JP5194308B2 - Internal gear pump rotor - Google Patents

Description

  The present invention relates to a method for generating a tooth profile of an inner gear pump inner rotor in which an inner rotor and outer rotor having a single tooth difference are combined, an internal gear pump rotor using the inner rotor, and the rotor The present invention relates to the used internal gear pump. Specifically, the degree of freedom of the setting of the tooth height and the number of teeth is given, and the theoretical discharge amount of the pump can be increased and the pulsation can be suppressed.

  The internal gear pump is used as an oil pump for lubricating a car engine or an automatic transmission (AT). Among the rotors for pumps used in this internal gear type pump, there is a combination of an inner rotor and an outer rotor with one tooth difference, and in addition, a trochoid curve is used in that type of rotor. Some have created the tooth profile of the rotor, and some have created the tooth profile of the rotor with a cycloid curve.

  The tooth profile created using the trochoid curve is created using a basic circle E and a rolling circle F that rolls without sliding on the basic circle E, as shown in FIG. Specifically, the trochoid curve TC is drawn with a locus of one point on the radius away from the center of the rolling circle F by a distance e (= the amount of eccentricity between the center of the inner rotor and the outer rotor). The tooth profile of the inner rotor 2 is created by the envelope of the arc group of the locus circle G having a constant diameter centered on the trochoid curve (see Patent Document 1).

  In addition, the tooth profile of the cycloid curve is the trajectory of a point on the circumference of the foundation circle, the abduction circle that circumscribes the foundation circle without rolling on the foundation circle, and the foundation circle that is inscribed in the foundation circle. The tooth profile of the inner rotor is created by the locus of one point on the circumference of the inversion circle that rolls without slipping.

As for the tooth profile using the trochoid curve, the value of the basic circle E, the rolling circle F, the locus circle G, and the amount of eccentricity e is set to one for each tooth profile. In a pump having the tooth profile, the tooth height may be increased in order to increase the discharge amount. However, if the eccentricity e between the inner rotor and the outer rotor is increased for the purpose of increasing the tooth height, the tooth width is reduced. 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 becomes large, and it is difficult to meet the requirement of increasing the discharge amount without changing the outer diameter of the rotor.

  The same applies to an internal gear pump that employs a tooth profile having a cycloid curve. In this type of pump, the number of teeth of the rotor is determined by the diameter of the foundation circle and the diameter of the abduction circle and the inversion circle that rolls without sliding on the foundation circle and creates a tooth profile. Further, since the tooth height of the rotor is determined by the diameters of the abduction circle and the inversion circle, the discharge amount of the pump 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.

  In addition, the internal gear pump increases the number of discharges from the pump chamber (pumping chamber) during one rotation of the inner rotor as the number of teeth increases, so the pulsation of discharge pressure decreases. However, as described above, in the conventional internal gear type pump, when the number of teeth is increased while satisfying the discharge amount, the rotor size increases, so that the number of teeth 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). This tooth height can be changed arbitrarily by increasing the tooth height, thereby increasing the volume of the pump chamber formed between the teeth of the inner rotor and the outer rotor and increasing the discharge amount of the pump (patent) Reference 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 designing the tooth profile is increased. In particular, if the tooth tip of the inner rotor and the tooth profile of the root are created using a creation circle that moves with a change in diameter, the diameter change amount from the start point to the end point of the creation circle can be changed. Therefore, 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).

  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 increase the number of teeth and reduce the discharge pulsation of the pump (see Patent Document 2, paragraph 0026).

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

  Although the internal gear pump described in Patent Document 2 has received some appreciation, the number of teeth can be determined by the user when used for lubricating a car engine or for an automatic transmission (AT). In some cases, the outer diameter of the outer rotor may be determined, and it may not be possible to satisfy the requirements by satisfying the requirements such as suppressing pulsation as in the conventional case.

The present invention further increases the degree of freedom in designing the tooth profile with respect to the internal gear pump described in Patent Document 2, and also provides an inter-tooth gap between the inner rotor tooth surface and the outer rotor tooth surface (T ₁ to T _{1 in} FIG. 10). it is an object to T ₄ reference) greatly to be adapted to reduce the pulsations.

In order to solve the above-mentioned problem, as shown in FIGS. 2 to 5, the present invention provides an internal gear pump described in Patent Document 2, in which the center pa of the creation circles B and C, the movement start point Spa of the pb, Spb is positioned forward in the direction of movement of the creation circles B and C with respect to the straight line L ₁ from the center O _I of the reference circle A to the creation circle B and C that overlaps the reference circle A. .
In this way, the starting point tangent to the addendum 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, and the initial (addendum portion 2b the first part) becomes that sleep directed from the branch point J of the tooth bottom tooth tip T _T and the tooth bottom T _B, interdental gap increases. Increasing the interdental gap reduces pulsation and improves inhalation characteristics.
By the way, in the cycloid tooth profile and the tooth profile described in Patent Document 2, the center of the rolling circle (creation circle) is on the circumference of the basic circle (reference circle), and the starting point tangent of the tip curve or root curve is the foundation. It is on a straight line (L _{1 in} FIG. 2) connecting the circle and the tooth profile start point.

