JP2011231705A - Inscribed gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inscribed gear pump comprising a driven gear with internal teeth, a drive gear with external teeth to be meshed with the inside thereof, and a pump housing for housing them, configured to perform rotational driving using the drive gear as a drive shaft, to reduce vibration and noise caused by gear meshing and to improve durability of the pump.SOLUTION: An annular groove 15 is formed to surround the whole circumference of the outer peripheral surface 8a of the driven gear, on one or both of the outer peripheral surface 8a of the driven gear and the inner peripheral surface 7a of the pump housing. A plurality of recessed grooves 16 are formed that extend from the annular groove 15 to one inside surface 7b of the pump housing. A discharge pressure guide path 17 is formed at the pump housing from a discharge port 14 to at least one of the plurality of recessed grooves 16.

Description

  The present invention relates to an internal gear pump used for, for example, a lubricating oil pump in an internal combustion engine.

  As is well known in the art, this type of internal gear pump includes a pump casing, an internal gear driven gear housed in a pump housing provided in the pump casing in a freely rotating state, and the driven gear. A drive gear having an external tooth with a smaller diameter than the driven gear and meshing with the driven gear. The driven gear and the drive gear are rotatably incorporated in the pump housing of the pump casing, and the axial direction of the pump housing A suction port and a discharge port are opened on at least one of the left and right inner side surfaces of the left and right sides, and the drive gear is driven to rotate by a drive shaft so that a working fluid such as oil is sucked from the suction port. And it is set as the structure discharged from the said discharge port.

  Further, in this type of internal gear pump, between the left and right outer surfaces of the driven gear and the left and right inner surfaces of the pump housing, and between the outer peripheral surface of the driven gear and the inner peripheral surface of the pump housing. By providing a slight clearance, the driven gear can be rotated smoothly to facilitate assembly.

  For this reason, the driven gear tilts to the left and right with respect to the axis of rotation, repeats this tilt to the left and right, shifts so as to be eccentric in the radial direction with respect to the center of rotation, and repeats this eccentricity. Therefore, the collision or impact of the tooth meshing with the drive gear is increased, and not only the vibration and noise caused by the meshing increase, but also the durability decreases.

  Therefore, in Patent Document 1 as the prior art, a plurality of recessed grooves communicating between the left and right outer surfaces of the driven gear are provided on the outer peripheral surface of the driven gear so as to act on the left and right outer surfaces of the driven gear. It has been proposed to reduce the inclination of the driven gear with respect to the rotational axis by eliminating the differential pressure between the driven gears.

  Further, Patent Document 2 as another prior art discloses that the driven gear and a pump that rotatably accommodates the driven gear by providing a plurality of recessed grooves extending spirally in the axial direction on the outer peripheral surface of the driven gear. It has been proposed to improve the lubrication between the housing and reduce frictional resistance.

JP 2007-023975 A JP 2003-176790 A

  However, in each of these prior arts, the plurality of recessed grooves provided on the outer peripheral surface of the driven gear eliminates the pressure difference between the left and right outer surfaces of the driven gear or improves the lubrication to the outer peripheral surface of the driven gear. However, since each of the recessed grooves does not communicate with each other and there is a pressure difference between them, each recessed groove has a radius with respect to the outer peripheral surface of the driven gear. The pressure acting inward in the direction hardly contributes to uniformizing the pressure on the entire circumference of the outer peripheral surface.

  Therefore, according to the configuration of each of the prior arts, the driven gear does not eliminate or reduce the eccentricity in the radial direction with respect to the center of rotation. Therefore, the vibration and noise can be sufficiently reduced and the durability can be sufficiently improved. Could not be achieved.

  Further, in the conventional inscribed gear pump, the drive gear that is inscribed and meshed with the driven gear also has the right and left outer surfaces of the drive gear and the left and right inner surfaces of the pump housing as in the case of the driven gear. And between the inner peripheral surface of the drive gear and the outer peripheral surface of the drive shaft on which the drive gear is fitted, the driven gear is smoothly rotated and a slight clearance is provided to facilitate assembly. There was a similar problem due to the construction.

  This invention makes it the technical subject to provide the internal gear pump which eliminated these problems.

