[0001] The invention relates to an actuator arrangement and an injection valve.
[0002] Actuator arrangements are in wide spread use, in particular injection valves for
instance for internal combustion engines comprise actuator arrangements, which comprise
solid state actuator units. In order to inject fuel, the solid state actuator unit
is energized so that a fluid flow through the fluid outlet portion of the injection
valve is enabled. To enable fast response times electric energy needs to be transmitted
to or from the actuator arrangement in a very fast way.
[0003] The object of the invention is to create an actuator arrangement that is simply to
be manufactured and which enables reliable operation.
[0004] This object is achieved by the features of the independent claims. Advantageous embodiments
of the invention are given in the sub-claims.
[0005] According to a first aspect the invention is distinguished by an actuator arrangement,
comprising a solid state actuator unit with a longitudinal axis comprising a solid
state actuator, a connecting element for connecting the solid state actuator to a
compensator unit, electric pins being electrically coupable to a power supply, and
a supporting element being designed and arranged to at least partly take in the connecting
element and the electric pins. The solid state actuator unit comprises a first axial
end area designed to act as drive side and a second axial end area facing away from
the first axial end area. The actuator arrangement comprises the compensator unit
being arranged facing the second axial end area of the solid state actuator unit along
the longitudinal axis of the solid state actuator unit and being in contact with the
solid state actuator unit via the connecting element.
[0006] This has the advantage that in a simple way the two components, the connecting element
and the supporting element, instead of one component as used in general are simply
to be manufactured. They may be made of different materials and/or properties. For
example, for the supporting element a material can be chosen, which is easy to be
welded. Furthermore, the manufacturing of the connecting element and the supporting
element can be simplified compared to the case of one component, which may need to
be partially hardened. This has the advantage of low production costs.
[0007] In an advantageous embodiment the connecting element is fully hardened.
[0008] This contributes to the transmission of an axial force of the compensator unit to
the solid state actuator without deformation of the connecting element. In particular,
the supporting element does not need to comprise a material that can be hardened.
Therefore, especially reliable operation of the actuator arrangement may be enabled.
[0009] In a further advantageous embodiment the connecting element comprises stainless steel.
[0010] This has the advantage that oxidation problems may be reduced, if the connecting
element comprises stainless steel.
[0011] Therefore, especially reliable operation of the actuator arrangement may be enabled.
[0012] In a further advantageous embodiment the supporting element comprises stainless steel.
[0013] The supporting element does not need to comprise a material that can be hardened.
Thus, a material may be chosen, which is easy to be welded. Therefore, the supporting
element may allow the passage of the electric pins and may be easily welded. The supporting
element may for example comprise any standard stainless steel. This has the advantage
that oxidation problems may be reduced. Therefore, especially reliable operation of
the actuator arrangement may be enabled.
[0014] In a further advantageous embodiment the supporting element comprises stainless steel,
which comprises around 0.05% carbon, 18% chromium and 10% nickel and in particular
0.05% carbon, 18% chromium and 10% nickel.
[0015] By this, oxidation problems may be reduced in an especially reliable way. Therefore,
especially reliable operation of the actuator arrangement may be enabled.
[0016] According to a second aspect the invention is distinguished by an injection valve
with a valve assembly within a recess of a housing body and an actuator arrangement
of the first aspect of the invention, comprising a solid state actuator unit within
the recess, wherein the solid state actuator unit is designed for acting on the valve
assembly.
[0017] Exemplary embodiments of the invention are explained in the following with the help
of schematic drawings. These are as follows:
- Figure 1,
- an actuator arrangement,
- Figure 2,
- a specific actuator arrangement in an injection valve.
[0018] Elements of the same design and function that appear in different illustrations are
identified by the same reference characters.
[0019] Figure 1 shows an actuator arrangement 10 comprising a solid state actuator unit
12 and a compensator unit 14.
[0020] The solid state actuator unit 12 has a longitudinal axis A and comprises a solid
state actuator 16, a connecting element 18 for connecting the solid state actuator
16 to the compensator unit 14, electric pins 20 being electrically coupable to a power
supply, and a supporting element 22 being designed and arranged to at least partly
take in the connecting element 18 and the electric pins 20.
[0021] For example, the electric pins 20 might be coupled by weldings, in particular resistance
weldings, or soldered connections to an electric conductor 64 (figure 2), which is
supplied with electric energy. In particular, injection valves for instance for internal
combustion engines may comprise the actuator arrangement 10.
[0022] The solid state actuator 16 changes its length in axial direction depending on a
control signal applied to it such that electric energy supplied to it or is taken
away from it. The solid state actuator unit 12 is typically a piezo actuator unit.
It may however also be any other solid state actuator unit known to the person skilled
in the art such as a magnetostrictive actuator unit.
