Air suspension compressor for a vehicle with oscillating movement of the motor shaft

Abstract

Air spring compressor (10) for a vehicle, preferably for a vehicle compressed air system (34), in particular for an air spring system of a vehicle, comprising an electric drive motor (36) mounted on a rotatable motor shaft (14), wherein a stroke axis (D) of a piston (18) of the air spring compressor (10) corresponds to a rotation axis (C) of the electric drive motor (36), wherein a wobble bearing (12) is arranged at least at an axial end (40) of the motor shaft (14), wherein a rotary movement of a rotor (22) of the electric drive motor (36) can be converted into a longitudinally axial oscillating movement of the motor shaft (14) relative to the wobble bearing (12), and the wobble bearing (12) drives the piston (18), characterized in that the wobble bearing (12) is designed as a rotating bearing which supports the rotationally fixed motor shaft (14).

Description

[0001] The present invention relates to an air spring compressor for a vehicle, preferably for a vehicle compressed air system, in particular for an air spring system of a vehicle, comprising an electric drive motor mounted on a rotatable motor shaft. The present invention further relates to a compressed air system of a vehicle and to a vehicle comprising a compressed air system. STATE OF THE ART

[0002] Various air suspension compressors for vehicles are known from the prior art, in which eccentrics and connecting rods are used so that rotational movements of drive motors can be converted into longitudinal axial movements of pistons by the eccentrics and connecting rods. To achieve this conversion, the eccentrics and connecting rods are arranged at right angles to each other. In other words, the direction of rotation of the drive motor's shaft is perpendicular to the stroke direction of the piston.

[0003] A compressor of this type for a motor vehicle air suspension system is described, for example, in EP 1 375 919 A1. The compressor comprises a cylinder, with a piston of the cylinder being attached to a drive motor via a connecting rod with a longitudinal axis oriented perpendicular to the connecting rod stroke direction. A large installation space is required to accommodate the compressor within the air suspension system.

[0004] DE 100 05 929 A1 further discloses a compressor with a piston compressor, wherein the compressor can be used in automotive air suspension systems. A piston of the piston compressor is connected via a connecting rod to a motor shaft of an electric motor, wherein one connecting rod stroke direction is perpendicular to the motor shaft. Due to a rotational movement of the electric motor and a stroke movement of the piston, strong vibrations can be generated during operation.

[0005] DE 10 2013 105 217 A1 discloses a compressor for generating a pressure medium, wherein a piston is arranged movably along an axis in a pressure chamber and a motor is associated with this piston, which causes the movement of the piston. To reduce the required housing volume, a drive shaft of the motor is arranged in the axis of the piston or parallel to it.

[0006] US patent 2005 / 0074342 A1 discloses a motorized vacuum / pressure pump with a wobble bearing piston drive mechanism for converting a rotary motion of a motor into a reciprocating motion of a piston and with a valve that is selectable for switching the pump between vacuum and pressure pumping modes.

[0007] DE 10 2012 007 291 A1 discloses a compressor for gaseous or liquid media with a compressor housing connected to an inlet line and an outlet line, and at least one piston arranged in the compressor housing, which forms a compressor chamber with the compressor housing, wherein the compressor is driven by an electric motor. It is provided that the piston is driven directly by an electric linear motor and thus set in motion by a direct-drive electric linear motor. With known compressors, the problem arises that the air spring compressors with the eccentric and connecting rod are based on a relatively large housing volume and require a large amount of installation space. Furthermore, a number of complex mechanical components and bearings are required.

[0008] US Patent 4,796,430 A1 discloses a compressor for refrigerators that can be driven by a drive motor. In this design, a rotational axis of a drive shaft of the drive motor corresponds to a stroke axis of a piston of the compressor, such that the stroke and rotational axes are parallel to each other.

[0009] DE 24 21 686 A1 also discloses a compressor with parallel stroke and rotation axes of piston and drive motor.

