JP2005105995A - Internal gear pump and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear pump capable of increasing production efficiency and reducing cost and a method of manufacturing the internal gear pump. <P>SOLUTION: The axis of a disk-like casing 10 is set to a first center O1, and a second center O2 is set to a position eccentric from the first center O1. A recessed part 12 for an outer rotor and a recessed part 13 for a cover are formed concentrically with the first center O1, and a hole 21 for a shaft concentrical to the second center O2 is formed in the cover 20 fitted to the recessed part 13 for the cover. The outer rotor 30 is fitted to the recessed part 12 for the outer rotor, an inner rotor 40 is stored in the outer rotor 30, and the cover 20 is fixedly fitted to the recessed part 13 for the cover. The shaft 50 passed through the hole 21 for the shaft in the cover 20 is fixed to the inner rotor 40, and the shaft 50 is disposed concentrically with the second center O2. Thus, the recessed part 12 for the outer rotor and the recessed part 13 for the cover can be formed by concentric machining and eccentric machining can be eliminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal gear pump suitable for pumping fluid such as lubricating oil and a method for manufacturing the same.

  As this type of pump, a trochoid pump is known in which an outer rotor and an inner rotor having a trochoidal tooth profile are rotatably accommodated in a casing. A plurality of inner teeth are formed on the inner peripheral portion of the outer rotor, and an outer tooth having one fewer teeth than the inner teeth of the outer rotor is formed on the outer peripheral portion of the inner rotor, and the inner rotor is accommodated in a state in which it is inscribed A suction-side volume chamber and a discharge-side volume chamber are formed between partition points where the two rotors contact each other. When the inner rotor is rotated, the outer rotor is rotated in the same direction while the outer teeth mesh with the inner teeth of the outer rotor, and the fluid is sucked into the suction-side volume chamber where the volume increases, and the volume decreases. In this configuration, the suctioned fluid is discharged from the side volume chamber.

  FIG. 3 shows an example of a conventional trochoid pump: (a) a front view of the casing, (b) a longitudinal sectional view of the casing, (c) a front view of the cover, and (d) a longitudinal sectional view of the entire pump. is there. In this pump, an outer rotor 62 and an inner rotor 63 are accommodated in an outer rotor recess 61 formed on one end surface of a disc-shaped casing 60, and the outer rotor recess 61 is closed by a cover 65 fitted to the cover recess 64. The shaft 65 passes through the cover 65, the inner rotor 63 and the casing 60, and the shaft 66 rotates to rotate the inner rotor 63 and the outer rotor 62. As shown in FIG. 3A, a suction port 67 and a discharge port 68 that communicate with the outer rotor recess 61 from the back side are formed at the bottom of the outer rotor recess 61. Normally, the shaft 66 passes through the axial center of the casing 60, and therefore the shaft hole 69 of the casing 60 is formed in the axial center of the casing 60, and accordingly, the cover 65, the cover recess 64, and the cover 65 are formed. The shaft hole 70 is also formed and disposed concentrically with the casing 60. Only the outer rotor recess 61 is eccentric by a length L with respect to the axial center of the casing 60, and the outer rotor 62 is rotated in an eccentric manner with respect to the shaft 66 in the outer rotor recess 61. Such a trochoid pump is known from Patent Document 1, for example.

JP 59-90788 (FIG. 4)

In order to form an eccentric outer rotor in the above-described conventional trochoid pump casing, first, an outer diameter surface of a small-diameter portion projecting concentrically with the shaft center is processed on the back side, and this outer diameter surface is utilized. The casing is set on an eccentric rotating jig, and a cutting tool such as a cutting tool is advanced into the casing while the casing is eccentrically rotated, and is formed by cutting. On the other hand, machining parts other than the outer rotor recesses (shaft holes, cover recesses, etc.) can be processed concentrically with reference to the axial center of the casing. That is, since the eccentric processing of the concave portion for the outer rotor and the concentric processing of the other portions are performed, two steps of the eccentric processing and the concentric processing are required. there were.
Accordingly, an object of the present invention is to provide an internal gear pump that can improve production efficiency and reduce costs, and a method for manufacturing the internal gear pump.

