oil pump

Abstract

The present invention is not likely to cause a deviation in the oil flow rate at one of the two suction ports, and can suppress the occurrence of cavitation. The oil pump includes: a shaft member; an inner rotor that rotates integrally with the shaft member; an outer rotor that rotates as the inner rotor rotates, and forms a rotor chamber between the inner rotor and the outer rotor for sucking oil from a suction passage and discharging the oil toward a discharge passage; a main body member that has a concave housing chamber for housing the inner rotor and the outer rotor in a rotatable manner around the shaft; and a cover member that has at least a part of the suction passage and is mounted to close the housing chamber. The rotor chamber has first and second suction ports through which the oil sucked from the suction passage into the rotor chamber respectively passes. The oil pump has a rectifying member that branches the suction passage from a main passage to the first suction port side and the second suction port side, and rectifies the oil guided from the main passage to the first and second suction ports respectively.

Description

Technical Field

[0001] The present invention relates to an oil pump. Background Art

[0002] Currently, an oil pump mounted on a vehicle is known (for example, Patent Document 1). The oil pump described in Patent Document 1 is driven by an engine of the vehicle, sucks engine oil from an oil pan, and supplies it to a drive system such as a transmission. The oil pump includes: a shaft member that rotates by being driven by the engine; an inner rotor that rotates integrally with the shaft member; and an outer rotor that meshes with the inner rotor in an eccentric state. The inner rotor has a plurality of external teeth. The outer rotor is disposed on the outer peripheral side of the inner rotor, meshes with the inner rotor in an eccentric state, and has a plurality of internal teeth different in number from the external teeth of the inner rotor. The inner rotor and the outer rotor are accommodated in a concave accommodation chamber formed in a main body member so as to be rotatable about the axis. The accommodation chamber of the main body member is closed by a cover member attached to the main body member.

[0003] Regarding the above oil pump, when the engine is driven, the shaft member and the inner rotor rotate integrally with each other, and the outer rotor rotates relative to the inner rotor in an eccentric state. When such rotation occurs, the volumes of a plurality of rotor chambers formed between the inner rotor and the outer rotor sequentially and repeatedly change in a shrinking and expanding manner, thereby sucking engine oil from a storage portion into the rotor chambers based on a negative pressure action, and pumping the engine oil from the rotor chambers to the drive system based on a compression action.

[0004] In addition, regarding the above oil pump, the rotor chamber has two suction ports. The two suction ports are provided to face each other in the axial direction at both axial ends of the rotor chamber. Branch passages branched from a suction passage communicate with the respective suction ports, and the engine oil entering the branch passages from the suction passage is guided.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-166372

[0006] However, regarding the oil pump described in Patent Document 1 above, the flow of the engine oil branched from the suction passage and guided to each suction port is not rectified, so that the flow rate of the engine oil guided to the rotor chamber sometimes tends to be in a state where it passes through one suction port side. If such a deviation occurs, a pressure difference is generated due to a difference in the flow velocity of the engine oil introduced into the two suction ports, so that cavitation (bubbles), which is a cause of erosion, is likely to occur. Summary of the Invention

[0007] The present invention has been made in view of this point, and an object thereof is to provide an oil pump that is less likely to cause a deviation in the oil flow rate to one of the two suction ports and can suppress the occurrence of cavitation.

[0008] One aspect of the present invention is an oil pump having: a shaft member that rotates by the drive of a drive source; an inner rotor having external teeth that rotates integrally with the shaft member; an outer rotor having internal teeth that mesh with the external teeth and rotates as the inner rotor rotates, and a rotor chamber that forms between the inner rotor and the outer rotor for sucking engine oil from a suction passage and discharging the engine oil toward a discharge passage; a main body member having a concave housing chamber that houses the inner rotor and the outer rotor so as to be rotatable about an axis; and a cover member having at least a part of the suction passage and mounted to close the housing chamber, the rotor chamber having a first suction port and a second suction port through which the engine oil sucked from the suction passage into the rotor chamber passes, the oil pump having a rectifying member that branches the suction passage from a main passage to the first suction port side and the second suction port side and rectifies the engine oil guided from the main passage to the first suction port and the engine oil guided from the main passage to the second suction port.

[0009] According to this structure, it is possible to avoid a state in which the flow rate of the engine oil guided from the suction passage to the rotor chamber is biased toward either one of the two suction ports. Therefore, it is difficult for a deviation in the engine oil flow rate to occur in one of the two suction ports, and the occurrence of cavitation can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a front view of the oil pump according to an embodiment.

