JP2009138528A - Internal gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear pump capable of suppressing abnormal abrasion and seizure caused by the intrusion of foreign matters into a space between an inner peripheral surface of a pump housing and an outer peripheral surface of an outer rotor slidably abutting on the inner peripheral surface without causing the enlargement of a pump shape. <P>SOLUTION: An annular recession groove 25 is formed on the inner peripheral surface 24 of the pump housing 3 along an outer peripheral direction. Therefore, the foreign matters intruding into the recession groove 25 of the foreign matters intruding into the space between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface 23 of the outer rotor 22 stay in the recession groove 25 without returning to the slidably abutting part between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface 23 of the outer rotor 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal gear pump, and more particularly to an internal gear pump that suppresses wear and seizure due to sucked foreign matter.

  In general, an internal gear pump is widely used as an oil pump that circulates oil having a relatively high viscosity. Normally, a filter for removing foreign substances is provided on the oil suction side of this inscribed gear pump, but even when such a filter is provided, the maximum pore diameter of the filter into the pump chamber It is difficult to completely prevent the following foreign substances from flowing in. In particular, if foreign matter enters between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor that is in sliding contact with the inner peripheral surface, the foreign matter cannot be easily removed, and the foreign matter is In addition, there is a problem that the outer peripheral surface of the outer rotor continues to wear. Therefore, abnormal wear occurs in the pump housing and the outer rotor, and seizure may occur.

In order to avoid these disadvantages, there has been proposed a technique for removing foreign matter that has entered between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor that is in sliding contact with the inner peripheral surface. More specifically, in the internal gear pump of the type having outer teeth on the outer peripheral surface of the outer rotor, a separate second external rotor is added, and foreign matter that has entered between the outer teeth of the outer rotor is removed from the suction passage side. The technique of removing by pushing out is proposed (for example, patent document 1).
Japanese Patent Laid-Open No. 11-247765

  However, the technique shown in Patent Document 1 increases the pump scale by adding a separate second external rotor. Further, it can be applied only to an inscribed gear pump of a type having outer teeth on the outer peripheral surface of the outer rotor. Therefore, even in the case where the technique described in Patent Document 1 is applied to an internal gear pump that does not have external teeth on the outer peripheral surface of the outer rotor, it is still difficult to avoid the above disadvantages. It was.

  Therefore, the present invention has been made in view of the above-described problems, and can be applied to an inscribed gear pump of a type that does not have external teeth on the outer peripheral surface of the outer rotor. To provide an internal gear pump that suppresses the occurrence of abnormal wear and seizure caused by the intrusion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor that is in sliding contact with the inner peripheral surface It is in.

  An inscribed gear pump according to the present invention includes a substantially bottomed cylindrical pump housing, a short cylindrical shape having an inner tooth on an inner peripheral surface, and an outer surface whose outer peripheral surface is in sliding contact with the inner peripheral surface of the pump housing. The internal gear pump includes a rotor and a short columnar shape having external teeth on the outer peripheral surface, and the external teeth are meshed with the inner teeth of the outer rotor. In addition, a foreign matter container for collecting foreign matter that has entered the sliding contact portions of the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor is provided.

  According to the above configuration, since the foreign matter storage portion for collecting foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor is provided, the sliding contact between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor The foreign matter that has entered the portion can be captured and accommodated in the foreign matter accommodation portion. Therefore, the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor can be prevented from being damaged by foreign matters, and the occurrence of abnormal wear and seizure caused by the entry of foreign matters can be suppressed. Since it is not necessary to add special parts for the entry of foreign matter, the pump shape does not increase in size.

  It is preferable that the foreign matter container of the inscribed gear pump according to the present invention is an annular concave groove provided along the circumferential direction on the inner peripheral surface of the pump housing. According to the above configuration, the foreign material container is an annular concave groove provided along the circumferential direction on the inner peripheral surface of the pump housing, and thus can be easily configured by casting, grinding, or the like. In addition, when foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor moves in the axial direction, it can be easily captured in the foreign matter storage portion.

  The foreign matter container of the inscribed gear pump according to the present invention is preferably a linear groove provided in the central axis direction on the inner peripheral surface of the pump housing. According to the above configuration, the foreign substance storage portion is a straight concave groove provided in the central axis direction on the inner peripheral surface of the pump housing, and thus can be easily configured by casting, grinding, or the like. Further, when foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor moves in the circumferential direction, it can be easily captured in the foreign matter storage portion.

  According to the present invention, abnormal wear caused by foreign matter entering between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor that is in sliding contact with the inner peripheral surface without increasing the size of the pump. It is possible to provide an inscribed gear pump that suppresses occurrence of seizure and seizure.

  An embodiment of an internal gear type oil pump embodying the present invention will be described below with reference to FIG.

