JP7574644B2 - pump - Google Patents

Description

The present invention relates to a pump.

Pumps are known that include a housing having a pump chamber that houses a pump mechanism therein and an intake passage that is connected to the pump chamber. For example, Patent Document 1 describes an internal gear pump as such a pump.

Patent No. 6526371

In pumps such as those described above, the intake passage may have a bent portion. In this case, pressure loss may occur in the fluid at the bent portion of the intake passage, making it difficult for the fluid in the intake passage to flow into the pump chamber. This may reduce the amount of fluid drawn into the pump chamber from the intake passage, reducing the pump efficiency.

In view of the above circumstances, one of the objects of the present invention is to provide a pump having a structure that can suppress a decrease in the amount of fluid drawn into the pump chamber from the suction flow path.

One embodiment of the pump of the present invention comprises a motor having a shaft rotatable about a central axis extending in the axial direction, a pump mechanism connected to the shaft, and a housing that accommodates the motor and the pump mechanism. The housing has a pump chamber that accommodates the pump mechanism, and an intake flow path that is connected to the pump chamber. The intake flow path has a first flow path portion that extends in the axial direction, and a second flow path portion that bends and extends from the first flow path portion and connects to the pump chamber. When viewed in the axial direction, the width of the second flow path portion increases toward the pump chamber.

According to one aspect of the present invention, in a pump, it is possible to suppress a decrease in the amount of fluid drawn into the pump chamber from the suction flow path.

FIG. 1 is a cross-sectional view showing a pump according to an embodiment. FIG. 2 is a cross-sectional view showing a part of the pump of the embodiment, taken along line II-II in FIG.

In the following description, the direction in which the Z axis in each figure extends is the up-down direction, the side in which the Z axis arrow points (+Z side) is called the "upper side," and the opposite side to the side in which the Z axis arrow points (-Z side) is called the "lower side." The central axis J1 in each figure is an imaginary axis that extends parallel to the Z axis. Unless otherwise specified, the direction parallel to the axial direction of the central axis J1, i.e., the Z axis direction, is simply called the "axial direction," the radial direction centered on the central axis J1 is simply called the "radial direction," and the circumferential direction centered on the central axis J1 is simply called the "circumferential direction." In this embodiment, the lower side corresponds to "one axial side," and the upper side corresponds to "the other axial side."

Note that the terms "upper", "upper side", and "lower side" are simply names used to describe the relative positional relationships of the various parts, and the actual positional relationships may be other than those indicated by these names.

The pump 10 of this embodiment shown in FIG. 1 is, for example, an electric pump mounted on a vehicle. The pump 10 pumps a fluid O inside the vehicle. The fluid O pumped by the pump 10 is, for example, oil. The oil is, for example, ATF (Automatic Transmission Fluid). As shown in FIG. 1, the pump 10 of this embodiment includes a housing 20, a motor 30, bearings 38 and 39, a pump mechanism 40, and an oil seal 70.

The motor 30 has a rotor 31 and a stator 32. The rotor 31 can rotate around a central axis J1. The rotor 31 has a shaft 33 and a rotor body 34. In other words, the motor 30 has a shaft 33 and a rotor body 34. Although not shown in the figure, the rotor body 34 has a rotor core fixed to the outer circumferential surface of the shaft 33 and a rotor magnet fixed to the rotor core.

The shaft 33 extends in the axial direction along the central axis J1. The shaft 33 is, for example, cylindrical and centered on the central axis J1. The shaft 33 is rotatable around the central axis J1 extending in the axial direction. The shaft 33 is supported by bearings 38 and 39 so as to be rotatable around the central axis J1. The bearings 38 and 39 are, for example, ball bearings. The shaft 33 has a small diameter portion 33a at its lower portion. The lower end of the small diameter portion 33a is the lower end of the shaft 33. The outer diameter of the small diameter portion 33a is smaller than the outer diameter of the portion of the shaft 33 located above the small diameter portion 33a. As shown in FIG. 2, in this embodiment, the small diameter portion 33a is a spline shaft portion having a plurality of spline teeth arranged at intervals in the circumferential direction on its outer circumferential surface.

