Pump device

Abstract

To provide a pump device for achieving a lower profile and a smaller size while securing mechanical strength.SOLUTION: The pump device includes a rotor unit Ru for giving pumping operation to fluid, a housing H defining a storage chamber 13 storing a suction port 15, a discharge port 16, and the rotor unit, and a rotary shaft 30 joined to the rotor unit and protruded to the outside of the housing, and adapted to be rotated around a predetermined axis S, the housing H including a bottomed cylindrical housing body 10 integrally having a joint wall 11 to be joined to an applied object, an outer peripheral wall 12 cooperated with the joint wall to define the storage chamber, and a spigot part 14 protruded from the joint wall in the axial direction and adapted to be fitted to the applied object, and a plane housing cover 20 joined to the housing body to close the storage chamber.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a pump device that inhales, pressurizes, and discharges a fluid, and particularly 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 device.

Background Art

[0002] As a conventional pump device, there is known an oil pump including a pump body including an inner rotor and an outer rotor, a pump body defining a housing chamber for housing the pump body, a pump cover covering the pump body housing the pump body, and a pump shaft coupled to the pump body 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 bolts (see, for example, Patent Document 1).

[0003] In this oil pump, since the pump body and the pump cover are only fixed to the case using bolts, positioning cannot be performed with high precision in a direction perpendicular to the pump shaft, that is, in a direction along the joint surface. Further, the width dimensions of the pump body and the pump cover are each sufficiently larger than the width dimension of the pump body, resulting in a structure that causes the oil pump to be enlarged in the axial direction of the pump shaft. Furthermore, the pump shaft is supported by one bearing provided in the pump cover, and since the tip side of the pump shaft is supported by a bearing in the case after assembly to the case, the oil pump does not have a structure in which the pump shaft is reliably supported.

[0004] As another pump device, there is known an internal gear pump including a trochoid including an inner rotor and an outer rotor, a casing defining a trochoid housing recess for housing the trochoid, a cover for closing the trochoid housing recess, and a drive shaft coupled to the inner rotor and protruding from the cover, wherein an outer wall surface of the cover is joined to a joint surface of a fixing plate of the equipment body and fixed to the fixing plate using screws (see, for example, Patent Document 2).

[0005] In this internal gear pump, since the cover is provided with an inner fitting portion that fits into a fitting hole of the fixing plate, the casing and the cover can be positioned in a direction along the joint surface with respect to the fixing plate. However, if the plate thickness of the cover is reduced in order to make the pump thinner in the axial direction of the drive shaft, the surface rigidity of the cover around the inner fitting portion decreases, and there is a risk that the desired positioning and mechanical strength cannot be ensured.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a pump device that can solve the problems of the above prior art and achieve thinning and miniaturization while ensuring mechanical strength.

Means for Solving the Problems

[0008] The pump device of the present invention includes a rotor unit that pumps a fluid, a housing that defines a suction port, a discharge port, and a housing chamber for housing the rotor unit, and a rotating shaft that is coupled to the rotor unit, protrudes outside the housing, and rotates around a predetermined axis. The housing integrally has a bottomed cylindrical housing body having a joining wall joined to an object to be applied, an outer peripheral wall that cooperates with the joining wall to define the housing chamber, and an in-roll portion that protrudes axially outward from the joining wall and is fitted to the object to be applied, and a flat housing cover coupled to the housing body to close the housing chamber. See, the housing body includes a first bearing hole that rotatably supports one end region of the rotating shaft inside the insertion portion, and the housing cover includes a second bearing hole that rotatably supports the other end region of the rotating shaft. It is configured.

[0009] In the above pump device, a configuration may be adopted in which the wall thickness dimension of the joining wall is smaller than the wall thickness dimension of the outer peripheral wall.

[0010] In the above pump device, a configuration may be adopted in which the suction port and the discharge port are provided in the joining wall around the in-roll portion.

[0011] In the above pump device, the housing body and the housing cover include a plurality of insertion holes through which bolts for fixing to an object to be applied are inserted, and a configuration may be adopted in which the wall thickness dimension of the peripheral region of the insertion hole is formed larger than the wall thickness dimension of other regions of the outer peripheral wall.

[0012] In the above pump device, a configuration may be adopted in which the wall thickness dimension of the housing cover is larger than the wall thickness dimension of the joining wall of the housing body and smaller than the wall thickness dimension of the outer peripheral wall of the housing body.

