EP2274519B1 - Controllable coolant pump and method for the control thereof - Google Patents

Description

The invention relates to a controllable coolant pump and a method for controlling this controlled via a pulley coolant pump for internal combustion engines.

In the course of the continuous optimization of internal combustion engines in terms of emission and fuel consumption, it is important to bring the engine after the cold start as quickly as possible to the operating temperature.

This minimizes both the friction losses (as the oil temperature decreases, the viscosity of the engine oil and thus the friction on all oil-lubricated components) reduces the emission values (since the catalysts only become effective after the so-called "light-off temperature", does the period until reaching this temperature be affected significantly the exhaust emissions) and also significantly reduces fuel consumption. Tests in engine development have shown that a very effective means of engine warming is "standing water" or "zero leakage" during the cold start phase.

In this case, in order to bring the exhaust gas temperature as fast as possible to the desired level, during the cold start phase, the cylinder head should not be flowed through by coolant.

In this context, vehicle manufacturers would like leakage flows of less than 0.5 l / h ("zero leakage").

The studies on the fuel consumption of internal combustion engines in motor vehicles have also shown that a consistent thermal management (ie those measures which lead to an energetically and thermomechanically optimal operation of an internal combustion engine) can save about 3% to 5% fuel.

In the prior art, therefore, controllable coolant pumps driven by the crankshaft of the internal combustion engine via pulleys are also described in which the impeller is shiftably driven (for example via a friction pairing) by the pump shaft. With such coolant pumps, a simple two-point control can be realized by means of which the cooling capacity of the coolant pumps can be varied.

In order to initially enable a shorter-term engine warming, the drive of the coolant pump is disengaged during cold start of the engine by means of these designs.

Then, when the engine has reached its operating temperature, the respective friction clutch is activated (with the wear-related functional problems inherent in this type of clutch), i. E. the drive of the coolant pump is turned on.

As a result, large quantities of the still cold coolant are immediately pumped into the engine heated to the operating temperature, so that it inevitably cools down again immediately.

However, the desired benefits of rapid heating of the engine are already partially compensated.

In addition, as a result of the required mass acceleration when switching on again, in particular with larger coolant pumps, very high torques must be overcome, which inevitably result in a high component load.

The Applicant was therefore both in the DE 10 2005 004 315 B4 as well as in the DE 10 2005 062 200 B3 presented two interim proven solutions, which allow an active control of the coolant flow rate to ensure on the one hand by "zero leakage" optimum heating of the engine and on the other hand after the heating of the engine (ie in "continuous operation") to influence the engine temperature so that both the pollutant emission and the friction losses and at the same time the fuel consumption can be significantly reduced in the entire working range of the engine.

In these solutions, in the pump housing a displaceably mounted in the direction of the shaft axis of the pump shaft, annular valve slide with a Ausströmbereich the impeller variable overlapping outer cylinder arranged, which counter to the spring force of return springs either as in the solution according to DE 10 2005 004 315 B4 proposed, electromagnetically, that is, by means of a solenoid arranged in the pump housing, which acts on a rigidly connected to the valve slide armature, or as in the DE 10 2005 062 200 B3 proposed, by means of a pneumatically or hydraulically actuated actuator (which acts hydraulically on the valve slide rigidly arranged, guided in the pump housing piston rods) can be linearly displaced.

This arrangement of a guided, linearly displaceable, the outflow of the impeller variable covering valve spool is a very compact, simple and robust solution, which ensures high reliability and high reliability.

The disadvantage of these solutions, however, (in conjunction with the often very limited installation space for the coolant pump in the engine compartment of motor vehicles) from the mandatory, relatively large "space" either for the solenoid or the hydraulic or pneumatic actuators and their leads.

In the DE 10 2006 034 960 B4 was also a coolant pump with a (analogous to the DE 10 2005 004 315 B4 ) Electromagnetically, or also presented via a gear members by means of a servo motor adjustable valve spool. A major disadvantage of this design is that with this in the DE10 2006 034 960 B4 solution presented one of the "zero leakage" or "zero promotion" can not be realized because the one hand proposed small gap seals still allow leaks and the other hand, described in connection with Figure 4 sealing on "follower" O-rings is not reliable because the high relative speed between the rotating O-ring and the stationary housing inevitably leads to the destruction of the O-ring during operation.

