ES2228394T3 - HYDRAULIC DEVICE FOR TRANSMITTING THE MOVEMENT OF AN ACTUATOR. - Google Patents

Abstract

Device for transmitting the movement of an actuator (8) to an adjustment member (3) with a transmission element that generates an active connection between the actuator (8) and the adjustment member (3) and which determines a hydraulic chamber ( 22) and an accumulator chamber (24), which are filled with a hydraulic liquid and which are joined together by at least one throttle gap (36, 37), the transmission element having a first and a second piston element ( 21, 23; 121), the first piston element (21; 121) being fixedly connected with the actuator (8) and the second piston element (23) fixedly with the adjusting member (3), being configured between the first piston element (21; 121) and the second piston element (23) the hydraulic chamber (22) and including the accumulator chamber (24) a zone of accumulator chamber (242, 243) loaded with pressure, which is delimited by bellows metallic, characterized in that the metal bellows icos form a system of induced bellows (25, 26, 125) and are prestressed by means of a spring element such that the area of the accumulator chamber is loaded with pressure and whose pressure is approximately constant.

Description

Hydraulic device to transmit the actuator movement.

The invention relates to a device hydraulic to transmit the movement of an actuator to an organ adjustment according to the general concept of claim 1, in Particular for use in a fluid dispenser. A device like this, referred to in the following transmission element, It is known from DE 197 08 304 A1 and US 4858439.

In the technique of motor vehicles, increasingly use accumulator injection systems, in the It works with very high injection pressures. In these known injection systems for example under the name "Common-Rail" systems fuel is applied under high pressure in the injection valves arranged in the combustion machine cylinders. The injection process in The cylinders are activated by opening and closing the valves injection, the injection valves being controlled by actuators, which operate according to the electromagnetic principle and, to achieve high maneuver speeds, also according to the piezoelectric, electrostrictive or magnetostrictive principle. The injection valve actuators then act, given the case by inserting a servo valve, a valve needle in the injection valve

To a fuel injection valve of In particular, the following requirements are formulated:

The valve needle must be arranged in the injection valve, either without load, or loaded with a force Pressure dependent. If there is a pressure of increased fuel in the valve needle, must be guaranteed, to ensure sufficient tightness with a pressure of increased fuel, let the valve needle always press fixedly on the valve seat.

In addition, the injection valve must be insensitive to thermal elongations or induced by Pressure. Nor should the functionality of the valve be affected. injection due to fatigue effects, activated for example by Actuator aging processes. To avoid modifications in the length of the injection valve caused by effects thermal, pressure or fatigue, are usually manufactured the valve needles and the other valve elements of injection of special steels, which are nonetheless very expensive. In addition, it is also necessary when such steels are used expensive specials provide for a sufficient distance between different elements, to be able to absorb possible extensions between the elements This necessary safety distance of 3 \ mum to 5 \ mum is nevertheless lost as a useful run of the actuator, which, especially when using a piezoactuator which only brings a small career, can lead to problems Open the valve needle.

In order not to have to anticipate any interstitium between the different parts of the injection valve, is proposed in the DE 197 08 304 A1 a hydraulic transmission element, which transmits actuator deflection in the injection valve to a column of actuating the servo valve or to a guide shaft of the valve needle The hydraulic transmission element is configured essentially with cylindrical shape and presents a hydraulic chamber, which is limited by a flexible membrane. The drive column of the the servo valve or the guide shaft of the valve needle. From the hydraulic chamber, a joint hole with the effect of throttling leads to an accumulator chamber, provided in the inside the transmission element and that is closed by a prestressed spring plate. On the spring plate is arranged in the hydraulic chamber a rigid cover plate, which is supports on the actuator of the injection valve. The camera hydraulic and the accumulator chamber are filled with a medium hydraulic.