[0010] Furthermore, a disadvantage of the prior art is that the rotational movements of the drive motor and the piston's reciprocating movements achieved with the eccentric and connecting rod can result in a large oscillating mass. This generates strong vibrations and causes a high level of acoustic noise.

[0011] Based on the above prior art, the object of the invention is to propose an air spring compressor with low structural complexity and a compact design with low space requirements and to reduce the manufacturing costs of the air spring compressor.

[0012] Furthermore, the invention aims to improve acoustics during the operation of the air spring compressor.

[0013] This problem is solved by an air spring compressor for a vehicle with the features of claim 1, a compressed air system with the features of claim 8, and a vehicle with the features of claim 9. Advantageous further developments of the invention are the subject matter of the dependent claims. REVELATION OF THE INVENTION

[0014] The invention relates to an air spring compressor for a vehicle, preferably for a vehicle compressed air system, in particular for an air spring system of a vehicle, comprising an electric drive motor attached to a rotatable motor shaft.

[0015] According to the invention, it is proposed that a stroke axis of a piston of the air spring compressor corresponds to a rotation axis of the electric drive motor.

[0016] Thus, an air spring compressor is proposed in which the stroke shaft of a cylinder piston and the rotation shaft of the electric drive motor overlap, or rather, form a structural identity. The feature whereby the stroke axis of the piston and the rotation axis of the drive motor correspond allows for a smaller housing volume and reduced operating noise of the air spring compressor compared to a conventional air spring compressor. Furthermore, the air spring compressor can be housed in a small installation space and thus integrated into a vehicle.

[0017] It is further advantageous that no eccentrics or connecting rods are required to connect the piston to the motor shaft or the drive motor. This results in a low oscillating mass during operation of the electric drive motor. The reduction of oscillations also significantly reduces vibrations generated by these oscillations, thus dampening noise during operation and improving acoustics.

[0018] It is therefore advantageous that the piston's stroke axis is designed as a continuation of the electric drive motor's axis of rotation. This enables an extremely compact design with the same air output, allowing the air spring compressor according to the invention to be arranged in a space-constrained environment within the vehicle. This compact design allows the air spring compressor to be integrated into the vehicle's air spring system in a space-saving manner.

[0019] The air spring compressor according to the invention further advantageously achieves a reduction in size while maintaining the same air output. Furthermore, the moving mass and the number of parts to be produced for the air spring compressor according to the invention are correspondingly reduced and simplified.

[0020] According to the invention, a wobble bearing is arranged at least at one axial end of the motor shaft, wherein a rotary motion of a rotor of the electric drive motor can be converted into a longitudinally axial oscillating motion along the motor shaft, and preferably the wobble bearing drives the piston. The motor shaft can be mounted to allow rotational movement by means of the wobble bearing. The wobble bearing is designed as a single-piece element and is rotatably mounted around the motor shaft for motion and force conversion, whereby the wobble bearing can rotate at a different speed than the motor shaft. Preferably, the wobble bearing is mounted to be rotationally fixed relative to the motor shaft and longitudinally displaceable, with a mechanical coupling element converting the rotary motion of the motor shaft into an axial motion of the wobble bearing.In other words, the rotational speeds of the wobble bearing and the rotational speed of the drive motor's rotor can vary. This advantageously allows a radial movement of the rotor to be converted into an axial movement of the motor shaft, thus enabling a longitudinal axial stroke of the piston.

[0021] Furthermore, according to the invention, the wobble bearing is designed as a rotating bearing that supports the rotationally fixed motor shaft. For this purpose, the wobble bearing can serve as the rotor of the motor, and the motor shaft mounted therein can be rotationally fixed to the piston. In this embodiment, the motor shaft moves longitudinally, with the wobble bearing being axially fixed but rotatably mounted around the motor shaft. The reciprocating motion of the motor shaft serves as the drive for the piston.

[0022] It is also conceivable that a rotatable wobble bearing or a rotatable motor shaft is connected to the piston via a rotary bearing, so that a rotating element such as a wobble bearing and / or motor shaft can also perform a reciprocating movement and be used as a drive for the stationary piston.

