JP2016102490A - Variable displacement oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement oil pump capable of increasing a degree of freedom in size in a radial direction of the oil pump.SOLUTION: This invention comprises an inner rotor 3; an outer rotor 4 rotated with a prescribed eccentricity [e] in respect to a rotation center Pa of the inner rotor 3; an outer ring 5 oscillated with a rotation center Pb of the outer rotor 4 in respect to a center of rotation Pa of the inner rotor 3 with the eccentricity [e] being applied as a radius; and a pump housing A having a rotor chamber 1 storing the inner rotor 3, outer rotor 4 and outer ring 5. A tooth depth Tha of an outer tooth row 6 of the rotor chamber 1 and a tooth depth Thb of an inner tooth row 7 of the outer ring 5 are defined as Tha=2X[e+α] and Thb=2X[e+α], where [e] is an eccentricity between the rotation center Pa of the inner rotor 3 and the rotation center Pb of the outer ring 5 in the rotor chamber 1 and [α] is a positive correction value that is added.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable displacement oil pump that can increase the degree of freedom in the size of the oil pump in the radial direction.

  Conventionally, there is a variable displacement oil pump that includes an inner rotor, an outer rotor, and an outer ring. The outer ring is configured to change the discharge amount by changing the mutual phase between the inner rotor and the outer rotor by changing the rotation center position of the outer rotor. Patent Document 1 exists as the same kind of such a variable displacement oil pump.

  Although no special description is given in Patent Document 1, generally, the relationship between the tooth profile of the outer ring and the tooth profile of the pump housing is designed as shown below. FIG. 5 is a diagram for explaining Patent Document 1. In FIG. Here, in the tooth profile of the outer ring and the tooth profile of the pump housing, the pitch circle of the tooth profile of the outer ring and the pitch circle of the pump housing are in contact with each other in an ideal state. Because it is vacant, it does not touch completely.

In order for two pitch circles to touch each other, the following conditions are set.
Rhj: Pitch circle diameter of pump housing Ror: Pitch circle diameter of outer ring e: Eccentric amount Tip clearance: Ctip

Under the above conditions,
Rhj = Ror + 2 × e + 2 × Ctip
This is the relational expression.
In general,
Pitch circle diameter = (tooth diameter + root diameter) ÷ 2
And
Tooth tip diameter-tooth root diameter = 4 × e
There is a relationship.

Rewriting the above formula,
Tip diameter = root diameter + 4 x e
There is also a relationship.

Therefore, the pitch circle diameter Ror of the outer ring is
Ror = (the root diameter of the outer ring) + 2 x e

The pitch circle diameter Rhj of the pump housing is
Rhj = (pump housing tooth bottom diameter) −2 × e
It becomes.
Further, the tooth height is a distance from the pitch circle to the tooth bottom and from the pitch circle to the tooth tip.
Therefore,
The relationship of tooth height = 2 × eccentricity also holds.

JP-A-10-169571

  About the patent document 1, the content is outlined along FIG. In the following description, reference numerals are used with parentheses attached to the reference numerals used in Patent Document 1. In Patent Document 1, in order to enable the adjustment ring (14) and the casing to rotate with zero slip, as described in Paragraph [0036], “Furthermore, the root circle of the inner dentition (24 ′) The difference between the diameter and the diameter of the root circle of the outer dentition (24) is twice that of the eccentricity (17). " That is, the eccentricity (17) is the distance between Pm and Pn, where Pm is the rotation center of the inner rotor (3) and Pn is the rotation center Pn of the adjustment ring (14) in FIG.

  Furthermore, as described in paragraph [0028] of Patent Document 1, “when the tooth row between the adjustment ring and the casing portion is manufactured by sintering, an annular or inner cycloid in the annulus This requirement is satisfied if the trochoidal dentition has a tooth shape. "

  Considering in detail about Patent Document 1, when a trochoid curve is used for the outer dentition (24), the diameter of the root circle of the inner dentition (24 ') and the root circle of the outer dentition (24) The difference from the diameter is exactly twice (positive integer) the eccentricity (17). In other words, it is impossible to make it 1.8 times or 2.2 times, and anything other than 2 times is not allowed.

  This is because when the size (= the amount of eccentricity) of the eccentricity (17) of the inner rotor (3) (inner rotor) and the outer rotor (4) (outer rotor) is determined, the outer tooth row (24 ) And the inner dentition (24 ') of the casing are also uniquely determined, which means that it is difficult to adjust the size. That is, when the amount of eccentricity between the inner rotor and the outer rotor is determined, the size of the oil pump in the radial direction is inevitably determined.

