US20240084799A1

US20240084799A1 - Pump device

Info

Publication number: US20240084799A1
Application number: US18/274,207
Authority: US
Inventors: Norio Takehana; Takumi Sasaki
Original assignee: Mikuni Corp
Current assignee: Mikuni Corp
Priority date: 2021-04-13
Filing date: 2022-02-02
Publication date: 2024-03-14
Also published as: CN116745528A; JP2022162691A; DE112022002136T5; WO2022219886A1

Abstract

A pump device includes: a rotor unit that exerts a pumping action on fluid; a housing for defining a suction port, a discharge port, and a storage chamber that stores the rotor unit; and a rotary shaft that is combined with the rotor unit and protrudes outside the housing and that rotates about a predetermined axis line. The housing includes: a bottomed cylindrical housing body integrally having a joint wall that is joined to an application object, an outer peripheral wall that defines the storage chamber in cooperation with the joint wall, and a spigot joint part that protrudes from the joint wall in the axis line direction and that is fitted to the application object; and a plate-like housing cover that is combined with the housing body in order to close the storage chamber.

Description

TECHNICAL FIELD

The present invention relates to a pump device that sucks, pressurizes, and discharges a fluid. In particular, the present invention relates to a pump device that is joined and fixed to a joint surface of an application object such as a cylinder block of an internal combustion engine or a fluid machine.

RELATED ART

As a conventional pump device, there is known an oil pump which includes a pump including an inner rotor and an outer rotor, a pump body defining a storage chamber that stores the pump, a pump cover covering the pump body storing the pump, and a pump shaft coupled to the pump and protruding from the pump cover, in which an outer wall surface of the pump cover is joined to a joint surface of a case of a transaxle and fixed to the case using a bolt (see, for example, Patent Document 1).
In this oil pump, since the pump body and the pump cover are only fixed to the case using the bolt, positioning cannot be performed with high accuracy in a direction perpendicular to the pump shaft, that is, a direction along the joint surface.
In this structure, the pump body and the pump cover each have a width dimension sufficiently larger than a width dimension of the pump, causing an increase in the size of the oil pump in an axis line direction of the pump shaft. Furthermore, in this structure, the pump shaft is supported by one bearing provided on the pump cover, and a tip side of the pump shaft is supported by a bearing in the case after assembly of the pump shaft to the case. Hence, the oil pump does not have a structure in which the pump shaft is reliably supported.
As another pump device, there is known an internal gear pump which includes a trochoid including an inner rotor and an outer rotor, a casing defining a trochoid storage recess that stores the trochoid, a cover closing the trochoid storage recess, and a drive shaft coupled to the inner rotor and protruding from the cover, in which an outer wall surface of the cover is joined to a joint surface of a fixing plate of a device body and fixed to the fixing plate using a screw (see, for example, Patent Document 2).
In this internal gear pump, since the cover includes a spigot joint part fitted to a fitting hole of the fixing plate, the casing and the cover can be positioned with respect to the fixing plate in a direction along the joint surface. However, if a thickness of the cover is reduced in order to reduce a thickness in an axis line direction of the drive shaft, there is a risk that surface rigidity of the cover around the spigot joint part may be reduced, and desired positioning or mechanical strength may not be able to be ensured.

PRIOR-ART DOCUMENTS

Patent Documents

- Patent Document 1: Japanese Patent Laid-Open No. 2018-115592
- Patent Document 2: Japanese Patent Laid-Open No. 2020-159283

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a pump device in which the above problems of the related art are solved and reduction in thickness and size can be achieved while mechanical strength is ensured.