Both require vg. Designs of DE 10 2006 034 960 B4 , as already explained, in turn, on the one hand in the electromagnetic variant for the solenoid, but also on the other hand in the "gearbox" variant for the servomotor a relatively large "space".

Since the electromagnetic variant involves the pump housing in the magnetic circuit, the construction must inevitably for each design and size, i. for each motor application newly revised and adapted structurally.

Another disadvantage of in the DE 10 2006 034 960 B4 proposed direct electromagnetic drive for the valve spool is that this due to space restrictions in conjunction with the / or due to the large initial air gap only conditionally, ie with limited reliability enough force / stroke can muster for safe operation of the valve spool.

In addition, the manufacturing and assembly of the in the DE 10 2005 004 315 B4 , of the DE 10 2005 062 200 B3 as well as in the DE 10 2006 034 960 B4 presented designs very costly and not standardizable, since, as already explained, most of the functional assemblies of the vg. Solutions for Each pump size must be made separately according to different design drawings.

It requires in the DE 10 2005 062 200 B3 presented solution also a factory air-free filling.

Another design of a mechanically driven coolant pump was in the DE 197 09 484 A1 presented. In this solution, a bypass is created by increasing the gap between the open impeller and the housing. This gap can be achieved by means of an electromagnet in the solution in the DE 197 09 484 A1 proposed solution can be varied, with associated driving the electromagnet by means of a pulse width modulated voltage.

This solution, in turn, has significant disadvantages, which include, inter alia, that with in the DE 197 09 484 A1 proposed solution under no circumstances a "zero leakage" ie a zero flow rate can be realized and that even with open bypass, the power consumption of the pump does not decrease significantly (with open bypass decreases the back pressure of the pump - but the flow increases) that with this solution only a poor efficiency can be realized.

The invention is therefore based on the object to develop a controllable coolant pump and a method for controlling this controlled via a pulley coolant pump (with valve spool) for internal combustion engines, which eliminates the aforementioned disadvantages of the prior art, on the one hand by "zero leakage" a ensures optimal warming of the engine and also on the other hand after engine warming the engine temperature in continuous operation is able to influence so accurately that in the entire working range of the engine both the Pollutant emission as well as the friction losses and fuel consumption can be significantly reduced, and also allows even with very limited installation space for the coolant pump in the engine compartment and very low drive power reliable actuation of the valve spool, and even in case of failure of the control further functioning of the coolant pump (Fail-safe) ensures, in addition, by a manufacturing and assembly technology very simple, cost-effective, "standardizable" for different pump sizes optimally occupy the space available in the engine compartment space exploiting design, doing no factory air-free filling requires, also always high reliability and Reliability ensures high efficiency and also allows a simple and cost-effective integration into the engine management.

According to the invention this object is achieved by an apparatus and a method for controlling a driven via a pulley coolant pump for internal combustion engines according to the features of the independent claims of the invention.

DETAILED DESCRIPTION Details and features of the invention emerge from the subclaims and the following description of the solution according to the invention in conjunction with a drawing for the solution according to the invention.

In the FIG. 1 is the inventive variable coolant pump in the side view in section, with the position of the valve spool in its rear end position (ie in the working position "OPEN").

In this design is on a pump housing 1, in a pump bearing 2 driven by a pulley 3 pump shaft 4 with a on a free, flow-side end of this pump shaft 4 rotatably arranged impeller 5 is arranged.

In addition, a pressure-actuated, spring-loaded by a return spring 6 valve spool with a rear wall 7 and the outflow of the impeller 5 variably overlapping outer cylinder 9 is arranged in the pump interior.

In the pump housing 1, a shaft seal 11 is disposed between the impeller 5 and the pump bearing 2 in a seal receptacle 10.

According to the invention, a working housing 12 is arranged on the pump housing 1 and the housing of an electromagnetic actuator 13 is arranged thereon, wherein a working sleeve 14 is arranged in the working housing 12. This is pump shaft side in the working housing 12 adjacent to a pressure chamber 15 which opens via a pressure channel 16 in an annular channel 17, which in one of the seal holder 10 on the impeller side opposite in the pump housing 1 arranged sleeve receptacle 18, rotationally symmetrical to the axis of rotation of the pump shaft 4 is incorporated.

It is advantageous in this context if the housing of the actuator 13 and the working sleeve 14 are made of one piece.

It is also essential to the invention that in the sleeve receptacle 18, an annular piston working sleeve 19 is arranged with a sealing web 20 and a bottom 21 in which the pump shaft 4 rotates freely.

