JP2015121210A - Oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oil pump which further increases a variable rate of a discharge amount, further reduces the wasteful work of an engine and the pump, and improves fuel economy.SOLUTION: An oil pump comprises an inner rotor 3, an outer rotor 4, an outer ring 5, and a suction port 12 and a discharge port 13, sets a clearance between a terminal end 12b of the suction port 12 and a starting end 13a of the discharge port 13 as a first seal land 14, and is composed of a housing A having a rotor chamber for accommodating the inner rotor 3, the outer rotor 4 and the outer ring 5. A final position eccentric axial line Lx which connects a rotation center of the inner rotor 3 and a rotation center of the outer rotor 5 by the oscillation of the outer ring 5 at an angle from an initial position to a final position can turn in a region of an angle which exceeds 90 degrees at the suction port side with respect to an initial position eccentric axial line La.

Description

  The present invention is capable of further increasing the variable rate of the discharge amount in an oil pump having a variable discharge amount mounted on a vehicle engine or the like, and further reducing unnecessary work in the engine and the pump. The present invention relates to an oil pump that can improve fuel consumption.

  Conventionally, there are various oil pumps that can vary the discharge amount. Among them, there is an oil pump with an inscribed rotor. Generally, an internal gear type oil pump rotates while an inner rotor having external teeth and an outer rotor having internal teeth mesh with each other. A space called a cell is formed between the teeth of the inner rotor and the teeth of the outer rotor.

  And in the operation | movement which an inner rotor and an outer rotor rotate, 180 degrees out of rotation angle 360 degrees suck | inhales oil because the volume of a cell increases. The remaining 180 ° discharges oil by reducing the volume of the cell. In a normal internal gear type oil pump that is not a variable capacity type, the suction port is arranged at a phase where the cell volume increases, and the discharge port is arranged at a phase where the cell volume decreases.

  By the way, in the oil pump in which the discharge amount is variable, an adjustment member is provided to move the outer rotor along a predetermined locus, and the outer rotor is rotatably mounted on the adjustment member. The center of rotation of the outer rotor is moved by swinging the adjustment member. Patent Documents 1 to 4 exist as this type.

WO2010 / 013625 Publication JP-A-10-169571 Japanese Patent Application Laid-Open No. 08-159046 JP 2008-298026 A

  Specifically, in Patent Document 1 (WO2010 / 013625), in paragraph 0006, “a rocker lever for operating the adjustment ring 14 is supported swingably on the casing portion 1, and the rocker lever is swung. In the state where the inner tooth row 24 'and the outer tooth row 24 are engaged with each other, the rotation shaft of the outer rotor 4 moves by 90 degrees in the direction opposite to the inner rotor 3. This movement causes the inner rotor 3 and the outer rotor 4 to move. The positional relationship between the low pressure port 8 and the high pressure port 9 with respect to the ring gear set 5 changes, and adjustment from the maximum discharge amount of the pump to zero discharge amount is possible.

  In Patent Document 2 (Japanese Patent Laid-Open No. 10-169571), in paragraph 0037, “Adjustment ring 14 is relatively small in a state where two tooth rows 24 and 24 ′ of adjustment gear 20 are continuously meshed with each other. When the tooth base circle 15 of the adjustment ring 14 and the tooth base circle 16 of the inner tooth row 24 ′ rotate on each other with zero slip by rotating in the rotational direction D of the inner rotor 3 by the angle γ, the external rotor The rotational axis 4 is moved from the position shown in FIG. 1 (a) to the position shown in FIG. 1 (b) by 90 ° around the rotational axis of the internal rotor 3 in the direction opposite to the rotational position of the internal rotor 3. The position shown in Fig. 1 (b) is the zero position of the pump, and ideally no fluid is discharged in this position, where the groove ports 8 and 9 are on both sides of the full and open mesh positions. Extend symmetrically. It has been described as.

  In Patent Document 3 (Japanese Patent Laid-Open No. 08-159046), in paragraph 0023, “the rotational center position of the outer rotor 4 rotatably held in the cam ring 5 by such a swinging movement of the cam ring 5 is The internal gear pump tooth height is the revolution diameter, the rotation center position of the inner rotor 3 is the revolution center, the revolution is 90 degrees clockwise, and the volume of the oil transfer reservoir 11 on the vicinity 22 at the end of the suction region 21 Is minimized. "

  In Patent Document 4 (Japanese Patent Application Laid-Open No. 2008-298026), in paragraph 0055, “the pump discharge pressure acting on the adjustment ring 7 further increases as the pump rotation speed increases. As shown in FIG. 11, it further rotates counterclockwise against the spring force of the spring member 27 and rotates to an angle of about 30 degrees.

