JP5834627B2 - Gear pump - Google Patents

Description

  The present invention relates to a gear pump.

In the gear pump, a pump housing, a pump plate, an outer rotor that is rotatably fitted in a rotor built-in space formed between the two, an inner rotor having outer teeth that mesh with inner teeth of the outer rotor, and an inner rotor shaft A structure having a drive shaft that is inserted into a hole so as to transmit torque and rotates an inner rotor is known.
In the gear pump having such a structure, in order to fit the shaft hole of the inner rotor and the drive shaft so that torque can be transmitted, a flat surface chamfered in the axial direction of the outer peripheral surface of the tip end portion of the drive shaft is formed, The shaft hole of the inner rotor is formed in a non-circular shape corresponding to the cross-sectional shape of the tip portion of the drive shaft.
In the gear pump having such a structure, wear powder may be generated on the inner peripheral surface of the shaft hole of the inner rotor due to the contact frictional force of the fitting portion between the shaft hole of the inner rotor and the drive shaft.
In particular, when the drive shaft is made of steel and the inner rotor is made of an aluminum alloy, the flat portion of the inner peripheral surface of the shaft hole of the inner rotor is likely to be worn by the edge portion of the flat surface of the drive shaft.
When wear powder is generated on the inner peripheral surface of the shaft hole of the inner rotor, it is assumed that the wear powder promotes wear of a flat portion of the inner peripheral surface of the shaft hole of the inner rotor.
Further, in a gear pump in which the drive shaft is made of steel and the inner rotor is made of an aluminum alloy, for example, a gear pump disclosed in Patent Document 1 is known in order to prevent wear on the flat portion of the inner peripheral surface of the shaft hole of the inner rotor. It has been.
In this case, a wear-resistant member is assembled to the flat portion of the inner peripheral surface of the shaft hole of the inner rotor.

JP-A-11-107933

  By the way, in the gear pump disclosed by patent document 1, abrasion can be suppressed by assembling | attaching an abrasion-resistant member to the flat part of the internal peripheral surface of the shaft hole of an inner rotor. However, the number of parts and the number of assembling steps increase as the wear-resistant member is manufactured and assembled to the flat portion of the inner peripheral surface of the shaft hole of the inner rotor, which increases the cost.

  In view of the above problems, an object of the present invention is to provide a gear pump that can suppress wear of a fitting portion between a shaft hole of an inner rotor and a drive shaft with an extremely simple structure.

In order to solve the above-mentioned problem, a gear pump according to a first aspect of the present invention includes a pump housing having a recess opening on one end side, and a rotor built-in space that is attached to one end of the pump housing and closes the recess. And a pump plate in which a suction port and a discharge port are respectively formed on a surface facing the pump housing, an outer rotor that is rotatably fitted in the rotor built-in space, and an inner tooth of the outer rotor. An inner rotor having external teeth, and a drive shaft that rotates through the inner rotor through a through-hole formed in the bottom wall of the recess of the pump housing and inserted into the shaft hole of the inner rotor in a noncircular cross-sectional shape so that torque can be transmitted A gear pump with
A space portion is formed in the shaft hole of the inner rotor between the front end surface of the drive shaft that is inserted into the shaft hole and the inner end surface of the pump plate. Abrasion powder generated on the inner peripheral surface of the shaft hole is removed from the location,
An exhaust passage for the wear powder is formed between the pump plate and the inner rotor, and one end of the escape passage communicates with the space portion and the other end communicates with the suction port.

According to the above configuration, even if wear powder is generated on the inner peripheral surface of the shaft hole of the inner rotor, the wear powder is formed between the front end surface of the drive shaft and the inner end surface of the pump plate and the pump plate. It is released in the escape passage between the inner rotor and. For this reason, it is possible to prevent wear on the inner peripheral surface of the shaft hole of the inner rotor from being promoted by the wear powder. That is, the wear of the fitting portion between the shaft hole of the inner rotor and the drive shaft can be suppressed with an extremely simple structure without increasing the number of parts and the number of assembly steps.

Moreover, according to the said structure, the abrasion powder generate | occur | produced on the internal peripheral surface of the shaft hole of an inner rotor flows in from one end of an escape path, and flows toward the other end. The abrasion powder that has reached the escape path flows to the suction port. For this reason, it is possible to prevent the abrasion powder generated on the inner peripheral surface of the shaft hole of the inner rotor from staying at the peripheral portion of the shaft hole.