Specifically, the method for creating the tooth profile of the inner rotor for the internal gear pump according to the present invention combines the inner rotor 2 having n teeth and the outer rotor 3 having (n + 1) teeth, A method for creating a tooth profile of an inner rotor for an internal gear type pump that sucks and discharges fluid by a volume change accompanying rotation of a rotor of a pump chamber 4 formed between three teeth,
The following conditions (1) created circle B satisfies to (3), moves the C, the creation circle B which overlaps with the reference point J on the base circle A is an inner rotor center O _I concentrically between them, on C point j reference circle the locus curve drawn by the center O _I from the tooth tip apex T _T or tooth root apex leading to T _B straight line L _2, L tooth drawn symmetrically relative to ₃ addendum curve 2a, the tooth bottom of the A configuration in which at least one of the curves 2b is used 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 are the creation circles B, C with respect to the straight line L ₁ where the movement start points Spa, Spb of the creation circles B, C extend from the reference circle center O _I to the reference point J. there is located in the moving forward of the inner rotor center _{O I} from creation circle center pa, the distance of the reference circle diameter direction to the pb, moving start point Spa, end-of-travel Lpa from Spb, to Lpb, the addendum curve 2a For example, the distance is increased or changed in the case of the root curve 2b.
Depending on the condition, the distance of the tooth tip curve is increased or the distance of the root curve is decreased. Depending on the condition, the generating circle center movement curves AC ₁ and AC ₂ are On the side, the slope curve gradually moves outward (upward to the right in FIG. 2) with respect to the direction of movement of the creation circle, and on the root side, it gradually moves inward with respect to the direction of movement of the creation circle. An inclined curve (upward to the left in FIG. 2) is formed, and accordingly, the arcuate locus (tooth profile curve) drawn by the point j is inclined with respect to the moving direction of the generating circle (toward the outside on the tooth tip side). If you are at the bottom of the tooth, go inward).

(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.

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.

A straight line connecting the reference point J on the reference circle A and the inner rotor center O _I is L _1, and the movement start point Spa at the center of the tooth tip creation circle B and the movement start point Spb at the center of the tooth creation circle C are straight lines. The movement end points Lpa and Lpb are on the straight lines L ₂ and L ₃ , at positions away from L ₁ by angles θ _T0 and θ _B0 to the left and right. Therefore, addendum vertex _{T T} is set on the straight line _{L 2} of positions rotated angle θ _T + θ _T0 from the straight line _{L 1,} the tooth bottom vertex _{T B} has an angle θ _B + θ _B0 rotation from the straight line _{L 1} It is set on the straight line L ₃ positions. These angles θ _T , angle θ _T0 , angle θ _B , and angle θ _BO are set in consideration of the number of teeth, the ratio of the tooth tip portion, and the installation region of the tooth bottom portion.

The internal gear type pump inner rotor manufactured by the above-described internal gear type pump inner rotor tooth profile creation method has the above-described conditions according to the tooth profile creation method.
Further, an internal gear type pump rotor can be configured by combining the inner rotor having the tooth profile and the following outer rotor (see FIG. 9).
The tooth profile of the outer rotor 3 is determined by the following process.
The center O _I of the inner rotor 2 revolves once on a circle S having a diameter (2e + t) centered on the center O ₀ of the outer rotor 3.
Meanwhile, the inner rotor 2 rotates 1 / n times.
An envelope of a tooth profile curve group formed by the revolution and rotation of the inner rotor 2 is drawn.
The envelope determined in this way is used as a tooth profile.
here,
e: Eccentric amount of the center of the inner rotor 2 and outer rotor 3 t: Tip clearance n: Number of teeth of the inner rotor

Note that the tip clearance here is defined as follows.
First, located in the inner rotor 2 is the inner rotor center O _I origin, further established the inner rotor 2 in a state in which the addendum vertex T _T of the inner rotor 2 is positioned in the negative region on the Y-axis passing through the origin To do.
Next, the outer rotor center O ₀ is at one point on the Y-axis that is away from the origin by the amount of eccentricity e, and the tooth tip vertex of the outer rotor 3 abuts the tooth tip vertex of the inner rotor in a negative region on the Y-axis. The outer rotor 3 is installed in a state where
Then, the outer rotor center O ₀ is moved on the Y axis in a direction away from the inner rotor center O _I until the tooth profile of the inner rotor 2 and the tooth profile of the outer rotor 3 come into contact with each other. The clearance generated between the tip of the tip of the inner rotor 2 on the Y axis and the tip of the tip of the outer rotor 3 on the Y axis at the tip clearance measurement position thus created is defined as a tip clearance t. .

  Further, the internal gear type pump rotor of the present invention described above can be housed in a rotor chamber provided in the pump housing to constitute an internal gear type pump.

When the tooth creation circle B and the tooth creation circle C are circles whose diameter changes during movement, the diameters Bd _max and Cd _{max at} the movement start point of the creation circle are set in consideration of the target tooth height. The 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.

In the present invention, by adopting the above configuration, the starting point tangent of the tooth tip curve or the bottom curve is inclined toward the tooth tip or the tooth bottom side, and the initial tooth shape is the same as the straight line L _{1 at the} branch point J. without a direction, it becomes to tilt toward the tooth tip T _T or tooth bottom T _B, interdental gap increases. Increasing the interdental gap reduces pulsation and improves inhalation characteristics. Therefore, the inclination angle θs toward the tooth tip T _T or tooth bottom T _B at its initial (creation circle B, the center pa and C, the position of the pb) by arbitrarily selecting the while meeting the needs of the user, An internal gear pump in which a required discharge amount and pulsation are suppressed can be obtained.

(A) End view showing an example of the pump rotor of the present invention, (b) End view of the rotor chamber in a state where the pump chamber of the rotor is confined. 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 tooth creation circle with a constant diameter Illustration of how to create the tooth profile of the inner rotor using the creation circle with diameter change Image diagram showing the movement of the center of the tooth creation circle with diameter change (A) End view showing another example of the pump rotor of the present invention (in which the tooth tip of the inner rotor is created using a tooth tip creation circle having a constant diameter), (b) the rotor pump chamber of the rotor is confined. End view (A) An end view showing still another example of the pump rotor of the present invention (in which the tooth tip of the inner rotor is created using a tooth tip creation circle having a constant diameter), (b) End view of the trapped state An end view showing an example of a pump rotor in which the tooth tip of the inner rotor is created using a creation circle with a diameter change The figure which shows the formation method of the tooth profile of an outer rotor 1 is an end view showing the internal gear pump employing the pump rotor of FIG. 1 with the housing cover removed. (A) is an end view showing the tooth profile of the pump rotor of Invention 1 used in the embodiment, and (b) is an end view showing a state where the pump chamber of the rotor is confined. (A) is an end view showing the tooth profile of the pump rotor of invention 2 used in the embodiment, and (b) is an end view showing a state where the pump chamber of the rotor is confined. (A) is an end view showing the tooth profile of the pump rotor of Comparative Example 1, and (b) is an end view showing a state where the pump chamber of the rotor is confined. (A) is an end view showing the tooth profile of the pump rotor of Comparative Example 2, and (b) is an end view showing a state where the pump chamber of the rotor is confined. Illustration of tooth profile creation method using trochoid curve