  For this reason, the center point E of the outer rotor 5 has moved by approximately 90 °, and the eccentric direction with respect to the inner rotor 4 is at an angular position of approximately 90 degrees. For this reason, in the pump chamber 10, the volume when passing the seal land portion 15 from the suction chamber 11 to the discharge chamber 12 is substantially equal to the volume when passing the seal land portion 16 from the discharge chamber 12 to the suction chamber 11. The pump discharge amount is minimized. Is described.

  In Patent Document 1 to Patent Document 4, the following operation is disclosed in order to change the discharge capacity of the oil pump. Here, FIG. 6 is a schematic diagram for explaining the contents of Patent Documents 1 to 4. In order to maximize the discharge capacity of the oil pump, the suction port a is arranged in a phase where the volume of the cell is increased, and the discharge port b is arranged in a phase where the volume of the cell is reduced. This is the initial position of the outer rotor c [see FIG. 6 (A)]. At this time, the eccentric axis k is vertical in FIG.

  Then, the one tilted by the angle θo with respect to the eccentric shaft k at the initial position becomes the eccentric shaft k at the final position. Here, the eccentric shaft k is inclined by 90 degrees, which is the final position of the outer rotor c. Inside both the discharge port b and the suction port a, the suction amount and the discharge amount of the moving cell are substantially equal, so that the suction amount and the discharge amount cancel each other and oil does not flow. Thereby, the discharge capacity can theoretically be zero. As described above, in Patent Documents 1 to 4, when the discharge capacity of the oil pump is theoretically zero, it is common technical knowledge to tilt the eccentric shaft k by 90 ° [FIG. 6 (B). reference〕.

  That is, in Patent Documents 1 to 4, when the eccentric shaft k is inclined by 90 ° with respect to the initial position, the rotation by the inner rotor d and the outer rotor c causes the discharge port b and the suction port a to be inside. The amount of sucking the oil in the cell passing through and the amount of discharging are substantially equal. That is, the amount of oil sucked by the cell and the amount of discharge are substantially equal, canceling each other, so that the oil does not flow.

  However, when the applicant actually performed the test with the eccentric shaft tilted 90 degrees, the oil flowed about 25% of the maximum discharge amount. Accordingly, the variable rate of the discharge amount is 75% and does not become zero. This means that the improvement in fuel consumption is reduced by reducing the variable range of the discharge capacity.

  Thus, there is a cause that the discharge capacity of the oil pump cannot actually be zero even if the eccentric shaft k is inclined by 90 degrees. This cause is shown below. First, in the pump, the oil in the flow state always tries to continue to flow in the forward direction from the suction side to the discharge side. If you keep the engine running, the oil will always flow in the forward direction.

  The oil has a mass, and the oil flowing in the forward direction in the pump maintains a forward flow state according to its inertia. Even if the pump works in the reverse direction (when the eccentric axis exceeds 90 degrees), if the function is very small, the oil flow direction does not change and continues to flow in the forward direction. For this reason, even if the eccentric shaft k is rotated 90 degrees, the discharge amount is reduced, but the forward oil flow does not become zero, and the pump oil discharge is continued.

  Next, as a cause of the discharge capacity of the oil pump not becoming zero even when the eccentric shaft k is tilted by 90 degrees, cavitation occurring in the pump can be mentioned. When the eccentric shaft k rotates 90 degrees, the arrangement is as shown in FIG. 6B, and the configuration is vertically symmetrical about the eccentric shaft k.

  With the eccentric shaft k rotated 90 degrees and horizontally disposed (see FIG. 6B), seal lands (partition portions) are disposed on both the upper and lower sides around the eccentric shaft k. . When the inner rotor and the outer rotor rotate counterclockwise in such a state, the volume of the cell gradually decreases below the eccentric shaft k disposed horizontally on the discharge port b side of the pump. Thus, since the volume of the cell gradually expands above the eccentric axis k, the suction operation is performed.