Claim 1 is to achieve the technical problem,
“A driven gear having an internal tooth and an external drive gear having a smaller diameter than the driven gear and having a smaller diameter and meshing with the driven gear, the driven gear being rotatably incorporated in a pump housing in a pump casing, A suction port and a discharge port are opened on at least one inner side surface of both the left and right inner side surfaces in the axial direction of the housing, and the drive gear is rotated by a drive shaft, whereby the working fluid is discharged from the suction port. In an internal gear pump configured to suck and discharge from the discharge port,
One or both of the outer peripheral surface of the driven gear and the inner peripheral surface of the pump housing are provided with an annular groove surrounding the entire outer periphery of the driven gear, while one of the outer peripheral surface of the driven gear and the inner peripheral surface of the pump housing. Or, in both of them, a concave groove extending in the axial direction is provided at a portion between the annular groove and one inner surface of the pump housing at a plurality of locations in the circumferential direction. A discharge pressure guiding path from the port to at least one of the recessed grooves is provided. "
It is characterized by that.

In order to achieve the technical problem, claim 2 provides:
“A driven gear having an internal tooth and an external drive gear having a smaller diameter than the driven gear and having a smaller diameter and meshing with the driven gear, the driven gear being rotatably incorporated in a pump housing in a pump casing, A suction port and a discharge port are opened on at least one inner side surface of both the left and right inner side surfaces in the axial direction of the housing, and the drive gear is rotated by a drive shaft, whereby the working fluid is discharged from the suction port. In an internal gear pump configured to suck and discharge from the discharge port,
One or both of the inner peripheral surface of the drive gear and the outer peripheral surface of the drive shaft are provided with an annular groove surrounding the entire circumference of the inner peripheral surface of the drive gear, while the inner peripheral surface of the drive gear and the drive shaft In one or both of the outer peripheral surfaces, recessed grooves extending in the axial direction are provided in a portion between the annular groove and one inner surface of the pump housing at a plurality of locations in the circumferential direction, and the pump housing In addition, a discharge pressure guide path from the discharge port to at least one of the recessed grooves is provided. "
It is characterized by that.

  The high pressure working fluid in the discharge port according to claim 1 passes through the discharge pressure guide path, and then passes through one of the plurality of recessed grooves and enters an annular groove surrounding the outer periphery of the driven gear. , After filling the entire circumferential direction in the annular groove, it is distributed to each of the plurality of recessed grooves, passes through all of the recessed grooves, and passes through one of the inner surfaces of the pump housing and the driven gear. Between one outer surface and the entire circumference, it is evenly supplied at various places.

  The working fluid supplied here pushes the driven gear in the thrust direction to bring the other outer surface of the driven gear into close contact with the other inner surface of the pump housing, so that the driven gear is inclined with respect to the rotation axis. It can be held so that there is nothing.

  On the other hand, the working fluid filled in the entire circumferential direction in the annular groove on the outer peripheral surface of the driven gear spreads evenly over the entire circumference of the outer peripheral surface of the driven gear, and with respect to the outer peripheral surface of the driven gear, Since the outer peripheral surface acts to press inward in the radial direction with a uniform force at various locations in the circumferential direction, the driven gear can be held so as not to be decentered in the radial direction from the center of rotation. .

  Thereby, in addition to being able to hold the driven gear so that it does not tilt with respect to its rotational axis and does not deviate with respect to its rotational center by utilizing the pressure at the discharge port, The working fluid that spreads evenly over the entire circumference of the outer peripheral surface of the driven gear also acts as a damper that absorbs and reduces the meshing impact between the driven gear and the drive gear. Can be greatly reduced, and durability can be greatly improved.

  According to a second aspect of the present invention, the high-pressure working fluid in the discharge port passes through the discharge pressure guide path, and then passes through one of the plurality of recessed grooves to surround the inner periphery of the drive gear. After entering the annular groove and filling the entire circumferential direction in the annular groove, it is distributed to each of the plurality of recessed grooves, and passes through all of the recessed grooves to pass through one inner surface of the pump housing. And one outer surface of the drive gear are supplied evenly over the entire circumference.

