JP2012137024A - Rotor for internal gear type pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a tip clearance t in a theoretical eccentric position of an inner rotor 2 and an outer rotor 3 from becoming large in a half-tooth position (a state of Fig.(b)) of rotating the inner rotor 2 by a half angle of one tooth from a top position (a state of Fig.(a)) with respect to the top position.SOLUTION: This rotor for an internal gear type pump is provided by eccentrically e combining the inner rotor 2 having a tooth number of n and the outer rotor 3 having a tooth number of (n+1). The inner rotor 2 is higher in a tooth height than a cycloid tooth shape in the same in the small diameter Ls and the tooth number n, and is set as an eccentric quantity e<(a large diameter (Lo) of the inner rotor 2-a small diameter (Ls) of the inner rotor 2)/4. Thus, when the eccentric quantity e is reduced, for example, reduced by 0.1 mm than conventional (Lo-Ls)/4, the tip clearance t of both positions (Fig.(a) and (b)) becomes the same (0.030 mm) so as to be understandable from the Fig.(a) and (b), and reduction in volumetric efficiency of a pump room 4 is not caused.

Description

  The present invention relates to an internal gear type pump rotor in which an inner rotor and an outer rotor having a difference in the number of teeth are eccentrically combined, and an internal gear type pump using the rotor.

The internal gear pump is used as an oil pump for lubricating a car engine or an automatic transmission (AT). As shown in FIG. 1 showing an embodiment of the present invention, this internal gear type pump normally has an inner rotor 2 having n teeth (natural number) and an outer rotor 3 having teeth number (n + 1) eccentrically. Thus, the rotor 1 is combined and the rotor 1 is housed in the rotor chamber 6 of the pump housing 5 having the suction port 7 and the discharge port 8.
At this time, the tooth profile of the outer rotor 3 is, for example, after determining the tooth profile of the inner rotor 2, as shown in FIG. 5, the diameter of the inner rotor 2 the center O _I is about the center Oo of the outer rotor 3 Determined by revolving one revolution on the circle S of (2e + t), during which the inner rotor 2 rotates 1 / n times, and drawing an envelope of a group of tooth profile curves formed by repeating the revolution and rotation of the inner rotor 2 It is set as the said envelope.
here,
e: amount of eccentricity of the center Oo of the center _{O I} and the outer rotor 3 of the inner rotor 2 t: tip clearance n: number of teeth of the inner rotor 2

Among the rotors for pumps 1 employed in the internal gear type pump 9, there are those that have created the tooth profile of the rotor 1 using a trochoid curve (see Patent Document 1) and those that have created the tooth profile of the rotor with a cycloid curve. is there.
As for the tooth profile using the trochoid curve, the basic circle, the rolling circle, the locus circle, and the amount of eccentricity are set to one for each tooth profile. In order to increase the discharge amount, the pump having the tooth profile needs only to increase the tooth height (see H in FIG. 3a). However, the eccentric amount e of the inner rotor 2 and the outer rotor 3 is intended to increase the tooth height. If is increased, the tooth width becomes too narrow, or the tooth profile design itself becomes impossible. Therefore, the amount of eccentricity e is restricted, and therefore the tooth height is also limited, making it difficult to meet the demand for increasing the discharge rate.
Moreover, if the number of teeth is increased even with the same tooth height, the discharge amount can be increased. However, when the number of teeth is increased, the diameter of the rotor 1 increases, and it is difficult to meet the demand for increasing the discharge amount without changing the outer diameter of the rotor 1.

  Similarly, the tooth profile using the cycloid curve is created by rolling without sliding on the diameter of the basic circle and the basic circle, and therefore the number of teeth of the rotor 1 is determined by the diameter of the abduction circle and the inversion circle. Further, since the tooth height of the rotor 1 is determined by the diameters of the abduction circle and the inversion circle, the pump discharge amount depends on the diameters of the basic circle and the rotation circle. Therefore, the degree of freedom regarding the setting of the tooth height and the number of teeth is low, and it is difficult to meet the demand for increasing the discharge amount of the pump.

