Electromechanical actuator and actuator-valve unit

Abstract

The invention relates to an electromechanical actuator (1), in particular for actuating a valve (101) connectable thereto; comprising: a housing (2) with an interior (2.1); an electromagnetic actuating device (3) which is accommodated in the interior (2.1) of the housing; and a seal (4) which is configured to seal the interior (2.1) of the housing to the outside, wherein the housing (2) has at least one, in particular closable, leakage path (5) for checking the tightness of the seal (4), wherein fluid exchange between the interior (2.1) of the housing and outside (2.2) of the housing (2) is enabled by the leakage path (5). The invention also relates to an actuator-valve unit (100) comprising the electromechanical actuator (1).

Description

[0001] The invention relates to an electromechanical actuator and an actuator-valve unit.

[0002] Conventional electromechanical actuators (often simply called "actuators") typically consist of a housing with an interior cavity and an electromagnetic actuating device housed within that cavity. Such conventional actuating devices usually comprise a coil and an electromagnetically movable component, such as an armature, with current applied to the coil causing movement of the component. These conventional actuators often incorporate a seal to prevent external influences from the housing cavity.

[0003] These conventional configurations, however, have the disadvantage that the tightness of the seal is difficult to verify. The housings are typically sealed, so no fluid exchange can occur between the housing interior and the outside, particularly the atmosphere, at any point outside the seal. Therefore, if, for example, an external interface of the housing (such as a valve interface) where the seal is located is pressurized to test the seal, it is difficult to determine whether the seal itself or merely the housing is leak-proof.

[0004] The object of the invention is to overcome these disadvantages. In particular, it is an object of the invention to provide an electromechanical actuator on which a leak test can be carried out simply and reliably. It is also an object of the invention to provide an actuator-valve unit that has these advantages.

[0005] This problem is solved by the features of the independent claim. The dependent claims contain advantageous embodiments of the invention.

[0006] This problem is solved, in particular, by an electromechanical actuator according to claim 1. The actuator is specifically designed to actuate a valve that can be connected to it. The actuator comprises a housing with an interior. The actuator also comprises an electromagnetic actuating device, which is housed within the interior. Furthermore, the actuator has a seal, which is designed to seal the interior of the housing to the outside. The housing has at least one leakage path for verifying the tightness of the seal. The leakage path allows fluid exchange between the interior of the housing and outside the housing.

[0007] As explained above, the leakage path allows fluid exchange with the housing's environment, such as the atmosphere. This means that during a leak test as described above, fluid such as air can escape from the housing if the seal is not airtight and is subjected to (test) pressure. Such a pressure would therefore hardly rise, if at all, indicating that the seal is not airtight. Conversely, if the pressure rises accordingly, it can be concluded that the seal is airtight, since the housing is intentionally leaking via the leakage path. In other words, fluid exchange is preferably only permitted through the leakage path, assuming the seal is airtight.

[0008] Alternatively or in addition to the pressurization and pressure measurement described above, it can be checked whether the relevant fluid is present in the leakage path or is flowing through it. Based on the measured quantity, the degree of leakage in the seal can also be determined.

[0009] In preferred embodiments, at least one leakage path is closable. In particular, it is reclosable and (non-destructively) reopenable, allowing for repeated leak tests. It should be noted that the leakage path in this context is an intentional and explicitly designed leakage path and is not to be equated with a manufacturing defect or wear and tear from prolonged use / storage. The present at least one leakage path is to be understood as being in addition to such potential defects or wear. An alternative term for the present leakage path is preferably "venting channel" or "venting path," whereby the fluid to be vented need not necessarily be air.

[0010] At least one leakage path is preferably fluidly connected to the seal. In other words, one end of the leakage path (hereinafter referred to as the "first end") is sealed by the seal (provided the seal is tight) and an opposite end (hereinafter referred to as the "second end") is connected to the outside of the housing.

[0011] Preferably, in the present sense, "fluid exchange" refers to a fluid that is supplied externally by a leak detection device. Such a device is, for example, a fluid pump with a pressure sensor that detects and evaluates the pressure profile. The device can be connected to the actuator on the outside of the housing opposite the seal and / or to the actuator on the outside of the housing at one end of the leakage path (second end).

[0012] In preferred embodiments, the actuating device comprises a coil and at least one movable component. The movable component is electromagnetically movable by the coil and is, for example, an armature. The movable component, or armature, in turn causes a movement of an actuator, thereby actuating the actuating device.

