EP2097646A1

EP2097646A1 - Pump

Info

Publication number: EP2097646A1
Application number: EP07856226A
Authority: EP
Inventors: Daniel HÖSCHEN; Robert Deipenwisch
Original assignee: Ixetic Hueckeswagen GmbH
Current assignee: Magna Powertrain Hueckeswagen GmbH
Priority date: 2006-11-23
Filing date: 2007-11-22
Publication date: 2009-09-09
Also published as: DE112007002185A5; JP5347184B2; JP2010510435A; WO2008061749A1

Abstract

The invention relates to a pump, especially a vane-cell vacuum pump, for motor vehicle servobrake systems, said pump comprising a rotor (7) which is rotatably driven by a drive by means of a wrap spring clutch (23).

Description

pump

description

The invention relates to a pump, in particular vane-type vacuum pump, for motor vehicle brake booster systems according to the preamble of claim 1.

Pumps of the type discussed here are known (EP 1 277 960 A2). They serve to provide a vacuum for motor vehicle brake booster systems and have a rotor which is set in rotation by a drive. The coupling between the rotor and the drive takes place via a coupling with a wrap spring, which is wound in such a way that it transmits the drive torque when the drive rotates in the direction of pump rotation. If the drive turns against the direction of pump rotation, the wrap spring may slip. Such a coupling ensures that the rotor is not driven in the wrong direction of rotation if the drive unintentionally runs backwards. Incidentally, the wrap spring can be designed so that the coupling slips from a desired maximum torque and the rotor is not overloaded. During operation of the motor vehicle, the pump is constantly driven, which leads to increased energy consumption and internal combustion engines to increased pollutant emissions.

The object of the invention is therefore to provide a pump which does not have this disadvantage.

To solve this problem, a pump is proposed which comprises the features mentioned in claim 1. It has a rotor, which via a wrap spring clutch from a drive in Rotation is offset, for example, to generate negative pressure in a motor vehicle brake booster system. The wrap spring cooperates with the rotor of the pump and is wound so that it is tightened in the pump rotation direction on the rotor and a stub shaft of the drive upon rotation of the drive, so that a torque of the drive is transmitted to the rotor. The pump is characterized by a switching device, which widens the wrap spring in a functional position, so that it no longer rests so firmly on the stub shaft and / or on the rotor and no torque is transmitted from the drive.

In another functional position, the switching device does not prevent the contraction of the wrap spring, so that a coupling of the rotor is given to the drive and this is rotationally driven.

This embodiment has the advantage that the pump can be switched off when a desired negative pressure is reached in the motor vehicle brake booster system. The drive is not loaded further, so that no unnecessary energy loss occurs.

Preferred is a pump, which is characterized in that the switching device comprises a switching element. This is movable in the direction of the longitudinal axis of the wrap spring and cooperates with a first end of the spring. It has a button which is inclined at an angle to the longitudinal axis of the wrap spring, so that upon a displacement of the switching element in the direction of the longitudinal axis of the wrap spring whose first end is displaced, namely in a functional position in which the spring is rotated back against the drive direction of the stub shaft becomes, so that their inner diameter increases. This prevents the transmission of torque from the stub shaft to the rotor: The pump is switched off. In a further preferred pump it is provided that the switching element is designed as a switching sleeve which is arranged concentrically to the longitudinal axis of the wrap spring. This design is characterized by a particularly compact design.

In a further preferred pump it is provided that the switching element of the switching device is hydraulically actuated. It is thus a simple and inexpensive realization of the switching device allows.

Another pump is preferred because the switching device has an elastic element. This forces the switching element into a functional position in which the wrap spring couples the rotor to the drive. This structure is particularly simple and therefore less prone to failure.

In a further preferred pump, it is provided that the switching device is switched as a function of the pressure in the motor vehicle brake booster system. Thus, the pump can always be deactivated when a sufficient pressure, in particular negative pressure is generated.

In a further preferred pump, an oil supply is provided which is also interrupted when the drive of the rotor of the pump is interrupted.

In a further preferred pump, it is provided that the switching sleeve forms a pressure chamber with a housing surrounding the rotor. This realizes a particularly compact construction of the pump. Further embodiments of the pump will become apparent from the dependent claims.

The invention will be explained in more detail below with reference to the drawings. Show it:

1 shows a schematic diagram of a first embodiment of a pump with a switching device in longitudinal section,

Figure 2 shows a switching element of the switching device in an enlarged perspective view.

Figures 3 to 14 different embodiments of a pump with a switching device and

Figure 15 is an end of a wrap spring in side view.

From the schematic diagram in Figure 1, a first embodiment of a pump 1 with a housing 3 can be seen, which encloses a pump chamber 5, for example, receives a wing, not shown here a vane pump, which is driven in rotation by a rotor 7. The pump is used, for example, to generate negative pressure in a motor vehicle brake booster system. It can be supplied by an oil pump 9 via a line 11 and via an introduced into the housing 3 bore 13 with oil, which serves to lubricate the pump 1. This will be discussed in more detail below.

The rotor 7 is mounted in a concentric with the rotor and the axis of rotation 15 arranged bearing lug 17. The bore 13 in the housing 3 opens into the contact region between the bearing lug 17 and the rotor 7 in order to ensure the lubrication of the rotor 7. The rotor 7 has at its side facing away from the pump chamber 5, projecting from the bearing neck 17 end a cylindrical projection 19 which has a relation to the other rotor 7 reduced outer diameter and on which a wrap 21 of a wrap spring 23 is placed. Their inner diameter substantially corresponds to the outer diameter of the projection 19, so that in the relaxed state of the wrap spring 21, low frictional forces act between it and the projection 19.

The length of the wrap spring 21 is - measured in the direction of the axis of rotation 15 - chosen so that it projects beyond the projection 19 and receives a stub shaft 25 of a drive not shown here. The outer diameter of the stub shaft corresponds to the outer diameter of the projection 19, so that the outer surfaces of lug 19 and stub shaft 25 are aligned with each other and are embraced by the wrap spring 21.

The stub shaft 25 has an extension 27 which engages in a recess 29 which is introduced from the right into the projection 19 of the rotor 7. The outer diameter of the extension 27 is matched to the inner diameter of the recess 29, that the extension 27 is rotatably mounted in the recess 29 friction. Suitably, the extension 27 is secured axially against withdrawal from the recess 29. By way of example, a snap ring 31 is provided here, on the one hand engages in a groove 33 which is introduced into the inner surface of the recess 29, on the other hand in a groove 35 which is introduced into the outer surface of the extension 27.

If the stub shaft 25 of the drive is set in rotation in a first direction, namely in the working direction of the pump 1, the frictional forces act on the wrap spring 21, which is wound in this case on the stub shaft 25 and on the neck 19 is tightening. This allows a torque from the drive, so be transferred from the shaft stub 25, on the projection 19 and thus on the rotor 7, so that, for example, a wing in the pump chamber 5 is set in rotation and a negative pressure is built up.

The wrap spring 23 is designed so that the wrap spring 21 is expanded and relaxed in the opposite direction by the frictional forces between the outer surface of the stub shaft 25 and the inner surface of the wrap spring 21, whereby its inner diameter at least in the region of the stub shaft 25th expands so that it can no longer transmit torque to the wrap spring 21 and thus to the projection 19 of the rotor 7.

The pump 1 is provided with a switching device 37 which serves to switch off the pump 1 even when the drive is activated, that is to say when the shaft stub 25 is rotated in the drive direction in which the wrap spring 21 is tightened. When using the pump 1 in a motor vehicle, this is usually driven by the engine, in particular the internal combustion engine, by the stub shaft 25 is set in rotation, in the direction in which the wrap spring 21 is contracted and thus on the Tighten outer surface of stub shaft 25. At the same time sets so that the wrap 21 also to the outer surface of the projection 19 so that it is offset by the drive via the wrap spring 21 in rotation. To actuate the wrap spring 23 so that no torque is transmitted to the rotor despite rotation of the shaft stub 25, the switching device 37 is provided with a switching element, which is designed here as a switching sleeve 39 which is arranged coaxially to the axis of rotation 15 and the Rotor 7 and the coil spring 21 engages, also the stub shaft 25. The length of the switching sleeve 39 can be chosen so that that it still overlaps parts of the drive, not shown here, of which only the stub shaft 25 is reproduced here.