  Furthermore, in the internal gear type pump, since the number of discharges from the pump chamber (pumping chamber) 4 during one rotation of the inner rotor 2 increases as the number of teeth increases, the pulsation of the discharge pressure decreases. However, as described above, the conventional internal gear type pump having a tooth profile of a trochoid curve or a cycloid curve increases the number of teeth because the rotor size increases when the number of teeth is increased while satisfying the discharge amount. Is also limited.

  Under such circumstances, the inventors of the present application made the creation circle corresponding to the abduction circle and the inversion circle move and rotate under specific conditions, thereby generating the radial direction of the creation circle of the tooth tip and the root. The tooth profile formation method which can change a tooth height arbitrarily by changing a movement amount was considered (patent document 2). The fact that the tooth height can be changed arbitrarily is that the volume of the pump chamber 4 formed between the teeth of the inner rotor 2 and the outer rotor 3 is increased by increasing the tooth height, thereby increasing the discharge amount of the pump. (See Patent Document 2, paragraphs 0022 to 0023).

  In addition, since the degree of freedom can be set in various conditions such as the diameter of the creation circle and the amount of radial movement of the creation circle, the degree of freedom in the tooth profile design is also increased. In particular, when the tooth tip of the inner rotor 2 and the tooth profile of the tooth bottom are created using a creation circle that moves with a change in diameter, the amount of change in diameter between the creation start point and the movement end point of the creation circle is changed. Thus, since the tooth profile can be changed, the degree of freedom in designing the tooth profile is further increased (see Patent Document 2, paragraph 0024, etc.).

  Furthermore, this idea does not have the concept of a basic circle, and the number of teeth can be determined regardless of the basic circle and the amount of eccentricity, so there is a degree of freedom in setting the number of teeth. For this reason, it is also possible to reduce the noise caused by the pulsation by increasing the number of teeth to reduce the discharge pulsation of the pump (see paragraph 0026 of Patent Document 2).

JP-A-61-201892 WO 2010/016473 A1

By the way, when the tooth height H is increased, as can be understood from FIGS. 4A and 4B described later, the tip clearance t at the theoretical eccentric position of the inner rotor 2 and the outer rotor 3 is the top position (the same figure). With respect to the state of (a), for example, t = 0.030 mm, the position of the half tooth from which the inner rotor 2 is rotated 22.5 degrees (the state of FIG. ) May increase. When the tip clearance t becomes large, it causes a decrease in volumetric efficiency of the pump chamber 4.
This invention makes it a subject to suppress that the chip clearance t in the position of the half tooth becomes large.

In order to solve the above-described problems, the present invention is conventionally, for example, in the case of a cycloid tooth profile, the large diameter L _I o -the same small diameter L _I s of the inner rotor 2 is twice the tooth height H (FIG. 4 (a ) Is not a cycloid tooth profile, but refer to its L _I o etc.), and the eccentricity e is ½ of its tooth height H. For this reason, e = H / 2 = (inner rotor large diameter L _Io−the same small diameter L _I s) / 4, and this is followed in other trochoidal tooth forms and the creation method described in Patent Document 2. Thus, the amount of eccentricity e was set to (inner rotor large diameter L _I o −the same small diameter L _I s) / 4.

However, when the amount of eccentricity e is made smaller than (inner rotor large diameter L _I o −the same small diameter L _I s) / 4 (about 0.1 mm smaller), from FIGS. 3A and 3B described later. As can be understood, the tip clearance t at the theoretical eccentric position of the inner rotor 2 and the outer rotor 3 is the top position (the state shown in FIG. 5A, for example, t = 0.030 mm) and the half-tooth position (the same figure). It became the same in the state of (b), t = 0.030 mm), and it was confirmed that the tip clearance t (0.045 mm) at the position of the conventional half tooth was smaller.
That is, it was discovered that the tip clearance t at the half-tooth position does not increase if the amount of eccentricity e is made smaller than (inner rotor large diameter L _I o −the same small diameter L _I s) / 4.