[0013] In this case, part of the leakage path is formed between the coil and the armature. In other words, part of the leakage path runs through a gap between the coil and the armature. This part of the leakage path runs along an axial direction that is parallel to a longitudinal extension direction of the armature or parallel to a winding axis of the coil.

[0014] The actuating device preferably has a component that is stationary with respect to the housing. Such a stationary component is, for example, a pole core. A magnetic flux generated by the coil moves the armature towards the pole core, thereby actuating the actuating device or actuator.

[0015] Preferably, part of the leakage path is formed between the coil and the pole piece. In a preferred example, part of the leakage path runs through the gap between the coil and the armature and between the coil and the pole piece. The pole piece preferably has at least one pole piece groove on its radial outer surface, which forms part of the leakage path.

[0016] The pole core groove is preferably straight, in particular running parallel to the longitudinal direction or an axial direction of the actuator.

[0017] In some preferred embodiments, the pole core groove is helical. The pole core groove, or the leakage path portion formed by it, extends along the longitudinal direction as well as along a circumferential direction of the pole core.

[0018] In some preferred embodiments, the pole core has a pole core support disk, which preferably rests against the housing. The pole core support disk preferably forms a region of the largest radius or circumference of the pole core. More preferably, the pole core has at least one recess in the pole core support disk, which forms part of the leakage path.

[0019] Preferably, the pole piece has a plurality of such recesses distributed circumferentially, such that part of the leakage path runs through the at least one recess in the pole piece support disk, between the pole piece and the housing. The at least one recess in the pole piece support disk is preferably provided as an alternative or additional to the aforementioned clearance fit. The at least one recess is particularly slot-shaped. The at least one recess preferably extends along the axial direction to the pole piece groove and is connected to or continuous with it.

[0020] Advantageously, the housing has at least one recess which forms part of the leakage path. Particularly when multiple recesses are present, they are evenly distributed around the circumference of the pole core. The recess is preferably formed by cutting and / or milling, or more preferably during the overmolding process of a suitable mold for the housing. This allows the portion of the leakage path between the pole core and the housing to be manufactured particularly easily and cost-effectively.

[0021] The aforementioned housing recess(s) is / are preferably provided such that, particularly in the case of several, it is radially opposite the preferred pole core groove and / or the preferred recess in the pole core support disk.

[0022] Preferably, the armature and the pole piece, as well as a variable air gap between them, are jointly enclosed by a sleeve, the sleeve sealing the aforementioned components from the housing interior and, in particular, the aforementioned gap. In this configuration, part of the leakage path is formed between the sleeve and the coil. For this purpose, in some preferred examples, a radial distance between the sleeve and the coil can be formed along the entire length of the leakage path. The aforementioned pole piece groove preferably extends outside the sleeve with respect to the longitudinal extent of the pole piece. In other words, preferably only a portion of the pole piece (with respect to its longitudinal extent) is enclosed by the sleeve, with the other portion preferably having the pole piece groove.

[0023] Advantageously, one external end of the leakage path (second end) is formed by a through-hole in the housing. This through-hole is fluidly connected to the interior of the housing.

[0024] Preferably, the through-hole has a circular or rectangular cross-section. In particular, the through-hole is a channel.

[0025] Preferably, at least part of the through-hole passes through a connector of the actuator, to which a control unit for the actuating device can be connected. Such a connector has, for example, electrical pins or terminals that are electrically connected to the coil of the actuating device and enable control or energizing of the coil. The through-hole is preferably spatially separated from the terminals. In other words, the aforementioned through-hole is not an opening or bore for the terminals, but rather an additional through-hole for forming the leakage path and connecting it to the outside. Any openings or bores for the terminals are not fluidly connected to the interior of the housing, but are connected to the coil at a separate location within the housing.

[0026] Advantageously, the through-hole for the leakage path has a fluid connection that can be connected to a fluid supply device for checking the tightness of the seal. Such a fluid supply device could be, for example, the aforementioned leak testing device and could be an air pump, an oil pump, a water pump, etc. The fluid connection could be, for example, a hose connection, a screw connection, or the like.

