JP2008297999A - Internal gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear pump provided with an inner rotor and an outer rotor having trochoid gear teeth, and capable of reducing vibration caused by pulsation generated in the feed-out of fluid. <P>SOLUTION: The internal gear pump comprises a rotor chamber 61 having a suction port 62 and a delivery port 63, and also having a round inner circumference wall surface 612, a clearance groove 7 formed along the circumference direction of the inner circumference wall surface 612 without communicating with the delivery port 63, the inner rotor 2, the outer rotor 1 rotating while forming a cell S together with the inner rotor 2, a pin holding concave part 4 formed at any part of tooth bottom 112 of the outer rotor 1, and a pin member 3 held in the pin holding concave part 4 and always projecting out of the surface of the tooth bottom 112 and embedded in the pin holding concave part 4 by the tooth tip of the inner rotor 2. A communication hole communicating with the clearance groove 7 is formed at the pin holding concave part 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal gear pump that includes an inner rotor and an outer rotor having a trochoidal tooth profile and that can reduce vibrations caused by pulsations that occur during fluid delivery.

An internal gear pump is widely used as an oil pump for lubrication mounted on an automobile engine or the like. As the internal gear pump, a trochoid pump having an inner rotor and an outer rotor having a trochoidal tooth profile is often used. Such an internal gear pump has a structure in which a volume of oil corresponding to one cell is discharged in sequence as the inner rotor and the outer rotor rotate. When viewed in a very short time, since intermittent discharge is performed, discharge pulsation and vibration caused thereby are problematic. Patent Document 1 listed below is an example of an internal gear pump that does not cause such discharge pulsation.
JP 2000-291565 A

  In general, an internal gear pump such as a trochoid pump is configured so that an outer rotor and an inner rotor are appropriately meshed to rotate while forming an interdental space (cell), and the rotation is performed smoothly. Therefore, a very small gap (chip clearance) is provided between the inner teeth of the outer rotor and the outer teeth of the inner rotor. In Patent Document 1, in order to prevent oil from leaking from an appropriate cell to an adjacent cell, a seal member is attached to the tooth tip of the outer rotor, and the seal member is pressed against the tooth surface of the inner rotor.

  With the above configuration, there is a possibility that variations in the discharge pulsation may be suppressed, but since the oil does not move between cells when the cells are sealed, oil for the same cell volume is discharged at the same interval. The structural features of the internal gear pump that are made more pronounced. That is, although the variation in the discharge pulsation may be reduced, a phenomenon occurs in which the peak of discharge pulsation (regular pulsation) increases. By sending such regular pulsations of a specific frequency from the pump, the pump and peripheral devices are likely to resonate. When such resonance occurs, there is a problem that a vibration larger than the vibration due to the discharge pulsation is generated, which adversely affects peripheral devices. An object (technical problem) of the present invention is to reduce such a pulsation peak and prevent vibration.

  According to a first aspect of the present invention, a rotor chamber having a suction port and a discharge port and having a circular inner peripheral wall surface is formed along a circumferential direction of the inner peripheral wall surface and is not in communication with the discharge port. A clearance groove, an inner rotor, an outer rotor that rotates while forming a cell together with the inner rotor, a pin storage recess formed in any tooth bottom of the outer rotor, and the pin storage recess It consists of a pin member that always protrudes from the surface of the tooth bottom portion and is buried in the pin housing recess by the tooth tip portion of the inner rotor, and a communication portion that communicates with the escape groove is formed in the pin housing recess The above-described problems have been solved by using the internal gear pump.

  According to a second aspect of the present invention, the above-described problem is solved by using the internal gear pump in which the pin member is mounted on any of the plurality of tooth bottom portions of the outer rotor in the above-described configuration. According to a third aspect of the present invention, in the above-described configuration, the pin member is an internal gear pump in which an elastic member is mounted between the pin housing recess and the pin member. .

