CN107795479B

CN107795479B - Oil pump

Info

Publication number: CN107795479B
Application number: CN201710756179.7A
Authority: CN
Inventors: 今井太一; 早川幸弘; 千本木雄二; 柏惠介
Original assignee: Yamada Manufacturing Co Ltd
Current assignee: Yamada Manufacturing Co Ltd
Priority date: 2016-08-31
Filing date: 2017-08-29
Publication date: 2023-03-31
Anticipated expiration: 2037-08-29
Also published as: CN107795479A

Abstract

The pump is provided with a pump housing (D), a drive shaft (A) provided with a first external fitting tooth profile part (A1) and a second external fitting tooth profile part (A2), a first rotor (B) which is provided with a first internal fitting tooth profile part (B1) and is accommodated in a first rotor chamber (51), and a second rotor (C) which is provided with a second internal fitting tooth profile part (C1) which is equal to the first internal fitting tooth profile part (B1) and is accommodated in a second rotor chamber (61). The first rotor (B) and the second rotor (C) can be mounted on the drive shaft (A) only when the groove filling section (22) and the tooth missing section (42) are respectively matched, the phases of the external teeth (3) of the first rotor and the second rotor are matched, and the set of the first suction port (53) and the first discharge port (54) of the first rotor chamber (51) and the set of the second suction port (63) and the second discharge port (64) of the second rotor chamber (61) are the same and the phases are offset from each other.

Description

Oil pump

Technical Field

The present invention relates to an oil pump having excellent strength and rigidity, which can easily and efficiently assemble a rotor and a drive shaft to be incorporated into a multi-row pump including a plurality of rotors for feeding oil to an engine, a transmission, and the like of an automobile in an axial direction, or a pump in which these pumps are connected in parallel or in series.

Background

Various oil pumps have been developed which are of a multi-row type including a plurality of rotors of an internal connection type, an external connection type, or the like in an axial direction and which connect pumps in parallel or in series with each other. In this oil pump, two or more rows of rotors are mounted on one drive shaft. The rotor is a rotor of internal connection or external connection gear type or a rotor of vane pump type.

As an example thereof, there is patent document 1 (japanese patent laid-open No. 2006-132342). Patent document 1 discloses a double feed pump and a quadruple purge pump (scavenging pump). In patent document 1, a plurality of internal gear type rotors are attached to a serration (gearing) portion of one drive shaft. In particular, although inner rotors of an internal gear type rotor are mounted at the serration parts, the number of teeth of these inner rotors is the same.

In general, when a plurality of internal gear type rotors attached to a drive shaft in an axial direction are rotated by the rotation of the drive shaft, the phases of the inner rotors in a circumferential direction are shifted to suppress pulsation or vibration of the pump. Although the amount of phase shift is determined according to the number of teeth of the inner rotor, specifically, the formation position of the teeth of one inner rotor is not matched with the formation position of the teeth of the other inner rotor, and a configuration in which the adjacent teeth are shifted by half a tooth from the middle of the teeth is often employed.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open No. 2006-132342.

Disclosure of Invention

Problems to be solved by the invention

As described above, there is a structure in which the phase of the inner rotor in the circumferential direction is shifted in order to suppress pulsation or vibration of the pump. However, in the case where the phases of the plurality of inner rotors to be mounted are set to be offset so as not to coincide with the drive shaft, the plurality of inner rotors must be correctly mounted with respect to the drive shaft. Also, the serration of the drive shaft is constituted by a plurality of teeth as seen from patent document 1. Similarly, in the shaft hole of the inner rotor, a plurality of teeth having the same number as the teeth of the serration are formed so as to be capable of meshing with the serration formed by the plurality of teeth.

However, if the number of teeth of the serration of each of the drive shaft and the inner rotor shaft hole is large as described above, the serration (or spline) and the shaft hole of the inner rotor having the same number of teeth as the serration (or spline) cause the following problem in the assembly work of the drive shaft and the inner rotor. First, it is possible to easily assemble the other inner rotor adjacent in the axial direction to the drive shaft at a level close to a target appropriate phase with respect to the mounted state of the one inner rotor to the drive shaft.

However, it is extremely difficult to perform the work of attaching the two inner rotors to the drive shaft so that the phases of the two inner rotors match each other extremely accurately. For example, even if the saw-tooth portion is shifted by one tooth, the oil pump may not exhibit the intended performance. That is, as described above, there are extremely many teeth in the serration part, and there is a problem that the work for attaching the two inner rotors to the drive shaft in the target phase is extremely complicated, and the work efficiency is lowered. That is, patent document 1 suggests that it is extremely difficult to achieve an accurate configuration in mounting a plurality of inner rotors on one drive shaft.

An object of the present invention (a technical problem to be solved) is to improve work efficiency by facilitating accurate mounting of a plurality of inner rotors of a plurality of internal connection gear rotors attached to a drive shaft and by mounting the inner rotors in a very small number of steps in a multi-row type oil pump having a plurality of rotors in an axial direction and connecting pumps in parallel or in series.

Means for solving the problems

Therefore, in order to solve the above problem, the inventors have made extensive and intensive studies and as a result, the invention according to claim 1 is an oil pump including: a pump housing having a first rotor chamber and a second rotor chamber; a drive shaft provided with a first external fitting tooth-shaped portion in which a groove filling portion is provided in a fitting groove arranged in a circumferential direction at a predetermined interval from the fitting groove, and a second external fitting tooth-shaped portion having a configuration equivalent to that of the first external fitting tooth-shaped portion; a first rotor having a first inner spline tooth-shaped portion provided with a tooth-lacking portion combined with the groove-filling portion and an outer tooth, and accommodated in the first rotor chamber; and a second rotor that has a second internal spline tooth profile portion equivalent to the first internal spline tooth profile portion and an equivalent number of external teeth, and that is housed in the second rotor chamber, wherein the first rotor and the second rotor are mounted on the drive shaft only when the filling groove portion and the missing tooth portion respectively coincide, and the external teeth of the first rotor and the second rotor have a phase that coincides, and a group of a first suction port and a first discharge port of the first rotor chamber and a group of a second suction port and a second discharge port of the second rotor chamber have the same configuration and are offset in phase from each other.

