JP2010159724A - Oil pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil pump preventing oil leakage between a side surface of a gear and a case. <P>SOLUTION: In the oil pump 1 that seals oil leakage by containing two gears 2, 3 meshed with each other in a case 4 for sending oil and bringing side surfaces 5, 6 of the gears 2, 3 into sliding contact with the case 4, a coating film 8 is formed on either one or both of the side surfaces 5, 6 of the gears 2, 3 and the inner surfaces 7 of the case 4 opposing to the side surfaces 5, 6 and a seal layer 9 is formed between the sides surfaces of the gears and the inner surfaces of the case 4 by grinding the coating layer 8 by the run-in rotation of the gears. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an oil pump having two gears that mesh with each other.

  Conventionally, in an engine, for example, an oil pump that feeds oil with a pair of gears that mesh with each other is used for lubrication and cooling (see, for example, Patent Document 1).

  In such an oil pump, a pair of gears are housed in close contact with the case, and the oil in the tooth tip space is sent to the discharge side by the rotation of the gears.

JP-A-9-105318

  However, since the oil pump has a gap between the side surface (axial end surface) of the gear and the case, the oil flows backward (leaks) from the discharge side to the suction side, and the efficiency of the oil pump decreases. was there.

  Therefore, an object of the present invention is to provide an oil pump that solves the above-described problems and can suppress oil leakage between the side surface of the gear and the case.

  In order to achieve the above object, according to the present invention, two meshing gears for sending oil are accommodated in a case, and the side surface of the gear is slidably contacted with the case to seal oil leakage. In the oil pump, a coating layer is formed on one or both of the side surface of the gear and the inner surface of the case facing the side surface, and the coating layer is shaved by the break-in rotation of the gear, and the side surface of the gear and the An oil pump, wherein a seal layer is formed between an inner surface of a case.

  2. The oil pump according to claim 1, wherein the coating layer is formed by applying a solid lubricant.

  In order to achieve the above object, according to the present invention, two meshing gears for sending oil are accommodated in a case, and the side surface of the gear is slidably contacted with the case to seal oil leakage. In the oil pump, a partition plate is provided between the side surface of the gear and the inner surface of the case facing the side surface, and the partition plate is disposed on the side surface of the gear between the partition plate and the inner surface of the case. An urging means for pressing and sliding is provided.

  Preferably, the urging means is an O-ring which is provided between the inner surface of the case and the partition plate and seals oil leakage between them.

  Preferably, a coating layer made of a solid lubricant is formed on one or both of the side surface of the gear and the side surface of the partition plate that is in sliding contact with the side surface.

  According to the present invention, an excellent effect that oil leakage between the side surface of the gear and the case can be suppressed is exhibited.

FIG. 1 is a schematic sectional side view of an oil pump according to a first embodiment of the present invention. FIG. 2 is a front view of the case main body of the oil pump according to the first embodiment. FIGS. 3A to 3C are views for explaining an oil pump assembling method according to the first embodiment. FIG. 4 is a schematic sectional side view of an oil pump according to the second embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
The oil pump according to the present embodiment eliminates the axial gap between the gear and the case. The oil pump is attached to an engine mounted on a vehicle, for example, and is driven by the engine to be used for sending lubricating oil to a friction portion of the engine.

  The schematic structure of the oil pump according to the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 1 and 3, the oil pump 1 houses a pair of gears 2 and 3 that are externally meshed with each other for sending oil in the case 4, and the side surfaces 5 and 6 of the gears 2 and 3 are placed in the case. 4 is slidably contacted to seal oil leakage, and a coating layer is formed on one or both of the side surfaces 5 and 6 of the gear and the inner surface 7 of the case 4 facing the side surfaces 5 and 6 of the gear. 8, and the coating layer 8 is scraped by a gear running-in rotation to form a seal layer 9 between the side surfaces 5 and 6 of the gears 2 and 3 and the inner surface 7 of the case 4.

  The case 4 includes a case body 12 in which a recess 11 (see FIGS. 2 and 3) for housing the gears 2 and 3 is formed, and a cover 13 that is attached to the case body 12 and closes the recess 11 of the case body 12. It consists of. The case main body 12 and the cover 13 in the illustrated example are bolt-bonded, and a plurality of screw holes 14 for the bolt connection are formed in the case main body 12, and through holes 15 through which the bolt passes are formed in the cover 13. The

  As shown in FIG. 2, the space (gear chamber) defined by the recess 11 and the cover 13 of the case body 12 is separated from the suction side with the meshing portion of the gears 2 and 3 accommodated therein. It is divided into the side. A suction port (not shown) that communicates with the engine oil pan is formed in the recess 11 or the cover 13 on the suction side, and a discharge port that communicates with the sliding portion and the bearing portion of the engine in the recess 11 on the discharge side. 16 is formed.

