Lubricant pump

Abstract

The invention relates to a pump unit (4) for a lubricant pump (100) with a pump housing (6) which is designed to be connected to a lubricant reservoir (2), wherein the pump housing (6) has a lubricant receiving chamber (12) having at least one lubricant outlet (20), wherein at least one pump element (14) can be arranged in the lubricant receiving chamber (12) and is designed to transport lubricant from the lubricant reservoir (2) via the lubricant receiving chamber (12) to the lubricant outlet (20), wherein the pump housing (6) also has an integrally formed base plate (10) which is designed to seal the lubricant receiving chamber (12) from a dry space, in which there is no lubricant, wherein the base plate (10) has a protuberance (40) which extends into the lubricant receiving chamber (12) and defines a receptacle (42) which is open towards the dry space.

Description

[0001] Description

[0002] Lubricant pump

[0003] Technical area

[0004] The present invention relates to a pump unit for a lubricant pump according to the preamble of claim 1, as well as a method for providing such a pump unit.

[0005] Technical background

[0006] Lubrication systems for supplying mechanical components such as bearings, gears, etc. with lubricant typically include one or more lubricant pumps that transport the lubricant from a reservoir to the mechanical components. Such lubricant pumps can deliver the lubricant either to an intermediate delivery device, such as an injection nozzle, or directly to the mechanical component via hoses or fluid lines. In most lubricant pumps, the reservoir is detachably or permanently connected to a pump unit, particularly a pump housing, which contains the actual pump components.

[0007] The pump components are typically standardized assemblies used in various applications. The pump housing generally comprises at least one pump element that delivers the lubricant and a pump drive motor that drives the pump element. The pump element is usually a piston pump capable of delivering lubricant in one direction at high pressure through the translational movement of a piston and an internal valve arrangement.

[0008] Furthermore, it is necessary to determine when the lubricant reservoir is empty or the lubricant level is too low to ensure a continuous supply of lubricant to the mechanical components. A continuous supply of lubricant is also important to prevent the piston pump from taking in air and potentially damaging it.

[0009] To monitor the fill level in the reservoir, a fill level sensor is usually installed in the lubricant reservoir.

[0010] In lubricant reservoirs in which an agitator blade is used to circulate and convey the lubricant towards the pump unit, a combination of a position encoder in the form of a magnet and a position sensor in the form of a reed sensor is often used to detect the presence of lubricant in the reservoir. For this purpose, a pivoting holder is attached to the agitator blade, which can be pivoted from a first position to a second position, with the pivoting being initiated by the presence or absence of lubricant. The position encoder, in turn, is attached to the holder and is guided along a first circular path (first position) or a second circular path (second position) due to the rotation of the agitator blade. The position sensor, in turn, detects whether the position encoder is moving on the first or second circular path and outputs a corresponding signal to a control unit.

[0011] However, if a magnetic sensor is used as a position sensor and a magnet as a position encoder, it is necessary that there is a very small distance between the position sensor and the position encoder to enable reliable detection.

[0012] To achieve a short distance between the position encoder and the position sensor, the position sensor is mounted through the pump housing, which, however, requires an additional seal. Furthermore, this arrangement prevents the sensor from being replaced without draining the entire pump of lubricant, as this would leak out when removing the sensor.

[0013] It is therefore an object of the present invention to provide a lubricant pump in which the position sensor can be easily mounted and dismounted.

[0014] Summary of the invention This object is achieved by a pump unit for a lubricant pump according to claim 1.

[0015] The following describes a pump unit for a lubricant pump with a pump housing designed to be connected to a lubricant reservoir. The pump housing has a lubricant receiving chamber with at least one lubricant outlet. At least one pump element can be arranged in the lubricant receiving chamber, which is designed to convey lubricant from the lubricant reservoir via the lubricant receiving chamber to the lubricant outlet. Furthermore, the pump housing has an integrally formed base plate designed to close off the lubricant receiving chamber from a dry chamber in which no lubricant is present.

[0016] In order to enable simple assembly and disassembly of a position sensor, it is proposed that the base plate have a protrusion extending into the lubricant receiving space, which defines a receptacle open to the dry space. In principle, another element or sensor than the position sensor can be accommodated in this receptacle, but an embodiment in which the position sensor is accommodated in the receptacle is particularly preferred. The protrusion directed towards the dry space ensures that the position sensor is arranged spatially close to the lubricant reservoir, but is nevertheless arranged in the dry space of the pump unit. The receptacle open to the dry space also allows an element to be inserted into or removed from the receptacle without the lubricant pump having to be emptied.This is particularly advantageous for optimized assembly or replacement of pump components.

