JP6129483B2 - Oil pump - Google Patents

Description

  The present invention relates to an oil pump that sucks and discharges oil (lubricating oil) of an internal combustion engine (engine) and the like, and particularly includes an inner rotor and an outer rotor of a trochoid type, an internal gear (involute) type or the like. It relates to an oil pump.

The engine oil pump includes a housing, a rotating shaft (drive shaft) supported by the housing, an inner rotor that is rotated by the rotating shaft and has external teeth, an inner tooth that engages with the outer teeth of the inner rotor, and an inner rotor. Equipped with an outer rotor that delimits a pump chamber with a change in volume in cooperation with the rotor, etc., and a suction port for sucking oil, a discharge port for discharging oil, and an air vent for discharging air mixed in the oil to the housing Holes (bubble discharge port, deaeration port), etc. are provided, the inner rotor is rotated via the rotating shaft, the pump action is obtained by rotating the outer rotor in conjunction with the rotation of the inner rotor, and the oil from the suction port Inhale and pressurize, discharge the pressurized oil from the discharge port, and discharge air (bubbles) mixed in the oil from the air vent hole It is known those as in (for example, see Patent Document 1, Patent Document 2, Patent Document 3, etc.).
By the way, since this oil pump is a one-stage booster type that includes only one set of pump units including an inner rotor and an outer rotor, there is a possibility that the required discharge pressure may not be satisfied depending on the applied engine.

On the other hand, a fluid pump that can ensure a high discharge pressure includes a housing, a rotary shaft (drive shaft) supported by the housing, a front pump unit and a rear pump unit arranged in the axial direction of the rotary shaft. , One or two sets of inner rotors (inner gears) and outer rotors (outer gears), and the rear pump unit is composed of a pair of inner rotors (inner gears) and outer rotors (outer gears). Set the discharge amount of the pump unit and the discharge amount of the rear pump to be the same, and provide one or two suction ports for sucking oil from the outside and one discharge port for discharging oil to the outside in the housing The inner rotor (inner gear) is rotated by rotating the front and rear inner rotors (inner gears) via the rotating shaft. The first stage pump action by the former stage pump unit and the second stage pump action by the latter stage pump unit are obtained by rotating the outer rotor (outer gear) of the former stage and the latter stage in conjunction with the rotation of the A fluid is known in which fluid is sucked and pressurized from a discharge port, and fluid whose pressure is increased (pressurized) twice from a discharge port is known (for example, see Patent Document 4).
By the way, in this two-stage booster type fluid pump, when the discharge amount (discharge pressure) of the front-stage pump unit and the rear-stage pump unit is simply set to be the same, air or the like is mixed in the fluid to be sucked. The influence on the discharge characteristics is not taken into consideration. Therefore, when air is mixed in, there is a possibility that desired discharge characteristics (discharge amount) cannot be ensured.

JP-A-9-203308 JP-A-6-167278 Microfilm of Japanese Utility Model Application No. 2-1077738 (Japanese Utility Model Application Publication No. 4-65974) JP 2007-127071 A

  The present invention has been made in view of the above circumstances, and the object of the present invention is to guarantee the expected pump performance even if air or the like is mixed into the sucked oil, and to achieve a desired high level. An object of the present invention is to provide an oil pump having a pump characteristic capable of obtaining a discharge pressure (discharge amount).

