Pumping device

Abstract

To improve pump efficiency while suppressing disturbance of flow, flow loss and the like, in a pump device including a return passage for returning a fluid to a suction passage from a discharge passage.SOLUTION: A pump device includes: a housing H having suction passages 12, 22 defining a suction port 12a at an upstream end, discharge passages 13, 23 defining a discharge port 23a at a downstream end, and a return passage 15 for returning a part of the fluid flowing through the discharge passages to the middle of the suction passage; a pump element Pe housed in the housing and rotating about a prescribed axis S to suck, pressurize and discharge the fluid; and an opening / closing valve 60 for opening and closing the return passage. The housing H has an orientation wall 16a for orienting the return passage so that the flow of suction fluid sucked from the suction port of the suction passage is deviated from the flow of return fluid returned from the return passage in the suction passage 12 at an upstream side with respect to an opening portion 15b1 opened in the suction passage.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a pump device provided with a return passage for returning a fluid from a discharge passage to a suction passage, and particularly to a pump device applied to an internal combustion engine of an outboard motor for sucking and pressurizing oil (lubricating oil or hydraulic oil) and discharging it.

Background Art

[0002] As a conventional pump device, there are known an oil pump including a pump housing having a suction passage, a discharge passage, and a drain passage for communicating the discharge passage and the suction passage, a pump element housed in the pump housing for pressurizing and discharging the sucked hydraulic oil, a spool valve (relief valve) for opening and closing the drain passage to reflux the surplus of the hydraulic oil in the discharge passage to the suction passage side, a suction pipe connected to the pump housing for introducing hydraulic oil from the outside into the suction passage, and a rectifying member fixed to the inner wall of the suction pipe for rectifying the flow of the hydraulic oil refluxed from the drain passage and the flow of the hydraulic oil supplied from the suction pipe (for example, Patent Document 1).

[0003] In this oil pump, since the rectifying member is only arranged in the region where the drain passage and the supply passage of the suction pipe intersect and rectifies, it is impossible to suppress or prevent the collision between the hydraulic oil refluxed from the drain passage and the hydraulic oil supplied from the supply passage of the suction pipe. Therefore, the suction resistance due to the flow disturbance cannot be sufficiently reduced. Further, since the rectifying member is formed as a dedicated part fixed to the suction pipe, it causes an increase in the number of parts and a higher cost.

[0004] Other pump devices include a hydraulic circuit comprising a housing having an suction oil passage, a discharge oil passage, and a return oil passage connecting the discharge oil passage and the suction oil passage; a pump element (vane pump) housed in the housing that pressurizes and discharges the suctioned hydraulic oil; and a flow straightening member that straightens the flow of oil returned from the return oil passage to the suction oil passage, wherein the flow straightening member is formed as a seal plug having a curved inclined surface to change the direction of the oil flow by approximately 90 degrees and a fixed part that fits into and is fixed to the housing (for example, Patent Document 2).

[0005] In this hydraulic circuit, the flow straightening member only bends the oil flowing out of the return oil passage and guides it into the intake oil passage; it cannot suppress or prevent collisions between the oil returning from the return oil passage and the oil flowing in the intake oil passage. Therefore, it cannot sufficiently reduce the intake resistance caused by flow turbulence. Furthermore, since the flow straightening member is a seal plug fitted into the housing, it is a separate part from the housing, leading to an increase in the number of parts and higher costs. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-255335 [Patent Document 2] Japanese Patent Publication No. 2018-53740 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above circumstances, and its objective is to provide a pump device that can improve pump efficiency by suppressing fluid flow turbulence and pressure loss, while simplifying the structure, reducing the number of parts, and lowering costs. [Means for solving the problem]

[0008] The pump device of the present invention comprises a housing having an intake passage defining an intake port at its upstream end, a discharge passage defining an outlet at its downstream end, and a return passage that returns a portion of the fluid flowing through the discharge passage to the middle of the intake passage; a pump element housed in the housing that rotates around a predetermined axis to draw in, pressurize, and discharge fluid; and an on / off valve for opening and closing the return passage, wherein the housing is located in the intake passage upstream of the opening where the return passage opens into the intake passage. A weir that protrudes from the bottom wall of the intake passage and defines a reservoir area that stores fluid in the region including the opening, It has a directional wall that directs the flow of intake fluid drawn into the intake passage from the intake port away from the flow of return fluid returned from the return passage. Furthermore, the weir section includes an inclined surface that slopes upward toward the downstream side in order to define the directional wall. It is structured as follows.

[0010] In the above-described pump device, a configuration may be adopted in which the opening of the return passage is formed along the bottom wall of the reservoir area.

[0011] In the above-described pump device, the return passage may be configured to open downstream of a position perpendicular to the intake passage.

[0012] In the above-described pump device, the housing may be configured to have a flow straightening wall protruding from the bottom wall of the reservoir region in a predetermined region including an opening where the return passage opens to the intake passage, in order to straighten the return fluid returned from the return passage so that it flows along the intake passage.

[0013] In the above-described pump device, the suction port may be configured to open vertically downward when used in the manner in which it is applied to the object.

[0014] In the above-described pump device, the discharge port may be configured to open vertically upward when used in the manner in which it is applied to the target object.

[0015] In the above-described pump device, the housing may be configured to include a housing body that opens vertically upward when applied to the object, and a housing cover connected to close the housing body from above.

[0016] In the above-described pump device, the housing body may be configured to include a pump housing recess that opens vertically upward to accommodate the pump elements, a groove-shaped passage that opens vertically upward to define a portion of the suction passage, discharge passage, and return passage, and a weir formed in the groove-shaped passage.

[0017] In the above-described pump device, the housing cover may be configured to include a groove-shaped passage that opens vertically downward in order to define a portion of the intake passage and the discharge passage.

[0018] In the above-described pump device, the housing may be configured to have pump chamber inlets at both end faces of the pump element in the axial direction, for drawing fluid into the pump chamber of the pump element.