The invention according to claim 2 solves the above-described problem by providing the oil pump according to claim 1, wherein a first large-to-medium separation portion between a terminal end of the first suction port and a start end of the first discharge port and a second large-to-medium separation portion between a terminal end of the second suction port and a start end of the second discharge port are configured so that phases thereof are shifted from each other. The invention according to claim 3 solves the above-described problem by providing the oil pump according to claim 1 or 2, wherein the amount of the phase difference between the set of the first suction port and the first discharge port and the set of the second suction port and the second discharge port is set to the half tooth amount of the external teeth of the rotor.

The invention according to claim 4 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, and 3, wherein the groove filling portion is provided at an axial direction tip end of the fitting groove. The invention according to claim 5 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, and 3, wherein the groove filling portion is provided at an axially inner end of the fitting groove.

The invention according to claim 6 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, and 3, wherein the filling groove portion is provided over the entire fitting groove in the axial direction. The invention according to claim 7 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, 3, 4, 5, and 6, wherein the filling groove portion has a height from a bottom surface of the fitting groove to a substantially middle portion in a tooth dimension direction.

The invention according to claim 8 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, 3, 4, 5, and 6, wherein the filling groove portion is formed to have a height from a bottom surface of the fitting groove to a top portion in a tooth dimension direction. The invention according to claim 9 solves the above-described problem by providing the oil pump according to any one of

claims

1, 2, 3, 4, 5, 6, 7, or 8, wherein the first external fitting tooth profile portion and the second external fitting tooth profile portion are integrally and continuously formed in the drive shaft in the axial direction.

Effects of the invention

In the invention according to claim 1, the first rotor and the second rotor are attached at proper phases only when the respective caulking grooves of the first externally fitted tooth profile and the second externally fitted tooth profile of the drive shaft are fitted to the respective missing teeth of the first rotor and the second rotor. Therefore, the first rotor and the second rotor, which are appropriately attached to the first external fitting tooth profile and the second external fitting tooth profile of the drive shaft, respectively, can match the phases of the external teeth. Further, by adopting a configuration in which the group of the first suction port and the first discharge port of the first rotor chamber and the group of the second suction port and the second discharge port of the second rotor chamber are of the same configuration and are shifted in phase from each other, the timings of the discharge of the first rotor and the discharge of the second rotor can be shifted, and pulsation can be suppressed.

In the present invention, the portion having the positioning function is configured by the caulking groove portion provided in the fitting groove arbitrarily selected from the plurality of fitting grooves formed in the first outer fitting tooth-shaped portion and the second outer fitting tooth-shaped portion of the drive shaft. Further, an inner spline tooth selected arbitrarily from a plurality of inner spline teeth of each of the first inner spline tooth section of the first rotor and the second inner spline tooth section of the second rotor is cut out as a missing tooth section, and the missing tooth section is combined with the filling groove section.

Further, when the first inner engaging tooth profile of the first rotor is attached to the first outer engaging tooth profile of the drive shaft and when the second inner engaging tooth profile of the second rotor is attached to the second outer engaging tooth profile of the drive shaft, the filling groove portion abuts against the tip end of the inner engaging tooth except when the filling groove portion and the missing tooth portion are aligned, so that complete insertion of the first rotor and the second rotor is impossible, and an insertion error at an inappropriate position can be found, whereby the work efficiency can be improved.

In the invention according to claim 2, the phase of the first large-to-medium partition between the terminal end of the first suction port and the start end of the first discharge port and the phase of the second large-to-medium partition between the terminal end of the second suction port and the start end of the second discharge port are shifted from each other, whereby the effect equivalent to that of claim 1 can be achieved, the shift of the discharge timing can be more reliably achieved, and the quieter pump operation in which pulsation is suppressed can be achieved.

In the invention according to claim 3, the difference between the phases of the group of the first intake port and the first discharge port and the group of the second intake port and the second discharge port is set to the half-tooth amount of the external teeth of the rotor, so that the structure for suppressing pulsation and vibration during operation of the multi-row type oil pump can be made extremely simple on an extremely simple basis.

In the invention according to claim 4, since the caulking groove portion is provided at the axial direction leading end of the fitting groove, when the first inner fitted tooth profile portion of the first rotor is attached to the first outer fitted tooth profile portion of the drive shaft and when the second inner fitted tooth profile portion of the second rotor is attached to the second outer fitted tooth profile portion of the drive shaft, the caulking groove portion and the leading end of the inner fitted tooth come into contact with each other except when the positions of the caulking groove portion and the missing tooth portion are matched, and insertion from the initial stage of insertion of the first rotor and the second rotor is not possible, and an insertion error at an inappropriate position can be found at the initial stage, and work efficiency can be improved. In the invention of claim 5, since the caulking portions are provided at the axial inner ends of the fitting grooves, the first rotor and the second rotor cannot be completely inserted, and an insertion error at an inappropriate position can be found, whereby the work efficiency can be improved.

