Coupling device, separating device having such a coupling device, and electric axle having such a separating device

Abstract

The invention relates to a coupling device, having a first coupling element (1) with a first axial toothing system (4) comprising axially projecting first teeth (5) and a second coupling element (10) with a second axial toothing system (13) comprising axially projecting second teeth (14), wherein the two coupling elements (1, 10) are rotatably mounted and, in order to produce a torque-transmitting connection, can be connected to one another by engagement of the first axial toothing system (4) into the second axial toothing system (13), characterized in that the first axial toothing system (4) has first pockets (6) which are formed between the first teeth (5), are delimited radially at least in one direction, and into which the second teeth (14) engage, or in that the second axial toothing system (13) has second pockets (15) which are formed between the second teeth (14), are delimited radially at least in one direction, and into which the first teeth (5) engage.

Description

[0001] P240394

[0002] - 1 -

[0003] Coupling device, disconnecting device with such a coupling device, and e-axis with such a disconnecting device

[0004] The invention relates to a coupling device comprising a first coupling element with a first axial toothing comprising axially projecting first teeth and a second coupling element with a second axial toothing comprising axially projecting second teeth, wherein both coupling elements are rotatably mounted and can be connected to each other to achieve a torque-transmitting connection by the engagement of the first axial toothing with the second axial toothing.

[0005] Such a coupling device serves to establish and, if necessary, release a fixed torque transmission between two mechanical elements, both of which are mounted on rotating bearings and one of which is coupled to a torque-initiating device. An example of such a disconnect device, sometimes also called a disconnect unit, is a disconnect unit integrated into the e-axle of a motor vehicle, which incorporates such a coupling device. This coupling device, actuated by a corresponding actuator, makes it possible to connect and disconnect the e-axle as needed, i.e., to integrate it into or remove it from the drivetrain.

[0006] Such a coupling device typically comprises two coupling elements: a first coupling element with a first axial toothing and a second coupling element with a second axial toothing. The two axial toothings must be brought into axial engagement with each other to achieve a torque-resistant connection. This means that, depending on which coupling element is axially movable, the axial toothing of one coupling element is inserted into that of the other, resulting in a toothed engagement through which the applied torque can be transmitted. With known coupling devices, a noise is sometimes generated when the two coupling elements engage and reach their end stops, due to metal-to-metal or steel-to-steel contact. In other words, approaching the end position or the end stop is accompanied by a noise. This is P240394

[0007] - 2 - is, however, undesirable, not least with regard to NVH behavior (noise - vibration - harshness).

[0008] The invention is based on the problem of specifying an improved coupling device.

[0009] To solve the problem, in a coupling device of the type mentioned at the outset, it is provided according to the invention that the first axial toothing between the first teeth has first pockets formed, at least radially limited in one direction, into which the second teeth engage, or that the second axial toothing between the second teeth has second pockets formed, at least radially limited in one direction, into which the first teeth engage.

[0010] The coupling device according to the invention is characterized by a specific geometry of at least one of the two axial gears. As described, each of the axial gears has a toothed ring comprising first teeth in the case of the first axial gear and second teeth in the case of the second axial gear. According to the invention, at least one of the two axial gears, i.e., either the first or the second axial gear, is provided with a specific pocket geometry comprising a plurality of pockets, with each pocket being formed between two adjacent teeth. Each pocket is designed as a recess extending into the material of the respective coupling element, relative to the plane from which the respective teeth rise. Each pocket is radially bounded in at least one direction, i.e., either radially inwards or radially outwards.Since the teeth run regularly in straight lines and are centered, the pockets run accordingly, and this applies to both the first and second pockets. When the two axial gears engage, if, for example, the first coupling element has pockets, the second teeth of the second coupling element engage between the first teeth and, with increasing axial movement, penetrate deeper and deeper into the pockets until full gear engagement is achieved. During this engagement in the pockets, which extend circumferentially through the tooth flanks and in at least one P240394.