[0019] In the above-described pump device, the pump chamber inlet may be configured to include a one-end pump chamber inlet formed at the downstream end of the suction passage of the housing body so as to face one end face of the pump element, and a other-end pump chamber inlet formed at the downstream end of the suction passage of the housing cover so as to face the other end face of the pump element.

[0020] In the above-described pump device, the suction passage of the housing cover may be configured to include an inclined surface that is inclined in the same direction as the inclined surface of the weir formed in the housing body.

[0021] In the above-described pump device, the housing may be configured such that the suction passage and the discharge passage are arranged in a V-shape with respect to the pump element.

[0022] In the above-described pump device, the housing may be configured to include a valve housing section for accommodating an on / off valve and a return passage in the region between the suction passage and the discharge passage.

[0023] In the above-described pump device, the pump element may adopt a configuration including an inner rotor that rotates integrally with a rotating shaft rotatably supported about an axis with respect to the housing, and an outer rotor that rotates in conjunction with the inner rotor.

[0024] In the above-described pump device, the inner rotor and the outer rotor may adopt a configuration that is a trochoid rotor having a trochoid tooth profile.

Advantages of the Invention

[0025] According to the pump device having the above-described configuration, it is possible to achieve simplification of the structure, reduction in the number of parts, and cost reduction, while suppressing fluid flow turbulence, pressure loss, etc., and improving pump efficiency.

Brief Description of the Drawings

[0026] [Figure 1] It is a schematic diagram showing a state in which the pump device of the present invention is applied to an outboard motor as an object to be applied. [Figure 2] It is an external perspective view showing the pump device according to the first embodiment of the present invention. [Figure 3] It is an exploded perspective view of the pump device according to the first embodiment viewed obliquely from above after being disassembled. [Figure 4] It is an exploded perspective view of the pump device according to the first embodiment viewed obliquely from below after being disassembled. [Figure 5] It is a perspective cross-sectional view of a part of the pump device according to the first embodiment with a part cut away. [Figure 6] In the pump device according to the first embodiment, it is a perspective view viewed obliquely from above after removing the housing cover constituting the housing. [Figure 7] In the pump device according to the first embodiment, it is a cross-sectional view in a plane perpendicular to the axis of the rotating shaft (horizontal plane in the state applied to the object to be applied) in a state where the on-off valve is closed. [Figure 8] In the pump device shown in FIG. 7, it is a cross-sectional view in a state where the on-off valve is open. [Figure 9]This is a cross-sectional view showing the suction passage area cut vertically when the pump device according to the first embodiment is applied to an object. [Figure 10] This is a perspective view of a pump device according to a second embodiment of the present invention, taken from above and at an oblique angle with the housing cover that constitutes the housing removed. [Figure 11] This is a cross-sectional view of the pump device according to the second embodiment, with the on / off valve in the open position, in a plane perpendicular to the axis of the rotating shaft (a horizontal plane when applied to an object). [Figure 12] This shows a pump device according to a third embodiment of the present invention, and is a perspective view taken from above and at an oblique angle with the housing cover that constitutes the housing removed. [Figure 13] This is a perspective view of the housing body, which constitutes the housing, in the pump device according to the third embodiment, viewed from above and at an oblique angle. [Figure 14] This is a cross-sectional view of the pump device according to the third embodiment, taken in a plane perpendicular to the axis of the rotating shaft (a horizontal plane when applied to an object), with the on-off valve in the open position. [Figure 15] In the example of a pump device, the flow state of the fluid in the suction passage is shown; the upper part is a streamline diagram in a vertical cross-section parallel to the axis of rotation, and the lower part is a streamline diagram in a horizontal cross-section perpendicular to the axis of rotation. [Figure 16] In the pump device according to the first embodiment, the flow state of the fluid in the suction passage is shown, with the upper part being a streamline diagram in a vertical cross-section parallel to the axis of rotation, and the lower part being a streamline diagram in a horizontal cross-section perpendicular to the axis of rotation. [Figure 17] In the pump device according to the second embodiment, the flow state of the fluid in the suction passage is shown, with the upper part being a streamline diagram in a vertical cross-section parallel to the axis of rotation, and the lower part being a streamline diagram in a horizontal cross-section perpendicular to the axis of rotation. [Figure 18] In the pump device according to the third embodiment, the flow state of the fluid in the suction passage is shown, with the upper part being a streamline diagram in a vertical cross-section parallel to the axis of rotation, and the lower part being a streamline diagram in a horizontal cross-section perpendicular to the axis of rotation. [Figure 19] This graph shows the pressure loss in a pump device as a comparative example to the pump devices according to the first to third embodiments of the present invention. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to the accompanying drawings. The pump device M1 according to the first embodiment is applied to an internal combustion engine E mounted on an outboard motor A, which is the object to which it is applied. As shown in Figure 1, outboard motor A includes an internal combustion engine E, an engine cover 1 that encloses the internal combustion engine E, a propeller 2, a gear train 3 to which the rotational force of the crankshaft of the internal combustion engine E is transmitted, a drive shaft 4 that rotates integrally with one of the gears of the gear train 3 to transmit rotational force to the propeller 2, a bracket 5 for mounting to the hull, and the like.

[0028] As shown in Figure 1, the internal combustion engine E comprises an engine body 6, an oil pan 7 attached to the bottom of the engine body 6 to store oil as a fluid, and a pump device M1 attached to the engine body 6 inside the oil pan 7. Here, in the operating conditions applied to the outboard motor A, the pump device M1 draws oil from the oil pan 7 vertically in the direction Vd via the oil strainer 8, discharges pressurized oil upward in the vertical direction Vd through the intake and discharge passages extending horizontally in the direction Hd, and draws up the oil that has flowed through the engine body 6 and returned to the oil pan 7, as shown by the dashed line, to circulate it again.