An oil pump according to the present invention faces an upstream pump unit and a downstream pump unit that are arranged adjacent to each other in a predetermined axial direction, and an upstream pump unit for sucking oil from outside and guiding it to the upstream pump unit. The suction port formed in this way, the communication port that communicates with the downstream pump unit to guide the oil discharged from the upstream pump unit, and the oil that is discharged from the downstream pump unit to the outside A discharge port formed so as to face the downstream pump unit as much as possible, a discharge port for discharging air-mixed oil mixed with air to the outside, and a housing for accommodating the upstream pump unit and the downstream pump unit, the housing, interposed with communication hole interposed between the upstream pump unit and the downstream pump unit Includes a timber, inlet port, provided on the intermediate member, the outlet is provided on a portion of the housing located opposite the suction port across the upstream pump unit in the axial direction, it is configured Yes.
According to this configuration, when the oil pump is applied to, for example, an engine (a state where the oil in the oil pan is sucked and pressurized and supplied), the oil (lubricating oil) is supplied to the upstream pump unit (upstream inner rotor). And the upstream outer rotor) are sucked into the pump chamber, and the sucked-in air-containing oil is discharged from the discharge port to the outside while being pressurized and returned to the oil pan. The oil is pressurized to a predetermined pressure (for example, 3.0 MPa), and is pumped from the upstream pump unit to the downstream pump unit (upstream inner rotor and upstream outer rotor) through the communication port, and then downstream. It is sucked into the pump chamber by the pump action of the pump unit, and further boosted to a predetermined pressure (for example, 6.0 MPa) to discharge. Is discharged from the mouth to the outside, it is pumped towards the various lubrication areas.
Here, since the discharge port for discharging the air-mixed oil is formed so as to face the first-stage upstream pump unit, the density (mass) of the air (bubbles) mixed in the oil is small, that is, The air can be easily collected inside the pump chamber by the action of centrifugal separation, and the mixed air can be discharged efficiently.
In particular, provided on the intermediate member which inlet has an intervening to communication hole between the upstream pump unit and the downstream pump unit, on the opposite side of the inlet outlet sides of the upstream pump unit in the axial direction Since it is provided in a part of the housing located, the oil sucked from the suction port is surely pressurized in the upstream pump unit and the mixed air is discharged from the discharge port, and the remaining pressurized oil is discharged. It can send out to a downstream pump unit through a communicating port, and can improve the pump performance as a whole.

The said structure WHEREIN: The structure set so that the theoretical discharge amount of an upstream pump unit may become larger than the theoretical discharge amount of a downstream pump unit is employable.
According to this configuration, since the theoretical discharge amount of the upstream pump unit facing the discharge port is larger than the theoretical discharge amount of the downstream pump unit, even if oil mixed in from the discharge port is discharged to the outside, the downstream pump unit The unit can discharge a desired amount of oil.

In the above configuration, when the theoretical discharge amount of the upstream pump unit is Qu, the theoretical discharge amount of the downstream pump unit is Qd, and the discharge amount discharged from the discharge port is Qe,
Qu = Qd + Qe
It is the composition which satisfies.
According to this configuration, the relationship between the theoretical discharge amount Qu of the upstream pump unit, the theoretical discharge amount Qd of the downstream pump unit, and the discharge amount Qe from the discharge port satisfies Qu = Qd + Qe, that is, from the discharge port. Since the theoretical discharge amount is set in anticipation of the return amount (discharge amount) to be returned to the oil pan, it is possible to supply (discharge) a desired discharge amount to the outside while achieving high pressure by two-stage boosting. .

In the above configuration, a configuration in which the discharge amount Qe discharged from the discharge port is set to 20% or more of the theoretical discharge amount Qu of the upstream pump unit can be adopted.
According to this configuration, air (bubbles) mixed in the oil in the suction stroke by the upstream pump unit can be discharged more efficiently.

In the above configuration, when the thickness in the axial direction of the upstream pump unit is Wu, and the thickness in the axial direction of the downstream pump unit is Wd,
Wu> Wd
A configuration that satisfies the above can be adopted.
According to this configuration, the upstream pump unit is configured by changing the thickness in the axial direction while making the basic specifications of the upstream inner rotor and the upstream outer rotor and the downstream inner rotor and the downstream outer rotor the same. Can be easily set so that the theoretical discharge amount Qu is greater than the theoretical discharge amount Qd of the downstream pump unit.