In idle state it is transmitted through the union hole the pressure of the hydraulic medium that reigns in the accumulator chamber to the hydraulic chamber, bringing the membrane flexible always rests on the drive column of the servo valve or on the guide shaft of the valve needle, even when due to thermal effects or to processes of aging results displacements in the disposition of different components in the fuel injection valve. When the actuator is actuated, the deflection of this actuator through the transmission element on the actuator column of the servo valve or the shaft guide valve needle. The junction hole between the chamber hydraulic and the accumulator chamber is then designed in such so that, because the command times are in the range of milliseconds, essentially no amount can flow of hydraulic means out of the hydraulic chamber towards the accumulator chamber

However, the known transmission element by DE 197 08 304 A1 is characterized by a structure complicated In addition, with this known transmission element is difficult to ensure a temperature compensation along The entire working range of the fuel injection valve about -40ºC to + 150ºC. In this wide range of temperatures you can reach a variation in the volume of the hydraulic medium used in the transmission element of up to 20%. But a variation of such a large volume can only be mastered with much difficulty in the structure provided for in DE 197 08 304 A1.

It is the task of the present invention to put provision a hydraulic device without play to transmit the movement of an actuator to an adjustment body, characterized for high reliability for high permanent loads and strong temperature swings.

This task is solved by a device. according to claim 1. Other advantageous improvements are indicated in the secondary claims.

The device corresponding to the invention is characterized by a transmission element that has a first piston element, fixedly connected with an actuator, and a second piston element, fixedly connected with an adjustment member, being configured between the first piston element and the second element of piston a hydraulic chamber, and including an accumulator chamber joined with the hydraulic chamber by means of an interstitium of strangulation, an area loaded with pressure, the limits of whose Zone are set elastically. This structure guarantees reliably automatic compensation of large variations distance between the actuator and the adjustment body, which can come caused by thermal effects of pressure or fatigue. In addition, through the elastic design of a chamber area accumulator is ensured that the transmission element retains its functionality over a wide range of temperatures, in particular the entire working range of an injection valve approx. -40 ° C to 150 ° C. The transmission element corresponding to the invention can also be applied both in a fuel injection valve that opens inwards as in one that opens out. In addition, the element of transmission by a very compact constructive form, a performance of very high hydromechanical transmission and properties of outstanding dynamic transmission, since only one is needed Very small hydraulic chamber between the first and second element piston

According to the invention, the elastic zone of the chamber accumulator is delimited by a system of wavy bellows, preferably composed of metal bellows units. Such Metal bellows units are designed radially very rigid, but very soft in axial direction and can thus absorb reliably variations of hydraulic fluid volume content in the transmission element.

According to another preferred constructive form, prepress the actuator by means of a spring element, which is attached fixedly with the first piston element of the element of transmission. Through this improvement you can size a replacement spring, which restores the adjustment body to its position starting after the end of the actuator control process, such that be very small, since the operation of the replacement spring it is supported by the actuator retraction movement, which acts through the transmission element on the adjustment member.

According to another preferred constructive form, by choosing the right size relationships between effective surfaces for the pressure of the first piston element and from the second piston element, a transformation of the actuator movement stroke over the adjustment body Thus it is achieved that also when using a piezoelement as an actuator a sufficient stroke is generated to actuate the adjustment body.

The invention is described below in detail based on the schemes. It shows in

fig. 1 a fuel injection valve that opens out with a hydraulic transmission element corresponding to the invention in a first form constructive

fig. 2 a fuel injection valve that opens inwards, with a hydraulic transmission element corresponding to the invention in a first constructive form; Y

fig. 3 a fuel injection valve that opens out with a hydraulic transmission element corresponding to the invention in a second form constructive

The fuel injection valve shown in figure 1, which opens out in a combustion chamber of a combustion machine, it works with fuel that It is under high pressure. In this injection valve is housed in the upper part of a housing 1 a unit of drive, which features an actuator as an essential part 8 piezoelectric multilayer in low voltage technique. This actuator piezoelectric multilayer 8 is surrounded by a tubular spring 9, which is welded between a header plate 10 and a bottom plate 11, the tubular spring 9 being prestressed in such a way that the multi-layer piezoelectric actuator 8 is under a voltage mechanical prior The housing 1 is also connected with a plate bottom 11 of the drive unit as rigidly possible, preferably by means of a weld bead 12.