  According to a fourth aspect of the present invention, in the above-described configuration, the plurality of pin members are internal gear pumps having different sizes of protruding volumes from the tooth bottom portion, thereby solving the above-described problem. According to a fifth aspect of the present invention, the above-described problem is solved by employing an internal gear pump in which the pin member is formed in a cylindrical shape in the above-described configuration. The invention of claim 6 is the internal gear pump in which the tip shape of the pin member is formed in a substantially spherical shape in the above-described configuration, thereby solving the above problem.

  According to the first aspect of the present invention, the tooth bottom portion of either the outer rotor or the inner rotor is normally protruded from the surface of the tooth bottom portion and buried in the tooth bottom portion by the tooth tip portion meshing with the tooth bottom portion. As a result, the volume of the cell is reduced by the volume of the protruding portion of the pin member from the opening of the storage portion. Therefore, the amount of oil stored in the cell formed by the tooth bottom portion provided with the pin member is smaller than that of the cell formed by the tooth bottom portion not provided with the pin member.

  Therefore, when the cell reaches the start end of the discharge port, the amount of oil discharged is reduced, and thus the amount of protrusion is not always constant, and can be irregular, A pulsation peak due to discharge can be reduced, and vibration and noise can be prevented. Further, the pin member is structured to be buried in the tooth bottom portion by a tooth tip portion meshing with the tooth bottom portion, and the rotation operation between the outer rotor and the inner rotor can be performed smoothly without any hindrance. It can be done.

  According to the invention of claim 2, the pin member is non-uniformly attached to any of the plurality of tooth bottom portions of the outer rotor, so that the cell volume is further increased in irregularity and the pulsation peak is reduced. As a result, vibration and noise can be prevented. According to the third aspect of the present invention, it is possible to configure a protruding and protruding mechanism from the tooth bottom portion of the pin member with an extremely simple configuration.

  According to the invention of claim 4, since the plurality of pin members have different sizes of the protruding volume from the tooth bottom portion, the amount of oil inside the cell varies depending on the protruding volume amount of the pin member. Even in the cell to which the pin member is attached, the amount of oil can be kept constant, and irregularity can be further increased. According to a fifth aspect of the present invention, the pin member is formed in a cylindrical shape, so that the pin member can be smoothly projected and buried from the storage portion.

  According to the invention of claim 6, when the tip shape of the pin member is formed in a substantially spherical shape, when the tooth tip portion embeds the pin member in the storage portion, they can contact each other with little resistance, The pin member can be projected and buried satisfactorily. When the pin member is attached to the tooth bottom portion on the outer rotor side, when cavitation occurs in the cell, bubbles generated in the oil are concentrated on the tooth bottom portion side of the inner rotor, and the oil liquid portion Will concentrate on the tooth bottom side of the outer rotor. Therefore, the substantial decrease in the volume of the liquid part changes due to the protruding part of the pin member mounted on the outer rotor side, making the change in the oil amount of the cell even more irregular, and causing the pulsation peak. It can reduce and prevent vibration and noise.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1A, the oil pump of the present invention is one in which a trochoidal tooth-shaped outer rotor 1 and inner rotor 2 are housed in a rotor chamber 61 formed in a housing 6. The rotor chamber 61 is formed as a flat cylindrical recess. As shown in FIGS. 2A and 2B, the rotor chamber 61 includes a circular bottom surface 611 and a circumferential inner peripheral wall surface 612. It is configured. A bearing portion 64 is formed at the center of the bottom surface 611 of the rotor chamber 61, and a suction port 62 and a discharge port 63 are formed on the bottom surface 611 of the rotor chamber 61 along the circumferential direction substantially near the outer periphery. ing.