In the invention of claim 6, the filling groove portion is provided integrally in the axial direction of the fitting groove, and therefore, when the first external fitting tooth-shaped portion and the second external fitting tooth-shaped portion are molded in the manufacturing of the drive shaft, the leading end and the inner end of the filling groove portion are formed integrally with the fitting groove by the molding machine, and therefore, the manufacturing efficiency is improved and the drive shaft can be provided at a low cost.

In the invention according to claim 7, the fitting force of the first outer fitting tooth profile portion and the first inner fitting tooth profile portion and the second outer fitting tooth profile portion and the second inner fitting tooth profile portion can be further improved by setting the fitting groove portion to a height from the bottom surface of the fitting groove to a substantially middle portion in the tooth dimension direction so that a small amount of the inner fitting teeth can be left even in the tooth-missing portion. In the invention according to claim 8, the oil pump is provided as the filling groove portion having a height from the bottom surface of the fitting groove to the top portion in the tooth dimension direction, whereby the first outer fitting tooth profile portion and the first inner fitting tooth profile portion, and the second outer fitting tooth profile portion and the second inner fitting tooth profile portion can be formed in a simpler shape.

In the invention of claim 9, by adopting a configuration in which the first external fitting tooth shape portion and the second external fitting tooth shape portion in the drive shaft are integrally and continuously formed in the axial direction, and making the first external fitting tooth shape portion and the second external fitting tooth shape portion a spline-shaped shaft which is continuous in the axial direction, the shape and configuration of the drive shaft can be simplified. Therefore, the first external fitting tooth shape portion and the second external fitting tooth shape portion can be manufactured by one manufacturing process, instead of separately forming the first external fitting tooth shape portion and the second external fitting tooth shape portion, and the driving shaft can be provided at a low cost with good manufacturing efficiency.

Drawings

In FIG. 1, (A) is a longitudinal sectional side view of the oil pump of the present invention, (B) is a sectional view of (A) taken along Y1-Y1, and (C) is a sectional view of (A) taken along Y2-Y2;

in fig. 2, (a) is a longitudinal sectional side view of an assembled state of the drive shaft and the first and second rotors in the present invention, (B) is a cross-sectional view taken along Y3-Y3 of (a), and (C) is an enlarged view of a portion (α) of (B);

in fig. 3, (a) is a perspective view of a state in which a first external fitting tooth portion of the drive shaft and the first rotor are separated, (B) is an enlarged view of a portion (β) of (a), (C) is an enlarged cross-sectional view of a main portion showing an embodiment of the groove filling portion and the tooth missing portion, (D) is an enlarged cross-sectional view of a main portion showing another embodiment of the groove filling portion and the tooth missing portion, and (E) is an enlarged view of a main portion of an embodiment in which the groove filling portion is formed on an axial inner end side of the fitting groove;

in fig. 4, (a) is a sectional view of the first outer fitting tooth profile of the drive shaft orthogonal to the axial direction, (B) is a developed view of Y4-Y4 of (a), (C) is a sectional view of the first inner fitting tooth profile of the first rotor orthogonal to the axial direction, (D) is a developed view of Y5-Y5 of (C), (E) is a schematic end view showing a state where the first outer fitting tooth profile and the first inner fitting tooth profile are fitted and mounted appropriately, and (F) is an end view showing a state where the first outer fitting tooth profile and the first inner fitting tooth profile are not fitted and mounted appropriately;

in FIG. 5, (A) is a longitudinal sectional side view of the pump housing in an exploded manner, (B) is a Y6-Y6 direction view of (A), (C) is a Y7-Y7 direction sectional view of (A);

in fig. 6, (a) is a schematic view of a state in which the first inner rotor and the first outer rotor are discharging, (B) is a schematic view of a state in which the second inner rotor and the second outer rotor are discharging;

in fig. 7, (a) is a main portion enlarged perspective view of the first outer fitting tooth profile of the drive shaft in the second embodiment, (B) is a cross-sectional view of the first outer fitting tooth profile of the drive shaft in the second embodiment, which is orthogonal to the axial direction, (C) is a developed view of Y5-Y5 of (B), and (D) is a schematic end view showing a state where the first outer fitting tooth profile and the first inner fitting tooth profile are fitted and mounted appropriately;

fig. 8 shows a vertical sectional side view of a state in which the first rotor and the second rotor are assembled to the drive shaft according to the other embodiment, and (B) shows a vertical sectional side view of a state in which the drive shaft is to be attached to the second rotor, the spacer, and the first rotor in this order.

Detailed Description

Embodiments of the present invention are described below with reference to the drawings. The present invention relates to a drive shaft and a plurality of rotors in an oil pump having a plurality of rotors of an internal or external type or rotors used in a vane pump in an axial direction. As shown in fig. 1, the present invention is mainly composed of a drive shaft a, a first rotor B, a second rotor C, and a pump housing D.

As shown in fig. 1 (a), the first rotor B is accommodated in a first rotor chamber 51 of the pump housing D, and the second rotor C is accommodated in a second rotor chamber 61 of the pump housing D in a state where the first rotor B and the second rotor C are attached to the drive shaft a, thereby constituting an oil pump. The first rotor B constitutes a main pump together with the first rotor chamber 51, and the second rotor C constitutes a sub pump together with the second rotor chamber 61.

The drive shaft a performs a function of supporting the first rotor B and the second rotor C in the axial direction, which will be described later. As shown in fig. 2 (a), the drive shaft a includes a first shaft portion 1a, a second shaft portion 1b, and an intermediate shaft portion 1 c. The first shaft portion 1a and the second shaft portion 1b are located at both ends of the drive shaft a in the axial direction. In the drive shaft a, the shaft diameter of the intermediate shaft portion 1c is the largest, and the first shaft portion 1a and the second shaft portion 1b are formed to have smaller outer diameters than the intermediate shaft portion 1 c. A first external fitting tooth profile A1 is formed at a boundary portion between the first shaft portion 1a and the intermediate shaft portion 1c, and a second external fitting tooth profile A2 is formed at a boundary portion between the second shaft portion 1b and the intermediate shaft portion 1 c.