  Embodiments of a pump rotor according to the present invention will be described below with reference to FIGS. The pump rotor 1 shown in FIG. 1 is configured by combining an inner rotor 2 having n teeth (n = 6 in the figure) and an outer rotor 3 having (n + 1) teeth. 2a is a tooth tip (tooth tip curve) of the inner rotor 2, and 2b is a tooth bottom (tooth root curve) of the inner rotor 2. The inner rotor 2 has a shaft hole 2c at the center.

The inner rotor 2 has a tooth profile that is concentric with the inner rotor, and a tooth tip generating circle B and / or a point j on the circumference passing through a reference point J that is the intersection of the reference circle A and the Y axis. It is created using the root creation circle C. A specific example of the tooth profile is a combination of a tooth tip 2a and a tooth bottom 2b created based on the following conditions. The reference circle A is a circle having a radius from the inner rotor center O _I to the boundary point between the tooth tip and the tooth bottom, and the point j starts to move from this circle.

In FIG. 2, the diameter of the tooth tip creation circle B is Bd,
A straight line connecting the inner rotor center O _I and the reference point J is L ₁ ,
The straight line connecting the inner rotor center _{O I} and the tooth tip apex _{T T L} 2,
A moving start point Spa of the center of the addendum creating circle B, the inner rotor center _{O I} and creating a circular movement angle ∠Spa said made at three points of the tip apex _{T T,} O I, the _{T T θ T,} creating a circle the moving start point Spa of the center is positioned created circular movement direction ahead of the straight line L _1, the moving start point Spa and the inner rotor center O _I and the angle made by the three points of reference points J ∠Spa, O I, a _J theta _T0, the addendum curve 2a of the starting point tangent lines _{L 1} of the angle θs (> 0).
Center pa of the addendum creation circle B is the moving start point Spa, end-of-travel Lpa toward the straight line L ₂ side (which is on the straight line L ₂₎ moves in a range of angle theta _T up. At this time, the rotational 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 a constant angular velocity, and the point j on the creation circle changes from the reference point J to the tooth tip vertex T. _{T (This} addendum circle and the straight line L ₂ having a diameter D _T that is set in advance is in a position intersecting) to reach. During this time, 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 to FIG. 3 at the same time).

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.

Such an addendum curve 2a drawn in the inverted with respect to the straight line L ₂ (around the straight line L ₂ is symmetrically) by, addendum curve 2a of the inner rotor 2 is completed.

The root curve (the root 2b) can be drawn in the same manner. 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. _B (a moving start point Spb of the center pb addendum creation circle C, the inner rotor center _{O I} and the dedendum creating circular movement angle made at three points of the vertex _{T B ∠Spb, O I, T} B) in the range of Move.
The mobile tooth bottom vertex a point j of the circumference of the dedendum creation circle C is set on the straight line L ₃ from the reference point J by T _{B (which} is the addendum circle and a straight line L having a diameter D _B which is set in advance Half of the tooth profile of the tooth bottom 2b of the inner rotor 2 is drawn by the trajectory that has been moved until it reaches ₃ ). At this time, similarly, the moving start point Spb of creating circle center pb is positioned created circular movement direction ahead of the straight line L _1, the angle made by the three points of the moving start point Spb and the inner rotor center O _I and the reference point J ∠ _{Spb, O} I, a J theta _B0, and tooth bottom curve 2b of the starting point tangent lines _{L 1} of the angle θs (> 0).

  In the tooth profile creation by the above method, the tooth creation circle B and the tooth creation circle C move from the movement start points Spa and Spb to the movement end points Lpa and Lpb while keeping their diameters Bd and Cd constant. A half of the tooth profile of the tooth tip 2a or the tooth bottom 2b of the inner rotor is drawn by the locus of the point j. However, the tooth profile creation method is not limited to these. The tooth tip creation circle B and the tooth bottom creation circle C move from the movement start points Spa and Spb to the movement end points Lpa and Lpb while changing their diameters. The object of the present invention can also be achieved by a method of drawing half of the tooth profile of the tooth bottom 2b.

FIG. 4 and FIG. 5 show the principle of tooth profile creation when a creation circle with a change in diameter is used.
In FIG.
The diameter at the movement start point of the tooth creation circle B is defined as Bd _max ,
A straight line connecting the inner rotor center O _I and the reference point J is L ₁ ,
The straight line connecting the inner rotor center _{O I} and the tooth tip apex _{T T L} 2,
Center and the moving start point Spa of the addendum creating circle B, the angle made at three points of the inner rotor center _{O I} and the tooth tip apex _{T T ∠Spa,} O _I, the _{T T θ T,} the movement of the created circle center the start point Spa is located creation circular movement direction ahead of the straight line _{L 1,} the moving start point Spa and the inner rotor center _{O I} and the angle made by the three points of reference points J _{∠Spa, O I,} a J and theta _T0.
Center pa of the addendum creation circle B is the moving end point Lpa toward the moving start point Spa to the straight line L ₂ side (which is on the straight line L ₂₎ rotation angle θ to _T moved to. 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.