  At this time, in the process of reducing the volume of the cell, the oil is surely discharged by the amount that the volume of the cell is reduced. That is, in the discharge port b, the oil in the cell is discharged almost completely during the contraction process of the cell moving counterclockwise. On the other hand, in the expansion process of the cell that moves counterclockwise in the discharge port b, the cell whose volume increases may not be sufficiently filled with oil. In particular, as the rotational speed of the rotor increases, a void portion in which a part of the cell is not filled with oil is likely to be generated.

  Furthermore, when the volume of the cell that moves counterclockwise as it is increases and a part of the cell reaches the seal land where no oil exists, the cell cannot absorb the oil, and the vacuum region in the cell Will occur. In this way, especially when the cell moves at a high speed and the volume is increased, it becomes difficult for the oil to flow in, and the vacuum region increases. As a result, a large number of bubbles (micro vacuum bubbles) are generated from the oil in the cell. Occur.

  This phenomenon is so-called cavitation, and even if a part of the cell exists in the discharge port b, the cell cannot suck oil due to a large number of bubbles. In particular, the probability that cavitation will occur increases due to the fact that cells begin to intersect the seal land and the volume of the cells further expands.

  Therefore, in the state of the art, in the state where the eccentric shaft k is rotated 90 degrees, in the discharge port b side, in the oil discharge operation of the cell whose volume is contracted and the oil suction operation of the cell whose volume is expanded, The oil discharge amount by the cell is larger than the suction amount. As a result, the oil discharge amount and the suction amount in the discharge port b are not equal and cannot be completely offset.

  Moreover, the amount of oil discharged by the cell in the discharge port b is larger than the amount of intake, and therefore, even if the eccentric shaft k rotates 90 degrees, the oil discharge amount is reduced overall, but the oil is forward. However, this flow does not stop, and as a result, it is not possible to desire a variable rate of the discharge amount as expected. Therefore, an object of the present invention (technical problem to be solved) is to further increase the variable rate of the discharge amount in the operation of changing the discharge amount by rotating the eccentric shaft.

  In view of the above, the inventor has intensively and intensively studied to solve the above-described problems. As a result, the inventor of claim 1 has the inner rotor having the outer teeth, the inner teeth forming the cells together with the outer teeth, and the inner. An outer rotor that rotates with a predetermined amount of eccentricity with respect to the rotation center of the rotor, and a rotation center of the outer rotor that swings with respect to the rotation center of the inner rotor according to a locus circle whose radius is the amount of eccentricity. An outer ring, a suction port and a discharge port, and a first seal land between the end portion of the suction port and the start end portion of the discharge port and storing the inner rotor, the outer rotor, and the outer ring In an oil pump comprising a pump housing having a rotor chamber for rotating, the angle of the outer ring from the initial position to the final position is varied. Thus, the final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor can rotate a region having an angle exceeding 90 degrees toward the suction port side with respect to the initial position eccentric axis. By solving the above problem, the above problems were solved.

  The final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by the swing of the outer ring from the initial position to the final position of the outer ring according to the invention of claim 2 is: The above problem has been solved by providing an oil pump that can rotate in an area of an angle of more than 90 degrees to an angle of 150 degrees toward the suction port side with respect to the initial position eccentric axis. The final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by swinging from the initial position of the outer ring to the final position in the invention of claim 3 according to claim 1, The above-described problem has been solved by providing an oil pump that can rotate in the region of an angle of 100 degrees to 140 degrees toward the suction port side with respect to the initial position eccentric axis.

  In the first aspect of the invention, the final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by the swinging of the outer ring from the initial position to the final position is relative to the initial position eccentric axis. Thus, by enabling the rotation of the region having an angle of more than 90 degrees on the suction port side, the discharge amount can be further reduced when the eccentric axis of the inner rotor and the outer rotor becomes the final position eccentric axis. The variable rate of the discharge capacity can be increased to about 80% or more. Therefore, it is possible to reduce unnecessary work of the pump and improve fuel efficiency.

  In the invention of claim 2, the final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by swinging from the initial position to the final position of the outer ring is relative to the initial position eccentric axis. Accordingly, the suction port can be rotated in an area of an angle of more than 90 degrees to 150 degrees. Therefore, in the process in which the engine changes from the low speed range to the high speed range, the position change of the maximum volume cell is in the range from the initial position eccentric axis to the final position eccentric axis exceeding 90 degrees from 150 degrees. Done in Thereby, the variable rate of the oil discharge amount can be made higher than before. Moreover, the variable rate of the oil discharge amount can be changed to a desired value by changing the rotation angle of the outer ring.