  Thereby, the drive gear can be held so as not to be inclined with respect to the rotation axis and to be eccentric with respect to the rotation center by utilizing the pressure at the discharge port. The working fluid that spreads evenly over the entire circumference of the inner peripheral surface of the drive gear acts as a damper that absorbs and reduces the meshing impact between the driven gear and the drive gear. In addition to greatly reducing noise, durability can be greatly improved.

  In particular, by combining the first and second aspects, both the driven gear and the drive gear can be held so as not to be inclined with respect to the rotation axis, and the radius from the rotation center can be maintained. Since it can be held so as not to be decentered in the direction, there is an advantage that the above-described effects, that is, vibration and noise due to meshing, and durability can be further promoted.

It is a vertical front view which shows 1st Embodiment. FIG. 2 is a sectional view taken along line II-II in FIG. 1. It is a perspective view which shows the driven gear in 1st Embodiment. It is an exploded view in a 1st embodiment. It is a vertical front view which shows 2nd Embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is a perspective view which shows the driven gear in 2nd Embodiment.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below of a drawing when an embodiment of the present invention is applied to an internal gear type lubricating oil pump for an internal combustion engine.

  1 to 4 show a first embodiment.

  In this figure, reference numeral 1 denotes a cylinder block in an internal combustion engine. A balance shaft 2 is supported on the cylinder block 1 with respect to a crankshaft (not shown) supported on the cylinder block 1. Is configured to be rotationally driven in synchronism with the crankshaft by power transmission by the gear mechanism 3 from the crankshaft.

  Reference numeral 4 denotes a lubricating oil pump attached to the cylinder block 1 so as to be rotationally driven by the balance shaft 2.

  The lubricating oil pump 4 is an internal gear type, and includes a pump casing 5. A pump housing 7 into which a drive shaft 6 that integrally protrudes from the balance shaft 2 is inserted is provided in the pump casing 5. The pump housing 7 is formed by a cylindrical inner peripheral surface 7 a and left and right inner side surfaces 7 b and 7 c perpendicular to the axis of the drive shaft 6. A driven gear 8 that is supported so as to rotate in a rotating manner and a drive gear 9 that is fitted to the drive shaft 6 so as to rotate together with the driven gear 8 are incorporated.

  The driven gear 8 has an internal tooth structure having a plurality of teeth inside, and includes an outer peripheral surface 8a slidably in contact with the inner peripheral surface 7a of the pump housing 7, and in addition to the left and right sides of the pump housing. Left and right outer side surfaces 8b and 8c are slidably contacting the inner side surfaces 7b and 7c.

  On the other hand, the drive gear 9 has a smaller diameter than the driven gear 8 and has an outer tooth configuration that is eccentrically meshed with the driven gear 8 and engages with the outer peripheral surface 6 a of the drive shaft 6. In addition to the inner peripheral surface 9a, the pump housing 7 includes left and right outer side surfaces 9b and 9c slidably contacting the left and right inner side surfaces 7b and 7c.

  In the illustrated embodiment, the pump housing 7 is formed by detachably attaching a cover plate 10 to the pump casing 5 by fastening screws 11 or the like. The other inner surface 7c of the pump housing 7 constitutes the inner surface. Needless to say, the pump housing 7 can be formed in a configuration other than that illustrated.

  Further, the pump casing 5 is provided with a suction port 13 to the meshing gap 12 between the driven gear 8 and the drive gear 9 and a discharge port 14 from the meshing gap 12 in both the left and right sides of the pump housing 7. One of the inner side surfaces 7b and 7c is provided so as to open to one inner side surface 7b, and the meshing gap 12 is provided at the location of the suction port 13 as the drive gear 9 is driven and rotated by the drive shaft 6. In this configuration, the working fluid is sucked in by being expanded, and the working fluid is discharged by being reduced at the discharge port 14.

  An annular groove 15 is provided on the outer peripheral surface 8a of the driven gear 8 so as to surround the entire periphery of the outer peripheral surface 8a. On the outer peripheral surface 8a of the driven gear 8, the annular groove 15 and the one outer A recessed groove 16 extending in the axial direction is provided at a plurality of equally divided locations in the circumferential direction at a portion between the side surface 8b.