The tooth tip creation circle B rotates at a constant angular velocity while reducing its diameter while the center pa of the tooth tip creation circle B reaches the movement end point Lpa from the movement start point Spa. Then, the point j on the creation circle B rotates to rotate the tooth tip vertex T _T set on the straight line L ₂ (this is the position where the tooth tip circle of the preset diameter D _T intersects the straight line L _2. To reach). During this time, 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. Addendum creation circle B has a diameter in the position reached in the tooth tip apex T _T is changed to Bd _min. According to this method, it is possible to increase the radius of curvature of the tooth tip as compared with a tooth profile drawn using a creation circle having a constant diameter. In addition, a tooth profile in which the difference between the gap near the tip clearance and the tip clearance is reduced can be obtained.

Incidentally, the straight line L ₂ and the tooth profile of the half-teeth depicting the moving direction of the range of directions and angles theta _T by and the method described above for the same rotation of the addendum creation circle B is inverted with respect to the straight line L ₂ Creating a tooth profile having a symmetrical shape centering on the same as the case of creating a tooth profile using a creation circle having a constant diameter.

The root curve (tooth base tooth profile) 2b can be similarly drawn. The root creation circle C having a diameter Cd at the movement start point Spb is rotated at a constant angular velocity in a direction opposite to the direction in which the tooth tip creation circle B rotates, and from the movement start point Spb to the movement end point Lpb while reducing the diameter. To move. The dedendum creation circle C of a tooth bottom vertex a point j is set on the straight line L ₃ from the reference point J circumference T _{B (which} is the root circle and the straight line L ₃ of the diameter D _B which is set in advance A half of the tooth profile of the root of the inner rotor is drawn based on the trajectory that the point j has moved until it reaches (at the intersecting position). Be drawn symmetrically the tooth profile of the half with respect to the straight line L ₃ may one tooth of the tooth bottom shape. At this time, creating the circle center pb moving start point Spb was positioned created circular movement direction ahead of the straight line L ₁ of the moving start point Spb and the inner rotor center O _I and at three points of the reference point J made angular ∠Spb, O _{Let I} and J be θ _B0 .

The number of teeth n, the diameter D _{T of the} tip circle, the diameter D _B of the root circle, the creation circle movement angle θ _T (∠ Spa, O _I , T _T ) from the movement start point Spa to L ₂ , and the movement start point Spb to L creation circular movement angle of up to _{3 θ B (∠Spb, O I} , T B), the diameter of the moving start point of the tip creating a circle B and dedendum creating circle C _{Bd max, Cd max,} diameter at end-of-travel _{(Bd min} = Bd−ΔBd), (Cd _min = Cd−ΔCd), and a curve in which the centers pa and pb of the tooth tip creation circle B and the tooth bottom creation circle C move are set in advance, so that the tooth profile can be created by the above method.

The centers pa and pb of the tooth tip creation circle B and the tooth root creation circle C have curves AC ₁ and AC _{2 in which the} rate of change ΔR ′ of the movement amount ΔR is 0 at the movement end points Lpa and Lpb of the creation circle centers pa and pb. It is preferable to move up. In this case, the tip of the tooth is not sharp, and there is an effect of improving discharge performance (increase in discharge amount) by stabilizing the clearance near the tip clearance, preventing noise during pump operation, and improving the durability of the rotor. .

It is also preferable that the curves AC ₁ and AC ₂ are, for example, curves using a sine function (the movement amount ΔR is expressed by the following equation).
ΔR = R × sin ((π / 2) × (m / S))
Here, S: number of steps, m = 0 → S
In this way, the rate of change ΔR ′ of the movement amount ΔR at m = S becomes 0, and a smooth curve can be drawn. At this time, the circumferential movement amount Δθ of the creation circle centers pa and pb is
Δθ = θ _T / S or θ _B / S
It is.

As the curves AC ₁ and AC ₂ , a cosine curve, a higher-order curve, an arc curve, an elliptic curve, or a curve obtained by combining these curves and a straight line having a certain slope is used in addition to the sine curve that is preferable. can do.

When the creation circle centers pa and pb move from the movement start points Spa and Spb to the movement end points Lpa and Lpb while the creation circles B and C reduce the diameter, the diameter change rate Δr ′ of the creation circles B and C It is preferably 0 at the movement end points Lpa and Lpb at the center of the circle. Thereby, it becomes easy to increase the curvature radius of the tooth tip 2a or the tooth bottom 2b. For this reason, similarly to ΔR, the amount of change Δr of the creation circle diameters Bd and Cd that has changed with the movement of the creation circles B and C satisfies, for example, the following expression using a sine function.
Δr = r × sin ((π / 2) × (m / S))

The outer rotor 3 is used having one more tooth than the inner rotor 2 (the number of teeth in FIG. 1 is 7). The tooth profile of the outer rotor 3 is created by the following steps as shown in FIG. First, the center O _I of the inner rotor 2 revolves one revolution on a circle S having a diameter around the center Oo of the outer rotor 3 (2e + t). Meanwhile, the inner rotor 2 rotates 1 / n times. An envelope of a tooth profile curve group formed by the revolution and rotation of the inner rotor 2 is drawn. The envelope determined in this way is used as a tooth profile.
here,
e: Eccentricity between the center of the inner rotor and the center of the outer rotor t: Tip clearance n: Number of teeth of the inner rotor

  In the inner rotor 2 in which the curve characterizing the present invention explained in FIG. 2, FIG. 3, or FIG. 4 and FIG. 5 (hereinafter referred to as the tooth profile curve of the present invention) is applied to the tooth tip 2a, the root shape is The tooth tip creation circle C may be used in the same manner as the tooth tip 2a, or a tooth profile created using a known trochoid curve or a cycloid curve tooth profile may be employed. Similarly, in the inner rotor 2 in which the tooth profile curve of the present invention is applied to the tooth bottom 2b, the tooth tip shape may be a tooth profile created using a trochoid curve or a cycloid curve tooth profile.