[0027] In some preferred embodiments, the actuator further comprises a retaining bracket which is configured to fix the actuating device in the housing and preferably to close the magnetic circuit. The retaining bracket is at least partially in a clearance fit or an interference fit with the actuating device. Alternatively or additionally to the clearance fit, the retaining bracket has at least one recess or groove which forms part of the leakage path. At locations where the retaining bracket has the recess or groove and is in contact with the actuating device, the retaining bracket is preferably in an interference fit with the actuating device. At locations where the retaining bracket does not have a recess or groove and is in contact with the actuating device, the retaining bracket is preferably in a clearance fit with the actuating device to form the leakage path.

[0028] Preferably, the recess or groove of the retaining bracket described above is additionally or alternatively available to the pole piece groove or to a recess or groove in the sleeve and / or anchor at the corresponding locations.

[0029] The retaining bracket has, in particular, at least one, preferably two, annular holders in which the actuating device is received. For example, the retaining bracket has a first annular holder through which the armature passes axially, and a second annular holder through which the pole core passes. These annular holders preferably receive the corresponding component in a clearance fit, such that the leakage path runs between the retaining bracket and the corresponding component. Alternatively or additionally, the annular holders have recesses or grooves on their inner circumference through which the leakage path runs.

[0030] The present invention also relates to an actuator-valve unit. The actuator-valve unit comprises the electromechanical actuator according to one of the preceding embodiments. Furthermore, the actuator-valve unit comprises a valve, wherein the valve is connected to the leakage path of the actuator via the seal. The valve is actuated by the actuator by means of the actuating device, i.e., opened and closed. In the case where the seal is leaking, the valve is fluidly connected to the leakage path. In the case where the seal is tight, the valve is not fluidly connected to the leakage path.

[0031] Preferably, the seal is configured to seal the actuator housing interior against the valve. In other words, assuming the seal is tight, the valve is not fluid-connected to the housing interior. This allows for a leak test of the seal to be performed even when the actuator-valve unit is assembled, i.e., when the actuator and valve are connected. The valve can be pressurized with fluid, and the pressure profile can be observed. Alternatively or additionally, it can be checked at the other end of the leakage path whether the relevant fluid is flowing through it.

[0032] The invention also relates to methods for leak testing as described above. Such a method comprises, for example, the following steps: As a first step, if the leakage path, especially its second end, is closed, the leakage path can be opened non-destructively, for example by removing a plug or cover.

[0033] In a second step, the seal is subjected to fluid, especially under pressure.

[0034] In a third step, a pressure profile is recorded at the seal and / or it is checked whether the fluid is present in the leakage path or is flowing through it.

[0035] The aforementioned steps can be performed on the actuator and / or on the combined actuator-valve unit.

[0036] Further details, advantages and features of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows: Fig. 1 a schematic sectional view of an electromechanical actuator according to a first embodiment of the invention; Fig. 2 an enlarged detail view of the actuator according to the first embodiment; Fig. 3 a schematic detail view of a component of the actuator according to the first embodiment; Fig. 4 a schematic external view of the actuator according to the first embodiment; and Fig. 5 a schematic sectional view of an actuator-valve unit showing the electromechanical actuator according to the first embodiment.

[0037] The Fig. Figure 1 shows a schematic sectional view of an electromechanical actuator 1 (hereinafter referred to as "actuator 1") according to a first embodiment of the invention. Fig. Figure 2 shows an enlarged detail view of actuator 1 according to the first embodiment. The figure shows... Fig. 2 one opposite the Fig. 1 View rotated about an axial direction 9 to illustrate a leakage path 5 described below, which is in Fig. 1 is partially shown. Fig. Figure 3 shows a schematic detail view of a component 3.3 of the actuator 1 according to the first embodiment, wherein said component 3.3 is a pole core 3.3 as explained below. Fig. Figure 4 shows a schematic external view of the actuator 1 according to the first embodiment.

[0038] First, the basic structure and function of actuator 1 will be explained using the Fig. 1 explained. An axial direction 9 of the actuator 1 is in Fig. Figure 1 is shown. Furthermore, a radial direction 10 perpendicular to the axial direction 9 of the actuator 1 is shown.

[0039] The actuator 1 has a housing 2. The housing 2 is preferably an injection-molded component in which an electromagnetic actuating device 3, described below, is preferably overmolded with plastic. An external view of the actuator 1, in particular of the housing 2, is also shown in Fig. 4 shown (explained below).