  An internal gear type oil pump housing 1 according to the present embodiment has a shape in which a bottomed substantially cylindrical motor housing 2 is sealed by a bottom portion of a bottomed substantially cylindrical pump housing 3. A stator 5 that generates electromagnetic force is fixed to the inner peripheral surface 4 of the motor housing 2 by a method such as press-fitting, bonding, and screwing. A cylindrical protrusion 6 is provided on the inner surface 42 of the substantially disc-shaped bottom 41 of the motor housing 2, and the rolling bearing 7 is provided on the inner peripheral surface 6a of the protrusion 6 by a clearance fit, a tight fit or the like. It is fixed. Further, the rolling bearing 7 supports a rear end 9 which is one end of the rotary shaft 8. A rotor 10, which is a permanent magnet, is fixed to the outer peripheral surface of the central portion in the longitudinal direction of the rotating shaft 8 so as to face the stator 5.

  On the other hand, the pump housing 3 has a substantially cylindrical shape with a bottom, and the opening of the motor housing 2 is sealed by the disc-shaped bottom portion 11 of the pump housing 3. A cylindrical projecting portion 12 is provided on the outer surface 11a of the bottom portion 11, and a rolling bearing 13 is fixed to the inner peripheral surface 12a of the projecting portion 12 by clearance fitting, interference fitting or the like. Further, a front end 14, which is one end of the rotary shaft 8, is supported by the rolling bearing 13. A through hole 15 is provided at the center of the bottom 11 of the pump housing 3, and the front end 14 of the rotating shaft 8 protrudes toward the inside of the pump housing 3 through the through hole 15.

  A substantially short cylindrical inner rotor 20 having a through-hole 21 at the center is externally fitted to the front end 14 of the rotary shaft 8 protruding toward the inside of the pump housing 3. As the rotary shaft 8 rotates, it rotates. External teeth are provided on the outer peripheral surface of the inner rotor 20, and internal teeth of the substantially annular outer rotor 22 are meshed with the external teeth. The outer peripheral surface 23 of the outer rotor 22 is in sliding contact with the inner peripheral surface 24 of the substantially cylindrical pump housing 3. An annular groove 25 is formed in the inner circumferential surface 24 of the pump housing 3 along the outer circumferential direction, and this groove 25 supplements and accommodates foreign matter that has entered the sliding contact portion of the outer circumferential surface of the outer rotor. It functions as a foreign matter storage part.

  A substantially disc-shaped lid 30 is fixed to the opening of the pump housing 3 to form a pump chamber having the inner rotor 20 and the outer rotor 22 therein. The lid 30 is provided with a suction port 31 and a discharge port 32, both of which are through holes.

  When electric power is supplied to the oil pump having the above structure, electromagnetic force is generated in the stator 5, and the rotor 10 made of a permanent magnet rotates with the rotating shaft 8. For this reason, after the inner rotor 20 fixed to the rotating shaft 8 and the outer rotor 22 meshing with the inner rotor 20 rotate, the lubricating oil is sucked into the pump housing through the suction port 31 and pressurized, It is discharged through the discharge port 32.

  Here, in the internal gear type oil pump of the present embodiment, the annular groove 25 is formed in the inner peripheral surface 24 of the pump housing 3 as described above. Therefore, even if foreign matter enters between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface 23 of the outer rotor 22, the foreign matter enters the concave groove 25 and enters the concave groove 25. The foreign matter can be supplemented and accommodated by the concave groove 25. Accordingly, it is possible to suppress the foreign matter once captured and accommodated by the concave groove 25 from entering between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface 23 of the outer rotor 22. As a result, unlike the above-described prior art, it is possible to effectively suppress the occurrence of damage and seizure of the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface 23 of the outer rotor 22 due to the invading foreign matter. It becomes possible.

  The size of the groove 25 is not particularly limited, but it is preferable to form the groove 25 as large as possible from the viewpoint of capturing a large amount of foreign matter. On the other hand, since the inner peripheral surface 24 of the pump housing 3 has a function as a flat bearing, the provision of the concave groove 25 may cause a decrease in strength. Further, considering the functional aspect of the oil pump, providing the concave groove 25 can be a factor of reducing the sealing performance. Accordingly, the concave groove 25 is formed to the maximum extent that the reduction in strength of the pump housing 3 is not a problem and the sealing performance of the sliding contact portion between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface of the outer rotor 22 is not a problem. It is preferable to form large.

  According to the electric oil pump of the above embodiment, the following effects can be obtained.

(1) According to the electric oil pump of the embodiment, since the foreign matter containing portion that supplements and contains the foreign matter that has entered the sliding contact portion between the inner peripheral surface 24 of the pump housing 3 and the outer peripheral surface of the outer rotor is provided. Foreign matter that has entered the sliding contact portions of the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor can be supplemented and stored in the foreign matter storage portion. Therefore, the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor can be prevented from being damaged by foreign matters, and the occurrence of abnormal wear and seizure caused by the entry of foreign matters can be suppressed. Since there is no need to add special parts for the entry of foreign matter, the pump shape does not increase in size.

  (2) According to the electric oil pump of the embodiment, the foreign substance container is an annular concave groove 25 provided along the circumferential direction on the inner peripheral surface 24 of the pump housing 3, so that casting, It can be easily formed by grinding or the like. In addition, when foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor moves in the axial direction, it can be easily captured in the foreign matter storage portion.

  In addition, you may change the said embodiment as follows.

