SE1550817A1 - Drive system equipped with belt circuits - Google Patents

Abstract

SUMMARY The invention relates to a drive system (1) (8), for a driven unit for power transmission (7), for example one between a drive shaft e.g. (12) from an engine power take-off (4), charge air compressor or the like, and an axle AC compressor, and preferably intended for heavy commercial vehicles with requirements for high torque transmitted and / or with high torque spikes, (5,6) The invention is achieved by the intermediate shaft ( 9) a movable yoke (17), (17) (5,6) comprising at least two belt circuits and an intermediate shaft (9) are arranged so that the yoke during tensioning the belt circuits is arranged to be displaced in the direction from the center axes of the driving and / or the driven unit. (13,15), (17) that, and that the yoke and the intermediate shaft (9) are arranged during clamping, automatically / self-adjusting rotate / rotate in relation to the central axes (13,15) of the driving and / or the drive unit in order to compensate possible angular errors in the position of these parts or to compensate for parallel displacements between the center axes (13,15) of the drive and the driven unit or to compensate for deviations in belt length between the first and the second the belt circuit (5,6) and thus still achieve a substantially equivalent belt tension in the two belt circuits (5,6) - (Figure 1)

Description

TECHNICAL FIELD The present invention relates to a drive system provided with at least two drive belts. The drive system is especially intended for power transmission between a driving unit, e.g. an engine, power take-off and a shaft of a driven unit, for example an AC compressor, charge air compressor or the like. The invention is particularly intended for heavy commercial vehicles with high transmitted torques and / or which can handle high momentary torque spikes. The invention relates in particular, but not necessarily, to drive systems in which the shaft of the power take-off and the shafts of the driven unit are angled relative to each other and / or offset laterally relative to each other. The invention also relates to a vehicle arranged with a drive system according to the invention.

BACKGROUND ART In many contexts, it is necessary to operate an attachment unit in a vehicle with the aid of the vehicle's engine. A common solution would be to place the driven unit axially in line with the power take-off of the driving unit, the motor, and to connect the two units with an intermediate shaft. In vehicles, it is common to transmit the mechanical force via a unit drive-equipped system or drive system equipped with belt circuits, ie. with at least one drive belt. The driven unit can, for example, be a compressor in an AC system and the driving unit can e.g. be an internal combustion engine. But many other applications are of course common / possible for this type of torque transmission.

In the example mentioned, the internal combustion engine generates the mechanical force via its power take-off, i.e. via its drive / output shaft. The driven unit is normally driven directly by the engine or via a gearbox. Normally, efforts are made to place the driven unit directly in the power take-off extension, so that the shafts of the drive motor and the drive unit are substantially placed axially in line with each other, i.e. so that their center axes coincide. However, this shortcoming gives rise to a number of practical construction difficulties in various concrete applications.

Thus, there are often, so-called for various reasons, alignment errors between the driving and the driven unit, i.e. the center lines of the two units do not completely coincide, the unit units are mounted with a certain deviation in relation. It can be an angular deviation or that in relation to each other. the axes are offset laterally, parallel, to each other. In this case, an axis placed between the driving and the driven unit must compensate for this. The service life of the shaft, and other components included in the drive system, depends on how the choice of the center lines of the shafts coincides and the choice of intermediate shaft also affects the operating conditions of the system.

A large unit, for example an AC compressor for a bus, can be very faithful / heavy to start and / or be equipped with a coupling that is activated very quickly / intermittently. The drive system can give rise to great stresses and generate high torque spikes which the components in the drive system must be dimensioned to withstand, ie not only the drive shaft itself but also other components in the transmission.

A driven unit that suddenly stops for one reason or another exposes the entire drive system, with motor and drive shaft, to very high loads unless a break pin, which fails due to certain stress and high loads, is arranged in the construction. Such a stop gives an imminent risk of component failure or, in the event of a breakage pin, a breakdown of operation and a subsequent repair action.

If the driven unit is placed close to the PTO shaft / output shaft, this often limits the freedom in the choice of drive shaft and to dimension the drive shaft with a sufficient diameter so that it can handle all the load drops that may occur.

