Device and method for the defined longitudinal shifting of an adjusting device, which rotates along in a drive shaft

The invention relates to a device and method for the defined longitudinal shifting of an adjusting device which rotates along in a drive shaft, along the center axis of the drive shaft. The solution according to the invention is characterized in that a working chamber (12) is arranged at the opposite end of the drive shaft (1), into which working chamber a passage hole (7) arranged in the drive shaft (1) opens, wherein a working piston (13) that operatively connects to the working chamber (12) is arranged in such a way that, in the event of a pressure build-up in the working chamber (12), the adjusting device (2) is variably moved against the spring force of a restoring spring (10) by means of a radial piston pump according to the invention that is arranged on the drive shaft (1).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of PCT/DE2012/000172 filed on Feb. 22, 2012, which claims priority under 35 U.S.C. §119 of German Application No. 10 2011 012 827.1 filed on Mar. 2, 2011, the disclosures of which are incorporated by reference. The international application under PCT article 21(2) was not published in English.

The invention relates to an apparatus and a method for defined longitudinal displacement of an adjustment apparatus that rotates along with and within a drive shaft, along the center axis of the work shaft.

In the state of the art, apparatuses for defined longitudinal displacement of adjustment apparatuses that rotate along with and within the drive shaft, i.e. along the center axis of the drive shaft, are previously described in connection with the regulation of liquid or gaseous volume streams in pumps or compressors.

For example, DE 2110776 A1 describes a flow work machine having regulatable impeller cross-sections, in which machine an adjustment spindle that rotates along, driven by way of the blade wheel, is disposed within the drive shaft, which spindle can be longitudinally displaced in the drive shaft by means of a piston drive provided with a regulator.

This solution has the disadvantages that it requires a very large construction space, is material-intensive and cost-intensive, furthermore has a structure that is very susceptible to failure, does not switch to maximal power automatically if the regulation fails, and furthermore carries a high risk with regard to the aspect of work safety.

In other designs, the adjustment apparatus and the work spindle are disposed not within one another in the axial direction, as described above, but rather disposed to lie flush with and opposite one another.

Such a design is previously described in DE 37 32 038 C2. In this design, the adjustment apparatus is once again carried along by the drive shaft, by way of the blade wheel. In this solution, the adjustment apparatus can be displaced in defined manner, by means of a partial vacuum, by way of a separate activation element disposed on the pump housing, lying opposite to the drive means of the drive shaft, a V-belt pulley.

Failure of the regulation brings about the result that in this solution, a switch to maximal pump power takes place automatically, by means of a reset spring.

However, this design also requires a very large construction space in connection with the pressurized lines, the required pressure regulator, etc., and is therefore also material-intensive and cost-intensive.

In other solutions, adjustment apparatuses in the form of pressure-spring-impacted thermostats/wax elements were integrated on the drive shaft, with significantly less effort and a smaller construction volume.

Such solutions are previously described, for example, in U.S. Pat. No. 4,828,455 or also in DE 199 01 123 A1.

The significant disadvantage of these solutions, however, consists in that they react too slowly for active regulation of the conveyed coolant amount, and by no means are able to influence the engine temperature in such a way, after it has warmed up (i.e. in “continuous operation”), that not only the pollutant emissions but also the friction losses and also the fuel consumption could be clearly reduced in the entire work range of the engine.

For this reason, it was proposed, for example in DE 10 2008 046 424 A1, to use electromagnetically activated adjustment apparatuses, i.e. to displace rotating components using a magnetic coil disposed in the pump housing.

In this solution, a magnet armature is rigidly disposed in the magnetic field of a magnetic coil integrated into the pump housing, at the end of the adjustment apparatus that lies opposite the adjustment element, by means of which the adjustment apparatus guided in the drive shaft can be linearly displaced, under the effect of the electromagnetic field of the magnetic coil.

The installation of such electromagnetically activated adjustment elements, for example in the vicinity of the turbocharger, necessarily requires cooling of the magnetic coil (and thereby a relatively large “construction space”), because the magnetic coil would be destroyed at temperatures starting from 120° C.

This relatively large “construction space” that is in turn necessarily required, also for the magnetic coil disposed in a pump housing, according to DE 10 2008 046 424 A1, is diametrically opposed to the very limited “installation space” that is available in the engine compartment.

Furthermore, a disadvantage of this solution is that production and installation are very cost-intensive, because the functional modules cannot be uniformly produced for multiple construction sizes, i.e. standardized, and therefore have to be produced separately for every pump housing size.

