Abstract
A pump for delivering a liquid, having an electric motor with a stator and a rotor arranged inside the stator. The electric motor is accommodated in an electric motor housing. The stator has two end faces and an outer peripheral surface and there is formed between the electric motor housing and the outer peripheral surface of the stator an outer fluid channel through which the liquid can be delivered. The stator has on at least one of its end faces a connection to the electric motor housing.
Claims
1. A pump for delivering a liquid, comprising: an electric motor, comprising: a stator having two end faces and an outer peripheral surface; and and a rotor arranged inside the stator; an electric motor housing in which the electric motor is accommodated; and an outer fluid channel formed between the electric motor housing and the outer peripheral surface of the stator through which the liquid can be delivered; wherein the stator has on at least one of its end faces a connection to the electric motor housing.
2. The pump as claimed in claim 1, wherein the connection of the stator to the electric motor housing is arranged spaced apart from the outer fluid channel.
3. The pump as claimed in claim 1, wherein the connection of the stator to the electric motor housing is arranged spaced apart from the outer peripheral surface.
4. The pump as claimed in claim 1, wherein the electric motor housing is arranged spaced apart from an outer peripheral surface of the stator.
5. The pump as claimed in claim 1, wherein the outer fluid channel is defined by the outer peripheral surface of the stator and the electric motor housing.
6. The pump as claimed in claim 1, wherein the outer peripheral surface of the stator is formed by a plastics overmold of the stator.
7. The pump as claimed in claim 1, wherein an inner fluid channel is formed between the stator and the rotor through which the liquid can be delivered.
8. The pump as claimed in claim 1, wherein the outer fluid channel is an annular passage.
9. The pump as claimed in claim 8, wherein the annular passage extends over at least 80% of a length of extension of the stator.
10. The pump as claimed in claim 1, wherein the pump is configured as one of a fuel pump, an oil pump, or a coolant pump.
11. The pump as claimed in claim 9, wherein the annular passage extends over an entire length of extension of the stator.
12. A motor vehicle comprising: at least one pump for delivering a liquid, comprising: an electric motor, comprising: a stator having two end faces and an outer peripheral surface; and a rotor arranged inside the stator; an electric motor housing in which the electric motor is accommodated; an outer fluid channel formed between the electric motor housing and the outer peripheral surface of the stator through which the liquid can be delivered; wherein the stator has on at least one of its end faces a connection to the electric motor housing.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The invention will be explained in detail below on the basis of an exemplary embodiment and with reference to the drawings. In the drawings:
[0029] FIG. 1 is a sectional view of a pump; and
[0030] FIG. 2 is another sectional view of the pump from FIG. 1.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0031] FIG. 1 shows a sectional view of a pump 1 according to one aspect of the invention, which is in the form of a fuel pump. The pump 1 has a pump stage 2 and an electric motor 3. The pump stage 2 comprises a pump stage housing 4, which has an intake region 6 through which a liquid to be delivered, in this case fuel, can be drawn by suction from a tank. A first spindle 5 and a second spindle 5′ are accommodated in the pump stage housing 4. The first spindle 5 is in drive connection by way of a coupling 17 with a shaft of a rotor 12 of the electric motor 3 and can thus be driven by the electric motor 3. The second spindle 5′ can be driven by the rotation of the first spindle 5. The rotor 12 is rotatably arranged inside the stator 11 of the electric motor 3. The shaft of the rotor 12 is rotatably mounted in a first rotor shaft bearing 13 and a second rotor shaft bearing 14. The second rotor shaft bearing 14 is formed in one piece with an end cap 16, which has a fluid outlet 20 in the form of a connecting piece. Furthermore, the end cap has been produced from plastics material in a single plastics injection molding process. The first rotor shaft bearing 13 has likewise been produced from plastics material by plastics injection molding. The first rotor shaft bearing 13 is additionally integrated in a holder 15. The holder 15 is arranged between the pump stage housing 4 and the stator 11, which has a plastics overmold 11′. Furthermore, the holder 15 has three supporting arms supported on the pump stage housing 4. The three supporting arms extend from the first rotor shaft bearing 13 in the