  Further, a discharge pressure guide path 17 configured in a groove shape extending outward in the radial direction from the discharge port 14 is provided on one inner side surface 7 b of the pump housing 7.

  In this configuration, the driven gear 8 rotates following the drive rotation of the drive gear 9, and one of the plurality of recessed grooves 16 provided on the outer peripheral surface 8a is provided on the pump housing 7 side. When communicating with the discharge pressure guiding path 17, the high-pressure working fluid in the discharge port 14 passes through the discharge pressure guiding path 17 and one recessed groove 16 and enters the annular groove 15 surrounding the outer periphery of the driven gear 8. After filling the entire circumferential direction in the annular groove 15, it is distributed to each of the plurality of recessed grooves 16, passes through all of the recessed grooves 16 and passes through one inner surface 7 b of the pump housing 7. And the one outer surface 8b of the driven gear 8 are supplied evenly over the entire circumference.

  The working fluid supplied here pushes the driven gear 8 in the thrust direction so that the other outer surface 8 c of the driven gear 8 is brought into close contact with the other inner surface 7 c of the pump housing 7. It can hold | maintain so that it may not incline with respect to a rotating shaft line.

  On the other hand, the working fluid filled in the entire circumferential direction in the annular groove 15 on the outer peripheral surface 8 a of the driven gear 8 spreads evenly over the entire circumference of the outer peripheral surface 8 a of the driven gear 8. Since the outer peripheral surface 8a acts so as to press the outer peripheral surface 8a radially inward with an equal force at various locations in the circumferential direction, the driven gear 8 is eccentric in the radial direction from the center of rotation. It can be held so as not to slip.

  Further, the working fluid that has spread evenly over the entire circumference of the outer peripheral surface 8a of the driven gear 8 also acts as a damper that absorbs and relaxes the meshing impact between the driven gear 8 and the drive gear 9.

  In the first embodiment, as shown in the drawing, the annular groove 15 and the recessed grooves 16 are provided on the outer peripheral surface 8a of the driven gear 8, but the present invention is not limited to this. The annular groove 15 and each recessed groove 16 are provided on the inner peripheral surface 7a of the pump housing 7, or straddle both the outer peripheral surface 8a of the driven gear 8 and the inner peripheral surface 7a of the pump housing 7. It can be set as the structure provided in.

  Next, FIGS. 5 to 7 show a second embodiment of the present invention.

  In the second embodiment, the annular groove, the recessed groove, and the discharge pressure guiding path are provided on the drive gear 9 side of the external tooth instead of being provided on the driven gear 8 side of the internal tooth.

  That is, the inner peripheral surface 9a of the drive gear 9 is provided with an annular groove 18 that surrounds the entire periphery of the drive shaft 6 on which the drive gear 9 is fitted, while the inner peripheral surface 9a of the drive gear 9 is Among them, a concave groove 19 extending in the axial direction is provided at a portion between the annular groove 18 and the one outer surface 9b at a plurality of equally divided locations in the circumferential direction. The inner surface 7b is provided with a discharge pressure guiding path 20 configured in a groove shape extending radially inward from the discharge port 14, and the other structure is the same as that of the first embodiment. It is the same.

  In this second embodiment, the drive gear 9 is driven and rotated, and one of the plurality of recessed grooves 19 provided on the inner peripheral surface 9a is formed into one discharge groove 20 on the pump housing 7 side. , The high-pressure working fluid in the discharge port 14 passes through the discharge pressure guide path 20 and the one recessed groove 19 and enters the annular groove 18 surrounding the inner periphery of the drive gear 9. 18 is filled in the entire circumferential direction and distributed to each of the plurality of recessed grooves 19, and passes through all of the recessed grooves 19 to pass through the inner surface 7 b of the pump housing 7 and the drive. Between the outer side 9b of the gear 9 and the outer periphery of the drive gear 9, the other side of the drive gear 9 is uniformly supplied over the entire circumference, pressing the drive gear 9 in the thrust direction. Since adhering the 9c on the other inner surface 7c of the pump housing 7, the drive gear 9, it can be held so as not to tilt with respect to its axis of rotation.