Means for Solving the Problems

A pump device according to the present invention is configured to include: a rotor unit, exerting a pumping action on a fluid; a housing, defining a suction port, a discharge port, and a storage chamber that stores the rotor unit; and a rotary shaft, coupled to the rotor unit, protruding outside the housing, and rotating about a predetermined axis line. The housing includes a housing body of a bottomed cylindrical shape and a housing cover of a flat plate shape, the housing body integrally having a joint wall that is joined to an application object, an outer peripheral wall that defines the storage chamber in cooperation with the joint wall, and a spigot joint part that protrudes outward in a direction of the axis line from the joint wall and is fitted to the application object, the housing cover being coupled to the housing body in order to close the storage chamber.
The above pump device may adopt a configuration in which a thickness dimension of the joint wall is smaller than a thickness dimension of the outer peripheral wall.
The above pump device may adopt a configuration in which the suction port and the discharge port are provided in the joint wall around the spigot joint part.
The above pump device may adopt a configuration in which the housing body and the housing cover each include a plurality of insertion holes each allowing a bolt to be inserted therethrough to be fixed to the application object, and the outer peripheral wall is formed to have a larger thickness dimension in a peripheral area of the insertion hole than in other areas.
The above pump device may adopt a configuration in which a thickness dimension of the housing cover is larger than the thickness dimension of the joint wall of the housing body and smaller than the thickness dimension of the outer peripheral wall of the housing body.
The above pump device may adopt a configuration in which the housing body includes inside the spigot joint part a first bearing hole rotatably supporting one end area of the rotary shaft, and the housing cover includes a second bearing hole rotatably supporting the other end area of the rotary shaft.
The above pump device may adopt a configuration in which the housing cover includes an annular protrusion protruding outward in the direction of the axis line around the second bearing hole.
The above pump device may adopt a configuration in which the housing cover includes a fitting protrusion fitted to a fitting recess of the housing body.
The above pump device may adopt a configuration in which the fitting recess of the housing body is formed as a portion of an inner edge defining the storage chamber.
The above pump device may adopt a configuration in which the housing body includes a screw hole into which a screw is screwed, the housing cover includes a circular hole through which the screw passes, and the housing cover is coupled to the housing body by the screw.
The above pump device may adopt a configuration in which the rotor unit includes an inner rotor rotating integrally with the rotary shaft and an outer rotor rotating in conjunction with the inner rotor.

Effects of the Invention

According to the pump device of the above configuration, reduction in thickness and size can be achieved while mechanical strength is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view illustrating a state before a pump device according to one embodiment of the present invention is attached to an application object.

FIG. 2 is an external perspective view of the pump device according to one embodiment as seen from a side opposite to a joint wall joined to the application object.

FIG. 3 is an external perspective view of the pump device according to one embodiment as seen from the side of the joint wall joined to the application object.

FIG. 4 is an exploded perspective view of the pump device illustrated in FIG. 2 .

FIG. 5 is an exploded perspective view of the pump device illustrated in FIG. 3 .

FIG. 6 is a cross-sectional view of the pump device according to one embodiment, cut along a plane passing through an axis line of a rotary shaft.

FIG. 7 is a perspective cross-sectional view of a housing body constituting a portion of the pump device according to one embodiment, cut along a plane passing through the axis line of the rotary shaft.

FIG. 8 is a cross-sectional view of the housing body constituting a portion of the pump device according to one embodiment, cut along a plane passing through the axis line of the rotary shaft.