  In the invention of claim 3, the final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by the swinging of the outer ring from the initial position to the final position is relative to the initial position eccentric axis. Thus, it can be rotated in the region of an angle of 100 to 140 degrees toward the suction port. Thereby, the variable rate of the oil discharge amount can be performed with high accuracy. Moreover, the variable rate of the oil discharge amount can be changed to a desired value by changing the rotation angle of the outer ring.

(A) The principal part expanded sectional view which shows the initial position of the outer ring of this invention, an outer rotor, and an inner rotor, (B) is an enlarged view which shows the structure of a fan-shaped rotation locus vicinity. It is a principal part expanded sectional view which shows the final position of the outer ring of this invention, an outer rotor, and an inner rotor. It is a schematic diagram showing the composition in the present invention. It is a graph which shows the characteristic of this invention and a prior art. (A) The principal part expanded sectional view of the state which rotated the phase of the outer rotor of this invention 90 degree | times clockwise with respect to the initial position eccentric axis, (B) is an inner rotor and an outer rotor in the state of (A). The figure of the state rotated only a slight angle, (C) is the (α) part enlarged view of (B). (A) is a schematic diagram showing the initial position state of the outer rotor in the prior art, and (B) is a schematic diagram showing the final position state of the outer rotor in the prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the present invention mainly includes a pump housing A, an inner rotor 3, an outer rotor 4, an outer ring 5, and an operating means 9. A rotor chamber 1 is formed in the pump housing A. A shaft hole 11 in which a drive shaft for driving the pump is mounted is formed in the bottom surface portion of the rotor chamber 1, and a suction port 12 and a discharge port 13 are formed around the shaft hole 11. A seal land is formed between the suction port 12 and the discharge port 13.

  The seal lands are formed at two locations in the rotor chamber 1, one of which is located between the end portion 12 b of the suction port 12 and the start end portion 13 a of the discharge port 13, and this seal land is the first seal. This is called land 14.

  The other seal land is located between the end portion 13 b of the discharge port 13 and the start end portion 12 a of the suction port 12, and is referred to as a second seal land 15. The pump housing A is formed with an operation chamber 2 continuous to the rotor chamber 1, and an operation protrusion 51 of an outer ring 5 to be described later is disposed. In the rotor chamber 1, an inner rotor 3, an outer rotor 4, and an outer ring 5 are provided.

  The inner rotor 3 is a gear having a trochoidal shape or a substantially trochoidal shape, and has a plurality of external teeth 31, 31,... (See FIGS. 1 to 3). Further, a boss hole 32 for a drive shaft is formed at the central position in the diameter direction, and the drive shaft 33 is fixedly passed through the boss hole 32. The boss hole 32 is formed as a non-circular shape, and a shaft fixing portion having substantially the same shape as the boss hole 32 is fixed to the inner rotor 3 by fixing means such as press-fitting or two-surface width. It is rotated by the rotation drive.

  The outer rotor 4 is formed in an annular shape, and a plurality of inner teeth 41, 41,... Are formed on the inner peripheral side. The number of outer teeth 31 of the inner rotor 3 is configured to be one less than the number of inner teeth 41 of the outer rotor 4. The outer teeth 31, 31,... Of the inner rotor 3 and the inner teeth 41, 41,.

  The rotation center of the inner rotor 3 is Pa. The position of the rotation center Pa does not move with respect to the rotor chamber 1. The rotation center of the outer rotor 4 is Pb. A virtual line connecting the rotation center Pa and the rotation center Pb is referred to as an eccentric axis. The eccentric axis includes an initial position eccentric axis La and a final position eccentric axis Lx according to the positions of the outer rotor 4 and the outer ring 5.

  The distance between the rotation center Pa of the inner rotor 3 and the rotation center Pb of the outer rotor 4 is referred to as an eccentricity e. Then, a locus circle is formed with the center of rotation Pa of the inner rotor 3 and the radius of the eccentricity e. By operating the outer ring 5, the rotation center Pb of the outer rotor 4 moves along a fan-shaped arc that is a part of the locus circle from the initial position state to the final position state (see FIG. 1B). . The arc-shaped locus portion of the rotation center Pb at this time is referred to as a fan-shaped rotation locus Q.