[0029] As shown in Figures 2 to 4, the pump device M1 includes a housing body 10 and a housing cover 20 as the housing H, a rotating shaft 30 centered on axis S, an inner rotor 40 and an outer rotor 50 as the pump elements Pe, an on / off valve 60, and screws b for fastening the housing cover 20 to the housing body 10.

[0030] The housing body 10 is made of a metal material such as steel, cast iron, sintered steel, or aluminum alloy and is formed in a bottomed concave shape that opens on one side in the axial direction S, that is, in the usage state applied to the outboard motor A, it opens upward in the vertical direction Vd. As shown in Figures 3 and 4, the housing body 10 includes a pump housing recess 11, an intake passage 12, a discharge passage 13, a valve housing 14, a return passage 15, a weir 16 that forms a directional wall 16a, a joint surface 17, a bearing hole 18, three screw holes 19a, and five through holes 19b.

[0031] The pump housing recess 11 is a region that houses the pump elements Pe (inner rotor 40 and outer rotor 50), and includes a thrust surface 11a that receives one end face 41, 51 of the inner rotor 40 and outer rotor 50, and an inner circumferential surface 11b that rotatably supports the outer circumferential surface 53 of the outer rotor 50 around an axis S1 parallel to the axis S.

[0032] The intake passage 12 is formed as a groove-shaped passage with a substantially rectangular cross-section that opens upward in the vertical direction Vd when applied to the outboard motor A, and extends horizontally Hd from the intake port 12a that opens downward in the vertical direction Vd defined at its upstream end to the pump chamber intake port 12b on one end facing the pump housing recess 11.

[0033] The discharge passage 13 is formed as a groove-shaped passage with a substantially rectangular cross-section that opens upward in the vertical direction Vd when applied to the outboard motor A, and is formed to extend horizontally Hd from its downstream end (the position opposite to the discharge port 23a formed in the housing cover 20 that opens upward in the vertical direction Vd) to the one-end pump chamber discharge port 13b facing the pump housing recess 11.

[0034] As shown in Figures 3 and 7, the valve housing 14 is formed as a circular cross-section drill hole extending horizontally in the direction Hd in the region sandwiched between the intake passage 12 and the discharge passage 13, and is equipped with an annular stopper 14a for contacting the valve body 61 of the on / off valve 60, and a pin hole 14b for fitting the stopper pin 64. Furthermore, the valve housing 14 slidably guides the valve body 61 of the on-off valve 60 and also functions as part of the return passage 15.

[0035] As shown in Figures 3 and 7, the return passage 15 is formed by an upstream passage 15a and a downstream passage 15b, which are groove-shaped passages with a substantially rectangular cross-section that open upward in the vertical direction Vd when applied to the outboard motor A, and an intermediate passage 15c defined by a part of the valve housing 14 between the upstream passage 15a and the downstream passage 15b. The upstream passage 15a opens in the middle of the discharge passage 13, and the downstream passage 15b opens in the middle of the intake passage 12. When the intermediate passage 15c is opened by the on / off valve 60, the upstream passage 15a and the downstream passage 15b are connected, and a portion of the oil flowing through the discharge passage 13 is returned to the intake passage 12. Here, the downstream passage 15b of the return passage 15 is oriented perpendicular to the intake passage 12, as shown in Figures 5 to 9, and has an opening 15b1 that opens into the intake passage 12. The opening 15b1 is defined as a region where a passage with an area equivalent to the area of ​​the communication hole communicating with the intermediate passage 15c (the cross-sectional area of ​​the oil flow out from the hole opened and closed by the valve body 61) intersects the intake passage 12, and is formed along the bottom wall 12c of the intake passage 12 located downstream of the weir 16, that is, the bottom wall 12c of the reservoir region Sa.

[0036] As shown in Figures 6 and 9, the weir section 16 is formed in the intake passage 12 upstream of the opening 15b1 where the return passage 15 (downstream passage 15b) opens to the intake passage 12, protruding by a predetermined height from the bottom wall 12c of the intake passage 12. The weir section 16 then defines a reservoir area Sa for accumulating oil in the region including the opening 15b1 downstream from it. In this way, by forming a reservoir region Sa, it is possible to prevent all the oil from draining out of the pump element Pe when the internal combustion engine E is stopped. Therefore, when the internal combustion engine E is started again, the pump element Pe can be operated smoothly.

[0037] Furthermore, as shown in Figure 9, the weir section 16 defines a directional wall 16a, which is formed as an inclined surface with an upward slope Us toward the downstream side of the intake passage 12 on its upper contour. The directional wall 16a plays the role of directing the intake oil diagonally upward in the intake passage 12 upstream of the opening 15b1 where the return passage 15 opens into the intake passage 12, so as to divert the flow of intake oil, which is the intake fluid drawn into the intake passage 12 from the intake port 12a, from the flow of return oil, which is the return fluid returned from the return passage 15. Here, "diverting" is synonymous with "shifting away" or "biasing," and means directing the flow of intake oil so as not to face the flow of return oil in order to avoid a direct collision between the intake oil and the return oil. Specifically, as shown in Figure 9, the streamlines F1 of the intake oil are directed in a direction away from the streamlines F2 of the return oil flowing out from the opening 15b1 of the return passage 15 (the area of ​​the communication hole that communicates with the intermediate passage 15c), along the gradient Us of the inclined surface of the directional wall 16a, that is, diagonally upward toward the downstream side, so that the streamlines F1 of the intake oil do not face the streamlines F2 of the return oil flowing out from the opening 15b1 of the return passage 15 (the area of ​​the communication hole that communicates with the intermediate passage 15c).

[0038] As shown in Figures 3 and 6, the joining surface 17 is a flat surface in a direction perpendicular to the axis S so that the joining surface 27 of the housing cover 20 is joined from the direction of the axis S. In addition, the joining surface 17 is provided with two positioning pins P for aligning the housing cover 20 in the area around the pump housing recess 11.