  Returning to FIGS. 1 and 3, the recess 11 is formed to have the same depth (length in the left-right direction in FIG. 1) as the width (thickness) of the gears 2 and 3. The recess 11 includes an inner surface (hereinafter referred to as a case inner peripheral surface 22) facing the tooth tips of the gears 2 and 3, and an inner surface of the case 4 (hereinafter referred to as a case inner side surface) 7 facing the side surfaces 5 and 6 of the gear. Have

  Shaft holes 23 and 24 through which a drive shaft 35 for the drive side gear 2 and a driven shaft 36 for the driven side gear 3 to be described later are inserted are formed in the inner surface 7 of the case. Similarly, shaft holes 25 and 26 through which the drive shaft 35 and the driven shaft 36 are inserted are also formed in the cover 13. In these shaft holes 25 and 26, annular bearing members (bushings) 28 for rotatably supporting the drive shaft 35 and the driven shaft 36 are respectively fitted.

  The gears 2 and 3 include a driving side gear 2 to which a rotational driving force from the engine is transmitted, and a driven side gear 3 that is rotationally driven by the driving side gear 2.

  The driving side gear 2 and the driven side gear 3 are arranged in mesh in the recess 11, one side surface (hereinafter referred to as gear side surface) 5, 6 faces the case inner side surface 7, and the other side surface 31, 32. Faces the side surface 33 of the cover 13. Further, the tooth tips of the drive side gear 2 and the driven side gear 3 are in close contact with the case inner peripheral surface 22.

  The drive side gear 2 is fixed to a drive shaft 35 rotatably supported by the case body 12 and the cover 13. A headgear 37 connected to a crankshaft of an engine (not shown) via a gear train is fixed to the drive shaft 35. Specifically, the end portion (right end portion in FIG. 1) of the drive shaft 35 penetrates the shaft hole 25 of the cover 13 and protrudes to the outside of the case 4, and the headgear 37 is fixed to the protruding end portion. The driven gear 3 is fixed to a driven shaft 36 that is rotatably supported by the case body 12 and the cover 13.

  As will be described in detail later, in the present embodiment, a seal layer 9 is formed by partially scraping the coating layer 8 on the surfaces of the gear side surfaces 5 and 6 of the drive side gear 2 and the driven side gear 3. . With the seal layer 9, the entire gear side surfaces 5 and 6 are in contact (sliding contact) with the case inner side surface 7 without a gap.

  Next, a method for assembling the oil pump 1 of the present embodiment will be described based on FIGS. 3 (a) to 3 (c).

In the present embodiment, a solid lubricant such as molybdenum (MoS ₂ ) or graphite using a resin as a binder is provided on the gear side surfaces 5 and 6 (sliding surface with the case inner side surface 7). Apply about 10 μm thicker than the gap (ie, coating thickness = gap + about 10 μm), and then, by running-in after the oil pump 1 is assembled, scrape off about 10 μm thick part of the solid lubricant, and gears 2, 3 and the case The gap with 4 is set to 0.

  First, as shown in FIG. 3 (a), a resin containing fine lubricant (diameter of about 0.1 to 2 μm) in a solid lubricant, and the resin is added to the gear side surface 5 of the drive side gear 2 and the driven side gear 3, 6 is applied and dried to form a coating layer 8 having a predetermined thickness on the gear side surfaces 5 and 6.

  Here, the thickness of the coating layer 8 is preferably 20 μm or more and less than 50 μm, more preferably 30 μm.

  This is because if the thickness of the coating layer 8 is less than 20 μm, it becomes thinner than the gap between the side surfaces 5 and 6 of the gears 2 and 3 and the inner surface 7 of the case 4, while if it is 50 μm or more, the gears 2 and 3. This is because the astringency (rotational resistance) of the gears 2 and 3 becomes large during the break-in rotation and becomes unsuitable for production.

  The solid lubricant is preferably one that does not adversely affect the solid lubricant even if it is mixed inside the engine.

  Next, as shown in FIG. 3B, the drive side gear 2 and the driven side gear 3 on which the coating layer 8 is formed are assembled to the case 4.

  Specifically, the drive-side gear 2 is shrink-fitted on the drive shaft 35 and the driven-side gear 3 is shrink-fitted on the driven shaft 36, and the gears 2 and 3 and the shafts 35 and 36 are accommodated in the recess 11 of the case body 12. A cover 13 is attached to the case body 12 and tightened with bolts.