  On the other hand, the working fluid filled in the entire circumferential direction in the annular groove 18 on the inner peripheral surface 9a of the drive gear 9 spreads evenly over the entire circumference of the inner peripheral surface 9a of the drive gear 9, The drive gear 9 acts on the inner peripheral surface 9a of the drive gear 9 so as to press the inner peripheral surface 9a outward in the radial direction with an equal force at various locations in the circumferential direction. It can hold | maintain so that it may not shift eccentrically from the rotation center in the radial direction. In addition, the working fluid that has spread evenly over the entire circumference of the inner peripheral surface 9 a of the drive gear 9 also acts as a damper that absorbs and reduces the meshing impact between the driven gear 8 and the drive gear 9. .

  In the second embodiment, as in the case of the first embodiment, the annular groove 18 and the recessed grooves 19 are provided on the inner peripheral surface 9a of the drive gear 9. The drive gear 9 is provided on the outer peripheral surface 6a of the drive shaft 6 or the drive gear 9 is provided so as to straddle both the inner peripheral surface 9a of the drive gear 9 and the outer peripheral surface 6a of the drive shaft 6. Can be configured.

  Furthermore, the third embodiment of the present invention can be a combination of the first embodiment and the second embodiment.

  Accordingly, both the driven gear 8 and the drive gear 9 can be held so as not to be inclined with respect to the rotation axis thereof, and can be held so as not to be eccentrically deviated from the rotation center in the radial direction.

  Moreover, although each said embodiment was a case where it applied to the lubricating oil pump 4 in an internal combustion engine, it cannot be overemphasized that it can apply to the internal gear pump used for another use.

1 Cylinder block of internal combustion engine 2 Balance shaft 4 Lubricating oil pump (internal gear pump)
DESCRIPTION OF SYMBOLS 5 Pump casing 6 Drive shaft 7 Pump housing 7a Inner peripheral surface of pump housing 7b, 7c Left and right inner surface of pump housing 8 Driven gear 8a Outer surface of driven gear 8b, 8c Left and right outer surface of driven gear 9 Drive gear 9a Inner peripheral surface of drive gear 9b, 9c Left and right outer surfaces of drive gear 13 Suction port 14 Discharge port 15, 18 Annular groove 16, 19 Recessed groove 17, 20 Discharge pressure guide path

Claims (2)

An internal gear driven gear and a drive gear with an external tooth having a smaller diameter than that of the driven gear and meshing with the driven gear. The driven gear is rotatably incorporated in a pump housing in a pump casing. An intake port and a discharge port are opened on at least one of the inner surfaces on the left and right in the axial direction, and the drive gear is driven to rotate by the drive shaft, whereby the working fluid is sucked from the suction port. In the internal gear pump configured to discharge from the discharge port,
One or both of the outer peripheral surface of the driven gear and the inner peripheral surface of the pump housing are provided with an annular groove surrounding the entire outer periphery of the driven gear, while one of the outer peripheral surface of the driven gear and the inner peripheral surface of the pump housing. Or, in both of them, a concave groove extending in the axial direction is provided at a portion between the annular groove and one inner surface of the pump housing at a plurality of locations in the circumferential direction. An internal gear pump characterized in that a discharge pressure guiding path from a port to at least one of the recessed grooves is provided. An internal gear driven gear and a drive gear with an external tooth having a smaller diameter than that of the driven gear and meshing with the driven gear. The driven gear is rotatably incorporated in a pump housing in a pump casing. An intake port and a discharge port are opened on at least one of the inner surfaces on the left and right in the axial direction, and the drive gear is driven to rotate by the drive shaft, whereby the working fluid is sucked from the suction port. In the internal gear pump configured to discharge from the discharge port,
One or both of the inner peripheral surface of the drive gear and the outer peripheral surface of the drive shaft are provided with an annular groove surrounding the entire circumference of the inner peripheral surface of the drive gear, while the inner peripheral surface of the drive gear and the drive shaft In one or both of the outer peripheral surfaces, recessed grooves extending in the axial direction are provided in a portion between the annular groove and one inner surface of the pump housing at a plurality of locations in the circumferential direction, and the pump housing In addition, a discharge pressure guide path from the discharge port to at least one of the recessed grooves is provided.

Images