[0039] As shown in Figures 3 and 9, the bearing hole 18 is formed in a cylindrical shape with an axis S in the region of the pump housing recess 11 in order to rotatably support one end 31 of the rotating shaft 30. The three screw holes 19a are for screwing in screws b that connect the housing cover 20 to the housing body 10, around the pump housing recess 11 and in the area of ​​the joint surface 17. The five through holes 19b are for inserting bolts (not shown) that connect the housing H (housing body 10 and housing cover 20) to the engine body 6 in the area of ​​the joint surface 17.

[0040] In other words, the housing body 10 is formed to include a pump housing recess 11 that opens on one side in the axial direction S (upward in the vertical direction Vd) to accommodate the pump element Pe, a groove-shaped passage that opens on one side in the axial direction S (upward in the vertical direction Vd) to define a part of the suction passage 12, the discharge passage 13, and the return passage 15 (upstream passage 15a and downstream passage 15b), and a weir portion 16 that protrudes from the bottom wall 12c of the suction passage 12 which forms the groove-shaped passage. Thus, since the housing body 10 opens on one side in the axial direction S (upward in the vertical direction Vd), when the housing body 10 is molded using a mold or the like, the pump housing recess 11, suction passage 12, discharge passage 13, and return passage 15 (upstream passage 15a and downstream passage 15b) can be easily formed by molding. In particular, the weir 16 and directional wall 16a can be easily formed integrally within the groove-shaped suction passage 12.

[0041] The housing cover 20 is connected to the housing body 10 to close the housing body 10, and is made of a material such as steel, cast iron, sintered steel, or aluminum alloy, and is formed in a bottomed concave shape that opens to the other side in the axial direction S, that is, in the usage state applied to the outboard motor A, it opens downward in the vertical direction Vd. As shown in Figures 3 and 4, the housing cover 20 includes an intake passage 22, a discharge passage 23, a joint surface 27, a bearing hole 28, three circular holes 29a, and five through holes 29b.

[0042] The intake passage 22 is formed as a groove-shaped passage with a substantially rectangular cross-section that opens downward in the vertical direction Vd when applied to the outboard motor A, and is formed to extend horizontally Hd from its upstream end (the position opposite the intake port 12a formed in the housing body 10 that opens downward in the vertical direction Vd) to the other end pump chamber intake port 22b facing the pump housing recess 11 of the housing body 10. Furthermore, as shown in Figures 5 and 9, the intake passage 22 includes an inclined surface 22a that is inclined in the same direction as the inclined surface that forms an upward slope Us as the directional wall 16a of the weir 16 formed in the intake passage 12 of the housing body 10, and is formed such that the passage area on the downstream side of the inclined surface 22a is larger. In this way, by forming an inclined surface 22a that slopes in the same direction as the directional wall 16a, the passage area of ​​the suction passages 12 and 22 is not narrowed even when the weir 16 and the directional wall 16a are provided, and the oil sucked in from the suction port 12a can be guided along the inner wall surface of the suction passage 22 to the pump chamber suction port 22b at the other end.

[0043] The discharge passage 23 is formed as a groove-shaped passage with a substantially rectangular cross-section that opens downward in the vertical direction Vd when applied to the outboard motor A, and extends horizontally Hd from the discharge port 23a that opens upward in the vertical direction Vd defined at its downstream end to the pump chamber discharge port 23b at the other end facing the pump housing recess 11.

[0044] As shown in Figure 4, the joining surface 27 is a flat surface in a direction perpendicular to the axis S so as to be joined to the joining surface 17 of the housing body 10 from the axial direction S. In addition, the joining surface 27 has two positioning holes h formed in opposing regions around the pump housing recess 11 for fitting the positioning pin P of the housing body 10. Furthermore, the joining surface 27 defines a thrust surface 27a in the region around the bearing hole 28 that receives the other end faces 42, 52 of the inner rotor 40 and outer rotor 50.

[0045] As shown in Figures 4 and 9, the bearing hole 28 is formed in a cylindrical shape with an axis S in the region facing the pump housing recess 11, in order to rotatably support the intermediate portion 32 of the rotating shaft 30. The three circular holes 29a are formed in opposing regions around the pump housing recess 11 and in the region of the joint surface 27, so as to allow screws b to pass through which the housing cover 20 is connected to the housing body 10. The five through holes 29b are formed in the area of ​​the joint surface 27 to allow bolts (not shown) to be inserted to connect the housing H (housing body 10 and housing cover 20) to the engine body 6.

[0046] The rotating shaft 30 is formed in a cylindrical shape extending in the axial direction S using a steel material or the like. As shown in Figure 9, one end 31 is fitted into the bearing hole 18 of the housing body 10, and the intermediate portion 32 is fitted into the bearing hole 28 of the housing cover 20, thereby supporting the housing H so as to be rotatable around the axial direction S. Furthermore, the rotating shaft 30 is assembled so that the fitting portion 33 between one end 31 and the intermediate portion 32 is fitted into the fitting hole 43 of the inner rotor 40, and rotates integrally with the inner rotor 40 via a lock pin Lp. In addition, the rotating shaft 30 has a connecting portion 34 at the other end to which one of the gears of the gear train 3 is connected.

[0047] As shown in Figures 3, 7, and 8, the pump element Pe is positioned in the pump housing recess 11 of the housing body 10 and defines a pump chamber Pc that expands and contracts to exert a pumping action on the oil fluid, including the suction stroke, pressurization stroke, and discharge stroke. Here, the inner rotor 40 and outer rotor 50 are trochoidal rotors with a 4-lobe, 5-node trochoidal tooth profile.

[0048] The inner rotor 40 is formed as an external gear with a trochoidal tooth profile using a metal material such as steel or sintered steel, and has one end face 41 that slides against the thrust surface 11a of the housing body 10, the other end face 42 that slides against the thrust surface 27a of the housing cover 20, a fitting hole 43 for fitting the rotating shaft 30, four protrusions 44, and four recesses 45. As shown in Figure 3, the inner rotor 40 rotates integrally with the rotating shaft 30 in the direction of arrow R about the axis S.