direction towards the pump stage housing 4 and are thereby offset by 120° relative to one another in the peripheral direction, that is to say in the peripheral direction based on the axis of rotation of the rotor 12, so that a liquid to be delivered, in this case fuel, can be delivered from the pump stage housing 4 to an outer fluid channel 18. The outer fluid channel 18 extends over the entire length of extension of the stator 11 substantially parallel to the axis of rotation of the rotor 12 of the electric motor 3. The outer fluid channel 18 is thereby defined by the plastics overmold 11′ of the stator 11 and an electric motor housing 7, which is in the form of a sheet-metal jacket. The electric motor housing 7 in the form of a sheet-metal jacket extends from a first body edge 8, which belongs to the pump stage housing 4, to a second body edge 8′, which belongs to the end cap. The electric motor housing 7 engages behind both the first body edge 8 and the second body edge 8′, such that the pump stage housing 4 and the end cap 16 are biased against one another. Because the stator 11 on the one hand is supported by its plastics overmold 11′ on the end cap 16 and on the other hand is supported on the holder 15, wherein the holder 15 is in turn supported on the pump housing 4, the electric motor 3 is fixed in a statically determinate manner inside the pump 1 in that the stator 11 is clamped between the pump housing 4 and the end cap 16. In other words, the connection or fastening of the stator 11 to the electric motor housing 7 is effected in this exemplary embodiment by clamping of the stator 11 between the pump stage housing 4 and the end cap 16. Furthermore, the pump housing 4 has in the vicinity of the first body edge 8 a sealing element 9, which is in the form of an O-ring. In addition, the end cap 16 has in the vicinity of the second body edge 8′ a second sealing element 9′, which likewise is in the form of an O-ring. A leakage flow from the electric motor housing 7 is prevented by the two sealing elements 9, 9′. Between the holding element 15 and the pump stage housing 4 there are provided centering pins 10 for orienting the holding element 15 in a defined manner relative to the pump housing 4. In addition, there is provided between the rotor 12 and the stator 11, which has a stator winding 21, an inner fluid channel 19, the flow cross-section of which is many times smaller than that of the outer fluid channel 18. Cooling of the rotor 12 and also of the stator winding 21 of the stator 11 is ensured with the aid of the inner fluid channel 19. During delivery operation of the pump 1, the fuel to be delivered passes through the intake opening 6 into the pump stage housing 4, where it is delivered in the direction towards the electric motor 3 by the rotation of the two spindles 5, 5′. From there, the delivery stream splits into two partial delivery streams, of which a first partial delivery stream flows between the 3 supporting arms to the outer fluid channel 18 and along the electric motor housing 7 and along the stator 11 to the fluid outlet 20. The second partial delivery stream flows through openings in the holder 15 past the first rotor shaft bearing 13 into the inner fluid channel 19. From the inner fluid channel 19, the second partial delivery stream flows in the direction towards the end cap 16 to the fluid outlet 20. In other words, the two partial delivery streams come together again in the region of the end cap 16 and leave the pump 1 together from the fluid outlet 20. The fluid outlet 20 is in the form of a connecting piece to which a fluid line can be connected. FIG. 1 furthermore has a cutting line A-A.
[0032] FIG. 2 shows the sectional view of the cutting line A-A through the electric motor 3 of the pump from FIG. 1. It can be seen that the electric motor housing 7 and the plastics overmold 11′ of the stator 11 define the outer fluid channel 18 in the radial direction, that is to say perpendicular to the axis of rotation of the rotor 12. Furthermore, the outer fluid channel 18 is in the form of an annular passage 18, which extends through 360° around the axis of rotation of the rotor shaft 12 and has a constant annular passage height. Uniform distribution of the first partial delivery stream, which can be delivered through the outer fluid channel 18, is thereby achieved, which results in uniform cooling of the stator and a low flow resistance. Furthermore, the stator winding 21, which is in the form of a concentrated winding, can be seen in FIG. 2. The stator winding 21 and the rotor 12 are cooled by the second partial delivery stream, which can be delivered through the inner fluid channel 19.
[0033] The exemplary embodiment of FIGS. 1 and 2 in particular does not have a restrictive character and serves merely for illustrating the concept of the invention.
[0034] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