In the outer wall 22 of the annular piston working sleeve 19 21 flow openings 23 are arranged to the annular channel 18 near the bottom.

At the end of the rotary piston working sleeve 19 on the outer side wall 22 of the annular piston working sleeve 19, the inner wall 24 of the annular piston working sleeve 19 is fastened in a force-locking manner to a position securing sleeve 25 with a rigidly arranged wall plate 26.

It is also characteristic that spaced from the bottom 21 of the annular piston working sleeve 19 about the diameter of the flow openings 23, slidably in the annular piston working sleeve 19, a profile sealing ring 27th is arranged. This is on the wing wheel side positively connected to a provided with a web system 28 annular piston 29. On the annular piston 29, the rear wall 7 of the valve slide is arranged in a form-fitting manner in the end region of the wing wheel.

It is advantageous in this context, when the profile sealing ring 27 is knotted into an associated and arranged on the annular piston 29 driving groove. However, it is also advantageous if a sealing ring is arranged between the sealing web 20 and the pump housing 1.

According to the invention, the restoring spring 6 is arranged between the wall plate 26 and the rear wall 7 of the valve slide resting against the annular piston 29.

It is also characteristic that on the outer edge of the wall plate 26, a bypass seal 30 is arranged with an elastomer sealing lip, which prevents a pressure build-up between the wall plate 26 and the rear wall 7 of the valve spool with the resulting bypass leakage at "closed" valve spool.

The inventive arrangement of the bypass seal 30 with the elastomer sealing lip simultaneously causes a tolerance compensation.

The primary seal is ensured between the end face of the outer cylinder 9 and the associated counter surface in the spiral housing.

In cooperation of the two vg. Sealing points with the valve spool, an essential requirement for the solution according to the invention, the function of "zero leakage" (zero promotion) can be optimally realized with minimal power consumption to functionally reliable and reliable to set the coolant flow during the warm-up phase of the engine completely shut down if necessary.

This inventive arrangement of a cylindrical, guided in an annular piston working sleeve 19, spring-loaded annular piston 29 now allows a defined pressure application of the profile seal 27 a reliable, accurate displacement of the valve spool 9 and simultaneously provides a space-optimized, compact, manufacturing and assembly-technically simple, as well as cost-effective and also very robust solution, which always ensures high reliability and reliability.

It is also essential to the invention that a working chamber 31 adjacent to the pressure chamber 15 is arranged in the working sleeve 14, wherein an outlet valve membrane 32 provided with a perforated diaphragm is arranged between the working chamber 31 and the pressure chamber 15.

According to the invention, a working piston 34 arranged on a piston rod 33 is arranged linearly displaceably in the working chamber 31. On this working piston 34, an annular groove 35 with through-holes 36 is arranged on the working space side. The annular groove 35 is adjacent to the working piston 34 also a working piston arranged on the working piston 34, provided with a pinhole intake valve membrane 37 is attached.

It is also characteristic that on the working sleeve 14, the working space 31 opposite, a compression spring system 38 is arranged. According to the invention, a rod seal 39 enclosing the piston rod 33 is arranged between the working chamber 31 and the compression spring system 38. It is essential to the invention that between the working space 31 and the rod seal 39 in the working sleeve 14, an inflow space 40 is arranged in the wall of which inflow openings 41 are arranged, which lead into a arranged between the working housing 12 and the working sleeve 14 annulus 43, with the pump interior. 8 connected via one or more inlet bores 42.

It is also characteristic that a filter element 44 is arranged between the annular space 43 and the inflow openings 41.

According to the invention, a magnet armature 45 is disposed on the end of the piston rod 33 opposite the working piston 34 and is guided linearly displaceably in the actuator 13 in the magnetic field of a magnet coil 46 arranged in a housing of the actuator 13 in a coil receptacle. It is also characteristic that a compression spring 49 is arranged between the pressure spring system 38 arranged on the working sleeve 14 and a spring receptacle 47 arranged on the magnet armature 45, in a spring chamber 48.

It is advantageous if the armature 45 adjacent to the armature 45, an armature stop 50 is preferably arranged with damping element / s in the actuator.

According to the invention, in the housing of the actuator 13, an inlet opening 51 leading into the area of the spring chamber 48 and in the armature 45, in the anchor stop 50 and in the housing of the actuator 13 each adjacent / merging outflow openings 52 are arranged.