[0011] Figure 2 is a side view of the oil pump of the present embodiment.

[0012] Figure 3 is a rear view of the oil pump of the present embodiment.

[0013] Figure 4 is a bottom view of the oil pump of the present embodiment.

[0014] Figure 5 is a Figure 1 cross-sectional view of the oil pump of the present embodiment taken along the line V-V shown.

[0015] Figure 6 is an exploded perspective view of the oil pump of the present embodiment viewed from the front side.

[0016] Figure 7 is an exploded perspective view of the oil pump of the present embodiment viewed from the back side.

[0017] Figure 8 is a rear view of the main body member of the oil pump of the present embodiment.

[0018] Figure 9This is the front view of the cover member of the oil pump according to the present embodiment.

[0019] Figure 10 This is an oblique view showing the state in which the inner rotor and the outer rotor are housed in the housing chamber of the main body member of the oil pump according to the present embodiment.

[0020] Figure 11 This is an oblique view showing the state in which the plate member is assembled to the cover member of the oil pump according to the present embodiment. Detailed Embodiment

[0021] Utilize Figures 1 to 11 To describe the detailed embodiment of the oil pump according to the present invention.

[0022] The oil pump 1 according to one embodiment is a cycloidal internal gear pump that pumps the engine oil sucked from the suction port to the discharge port. The oil pump 1 is mounted on a vehicle or the like, for example, and supplies the engine oil to a drive system such as a transmission for cooling and lubrication. As Figures 1 to 4 shown, the entire oil pump 1 is formed in a block shape.

[0023] As Figures 5 to 7 shown, the oil pump 1 includes a shaft member 10, an inner rotor 20, and an outer rotor 30. The shaft member 10 is a shaft member that rotates by being driven by a drive source such as a vehicle engine. The shaft member 10 extends in a rod shape along the axial direction. The inner rotor 20 and the outer rotor 30 are rotating bodies that constitute a cycloid pump. The inner rotor 20 and the outer rotor 30 are each formed of sintered metal (for example, iron-based, copper-iron-based, copper-based, stainless steel-based, etc.).

[0024] The inner rotor 20 is a plate-shaped or columnar member having a plurality of external teeth 21. The external teeth 21 are provided at equal angular intervals on the outer peripheral surface of the inner rotor 20. The number of the external teeth 21 of the inner rotor 20 is a specified number (for example, 4). The inner rotor 20 has a shaft hole 22 that penetrates through the center. The shaft member 10 is inserted into the shaft hole 22 to support and fix the inner rotor 20 to the shaft member 10 at the center. The shaft member 10 is rotatably supported by a main body member 50 described later via a bearing (not shown). The inner rotor 20 rotates integrally with the shaft member 10.

[0025] The outer rotor 30 is a ring-shaped or cylindrical member having a plurality of internal teeth 31. The internal teeth 31 are provided at equal angular intervals on the inner peripheral surface of the outer rotor 30. The number of the internal teeth 31 of the outer rotor 30 is a specified number (for example, 5) that is a predetermined number (for example, one) more than the number of the external teeth 21 of the inner rotor 20.

[0026] The outer rotor 30 has an inner space capable of accommodating the inner rotor 20. The outer rotor 30 is arranged on the outer peripheral side of the inner rotor 20. The inner teeth 31 of the outer rotor 30 mesh with the outer teeth 21 of the inner rotor 20. The inner rotor 20 and the outer rotor 30 are eccentric. That is, the axial center of the inner rotor 20 and the axial center of the outer rotor 30 are arranged at offset positions. The inner rotor 20 and the outer rotor 30 can rotate relative to each other in an eccentric state. The outer rotor 30 rotates as the inner rotor 20 rotates.

[0027] like Figure 5 and Figure 10 As shown, the inner rotor 20 and the outer rotor 30 form a plurality of rotor chambers 40 surrounded by the outer circumferential surface of the inner rotor 20 and the inner circumferential surface of the outer rotor 30. The rotor chamber 40 is a space for sucking oil from the suction passage of the oil pump 1 and discharging the oil toward the discharge passage. The volume of each rotor chamber 40 changes repeatedly in a manner of shrinking and expanding in sequence as the inner rotor 20 and the outer rotor 30 rotate.

[0028] Furthermore, the oil pump 1 includes a body member 50 , a cover member 60 , a filter 70 , and a plate member 80 .

[0029] The main body member 50 is a member that rotatably accommodates the inner rotor 20 and the outer rotor 30. The main body member 50 is formed of a metal such as iron or aluminum. The main body member 50 is a molded body formed by stamping, forging, or die casting, or a processed product further subjected to cutting or grinding.

