Power motor

Abstract

The invention relates to a power motor (10), comprising: a rotor arranged on a rotor shaft rotatable about a rotor axis (11); a stator (12) surrounding the rotor radially outside; a housing (13) surrounding the stator (12) radially outside; a drive shaft which is arranged in the shaft channel (15) so as to be rotatable about a drive shaft axis (14), the rotor shaft acting on the drive shaft via a transmission on a first axial end face (A) covered by a first housing part (16), and the rotor shaft being covered by a second housing part on a second axial end face (B), the first housing part (16) forms a first chamber (17) on a first end face (A), the second housing part forms a second chamber (18) on a second end face (B), and the first chamber (17) and the second chamber (18) are each connected in a fluid-conducting manner to the shaft channel (15).

Description

Technical Field

[0001] The present invention relates to a power motor, which comprises: a rotor arranged on a rotor shaft rotatable around a rotor axis; a stator surrounding the rotor radially outside; a shell surrounding the stator radially outside; and a drive shaft, which is arranged in a shaft channel in a manner rotatable around the drive shaft axis / axis of the shaft. Background Art

[0002] During operation of the power plant, i.e. when the rotor rotates, the rotor usually pumps air from one axial end side of the rotor shaft to the other axial end side of the rotor shaft (hereinafter also referred to as side A and side B). The air flows, for example, through a gap formed between the rotor and the stator. Since the power plant is usually closed by a housing at the end side, the air cannot escape and a pressure difference is generated between the two sides, i.e. between side A and side B. Since such a pressure difference can lead to a restricted function of the power motor, it is desirable to prevent this from happening. For example, in a sealed housing, the seal can partially fail in the event of a negative pressure. As a result, for example, moisture or dirt can enter the housing.

[0003] For example, DE 10 2008 046 446 A1 discloses a pressure compensation element in the form of an invertible membrane, which is provided to connect a spatial region of a transmission with a spatial region of an electric machine in a pressure-balanced manner in a compact drive unit.

[0004] DE 10 2018 221 202 A1 relates to an electric drive unit having a sealed housing formed by two housing parts. The housing parts are connected to each other via a pressure equalization element. The pressure equalization element is intended to ensure pressure balance between the environment and the interior of the housing, thereby preventing moisture from penetrating into the housing due to a reduction in the sealing effect caused by pressure.

[0005] WO 2022 / 189091 A1 discloses a rotor of an electric motor, which has a rotor assembly fixedly mounted on a hollow rotor shaft. An axially extending channel is formed between the rotor assembly and the circumference of the rotor shaft, and the channel is supplied with fluid via an annular channel adjacent to a central chamber of the rotor shaft in a manner having a pressure balancing effect. Summary of the invention

[0006] Against this background, the object of the invention is to provide a power motor which has a pressure equalization function in the housing of the power unit without increasing the number of components to be assembled for this purpose. The housing should provide optimal protection for the components accommodated therein against external influences, such as moisture and dirt. Furthermore, the power unit should be producible at low cost.

[0007] This object is achieved by a power motor having the features of claim 1. Furthermore, particularly advantageous embodiments of the invention are disclosed in the dependent claims.

[0008] It should be noted that the features described individually in the claims can be combined with each other in any technically reasonable manner (also across category boundaries such as between methods and devices) and represent additional embodiments of the invention. The description, in particular in conjunction with the drawings, additionally represents the features of the invention and describes the invention in detail.

[0009] It should also be noted that the conjunction "and / or" used here between two features and connecting the features to one another should always be interpreted as meaning that in a first design of the subject matter according to the invention only the first feature may be present, in a second design only the second feature may be present, and in a third design both the first feature and the second feature may be present.

[0010] The subject of the present invention is a power motor, which includes: a rotor arranged on a rotor shaft rotatable around a rotor axis; a stator surrounding the rotor on the radial outside; a housing surrounding the stator on the radial outside; a drive shaft, which is arranged in a shaft channel in a manner that can rotate around the drive shaft axis. The rotor shaft acts on the drive shaft through a transmission mechanism on the first axial end side (also referred to as the A side in this article) covered by the first housing member. In other words, the rotor shaft drives the drive shaft via the transmission mechanism during the operation of the power device. On the second axial end side (also referred to as the B side in this article), the rotor shaft is covered by the second housing member. On the first axial end side (A side), the first housing member forms a first chamber using the first axial end side. On the second axial end side (B side), the second housing member forms a second chamber using the second axial end side. According to the present invention, the first chamber and the second chamber are respectively connected to the shaft channel in a fluid-guiding manner.

[0011] In a manner known per se, the rotor shaft of the power plant is rotatably supported in a housing. This also includes housing parts, such as bearing caps, which can be mounted on the housing in the manner of axial end covers or can be formed integrally with the housing. The stator is accommodated in the housing and is held by the housing. The shaft channel is essentially tubular and encloses a chamber in which the drive shaft is rotatably supported. The shaft channel is arranged transversely offset to the rotor shaft.

[0012] The first housing part can be used as a transmission housing for covering the transmission mechanism. The second housing part can be designed as a bearing cover for supporting the axial end of the rotor, but is not necessarily limited to this function. The second housing part can also be used only as a cover for the second axial end.