Depending on the components of the drive system, the selected shaft can also have a significant effect on the drive system natural frequency and make it difficult to separate excitation frequencies from natural frequencies. This in turn can generate large torque fluctuations in the drive system which results in the system failing. Space limitations in conjunction with the high load of the driven unit and the dynamics of the drive system in general, can lead to difficulties in dimensioning a drive system with a normal drive shaft without problems with co-oscillations and too limited service life of the components.

In addition, many drive shafts allow only a limited deviation from the nominal distance between the driving output shaft, This power take-off, and the shaft of the driven unit. as mentioned, can be difficult to fulfill in some environments, such as. in a vehicle where the design space and packing density are often a problem that limits the possible placement and dimensions of the components, e.g. various solutions have previously been proposed to solve naming problems so that a things transmission of a mechanical drive can take place between a drive and a drive unit regardless of whether their axes are placed in line with each other or not.

US2013 / 0172138 describes, for example, a device for transmitting a mechanical torque, a power transmission, between a driving and a driven assembly comprising at least one pulley. The driven unit has, for example, an air compressor for supplying charge air to an internal combustion engine. The construction consists of a first and a second belt transmission and a shaft between them which connect the pulleys in the two belt circuits. The object of the invention is that the construction should be able to transmit a mechanical torque at a certain gear ratio up to a predetermined engine speed and then transmit the torque at another gear ratio. The purpose is not to compensate for axles that are angled in relation to each other.

JP02119636 discloses a power transmission to an auxiliary unit which may, for example, be a compressor for a single-combustion engine. The construction comprises a first and a second belt transmission and a shaft placed therebetween. Nor does this construction show any clamping device which can compensate for angled shafts or for drive belts of different lengths.

JP6274139 discloses a transmission comprising a front and a second belt transmission and an axle located therebetween for driving an attachment at an internal combustion engine. Neither this device shows a construction in which the intermediate shaft can be displaced in the tensioning of the belts or the dorsal tensioning device can compensate for the driving the shaft is angled / skewed in relation to the driven shaft.

Prior art in this field does not detect and thus does not solve the problem of clamping two belt circuits for equivalent belt tension with a self-adjusting mechanism, which compensates for cases where driven and driving shafts are offset or angled relative to each other.

SUMMARY OF THE INVENTION AND ITS OBJECTIVES An object of the invention is to solve the above-mentioned problems and to demonstrate a drive device which can transmit mechanical moments between shafts which are offset or angled in relation to each other and compensate for such asymmetries in a simple and flexible manner so that equivalent belt tension is still achieved in both belt circuits. Correct belt tension with longer belt life and ensures the desired torque transmission in the installation.

A further object of the invention is that the construction should be simple and cost-effective to manufacture, assemble and maintain.

A further object of the invention is that the tensioning of the belt circuits can be done easily and in one operation.

These and further objects and advantages are achieved according to the invention by a device defined by the features set forth in the characterizing part of the independent claim 1.

The present invention relates to a structural solution which is used for using a conventional drive shaft, or a single belt circuit with a belt, between the driving and the driven assembly, using a drive system with two belt circuits. The first belt circuit is arranged to run between the output drive shaft, the engine power take-off, and an intermediate shaft, while the second belt circuit is arranged to run from the intermediate shaft to the driven unit. Using two belt circuits provides a row distributor and eliminates difficulties that normally arise, especially when the design space in the current application limits the dimensions that can be used for the drive shaft.

A further and perhaps more useful method is that the tensioning belts, by tensioning the system, displace the center axes of the intermediate shaft away from, radially out of, the driving and the driven assembly. In order to compensate for pre-deviations in belt length between the first and the second belt circuit, and to compensate for any angular deviations from the nominal unit location, the invention makes it possible for the intermediate shaft to self-adjustably rotate / angle the sub-tensioning process so that each belt tension / belt is achieved. defiant geometric deviations in the location of the units in relation to each other. When sufficient belt tension has been reached in the boat belts, the intermediate shaft is locked from rotating and moved relative to the pulleys by means of locking screws.

Each belt circuit may consist of one, two or more belts depending on the loads to be transferred in the drive system. It is also possible to use different belt types in the drive system according to the invention. Increased number of belts in each belt circuit, however, increases the difficulty of achieving an equal belt tension in all belts.