The length of the switching sleeve 39 on the other hand chosen so that it protrudes with its left end 41 in the bearing lug 17 of the housing 3 and there sealingly abuts with an outwardly from the rotation axis 15 directed away annular bead 43 on the inner surface 45 of the bearing lug 17. The end face 47 of the bearing lug 17 is sealed by a sealing plate 49 which rests with its inner edge 51 sealingly against a peripheral surface 53 of the switching sleeve 39. Between the sealing plate 49 and the annular bead 43 of the switching sleeve 39 so that a pressure-tight closed space 55 is created in the interior of the bearing lug 17, which is connected via a bore 57 in the housing 3, here in the bearing lug 17, with a line 59. The sealing plate 49 may be made of metal. At the left end 41 of the switching sleeve 39 is a here designed as a helical spring 61 elastic member is provided, which is supported on the one hand on the rotor 7 and on the other hand on the left end 41 of the shift sleeve and a rightward biasing force on the shift sleeve 39 exerts. This rotates together with the rotor 7, when it is driven; this also applies to the coil spring 61.

The switching sleeve 39 is seen in the axial direction, ie in the direction of the axis of rotation 15, formed on the rotor 7 and with respect to the wrap spring 21 movable. If a medium, preferably oil, is introduced under pressure into the space 55, as explained in more detail below, via the line 59 and the bore 57, the switching sleeve 39 shifts against the force of the helical spring 61 from a certain overpressure in the space 55 to the left in a first functional position. In Figure 1, a functional position of the switching sleeve 39 is reproduced, in which this at least over a certain range was shifted to the left against the force of the coil spring 61. If she moves further to the left, she finally reaches the first functional position. In this, the wrap spring 21 is widened so that it no longer rests on the outer surface of the shaft mute 25 at least. This will be discussed in more detail below.

If the space 55 depressurized or subjected to a pressure which exerts a leftward force on the shift sleeve 39, which is smaller than the biasing force of the coil spring 61, the shift sleeve 39 is moved by the coil spring 61 to the right until the annular bead 43rd at the sealing plate 49 strikes inside. This therefore serves as a limitation of the displacement path of the switching sleeve 39 to the right. If the switching sleeve 39 abuts the sealing plate 49, then it has assumed its second functional position: The switching sleeve 39 does not influence the wrap spring 21. When the shift sleeve 39 is displaced to the right, oil present in the space 55 is pushed out via the bore 57 and the line 59, for example into a tank.

FIG. 1 also shows that the switching sleeve 39 has a button 63 which interacts with a first end 65 of the wrap spring 21, which is directed radially outwardly beyond the remaining circumferential surface of the wrap spring 21, ie away from the rotation axis 15. The button 63 is part of a first recess 67 in the wall 69 of the switching sleeve 39th

The wrap spring 21 has a relative to the axis of rotation 15 on the peripheral surface of the wrap spring outwardly projecting second end 71, which is arranged in a second recess 73 in the wall 69 of the switching sleeve 39.

The length of the recesses 67 and 73 - measured in the direction of the axis of rotation 15 - can be chosen so that one of the left End 41 facing boundary wall of one or both recesses 67, 73 abuts the protruding into the recess end of the wrap spring 21 when the switching sleeve 39 has reached its second functional position. It can therefore be realized in this way a stop for the switching sleeve 39.

Figure 2 shows a perspective view of the switching sleeve 39 of the switching device 37 in high magnification. In this reproduction, the left end 41 of the switching sleeve 39 is in the foreground. Clearly visible here are the annular bead 43 and the adjoining circumferential surface 53 of the switching sleeve, which forms the bottom of a groove 75 introduced into the wall 69 from the outside. At a distance from the left end 41, the first recess 67, which has the button 63, is introduced into the wall 69. In this recess engages the first end 65 of the wrap spring 21, which is not shown here in Figure 2.

At a suitable location in the wall 69, here approximately diametrically opposite the first recess 67, the second recess 73 is introduced, which is formed as a slot extending parallel to the central axis of the switching sleeve 39, which coincides with the axis of rotation 15 shown in FIG is. In this engages the second end 73 of the wrap spring 21, not shown here.

From the explanations of the recesses 67 and 73 in the wall 69 of the switching sleeve 39, the following becomes clear: If the switching sleeve 39 is moved coaxially to the rotor 7 and thus to the rotation axis 15, the second end 71 of the wrap spring 21 can slide in the second recess 73, without it being moved in the circumferential direction of the shift sleeve 39.

If, as shown in FIG. 1, the switching sleeve 39 is moved to the left by an overpressure in the space 55, then Nem angle to the rotation axis 15 inclined button 63 almost like a wedge gear on the first end 65 of the wrap 21 a. It becomes clear that, in the case of a shift to the left in FIG. 1, the button 63 acts on the first end 65 of the wrap spring 21 so that it is displaced to the right according to the viewing direction in FIG. 2, ie rotated clockwise. The button 63 is inclined such that the first end 65 of the wrap spring 21 is rotated during this displacement of the shift sleeve 39 so that the inner diameter of the wrap spring widened at least in the region of the stub shaft 25 of the drive, so that the latter no longer has any torque Wrap spring 21 and thus can be transmitted to the rotor 7.

If the wrap spring 21 is wound in the opposite direction, the button 63 would have to be inclined in mirror image to the illustration in FIG.

It is clear that the second recess 73 exclusively serves to hold the second end 61-seen in the circumferential direction of the shift sleeve 39. In principle, the second recess can thus be dispensed with and the second end 71 can be held in a different manner.

However, it is also conceivable to provide a button in the region of the second recess 73, which is inclined such that the second end 71 of the wrap spring 21 is displaced to the left in the circumferential direction of the shift sleeve when the shift sleeve 39 is displaced so that the The wrap spring 21 widens, at least in the area of the rotor 7.

Overall, it can be seen that a button of the type mentioned here can also be provided only in the region of the second recess, while the first recess is essentially flat. runs parallel to the axis of rotation 15. By suitable design of the recesses, it is ensured on the whole that the inner diameter of the wrap spring 21 increases upon activation of the shift sleeve 39, at least in the region of the stub shaft 25, and thereby decouples the drive from the pump 1. By differently strongly biased areas in the contact surfaces of the wrap spring 21 on the rotor 7 and the stub shaft 25, a defined area for lifting the wrap spring 21 may be provided when the shift sleeve 39 is activated according to Figure 1 and displaced to the left.

By the coil spring 61 ensures that the switching sleeve 39, if there is no or only a slight pressure in the room 55, is urged into a functional position, namely the second functional position in which the drive via the stub shaft 25 with the projection 19 of the rotor. 7 is coupled and the pump 1 is driven.

The switching device 37 is preferably controlled by the pressure generated by the pump 1, here by the negative pressure in the power tool brake booster system. This is detected via a measuring line 77, which is connected to the working side, ie the negative pressure side, of the pump 1. The negative pressure acts here on a valve device 79 belonging to the switching device 37, which comprises a 4/2-way valve. This assumes different switching positions as a function of the pressure detected via the measuring line 77:

If a sufficient negative pressure is detected, the control piston of the 4/2-way valve is moved to the position shown in Figure 1. Thus, the oil pump 9 is connected to the conduit 59, the bore 57 and the space 55, so that a pressurized medium, preferably hydraulic oil, is conveyed into the space 55. This overpressure causes the switching sleeve 39 in the basis of 1, in which the button 63 engages with the first end 65 of the wrap spring 21 and displaces it so that the inner diameter of the wrap spring 21 is widened at least in the region of the stub shaft 25. From the illustration according to FIG. 1 it can be seen that the first end 65 of the helical spring 21 has not yet reached the end of the first recess 67 opposite the left end 41. The shift sleeve 39 can thus be moved to Figure 1 even further to the left to see a safe decoupling between drive and rotor 7 to ensure.