[0023] In an alternative embodiment not part of the invention, the wobble bearing can be designed as a rotationally fixed bearing. The wobble bearing can be arranged at an axial end of the motor shaft and slidably mounted on the motor shaft by means of at least one fastening element. It is advantageous that relative rotation between the wobble bearing and the motor shaft can be prevented, so that a longitudinal axial stroke of the air spring compressor piston can be generated by the arrangement of the wobble bearing. Advantageously, the wobble bearing can be fixed in a longitudinal guide at the axial end of the motor shaft in a rotationally fixed manner.

[0024] Advantageously, the wobble bearing can be connected to the piston, and its stroke can drive the piston. Furthermore, at least one shaft bearing, in particular at least one roller bearing, can be advantageously mounted on the motor shaft to guide and support the rotating motor shaft.

[0025] In a further advantageous embodiment, at least one positive guidance system for converting rotational movements into axial movements can be designed in the wobble bearing and / or in the motor shaft. Advantageously, the positive guidance system can be designed as an endless guide or as a closed guide track for a sliding, sliding, or rolling element such as a ball, a guide nose, a rolling element, etc. This advantageously achieves the wobble bearing being oscillated longitudinally along the motor shaft during a 360° rotation of the motor shaft, and in particular, performing at least one complete oscillatory movement during a 360° rotation of the motor shaft.

[0026] Starting from the previous embodiment, at least one rolling element can be provided between the wobble bearing and the motor shaft, so that longitudinal axial movement of the wobble bearing relative to the axis of rotation of the motor shaft can be enabled by movement of the rolling element along the positive guide. Advantageously, the rolling element can be designed as a bearing ball that can run along a closed guide track designed as a positive guide. The guide track can be arranged at least partially on a surface of the end section of the motor shaft or on an inner surface of the wobble bearing, and the rolling element is arranged accordingly on the complementary part.

[0027] In a further advantageous embodiment, two wobble bearings can be arranged at the two opposite axial ends of the motor shaft, forming a two-stage, double-piston air spring compressor with a low-pressure stage and a high-pressure stage. In this embodiment, it is proposed to first compress the air in the low-pressure stage, where the air is compressed for the first time by a first piston and then enters the high-pressure stage, where it is further compressed by a second piston. Advantageously, an air outlet of the low-pressure stage can be connected to an air inlet of the high-pressure stage, wherein, prior to entering the high-pressure stage, the air can be compressed to an intermediate pressure by the first piston, and the compressed air can then be further compressed in the high-pressure stage by the second piston.It is advantageous that higher pressures can be achieved with the same air volume compared to a single-piston air spring compressor. To enable the conversion of a rotational movement of the motor shaft into a longitudinal axial stroke of the pistons without connecting rods or eccentrics, this further development incorporates two wobble bearings, which can be mounted to the two opposite axial ends of the motor shaft by means of at least one fastening element. Alternatively, a single wobble bearing can drive both pistons, in particular, drive them offset by 180°.

[0028] Based on the previous embodiment, different stroke lengths can be implemented in the low-pressure and high-pressure stages. By setting different stroke lengths for the respective pressure stages, varying nominal pressure values ​​for each cylinder in the corresponding pressure stage can be determined. It is advantageous that different pressure levels, particularly cascaded, can be generated by connecting several compression stages in series.

[0029] In a secondary aspect of the invention, a compressed air system, in particular a compressed air spring system, for a vehicle is proposed. The compressed air system comprises at least one air spring compressor, which is configured according to one of the aforementioned possible embodiments.

[0030] In a further subordinate aspect, a vehicle is proposed which includes a compressed air system according to the embodiment above. DRAWINGS

[0031] Further advantages become apparent from the accompanying drawing description. The drawings illustrate exemplary embodiments of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0032] They show: Fig. 1 in a perspective view an air spring compressor according to an embodiment not belonging to the invention; Fig. 2 in a perspective view an air spring compressor according to a further embodiment; Fig. 3 in a perspective view a wobble bearing of an air spring compressor according to a further embodiment; Fig. 4 in a perspective view a wobble bearing of an air spring compressor according to a further embodiment not belonging to the invention; Fig. 5 Front view of the in Fig. 4 depicted wobble bearings; Fig. 6a Side view of the in Fig. 4 depicted wobble bearing; and Fig. 6b a longitudinal section AA through the in Fig. 4 depicted wobble bearings.