FIG. 9 illustrates a relationship between a rotor unit (inner rotor and outer rotor), a suction port and a discharge port included in the pump device according to one embodiment, and is a front view of a state in which a housing cover has been removed.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings.
A pump device M according to one embodiment is joined and fixed to a cylinder block CB of an internal combustion engine as an application object.
Here, as illustrated in FIG. 1 , the cylinder block CB as the application object includes a joint surface 1 that joins the pump device M, a fitting recess 2 of a cylindrical shape, an outlet 3 for hydraulic oil, an inlet 4 for hydraulic oil, and three screw holes 5 into which a bolt B is screwed.
As illustrated in FIG. 2 to FIG. 5 , the pump device M includes a housing body 10 and a housing cover 20 as a housing H, a rotary shaft 30 centered on a predetermined axis line S, an inner rotor 40 and an outer rotor 50 as a rotor unit Ru, and a screw b that fastens the housing cover 20 to the housing body 10.
The housing body 10 is formed in a bottomed cylindrical shape using a metal material such as steel, cast iron, sintered steel, and aluminum alloy. As illustrated in FIG. 4 and FIG. 5 , the housing body 10 includes a joint wall 11, an outer peripheral wall 12, a storage chamber 13, a spigot joint part 14, a suction port 15, a discharge port 16, a bearing hole 17 as a first bearing hole, three insertion holes 18, and one screw hole 19.
As illustrated in FIG. 6 , the joint wall 11 is formed in a flat plate shape perpendicular to the axis line S with a thickness dimension T1. The joint wall 11 defines an outer wall surface 11 a joined to the joint surface 1 of the cylinder block CB being the application object, and an inner wall surface 11 b on which an end face 41 and an end face 51 of the rotor unit Ru closely slide.
As illustrated in FIG. 6 and FIG. 7 , the outer peripheral wall 12 protrudes cylindrically in the axis line S direction from an outer edge area of the joint wall 11 and defines an end face 12 a of an annular shape, and is formed to have a thickness dimension T2 in an area away from the insertion hole 18 and have a thickness dimension T3 in a peripheral area of the insertion hole 18.
Here, the thickness dimension T2 is larger than the thickness dimension T1 of the joint wall 11. The thickness dimension T3 of the peripheral area of the insertion hole 18 is larger than the thickness dimension T2 of other areas away from the insertion hole 18.
In this way, the joint wall 11 of a flat plate shape and the outer peripheral wall 12 of a cylindrical shape are integrally formed. Accordingly, compared to a conventional structure in which a joint wall is formed into a flat plate separate from and joined to an outer peripheral wall, an area where the joint wall 11 and the outer peripheral wall 12 are continuous can be improved in flexural rigidity. As a result, even if the joint wall 11 is formed thin, mechanical strength of the housing body 10 as a whole and surface rigidity of the joint wall 11 can be ensured.
In particular, since the joint wall 11 is joined to the joint surface 1 of the cylinder block CB as the application object, deformation of the joint wall 11 can further be suppressed or prevented.
The storage chamber 13 is a space defined by the joint wall 11 and the outer peripheral wall 12, and rotatably stores the rotor unit Ru.
As illustrated in FIG. 8 and FIG. 9 , the storage chamber 13 includes an arc surface 13 a constituting a portion of a cylindrical surface centered on an axis line S1 deviated in parallel from the axis line S.
The arc surface 13 a functions as an outer peripheral support surface that slidably supports an outer peripheral surface 53 of the outer rotor 50 constituting a portion of the rotor unit Ru.
An inner edge of the arc surface 13 a is a portion of an inner edge defining the storage chamber 13, and also functions as a fitting recess to which a fitting protrusion 22 of the housing cover 20 is fitted.
The spigot joint part 14 protrudes outward in the axis line S direction from the joint wall 11, and is formed in a cylindrical shape centered on the axis line S and with a thickness greater than the thickness dimension T1 of the joint wall 11. When the pump device M is joined and fixed to the joint surface 1 of the cylinder block CB, the spigot joint part 14 is closely fitted to the fitting recess 2 formed on the joint surface 1.
Accordingly, the pump device M is positioned with high accuracy on the joint surface 1 in the direction perpendicular to the axis line S. Accordingly, in the case where a driven rotating body (for example, gear 6) coupled to the rotary shaft 30 is rotationally driven by a driving rotating body of the internal combustion engine, the driven rotating body can be positioned with high accuracy with respect to the driving rotating body.
While the spigot joint part 14 is formed protruding from the joint wall 11 of a thin plate shape, since the joint wall 11 is integrally formed with the outer peripheral wall 12, the surface rigidity of the joint wall 11 can be ensured, and rigidity of the spigot joint part 14 can also be ensured. As a result, the spigot joint part 14 can be reliably fitted to the fitting recess 2.