[0014] In the above pump device, a configuration may be adopted in which the housing cover includes an annular convex portion that protrudes axially outward around the second bearing hole.

[0015] In the above pump device, a configuration may be adopted in which the housing cover includes a fitting convex portion that is fitted to the fitting concave portion of the housing body.

[0016] In the above pump device, the fitting recess of the housing body may be formed as a part of the inner edge portion that defines the accommodation chamber.

[0017] In the above pump device, the housing body may include a screw hole for screwing in a screw, the housing cover may include a circular hole for passing the screw, and the housing cover may be coupled to the housing body by the screw.

[0018] In the above pump device, the rotor unit may include an inner rotor that rotates integrally with the rotation shaft and an outer rotor that rotates in conjunction with the inner rotor.

Advantages of the Invention

[0019] According to the pump device having the above configuration, it is possible to achieve thinning and miniaturization while ensuring mechanical strength.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The pump device M according to an embodiment is joined and fixed to the cylinder block CB of an internal combustion engine as an application object. Here, as shown in FIG. 1, the cylinder block CB as an application object includes a joint surface 1 for joining the pump device M, a cylindrical fitting recess 2, an outlet 3 for working oil, an inlet 4 for working oil, and three screw holes 5 for screwing in bolts B.

[0022] As shown in FIGS. 2 to 5, the pump device M includes a housing body 10 and a housing cover 20 as a housing H, a rotating shaft 30 centered on a predetermined axis S, an inner rotor 40 and an outer rotor 50 as a rotor unit Ru, and screws b for fastening the housing cover 20 to the housing body 10.

[0023] The housing body 10 is formed in a bottomed cylindrical shape using a metal material such as steel, cast iron, sintered steel, or aluminum alloy, and as shown in FIGS. 4 and 5, includes a joint wall 11, an outer peripheral wall 12, a housing chamber 13, an inner inlet portion 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.

[0024] As shown in FIG. 6, the joint wall 11 is formed in a flat plate shape perpendicular to the axis S with a wall thickness dimension T1, and defines an outer wall surface 11a joined to the joint surface 1 of the cylinder block CB as an application object and an inner wall surface 11b with which the end surfaces 41 and 51 of the rotor unit Ru are in close contact and slide. As shown in FIGS. 6 and 7, the outer peripheral wall 12 projects cylindrically in the axial direction S from the outer edge region of the joining wall 11 to define an annular end face 12a, and has a wall thickness dimension T2 in a region away from the insertion hole 18 and a wall thickness dimension T3 in the peripheral region of the insertion hole 18. Here, the wall thickness dimension T2 is formed to be larger than the wall thickness dimension T1 of the joining wall 11. Also, the wall thickness dimension T3 of the peripheral region of the insertion hole 18 is formed to be larger than the wall thickness dimension T2 of the other regions away from the insertion hole 18.

[0025] In this way, the flat joining wall 11 and the cylindrical outer peripheral wall 12 are integrally formed. Therefore, compared with the conventional structure in which the joining wall is formed on a separate flat plate from the outer peripheral wall and joined, the bending rigidity of the region where the joining wall 11 and the outer peripheral wall 12 are continuous can be increased. As a result, even if the joining wall 11 is formed thin, the mechanical strength of the entire housing body 10 and the surface rigidity of the joining wall 11 can be ensured. In particular, since the joining wall 11 is joined to the joining surface 1 of the cylinder block CB as the object to which it is applied, its deformation can be further suppressed or prevented.

[0026] The accommodation chamber 13 is a space defined by the joining wall 11 and the outer peripheral wall 12, and rotatably accommodates the rotor unit Ru. Also, as shown in FIGS. 8 and 9, the accommodation chamber 13 includes an arcuate surface 13a that forms a part of a cylindrical surface centered on an axis S1 that is parallelly offset from the axis S. The arcuate surface 13a functions as an outer peripheral support surface that slidably supports the outer peripheral surface 53 of the outer rotor 50 that forms a part of the rotor unit Ru. Also, the inner edge portion of the arcuate surface 13a is a part of the inner edge portion that defines the accommodation chamber 13, and also functions as a fitting concave portion for fitting the fitting convex portion 22 of the housing cover 20.

