Belt pulley decoupler with lubricant flow in main direction

Abstract

The invention relates to a pulley decoupler (1) for damping rotational irregularities for a motor vehicle, comprising: a pulley (2) for introducing or discharging torque, the pulley having a traction means receiving area (3) for contacting a circulating traction means in a force-transmitting manner; a flange (4) rotationally coupled to the pulley (2) for discharging or introducing torque; an elastic element (5, 6) inserted between the pulley (2) and the flange (4); a cover (7) arranged on the pulley (2), the cover and the pulley (2) forming a receiving space (8) for the elastic element (5); and a friction ring (9) abutting against the cover (7), wherein the friction ring (9) has an inner circumferential surface (10) which is inclined relative to the axial direction of the pulley decoupler (1) such that, during operation, lubricant is forced into the receiving space (8) due to centrifugal force.

Description

Technical Field

[0001] The present invention relates to a belt pulley decoupler for a motor vehicle for attenuating rotational unevenness, which comprises: a belt pulley for introducing or discharging torque, the belt pulley having a traction means receiving area for contacting a circulating traction means such as a belt in a force-transmitting manner; a (driven) flange for discharging or introducing torque, which is rotationally coupled to the belt pulley and is preferably arranged coaxially with the belt pulley and is preferably supported rotatably within a limited angular range relative to the belt pulley; at least one elastic element inserted between the belt pulley and the flange, the elastic element preferably connecting the belt pulley and the flange in a torque-transmitting and vibration-damping manner; a cover arranged on the belt pulley, the cover and the belt pulley forming a receiving space for the elastic element, in which a lubricant is present; and a friction ring, which abuts against the cover. Background Art

[0002] Belt pulley decouplers are already known from the prior art. For example, DE 10 20213 206 444 A1 discloses a drive wheel having a drive disc with a traction mechanism engagement region and a shaft engagement region, which is rotatable relative to the traction mechanism engagement region against the damping effect of at least one torsional vibration damping device, wherein the torsional vibration damping device is combined with a sealing and positioning device, which serves to orient the drive disc in the axial direction. The sealing and positioning device is formed by a disc spring and a friction ring preloaded by the disc spring and covers a spring receiving space filled with lubricant.

[0003] Other documents WO 2012 / 075984A1 also disclose a pulley damper for damping torsional vibrations of a drive shaft, comprising: a pulley for driving a traction mechanism, in particular a traction belt; an input flange that can be connected to the drive shaft in a rotationally fixed manner, wherein the input flange has at least one fixing mechanism, in particular an opening, for connecting the input flange to the drive shaft; a torsional vibration damper, in particular a decoupler for torsional vibrations, for transmitting torsional vibrations introduced via the input flange to the pulley and a bearing formed between the pulley and the input flange for supporting the pulley on the input flange, wherein the bearing is arranged in a radial direction between the fixing mechanism and the rotation axis of the input flange.

[0004] However, the prior art always has the disadvantage that lubricants are required in the pulley decoupler due to wear and noise. During operation, the lubricant is centrifuged toward the surroundings due to the centrifugal force in the interior of the pulley decoupler, i.e. in the receiving space for the elastic element, when the pulley decoupler rotates. However, during start-stop operation, the lubricant reaches the radial inner region of the pulley decoupler, i.e. in the region of the friction ring and the hub, where a flange is usually arranged. Since the friction ring usually protrudes into the interior in the axial direction, an undercut is formed in the radial direction, in which the lubricant can accumulate. As the speed increases, the lubricant (accumulated in the undercut) is pressed outward in an undirected manner, which can lead to a shortage of lubricant in the (spring) receiving space, or even to an overflow of the lubricant from the interior of the pulley decoupler, which is also called the spring channel. Summary of the invention

[0005] The object of the present invention is therefore to avoid or at least reduce the disadvantages of the prior art. In particular, a belt pulley decoupler is to be provided in which it is prevented that lubricant escapes, in particular in the region of the friction ring, or accumulates there.

[0006] This object is achieved according to the invention in such a device in that the friction ring has an inner circumferential surface which is inclined relative to the axial direction of the pulley decoupler in such a way that during operation the lubricant is forced into the receiving space due to centrifugal force. This means that the inner circumferential surface has an inclined surface, by which the main direction of the lubricant is generated at the speed towards the interior of the pulley decoupler, i.e. the receiving space. The inclined surface can be designed linearly or nonlinearly.