As shown in FIG. 1, the stator 32 faces the rotor 31 in the radial direction with a gap therebetween. In this embodiment, the stator 32 is located radially outside the rotor 31. The stator 32 has a stator core 35, an insulator 36, and multiple coils 37. The stator core 35 is annular and surrounds the rotor body 34. Although not shown, the stator core 35 has a cylindrical core back centered on the central axis J1 and multiple teeth extending radially inward from the core back. The multiple coils 37 are attached to each of the multiple teeth via the insulators 36.

The pump mechanism 40 is connected to the shaft 33. More specifically, the pump mechanism 40 is attached to the small diameter portion 33a of the shaft 33. The pump mechanism 40 is housed inside the pump chamber 50, which will be described later. The pump mechanism 40 is a trochoid pump mechanism having an inner rotor 41 and an outer rotor 42.

The inner rotor 41 has a connecting hole 41b that penetrates the inner rotor 41 in the axial direction. The small diameter portion 33a of the shaft 33 is fitted into the connecting hole 41b. In this embodiment, the small diameter portion 33a is passed through the connecting hole 41b from above. The lower end of the small diameter portion 33a protrudes downward beyond the connecting hole 41b.

As shown in FIG. 2, in this embodiment, the connecting hole portion 41b is a spline hole portion having a plurality of spline grooves arranged at intervals in the circumferential direction on its inner peripheral surface. A plurality of spline teeth provided on the outer peripheral surface of the small diameter portion 33a are fitted into the spline grooves of the connecting hole portion 41b. As a result, in this embodiment, the shaft 33 and the inner rotor 41 are connected by a spline connection.

The inner rotor 41 has an external gear portion 41c on its radially outer surface. The external gear portion 41c has multiple teeth 41a that protrude radially outward. The multiple teeth 41a are arranged at equal intervals around the circumference. The outer edge shape of the external gear portion 41c is, for example, a trochoid curve when viewed in the axial direction. The inner rotor 41 rotates around the central axis J1 as the shaft 33 rotates around the central axis J1.

The outer rotor 42 is annular and surrounds the inner rotor 41. The radial outer surface of the outer rotor 42 is cylindrical, centered on an eccentric axis J2 that is radially eccentric with respect to the central axis J1. The eccentric axis J2 is a virtual axis that extends parallel to the central axis J1. The outer rotor 42 has an internal gear portion 42c on its radial inner surface. The internal gear portion 42c has a plurality of teeth 42a that protrude radially inward. The plurality of teeth 42a are arranged at equal intervals around the circumference. The inner edge shape of the internal gear portion 42c is, for example, a trochoid curve when viewed in the axial direction. The internal gear portion 42c meshes with the external gear portion 41c of the inner rotor 41 in a portion of the circumference. The outer rotor 42 rotates around the eccentric axis J2 as the inner rotor 41 rotates around the central axis J1. As the inner rotor 41 and the outer rotor 42 rotate, the fluid O that has flowed into the radial gap G between the inner rotor 41 and the outer rotor 42 is sent circumferentially within the pump chamber 50.

As shown in FIG. 1, the housing 20 accommodates the motor 30, the pump mechanism 40, and the oil seal 70 inside. In this embodiment, the housing 20 has a first housing member 21, a second housing member 22, and a third housing member 23. The first housing member 21, the second housing member 22, and the third housing member 23 are separate members. Each of the first housing member 21, the second housing member 22, and the third housing member 23 is a single member formed by, for example, mold casting such as die casting.

The first housing member 21 is a cylindrical member that opens upward. The first housing member 21 has a bottom 21a and a peripheral wall 21b. The bottom 21a extends in the radial direction. The bottom 21a covers the stator 32 from below. The bottom 21a has a first recess 21g that is recessed upward from the lower surface of the bottom 21a. As shown in FIG. 2, when viewed in the axial direction, the inner edge of the first recess 21g is circular with the eccentric axis J2 as its center. The central axis J1 passes through the inside of the first recess 21g. The inside of the first recess 21g forms the inside of the pump chamber 50, which will be described later.