In the joint wall 11 around the spigot joint part 14, the suction port 15 is formed penetrating from the outer wall surface 11 a to the inner wall surface 11 b so as to have a contour expanding in a direction of rotation. With the pump device M joined to the cylinder block CB, hydraulic oil guided from the outlet 3 is sucked into the storage chamber 13 through the suction port 15.
In an area in the joint wall 11 around the spigot joint part 14 on a side opposite to the suction port 15 across the spigot joint part 14, the discharge port 16 is formed penetrating from the outer wall surface 11 a to the inner wall surface 11 b so as to have a contour tapering in the direction of rotation. With the pump device M joined to the cylinder block CB, the hydraulic oil pressurized in the storage chamber 13 is discharged toward the inlet 4 through the discharge port 16.
The bearing hole 17 is formed in a cylindrical shape centered on the axis line S inside the spigot joint part 14 in order to rotatably support one end area 31 of the rotary shaft 30.
In this way, since the bearing hole 17 is formed on the same axis (axis line S) inside the spigot joint part 14 provided in the joint wall 11 whose surface rigidity is improved, sufficient mechanical strength can be ensured to support the rotary shaft 30.
The three insertion holes 18 each allow the bolt B that is to be screwed into the screw hole 5 of the cylinder block CB to be inserted therethrough. The three insertion holes 18 are formed in an area in the outer peripheral wall 12 away from the storage chamber 13 so as to penetrate in the axis line S direction from the end face 12 a to the outer wall surface 11 a.
Here, since the thickness dimension T3 of the peripheral area of the three insertion holes 18 is larger than the thickness dimension T2 of the other areas, a mechanical strength sufficient to withstand a fastening load (stress) of the bolt B can be ensured.
The one screw hole 19 allows the screw b that couples the housing cover 20 to the housing body 10 to be screwed thereinto. The one screw hole 19 is formed on the end face 12 a in a thick area in the vicinity of one insertion hole 18.
The housing cover 20 is coupled to the housing body 10 in order to close the storage chamber 13 of the housing body 10. The housing cover 20 is formed in a flat plate shape with a thickness dimension T4 using a material such as such as steel, cast iron, sintered steel, and aluminum alloy.
As illustrated in FIG. 4 and FIG. 5 , the housing cover 20 includes a coupling wall 21, the fitting protrusion 22, a bearing hole 23 as a second bearing hole, an annular protrusion 24, three insertion holes 25, and one circular hole 26.
Here, as illustrated in FIG. 6 , the thickness dimension T4 of the area of the coupling wall 21 of the housing cover 20 is set to be larger than the thickness dimension T1 of the joint wall 11 of the housing body 10 and smaller than the thickness dimension T2 of the outer peripheral wall 12 of the housing body 10.
Accordingly, mechanical strength of the housing H as a whole can be ensured while a width dimension W of the pump device M in the axis line S direction is reduced.
The coupling wall 21 is formed as a flat surface perpendicular to the axis line S and closely coupled to the end face 12 a of the housing body 10.
The fitting protrusion 22 is formed in a disk shape centered on the axis line S1 and protruding in the axis line S direction from the coupling wall 21 near the center of the housing cover 20, and defines an outer peripheral surface 22 a and an inner wall surface 22 b. The outer peripheral surface 22 a is fitted to the inner edge of the arc surface 13 a as the fitting recess of the housing body 10. The inner wall surface 22 b forms a flat surface perpendicular to the axis line S in order for an end face 42 and an end face 52 of the rotor unit Ru to closely slide thereon.
Here, by fitting so that the fitting protrusion 22 is slightly pressed into the fitting recess (arc surface 13 a), when the pump device M is handled only by simple fitting work, the housing cover 20 can be coupled to the housing body 10 so as not to fall off therefrom, and the mechanical strength and rigidity of the housing H as a whole can be improved.
The bearing hole 23 is formed in a cylindrical shape centered on the axis line S in order to rotatably support the other end area 32 of the rotary shaft 30.
The annular protrusion 24 is formed in a cylindrical shape protruding outward in the axis line S direction around the bearing hole 23. The annular protrusion 24 serves to improve the mechanical strength around the bearing hole 23.
The three insertion holes 25 each allow the bolt B that is to be screwed into the screw hole 5 of the cylinder block CB to be inserted therethrough. The three insertion holes 25 are formed as circular holes penetrating in the axis line S direction at positions corresponding to the three insertion holes 18 of the housing body 10.
The one circular hole 26 allows passage of the screw b that couples the housing cover 20 to the housing body 10 and is formed in the vicinity of one insertion hole 25.