[0030] like Figure 5 , Figure 7 and Figure 8 As shown, the main body member 50 has an axial hole 51 and a receiving chamber 52. The axial hole 51 is a through hole into which the axial member 10 is inserted. The axial member 10 is supported to be rotatable relative to the main body member 50. The receiving chamber 52 is a substantially cylindrical space that rotatably receives the inner rotor 20 and the outer rotor 30. The receiving chamber 52 is formed in a concave shape surrounded by a bottom wall 52a and a side wall 52b.

[0031] The accommodating chamber 52 is open on the axially opposite side of the bottom wall 52a side. When the inner rotor 20 and the outer rotor 30 are assembled to the main body member 50, they are inserted into the accommodating chamber 52 from the opening side. The inner rotor 20 rotates integrally with the rotation of the shaft member 10. In addition, the outer rotor 30 rotates relative to the main body member 50 with the rotation of the inner rotor 20.

[0032] The cover member 60 is a member that covers the opening of the accommodation chamber 52. The cover member 60 is installed to enclose the accommodation chamber 52. The cover member 60 is formed of a thermoplastic resin or the like. It is preferable that the resin forming the cover member 60 has excellent creep resistance, load resistance, abrasion resistance, etc., and for example, it is a polyphenylene sulfide (PPS) resin, a thermoplastic polyimide resin, or the like. The cover member 60 is formed by injection molding or the like.

[0033] As Figure 5 , Figure 6 and Figure 9 shown, the cover member 60 has a suction passage 61. The suction passage 61 has: an inlet 61a that opens on the side of the oil pan (not shown); and an outlet 61b that opens on the side of the rotor chamber 40. The suction passage 61 is a passage through which engine oil that is introduced from the oil pan side to the inlet 61a and sucked into the rotor chamber 40 via the outlet 61b flows. The inlet 61a and the outlet 61b are provided such that openings are formed in planes orthogonal to each other. For example, as Figure 5 shown, the inlet 61a is formed on the lower surface of the cover member 60, and the outlet 61b is formed on the side surface of the cover member 60.

[0034] The filter 70 is installed on the inlet 61a side of the suction passage 61 by bolt fastening or the like. The filter 70 removes impurities from the engine oil sucked from the oil pan via the suction port 71. The engine oil from which impurities have been removed by the filter 70 is guided to the suction passage 61.

[0035] The suction passage 61 has a main passage 61c, a first branch passage 61d, and a second branch passage 61e. The main passage 61c is provided on the upstream side of the suction passage 61 including the inlet 61a. The first branch passage 61d and the second branch passage 61e are respectively provided on the downstream side of the suction passage 61 including the outlet 61b. The main passage 61c communicates with the first branch passage 61d and also communicates with the second branch passage 61e. The outlet 61b has: a first outlet 61b-1 that opens on the side of the first branch passage 61d; and a second outlet 61b-2 that opens on the side of the second branch passage 61e.

[0036] The cover member 60 has a rectifying member 62. The rectifying member 62 is a member that causes the suction passage 61 to branch into the first branch passage 61d and the second branch passage 61e from the main passage 61c. The rectifying member 62 divides the downstream side of the suction passage 61 into the first branch passage 61d and the second branch passage 61e, and also divides the outlet 61b into the first outlet 61b-1 and the second outlet 61b-2. The rectifying member 62 rectifies the engine oil flowing from the main passage 61c to the first branch passage 61d and the engine oil flowing from the main passage 61c to the second branch passage 61e.

[0037] The rectifying member 62 is formed in a plate shape. The rectifying member 62 is provided integrally with the cover member 60. In addition, the rectifying member 62 can be a member that is formed separately from the cover member 60 and installed on the cover member 60 after formation (for example, fitted into a groove provided in the cover member 60). The rectifying member 62 is disposed near the outlet 61b. The rectifying member 62 extends parallel to the surface of the cover member 60 having the inlet 61a, and extends in a direction orthogonal to the surface of the cover member 60 having the outlet 61b. The engine oil that enters the suction passage 61 from the filter 70 circulates through the main passage 61c and then branches and flows into the first branch passage 61d and the second branch passage 61e that pass through the rectifying member 62.

[0038] The first branch passage 61d communicates with the rotor chamber 40 side at the first outlet 61b-1. The engine oil that enters the first branch passage 61d from the main passage 61c is guided from the first outlet 61b-1 to the rotor chamber 40.