As shown in FIG. 1, the peripheral wall portion 21b extends upward from the radial outer periphery of the bottom portion 21a. The radial inner surface of the peripheral wall portion 21b is, for example, cylindrical with the center on the central axis J1. The stator core 35 is fitted inside the peripheral wall portion 21b. The stator core 35 is fixed to the peripheral wall portion 21b by, for example, press fitting.

The first housing member 21 has a through hole 21c that passes through the bottom portion 21a in the axial direction. The through hole 21c is a circular hole centered on the central axis J1. The shaft 33 passes through the through hole 21c in the axial direction. The through hole 21c has a bearing retaining hole portion 21d, an oil seal retaining hole portion 21e, and a connection hole portion 21f.

The upper end of the bearing retaining hole 21d is the upper end of the through hole 21c. A bearing 38 is retained inside the bearing retaining hole 21d. The part of the bottom 21a where the bearing retaining hole 21d is provided is cylindrical and protrudes upward.

The oil seal retaining hole 21e is connected to the lower side of the bearing retaining hole 21d. The inner diameter of the oil seal retaining hole 21e is smaller than the inner diameter of the bearing retaining hole 21d. An oil seal 70 is held inside the oil seal retaining hole 21e. The oil seal 70 seals between the inner circumferential surface of the oil seal retaining hole 21e and the outer circumferential surface of the portion of the shaft 33 that is connected to the upper side of the small diameter section 33a.

The connection hole 21f is connected to the lower side of the oil seal retaining hole 21e. The lower end of the connection hole 21f is the lower end of the through hole 21c. The inner diameter of the connection hole 21f is smaller than the inner diameter of the oil seal retaining hole 21e. The connection hole 21f axially connects the inside of the oil seal retaining hole 21e and the inside of the first recess 21g. The small diameter portion 33a passes through the connection hole 21f in the axial direction.

The second housing member 22 is fixed to the lower side of the first housing member 21. The second housing member 22 expands in the radial direction. The upper surface of the second housing member 22 is in contact with the lower surface of the bottom portion 21a. An O-ring 71 is provided between the upper surface of the second housing member 22 and the lower surface of the bottom portion 21a. The O-ring 71 is annular and surrounds the central axis J1. In this embodiment, the O-ring 71 surrounds the pump chamber 50 described later and the second flow path portion 62 described later. The O-ring 71 seals between the radial outer peripheral edge portion on the upper surface of the second housing member 22 and the radial outer peripheral edge portion on the lower surface of the bottom portion 21a. In this embodiment, the O-ring 71 is fitted into a groove provided on the lower surface of the bottom portion 21a. The second housing member 22 has a second recess 22a recessed downward from the upper surface of the second housing member 22. The lower end of the small diameter portion 33a is inserted into the second recess 22a.

The third housing member 23 is fixed to the upper side of the first housing member 21. The radial outer peripheral edge portion on the lower surface of the third housing member 23 is in contact with the upper end surface of the peripheral wall portion 21b. The third housing member 23 closes the upper opening of the peripheral wall portion 21b. The third housing member 23 covers the motor 30 from above. The third housing member 23 has a bearing holding portion 23a that holds the bearing 39. The bearing holding portion 23a is provided on the lower surface of the third housing member 23. The bearing holding portion 23a is cylindrical, centered on the central axis J1 and open to the bottom.

The housing 20 has a pump chamber 50 that houses the pump mechanism 40 therein. In this embodiment, the pump chamber 50 is formed by blocking the lower opening of a first recess 21g provided in the first housing member 21 with the second housing member 22. In other words, the upper surface of the inner surface of the pump chamber 50 is the bottom surface of the first recess 21g. The bottom surface of the first recess 21g is the upper surface of the inner surface of the first recess 21g, and is the surface facing downward. The lower surface of the inner surface of the pump chamber 50 is the upper surface of the second housing member 22.

As shown in FIG. 2, in this embodiment, the pump chamber 50 has a circular shape centered on the eccentric axis J2 when viewed in the axial direction. The outer rotor 42 is fitted in the pump chamber 50. As shown in FIG. 1, the inner diameter of the pump chamber 50 is larger than the inner diameter of the through hole 21c. The inner peripheral surface of the inner surface of the pump chamber 50 that is located radially outward is located radially outward from the inner peripheral surface of the through hole 21c.