As described above, the housing H is constituted by the housing body 10 of a bottomed cylindrical shape that integrally includes the joint wall 11 and the outer peripheral wall 12 and the housing cover 20 of a flat plate shape. Therefore, the flexural rigidity and mechanical strength of the housing H can be improved compared to a conventional case where a joint wall is formed as a simple flat plate separately from an outer peripheral wall.
Accordingly, a small thickness dimension T1 of the joint wall 11 can be achieved. Hence, as illustrated in FIG. 6 , the width dimension W of the pump device M in the axis line S direction can be reduced, and reduction in thickness and size can be achieved. Since the mechanical strength and surface rigidity can be ensured even if the thickness of the joint wall 11 is reduced, the rigidity of the spigot joint part 14 integrally formed with the joint wall 11 can also be ensured.
Furthermore, in the housing H, since the fitting protrusion 22 of the housing cover 20 is fitted and coupled to the fitting recess (inner edge of the arc surface 13 a) of the housing body 10, the mechanical strength and rigidity of the housing H as a whole can be improved, and the bearing hole 17 and the bearing hole 23 can be positioned with high accuracy on the same axis (axis line S).
The rotary shaft 30 is formed in a columnar shape extending in the axis line S direction using a steel material or the like. The rotary shaft 30 is rotatably supported about the axis line S, has the one end area 31 fitted to the bearing hole 17 of the housing body 10, and has the other end area 32 fitted to the bearing hole 23 of the housing cover 20.
In this way, since the one end area 31 and the other end area 32 of the rotary shaft 30 are supported by the housing H, compared to a conventional structure in which only one end area is supported by a housing and the other end area is supported by an application object, the rotary shaft 30 can be rotatably supported about the axis line S with high accuracy without the axis line S tilting.
Here, as illustrated in FIG. 1 to FIG. 3 , the rotary shaft 30 is illustrated in a simple form slightly protruding in the axis line S direction from the housing H, and details of ends are omitted.
Actually, the rotary shaft 30 is formed in the following manner. That is, in the other end area 32 where the rotary shaft 30 protrudes from the housing cover 20, in the case of transmitting a driving force of the driving rotating body of the internal combustion engine, the rotary shaft 30 is connected to, for example, a driven rotating body such as the gear 6, a sprocket, and a pulley; in the case of transmitting a driving force of a driving rotating body (for example, a rotor or a drive shaft) of an electric motor, the rotary shaft 30 is connected to the driving rotating body directly or via a transmission member.
On the other hand, in the one end area 31 where the rotary shaft 30 protrudes from the joint wall 11 of the housing body 10, in the case of transmitting the driving force of the driving rotating body of the internal combustion engine, the rotary shaft 30, for example, is formed to be directly connected to the driving rotating body.
The rotor unit Ru is arranged in the storage chamber 13 in order to exert a pumping action of sucking, pressurizing and discharging on hydraulic oil, and is constituted by the inner rotor 40 and the outer rotor 50.
The inner rotor 40 is formed as an outer gear having a tooth profile formed by a trochoid curve and using a metal material such as steel or sintered steel. As illustrated in FIG. 4 and FIG. 5 , the inner rotor 40 includes the end face 41 that slides on the inner wall surface 11 b of the housing body 10, the end face 42 that slides on the inner wall surface 22 b of the housing cover 20, a fitting hole 43 that fits the rotary shaft 30, and four protrusions 44 and four recesses 45.
As illustrated in FIG. 9 , the inner rotor 40 rotates integrally with the rotary shaft 30 in an arrow R direction about the axis line S.
The outer rotor 50 is formed as an inner gear having a tooth profile that may be engaged with the inner rotor 40 and using a metal material such as steel or sintered steel. As illustrated in FIG. 4 and FIG. 5 , the outer rotor 50 includes the end face 51 that slides on the inner wall surface 11 b of the housing body 10, the end face 52 that slides on the inner wall surface 22 b of the housing cover 20, the outer peripheral surface 53 of a cylindrical shape centered on the axis line S1, and five protrusions 54 and five recesses 55.
The outer peripheral surface 53 slidably contacts the arc surface 13 a of the housing body 10.
The five protrusions 54 and the five recesses 55 are formed to be partially engaged with the four protrusions 44 and the four recesses 45 of the inner rotor 40.
In conjunction with rotation of the inner rotor 40 that rotates about the axis line S, the outer rotor 50 rotates in the same direction as the inner rotor 40 about the axis line S1 at a speed slower than the inner rotor 40.
Due to partial engagement between the inner rotor 40 and the outer rotor 50, the pumping action of sucking, pressurizing and discharging continuously occurs between the inner rotor 40 and the outer rotor 50.