In the above configuration, the housing includes a housing body having a recess for accommodating the upstream pump unit and the downstream pump unit, the intermediate member have a communication hole interposed between the upstream pump unit and the downstream pump unit, look including a housing cover which is connected so as to close the opening of the housing body, the outlet is provided in the housing cover, it is possible to adopt a configuration.
According to this configuration, the desired pump characteristics can be ensured while achieving a reduction in the outer diameter of the device, and the upstream pump unit, the interposed member, and the downstream pump unit can be secured to the housing body. The entire assembling work can be easily performed simply by housing the housing and attaching the housing cover thereon.

In the above configuration, the upstream pump unit and the downstream pump unit can each employ a configuration including four lobes and five nodes including a trochoid inner rotor and an outer rotor.
According to this configuration, the mixed air can be efficiently discharged, a desired high discharge amount can be secured, and the pump performance and durability can be improved.

  According to the oil pump having the above-described configuration, the pump performance can be ensured even if air or the like is mixed into the sucked oil, and the pump characteristic that a desired high discharge pressure (discharge amount) can be obtained is provided. An oil pump can be obtained.

It is a schematic diagram of the oil pump which concerns on this invention. It is a front view showing one embodiment of an oil pump concerning the present invention. It is sectional drawing which shows the inside of the oil pump shown in FIG. It is a front view which shows the housing main body which makes a part of oil pump shown in FIG. FIG. 3 shows a housing cover that forms part of the oil pump shown in FIG. 2, (a) is a plan view seen from the rear R side (inner surface side), and (b) is a cross-section at E1-E1 in (a). FIG. It is sectional drawing which shows the rotor case which makes a part of oil pump shown in FIG. FIG. 7 is an end view of the rotor case shown in FIG. 6, (a) is an end view seen from the front F side, and (b) is an end view seen from the rear R side. FIG. 3 shows a side plate that forms part of the oil pump shown in FIG. 2, (a) is a plan view seen from the front F side, and (b) is a cross-sectional view taken along E2-E2 in (a). It is sectional drawing which shows a part of oil pump shown in FIG. 2, (a) is the top view which looked at the upstream pump unit (1st inner rotor and 1st outer rotor) from the back R side, (b) is downstream It is the top view which looked at the side pump unit (a 2nd inner rotor and a 2nd outer rotor) from the front F side.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, the oil pump according to this embodiment includes a housing main body 10 and a housing cover 20 that form a housing H, a rotary shaft 30 that is rotatably supported around an axis S by the housing H, a housing H The rotor case 40 incorporated in the rotor, the side plate 50 that contacts the end surface of the rotor case 40, the O-ring 60 that biases the side plate 50 toward the rotor case 40 in the direction of the axis S, and the rotor case 40. An upstream pump unit 70 (first inner rotor 71 and first outer rotor 72), a downstream pump unit 80 (second inner rotor) accommodated in the rotor case 40 adjacent to the upstream pump unit 70 in the direction of the axis S. A rotor 81 and a second outer rotor 82).
The rotor case 40 and the side plate 50 are formed separately from the housing H. However, the rotor case 40 and the side plate 50 constitute a part of the housing so as to accommodate the upstream pump unit 70 and the downstream pump unit 80. is there.

  The housing body 10 is formed so as to form a recess that can accommodate the upstream pump unit 70 and the downstream pump unit 80 together with the rotor case 40 using an aluminum material for weight reduction or the like. As shown in FIG. 4, a bearing hole 11 that rotatably supports one end 31 of the rotary shaft 30 via a bearing G, a cylindrical inner peripheral surface 12 into which the rotor case 40 is fitted, and the inner peripheral surface 12 The two annular end surfaces 13 formed around the bearing hole 11 and a part of the inner peripheral surface 12 are formed by hollowing out and drilling radially outward. A suction passage 14 for sucking oil, a discharge passage 15 for discharging pressurized oil formed on the bottom side, a positioning hole 16 for positioning the side plate 50, a joint surface 17 for joining the housing cover 20, Screw holes 18 for screwing the bolts B for fastening the managing cover 20, and a positioning hole 19 and the like for positioning the housing cover 20.