[0049] The outer rotor 50 is formed as an internal gear with a tooth profile that can mesh with the inner rotor 40, using a metal material such as steel or sintered steel. It has one end face 51 that slides against the thrust surface 11a of the housing body 10, the other end face 52 that slides against the thrust surface 27a of the housing cover 20, a cylindrical outer circumferential surface 53 centered on the axis S1, five protrusions 54, and five recesses 55. The outer circumferential surface 53 is in slidable contact with the inner circumferential surface 11b of the housing body 10. The five protrusions 54 and five recesses 55 are formed to partially engage with the four protrusions 44 and four recesses 45 of the inner rotor 40.

[0050] The outer rotor 50 rotates in conjunction with the rotation of the inner rotor 40, which rotates around axis S, but at a slower speed than the inner rotor 40, and rotates in the same direction as the inner rotor 40 around axis S1. Furthermore, as the inner rotor 40 and the outer rotor 50 rotate while partially meshing with each other, a pump chamber Pc that expands and contracts between them is defined, and a continuous pumping action including the suction stroke, pressurization, and discharge stroke occurs.

[0051] As shown in Figures 7 and 8, the on / off valve 60 is composed of a valve body 61, a biasing spring 62, a cover member 63, and a stopper pin 64. The valve body 61 is a bottomed cylindrical shape and is slidably inserted into the valve housing portion 14 of the housing body 10. The biasing spring 62 is a compression type coil spring that biases the valve body 61 in the closing direction. The cover member 63 is fitted into the valve housing portion 14 to compress the biasing spring 62 to a predetermined compression range and close the valve. The stopper pin 64 is fitted into the pin hole 14b of the housing body 10 to fix the cover member 63 inside the valve housing portion 14.

[0052] Then, when the discharge pressure of the oil discharged from the pump element Pe exceeds a predetermined level, as shown in Figure 8, the valve body 61 opens the return passage 15 against the biasing force of the biasing spring 62, opening the valve and returning a portion of the oil flowing through the discharge passages 13 and 23 as return fluid to the suction passages 12 and 22 from the return passage 15 (upstream passage 15a, intermediate passage 15c, downstream passage 15b). On the other hand, when the discharge pressure falls below the predetermined level, the valve body 61 closes due to the biasing force of the biasing spring 62, stopping the return of oil. In this configuration, since the on-off valve 60 is built into the housing body 10, the device can be simplified and miniaturized compared to the case where it is located outside the housing H.

[0053] As described above, in the pump device M1 according to the first embodiment, the housing H includes a housing body 10 that opens upward in the vertical direction Vd when applied to the outboard motor A, and a housing cover 20 connected to close the housing body 10 from above. The suction passages 12, 22 and discharge passages 13, 23, which form groove-shaped passages in the housing body 10 and the housing cover 20, form cylindrical suction passages and discharge passages in the housing H. In this way, by making the housing H a two-part structure, the weir portion 16 and the directional wall 16a protruding from the bottom wall 12c in the groove-shaped intake passage 12 can be easily formed integrally as part of the housing body 10.

[0054] Furthermore, the housing H has a directional wall 16a in the intake passage 12 upstream of the opening 15b1 where the return passage 15 opens into the intake passages 12 and 22, which directs the flow of intake oil (intake fluid) drawn into the intake passages 12 and 22 from the intake port 12a away from the flow of return oil (return fluid) returned from the return passage 15.

[0055] In other words, the suction oil drawn in from the intake port 12a flows into the intake passages 12 and 22, as shown by the streamline F1 in Figure 9, where it is redirected in a nearly horizontal direction, directed diagonally upward by the directional wall 16a, and guided mainly along the inner wall surface of the intake passage 22 to the pump chamber intake port 22b at the other end. On the other hand, the return oil returned from the opening 15b1 of the return passage 15 flows out into the reservoir area Sa within the suction passage 12, as shown by the streamline F2 in Figures 8 and 9, and is redirected to flow along the suction passage 12. It is then guided mainly along the bottom wall 12c of the suction passage 12 to the pump chamber suction port 12b at one end. In this way, the intake oil (streamline F1) is deflected upward by the directional wall 16a so as not to collide directly with the return oil (streamline F2), thereby suppressing or preventing flow turbulence caused by collisions between the oils. As a result, pressure loss in the intake passages 12 and 22 can be reduced, and pump efficiency can be improved.

[0056] Furthermore, in addition to defining the reservoir area Sa for accumulating oil, the weir section 16 functions as a directional wall 16a because its upper surface, which forms its outline, is formed as an inclined surface with an upward slope Us toward the downstream side. Compared to the case where the weir section and the directional wall are provided separately, this makes it possible to simplify the structure within the intake passages 12 and 22 and reduce pressure loss. Furthermore, as shown in Figure 9, the opening 15b1 of the return passage 15 is formed to open along the bottom wall 12c of the reservoir area Sa defined downstream of the weir 16 of the suction passage 12 of the housing body 10. This allows the return oil returned from the opening 15b1 of the return passage 15 to flow out into the reservoir area Sa, which is lower than the height of the weir 16. As a result, collisions between the return oil and the suction oil drawn in from the suction port 12a can be more effectively suppressed or prevented.

[0057] Furthermore, since the intake port 12a is formed to open downward in the vertical direction Vd when used in the outboard motor A, which is the target object, it can vertically draw up the oil in the oil pan 7 located below and change its direction so that it flows along the inner wall surface of the intake passage 22, thereby actively deflecting the flow of the intake oil to the upper side within the intake passages 12 and 22. Furthermore, since the discharge port 23a is formed to open upward in the vertical direction Vd when used in the outboard motor A, which is the target object, the suction pipe (e.g., oil strainer 8) connected to the suction port 12a and the discharge pipe connected to the discharge port 23a can be arranged in the same direction, and the components in the area where the pump device M1 is installed can be concentrated and arranged so that they do not spread out in the lateral direction (horizontally).