From Figure 1 it can be seen that in this functional position of the 4/2-way valve, the bore 13 in the housing 3 is depressurized, preferably with a tank 80 is connected. The oil supply to the pump 1 via the oil pump 9 is thus interrupted. If the pressure generated by the pump 1 falls below a desired value, this is ascertained via the measuring line 77 and the valve device 79 is activated. The control piston of the 4/2-way valve is displaced to the left in relation to the position shown in FIG. As a result, the oil pump 9 is connected to the bore 13, so that the oil supply of the pump 1 is ensured. At the same time the space 55 is connected via the bore 57 and the conduit 59 to the tank 80; This results in a pressure drop in the space 55. The helical spring 61 can now displace the control sleeve 39 to the right until the annular bead 43 abuts the inside of the sealing plate 49 and the control sleeve 39 assumes its second functional position. In this, the button 63 no longer acts on the first end 65 of the wrap spring 21, so that they are clamped by the frictional forces acting between the inner surface and the outer surface of the stub shaft 25, both on the stub shaft 25 and on the projection 19 of the rotor 7 can be; the pump 1 is again coupled to the drive. Overall, it turns out that a conventional wrap spring clutch 23 is easily switchable. The drive of the pump 1 can be switched off pressure-dependent, by acting on the wrap spring 21 so that it is brought into a relaxed position and transmits no more torque from the stub shaft 25 on the projection 19 of the rotor 7.

The construction of the switchable coupling is simple and therefore inexpensive to implement.

Figure 3 shows another embodiment of a pump with a wrap spring clutch in longitudinal section. Identical parts are provided with the same reference numerals, so that reference is made to the description of the preceding figures.

In the embodiment of the pump 1 according to Figure 3, the housing is omitted. It has a rotor 7, which is arranged on the right in Figure 3 and is rotated by a drive, not shown here in rotation. The torque of the drive is introduced into a clutch bell 81, which is supported on at least one bearing 83. For example, while the right end 85 of the rotor can receive vanes located in a pump space, not shown, and convey a medium, the left end 87 of the rotor 7 is designed to engage the interior of the clutch bell 81. The rotor 7 is hollow, so that it can accommodate the wrap spring 23 at least partially. This comprises a wrap spring 21, whose left portion here is arranged inside the clutch bell 81, while its right portion is accommodated in the rotor 7. The clutch bell 81 has a receiving portion 89 in which the left portion of the wrap spring 21 is located and which comprises an inner diameter which is chosen so large that the wrap spring 21 does not touch the inner surface in the unloaded state. Will all- Recently, the wrap spring 21 widened, which will be discussed in more detail below, it touches with its peripheral surface, the inner surface of the receiving portion 89 so that its inner surface serves as a coupling surface.

The wrap spring clutch 23 comprises a switching device 37 with a setting body 91 which, like the switching sleeve 39 explained with reference to FIGS. 1 and 2, has recesses in its peripheral surface. Here, the first recess 67 can be seen, which extends in the direction of the axis of rotation 15 of the rotor 7 and the clutch bell 81 and in which a first end 65 of the wrap spring 21 engages.

The switch body 91 is provided on its peripheral surface with a second recess, which is discussed in more detail with reference to Figure 4 and in which a second end of the wrap spring 21 engages.

The switch body 91 is here formed in two parts, wherein the two connected here by means of a screw 93 parts 91a and 91b of the switch body 91 are rotated against each other. Since the first part 91a cooperates with the first end 65 of the wrap spring 21 and the second part 91b with the second end of the wrap spring 21, a defined spring preload can be set during the assembly of the wrap spring clutch 23 by a relative rotation of the two parts 91a and 91b. The two parts 91a and 91b are fixed to one another in the desired relative rotational position by means of the screw 93.

The interior 95 of the hollow rotor 7 is closed on the pump chamber 5 side facing by a closure member 97 pressure-tight. The switch body 91 is also hollow. In its inner cavity 99 is a preferably biased elastic element, here a coil spring 101, provided on the one hand on the closure member 97 and on the other hand supported on an inner wall 103 of the switch body 91. If this is in two parts, the inner wall 103 is part of the first part 91a of the switch body 91.

The switch body 91 is within the interior 95 in the direction of the axis of rotation 15 back and forth displaced. It is located in the illustration according to FIG. 3 in a first functional position, in which it is displaced maximally far to the right so that the switch body 91 bears against the closure element 97. Instead of the closure element, a separate stop for the switch body 91 can also be provided. The wrap spring 21 is - in the axial direction, ie in the direction of the central axis 15, seen - axially fixed so that its first end 65 is guided in a displacement of the switch body 91 within the first recess 67. Since the first recess 67 extends parallel to the axis of rotation 15, the first end 65 experiences no force acting in the circumferential direction during a displacement of the switch body 91, so that the spring preload is not changed via this first end 65.

The switch body 91 has at its right end a switching collar 105, which rests tightly with its circumferential surface on the inner surface of the inner space 95 of the rotor 7. The region of the switch body 91 adjoining the switching collar 105 on the left has a smaller outside diameter and lies close to a portion of the interior 95 of the rotor 7. This creates a space 55 which can be acted upon by a medium under pressure, preferably with oil. Thus act - in Figure 3 - from the left forces on the shift collar 105 so that the switch body 91 is displaceable at a pressure in the space 55 against the force of the coil spring 101 to the right in the position shown in Figure 3, when the pressure is chosen so large in that the force of the helical spring 101 is overcome. If the pressure in the room 105 drops below a value defined by the force of the coil spring 101, the switch body 91 is pressed by the coil spring 101 from the position shown in Figure 3 to the left. In this case, the first end 65 of the wrap spring 21 remains in the first recess 67. Since this is just in the direction of the axis of rotation 15, the wrap spring 21 undergoes no change in the bias.

The clutch bell 81 has a free space 107 whose inner diameter is selected so that the left end of the switch body 91, that is the second part 91b here, is at least partially received by the free space 107 when the switch body 91 is in the position shown in FIG is displaced to the left by the force of the coil spring 101.

The outer circumference of the switch body 91 is selected so that it is freely movable in the interior of the wrap spring 21 in the direction of the axis of rotation 15. The left portion of the wrap spring 21 is thus between the outer surface of the left part 91 b of the switch body 91 and the inner surface of the receiving portion 89 of the clutch bell 81st

The interior of the clutch bell 81 and the outer circumference of the rotor 7 are coordinated so that the rotor 7 are rotatably mounted together with the switch body 91 and the wrap spring 21 of the wrap spring 23 in the interior of the clutch bell 81. The left end 87 of the rotor 7 is supported via a further bearing 109 on the inner surface of the clutch bell 81. The relative rotation between the clutch bell 81 and the rotor 7 is influenced by the wrap spring 21 of the wrap spring clutch 23. If the wrap spring 21 arranged on the circumferential surface of the shift body 91 is widened by actuation of the shift body 91, its circumferential surface comes into contact with the inner surface of the clutch bell receiving portion 89 81 engaged so that a torque ment of the clutch bell 81 is transmitted to the rotor 7. In this case, the wrap spring 21 transmits forces introduced into the receiving section 89 via its first end 65 to the switch body 91, which is non-rotatably connected to the rotor 7. Since the wrap spring 21 is in frictional contact with the receiving portion 89, torque peaks are not transmitted to the rotor 7, because in this case the clutch bell 81 against the wrap spring 21 rotates. As a result, damage to the pump 1 can be avoided. This point of view applies to all embodiments explained here.

If the wrap spring 21 is tensioned, it bears against the circumferential surface of the switch body 91, as a result of which no frictional forces are transferred from the receiving section 89 to the wrap spring 21.