Since the rod seal 39 separates the area of the actuator leading to the coolant from an area filled with air ("dry"), the inflow opening 51 and outflow openings 52 allow free gas exchange with the environment, thereby providing a low-friction translational movement of the armature 45 in the area the solenoid 46 is ensured.

In this case, a relatively small diameter of the piston rod again reduces the friction losses on the piston rod in the region of the rod seal 39.

The inventive method for influencing the flow rate of the described in the, in the FIG. 1 illustrated controllable coolant pump is characterized by the fact that by varying the current intensity and / or the duration of the current applied to the solenoid current pulses in the magnetic field 46 acting on the magnet armature 45 force is varied, so that in conjunction with the action of the compression spring 49 on the Magnetic armature 45, the frequency and / or the stroke (the amplitude) of the oscillations of the working piston defined is / are varied so that the working piston 34 by means of the arranged at the opposite end of the piston rod 33 in the magnetic field of the magnetic coil 46 magnet armature 45 repeatedly (periodically), and is placed in defined translational oscillations. This magnetic actuation causes in conjunction with the arrangement according to the invention in many small "part strokes" stocky "pump promotion", which then due to the special arrangement according to the invention has a displacement of the valve spool with its outer cylinder 9 and arranged on these assemblies.

The functional principle according to the invention thus ensures, for the first time with minimal installation space, very low weight, an optimal air gap and an optimized force-stroke ratio by means of the special arrangement according to the invention achieving arbitrarily large actuation forces and working strokes on the valve slide with its profile seal 27, its annular piston 29, its rear wall 7 , its outer cylinder 9 and all arranged on these components according to the invention assemblies.

In the present embodiment, now oscillates the working piston 34, for example, with a frequency of 20 Hz, wherein the respective oscillation amplitude (and thus the stroke of the working piston 34) with the in the FIG. 1 arrangement shown can be varied defined by means of a current applied to the solenoid coil 46 pulse current.

The regulation of the flow rate of the coolant pump according to the invention is effected in that on the one hand working space on the working piston 34, an annular groove 35 is disposed with through holes 36, and that also the working space side, as in FIG. 1 represented, on the working piston 34 is provided with a perforated aperture inlet valve membrane 37 is arranged.

At the same time, on the other hand, between the working space 31 and the pressure chamber 15, an outlet valve membrane 32 is provided which is provided with a pinhole. If now the working piston 34 (as described above) vibrated, so is sucked from the via the inlet bore 42 to the pump interior 8 annular space 43 coolant through the filter element 44 through the inflow openings 41 into the inflow 40 in, and at the same time through the Through holes 36 of the working piston 34 in the working piston arranged on the annular groove 35 and from there Pressed over the provided with a pinhole inlet valve diaphragm 37 into the working space 31, and then introduced from there via the provided with a pinhole exhaust valve membrane 32 into the pressure chamber 15. This introduced into the pressure chamber 15 coolant is passed via the pressure channel 16 in the annular channel 17 and from there via the flow openings (23) in the ring piston working sleeve 19 and there causes a defined pressurization of the profile seal 27 and thus a pressurization of the spring-loaded annular piston 29, which thereby is moved translationally and causes a displacement of the valve spool 9 due to the inventive arrangement.

As a result of the arrangement according to the invention of pinhole diaphragms both in the inlet valve membrane 37 of the working piston 34 and in the outlet valve membrane 32 (ie between the working space 31) and the pressure chamber 15, in addition to the just described "volumetric flow" pumped in accordance with the invention, at the same time a smaller one , but always flowing in the opposite direction according to the invention "leakage volume flow" between the annular piston working sleeve 19 via the working space 31 in the pump interior a.

The superimposed "interplay" of these two volumetric flows according to the invention, which can be varied via the amplitude or the amplitude and / or the frequency of the oscillations of the working piston 34 by means of the solution according to the invention, causes a reliable, path-accurate as a result of the respective built in the pressure chamber 15 working pressure Displacement of the inventively arranged in the annular piston working sleeve 19, spring-loaded annular piston 29 and thus a reliable, precise displacement of the annular piston 29 arranged valve spool 9 which in turn causes an exact variation of the flow rate of the controllable coolant pump according to the invention.

As a result of the arrangement according to the invention thereby arbitrarily large Betätigungskräfte- and strokes can be generated on the annular piston 29 of the valve spool.