The unloading according to the invention, using belts, entailed a reduced requirement for alignment / positioning between the drive shaft and the shaft of the driven unit and the invention, the belt tensioner can simultaneously simultaneously tighten both belt circuits and partly compensate for angular and bearing deviations between the driven and driven units and shoulders. In cases where a drive shaft would normally be used, but where this is not possible due to prevailing space limitations, unit load or system dynamics, the drive system with belts and intermediate shaft according to the invention could be used to advantage.

In the invention, the intermediate shaft is displaced away from the center lines of the driving and the driven shaft and forms a robust adjusting mechanism which requires only a single clamping device for simultaneous clamping of both belt circuits.

The clamping device compensates for positioning errors in the intermediate shafts and also for certain differences in belt length in those boat belt circuits by allowing the intermediate shaft to be rotated during the belt tensioning process itself.

Further features and advantages of the invention will become apparent from the following, more detailed description, of the invention, and from the accompanying drawings and other claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is described in more detail below in some preferred embodiments with reference to the accompanying drawings.

Figure 1 shows a perspective view of an installation on a single motor part of a drive system according to the invention, has for operation also a compressor, provided with two belt circuits and a belt tensioner for simultaneous / synchronous clamping of both belt circuits.

Figure 2 shows the same picture as in figure 1 but where the compressor is removed to show more clearly the construction of the drive system.

Figure 3 shows a perspective view of the drive system including the engine part's power take-off.

Figure 4 shows the drive system in a side view showing the details of the belt tensioner better.

Figures 5a-b show a detail section through the belt tensioner, showing how the side edges of the plate are rounded in order to allow compensation for inboard inclination between driving and driven assembly.

Figure 6 shows essentially a horizontal section through the drive system.

Figures 7a-c show the function and attachment of the clamping screw to the movable / rotatable yoke.

DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 shows a perspective view of a possible mounting of a drive system 1 according to the invention with integrated belt tensioner 2, placed on a motor part 3 for operation of a driven unit 4, a compressor. Two belt circuits 5, 6 are arranged to couple the power take-off of the clutch motor 7 via a drive shaft 8 to the drive unit 4 by means of an intermediate shaft 9. A first belt circuit 5 is arranged to mechanically, via two belts 10a, b, couple the intermediate shaft 9 to the drive shaft 8. indirectly to the motor power take-off 7, also with two belts 10c, d, and a second belt circuit 6, are arranged to connect the intermediate shaft 9 to the drive unit 4, the input shaft of a compressor. All belts 10a-dlops in pulleys 11a-d arranged on the drive shaft 8, the intermediate shaft 9 and the shaft of the driven unit (not shown). Preferably, V-belt type belts 10a-d are used as they function well even at relatively large inclines of the intermediate shaft 9 relative to the driving shaft 8 and / or the driven shaft 12 and their pulleys 11a-d.

Figure 2 shows the same picture as shown in Figure 1 but has the driven unit, the compressor, removed to show more clearly the construction of the entire drive system 1 and how the second belt circuit 6 conveys the force from the intermediate shaft 9 via to the driven unit pulley 11d and shaft 12. In the figure the center shafts 13-15 have also been dashed in. Figure 3 shows a perspective view of only the drive system 1including the engine part power take-off 7 which is mechanically connected to the drive system 1 via an integrated gearbox 16. In that case parallel displacement and angular error between drive shaft 8 and driven shaft 12 are possible. offset when tightening the belt circuits 5,6, or at least an equivalent belt tension is obtained in both belt circuits 5,6.

The rotation of the power take-off 7 is thus transmitted to a front pulley 11a, which is provided with two keyways. Via a first pair of V-belts 10a, b the torque is transmitted to a second pulley 11b (partially obscured) arranged on the intermediate shaft 9 which is mounted substantially, but not necessarily completely, parallel to the drive shaft 8. On the same intermediate shaft 9 a third pulley 11c is arranged, also the one with two keyways, on which runs another pair of V-belts 10c, d. These V-belts 10c, d the upper torque of a fourth pulley 11d mounted on the drive assembly 4, the compressor.