The multilayer piezoelectric actuator 8 acts, when he receives an electrical order through his lines of inlet 19, by means of a hydraulic transmission element on the rear end of a valve needle 3. The valve needle 3 it is arranged in the front part of the housing 1 of the valve injection into an inner passage hole 30 and seal in the state of resting, by means of a valve plate 4 arranged at the end front of the valve needle 3, a valve seat 2 in the housing 1. The starting state of closure in the injection valve is secured in this regard by a nozzle spring 5 prestressed, which is connected to the valve needle 3 by means of a clamping ring 6 and pressing the valve plate 4 on the valve seat 2. When the piezoelectric multilayer actuator 8 receives a command signal, the deflection transmitted by the transmission element 3 to the rear end of the needle of the valve 3, lift the valve plate 4 from the seat of the valve 2, bringing the fuel into a chamber of fuel 13 in the housing 1 through an inlet pipe of fuel 7, can be injected through the needle of the 3 valve in the fuel chamber of the machine combustion.

Since the fuel is under a very high pressure in the fuel chamber 13 in the housing 1, this area must remain reliably waterproofed against to the other areas in the housing 1 of the injection valve, in particular facing the drive zone. For the hermetic waterproofing and for very smooth axial conduction of the valve needle 3 from the fuel chamber 13 towards the area in which the transmission element and the unit are housed drive, serves a metal bellows 15. With the camera fuel 13 limits an annular shaped projection 14, which penetrates in the inner hole 30. The valve needle 3 is housed also a connecting piece 16 with an annular shape. Between the piece of connection 16 of the valve needle 3 and the annular projection 14 which goes around in the housing 1, the metal bellows 15 is welded, running parallel to the needle of the valve 3, and serving for the hermetic sealing of the fuel chamber 13 in front of the other housing areas where the drive unit and transmission element. Besides, the Valve needle 3 is secured by metal bellows 15 in front of the turn. This can be especially advantageous when a stopper that is housed in the fuel injection valve limit the stroke for the valve needle 3.

The use of the metal bellows 15 for Needle conduction allows perfect waterproofing, durable and reliable high pressure zone in the valve injection compared to other areas. The metal bellows 15 supports, as the calculations and tests have shown, and despite the small wall thickness of for example 50 µm up to 500 um, and due to its very high radial stiffness, very high pressures high, without suffering any irreversible deformation. Bellows metallic 15 may also be designed so that, by means of a sufficient amount of undulations, high axial flexibility, that is, a low elastic coefficient in the direction of movement of the valve needle 3, for not affect the deflection of the valve needle 3 and to maintain as small as possible the forces generated by the length variations due to the temperature of the passage zone of the needle in the needle of the valve 3. Also, by means of the use of the metal bellows 15 can be avoided with great Reliability a fuel leak in the needle guide.

The passage area of the needle formed by the protrusion 14 with annular shape, metal bellows 15 and the piece of connection 16, can also be perfected in such a way that the forces due to pressure acting on the valve needle 3 compensate each other, so that the valve needle 3 is, in as a whole, kept stress free. This allows to design the injection valve in such a way that behavior is possible in the connection practically independent of the pressure of the fuel, since the opening and closing forces only come then determined by the piezoelectric multilayer actuator 8 and the force of the prestressed nozzle spring 5.

In addition, the passage area of the needle of the valve formed by the protrusion 14 with annular shape, the bellows metallic 15 and connection piece 16, can also be designed also in such a way that with increasing fuel pressure a growing force results in the fuel chamber 13, with the that the valve plate 4 is pressed against the seat of the needle valve 2. Choosing the hydraulic diameter, which comes determined by the projection 14, the metal bellows 15 and the piece of connection 16, there is thus the possibility of maintaining the needle of the injector valve 3 in the desired manner in terms of efforts of pressure, that is, almost pressure free, overcompensated or undercompensated.