[0058] Furthermore, the housing H has pump chamber suction ports on both end faces of the pump element Pe in the direction of the axis S, for drawing oil into the pump chamber Pc of the pump element Pe. Specifically, the pump chamber inlet includes a one-end pump chamber inlet 12b formed at the downstream end of the suction passage 12 of the housing body 10 so as to face one end face 41, 51 of the pump element Pe, and a other-end pump chamber inlet 22b formed at the downstream end of the suction passage 22 of the housing cover 20 so as to face the other end face 42, 52 of the pump element Pe. Therefore, while suppressing collisions between the intake oil (streamline F1) and the return oil (streamline F2), the intake oil (streamline F1) can be actively guided to the intake port 22b of the other end of the pump chamber, and the return oil (streamline F2) can be actively guided to the intake port 12b of the one end of the pump chamber. This suppresses pressure loss within the intake passages 12 and 22, and in particular prevents the occurrence of cavitation at high rotational speeds.

[0059] Furthermore, as shown in Figures 3, 4, and 7, the housing H is formed such that the suction passages 12, 22 and the discharge passages 13, 23 are arranged in a V-shape with the pump element Pe as the boundary. The housing body 10 is formed to include a valve housing section 14 that houses the on / off valve 60 and a return passage 15 in the region sandwiched between the suction passage 12 and the discharge passage 13. This makes it possible to achieve component consolidation, narrowing of the width in the plane direction perpendicular to the axis S, thinning in the direction of the axis S, and miniaturization of the entire device.

[0060] Next, we will briefly explain the operation of the pump device M1 applied to the internal combustion engine E mounted on outboard motor A. When the internal combustion engine E is started, the inner rotor 40 rotates in the direction of arrow R via the gear train 3 and the rotating shaft 30, causing the outer rotor 50 to rotate in the same direction in conjunction, and a pumping action is generated by the expansion and contraction of the pump chamber Pc. The oil that flows in from the intake port 12a then flows through the intake passages 12 and 22 and is drawn into the pump chamber Pc from the pump chamber intake ports (one-end pump chamber intake 12b and the other-end pump chamber intake port 22b) located on both ends of the pump element Pe. Then, due to the pumping action of the pump element Pe, the pressurized oil is pushed into the discharge passages 13 and 23 from the pump chamber discharge ports (one end pump chamber discharge port 13b and the other end pump chamber discharge port 23b) located on both ends of the pump element Pe.

[0061] Here, when the pressure of the pressurized oil is below a predetermined level, the on-off valve 60 is in the closed state. Therefore, as shown in Figure 7, the pressurized oil is discharged from the discharge port 23a without passing through the return passage 15 and supplied to the supply destination in the internal combustion engine E. In this flow state, since no return oil flows into the intake passages 12 and 22 from the return passage 15, the intake oil that flows in from the intake port 12a flows towards the pump chamber Pc without its flow being disturbed.

[0062] On the other hand, when the pressure of the pressurized oil exceeds a predetermined level, the on / off valve 60 opens. Therefore, as shown in Figures 8 and 9, the pressurized oil is discharged from the discharge port 23a and supplied to the supply destination in the internal combustion engine E, and a portion of it is returned to the intake passages 12 and 22 through the return passage 15 (upstream passage 15a, intermediate passage 15c, downstream passage 15b). In this flow state, the return oil returned from the return passage 15 to the intake passages 12 and 22 actively flows mainly into the reservoir area Sa defined behind the weir 16, then changes direction to face the intake passage 12 and flows along the bottom wall 12c, and flows into the pump chamber Pc from the pump chamber intake port 12b at one end.

[0063] Furthermore, the suction oil flowing in from the intake port 12a is directed diagonally upward by the directional wall 16a, and flows mainly along the inner wall surface and inclined surface 22a of the intake passage 22, and flows into the pump chamber Pc from the pump chamber intake port 22b on the other end. In this way, the flow of suction oil drawn into the suction passages 12 and 22 from the suction port 12a is directed by the directional wall 16a so as to deviate from the flow of return oil returned from the return passage 15. As a result, direct collision between the intake oil and the return oil is suppressed or prevented, turbulence in the oil flow and pressure loss are reduced, and pump efficiency is improved.

[0064] As described above, the pump device M1 according to the first embodiment can achieve structural simplification, reduction in the number of parts, and cost reduction, while suppressing fluid flow turbulence and pressure loss, thereby improving pump efficiency.

[0065] Figures 10 and 11 show a pump device M2 according to a second embodiment of the present invention. Except for changing the housing body 10 of the first embodiment to a housing body 110, the configuration is the same as that of the first embodiment. Components identical to those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted. The pump device M2 includes a housing body 110 and a housing cover 20 as the housing H, a rotating shaft 30 centered on axis S, an inner rotor 40 and an outer rotor 50 as the pump elements Pe, an on / off valve 60, and screws b for fastening the housing cover 20 to the housing body 10.

[0066] The housing body 110 includes a pump housing recess 11, an intake passage 12, a discharge passage 13, a valve housing 14, a return passage 115, a weir 16 that forms a directional wall 16a, a joint surface 17, a bearing hole 18, three screw holes 19a, and five through holes 19b.

[0067] The return passage 115 is formed by an upstream passage 15a, a downstream passage 115b which is a groove-shaped passage with a substantially rectangular cross-section that opens upward in the vertical direction Vd, and an intermediate passage 15c which is defined between the upstream passage 15a and the downstream passage 115b by a part of the valve housing 14. The downstream passage 115b of the return passage 115 extends diagonally downstream from a position perpendicular to the intake passage 12 (the position shown in Figure 8) and opens. Furthermore, the opening 115b1 of the downstream passage 115b is formed to follow the bottom wall 12c of the intake passage 12 located downstream of the weir 16, that is, the bottom wall 12c of the reservoir area Sa.