[0023] The solid state actuator unit 12 comprises a first axial end area 24 designed to
act as drive side and a second axial end area 26 facing away from the first axial
end area 24, in particular facing the compensator unit 14. On the drive side of the
solid state actuator unit 12 facing the first axial end area 24 optional actuating
elements are arranged such as a valve needle or a rotor.
[0024] The compensator unit 14 is arranged facing the second axial end area 26 of the solid
state actuator unit 12 along the longitudinal axis A of the solid state actuator unit
12 and is mechanically coupled to the connecting element 18 of the solid state actuator
unit 12. The compensator unit 14 enables to set an axial preload force on the solid
state actuator unit 12 via the connecting element 18 of the solid state actuator unit
12. In particular, the compensator unit 14 is a thermal compensator unit, which is
enabled to compensate temperature changes.
[0025] The connecting element 18 of the solid state actuator unit 12 is arranged along the
longitudinal axis A of the solid state actuator unit 12. In particular, the connecting
element 18 is getting locked within the supporting element 22 and the solid state
actuator 16. The supporting element 22 is designed and arranged to at least partly
take in the connecting element 18 and the electric pins 20 facing the second axial
end area 26 of the solid state actuator unit 12. In particular, the electric pins
20 protrude in the supporting element 22. In particular, the connecting element 18
protrudes in the supporting element 22.
[0026] Since the solid state actuator unit 12 comprises two components, the connecting element
18 and the supporting element 22, instead of one component as used in general, the
connecting element 18 and the supporting element 22 can be made of different materials
and/or properties. Furthermore, the manufacturing of the connecting element 18 and
the supporting element 22 can be simplified compared to the case of one component,
which needs to be partially hardened. This has the advantage of low production costs.
In particular, the connecting element 18 can be fully hardened. Thus, the connecting
element 18 may allow the transmission of an axial force of the compensator unit 14
to the solid state actuator 16 without deformation. For the supporting element 22
a material can be chosen, which is easy to be welded. Therefore, the supporting element
22 may allow the passage of the electric pins 20 and may be easily welded. In particular,
the supporting element does not need to comprise a material that can be hardened.
[0027] For example, if the supporting element 22 comprises any standard stainless steel
and/or the connecting element 18 comprises stainless steel, corrosion problems may
be reduced in a simple way. For example, the supporting element 22 may comprise about
0.05% carbon, 18% chromium and 10% nickel, which corresponds to X5CrNi18-10 (EN-standard)
and is registered at the American Iron and Steel Institute (AISI) as AISI 304. By
this, oxidation problems may be reduced in an especially reliable way. Thus, reliable
operation of the actuator arrangement may be enhanced. In particular, electric connections
and resistance weldings between the supporting element 22, the electric pins 20 of
the solid state actuator unit 12 and the power supply can be protected against problems
resulting from corrosion.
[0028] Figure 2 shows an injection valve 28 that may be used as a fuel injection valve for
an internal combustion engine. The injection valve 28 comprises a valve assembly 30,
the actuator arrangement 10 and a connector 32. The actuator arrangement 10 comprises
the solid state actuator unit 12 and the compensator unit 14.
[0029] The injection valve 28 has a two-part housing body 34, 36 with a tubular shape with
the central longitudinal axis A. The housing body 34, 36 of the injection valve 28
comprises a recess 38 which is axially led through the housing body 34, 36.
[0030] The solid state actuator unit 12 is arranged within the recess 38 of the housing
body 34, 36 and comprises the electric pins 20 being electrically coupable to a power
supply.
[0031] An actuator housing enclosing the solid state actuator 16 of the solid state actuator
unit 12 may comprise a spring tube 40 and a cap 42. Part of the cap 42 may form at
least part of the first axial end area 24 comprising the drive side of the solid state
actuator unit 12. The solid state actuator unit 12 further comprises the connecting
element 18 and the supporting element 22. The connecting element 18 may apply an axial
preload force on the solid state actuator unit 12.
[0032] The valve assembly 30 comprises a valve body 44 and a valve needle 46. The valve
body 44 has a valve body spring rest 48 and the valve needle 46 comprises a valve
needle spring rest 50, both spring rests 48, 50 supporting a spring 52 arranged between
the valve body 44 and the valve needle 46. Between the valve needle 46 and the valve
body 44 a bellow 54 is arranged, which is sealingly coupling the valve body 44 with
the valve needle 46. By this a fluid flow between the recess 38 and a chamber 56 is
prevented. Furthermore, the bellow 54 is formed and arranged in a way that the valve
needle 46 is actuable by the solid state actuator unit 12.