[0033] In the figures, similar elements are numbered with the same reference symbols. The figures merely show examples and are not to be understood as limiting.

[0034] The Fig. Figure 1 shows a first embodiment of an air spring compressor 10 in which a wobble bearing 12 is arranged. A stator 24 and a rotor 22 of an electric motor 36 are arranged in a housing 32 of the air spring compressor 10, the electric motor 36 being designed as an electric drive motor 36. During operation, a motor shaft 14 rotates about an axis of rotation C in a direction of rotation A. A shaft bearing 20 is arranged to guide and support the rotating motor shaft 14, and the shaft bearing 20 can be designed as a rolling bearing. To convert rotational movements of the motor shaft 14 into longitudinal axial stroke movements of a piston 18 of a cylinder 16 along a stroke direction B, the wobble bearing 12 is fixedly arranged at an axial end 40 of the motor shaft 14, and the wobble bearing 12 can be designed as a rotationally fixed bearing and is connected to the piston 18.Thus, the stroke axis D of the piston 18 corresponds to the axis of rotation C of the motor shaft 14, with the piston 18 being driven by the oscillating movement of the rocker bearing 12 along the motor shaft 14. Because the air spring compressor 10 is equipped with the rocker bearing 12, an eccentric and a connecting rod with connecting rod bearing can be omitted, resulting in a low oscillating mass during operation of the electric motor 36 and thus contributing to low vibrations and improved acoustics. Furthermore, a positive guidance 26 is provided in the rocker bearing 12 with respect to the motor shaft 14, wherein the positive guidance 26 is a closed guide track 28 for at least one rolling element 30 (in the . Fig. (1 not shown) is designed. By having the rolling element 30 run along the positive guide 26 between the wobble bearing 12 and the motor shaft 14, longitudinal axial movement of the wobble bearing 12 relative to the axis of rotation C of the motor shaft 14 is made possible.

[0035] In the Fig. Figure 2 shows a further embodiment of an air spring compressor 10 with a wobble bearing 12. A motor shaft 14 of an electric motor 36, designed as an electric drive motor 36, can rotate about an axis of rotation C in a direction of rotation A, with a stator 24 arranged around the motor shaft 14. A shaft bearing 20 is arranged for guiding and supporting the rotating motor shaft 14, and the wobble bearing 12 is arranged for converting a rotational movement of the motor shaft 14 into a longitudinal axial movement of the wobble bearing 12. In comparison to the wobble bearing 12 in the Fig. 1 is the one in the Fig. The two provided wobble bearings 12 are rotatably mounted and serve as the motor rotor. Furthermore, the wobble bearing 12 is not located at the axial end 40 of the motor shaft 14, but rather surrounds the surface 44 of the motor shaft 14 and supports the stationary motor shaft 14. The motor shaft 14 is mounted to allow longitudinal axial movement, with the cylinder piston 18 being rigidly connected to the motor shaft. The cylinder piston 18 is moved within the rotating wobble bearing 12 by an axial oscillating movement of the motor shaft. The wobble bearing also has fastening means 42. A positive guide 26, designed as a closed guide track 28, is provided in both the rotatable wobble bearing 12 and the rotationally fixed and longitudinally axially movable motor shaft 14, with at least one rolling element 30 (in the Fig. (2 not shown) is arranged so that, during operation of the electric motor 36, the movement of the rolling element 30 along the positive guide 26 of the rotating wobble bearing 12 enables a longitudinal axial stroke movement of the motor shaft 14 and thus of the piston 18 of the cylinder 16. A stroke axis D corresponds to the axis of rotation C of the motor shaft 14.