[0011] - 3 -

[0012] Since the radial direction is limited, the medium contained in the pocket must be displaced by the tooth engaging it. In the simplest case, this medium can be air, or alternatively, a fluid such as oil. The fact that the pocket is limited circumferentially and in at least one radial direction necessitates that the air or fluid be forced out of the pocket by the inserted tooth. This creates a damping effect that reduces the engagement and contact movement of the two coupling elements, thereby reducing or even completely eliminating the impact noise when the tooth enters the end stop. If the pockets contain air, there is essentially pneumatic damping; if the pockets contain a fluid such as oil, there is hydraulic damping.

[0013] The coupling device according to the invention therefore allows, in a simple way, the integration of the specific pocket geometry into at least one of the axial teeth and a correspondingly longer axial design of the teeth of the other axial teeth engaging therein, a damping of the engagement and stop movement, combined with a reduction of the stop noise up to an almost noiseless start-up.

[0014] An advantageous embodiment of the invention provides that both the first axial toothing has first pockets and the second axial toothing has second pockets, so that the second teeth engage in the first pockets and vice versa. In this embodiment, both axial toothings are thus provided with a respective pocket geometry, and the first and second teeth are axially extended accordingly so that they can engage reciprocally in the first and second pockets. The volume of the respective medium to be displaced from the pockets is therefore doubled in this embodiment, which further improves the damping.

[0015] As described, the pockets, whether the first or the second pockets, are limited circumferentially by the respective tooth flanks, as well as in a P240394

[0016] - 4 -

[0017] Radial direction. The first and / or second pockets can be closed only at the radially outer or only at the radially inner end. The respective groove-shaped pocket is therefore open only radially outwards or only radially inwards, but otherwise closed laterally.

[0018] In contrast, a particularly advantageous embodiment of the invention provides that the first and / or second pockets are closed at both radial ends. Accordingly, each pocket is closed both circumferentially via the two tooth flanks of the adjacent teeth and in both radial directions, i.e., radially outward and radially inward, so that the pocket is completely closed laterally. This results in the medium, be it air or a fluid, being forced out of the pocket only between the teeth, i.e., quasi-axially, when the respective tooth engages, with the free cross-section through which the medium is forced out decreasing progressively with increasing engagement. This all-around lateral closure of the pockets therefore further improves the damping.

[0019] In this context, it is advantageous if the first and second teeth, as well as the first and second pockets, have a cross-sectional shape resembling an isosceles trapezoid. The teeth taper slightly in cross-section towards the axial free end, and the pockets also taper axially towards their base. This geometry facilitates both the engagement of the teeth and their insertion into the pockets; furthermore, such a geometry is also easier to manufacture.

[0020] The two coupling elements are preferably designed as ring discs or ring sleeves and each comprises a ring section with an axial ring surface on which the first or the second axial toothing is formed. One coupling element can therefore be, for example, a ring sleeve, while the other coupling element is a ring disc. The specific geometry depends on the design of the separating unit, of which such a coupling device is a part. In any case, each coupling element has a ring-shaped ring section with an axial ring surface.

[0021] - 5 - exhibits, on which, on the one hand, the first or second teeth are formed, and on the other hand, the first or second pockets are recessed into the ring disk surface. The formation of the tooth and pocket structures can be achieved, for example, by reshaping the ring section.

[0022] In addition to the coupling device itself, the invention further relates to a disconnect unit for a mechanical system, by means of which two rotating system units can be detachably separated from one another and, of course, reconnected, wherein such a disconnect unit comprises a coupling device of the type described above. Such a disconnect unit is also frequently called a disconnect unit.

[0023] Finally, the invention relates to an e-axle for a motor vehicle, comprising such a disconnect unit.

[0024] The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show:

[0025] Figure 1 shows a perspective view of a first coupling element.

[0026] Figure 2 shows an enlarged partial view of area II from Figure 1.

[0027] Figure 3 shows a perspective partial view, cut away, of the coupling element from Figure 1.