[0068] According to the pump device M2 of the second embodiment, the return oil returned from the return passage 115 flows diagonally downstream toward the intake passages 12 and 22 and merges with them, as shown in Figure 11. Therefore, collision between the return oil and the intake oil drawn in from the intake port 12a can be suppressed, as in the first embodiment, and collision between the return oil and the inner wall surface of the intake passages 12 and 22 can also be suppressed.

[0069] In other words, the intake oil (streamline F1) is deflected upward by the directional wall 16a so as not to directly collide with the return oil (streamline F2), and the return oil (streamline F2) flows smoothly into the intake passages 12 and 22, thereby suppressing or preventing flow turbulence caused by collisions between the oils. As a result, the pressure loss in the intake passages 12 and 22 can be reduced compared to the pump device M1 of the first embodiment, and the pump efficiency can be improved.

[0070] As described above, the pump device M2 according to the second embodiment can achieve structural simplification, reduction in the number of parts, and cost reduction, while suppressing fluid flow turbulence and pressure loss, thereby improving pump efficiency.

[0071] Figures 12 to 14 show a pump device M3 according to the third embodiment of the present invention. It has the same configuration as the second embodiment except that the housing body 110 of the second embodiment has been changed to a housing body 210. Components identical to those of the first and second embodiments described above are denoted by the same reference numerals and their descriptions are omitted. The pump device M3 includes a housing body 210 and a housing cover 20 as the housing H, a rotating shaft 30 centered on axis S, an inner rotor 40 and an outer rotor 50 as the pump elements Pe, an on / off valve 60, and screws b for fastening the housing cover 20 to the housing body 10.

[0072] The housing body 210 includes a pump housing recess 11, an intake passage 12, a discharge passage 13, a valve housing 14, a return passage 115, a weir 16 that forms a directional wall 16a, a joint surface 17, a bearing hole 18, three screw holes 19a, five through holes 19b, and a flow straightening wall 211.

[0073] The rectifying wall 211 protrudes from the bottom wall 12c of the reservoir region Sa in the axial direction S and is formed as a roughly rectangular flat plate that is elongated in the direction of extension of the intake passage 12, in order to rectify the return oil returned from the downstream passage 115b of the return passage 115 so that it flows along the intake passage 12 in a predetermined region including the opening 115b1 where the downstream passage 115b of the return passage 115 opens to the intake passage 12.

[0074] The rectifying wall 211 then forces the return oil returned from the return passage 115 (downstream passage 115b) to change direction toward the downstream side of the intake passage 12. This isolates the return oil from the intake oil drawn into the intake passages 12 and 22 from the intake port 12a, thereby more effectively suppressing collisions between the two oils.

[0075] In other words, the intake oil (streamline F1) is deflected upward by the directional wall 16a so as not to collide directly with the return oil (streamline F2), and the return oil (streamline F2) flows smoothly into the intake passages 12 and 22 and is straightened by the straightening wall 221, thereby further suppressing or preventing flow turbulence caused by collisions between oils. As a result, the pressure loss in the intake passages 12 and 22 can be reduced compared to the pump device M2 of the second embodiment, and the pump efficiency can be improved.

[0076] Furthermore, the housing H is made into a two-part structure consisting of a housing body 210 and a housing cover 20, and the rectifying wall 211 is formed to protrude in the axial direction S from the bottom wall 12c of the intake passage 12 of the housing body 210, similar to the weir 16. In this way, by providing a flow straightening wall 211 protruding from the bottom wall 12c of the groove-shaped intake passage 12 in the housing body 210, the weir 16, the directional wall 16a, and the flow straightening wall 211 can be easily formed integrally as part of the housing body 210.

[0077] As described above, the pump device M3 according to the third embodiment can achieve structural simplification, reduction in the number of parts, and cost reduction, while suppressing fluid flow turbulence and pressure loss, thereby improving pump efficiency.

[0078] Figures 15 to 18 show experimental results of simulations of fluid flow in pump devices without a weir and directional wall as comparative examples, and pump devices M1, M2, and M3 according to the first to third embodiments, which were modeled for fluid flow analysis.

[0079] The results show that, in the comparative example, as shown in Figure 15, the intake fluid and return fluid collide violently, and vortex flow is generated in the areas where the streamlines overlap and appear black. In the first embodiment (weir section 16 and directional wall 16a), as shown in Figure 16, the directional wall 16a directs the intake fluid to flow diagonally upward on the downstream side, resulting in gentler collisions between fluids compared to the comparative example. In the second embodiment (where the weir section 16, the directional wall 16a, and the downstream passage 115b of the return passage 115 are open toward the downstream side), as shown in Figure 17, the return fluid flows smoothly along the intake passage 12, resulting in less collision between fluids than in the first embodiment. In the third embodiment (weir section 16, directional wall 16a, downstream passage 115b of the return passage 115 opening toward the downstream side, and straightening wall 211), as shown in Figure 18, the return fluid is straightened by the straightening wall 211 so that it flows along the intake passage 12, resulting in a smoother flow and less collision between fluids compared to the second embodiment.

[0080] Figure 19 is a graph showing the pressure loss obtained in the simulation experimental results shown in Figures 15 to 18. Note that the pressure loss is the pressure P at the upstream end of the intake passages 12 and 22. in (kPa) to the pressure P at the downstream end out Subtracting (kPa), P in -P out The value ΔP is used to represent the value of the comparative example, ΔP0, and the values ​​in the first to third embodiments are expressed as ratios to ΔP0. According to this experiment, the pressure loss in the first embodiment is smaller than that of the comparative example, the pressure loss in the second embodiment is smaller than that of the first embodiment, and the pressure loss in the third embodiment is smaller than that of the second embodiment.

[0081] As described above, by providing a directional wall 16a in the weir section 16 that directs the flow of suction fluid drawn into the suction passages 12 and 22 from the suction port 12a away from the flow of return fluid returned from the return passage 15, turbulence in the fluid flow and pressure loss can be suppressed, and therefore, pump efficiency can be improved. Furthermore, by providing a configuration in which the return passage 15 opens toward the downstream side of the intake passage 12, in addition to the directional wall 16a, and by providing a flow straightening wall 211, turbulence in the fluid flow and pressure loss can be further suppressed, and therefore, the pump efficiency can be further improved.