[0017] It is particularly preferred if the sensor is a fill level sensor that detects whether lubricant is still present in the reservoir. The fill level sensor can, for example, be implemented via a proximity switch that comprises a position sensor and a position encoder, wherein the position sensor can be arranged in the protuberance and the position encoder in the lubricant reservoir. Alternatively, a fill level sensor that functions without a counter element arranged in the lubricant reservoir can also be accommodated in the protuberance. Such a sensor can, for example, be a capacitive and / or optical and / or acoustic sensor that can directly detect the fill level of the lubricant. Furthermore, it is preferred if a rotatingly drivable impeller extending into the lubricant reservoir is provided on the pump unit, which impeller is connected, for example, to a drive shaft that drives the pump element.The impeller serves to circulate the lubricant present in the reservoir and push it toward the pump unit. This type of impeller is particularly advantageous when using grease as a lubricant, as it ensures that the viscous grease is pumped to the pump unit.

[0018] According to a further preferred embodiment, a fill level sensor, for example in the form of a proximity switch, is advantageous, which can be at least partially attached to the agitator blade. For this purpose, a sensor element can be attached to the agitator blade to determine whether lubrication is still present in the reservoir. In particular, an embodiment is preferred in which a position sensor is arranged on the agitator blade and a position sensor is arranged in the protuberance, which interact to detect the fill level.

[0019] For this purpose, it is particularly advantageous that a pivotably hinged holder for a position sensor is arranged on the agitator blade, wherein the holder is pressed into a first end position due to the flow resistance of the lubricant during the rotational movement of the agitator blade, in which first end position the position sensor rotates on a first orbit. Furthermore, a deflection device is preferably provided which transfers the holder with the position sensor from the first end position to a second end position during the rotational movement, in which second end position the position sensor rotates in a second orbit that deviates from the first orbit. The deflection unit can, for example, be a spring that preloads the holder into the second position. It is also possible for the deflection device to be arranged, for example, on a part of the pump housing or the lubricant reservoir.Particularly preferred is an embodiment in which the deflection device is formed on an intermediate plate which separates the lubricant receiving space from the reservoir interior.

[0020] A position sensor is also provided, which detects whether the position sensor is rotating on the first and / or second orbit. Since the first position or the first orbit is reached by the flow resistance of the lubricant, the position sensor can determine whether lubricant is still present in the reservoir. The monitoring principle therefore consists in sensing the position of a position sensor using a position sensor, with the position of the position sensor depending on whether or not there is still lubricant in the reservoir.

[0021] The position sensor itself can be a magnet, and the position sensor a magnetic switch, particularly a reed sensor. However, it is also possible to determine the position of the position sensor optically, capacitively, inductively, or similarly.

[0022] In all embodiments, however, it is advantageous or even necessary for the position sensor to be located as close as possible to the position encoder. In the prior art, the position sensor was therefore mounted through the pump housing or the base plate, which, however, required an additional seal between the sensor and the base plate. Furthermore, replacing the sensor required the entire lubricant pump to be emptied of lubricant, as this would leak out and become contaminated when disassembling the sensor.

[0023] The inventive protrusion of the base plate described here now allows the position sensor to be arranged spatially close to the position encoder without having to insert the position sensor into the lubricant receiving space. This also allows the use of commercially available position sensors, such as reed sensors, since no special housing or interface is required to position the sensor in the lubricant receiving space.

[0024] To minimize the shielding effect of the walls forming the protrusion, an embodiment is further advantageous in which the protrusion has a side wall and a cover wall, and the wall thickness of the cover wall of the protrusion is thinner than the wall thickness of the base plate. Especially in magnetic switches, the material of the base plate and thus also of the protrusion can influence the magnetic field of the magnet (position sensor), for example, reducing or distorting it, which can impair position measurement.

[0025] The protrusion itself is preferably adapted to the shape of the element to be accommodated in order to take up as little space as possible in the lubricant receiving chamber. For example, the protrusion can be cylindrical to accommodate a cylindrical sensor.