[0028] Figure 4 shows a perspective view of a second coupling element.

[0029] Figure 5 shows an enlarged partial view of area V from Figure 4.

[0030] Figure 6 is a perspective partial view, cut away, of the coupling element from Figure 4, P240394

[0031] - 6 -

[0032] Figure 7 shows a cutaway partial view of the closed coupling device, and

[0033] Figure 8 shows a cutaway partial view along line VIII-VIII in Figure 7.

[0034] Figure 1 shows, as part of a coupling device according to the invention, a first coupling element 1, which is designed as an annular sleeve. It has an annular section 2 with an axial annular surface 3, on which a first axial toothing 4 is formed, extending annularly over the annular surface 3.

[0035] Figure 2 shows an enlarged partial view of the first axial gear teeth 4. These teeth feature a plurality of straight teeth 5 extending towards the center of the first coupling element 1 and spaced equidistantly apart, with a pocket 6 recessed into the annular surface 3 between each tooth 5. Each pocket 6 is designed as an elongated groove, also extending towards the center of the coupling element 1.

[0036] Each groove is bounded circumferentially by the tooth flanks 7 of two adjacent teeth 5. It is further bounded in both radial directions by corresponding shoulders 8, 9, so that each pocket 6 is closed laterally. This geometry is also illustrated in Figure 3. The depth of each pocket 6, relative to the plane of the ring surface 3, corresponds approximately to the height of each tooth 5, relative to the plane of the ring surface 3.

[0037] The first coupling element therefore has a first axial toothing 4, which results from alternately arranged teeth 5 and pockets 6, so that a tooth geometry as well as a pocket geometry is given.

[0038] Figure 4 shows a schematic representation of a second coupling element 10, designed as an annular disk. It also has an annular section 11 with an axial ring surface 12 on which a second axial toothing 13 is formed, extending annularly over the ring surface 12. The second axial toothing 13 is virtually identical in form to the first axial toothing 4, as both interlock via a positive fit. P240394

[0039] - 7 -

[0040] Figure 5 shows an enlarged partial view of the second axial gear 13. This gear also has a multitude of straight second teeth 14 extending towards the center of the second coupling element 10 and spaced equidistantly apart. Here, too, a pocket 15 is formed between each tooth 14, recessed into the annular surface 12. Each pocket 15 is also designed as an elongated groove extending towards the center of the second coupling element 10. Each groove, and thus each pocket 15, is closed circumferentially by the tooth flanks 16 of two adjacent teeth 14. Likewise, each pocket is bounded in both radial directions by corresponding shoulders 17, 18, so that each pocket 15 is laterally closed on the second coupling element 10. This geometry is also illustrated in Figure 6.The depth of each pocket 15, relative to the plane of the ring surface 12, is also approximately equal to the height of each tooth 14, relative to the plane of the ring surface 12.

[0041] The second coupling element also features a second axial toothing 13, which again consists of alternating teeth 14 and pockets 15, thus providing a specific tooth and pocket geometry on this second coupling element as well. The axial toothing 4, 13 can be formed by forming during the manufacture of the metal or steel coupling elements 1, 10.

[0042] In the use of the coupling device comprising the two coupling elements 1 and 10 in a separating unit for a mechanical system, by which two rotating system units can be detachably separated from each other and, conversely, detachably connected to each other, the two axial gear teeth 4, 13 engage axially to create a rotationally fixed connection that allows the transmission of torque. For this purpose, one of the coupling elements is moved axially by an adjusting device or actuator, so that the axial gear teeth 4, 13 are guided into each other. For example, it is assumed that the second axial gear tooth 13 is inserted axially into the first axial gear tooth 4. This results in a reciprocal engagement of the first teeth 5 in the second pockets 15 and the P240394.

[0043] - 8 - second teeth 14 into the first pockets 6. This situation is illustrated in Figures 7 and 8, which show a coupling device 19 according to the invention comprising the two coupling elements 1 , 10.