  The outer ring 5 is formed in a substantially annular shape, and is provided with an operation protruding portion 51 that is formed to protrude outward in the diameter direction from a predetermined location on the outer peripheral side surface 5a. Further, a holding inner peripheral portion 52 which is a perfect circular through hole is formed on the inner side of the outer ring 5. The outer ring 5 is oscillated in the rotor chamber 1 by the operation means 9 described later through the operation protrusion 51. The operation protrusion 51 is disposed in the operation chamber 2 and can swing within the operation chamber 2.

  The holding inner peripheral portion 52 is formed as a circular inner wall surface, and the inner diameter of the holding inner peripheral portion 52 is substantially the same as the outer diameter of the outer rotor 4. The inner diameter of the peripheral portion 52 is slightly larger than the outer diameter of the outer rotor 4, and a clearance is provided between the holding inner peripheral portion 52 and the outer rotor 4 so that the outer rotor 4 can rotate smoothly. Inserted.

  The position of the diameter center Pc of the holding inner peripheral portion 52 of the outer ring 5 coincides with the rotation center Pb of the outer rotor 4 inserted in the holding inner peripheral portion 52 (see FIG. 2). The outer ring 5 is disposed in the rotor chamber 1, the outer rotor 4 is disposed in the holding inner peripheral portion 52, the outer rotor 4 is rotatably supported, and the operation ring 9 described later is used to operate the outer ring 5. It swings along the fan-shaped rotation trajectory Q (see FIGS. 1 and 2).

  The outer ring 5 is housed in the rotor chamber 1 of the pump housing A and is configured to be swingable within the rotor chamber 1. Therefore, the rotor chamber 1 is formed slightly wider than the outer shape of the outer ring 5, and an extra space is provided for the outer rotor 4 to swing. The outer ring 5 is oscillated by the operating means 9, but the locus of the oscillation is fixed, and the diameter center Pc of the holding inner peripheral portion 52 oscillates along the fan-like rotation locus Q. To do.

  In the present invention, the inner rotor 3 and the outer rotor 4 have an initial position and a final position, and the initial position is a cell in a plurality of cells S, S,... Formed by the inner rotor 3 and the outer rotor 4. It means the position of the inner rotor 3, the outer rotor 4 and the outer ring 5 when the maximum cell Sa in which the volume of S is maximum is located on the first seal land 14. Further, at the initial position, the engine speed is mainly in a low speed range. An eccentric axis connecting the rotation center Pa of the inner rotor 3 and the rotation center Pb of the outer rotor 4 at this initial position is referred to as an initial position eccentric axis La (see FIG. 1).

  The final position is when the outer ring 5 swings to the maximum from the initial position, the rotation center Pb of the outer rotor 4 moves along the fan-shaped rotation trajectory Q, and the position of the maximum cell Sa moves to the maximum. The position of the outer ring 5, the inner rotor 3, and the outer rotor 4 is said. At this time, the number of revolutions of the engine is in a middle rotation range and a high rotation range. The eccentric axis connecting the rotation center Pa of the inner rotor 3 and the rotation center Pb of the outer rotor 4 at this final position is referred to as a final position eccentric axis Lx (see FIG. 2).

  The angle at which the initial position eccentric axis La of the outer rotor 4 that actually swings by the outer ring 5 swings from the initial position eccentric axis Lx is θ, and the angle at which the operation projection 51 of the outer ring 5 swings at this time. Is θa, the angle θa is much smaller than the angle θ.

  That is, the outer ring 5 only slightly swings the operation projection 51 by the operating means 9, and the maximum swing angle of the outer rotor 4, that is, the angle formed between the initial position eccentric axis La and the final position eccentric axis Lx is extremely large. can do. Specifically, the swing angle of the operation protrusion 51 is about 15 degrees, and the angle between the initial position eccentric axis La and the final position eccentric axis Lx of the outer rotor 4 can be about 120 degrees ( 1 and 2).

  When the outer ring 5 actually swings from the initial position to the final position, the eccentric axis swings in the region of the angle θ formed by the initial position eccentric axis La and the final position eccentric axis Lx. Thus, the eccentric axis swings in the region of the angle θ. The angle θ is an angle exceeding 90 degrees, that is, 90 degrees is not included. Therefore, the angle θ formed by the initial position eccentric axis La and the final position eccentric axis Lx is an obtuse angle.