  The housing cover 20 is made of the same aluminum material as that of the housing body 10 for weight reduction and the like, and the other end portion 32 of the rotary shaft 30 is interposed via a bearing G as shown in FIGS. The bearing hole 21 is rotatably supported, the concave portion 22 faces the suction port 44b described later in the direction of the axis S, the concave portion 23 faces the communication port 44e described later in the direction of the axis S, and is mixed in the sucked oil. A discharge port 24 for discharging air (aerated oil), a circular hole 25 through which the bolt B passes, a positioning hole 26 for positioning with the housing body 10, a positioning hole 27 for positioning the rotor case 40, and the like are provided.

The housing cover 20 is positioned so that the positioning pin fitted in the positioning hole 19 is fitted in the positioning hole 26 and the positioning hole 45a of the rotor case 40 so as to close the opening of the housing body 10. The pins are joined to the joining surface 17 so as to be fitted into the positioning holes 27, and the bolts B are passed from the outside through the circular holes 25 and screwed into the screw holes 18 so as to be connected to the housing body 10.
Here, as shown in FIGS. 5A and 9A, the discharge port 24 is formed so as to face the upstream pump unit 70, and extends in the radial direction passing through the axis S and has a diameter thereof. At the outer end in the direction, the upstream pump unit 70 (the first inner rotor 71 and the first outer rotor 72) is formed so as to open in a substantially L shape extending in the rotation direction (arrow direction).
Here, since the discharge port 24 for discharging the air-mixed oil is formed so as to face the upstream upstream pump unit 70, the density (mass) of the air (bubbles) mixed in the oil is small. That is, air can be easily collected inside the pump chamber by the action of centrifugal separation, and the mixed air can be efficiently discharged.
The discharge port is not limited to the discharge port 24 having the above-described form, and a desired form can be appropriately adopted according to the target discharge amount of the aerated oil.

  As shown in FIG. 3, the rotary shaft 30 is formed to extend in the direction of the axis S, using steel or the like, and is supported by the bearing hole 11 of the housing body 10 through the bearing G. , The other end portion 32 supported by the bearing hole 21 of the housing cover 20 through the bearing G, the shaft portion 33 for integrally rotating the first inner rotor 71 of the upstream pump unit 70, and the second pump portion 80 of the downstream pump unit 80. 2 A shaft portion 34 that integrally rotates the inner rotor 81, a shaft portion 35 that is supported by the bearing G, and the like are provided. The rotating shaft 30 is connected to a rotating member or the like that forms part of the engine and is driven to rotate.

  The rotor case 40 is formed using steel, cast iron, sintered steel, or the like. As shown in FIGS. 3, 6, and 7, the rotor case 40 has a cylindrical portion 41 centered on the axis S and inside the cylindrical portion 41. An inner peripheral surface 42 centered on an axis L1 deviated by a predetermined amount from the axis S, an inner peripheral surface 43 centered on an axis L2 deviated by a predetermined amount from the axis S inside the cylindrical portion 41, and an inner periphery in the direction of the axis S An intermediate wall 44 as an interposed member formed between the surface 42 and the inner peripheral surface 43, a bearing hole 44a provided in the intermediate wall 44, a suction port 44b provided in the intermediate wall 44, and an intermediate wall The upstream discharge port 44c (of the upstream pump unit 70) provided in 44, the downstream suction port 44d (of the downstream pump unit 80) provided in the intermediate wall 44, the upstream discharge port 44c and the downstream suction A communication port 4 through which the ports 44d communicate with each other e, the housing cover 20 is the end surface 45 abuts includes positioning holes 45a formed in the end face 45, the end face 46 side plate 50 abuts the positioning hole 46a or the like formed on the end face 46.