[0007] This has the advantage that, at increasing speeds, the lubricant is pressed radially outward and forced radially inwards due to the inclination / configuration of the inner circumferential surface. In other words, by configuring the friction ring, a main direction (axially inwards) is created for the lubricant flow, especially at speeds.

[0008] Advantageous embodiments are claimed in the dependent claims and are explained in detail below.

[0009] According to a preferred embodiment, the friction ring can have an inner diameter, which increases in the direction of the receiving space. That is to say, the inner diameter increases in the radial direction as the axial extension extends. The inner diameter thus increases from the axial outside to the axial inside (in the radial direction). In other words, the inner diameter at the axial outside of the friction ring, i.e. on the side facing away from the receiving space or facing away from the belt pulley, is smaller than the inner diameter at the axial inside, i.e. on the side facing toward the receiving space or facing the belt pulley. Therefore, when the lubricant is pressed radially outward (due to centrifugal force), it is guided in the axial direction into the interior of the belt pulley decoupler. This prevents the lubricant from centrifuging out of the belt pulley decoupler.

[0010] In an advantageous refinement, the inner circumference can correspond to the outer side of a truncated cone, wherein the angle between the cone axis of the truncated cone and the generatrix is ​​less than 10°. This ensures that the difference between the inner diameter on the axial outside and the inner diameter on the axial inside does not become too large, so that the radial extension of the section forming the inner circumferential surface can be designed to be small.

[0011] It is particularly preferred that the angle is between 2° and 5°, more preferably between 3° and 4°. These angle values ​​have proven to be particularly suitable and are at the same time simple to produce.

[0012] Furthermore, it is preferred that the outer diameter of the outer circumferential surface forming the section of the inner circumferential surface is constant. As a result, the friction ring can be easily mounted on the straight inner circumferential surface of the cover.

[0013] According to another preferred embodiment, the inner circumferential surface can have a curvature. Thus, the lubricant can be guided into the interior of the pulley decoupler even at low rotation speeds, if necessary. According to an advantageous improvement of this embodiment, the inner circumferential surface can be curved elliptically, hyperbolically or parabolically.

[0014] In a preferred embodiment, the friction ring can have a tubular section extending in the axial direction, wherein the thickness, ie the radial extension, of the tubular section decreases in the direction of the receiving space. Thus, the main direction can be realized in a simple manner.

[0015] According to a preferred embodiment, the belt pulley decoupler can have a disk spring which is arranged in such a way that it exerts an axial preload on the friction ring in the direction of the cover. As a result, a permanent friction torque / damping torque is exerted by the friction ring on the cover, which advantageously has a vibration-damping effect. Preferably, the friction ring is arranged in the axial direction between the cover and the disk spring.

[0016] It is also preferred that the friction ring abuts against the radial inner side and / or axial outer side of the cover. Therefore, a simple positioning of the friction ring relative to the cover can be ensured, and at the same time a large friction surface between the cover and the friction ring can be provided.

[0017] In an advantageous embodiment, the cover, the friction ring and / or the disc spring can limit the receiving space in the axial direction, thereby ensuring that lubricant cannot escape from the receiving space. In another axial direction, the receiving space can preferably be limited by the belt pulley, in particular completely surrounded.

[0018] According to a preferred embodiment, the pulley decoupler can have a torsional vibration damper, which is arranged to be fixed to the flange or to the pulley. Thus, torsional vibrations can be additionally damped, which has a favorable effect on the acoustic properties.

[0019] In other words, the invention relates to a grease-filled pulley decoupler (RSE). The problem in pulley decoupling systems is that lubricant is required due to wear and noise, which (at speed, i.e. during operation) is centrifuged in the interior of the decoupling element / pulley decoupler due to centrifugal forces and reaches the region of a friction ring (or multiple friction rings) and / or a hub during start-stop operation. As the speed increases, the lubricant is pressed outwards in an undirected manner, which can lead to a lack of lubricant in the interior / in the spring channel and to lubricant overflow. According to the invention, a pulley decoupler with a friction ring is proposed, which has an inclined surface, so that at the speed the main direction of the lubricant is generated in the direction of the interior of the pulley decoupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention is explained below with the aid of the accompanying drawings. The accompanying drawings show:

[0021] Figure 1 The longitudinal section through a pulley decoupler according to the invention is shown, which has a friction ring which creates a main direction for the lubricant.

