Patent Publication Number: US-2021180609-A1

Title: Pump, in particularly for a fluid circuit in a vehicle

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2019/076589, which was filed on Oct. 1, 2019, and which claims priority to German Patent Application No. 10 2018 125 031.2, which was filed in Germany on Oct. 10, 2018 and which are both herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a pump, in particular for a fluid circuit in a vehicle, for example a coolant pump. 
     Description of the Background Art 
     A pump is known from document DE 10 2011 055 599 A1. The latter has a multi-part housing with a pump chamber, a motor chamber and an electronics chamber. An impeller is arranged in the pump chamber and is driven by a motor which is arranged in the motor chamber. An electrical circuit with which the motor can be controlled and/or regulated is provided in the electronics chamber. 
     The flow of fluid conveyed by a pump can also be used to cool the pump. For this purpose, a part of the fluid flow can be branched off, which is guided to areas of the pump in which heat accumulates, which is carried away by means of the branched fluid circuit. In the case of a pump, as disclosed in document DE 10 2011 055 599 A1, the heat can arise in particular in the motor and in the electronic circuit. So that the heat arising in the motor and the circuit is removed, the branched fluid circuit can preferably be guided through the engine and as close as possible past the circuit. The branched fluid flow can then, for example, be guided through the motor chamber in which a rotor is rotatably disposed. The fluid flow can circulate around the rotor. By the rotation of the rotor in the operation of the pump, the fluid in the motor chamber is also set in rotation. 
     Due to the rotation of the fluid in the motor chamber, stratification of the fluid in the branched stream and particles or glass bubbles carried by the fluid can occur. Gas bubbles can collect in the center or near the center of the rotating fluid and particles can thereby collect in an outer area. The gas bubbles in particular can restrict the transport of heat away from the motor or away from the circuit. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to improve the cooling of the motor and the circuit. 
     This object is achieved in that the rotor has through holes which interconnect a space of the motor chamber on a first side of the rotor and a space of the motor chamber on a second side of the rotor. The through holes can in particular be provided in an area of the rotor outside the rotor shaft. The through holes can be provided in the rotor body and not in the rotor shaft. 
     The rotor of an inventive pump can have a bush which is provided between the rotor shaft and the rotor body. The bush can be made of metal. This bush can have a through hole in which the rotor shaft is arranged. The rotor body can have a through hole in which the bush is arranged. 
     The through holes which interconnect the space of the motor chamber on the first side of the rotor and the space of the motor chamber on the second side of the rotor can be provided in the bush. 
     It is possible that the through holes which interconnect the space of the motor chamber on the first side of the rotor and the space of the motor chamber on the second side of the rotor are at least partially bounded by the rotor shaft. 
     It is possible that, for example in the wall of the through hole of the bush which accommodates the rotor shaft, or in the wall of the through hole of the rotor body which accommodates the bush, or in an outer wall of the bush, grooves are provided, and the walls of the grooves and the rotor shaft, the bush and/or the rotor body bound the through holes which interconnect the space of the motor chamber on the first side of the rotor and the space of the motor chamber on the second side of the rotor. 
     The housing of the inventive pump may comprise an annular chamber that surrounds the stator. The stator can thus lie between the motor chamber and the annular chamber. 
     A fluid connection can exist between the pump chamber, in particular a high-pressure side of the pump chamber, and the annular chamber. Via said connection, a fluid flow for cooling the motor and/or the circuit can be branched off from the pump chamber. 
     A fluid connection can also exist between the annular chamber and the space of the motor chamber on the first side of the rotor. Via said connection, the fluid flow for cooling the engine and/or the circuit can be further guided into the motor chamber, namely to the first side of the rotor. 
     The flow of fluid for cooling the motor and/or the circuit can be guided from the first side of the rotor to the second side of the rotor via the first through holes in the rotor. 