Based on this discovery, the present invention is an internal gear type pump rotor in which the inner rotor 2 having n teeth and the outer rotor 3 having (n + 1) teeth are combined eccentrically. The tooth height is higher than that of a cycloid tooth having the same small diameter and the same number of teeth n, and the eccentricity e <(large diameter L _I o of the inner rotor 2−small diameter L _I s of the inner rotor 2) / 4 The configuration was adopted.
Here, the condition that “the inner rotor 2 has a small diameter and a tooth height higher than that of a cycloid tooth profile having the same number of teeth n” is, for example, the condition that the inner rotor 2 has a small diameter and the same number of teeth n. In the case of the tooth profile of the above condition according to the tooth profile creation method described in Patent Document 2 in which the tooth height is made higher than that of the tooth profile, the eccentric amount e = (inner rotor large diameter L _I o −the same small diameter L _I s) / 4. This is because the problem of the tip clearance t shown in FIGS. 4A and 4B has occurred.

The inner rotor 2 has a small diameter and a tooth height higher than that of a cycloid tooth having the same number of teeth n, and the eccentricity e <(large diameter L _I o of the inner rotor 2−small diameter L of the inner rotor 2 _{As the} tooth profile that can be set to Is) / 4, it is preferable that the degree of freedom of the tooth profile design described in Patent Document 2 is arbitrary, such as an arbitrary tooth height and tooth profile. For this reason, in the rotor 1 for the internal gear type pump having the above-described configuration, it is preferable to employ the following configuration shown in FIGS. 2a and 2b.
The creation circles B and C that satisfy the following conditions (1) to (3) are moved, and the creation circles B and C overlap with the reference point J on the reference circle A that is concentric with the inner rotor center O _I during the movement. The locus curve drawn by the upper point j is drawn symmetrically with respect to the straight lines L ₂ and L ₃ extending from the reference circle center O _I to the tooth tip vertex T _T or the tooth root vertex T _B , and the tooth shape tooth tip curve 2a, tooth A configuration in which at least one of the bottom curves 2b is adopted.

-Moving conditions for creation circles B and C (1)-(3)-
(1) Moving start point where the creation circle centers pa and pb are positioned when the creation circles B and C are arranged so that the point j on the creation circles B and C overlaps the reference point J on the reference circle A Spa, from Spb, creation circle B, creating a circle B so as to be positioned at a point j Gaha destination vertex _{T T} or tooth root apex _{T B} on C, its creation circle center pa when placing the C, and pb positioning The creation circle centers pa and pb move on the creation circle center movement curves AC ₁ and AC ₂ up to the movement end points Lpa and Lpb, and the creation circles B and C are constant in the same direction as the creation circle movement direction. Rotates at angular velocity.
With this condition (1), the centers pa and pb of the creation circles B and C move on the creation circle center movement curves AC ₁ and AC ₂ , so that the point j on the creation circle draws a tooth profile, and When the generating circles B and C rotate at a constant angular velocity, the point j draws an arc-shaped locus.

(2) The creation circle center movement curves AC ₁ , AC ₂ indicate the distance in the reference radial direction from the inner rotor center O _I to the creation circle center pa, pb, from the movement start point Spa, Spb to the movement end point Lpa, Up to Lpb, the distance is increased in the tooth tip curve 2a, or the distance is decreased in the tooth bottom curve 2b.
Depending on this condition, the distance of the tooth tip curve 2a is increased or the distance of the root curve 2b is decreased. Depending on the condition, the generating circle center movement curves AC ₁ and AC ₂ are On the tooth tip side, an inclination curve (upward to the right in FIG. 2a) gradually moves outward with respect to the moving direction of the generating circle, and on the tooth bottom side, gradually moves inward with respect to the moving direction of the generating circle. A moving slope curve (upward to the left in FIG. 2a), and accordingly, the arc-shaped locus (tooth profile curve) drawn by the point j is inclined with respect to the direction of movement of the creation circle (outside on the tooth tip side) Toward the inside, if it is at the bottom of the tooth).