The first external fitting tooth profile A1 is a portion formed by a plurality of fitting grooves 21,. That extend in the axial direction on the outer periphery of a substantially cylindrical shaft-shaped fitting shaft 2, and are arranged at equal intervals in the circumferential direction (see fig. 2 (B) and (C)). In the arrangement of the plurality of fitting grooves 21, the caulking portion 22 is formed in any one of the fitting grooves 21 selected at a predetermined interval (see fig. 3).

A plurality of selected arbitrary fitting grooves 21 of the fitting shaft portion 2 are present, and these arbitrary fitting grooves 21 are arranged at equal intervals along the outer periphery of the fitting shaft portion 2. The filling groove portion 22 is provided in any selected fitting groove 21 (see fig. 2 (B), (C), and fig. 3). Further, the fitting grooves 21 of the first external fitting tooth profile A1 and the second external fitting tooth profile A2 of the drive shaft a include portions referred to as a distal end side and an inner end side. The front end side refers to a portion located on a side close to both ends (shaft ends) in the axial direction of the drive shaft a. The inner end of the fitting groove 21 is a portion located on a side close to the center of the drive shaft a in the axial direction (see fig. 2 a).

Further, the first outer fit tooth profile A1 and the second outer fit tooth profile A2, which are constituted by the aforementioned fitting groove 21 and the filling groove portion 22 provided in the fitting groove 21, are attached in an optimum state, so that the first outer fit tooth profile A1 and the first rotor B, and the second outer fit tooth profile A2 and the second rotor C are each attached, and the filling groove portion 22 is a portion that functions as a positioning portion for preventing erroneous attachment. Further, there are various embodiments for the filling groove portion 22. First, the first embodiment of the filling groove portion 22 is a wall-shaped portion formed from a position at the tip end in the axial direction of the arbitrarily selected fitting groove 21 toward the middle portion in the axial direction and orthogonal to the axial direction of the fitting groove 21 (see fig. 2C, 3a, 3B, and 4).

The first embodiment of the caulking portion 22 is formed in a predetermined range on the distal end side in the axial direction of any of the fitting grooves 21. Specifically, the fitting groove 21 may be formed in a predetermined range near the axial distal end position. Fig. 4 (a) and (B) are views showing a portion of the first external fitting tooth profile portion A1 where the caulking portion 22 is formed and its developed view, and show that the caulking portion 22 is formed on the axial direction front end side of the fitting groove 21.

The groove filling portion 22 is sometimes provided at an axially intermediate portion of the fitting groove 21, although not shown. In this case, the caulking portion 22 is also preferably provided at a position near the axial direction front end of the fitting groove 21. The caulking portion 22 is formed integrally with the fitting groove 21, or is formed of a separate member from the drive shaft a and is fixed by welding or the like. In the first embodiment of the filling groove portion 22, it may be formed within a predetermined range on the inner end side in the axial direction of any of the fitting grooves 21 (see fig. 3E).

Next, in the second embodiment of the groove filling portion 22, the groove filling portion 22 is provided over the entire axial direction of any of the fitting grooves 21. Any fitting groove 21 in the second embodiment of the filling groove portion 22 is equivalent to any selected fitting groove 21 in the first embodiment of the filling groove portion 22 (see fig. 7 (a), (B), and (C)). The caulking portion 22 serves to properly attach the first rotor B and the second rotor C to the drive shaft a and prevent erroneous attachment, as described above.

Therefore, the caulking portions 22 may be large enough to be able to abut against the inner engaging teeth 41 of the first rotor B and the second rotor C into which the fitting grooves 21 of the caulking portions 22 are to be inserted. Specifically, the filling groove portion 22 may have an arbitrary height in the tooth dimension direction from the bottom surface of the fitting groove 21, specifically, a height up to a substantially middle portion of the fitting groove 21 (see fig. 3C), or a height up to the top portion in the tooth dimension direction from the bottom surface of the fitting groove 21 (see fig. 3D).

The tooth-shaped portion, which is formed by the adjacent

fitting grooves

21, 21 and the filling groove portion 22, selected from the row of the plurality of

fitting grooves

21, 21. The filling groove portion 22 is provided at a height from the bottom surface of the fitting groove 21 to a substantially middle portion in the tooth dimension direction (see fig. 3C), or at a height from the bottom surface of the fitting groove 21 to a top portion in the tooth dimension direction (see fig. 3D).

In the first external fitting tooth profile A1, a plurality of fitting grooves 21, 21 a are formed at equal intervals in the circumferential direction on the outer periphery of the substantially cylindrical fitting shaft portion 2 so as to extend in the axial direction. In the plurality of fitting grooves 21,. The adjacent

fitting grooves

21, 21 are formed with a tooth shape therebetween. The portion of the tooth profile is referred to as a tooth-shaped portion 23 (see fig. 3B). That is, the fitting grooves 21 and the tooth-shaped portions 23 form gear-shaped portions alternately arranged in the circumferential direction.

The total number of the fitting grooves 21 of the first and second external fitting tooth profiles A1 and A2 is preferably an integer multiple of the number of external teeth 3,. Of the first and second rotors B and C, respectively, which will be described later. The mounting side surface of the first rotor B is inserted and fitted toward the first outer fitting tooth profile A1 from the axially outer side of the first outer fitting tooth profile A1 of the drive shaft a. Similarly, the mounting side surface of the second rotor C is inserted into the second outer fitting tooth form portion A2 from the axially outer side of the second outer fitting tooth form portion A2 of the drive shaft a.