Figure 4 shows the drive system 1 in a side view showing the details of the belt tensioner 2 better. The belt tensioner 2 mainly consists of a movable / rotatable yoke 17 in which the intermediate shaft 9 is mounted. In the outer ends of the intermediate shaft 9, pulleys 11b, c fixedly arranged, are provided with two grooves each for V-belts 10a-d. The pulleys 11b, c rotate with the intermediate shaft 9. The yoke 17, and thus the intermediate shaft 9, is displaceable via two elongate recesses 18a, b in which two screws 19a, b are mounted. The yoke 17 is displaced with the aid of at least one clamping screw 20. When the locking screws 19a, the tightened hook 17 is locked against the drive bracket fixed bracket 21 and the locking screws 19a are loosened, the yoke 17 and the intermediate shaft 9 can be displaced towards or away from the drive shaft 8 and the shaft. 12. If the yoke 17 is displaced from these shafts 8,12, the belt circuits 5,6 and the belts 10a-d are tensioned and the yoke 17 is displaced against the driving or driven assembly slackens the belts 10a-d and loses the ability to transmit a torque.When the belts 10a-d are tensioned sufficiently tighten the locking screws 19a, b and lock the yoke 17 relative to the bracket 21.

The recesses 18a, b can be formed slightly wider the diameter of the locking screws 19a, b, which facilitates that the yoke 17 can rotate / rotate during the clamping so that the belts 10a-d in both belt circuits 5,6 are tightened with substantially the same force in the case of the distance between the center axes 13-15. for the shafts 8, 12 of the driving and the driven unit and the intermediate shaft 9, arolica large, due to angular differences or due to mutually offset placement of the drive shaft 8 and the shaft 12 of the driven unit 4.

Figure 5a shows a detailed section through the drive system 1 and the belt tensioner 2, showing how some of the support or side edges 22a, b arranged in the fixed bracket 21, b rounded / arcuate to facilitate that the yoke 17 can be rotated slightly relative to the bracket 21 in order to compensate for a mutual inclination or displacement between the drive shaft 8 and the driven assembly 4, and their center shafts 13,15. The grooves 18a, b of the locking screws 19a, b are designed so wide that the yoke 17, when rotated, is not prevented by the screws 19a, b. By displacing / turning the yoke 17, the boat belt circuits 5,6 can compensate for changes in length of the belts 10a-d and / or compensate for parallel displacements between the shaft 8,9,12 or angular errors between the drive shaft 8 and the shaft 12 of the driven unit. The clamping screw 20 is mounted in a single fixture 23 and threaded through a nut with conical washer 24 and presses, when tightening / clamping, against the yoke 17. Through the conical washer 24 it is allowed that the clamping screw 20 can be angled in the fastener 23 and adapt to the angle of the yoke 17.

Figure 5b shows in principle and in more detail an abutment surface / plate 25 arranged between the yoke 17 and the bracket 21 (figure 5a), in fact a part of the bracket 21, and the design 11 thereof with rounded / arcuate side edges 22a, b which allowed the yoke 17 can be rotated / rotated slightly in relation to the bracket 21 during the tensioning of the belt circuits 5,6 and the belts 10a-d (see figure 5a). The plate 25 is arranged on or integrated in the bracket 21 and formed with side edges 22a, b. The yoke 17 is arranged with support edges 27a, b which in mounted abut against the side edges 22a, b of the plate or in each case restrict the lateral mobility of the yoke 17, i.e. in the axial joint of the intermediate shaft 9.