The first opposing recess 51 and the third opposing recess 53 are provided on the lower surface of the inner surface of the pump chamber 50. The second opposing recess 52 and the fourth opposing recess 54 are provided on the upper surface of the inner surface of the pump chamber 50. The first opposing recess 51, the second opposing recess 52, the third opposing recess 53, and the fourth opposing recess 54 are recesses that face the pump mechanism 40 in the axial direction. The first opposing recess 51 and the third opposing recess 53 are recessed downward from the lower surface of the inner surface of the pump chamber 50. The second opposing recess 52 and the fourth opposing recess 54 are recessed upward from the upper surface of the inner surface of the pump chamber 50.

The first and second opposing recesses 51 and 52 are arranged to sandwich the pump mechanism 40 in the axial direction. The first and second opposing recesses 51 and 52 are provided in a portion of the pump chamber 50 where the fluid O is sucked into the pump chamber 50. The third and fourth opposing recesses 53 and 54 are arranged to sandwich the pump mechanism 40 in the axial direction. The third and fourth opposing recesses 53 and 54 are provided in a portion of the pump chamber 50 where the fluid O is discharged to the outside of the pump chamber 50. The pair of the first and second opposing recesses 51 and 52 and the pair of the third and fourth opposing recesses 53 and 54 are arranged to sandwich the central axis J1 in the radial direction, for example.

The housing 20 has an intake passage 60 that is connected to the pump chamber 50. Fluid O flows through the intake passage 60. The fluid O flowing through the intake passage 60 is sucked into the pump chamber 50. The intake passage 60 has a first passage section 61 and a second passage section 62 that is connected to the lower end of the first passage section 61.

The first flow passage portion 61 extends in the axial direction. In this embodiment, the first flow passage portion 61 is provided in the first housing member 21. More specifically, the first flow passage portion 61 is provided in the peripheral wall portion 21b. The lower end of the first flow passage portion 61 is provided in the bottom portion 21a. The first flow passage portion 61 is located radially outside the motor 30. The upper end of the first flow passage portion 61 is located, for example, at the same position in the axial direction as the upper end of the stator core 35. The portion of the housing 20 where the first flow passage portion 61 is provided protrudes radially outward beyond other portions of the housing 20, for example.

The first flow path section 61 has a first expansion section 61a and a second expansion section 61b connected to the lower side of the first expansion section 61a. The flow path cross-sectional area of the first expansion section 61a and the flow path cross-sectional area of the second expansion section 61b increase toward the second flow path section 62. In other words, in this embodiment, the flow path cross-sectional area of the first expansion section 61a and the flow path cross-sectional area of the second expansion section 61b increase toward the lower side. The flow path cross-sectional area of each expansion section is the area of each expansion section in a cross section perpendicular to the axial direction.

The first enlarged portion 61a is located radially outward of the stator core 35. The upper end of the first enlarged portion 61a is the upper end of the first flow passage portion 61. Although not shown in the figure, the flow passage cross-sectional shape of the first enlarged portion 61a is, for example, circular. In this embodiment, the inner circumferential surface of the first enlarged portion 61a is a tapered surface whose inner diameter increases toward the bottom.

The second expansion section 61b is connected to the end of the first expansion section 61a that is closer to the second flow path section 62, i.e., the lower end. The lower end of the second expansion section 61b is the lower end of the first flow path section 61. The axial dimension of the second expansion section 61b is smaller than the axial dimension of the first expansion section 61a. The radially inner portion of the inner circumferential surface of the second expansion section 61b has a shape that curves radially inward as it moves from the top to the bottom as a whole. In this embodiment, the radially inner portion of the inner circumferential surface of the second expansion section 61b has an uneven shape.

In this embodiment, the radially outer portion of the inner circumferential surface of the second enlarged portion 61b is smoothly and continuously connected to the underside of the radially outer portion of the inner circumferential surface of the first enlarged portion 61a. The radially outer portion of the inner circumferential surface of the second enlarged portion 61b is disposed on an extension of the radially outer portion of the inner circumferential surface of the first enlarged portion 61a. The radially outer portion of the inner circumferential surface of the second enlarged portion 61b is positioned radially outward as it moves downward.