     A fluid connection can also exist between the space of the motor chamber on the second side of the rotor and the pump chamber, in particular a low-pressure side of the pump chamber. The fluid connection can take place through grooves in a through hole through which the rotor shaft is guided. 
     Via the fluid connection between the space of the motor chamber on the second side of the rotor and the pump chamber, a flow path can result from the pump chamber, in particular the high-pressure side of the pump chamber, via the annular chamber and the motor chamber back to the pump chamber, in particular to the low-pressure side of the pump chamber, via which connection a fluid flow for cooling the motor and/or the circuit can be conveyed. 
     The housing of an inventive pump may have an electronics chamber, wherein the electrical circuit is provided in the electronics chamber with which the motor can be supplied with electrical power, controlled and/or regulated. The electronics chamber can have a wall that separates the motor chamber from the electronics chamber, wherein the wall has a wall side which bounds the electronics chamber and on which an interconnect device for the electrical circuit rests flat. The flat contact can provide a particularly good transfer of the heat generated in the electronic circuit via the interconnect device into the wall, and from the wall into the fluid in the motor chamber. The heat transfer can be improved by adhesives or thermal pastes, which can, for example, fill a gap between the interconnect device and the wall. Preferably, half or even better ⅔ or more of the interconnect device rests flat against the wall between the motor chamber and the electronics chamber. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  is a perspective view of an exemplary first pump, 
         FIG. 2  is an exploded perspective view of the first pump, 
         FIG. 3  is a longitudinal section through the first pump, 
         FIG. 4  is a longitudinal section through the first pump in an exploded view, 
         FIG. 5  is a longitudinal section through an exemplary second pump, 
         FIG. 6  is a cross section through the second inventive pump, 
         FIG. 7  is a longitudinal section through an exemplary third pump, 
         FIG. 8  is a longitudinal section through an exemplary fourth pump, 
         FIG. 9  is a perspective view of a pump housing; and 
         FIG. 10  is a cross section through one of the four illustrated pumps 
     
    
    
     DETAILED DESCRIPTION 
     An The inventive pumps illustrated in the figures are very similar and are only different in a few parts, or even only in one part. Thus, with reference to  FIGS. 1 to 4 and 9 and 10 , first the first pump illustrated according to the invention is described prior to discussing the differences between the second, third and fourth inventive pumps. 
     The first pump has a multi-part housing which has a pump housing  10 , a motor housing  20 , an electronics housing  30  and a cover  40 , wherein a stator  50  of a motor of the pump is provided in the electronics housing  30 . The motor of the pump is completed by a rotor  60  which is rotatably mounted to the motor housing  20  and dips into the stator  50 . The stator  50  in turn dips into the motor housing  20 . Furthermore, an interconnect device  70  is provided, on which an electronic circuit  80  is provided, via which the motor is supplied with electrical energy and is controlled. An electronics chamber E, in which the interconnect device  70  and the circuit  80  are arranged, is bounded by the electronics housing  30  and the cover  40  of the housing. 
     The housing parts can be made of plastic, for example Vyncolit. The stator  50  is molded in the electronics housing  30 , preferably in a skirt  301  of the electronics housing  30 . 
     The pump housing  10 , the electronics housing  30  and the cover  40  each have a flange  101 ,  302 ,  401 . The motor housing  20  has two flanges  201 ,  202 , namely a first on the side facing the pump housing  10  and a second on the side facing the electronics housing  30  and the cover  40 . By screws  100  passing through the flange  101  of the pump housing  10  into the first flange  201  of the motor housing  20 , the pump housing  10  and the motor housing  20  are interconnected. By screws  110  passing through the flange  401  of the cover  40  and the electronics housing  30  into the second flange  202  of the motor housing  20 , the cover  40  and the electronics housing  30  and the electronics housing  30  and the motor housing  20  are interconnected. 