  This means that, conventionally, it is difficult to adjust the size (physique and size) of the oil pump, and the design freedom of the size of the oil pump is low. Accordingly, an object of the present invention (technical problem to be solved) is to reduce the size of the internal gear type variable displacement oil pump without limiting the design condition by the amount of eccentricity of the rotation center position between the rotors. It is to provide a variable displacement oil pump having a high degree of freedom.

  Accordingly, as a result of earnest and research, the inventors have rotated the invention of claim 1 with a predetermined amount of eccentricity with respect to the inner rotor and the center of rotation of the inner rotor. An outer rotor, an outer ring that causes the rotation center of the outer rotor to swing with respect to the rotation center of the inner rotor with the eccentric amount as a radius, and a rotor chamber that houses the inner rotor, the outer rotor, and the outer ring. And a tooth height Thha of the outer dentition of the rotor chamber and a tooth height Thb of the inner dentition of the outer ring are the rotation center of the inner rotor and the center of the outer ring in the rotor chamber. And “Tha = 2 × (e + α)” and “Thb = 2 × (e + α)” by adding a positive correction value α. And by having a variable capacity oil pump comprising, the above-mentioned problems are eliminated.

  In the invention of claim 2, in claim 1, the tip circle diameter Rtb of the inner dentition of the outer ring is Rtb = Rbo + 4 × (e + α), where Rbo is the root circle diameter of the outer ring. The above problem was solved by using a variable displacement oil pump.

  In the invention of claim 3, the tip diameter Rta of the outer tooth row of the rotor chamber in the invention is defined as Rta = Rbo + 4 × where Rbo is the diameter of the bottom circle of the outer ring and Ctip is the tip clearance. The above problem was solved by using a variable displacement oil pump of (e + α) -2 × e + 2 × Ctip. The invention of claim 4 is the variable displacement oil pump according to claim 1, wherein the number of teeth of the inner teeth row of the outer ring and the outer teeth row of the rotor chamber is 6 or 8. Settled.

  In the invention of claim 1, the tooth profile of the inner dentition of the outer ring and the radial size (so-called tooth height) of the tooth profile of the outer dentition of the rotor chamber of the pump housing are the correction values α of the eccentricity e. By increasing or decreasing the value, the degree of freedom in design can be increased. Therefore, by increasing or decreasing the correction value α of the eccentricity e, the size (physique and size) of the oil pump can be changed in conjunction with each other, so that the degree of freedom of the layout in which the oil pump is mounted is improved. I can do it.

  In the present invention, the tooth profile of the inner dentition of the outer ring and the tooth profile of the outer dentition of the rotor chamber of the pump housing do not use all regions of each tooth profile, but only a part of the regions. Contact. Therefore, it is not necessary to manufacture all the regions of the inner teeth row and the outer teeth row with high accuracy, and only the angle regions belonging to the contact range in the tooth shape may be manufactured with high accuracy.

  Therefore, even if the manufacturing accuracy of the tooth profile in the other region other than the contact region of the tooth profile is low, the outer ring can be rotated smoothly, and the manufacturing cost can be reduced. In other words, for example, if only approximately half teeth or 1/3 teeth are manufactured with high accuracy in one tooth profile, it can be sufficiently used even if the manufacturing accuracy of the other tooth profile portions is low.

  In claim 2, the tip circle diameter Rtb of the inner dentition of the outer ring is set such that Rbo is the root diameter of the outer ring, and Rtb = Rbo + 4 × (e + α). The diameter can be changed while keeping the meshing state between the row and the outer tooth row of the rotor chamber good.

  According to a third aspect of the present invention, the tip circle diameter Rta of the outer dentition of the rotor chamber is the bottom diameter of the outer ring Rbo, the tip clearance is Ctip, and Rta = Rbo + 4 × (e + α) −2 ×. By adopting a variable displacement oil pump of e + 2 × Ctip, the radial size can be changed while the meshing state between the inner teeth of the outer ring and the outer teeth of the rotor chamber is further improved. it can.

  In the invention of claim 4, the variable capacity oil pump of the present invention is most easily designed by setting the number of teeth of the inner dentition of the outer ring or the outer dentition of the rotor chamber to 6 or 8. Can be. In addition, since the number of machining points can be relatively small, machining costs can be reduced.