[0082] In the above embodiment, a directional wall 16a forming an inclined surface on the upper surface of a weir 16 protruding from the bottom wall 12c of the intake passage 12 was shown as a directional wall provided in the housing. However, it is not limited to this, and other forms of directional walls may be used as long as they direct the flow of intake fluid drawn into the intake passage from the intake port away from the flow of return fluid returned from the return passage.

[0083] In the above embodiment, a housing H consisting of housing bodies 10, 110, 210 and a housing cover 20 was shown as the housing, but it is not limited to this, and other forms or segmented housings may be adopted as long as they can be provided with directional walls, weirs, return passages and flow straightening walls.

[0084] In the above embodiment, an outboard motor A was shown as the object to which the pump device of the present invention is applied, but it is not limited to this, and may be applied to other fluid circulation or supply devices, or other objects having a configuration structure.

[0085] As described above, the pump device of the present invention can achieve structural simplification, reduction of the number of parts, and cost reduction while suppressing fluid flow turbulence and pressure loss, thereby improving pump efficiency. Therefore, it is not only applicable to internal combustion engines mounted on outboard motors, but is also useful for vehicles equipped with other engines, or other devices that require the pumping of hydraulic oil or lubricating oil. [Explanation of symbols]

[0086] A. Outboard motor (Applicable object) Vd Vertical direction hd horizontal E Internal combustion engine H Housing 10 Housing body (housing) 11 Pump housing recess 12 Suction passage (groove passage) 12a Inlet 12b One end pump chamber inlet (pump chamber inlet) 13 Discharge passage (groove passage) 13b One end pump chamber discharge port 14 Valve housing 15 Return passage 15a Upstream passage (return passage, grooved passage) 15b Downstream passage (return passage, grooved passage) 15b1 Opening of the return passage 15c Intermediate passage (return passage) 16 Weir 16a Directional wall (inclined surface with an upward slope) 20 Housing Cover (Housing) 22 Suction passage (groove passage) 22a Slope 22b One end pump chamber inlet (pump chamber inlet) 23 Discharge passage (groove passage) 23a Discharge port 23b Other end pump chamber discharge port 30 Rotation axis S axis Pe pump element PC Pump Room 40 Inner rotor (pump element) 50 Outer rotor (pump element) 60 Shut-off valves 110 Housing body (housing) 115 Return passage 115b Downstream passage (return passage, grooved passage) 115b1 opening 210 Housing body (housing) 211 Rectification wall

Claims

1. A housing having an intake passage defining an intake port at its upstream end, a discharge passage defining an outlet at its downstream end, and a return passage that returns a portion of the fluid flowing through the discharge passage back to the middle of the intake passage, A pump element housed in the aforementioned housing rotates around a predetermined axis to draw in, pressurize, and discharge fluid, The system includes an on / off valve for opening and closing the aforementioned return passage, The housing has a weir that protrudes from the bottom wall of the intake passage and defines a reservoir area in the intake passage upstream of the opening where the return passage opens to the intake passage, where fluid is accumulated in the area including the opening, and a directional wall that directs the flow of intake fluid drawn into the intake passage from the intake port away from the flow of return fluid returned from the return passage. The weir section includes an inclined surface that slopes upward toward the downstream side in order to define the directional wall. A pump device characterized by the following features.

2. The opening of the return passage is formed along the bottom wall of the reservoir area. The pump device according to feature 1.

3. The return passage opens downstream from a position perpendicular to the intake passage. The pump device according to claim 1 or 2.

4. The housing has a flow straightening wall protruding from the bottom wall of the reservoir region in a predetermined region including an opening in which the return passage opens to the intake passage, in order to straighten the return fluid returned from the return passage so that it flows along the intake passage. A pump device according to any one of features 1 to 3.

5. The aforementioned intake port opens vertically downward when applied to the object being worked on. A pump device according to any one of features 1 to 4.

6. The discharge port opens upward in the vertical direction in the usage state. The pump device according to feature 5.

7. The housing includes, in the usage state, a housing body that opens upward in the vertical direction, and a housing cover connected to close the housing body from above. The pump device according to claim 5 or 6, characterized by the features described herein.

8. The housing body includes a pump housing recess opening vertically upward to accommodate the pump element, a groove-shaped passage opening vertically upward to define a portion of the suction passage, the discharge passage, and the return passage, and a weir formed in the groove-shaped passage. The pump device according to feature 7.

9. The housing cover includes a groove-shaped passage that opens downward in the vertical direction in order to define a portion of the intake passage and the discharge passage. The pump device according to feature 8.

10. The housing has pump chamber inlet ports on both end faces of the pump element in the axial direction for drawing fluid into the pump chamber of the pump element. The pump device according to feature 9.

11. The pump chamber inlet includes a one-end pump chamber inlet formed at the downstream end of the suction passage of the housing body so as to face one end face of the pump element, and a other-end pump chamber inlet formed at the downstream end of the suction passage of the housing cover so as to face the other end face of the pump element. The pump device according to feature 10.

12. The intake passage of the housing cover includes an inclined surface that is inclined in the same direction as the inclined surface of the weir formed in the housing body. The pump device according to feature 11.

13. The housing is formed such that the suction passage and the discharge passage are arranged in a V-shape with respect to the pump element. A pump device according to any one of features 1 to 12.

14. The housing includes a valve housing for housing the on / off valve and a return passage in the region between the intake passage and the discharge passage. The pump device according to feature 13.

15. The pump element includes an inner rotor that rotates integrally with a rotating shaft that is rotatably supported in relation to the housing around the axis, and an outer rotor that rotates in conjunction with the inner rotor. A pump device according to any one of features 1 to 14.

16. The inner rotor and the outer rotor are trochoidal rotors having a trochoidal tooth profile. The pump device according to feature 15.

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