JP2533422Y2 - Internal gear pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an internally meshing internal gear pump used as a hydraulic pressure source attached to a vehicle, a machine tool, or the like.

[Conventional technology]

Conventionally, this type of internal gear pump is rotatably eccentric with each other so that an internal gear having internal teeth and an external gear having external teeth are inscribedly engaged with each other in a cylindrical hole formed in the pump body. The cover member is fixed to the side surface of the pump body where the cylindrical hole is opened by a plurality of fastening bolts so as to close the opening, and the internal gear is rotated by driving the external gear so that the internal gear has an inner peripheral surface of the cylindrical hole. Are slidably contacted and driven to rotate in the same direction, so that a liquid suction / discharge action can be obtained.

[Problems to be solved by the invention]

However, in such a configuration, the portion of the pump body to which the fastening bolt is screwed is distorted due to the fastening force of the fastening bolt for fixing the lid member, and the inner peripheral surface opening side of the cylindrical hole is locally inward. In order to obtain smooth sliding contact of the internal gear, the minimum arrangement size of the fastening bolt with respect to the inner peripheral surface of the cylindrical hole is limited, and there is a problem that it is difficult to reduce the external shape of the internal gear pump. .

The present invention has been made to solve the above problem, and has as its object to provide an internal gear pump which can be easily reduced in size at low cost.

[Means for solving the problem]

For this reason, in the present invention, an internal gear having an internal tooth and an external gear having an external tooth are eccentrically rotatably provided so as to internally mesh with a cylindrical hole formed in the pump body. A plurality of screw holes formed on a side surface of the opening pump body and having a lid member joined thereto so as to close the opening, and formed at equal intervals in the circumferential direction in parallel with the axis of the cylindrical hole near the outer periphery of the cylindrical hole of the pump body. The cover member is fixed to the side surface of the pump body by screwing a fastening bolt to the outer peripheral surface of the internal gear, which is slidably in contact with the inner peripheral surface of the cylindrical hole. Is formed.

[Action]

In the configuration of the present invention, a tapered surface is formed on the outer peripheral surface of the internal gear that is rotatably provided in the cylindrical hole so as to reduce the diameter toward the opening side of the cylindrical hole on the outer peripheral surface that is in sliding contact with the inner peripheral surface of the cylindrical hole.
Even if the inner peripheral surface opening side of the cylindrical hole is locally deformed inward due to the tightening force of the fastening bolt for fixing the lid member, the internal gear is affected by the deformation by the tapered surface of the outer peripheral surface. It becomes difficult and can rotate smoothly. Therefore, with a very simple shape change to provide a tapered surface on the outer peripheral surface of the internal gear,
The minimum arrangement size of the fastening bolt with respect to the inner peripheral surface of the cylindrical hole can be reduced, and the outer shape of the internal gear pump can be easily reduced in size at low cost.

〔Example〕

Hereinafter, an embodiment in which the present invention is used for an engine lubricating oil pump will be described.

1 to 3, reference numeral 1 denotes a pump main body, which is disposed on a side of the body 2 constituting an engine on which an output shaft 3 protrudes. The pump main body 1 accommodates a gear of a pump means therein. A plurality of screw holes 5 are formed in the inner side surface on the side of the fuselage 2 by disposing the cylindrical hole 4 and a plurality of screw holes 5 near the outer periphery of the cylindrical hole 4 at equal intervals in the circumferential direction in parallel with the axis of the cylindrical hole 4.
A bearing hole that is connected to the bottom surface of the cylindrical hole 4 so that the output shaft 3 can be freely inserted.
11 are provided. 6 is an internal gear having internal teeth, 7 is an external gear having external teeth one less than the number of teeth of the internal gear 6,
The two gears 6 and 7 have substantially the same width and are formed to have a width slightly smaller than the depth of the cylindrical hole 4, and are eccentrically rotatable relative to each other so as to mesh with the cylindrical hole 4. ing.
On the outer peripheral surface of the internal gear 6 which is in sliding contact with the inner peripheral surface of the cylindrical hole 4, a tapered surface 8 is formed which is inclined toward the opening side from the inside of the cylindrical hole 4 while leaving a sliding contact portion of the bearing. Further, the external gear 7 is provided so as to fit the shaft portion 12 into the bearing hole 11 so as to be mounted on the shaft and engage with the output shaft 3. 9 is a lubricating oil suction path,
Numeral 10 is a lubricating oil discharge path, both of which are formed substantially symmetrically at the bottom of the cylindrical hole 4 and are opened so that the engine lubricating oil can be sucked and discharged by rotation of both gears 6 and 7. Reference numeral 13 denotes a cover member which is joined to the inner side surface of the pump body 1 to close the opening of the cylindrical hole 4 and is provided so as to be in contact with the side surfaces of both gears 6 and 7 to constitute a pump means. The lid member 13 is fixed by a plurality of fastening bolts 14 screwed into the screw holes 5. An oil seal 15 is provided to prevent oil from leaking from the outer peripheral surface of the output shaft 3 penetrating the pump body 1.