[0027] The inflow portion 14 protrudes outward from the joint wall 11 in the direction of the axis S, and is formed in a cylindrical shape centered on the axis S and thicker than the wall 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 inflow portion 14 is closely fitted into the fitting recess 2 formed in the joint surface 1. As a result, the pump device M is highly accurately positioned on the joint surface 1 in the direction perpendicular to the axis S. Therefore, when a driven rotating body (for example, the gear 6) coupled to the rotating shaft 30 is rotationally driven by a driving rotating body of an internal combustion engine, the driven rotating body can be highly accurately positioned with respect to the driving rotating body. Further, although the inflow portion 14 is formed to protrude from the thin plate-like joint wall 11, 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 the rigidity of the inflow portion 14 can also be ensured. As a result, the inflow portion 14 can be reliably fitted into the fitting recess 2.

[0028] The suction port 15 is formed to penetrate from the outer wall surface 11a to the inner wall surface 11b in the joint wall 11 around the inflow portion 14 so as to form a contour that gradually expands in the rotational direction. In a state where the pump device M is joined to the cylinder block CB, the hydraulic oil guided from the outlet 3 is sucked into the accommodation chamber 13 through the suction port 15.

[0029] The discharge port 16 is formed to penetrate from the outer wall surface 11a to the inner wall surface 11b in the joint wall 11 around the inflow portion 14 and in a region on the opposite side of the suction port 15 with the inflow portion 14 interposed therebetween so as to form a contour that tapers in the rotational direction. In a state where the pump device M is joined to the cylinder block CB, the hydraulic oil pressurized in the accommodation chamber 13 is discharged toward the inlet 4 through the discharge port 16.

[0030] The bearing hole 17 is formed in a cylindrical shape centered on the axis S inside the inflow portion 14 so as to rotatably support one end side region 31 of the rotating shaft 30. Thus, since the bearing hole 17 is formed coaxially (axis S) inside the inlay portion 14 provided in the joint wall 11 with enhanced surface rigidity, sufficient mechanical strength can be ensured to support the rotating shaft 30.

[0031] The three insertion holes 18 are for inserting bolts B that are screwed into the screw holes 5 of the cylinder block CB, and are formed to penetrate in the direction of axis S from the end face 12a to the outer wall face 11a in a region away from the accommodation chamber 13 of the outer peripheral wall 12. Here, since the wall thickness dimension T3 of the peripheral region of the three insertion holes 18 is formed larger than the wall thickness dimension T2 of other regions, sufficient mechanical strength can be ensured to withstand the tightening load (stress) of the bolt B.

[0032] One screw hole 19 is for screwing a screw b that couples the housing cover 20 to the housing body 10, and is formed in the end face 12a in a thick-walled region near one insertion hole 18.

[0033] The housing cover 20 is coupled to the housing body 10 to close the accommodation chamber 13 of the housing body 10, and is formed in a flat plate shape with a wall thickness dimension T4 using materials such as steel, cast iron, sintered steel, and aluminum alloy. And, as shown in FIGS. 4 and 5, the housing cover 20 includes a coupling wall 21, a fitting convex portion 22, a bearing hole 23 as a second bearing hole, an annular convex portion 24, three insertion holes 25, and one circular hole 26. Here, as shown in FIG. 6, the wall thickness dimension T4 of the region of the coupling wall 21 of the housing cover 20 is set to be larger than the wall thickness dimension T1 of the joint wall 11 of the housing body 10 and smaller than the wall thickness dimension T2 of the outer peripheral wall 12 of the housing body 10. Thereby, while reducing the width dimension W in the axis S direction of the pump device M, sufficient mechanical strength of the entire housing H can be ensured.

[0034] The coupling wall 21 is formed as a flat surface perpendicular to the axis S and is coupled in close contact with the end face 12a of the housing body 10. The fitting convex portion 22 is formed in a disk shape that protrudes in the direction of the axis S from the coupling wall 21 around the axis S1 near the center of the housing cover 20, and defines an outer peripheral surface 22a and an inner wall surface 22b. The outer peripheral surface 22a is fitted to the inner edge portion of the arc surface 13a as the fitting recess of the housing body 10. The inner wall surface 22b forms a flat surface perpendicular to the axis S so that the end faces 42, 52 of the rotor unit Ru are in close contact and slide.