Figure 4 shows the explained with reference to Figure 3 switch body 91 in a perspective view. Identical parts are provided with the same reference numerals.

The switch body 91 is thus formed in two parts and comprises a first part 91a and a second part 91b. The first part is provided with the switching collar 105, whose outer diameter is larger than the remaining area of the first part 91a, in whose peripheral surface the first recess 67 is introduced, which extends in the direction of the longitudinal axis of the switch body 91, with the axis of rotation 15 of the rotor 7 coincides.

In the circumferential surface of the second part 91 b, a second recess 73 is introduced, which extends at an angle to the axis of rotation 15 and serves to receive the second end of the wrap spring 21, not shown here. The switching body 91 is, as explained with reference to Figure 3, at least partially in the interior of the not reproduced wrap 21st

If the switch body 91 is displaced in the direction of the axis of rotation 15 while the wrap spring 21 is fixed in the axial direction, a relative movement of the first end 65 of the wrap spring 21 takes place in the first recess 67 with respect to the second part 91b. It becomes clear that no movement of this end in the circumferential direction of the switch body 91 takes place. On the other hand, the second end of the wrap spring 21 located in the second recess 63 is displaced in the circumferential direction during an axial movement of the switch body 91. As a result, depending on the direction of movement of the switch body 91, the wrap spring 21 is more or less tensioned, so that its outer circumference changes accordingly, that is, increased or decreased.

This operation has been explained with reference to Figures 1 and 2 in connection with the switching sleeve 39, so that need not be discussed here in detail. It also becomes clear that the first recess 67 could extend at an angle relative to the axis of rotation 15, while the second recess 73 is arranged parallel to the axis of rotation 15. Also, both recesses 67 and 73 could be arranged at an angle to the axis of rotation 15, provided that during an axial movement of the switch body 19 relative to the fixed wrap spring 21 this would be biased more or less.

It can also be seen from FIG. 4 that the parts 91a and 91b of the switch body 91 are connected by means of the screw 93, which penetrates the two parts 91a and 91b in the axial direction. The engaging in the recesses 67 and 73 ends of the wrap spring 21 may be provided with sliders to reduce the friction between the spring ends and the recesses. This ensures smooth operation and reduces wear to a minimum.

From FIGS. 3 and 4 the following results:

The switch body 91 is formed here as a hydraulic piston. If the space 55 is supplied with hydraulic oil, which can be supplied, for example, by a rotor bearing, the switching body 91 is displaced against the force of the helical spring 101-in FIG. 3, to the right. The recesses 67 and 73 in the circumferential surface of the actuating body are designed and aligned so that during this movement of the switch body 91, the wrap spring 21 is tensioned so that reduces its outer diameter. As a result, the wrap spring 21 bears against the peripheral surface of the switch body 91 and lifts off from the inner surface of the receiving section 89, which acts as a coupling surface. As a result, no torques are transferred from the clutch bell 81 more to the wrap spring. The clutch bell 81 is now freely rotatable relative to the rotor 7. This causes the pump 1 is turned off.

Figure 5 shows a modified embodiment of a pump 1 in longitudinal section, wherein also in this illustration, the pump housing is not shown. The same parts are given the same reference numbers. In this respect, reference is made to the description of the preceding figures.

Visible are a clutch bell 81 as well as the rotor 7 engaging in some regions into the clutch bell 81, the right end 85 of which is designed so that wings can be received here. NEN to realize a vane pump. The opposite left end 87 of the rotor 7 is located inside the clutch bell 81. This in turn receives a wrap 21 of a wrap spring 23. This pump 1 is also provided with a switching device 37, which serves to be able to switch off the pump 1 if necessary. The switching device 37 has a switching body 91, which is also formed in two parts in this embodiment and a first sleeve-shaped part 91a and a second sleeve-shaped part 91b includes. The two parts 91a and 91b are rotatable against each other. They are, as seen in the axial direction, ie in the direction of the axis of rotation 15, fixed.

The two parts 91a and 91b are arranged on the circumferential surface of a switching piston 91c, which here comprises two partial elements 91 'c and 91 "c, which are connected to one another by a screw 93, which is aligned coaxially with the axis of rotation 15.

The switching piston 91 c is at least partially hollow and receives a here designed as a helical spring 101 elastic element. In the embodiment shown here, only the sub-element 91 'c is hollow. The coil spring 101 is supported, on the one hand, on a closure element 97, which seals an interior space 95 of the rotor 7 with respect to the pump space, and on the other hand on the partial element 91 'c. By the coil spring 101, the sub-element 91 'c is urged to the left in the position shown in Figure 5. If a pressure is built up to the left of a switching collar 105 of the partial element 91 'c, the switching piston 91c is urged to the right against the force of the helical spring 101 and displaced in the direction of the axis of rotation 15.

From FIG. 5 it can be seen that the sleeve-shaped part 91a of the switch body 91 extends in the direction of the axis of rotation 15 Recess 67 has. In this engages a first end 65 of the coil spring 21 a.

Figure 6 shows the switch body 91 of the reproduced in Figure 5 pump 1 in a perspective view. The same parts are provided with the same reference numerals, so that reference is made to the description of Figure 5 and the other figures.

The switch body 91 has two sleeve-shaped parts 91a and 91b. Clearly visible is the recess 67, which runs in the direction of the central axis of the switch body 91 and thus the axis of rotation 15. The second part 91b of the switch body is provided with a recess 73 which extends at an angle to the axis of rotation 15. In this one of the control piston 91 'outgoing and radially outwardly directed switching pin 111 engages. If the switching piston 91 'is moved in the direction of the axis of rotation 15 with respect to the axially fixed parts 91a and 91b, the switching pin 111 causes a relative rotation of the sleeve-shaped part 91b relative to the other sleeve-shaped part 91a of the switch body 91, which is held against rotation in the rotor 7. The wrap spring 21, not shown here, of the wrap spring clutch 23 engages with its one end in the first recess 67 of the first part 91a. Its second end engages in a recess 113 of the second sleeve-shaped part 91 b and is also moved in a rotation of the part 91 b relative to the first end in the recess 67 in the circumferential direction of the part 91 b.

Thus, if a pressure is built up on the side 115 of the switching collar 105 facing the observer, then the switching piston 91 'moves along the axis of rotation 15 in FIG. 6 to the top right. Thus, the adjusting pin 111 is displaced in the direction of the axis of rotation 15. Since the switching piston 91 'is rotatably mounted in the rotor 17, the axial movement of the switching piston 91 leads to a of the switching In this way, relative movement of the end of the wrap spring 21 defined in the recess 113 relative to its other end defined in the first recess 67 takes place. If the switching piston 91 'is moved to the right, the wrap spring 21 is tensioned so that the wrap spring clutch 23 is decoupled. This is done by the wrap 21 applies to the peripheral surface of the parts 91a and 91b. In particular, it can be seen that the wrap spring 21 contracts so that its peripheral surface no longer touches the inner surface of the clutch bell 81, which spans the wrap spring 21 with a receiving portion 89, which can thus serve as a coupling region.

If the wrap spring 21 does not touch the receiving portion 89, no frictional forces are transmitted from the clutch bell 81, which is offset by a drive, to the rotor 7, so that the pump 1 is switched off. In this respect, reference is made to the explanations to the preceding figures, in particular to Figure 3.

FIG. 7 shows a further embodiment of a pump 1 in longitudinal section, but without the housing shown in FIG. Identical parts are provided with the same reference numerals, so that in so far as reference is made to the description of the preceding figures.

The pump 1 has a rotor 7, whose right end 85 serves to receive wings, and on the left end of which a sleeve-shaped connecting element is placed, preferably shrunk. In this engages a clutch bell 81, which is acted upon via a clutch 117 by a drive with a torque. The clutch bell 81 is thus in the embodiment shown here at least partially within the Rotor 7 accommodated, so that results in a particularly compact design.

