ACTUATOR DRIVE FOR A VEHICLE

Description

[0001] The invention relates to an auxiliary drive for a drive engine and to a motor vehicle with such an auxiliary drive.

[0002] It is known in practice to drive auxiliary units via an auxiliary unit drive. For example, auxiliary units or power consumers in general, such as pumps or generators for generating electricity, are driven via a belt. The belt is driven by a drive pulley or driving pulley, which, in vehicles with internal combustion engines, is non-rotatably attached to one end of the engine's crankshaft or can be driven indirectly by a crankshaft. Document DE 10 2017 203295 A1 describes a corresponding auxiliary unit drive.

[0003] The belt and its physical properties, such as the belt width, are designed to ensure that all auxiliary components can be supplied with sufficient power. This is based on the auxiliary component or power consumer that bears the greatest load. For all other auxiliary components, however, this belt design is just right at best, or significantly oversized if they have to bear significantly lower loads.

[0004] It is therefore an object of the invention to provide an improved accessory drive with which disadvantages of conventional accessory drives can be avoided.

[0005] This object is achieved by an auxiliary drive having the features of independent claim 1. Advantageous further developments are specified in the dependent claims and the description.

[0006] According to a first general aspect of the invention, an accessory drive for a drive engine and / or a vehicle is provided. The accessory drive is a device for driving the accessories of a motor vehicle. In one embodiment, the accessory drive can be the accessory drive of an internal combustion engine for a motor vehicle. According to the invention, the accessory drive comprises a plurality of accessories, which can also be referred to as power consumers.

[0007] The accessory drive further comprises a first belt arranged in a first belt plane and in drive connection with the plurality of accessories.

[0008] The accessory drive further comprises a second belt arranged in a second belt plane that is offset parallel to the first belt plane and is driveably connected to only a portion of the plurality of accessory units, preferably to increase the torque transmitted to that portion of the plurality of accessory units. The accessory drive further comprises a drive shaft that is driveably connected to the first and second belts via two drive belt tracks arranged in a rotationally fixed manner relative to one another.

[0009] In order to increase the transferable power within a belt drive with several power consumers (auxiliary units) only partially for a specific power consumer or part of the power consumers, an additional (second) belt is tensioned between the power drive and this one consumer or this part of the power consumers, so that this one power consumer or this part of the power consumers is driven by both the first belt and the second belt.

[0010] This offers the advantage that the drive power of a portion of the multiple auxiliary units can be increased without having to increase the potentially transmittable power for all of them, even though they do not absorb more load than originally intended. This allows more power to be specifically implemented for a portion of the auxiliary units, particularly by increasing the transmitted torque, while the bearing and belt loads for the other auxiliary units (power consumers) within the overall belt drive remain unchanged.

[0011] This approach is particularly advantageous when an additional auxiliary unit needs to be integrated into an existing belt drive that has a higher power requirement than the existing ones, i.e., one that requires a higher torque transmission. The same applies when an existing auxiliary unit or part of the auxiliary units in an existing belt drive needs to be replaced with units with higher power requirements.

[0012] A further advantage is that the use of two belts increases the service life of the first belt, which can also be referred to as the main belt drive. The second belt advantageously absorbs vibrations, thus extending the service life of the first belt.

[0013] A belt plane is the spatial area in which the respective belt runs or in which the respective belt moves. The belt plane can also be referred to as the drive plane. Since the second belt plane is offset parallel to the first belt plane, this means that the first belt cannot wrap around the second belt in a partial area, or that the second belt cannot wrap around the first belt in a partial area. Instead, the second belt is offset from the first belt in a direction perpendicular to the parallel belt planes.

[0014] In one embodiment, only one of the multiple auxiliary units can be driveably connected to the second belt. In other words, the transmittable power within the belt drive with multiple power consumers is partially increased only for a specific power consumer (for an auxiliary unit) by having the additional belt (second belt) stretched between the power drive and this one power consumer, so that this one power consumer is driven by both the first belt and the second belt. This offers the advantage that in the event of a significant increase in power consumption, only one of the auxiliary units has part of the required power transmitted via a second belt, which exceeds the power provided by the first belt.

[0015] In a further variant of this embodiment, the second belt can wrap around only one driving pulley and one driven pulley. Accordingly, the second belt can be designed to be particularly compact. Furthermore, this makes it particularly easy to expand an existing accessory drive with a second belt, allowing all other pulleys, idler pulleys, tension pulleys, etc., to remain unchanged.