[0035] Here, by fitting the fitting convex portion 22 so as to be slightly press-fitted into the fitting recess (arc surface 13a), the housing cover 20 can be coupled so as not to fall off from the housing body 10 when handling the pump device M only by a simple fitting operation, and the mechanical strength and rigidity of the entire housing H can be increased.

[0036] The bearing hole 23 is formed in a cylindrical shape centered on the axis S so as to rotatably support the other end side region 32 of the rotating shaft 30. The annular convex portion 24 is formed in a cylindrical shape that protrudes outward in the direction of the axis S around the bearing hole 23. And the annular convex portion 24 serves to increase the mechanical strength around the bearing hole 23.

[0037] The three insertion holes 25 are for inserting bolts B to be screwed into the screw holes 5 of the cylinder block CB, and are formed as circular holes penetrating in the direction of the axis S at positions corresponding to the three insertion holes 18 of the housing body 10. One circular hole 26 is for passing a screw b for coupling the housing cover 20 to the housing body 10, and is formed near one insertion hole 25.

[0038] As described above, since the housing H is composed of the bottomed cylindrical housing body 10 integrally provided with the joining wall 11 and the outer peripheral wall 12 and the flat housing cover 20, the bending rigidity and mechanical strength can be increased as compared with the case where the joining wall is formed separately from the outer peripheral wall as a simple flat plate as in the prior art. Therefore, the wall thickness dimension T1 of the joining wall 11 can be formed to be thin, and thus, as shown in FIG. 6, the width dimension W in the axial direction S of the pump device M can be reduced, and thinning and miniaturization can be achieved. Further, since the mechanical strength and surface rigidity can be ensured even if the wall thickness of the joining wall 11 is reduced, the rigidity of the inlay portion 14 integrally formed with the joining wall 11 can also be ensured. Furthermore, since the fitting convex portion 22 of the housing cover 20 is fitted and joined to the fitting concave portion (the inner edge portion of the arc surface 13a) of the housing body 10 of the housing H, the mechanical strength and rigidity of the entire housing H are increased, and the bearing holes 17 and 23 can be positioned coaxially (axis S) with high precision.

[0039] The rotating shaft 30 is formed in a columnar shape extending in the axial direction S using a steel material or the like, and one end side region 31 is fitted into the bearing hole 17 of the housing body 10, and the other end side region 32 is fitted into the bearing hole 23 of the housing cover 20 and is supported so as to be rotatable about the axis S. In this way, since one end side region 31 and the other end side region 32 of the rotating shaft 30 are supported with respect to the housing H, as compared with the structure in which only one end side region is supported by the housing and the other end side region is supported by the object to be applied as in the prior art, the rotating shaft 30 can be supported with high precision so as to be rotatable about the axis S without causing an inclination of the axis S.

[0040] Here, as shown in FIGS. 1 to 3, the rotating shaft 30 is shown in a simple form slightly protruding from the housing H in the axial direction S, and the details of the end portions are omitted. In practice, when the driving force of the driving rotating body of the internal combustion engine is transmitted in the other end region 32 where the rotating shaft 30 protrudes from the housing cover 20, for example, a driven rotating body such as a gear, a sprocket, or a pulley is connected. When the driving force of the driving rotating body of the electric motor (for example, a rotor or a drive shaft) is transmitted, it is formed to be connected to the driving rotating body via a transmission member or directly. On the other hand, when the driving force of the driving rotating body of the internal combustion engine is transmitted in the one end region 31 where the rotating shaft 30 protrudes from the joint wall 11 of the housing body 10, for example, it is formed to be directly connected to the driving rotating body.

[0041] The rotor unit Ru is arranged in the accommodation chamber 13 to exert a pumping action of sucking, pressurizing, and discharging the hydraulic oil, and is composed of an inner rotor 40 and an outer rotor 50. The inner rotor 40 is formed as an external gear having a tooth profile with a trochoid curve using a metal material such as steel or sintered steel. As shown in FIGS. 4 and 5, the inner rotor 40 includes an end face 41 that slides on the inner wall surface 11b of the housing body 10, an end face 42 that slides on the inner wall surface 22b of the housing cover 20, a fitting hole 43 for fitting the rotating shaft 30, four convex portions 44, and four concave portions 45. Then, the inner rotor 40 rotates integrally with the rotating shaft 30 in the direction of arrow R around the axis S.