  The tooth profile obtained by combining the tooth profile curve and the cycloid curve according to the present invention has a smooth meshing with the outer rotor, which is a feature of the cycloid curve, and can increase the tooth height. Thereby, the request | requirement of increasing discharge amount is satisfy | filled.

  In the tooth profile to which the tooth profile curve of the present invention is applied, the tooth tip height and the tooth root depth of the inner rotor are determined by the value of the radial movement distance R of the tooth tip generating circle B and the tooth generating circle C. In the tooth profile to which the tooth profile curve of the present invention is applied, the magnitude of the movement distance R can be freely set. Therefore, even when either the tooth tip 2a or the tooth bottom 2b is a tooth profile of a trochoid curve or a cycloid curve, The degree of freedom in setting the length is secured.

  The inner rotor 2 and the outer rotor 3 described above are combined in an eccentric arrangement to constitute the internal gear type pump rotor 1. Then, the internal gear pump rotor 1 is housed in a rotor chamber 6 of a pump housing 5 having a suction port 7 and a discharge port 8, as shown in FIG. In the internal gear pump 9, a drive shaft (not shown) is inserted into the shaft hole 2 c of the inner rotor 2 to engage the inner rotor 2 and the drive shaft, and a driving force is transmitted from the drive shaft to transmit the inner rotor. Rotate 2 At this time, the outer rotor 3 is driven and rotated, and the volume of the pump chamber 4 formed between the two rotors is increased or decreased to suck and discharge fluid such as oil.

As described above, when creating the tooth tip 2a of the tooth profile, on the curve AC _{1 in} which the distance from the inner rotor center O _I to the center pa of the creation circle B increases from the movement start point Spa to the movement end point Lpa. When creating the tooth bottom 2b of the tooth profile, the distance from the inner rotor center O _I to the center pb of the creation circle C is on the curve AC ₂ where the distance decreases from the movement start point Spb toward the movement end point Lpb. The centers pa and pb of the creation circles B and C move. Meanwhile, the creation circles B and C rotate. Then, at least one tooth profile of the tooth tip 2a or the tooth bottom 2b of the inner rotor 2 is created by the locus of one point j on the circumference of the creation circles B and C. By doing so, the tooth height of the inner rotor 2 can be made larger than the tooth height of the conventional internal gear type pump adopting the tooth profile of the trochoid curve or the cycloid curve. Therefore, the volume of the pump chamber 4 formed between the teeth of the inner rotor 2 and the outer rotor 3 becomes larger than that of the conventional product, and the pump discharge amount increases.

  Further, by doing so, the number of teeth of the inner rotor can be made larger than the number of teeth of the conventional internal gear type pump adopting the tooth profile of the trochoid curve or the tooth profile of the cycloid curve. Therefore, the number of pump chambers 4 formed between the teeth of the inner rotor 2 and the outer rotor 3 is larger than that of the conventional product, and the pump discharge amount is increased.

Furthermore, the tangent angle (90 ° -θs) at the start point of the tooth tip curve 2a or the tooth bottom curve 2b is 90 degrees or less, and the initial tooth shape (from the branch point J between the tooth tip portion and the tooth bottom portion to the tooth tip T _T , the first portion) toward the tooth bottom T _B is in the branch point J, without a straight line L ₁ and the same direction, it becomes to tilt toward the tooth tip T _T or tooth bottom T _B, the interdental gap It becomes larger (see T _{1 to} T _{4 in} FIG. 10). Increasing the interdental gap reduces pulsation and improves inhalation characteristics. Therefore, the inclination angle θs toward the tooth tip T _T or tooth bottom T _B at its initial (creation circle B, the center pa and C, the position of the pb) by arbitrarily selecting the while meeting the needs of the user, An internal gear pump in which a required discharge amount and pulsation are suppressed can be obtained.

Figure 8 is the condition addendum diameter of the inner rotor 2 (diameter of the addendum circle) is equal, while reducing the diameter of the tip creating a circle B, from the inner rotor center O _I to the center of the tip creating a circle B 4 is a tooth profile drawn by the method of FIG. 4 with the amount of change in distance increased by an amount corresponding to the reduction amount of the diameter of the tooth creation circle B. Compared with the tooth profile of the inner rotor of FIG. 1 created using the tooth creation circle B having a constant diameter, the tooth profile has a larger radius of curvature of the tooth tip and can reduce the gap between the outer rotor tooth tip and the vicinity. I can do it. Therefore, the volumetric efficiency of the pump is improved.

  6 and 7 show another embodiment of the pump rotor 1 of the present invention. The internal gear type pump rotor of FIG. 6 is a design in which the present invention is applied to both the tooth tip (tooth tip curve) 2a and the tooth bottom (tooth root curve) 2b of the inner rotor 2. Further, in the internal gear type pump rotor of FIG. 7, the present invention is applied to the tooth tip curve 2a of the inner rotor 2, and the tooth bottom 2b is constituted by a cycloid curve. The internal gear type pump rotor shown in FIGS. 6 and 7 uses a generating circle having a constant diameter for generating the tooth profile curve of the invention. As can be seen from these embodiments, the internal gear type pump rotor of the present invention has a degree of freedom in tooth profile design even when a generating circle having a constant diameter is used.

  Test results of performance evaluation of the pump rotor of the present invention are described below. An inner rotor 2 having 6 teeth and an outer rotor 3 having 7 teeth, each of which is formed of an iron-based sintered alloy, are manufactured. did.