The cylindrical portion 41 can move relatively in the direction of the axis S according to the difference in thermal deformation (expansion and contraction) between the housing body 10 and the rotor case 40 while being in close contact with the inner peripheral surface 12 of the housing body 10. It is formed to have an outer diameter dimension that fits into the housing.
The inner peripheral surface 42 is formed to have a dimension that allows the first outer rotor 72 of the upstream pump unit 70 to be inscribed so as to be rotatable (slidable) about the axis L1.
The inner peripheral surface 43 is formed to have a dimension that allows the second outer rotor 82 of the downstream pump unit 80 to be inscribed so as to be rotatable (slidable) about the axis L2.
The suction port 44b communicates with the suction passage 14 and is formed so as to face the upstream pump unit 70 (the pump chamber P thereof).
Thus, the suction port 44b is provided in the intermediate wall 44 so as to be located on the opposite side of the discharge port 24 across the upstream pump unit 70 in the axis S direction (in other words, the discharge port 24 is The oil is sucked from the suction port 44b in the upstream pump unit 70 because it is provided on the opposite side of the intermediate wall 44, that is, the downstream pump unit 80 across the upstream pump unit 70 in the axis S direction. Thus, the pressure can be positively pressurized and sent to the downstream pump unit 80 through the communication port 44e, so that the pump performance as a whole can be improved.
The communication port 44e is formed so that the upstream discharge port 44c and the downstream suction port 44d communicate with each other, and the oil discharged from the upstream pump unit 70 is guided to the downstream pump unit 80.
The rotor case 40 cooperates with the end surface 13 in the state where the upstream pump unit 70 is accommodated on the inner peripheral surface 42 and the downstream pump unit 80 is accommodated on the inner peripheral surface 43 together with the rotary shaft 30. A positioning pin fitted in the positioning hole 16 is fitted into the positioning hole 46a while sandwiching the side plate 50, and is assembled (fitted) to the inner peripheral surface 12 of the housing body 10.

The side plate 50 is formed in a disc shape using steel, cast iron, sintered steel, aluminum alloy or the like, and as shown in FIGS. 3 and 8, a circular hole 51 through which the rotary shaft 30 passes, a downstream pump A discharge port 52 for discharging the oil pressurized by the unit 80, a positioning hole 53, a recess 54 for receiving one end side of the bearing G, and the like are provided.
Then, the side plate 50 is assembled to the housing body 10 such that the positioning pin fitted in the positioning hole 16 of the housing body 10 passes through the positioning hole 53 and the O-ring 60 is sandwiched between the side plate 50 and the end surface 13. It has become.

  The O-ring 60 is formed in an annular shape by an elastically deformable rubber material or the like, and is disposed between the end surface 13 of the housing body 10 and the side plate 50 so that the side plate 50 faces the end surface 46 of the rotor case 40. In order to energize, it is compressed and assembled by a predetermined compression amount in the direction of the axis S.

The upstream pump unit 70 is formed by using steel, sintered steel, or the like, and is composed of a first inner rotor 71 and a first outer rotor 72 as shown in FIG. 9A. It constitutes a trochoid pump with 5 leaves.
The first inner rotor 71 is formed as an external gear having a fitting hole 71a for fitting the shaft portion 33 of the rotating shaft 30 and having four peaks and valleys (dents) on the outer periphery thereof.
The first outer rotor 72 has an outer peripheral surface 72 a that is slidably fitted to the inner peripheral surface 42 of the rotor case 40, and four crests (external teeth) and troughs of the first inner rotor 71 on the inner periphery thereof ( It is formed as an internal gear having five ridges (inner teeth) and valleys (dents) that mesh with the dents.

  When the first inner rotor 71 rotates together with the rotary shaft 30 in the direction of the arrow (counterclockwise in FIG. 9A) about the axis S, the first outer rotor 72 interlocks to move the axis L1. By rotating in the direction of the arrow (counterclockwise in FIG. 9A) as the center, the volume of the pump chamber P defined by both changes, and oil is sucked from the suction port 44b and subsequently pressurized. In the pressurization process, the aerated oil is discharged from the discharge port 24, and then the remaining oil is discharged from the upstream discharge port 44c toward the downstream pump unit 80, and this process is continuously repeated. ing.