[0026] According to a further preferred embodiment, the pump housing further comprises an intermediate plate that delimits the lubricant receiving space on the side facing the lubricant reservoir and has at least one lubricant inlet opening, preferably a plurality of lubricant inlet openings, for transferring lubricant from the lubricant reservoir into the lubricant receiving space. Furthermore, the protuberance is shaped such that it extends at least as far as the intermediate plate. This allows an element present in the protuberance, in particular the position sensor or the fill level sensor in general, to be arranged particularly close to the reservoir, in particular to the impeller.

[0027] In order to further reduce the spatial proximity and also to ensure that the effect of an element accommodated in the protuberance, in particular the position sensor, is not shielded by the intermediate plate, it is furthermore advantageous for the intermediate plate to have a recess, and for the protuberance to be shaped such that it extends into the recess.

[0028] A particularly close spatial proximity is achieved in an advantageous embodiment in which the protuberance has a side wall and a cover wall, wherein the cover wall extends into the recess in the intermediate plate and is aligned with the intermediate plate.

[0029] According to a further preferred embodiment, the sensor, in particular the position sensor, can be mounted in the receptacle formed by the protrusion by means of a sensor holder. This allows the protrusion to be precisely adapted to the sensor's shape, and the protrusion takes up minimal space in the lubricant receiving chamber.

[0030] To ensure adequate fastening without unduly reducing the lubricant storage space, a fastener receptacle is provided on the base plate, facing the dry space. This fastener receptacle is open towards the dry space and is designed to accommodate a fastener for attaching the sensor and / or sensor holder to the base plate. This also allows the sensor to be mounted and removed from the dry space, so that even when replacing the sensor, the lubricant pump does not need to be emptied.

[0031] According to a further preferred embodiment, the sensor holder has a holding arm, preferably designed as a sensor seat, which projects from a fastening body, wherein the holding arm is preferably designed to be resilient. This enables the sensor to be mounted offset from the fastening location. As a result, for example, the sensor can be inserted into the receptacle defined by the protrusion and fastened to the fastening means receptacle formed on the base plate with the aid of the fastening body of the sensor holder, wherein the fastening receptacle and protrusion can be arranged spatially offset from one another. The resilient design enables easy insertion of the sensor into the receptacle and compensation of manufacturing tolerances. Furthermore, structurally slightly different sensors can also be used with the same holder.

[0032] According to a further preferred embodiment, the sensor holder further comprises at least one cable fixing element designed to secure a cable connecting the sensor to a control unit and / or a power supply unit to the sensor holder in a strain-relieved manner. This facilitates the installation of the sensor and ensures that the sensor can be connected to a control unit and / or a power supply unit without slipping out of position.

[0033] Further advantages and advantageous embodiments are set forth in the description, the drawings, and the claims. In particular, the combinations of features set forth in the description and the drawings are purely exemplary, so the features may also be present individually or in other combinations.

[0034] Short character description

[0035] The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the appended claims.

[0036] They show:

[0037] Fig. 1 : a schematic sectional view of a preferred embodiment of a lubricant pump

[0038] Fig. 2: a schematic detailed view of the pump unit from Fig. 1;

[0039] Fig. 3: a schematic plan view of the pump unit from Fig. 1;

[0040] Fig. 4: schematic exploded view of a preferred embodiment of a sensor holder; and

[0041] Fig. 5: schematic representation of the sensor holder from Fig. 4 in assembly.

[0042] Detailed description of the invention

[0043] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0044] Figure 1 schematically shows a sectional view through a lubricant pump 100. The lubricant pump 100 has a reservoir 2 designed to contain lubricant, and a pump unit 4 designed to deliver lubricant from the reservoir 2 to corresponding consumers. The reservoir 2 can be detachably or permanently connected to the pump unit 4. The pump unit 4 is shown in more detail in the sectional view of Figure 2.

[0045] The pump unit 4 further comprises a pump housing 6, which is designed to separate a wet area I, namely the area in which lubricant is located, from a dry area II, the area in which, for example, electronics or drive motors are located. For this purpose, the pump housing is designed as a pot-like element and has side walls 8 and a base plate 10, which define a lubricant receiving space 12 and a dry space 13. The side walls 8, in turn, can be connected directly or indirectly to the lubricant reservoir 2.