[0016] A "driving pulley" is understood in particular to mean a pulley or belt pulley through which the torque is introduced into the accessory drive, preferably the belt. A "driven pulley" is understood in particular to mean a pulley or belt pulley that is driven by the belt from the driving pulley or driving pulley. "Wrapping" is understood in particular to mean a direct contact with an outer contour, preferably an outer contour of a pulley or belt pulley.

[0017] The auxiliary unit connected to the second belt can be an electric machine capable of operating as a generator. For example, the demands on vehicle power supplies have been steadily increasing in recent years, requiring generators to meet ever-increasing power requirements to power the growing number of electronic components. With the approach of the invention, a generator in a conventional auxiliary unit drive can be replaced with a more powerful generator with minimal effort and driven to a power-appropriate level.

[0018] In a further embodiment, the second belt can be designed as a self-tensioning belt.

[0019] A self-tensioning belt is defined as one that, for the belt tension required for torque transmission, does not require an additional element to further stretch and / or tighten the belt to create or maintain the desired belt tension. Instead, the self-tensioning belt, due to its material properties, is already tensioned upon installation to such an extent that it maintains the tension created during installation. Self-tensioning belts are also known as "elasto-belts" or "stretchy-belts" and are commercially available.

[0020] The self-tensioning belt offers the advantage that radial center distances between the driving shaft and the part of the several auxiliary units can be very short because no additional rolling element, such as is used as a tensioning device in non-self-tensioning belts, has to be in contact with the self-tensioning belt.

[0021] Accordingly, the second belt cannot partially wrap around a tension pulley and / or there cannot be a belt tensioner provided to tension the second belt. This offers the advantage of increasing the efficiency of the accessory drive through fewer rolling contacts and therefore less friction. This also offers the advantage of saving additional installation space, reducing weight, and eliminating the need for maintenance-intensive mechanics for the second belt. A belt tensioner serves the purpose of tensioning a belt. A tension pulley is a roller that uses a tensioning device to induce a defined stretch in a belt. This means that the belt is always subjected to the same tension and can therefore transmit the same forces, even though a belt stretches over time.

[0022] In a further embodiment, the accessory drive can further comprise a driving pulley that is rotatably connected and / or rotatably connected to the drive shaft. The drive pulley is designed as a double pulley, comprising a first driving belt track on which the first belt engages, and a second driving belt track on which a second belt engages. A double pulley is understood to be a pulley on which two belt tracks are radially mounted, each of which can engage a belt.

[0023] A double pulley enables a particularly compact arrangement of two belts running in parallel, offset belt planes. The driving belt tracks can be designed to have a surface adapted to the respective belt used for each track, ensuring optimal power transmission for that belt. Furthermore, the belt tracks can be configured to prevent axial "wandering" of the belts during operation, so that the first and second belts cannot overlap or rub against each other at their edges.

[0024] In an alternative embodiment, the accessory drive can further comprise a first driving pulley that is rotatably connectable to the drive shaft, is arranged in the first belt plane, and has a first driving belt track on which the first belt engages. Additionally, the accessory drive can comprise a second driving pulley that is rotatably connectable to the drive shaft, is arranged in the second belt plane and is coaxial and non-rotatably connected to the first driving pulley, and has a second driving belt track on which the second belt engages. Thus, instead of a double pulley, two axially spaced-apart conventional pulleys are used.

[0025] This offers the advantage that individual pulleys are less complex to produce. It also offers the possibility of easily adding additional pulleys if more than two belts are required.

[0026] In a further embodiment, the diameter of the two driving belt tracks arranged in a rotationally fixed manner to one another can be the same. The diameter is specified in such a way that the belts of the two belt tracks effectively have the same running speed. This is advantageous because, for example, V-belts can have different radial dimensions than flat belts. This also results in different force application points between the pulley and the belt. For example, with V-belts, power is not transmitted directly at the belt track base. The belt track base is the surface of a belt track that is radially closest to a center of rotation and is usually flat. Rather, with a V-belt, power is transmitted at the belt flanks, which run slightly raised from the belt track base.However, a flat belt would rest on the belt track base and therefore experience a slower running speed than a V-belt if the belt track base were decisive for a diameter.

[0027] Furthermore, an equal diameter and thus an equal running speed of the two belts is advantageous in order to prevent continuous slippage between the driving pulley and the driven pulley on which two belts engage.

