic representation of the tooth with one of the worn tooth geometry. 6 corresponding gear geometry.

The drive assembly bears the reference numeral 10 in its entirety in FIG.

In the present case, the toothing geometry is explained by way of example using the drive arrangement 10 shown in the figures. The toothing geometry is not limited to the drive arrangement 10 shown, but can also be applied to other drive arrangements with a clutch.

The drive arrangement 10 has a drive shaft 12 in the example. This is coupled to an electrical machine (not shown) via the gear wheel 11 . A loose wheel 13 is arranged on the drive shaft 12 and meshes with a differential (not shown), for example. A coupling element 14 is arranged on the loose wheel 13 and is coupled to the coupling element 14 in a rotationally fixed manner.

In the example, the drive arrangement 10 also has a clutch device 16 with a clutch element 18 . The coupling element 18 has teeth 20 (internal teeth) and the coupling element 14 has teeth 22 (external teeth) (cf. FIGS. 1 and 2). A guide hub 25 with teeth 27 (external teeth) is arranged for rotation on the drive shaft 12 (cf. FIGS. 1 and 2). The coupling element 18 is non-rotatably arranged on the guide hub 25, the (internal) toothing 20 of the coupling element 18 and the (external) toothing 27 of the guide hub 25 being in engagement with one another.

The coupling element 18 is designed to be axially displaceable. In other words, the coupling element 18 can be moved parallel to the central longitudinal axis 28 of the drive shaft 12 . For this purpose, the clutch device 16 has a shift fork 30 in the example, which can be driven or moved axially, ie parallel to the central longitudinal axis 28 of the drive shaft 12, by means of an electric drive 32.

The drive arrangement 10 shown in FIG. 1 is in a state prior to a coupling process (coupling element 14 and coupling element 18 not (yet) coupled to one another).

Figure 2 shows a schematic representation of the toothing 22 of the coupling element 14, the toothing 20 of the coupling element 18 and the toothing 27 of the guide hub 25 before the coupling process. The teeth 20, 22, 27 shown each have a plurality of teeth 24. For the sake of clarity, only one tooth 24 is provided with a reference number.

Before the coupling process, the toothing 20 of the coupling element 18 is arranged at a distance from the toothing 22 of the coupling element 14 .

Figure 3 shows a schematic representation of the teeth 20, 22, 27 according to Figure 2 during the coupling process. In the example, during the coupling process, the shift fork 30 (cf. FIG. 1) pushes the coupling element 18 in the direction of the coupling element 14 (to the left in FIG. 3).

Depending on the speed differential of the clutch member 18 and the clutch member 14, the teeth 20, 22 of the clutch member 18 and the clutch member 14 engage directly or the teeth 20, 22 repel a few times before engaging. It comes in particular at the corners 33 of the teeth 20, 22 to the high Material stress and a corresponding wear or deformation of the material.

The number of repulsions before the toothings 20, 22 engage can depend on the one hand on the speed difference between the clutch element 18 and the coupling element 14 and on the other hand on the toothing geometry.

Figure 4 shows a schematic representation of the teeth 20, 22, 27 according to Figure 2 after the coupling process. The toothing 22 of the coupling element 14 and the toothing 20 of the coupling element 18 are now engaged with one another. The coupling element 14 and the coupling element 18 are thus coupled to one another in a torque-proof manner. In the coupled state, the speeds of the coupling element 14 and the coupling element 18 are the same.

FIG. 5 shows a schematic representation of the tooth 24 (or its tooth profile) of the toothing 20 of the coupling element 18 and/or the toothing 22 of the coupling element 14 with an unworn toothing geometry.

The tooth 24 has a first face 26 and a second face 28 .

In the present case, the tooth 24 has a first section 30 , a second section 32 and a third section 34 . The second section 32 is directly adjacent to the first section 30 and the third section 34 is directly adjacent to the second section 32 .