(3) the addendum vertex T _T or tooth root apex T _B is in the radial direction of the reference circle A, creating a circular moving start point Spa and the reference circle center O _I of the distance R ₀ creation circle at moving start point to the B and B of being away radially from the reference circle center O _I beyond the length obtained by adding, or the radius of the creation circle C at moving start point to the distance r ₀ of the moving starting point Spb and the reference circle center O _I of the created circle C It is close to the reference circle center O _I beyond the length obtained by subtracting.
Under this condition, the tooth height is higher than the generating circle diameter, and the tooth height is higher than the cycloidal curve tooth profile of the rolling circle rolling on the basic circle.

The creation circles B and C are a circle in which the center of the creation circle moves from the movement start point to the movement end point while keeping the diameters Bd and Cd constant, and the center of the creation circle moves while reducing the diameters Bd and Cd. There are two possible circles that move from the starting point to the moving end point. These creation circles can be selected appropriately in consideration of the required performance of the pump. If the diameters Bd and Cd of the creation circles B and C are moved while being reduced, the degree of freedom in designing the tooth profile increases.
In addition, the movement start points Spa and Spb at the center of the creation circles B and C are on the straight line L ₁ from the reference circle center O _I to the reference point J, or the creation circles B and C move forward in the movement direction with respect to the straight line L ₁ . Or can be located in When is positioned in front, starting tangent of the tip curve 2a or tooth bottom curve 2b is inclined to the tooth tip T _T or tooth bottom T _B side, the tooth profile (addendum-dedendum curve) 2a, 2b of the initial (addendum The first portion from the branch point J between the tooth portion and the tooth bottom portion toward the tooth tip T _T and the tooth bottom T _B ), and the initial interdental spacing increases. Increasing the interdental spacing reduces pulsation and improves inhalation characteristics.
Creating circles B, C of the moving end point Lpa, Lpb is preferably located on the straight line _L 2, _{L 3,} the straight line _L 2, _{L 3} created circle against B, be located towards the moving direction before and after C You can also.

In this internal gear type pump rotor, on the curves AC ₁ and AC ₂ where the change rate ΔR ′ of the distance between the inner rotor center O _I and the generating circle centers pa and pb is 0 at the movement end points Lpa and Lpb. It is preferable that the creation circle centers pa and pb move.

The curves AC ₁ and AC ₂ are preferably curves using a sine function. For example, the amount of movement ΔR in which the creation circle centers pa and pb move on the creation circle center movement curves AC ₁ and AC ₂ from the movement start points Spa and Spb in the radial direction of the reference circle A is a curve that satisfies the following expression.
ΔR = R × sin ((π / 2) × (m / S))
Here, R: (distance from the inner rotor center O _I to the moving end point Lpa of the generating circle center pa) − (distance from the inner rotor center O _I to the moving starting point Spa of the generating circle center pa), or (inner rotor center The distance from O _I to the movement start point Spb of the creation circle center pb) − (the distance from the inner rotor center O _I to the movement end point Lpb of the creation circle center pb), and hereinafter, “the radial movement distance of the creation circle” Or simply called “movement distance”. S: Number of steps, m = 0 → S, and the number of steps S represents the creation circle movement angle θ _T or θ _{B formed} by the movement start points Spa, Spb, the inner rotor center O _I and the movement end points Lpa, Lpb. The number divided into equal intervals.

The tooth tip vertex T _T is set on a straight line L ₂ at a position rotated by a constant angle θ _T from the straight line L ₁ connecting the reference point J on the reference circle A and the center of the inner rotor, and the tooth bottom vertex T _B is a straight line. is set from the L ₁ on predetermined angle theta _B rotated position of the straight line L _3. The fixed angles θ _T and θ _B are set in consideration of the number of teeth, the tip portion, and the ratio of the installation region of the bottom portion.