[0028] In a further embodiment, the part of the plurality of auxiliary units that is drive-connected to the second belt can each be drive-connected to the first and second belts via two driven belt tracks arranged in a rotationally fixed manner relative to one another. Two embodiments are conceivable here. In a first embodiment, the two driven belt tracks arranged in a rotationally fixed manner relative to one another can be provided by a driven double pulley, and in a second embodiment, they can be provided by two coaxially arranged driven pulleys.

[0029] In a further embodiment, the diameter of the two driven belt tracks arranged in a rotationally fixed manner can be the same. This offers the advantage that there are no differences in rotational speed or slippage between the two engaging belts, thus preventing power loss due to friction and thus waste heat. Furthermore, an auxiliary unit that is drive-connected to both the first and second belts can be driven by both the first and second belts at the same speed.

[0030] In a further embodiment, the second belt can be designed as a V-ribbed belt. The advantage of a V-ribbed belt is that it represents a further development of the V-belt and combines the advantages of a flat belt (small radii) with those of a V-belt (smaller wrap angle required for consistent power transfer and greater friction at a constant wrap angle). The V-ribbed belt has ribs that run longitudinally. The wrap angle indicates the contact area in degrees at which one flexible component surrounds another.

[0031] The invention further comprises the following aspects: The accessory drive can be supplied by the internal combustion engine with the necessary power to drive the accessory units. In a preferred embodiment, the internal combustion engine is a reciprocating piston internal combustion engine. The vehicle can be a commercial vehicle, for example, a truck. The internal combustion engine can also be referred to below as an engine. The accessory units driven by the accessory drive can comprise an electrical machine operable as a generator, e.g., an alternator, a lubricant pump, a hydraulic pump (for example, for power steering), a cooling water pump, a fuel pump, an injection pump, a metering pump, a fan for the radiator, a compressor for an air conditioning system, an air brake or for supercharging the engine, a turbocharger, or a brake booster.

[0032] A "belt" is understood to mean, in particular, an endless belt made of an elastic material, such as fabric, leather, plastic, mixtures of plastic and carbon or carbon fiber, plastic with embedded metal reinforcements, or all common belt designs, intended for transmitting rotary motion. The belt is preferably designed without joints. The belt preferably has surface properties suitable for high torque transmission before the belt slips on a surface because the transmittable (friction) power has been exceeded. The first belt can be designed as a V-ribbed belt, flat belt, double V-belt, composite V-belt, and all other known and common belt types.The second belt may comprise any belt type that the first belt may comprise, wherein the first belt and the second belt may be of the same or different belt type.

[0033] The drive shaft can be driven directly or indirectly by a crankshaft, or it can be an extension of a crankshaft. The drive shaft can be designed as a shaft journal and / or have a shaft hub.

[0034] The invention further relates to a motor vehicle comprising an accessory drive according to the disclosures in this document. Particularly preferably, the motor vehicle is a commercial vehicle. In this case, the motor vehicle can be, in other words, a motor vehicle whose design and equipment are designed for transporting people, transporting goods, or towing trailers. For example, the motor vehicle can be a truck, a bus, and / or a semitrailer truck that is at least partially electrically powered.

[0035] The above-described preferred embodiments and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying figures. They show: Figure 1 shows an accessory drive in perspective view; Figure 2 shows an accessory drive in plan view; Figure 3 shows an accessory drive in side view.

[0036] Figure 1 shows a perspective view of an accessory drive 1, as it may be implemented by way of example. The illustrated accessory drive 1 is driven by an internal combustion engine (not shown) and comprises, for example, three accessory units 2, 2a, 2b, a first belt 3, and a second belt 4. The belts 3, 4 are driven by a driving pulley 6.

[0037] Furthermore, in this exemplary embodiment, the second belt 4 is only drive-connected to one of the three auxiliary units 2. This increases the transmittable torque that can be transmitted to this one auxiliary unit 2a by the power provided solely by the second belt. In other words, the power that the auxiliary unit 2a can absorb is thus increased.

[0038] The first belt 3 is arranged in a first belt plane 15 and is in drive connection with the plurality of auxiliary units 2, 2a, 2b. The second belt 4 is arranged in a second belt plane 16, which is offset parallel to the first belt plane 15. This is even clearer in Figure 3 to see.

[0039] Furthermore, the accessory drive 1 comprises a drive shaft 5, which is in drive connection with the first and the second belt 3, 4 via two driving belt tracks 7, 8 arranged in a rotationally fixed manner relative to one another.