  In the internal gear pump of the present invention, a circular outer rotor recess provided in a casing is rotatably fitted with an outer rotor having internal teeth, has external teeth, and a shaft is fixed to the shaft center thereof. The inner rotor is accommodated in the outer rotor so as to be rotatable in contact with the inner teeth of the outer rotor around the second center that is eccentric to the first center that is the center of the outer rotor, and the shaft is rotated. Thus, by rotating the inner rotor and the outer rotor meshing with the inner rotor, a suction side volume chamber for sucking fluid and a discharge side volume chamber for discharging fluid are formed between the inner teeth and the outer teeth. In the contact gear pump, the casing has a circular outer rotor recess and a cover recess concentrically formed on one end surface with respect to the first center. A cover for closing the concave portion for the outer rotor is fitted and fixed. The cover is formed with a shaft hole concentrically formed with respect to the second center in the fixed state. By passing through the shaft hole, the cover is held concentrically with respect to the second center.

  The shaft for driving the inner rotor is disposed concentrically with the second center by passing through the cover recess for the cover, and the outer rotor recess formed concentrically with the first center, and the outer rotor recess The outer rotor fitted to the shaft is eccentric with respect to the shaft as before. According to the present invention, the outer rotor concave portion and the cover concave portion of the casing are formed by concentric processing based on the first center set in the casing, and therefore it is not necessary to form the outer rotor concave portion by eccentric processing. . And it is not necessary to form the hole for shafts in a casing. On the other hand, the cover is provided with an eccentric shaft hole centered on the second center in a circular outer shape centered on the first center, but by means such as casting, punching, or powder metallurgy. Since the shaft hole can be formed at a time, the number of processes does not increase.

  The internal gear pump of the present invention includes a configuration in which the cover is positioned with respect to the casing by using positioning means such as concave-convex fitting so that the shaft is also positioned. Further, since the casing has a disk shape and the center of the outer diameter is the first center, the concentric processing can be performed with the outer diameter surface as a reference, so that the processing is further facilitated.

  Next, in the manufacturing method of the internal gear pump of the present invention, in manufacturing the internal gear pump of the present invention, the casing is set on the rotating jig with reference to the outer diameter surface of the casing, and the rotating jig A casing in which the outer rotor recess and / or the cover recess are cut concentrically with respect to the first center while rotating the casing around the first center, and a circular outer shape concentric with the first center and The second center and a cover in which a concentric shaft hole is formed at the same time are used. In this method, the casing is preferably provided with means for positioning the casing with respect to the rotating jig, that is, means for aligning the first center with the center of the rotating jig.

  According to the present invention, the concave portion for the outer rotor formed in the casing can be formed by concentric processing together with other concentric portions, and the manufacturing process is not required to form the shaft hole in the casing. This simplifies the production efficiency and reduces the cost.

Hereinafter, the best mode for carrying out the present invention will be described.
1A to 1D are views showing the configuration of the trochoid pump 1 of the present embodiment, in which FIG. 1D is a longitudinal sectional view of the whole, and FIG. 1A is a casing 10 constituting the trochoid pump 1. The front view seen from one end surface, (b) is the longitudinal cross-sectional view of the casing 10, (c) is the front view which looked at the cover 20 which comprises the trochoid pump 1 from one end surface. As shown in FIG. 1 (d), the trochoid pump 1 includes a casing 10, a cover 20, an outer rotor 30, an inner rotor 40, and a shaft 50. FIG. 2 is a front view of the outer rotor 30 and the inner rotor 40.

  As shown in FIGS. 1A and 1B, the casing 10 has a disk shape in which a small-diameter portion 11 protrudes from the back surface (the other end surface), and is one end surface side opposite to the small-diameter portion 11. In addition, a circular outer rotor recess 12 and a cover recess 13 are formed. These recesses 12 and 13 are formed concentrically with respect to the first center O1, which is the axis of the casing 10, by cutting. A suction port 14 and a discharge port 15 that communicate with the outer rotor recess 12 from the back side are formed at the bottom of the outer rotor recess 12. A cover 20 is fitted and fixed to the cover recess 13, and the outer rotor recess 12 is closed by the cover 20. A plurality (three in this case) of mounting holes 16 are formed in the outer peripheral portion of the casing 10. These mounting holes 16 are bolt through holes for mounting the trochoid pump 1 to the device, and are spaced equidistantly in the circumferential direction around the second center O2 that is eccentric by a length L with respect to the first center O1. Formed. Although the form and arrangement of the suction port and the discharge port are arbitrary, FIG. 1A shows that the suction port 14 and the discharge port 15 are symmetrical with respect to a line connecting the first center O1 and the second center O2. It is an example formed symmetrically. Further, the small diameter portion 11 is formed concentrically with the second center O2.