[0040] The actuator 1 also includes the electromagnetic actuating device 3. The actuating device 3 is housed in an interior compartment 2.1 of the housing 2. Furthermore, the actuator 1 has a seal 4 which seals the interior compartment 2.1 from the outside. An environment or atmosphere 2.2 outside the housing 2 is characterized. The environment 2.2 can be air or a liquid such as water or oil and, in this sense, characterizes a region 2.2 outside the housing 2 (alternatively also referred to as the "housing exterior").

[0041] In the present embodiment, the actuating device 3 comprises a coil 3.1 and an armature 3.2, which is moved electromagnetically by the coil 3.1. A back-and-forth movement direction 11 of the armature 3.2 is defined in Fig. 1 marked. This runs parallel to the axial direction 9. Furthermore, the actuating device 3 has a pole core 3.3 for closing the magnetic circuit as well as an actuating element or plunger 7, which is moved by the armature 3.2 and causes actuation of the actuator 1.

[0042] The actuator 1 also has a retaining bracket 6, which is designed to fix the actuating device 3 in the housing 2. For this purpose, the retaining bracket 6 has two ring-shaped holders 6.2, 6.3 in which the actuating device 3 is received.

[0043] For example, the retaining bracket 6 has a first annular holder 6.2 through which the armature 3.2 runs axially, and a second annular holder 6.3 through which the pole piece 3.3 runs. In the sectional view of the Fig. For easier overview, the two holders 6.2 and 6.3 have also been cut.

[0044] For example, if a leak test is carried out at the factory after the actuator 1 has been manufactured, the actuator 1 is typically pressurized with a fluid at the location on the housing 2 or the actuator 1 designated by reference numeral 13, and the pressure profile is recorded. However, it is usually difficult to determine whether the seal 4 or the housing 2 of the actuator 1 is leak-proof. Location 13 represents, in particular, a connection point for a connectable valve 101 or any other actuating device.

[0045] Again Fig. As can be seen from Figure 1, the seal 4 is preferably arranged at this point 13. Preferably, the seal 4 is arranged at an actuating end of the actuating device 3, in particular at an outwardly acting end of the plunger 7, and seals this area from the housing interior 2.1.

[0046] For this purpose, the housing 2 of the actuator 1, as described below with reference to the Fig. As explained in more detail in Section 2, the leakage path 5 mentioned at the outset is used to check the tightness of the seal 4. The leakage path 5 allows fluid exchange between the housing interior 2.1 and the outside 2.2 of the housing 2. In other embodiments, the actuator 1 can also have more than one leakage path 5. The at least one leakage path 5 is preferably fluidly connected to the seal 4. The leakage path 5 is sealed off from the environment 2.2 of the housing 2 by the seal 4 (assuming the seal 4 is tight). If the seal 4 is not tight, the housing interior 2.1 is fluidly connected to the environment 2.2 via the leaking seal 4 through the leaking seal 4 by means of the leakage path 5.

[0047] In the present embodiment, the leakage path 5 has a first end 5.1 and a second end 5.2, wherein the first end 5.1 is connected to the seal 4 and the second end 5.2 is directly fluid-connected to the environment 2.2. In other words, a first end 5.1 of the leakage path 5 is sealed by the seal 4 (provided the seal is tight) and an opposing second end 5.2 is connected to the outside of the housing 2.

[0048] The leakage path 5 runs in the present embodiment and as in Fig. 2 shown starting from the seal 4, i.e. the first end 5.1, along the axial direction 9 as follows.

[0049] Part of the leakage path 5 runs between the pole piece 3.3 and the housing 2. For this purpose, the pole piece 3.3 is held in the housing 2 by means of a clearance fit. Alternatively or additionally, the pole piece 3.3, as shown in Fig. 3 shown, on its radial outer surface 3.4 a pole core groove 3.5 which is spiral in this case.

[0050] Furthermore, the polar core 3.3 shows, as from Fig. As shown in Figure 3, a pole core support disk 3.7 is provided, which preferably rests against the housing 2. The pole core 3.3 further has at least one recess 3.8, preferably a plurality of such recesses 3.8 distributed in the circumferential direction of the pole core 3.3, so that the leakage path 5 runs through the at least one recess 3.8 in the pole core support disk 3.7, between the pole core 3.3 and the housing 2. The at least one recess 3.8 in the pole core support disk 3.7 is provided as an alternative or additional feature to the aforementioned clearance fit. The at least one recess 3.8 is particularly slot-shaped. The at least one recess 3.8 preferably extends to the pole core groove 3.5.