(A) is a schematic diagram of the variable capacity oil pump in the first embodiment of the present invention, and (B) is an enlarged view of part (I) of (A). (A) is the schematic of the state which the outer rotor moved with the outer ring in 1st Embodiment of this invention, and the discharge amount changed. It is a characteristic view of the present invention. (A) is a schematic diagram of a variable capacity oil pump according to a second embodiment of the present invention, and (B) is an enlarged view of part (II) of (A). (A) is a schematic diagram of a variable capacity oil pump of the prior art, and (B) is an enlarged view of part (III) of (A).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The variable displacement oil pump of the present invention is an internal gear pump. The present invention mainly includes a pump housing A, an inner rotor 3, an outer rotor 4, and an outer ring 5 (see FIGS. 1, 2, and 4). 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. 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 is formed with a plurality of external teeth 31 (see FIG. 2). Further, a boss hole 32 for a drive shaft is formed at the central position in the diameter direction, and a drive shaft 33 is fixedly passed through the boss hole 32. The inner rotor 3 is rotated by the rotational drive of the drive shaft 33. To do.

  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.

  A plurality of cells (interdental spaces) S, S,... Are formed between 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.

  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 the operation of 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.

  The outer ring 5 is formed in a substantially annular shape, and is provided with operating means such as a lever (not shown) that is formed in a protruding shape outward in the diameter direction from a predetermined portion of the outer peripheral side surface 51. In addition, a holding portion 52 serving as a perfect circular through hole is formed on the inner side of the outer ring 5. The outer ring 5 is swing-operated in the rotor chamber 1 via the operating means (see FIG. 2).

  The holding portion 52 is formed as a circular inner peripheral wall surface, and the inner diameter of the holding portion 52 is slightly larger than the outer diameter of the outer rotor 4, so that the outer rotor 4 can rotate smoothly. It is comprised so that it may become.

  The rotation center of the outer ring 5 is located at the same position as the rotation center Pb of the outer rotor 4 inserted into the holding portion 52. The outer ring 5 is disposed in the rotor chamber 1, and the outer rotor 4 is disposed in the holding portion 52 to rotatably support the outer rotor 4 and to swing through the operating means.

  The outer ring 5 is built in the rotor chamber 1 of the pump housing A and is configured to be swingable within the rotor chamber 1. The rotor chamber 1 is slightly wider than the outer shape of the outer ring 5, and a space is provided for the outer ring 5 to swing.

  An outer tooth row 6 is formed on the inner peripheral side surface of the rotor chamber 1 (see FIGS. 1 and 4). An inner tooth row 7 is formed on the outer periphery (outer peripheral side surface 51) of the outer ring 5 (see FIGS. 1 and 4). When the outer ring 5 swings, the outer tooth row 6 and the inner tooth row 7 can accurately reciprocate the rotation center Pb of the outer ring 5 along the fan-shaped locus set by the eccentricity e. It serves as a guide.

  The outer tooth row 6 formed on the inner peripheral side surface of the rotor chamber 1 is composed of a plurality of outer tooth profile portions 61, 61,. The inner tooth row 7 formed on the outer peripheral side surface 51 of the outer ring 5 is composed of a smaller number of the inner teeth 71, 71,. The outer teeth 61, 61, ... and the inner teeth 71, 71, ... are formed at equal intervals. In addition, the outer tooth portions 61, 61, ... and the inner tooth portions 71, 71, ... may be formed at non-uniform intervals. Even in this case, the corresponding external tooth profile 61 and internal tooth profile 71 are determined in advance.

  The outer teeth 61, 61,... Of the outer teeth row 6 and the inner teeth 71, 71,... Of the inner teeth 7 are always meshed with each other with the outer teeth 61 being in relation to the inner teeth 71. It is the structure which moves while contacting while sliding. The outer tooth shape portion 61 and the inner tooth shape portion 71 have an arcuate line shape, and may be a single arcuate line or a plurality of different arcuate lines formed smoothly and continuously.

及び

上記式において「ｅ」は、偏心量である。「α」は、補正値である。 Next, the dimensions of the outer tooth row 6 and the inner tooth row 7 will be described. First, the dimensions of the tooth height Tha of the outer tooth profile portion 61 of the outer tooth row 6 and the tooth height Thb of the inner tooth shape portion 71 of the inner tooth row 7 are set as follows.

as well as

In the above formula, “e” is the amount of eccentricity. “Α” is a correction value.

  The correction value α is a numerical value for correcting the value of the eccentricity e. The correction value α is a positive number. Specifically, the correction value α is a small number of 1 or less, and is a small number such as 0.01 to 0.1, except for 0 (zero). Further, since the correction value α is (e + α) is the tooth height (tooth height), the larger α is, the larger the radial direction of the oil pump is. The smaller α is, the larger the oil pump diameter is. The size of the direction can be reduced.

Ｒboは、アウターリング５の内側歯列７の歯底円直径である。 Next, the tip circle diameter Rtb of the inner tooth row 7 of the outer ring 5 is as follows.

Rbo is the root diameter of the inner tooth row 7 of the outer ring 5.