[0042] The outer rotor 50 is formed as an internal gear having a tooth profile that can mesh with the inner rotor 40 using a metal material such as steel or sintered steel. As shown in FIGS. 4 and 5, the outer rotor 50 includes an end face 51 that slides on the inner wall surface 11b of the housing body 10, an end face 52 that slides on the inner wall surface 22b of the housing cover 20, a cylindrical outer peripheral surface 53 centered on the axis S1, five convex portions 54, and five concave portions 55. The outer peripheral surface 53 is in slidable contact with the arc surface 13a of the housing body 10. The five convex portions 54 and the five concave portions 55 are formed so as to partially mesh with the four convex portions 44 and the four concave portions 45 of the inner rotor 40.

[0043] And, the outer rotor 50 rotates in the same direction as the inner rotor 40 about the axis S1 at a speed slower than that of the inner rotor 40 while being interlocked with the rotation of the inner rotor 40 that rotates about the axis S. Also, due to the partial meshing of the inner rotor 40 and the outer rotor 50, a pumping action of suction, pressurization, and discharge continuously occurs between the two.

[0044] The assembly operation of the pump device M having the above configuration will be described. In advance, the housing body 10, the housing cover 20, the rotating shaft 30, the rotor unit Ru (inner rotor 40 and outer rotor 50), and one screw b are prepared. First, the rotating shaft 30 is press-fitted into the fitting hole 43 of the inner rotor 40 and fixed so as to rotate integrally with the inner rotor 40. Note that not only simple press-fitting but also means such as a key groove and a key may be employed to reliably regulate relative rotation.

[0045] Subsequently, the inner rotor 40 and the outer rotor 50 are fitted into the accommodation chamber 13 of the housing body 10, and one end side region 31 of the rotating shaft 30 is rotatably inserted into the bearing hole 17 of the housing body 10. Subsequently, the housing cover 20 is coupled to the housing body 10 so as to approach the housing body 10 from the direction of the axis S and close the accommodation chamber 13. Specifically, the other end side region 32 of the rotating shaft 30 is rotatably inserted into the bearing hole 23 of the housing cover 20, and the fitting convex portion 22 of the housing cover 20 is fitted into the fitting concave portion (inner edge portion of the arc surface 13a) of the housing body 10.

[0046] Then, 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. As a result, with the rotor unit Ru to which the rotary shaft 30 is coupled being housed, the housing cover 20 is coupled to the housing body 10, completing the assembly of the pump device M. Note that the above assembly procedure is an example, and assembly may be performed using other procedures.

[0047] In the above configuration, the housing cover 20 is coupled to the housing body 10 by fitting the fitting convex portion 22 into the fitting concave portion (the inner edge portion of the arc surface 13a, which is a part of the inner edge portion defining the housing chamber 13). Thus, the mechanical strength of the housing H can be increased, and the housing cover 20 can be prevented from falling off. In particular, in the above embodiment, since the housing cover 20 is fastened to the housing body 10 using the screw b, the housing cover 20 can be reliably prevented from falling off when the pump device M is handled during transportation or the like.

[0048] Next, the operation of mounting the pump device M according to an embodiment on a cylinder block CB as an application object will be described. Here, as shown in FIG. 1, as an example, the gear 6 is applied as the driven rotating body coupled to the rotary shaft 30. First, the pump device M as a product, the gear 6, three bolts B, and a packing (not shown) as a liquid or a molded body are prepared. Subsequently, the gear 6 is coupled to the other end side region 32 of the rotary shaft 30 of the pump device M.

[0049] Subsequently, the pump device M is brought closer to the cylinder block CB in the direction of the axis S, and with a packing (not shown) interposed between the joining wall 11 (outer wall surface 11a) and the joining surface 1, the inlet portion 14 is fitted into the fitting recess 2. As a result, the pump device M is positioned with high precision on the joining surface 1 in the direction perpendicular to the axis S. Therefore, the gear 6 coupled to the rotary shaft 30 is positioned with high precision with respect to the drive rotating body (not shown) of the internal combustion engine. Subsequently, the three bolts B are inserted into the corresponding insertion holes 25, 18 respectively, screwed into the three screw holes 5, and the pump device M is fixed to the cylinder block CB. Thereby, the mounting operation of the pump device M to the cylinder block CB is completed.