  A positioning groove 17 extending in the axial direction is formed at a predetermined location on the outer diameter surface 19 of the casing 10. In this case, a line passing through the center of the mounting hole 16 closest to the outer diameter surface 19 on the upper side in FIG. 1 and the first and second centers O1 and O2 is formed on the outer diameter surface 19 on the first center O1 side. Positioning grooves 17 are formed at the intersecting positions. Further, a semicircular cutout 18 is formed at a predetermined location on the inner peripheral surface of the outer rotor recess 12 by casting. For this casing 10, for example, a cast product formed by an aluminum die casting method is used. In this case, the shape excluding the outer rotor recess 12 and the cover recess 13 is formed by die molding.

  The outer rotor 30 is rotatably fitted in the outer rotor recess 12, and the inner rotor 40 is rotatably accommodated in the outer rotor 30 while being inscribed therein. As shown in FIG. 2, the outer rotor 30 has a ring shape and a plurality of inner teeth 31 are formed on the inner peripheral portion thereof. The inner rotor 40 has a shaft fitting that concentrically fixes the shaft 50 and the inner rotor 40 to the shaft center. An outer tooth 41 having a hole 42 and having one fewer tooth than the inner tooth 31 of the outer rotor 30 is formed on the outer periphery thereof. The internal teeth 31 and the external teeth 41 are in contact with each other at a partition point P, and a space formed between the partition points P and the cover 20 is formed as a volume chamber R on the suction side or the discharge side. As the outer rotor 30 and the inner rotor 40, sintered products or the like are used.

  As shown in FIG. 1C, the cover 20 has a circular shaft hole 21 through which the shaft 50 passes. A projection 22 that fits into the notch 18 of the casing 10 is formed at a predetermined position on the outer peripheral edge of the cover 20. When this protrusion 22 is fitted into the notch 18 and the cover 20 is fitted into the cover recess 13, the shaft hole 21 is arranged concentrically with respect to the second center O 2. As a result, the shaft 50 can be easily and reliably disposed concentrically with the second center O2. The cover 20 is manufactured by punching a sheet metal, for example, and the shaft hole 21 can be formed at a time with a circular outer shape.

  The trochoid pump 1 comprising the above-described components is assembled as follows. First, the outer rotor 30 is fitted into the outer rotor recess 12 of the casing 10, and the inner rotor 40 is accommodated in the outer rotor 30. Next, the shaft 50 is passed through the shaft hole 21 of the cover 20, the tip end portion of the shaft 50 is fitted into the shaft fitting hole 42 of the inner rotor 40, and the protrusion 22 is fitted into the notch 18 to cover the cover 20. Is fitted into the cover recess 13. Thereafter, the cover 20 is fixed by caulking an appropriate portion of the opening edge of the cover recess 13 to the cover 20. The trochoid pump 1 assembled in this way is attached to a device using the attachment hole 16 of the casing 10. Since the plurality of mounting holes 16 are arranged concentrically with the second center O2 in the same manner as the shaft 50, the trochoid pump 1 is mounted on the apparatus with the shaft 50 as a reference, and the shaft 50 is connected to the cover 20. Held by. Since the outer rotor 30 is fitted into the outer rotor recess 12 concentrically formed with respect to the first center O1, the outer rotor 30 is eccentrically disposed with respect to the shaft 50 as in the conventional art.

  In the trochoid pump 1, the shaft 50 is rotated by a driving source such as a motor, and the inner rotor 40 is rotated. Accordingly, the outer rotor 30 is rotated in the same direction while the outer teeth 41 are engaged with the inner teeth 31. Here, the volume chamber R formed between the partition points P is formed with a suction side where the volume increases and a discharge side where the volume decreases according to the rotation direction of the rotors 30 and 40. Therefore, the rotation direction of the shaft 50 and the suction port 14 and the discharge port 15 are set so that the suction side volume chamber is disposed on the suction port 14 side and the discharge side volume chamber is disposed on the discharge port 15 side. . As the rotors 30 and 40 rotate, a state in which the suction-side volume chamber communicates with the suction port 14 repeatedly occurs from a state in which the suction-side volume chamber communicates with the suction port 14. The pump action is continuously performed in which the fluid is sucked and the sucked fluid is discharged from the discharge-side volume chamber.