The downstream pump unit 80 is formed by using steel, sintered steel, or the like, and is composed of a second inner rotor 81 and a second outer rotor 82 as shown in FIG. 9B. It constitutes a trochoid pump with 5 leaves.
The second inner rotor 81 is formed as an external gear having a fitting hole 81a for fitting the shaft portion 34 of the rotating shaft 30 and having four peaks and valleys (dents) on the outer periphery.
The second outer rotor 82 has an outer peripheral surface 82a that is slidably fitted to the inner peripheral surface 43 of the rotor case 40, and has four crests (external teeth) and troughs (dents) of the second inner rotor 81 on the inner periphery. ) Is formed as an internal gear having five peaks (inner teeth) and valleys (dents).

  When the second inner rotor 81 rotates together with the rotating shaft 30 in the direction of the arrow (clockwise in FIG. 9B) about the axis S, the second outer rotor 82 is interlocked to center the axis L2. As shown in FIG. 9B, the volume of the pump chamber P defined by the both changes, and the oil is sucked from the downstream suction port 44d and subsequently pressurized. Subsequently, the oil is discharged from the discharge port 52 toward the external lubrication region, and this process is continuously repeated.

In the above configuration, the theoretical discharge amount (suction amount) of the upstream side pump unit 70 is Qu, the theoretical discharge amount (suction amount) of the downstream side pump unit 80 is Qd, and the discharge (of aeration oil) is discharged from the discharge port 24. When the amount is Qe,
Qu = Qd + Qe
It is formed to satisfy.
Thus, since the theoretical discharge amounts Qu and Qd are set in anticipation of the return amount (discharge amount Qe) returned from the discharge port 24 to the oil pan OP, the desired discharge amount is achieved while achieving high pressure by two-stage boosting. Qd can be supplied (discharged) toward the outside.
Here, the discharge amount Qe discharged from the discharge port 24 is preferably set in a range of 20% to 50% of the theoretical discharge amount Qu of the upstream pump unit 70.
Thereby, the air (bubbles) mixed in the oil in the suction stroke by the upstream pump unit 70 can be discharged more efficiently.

In the above configuration, as shown in FIG. 6, when the thickness in the axis S direction of the upstream pump unit 70 is Wu and the thickness in the axis S direction of the downstream pump unit 80 is Wd,
Wu> Wd
It is formed to satisfy.
In this way, by changing the thicknesses Wu and Wd in the direction of the axis S, while making the basic specifications of the upstream inner rotor 71 and the upstream outer rotor 72 and the downstream inner rotor 81 and the downstream outer rotor 82 the same, The theoretical discharge amount Qu of the upstream pump unit 70 can be easily set so as to be larger than the theoretical discharge amount Qd of the downstream pump unit 80.

  According to the oil pump having the above configuration, as shown in FIG. 1, when mounted on an engine equipped with an oil pan OP, the oil (lubricating oil) is first removed by the pump action of the upstream pump unit 70. The aspirated oil that has been sucked into the pump chamber P and subsequently sucked into the pump chamber P is discharged to the outside through the discharge port 24 while being pressurized, and then returned to the oil pan OP. , 3.0 MPa), pumped from the upstream pump unit 70 to the downstream pump unit 80 through the communication port 44e, and then sucked into the pump chamber P by the pumping action of the downstream pump unit 80. The pressure is increased to a predetermined pressure (for example, 6.0 MPa), discharged from the discharge port 52 to the outside, and pumped toward various lubrication regions. .

  When the oil pump having the above configuration is assembled, the housing H is constituted by the housing main body 10 and the housing cover 20, and the upstream pump unit 70 and the downstream pump unit 80 define an intermediate wall portion 44 as an interposed member. Since the configuration in which the rotor case 40 is separated and accommodated in advance is adopted, the upstream pump unit 70 and the downstream pump unit 80 are arranged in the rotor case 40 together with the rotating shaft 30, and the O-ring 60, side plate 50, the rotor case 40 can be accommodated in the housing body 10 in sequence, and then the housing cover 20 can be attached from above, so that the assembling work can be performed easily.