The metal bellows 15 also has, due to its metallic material, of uniform functionality over a wide area Working temperature The length variations themselves thermal bellows 15 give rise, due to the low axial elastic constant of the metal bellows 15, only about efforts introduced so small that they are negligible in the valve needle 3 in axial direction. The metal bellows 15 it can also, due to its mechanical spring effect in the direction axial, also completely or partially replace the nozzle spring 5.

To transmit the multilayer actuator stroke piezoelectric 8 to the needle of the valve 3, an element of transmission between the drive unit and the needle of the valve 3. This transmission element then serves first as hydraulic game compensation element, to exclude all play between the piezoelectric multilayer actuator 8 and the needle of the valve 3. Furthermore, it can be carried out by means of the Transmission a career transformation.

The transmission element has a plunger primary 21 and a secondary plunger 23, which are arranged in a hole section that borders the protrusion 14 annularly in the housing 1. This hole section is configured in two steps, with a first section of hole 31 wider that goes after the drive unit, on which the primary piston sits 21 and a second section of smaller hole 32 that borders the stop 14 of the housing 1 and in which the plunger is arranged secondary 23. Primary piston 21 is essentially configured cylindrical and housed in the header plate 10 of the drive unit or, preferably, is connected to it fixedly by welding. They are preferably composed the header plate 10 and the primary piston for one piece. He secondary piston 23 is configured as a hollow cylinder e inserted into the rear end of the valve needle 3, being arranged the front surface facing the primary plunger 21 of the secondary piston 23 essentially in the same plane as the final surface of the valve needle 3. The valve needle 3 and the secondary plunger 23 are also joined together in a manner preferred by welding, but at least free of play and as rigid as possible mechanically.

The primary piston 21 and the secondary piston 23, they are also distanced from each other in such a way that between opposing frontal surfaces in the transition zone of the first section of hole 31 to the second section of hole 32, is a hydraulic chamber 22 is configured. In addition, it is provided in the transmission element an accumulator chamber 24 composed of two parts, which presents a first zone of accumulator chamber 241 in the inner hole 30, which is delimited by the surface lower front of the secondary piston 23 and by means of the connection 16 of the metal bellows 15 on the valve needle 3. This first accumulator chamber zone 241 is connected by a junction hole 223 configured without throttling in housing 1 with a second zone of accumulator chamber 242, which is arranged in the housing area 34 that delimits with the first hole section 31 around the drive unit. The second zone of accumulator chamber 242 is delimited by two corrugated bellows 25, 26, arranged concentrically with respect to each other and a ring pressure 27, which in turn is supported by a pressure spring 28, which rests on a perforated plate 29 in the housing area 34. The wavy bellows 25 inside is welded then between the inner face of the pressure ring 27 and the front front face of the primary piston 21, which protrudes from the first section of hole 31. The outer corrugated bellows 26 is welded on the outer face of the pressure ring 27 and one step of the housing 30 which borders the first section of hole 31. In the housing step 30 between both corrugated bellows 25, 26 the junction hole 223 opens.

The hydraulic chamber 22 and the accumulator chamber 24 are linked together by a strangulation gap 36, configured between the perimeter wall of the secondary piston 23 and the inner wall of the second section of hole 32, and by a choke gap 37 that is configured between the wall perimeter of the primary piston 21 and the inner wall of the first hole section 31. In addition, the entire interior space of the element transmission is filled with a hydraulic fluid, which is located under a small overpressure, generated by the spring of pressure 28, which loads the second through pressure ring 27 accumulator chamber area 242. Before filling the interior space of the hydraulic fluid transmission element, degasses this hydraulic fluid, to release any small ones gas bubbles in the liquid.

The injection valve with the element of Transmission works as follows:

To start the injection process, the 8-layer piezoelectric actuator across the lines electrical input 19. This results in the multilayer actuator piezoelectric 8 deviate axially and by means of the head 10 move the primary piston 21 in the hole section 31.