  According to the trochoid pump 1 of the present embodiment, the outer rotor concave portion 12 and the cover concave portion 13 of the casing 10 can be formed by concentric processing based on the first center O1 set in the casing 10. Thus, it is not necessary to form the outer rotor recess 12 by eccentric machining. Further, it is not necessary to form the shaft hole 21 in the casing 10. Therefore, the manufacturing process of the casing 10 is simplified, thereby improving the production efficiency and reducing the cost.

  In forming the outer rotor concave portion 12 and the cover concave portion 13 of the casing 10, the first center is attached to the rotary jig for cutting on the basis of the outer diameter surface 19 which is finished with high accuracy by die molding. There is a method in which the casing 10 is set so that O1 becomes the center of rotation, and a cutting tool such as a cutting tool is advanced to perform cutting while rotating the casing 10 with a rotating jig. In that case, if the positioning groove 17 formed on the outer diameter surface 19 is used so that the first center O1 can be aligned with the center of the rotating jig, the setting to the rotating jig is facilitated.

  Although the embodiments embodying the present invention have been described above, the present invention is not limited to the above-described embodiments regarding the tooth profile shape of the outer rotor and the inner rotor, the arrangement and shape of the suction port and the discharge port, and the like. Various forms that have been proposed and adopted in the past can be applied.

1 is a trochoid pump according to an embodiment of the present invention, wherein (a) is a front view of the casing, (b) is a longitudinal sectional view of the casing, (c) is a front view of the cover, and (d) a longitudinal sectional view of the entire pump. It is. It is a front view of the outer rotor and inner rotor of the trochoid pump of an embodiment. An example of the conventional trochoid pump is shown, (a) is a front view of the casing, (b) is a longitudinal sectional view of the casing, (c) is a front view of the cover, and (d) is a longitudinal sectional view of the entire pump. .

Explanation of symbols

1 ... Trochoid pump (internal gear pump)
10 ... casing,
12 ... Recess for outer rotor 13 ... Recess for cover 17 ... Positioning groove (casing positioning means)
DESCRIPTION OF SYMBOLS 19 ... Outer surface 20 ... Cover 21 ... Hole for shafts 22 ... Protrusion (cover positioning means)
DESCRIPTION OF SYMBOLS 30 ... Outer rotor 31 ... Inner tooth 40 ... Inner rotor 41 ... Outer tooth 50 ... Shaft O1 ... 1st center O2 ... 2nd center R ... Volume chamber

Claims (6)

An outer rotor having internal teeth is rotatably fitted to a circular outer rotor recess provided in the casing, and
An inner rotor having outer teeth, the shaft of which is fixed to the shaft center of the inner rotor, is centered around a second center that is eccentric to the first center that is the center of the outer rotor. It is inscribed with the tooth and accommodated in a rotatable manner,
By rotating the inner rotor and the outer rotor meshing with the inner rotor by rotating the shaft, a suction side volume chamber for sucking fluid between the inner teeth and the outer teeth, and a discharge for discharging the fluid In the internal gear pump in which the side volume chamber is formed,
In the casing, a circular outer rotor recess and a cover recess are formed concentrically with respect to the first center on one end surface,
A cover for closing the outer rotor concave portion is fitted and fixed to the cover concave portion, and a shaft hole concentrically formed with respect to the second center in the fixed state is formed in the cover. And
The internal gear pump, wherein the shaft is held concentrically with the second center by passing through the shaft hole of the cover.   The internal gear pump according to claim 1, further comprising positioning means for the cover with respect to the casing.   The internal gear pump according to claim 1 or 2, wherein the casing has a disk shape, and the center of the outer diameter is the first center. In manufacturing the internal gear pump according to claim 1,
The casing is set on a rotation jig with reference to the outer diameter surface of the casing, and the outer rotor recess and / or the cover recess is rotated while rotating the casing around the first center by the rotation jig. A casing cut concentrically with respect to the first center;
A method for manufacturing an internal gear pump, comprising: a circular outer shape concentric with the first center and the cover in which the shaft hole concentric with the second center is formed at a time.   5. The method for manufacturing an internal gear pump according to claim 4, wherein the cover is formed by casting, punching, or powder metallurgy. The method for manufacturing an internal gear pump according to claim 4 or 5, wherein the casing has a positioning means for the casing with respect to the rotating jig.

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