Due to the actuating unit according to the invention, it is also possible to provide sufficient for the actuation of the valve spool piston force even with very limited installation space with minimal energy use.

This is also due to the fact that it may take a few seconds in the cooling circuit until the valve spool has approached the position to be taken.

Due to this, the solution of the present invention, which can be easily standardized and manufactured cost-effectively, ensures high pump and motor efficiency with a minimum use of energy (which is less than 5 W).

The "neutral" construction according to the invention makes it possible for the actuator 13 according to the invention to be used as a standardized component in various water pumps.

Thus, a piece-rate effect sets in which the cost-effectiveness and variability in the application for different motor vehicles (engine series) significantly improved on a variety of installation space.

The actuating unit according to the invention, which due to the superposition of a "pumped flow" with a "leakage flow" a space-optimized, compact, manufacturing and assembly technically simple as well as very cost-effective and very robust solution, thus allowing a reliable operation of the valve spool even with very strong limited installation space (for the actuator of the coolant pump).

In case of failure of the regulation, a further functioning of the coolant pump ("fail-safe") is ensured by means of the inventive solution.

In this case, the compression spring 6 moves in conjunction with the "leakage flow" the valve spool in the working position "OPEN".

When spring-loaded "retraction" of the annular piston 29 in the "fail-safe position", the coolant from the annular piston working sleeve 19 via the apertures of the Auslaßventilmembran 32 (ie between the working chamber 31 and the pressure chamber 15) and the orifices of the intake valve diaphragm 37 of the working piston back pressed into the pump interior, wherein the valve spool moves to the working position "OPEN", the "fail-safe position".

In addition, in the solution according to the invention also a factory air-free filling of the actuator of the valve spool can be omitted, since that required for moving the valve spool working fluid, the cooling liquid can be sucked directly from the pump interior.

Another advantage of the solution according to the invention consists in the fact that the filter element 44 does not have to be exchanged during the entire service life, since only very small volume flows (and these always only "down" and then back again) are exchanged via the filter element 44 become.

REFERENCE SYMBOL

1

pump housing

2

pump bearings

3

pulley

4

pump shaft

5

impeller

6

Return spring

7

rear wall

8th

Pump interior

9

outer cylinder

10

seal Housing

11

Shaft seal

12

labor housing

13

actuator

14

working sleeve

15

pressure chamber

16

pressure channel

17

annular channel

18

sleeve receiving

19

Ring piston working sleeve

20

sealing land

21

ground

22

outer wall

23

flow-through

24

inner wall

25

Location securing sleeve

26

shear wall

27

profile seal

28

Steganlage

29

annular piston

30

bypass seal

31

working space

32

Auslassventilmembran

33

piston rod

34

working piston

35

ring groove

36

Through Hole

37

Inlet valve membrane

38

Spring plant

39

rod seal

40

inflow

41

inflow openings

42

inlet bore

43

annulus

44

filter element

45

armature

46

solenoid

47

spring mount

48

spring chamber

49

compression spring

50

armature stop

51

inflow

52

outflow

Claims (7)

1. Controllable coolant pump with a pump housing (1), a pump shaft (4) placed in/on the pump housing (1), on a pump bearing (2) and driven by a belt driven pulley (3), a torque-resistant impeller (5) placed at a free end of this pump shaft (4) in the direction of the current, a pressure controlled shuttle valve, located inside the pump interior (8), controlled by a return spring (6), with a back wall (7) and an exterior cylinder (9) covering the ejection area of the impeller (5) in a variable manner, as well as an annular shaft seal (11) placed into a sealing gland (10) and placed in the pump housing (1) between the impeller (5) and the pump bearing (2), characterized by the fact

   - that a protective housing (12) is located on the housing of an electromagnetic actuator (13) at the pump housing (1), where a protective sleeve (14) is located in the protective housing (12) with an adjacent pressure chamber (15) in the protective housing (12) on the pump shaft side which discharges into an annular duct (17) via a pressure duct (16) which is integrated into a sleeve holder (18), located in one of the sealing glands (10) on the opposite impeller side in the pump housing (1) symmetric to the axis of rotation of the pump shaft (4).