In the transmission element, the interstitium of throttling 36 in the secondary plunger 23 and the interstitium of throttling 37 in the primary piston 21, which generate a joint between the hydraulic chamber 22 and the accumulator chamber 24, they are sized in such a way that during typical times of control of the piezoelectric multilayer actuator 8 from 1 to 5 ms only an extremely small exchange of liquid can take place hydraulic between the hydraulic chamber 22 and the accumulator chamber 24. This means that the volume of the hydraulic fluid during the injection time is only determined by compressibility of the hydraulic fluid, and that the hydraulic chamber 22 can be considered as a rigid piston. The elastic constant c of the hydraulic chamber 22 can then be estimated as follows

\hskip0.5cm

y

\hskip0.5cm

V = A*H \Rightarrow dP = -1/(k V) * A dhk = -1 / V * \ delta

 \ hskip0.5cm 

Y

 \ hskip0.5cm 

V = A * H \ Rightarrow dP = -1 / (k V) * A dh

k: Compressibility of hydraulic fluid

V: Volume of the hydraulic chamber

P: Pressure

A: surface of hydraulic chamber section

h: height of the hydraulic chamber

with dF = dP / A \ Digh -1 / (k V) * A 2 dh

F: Force

result

c = -dF / dh \ Rightarrow c = A / (k h)

The previous equality shows that the constant elastic c of the hydraulic chamber 22 is the larger the more small is its height and the larger its surface is effective section. Simulation calculations have also shown that we must have thermal and pressure induced elongations of a maximum of 50 µm. To be able to consider the camera hydraulic 22 as rigid piston, the elastic constant c of the hydraulic chamber 22 must be in the range of 10 8 N / m or higher. This means that, under the assumption that the compressibility k of the hydraulic fluid is approx. 10 * 10 - 10 m 2 / N, which corresponds to a typical value for a hydraulic fluid, the desired value for the elastic constant c, for example with a sectional area of 1 cm2 and a height of 0.1 cm. The exact sizing of the height and sectional area of the hydraulic chamber 22 can nevertheless adapt in each case to the conditions in the chamber of injection, to achieve a compact constructive form.

Through the design of the hydraulic chamber 22 as a rigid piston, the movement of the primary piston is transmitted 21, which is activated by the piezoelectric multilayer actuator 8, directly and with few losses to the secondary piston 23. The secondary piston movement 23 is damped then only weakly by the hydraulic fluid found in the first zone of the accumulator chamber 241, since the hydraulic fluid surplus, due to the rapid increase in pressure in the first zone of the accumulator chamber 241, is driven out through the hole of connection without throttling 223 towards the second zone of the chamber accumulator 242. Both corrugated bellows 25, 26 arranged concentrically one with respect to another, which delimit the second zone of the accumulator chamber 242, they are designed in such a way that they are radially very rigid, but nevertheless in axial direction very soft. They are preferably used as corrugated bellows metal bellows, which essentially correspond to the bellows metal 15 of the needle guide. In this place it is nonetheless equally possible the use of elastomeric materials for corrugated bellows 25, 26. When hydraulic fluid is driven from the first zone of the accumulator chamber 241 through the hole of junction 223 towards the second zone of the accumulator chamber 242, it expands the second zone of the accumulator chamber 242 against the retaining force of the pressure spring 28 loading on the pressure ring 27 axially in the direction of the bottom plate 11 of the drive unit.

The movement initiated by the primary piston 21 in the secondary piston 23, move the valve needle 3 connected with the secondary piston 23 against the spring restoring force of nozzle 5 down, so that the valve plate 4 is lift off the valve seat 2 and the injection valve will opens. The longitudinal displacement of the multilayer actuator piezoelectric 8 is then transformed into a displacement of the secondary piston 23 and with it the valve needle 3, which corresponds to the relationship between the effective surfaces for the primary piston 21 and secondary piston 23 pressure in the hydraulic chamber 22. Through proper coordination between the surface of the primary piston and the surface of the piston secondary, for example an increase in the stroke of the multi-layer piezoelectric actuator 8 in relation to the stroke of the valve needle 3. This way you can make sure reliable that the extremely short stroke of the multilayer actuator piezoelectric 8 is sufficient under any condition of operation of the injection valve to open the needle of the valve 3.