[0051] Alternatively or in addition to the above explanations, in particular regarding the leakage path 5 between the pole core 3.3 and the housing 2, the housing 2 preferably has at least one housing recess 2.6, as shown in Fig. 4 shown. Fig. Figure 4 shows an external view of actuator 1 with a view along the axial direction 9 into the Fig. 1 and Fig. 2, i.e., with regard to point 13 (connection point 13) of the housing 2.

[0052] The housing 2 has a plurality, more precisely six, of such housing recesses 2.6, which are evenly distributed in the circumferential direction of the pole piece 3.3. One of these housing recesses 2.6 is also located in the Fig. 2 and Fig. 5 is shown with a dashed line. Here, the recessed part 2.6 of the housing 2 is cut out or milled, or is formed during overmolding of a mold for the housing 2.

[0053] This makes it particularly easy and cost-effective to provide the leakage path 5 between the pole core 3.3 and the housing 2.

[0054] The aforementioned housing recess(s) 2.6 is / are preferably provided such that, particularly in the case of several, it is radially opposite the preferred pole core groove 3.5 and / or the preferred recess 3.8 in the pole core support disk 3.7.

[0055] Subsequently, another part of the leakage path 5 runs between the retaining bracket 6 or the second annular holder 6.3 and the pole core 3.3. Here, the retaining bracket 6 preferably has a clearance fit with the pole core 3.3. Alternatively or additionally, the pole core groove 3.5 runs (see Fig. 3) at this very point of the second annular holder 6.3. Alternatively or additionally, the second annular holder 6.3 has recesses or grooves 6.1, as shown in Fig. 1 indicated.

[0056] Preferred are sections of the retaining bracket 6 in which it contacts components of the actuating device and has no recesses or grooves 6.1, with said components in a clearance fit to form the leakage path via the clearance fit. Further preferred are sections of the retaining bracket 6 in which it contacts components of the actuating device and has recesses or grooves 6.1, with said components in an interference fit to form the leakage path via the recesses or grooves 6.1. A similar relationship applies to the preferred presence of the pole core groove 3.5 (or correspondingly via a clearance fit) on a common contact surface with the retaining bracket 6.

[0057] Another part of the leakage path 5 runs between the coil 3.1 and the pole core 3.3, as well as between the coil 3.1 and the armature 3.2. In this example, the actuating device 3 has a sleeve 8 for receiving an elongated (with respect to its longitudinal extent) portion of the pole core 3.3 and the armature 3.2, wherein the armature 3.2 is completely enclosed by the sleeve 8 with respect to its longitudinal extent. The sleeve 8 is spaced radially 10 apart from the coil 3.2 and from a bobbin 3.6 thereof. Alternatively or additionally, the sleeve 8 also has a groove, preferably helical, on an outer surface radially opposite the coil 3.2 (not shown).

[0058] The leakage path 5 continues between the anchor 3.2 and the first annular holder 6.2. The first annular holder 6.2 has, in this example, a configuration identical to the second annular holder 6.3.

[0059] The housing 2 has a through-hole 2.5, which is fluidly connected to the housing interior 2.1. The through-hole 2.5 partially passes through a connector 2.3, to which a control unit for the actuating device 3 can be connected via terminals 12. As shown in the Fig. As can be seen from Figure 2, the through-hole 2.5 runs separately from the connections 12 and is spaced apart from them at least along the axial direction 10. The connections 12 do not pass through the through-hole 2.5.

[0060] The second end 5.2 of the leakage path 5, which is an external end, runs through the through-hole 2.5 of the housing 2. The housing has a fluid connection 2.4, which is resealable and re-openable (non-destructively). For this purpose, the fluid connection 2.4 has, for example, a removable screw or plug-in cover. A leak testing device, such as a fluid pump, can be connected externally to this fluid connection 2.4 to check the tightness of the seal 4.

[0061] The leakage path 5 described above ensures a fluid connection between the housing interior 2.1, specifically the seal 4, and the environment 2.2 outside the housing 2. This guarantees a reliable and accurate leak test of the actuator 1 and the seal 4.

[0062] Fig. Figure 5 shows a schematic sectional view of an actuator-valve unit 100 comprising the electromechanical actuator 1 according to the first embodiment.