  Next, the range of the angle θ is such that the angle θ exceeds 90 degrees and is within about 150 degrees. In this embodiment, when the final position eccentric axis Lx is about 150 degrees with respect to the initial position eccentric axis La, the maximum cell Sa exists in the region of the suction port 12. Next, the range of the angle θ is limited so that the final position eccentric axis Lx can rotate in the region of an angle of about 100 degrees to about 140 degrees toward the suction port 12 with respect to the initial position eccentric axis La. There is also. In the present invention, the most optimal angle θ of the final position eccentric axis Lx with respect to the initial position eccentric axis La is about 120 degrees. Thereby, the oil pump of the present invention operates as follows.

  First, a small amount of oil is sucked from the start end portion 12 a side of the suction port 12, and when the cell S passes through the position where the maximum cell Sa is reached, a large amount of oil is discharged into the suction port 12. Then, a small amount of water is discharged from the position of the discharge port 13 closer to the start end portion 13a to the position where the cell S becomes the minimum cell Sb, and a large amount of oil is sucked from the discharge port 13 after passing through this position. And as for the discharge amount, oil of about 20% or less of the maximum discharge amount flows in the forward direction. As a result, the variable rate can be about 80% or more (see FIG. 4).

  The outer ring 5 has a first pressure-receiving surface 51a formed on one side in the swing direction of the operation protrusion 51 and a second pressure-receiving surface 51b formed on the other side. The elastic pressing portion 8 provided in the operation chamber 2 elastically presses the second pressure receiving surface 51b to generate a load that always puts the outer ring 5 and the outer rotor 4 at the initial positions.

  A first oil passage 21 and a second oil passage 22 are provided between the operation means 9 and the operation chamber 2. The operation means 9 can apply hydraulic force to the first pressure receiving surface 51 a and the second pressure receiving surface 51 b of the operation protrusion 51 in the operation chamber 2. By operating the hydraulic pressure of the operating means 9, the operating protrusion 51 is swung by the pressure difference between the hydraulic pressure applied to the first pressure receiving surface 51 a and the second pressure receiving surface 51 b of the operating protrusion 51 and the elastic pressing force of the elastic pressing portion 8. It is something to be made. As a result, the operating means 9 swings the outer ring 5 (see FIGS. 1 to 3).

  The swinging guide operation of the outer ring 5 is performed by a plurality of tooth profile portions 6 provided between the rotor chamber 1 and the outer ring 5. The tooth profile 6 includes an outer position tooth profile 6 b formed in the rotor chamber 1 and an inner position tooth profile 6 a formed on the outer peripheral side surface of the outer ring 5. Specifically, a solenoid valve or the like is used as the operating means 9 of the outer ring 5. In the drawing, reference numeral 7 denotes a seal portion, which serves to block the gap between the rotor chamber 1 and the outer ring 5.

  FIG. 5A shows that in the present invention, the eccentric axis Lm connecting the rotation center Pa of the inner rotor 3 and the rotation center Pb of the outer rotor 4 moves 90 degrees in the clockwise direction with respect to the initial position eccentric axis La. As a result, the outer rotor 4 is out of phase. At this time, the position of the diameter center Pc of the inner circumferential portion 52 of the outer ring 5 and the rotation center Pb of the outer rotor 4 are naturally aligned. Due to the phase shift, the maximum cell Sa intersects the eccentric axis Lm moving in the clockwise direction with respect to the initial position eccentric axis La [see FIG. 5 (A)].

  Then, immediately after the engine is started, initially, as shown in FIG. 1, the rotation center Pb of the outer rotor 4 is at the initial position, and the maximum cell Sa intersects on the initial position eccentric axis La. At this time, the oil flows in the forward direction from the suction port 12 to the discharge port 13. This forward flow of oil is maintained even when the eccentric axis Lm moves 90 degrees in the clockwise direction with respect to the initial position eccentric axis La.

  In other words, since oil has a mass, oil tends to continue to flow in the forward direction due to its inertia. The oil has a momentum to flow in the forward direction, and when the phase of the outer rotor 4 is shifted and the cell S performs the oil discharge and suction operations within the range of the discharge port 13, Momentum is applied to the discharge operation, the oil discharge amount exceeds the suction amount, and the forward flow of the oil is eventually maintained.