The rotor 7 itself may, as shown here, be formed in two parts and have the connecting element 115, but it is also conceivable to form the rotor 7 and the connecting element 115 as integral components, ie in one piece.

Inside the rotor 7 are a wrap spring clutch 23 with a wrap spring 21, also a switching device 37 with a switch body 91. The switch body 91 has two parts 91a and 91b, also referred to as a pawl body, which can perform a relative rotation to each other. The switching device 37 also has a switching piston 91c, which is displaceable in the direction of the central axis 15 of the pump 1 and thus of the rotor 7. The switching piston 91c has a switching collar 105, which bears sealingly against the inner surface of the interior space 95 in the piston 7. In the functional position shown in Figure 7, the switching piston 91c is located on the right of a wall 119 of the piston 7, which separates the interior 95 of the pump chamber.

The switching device 37 also has a retaining ring 121 which is non-rotatably connected to the rotor 7 and to the first part 91a. It also serves as a stop for the switching piston 91c when it moves from the position shown in Figure 7 to the left.

If, for example, a pressurized fluid is introduced into the region between the wall 119 and the right end face 125 of the control piston 91c via a pressure channel 123, the control piston 91c is displaced to the left from the position shown in FIG. This displacement takes place against the restoring force applied by the wrap spring 21, so that there is no sepa- rate return spring is provided, which was realized by the coil spring 101 of the preceding embodiments.

Figure 8 shows a perspective view of the control piston 91 of the embodiment of the pump 1 shown in Figure 7. The same parts are provided with the same reference numerals, so reference is made to the preceding description.

FIG. 8 shows the two parts 91a and 91b, which are referred to as claw bodies. It is clear that the right part 91a is held in a rotationally fixed manner by the retaining ring 121, here by way of example via at least one claw 127 running parallel to the rotation axis 15 and engaging in the base body of the part 91a. An axial fixation is not given by.

Recognizable here is also the switching piston 91c with the switching collar 105. The retaining ring 121 and / or the first part 91a have a recess 67 into which engages a first end of the wrap spring 21, not shown here. The second part 91b is rotatable relative to the control piston 91c; this is also axially displaceable relative to the second part 91b, which is provided with a second recess 73 into which a second end of the wrap spring 21 engages. If, by means of the control piston 91c, a displacement of the right first part 91a relative to the second part 91b, which can not move to the left in the axial direction in FIG. 7, is effected via the contact surfaces 91 'a and 91' running at an angle to the rotation axis 15. b causes a relative rotation of the part 91b relative to the rotationally fixed part 91a, thus also a relative rotational movement of the two ends of the wrap spring 21 to each other.

Thus, if the control piston 91c is displaced to the left along the rotation axis 15 from the position shown in FIG. 8, the first part 91a is also axially fixed relative to the one in the clutch bell 81. placed second part 91 b along the axis of rotation 15 shifted to the left. In this case, rotation of the first part 91a in the rotor 7 is prevented by the claw 127. The contact surface 91 'a thus rotates the second part 91b within the rotor 7, wherein one end of the wrap spring 21 is entrained by the second recess 73, while the second end of the wrap spring in the retaining ring 121 or in the first part 91a is held against rotation. The wrap spring 21 is formed so that when the first part 91a is displaced leftward in FIG. 8, it is tensioned by the relative rotation of the parts 91a and 91b, so that its peripheral surface is no longer with a receiving portion 89 in the clutch bell shown in FIG 81 is in frictional coupling. As a result, the wrap spring clutch 23 is decoupled: a torque applied by the clutch bell 81 can no longer be introduced into the rotor 7 via the wrap spring 21; the pump 1 is thus switched off.

In order to effect engagement of the wrap spring clutch 23, the pressure between the wall 119 and the shift piston 91c is reduced until finally the wrap spring 21 displaces the shift piston 91c to the right, thus also the first part 91a. Thereby, the lying in the recess 73 end of the wrap spring 21 is rotated relative to the lying in the recess 67 end, so that the wrap spring 21 widens and with its lying in the receiving portion 89 outer circumference with the inner surface of the clutch bell 81 engages: Thus, the wrap spring clutch 23 coupled.

From Figure 7 it is clear that the right end face 125 can be acted upon by a pressurized medium, so that a relatively large area is used to build up a force on the switching piston 91c. The wrap spring 21 is sufficiently biased in the axial direction, so that they in the operation of the Shift piston 91c is not drawn in length, but only twisted.

FIG. 9 shows a further embodiment of a pump 1 in longitudinal section, but without the housing shown in FIG. Identical parts are provided with the same reference numerals, so that in so far as reference is made to the description of the preceding figures.

It comprises a rotor 7, which engages in regions in a clutch bell 81. The rotor 7 is formed at its right end 85 in such a way that wings for realizing the pump 1 can be used. Its left end 87 is hollow and encloses a coil spring 21 a wrap spring clutch 23. In the rotor 7, a switching device 37 is also provided, which cooperates with the wrap spring 21. The switching device 37 comprises a switching body 91, which is formed in two parts and a switching part 91 "includes a and a rotatably connected to this switching element 91" b.

The wrap spring 21 is designed such that it can be accommodated in a first interior 95-1 of the rotor 7. The switching element 91 "b is introduced into the space enclosed by the wrap spring 21. A first end of the wrap spring is non-rotatably connected with the switching element 91" b and a second end is non-rotatably connected to the rotor 7. The switching part 91 "a is rotatably accommodated in the second internal space 95-2 of the rotor 7.

If the wrap spring 21 is firmly seated on the peripheral surface of the switching element 91 "b, it does not come into frictional contact with the inner surface of a receiving section 89 of the clutch bell 81. The wrap spring clutch 23 is decoupled, however, if the wrap spring 21 is widened, it joins frictionally as a coupling Lung portion acting receiving portion 89 of the clutch bell 81, so that a by a drive in the clutch bell 81 introduced torque via the wrap spring 21 to the rotor 7 is transferable.

The actuating device 37 will be explained in more detail with reference to FIG. 10:

FIG. 10 shows the pump 1 in an exploded view. The same parts are provided with the same reference numerals, so reference is made to the preceding explanations.

The parts of the pump 1 are arranged concentrically to an axis of rotation 15. At the bottom left is the clutch bell 81, to the right of which the shift element 91 "b is shown, followed by the wrap spring 21. The rotor 7 has a two-part design 7-1, the wrap spring 21 picks up at least in some areas. It can be seen from FIG. 9 that the sleeve-shaped rotor element 7-1 has a first interior space 95-1 which is separated by a partition wall 129 from a second interior space 95-2 in the rotor 7 In this second inner space 95-2, the switching part 91 "a of the switching element 91 is arranged. It has at least one, here two diametrically opposite vanes 131, 133, which abut with their longitudinal surfaces facing away from the axis of rotation 15 on the inner surface of the sleeve-shaped rotor element 7-1 and separate pressure chambers from one another.

If a pressure is built up on one side of the at least one vane, then it pivots in a first direction about the axis of rotation 15. At a pressure on the opposite side of the wing pivots in the opposite direction. In the embodiment shown here, the rotor 7 also has a rotor section 7-2, which serves to receive wings or other pumping elements. On the side facing the sleeve-shaped rotor element 7-1, at least one, in this case two stop elements 135, 137, originate from the rotor section 7-2, which are arranged at a distance from one another. Their peripheral surfaces are close to the inside of the interior portion 95-2 of the sleeve-shaped rotor element 7-1. In this way, areas are created between the two stop elements 135 and 137, in which the wings 131, 133 can perform said pivoting movement, wherein the inner surfaces of the stop elements 135, 137 limit the movement of the wings 131, 133.

One end of the wrap spring 21 engages in the rotor 7, another end in a recess 139 which is provided on the second part of the Schaltkör- pers 91, namely the switching element 91 "b.