[0063] The present actuator-valve unit 100 also includes a valve 101. The valve 101 is connected to the leakage path 5 via the seal 4. Furthermore, in Fig. Figure 5 shows a fluid flow 14 which is connected from the valve 101 via the seal 4 to the leakage path 5.

[0064] If the actuator-valve unit 100 is now pressurized with fluid / pressure on the valve side, the pressure in the valve 101 increases if the seal 4 is tight. Otherwise, the fluid 14 flows through the leakage path 5 and leaves the housing interior 2.1 at the external second end 5.2 of the leakage path 5.

[0065] The present configuration also allows verification of whether an additional seal 4.1, which seals the actuator-valve unit 100 against the environment 2.2, is leak-tight. If the aforementioned leak test reveals that the seal 4 is leak-tight, a pressurized fluid can be introduced at the second end 5.2 of the leakage path 5. If a leak is detected, it can be concluded that the additional seal 4.1 is leaking.

[0066] In addition to the foregoing written description of the invention, explicit reference is hereby made to the graphic representation of the invention in the following for its supplementary disclosure. Fig. Reference is made to 1 to 5. Reference symbol list 1 actuator 2 cases 2.1 Interior of the housing 2.2 Environment of the housing 2.3 Connector plug 2.4 Fluid connection 2.5 Through hole 2.6 Housing recess 3 Actuating device 3.1 Coil 3.2 Anchor 3.3 Pole piece 3.4 radial outer surface of the polar core 3.5 Pole piece slot 3.6 Bobbin 3.7 Pole piece support disc 3.8 Recess 4 Sealing 4.1 Sealing 5 Leakage path 5.1 first end 5.2 second end 6 retaining brackets 6.1 Recess / grooves in the retaining bracket 6.2 First ring-shaped holder 6.3 second ring-shaped holder 7 Actuator / Plunger 8 Sleeve 9 Axial direction 10 Radial direction 11 Back-and-forth movement 12 connections 13th position of the case 14 Fluid flow

Claims

Electromechanical actuator (1), in particular for actuating a valve (101) connectable thereto; comprising: a housing (2) with a housing interior (2.1); an electromagnetic actuating device (3) which is received in the housing interior (2.1); and a seal (4) which is configured to seal the housing interior (2.1) to the outside, wherein the housing (2) has at least one, in particular closable, leakage path (5) for checking the tightness of the seal (4), wherein fluid exchange between the housing interior (2.1) and outside (2.2) of the housing (2) is enabled by the leakage path (5). Electromechanical actuator (1) according to claim 1, wherein the actuating device (3) has a coil (3.1) and an armature (3.2) which is moved electromagnetically by the coil (3.1), and wherein part of the leakage path (5) is formed between the coil (3.1) and the armature (3.2). Electromechanical actuator (1) according to claim 2, wherein the actuating device (3) has a pole core (3.3) which has at least one pole core groove (3.5) on a radial outer surface (3.4) which forms part of the leakage path (5), wherein the pole core groove (3.5) is in particular spiral-shaped. Electromechanical actuator (1) according to claim 3, wherein the housing (2) has at least one housing recess (2.6) which forms part of the leakage path (5) and which is in particular radially opposite the pole core groove (3.5). Electromechanical actuator (1) according to one of the preceding claims, wherein an outer end (5.2) of the leakage path (5) is formed by a through-hole (2.5) in the housing (2) which is fluidly connected to the housing interior (2.1). Electromechanical actuator (1) according to claim 5, wherein at least a part of the through-hole (2.5) passes through a connector (2.3) with which a control of the actuating device (3) can be connected. Electromechanical actuator (1) according to claim 5 or claim 6, wherein the through-bore (2.5) has a fluid connection (2.4) which can be connected to a fluid supply device for checking the tightness of the seal (4). Electromechanical actuator (1) according to one of the preceding claims, further comprising a retaining bracket (6) which is configured to fix the actuating device (3) in the housing (2), wherein the retaining bracket (6) is at least partially in clearance fit with the actuating device (3) and / or has a recess (6.1) which forms part of the leakage path (5). Actuator-valve unit (100) comprising the electromechanical actuator (1) according to one of the preceding claims and a valve (101), wherein the valve (101) is connected to the leakage path (5) via the seal (4). Actuator-valve unit (100) according to claim 9, wherein the seal (4) is configured to seal the housing interior (2.1) of the actuator (1) against the valve (101).

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