[0033] A fluid outlet portion 58 is closed or open depending on the axial position of a
valve needle 46. By changing its length, the solid state actuator 16 can exert a force
to the valve needle 46. The force from the solid state actuator 16 being exerted on
the valve needle 46 in an axial direction allows or respectively prevents a fluid
flow through the fluid outlet portion 58. Furthermore, the injection valve 28 has
a fluid inlet portion 60, which is arranged in the housing body 34, 36 and which for
instance is coupled to a not shown fuel connector. In this example, the fuel connector
is designed to be connected to a high pressure fuel chamber of an internal combustion
engine, the fuel is stored under high pressure, for example, under the pressure above
200 bar.
[0034] The valve assembly 30 is arranged in the injection valve 28 facing the first axial
end area 24 on the drive side of the solid state actuator unit 12 in a part of the
recess 38 of the housing body 34 of the injection valve 28 along the longitudinal
axis A.
[0035] The compensator unit 14, which is in this example a thermal compensator unit, is
arranged facing the second axial end area 26 of the solid state actuator unit 12 and
is mechanically coupled to the connecting element 18 of the solid state actuator unit
12. In particular, the compensator unit 14 enables to set an axial preload force on
the solid state actuator unit 12 via the connecting element 18 to compensate changes
of the fluid flow through the fluid outlet portion 58 in the case of temperature changes
of the injection valve 28.
[0036] The injection valve 28 further comprises the connector 32 with a non-conductive connector
body 62 in which an electric conductor 64 is arranged. Electric energy can be supplied
to the electric conductor 64 of the connector 32. Furthermore, the solid state actuator
unit 12 comprises an adapter 66 comprising terminal elements 68. The electric conductor
64 of the connector 32 is electrically coupled to one of the terminal elements 68
of the adapter 66 which is electrically coupled to another of the terminal elements
68 which on its part is electrically coupled to the electric pins 20 of the solid
state actuator 16. Consequently, electric energy can be simply supplied to the solid
state actuator 16 or respectively taken away from the solid state actuator 16 via
the connector 32.
[0037] The connecting element 18 is arranged in-between the solid state actuator 16 and
the compensator unit 14, wherein the connecting element 18 may be conterminous to
a spring rest of the compensator unit 14.
[0038] In the following, the function of the injection valve 28 will be described in detail:
[0039] The fluid is led from the fluid inlet portion 60 through the housing body 34, 36
to the fluid outlet portion 58.
[0040] The valve needle 46 prevents a fluid flow through the fluid outlet portion 58 in
the valve body 44 in a closing position of the valve needle 46. Outside of the closing
position of the valve needle 46, the valve needle 46 enables the fluid flow through
the fluid outlet portion 58.
[0041] The solid state actuator 16 may change its axial length if it is energized. By changing
its length the solid state actuator 16 may exert a force on the valve needle 46. The
valve needle 46 is able to move in axial direction out of the closing position. Outside
the closing position of the valve needle 46 there is a gap between the valve body
44 and the valve needle 46 at the first axial end area 24 of the injection valve 28
facing away from the solid state actuator 16. The spring 52 can force the valve needle
46 via the valve needle spring rest 50 towards the solid state actuator 16. In the
case the solid state actuator 16 is de-energized, the solid state actuator 16 shortens
its length. The spring 52 can force the valve needle 46 to move in axial direction
in its closing position. It is depending on the force balance between the force on
the valve needle 46 caused by the solid state actuator 16 and the force on the valve
needle 46 caused by the spring 52 whether the valve needle 46 is in its closing position
or not.
1. Actuator arrangement (10), comprising
- a solid state actuator unit (12) with a longitudinal axis (A) comprising
- a solid state actuator (16),
- a connecting element (18) for connecting the solid state actuator (16) to a compensator
unit (14),
- electric pins (20) being electrically coupable to a power supply, and
- a supporting element (22) being designed and arranged to at least partly take in
the connecting element (18) and the electric pins (20),
wherein the solid state actuator unit (12) comprises a first axial end area (24) designed
to act as drive side and a second axial end area (26) facing away from the first axial
end area (24), and
- the compensator unit (14) being arranged facing the second axial end area (26) of
the solid state actuator unit (12) along the longitudinal axis (A) of the solid state
actuator unit (12) and being in contact with the solid state actuator unit (12) via
the connecting element (18).
2. Actuator arrangement (10) according to claim 1, wherein the connecting element (18)
is fully hardened.
3. Actuator arrangement (10) according to one of the preceding claims, wherein the connecting
element (18) comprises stainless steel.
4. Actuator arrangement (10) according to one of the preceding claims, wherein the supporting
element (22) comprises stainless steel.
5. Actuator arrangement (10) according to claim 4, wherein the stainless steel comprises
around 0.05% carbon, 18% chromium and 10% nickel.
6. Injection valve (28) with a valve assembly (30) within a recess (38) of a housing
body (34, 36) and an actuator arrangement (10) according to one of the preceding claims,
comprising a solid state actuator unit (12) within the recess (38), wherein the solid
state actuator unit (12) is designed for acting on the valve assembly (30).