[0022] The drawings are only schematic and serve only for understanding the invention. Identical elements are provided with the same reference numerals. DETAILED DESCRIPTION

[0023] Figure 1 A pulley decoupler 1 for a motor vehicle for damping rotational irregularities is shown according to the invention. With the pulley decoupler 1, an auxiliary unit of an internal combustion engine can be driven, for example, with the aid of a circulating traction mechanism such as a V-belt or a toothed belt. Such an auxiliary unit is, for example, a generator or an air conditioning compressor.

[0024] The belt pulley decoupler 1 has a belt pulley 2 for introducing or dissipating torque. The belt pulley 2 has a traction means receiving region 3 for contacting a circulating traction means in a force-transmitting manner. In the exemplary embodiment shown, the traction means receiving region 3 is toothed.

[0025] The belt pulley decoupler 1 has a flange 4 for discharging or introducing torque. The flange 4 is rotationally coupled to the belt pulley 2. The flange 4 is arranged coaxially with the belt pulley 2. The flange 4 and the belt pulley 2 are supported so that they can rotate relative to each other within a limited angular range.

[0026] The pulley decoupler 1 has a spring element 5. The spring element 5 serves as a spring device between the pulley 2 and the flange 4. The spring element 5 is inserted into the torque flow between the pulley 2 and the flange 4. The spring element 5 thus connects the flange 4 to the pulley 2 in a torque-transmitting and vibration-damping manner. In the illustrated embodiment, the spring element is designed as an arc spring 6.

[0027] The pulley decoupler 1 has a cover 7. The cover 7 is fixedly mounted on the pulley 2. The cover 7 and the pulley 2 form a receiving space 8. The receiving space 8 is formed axially between the cover 7 and the pulley 2. The receiving space 8 can also be referred to as the inner space or spring channel of the pulley decoupler 1 below. The spring element 5 is arranged in the receiving space 8. Lubricant is contained in the receiving space 8. The elastic element 5 is thus lubricated. The lubricant accumulated in the radially outer region of the receiving space 8, i.e., in the interior of the pulley decoupler 1, at a rotational speed is Figure 1 The shading is indicated by interrupted lines which are parallel to one another.

[0028] The pulley decoupler 1 has a friction ring 9. The friction ring 9 lies on the cover 7. The friction ring 9 is pressed against the cover 7 so that it exerts a (permanent) friction torque / damping torque on the cover 7. Vibrations are damped by the friction ring 9 because the kinetic energy of the friction disk decoupler 1 is converted into heat energy. The friction ring 9 rests on the axial outside of the cover 7, i.e. on the axial side facing away from the friction disk. The friction ring 9 rests on the (radial) inner circumferential surface of the cover 7.

[0029] The friction ring 9 has a (radial) inner circumferential surface 10, which is inclined relative to the axial direction of the pulley decoupler 1. The inner circumferential surface 10 is inclined so that during operation of the friction disk decoupler 1, the lubricant is forcibly conducted / guided into the receiving space 8 due to centrifugal force. The axial direction is the direction along the longitudinal axis L of the pulley decoupler 1. The inner circumferential surface 10 is therefore inclined relative to the axial direction so that the diameter of the inner circumferential surface 10 increases in the direction of the pulley 2, i.e., in the direction of the interior of the pulley decoupler 1. That is to say, the inner diameter of the friction ring 9 increases in the direction of the interior / interior of the pulley decoupler 1. The friction ring 9 has a disk-shaped section extending in the radial direction and a tubular section extending in the axial direction, i.e., a section with a circular cross section. The thickness of the tubular section decreases in the direction of the interior of the pulley decoupler 1.

[0030] In the embodiment shown, the inner diameter of the friction ring 9 increases continuously. The inner circumferential surface 10 has the shape of the outer side surface of a truncated cone. In other words, the inner circumferential surface 10 is continuously formed. The angle enclosed between the cone axis and the generatrix of the truncated cone is less than 10°. The angle is constant. In other words, the inner circumferential surface 10 is inclined at the angle relative to the axial direction in the longitudinal section. In the embodiment shown, the angle is less than 10°. Preferably, the angle is less than 5°, for example, between 2° and 5°. It is also preferred that the angle is between 3° and 4°.

[0031] In an alternative embodiment, the inner diameter of the friction ring 9 can also be discontinuously increased. For example, the inner circumferential surface 10 can have a curvature. The inner circumferential surface 10 can be curved elliptically, i.e. with a positive curvature, hyperbolically, i.e. with a negative curvature, or parabolically, i.e. with a constant curvature. Thus, the inner circumferential surface 10 can be curved convexly or concavely.