   - that a protective annular piston sleeve (19) with a transverse seal (20) and a base (21), is located in the sleeve holder (18) where a pump shaft (4) freely rotates and where flow holes (23) are located in its outside wall (22) near the base (21) for the annular duct (17) where a position retaining socket (25) is located at the clearly protruding inside wall (24) of the protective annular piston sleeve (19) of the impeller end of the outside wall (22) with a wall plate (26) fixed here so that it forms a positive and interlocking connection.

   - that a profile seal (27) which can move in the protective annular piston sleeve (19) is fitted at a distance approximately corresponding to the diameter of the flow holes (23) from the base (21), which can be slid into the protective annular piston sleeve (19) firmly connected on the impeller side with an annular piston (29) provided with a bridge system (28) whose end area is assigned in a firm or interlocking manner to the back wall (7) of the shuttle valve,

   - that the return spring (6) is positioned between the wall plate (26) and the ring piston (29), or is positioned between the wall plate (26) and the back wall (7) adjacent to the ring piston (29) of the shuttle valve,

   - that a by-pass joint (30) is positioned on the outside wall of the wall plate (26),

   - that a working space (31) is provided in the protective sleeve (14) near the pressure chamber (15), an outlet valve membrane (32) provided with a perforated diaphragm is positioned between the working space (31) and the pressure chamber (15),

   - that a working piston (34) located in the working space (31) and mounted on a piston rod (33) which can slide freely in a linear manner, a radial groove (35) provided with clearance holes (36) is positioned on this working piston (34) at the side of the working area, and also an intake valve membrane (37) and fixed on the working piston (34) at the side of the working area,

   - that a pressure spring unit (38) is located on the protective sleeve (14) on the opposite side of the working space (31),

   - that a rod seal (39) covering the piston rod (33) is positioned between the working space (31) and the pressure spring unit (38),

   - that an admission area (40) is positioned between the working space (31) and the rod seal (39) in the protective sleeve (14), an admission area (40) with intake holes (41) located in its walls which open out into an annular space (43) between the protective housing (12) and the protective sleeve (14) being connected to the pump interior (8) via one or several admission hole(s) (42) where a filter element (44) is located between the annular area (43) and the intake holes (41),

   - that a magnetic armature (45) is positioned on the piston rod (33) opposite the working piston (34) with this being brought into the magnetic field of a moving magnetic coil (46) in the actuator (13) and placed in a coil housing in the actuator (13),

   - that a pressure spring (49) is located between the pressure spring unit (38) located on the protective sleeve (14) and a spring support (47) positioned in a pressure spring (49) on the magnetic armature (45) in the spring compartment (48),

   - that an armature stop (50) is placed in the actuator (13) near the magnetic armature (45),

   - that one/several intake holes (51) leading to the region of the spring compartment (48) is/are placed in the housing of the actuator (13) and also in the magnetic armature (45), in the armature stop (50) and in the housing of the actuator (13) of the outlet holes (52) adjacent to each other.
2. Method for controlling a controllable coolant pump according to claim 1, characterized by the fact that the quantity of liquid carried by coolant pump is controlled in a manner defined by moving the shuttle valve by varying the amplitude and/or the frequency of oscillations in the working piston (34).
3. Controllable coolant pump according to claim 1, characterized by the fact that the housing of the actuator (13) and the protective sleeve (14) are made in one piece.
4. Controllable coolant pump according to claim 1, characterized by the fact that the profile seal (27) is integrated into a driving slot positioned and assigned to the annular piston (29).
5. Controllable coolant pump according to claim 1, characterized by the fact that a sealing ring is positioned between the transverse seal (20) and the pump housing (1).
6. Controllable coolant pump according to claim 1, characterized by the fact that there is/are one/several intake holes (51) in the housing of the actuator (13) supplying the area of the spring compartment (48) and also in the area of the magnetic armature (45), the armature stop (50) and the housing of the actuator (13) are assigned to the outlet holes (52) adjacent to each other.
7. Method for controlling a controllable coolant pump according to claim 2, characterized by the fact that alteration of the strength of current and/or in the duration of the electrical pulse applied to the magnetic coil (46) with the force acting on the magnetic coil (46) on the magnetic armature (45), associated with the action of the pressure spring (49) on the magnetic armature (45) is varied in such a way that the frequency or the rise (amplitude) of the oscillations of the working piston (34) is shifted (in a repetative/periodic) manner so that the working piston (34) is set into oscillating movement by using the magnetic armature (45) located in the magnetic field of the magnetic coil (46) placed at the opposite end of the piston rod (33) and is set into translatory oscillation.

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