The indicated elongate recesses 18a, b for locking screws 19a, b the yoke 17 make the yoke 17 displaceably substantially transverse to the intermediate shaft 9 and in relation to the bracket 21 and the locking screws 19a, b. And the fact that the locking screws 19a, b have a slightly smaller diameter than the width of the recesses 18a, b contributes to the attic 17 can be rotated several degrees, up to about f10 degrees, in relation to This thus meant that the yoke 17, but preferably up to about f5 degrees, the bracket 21 and the plate 25. when tightening the clamping screw 20, automatically / self-adjustingly rotated / rotated to an angular layer for the intermediate shaft 9 which compensates for parallel displacements or angular errors in the position of the shafts 8,9,12 in relation to each other and / or for longitudinal changes that may occur in the belts 10a-d. Figure 6 shows a substantially horizontal section, according to AA in figure 4, through the drive system 1. It is clearer how the intermediate shaft 9 rotates in a bearing 26 arranged in the yoke 17 and how the plate 25 is fitted in the upper part of the yoke 17 in a recessed 28, preferably with straight inner support edges 27a, b (see Figure 5b) to allow the yoke 17 to be rotated and displaced in a direction substantially transverse to the central axis. ln 9 when tightening the belts 10a-d, but not moved laterally, i.e. in the axial joint of the intermediate shaft 9. The yoke 17 is fixed to the plate 25 with, for example, two locking screws 19a, b. Figures 7a-c show the function and fastening of the clamping screw 20 against the rudder / rotary yoke 17. Figure 7a shows the position of the yoke 17 of the belt pulley 10ä-d is equally long and the distance from the central shaft to the central shaft 14 to the central shaft 13, 15 to the drive shaft and 8 (see figure 1) and the driven egg unit 4 (see figure 1) is the same. Figures 7b and 7c show clamping positions where the bed circumferences 5,6 are not the same length here or where the distance between the axes 13, 14 and 15 is not the same length. The fastening of the clamping screw20 can advantageously be arranged so that it is allowed to rotate with the yoke 17 in order to reduce the stress in the clamping screw20 and not to negatively affect the self-adjusting function of the clamping shaft 17.

The above description is in the first instance intended to facilitate the understanding of the invention. The invention is of course not limited to the stated embodiments, but even further aspects of the invention are possible and conceivable within the scope of the inventive concept and within the scope of subsequent patent claims.

Claims (10)

Drive system (1) for power transmission between a drive shaft (8), (7), (12) for a, for example, an AC compressor, charge air- e.g. from an engine power take-off and a shaft (4), compressor or similar, driven unit and preferably intended for tongue including at least two belt circuits (5,6) (9), commercial vehicles, and an intermediate shaft characterized by, - that the intermediate shaft (9) (17) are arranged in a movable yoke (17), - that the yoke and its intermediate shaft (9) (5, 6) of the drive shaft (8) (17) are displaced in the direction from (12) when tensioning the belt circuits, are arranged that and / or the driven the shaft of the unit and - that the yoke and the intermediate shaft (9) are arranged to, in the case of clamping, automatically / self-adjusting rotate / rotate relative to the central axes (13, 15) of the driving and / or the driven unit in order to compensate for any mutual angular error in the position of these parts or to compensate for parallel displacements between the drive shaft (8) and the shaft (12) of the driven unit or to compensate for deviations in belt length between the first and the second belt circuit (5,6) and thus still achieve a essentially similar constant belt tension in the two belt circuits (5,6). Drive system (1) according to claim 1, characterized by, (17) rotatable and lockable in (21). that the yoke is displaceable, relative to the fixed bracket of the drive system (1) Drive system (1) according to claim 1 or 2, characterized in, (17) in that a clamping screw (20) relative to the bracket is arranged to displace the yoke (21). Drive system (1) according to one of the preceding claims, characterized in that 14 (25) (21) forms an abutment surface between the yoke (17), the yoke (17) (17) having a plate and the bracket provided with support edges (27a, b). ) substantially transverse to the intermediate shaft (9) (17) which allows the yoke to be displaced in a direction which limits the mobility of the yoke in the axial direction of the intermediate shaft (9). Drive system (1) according to one of the preceding claims, characterized in that (17) the yoke is arranged to be able to rotate / rotate up to f10 degrees, preferably f5 degrees, relative to the bracket (21). Drive system (1) according to one of the preceding claims, characterized in that it comprises pulleys (11a-d). that the belt circuits (5.6) Drive system (1) according to one of the preceding claims, characterized in that the pulleys (11a-d) have belts (10a-d) arranged for at least two each. Drive system (1) according to one of the preceding claims, characterized in that the belt circuits are provided with belts (5,6) (10a-d) of the V-belt type. Drive system (1) according to one of the preceding claims, characterized in that the plate (25) (21) is arranged on and / or as part of and that its side edges (22a, b) are rounded / arcuate to allow yoke (17) (5,6) - console night rotate / turn when tightening the belt circuits 10. Vehicles equipped with a drive system (1) 1-9. according to the claims