To actuate the wrap spring clutch 23, the switching blades 91 "a are each acted upon by a pressurized medium on one side, so that the at least one vane, in this case the vanes 131 and 133, rotate in one direction via a connecting pin 141 which is non-rotatable is connected to the wings 131, 133, the rotational movement is transmitted to the switching part 91 "b, which in turn is rotatably connected to the connecting pin 141, for example via a two-flat 143th

In the following, the control of the wrap spring 23 is discussed in greater detail: If the at least one wing, here the wings 131, 133, not pressurized, the switch blade 91 "a is rotated by the restoring torque of the wrap 21 to its original position until the wings abut on the stop elements 135, 137. In this functional position, the circumferential surface of the wrap spring 21 lies on the inside of the receiving portion 89 of FIG Clutch bell 81, so that a torque is transmitted to the rotor 7. If the pump 1 is to be switched off, one side of the vanes 131, 133 is subjected to a medium under pressure, for example oil, so that the vanes are rotated in a defined manner relative to the restoring moment of the wrap spring 21. By this rotational movement, the wrap spring 21 can be tensioned so that it rests on the peripheral surface of the switching element 91 "b and its peripheral surface just does not come into frictional contact with the inner surface of the receiving portion 89: Thus, the pump 1 is turned off.

Very well, it is conceivable to turn over the switching function of the wrap spring clutch 23. It is therefore possible that the wrap spring 21 rests on the peripheral surface of the switching element 91 "b in the unpressurized state of the vanes 131, 133 and does not engage the inner surface in the receiving section 89 of the clutch bell 81. Thus, the pump 1 is switched off in a depressurized state If this is to be turned on, one of the sides of the vanes 131, 133 is pressurized, so that the switching part 91 "a is set in rotation. This also leads to a rotation of the switching element 91 "b, so that the wrap spring 21 engages with its outer surface in this design of Schlingenfe- derkupplung 23 with the receiving portion 89 of the clutch bell 81. Thus, the pump 1 is only in operation, if at least one of the vanes 131, 133 is pressurized.

In the exemplary embodiment shown here, there is no need for a separate restoring element in order to pivot the switching leaf 91 "a into its desired functional position. The wrap spring 21 is designed such that it directly builds up this restoring moment. FIG. 11 shows a further embodiment of a pump in longitudinal section. Again, the housing shown in Figure 1 is omitted. It comprises a rotor 7, whose right end 85 is designed so that it can cooperate with at least one wing for conveying a fluid. His left end 87 is at least partially introduced into a clutch bell 81. The rotor 7 is hollow, the interior 95 of which is closed by a closure element 97 to the right, so that it is not in fluid communication with the pump chamber. The interior 95 is divided by a wall 129 into two sections. In the first section 95a, an elastic element formed here as a helical spring 101 is accommodated, in the second section 95b the wrap spring 21 of a wrap spring clutch 23. The spring projects out of the rotor 7 to the left into a receiving section 89 of the clutch bell 81. The inner diameter of the receiving section 89 is matched to the outer diameter of the wrap spring 21, that in a first functional position with its peripheral surface in frictional contact with the inner surface of the receiving portion 89 and in a second functional position in the receiving section 89 is freely rotatable without a frictional torque would be transmitted.

The pump 1 comprises a switching device 37 with a switch body 91. This is in the axial direction, that is in the direction of the axis of rotation 15, movable and is urged by the coil spring 101 in the reproduced in Figure 11 position to the left in a first functional position. The switch body 91 has two parts, namely a first part 91a, which is designed as a piston and has a switching collar 105, which bears sealingly against the inner surface of the first portion 95a of the inner space 95 in the switch body. The first part 91a of the switch body 91 protrudes through the switching bell 81 therethrough. At its end, an abutment 145 designed here as a snap ring is provided. The first part 91a is freely rotatably mounted in a drive element 147, at the free, from the clutch bell 81 projecting end, a drive torque is applied. It is rotatably coupled to the clutch bell 81. By way of example, the free end of the drive element 147 is formed as a square 149. The drive element 147 extends into the interior of the wrap spring 21 and is provided at its inner end with an outer toothing 151, which cooperates with a switching ring 153, which in turn is equipped with teeth. The switching ring 153 is designed so that it is freely rotatable inside the clutch bell 81. He is otherwise rotatably coupled to one end of the wrap 21. The other end is rotatably connected to the rotor 7.

The first part 91a has a switching shoulder 155 against which the drive element 147 abuts. When indicated in Figure 11 functional position of the first part 91a of the switch body 91, the shift shoulder 155 urges the drive member 147 completely to the left, so that its outer teeth 151 is coupled to the switching ring 153. It can be seen that the left end of the drive element 147 is arranged at a distance 157 from the abutment 145.

Figure 12 shows partial elements of the pump 1 in an exploded view, namely the switch body 91, the drive member 147 and the switching ring 153. The same parts are provided with the same reference numerals, so reference is made in so far to the description of the preceding figures.

It becomes clear here that the switch body 91 has a switching collar 105 at its one end, here at its right end, and that the first part 91a of the switch body 91 is characterized by the switching element 91. NEM 149 provided drive element 147 engages. At the end of the first switching part 91a facing away from the switching collar 105, the abutment 145 is provided, which is arranged at a distance from the end face 159 of the drive element 147.

At the opposite end of the end face 159 of the drive member 147, the external toothing 151 is provided, which here has an annular base body 161, from which parallel to the rotation axis 15 here projecting teeth 163 left.

The switching ring 153 in turn has a base 165, from which right-projecting teeth 167 spring. These likewise run parallel to the axis of rotation 15. The teeth 163 of the external teeth 151 and the teeth 167 of the switching ring 153 are formed in width and length such that they are in the functional position according to FIG. 11 and in the relative position of the drive element 147 shown in FIG and switching ring 153 intermesh and thus transmit torque from the drive member 147 on the switching ring 153.

From FIGS. 11 and 12 the following becomes apparent:

If the switching collar 105 is not acted upon by a pressure force built up by a medium, then the coil spring 101 presses the switching element 91 completely to the left, as shown in FIG. 11. Thus, the control collar 105 abuts against the wall 129. By the switching shoulder 155, the drive element 147 is displaced all the way to the left, so that the teeth 163 of the external serration 151 engage in the teeth 167 of the switching ring 153.

If a torque is now exerted on the drive element 147, this is transmitted via the teeth 163 and 167 to the switching ring 153. This is freely rotatable relative to the clutch bell 81. In the starting position, ie without the introduction of a drive torque, the wrap spring 21 of the wrap spring 23 is not on the inner surface in the receiving portion 89 so that it does not transmit torque to the clutch bell 81. If a torque is now introduced into the switching ring 153, the wrap spring 21 transmits this to the rotor 7. If the torque in the drive element 147 is built up very rapidly and / or there is a high counterforce at the right end 85 of the rotor 7, for example because of a cold and viscous medium To promote the pump, the wrap spring 21 is widened upon introduction of a torque in the switching ring 153 so that its peripheral surface engages with the inner surface of the receiving portion 89 and a torque is transmitted to the clutch bell 81. The rotor 7 is rotatably mounted in the clutch bell 81.

If only a small amount of torque is transmitted from the switching ring 153 to the rotor 7, the widening of the wrap spring 21 is prevented, so that its circumferential surface does not bear against the receiving section 89 of the clutch bell 81.