     To achieve a more pressure-resistant connection between the pump housing  10  and the motor housing  20 , the flange  101  of the pump housing  10  has a circumferential web  102  which positively engages in an annular groove  203  that is provided in the first flange  201  of the motor housing. As a result, an expansion of the pump housing  10  and of the motor housing  20  during operation of the pump due to the pressure prevailing there can be avoided or at least reduced. 
     The pump has an impeller  90  which is rotatably mounted in the pump housing  10  and which for that purpose is mounted on a shaft  601  of the rotor  60 , which shaft protrudes into in the pump housing  10 . 
     The pump housing  10  and a wall  204  of the motor housing, namely the wall that is protruded by the motor shaft  601 , encloses a pump chamber P in which the impeller  90  is disposed. The pump chamber P can be connected via an intake port  103  of the pump housing  10  to a line through which the fluid to be pumped is suctioned in. The intake port  103  is arranged coaxially to an axis of rotation of the rotor  60 . 
     The pump chamber P can be connected via an outlet port  104  to a line into which the pumped fluid is pressed. An outer wall of the pump housing  10  and the impeller  90  define a spiral space S which spirally expands towards the outlet of the pump chamber. The impeller  90  is formed in a known per se, for example as illustrated in the document DE 10 2011 055 599 A1,  FIG. 2, 3 or 5 , in which for purposes of a more detailed explanation, an impeller  90  which can be used for an inventive pump is referenced. 
     The impeller  90  has a bush, preferably made of metal, with a center through hole into which the rotor shaft  601  is inserted so that the impeller  90  with the bush  901  is seated on the rotor shaft  601  in a torque-proof manner, preferably with a press fit. Parallel to the center through hole of the bush  901 , the bush has one or more grooves  902  which, together with the rotor shaft  601 , form through holes through which a fluid can flow from a side of the impeller  90  facing the motor housing  20  to a side of the impeller  90  facing the intake. In the example shown, there are three grooves  902 . 
     To the extent of which the spiral space S of the pump chamber P widens spirally, the wall of the pump housing  10  radially limiting the pump chamber P tapers off. In this wall, there are recesses  105  which are open in the direction of the motor housing  20 . In the examples shown in the figures, these recesses  105  are approximately the shape of a straight cylinder with a base area that resembles the sector of a circular ring. The base area of the cylinder in the examples shown is therefore similar to a sector of an annular ring because the inner walls of the recesses  105  follow the spiral shape of the radial bounding of the pump chamber P or the spiral space S of the pump chamber P. This results in recesses  105  tapering in the circumferential direction. Also resulting from this is that the recesses  105  differ. 
     Complementary to the recesses  105 , protrusions  205  are provided on the wall  204  facing the pump housing  20  through which the rotor shaft  601  extends, which protrude into the recesses  105  when the pump is assembled. 
     Due to the recesses  105  and the complementary protrusions  205 , the pump housing  10  and the motor housing  20  can only be assembled in one specific position when the pumps are installed. 
     A specific position of the pump housing  10  and the motor housing  20  could also be achieved in other ways. 
     The recesses  105  and protrusions  205  also have another effect. The area of the pump housing  10  and the motor housing  20 , in which the recesses  105  or the protrusions are provided  205 , separates the high-pressure area and the low-pressure area of the pump chamber P and of the spiral space S. These must be well sealed off against each other so that a fluid flow on the fluid circuit past the lines connected to the pump is prevented as much as possible, and the pump can operate as effectively as possible. If the protrusions  205  and the recesses  105  were not provided, instead, flat surfaces of the pump housing  10  and the motor housing  20  would lie next to each other. The protrusions  205  and recesses  105 , however, create a kind of labyrinth seal which, even without an additional seal, provide an improved seal between the high-pressure area and the low-pressure area. 