The invention is therefore based on the task of developing an apparatus and a method for defined longitudinal displacement of an adjustment apparatus that rotates along with and within a drive shaft, along the shaft center axis of the drive shaft, particularly in connection with the regulation of liquid or gaseous volume streams in pumps or compressors, which eliminates the aforementioned disadvantages of the state of the art, and, in this connection, guarantees active and reliable regulation of the longitudinal displacement over the entire range of the speed of rotation and temperature, with very little work effort, which is furthermore suitable even for high-rpm applications and can be used even under disadvantageous general thermal conditions, such as in the vicinity of a turbocharger, for example, while having a small and compact structure, working robustly, and optimally utilizing the existing construction space, furthermore can be produced, at the same time, in simple and cost-advantageous manner, in terms of production and assembly technology, always guarantees a high level of operational safety and reliability, and is suitable as a unit even for different pump sizes, i.e. can be produced in “standardized” manner, and, at the same time, can be integrated into any desired regulation circuits, in simple and cost-advantageous manner.

According to the invention, this task is accomplished by means of an apparatus and a method for defined longitudinal displacement of an adjustment apparatus that rotates along with and within a drive shaft, along the center axis of the work shaft, in accordance with the characteristics of the independent claims of the invention.

This solution according to the invention, for defined longitudinal displacement of an adjustment apparatus2that rotates along with and within a drive shaft1, along the center axis of the work shaft, shown inFIG. 1in the form of a schematic representation of the principle of action of the invention, in an axial section, and inFIG. 2in the form of one of the possible design embodiments of the solution according to the invention, in section, in a side view, having a drive shaft1mounted in/on a housing3, in a bearing4, driven by a drive element5, projecting into a work space6filled with pressurized medium, having a through-hole7that accommodates the adjustment apparatus2, is characterized in that a spring chamber8is disposed on the drive-side end, in the through-hole7, and that a spring stop9is disposed on the drive-side end of the adjustment apparatus2, in such a manner that the adjustment apparatus2is always brought back into a defined starting position after every axial displacement, by means of a reset spring10that is disposed in the spring chamber8. It is essential to the invention, in this regard, that a work chamber12is disposed at the end of the drive shaft1that lies opposite the drive element5, into which chamber the through-hole7opens, whereby a ring space11is disposed between the through-hole7and the adjustment apparatus2disposed in this bore, whereby a work piston13that enters into an active connection with the work chamber12is disposed at the end of the adjustment apparatus2that lies opposite the spring stop9, in such a manner that when pressure builds up in the work chamber12, the adjustment apparatus2can be variably displaced in the through-hole7, counter to the spring force of the reset spring10.

It is characteristic, in this connection, that a pump piston18having a piston pass-through bore19, which bore opens into a pressure channel17disposed in the housing3, is disposed in the housing3, so as to pivot.

A significant characteristic of the invention, in this connection, consists in that an eccentric bushing21is disposed in the region of the pump piston18, on the drive shaft1, so as to rotate with it, in which bushing a suction kidney22connected with the work space6, on the one hand, and a pressure kidney23that lies opposite on the circumference of the eccentric bushing21, on the other hand, are disposed, whereby the pressure kidney23has a transfer bore24disposed in the eccentric bushing21, which bore opens into a further transfer bore24disposed adjacent to the drive shaft1, and thereby connects the pressure kidney23directly with the ring space11.

It is also essential to the invention, in this connection, that a cylinder ring25having a piston bore26for the pump piston18is disposed on the outer mantle of the eccentric bushing21, so as to rotate, in such a manner that when the eccentric bushing21is rotating, the pump piston18“works” in the piston bore26of the cylinder ring25, i.e. moves vertically up and down in oscillating manner, and pumps medium contained in the work space6into the pressure kidney23, by way of the suction kidney22, when the solenoid valve29is closed, which medium is conveyed from there into the work chamber12, by way of the transfer bores24and the ring space11.

In this connection, it is characteristic that a valve seat27is disposed in the housing3, into which seat the pressure channel17opens, on the one hand, and a return line28connected with the work space6opens, on the other hand, whereby a solenoid valve29is disposed in the valve seat27, between the pressure channel17and the return line28.

When the drive shaft1is rotating and the solenoid valve29is closed, the pump piston18, which moves vertically up and down in the piston bore26of the cylinder ring25, in oscillating manner, according to the invention, causes medium contained in the work space6to be pumped into the pressure kidney23, by way of the suction kidney22, and from there to be conveyed into the work chamber12by way of the transfer bores24and the ring space11.