[0046] Furthermore, as can be seen from Fig. 1, a pump element 14 is arranged in the lubricant receiving chamber 12. In the illustrated embodiment, this pump element is designed as a piston pump driven by a pump drive motor (not shown), in particular an electric motor. Such a pump element 14 has a metering piston 16 with a working chamber (not shown) that is movable by means of an eccentric 18 and has a suction phase or position and a discharge phase or position. The eccentric 18 serves to convert the rotary movement of the pump drive motor into a translatory movement of the metering piston. When actuated by the eccentric 18, the piston 16 moves from the suction position to the discharge position, so that lubricant located in the working chamber 17 can be discharged from a lubricant outlet 20.By means of a return element, in the embodiment shown here a spring 22, the piston 16 is returned to its first position, while the lubricant is sucked from the lubricant receiving chamber 12 into the working chamber.

[0047] The eccentric 18 is therefore arranged in a rotationally fixed manner on a drive shaft 24, which in turn extends through a recess 26 in the base plate 10 of the pump housing into the lubricant receiving chamber 12 and further into an interior space 3 of the lubricant reservoir 2. The drive shaft 24 can directly be an output shaft of the pump drive motor.

[0048] Furthermore, Figs. 1 and 2 show that a stirring blade 28 is arranged in a rotationally fixed manner at the free end 26 of the drive shaft. This stirring blade is designed to circulate the lubricant held in the reservoir 2 and convey it toward the pump element 14. The stirring blade is preferably driven in rotation by the pump drive motor. A fill level monitoring device is provided on the stirring blade itself, which is designed to detect the fill level of the lubricant in the reservoir. For this purpose, a pivotably deflected holder 29 is attached to the stirring blade 28, which supports a position sensor 30 in the form of a magnet.

[0049] Furthermore, Fig. 2 in particular shows that the pump housing 6 together with the drive shaft 24 and the level monitoring system attached thereto is a pre-assembled unit which separates the wet area I from the dry area II.

[0050] The functionality of the fill level monitoring system is explained with the help of Fig. 3. Fig. 3 shows a top view of the agitator blade 280 with the fill level monitoring system arranged thereon. According to the illustrated embodiment, the agitator blade 28 is rotatable about a rotation axis DR, which coincides with a central axis M of the reservoir 2. The holder 29, in turn, is pivotally mounted about an axis LH. The position sensor 30 is a cylindrical magnet mounted on the holder 29 so as to be rotatable about its rotation axis DL. The bearing axis LH and the rotation axis DL are parallel to the rotation axis DR of the agitator blade 28. The holder 29 also has on its blade lying radially outside the bearing axis LH of the holder 29 a perpendicular, ie parallel to the bearing axis LH of the holder 29, resistance plate 31 which runs approximately radially in the first end position of the holder 29 shown in Fig. 3, in which the holder 29 rests against a stop 32 formed on the agitator blade 3.

[0051] When the impeller 28 rotates in the clockwise direction indicated by the arrow, the resistance plate 31 creates the greatest possible flow resistance in the lubricant of the reservoir 2, so that the holder 29 is securely held against the stop 32. In this first end position, the position sensor 30 describes an orbit UL

[0052] Located in the orbit Ul is a deflection device in the form of a control cam 33. The control cam 33 is arranged and designed such that, with each orbit, the position sensor 30 pivots, as shown by dashed lines, into a second outer orbit U2 by pivoting the holder 29 into a second end position, in which the holder 29 rests against an outer stop 34 of the agitator blade 28. For this purpose, the control cam 8 has a run-up radius on which the cylindrical magnetic position sensor 30 can roll.

[0053] At a circumferential distance in front of the control cam 33, in the second orbit U2, there is a position sensor 35, designed as a magnetic switch, for example. If there is still lubricant in the reservoir 2, after the position sensor 30 has passed the control cam 33, the holder 29 is moved back into its first end position shown in Fig. 2 due to the flow resistance, so that the position sensor 30 again rotates in the inner first orbit Ul. However, if the reservoir 2 has already been emptied to such an extent that the holder 30 with its resistance plate 31 no longer rotates in the lubricant, when the agitator blade 28 rotates, the position sensor 30 remains in the outer second orbit U2 after passing the control cam 33, so that it inevitably passes the position sensor 35. The position sensor 35 then detects that the reservoir 2 has become empty. A signal can then be transmitted to an operator via appropriate electronics.Furthermore, it can be seen from the sectional view of Figures 1 and 2 that an intermediate plate 36 is arranged on the pump housing 6, which delimits the lubricant receiving area 12 in the direction of the reservoir 2. In order to transfer lubricant evenly from the reservoir 2 into the lubricant receiving space 12 despite the intermediate plate 36, the intermediate plate 36 further has a plurality of preferably evenly distributed lubricant passage openings 37. The intermediate plate 36 also has a recess 38 through which the drive shaft 24 extends. The control cam 33 is preferably also integrally formed on this intermediate plate 36.