The combinations of the curves of the tooth tip 2a and the tooth bottom 2b of the inner rotor 2 used in the test are as follows.
Comparative Example 1 (see FIG. 13)
Tooth curve: cycloid curve Tooth curve: cycloid curve Comparative Example 2 (see FIG. 14)
Tooth tip curve: Invention tooth profile curve described in Patent Document 2 (θs = 0)
Tooth root curve: Invention tooth profile curve described in Patent Document 2 (θs = 0)
Invention 1 (see FIG. 11)
Tooth tip curve: Invention tooth profile curve (θs> 0)
Tooth root curve: Invention tooth profile curve (θs> 0)
Invention 2 (see FIG. 12)
Tooth tip curve: Invention tooth profile curve (θs> 0)
Tooth root curve: Invention tooth profile curve (θs> 0)

Common specifications are
Outer rotor outer diameter: φ60mm
Inner rotor inner diameter: φ15mm
Rotor thickness: 15mm
Each tooth profile was created by the following method. At this time, each outer rotor 3 created a tooth profile by using the inner rotor 2 of the combination partner and the envelope of the tooth profile curve group obtained by the method of FIG.

[Comparative Example 1]
The cycloid curve of the tooth tip of Comparative Example 1 was created by rolling an abduction circle having a diameter of 3.25 mm without slipping on a basic circle having a diameter of φ39 mm. The cycloid curve of the tooth bottom was created by rolling an inward circle having a diameter of 3.25 mm on a basic circle having a diameter of 39 mm without sliding.
The diameter of the tip of the inner rotor and the outer rotor (the diameter of the tip circle), the root diameter (the diameter of the root circle), and the eccentricity e of the created inner rotor and outer rotor are as follows.
Inner rotor tooth tip diameter: φ45.5mm
Inner rotor tooth root diameter: φ32.5mm
Outer rotor tooth tip diameter: φ39.1 mm
Outer rotor tooth root diameter: φ52.1mm
Eccentricity e: 3.25 mm
θ _T0 : 0 °
θ _B0 : 0 °
θs: 0 °

[Comparative Example 2]
The tooth profile curves of the tip and root of Comparative Example 2 were created by the method of the invention described in Patent Document 2 using creation circles B and C having a constant diameter on the basic circle A. The specifications at this time are as follows.
Diameter Ad of basic circle A: φ37.75mm
Creation circle B diameter Bd: φ3.15mm
Diameter Cd of creation circle C: φ3.15mm
Radial distance of creation circle B R: 0.5mm
Radial movement amount ΔR of the creation circle B: 0.5 mm × sin ((π / 2) × (m / s))
Radial movement distance R of the creation circle C: 0.2mm
Radial movement amount ΔR of the creation circle B: 0.2 mm × sin ((π / 2) × (m / s))
Number of steps S: 30
θ _T0 : 0 °
θ _B0 : 0 °
θs: 0 °
Inner rotor tooth tip diameter: φ45.0mm
Inner rotor tooth root diameter: φ31.0mm
Outer rotor tooth tip diameter: φ51.9mm
Outer rotor tooth bottom diameter: φ38.3mm
Eccentricity e: 3.4 mm

[Invention 1]
The invention tooth profile curve of the tooth tip of Invention 1 was created by the method of FIG. 2 using a reference circle A and a creation circle B having a constant diameter. The specifications at this time are as follows.
Diameter Ad of reference circle A: φ40.0mm
Creation circle B diameter Bd: φ2.3mm
Radial distance of creation circle B R: 1.1mm
Movement amount ΔR: 1.1 × sin ((π / 2) × (m / S))
Number of steps S: 30
θ _T0 : 80 °
θs: 21 °
The invention tooth profile curve of the tooth bottom was created by the method of FIG. 2 using the reference circle A described in FIG. 2 and the creation circle C having a constant diameter. The specifications at this time are as follows.
Diameter Ad of reference circle A: φ40.0mm
Diameter Cd of creation circle C: φ4.3mm
Radial movement distance R of the creation circle C: 2.0mm
Movement amount ΔR: 2.0 × sin ((π / 2) × (m / S))
Number of steps S: 30
θ _B0 : 85 °
θs: 21 °
The tip diameter and root diameter of the created inner rotor and outer rotor, and the amount of eccentricity e are as follows. These numerical values are also the same in the following invention 2.
Inner rotor tooth tip diameter: φ45.1mm
Inner rotor tooth root diameter: φ31.5mm
Outer rotor tooth tip diameter: φ38.3mm
Outer rotor tooth bottom diameter: φ51.9mm
Eccentricity e: 3.4 mm

[Invention 2]
The invention tooth profile curve of the tooth tip of Invention 2 was created by the method of FIG. 4 using a reference circle A and a creation circle B that causes a diameter change during movement. The specifications at this time are as follows.
Diameter Ad of reference circle A: φ41.4mm
Diameter Bd _{max at} the movement start point of the tooth tip creation circle B: φ2.4 mm
Diameter Bd _{min at the} end point of movement: φ0.6mm
Change amount of diameter of tooth creation circle: Δr = 1.8 × sin ((π / 2) × (m / S))
Radial movement distance R of the center of the tooth creation circle B: 0.7 mm
Movement amount: ΔR = 0.7 × sin ((π / 2) × (m / S))
Number of steps S: 30
θ _T0 : 48 °
θs: 19 °
The invention tooth profile curve of the tooth bottom of Invention 2 was created by the method of FIG. 4 using a reference circle A and a tooth bottom creation circle C that causes a diameter change during movement. The specifications at this time are as follows.
Diameter of reference circle A: 41.4mm
Diameter Cd _{max at} the movement start point of the root creation circle C: φ4.5 mm,
Diameter Cd _{min at the} movement end point: φ4.0 mm
Change amount of diameter of tooth creation circle: Δr = 0.5 × sin ((π / 2) × (m / S))
Radial movement distance R of the root creation circle C: 2.9 mm
Movement amount ΔR: 2.9 × sin ((π / 2) × (m / S))
Number of steps S: 30
θ _B0 : 85 °
θs: 19 °

An internal gear pump was constructed by incorporating an internal gear pump rotor in which the inner rotor 2 and the outer rotor 3 having the above specifications were combined into a pump housing. And the discharge amount of each pump on the following test conditions was compared. The results are shown in Table 1 below.
"Test conditions"
Oil type: ATF
Oil temperature: 80 degrees
Discharge pressure: 2.5MPa
Rotation speed: 3000rpm

  From this test result, the inventive products 1 and 2 that incline the starting point tangent of the tooth tip curve or the tooth bottom curve, as compared with Comparative Examples 1 and 2, the pump discharge amount increases and the discharge pulsation decreases, It can be seen that the objects of the invention are achieved.