When the tooth tip creation circle B and the tooth bottom creation circle C are circles whose diameters change during movement, the diameters Bd _max and Cd _{max at} the movement start point of these creation circles are the target values as in the above-mentioned Patent Document 2. It is set in consideration of tooth height. When the diameter change amounts between the starting point and the moving end point of both creation circles are ΔBd and ΔCd, respectively, the tip height and root depth for determining the tooth height are obtained by the following equations.
Tooth height = R + (Bd / 2) + {(Bd−ΔBd) / 2}
Tooth depth = R + (Cd / 2) + {(Cd−ΔCd) / 2}

In these two expressions, R, Bd, ΔBd, Cd, and ΔCd are all numerical values that can be arbitrarily set. Then, several tooth profile models in which these values are variously changed in consideration of the change rate ΔR ′ of the movement amount ΔR are prepared, and R, Bd, ΔBd, Appropriate values of Cd and ΔCd can be found.
As for the diameters of the creation circles B and C, the diameters at the movement end points Lpa and Lpb are suitably 0.2 times or more and 1 time or less than the diameters at the movement start points Spa and Spb.

The tooth profile of the outer rotor in the internal gear type pump rotor having the above-described configuration can be created by a conventionally known means. For example, the center O _I of the inner rotor 2 shown in FIG. center O _O revolves one revolution on a circle S having a diameter (2e + t) centered at, and rotating the inner rotor 2 is (1 / n) times during which tooth profile formed by the rotation and revolution of the inner rotor 2 A group envelope can be drawn, and a tooth profile drawn on the same or outside of the envelope can be adopted.
Of course, such a pump rotor can be housed in a rotor chamber provided in the pump housing to form an internal gear pump, as in the conventional case.

  In the present invention, by adopting the above configuration, it is possible to suppress an increase in the tip clearance t at the position of the half-tooth, and therefore, the possibility of causing a decrease in volumetric efficiency of the pump chamber 4 is reduced.

The end view which shows the state which removed the cover of the housing of one Embodiment of the internal gear type pump of this invention Illustration of how to create the tooth profile of the inner rotor using a creation circle with a constant diameter Image diagram showing the moving state of the center of the creation circle It is an effect explanatory view of the embodiment, (a) is a position where tip clearance t is a top, and (b) is a position of the same half tooth. It is one action explanatory drawing of a prior art example, (a) is the position where the tip clearance t is a top, (b) is the action explanatory drawing of the same half tooth position same embodiment. The figure which shows one formation method of the tooth profile of an outer rotor

  FIG. 1 to FIG. 3 show an embodiment of the present invention. This embodiment is an inner rotor 2 having 8 teeth each formed of an iron-based sintered alloy by the tooth profile creation method described in Patent Document 2. And the outer rotor 3 having 9 teeth is combined, and the rotors 2 and 3 are combined to form an internal gear type oil pump rotor 1. The rotor 1 is a rotor of a pump housing 5 having a suction port 7 and a discharge port 8. The internal gear pump 9 is configured by being housed in the chamber 6.

  That is, as shown in FIGS. 2a and 2b, the inner rotor 2 has a tooth shape with a reference circle A that is concentric with the inner rotor, and a reference point in which a point j on the circumference is the intersection of the reference circle A and the Y axis. Creation is performed using a creation circle B and / or a root creation circle C passing through J. The tooth profile is a combination of a tooth tip and a tooth bottom created based on the following conditions, and the reference circle A is a circle having a radius from the center of the inner rotor to the boundary point between the tooth tip and the tooth bottom. The point j starts moving from above.