[0054] Furthermore, Figs. 1 and 2 show that, in order to arrange the sensor 35 as close as possible to the magnet 30, the base plate 10 has a protrusion 40 that projects into the lubricant receiving chamber 12. The protrusion 12 has a recess 42 open to the dry chamber 13, in which the sensor 35 is accommodated.

[0055] As can be seen particularly from the detailed view of Fig. 2, the protuberance 40 has a side wall 44 and a cover wall 46. Furthermore, it is shown that the wall thickness of the cover wall 46 is significantly smaller than the wall thickness of the side wall 42. This ensures that the magnetic force of the magnet 30 can be detected by the sensor 35.

[0056] Furthermore, Figs. 1 and 2 show that the protrusion 40 extends to the intermediate plate 36 and is preferably received in a recess 48 in the intermediate plate 36. As a result, the cover wall 46 is flush with the intermediate plate 36, so that the sensor 35 can be placed particularly close to the position sensor 30.

[0057] The sensor 35 itself is held by a sensor holder 50, which has a flexible arm 52, designed as a sensor holding seat 53, and a fastening body 54 for receiving a fastening means 56. The sensor holder 50 is shown enlarged in Fig. 4 (exploded view) and 5 (assembled). In order to accommodate the sensor 35 and its signal and / or power supply cable K in a strain-relieved manner, one or more cable fixing elements 58 are further provided on the sensor holder 50, into which the cable K can be inserted and / or clipped. This facilitates the installation of the sensor 35 and ensures that the sensor 35 can be connected to a control unit and / or power supply unit without slipping out of position. Furthermore, Figs. 1 and 2 show that the sensor 35 is arranged offset from its fastening location, which is formed by a fastening means receptacle 60 formed on the base plate.The fastening body 54 of the sensor holder 50 serves to accommodate a fastening means 56, which interacts with the fastening means receptacle 60. For example, a screw can be used that is screwed into the fastening means receptacle 60.

[0058] The offset mounting of the sensor 35 means that, for example, the sensor 35 can be inserted into the receptacle 42 defined by the protrusion 40 and secured to the fastening means receptacle 60 formed on the base plate 10 using the fastening body 54 of the sensor holder 50, whereby the fastening receptacle 60 and the protrusion 40 can be arranged spatially offset from one another. The resilient design of the sensor holder arm 52 enables easy insertion of the sensor 35 into the receptacle 42 and the compensation of manufacturing tolerances. Furthermore, this allows slightly different structural sensors 35 to be used with the same holder 50.

[0059] In summary, the embodiment shown here allows the use of commercially available reed sensors, as they are simply accommodated in the protrusion and secured using the sensor holder. The sensor holder also allows the sensor to be preloaded into the holder, securing its cables, and simplifying installation overall. The protrusion also eliminates the need to drill into the lubricant storage chamber, ensuring that lubricant cannot enter the dry space and damage the components housed there. Furthermore, the sensor can be replaced even after the lubricant pump has been put into operation, without having to empty the entire lubricant pump. Reference Symbol List

[0060] 100 Lubricant pump

[0061] 2 reservoirs

[0062] 4 Pump unit

[0063] 6 Pump housing

[0064] 8 Side wall

[0065] 10 Base plate

[0066] 12 Lubricant storage chamber

[0067] 14 Pump element

[0068] 16 dosing pistons

[0069] 18 eccentric

[0070] 20 Lubricant outlet

[0071] 22 spring

[0072] 24 Drive shaft

[0073] 26 recess

[0074] 28 agitator blades

[0075] 29 holders

[0076] 30 Position sensor (magnet)

[0077] 31 resistance wall

[0078] 32 stops

[0079] 33 control cams

[0080] 34 stop

[0081] 35 Sensor

[0082] 36 intermediate plate

[0083] 37 Lubricant passage opening

[0084] 38 recess

[0085] 40 protrusion

[0086] 42 recording

[0087] 44 pages

[0088] 46 Lid wall

[0089] 48 recess

[0090] 50 sensor holders

[0091] 52 Holding arm Sensor seat Fastening body Fastener Cable fixing element Fastener holder