In this embodiment, the degree to which the flow path cross-sectional area of the second expansion section 61b increases as it approaches the second flow path section 62 is greater than the degree to which the flow path cross-sectional area of the first expansion section 61a increases as it approaches the second flow path section 62.

In this specification, "the degree to which the flow path cross-sectional area of a certain expansion section increases as it approaches the second flow path section" refers to, for example, the flow path cross-sectional area at the end of a certain expansion section that is closer to the second flow path section minus the flow path cross-sectional area at the end of a certain expansion section that is farther from the second flow path section, divided by the axial dimension of the certain expansion section. In other words, in this embodiment, the value obtained by subtracting the flow path cross-sectional area at the upper end of the second expansion section 61b from the flow path cross-sectional area at the lower end of the second expansion section 61b, divided by the axial dimension of the second expansion section 61b, is greater than the value obtained by subtracting the flow path cross-sectional area at the lower end of the first expansion section 61a from the flow path cross-sectional area at the upper end of the first expansion section 61a, divided by the axial dimension of the first expansion section 61a.

The second flow path section 62 is bent and extends from the first flow path section 61 to connect to the pump chamber 50. In this embodiment, the second flow path section 62 is bent at a right angle to the first flow path section 61. In this specification, "the second flow path section is bent at a right angle to the first flow path section" includes not only the case where the second flow path section is bent strictly at a right angle to the first flow path section, but also the case where the second flow path section is bent at a substantially right angle to the first flow path section. "The second flow path section is bent at a substantially right angle to the first flow path section" includes, for example, the case where the angle at which the second flow path section is bent with respect to the first flow path section is within a range of ±5° with respect to 90°.

The second flow passage section 62 extends radially inward from the lower end of the first flow passage section 61, that is, the lower end of the second enlarged section 61b. The radially inner end of the second flow passage section 62 is connected to the pump chamber 50. The radially inner end of the second flow passage section 62 is connected to the inside of the first opposing recess 51 and the inside of the second opposing recess 52. The radially inner end of the surface located on the lower side of the inner surface of the second flow passage section 62 is recessed downward. As a result, the axial dimension of the second flow passage section 62 is larger at the radially inner end. The radially inner end of the surface located on the lower side of the inner surface of the second flow passage section 62 is connected to the bottom surface of the first opposing recess 51. The bottom surface of the first opposing recess 51 is the surface located on the lower side of the inner surface of the first opposing recess 51.

In this embodiment, the second flow path section 62 is provided across the first housing member 21 and the second housing member 22. Specifically, in this embodiment, the second flow path section 62, except for the lower end, is provided on the bottom 21a of the first housing member 21. The lower end of the second flow path section 62 is provided on the second housing member 22. The surface located on the radially outer side of the inner surface of the second flow path section 62 is smoothly and continuously connected to the lower side of the part located on the radially outer side of the inner circumferential surface of the first flow path section 61. The surface located on the radially outer side of the inner surface of the second flow path section 62 is arranged on the extension line of the part located on the radially outer side of the inner circumferential surface of the first flow path section 61. The surface located on the radially outer side of the inner surface of the second flow path section 62 is located on the radially outer side as it moves downward.

As shown in FIG. 2, the width of the second flow path section 62 increases as it approaches the pump chamber 50 when viewed in the axial direction. In this embodiment, the width of the second flow path section 62 when viewed in the axial direction is the circumferential dimension of the second flow path section 62. In this embodiment, the circumferential dimension of the second flow path section 62 increases as it moves radially inward.

In this embodiment, the edges 62a and 62b on both circumferential sides of the second flow passage portion 62 extend linearly in a direction inclined relative to the radial direction when viewed in the axial direction. The inclination of the edge 62a relative to the radial direction is, for example, greater than the inclination of the edge 62b relative to the radial direction. The edges 62a and 62b are spaced apart in the circumferential direction as they move radially inward. The radially inner ends of the edges 62a and 62b are connected to the inner edge of the pump chamber 50. When viewed in the axial direction, the edge 62a extends along a tangent line TLa at the portion of the inner edge of the pump chamber 50 to which the edge 62a is connected. When viewed in the axial direction, the edge 62a is disposed on the tangent line TLa. When viewed in the axial direction, the edge 62b extends in a direction intersecting the direction of the tangent line TLb at the portion of the inner edge of the pump chamber 50 to which the edge 62b is connected.