  In the above-described embodiment, the annular concave groove 25 provided along the circumferential direction is provided on the inner peripheral surface of the pump housing 3 as the foreign substance storage portion, but other configurations may be used. For example, a linear groove may be provided in the axial direction. When foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor moves in the circumferential direction, it can be easily captured in the foreign matter storage portion.

  In the above-described embodiment, the annular concave groove 25 provided along the circumferential direction is provided on the inner peripheral surface of the pump housing 3 as the foreign substance storage portion, but other configurations may be used. For example, an annular concave groove 25 may be provided on the outer peripheral surface of the outer rotor. Even if it is this form, a foreign material accommodating part can be comprised easily. Moreover, when the foreign material which penetrate | invaded into the sliding contact part of the inner peripheral surface of a pump housing and the outer peripheral surface of an outer rotor moves to an axial direction, it can be easily capture | acquired by a foreign material storage part.

  In the above modification, the annular groove 25 is provided on the outer peripheral surface of the outer rotor, but other configurations may be used. For example, a linear groove in the axial direction may be provided on the outer peripheral surface of the outer rotor. Even if it is this form, a foreign material accommodating part can be comprised easily. Moreover, when the foreign material which penetrate | invaded into the sliding contact part of the inner peripheral surface of a pump housing and the outer peripheral surface of an outer rotor moves to the circumferential direction, it can be easily capture | acquired by a foreign material storage part.

  -In the said embodiment and the said modification, although one foreign material accommodating part is provided, you may provide multiple. For example, as shown in FIG. 2, by providing two concave grooves 25, 25, foreign matter that has entered between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor can be more efficiently collected in the concave grooves. it can. Accordingly, it is possible to further prevent foreign matters from being damaged on the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor.

  Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.

  (A) It is preferable that the internal gear pump according to the present invention includes a plurality of the foreign matter storage portions. Therefore, according to the invention described in (a), since a plurality of foreign matter storage portions are provided, the foreign matter that has entered between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor is more efficiently recessed. Can be supplemented and housed.

  (B) It is preferable that the foreign matter storage part of the inscribed gear pump according to the present invention is an annular concave groove provided along the circumferential direction on the outer peripheral surface of the outer rotor. Therefore, according to the invention described in (b), since the foreign material container is an annular groove provided in the outer circumferential surface of the outer rotor along the circumferential direction, it can be easily obtained by casting, grinding, or the like. Can be formed. Moreover, when the foreign material which infiltrated the sliding contact part of the inner peripheral surface of a pump housing and the outer peripheral surface of an outer rotor moves to the direction to spread, it can be easily capture | acquired by the foreign material storage part.

  (C) It is preferable that the foreign matter container of the internal gear pump according to the present invention is a linear groove provided in the central axis direction on the inner peripheral surface of the pump housing. Therefore, according to the invention described in (c), the foreign material container is a straight concave groove provided in the central axis direction on the outer peripheral surface of the outer rotor, and thus can be easily configured. Further, when foreign matter that has entered the sliding contact portion between the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor moves in the circumferential direction, it can be easily captured in the foreign matter storage portion.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an inscribed gear pump used for an oil pump or the like, and is a technique for suppressing wear and seizure due to sucked foreign matter, and thus can be widely used in industry.

The axial sectional view showing the structure about one embodiment of the internal gear pump concerning the present invention. The axial direction sectional view which shows the structure about another example of the internal gear pump concerning this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Motor housing, 3 ... Pump housing, 4 ... Inner peripheral surface, 5 ... Stator, 6 ... Projection part, 6a ... Inner peripheral surface, 7 ... Bearing, 8 ... Rotating shaft, 9 ... Rear end, 10 DESCRIPTION OF SYMBOLS ... Rotor, 11 ... Bottom part, 11a ... Outer surface, 12 ... Projection part, 12a ... Inner peripheral surface, 13 ... Rolling bearing, 14 ... Front end, 15 ... Through-hole, 20 ... Inner rotor, 21 ... Through-hole, 22 ... Outer rotor, 23 ... outer peripheral surface, 24 ... inner peripheral surface, 25 ... concave groove, 30 ... lid, 31 ... suction port, 32 ... discharge port, 41 ... bottom, 42 ... inner surface.

Claims (3)

A substantially bottomed cylindrical pump housing;
An outer rotor having a short cylindrical shape and having inner teeth on the inner peripheral surface, and an outer peripheral surface slidingly contacting the inner peripheral surface of the pump housing;
In the internal gear pump having a short cylindrical shape and having outer teeth on the outer peripheral surface, the outer teeth including an inner rotor meshing with the inner teeth of the outer rotor,
An internal gear pump characterized in that a foreign matter accommodating portion is provided for supplementing and accommodating foreign matter that has entered the sliding contact portions of the inner peripheral surface of the pump housing and the outer peripheral surface of the outer rotor.   2. The inscribed gear pump according to claim 1, wherein the foreign substance accommodating portion is an annular concave groove provided along a circumferential direction of the inner peripheral surface on the inner peripheral surface of the pump housing. .   The inscribed gear pump according to claim 1, wherein the foreign substance accommodating portion is a linear concave groove provided in the central axis direction of the pump housing on the inner peripheral surface of the pump housing.

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