[0040] The auxiliary units 2, 2b, which are driven only by the first belt 3 but not by the second belt 4, are supplied with power via the two deflection pulleys 9 and the belt tensioner 10 with a belt track to which the first belt 3 engages.

[0041] The driving belt tracks 7, 8 are arranged on a circumference of the driving belt pulley 6. In this exemplary embodiment, the driving belt pulley 6 is designed as a double belt pulley. In this example, the driving belt pulley 6, also referred to as the driving pulley 6, consists of a single component rather than two assembled components that are connected to each other in a rotationally fixed and coaxial manner.

[0042] As shown, the second belt 4 wraps only around the driving belt pulley 6 and the driven belt pulley 11, which is rotatably mounted on the auxiliary unit 2a.

[0043] The first belt 3 wraps around the driven pulleys 12 of the auxiliary unit 2, the driven pulley 2b, and the driven pulley 11 of the auxiliary unit 2a. Additionally, the first belt 3 wraps around two deflection pulleys 9 and a tension pulley 10. The deflection pulleys 9 increase the wrap angle of the belt 3 with the driving pulley 6 and a driven pulley 12. The tension pulley 10 increases both the wrap angle of a driven pulley 12. Furthermore, the belt tension of the first belt 3 is kept constant by a suitable tensioning device of the tension pulley 10. The larger the wrap angle, the greater the transmittable power.

[0044] The second belt 4 is designed as a self-tensioning belt. This allows for a very small radial center distance between the drive shaft 5 and the driven pulley 11, because no tension pulley 10 or, in general, a belt tensioner 10 is required, as is the case with the first belt 3, thus saving installation space.

[0045] As already described, the driving pulley 6 in this exemplary embodiment is designed as a double pulley. The double pulley comprises a first driving belt track 7, on which the first belt 3 engages and is guided, and a second belt track 8, on which the second belt 4 engages and is guided. The belt tracks 7, 8 are axially spaced from one another, so that the belts 3, 4 also run axially in parallel belt planes 15, 16. Alternatively, the double pulley could be designed as two individual pulleys, each having a belt track and being coaxially mounted on the driving shaft 5 in a rotationally fixed manner (not shown here).

[0046] The diameter of the two driving belt tracks, at which the force is introduced onto the belts 3, 4, is the same size, so that this also results in the same running speed of the belts 3, 4.

[0047] The two belts 3, 4 drive the auxiliary unit 2a via the driven pulley 11 with two driven belt tracks 13, 14. In this embodiment, the driven pulley 11 is designed as a double pulley. A design with two coaxially arranged driven pulleys is also possible (not shown).

[0048] The diameter of the two driven belt tracks 13, 14 is, as with the driving belt tracks 7, 8, the same, based on a force introduction from belt to a pulley, so that a nearly slip-free power transmission via the two belts 3, 4 from the driving pulley 6 to the driven pulley 11 is possible.

[0049] In other words, with this design, the driven pulley 11 is driven at the same speed by the first and second belts 3, 4.

[0050] In this embodiment, the two belts 3, 4 are designed as V-ribbed belts.

[0051] Figure 2 shows the accessory drive 1 from Figure 1 in plan view. The driving shaft 5, as in Figure 1 , is only partially visible: here, only one end of the driving shaft is shown, which is attached to the center of the driving pulley 6. The extension of the driving shaft 5, not shown, can be a crankshaft or a gear that connects the driving shaft to a crankshaft in a power-transmitting manner.

[0052] Figure 3 shows the accessory drive 1 in side view. The first belt 3 and the second belt 4 are clearly visible, arranged side by side, and the belt planes 15 and 16 for the two belts 3, 4 are shown. The belts 3, 4 do not overlap at any point.

[0053] In summary, the second belt 4 enables the transmittable power or the transmittable torque within a belt drive with multiple power consumers to be increased only partially for a specific power consumer, here the auxiliary unit 2a, since this one power consumer 2a is driven by both the first belt 3 and the additional belt drive 4. This ensures that the belt drive is not oversized and inefficient with respect to all other auxiliary units, here only the auxiliary unit 2. Thus, the bearing and belt loads for all power consumers within the overall belt drive remain unchanged, but more power can be converted via the one power consumer 2a. To illustrate the inventive approach, only one example with three auxiliary units is described here; however, the auxiliary unit drive can obviously have more than three auxiliary units.