As shown by the arrows in FIG. 1, the fluid O that flows into the intake passage 60 from the intake port (not shown) flows from the top to the bottom in the first passage section 61, and then flows into the second passage section 62. The fluid O that flows into the second passage section 62 flows radially inward in the second passage section 62 and flows into the pump chamber 50. The fluid O that flows into the pump chamber 50 enters the gap G between the inner rotor 41 and the outer rotor 42, and is sent circumferentially in the pump chamber 50 as the inner rotor 41 and the outer rotor 42 rotate. The fluid O sent circumferentially in the pump chamber 50 is discharged into the discharge passage (not shown). Although not shown, the discharge passage is a passage that connects to the pump chamber 50 and is provided in the housing 20.

According to this embodiment, the intake flow passage 60 has a first flow passage portion 61 extending in the axial direction, and a second flow passage portion 62 that extends from the first flow passage portion 61 in a bent manner and connects to the pump chamber 50. When viewed in the axial direction, the width of the second flow passage portion 62 increases as it approaches the pump chamber 50. Therefore, the flow passage cross-sectional area of the second flow passage portion 62 can be increased as it approaches the pump chamber 50. This makes it easier to flow the fluid O in the second flow passage portion 62, and increases the amount of fluid O flowing from the second flow passage portion 62 toward the pump chamber 50. Therefore, even if a pressure loss occurs in the fluid O when the fluid O flows from the first flow passage portion 61 into the second flow passage portion 62 that is bent relative to the first flow passage portion 61, a decrease in the amount of fluid O sucked from the intake flow passage 60 into the pump chamber 50 can be suppressed. Therefore, a decrease in the pump efficiency of the pump 10 can be suppressed.

In addition, according to this embodiment, the first flow path section 61 has a first enlarged section 61a in which the flow path cross-sectional area increases toward the second flow path section 62. This makes it easier to flow the fluid O into the first flow path section 61. This makes it easier to flow the fluid O from the first flow path section 61 into the second flow path section 62. This makes it easier to prevent a decrease in the amount of fluid O sucked into the pump chamber 50 from the suction flow path 60 via the second flow path section 62.

In addition, according to this embodiment, the first flow path section 61 has a second enlarged section 61b in which the flow path cross-sectional area increases toward the second flow path section 62. This makes it easier for fluid O to flow through the first flow path section 61. This makes it easier for fluid O to flow from the first flow path section 61 to the second flow path section 62. This makes it easier to prevent a decrease in the amount of fluid O sucked into the pump chamber 50 from the suction flow path 60 via the second flow path section 62.

In addition, according to this embodiment, the second expansion section 61b is connected to the end of the first expansion section 61a that is closer to the second flow path section 62. The degree to which the flow path cross-sectional area of the second expansion section 61b increases as it approaches the second flow path section 62 is greater than the degree to which the flow path cross-sectional area of the first expansion section 61a increases as it approaches the second flow path section 62. Therefore, the fluid O can be made to flow more suitably in the second expansion section 61b than in the first expansion section 61a. As a result, the fluid O can be made to flow more suitably in the first flow path section 61 as it approaches the second flow path section 62. Therefore, the fluid O can be made to flow more easily from the first flow path section 61 to the second flow path section 62. Therefore, it is possible to more effectively suppress a decrease in the amount of fluid O sucked into the pump chamber 50 from the suction flow path 60 through the second flow path section 62.

In addition, according to this embodiment, the first opposing recess 51 that faces the pump mechanism 40 in the axial direction is provided on the surface located on the lower side of the inner surface of the pump chamber 50. The second opposing recess 52 that faces the pump mechanism 40 in the axial direction is provided on the surface located on the upper side of the inner surface of the pump chamber 50. The second flow path portion 62 is connected to the inside of the first opposing recess 51 and the inside of the second opposing recess 52. Therefore, it is possible to flow the fluid O from the second flow path portion 62 to the inside of the first opposing recess 51 and the inside of the second opposing recess 52. This allows the fluid O to be supplied to the pump mechanism 40 from both sides in the axial direction through the inside of the first opposing recess 51 and the inside of the second opposing recess 52. Therefore, it is possible to easily supply the fluid O to the pump mechanism 40 in the pump chamber 50. Therefore, it is easy to increase the amount of fluid O sent by the pump mechanism 40. This makes it possible to further suppress a decrease in the pump efficiency of the pump 10.