Assembly work of the pump device M of the above configuration is described.
The housing body 10, the housing cover 20, the rotary shaft 30, the rotor unit Ru (inner rotor 40 and outer rotor 50), and one screw b are prepared in advance.
First, the rotary shaft 30 is press-fitted into the fitting hole 43 of the inner rotor 40 and is fixed so as to rotate integrally with the inner rotor 40. In addition to simple press-fitting, a means of reliably restricting relative rotation may be adopted by adopting a key groove, a key or the like.
Subsequently, as the inner rotor 40 and the outer rotor 50 are fitted into the storage chamber 13 of the housing body 10, the one end area 31 of the rotary shaft 30 is rotatably inserted into the bearing hole 17 of the housing body 10.
Subsequently, the housing cover 20 is brought close to the housing body 10 from the axis line S direction, and is coupled to the housing body 10 so as to close the storage chamber 13.
Specifically, the other end area 32 of the rotary shaft 30 is rotatably inserted into the bearing hole 23 of the housing cover 20, and the fitting protrusion 22 of the housing cover 20 is fitted to the fitting recess (inner edge of the arc surface 13 a) of the housing body 10.
The screw b is screwed into the screw hole 19 of the housing body 10 through the circular hole 26 of the housing cover 20.
Accordingly, with the rotor unit Ru to which the rotary shaft 30 is coupled stored, the housing cover 20 is coupled to the housing body 10, and assembly of the pump device M is completed.
The above assembly procedure is an example, and assembly may be performed by any other procedure.
In the above configuration, since the housing cover 20 is coupled to the housing body 10 by fitting the fitting protrusion 22 to the fitting recess (inner edge of the arc surface 13 a, which is a portion of the inner edge defining the storage chamber 13), the mechanical strength of the housing H can be improved, and falling off of the housing cover 20 can be prevented. In particular, in the above embodiment, the housing cover 20 is fastened to the housing body 10 using the screw b. Therefore, falling off of the housing cover 20 can be reliably prevented when the pump device M is handled by transportation or the like.
Next, work of mounting the pump device M according to one embodiment on the cylinder block CB as the application object is described. Here, as illustrated in FIG. 1 , the gear 6 is applied as an example of the driven rotating body connected to the rotary shaft 30.
First, the pump device M as a product, the gear 6, three bolts B, and packing (not illustrated) as a liquid or a molded body are prepared.
Subsequently, the gear 6 is connected to the other end area 32 of the rotary shaft 30 of the pump device M.
Subsequently, the pump device M is brought close to the cylinder block CB in the axis line S direction. With the packing (not illustrated) interposed between the joint wall 11 (outer wall surface 11 a) and the joint surface 1, the spigot joint part 14 is fitted to the fitting recess 2.
Accordingly, the pump device M is positioned with high accuracy on the joint surface 1 in the direction perpendicular to the axis line S. Hence, the gear 6 coupled to the rotary shaft 30 is positioned with high accuracy with respect to the driving rotating body (not illustrated) of the internal combustion engine.
Subsequently, the three bolts B are inserted through their corresponding insertion holes 25 and 18, screwed into the three screw holes 5, and the pump device M is fixed to the cylinder block CB.
Accordingly, the work of mounting the pump device M on the cylinder block CB is completed.
In the above mounting work, since mechanical strength and rigidity are ensured while reduction in thickness is achieved in the housing H of the pump device M, when the spigot joint part 14 is fitted to the fitting recess 2, the fitting work can be easily performed without causing deformation in the joint wall 11 around the spigot joint part 14.
Next, an operation of the pump device M is briefly described.
With the pump device M mounted on the cylinder block CB, the outlet 3 of the cylinder block CB communicates with the suction port 15 of the pump device M, and the inlet 4 of the cylinder block CB communicates with the discharge port 16 of the pump device M.
In this state, when the rotary shaft 30 rotates in the arrow R direction via the gear 6, the inner rotor 40 rotates in the arrow R direction, and the outer rotor 50 rotates in the same direction in conjunction with the inner rotor 40.
Then, a space C_insandwiched between the inner rotor 40 and the outer rotor 50 gradually expands, and the hydraulic oil guided from the outlet 3 is sucked into the space C_invia the suction port 15.
At a point of time when the space C_inreaches the maximum, the sucking action ends. Subsequently, a space C_outgradually shrinks and the sucked hydraulic fluid is pressurized. The pressurized hydraulic fluid is discharged toward the inlet 4 via the discharge port 16.
By continuously repeating the above series of operations, the hydraulic oil is continuously sucked, pressurized, and discharged.