1 rotor for pump 2 inner rotor 2a tooth tip (tooth tip curve)
2b tooth bottom (bottom curve)
2c Shaft hole 3 Outer rotor 4 Pump chamber 5 Pump housing 6 Rotor chamber 7 Suction port 8 Discharge port 9 Internal gear type pump A Reference circle Ad Reference circle A diameter B Tooth tip creation circle Bd Tooth tip creation circle B diameter Spa Movement start point Lpa of the tooth tip creation circle B Movement end point Bd _{max of the} tooth tip creation circle B Diameter Bd _{min at} the movement start point of the tooth tip creation circle B _Min Diameter ΔBd at the movement end point of the tooth tip creation circle B Diameter of the tooth creation circle B Change amount C Tooth root creation circle Cd Diameter Spb of the root creation circle C Movement start point Lpb of the root creation circle C Movement end point Cd of the root creation circle C _max Diameter Cd _{min at} the movement start point of the tooth creation circle C Diameter ΔCd at the end point of movement of the circle C Amount of change in diameter of the root creation circle C ₁ A curve AC where the center of the tooth creation circle B moves ₂ A curve J where the center of the tooth creation circle C moves J On the reference circle A Reference point j Linear L ₂ inner rotor center O _I and the tooth tip apex T _T connecting the tooth bottom vertex L ₁ inner rotor center O _I and the reference point J of the tip apex T _B the inner rotor of the 1-point T _T inner rotor on Naruen movement angle of the straight line theta _T created circle B connecting straight line _{L 3} inner rotor center _{O I} and the tooth bottom vertex _{T B} connecting _{(∠Spa, O I, T T} )
θ _B movement angle of creation circle C (∠ Spb, O _I , T _B )
θ _T0 , θ _B0 The center movement start point deviation angle of the creation circles B and C θs The angle R between the start point tangent of the tooth tip curve or the root curve and the straight line L ₁ The radial movement distance from the creation start point of the creation circle to the movement end point ΔR Amount of radial movement pa from the starting point of the creation circle pa, pb Distance from the creation circle center R ₀ , R ₁ inner rotor center O _I to the center of the tooth tip creation circle B from r ₀ , r ₁ inner rotor center O _I teeth O _I eccentricity t tip clearance n inner rotor tooth bottom creating circle C diameter e the inner rotor center to a distance D _T of the inner rotor diameter D _B inner rotor of the addendum circle of the tooth bottom circle of the outer rotor circle E basic circle F Utateen TC trochoid curve G circular path having a diameter of the inner rotor center _{O O} outer rotor center S 2e + t

Claims (5)