In FIG. 2a, the diameter of the tooth creation circle B is Bd,
A straight line connecting the inner rotor center O _I and the reference point J is L ₁ ,
A straight line connecting the center _{O I} and the tooth tip apex _{T T} of the inner rotor _L 2,
Angle ∠SpaO _I T _T (rotation angle from straight line L ₁ to L ₂ ) formed by three points of the movement start point Spa of the center of the tooth tip creation circle B, the inner rotor center O _I and the tooth tip vertex T _T Is _θT .
The center pa of the tooth tip creation circle B is the movement start point Spa (the center position of the tooth tip creation circle B at the position where the point j overlaps the reference point J. In FIG. 2a, the movement start point Spa is a straight line L _1. from the overlying), the moving end point Lpa (this toward the straight line L ₂ side is moved in a range of angle theta _T until on the straight line L _2). At this time, the angular velocity in the circumferential direction of the center pa of the tooth tip creation circle B is constant.
During this time, the center pa of the tooth tip creation circle B moves a distance R in the radial direction of the reference circle A.
While the center pa of the tooth tip creation circle B reaches the movement end point Lpa from the movement start point Spa, the tooth tip creation circle B rotates at an angle θ, and the point j on the creation circle changes from the reference point J to the tooth tip vertex T _T. To reach. During this time, a half of the tooth profile of the tooth tip 2a of the inner rotor is drawn by the locus of movement of the point j (refer also to FIG. 2b).

In this case, the direction of rotation of the addendum creation circle B, the moving direction of the angle theta _T are the same. That is, if the direction of rotation is clockwise, the direction of movement of the tooth creation circle B is also clockwise.

The tooth profile curve of the inner rotor is completed by reversing the tooth profile curve drawn in this way with respect to the straight line L ₂ (making the shape symmetrical about the straight line L ₂ ).

The root curve can be similarly drawn. While rotating the root creation circle C having a diameter Cd at a constant angular velocity in the direction opposite to the direction in which the tooth creation circle B rotates, the center pb of the root creation circle C is moved from the movement start point Spb toward the movement end point Lpb by an angle θ. Move within the range of _B. In this case, the tooth profile of the tooth bottom of the inner rotor by the moving trajectory until a point j of the circumference of the dedendum creation circle C has reached the tooth bottom vertex T _B which is set on the straight line L ₃ from the reference point J Half of is drawn. The root curve of the inner rotor is completed by reversing the root curve drawn in this manner with respect to the straight line L ₃ (symmetrical with respect to the straight line L ₃ ).

The tooth profile of the inner rotor 2 having 8 teeth according to the tooth profile creation example and the comparative example is produced with the following specifications, and the tooth profile of the outer rotor 3 is the center O _{I of the} inner rotor 2 shown in FIG. the upper circle S revolve one revolution of diameter around the center O _O of the outer rotor 3 (2e + t), and rotating the inner rotor 2 is (1 / n) times during the formation by rotation and revolution of the inner rotor 2 An envelope curve of the group of tooth profile curves was drawn and consisted of this envelope curve.

“Common Specifications”,
Outer rotor tooth root diameter (large diameter: Loo): φ51.94mm
Outer rotor tooth tip diameter (small diameter: Los): φ38.34 mm
Inner rotor tooth tip diameter (large diameter: L _I o): φ45.08 mm
θ _T : 11.25 °
θ _B : 11.25 °
Number of steps S: 30

"Example"
Inner rotor tooth root diameter (small diameter: L _I s): φ31.04 mm
Diameter Ad of reference circle A: φ35.50mm
Creation circle B diameter Bd: φ2.22mm
Radial movement distance R of the creation circle B: 2.58mm
Tooth tip movement amount ΔR: 2.58 × sin (π / 2 × m / S)
Creation circle C diameter Cd: φ2.2mm
Eccentricity e: 3.40 mm = ((45.08-31.04) /4-0.11) mm

"Comparative example"
Inner rotor tooth root diameter (small diameter: L _I s): φ31.48 mm
Diameter Ad of reference circle A: φ36.00mm
Creation circle B diameter Bd: φ2.25mm
Radial movement distance R of the creation circle B: 2.30mm
Tooth tip movement amount ΔR: 2.30 × sin (π / 2 × m / S)
Diameter Cd of creation circle C: φ2.25mm
Eccentricity e: 3.4 mm = ((45.08-31.48) / 4) mm