The injection process ends when the multi-layer piezoelectric actuator 8 is discharged again through the electric input lines 19. In this way the multi-layer piezoelectric actuator 8 to its initial length, preventing the tubular spring 9 from reaching the piezoceramic being under tension during traction due to the effects of the inertia of the masses. Since the plunger primary 21 is connected by the header plate 10 fixedly with the drive unit, it also retracts by means of the contraction of the piezoelectric multilayer actuator 8 the plunger primary 21 from the first section of hole 31. In this way results in the hydraulic chamber 22 for a short time a pressure reduction which, due to connection times extremely short of the piezoelectric multilayer actuator 8 and to the small dimension of the throttle gap 36 in the plunger secondary 23, cannot be compensated immediately by subsequent creep of hydraulic fluid from the chamber accumulator 24 through the throttle interstices 36, 37. This pressure drop in the hydraulic chamber 22 in relation with the pressure that exists in the accumulator chamber 24, it results in a pressure difference, which falls through the face of the plunger secondary 23 oriented to the hydraulic chamber and the face of the secondary piston 23 oriented to the first chamber zone accumulator 241. In this way the replacement of the needle is supported of the valve 3 by means of the nozzle spring 5, whereby achieves a rapid closure of the injection valve, which has an impact favorably on the development of combustion.

Through the design corresponding to the invention of the transmission element, it is also possible to compensate automatically all thermal variations of length in the injection valve due to the fatigue effects of the unit actuation or caused by pressure. If for example it gets longer the valve needle 3 due to thermal elongation or due to the pressure of the injection valve in relation to the housing 1, then the secondary piston 23 is collected in the second section of hole 32. The throttle gap 36 in the plunger secondary 23 is further dimensioned in such a way that during thermal processes, which are in terms of time in the range from a few seconds to several minutes, it can be exchanged hydraulic fluid through the throttle interstices 36, 37 between the accumulator chamber 24 and the hydraulic chamber 22. When the secondary piston 23 is therefore advanced due to the thermal phenomena in the second section of hole 32, liquid flows hydraulic from the hydraulic chamber 22 through the throttle interstices 36, 37 towards the accumulator chamber 24 until it is reached again in the hydraulic chamber 22 and in the accumulator chamber 24 at a pressure balance. The compensation of length is then limited exclusively by the height of the hydraulic chamber 22.

For reliable operation of the element transmission is necessary in particular a waterproofing Airtight of the hydraulic fluid with respect to the fuel chamber and to the drive unit. This results in demands raised to the wavy bellows 25, 26, which are therefore preferably constituted as metal bellows. These bellows metallic are configured with a wavy shape, since this way a very small axial elastic constant can be achieved. The axial deformation of the metal bellows by means of a pressure load it is certainly not low, but it is almost completely eliminated, just like that the forces acting on the different undulations of the bellows, in its sum throughout the entire metal bellows. As form especially favorable for the undulations of the bellows has credited a composite geometry, considered in its section longitudinal, by semicircular segments linked to each other with straight intermediate sections. In relation to a sinusoidal evolution of the undulations, they present the walls composed by segments semicircular lower mechanical stresses in axial direction, with high axial flexibility.