A gear pump according to claim 2 is the gear pump according to claim 1 ,
The escape path is constituted by a recessed groove-like escape groove formed on the inner end face of the pump plate and one end face of the inner rotor that closes the groove opening of the escape groove.

  According to the said structure, an escape path can be easily comprised by the recessed groove-shaped escape groove of the inner end surface of a pump plate, and the one end surface of an inner rotor.

It is a front view which shows the assembly | attachment state of the pump housing of the gear pump which concerns on Example 1 of this invention, an outer rotor, and an inner rotor. It is sectional drawing which follows the II-II line of FIG. 1 which similarly shows the whole gear pump. It is sectional drawing which follows the III-III line | wire of FIG. 1 which similarly shows the whole gear pump. It is a perspective view which similarly shows a pump plate. FIG. 5 is an enlarged longitudinal sectional view showing a state where an escape path as an escape portion is configured by cooperation of the escape groove of the pump plate and the end face of the inner rotor.

  A mode for carrying out the present invention will be described in accordance with an embodiment.

A gear pump according to Embodiment 1 of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the gear pump includes a pump housing 10, a pump plate 20, an outer rotor 30, an inner rotor 35, and a drive shaft 50.
The pump housing 10 includes a disk-shaped bottom wall 11 and a peripheral wall 13 formed in a cylindrical shape along the peripheral edge of the bottom wall 11, and a recess that opens to one end side by the bottom wall 11 and the peripheral wall 13. 14 is formed.
Further, the bottom wall 11 is formed with a through hole 12 having a center at a position eccentric from the center by an amount corresponding to an eccentric amount A between the outer rotor 30 and the inner rotor 35 described in detail later.

The pump plate 20 is attached to the end face of the peripheral wall 13 of the pump housing 10 in a sealing manner by bolts or the like (not shown), and the recess 14 of the pump housing 10 is closed to constitute the rotor built-in space 15.
As shown in FIGS. 3 and 4, the surface of the pump plate 20 facing the pump housing 10 (hereinafter referred to as an inner end surface) is mainly composed of a suction port groove 22 having a circular front shape. A suction port 21 and a discharge port 25 mainly composed of a discharge port groove 26 whose front shape forms an arc shape are formed to face each other.
The pump plate 20 is formed with a suction port hole 23 penetratingly formed at the center of the arc of the suction port groove 22, and at the center of the arc of the discharge port groove 26. 27 is formed in a penetrating shape.
The suction port groove 22 and the suction port hole 23 constitute the suction port 21, and the discharge port groove 26 and the discharge port hole 27 constitute the discharge port 25.

As shown in FIGS. 1 to 3, the outer rotor 30 is rotatably fitted in the rotor built-in space 15. A plurality of internal teeth 31 are formed in the circumferential direction of the inner peripheral surface of the outer rotor 30.
The inner rotor 35 is incorporated into the inner peripheral surface of the outer rotor 30 in an eccentric state by an eccentric amount A, and a plurality of external teeth 36 that mesh with the plurality of inner teeth 31 of the outer rotor 30 are formed in the circumferential direction of the outer peripheral surface. Yes. A closed space 40 is formed between the inner teeth 31 of the outer rotor 30 and the outer teeth 36 of the inner rotor 35.
A non-circular shaft hole 37 is formed at the center of the inner rotor 35, and the tip shaft portion 50 a of the drive shaft 50 is fitted into the shaft hole 37 through the through hole 12 of the pump housing 10 so that torque can be transmitted.
In the first embodiment, a flat surface 51 that is chamfered in the axial direction of the outer peripheral surface of the distal end shaft portion 50 a of the drive shaft 50 is formed, and the inner peripheral surface of the shaft hole 37 has a shaft at a position facing the flat surface 51. A flat portion 38 is formed so as to form an arc string of the hole 37.
When the inner rotor 35 rotates upon receiving torque transmission from the drive shaft 50, the outer rotor 30 follows and rotates with the outer teeth 36 of the inner rotor 35 meshing with the inner teeth 31 of the outer rotor 30. Eggplant.
In the first embodiment, the drive shaft 50 is made of steel, and the inner rotor 35 (and the outer rotor 30) is made of an aluminum alloy.