It is also advantageous, in this connection, that piston rings32are disposed on the outside circumference of the region of the pump piston18that is displaceably mounted in the piston bore26of the cylinder ring25, which rings guarantee a high degree of effectiveness of the arrangement according to the invention, with little production and assembly effort.

InFIG. 2, one of the possible design embodiments of the solution according to the invention is now shown, in the design of a coolant pump for motor vehicles, having a setting slide35that can be displaced by way of the adjustment apparatus2, which slide serves for varying the “effective” blade width of the vane wheel.

The drive shaft1, which is mounted in the housing3in a bearing4, driven by a drive element5, projecting into a work space6filled with pressurized medium, in which shaft a through-hole7that accommodates the adjustment apparatus2is disposed, is particularly characterized in that a pivot cylinder15provided with a dead-end bore14that is closed off toward the work space6is disposed in the housing3on the work space side, the open bore end16of which cylinder opens into a pressure channel17, whereby a pump piston18having a piston pass-through bore19is disposed on the pivot cylinder15, so as to rotate, and this piston pass-through bore19opens into the dead-end bore14of the pivot cylinder15by way of a through-passage bore20disposed in the pivot cylinder15in the region of the piston pass-through bore19.

It is also characteristic, in this connection, that the transfer region into the suction kidney22that is open at a side wall is configured as a ring channel30, adjacent to which, on the outside, i.e. toward the work space6, a ring-shaped gap filter31is disposed, so that in this region, passage of cooling medium from the pump interior14into the ring channel30is possible, whereby penetration of undesirable particle sizes of chips and sand grains is prevented by means of the setting of the filter gap of the ring-shaped gap filter31.

If now, in this concrete embodiment according to the invention, as shown inFIG. 2, the drive shaft1is put into rotational movement by way of the drive element5, a belt pulley, then at the same time, the eccentric bushing21disposed on the drive shaft1so as to rotate with it, which bushing is provided with a suction kidney22that is open toward the side wall on the vane wheel side, on the one hand, and with a pressure kidney23that is open toward the passage bore7in the drive shaft1, on the other hand, is put into rotational movement.

In this connection, the cylinder ring25that is mounted on the outer mantle of this eccentric bushing21, so as to rotate, is put into lifting movements with the piston bore26disposed in it.

The work piston13disposed in the piston bore26, with its piston pass-through bore19disposed in the work piston13, easily oscillates around the pivot cylinder15provided with the dead-end bore14, when the eccentric bushing21is rotating; the piston pass-through bore19opens into the dead-end bore14by way of a through-passage bore20disposed in the pivot cylinder15.

The vane wheel bushing of the vane wheel of the conveying pump33, shown inFIG. 2, disposed on the drive shaft1, by means of being disposed in the vane wheel as an insert, lies against the eccentric bushing21in the embodiment shown in thisFIG. 2, whereby the vane wheel forms a gap filter31with the adjacent face side of the cylinder ring25, adjacent to which the ring channel30is disposed on the eccentric bushing side.

The (open side wall of the) suction kidney22is disposed laterally adjacent to this ring channel30.

As a result, continuous passage of medium, by way of the ring-shaped gap filter31, from the work space6into the ring channel30, and, by way of the latter, into the suction kidney22, which is open on the side wall side in the region of the ring channel30, is guaranteed.

As is shown inFIGS. 1 and 2, a conveying pressure is built up in connection with the conveying pump33, in the work space6, and, for example, at the same time, also in a conveying circuit34.

The rotating drive shaft1according to the invention now also brings about defined “conveying” of the medium, according to the invention, from the work space6, by way of the suction kidney22, into the piston bore26, and from there, by way of the piston pass-through bore19, and in an embodiment as shown inFIG. 2, further by way of a through-passage bore20and a dead-end bore14of a pivot cylinder15, into the pressure channel17regulated by the solenoid valve19.

When the solenoid valve29is open, the medium conveyed in this manner flows back into the work space, by way of the solenoid valve29and a return line28, and the setting slide35shown inFIG. 2lies against the vane wheel of the conveying pump33in its rearmost end location position.

In this connection, the gap dimensions between the housing3and the setting slide35are dimensioned in such a manner that an inflow of conveying medium from the work space6into the ring channel30is guaranteed even in the rearmost end position.

When the solenoid valve29is closed, a “dynamic pressure” is built up from the piston bore26all the way to the pressure channel17, which brings about the result that medium pumped into the piston bore26by the suction kidney22is pressed into the pressure kidney23, and from there gets into the ring space11by way of the transfer bores24, enters into the work chamber12by way of this space, and there brings about a displacement of the work piston13, counter to the spring force of the reset spring10, and, in this connection, as shown inFIG. 2, activates a setting slide35, for example.