[0032] The belt pulley decoupler 1 has a disc spring 11. The disc spring 11 is arranged so that it applies axial preload to the friction ring 9. The disc spring 11 abuts against the axial outside of the friction ring 9, that is, against the axial side facing away from the cover. The friction ring 9 is pressed against the cover 7 by the spring force of the disc spring 11. Therefore, the friction ring 9 is arranged between the cover 7 and the disc spring 11 in the axial direction. The accommodating space 8 is covered by the disc spring 11. The friction ring 9 serves as a seal between the cover 7 and the disc spring 11 and prevents lubricant from escaping.

[0033] The belt pulley 2 is rotatably supported on a hub 13 of the belt pulley decoupler 1 via a bearing 12. The hub 13 is connected to the crankshaft of the internal combustion engine in a rotationally fixed manner. The flange 4 is mounted to the hub 13 in a rotationally fixed manner. The hub 13 has a radially outwardly protruding, preferably circumferential edge 14, on which the belt pulley 2 is supported in the axial direction. A second friction ring 15 is arranged between the edge 14 and the belt pulley 2, which applies a friction torque / damping torque to the belt pulley.

[0034] A torsional vibration damper 16 is mounted on the pulley decoupler 1. The torsional vibration damper 16 is fixedly connected to the flange 4 (and the hub 13). The fixing mechanism 17 fixes the hub 13, the flange 4, the disc spring 11, the torsional vibration damper 16 and the disc 18 to each other.

[0035] Description of Reference Numerals

[0036] 1 Belt pulley decoupler 2 Belt pulley 3 Traction means receiving area 4 Flange 5 Elastic element 6 Curved spring 7 Cover 8 Receiving space 9 Friction ring 10 Inner circumferential surface 11 Disc spring 12 Bearing 13 Hub 14 Edge 15 Second friction ring 16 Torsional vibration damper 17 Fastening means 18 Longitudinal axis of disk L.

Claims

1. A belt pulley decoupler (1) for damping rotational unevenness for a motor vehicle, comprising: a belt pulley (2) for introducing or discharging torque, the belt pulley having a traction mechanism receiving area (3) for contacting a circulating traction mechanism in a force-transmitting manner; a flange (4) rotationally coupled to the belt pulley (2) for discharging or introducing torque; an elastic element (5, 6) inserted between the belt pulley (2) and the flange (4); a cover (7) arranged on the belt pulley (2), the cover and the belt pulley (2) forming a receiving space (8) for the elastic element (5), in which a lubricant is present; and a friction ring (9) which abuts against the cover (7) and has a tubular section extending in the axial direction. It is characterized in that The tubular section of the friction ring (9) has an inner circumferential surface (10), the inner diameter of which increases in the direction of the accommodating space (8), whereby the inner circumferential surface is inclined relative to the axial direction of the belt pulley decoupler (1) so that during operation, the lubricant is forced into the accommodating space (8) through the channel between the tubular section and the flange (4) due to centrifugal force.

2. The belt pulley decoupler (1) according to claim 1, It is characterized in that The inner circumferential surface (10) corresponds to the outer side surface of a truncated cone, wherein the angle between the cone axis and the generatrix of the truncated cone is less than 10°.

3. The belt pulley decoupler (1) according to claim 2, It is characterized in that The angle is between 2° and 5°.

4. The belt pulley decoupler (1) according to claim 1, It is characterized in that The inner circumferential surface (10) has a curved portion.

5. The belt pulley decoupler (1) according to claim 4, It is characterized in that The inner circumferential surface (10) is curved elliptically, hyperbolically or parabolically.

6. The belt pulley decoupler (1) according to any one of claims 1 to 5, It is characterized in that The thickness of the tubular section gradually decreases towards the accommodating space (8).

7. The belt pulley decoupler (1) according to any one of claims 1 to 5, It is characterized in that The pulley decoupler (1) has a disc spring (11) which is designed in such a way that it exerts an axial preload on the friction ring (9) in the direction of the cover (7).

8. The belt pulley decoupler (1) according to claim 7, It is characterized in that The cover (7), the friction ring (9) and / or the disc spring (11) limit the receiving space (8) in the axial direction.

9. The belt pulley decoupler (1) according to claim 8, It is characterized in that The pulley decoupler (1) has a torsional vibration damper (16) which is arranged to be fixed to a flange or to a pulley.

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