[0039] The main body member 50 has a suction passage 53. The suction passage 53 has: an inlet 53a that opens to the suction passage 61 (specifically, the second branch passage 61e) of the cover member 60; and an outlet 53b that opens to the rotor chamber 40 side. The suction passage 53 is formed to communicate with the rotor chamber 40 in a state where the inner rotor 20 and the outer rotor 30 are housed in the housing chamber 52 of the main body member 50. The suction passage 53 communicates with the second branch passage 61e of the suction passage 61 of the cover member 60 at the inlet 53a and communicates with the rotor chamber 40 at the outlet 53b. The suction passage 53 is a passage through which the engine oil that is introduced from the second outlet 61b-2 of the second branch passage 61e to the inlet 53a and is sucked into the rotor chamber 40 via the outlet 53b flows.

[0040] The suction passage 53 is formed in a space other than the region in the entire housing chamber 52 of the main body member 50 that occupies a radially inner side than the outer peripheral surface of the outer rotor 30 in a state where the outer rotor 30 is housed. That is, the housing chamber 52 includes: a region that occupies a radially inner side than the outer peripheral surface of the outer rotor 30 in a state where the outer rotor 30 is housed; and a region occupied by the suction passage 53 in a state where the outer rotor 30 is housed. The suction passage 53 includes: an upstream side space that communicates with the inlet 53a and is formed on the radially outer side of the outer rotor 30 housed in the housing chamber 52; and a downstream side space that communicates with the outlet 53b and is formed on the axially inner side opposite to the opening side of the housing chamber 52 with respect to the outer rotor 30.

[0041] The second branch passage 61e communicates with the inlet 53a of the suction passage 53 at the second outlet 61b-2. And, the suction passage 53 communicates with the rotor chamber 40 at the outlet 53b. The engine oil that enters the second branch passage 61e from the main passage 61c is guided from the second outlet 61b-2 to the suction passage 53, then circulates through the suction passage 53 and is guided to the rotor chamber 40.

[0042] Each rotor chamber 40 has a first suction port 41 and a second suction port 42. The first suction port 41 and the second suction port 42 are ports through which the engine oil guided from the suction passage 61 side of the cover member 60 passes. The first suction port 41 and the second suction port 42 are provided at positions axially spaced apart from the rotor chamber 40, and are provided on both axial sides of the rotor chamber 40 and axially opposed to each other.

[0043] In addition, when one axial end face ( Figure 5 the right end face) of the rotor chamber 40 is exposed to the first branch passage 61d of the suction passage 61, the exposed portion becomes the first suction port 41, and when the other axial end face ( Figure 5 the left end face) of the rotor chamber 40 is exposed to the suction passage 53, the exposed portion becomes the second suction port 42.

[0044] The first suction port 41 communicates with the first outlet 61b-1 of the first branch passage 61d. The second suction port 42 communicates with the outlet 53b of the suction passage 53. The engine oil guided from the main passage 61c to the first branch passage 61d is sucked into the rotor chamber 40 through the first suction port 41, and the engine oil that enters the second branch passage 61e from the main passage 61c and is guided to the suction passage 53 is sucked through the second suction port 42.

[0045] The rectifying member 62 rectifies the engine oil as follows: the engine oil guided from the main passage 61c of the suction passage 61 to the first branch passage 61d and guided to the first suction port 41 of the rotor chamber 40; and the engine oil guided from the main passage 61c to the second branch passage 61e and the suction passage 53 and guided to the second suction port 42 of the rotor chamber 40. Specifically, the rectifying member 62 is formed so that the flow rate of the engine oil guided to the first suction port 41 (referred to as the first flow rate) and the flow rate of the engine oil guided to the second suction port 42 (referred to as the second flow rate) are equal.

[0046] The rectifying member 62 divides the first branch passage 61d and the second branch passage 61e so that the cross-sectional areas are equal. That is, the first branch passage 61d and the second branch passage 61e are formed to have equal cross-sectional areas.

[0047] In addition, the "equality" of the above-mentioned engine oil flow rate and the cross-sectional area of the branch passage is not limited to being exactly the same, and may also include a degree that can be regarded as exactly the same. For example, if the flow rate of the engine oil flowing between the first branch passage 61d and the second branch passage 61e has no deviation and the range where cavitation is not likely to occur, it is also included in the range of "equal".