Claims

P a t e n t a n s p r ü c h e 1. Pump unit (4) for a lubricant pump (100) with a pump housing (6) designed to be connected to a lubricant reservoir (2), wherein the pump housing (6) has a lubricant receiving space (12) with at least one lubricant outlet (20), wherein at least one pump element (14) can be arranged in the lubricant receiving space (12), which is designed to convey lubricant from the lubricant reservoir (2) via the lubricant receiving space (12) to the lubricant outlet (20), wherein the pump housing (6) further has an integrally formed base plate (10) designed to close off the lubricant receiving space (12) from a dry space in which no lubricant is present, characterized in that the base plate (10) has a protuberance (40) extending into the lubricant receiving space (12) and having a receptacle (42) open to the dry space defined.

2. Pump unit (4) according to claim 1, wherein a sensor, in particular a fill level sensor (35), is accommodated in the receptacle (42) open to the drying chamber.

3. Pump unit (4) according to claim 1 or 2, wherein the protuberance (40) has a side wall (44) and a cover wall (46), and a wall thickness of the cover wall (46) of the protuberance (40) is thinner than a wall thickness of the side wall (44) and / or the base plate (10).

4. Pump unit (4) according to claim 2 or 3, wherein the sensor (35) is designed to cooperate with an element arranged in the lubricant reservoir (2).

5. Pump unit (4) according to claim 4, wherein the pump unit (4) further comprises a pump element drive unit, in particular an electric motor, arranged in the dry space, with a drive shaft (24), wherein the drive shaft (24) extends into the lubricant receiving space (12) and interacts with the pump element (14), wherein the drive shaft (24) extends at least partially into the lubricant reservoir (2), and further comprises an agitator blade (28) arranged on the drive shaft (24), which is designed to convey lubricant towards the pump element (14) and further comprises a pivotably articulated holder (29) for a position sensor (30), which, due to a flow resistance of the lubricant received in the reservoir (2), is pressed into a first end position during the rotational movement of the agitator blade (28), in which the position sensor (30) rotates on a first orbit,wherein the position sensor (30) interacts with a sensor (35), in particular a position sensor (35), accommodated in the receptacle (42) defined by the protuberance (40).

6. Pump unit (4) according to claim 5, wherein a deflection device is further provided which transfers the holder (29) with the position sensor (30) from the first end position to a second end position during the rotational movement.

7. Pump unit (4) according to one of the preceding claims, wherein the pump housing (6) further comprises an intermediate plate (36) which delimits the lubricant receiving space (12) on the side facing the lubricant reservoir (2) and has at least one lubricant inlet opening (37), preferably a plurality of lubricant inlet openings (37), in order to transfer lubricant from the lubricant reservoir (2) into the lubricant receiving space (12), wherein the protuberance (40) extends at least as far as the intermediate plate (36).

8. Pump unit (4) according to claim 7, wherein the intermediate plate (36) has a recess (38), and the protuberance (40) is shaped such that it extends into the recess (38), wherein preferably the protuberance (40) has a side wall (44) and a cover wall (46), and the cover wall (46) extends into the recess (38) in the intermediate plate (36) and is aligned with the intermediate plate (36).

9. Pump unit (4) according to one of claims 2 to 8, wherein the sensor (35) can be fastened in the receptacle (42) by means of a sensor holder (50).

10. Pump unit (4) according to one of the preceding claims, wherein the base plate (10) has a fastening means receptacle (60) directed towards the dry space, which is open towards the dry space and is preferably designed to receive a fastening means (56) for fastening the sensor (35) and / or the sensor holder (50) to the base plate (10).

11. Pump unit (4) according to claim 9 or 10, wherein the sensor holder (50) has a holding arm (52) preferably designed as a sensor seat (53) which projects from a fastening body (54), wherein the holding arm (52) is preferably designed to be resilient.

12. Pump unit (4) according to one of claims 9 to 11, wherein the sensor holder (50) further comprises at least one cable fixing element (58) which is designed to fasten a cable connecting the sensor (35) to a control device and / or a power supply device to the sensor holder (50) in a strain-relieved manner.

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