[0044] Figure 7 shows a section along a radially extending plane through the engagement of a second tooth 14 in a first pocket 6. The tooth 14 is clearly engaged in the pocket 6 in an almost form-fit manner, with each tooth 14 (this also applies to the teeth 5) and each pocket 6 (this also applies to the pockets 15) having a cross-sectional shape resembling an isosceles trapezoid. The engagement is reciprocal, as shown in Figure 8, meaning that the first teeth 5 also engage in the second pockets 15 in a form-fit manner.

[0045] As described, the pockets 6, 15 are bounded on all sides: circumferentially by the respective tooth flanks 7 and 16, respectively, and radially by the shoulders 8, 9 in the case of the first pockets 6, and 17, 18 in the case of the second pockets 15. This means that when a tooth 5 or 14 engages a pocket 15 or 6, the medium contained in the pocket 6 or 15 must be forced out by the tooth 5 or 14. As the axial engagement increases, the free cross-section between the two axial teeth and the pocket boundary decreases. This results in increasing resistance to the axial insertion movement, causing the two axial teeth 4 and 13 to engage smoothly at the end stop, as shown in Figures 7 and 8, thus preventing any significant noise.Depending on the medium contained in the pockets, pneumatic damping can occur in the case of air, and hydraulic damping in the case of a fluid such as oil. P240394.

[0046] - 9 -

[0047] List of reference signs

[0048] 1 coupling element

[0049] 2 Ring section

[0050] 3 Ring area

[0051] 4 Axial gearing

[0052] 5 teeth

[0053] 6 bags

[0054] 7 Tooth flank

[0055] 8 Shoulder

[0056] 9 Shoulder

[0057] 10 coupling element

[0058] 11 Ring section

[0059] 12 ring area

[0060] 13 Axial gearing

[0061] 14 teeth

[0062] 15 bags

[0063] 16 Tooth flank

[0064] 17 Shoulder

[0065] 18 Shoulder

[0066] 19 Coupling device

Claims

P240394 - 10 - Patent claims 1. Coupling device, comprising a first coupling element (1) with a first axial toothing (4) comprising axially projecting first teeth (5) and a second coupling element (10) with a second axial toothing (13) comprising axially projecting second teeth (14), wherein both coupling elements (1, 10) are rotatably mounted and can be connected to each other to effect a torque-transmitting connection by engagement of the first axial toothing (4) with the second axial toothing (13), characterized in that the first axial toothing (4) has first pockets (6) formed between the first teeth (5), which are radially limited at least in one direction and into which the second teeth (14) engage, or that the second axial toothing (13) has second pockets (15) formed between the second teeth (14), which are radially limited at least in one direction and into which the first teeth (5) engage.

2. Coupling device according to claim 1, characterized in that both the first axial toothing (4) has first pockets (5) and the second axial toothing (13) has second pockets (15), so that both the second teeth (14) engage in the first pockets (6) and the first teeth (5) engage in the second pockets (15).

3. Coupling device according to claim 1 or 2, characterized in that the first and / or the second pockets (6, 15) are closed only at the radially outer or only at the radially inner end.

4. Coupling device according to claim 1 or 2, characterized in that the first and / or the second pockets (6, 15) are closed at both radial ends.

5. Coupling device according to one of the preceding claims, characterized in that the first and second teeth (5, 14) as well as the first P240394 - 11 - and the second pockets (6, 15) have a cross-sectional shape in the form of an isosceles trapezoid.

6. Coupling device according to one of the preceding claims, characterized in that the two coupling elements (1, 10) are designed as ring disks or ring sleeves, each comprising a ring section (2, 11) with an axial ring surface (3, 12) on which the first or the second axial toothing (4, 13) is formed.

7. Separating unit for a mechanical system by means of which two rotating system units can be detachably separated from one another, comprising a coupling device (19) according to one of the preceding claims.

8. E-axle for a motor vehicle, comprising a separation unit according to claim 7.

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