Next, the operation of the oil pump will be described with reference to FIGS. 9 (a) and 9 (b).
First, when the rotary shaft 30 is driven to rotate by the engine, the upstream pump unit 70 (the first inner rotor 71 and the first outer rotor 72) rotates counterclockwise in FIG. Is sucked into the pump chamber P of the upstream pump unit 70 through the suction passage 14 → the suction port 44b.
Then, the oil sucked into the pump chamber P is pressurized by the continuous rotation of the upstream pump unit 70, and in this pressurization process, the aerated oil is positively discharged from the discharge port 24 as a predetermined discharge amount Qe. The remaining amount of oil discharged outside and further subtracting the discharge amount Qe from the theoretical discharge amount Qu (Qu−Qe) passes through the upstream discharge port 44c → the communication port 44e → the downstream suction port 44d, and then the downstream side. The pressure is increased to a predetermined discharge pressure (about 3.0 MPa) and discharged (supplied) toward the pump unit 80.

Subsequently, the downstream pump unit 80 (the second inner rotor 81 and the second outer rotor 82) rotates clockwise in FIG. 9B, so that oil flows from the downstream suction port 44d to the downstream pump unit. It is sucked into 80 pump chambers P.
Then, the oil sucked into the pump chamber P is pressurized by the continuous rotation of the downstream pump unit 80, and passes through the discharge port 52 → the discharge passage 15 toward the external lubrication region to a predetermined discharge pressure ( The liquid is discharged (supplied) at a predetermined discharge amount (theoretical discharge amount Qd).

  Actually, the upstream pump unit 70 (first inner rotor 71 and first outer rotor 72) and the downstream pump unit 80 (second inner rotor 81 and second outer rotor 82) cooperate with each other in the first stage. Intake of oil from the oil pan OP in the first stage → Pressurization of oil in the first stage → Discharge of mixed air and oil in the first stage → Discharge of the remaining oil downstream in the first stage (second stage) Oil suction in the second stage) → pressurization of oil in the second stage → discharge of oil in the second stage is continuously performed.

  In this way, air (air bubbles) mixed in the oil is discharged together with the oil (as air-mixed oil) from the discharge port 24 facing the first-stage upstream pump unit 70. ) Is low in density (mass), and air can be easily collected inside the pump chamber by the action of centrifugal separation, and the mixed air can be discharged efficiently, and returned to the oil pan OP from the discharge port 24. Since the theoretical discharge amounts Qu and Qd in anticipation of the amount (discharge amount Qe) are set, it is possible to supply (discharge) the desired discharge amount Qd to the outside while achieving high pressure by two-stage boosting. it can.

In the above embodiment, the case where the present invention is adopted in the configuration including the rotor case 40 and the side plate 50 as the second housing inside the housing (the housing main body 10 and the housing cover 20) is shown. The present invention may be applied to a configuration in which the rotor case 40, the side plate 50, and the like are eliminated.
In the above embodiment, a two-stage trochoid pump including the upstream pump 70 (first inner rotor 71 and first outer rotor 72) and the downstream pump 80 (second inner rotor 81 and second outer rotor 82). However, the present invention is not limited to this, and the present invention is applied to a configuration including an inner gear (involute) type inner rotor and outer rotor. Also good.

In the above-described embodiment, the case where the present invention is adopted in the configuration in which the housing is separated into the housing main body and the housing cover is shown. However, the present invention is not limited to this. You may apply this invention in the structure provided with the housing which consists of a housing half body and a 2nd housing half body.
In the above-described embodiment, the case where the oil pump according to the present invention is applied to an engine mounted on an automobile or the like has been described. However, the present invention is not limited to this, for example, a continuously variable transmission (CVT) other than the engine. It can also be applied to.