  A relief groove 7 is formed in the inner peripheral wall surface 612 along the circumferential direction of the inner peripheral wall surface 612. The escape groove 7 is open toward the center of the rotor chamber 61. The escape groove 7 is formed so as to communicate with a communication hole 42 of the pin housing recess 4 formed in the outer rotor 1 described later. The cross-sectional shape of the escape groove 7 is a rectangular or square shape (see FIG. 2B). Further, the sectional shape of the escape groove 7 may be a substantially semicircular shape or a substantially triangular shape. Further, the escape groove 7 has a structure that does not communicate with the discharge port 63.

  The suction port 62 and the discharge port 63 are formed in the rotor chamber 61 in a substantially asymmetrical manner. A first seal land 65 formed between the end portion 622 of the suction port 62 and the start end portion 631 of the discharge port 63, and the end portion 632 of the discharge port 63 and the start end portion 621 of the suction port 62 A second seal land 66 is formed therebetween. The start end portion 621 and the end end portion 622 of the suction port 62 are positions determined along the rotation direction of the outer rotor 1 and the inner rotor 2 (see FIG. 2A).

  That is, when the outer rotor 1 and the inner rotor 2 rotate, the first position where the arbitrarily determined cell S enters the suction port 62 is the start end 621, and exits from the suction port 62. The last position is the end portion 622. Similarly, the start end portion 631 and the end end portion 632 of the discharge port 63 are also positions determined along the rotation direction of the outer rotor 1 and the inner rotor 2.

  As shown in FIG. 1A, the inner rotor 2 is one less in number of teeth than the outer rotor 1, and when the inner rotor 2 rotates once, the outer rotor 1 rotates with a delay. As described above, the outer rotor 1 is formed with the inner tooth portion 11 protruding from the inner peripheral side toward the center side, and the inner tooth portion 11 is constituted by the tooth tip portion 111 and the concave tooth bottom portion 112. Further, as shown in FIG. 1A, the inner rotor 2 has an outer tooth portion 21 formed on the outer periphery, a tooth tip portion 211 protruding outward, and a concave tooth bottom portion 212 on the inner side. . When the outer rotor 1 and the inner rotor 2 rotate together, the outer tooth portion 21 of the inner rotor 2 and the inner tooth portion 11 of the outer rotor 1 are combined to form an interdental space. Hereinafter, this interdental space is referred to as a cell S. In particular, the volume of the cell S gradually decreases from the vicinity of the first seal land 65, and oil is discharged to the discharge port 63.

  Between the end portion 622 of the suction port 62 and the start end portion 631 of the discharge port 63, a first seal land 65 serving as a partition portion for partitioning the suction port 62 and the discharge port 63 is formed [ See FIG. 2A]. Further, a second seal land 66 is formed between the terminal end portion 632 of the discharge port 63 and the start end portion 621 of the suction port 62, which serves as a partition portion for separating the suction port 62 and the discharge port 63. [See FIG. 2A]. In the process of transferring the fluid sucked by the suction port 62 to the discharge port 63 by the cell S formed by the outer rotor 1 and the inner rotor 2, the cell S moves in the formation region of the first seal land 65. In the meantime, a room that becomes a closed gap is formed.

  The second seal land 66 is a portion through which the cell S discharges oil to the discharge port 63 and passes after the discharge operation of the cell S is moved again to the suction port 62 side. Here, the rotation direction of the inner rotor 2 and the outer rotor 1 is assumed to rotate counterclockwise in FIGS. 1 (A) and 2 (A). When the formation positions of the suction port 62 and the discharge port 63 are opposite to each other, the rotation directions of the inner rotor 2 and the outer rotor 1 are clockwise.

  Next, as shown in FIG. 1, a pin member 3 is attached to the tooth bottom portion 112 of the outer rotor 1. The pin member 3 always protrudes from the surface of the tooth bottom portion 112, and is pressed by the tooth tip portion 211 of the inner rotor 2 meshing with the tooth bottom portion 112, whereby the pin member 3 is moved to the tooth bottom portion. The structure can be buried in 112 [see FIGS. 5A to 5C].