The hydraulic fluid in the hydraulic chamber 22 and in the accumulator chamber 24 is, as indicated, under a small overpressure, generated by the pressure spring 28, which loads the pressure ring 27 of the second zone of the accumulator chamber 242. By this small overpressure, when it is filled at the same time with bubble free hydraulic fluid the transmission element, it is ensured that the rapid processes of connection of the piezoelectric multilayer actuator 8 does not result in Cavitations in the hydraulic fluid. The pressure spring 28 it may also be substituted alternatively, in part or by complete, due to the spring effect of corrugated bellows 25, 26. In addition, there is the possibility of anticipating the interstices of throttling 36, 37 in each case only in secondary pistons 23 or in primary plungers 21, whereby an exchange of hydraulic fluid between one of the zones of the accumulator chamber 241, 242 and the hydraulic chamber 22. However, they may be also provided interstices of throttling in the piston primary 21 and secondary plunger 23.

Figure 1 shows a valve injection that opens out. There is however the possibility of using the transmission element corresponding to the invention in an injection valve that opens inwards. As it shown in figure 2, the needle of the valve 3 by the nozzle spring 5 at a pressure voltage instead of a tensile tension, bringing the needle of valve 3 sits in rest state with a needle tip conical 104 on a conical valve seat 102 in the valve injection, below which a hole is configured Injection 103 to inject fuel into the machine combustion.

The injection valve shown in figure 2 works exactly as opposed to the injection valve shown in figure 1. For safety reasons, the valve injection is then designed in such a way that when there is no control action on the piezoelectric multilayer actuator 8, the injection valve is closed, that is, the needle tip 102 is pressed against the valve seat 104.

When the combustion machine starts, it will It also controls the piezoelectric multilayer actuator 8. This extends and thus slides the primary piston 21 towards the first hole section 31. The pressure increase thus resulting in the hydraulic chamber 22 is compensated through the interstitium of throttling 36 in the secondary plunger 23 and the interstitium of throttling 37 in the primary plunger 21, which deal with a hydraulic fluid exchange with the accumulator chamber 24. this way is then generated in fractions of a second again a equilibrium state in which the injection valve continues staying closed The injection valve works such that the valve needle 3 opens whenever the multilayer actuator piezoelectric 8 is discharged and in this way the piston recedes primary 21 and with it also the secondary plunger 23, to which it is valve needle fixed 3.

Figure 3 shows another constructive form of an injection valve that opens outward, in which the basic pressure on the hydraulic fluid is generated in the element transmission by means of a pressure spring 128 arranged centrally in the primary piston 121. To do this, the piston Primary 121 is configured as a kettle, being configured between the header plate 10 and a bottom surface of the primary piston 121 an additional third chamber zone accumulator 243. Primary piston 121 is then disposed of such that it extends with its bottom surface in the first section of hole 31. The side walls of the plunger primary 21 are on the contrary essentially in the area of the housing 34, in which the unit of drive

The pressure spring 128, arranged in the third zone of the accumulator chamber 243, is welded between the header plate 10 of the drive unit and a plate of pressure 127 that is planned in the third chamber zone accumulator 243. The pressure spring is then protected in relationship with the third zone of the accumulator chamber 243 by a metal bellows 125.

The second zone of the accumulator chamber 242 is configured between the header plate 10 of the multilayer actuator piezoelectric 8 and the step of the housing 35 around the wall of the primary piston 121. This second zone of the accumulator chamber 242 is connected by a connection hole 136 with the third zone of the accumulator chamber 243 in the primary piston 121. The operation of the transmission element shown in figure 3 corresponds to the transmission element represented in the Figure 1. When providing a pressure spring 128 located in the inside, however, a high basic pressure can be achieved as well as a constructive form given the most compact case of the element of transmission.

Instead of the pressure spring 128 located internally, the delimited volume can also be loaded gas-tight by the metal bellows 125 and the header plate 10 by a pressure gas, so that instead of the spring of mechanical pressure 128, a gas pressure spring of the maintenance of the basic pressure in the chamber areas accumulator 241, 242, 243.

The particularities of the invention given to know in the previous description, the drawings and the claims, can be significant both individually as well as in any combination for the realization of the invention in its different configurations.