As described above, according to the pump device M according to one embodiment, the housing H includes the housing body 10 of a bottomed cylindrical shape and the housing cover 12 of a flat plate shape, the housing body 10 integrally having the joint wall 11 that is joined to the application object, the outer peripheral wall 12 that defines the storage chamber 13 in cooperation with the joint wall 11, and the spigot joint part 14 that protrudes outward in the axis line S direction from the joint wall 11 and is fitted to the application object, the housing cover 20 being coupled to the housing body 10 in order to close the storage chamber 13. Therefore, while the mechanical strength and surface rigidity of the joint wall 11 are ensured, the joint wall 11 is formed in the shape of a thin plate, the width dimension W of the pump device M in the axis line S direction can be reduced, and reduction in thickness and size can be achieved.
Here, in the housing body 10, by making the thickness dimension T1 of the joint wall 11 smaller than the thickness dimension T2 of the outer peripheral wall 12, the width dimension W can be reduced while the mechanical strength of the housing H as a whole is ensured.
Since the spigot joint part 14, the suction port 15 and the discharge port 16 are provided in the joint wall 11, by simply joining the pump device M to the joint surface 1 of the cylinder block CB as the application object, the suction port 15 can be communicated with the outlet 3 for hydraulic oil, and the discharge port 16 can be communicated with the inlet 4 for hydraulic oil. Accordingly, the mounting work can be simplified compared to a configuration in which a suction port or a discharge port is arranged in another area.
In the above embodiment, a configuration is illustrated in which the rotary shaft 30 is directly supported by the bearing holes 17 and 23. However, the present invention is not limited thereto. If necessary, a configuration may be adopted in which the rotary shaft 30 is supported via a bearing (one including an inner ring, a rolling element, and an outer ring), and a configuration may be adopted in which the rotary shaft 30 is supported via a bush of a cylindrical shape.
If necessary, a configuration may be adopted in which a seal member of an annular shape is arranged adjacent to the bearing in order to reliably prevent leakage of hydraulic oil.
In the above embodiment, the fitting protrusion 22 of a disk shape and a portion (arc surface 13 a) of the inner edge defining the storage chamber 13 are illustrated as the fitting protrusion and the fitting recess that fit the housing cover to the housing body. However, the present invention is not limited thereto. The following configuration may be adopted. In an area radially outside a storage chamber, an annular protrusion as a fitting protrusion is provided on a housing cover, an annular groove as a fitting recess is provided in a housing body, and the annular protrusion is fitted to the annular groove.
In the above embodiment, a configuration is illustrated in which the screw b is adopted which fastens the housing cover 20 to the housing body 10. However, the present invention is not limited thereto. If fitting between the fitting protrusion 22 and the fitting recess (inner edge of the arc surface 13 a as a portion of the inner edge defining the storage chamber 13) as press fitting is able to reliably prevent falling off, the screw b may be eliminated.
In the above embodiment, the rotor unit Ru including the inner rotor 40 of a trochoidal tooth profile and the outer rotor 50 is illustrated as a rotor unit exerting a pumping action. However, the present invention is not limited thereto.
For example, a rotor unit may be adopted which includes an inner rotor of an involute tooth profile and an outer rotor, or an inner rotor of any other tooth profile and an outer rotor. A rotor unit including a vane type rotor or any other positive displacement rotor may be adopted if the rotor unit exerts a pumping action on a fluid.
In the above embodiment, the inner rotor 40 and the outer rotor 50 that constitute the rotor unit Ru are illustrated to have a trochoidal configuration including four blades and five nodes. However, the present invention is not limited thereto, and a configuration including any other numbers of blades and nodes may be adopted.
In the above embodiment, the cylinder block CB of the internal combustion engine mounted on an automobile or the like is illustrated as the application object to which the pump device M according to the present invention is applied. However, the present invention is not limited thereto. The present invention may be applied to a transmission or any other lubricating device, or may be applied to a fluid machine using fluids other than hydraulic oil.
As described above, since the pump device of the present invention is able to achieve reduction in thickness and size while ensuring mechanical strength, not only can it be applied to an application object such as an internal combustion engine of an automobile or a motorcycle with limited installation space, but it can also be applied to any other lubricating device. Furthermore, the pump device is also useful in a fluid machine that handles fluids other than hydraulic oil.