[0048] As described above, the rectifying member 62 is formed in a plate shape. The rectifying member 62 is formed and arranged in such a manner that one axial end face ( Figure 5The right end face) faces the suction passage 61, and the other axial end face ( Figure 5 The left end face) is axially opposed to the axial end face of the outer rotor 30 without interruption from one end to the other in a direction different from the plate thickness direction of the rectifying member 62. Even if the outer rotor 30 rotates about the axis, the other axial end face of the rectifying member 62 always faces the axial end face of the outer rotor 30.

[0049] That is, the rectifying member 62 is formed and arranged in such a way that the radial position of the line segment where the other axial end face of the rectifying member 62 intersects the surface facing radially outward is more radially outward than the radial position of the maximum inner edge portion having the maximum inner diameter (maximum inner diameter) among the inner edge ends of the outer rotor 30 over the entire range of the line segment, and the radial position of the line segment where the other axial end face of the rectifying member 62 intersects the surface facing radially inward is more radially inward than the radial position of the outer edge end of the outer rotor 30 over the entire range of the line segment.

[0050] In addition, the rectifying member 62 may have a plate thickness less than or equal to the radial width of the outer edge end of the outer rotor 30 and the above-mentioned maximum inner edge portion. In this case, the other axial end face of the rectifying member 62 faces the axial end face of the outer rotor 30 in the range from the outer edge end of the outer rotor 30 corresponding to the radial width to the radially inner portion.

[0051] The rectifying member 62 is formed to be bent along the outer shape of the outer rotor 30. Specifically, the rectifying member 62 is formed to extend in an arc shape around the axis center of the shaft member 10.

[0052] The rectifying member 62 is formed such that the other axial end face is coplanar with the surface of the cover member 60 where the outlet 61b of the suction passage 61 is formed. As will be described later, the plate member 80 is interposed between the main body member 50 and the cover member 60. The rectifying member 62 is formed and arranged to form a gap 90 between the other axial end face and the axial end face of the outer rotor 30. In addition, the smaller the gap 90 is in terms of preventing oil from flowing in and out between the first branch passage 61d and the second branch passage 61e, the better, and more preferably it is zero. The gap 90 is set to be less than or equal to the maximum size (e.g., 2 mm) that can prevent oil from flowing in and out between the first branch passage 61d and the second branch passage 61e.

[0053] In addition, the cover member 60 has a discharge passage 63. The discharge passage 63 has: an inlet 63a that opens on the rotor chamber 40 side; and an outlet 63b (refer to Figure 3 ), which opens on the oil supply target side. The discharge passage 63 is a passage through which the oil discharged from the rotor chamber 40 and entering through the inlet 63a flows toward the outlet 63b. The oil flowing through the discharge passage 63 and discharged from the outlet 63b is supplied to the oil supply target.

[0054] The plate member 80 is a plate-shaped member interposed between the main body member 50 and the cover member 60. The plate member 80 is divided to close the opening of the accommodation chamber 52 of the main body member 50. The plate member 80 is provided to raise the rotor chamber 40 to a prescribed high pressure state. Similar to the main body member 50, the plate member 80 is formed of a metal such as iron or aluminum. As Figure 6 , Figure 7 and Figure 11 shown, the plate member 80 has a suction hole 81 and a discharge hole 82.

[0055] The suction hole 81 is a through hole that guides engine oil from the suction passage 61 of the cover member 60 to the rotor chamber 40. In a state where it is interposed between the main body member 50 and the cover member 60, the suction hole 81 communicates with the first outlet 61b-1 of the first branch passage 61d of the suction passage 61 and the first suction port 41 of the rotor chamber 40, and also communicates with the second outlet 61b-2 of the second branch passage 61e of the suction passage 61 and the inlet 53a of the suction passage 53 of the main body member 50.

[0056] The suction hole 81 is formed in a shape that conforms to the shape of the outlet 61b of the suction passage 61. A part of the suction hole 81 (specifically, the part that communicates with the first branch passage 61d and the rotor chamber 40) is formed to extend in an arc around the axis center of the shaft member 10. Another part of the suction hole 81 (specifically, the part that communicates with the second branch passage 61e and the suction passage 53 of the main body member 50) is formed to be continuous with the above-mentioned part of the suction hole 81. The suction passage 61 (specifically, the main passage 61c, the first branch passage 61d, and the second branch passage 61e), the suction hole 81, and the suction passage 53 as a whole constitute a suction passage for sucking engine oil into the rotor chamber 40 (hereinafter, appropriately collectively referred to as the suction passage 43).