     In the already mentioned wall  204  through which the rotor shaft  601  protrudes, a bush  206  is formed, which serves as a bearing for the rotor shaft  601 . It is also possible that a bush  206  for mounting the rotor shaft is inserted in the aforementioned wall  204  and is firmly connected to the rest of the motor housing  20 . The bush  206  has a through hole whose cross section is fitted to the rotor shaft  601 . Axially in the wall of the through hole, one or more, preferably two grooves  207  (not visible in  FIG. 3 ) are provided through which, when the rotor shaft  601  is inserted, a fluid can flow between the pump chamber P and a motor chamber M bounded by the motor housing  20  and the skirt  301  and vice versa. Small amounts of the fluid conveyed through the grooves  207  are carried along by the shaft  601  at a rotation of the rotor and provide for a lubrication between the rotor shaft  601  and the bush  206 . 
     In the wall  204 , which is penetrated by the rotor shaft  601 , one or more through holes  208  are provided in the area of the spiral space S—in the illustrated examples, there are three through holes  208 —which create a connection between the spiral space S and an annular chamber R bounded by the motor housing  20 , the skirt  301  and an end wall  303  of the electronics housing  30 . A fluid can be conveyed into the annular chamber R through the through holes  208  from the spiral space, which is located on the high-pressure side of the impeller  90 . 
     The annular chamber R is connected to the motor chamber M by one or more radial through holes  304  in the skirt  301 . The through holes  304  are provided in the vicinity of the end wall  303 . A fluid which crosses from the annular chamber R into in the motor chamber M can be conveyed through the motor chamber M, for example through a gap between the rotor  60  and the skirt  301  to the side of the motor chamber M facing the rotor  60  of the pump chamber P. By the aforementioned grooves in the bush  206  of the rotor shaft  601  and the grooves  902  in the bush  901  of the impeller  90 , the fluid can be conveyed to the intake side of the impeller  90 , that is to say to the low-pressure side of the impeller  90 . Thus, there is a continuous connection between the spiral space S, i.e. the high-pressure side of the pump chamber P, through the through holes  208  between the spiral space S and the annular chamber R into the annular chamber R, and from there, through the through holes  304  between the annular chamber R and the motor chamber M into the motor chamber M, from the motor chamber M via the grooves  207  in the bearing bush  206  and the grooves  902  in the bush  901  of the impeller  90  to the intake side of the impeller  90 , of the low-pressure side of the pump chamber P. When the pump is operating, a flow of fluid is created along this path, which is definitively smaller than the flow conveyed by the pump to the outlet, but is so large that it can achieve adequate cooling of the pump at a rated operation. 
     When cooling the pump by means of a fluid flow along the described flow path, in particular in a space between the rotor  60  and the end wall  303  of the electronics housing  30 , air may accumulate which is located in the fluid circuit, for whatever reason. The air collected in this space can hardly escape from this room or be pushed out of this room. When the pump is operating, both the fluid and the air in this space are set in rotation due to the movement of the rotor. The resulting centrifugal forces lead to a stratification in this space corresponding to the density of the media accumulated there. As a result, the air accumulates in the center of the room, while the fluid collects in the outer region and can be further conveyed from there through the annular gap between stator  50  and rotor  60 . 
     The accumulation of air has disadvantages for the cooling of the pump, in particular for the cooling of the rotor  60  and the electronics circuit  80 . 
     This can be remedied if the shaft  601  of the rotor  60  is provided with a central bore. This could stretch over the entire length of the shaft  60  and thus connect the space between the rotor  60  and the end wall  303  of the electronics housing with the low-pressure side of the pump chamber P. It is also possible that the central bore extends only from the end of the shaft  601  facing this space to the other side of the rotor  60 . Via these longitudinal bores and transverse bores in the rotor shaft  601 , air can then be transported from one side of the rotor  60  to the other side of the rotor. The air can take its further, already described path via the grooves  306  in the bearing bush for the rotor, to be guided to the low-pressure side of the pump chamber P. 