  As described above, according to the oil pump of the present invention, the desired pump performance can be guaranteed even if air or the like is mixed into the sucked oil, and a desired high discharge pressure (discharge amount) can be obtained. Since pump characteristics can be achieved, it can be applied to engines mounted on automobiles, etc., as well as motorcycles, vehicles equipped with other engines, or continuously variable transmissions (CVT) that require pumping of lubricating oil. It is also useful for other mechanisms.

H Housing 10 Housing body (housing)
11 Bearing hole 12 Inner peripheral surface 13 End surface 14 Suction passage 15 Discharge passage 16 Positioning hole 17 Joint surface 18 Screw hole 19 Positioning hole 20 Housing cover (housing)
21 bearing hole 22 recessed portion 23 recessed portion 24 discharge port Qe discharge amount 25 discharged from discharge port 25 circular holes 26, 27 positioning hole 30 rotation axis S axis 31 one end portion 32 other end portions 33, 34, 35 shaft portion 40 rotor case 41 Cylindrical portion 42 Inner peripheral surface 43 Inner peripheral surface 44 Intermediate wall (intervening member)
44a Bearing hole 44b Suction port 44c Upstream discharge port 44d Downstream suction port 44e Communication port 45, 46 End face 45a, 45a Positioning hole 50 Side plate 51 Circular hole 52 Discharge port 53 Positioning hole 54 Recess 60 O-ring 70 Upstream pump unit Qu Theoretical discharge amount Wu of the upstream pump unit Th The thickness P in the axial direction of the upstream pump unit Pump chamber 71 First inner rotor 71a Fitting hole 72 First outer rotor L1 Axis 72a Outer peripheral surface 80 Downstream pump unit Qd Downstream side The theoretical discharge amount Wd of the pump unit Thickness 81 in the axial direction of the downstream pump unit 81 Second inner rotor 81a Fitting hole 82 Second outer rotor L2 Axis 82a Outer peripheral surface

Claims (7)

An upstream pump unit and a downstream pump unit that are arranged adjacent to each other in a predetermined axial direction so as to increase pressure in two stages;
A suction port formed so as to face the upstream pump unit so as to suck oil from the outside and guide it to the upstream pump unit, and boosts and discharges oil discharged from the upstream pump unit to the downstream pump unit. A communication port communicating to guide, a discharge port formed so as to face the downstream pump unit to discharge oil discharged from the downstream pump unit to the outside, and air-mixed oil mixed with air A housing having a discharge port for discharging to the outside, and housing the upstream pump unit and the downstream pump unit,
The housing includes an interposition member having the communication hole interposed between the upstream pump unit and the downstream pump unit,
The suction port is provided in the interposed member,
The discharge port is provided in a part of the housing located on the opposite side of the suction port across the upstream pump unit in the axial direction.
An oil pump characterized by that. The theoretical discharge amount of the upstream pump unit is set to be larger than the theoretical discharge amount of the downstream pump unit,
The oil pump according to claim 1 . When the theoretical discharge amount of the upstream pump unit is Qu, the theoretical discharge amount of the downstream pump unit is Qd, and the discharge amount discharged from the discharge port is Qe,
Qu = Qd + Qe
Satisfy,
The oil pump according to claim 1 or 2 , characterized in that. The discharge amount Qe discharged from the discharge port is set to 20% or more of the theoretical discharge amount Qu of the upstream pump unit.
The oil pump according to claim 3 . When the thickness in the axial direction of the upstream pump unit is Wu, and the thickness in the axial direction of the downstream pump unit is Wd,
Wu> Wd
Satisfy,
The oil pump according to any one of claims 1 to 4, wherein: The housing includes a housing body having a recess for accommodating the upstream pump unit and the downstream pump unit, the interposition member, and a housing cover connected to close an opening of the housing body,
The discharge port is provided in the housing cover,
The oil pump according to claim 1 . The upstream pump unit and the downstream pump unit each have four leaves and five nodes including a trochoid inner rotor and an outer rotor.
The oil pump according to any one of claims 1 to 6 , wherein the oil pump is provided.

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