Specifically, in this embodiment, as shown by the arrows in FIG. 1, the fluid O that flows from the second flow path portion 62 into the first opposing recess 51 flows from below into the gap G between the inner rotor 41 and the outer rotor 42. The fluid O that flows from the second flow path portion 62 into the second opposing recess 52 flows from above into the gap G between the inner rotor 41 and the outer rotor 42. This makes it easier for the fluid O to flow into the gap G between the inner rotor 41 and the outer rotor 42. Therefore, the amount of fluid O pumped by the pump mechanism 40 can be increased.

In addition, according to this embodiment, one of the edges 62a, 62b on both circumferential sides of the second flow path section 62 extends, when viewed in the axial direction, along a tangent line TLa at the portion where one of the edges 62a of the inner edge of the pump chamber 50 is connected. This makes it easier to preferably widen the portion of the second flow path section 62 that is connected to the pump chamber 50 in the circumferential direction. This makes it easier to more preferably allow the fluid O to flow from the second flow path section 62 into the pump chamber 50. This makes it possible to more effectively prevent a decrease in the amount of fluid O sucked into the pump chamber 50 from the second flow path section 62.

According to this embodiment, the housing 20 has a first housing member 21 and a second housing member 22 fixed to the lower side of the first housing member 21. The first flow path portion 61 is provided in the first housing member 21. The second flow path portion 62 is provided across the first housing member 21 and the second housing member 22. Therefore, the portion of the second flow path portion 62 that is connected to the first flow path portion 61 in the axial direction can be opened on the lower surface of the first housing member 21. As a result, when the first housing member 21 is made by die casting or other mold casting, the first flow path portion 61 and a portion of the second flow path portion 62 can be made by a portion of the mold located at the lower side of a pair of molds combined in the axial direction. In this case, after the first housing member 21 is molded, a portion of the mold that molds the first flow path portion 61 and a portion of the second flow path portion 62 is pulled out downward from within each flow path portion. Here, if the first flow passage section 61 has portions such as the first enlarged section 61a and the second enlarged section 61b, in which the flow passage cross-sectional area increases toward the lower side, as in this embodiment, it becomes easier to pull a part of the mold downward. In other words, the first enlarged section 61a and the second enlarged section 61b are provided, so that a pull taper is provided in the first flow passage section 61, and it becomes easier to pull a part of the mold that molds the first flow passage section 61 from inside the molded first flow passage section 61. Therefore, it becomes easier to produce the first housing member 21 by mold casting such as die casting.

In addition, according to this embodiment, the second flow path section 62 is bent at a right angle to the first flow path section 61. In such a case, pressure loss is more likely to occur in the fluid O flowing from the first flow path section 61 to the second flow path section 62. In contrast, according to this embodiment, as described above, even if pressure loss occurs in the fluid O, it is possible to suppress a decrease in the amount of fluid O sucked into the pump chamber 50 from the suction flow path 60. In this way, the effect of suppressing a decrease in the amount of fluid O sucked into the pump chamber 50 from the suction flow path 60 is more effectively obtained in a configuration in which the second flow path section 62 is bent at a right angle to the first flow path section 61.

The present invention is not limited to the above-described embodiment, and other configurations and methods may be adopted within the scope of the technical concept of the present invention. The first flow path section may not have a first expansion section, and may not have a second expansion section. For example, in the above-described embodiment, if the first expansion section 61a is not provided and only the second expansion section 61b is provided, then, for example, the second expansion section 61b corresponds to the first expansion section.

The second flow path section may extend in any direction as long as it bends relative to the first flow path section and connects to the pump chamber. The second flow path section may extend in a direction inclined relative to the radial direction. The angle at which the second flow path section bends relative to the first flow path section may be greater than 90° or less than 90°. The degree to which the flow path cross-sectional area of the second expansion section increases as it approaches the second flow path section may be less than the degree to which the flow path cross-sectional area of the first expansion section increases as it approaches the second flow path section.