[0054] Although the invention has been described with reference to specific embodiments, it will be apparent to one skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. Accordingly, the invention is not intended to be limited to the disclosed embodiments, but is intended to include all embodiments falling within the scope of the appended claims. List of reference symbols

[0055] 1Auxiliary unit drive 2, 2a, 2bAuxiliary unit 3First belt 4Second belt 5Driving shaft 6Driving belt wheel or pulley 7First driving belt track 8Second driving belt track 9Deflection pulley 10Idler pulley, belt tensioner 11Driven belt wheel with two belt tracks 12Driven belt wheel with one belt track 13First driven belt track 14Second driven belt track 15First belt level 16Second belt level

Claims

1. Auxiliary unit drive (1) for a drive engine, comprising a) multiple auxiliary units (2, 2a, 2b); b) a first belt (3), which is arranged in a first belt plane (15) and is in driving connection with the plurality of auxiliary units (2, 2a, 2b) c) a second belt (4) arranged in a second belt plane (16), the second belt plane being offset parallel to said first belt plane (15) and being in driving connection with only a part (2a) of said plurality of auxiliary units (2, 2a, 2b), preferably for increasing the torque transmitted to said part (2a) of said plurality of auxiliary units (2, 2a, 2b); and d) a driving shaft (5) which is in driving connection with the first and the second belt (3, 4) via two driving belt tracks (7, 8) which are arranged in a rotationally fixed manner relative to one another.

2. The auxiliary unit drive (1) of claim 1, wherein only one (2a) of the plurality of auxiliary units (2, 2a, 2b) is in driving connection with the second belt (4).

3. The auxiliary unit drive (1) of claim 2, wherein the second belt (4) loops around only a driving belt wheel (6) and a driven belt wheel (11).

4. The auxiliary unit drive (1) according to one of the preceding claims, wherein a) the second belt (4) is configured as a self-tensioning belt; and / or b) the second belt (4) does not partially wrap around a tensioning pulley (9), and / or c) at the second belt (4), no belt tensioner (9), preferably no belt tensioner (9) for tensioning the second belt (4), is provided.

5. The auxiliary unit drive (1) according to one of the preceding claims, further comprising a driving pulley (6) rotatably connectable to the driving shaft (5), which is configured as a double pulley, comprising a first driving belt track (7) on which the first belt (3) engages, and a second driving belt track (8) on which a second belt (4) engages.

6. The auxiliary unit drive (1) according to claim 1 to 4, further comprising a) a driving first belt pulley, which is arranged in the first belt plane, having a first driving belt track (7), on which the first belt (3) engages, and which is rotatably connectable to the driving shaft (5), and b) a driving second belt pulley, which is arranged in the second belt plane, the second belt pulley being arranged coaxially and rotationally fixedly to the driving first belt pulley, the second belt pulley is rotatably connectable to the driving shaft (5) and is comprising a second driving belt track (8) on which the second belt (4) engages.

7. The auxiliary unit drive according to any one of the preceding claims, wherein a diameter of the two driving belt tracks (7, 8) which are arranged in a rotationally fixed manner relative to one another is the same.

8. The auxiliary unit drive (1) according to any one of the preceding claims, wherein the part (2a) of the plurality of auxiliary units (2, 2a, 2b) which is in driving connection with the second belt (4) is in driving connection with the first and the second belt (3, 4) in each case via two driven belt tracks (13, 14) arranged in a rotationally fixed manner relative to one another.

9. The auxiliary unit drive (1) according to claim 5, wherein the two driven belt tracks (13, 14) arranged in a rotationally fixed manner relative to one another are provided by a driven double pulley (11) or by two coaxially arranged driven pulleys.

10. The auxiliary unit drive (1) according to claim 8 or 9, wherein a diameter of the two driven belt tracks (13, 14) arranged in a rotationally fixed manner relative to one another is the same.

11. The auxiliary unit drive (1) according to any one of the preceding claims, wherein an auxiliary unit (2a) in driving connection with both the first and second belts (3, 4) is driven by the first belt (3) and the second belt (4) at the same rotational speed.

12. Auxiliary unit drive (1) according to one of the preceding claims, wherein the second belt (4) is configured as a V-ribbed belt.

13. The auxiliary unit drive (1) according to any one of the preceding claims, wherein the auxiliary unit drive (1) is provided as an auxiliary unit drive (1) for an internal combustion engine for a motor vehicle.

14. Motor vehicle, preferably commercial vehicle, comprising an auxiliary unit drive (1) according to any of the preceding claims.