Next, the tip circle diameter Rta of the outer tooth row 6 of the rotor chamber 1 is as follows.

  As described above, the tooth profile shapes of the inner tooth row 7 of the outer ring 5 and the outer tooth row 6 of the rotor chamber 1 are the root circle diameter Rbo of the outer ring 5, the eccentricity e, and the inner tooth row 7 of the outer ring 5. Can be determined by determining the correction value α of the number of teeth and the amount of eccentricity of the inner teeth 71 and the outer teeth 61 of the outer teeth 6 of the rotor chamber 1. The root diameter of the outer tooth row 6 is Rao.

  FIG. 1 shows a first embodiment of the present invention, where the number of inner tooth portions 71, 71,... Of the inner tooth row 7 of the outer ring 5 is six and the outer teeth of the rotor chamber 1 are In this example, the number of external tooth portions 61, 61,. In FIG. 1 (B), the tip circle diameter Rta of the outer tooth row 6 is (e + α), No. 1 on the uppermost side as viewed in FIG. It is shown that (e + α) is subtracted below, and the root circle diameter Rao is viewed from the pitch circle diameter Rap in FIG. 1 (A), with the uppermost (e + α) in FIG. 1 (A). It is shown that (e + α) is added to the lowermost side.

  FIG. 4 shows a second embodiment of the present invention, where the number of inner tooth portions 71, 71,... The number of external teeth 61, 61,. The outer ring 5 is moved by the operation means (not shown) while the rotation center Pb is moved, so that the position of the outer rotor is also displaced and the discharge amount is changed.

  FIG. 3 is a graph showing the characteristics of the present invention. In the condition where the above formula is satisfied, the inner rotor of the actual tip clearance (gap in the radial direction between the teeth and teeth) generated between the inner tooth row 7 of the outer ring 5 and the outer tooth row 6 of the rotor chamber 1. The change with respect to a rotation angle is shown. The characteristics of the prior art are also indicated by dotted lines in the graph.

  The graph of FIG. 3 is constant regardless of the angle when the tooth height = 2 × eccentricity as in the prior art, and smoothly rotates at any rotation angle. For this reason, the subject that the angle area | region which cannot rotate smoothly exists does not exist.

  On the other hand, when the height of the tooth height is changed with respect to the conventional height as in the present invention, the tip clearance between the inner tooth row 7 of the outer ring 5 and the outer tooth row 6 of the rotor chamber 1. Depending on the phase, there is an angle that does not rotate smoothly because it becomes extremely large. Therefore, in the present invention, the tooth profiles are only a part of contact range, and the tip clearance between the inner tooth row 7 of the outer ring 5 and the outer tooth row 6 of the rotor chamber 1 hardly changes with respect to the angle change, and the clearance. Can be rotated smoothly by using a portion having a relatively small angle range as a tooth profile.

A ... Pump housing, 1 ... Rotor chamber, 3 ... Inner rotor, 4 ... Outer rotor,
5 ... Outer ring, 6 ... Outer dentition, e ... Eccentricity, Tha ... Tooth length (outer dentition 6),
Pa ... rotation center (of the inner rotor 3),
Pb ... rotation center (outer rotor 4, outer ring 5),
Thb ... tooth height (inside tooth row 7), Rta ... tooth tip circle diameter (outside tooth row 6),
Rtb ... the diameter of the tip circle (of the inner dentition 7), Rbo ... the diameter of the root circle (of the outer ring 5),
Ctip: Tip clearance.

Claims (4)

An inner rotor, an outer rotor rotating with a predetermined eccentricity with respect to the rotation center of the inner rotor, and the rotation center of the outer rotor with respect to the rotation center of the inner rotor with the eccentricity as a radius. An outer ring to be moved, and a pump housing having a rotor chamber that houses the inner rotor, the outer rotor, and the outer ring,
The tooth height Tha of the outer dentition of the rotor chamber and the tooth height Thb of the inner dentition of the outer ring are the eccentricity e between the rotation center of the inner rotor and the center of the outer ring in the rotor chamber, By adding a positive correction value α,

as well as

A variable displacement oil pump characterized by In claim 1, when the tip circle diameter Rtb of the inner dentition of the outer ring is Rbo, the root circle diameter of the outer ring is Rbo.

A variable displacement oil pump characterized by The tip circle diameter Rta of the outer dentition of the rotor chamber according to claim 1,
If the diameter of the root circle of the outer ring is Rbo and the tip clearance is Ctip,

A variable displacement oil pump characterized by 2. The variable capacity oil pump according to claim 1, wherein the number of teeth of the inner teeth row of the outer ring and the outer teeth row of the rotor chamber is six or eight.

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