Both of the edges on both circumferential sides of the second flow path section may extend, when viewed in the axial direction, along a tangent to the inner edge of the pump chamber where the edges are connected. That is, for example, in the above-described embodiment, like edge 62a, edge 62b may also extend, when viewed in the axial direction, along a tangent to the inner edge of the pump chamber 50 where edge 62b is connected. Both of the edges on both circumferential sides of the second flow path section may not extend, when viewed in the axial direction, along a tangent to the inner edge of the pump chamber where the edges are connected.

The suction passage may be provided in any manner in the housing. The pump chamber may be provided in any manner in the housing. The number of housing members constituting the housing is not particularly limited. The type of pump mechanism is not particularly limited. The pump mechanism may be a pump mechanism other than the trochoid pump mechanism described above.

At least one of the first and second opposing recesses may not be provided. That is, for example, in the above-mentioned embodiment, either one of the first and second opposing recesses 51 and 52 may not be provided, or both the first and second opposing recesses 51 and 52 may not be provided. At least one of the third and fourth opposing recesses may not be provided. That is, for example, in the above-mentioned embodiment, either one of the third and fourth opposing recesses 53 and 54 may not be provided, or both the third and fourth opposing recesses 53 and 54 may not be provided.

The use of the pump to which the present invention is applied is not particularly limited. The pump may be mounted on equipment other than a vehicle. The fluid pumped by the pump is not particularly limited and may be, for example, water. The configurations and methods described above in this specification may be combined as appropriate within the scope of not being mutually inconsistent.

10...pump, 20...housing, 21...first housing member, 22...second housing member, 30...motor, 33...shaft, 40...pump mechanism, 50...pump chamber, 51...first opposing recess, 52...second opposing recess, 60...suction flow path, 61...first flow path portion, 61a...first enlarged portion, 61b...second enlarged portion, 62...second flow path portion, 62a, 62b...edge portion, J1...center axis, TLa...tangent line

Claims (5)

a motor having a shaft rotatable about a central axis extending in an axial direction;
a pump mechanism coupled to the shaft;
a housing that accommodates the motor and the pump mechanism therein;
Equipped with
The housing includes:
a pump chamber that accommodates the pump mechanism therein;
a suction passage connected to the pump chamber;
having
The intake passage is
A first flow path portion extending in an axial direction;
a second flow path portion that is bent and extends from the first flow path portion and is connected to the pump chamber;
having
When viewed in the axial direction, the width of the second flow path portion increases toward the pump chamber ,
The first flow path portion has a first enlarged portion in which a flow path cross-sectional area increases toward the second flow path portion,
The first flow path portion has a second enlarged portion in which a flow path cross-sectional area increases toward the second flow path portion,
the second expansion portion is connected to an end portion of the first expansion portion that is closer to the second flow path portion,
a degree to which the flow path cross-sectional area of the second enlarged portion increases toward the second flow path portion is greater than a degree to which the flow path cross-sectional area of the first enlarged portion increases toward the second flow path portion . a first opposing recess portion that faces the pump mechanism in the axial direction is provided on one of the inner surfaces of the pump chamber;
a second opposing recess portion that faces the pump mechanism in the axial direction is provided on the inner surface of the pump chamber, the second opposing recess portion being disposed on the other axial side of the inner surface of the pump chamber;
The pump according to claim 1 , wherein the second flow passage portion is connected to an interior of the first opposed recess and an interior of the second opposed recess. The pump chamber is circular when viewed in the axial direction,
3. The pump according to claim 1, wherein at least one of the edge portions on both circumferential sides of the second flow path portion extends, when viewed in the axial direction, along a tangent at a portion of the inner edge of the pump chamber to which the one edge portion is connected. The housing includes:
A first housing member;
a second housing member fixed to one axial side of the first housing member;
having
The first flow path portion is provided in the first housing member,
The pump according to claim 1 , wherein the second flow path portion is provided across the first housing member and the second housing member. The pump according to claim 1 , wherein the second flow path portion is bent at a right angle to the first flow path portion.

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