  As shown in FIGS. 1 (B) and 1 (C), the pin member 3 has a pin housing recess 4 in which the pin member 3 is housed. Has been. The pin member 3 is formed in a substantially cylindrical shape. The pin housing recess 4 is formed as a cylindrical hole-shaped depression. It is preferable that the inner diameter of the pin housing recess 4 is formed so as to have a clearance t such that the pin member 3 has no backlash and can slide smoothly in the axial direction. As will be described later, the gap t serves as a flow path for allowing the oil in the cell S to flow into the pin housing recess 4, and also serves as a lubricating oil for the movement of the pin member 3 in and out of the oil. You can have it.

  The pin member 3 is housed in the pin housing recess 4 via an elastic member 5. Specifically, as shown in FIGS. 3A and 3B, the elastic member 5 is disposed between the pin member 3 and the bottom surface of the pin housing recess 4. The elastic member 5 is preferably a coil spring. The elastic member 5 that is a coil spring is fixed to a fixing portion 411 formed on the bottom 41 of the pin housing recess 4 at one end in the longitudinal direction. The fixing portion 411 of the pin housing recess 4 is formed in a recess shape or a protrusion shape, and in the case of the recess shape, the outer side of the elastic member 5 serving as a coil spring is fitted and fixed in a press-fitted state. In addition, although not particularly illustrated, when the fixing portion 411 of the pin housing recess 4 has a protruding shape, the inside of the elastic member 5 serving as the coil spring is fitted and fixed in a press-fitted state.

  The connection between the elastic member 5 and the pin member 3 is the same as the connection structure with the pin housing recess 4. The pin member 3 has a hollow portion 31 formed therein, and the other end in the longitudinal direction of the elastic member 5 serving as the coil spring is fixed to a fixing portion 311 formed inside the pin member 3. The fixing portion 311 is formed in a recessed shape or a protruding shape, similar to the fixing portion 411. In the case where the fixing portion 311 has a concave shape, the outer diameter of the coil spring (elastic member 5) is fitted and fixed in a press-fitted state. Thus, as shown in FIGS. 1B and 1C, the pin member 3 is formed from the opening (the surface of the tooth bottom 112) of the pin housing recess 4 formed in the tooth bottom 112. The elastic member 5 always protrudes. And it can be embedded in the pin accommodation recessed part 4 so that it may be pushed in by the tooth tip part 211 of the inner rotor 2 which meshes with the tooth bottom part 112 of the outer rotor 1 (refer to FIGS. 5B and 5C). .

  A communication hole 42 is formed in the bottom 41 of the pin receiving recess 4 as shown in FIGS. The communication hole 42 is a part that plays a role of sending oil accumulated in the pin housing recess 4 from the outside of the outer rotor 1 to the escape groove 7. The communication hole 42 is formed along the direction in which the pin member 3 protrudes and is buried (in / out direction). Moreover, it is preferable that the shape of the front-end | tip part 32 of the said pin member 3 is formed in a substantially spherical shape.

  By forming the tip portion 32 in a spherical shape, the tooth tip portion 211 (or the tooth tip portion 111) that meshes with the tooth bottom portion 112 (or the tooth bottom portion 212) on which the pin member 3 is mounted becomes the pin member 3. When being pressed and buried in the pin housing recess 4, the pin member 3 can be smoothly buried in the pin housing recess 4 without causing large mutual friction [FIGS. 5A to 5C]. reference〕. Furthermore, the tooth tip portion 111 (or the tooth tip portion 211) gradually moves away from the pin member 3 once buried, and the pin member 3 does not jump out of the pin housing recess 4 and protrudes relatively slowly. be able to.