The first rotor B and the second rotor C are both gear type rotors used as an internal gear or an external gear, or rotors used in a vane pump. The first rotor B of the internal gear serves as an inner rotor, the pair of first outer rotors 81 are combined with the first rotor B, and the pair of second outer rotors 82 are also combined with the second rotor C of the internal gear to serve as an inner rotor, and are attached to the pump housing D together with the drive shaft a (see fig. 1 a).

Hereinafter, the first rotor B and the second rotor C will be described as gear-type rotors used as trochoidal pumps (trochoidal pumps). The first rotor B has a plurality of

external teeth

3, 3 formed on the outer periphery thereof, and a first inner spline tooth portion B1 formed at the center in the radial direction. The first rotor B is a rotor in which the external teeth 3 have a tooth shape substantially similar to a cycloid curve as an internal gear or a cycloid curve.

In the first internal fitting tooth profile part B1, the same number of internal fitting teeth 41 extending in the shaft-hole penetrating direction as the fitting grooves 21 of the first external fitting tooth profile part A1 are provided on the inner peripheral side surface of the fitting hole 4 formed at the center position of the diameter, and the internal fitting teeth 41 selected arbitrarily from among them are cut off, and the cut-off portion is referred to as a tooth-missing portion 42. The toothless portions 42 are formed in the same number and at equal intervals as the filling groove portions 22 of the first external spline tooth portion A1. The positional relationship between the internal fitting teeth 41 and the tooth-missing portions 42 is equivalent to the positional relationship between the fitting groove 21 in the first external fitting tooth-shaped portion A1 and the fitting groove 21 provided with the filling groove portion 22 (see fig. 4 (C) and (E)).

The serration 42 is a portion formed by cutting a part or all of the inner fitting tooth 41 as shown in fig. 3 (C) and (D). The tooth missing portion 42 may be formed so that a part of the inner fitting tooth 41 remains. In the case where the missing tooth portion 42 is configured such that a part of the inner engaging tooth 41 remains, the filling groove portion 22 corresponds to the filling groove portion 22 of the first outer engaging tooth portion A1 of the drive shaft a, which is set to a height from the bottom surface to the middle of the tooth size. In this case, the remaining inner engaging teeth 41 of the missing tooth portion 42 can be inserted into the fitting groove 21 without interfering with the filling groove portion 22.

In the embodiment, in the first rotor B, the number of teeth of the external teeth 3 is set to 6, and the number of inner fitting teeth 41,. Cndot.of the first inner fitting tooth profile part B1 is set to 18 (see fig. 2 (B) and (C)). Of the 18 inner engaging

teeth

41, 3 inner engaging teeth 41 are arbitrarily removed at equal intervals (at equal angles) to be the missing tooth portions 42. The passing position of the serration 42 coincides with the position of the groove filling portion 22 in the first external fitting tooth profile A1 of the drive shaft a, and the serration can be fitted in a state where the first external fitting tooth profile A1 and the first internal fitting tooth profile B1 are completely inserted without interfering with each other.

The second inner spline tooth portion C1 of the second rotor C has the same configuration as the first inner spline tooth portion B1 of the first rotor B, and has a structure substantially the same as and the same as the first rotor B except for the dimension in the thickness direction. The first inner engaging tooth-shaped portion B1 of the first rotor B is fitted to the first outer engaging tooth-shaped portion A1 (see fig. 2) of the drive shaft a, and the second inner engaging tooth-shaped portion C1 of the second rotor C is fitted to the second outer engaging tooth-shaped portion A2 of the drive shaft a.

The first rotor B is attached to the first outer engaging tooth profile A1 while the first outer engaging tooth profile A1 of the drive shaft a and the first inner engaging tooth profile B1 of the first rotor B are engaged with each other. At this time, the first external fitting tooth profile portion A1 and the first internal fitting tooth profile portion B1 are fitted so as to be inserted into the fitting groove 21 not provided with the groove filling portion 22, and only the tooth missing portion 42 is fitted into the fitting groove 21 provided with the groove filling portion 22. The tooth missing part 42 is completely inserted and fitted into the fitting groove 21 provided with the groove filling part 22, and in this state, the first inner fitting tooth profile B1 of the first rotor B is appropriately attached to the first outer fitting tooth profile A1 of the drive shaft a (see fig. 2C, 4E, and 7D).

Further, the inner engaging teeth 41 of the first inner engaging tooth profile portion B1 cannot be inserted and fitted into the fitting groove 21 of the first outer engaging tooth profile portion A1 in which the filling groove portion 22 is provided. In particular, in the first embodiment of the caulking portion 22, since the caulking portion 22 is provided at the axial direction front end of the fitting groove 21, when the inner fitting teeth 41 of the first inner fitting tooth profile portion B1 are to be inserted, the axial direction end portions of the inner fitting teeth 41 come into contact with the caulking portion 22, and the insertion is not possible from the initial stage (see fig. 4F). Thus, the erroneous mounting of the first rotor B or the second rotor C to the drive shaft a can be recognized at the initial stage, and the work efficiency can be improved.

As described above, the following configuration is adopted: the first rotor B cannot be attached to the first outer fitting tooth profile portion A1 of the drive shaft a unless all of the other fitting grooves 21,. Cndot.s of the first outer fitting tooth profile portion A1 where the caulking groove portions 22 are not provided, all of the inner fitting teeth 41,. Cndot.s of the first inner fitting tooth profile portion B1 are completely matched, and the positions (phases) of the caulking groove portions 22 and the missing tooth portions 42 are matched.