     Transporting the air through a central bore of the shaft  601  makes it necessary to produce the central bore and possibly the transverse bore, which is costly. Moreover, it must be taken into account that other properties of the shaft arise from the bores as compared to a shaft  601  made of solid material. This consideration of the other properties of the shaft can result in additional cost. 
     In the first to fourth pump in the figures, different variants are therefore selected. 
     In the first pump, in an area of the rotor between the shaft and the permanent magnet, first through holes  603  and second through holes  604  are provided. The first through holes  603  extend parallel to the shaft  601  in an area immediately adjacent to the shaft  601 . The second through holes  603  are radially further away from the rotor shaft  601  and thus closer to the permanent magnet  607 . Both through holes connect a space of the motor chamber on a first side of the rotor and a space of the motor chamber on a second side of the rotor. 
     The first through holes  603  have the advantage that they begin more in the center of rotation and thus also more in the center of the accumulating air. This can ensure that no large air bubble forms. However, the first through holes  603  have the disadvantage that the rotor body  602 , which encloses the permanent magnet  607  and through which the rotor shaft  601  is guided, is weakened by means of the first through holes  603  in an area in which there is little material available. This leads to low wall thicknesses of the rotor body  602  in the area of the first through holes  603 , which must be given special consideration. The rotor body  602  is preferably made of plastic. 
     The second through holes  604  are surrounded by more material, which has structural advantages over the first through holes  603 . However, the air cannot be discharged as well through the second through holes  604  as through the first through holes  603 . 
     It is possible that in pumps according to the invention, the first and second through holes  603 ,  604 , as shown for the first pump according to the invention ( FIGS. 3 and 4 ) and the fourth pump according to the invention ( FIG. 8 ), only the first through holes  603 , as shown for the second pump according to the invention ( FIGS. 5 and 6 ), or only the second through holes  604  are provided. 
     The first and fourth pumps differ, among other things, by the rotor shaft  601 . While the second pump has a smooth, circular cylindrical shaft  601 , the rotor shaft  601  of the fourth pump has constrictions and shoulders, which cause an improved connection between the shaft and the rotor body  602 , which envelops the permanent magnet  607 . 
     The third pump presents a different solution for through holes for venting the space between rotor  60  and end wall  303  of the electronics housing  30 . For this solution, a bush  605  is provided between the rotor body  602  and the shaft  601 , which corresponds to the bush  901  of the impeller  90  and is preferably identical to the bush  901  of the impeller  90 . The shaft  601  is smooth and circularly cylindrical. By using identical bushes  605 ,  901  for the impeller  90  and the rotor  60 , i.e. by using identical parts, several advantages can be achieved. The rotor  60 , as also the impeller  90 , has grooves  902 ,  606  that are provided for the coolant flow which are guided close to the rotor shaft  601 . This offers the possibility of improved ventilation for the coolant flow through the rotor  60  without the shaft  601  having to be specially designed for this purpose. The grooves allow for through holes, which are guided very close to the axis of rotation, without the need for the rotor body  602  enveloping the permanent magnet  604  to be weakened in an area in which little material is available. 
     An advantageous feature of the fourth inventive pump, which can also be provided in all other pumps according to the invention, is that the side of the end wall  303  of the electronics housing  30  facing away from the motor chamber M is flat. This makes it possible for the interconnect device  70  carrying the electronic circuit  80  to lie flat against this side of the end wall  303 . Preferably, the interconnect device  70  can be glued to this side of the end wall  303 , preferably with an adhesive that conducts heat in a special way and thus transports circulated fluid from the circuit  80  or the interconnect device  70  on the one side via the end wall  303  into the motor chamber M. Fastening by other means could then be omitted. If a detachable fastening of the interconnect device in the electronics housing is preferred, this can be carried out via a detachable fastenor. In order to still achieve a good heat transfer from the interconnect device  70  into the end wall  303 , a thermal paste can be provided between the interconnect device  70  and the end wall  303 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.