The stroke of the pump piston18in the piston bore26of the cylinder ring25amounts to approximately 1 mm to 2 mm per revolution in the present exemplary embodiment. As a result of the arrangement according to the invention, even very small conveying amounts are already sufficient for precise displacement of the work piston13, which is rigidly disposed on the spring-loaded adjustment apparatus2.

The method according to the invention for defined longitudinal displacement of an adjustment apparatus2that rotates along with and within a drive shaft1, by means of the apparatus described above, is characterized, in this connection, in that the adjustment apparatus2can be displaced in the longitudinal direction in defined manner, by means of a solenoid valve29by varying the pressure in the pressure channel17.

When the solenoid valve29is “open,” i.e. without current in the present exemplary embodiment, the piston pump according to the invention conveys medium, here coolant, back into the work space6by way of the return line28of the solenoid valve29, in “pressure-free” manner, as has already been explained.

If now the return flow of the medium conveyed by the piston pump according to the invention into the return line28and thereby back into the work space6is throttled or actually completely prevented by means of the solenoid valve29, then the cooling medium conveyed by the arrangement according to the invention is pressed into the work chamber12by way of the ring space11, and thereby the pressure in the ring space11and also in the work chamber12is first increased, in step-free manner.

In this connection, the medium pressed into the work chamber12in this manner brings about a defined pressure application to the work piston13shown inFIG. 2of the adjustment apparatus2spring-loaded by the reset spring10, which pressure can be adjusted (by way of the solenoid valve29), and thereby a defined longitudinal displacement of the adjustment apparatus2that rotates along with and within the drive shaft1.

This defined application of pressure to the cross-sectional surface area of the work piston13by way of the solenoid valve29now makes precise translational displacement of an adjustment apparatus2that rotates along with and within the drive shaft1possible, as shown in the exemplary embodiment according toFIG. 2, for example, and thereby the adjustment of a displaceable setting slide35that is disposed on this rotating adjustment apparatus2and rotates with it, for variation of the “effective” blade width of a vane wheel of a conveying pump33.

In this connection, the arrangement according to the invention guarantees active and reliable regulation of the longitudinal displacement of the adjustment device2over the entire range of speed of rotation and temperature, in all the embodiments presented, at very low drive power.

Because of the forced operation by means of the eccentric drive, according to the invention, of the pump according to the invention, the present solution is suitable even for applications at high speeds of rotation.

The solution according to the invention has a very small construction and optimally utilizes the available construction space, is very compact and works very robustly and reliably.

In this connection, the present solution can be produced in simple and cost-advantageous manner, in terms of production and assembly technology, and always guarantees great operational reliability.

Even under very disadvantageous thermal general conditions, such as, for example, in the vicinity of a turbocharger in a motor vehicle, and, at the same time, with greatly limited installation space, the solution according to the invention guarantees optimal cooling with minimized construction volume and great reliability, as a result of the provision of a solenoid valve29that is simultaneously cooled by the conveying medium.

Even in the event of failure of the regulation mechanism, “fail-safe” operation can be implemented as described below, by means of the solution according to the invention.

In the non-powered state, the solenoid valve29opens, the pressure in the pressure channel17and in the work chamber12drops, and spring-loaded “movement back” to the rearmost work position of the regulating slide35takes place, in the embodiment of the invention as shown inFIG. 2, for example into “emergency operation,” i.e. a “fail-safe” position.

When the adjustment apparatus2“moves back,” the medium contained in the work chamber12, and also the medium being pumped by the arrangement according to the invention at this time, is passed into the return line28by way of the pressure channel17and the solenoid valve29(which is open when the adjustment apparatus2moves back), and from there back into the work space6.

When the adjustment apparatus2is “held” in an intermediate position, the flow through the solenoid valve29, for example, is released just to such a point that only the medium being pumped by the arrangement according to the invention flows out of the pressure channel17into the return line28, by way of the solenoid valve29, and from there back into the work space6.

The solution according to the invention is also particularly characterized by its very short construction, in terms of its longitudinal expanse, which is able to optimally utilize even very small construction spaces.

Furthermore, the solution according to the invention can be “standardized” as a unit and therefore can be used even for different pump sizes.

In this connection, the solution according to the invention can also be integrated into different regulation circuits, in simple and cost-advantageous manner.

REFERENCE SYMBOL LISTING