[0013] According to the invention, the shaft channel of the drive shaft is used as a pressure equalization channel, and no additional components (such as pressure equalization elements) are required for this purpose. A permanent pressure balance between the first chamber and the second chamber is ensured via the shaft channel, so that during operation of the power plant, i.e., when the rotor rotates, there is no pressure difference between the two chambers. During operation of the power plant, air pumped by the rotor from side A to side B (or from side B to side A) can flow back to the chamber on the opposite side via the shaft channel without hindrance.

[0014] Furthermore, the housing provides maximum protection for the components contained therein (e.g. stator, rotor, drive shaft, bearings of the rotor shaft and drive shaft, electrical connections, etc.) against external influences, such as moisture and dirt, since, in order to realize the pressure balancing function according to the invention, no structural modifications are required on the outside of the housing in comparison with conventional power plants, e.g. no pressure balancing elements, such as diaphragms, etc., need to be mounted on the outside of the housing. The invention ensures reliable and maintenance-free operation of the power plant, at least with regard to the pressure balancing function. Furthermore, the technical embodiment of the invention is cost-effective, since no additional components are required to provide the pressure balancing function.

[0015] In a preferred embodiment, the drive shaft axis is parallel to the rotor axis. This enables a short and easily producible fluid-carrying connection from the first chamber and the second chamber to the shaft channel, respectively, since the shaft channel according to this embodiment already partially or even completely spans the distance between the two chambers along the axial extension of the rotor shaft, i.e. the spacing between the A side and the B side. It should be noted that slight deviations from the exact (i.e. ideal) parallelism between the drive shaft axis and the rotor axis are to be included in the tolerance range that is considered common by a person skilled in the art. This is understood to be a tolerance range of the relevant dimensions from the ideal dimensions, with a maximum deviation of + / -20%, preferably + / -10%.

[0016] In another preferred embodiment, the first chamber and the second chamber are each connected to the shaft channel in a fluid-conducting manner by means of a hole, which is constructed in the housing wall that separates the shaft channel from the two chambers. Preferably, this design eliminates additional components for producing a fluid-conducting connection, such as pipes, hoses, etc.

[0017] Another embodiment provides that the first chamber and the second chamber are connected via a coolant channel in a liquid-guiding manner. The coolant channel is used to convey a coolant, such as oil, so that the heat generated on the rotor and / or stator is dissipated during the operation of the power device. For this purpose, the coolant circulates in a coolant circuit that usually includes a coolant storage portion through the coolant channel and is continuously conveyed to the rotor and / or stator. Here, the coolant can be collected in two chambers on the A side and the B side, and the coolant is returned to the coolant channel through a coolant discharge portion arranged in the chamber. The two chambers on the A side and the B side are connected by a coolant channel and a coolant container in a fluid-guiding manner. The coolant channel is permanently filled with coolant, so that when there is a pressure difference between the two chambers, different coolant levels inevitably appear on the A side and the B side. In the absence of pressure balance according to the present invention, even if the pressure difference is small, the liquid level of the coolant in the chambers on the A side and the B side may also change strongly, so that the rotor gap formed between the rotor and the stator can be flooded by the coolant, which leads to obvious efficiency loss. However, the permanent pressure equalization between the A-side and B-side chambers produced according to the invention via the shaft channel prevents such an efficiency-impairing operating state of the power plant.

[0018] According to another preferred embodiment, the first chamber and the second chamber are designed to each accommodate a certain amount of coolant up to a predeterminable maximum coolant level, wherein the opening for the fluid-conducting connection of the shaft channel is arranged above the respective maximum coolant level. This ensures that the pressure equalization channel provided by the shaft channel remains dry, since it cannot be flooded with coolant. The fluid-conducting connection between the chambers on the A side and the B side via the shaft channel is therefore only an air-conducting connection.

[0019] In another preferred embodiment, the first housing part and the second housing part can be fixed to the housing in a non-destructively releasable manner. This simplifies the maintenance of the power plant, such as the rotor shaft, transmission mechanism, bearings, electrical connections, etc. In addition, the fluid-conducting connections of the chambers to the shaft channel can be easily checked and, if necessary, cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features and advantages of the present invention are given by the following description, which does not limit the embodiments of the present invention, and will be described in more detail below with reference to the accompanying drawings. In the accompanying drawings:

[0021] Figure 1 A perspective partial view of an axial end side of a power device according to one embodiment of the invention is shown;

[0022] Figure 2 Show Figure 1 a partially cut-away side view of a power plant in; and

[0023] Figure 3 Show Figure 1 A perspective and partially cutaway partial view of the opposite axial end sides of the power unit in FIG. DETAILED DESCRIPTION

[0024] In the various figures, components with the same function are always provided with the same reference symbols, so that these components are usually also described only once.

[0025] In the following description, reference is made to Figures 1 to 3 . Figure 1 A perspective partial view of an axial end side B of a power plant 10 according to one specific embodiment of the invention is schematically shown. Figure 2 Show Figure 1 A partially cut-away side view of the power device 10 in FIG. Figure 3 Show Figure 1 A perspective and partially cutaway partial view of the opposite axial end side A of the power unit 10 in FIG.