[0057] In addition, the discharge hole 82 is a through hole that guides engine oil from the rotor chamber 40 to the discharge passage 63 of the cover member 60. In a state where it is interposed between the main body member 50 and the cover member 60, the discharge hole 82 communicates with the rotor chamber 40 of the rotor chamber 40 and the discharge passage 63. The discharge hole 82 is formed in a shape that conforms to the shape of the inlet 63a of the discharge passage 63. The discharge hole 82 is formed to extend in an arc around the axis center of the shaft member 10. The discharge hole 82 and the discharge passage 63 as a whole constitute a discharge passage for supplying the engine oil discharged from the rotor chamber 40 to an engine oil supply target (hereinafter, appropriately collectively referred to as the discharge passage 44).

[0058] The main body member 50, the plate member 80, and the cover member 60 are fastened to each other by bolt fastening or the like in a state where the shaft member 10 is rotatably supported by the main body member 50 and the inner rotor 20 and the outer rotor 30 are accommodated in the accommodation chamber 52 of the main body member 50. In addition, the main body member 50 is fixed to a vehicle structure (not shown) by bolt fastening or the like.

[0059] Next, the operation of the oil pump 1 will be described.

[0060] In the oil pump 1, if the shaft member 10 rotates, the inner rotor 20 rotates relative to the main body member 50 in accordance with the rotation of the shaft member 10, and the outer rotor 30 rotates relative to the main body member 50 in accordance with the rotation of the inner rotor 20.

[0061] In the rotation of the inner rotor 20 and the outer rotor 30 that constitute the cycloid pump, during the process in which the volume of the rotor chamber 40 increases, the internal pressure of the rotor chamber 40 becomes negative. The rotor chamber 40 communicates with the suction passage 43 at the timing when the internal pressure becomes negative. If such communication is performed, after the engine oil is sucked from the oil pan, passes through the filter 70, and flows through the main passage 61c of the suction passage 61, it is diverted to the path that flows through the first branch passage 61d and the suction hole 81 and is sucked into the rotor chamber 40 via the first suction port 41, and the path that flows through the second branch passage 61e, the suction hole 81, and the suction passage 53 and is sucked into the rotor chamber 40 via the second suction port 42, and is sucked into the rotor chamber 40.

[0062] In addition, in the rotation of the inner rotor 20 and the outer rotor 30, during the process in which the volume of the rotor chamber 40 decreases, the internal pressure of the rotor chamber 40 increases. The rotor chamber 40 communicates with the discharge passage 44 at the timing when the internal pressure increases. If such communication is performed, the engine oil in the rotor chamber 40 is discharged to the discharge passage 63 via the discharge hole 82 and is supplied from the outlet 63b to the oil supply target.

[0063] If the above-described pump action is continuously exerted by the rotation of the inner rotor 20 and the outer rotor 30, the oil pump 1 sucks the engine oil from the oil pan and pumps the engine oil toward the oil supply target. Therefore, with the oil pump 1, the engine oil sucked from the oil pan can be pumped toward the oil supply target.

[0064] In addition, in the oil pump 1, the rotor chamber 40 has two suction ports 41 and 42, and the engine oil sucked into the rotor chamber 40 from the suction passage 61 side passes through the two suction ports 41 and 42. Specifically, a part of the engine oil flowing through the main passage 61c is guided to the first suction port 41 through a path including the first branch passage 61d, and the remaining part of the engine oil is guided to the second suction port 42 through a path including the second branch passage 61e and the suction passage 53.

[0065] According to the structure of the oil pump 1, engine oil can be sucked into the rotor chamber 40 surrounded by the outer peripheral surface of the inner rotor 20 and the inner peripheral surface of the outer rotor 30 from two suction ports 41 and 42. In particular, the two suction ports 41 and 42 are axially opposed to each other on both axial sides of the rotor chamber 40. Therefore, the rotor chamber 40 will not increase in a way that protrudes radially outward, and the maximum flow rate of the engine oil sucked into the rotor chamber 40 can be ensured. Therefore, a small-sized and high-performance oil pump 1 can be achieved.

[0066] In addition, in the oil pump 1, a rectifying member 62 is provided that branches the suction passage 43 toward the first suction port 41 side and the second suction port 42 side. Moreover, the rectifying member 62 rectifies the engine oil guided from the suction passage 43 to the first suction port 41 of the rotor chamber 40 and the engine oil guided from the suction passage 43 to the second suction port 42 of the rotor chamber 40. According to this structure, it is possible to suppress the state in which the flow rate of the engine oil guided from the suction passage 43 to the rotor chamber 40 is biased toward either of the two suction ports 41 and 42.