 Next, the operation of this configuration will be described.

In the illustrated state, when the external gear 7 is rotated in the downward direction by the arrow in FIG.
Due to the internal meshing, the internal gear 6 is driven to rotate in the same direction as the external gear 7, and the lubricating oil is sucked and discharged. In this operation, the distortion of the pump main body 1 caused by the fastening force of the fastening bolt 14 to the screw hole 5 causes the inner peripheral surface of the cylindrical hole 4 to be partially inwardly directed toward the inner peripheral surface as shown in FIG. A bulge deformation G occurs. The internal gear 6 can be smoothly driven and rotated by the remaining sliding contact portion of the outer peripheral surface without being affected by the bulging portion G due to the tapered surface 8 formed on the outer peripheral surface. For this reason, the minimum arrangement size of the fastening bolt 14 with respect to the inner peripheral surface of the cylindrical hole 4 can be reduced, and a very simple shape change in which the tapered surface 8 is provided on the outer peripheral surface of the internal gear 6 can be achieved. Thus, the external shape of the internal gear pump can be easily reduced in size.
Further, by obtaining a smaller outer shape, the weight of the entire pump can be reduced, and in combination with the downsizing, an optimum design according to the application can be easily performed, and the application can be expanded.

[Effect of the invention]

As described above, according to the present invention, the internal gear and the external gear are eccentric to each other so as to internally mesh with each other, and are rotatably housed. The cover member is joined and arranged, and fastening bolts are screwed into a plurality of screw holes formed in the vicinity of the outer periphery of the cylindrical hole of the pump body at equal circumferential intervals in parallel with the axis of the cylindrical hole. Is fixed to the side surface of the pump body, and a tapered surface is formed on the outer peripheral surface which is in sliding contact with the inner peripheral surface of the cylindrical hole of the internal gear so as to taper toward the opening side of the cylindrical hole to reduce the tightening force of the fastening bolt. Since the resulting distortion hardly affects the rotation of the internal gear, the fastening bolt can be easily arranged near the outer periphery of the cylindrical hole, and the outer shape of the internal gear pump can be easily reduced in size at low cost. In addition, the overall size of the pump can be reduced by downsizing the outer shape, and in combination with the downsizing, it is easy to carry out an optimal design according to the application, and this has an excellent practical effect such that the application can be expanded.

[Brief description of the drawings]

The drawing shows an internal gear pump showing one embodiment of the present invention,
FIG. 2 is a partial longitudinal sectional view, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is an enlarged sectional view of a main part A of FIG. 1 ... pump body, 4 ... cylindrical hole, 5 ... screw hole, 6 ...
... internal gear, 7 ... external gear, 8 ... taper surface, 13 ...
Lid member, 14 fastening bolts

Claims (1)

(57) [Scope of request for utility model registration] An internal gear having internal teeth and an external gear having external teeth are eccentrically rotatably provided in a cylindrical hole formed in a pump body so as to be in mesh with an internal gear. A lid member is jointly arranged on the side surface of the pump body to close the opening, and a plurality of screw holes formed in the vicinity of the outer periphery of the cylindrical hole of the pump body at equal intervals in the circumferential direction and parallel to the axis of the cylindrical hole. The lid member is fixedly provided on the side surface of the pump body by screwing a fastening bolt, and a tapered surface which is inclined toward the opening side of the cylindrical hole on the outer peripheral surface which is in sliding contact with the inner peripheral surface of the cylindrical hole of the internal gear is provided. Internal gear pump formed