[0036] In the Fig. Figure 3 shows a further embodiment of a wobble bearing 12, wherein the wobble bearing 12 is arranged to convert a rotary motion of a motor shaft 14 into a longitudinally axial oscillating motion of the motor shaft 14 relative to the wobble bearing 12. To achieve this, a spiral guide 26 is formed in the motor shaft 14, wherein the guide 26 can be designed as a closed guide track 28. Two rolling elements 30 can move along the guide between the wobble bearing 12 and the motor shaft 14. Furthermore, the wobble bearing 12 can be fastened to the motor shaft 14 by means of fastening means 42. It is possible to design the wobble bearing 12 as a stationary component and use it as a drive for the piston 18, or to design the motor shaft 14 as a stationary component and use it as a drive for the piston 18. Accordingly, either the motor shaft 14 is part of the rotor, or the wobble bearing 12 is.

[0037] In the Fig. 4, Fig. 5, Fig. 6a, Fig. Figure 6b shows a further embodiment of a wobble bearing 12, which can be mounted on a motor shaft 14 by means of fastening means 42. The wobble bearing 12 is arranged on the end face of the motor shaft 14, and the end face of the wobble bearing 12 can simultaneously be designed as a piston 18. Because a positive guide 26 is formed in both the motor shaft 14 and the wobble bearing 12, rolling elements 30 can run between the wobble bearing 12 and the motor shaft 14 along the positive guides 26. This allows a rotational movement of the motor shaft 14 to be converted into a longitudinally axial oscillating movement of the motor shaft 14. The positive guides 26 are designed as spiral-shaped, closed guide tracks 28. Reference symbol list 10 air spring compressor 12 wobble bearings 14 Motor shaft 16 cylinders 18 pistons 20 shaft bearings 22 runners 24 Stator 26 Coercive management 28 Guide rail 30 rolling element 32 cases 34 Vehicle compressed air system 36 Electric motor, electric drive motor 38 Twin-piston air spring compressor 40 axial end 42 Fasteners 44 surface A Direction of rotation B Lifting direction C axis of rotation D lifting axis

Claims

[1] Air spring compressor (10) for a vehicle, preferably for a vehicle compressed air system (34), in particular for an air spring system of a vehicle, comprising an electric drive motor (36) mounted on a rotatable motor shaft (14), wherein a stroke axis (D) of a piston (18) of the air spring compressor (10) corresponds to a rotation axis (C) of the electric drive motor (36), wherein a wobble bearing (12) is arranged at least at one axial end (40) of the motor shaft (14), wherein a rotary movement of a rotor (22) of the electric drive motor (36) can be converted into a longitudinally axial oscillating movement of the motor shaft (14) relative to the wobble bearing (12), and the wobble bearing (12) drives the piston (18). characterized by , that the wobble bearing (12) is designed as a rotating bearing which supports the non-rotating motor shaft (14). [2] Air spring compressor (10) according to claim 1, characterized by , that the motor shaft (14) is connected to the piston (18) [3] Air spring compressor (10) according to any of the preceding claims, characterized by , that at least one positive guidance (26) for converting rotational movements into axial movements is formed in the wobble bearing (12) and / or in the motor shaft (14). [4] Air spring compressor (10) according to claim 3, characterized by , that at least one rolling element (30) is provided between the wobble bearing (12) and the motor shaft (14), so that by moving the rolling element (30) along the positive guide (26) a longitudinal axial movement of the wobble bearing (12) relative to the axis of rotation (C) of the motor shaft (14) can be enabled. [5] Air spring compressor (10) according to any of the preceding claims, characterized by , that two wobble bearings (12) are arranged at the two opposite axial ends (40) of the motor shaft (14), so that a two-stage double-piston air spring compressor (38) with a low-pressure stage and a high-pressure stage is formed. [6] Compressed air system (34), in particular compressed air spring system, of a vehicle, comprising at least one air spring compressor (10) according to one of the preceding claims. [7] Vehicle comprising a compressed air system (34) according to claim 6.

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