DESCRIPTION OF REFERENCE NUMERALS

- CB: cylinder block (application object)
- 1: joint surface
- 2: fitting recess
- 3: outlet
- 4: inlet
- 5: screw hole
- B: bolt
- 6: gear (driven rotating body)
- M: pump device
- S: axis line
- b: screw
- H: housing
- 10: housing body (housing)
- 11: joint wall
- 12: outer peripheral wall
- 13: storage chamber
- 13 a: arc surface (portion of inner edge defining storage chamber; fitting recess)
- 14: spigot joint part
- 15: suction port
- 16: discharge port
- 17: bearing hole (first bearing hole)
- 18: insertion hole
- 19: screw hole
- 20: housing cover (housing)
- 21: coupling wall
- 22: fitting protrusion
- 23: bearing hole (second bearing hole)
- 24 annular protrusion
- 25: insertion hole
- 26: circular hole
- 30: rotary shaft
- 31: one end area
- 32: other end area
- Ru: rotor unit
- 40: inner rotor
- 50: outer rotor
- T1: thickness dimension of joint wall
- T2: thickness dimension of outer peripheral wall (thickness dimension of other areas)
- T3: thickness dimension of peripheral area of insertion hole
- T4: thickness dimension of housing cover

Claims

1. A pump device, comprising:

a rotor unit, exerting a pumping action on a fluid;

a housing, defining a suction port, a discharge port, and a storage chamber that stores the rotor unit; and

a rotary shaft, coupled to the rotor unit, protruding outside the housing, and rotating about a predetermined axis line, wherein

the housing comprises a housing body of a bottomed cylindrical shape and a housing cover of a flat plate shape, the housing body integrally comprising a joint wall that is joined to an application object, an outer peripheral wall that defines the storage chamber in cooperation with the joint wall, and a spigot joint part that protrudes outward in a direction of the axis line from the joint wall and is fitted to the application object, the housing cover being coupled to the housing body to close the storage chamber.

2. The pump device according to claim 1, wherein

a thickness dimension of the joint wall is smaller than a thickness dimension of the outer peripheral wall.

3. The pump device according to claim 1, wherein

the suction port and the discharge port are provided in the joint wall around the spigot joint part.

4. The pump device according to claim 1, wherein

the housing body and the housing cover each comprise a plurality of insertion holes each allowing a bolt to be inserted therethrough to be fixed to the application object; and

the outer peripheral wall is formed to have a larger thickness dimension in a peripheral area of the insertion hole than in other areas.

5. The pump device according to claim 1, wherein

a thickness dimension of the housing cover is larger than a thickness dimension of the joint wall and smaller than a thickness dimension of the outer peripheral wall.

6. The pump device according to claim 1, wherein

the housing body comprises inside the spigot joint part a first bearing hole rotatably supporting one end area of the rotary shaft; and

the housing cover comprises a second bearing hole rotatably supporting the other end area of the rotary shaft.

7. The pump device according to claim 6, wherein

the housing cover comprises an annular protrusion protruding outward in the direction of the axis line around the second bearing hole.

8. The pump device according to claim 1, wherein

the housing cover comprises a fitting protrusion fitted to a fitting recess of the housing body.

9. The pump device according to claim 8, wherein

the fitting recess is formed as a portion of an inner edge defining the storage chamber.

10. The pump device according to claim 1, wherein

the housing body comprises a screw hole into which a screw is screwed;

the housing cover comprises a circular hole through which the screw passes; and

the housing cover is coupled to the housing body by the screw.

11. The pump device according to claim 1, wherein

the rotor unit comprises an inner rotor rotating integrally with the rotary shaft and an outer rotor rotating in conjunction with the inner rotor.