To disengage the wrap spring clutch 23, the switching device 37 is activated. For this purpose, in the first section 95a of the interior 95 in the rotor 7 to the left of the switching collar 105 an overpressure or to the right of the switching collar 105, a negative pressure is built up. As a result, the shift collar 105 is finally displaced to the right against the restoring force of the helical spring 101 and, together with this, the first part 91a. Since this part 91a runs with very little friction in the drive element 147, the first part 91a is displaced to the right, without initially causing a change in the axial position of the drive element 147. That is to say, a first movement of the switching collar 105 does not yet lead to a change the position of the drive member 147 and the teeth 163 relative to the teeth 167th

Since the abutment 145 of the first part 91a is arranged at a distance 157 to the end face 149 of the drive element 147, the switching collar 105 and thus the first part 91a can be displaced to the right until the abutment 145 strikes the drive element 147. Only with a further shift of the shift collar 105 to the right and the drive element 147 is shifted synchronously to the right. Depending on the length of the teeth 163 and 167 measured in the direction of the axis of rotation 15, the drive element 147 together with its external teeth 151 must be displaced to the right over a certain distance until the mechanical coupling, the positive connection, between the external teeth 151 and the switching ring 153 is canceled. In this case, no further torque is transmitted from the drive element 147 via the teeth 163 and 167 to the switching ring 153. As a result, torque no longer acts on the left-hand end of the wrap spring 21 coupled to the switching ring 153 in FIG. 11. The pump 1 is thus disengaged: torque no longer acts on the rotor 7.

If the force acting on the switching collar 105 is reduced, be it the overpressure on the left of the switching collar 105 or the negative pressure on the right of the switching collar 105, then the helical spring 101 can shift the switching body 91, that is to say also the first part 91a to the left. During a first displacement path, the shift shoulder 155 does not touch the end of the drive element 147 opposite the end face 159. Only after a certain pressure change, the shift shoulder 155 abuts on the drive member 147 and moves this due to the pressing force of the coil spring 101 so far to the left until the teeth 163 of the external teeth 151 in the teeth 167th of the switching ring 153 intervene. Only then is a torque transmitted to the wrap spring 21 again. This does not expand at a certain torque and transmits directly introduced into the drive member 147 torque on dne rotor 7. If higher resistance forces act on the rotor 7, the wrap spring 21 is widened until its peripheral surface comes into frictional contact with the inner surface in the Receiving portion 89 of the clutch bell 81st

If the wrap spring clutch 43 is completely engaged, the switch body 91 is in the position shown in FIG. 11, ie, the abutment 45 is arranged at a certain distance 157 from the end face 159 of the drive element 147.

If the wrap spring clutch 23 is now to be disengaged again, the shift collar 105 must first be displaced to the right until the abutment 145 strikes against the end face 159 of the drive element 147. Only then does the decoupling between the teeth 163 and 167 begin.

This results in a switching hysteresis, which is adjustable by the distance 157 between the abutment 145 and the end face 159 of the drive element 47 and by the force of acting as a return spring coil spring 101.

It turns out after all, that the transmission of torque from the drive member 147 on the rotor 7 can be done on the one hand alone on the wrap spring 21, but also by an additional frictional torque between the peripheral surface of the wrap 21 and the inner surface in the receiving portion 89 of the clutch bell 81st With a low torque to be transmitted, this can therefore be transmitted exclusively via the wrap spring 21. If the positive connection between the switching ring 153 and the external teeth 151 of the drive element 147 is interrupted, the wrap spring 21 can relax into its rest position so that it is no longer widened. Thus, there is also no fluid connection, ie no frictional engagement, between the wrap spring 21 and the receiving section 89 of the clutch bell 81. Thus, the pump 1 is switched off.

FIG. 13 shows a part of a pump 1 in longitudinal section. Again, the housing of the pump shown in FIG. 1 is omitted. The same parts are provided with the same reference numerals, so that reference is made to the preceding description.

The pump 1 has a rotor 7, whose right end 85 is designed so that it can interact with at least one wing to promote a fluid. The left end 87 of the rotor 7 projects partially into a clutch bell 81, in which a drive torque is introduced. The rotor 7 is rotatably mounted in the clutch bell 81. The clutch bell 81 is rotated by a drive in rotation and runs continuously with.

The pump 1 has a wrap spring clutch 23 with a wrap spring 21, also a switching device 37. This is located together with the wrap spring 23 in the hollow rotor 7, wherein the wrap spring 21 and the switching device 37 also project into the clutch bell 81, so not completely absorbed by the rotor 7.

The switching device 37 has a switching body 91 with a first formed as a hydraulic piston portion 91a and with a second formed as a friction clutch portion 91b. The second part 91b is provided with a conical outer surface 169 which cooperates with a conical inner surface 171 of the clutch bell 81. The parts 91 a, 91 b, the rotor 7 and the clutch bell 81 are arranged concentrically to the axis of rotation 15.

The first part 91a of the switch body 91 is provided with a switching collar 105, the peripheral surface of which bears tightly against the inner surface of a recess 95 in the rotor 7. The outer diameter of the switching collar 105 is selected such that a region of the first part 91a adjoining the switching collar 105 receives on its circumferential surface the wrap spring 21 in such a way that in its first functional position it does not frictionally contact the inside of the recess 95. The wrap 21 is rotatably connected to the rotor 7. Another end engages in a running in the direction of the axis of rotation 15 recess 67 in the peripheral surface of the first part 91a and is rotatably held here.

In the illustration according to FIG. 13, the switch body 91 designed as a hydraulic piston is in its right-hand functional position, into which it is forced by an elastic element, here by the wrap spring 21. Thus, the conical outer surface 169 of the second part 91b of the switch body 91 is pressed against the conical inner surface 171 of the switching bell 81: a torque introduced into the switching bell 81 is transmitted to the switching body 91 via the friction clutch described here. Since the switch body is non-rotatably connected to one end of the wrap spring 21, the rotor 7 rotates solely on the basis of the force applied by the wrap spring 21 when the torque to be transmitted does not exceed a certain limit. However, when the torque to be transmitted becomes larger, the wrap spring 21 is widened so that its peripheral surface frictionally engages the inner surface of a receiving portion 89 of the clutch bell 81. The torque is thus transmitted not only on the wrap 21 itself but also on the clutch bell 81. From Figure 13 it can be seen that the right end of the wrap spring 21 is further wound, so that the turns have a greater distance from one another. It is designed here as a compression spring 173 in order to improve the restoring forces of the wrap spring 21 and in particular in order to dispense with additional return elements, for example on a coil spring 101, which was mentioned above.

The given between the switch body 91 and the clutch bell 81 friction clutch can be decoupled that the switch body 91 is displaced from the position shown in Figure 13 to the left. As a result, the wrap spring 21 is compressed together with the region formed as a compression spring 173. At the same time, the conical outer surface 169 of the second part 91b of the switch body 91 lifts off from the conical inner surface 171 of the clutch bell 81. The wrap spring 21 can now relax in its rest position, so that there is no frictional engagement between its peripheral surface and the inner surface of the receiving portion 89 of the clutch bell 81: The pump 1 is decoupled from the drive.

FIG. 14 shows the wrap spring 21 greatly enlarged in a perspective view. Top right is the area with the windings further apart, which forms the compression spring 173. By a radially outwardly projecting loop 175, the wrap spring 21 is axially and tangentially fixed in the rotor 7, the düng at a suitable location of the interior 95 enclosing Innenwan- has a corresponding recess.

The compression spring 173 opposite end 177 of the wrap is provided with a still recognizable here radially inwardly projecting lug 179 which engages in the recess 67 shown in Figure 13 and thus causes a coupling with the switching body 91. FIG. 15 shows a side view of a modified exemplary embodiment of a wrap spring 21. It can be seen that here too the last turns of the wrap spring are arranged at a greater distance from one another in order to form a compression spring 73. A wrap spring 21 configured in this way can be used with an exemplary embodiment of a pump 1 which is designed approximately as shown in FIG. In this case, the last turns designed as compression springs 173, whose peripheral surface is adapted to an inner cone, serve as a friction clutch.

In the engaged state, the conical outer surface of the compression spring 173 is located on a conical inner surface of a drive, such as a clutch bell.

If the free end 181 of the conical compression spring 173 is displaced to the left in the direction of the rest of the wrap spring 21, then the cone angle given in the region of the compression spring 173 increases. By a dotted line of the imaginary cone 187 is indicated, on the inner surface of the peripheral surface 183 of the turns of the compression spring 173 lie, if this is not compressed. If the free end 181 of the compression spring 173 is displaced to the left, the result is a conical surface 185, indicated by dashed lines, whose opening angle is greater than that of the cone 187 indicated by dotted lines.