[0067] In particular, the rectifying member 62 is formed and arranged such that the first flow rate of the engine oil guided to the first suction port 41 is equal to the second flow rate of the engine oil guided to the second suction port 42, and is divided such that the cross-sectional areas of the two branch passages 61d and 61e branched from the main passage 61c of the suction passage 61 are equal. According to this structure, it is possible to substantially equalize the flow rate of the engine oil guided from the main passage 61c of the suction passage 43 to the two branch passages 61d and 61e, and it is possible to make the suction of the engine oil into the rotor chamber 40 via the two suction ports 41 and 42 substantially uniform.

[0068] Therefore, according to the structure of the oil pump 1, it is possible to suppress a difference in the flow velocity of the engine oil introduced into the two suction ports 41 and 42 and suppress the pressure difference between the two suction ports 41 and 42. As a result, it is possible to suppress the occurrence of cavitation, which is the cause of erosion.

[0069] In addition, the above-mentioned rectifying member 62 is formed and arranged such that the other axial end surface of the rectifying member 62 is axially opposed to the axial end surface of the outer rotor 30 without interruption from one end to the other end in a direction different from the plate thickness direction of the rectifying member 62 (specifically, the circumferential direction).

[0070] According to the structure of the oil pump 1, a situation where at least a part of the other axial end face of the rectifying member 62 from one circumferential end to the other circumferential end is located radially outside the outer edge end of the outer rotor 30 in its entire plate thickness direction will not occur. Therefore, it is possible to prevent the first branch passage 61d from directly communicating with the suction passage 53 of the main body member 50. In addition, a situation where at least a part of the other axial end face of the rectifying member 62 from one end to the other end in a direction different from the plate thickness direction of the rectifying member 62 faces the rotor chamber 40 in its entire plate thickness direction will not occur. Therefore, it is possible to prevent the second branch passage 61e from directly communicating with the first suction port 41.

[0071] Therefore, it is possible to prevent the engine oil temporarily shunted to the first branch passage 61d side and the second branch passage 61e side at one axial end side of the rectifying member 62 from being sucked into the suction ports 42, 41 different from the desired suction ports 41, 42 of the rotor chamber 40 at the other axial end side of the rectifying member 62.

[0072] In addition, the rectifying member 62 is formed and arranged in such a manner that the other axial end face of the rectifying member 62 is formed coplanar with the face of the cover member 60 where the outlet 61b of the suction passage 61 is formed, and a gap 90 is formed between the other axial end face of the rectifying member 62 and the axial end face of the outer rotor 30. The gap 90 is set to a size that can prevent the engine oil from flowing in and out between the first branch passage 61d and the second branch passage 61e. Therefore, regarding the structure of the oil pump 1, it is possible to prevent the engine oil temporarily shunted to the first branch passage 61d side and the second branch passage 61e side at one axial end side of the rectifying member 62 from being sucked into the suction ports 42, 41 different from the desired suction ports 41, 42 of the rotor chamber 40 via the gap 90 at the other axial end side of the rectifying member 62.

[0073] In addition, the rectifying member 62 is formed to be bent along the outer shape of the outer rotor 30. In this structure, the regions where the first branch passage 61d communicates with the rotor chamber 40 and the region where the second branch passage 61e communicates with the suction passage 53 can be expanded in the direction around the axis of the shaft member 10 respectively. Therefore, it is possible to increase the flow path cross-sectional area of the suction passage 43 and increase the maximum flow rate of the engine oil sucked from the suction passage 43 into the rotor chamber 40.

[0074] Thus, the oil pump 1 has the following configuration, that is, the rectifying member 62 is formed such that the other axial end face of the rectifying member 62 is axially opposed to the axial end face of the outer rotor 30 without interruption from one circumferential end to the other circumferential end, and is formed to be curved along the outer shape of the outer rotor 30. According to this configuration, it is possible to prevent the engine oil that has branched off to the first branch passage 61d side and the second branch passage 61e side from converging on the other branch passages 61e and 61d sides and being sucked into the suction ports 42 and 41 different from the desired suction ports 41 and 42, and it is possible to increase the maximum flow rate of the engine oil sucked from the suction passage 43 into the rotor chamber 40.