[0050] In the above mounting operation, since the housing H of the pump device M achieves thinning while ensuring mechanical strength and rigidity, when the inlay portion 14 is fitted into the fitting recess 2, the fitting operation can be easily performed without causing deformation or the like in the joint wall 11 around the inlay portion 14.

[0051] Next, the operation of the pump device M will be briefly described. In addition, in the state where the pump device M is 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.

[0052] In this state, when the rotating shaft 30 rotates in the direction of arrow R via the gear 6, the inner rotor 40 rotates in the direction of arrow R, and the outer rotor 50 rotates in the same direction in conjunction with the inner rotor 40. Then, the space Cin sandwiched 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 Cin through the suction port 15.

[0053] And when the space Cin reaches the maximum, the suction action ends. Subsequently, the space Cout gradually shrinks, causing a pressurizing action on the sucked hydraulic oil, and the pressurized hydraulic oil is discharged toward the inlet 4 through the discharge port 16. By continuously repeating the above series of operations, the hydraulic oil is continuously sucked, pressurized, and discharged.

[0054] As described above, according to the pump device M according to one embodiment, the housing H includes a bottomed cylindrical housing body 10 integrally having a joining wall 11 joined to the object to be applied, an outer peripheral wall 12 that cooperates with the joining wall 11 to define an accommodation chamber 13, and an inlay portion 14 that protrudes outward in the axial direction of the axis S from the joining wall 11 and is fitted to the object to be applied, and a flat housing cover 20 coupled to the housing body 10 to close the accommodation chamber 13. Therefore, while ensuring the mechanical strength and surface rigidity of the joining wall 11, the joining wall 11 can be formed into a thin plate shape, the width dimension W in the axial direction of the axis S of the pump device M can be reduced, and thinning and miniaturization can be achieved.

[0055] Here, in the housing body 10, by making the wall thickness dimension T1 of the joining wall 11 smaller than the wall thickness dimension of the outer peripheral wall 12, the width dimension W can be reduced while ensuring the mechanical strength of the entire housing H. Further, in the joining wall 11, by adopting a configuration in which the inlay portion 14, the suction port 15, and the discharge port 16 are provided, the suction port 15 can be communicated with the oil outlet 3 of the hydraulic oil and the discharge port 16 can be communicated with the oil inlet 4 of the hydraulic oil only by joining the pump device M to the joining surface of the object to be applied. Therefore, compared with a configuration in which the suction port or the discharge port is arranged in another area, the mounting operation can be simplified.

[0056] In the above embodiment, a configuration in which the rotating shaft 30 is directly supported by the bearing holes 17 and 23 is shown, but the present invention is not limited to this. If necessary, a configuration in which the rotating shaft 30 is supported via a bearing (including an inner ring, rolling elements, and an outer ring) may be adopted, or a configuration in which the rotating shaft 30 is supported via a cylindrical bush may be adopted. Further, if necessary, a configuration in which an annular seal member is arranged adjacent to the bearing may be adopted to reliably prevent leakage of the hydraulic oil.

[0057] In the above embodiment, the fitting convex portion and the fitting concave portion for fitting the housing cover to the housing body are shown as the disk-shaped fitting convex portion 22 and a part of the inner edge portion (arc surface 13a) that defines the accommodation chamber 13. However, the present invention is not limited to this. In a region radially outside the accommodation chamber, an annular convex portion as a fitting convex portion may be provided on the housing cover, and an annular groove portion as a fitting concave portion may be provided on the housing body, and a configuration in which the annular convex portion is fitted into the annular groove portion may be adopted.

[0058] In the above embodiment, a configuration in which the screw b for fastening the housing cover 20 to the housing body 10 is adopted is shown. However, the present invention is not limited to this. If the fitting between the fitting convex portion 22 and the fitting concave portion (the inner edge portion of the arc surface 13a as a part of the inner edge portion that defines the accommodation chamber 13) can be a press-fit to reliably prevent falling off, the screw b may be omitted.

[0059] In the above embodiment, as the rotor unit that exerts a pumping action, a rotor unit Ru including an inner rotor 40 and an outer rotor 50 having a trochoid tooth profile is shown. However, the present invention is not limited to this. For example, a rotor unit provided with an inner rotor and an outer rotor having an involute tooth profile, or an inner rotor and an outer rotor having other tooth profiles may be adopted. Further, as long as it is a rotor unit that exerts a pumping action on a fluid, a vane-type rotor or a rotor unit including other positive displacement rotors may be adopted.