The external teeth 3,. Of the first rotor B and the external teeth 3,. Of the second rotor C, which are appropriately attached to the drive shaft a, have a configuration in which the phases are identical. The coincidence means that the outer teeth 3,. Of the first rotor B and the outer teeth 3,. Of the second rotor C are aligned with each other in a row in the axial direction. If the phases of the external teeth 3,. Of the first rotor B and the external teeth 3,. Of the second rotor C are identical, the phases of the first externally fitted tooth profile A1 and the second externally fitted tooth profile A2 in the drive shaft a may be identical or not identical.

The phase of the first external fitting tooth profile A1 and the phase of the second external fitting tooth profile A2 in the drive shaft a are not matched with each other, and the phase is set so that the position of the fitting portion 21 provided with the caulking groove portion 22 in the first external fitting tooth profile A1 and the position of the fitting portion 22 provided with the caulking groove portion 22 in the second external fitting tooth profile A2 are shifted from each other. When the number of the fitting grooves 21 of the first external fitting tooth profile A1 is set to 18 and the number of the caulking grooves 22 is set to 3, the caulking grooves 22 arranged at equal intervals in the first external fitting tooth profile A1 are provided at intervals of 120 °. The second external fitting tooth profile portion A2 is also configured similarly to the first external fitting tooth profile portion A1.

As described above, when the first inner spline tooth portion B1 of the first rotor B is fitted to the first outer spline tooth portion A1 of the drive shaft a, if the positions of the spline portion 22 of the first outer spline tooth portion A1 and the serration portion 42 of the first inner spline tooth portion B1 do not match, the first inner spline tooth portion B1 cannot be inserted into the first outer spline tooth portion A1. That is, when the first rotor B is appropriately attached to the first externally fitted tooth profile portion A1 of the drive shaft a, the phase (angle) of the external teeth 3,. Of the first rotor B can be set so as to be always the same phase (angle) with respect to the drive shaft a. The same applies to the drive shaft a and the second rotor C.

Next, the pump housing D will be explained. The pump housing D is mainly constituted by a first pump housing 5, a second pump housing 6, and a partition block 7. The first pump casing 5 has a first rotor chamber 51, and the second pump casing 6 has a second rotor chamber 61 (see fig. 1a and 5 a).

Further, the partition block 7 is placed in the middle, and the first pump casing 5 and the second pump casing 6 are disposed on both sides thereof and joined. Thereby, the first rotor chamber 51 and the second rotor chamber 61, which are closed spaces, are formed in the pump housing D. The spacer block 7 has a first joint surface 7a with the first pump casing 5 and a second joint surface 7b with the second pump casing 6 (see fig. 5 a).

The first rotor B is accommodated in the first rotor chamber 51, and the second rotor C is accommodated in the second rotor chamber 61 (see fig. 1 a). Shaft support holes 52, 62, and 72 for supporting the drive shaft a are formed in the first and

second pump casings

5 and 6 and the partition block 7, respectively.

A first suction port 53 and a first discharge port 54 are formed in the first rotor chamber 51 of the first pump housing 5 with the shaft support hole 52 as the center (see fig. 1B and 5B). In addition, a terminal end and a starting end are set at the first suction port 53 and the first discharge port 54, respectively, in the rotation direction of the first rotor B accommodated in the first rotor chamber 51.

The first suction port 53 has a starting end 53a and a terminating end 53b, and the first discharge port 54 has a starting end 54a and a terminating end 54b. Between a terminal end 53b of the first suction port 53 and a starting end 54a of the first discharge port 54, a first large intermediate partition 55 is formed. Further, a first small intermediate partition 56 is formed between the starting end 53a of the first suction port 53 and the terminal end 54b of the first discharge port 54.

Similarly, a second suction port 63 and a second discharge port 64 are formed in the second rotor chamber 61 of the second pump housing 6 with the shaft support hole 62 as the center (see fig. 1C and 5C). Further, a terminal end and a start end are set in the second suction port 63 and the second discharge port 64, respectively, in the rotational direction of the second rotor C accommodated in the second rotor chamber 61.

The second suction port 63 has a starting end 63a and a terminating end 63b, and the second discharge port 64 has a starting end 64a and a terminating end 64b. Further, a second large intermediate partition 65 is formed between the terminal end 63b of the second suction port 63 and the starting end 64a of the second discharge port 64. In addition, a second small intermediate partition 66 is formed between the start end 63a of the second suction port 63 and the terminal end 64b of the second discharge port 64.

The first suction port 53 and the first discharge port 54 in the first rotor chamber 51, and the second suction port 63 and the second discharge port 64 in the second rotor chamber 61 are of equal (identical or substantially identical) shapes. The first large intermediate partition 55 and the first small intermediate partition 56 in the first rotor chamber 51, and the second large intermediate partition 65 and the second small intermediate partition 66 in the second rotor chamber 61 have the same (the same or substantially the same) shape,

In an oil pump based on a pump housing D, a drive shaft a, a first rotor B, and a second rotor C, the first pump housing 5 and the first rotor B serve as a main pump, and the second pump housing 6 and the second rotor C serve as an auxiliary pump. The pump housing D is provided with a suction flow path and a discharge flow path, not shown, and the suction flow path is branched inside the pump housing D and communicates with the first suction port 53 and the second suction port 63, respectively, to perform a function of oil delivery.