  As shown in FIGS. 1A and 4A, the pin member 3 and the pin housing recess 4 are mounted at a plurality of locations with respect to all the tooth bottom portions 112, 112,... Of the outer rotor 1, And it is preferable to arrange irregularly. Further, as shown in FIG. 4B, the pin member 3 has different sizes, and these are attached to the plurality of tooth bottom portions 112, 112,... At irregular intervals. The The size of the volume is determined by the size (size) of the pin member 3. This volume has a large diameter Da and a small diameter Db, and there are a long dimension La and a short dimension Lb in the axial length.

  The amount by which the pin member 3 protrudes from the tooth bottom 112 is determined by the size of the diameter and length. A portion where the pin member 3 protrudes from the opening of the pin housing recess 4 (that is, the surface of the tooth bottom 112) is the volume of the pin member 3 in the cell S. Hereinafter, the amount of the protruding volume is referred to as a protruding volume Pv as shown in FIG. Further, the outer dimensions of the pin member 3 may include a medium size in addition to the two types of large and small. Thus, the size of the protruding volume Pv of the cell can be further increased or decreased depending on the size of the outer dimension of the pin member 3.

  When the pin member 3 is attached to any tooth bottom portion 112 only on the outer rotor 1 side, when cavitation occurs in the cell, bubbles generated in the oil are generated in the tooth bottom portion 212 of the inner rotor 2. In addition, the liquid portion of the oil is concentrated on the tooth bottom portion 112 of the outer rotor 1. Therefore, the reduction in the volume of the liquid portion of the oil changes depending on the protruding volume Pv of the pin member 3 when the pin member 3 is mounted on the outer rotor 1 side. The amount Q of oil in the cell S formed by the tooth bottom portion 112 to which the pin member 3 is mounted is defined as follows. When the volume at an arbitrary position of the cell S is Sv, the amount Q of oil in the cell S is (Q = Sv−Pv) (see FIGS. 3C and 6A). The protruding volume Pv varies depending on the size of the pin member 3, making the change in the amount Q of oil inside the cell S even more irregular, reducing the pulsation peak, and preventing vibration and noise. can do.

  In the present invention, when the outer rotor 1 and the inner rotor 2 rotate together, when the oil is discharged to the discharge port 63 side at the location where the cell S constituted by both rotors has the maximum volume, the cell S The discharge amount in the discharge operation performed at once changes depending on the presence or absence of the pin member 3. That is, as shown in FIG. 6A, the amount Q of oil in the cell S is reduced by the volume of the portion protruding from the tooth bottom portion 112 (or the tooth bottom portion 212) of the pin member 3 (projection volume Pv). become. Further, the amount Q of oil in the cell S constituted by the tooth bottom portion 112 to which the pin member 3 is not mounted is equal to the volume Sv of the cell S (see FIG. 6B).

  As a result, the amount of oil Q discharged from the cell S to the discharge port 63 varies irregularly depending on the presence or absence of the pin member 3 in the tooth bottom 112 of the outer rotor 1, and the oil from the cell S to the discharge port 63 regularly. Compared with the case of discharging, the pulsation peak is reduced or does not occur, and vibration and noise can be prevented. Thus, the pin member 3 has an oil amount Q of Sv−Pv due to the amount of protrusion from the tooth bottom 112 of the outer rotor 1, that is, the protrusion volume Pv, and enters the discharge port 63 from the first seal land 65. The amount Q of the oil in the cell S in the stage is not always uniform, and the amount Q can be varied, thereby making the oil supply from the cell S to the suction port 62 irregular and causing a pulsation peak. The reduction can protect the pump body and peripheral devices.

  Further, when the cell S formed by the outer rotor 1 and the inner rotor 2 passes through the second seal land 66, the volume of the cell S is minimized. In this case, FIGS. ), The tooth tip portion 211 of the inner rotor 2 bites into the tooth bottom portion 112 of the outer rotor 1, and the pin member 3 can be pushed into the pin housing recess 4 so as to be buried. The rotor 1 and the inner rotor 2 perform smooth rotation.