In a compression of the compression spring 173 in the direction of the axis of rotation 15, which coincides with the central axis of the wrap spring 21, the peripheral surface 183 of the compression spring 173 is no longer at a direction indicated by the dotted lines inner cone surface 187: The displacement of the free end 181 toward The remaining part of the wrap spring 21 thus leads to a decoupling of a frictional coupling formed by the peripheral surface 183 of the compression spring 173. The displacement of the free end 181 of the compression spring 173 can be effected on the one hand by forces acting from the right. However, it is also conceivable that an element acts on the free end 181 from the interior of the wrap spring 21 and displaces it to the left for decoupling the friction clutch.

Overall, it can be seen with reference to FIG. 15 that a free end 181 of the wrap spring 21 can be designed as a compression spring 173 whose circumferential surface 183 cooperates with a conical inner surface of a friction clutch. If the measured in the axial direction length of the compression spring 173 shortened by displacement of its free end 181, the frictional engagement between the peripheral surface 183 of the compression spring 173 and an inner cone 187 of a friction clutch is released, so that a torque from a drive is no longer transmitted to a rotor can be.

The wrap spring 21 can therefore also be designed as a coupling.

From the explanations to the pump 1 it can be seen that these can be switched off by means of the wrap spring clutch 23 and the switching device 37 even when a drive torque is applied. The disengagement of the wrap spring clutch 23 takes place with the aid of a pressurized medium. But it is very possible to cause the engagement and disengagement of the pump 1 by means of negative pressure. Thus, if the pump 1 is used to generate a negative pressure, for example in a motor vehicle, then the generated negative pressure can be used to actuate the wrap spring clutch 23 upon reaching a desired negative pressure value and thus to switch off the pump 1. A particularly good switching behavior of the coupling results when, as explained with reference to Figures 11 and 12, a switching behavior with hysteresis is realized. Overall, it turns out that the pump 1 is very simple and compact. It is characterized by a low susceptibility to interference and low production costs.

LIST OF REFERENCE NUMBERS

1 pump

3 housing

5 pump room

7 rotor

9 oil pump

1 1 line

13 hole

15 axis of rotation

17 bearing approach

19 approach

21 wrap

23 wrap spring clutch

25 stub shaft

T1 extension

29 recess

31 snap ring

33 groove

35 groove

37 switching device

39 shift sleeve

41 left end

43 annular bead

45 inner surface

47 front side

49 sealing plate

51 inner edge

53 peripheral surface

55 room

57 bore

59 line

61 coil spring

63 button

65 first end

67 first recess

69 wall

71 second end

73 second recess

77 measuring line

79 Valve device

80 tank

81 clutch bell

83 bearings

85 right end

87 left end

89 receiving section

91 switch body

93 screw

95 interior 97 closure element

99 cavity

101 coil spring

103 inside wall

105 shift collar

107 free space

109 bearings

111 switching pin

113 recess

115 connecting element

117 clutch

119 wall

121 retaining ring

123 pressure channel

125 right end face

127 claw

129 wall

131 wings

133 wings

135 stop element

137 stop element

139 recess

141 connecting pin

143 two-fold

145 abutments

147 drive element

149 square

151 external toothing

153 switching ring

155 shift shoulder

157 distance

159 front side

161 basic body

163 teeth

165 basic body

167 teeth

169 conical outer surface

171 conical inner surface

173 compression spring

175 loop

177 end

179 approach

181 free end

183 peripheral surface

185 cone surface

187 inner cone surface

Claims

claims

1. pump, in particular vane vacuum pump, for motor vehicle brake booster systems, with a rotor (7) via a wrap spring clutch (23) is rotationally driven by a drive, characterized by a switching device (37) which the wrap spring (21) in a first Expands operational position and thus decouples or couples the rotor (7) of the drive, and in a second functional position causes a coupling or decoupling of the rotor (7) with the drive via the wrap spring (21).

2. Pump according to claim 1, characterized in that the switching device (37) comprises a movable switching element having a with a first end of the wrap spring (21) cooperating button (63) which at an angle to the longitudinal axis of the wrap spring (21) is inclined and moves the first end in a first functional position of the switching element in a relaxed or tensioned position.

3. Pump according to claim 1 or 2, characterized in that the switching element has a contact surface on which the second end of the wrap spring (21) rests and parallel to the longitudinal axis (15) of the wrap spring (21).

4. Pump according to one of the preceding claims, characterized in that the switching element is designed as a switching sleeve (39) which is arranged concentrically to the longitudinal axis (15) of the wrap spring (21).

5. Pump according to one of the preceding claims, characterized in that the switching element is hydraulically displaceable.

6. Pump according to one of the preceding claims, characterized in that the switching device (37) has an elastic element which urges the switching element in a functional position, preferably in a second functional position, in which the wrap spring (21) the rotor (7) can couple to the drive.

7. Pump according to one of the preceding claims, characterized in that the switching device (37) is switched in dependence on the pressure in the motor vehicle brake booster system.

8. A pump according to claim 7, characterized in that the drive of the pump (1) is interrupted upon reaching a desired negative pressure in the motor vehicle brake booster system.

9. Pump according to claim 7 or 8, characterized by, an oil supply, which is also interrupted upon interruption of the drive of the rotor (7).

10. Pump according to one of the preceding claims, characterized in that the drive has a rotatably mounted in the rotor (7) stub shaft (25).

11. Pump according to one of the preceding claims, characterized in that the stub shaft (25) in the rotor (7) is secured against axial displacement.

12. Pump according to one of the preceding claims, characterized in that the switching sleeve (39) on the rotor (7) is mounted.

13. Pump according to one of the preceding claims, characterized in that the movement path of the switching sleeve (39) on the rotor (7) is limited.

14. Pump according to one of the preceding claims, characterized in that the switching sleeve (39) with a rotor (7) surrounding the housing (3) forms a pressure chamber.

15. Pump according to one of the preceding claims, characterized in that the switching device (37) comprises a valve, in particular 4/2-way valve for controlling the pressure chamber and the oil supply of the pump (1), which the pressure chamber or the oil supply to an oil supply pump (9) connects, while the oil supply or the pressure chamber depressurized, preferably with a tank (80) of the oil supply pump (9) is connected.

16. Pump according to one of the preceding claims, characterized in that the switching device (37) has a switching body (91).

17. A pump according to claim 16, characterized in that the switching body (91) is formed in two parts.

18. A pump according to claim 16 or 17, characterized in that the parts of the switch body (91) are rotatable against each other.

19. Pump according to one of the preceding claims, characterized in that the switching device (37) at least one with respect to the wrap spring (21) rotatable switch member (91 "a).

20. Pump according to one of the preceding claims, characterized in that a relative to the rotor (7) in the direction of its axis of rotation (15) displaceable drive element (147) is provided.

21. A pump according to claim 20, characterized in that the switching element (91) is coupled to the drive element (147).

22. A pump according to claim 21, characterized in that the coupling has an axial play and thus results in a switching system.

23. Switching element according to one of the preceding claims, characterized in that between the drive (81) and switching element (91) is provided a slip clutch.

24. Pump according to one of the preceding claims, characterized in that the wrap spring (21) as a compression spring (173) is formed.

25. A pump according to claim 24, characterized in that the wrap spring (21) has at least in one area turns with a larger axial distance.

26. A pump according to claim 24 or 25, characterized in that the axial length of the compression spring (173) by force on a free end (181) is variable.

27. Pump according to one of the preceding claims, characterized in that the wrap spring (21) has an area with a conical surface.

28. A pump according to claim 27, characterized in that the region is formed as an outer cone with an opening angle.

29. A pump according to claim 28, characterized in that the opening angle by a displacement of the free end (181) of the compression spring (173) is increased.

30. Pump according to one of the preceding claims 27 to 29, characterized in that the conical portion of the wrap spring (21) is part of a slip clutch.