As shown in FIGS. 4 and 5, an escape path 61 serving as an escape portion 60 is provided between the pump plate 20 and the inner rotor 35 to release wear powder generated on the inner peripheral surface of the shaft hole 37 of the inner rotor 35. Is formed. One end of the escape path 61 communicates with a space portion 55 (a part of the shaft hole 37) between the distal end surface of the distal end shaft portion 50a of the drive shaft 50 and the inner end surface of the pump plate 20, and the other end is a suction port. 21 communicates.
The escape path 61 is constituted by a recessed groove-like escape groove 62 formed on the inner end face of the pump plate 20 and one end face 35 a of the inner rotor 35 that closes the groove opening of the escape groove 62.

The gear pump according to the first embodiment is configured as described above.
Therefore, when the drive shaft 50 rotates upon receiving power transmission from the drive source, torque is transmitted at the fitting portion between the tip shaft portion 50a of the drive shaft 50 and the shaft hole 37 of the inner rotor 35, and the inner rotor 35 rotates. Accordingly, the outer rotor 30 follows and rotates, so that the fluid (for example, oil) supplied to the suction port 21 passes through the closed space 40 between the inner teeth 31 of the outer rotor 30 and the outer teeth 36 of the inner rotor 35, and is discharged from the discharge port. 25.

Since the drive shaft 50 is made of steel and the inner rotor 35 is made of an aluminum alloy, when torque is transmitted at the fitting portion between the tip shaft portion 50a of the drive shaft 50 and the shaft hole 37 of the inner rotor 35 and the inner rotor 35 rotates, The flat portion 38 of the shaft hole 37 of the inner rotor 35 may be worn by the edge portion of the flat surface 51 of the tip shaft portion 50 a of the drive shaft 50, and wear powder may be generated on the inner peripheral surface of the shaft hole 37.
In this case, the abrasion powder flows from one end of the escape path 61 as the escape portion 60 toward the other end, and then flows into the suction port 21 and is released.
For this reason, it is possible to prevent the abrasion powder generated on the inner peripheral surface of the shaft hole 37 of the inner rotor 35 from staying in the peripheral portion of the shaft hole 37. As a result, it is possible to prevent wear on the inner peripheral surface of the shaft hole 37 from being promoted by the wear powder.
In the first embodiment, the escape path 61 can be easily configured by the recessed groove-like escape groove 62 on the inner end face of the pump plate 20 and one end face of the inner rotor 35.

In addition, this invention is not limited to the said Example 1, In the range which does not deviate from the summary of this invention, it can implement with a various form.
For example, in the first embodiment, the case where the suction port and the discharge port are not formed on the bottom wall 11 of the pump housing 10 is illustrated. However, the pump facing the suction port 21 and the discharge port 25 of the pump plate 20 respectively. A suction port and a discharge port may be formed in each part of the bottom wall 11 of the housing 10.
Further, a space portion may be formed between the pump plate 20 and the inner rotor 35 and on the outer periphery of the shaft hole 37, and the space portion may constitute an escape portion for wear powder. In this case, it is desirable to arrange an adsorbing member capable of adsorbing the wear powder in the space portion forming the escape portion.

DESCRIPTION OF SYMBOLS 10 Pump housing 11 Bottom wall 12 Through-hole 13 Perimeter wall 14 Recessed part 15 Rotor built-in space 20 Pump plate 21 Suction port 25 Discharge port 30 Outer rotor 31 Inner tooth 35 Inner rotor 36 Outer tooth 37 Shaft hole 38 Flat part 50 Drive shaft 51 Flat surface 60 Relief part 61 Relief path 62 Relief groove

Claims (2)

A pump housing having a recess that opens on one end side, a rotor built-in space that is attached to one end of the pump housing and that closes the recess, and a suction port and a discharge port on a surface facing the pump housing Are formed on the bottom wall of the recess of the pump housing, the inner rotor having outer teeth meshing with the inner teeth of the outer rotor, and the outer rotor that is rotatably fitted in the rotor built-in space. A gear pump including a drive shaft that passes through a through-hole and is fitted and inserted in a non-circular cross-sectional shape so as to transmit torque to the shaft hole of the inner rotor, and rotates the inner rotor;
A space portion is formed in the shaft hole of the inner rotor between the front end surface of the drive shaft that is inserted into the shaft hole and the inner end surface of the pump plate. Abrasion powder generated on the inner peripheral surface of the shaft hole is removed from the location,
An exhaust passage for the wear powder is formed between the pump plate and the inner rotor, and one end of the escape passage communicates with the space portion and the other end communicates with the suction port. A gear pump characterized by The gear pump according to claim 1,
The escape path is constituted by a recessed groove-shaped escape groove formed on the inner end face of the pump plate and one end face of an inner rotor that closes the groove opening of the escape groove .

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