  Due to the pin member 3 protruding into the cell S, part of the oil flows from the gap t between the pin member 3 and the pin housing recess 4. Further, when the cell S contracts, the pin member 3 is pushed into the pin housing recess 4 by the tooth tip portion 211 of the inner rotor 2. At this time, the oil accumulated in the pin housing recess 4 is pressed by the pin member 3 and pushed out from the communication hole 42 into the escape groove 7 (see FIGS. 5B and 5C). Thus, the pin member 3 can be prevented from becoming buried due to the reaction force caused by the oil accumulated in the pin housing recess 4, and the pin member 3 can be easily housed in the pin housing recess 4. Can do.

  Further, the oil accumulated in the pin housing recess 4 flows into the escape groove 7 and is sucked into the suction port 62 side through the escape groove 7 and into the cell S in the negative pressure state. [Refer to FIG. 4A]. As a result, the oil pushed out from the inside of the pin housing recess 4 can flow into the escape groove 7 and flow into the other pin housing recess 4, and the pin member 3 performs a stable projecting operation. It is something that can be done. Further, since the escape groove 7 is configured not to communicate with the discharge port 63, the oil that has flowed into the escape groove 7 does not flow into the discharge port 63. This keeps the irregularity of the oil quantity Q.

(A) is the top view made into the partial cross section of this invention, (B) is Xa-Xa arrow sectional drawing of (A), (C) is Xb-Xb arrow sectional drawing of (B). (A) is a principal part top view of a casing, (B) is Xc-Xc arrow sectional drawing of (A). (A) is the principal part expanded sectional view of the state which the pin member protruded from the tooth bottom part in this invention, (B) is the principal part enlarged sectional view of the state where the (A) pin member was buried in the tooth bottom part, (C) FIG. 5 is an enlarged cross-sectional view showing the amount of oil in the cell with the pin member protruding. (A) is a schematic diagram showing the action of the relief groove, (B) is an enlarged cross-sectional view showing the dimensions of the pin members of various sizes. (A) thru | or (C) are stroke diagrams which show the state which a pin member embeds in a tooth bottom part. (A) is a state diagram immediately before a cell constituted by a tooth bottom portion to which a pin member is attached reaches a discharge port, and (B) is a cell constituted by a tooth bottom portion to which a pin member is not attached reaches a discharge port. It is a state diagram immediately before.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer rotor, 112 ... Tooth bottom part, 2 ... Inner rotor, 3 ... Pin member,
DESCRIPTION OF SYMBOLS 4 ... Pin accommodation recessed part, 42 ... Communication hole, 61 ... Rotor chamber, 612 ... Inner peripheral wall surface, 62 ... Suction port, 63 ... Discharge port, 7 ... Escape groove

Claims (6)

  A rotor chamber having a suction port and a discharge port and having a circular inner peripheral wall surface; a relief groove formed along the circumferential direction of the inner peripheral wall surface and not communicating with the discharge port; and an inner rotor; An outer rotor that rotates while forming a cell together with the inner rotor, a pin storage recess formed in any tooth bottom portion of the outer rotor, and a pin storage recess that is stored in the pin storage recess and constantly from the surface of the tooth bottom portion. A pin member that protrudes and is buried in the pin housing recess by a tooth tip portion of the inner rotor, and a communication hole that communicates with the relief groove is formed in the pin housing recess. Inscribed gear pump.   2. The internal gear pump according to claim 1, wherein the pin member is attached to any of a plurality of tooth bottom portions of the outer rotor.   3. The internal gear pump according to claim 1, wherein the pin member is provided with an elastic member between the pin housing recess and the pin member.   4. The internal gear pump according to claim 1, wherein the plurality of pin members have different sizes of protruding volumes from the tooth bottom portion.   5. The internal gear pump according to claim 1, wherein the pin member is formed in a cylindrical shape. 6. 6. The internal gear pump according to claim 1, wherein the tip shape of the pin member is formed in a substantially spherical shape.

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