[0075] However, in the above-described embodiment, the rectifying member 62 is formed and arranged in such a manner that the other axial end face of the rectifying member 62 is coplanar with the face of the cover member 60 where the outlet 61b of the suction passage 61 is formed, and a gap 90 is formed between the other axial end face of the rectifying member 62 and the axial end face of the outer rotor 30. However, the present invention is not limited to this, and the rectifying member 62 may also be formed and arranged in such a manner that the other axial end face of the rectifying member 62 is formed to protrude toward the main body member 50 from the face of the cover member 60 where the outlet 61b of the suction passage 61 is formed, and the gap 90 formed between the other axial end face of the rectifying member 62 and the axial end face of the outer rotor 30 is zero. According to the structure of such a modified form, it is possible to reliably prevent the engine oil that has branched off to the first branch passage 61d side and the second branch passage 61e side from converging on the other branch passages 61e and 61d sides and being sucked into the suction ports 42 and 41 different from the desired suction ports 41 and 42.

[0076] In addition, in the above-described embodiment, the rectifying member 62 that branches off from the main passage 61c of the cover member 60 to the first branch passage 61d and the second branch passage 61e is provided integrally with the cover member 60. However, the present invention is not limited to this, and the rectifying member that branches off from the main passage 61c of the cover member 60 to the first branch passage 61d and the second branch passage 61e may also be provided separately from the cover member 60. For example, the rectifying member may be provided on the plate member 80. In this modified form, the rectifying member may be formed to protrude in such a manner as to enter the suction passage 61 from the plate surface of the plate-shaped plate member 80 and divide into the first branch passage 61d and the second branch passage 61e.

[0077] Furthermore, the present invention is not limited to the above-described embodiments and modified forms, and various changes may be made without departing from the gist of the present invention.

[0078] In addition, this application claims priority based on Japanese Patent Application No. 2021-089642 filed in Japan on May 27, 2021, and incorporates by reference all of the descriptions recited in the Japanese application.

[0079] Description of Reference Numerals

[0080] 1: oil pump, 10: shaft component, 20: inner rotor, 30: outer rotor, 40: rotor chamber, 41: first suction port, 42: second suction port, 43: suction passage, 44: discharge passage, 50: main body component, 52: accommodation chamber, 53: suction path, 60: cover component, 61: suction path, 61c: main path, 61d: first branch path, 61e: second branch path, 62: rectifying component, 63: discharge path, 70: filter, 80: plate component, 81: suction hole, 82: discharge hole, 90: clearance.

Claims

1. An oil pump, wherein, the oil pump has: a shaft member that rotates by the drive of a drive source; an inner rotor having external teeth and rotating integrally with the shaft member; an outer rotor having internal teeth that mesh with the external teeth, rotating as the inner rotor rotates, and forming a rotor chamber between the inner rotor and the outer rotor for sucking engine oil from a suction passage and discharging the engine oil toward a discharge passage; a main body member having a concave receiving chamber for receiving the inner rotor and the outer rotor so as to be rotatable about an axis; and a cover member having at least a part of the suction passage and mounted to close the receiving chamber, the rotor chamber having a first suction port and a second suction port through which the engine oil sucked from the suction passage into the rotor chamber respectively passes, the oil pump having a rectifying member that branches the suction passage from a main passage to the first suction port side and the second suction port side and rectifies the engine oil guided from the main passage to the first suction port and the engine oil guided from the main passage to the second suction port, the rectifying member being formed and arranged such that the axial end face of the rectifying member faces the axial end face of the outer rotor without interruption in the axial direction from one end to the other end in a direction different from the plate thickness direction of the rectifying member.

2. The oil pump according to claim 1, wherein, the rectifying member is formed to be bent along the outer shape of the outer rotor.

3. The oil pump according to claim 1, wherein, the rectifying member is formed and arranged such that a gap of less than or equal to 2 mm is formed between the axial end face of the rectifying member and the axial end face of the outer rotor.

4. The oil pump according to claim 1, wherein, the rectifying member is formed and arranged such that a first flow rate of the engine oil guided from the main passage to the first suction port and a second flow rate of the engine oil guided from the main passage to the second suction port are equal.

5. The oil pump according to claim 1, wherein, the first suction port and the second suction port are arranged to face each other in the axial direction at both axial ends of the rotor chamber, the cover member has: a first branch passage provided on the downstream side of the main passage, communicating with the outlet of the main passage, and guiding the engine oil to the first suction port; and a second branch passage provided on the downstream side of the main passage, communicating with the outlet of the main passage, and guiding the engine oil to the second suction port, the main body member has a suction passage communicating with the second branch passage and guiding the engine oil to the second suction port.

6. The oil pump according to claim 5, wherein, the rectifying member divides the first branch passage and the second branch passage such that the sectional areas are equal.

7. The oil pump according to claim 1, wherein, the rectifying member and the cover member are provided integrally.

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