[0060] In the above embodiment, the inner rotor 40 and the outer rotor 50 that constitute the rotor unit Ru are shown as having a configuration of a trochoid type with 4 lobes and 5 nodes. However, the present invention is not limited to this, and a configuration consisting of other numbers may be adopted.

[0061] In the above-described embodiment, the cylinder block CB of an internal combustion engine mounted on an automobile or the like was shown as an object to which the pump device M according to the present invention is applied. However, the present invention is not limited to this, and it may be applied to a transmission or other lubrication devices, or may be applied to a fluid device that uses a fluid other than hydraulic oil.

[0062] As described above, the pump device of the present invention can achieve thinning and miniaturization while ensuring mechanical strength. Therefore, it can be applied not only to an object such as an internal combustion engine of an automobile or a motorcycle with limited installation space, but also to other lubrication devices, and is further useful in a fluid device that handles a fluid other than hydraulic oil.

Explanation of Reference Numerals

[0063] CB Cylinder block (object of application) 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 b Screw H Housing 10 Housing body (housing) 11 Joint wall 12 Outer peripheral wall 13 Accommodation chamber 13a Arc surface (a part of the inner edge defining the accommodation chamber, fitting recess) 14 Inlet portion 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 convex portion 23 Bearing hole (second bearing hole) 24 annular convex part 25 insertion hole 26 circular hole 30 rotating shaft 31 one - end - side region 32 other - end - side region Ru rotor unit 40 inner rotor 50 outer rotor T1 Wall thickness dimension of the joining wall T2 Wall thickness dimension of the outer peripheral wall (wall thickness dimension of other regions) T3 Wall thickness dimension of the peripheral region of the insertion hole T4 Wall thickness dimension of the housing cover

Claims

1. A rotor unit that exerts a pumping action on a fluid, a housing that defines a suction port, a discharge port, and a housing chamber for housing the rotor unit, and a rotating shaft that is coupled to the rotor unit, protrudes outside the housing, and rotates about a predetermined axis. The housing includes a bottomed cylindrical housing body that integrally has a joining wall joined to an object to be applied, an outer peripheral wall that cooperates with the joining wall to define the housing chamber, and an in-roll portion that protrudes outward in the axial direction from the joining wall and is fitted to the object to be applied, and a flat housing cover coupled to the housing body to close the housing chamber. The housing body includes a first bearing hole that rotatably supports one end region of the rotating shaft inside the in-roll portion. The housing cover includes a second bearing hole that rotatably supports the other end region of the rotating shaft. A pump device characterized by the above.

2. The wall thickness dimension of the joining wall is smaller than the wall thickness dimension of the outer peripheral wall. The pump device according to claim 1, characterized by the above.

3. The suction port and the discharge port are provided in the joining wall around the in-roll portion. The pump device according to claim 1 or 2, characterized by the above.

4. The housing body and the housing cover include a plurality of insertion holes through which bolts for fixing to the object to be applied are inserted. In the outer peripheral wall, the wall thickness dimension of the peripheral region of the insertion hole is formed larger than the wall thickness dimension of other regions. The pump device according to any one of claims 1 to 3, characterized by the above.

5. The wall thickness dimension of the housing cover is larger than the wall thickness dimension of the joining wall and smaller than the wall thickness dimension of the outer peripheral wall. The pump device according to any one of claims 1 to 4, characterized by the above.

6. The housing cover includes an annular convex portion that protrudes outward in the axial direction around the second bearing hole. The pump device according to any one of claims 1 to 5, characterized by the above.

7. The housing cover includes a fitting convex portion that is fitted to a fitting concave portion of the housing body. The pump device according to any one of claims 1 to 6, characterized by the above.

8. The fitting concave portion is formed as a part of an inner edge portion that defines the housing chamber. The pump device according to claim 7, characterized by the above.

9. The housing body includes a screw hole for screwing in a screw, The housing cover includes a circular hole through which the screw passes, The housing cover is coupled to the housing body by the screw, The pump device according to any one of claims 1 to 8, characterized in that.

10. The rotor unit includes an inner rotor that rotates integrally with the rotating shaft and an outer rotor that rotates in conjunction with the inner rotor, The pump device according to any one of claims 1 to 9, characterized in that.

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