FIG. 3 shows a rotor in which the inner rotor 2 and the outer rotor 3 of the embodiment are meshed with each other, and FIG. 4 shows a rotor in which the inner rotor 2 and the outer rotor 3 of the comparative example are meshed with each other. 2 and the tip rotor t at the theoretical eccentric position of the outer rotor 3 is the top position, and (b) is the half-tooth position.
From FIG. 3 and FIG. 4, in the example, the tip clearance t is the same as “0.030 mm” in the states (a) and (b), whereas the comparative example is (a) and (b). In the state, the tip clearance t was 0.030 mm at the top position, but increased by 0.045 mm and 0.015 mm at the half-tooth position.
From this, the internal gear pump 9 incorporating the rotor 1 of the embodiment shown in FIG. 3 has a volumetric efficiency of the pump chamber 4 as compared to the internal gear pump incorporating the conventional rotor shown in FIG. It can be understood that it is excellent.

In the above embodiment, the tip creation circle B and the root creation circle C move from the movement start points Spa, Spb to the movement end points Lpa, Lpb while keeping their own diameters Bd, Cd constant, and the points in between Although the half of the tooth profile of the tooth tip 2a of the inner rotor 2 is drawn by the locus of j, the tooth profile creation method is not limited to these. For example, the tooth tip creation circle B and the tooth bottom creation circle C described in Patent Document 2 move from the movement start points Spa, Spb to the movement end points Lpa, Lpb while changing their diameters, and the trajectory in which the point j moves between them. It is also possible to adopt a method of drawing half of the tooth shape of the inner rotor tooth tip and the tooth bottom.
In addition, the movement start points Spa and Spb of the creation circles B and C may be positioned forward of the creation circles B and C in the movement direction with respect to the straight line L ₁ from the reference circle center O ₁ to the reference point J. .
Furthermore, a tooth profile creating method described in Japanese Patent Application No. 2009-163702 “by combining ellipses” may be employed. That is, for example, in an internal gear type pump rotor configured by combining an inner rotor and an outer rotor with a single tooth difference in an eccentric arrangement, a plurality of ellipses are in contact with each other or partially adjacent to each other. It is also possible to adopt a method in which a part of the curves of each ellipse are continuously connected in combination so as to overlap, and the tooth profile of the inner rotor is created by the continuously connected curves.
The tooth profile of the outer rotor 3 is not limited to the envelope of the tooth profile curve group formed by the revolution and rotation of the inner rotor 2 described above. The minimum tooth profile line of the outer rotor 3 for allowing the inner rotor 2 and the outer rotor 3 to rotate without interference is the envelope, and the outer rotor 3 can be formed as a tooth profile drawn outside the envelope. If it exists, the tooth profile by any means may be used.

DESCRIPTION OF SYMBOLS 1 Pump rotor 2 Inner rotor 3 Outer rotor 4 Pump chamber 5 Pump housing 6 Rotor chamber 7 Suction port 8 Discharge port 9 Internal gear type pump e Eccentric amount of inner rotor and outer rotor t Tip clearance n Number of teeth of inner rotor _I inner rotor center _{O O} outer rotor center circle with a diameter of S 2e + t _L I o inner rotor large-diameter _L I s inner rotor diameter

Claims (3)

In the internal gear type pump rotor in which the inner rotor (2) having n teeth and the outer rotor (3) having (n + 1) teeth are eccentrically combined,
The inner rotor (2) whose diameter (L I _s), be one tooth height number of teeth (n) is compared to the same cycloid tooth (H) is high, the eccentricity (e) <(inner rotor large diameter (2) _(L I o) - diameter _(L I s)) / 4 and to internal gear rotor pump, characterized in that the inner rotor (2). The outer rotor (3), revolves around _{(O I)} is one round circle (S) on a diameter centered on the center _{(O O)} of the outer rotor (3) (2e + t) of the inner rotor (2) In the meantime, the inner rotor (2) rotates (1 / n) times, and the envelope of the tooth profile curve group formed by the revolution and rotation of the inner rotor (2) is drawn, and is the same as or outside this envelope The internal gear type pump rotor according to claim 1, wherein the rotor has an indented shape drawn on the internal gear.   An internal gear pump configured by housing the pump rotor (1) according to claim 1 or 2 in a rotor chamber (6) provided in a pump housing (5).

Images