[0026] The power plant 10 has a rotor (not shown) arranged on a rotor shaft (not shown) rotatable about a rotor axis 11, a stator 12 radially surrounding the rotor on the outside, a housing 13 radially surrounding the stator 12 on the outside, and a drive shaft (not shown) arranged in a shaft channel 15 rotatable about a drive shaft axis 14. The rotor shaft acts on the drive shaft via a transmission mechanism (not shown) on a first axial end side A (also referred to as the A side in this document) covered by a first housing part 16. On a second axial end side B (also referred to as the B side in this document), the rotor shaft is covered by a second housing part (also not shown). On the first end side A, the first housing part 16 forms a first chamber 17 with the axial end side A. On the second end side B, the second housing part forms a second chamber 18 with the axial end side B.

[0027] The first chamber 17 and the second chamber 18 are each connected to the shaft channel 15 in a fluid-conducting manner. For this purpose, corresponding holes 19 are formed in the housing wall that separates the shaft channel 15 from the two chambers 17, 18, in the present case the chamber 17 on the first A side and the chamber 18 on the second B side. The holes 19 are respectively arranged above the maximum coolant level (not shown) in the corresponding chambers 17 and 18, because in the present embodiment, the chambers are designed to accommodate a certain amount of coolant, not shown, respectively. The coolant enters the first chamber 17 and the second chamber 18 via a coolant channel, also not shown, and is used to cool the rotor and / or the stator 12 during operation of the power device 10.

[0028] During operation of the power plant 10, air pumped by the rotor from side A to side B (or vice versa) can flow unimpeded back to the chamber on the opposite side via the shaft passage 15. This air flow, for example, Figures 1 to 3 This is indicated by flow arrows 21 .

[0029] In a generally known manner, the rotor shaft of the power plant 10 is rotatably supported in the housing 13. For this purpose, the power plant 10 has corresponding bearing seats 20 on the A side and the B side for accommodating rotor shaft bearings (not shown). Likewise, the drive shaft is rotatably supported in the shaft channel, wherein corresponding bearings (also not shown) are accommodated in corresponding bearing seats 20 of the shaft channel.

[0030] exist Figure 1 It can be seen in FIG. 1 that the drive shaft axis 14 of the power plant 10 shown here is parallel to the rotor axis 11 .

[0031] Furthermore, the first housing part 16 and the second housing part can be fixed to the housing 13 in a non-destructively detachable manner. For this purpose, the housing 13 has corresponding threaded holes on the A side and the B side, by means of which the two housing parts can be screwed to the housing 13 respectively.

[0032] Furthermore, electrical connections 22 for energizing the stator 12 are arranged in the B-side chamber 18 .

[0033] List of reference numerals:

[0034] 10 Power Motor

[0035] 11 Rotor axis

[0036] 12 Stator

[0037] 13 Housing

[0038] 14 Drive shaft axis

[0039] 15 axis channels

[0040] 16 first housing member

[0041] 17 First Chamber

[0042] 18 Second Chamber

[0043] 19 holes

[0044] 20 Bearing seat

[0045] 21 Air Flow

[0046] 22 Electrical connection terminals

[0047] A First axial end side

[0048] B Second axial end side

Claims

1. A power motor (10), comprising: - a rotor arranged on a rotor shaft rotatable about a rotor axis (11), - a stator (12) surrounding the rotor radially on the outside, - a housing (13) surrounding the stator (12) radially on the outside, and a drive shaft which is arranged in the shaft channel (15) so as to be rotatable about the drive shaft axis (14), It is characterized in that The rotor shaft acts on the drive shaft via a transmission mechanism at a first axial end side (A) covered by a first housing part (16), and at a second axial end side (B), the rotor shaft is covered by a second housing part, wherein the first housing part (16) forms a first chamber (17) with the first axial end side (A), and the second housing part forms a second chamber (18) with the second axial end side (B), wherein the first chamber (17) and the second chamber (18) are respectively connected to the shaft channel (15) in a fluid-conducting manner.

2. The power motor according to claim 1, characterized in that: The drive shaft axis (14) is parallel to the rotor axis (11).

3. The power motor according to claim 1 or 2, characterized in that: The first chamber (17) and the second chamber (18) are each connected to the shaft channel (15) in a fluid-conducting manner by means of a bore (19) which is formed in a housing wall which separates the shaft channel (15) from the two chambers (17, 19).

4. A power motor according to any one of the preceding claims, characterized in that: The first chamber (17) and the second chamber (18) are connected in a liquid-conducting manner via a coolant channel.

5. The power motor according to claims 3 and 4, characterized in that: The first chamber (17) and the second chamber (18) are designed to respectively accommodate a certain amount of coolant up to a predeterminable maximum coolant filling level, wherein the opening (19) is respectively arranged above the respective maximum coolant filling level.

6. A power motor according to any one of the preceding claims, characterized in that: The first housing part (16) and the second housing part can be fixed to the housing (13) in a manner that allows them to be detached without causing damage.

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