  Then, as the eccentric axis Lm approaches the final position eccentric axis Lx, the contraction operation of the volume of the cell S within the range of the discharge port 13 does not exist, oil is not discharged, and vice versa. The volume expansion operation is increased, and only the oil is sucked. Therefore, a part of the oil flows backward from the discharge port 13 to the suction port 12, and the forward flow becomes zero at a predetermined angle exceeding 90 degrees.

  The above operation can also be explained by applying cavitation generation (see FIGS. 5B and 5C). That is, when the eccentric axis Lm is rotated 90 degrees and the phase of the outer rotor 4 is shifted, the inner rotor 3 and the outer rotor 4 are vertically symmetrical about the eccentric axis Lm, and both the upper and lower sides of the eccentric axis Lm In this configuration, the first seal land 14 and the second seal land 15 are arranged.

  Then, as the inner rotor 3 and the outer rotor 4 rotate counterclockwise, the volume of the cell S is gradually reduced below the eccentric axis Lm disposed horizontally within the range of the discharge port 13, and oil is reduced. Discharging, the volume of the cell S gradually expands above the eccentric axis Lm, and sucks oil (see part (α) in FIG. 5B).

  At this time, in the process of reducing the volume of the cell S, the oil is surely discharged by the amount that the volume of the cell S is reduced. However, in the process of increasing the volume of the cell S and trying to suck the oil, the cell S The oil is not enough inside. In particular, as the rotational speed of the rotor increases, a void portion that is not filled with oil tends to be generated in a part of the cell S.

  Furthermore, if the volume of the cell S that moves counterclockwise as it is increases and the cell S begins to intersect the second seal land 15 where no oil exists, the cell S cannot sufficiently absorb the oil. A vacuum region is generated in the cell S. As the cell S moves, the vacuum region continues to increase, and a large number of bubbles q, q,..., That is, cavitation occurs (see FIG. 5C).

  Further, when the intersection between the cell S and the second seal land portion 15 is increased, more bubbles q, q,... Are generated, and even if the negative pressure in the cell S increases, the large number of bubbles q, q,... impedes oil inhalation and reduces the oil inhalation of the cell S. As a result, within the range of the discharge port 13, the oil discharge amount by the cell S exceeds the suction amount or only discharge is performed, and the forward flow of oil is maintained.

  Moreover, although the oil flow in the forward direction is maintained, the total discharge amount of the pump is reduced. As a result, when the eccentric axis Lm is rotated more than 90 degrees with respect to the initial position eccentric axis La, the rotation range of the eccentric axis Lm that can further reduce the discharge amount is increased, and a large variable rate can be obtained. it can.

A ... pump housing, 1 ... rotor chamber, 12 ... suction port, 13 ... discharge port,
14 ... 1st seal land, 3 ... Inner rotor, 4 ... Outer rotor,
5 ... outer ring, Pa ... center of rotation of inner rotor,
Pb ... rotation center (outer rotor), La ... initial position eccentric axis,
Lx: Final position eccentric axis.

Claims (3)

An inner rotor having outer teeth, an outer rotor having inner teeth that form cells together with the outer teeth and rotating with a predetermined amount of eccentricity relative to the rotation center of the inner rotor, and the rotation center of the inner rotor An outer ring in which the rotation center of the outer rotor swings in accordance with a locus circle having the radius of the eccentric amount, a suction port and a discharge port, and a terminal end portion of the suction port and a start end portion of the discharge port In an oil pump comprising a pump housing having a first seal land between and a rotor chamber that houses the inner rotor, the outer rotor, and the outer ring,
The final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by the swing of the angle from the initial position to the final position of the outer ring is the suction position relative to the initial position eccentric axis. An oil pump characterized in that a region having an angle of more than 90 degrees can be rotated on the port side.   The final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by swinging from the initial position to the final position of the outer ring is defined in claim 1 with respect to the initial position eccentric axis. An oil pump characterized in that it can be rotated in the region of an angle of more than 90 degrees to 150 degrees on the suction port side.   The final position eccentric axis connecting the rotation center of the inner rotor and the rotation center of the outer rotor by swinging from the initial position to the final position of the outer ring is defined in claim 1 with respect to the initial position eccentric axis. An oil pump characterized in that it can be rotated in the region of an angle of 100 to 140 degrees toward the suction port.

Images