Claims (11)

1. Device to transmit the movement of an actuator (8) to an adjustment body (3) with a transmission element that generates a union active between the actuator (8) and the adjustment body (3) and that determines a hydraulic chamber (22) and an accumulator chamber (24), that are filled with a hydraulic fluid and that are joined between yes through at least one strangulation gap (36, 37), presenting the transmission element a first and a second piston element (21, 23; 121), the first piston element (21; 121) fixedly with the actuator (8) and the second piston element (23) fixedly with the adjusting member (3), being configured between the first piston element (21; 121) and the second piston element (23) the hydraulic chamber (22) and including the accumulator chamber (24) a chamber zone accumulator (242, 243) charged with pressure, which is delimited by metal bellows, characterized in that the metal bellows form a system of corrugated bellows (25, 26, 125) and are prestressed by means of a spring element such that the area of the accumulator chamber is loaded with pressure and whose pressure is approximately constant. 2. Device according to claim 1, characterized in that the accumulator chamber zone (242, 243) loaded with pressure is charged by a pressure spring (28) through a pressure plate (27; 127). 3. Device according to claim 1, characterized in that the zone of the accumulator chamber (242, 243) loaded with pressure is charged by a gas pressure spring. 4. Device according to one of the claims 1 to 3, characterized in that the first piston element (21; 121) and the second piston element (23) are arranged in an area of an inner hole of the housing (1) configured in two steps, the first piston element (21) being distanced ; 121) and the second piston element (23) with each other in such a way that between the opposing front surfaces in the transition zone of a first hole section (31) to a second hole section (32) the hydraulic chamber (22), the stroke of the first piston element (21; 121) being transformed as a function of the relationship between the front surfaces on the second piston element (23). 5. Device according to claim 4, characterized in that the accumulator chamber (24) is configured in two parts, with a first accumulator chamber zone (241), delimited by the lower front surface of the second piston element (23) and a passage zone (14, 15, 16 ) in the adjusting member (3) and a second accumulator chamber zone (242), which is arranged in a housing area (34) that houses the actuator and which is connected to the first by means of a connecting hole (223). accumulator chamber zone (241), the second accumulator chamber zone (242) being limited by two corrugated bellows (25, 26) arranged concentrically with respect to each other and a pressure ring (27), on which a spring of loading pressure (28). 6. Device according to claim 4, characterized in that the first piston element (121) is shaped like a kettle and the accumulator chamber (24) is configured in three parts, with a first accumulator chamber zone (241), delimited by the lower front surface of the second element of piston (23) and a passage zone (14, 15, 16) in the adjustment member (3), a second accumulator chamber zone (242), which is configured in a housing area (34) that houses the actuator (8) around the first piston element (121) and a third zone of accumulator chamber (243), configured in the first piston element (121), the first zone of accumulator chamber (241) being connected with the second zone of accumulator chamber (242) by means of a first junction hole (223) in the housing (1) and the second accumulator chamber zone (242) with the third accumulator chamber zone (243) by a second junction hole (136) in the first piston element (121) and being arranged in the third accumulator chamber zone (243) a pressure spring (128), which is tensioned between a head plate (10) of the actuator (8) and a pressure plate (127) and which is delimited by a corrugated bellows (125 ) or a gas pressure spring. 7. Device according to one of the claims 1 to 6, characterized in that the actuator (8) is a multilayer piezoelectric actuator, which is prestressed by a spring element (9) and that the first piston element (21; 121) is fixedly housed in a header plate (10) of the multilayer actuator (8). 8. Device according to one of the claims 1 to 6, characterized in that the actuator operates according to the electrostrictive or magnetostrictive principle. 9. Device according to one of the claims 1 to 8, characterized in that the corrugated bellows (25, 26; 125) are metal bellows, which are preferably composed of semicircular segments with straight sections that are in each case between them. 10. Device according to one of the claims 1 to 9, characterized in that the corrugated bellows (25, 26; 125) are made of an elastomeric material. 11. Device according to one of the claims 1 to 10, characterized in that the hydraulic chamber (22) is designed such that the elastic constant of the hydraulic chamber (22) is at least 10 8 N / m.