The inner rotor (2) with n teeth and the outer rotor (3) with (n + 1) teeth are combined to rotate the rotor of the pump chamber (4) formed between the teeth of both rotors (2, 3). A method for creating a tooth profile of an inner rotor for an internal gear type pump that sucks and discharges fluid by a volume change accompanying,
The creation circle (B, C) is moved while satisfying the following conditions (1) to (3), and the reference point (J) on the reference circle (A) that is concentric with the inner rotor center (O _I ) A trajectory curve drawn by the point (j) on the overlapping creation circle (B, C) is a straight line (L ₂ ,) extending from the center of the reference circle (O _I ) to the tip of the tip (T _T ) or the tip of the root (T _B ). A tooth profile creation method for an inner rotor for an internal gear pump that is drawn symmetrically with respect to L ₃ ) and is at least one of a tooth tip curve (2a) and a tooth bottom curve (2b).
-Moving conditions (1) to (3) of the creation circle (B, C)-
(1) Creation of the creation circle (B, C) so that the point (j) on the creation circle (B, C) overlaps the reference point (J) on the reference circle (A) From the movement start point (Spa, Spb) where the circle center (pa, pb) is positioned, the point (j) on the generating circle (B, C) is the tip of the tooth tip (T _T ) or the root of the tooth (T _B ). The creation circle center movement curve (AC ₁ , ACb) to the movement end point (Lpa, Lpb) where the creation circle center (pa, pb) is positioned when the creation circle (B, C) is arranged so as to be located at ₂ ) The creation circle center (pa, pb) moves on the surface, and the creation circle (B, C) rotates at a constant angular velocity in the same direction as the movement direction of the creation circle.
(2) The creation circle center movement curve (AC ₁ , AC ₂ ) indicates that the creation start point (Spa, Spb) of the creation circle (B, C) is from the reference circle center (O _I ) to the reference point (J). Reference circle diameter direction from the inner rotor center (O _I ) to the creation circle center (pa, pb), which is located forward of the creation circle (B, C) in the movement direction with respect to the straight line (L ₁ ) leading to In the tooth tip curve (2a), the distance is increased or changed from the movement start point (Spa, Spb) to the movement end point (Lpa, Lpb), or the root curve (2b) The distance is reduced.
(3) The tip of the tooth tip (T _T ) or the bottom of the tooth tip (T _B ) is the movement start point (Spa) of the creation circle (B) and the center of the reference circle (O _I ) in the radial direction of the reference circle (A). Is longer than the distance (R ₀ ) plus the radius of the creation circle (B) at the movement start point, away from the center of the reference circle (O _I ), or the movement start point (Spb) of the creation circle (C) ) And the reference circle center (O _I ), the distance (r ₀ ) exceeds the length obtained by subtracting the radius of the creation circle (C) at the start of movement and approaches the reference circle center (O _I ). The inner rotor (2) with n teeth and the outer rotor (3) with (n + 1) teeth are combined to rotate the rotor of the pump chamber (4) formed between the teeth of both rotors (2, 3). A rotor for an internal gear type pump that sucks and discharges fluid by a volume change accompanying,
The reference point on the reference circle (A) that is concentric with the center of the inner rotor (O _I ) during which the creation circle (B, C) having a constant diameter moves while satisfying the following conditions (1) to (3) A straight line (L ₂ , L) from the center of the reference circle (O _I ) to the tip of the tip (T _T ) or the tip of the root (T _B ) of the locus curve drawn by the point (j) on the generating circle overlapping with (J) ₃ ) A rotor for an internal gear type pump including the inner rotor (2) drawn symmetrically with respect to the tooth profile curve (2a) and at least one of the root curve (2b).
-Moving conditions (1) to (3) of the creation circle (B, C)-
(1) When the creation circle (B, C) is arranged so that the point (j) on the creation circle overlaps the reference point (J) on the reference circle (A), the creation circle center (pa, From the movement start point (Spa, Spb) at which pb) is positioned, the creation circle ( _B ) such that the point (j) on the creation circle is located at the top of the tooth tip (T _T ) or the bottom of the root (T _B ). , C) on the creation circle center movement curve (AC ₁ , AC ₂ ) up to the movement end point (Lpa, Lpb) where the creation circle center (pa, pb) is positioned when the creation circle center (pa, pb) is positioned. , Pb) move, and the generating circle (B, C) rotates at a constant angular velocity in the same direction as the moving direction of the circle.
(2) The creation circle center movement curve (AC ₁ , AC ₂ ) is such that the creation start point (Spa, Spb) of the creation circle (B, C) is from the center (O _I ) of the reference circle (A). It is located in front of the generating circle (B, C) in the moving direction with respect to the straight line (L ₁ ) leading to the point (J), and the moving end point (Lpa, Lpb) is the tooth tip vertex (T _T ) or the tooth root vertex. _{(T B)} and be on the inner rotor center _{(O I)} connecting the straight line _(L 2, L _3), the reference circle diameter of the from the inner rotor center _{(O I)} to creation circle center (pa, pb) The distance in the direction is changed from the movement start point (Spa, Spb) to the movement end point (Lpa, Lpb) by increasing the distance in the case of the tooth tip curve or by changing the distance in the case of the root curve. Decrease change.
(3) The rotation rotation angle (θ) of the generating circle is 180 ° + the following generating circle movement angle (θ _T ) in the tooth tip curve, and 180 ° −the following in the tooth bottom curve. The creation circle movement angle (θ _B ), and the creation circle center (pa, pb) on the creation circle center movement curve (AC ₁ , AC ₂ ) is the diameter of the reference circle (A) from the movement start point (Spa, Spb). The amount of movement (ΔR) moved in the direction satisfies the following formula, and the tip apex (T _T ) or the root apex (T _B ) is the creation circle (B) in the radial direction of the reference circle (A). Away from the reference circle center (O _I ) beyond the distance (R ₀ ) between the movement start point (Spa) and the reference circle center (O _I ) plus the radius of the creation circle (B) at the start of movement It is, or, distance of the moving start point (Spb) and the reference circle center of creation circle _{(C) (O I) (} r 0) to the moving start point when the wound Are close to the reference circle center (O _I) exceeds the radius length obtained by subtracting the circle (C).
ΔR = R × sin ((π / 2) × (m / S))
Here, the distance from R :( inner rotor center _{(O I)} to the tooth tip side moving end point of creation circle center _{(pa) (Lpa) (R} 1)) - Creation circle center from (inner rotor center _{(O I)} (Pa) distance to the tooth tip side movement start point (Spa) (R ₀ )) or (distance from the inner rotor center (O _I ) to the tooth root side movement start point (Spb) of the generating circle center (pb) ( r ₀ )) − (distance (r ₁ ) from the inner rotor center (O _I ) to the root end side movement end point (Lpb) of the generation circle center (pb)), the generation circle movement angle (θ _T ) in the tooth tip curve : The angle (∠Spa, O _I , Lpa) created by the three points of the tooth tip side movement start point (Spa), the inner rotor center (O _I ), and the movement end point (Lpa), the creation circle movement angle in the root curve (Θ _B ): The root side movement start point (Spb) And the angle (∠ Spb, O _I , Lpb) formed by three points of the inner rotor center (O _I ) and the movement end point (Lpb), S: number of steps, m = 0 → S, and the number of steps S is , The number of the created circle movement angle (θ _T ) or the same angle (θ _B ) divided at equal intervals. The rotor for an internal gear pump according to claim 2, wherein the generating circle (B, C) satisfies the following diameter change condition (4).
(4) A variation amount Δr = r × sin ((π / 2) × (m / s)) of the creation circle diameter that has changed with the movement of the creation circle (B, C).
Here, r: (creation circle diameter at the movement start point (Bd _max , Cd _max )) − (creation circle diameter at the movement end point (Bd _min , Cd _min )). An internal gear type pump rotor configured by combining the inner rotor (2) according to claim 2 or 3 and an outer rotor,
The center (O _I ) of the inner rotor (2) revolves once on a circle (S) having a diameter (2e + t) centered on the center (O _O ) of the outer rotor (3),
During that time, the inner rotor (2) rotates 1 / n times,
Draw the envelope of the tooth profile curve group formed by the revolution and rotation of this inner rotor,
An internal gear pump rotor including the outer rotor having the envelope determined in this way as a tooth profile.
here,
e: Eccentricity between the center of the inner rotor and the center of the outer rotor t: Tip clearance n: Number of teeth of the inner rotor   An internal gear pump constructed by housing the pump rotor (1) according to any one of claims 2 to 4 in a rotor chamber (6) provided in a pump housing (5).

Images