The discharge flow path is a flow path that communicates with each of the first discharge port 54 and the second discharge port 64, and functions to discharge oil. Here, the first suction port 53 and the first discharge port 54 constitute a group, and similarly, the second suction port 63 and the second discharge port 64 constitute a group.

The set of the second suction port 63 and the second discharge port 64 of the second rotor chamber 61 is configured to be offset to the front (forward) side in the rotational direction of the drive shaft a, the first rotor B, or the second rotor C, with respect to the set of the first suction port 53 and the first discharge port 54 of the first rotor chamber 51. More specifically, in the rotation direction of the drive shaft a (or the first rotor B and the second rotor C), the set of the second suction port 63 and the second discharge port 64 is formed to be inclined toward the front (forward) side with respect to the set of the first suction port 53 and the first discharge port 54 (see fig. 1 (B) and (C) and fig. 5 (B) and (C)).

In other words, the set of the second large intermediate partitioning portion 65 and the second small intermediate partitioning portion 66 is formed at a position shifted to the front (forward) side in the rotational direction with respect to the set of the first large intermediate partitioning portion 55 and the first small intermediate partitioning portion 56 with the drive shaft a (or the first rotor B and the second rotor C) as the center. Here, a first reference line La, which is a vertical line passing through the diametrical center Pa of the shaft support hole 52, is set in the first rotor chamber 51. The first suction port 53 and the first discharge port 54 are disposed on both sides of the first reference line La. The first large intermediate partitioning portion 55 and the first small intermediate partitioning portion 56 are located on the first reference line La (see fig. 1B, 5B, and 6 a).

Further, in the second rotor chamber 61, a second reference line Lb is provided, which passes through the diametrical center Pb of the shaft support hole 62 and is inclined at an angle θ forward (forward) with respect to the first reference line La, which is a vertical line passing through the diametrical center Pb of the shaft support hole 62, in the second rotor chamber 61.

The second suction port 63 and the second discharge port 64 are disposed on both sides of the second reference line Lb. In addition, the second large intermediate partitioning portion 65 and the second small intermediate partitioning portion 66 are located on the second reference line Lb. That is, the first reference line La and the second reference line Lb are reference lines showing the offset amount as an angle.

The offset amounts of the two groups of the first suction port 53 and the first discharge port 54 of the first rotor chamber 51, and the second suction port 63 and the second discharge port 64 of the second rotor chamber 61 are preferably as follows. First, the following equation is applied to derive an angle θ by which the phase of each of the external teeth 3,. Is shifted by half a tooth in the first rotor B or the second rotor C appropriately attached to the drive shaft a.

θ＝(360／ｎ)×(1／2)

Here, n is the number of the outer teeth 3 of each of the first rotor B and the second rotor C. Therefore, when the number of the outer teeth 3 of each of the first rotor B and the second rotor C is 6, the phase shift angle θ is 30 degrees when the above equation 1 is applied.

That is, when the number of the external teeth 3 of each of the first rotor B and the second rotor C is set to 6, the set of the second suction port 63 and the second discharge port 64 of the second rotor chamber 61 is formed at a position shifted by 30 degrees toward the forward (advancing) side with respect to the set of the first suction port 53 and the first discharge port 54 of the first rotor chamber 51 with respect to the drive shaft a.

In other words, the set of the second large intermediate partitioning portion 65 and the second small intermediate partitioning portion 66 is formed at a position shifted by 30 degrees to the front (forward) side in the rotational direction with the drive shaft a as the center, with respect to the set of the first large intermediate partitioning portion 55 and the first small intermediate partitioning portion 56. The angle of the displacement is an approximate angle, and even an angle other than 30 degrees can reduce the discharge pulsation.

In addition, although not shown, when the number of the external teeth 3,. Or.. Is 8 for each of the first rotor B and the second rotor C, the set of the second suction port 63 and the second discharge port 64 of the second rotor chamber 61 is formed at a position shifted by 22.5 degrees toward the front (forward) side with respect to the set of the first suction port 53 and the first discharge port 54 of the first rotor chamber 51, centering on the drive shaft a.

By employing a configuration in which the set of the second suction port 63 and the second discharge port 64 of the second rotor chamber 61, or the first large intermediate partition 55 and the second large intermediate partition 65, is offset relative to the set of the first suction port 53 and the first discharge port 54 of the first rotor chamber 51, in such a manner as to be inclined toward the front (forward) side in the rotation direction of the drive shaft a, or the first rotor B or the second rotor C, it is possible to generate an offset in the pulsation of the discharge in the first discharge port 54 and the second discharge port 64, and reduce the vibration caused by the discharge.

The operation of the oil pump is explained in the present invention. When the pump is operated, the small chamber (inter-tooth space) S, which is based on the maximum volume state of the first rotor B and the first outer rotor 81 of the main pump, passes through the first large intermediate partition portion 55, and then the oil is discharged from the first discharge port 54 (see fig. 6 a). On the sub-pump side, the cells S of the second rotor C and the second outer rotor 82 pass through the second large intermediate partition 65 later than the first rotor B and the first outer rotor 81 (see fig. 6B). In this way, the main pump and the sub pump can prevent noise and vibration from being generated by the respective pulsation offsets during oil discharge.

In another embodiment of the drive shaft a, there is a drive shaft in which the first external fitting tooth profile A1 and the second external fitting tooth profile A2 are integrally and continuously formed in the axial direction (see fig. 8). In this embodiment, a drive shaft is formed continuously between the first external fitting tooth profile A1 and the second external fitting tooth profile A2 at a portion having the same cross-sectional shape as those of the first external fitting tooth profile A1 and the second external fitting tooth profile A2, and the intermediate shaft portion 1c is not present (see fig. 8 a).

