Coupling device, disconnecting device with such a coupling device, and e-axle with such a disconnecting device

Abstract

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 achieve 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.

Description

[0001] 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.

[0002] 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.

[0003] 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.However, this is undesirable, not least with regard to NVH (noise, vibration, harshness) behavior.

[0004] The prior art is referred to as GM DE 74 29 446 U, US 2012 / 0285282 A1, AT 5 11 149 A2, DE 698 21 926 T2 and DE 20 2023 102 925 U1, which each disclose coupling devices.

[0005] The invention is based on the problem of specifying an improved coupling device.

[0006] 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.

[0007] 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 in a regular, straight line and are centered on the tooth, the pockets follow a corresponding pattern, and this applies to both the first and second pockets. When the two axial gears engage, if, for example, the first coupling element has the first 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 of the pockets, which are circumferentially bounded by the tooth flanks and radially bounded in at least one radial direction, the medium contained in each pocket must be displaced by the tooth engaging it. In the simplest case, this medium can be air; alternatively, it can be a fluid such as oil.The fact that each 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 against each other, thereby reducing or even completely eliminating the impact noise when running into the end stop. If the pockets contain air, this is essentially pneumatic damping; if the pockets contain a fluid such as oil, this is hydraulic damping.

[0008] 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.

[0009] 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.

[0010] As described, the pockets, whether first or second, are bounded circumferentially by the respective tooth flanks, as well as radially. 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 outward or only radially inward, but otherwise closed laterally.

[0011] 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 increasing engagement, the free cross-section through which the medium is forced out decreases progressively. This all-around lateral closure of the pockets therefore further improves the damping.

[0012] 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.

[0013] The two coupling elements are preferably designed as ring discs or ring sleeves and each comprises a ring section with an axial annular surface on which the first or second axial teeth are 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 annular surface on which, on the one hand, the first or second teeth are formed, and on the other hand, recessed into the ring disc surface, the first or second pockets are formed. The formation of the tooth and pocket structures can be achieved, for example, by forming the ring section.

[0014] 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.

[0015] Finally, the invention relates to an e-axle for a motor vehicle, comprising such a disconnect unit.

[0016] The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show: Fig. 1 a perspective view of a first coupling element, Fig. 2 an enlarged partial view of area II from Fig. 1, Fig. 3 a perspective partial view, cut away, of the coupling element made of Fig. 1, Fig. 4 a perspective view of a second coupling element, Fig. 5 an enlarged partial view of area V from Fig. 4, Fig. 6 a perspective partial view, cut away, of the coupling element made of Fig. 4, Fig. 7 a cutaway partial view of the closed coupling device, and Fig. 8 a sectioned partial view along line VIII-VIII in Fig. 7.

[0017] Fig. Figure 1 shows a first coupling element 1, designed as a ring sleeve, as part of a coupling device according to the invention. It has a ring section 2 with an axial ring surface 3, on which a first axial toothing 4 is formed, extending in a ring shape over the ring surface 3.

[0018] Fig. Figure 2 shows an enlarged partial view of the first axial gear teeth 4. These teeth feature a multitude of straight teeth 5 extending towards the center of the first coupling element 1 and spaced equidistantly apart, with a recess 6 formed in the annular surface 3 between each tooth 5. Each recess 6 is designed as an elongated groove, also extending towards the center of the coupling element 1. 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 recess 6 is closed laterally. This geometry is also illustrated in Figure 2. Fig. Figure 3 shows that 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.

[0019] 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.

[0020] Fig. Figure 4 shows a schematic representation of a second coupling element 10, designed as a ring disk. It also has a ring section 11 with an axial ring surface 12 on which a second axial toothing 13 is formed, which also extends ring-shaped over the ring surface 12. The second axial toothing 13 is virtually identical in form to the first axial toothing 4, since both interlock via a positive fit.

[0021] Fig. 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, with a pocket 15 formed between each tooth 14, which is also 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 clearly illustrated in Fig. Figure 6 shows. 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.

[0022] 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 for this second coupling element as well. The axial toothing 4, 13 can be formed by forming during the manufacturing of the metal or steel coupling elements 1, 10.

[0023] 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, assume 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 of the second teeth 14 in the first pockets 6. This situation is described in the Fig. 7 and Fig. Figure 8 shows a coupling device 19 according to the invention comprising the two coupling elements 1, 10.

[0024] Fig. Figure 7 shows a section along a radially extending cutting 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-fitting 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 Fig. Figure 8 shows, i.e., that of course the first teeth 5 also engage in the second pockets 15 in a form-fitting manner.

[0025] 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 and 9 in the case of the first pockets 6, and 17 and 18 in the case of the second pockets 15. This means that when a tooth 5 or 14 engages a pocket 15 or 6, respectively, the medium contained in the pocket 6 or 15 must be forced out by the tooth 5 or 14. With increasing axial engagement, the free cross-section between the two axial teeth, or between the tooth 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 damped at the end stop, as described in the Fig. 7 and Fig.As shown in Figure 8, the mechanism runs without any significant noise generation. Depending on the medium held in the pockets, pneumatic damping can occur in the case of air, and hydraulic damping in the case of a fluid such as oil.

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 achieve a torque-transmitting connection by the engagement of the first axial toothing (4) with the second axial toothing (13), characterized by , 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, 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, into which the first teeth (5) engage. [2] Coupling device according to claim 1, characterized by, that both the first axial toothing (4) has first pockets (6) 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 by , 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 by , that the first and / or the second pockets (6, 15) are closed at both radial ends. [5] Coupling device according to any one of the preceding claims, characterized by , that the first and second teeth (5, 14) and the first and second pockets (6, 15) have a cross-sectional shape in the form of an isosceles trapezoid. [6] Coupling device according to any of the preceding claims, characterized by, that the two coupling elements (1, 10) are designed as ring discs 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] Separation unit for a mechanical system, by means of which two rotating system units can be detachably separated from each other, 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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