FIG. 6 shows a schematic representation of the tooth 24 (or its tooth profile) of the toothing 20 of the coupling element 18 and/or the toothing 22 of the coupling element 14 according to FIG. 5 with a worn toothing geometry.

Due to the stress on the material during the coupling process, rounding occurs in particular in the corner regions 33 (cf. FIGS. 5 and 6).

Figure 7 shows a schematic representation of the tooth 24 (or its

tooth profile) with one of the worn tooth geometry. 6 corresponding toothing geometry (however, tooth 24 already has this toothing geometry when new).

The third section 34 of the tooth 24 shown in FIG. 7 is rectangular. The adjoining second section 32 is trapezoidal (tapering in the direction of the second end face 28). The first section 30 adjoining the second section 32 is also trapezoidal (tapering in the direction of the first end face 26).

The clutch process can be optimized by replicating the worn geometry in this way (cf. FIG. 6).

As mentioned above, the repulsion of the toothings 20, 22 of the coupling element 14 and the coupling element 18 during a coupling process depends on the toothing geometry. In the case of the unworn toothing geometry (cf. FIG. 5), in particular due to the initially still angular corner regions 33, more rejection before the engagement of the toothings 20, 22 is to be expected than with the closed toothing geometry (cf. FIG. 6). In other words, the rounded (worn) corner portions 33 of the serrations 20, 22 better slip past each other for engagement. Correspondingly, the toothings 20, 22 of the coupling element 14 and of the coupling element 18 can better engage with one another at a higher differential speed.

By adapting the toothing geometry to a worn geometry, the clutch time can be minimized and kept (essentially) constant over the service life of the drive arrangement.

It is also conceivable that the teeth 24 (or their tooth profiles) of the toothings 20, 22 have the geometry shown in FIG. 6 (with rounded corner areas).

Claims

Expectations

1. Drive arrangement (10), in particular for a vehicle, comprising

- a drive shaft (12)

- a coupling element (14)

- a coupling device (16) with a coupling element (18), the coupling element (18) being coupled to the drive shaft (12) in a rotationally fixed manner,

- wherein the drive shaft (12) can be coupled in a torque-proof manner to the coupling element (14) in a coupling process and can be uncoupled from the latter in a decoupling process,

- wherein during the coupling process a toothing (20) of the coupling element (18) and a toothing (22) of the coupling element (14) are positively engaged with each other,

- the toothing (20) of the coupling element (18) and/or the toothing (22) of the coupling element (14) each having at least one tooth (24), in particular a plurality of teeth (24), each having a first end face (26) and a has a second end face (28),

- wherein the tooth (24) has a tooth profile with a first section (30) and a second section (32),

- wherein the first section (30) and the second section (32) have a different shape.

2. Drive arrangement (10) according to claim 1, characterized in that the first section (30), in particular in the direction of the first end face (26), at least partially has a rounded shape.

3. Drive arrangement (10) according to claim 1 or claim 2, characterized in that the first section (30) tapers towards the first end face (26).

4. Drive arrangement (10) according to any one of the preceding claims, characterized in that the first section (30) has a trapezoidal shape.

5. Drive arrangement (10) according to one of the preceding claims, characterized in that the second section (32) in the direction of the second end face (28) directly adjoins the first section (30).

6. Drive arrangement (10) according to any one of the preceding claims, characterized in that the second section (32) tapers in the direction of the second end face (28).

7. Drive arrangement (10) according to any one of the preceding claims, characterized in that the second section (32) has a trapezoidal shape.

8. Drive arrangement (10) according to any one of the preceding claims, characterized in that the tooth profile has a third section (34) which is directly adjacent to the second section (32) in the direction of the second end face (28).

9. Drive arrangement (10) according to any one of the preceding claims, characterized in that the third section (34) has a rectangular shape.

10. Vehicle, in particular motor vehicle, with a drive arrangement according to claim 9.