In this embodiment, the first external fitting tooth profile portion A1 and the second external fitting tooth profile portion A2 are in phase. A portion formed between the first outer fitting tooth shape portion A1 and the second outer fitting tooth shape portion A2 is referred to as a continuous outer fitting tooth shape portion A3. The continuous external fitting tooth profile A3 is a portion that is formed between the first external fitting tooth profile A1 and the second external fitting tooth profile A2 in a substantially spline shaft shape and is integrated with the first external fitting tooth profile A1 and the second external fitting tooth profile A2.

With this configuration, the first external fitting tooth-shaped portion A1 and the second external fitting tooth-shaped portion A2 can be formed as spline-shaped shaft portions that are continuous in the axial direction, so that the shape and structure of the drive shaft a can be simplified. Therefore, in the manufacture of the drive shaft a, the first externally fitting toothed portion A1 and the second externally fitting toothed portion A2 are not formed separately from the shaft member, but they can be formed in one step to manufacture the drive shaft a. Therefore, the drive shaft a can be efficiently manufactured and provided at a low cost.

When the first rotor B and the second rotor C are assembled to the drive shaft a, the second rotor C, the spacer 7, and the first rotor B are inserted and mounted in this order from the same side with respect to the axial direction of the drive shaft a, as shown in fig. 8 (B). Specifically, the second rotor C is inserted from the first external fitting tooth profile A1 side, passes through the continuous external fitting tooth profile A3, and is disposed at the position of the second external fitting tooth profile A2.

Further, in the drive shaft a, a stopper 11 may be formed on the outer end (tip) side of the second outer fitting tooth profile A2 in order to dispose the second rotor C at the position of the second outer fitting tooth profile A2. Specifically, the stopper 11 is a portion having a disk flange shape and has a larger diameter than the second external fitting tooth portion A2. The first pump casing 5 and the second pump casing 6 can be attached from both shaft ends of the drive shaft a so as to sandwich the partition block 7 together with the first outer rotor 81 and the second outer rotor 82, thereby configuring a pump casing D.

In this embodiment, the second rotor C, the spacer 7, and the first rotor B are inserted from the first external fitting tooth profile A1 side, but the present invention is not limited to this, and a configuration may be adopted in which the second rotor C, the spacer 7, and the first rotor B are inserted from the second external fitting tooth profile A2 side of the drive shaft a. In this case, the stopper 11 is formed on the outer end (front end) side of the first external fitting tooth shape portion A1.

Description of the symbols

A drive shaft

A1 First external fitting tooth profile

A2 Second external engaging tooth profile

21. Tabling groove

22. Groove filling part

B first rotor

B1 First internally-fitted tooth portion

C second rotor

C1 Second internally-fitted tooth portion

3. External tooth

42. Missing tooth part

D pump casing

51. First rotor chamber

53. First suction port

61. Second rotor chamber

63. Second suction port

Claims

1. An oil pump is characterized by comprising: a pump casing having a first rotor chamber and a second rotor chamber and being a three-layer structure of the first pump casing, a partition block, and a second pump casing; a drive shaft provided with a first external fitting tooth profile portion in which a groove filling portion is provided in a fitting groove arranged in a circumferential direction at a predetermined interval from the fitting groove, and a second external fitting tooth profile portion having a cross-sectional shape equal to that of the first external fitting tooth profile portion, the first external fitting tooth profile portion and the second external fitting tooth profile portion being integrally and continuously formed in the axial direction; a first rotor having a first internal spline tooth-shaped portion provided with a tooth-lacking portion combined with the groove-filling portion and external teeth, and accommodated in the first rotor chamber; and a second rotor having a second internal spline portion having the same configuration as the first internal spline portion and the same number of external teeth, having a structure substantially the same and the same size as the first rotor except for a size in a thickness direction, housed in the second rotor chamber, and configured as follows:

the first rotor and the second rotor are attachable to the drive shaft only when the groove filling portion and the tooth missing portion respectively coincide, and phases of the external teeth of the first rotor and the second rotor coincide, and a set of a first suction port and a first discharge port of the first rotor chamber and a set of a second suction port and a second discharge port of the second rotor chamber have the same configuration and are offset from each other in phase,

the groove filling section is provided at an axial direction front end of the fitting groove, a stopper is formed on an outer end side of the second outer fitting tooth profile of the drive shaft, the stopper having a larger diameter than the second outer fitting tooth profile, and is inserted and assembled in order of the second rotor, the spacer block, and the first rotor from the first outer fitting tooth profile of the drive shaft, or a stopper is formed on an outer end side of the first outer fitting tooth profile of the drive shaft, the stopper having a larger diameter than the first outer fitting tooth profile, and is inserted and assembled in order of the first rotor, the spacer block, and the second rotor from the second outer fitting tooth profile of the drive shaft.

2. The oil pump according to claim 1, characterized by adopting a configuration in which a first large-to-medium partition between a terminal end of the first suction port and a starting end of the first discharge port and a second large-to-medium partition between a terminal end of the second suction port and a starting end of the second discharge port are shifted in phase from each other.

3. The oil pump according to claim 1 or 2, characterized in that an amount of a difference in phase between the group of the first suction port and the first discharge port, and the group of the second suction port and the second discharge port is set to an amount of half a tooth of the outer teeth of the rotor.

4. The oil pump according to claim 1 or 2, wherein the groove filling portion is provided at a height from a bottom surface of the fitting groove to a substantially middle portion in a tooth dimension direction.

5. The oil pump according to claim 1 or 2, wherein the groove filling portion is provided at a height from a bottom surface of the fitting groove to a top portion in a tooth dimension direction.