  The bolt tightening is performed until the cover 13 comes into contact with the case main body 12 and the concave portion 11 of the case main body 12 is liquid-tightly sealed. In the bolted oil pump 1, the case main body 12, the coating layer 8, the driving gear 2, the driven gear 3, and the cover 13 are assembled with a slight deformation corresponding to the thickness of the coating layer 8. Thus, the coating layer 8 of the gear side surfaces 5 and 6 is pressed against the inner surface 7 of the case by their rigidity (repulsive force).

  After this bolting, the headgear 37 is further shrink-fitted on the drive shaft 35.

  Next, as shown in FIG. 3C, the driving side gear 2 and the driven side gear 3 assembled to the case 4 are acclimated and rotated.

  The break-in rotation is performed by rotating the headgear 37 in a state where there is no oil in the recess 11 (that is, a state where the oil pump 1 does not work). For example, before assembling the oil pump 1 to the engine, the headgear 37 is rotated with a tool or the like alone.

  When the headgear 37 is rotated, the driving side gear 2 and the driven side gear 3 are rotated, and the coating layer 8 of the gears 2 and 3 slides with respect to the inner surface 7 of the case. At this time, since the coating layer 8 is pressed against the inner surface 7 of the case as described above, a frictional force acts on the coating layer 8.

  By this running-in rotation, the coating layer 8 of the driving side gear 2 and the driven side gear 3 is scraped off. The coating layer 8 to be scraped off increases as the distance between the gear side surfaces 5 and 6 (not including the coating layer 8) and the case inner side surface 7 is narrower.

  The running-in rotation described above is performed until the driving side gear 2 and the driven side gear 3 rotate smoothly. That is, when the headgear 37 is rotated, the torque necessary for the rotation decreases as the coating layer 8 is scraped off. For example, the torque is measured, and the measured torque becomes a predetermined value or less. Until the headgear 37 is rotated.

  As a result, a seal layer 9 for sealing oil leakage is formed between the gear side surfaces 5 and 6 and the case inner side surface 7, and the seal layer 9 (gear side surfaces 5 and 6) and the case inner side surface 7 The gap becomes zero. At the same time, the gap between the side surfaces 31 and 32 of the gear facing the cover 13 (the right side surface in FIG. 1) and the side surface 33 of the cover 13 is also zero.

  Next, the operation of the oil pump 1 of the present embodiment will be described.

  When the oil pump 1 is operated, the driving side gear 2 and the driven side gear 3 are rotated by the rotational driving force from the engine. By the teeth of the rotating drive gear 2 and driven gear 3, the oil on the suction side in the recess 11 is sent to the discharge side along the case inner peripheral surface 22. The oil sent to the discharge side is sent out from the discharge port 16 by the engagement of the drive side gear 2 and the driven side gear 3. At this time, the pressure of the oil on the discharge side is higher than that on the suction side, causing a pressure difference.

  Here, in this embodiment, since the gap between the gear side surfaces 5 and 6 and the case inner side surface 7 is 0, even if a pressure difference occurs, the gap between the gear side surfaces 5 and 6 and the case inner side surface 7 is reduced. The oil does not flow backwards through.

  Thus, according to the oil pump 1 of this embodiment, the internal leakage of the oil pump 1 is reduced and the pump efficiency is increased by setting the clearance between the gear side surfaces 5 and 6 and the case inner side surface 7 to be substantially zero. be able to.

  Thereby, if it is the oil pump 1 of the same discharge amount, a pump drive force can be lowered | hung and it can improve the fuel consumption of an engine.

  In addition, the loss due to friction can be reduced by forming the coating layer 8 from a solid lubricant.

(Second Embodiment)
Next, a second embodiment will be described based on FIG.

  This embodiment is different from the first embodiment described above in that a seal layer 9 is not provided between the gear side surfaces 5 and 6 and the case inner side surface 7, a partition plate described later instead of the seal layer 9, and The main difference is that an urging means is provided, and the rest of the structure is almost the same. Therefore, the same elements as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 4, the oil pump 40 of the present embodiment includes a partition plate 41 between the gears 2 and 3 and the case 4, and uses an elastic body 42 such as rubber or a spring or a repulsive force of a magnet as a biasing force. Then, the partition plate 41 is pressed against the gears 2 and 3.

  Here, in any case of using any urging force, it is necessary to prevent (seal) oil leakage to the back side of the partition plate 41 using the O-ring 42. As will be described later in detail, the O-ring 42 can have both the sealing function and the elastic function.

  More specifically, the partition plate 41 is provided between the gear side surfaces 5 and 6 and the case inner side surface 7. The partition plate 41 has substantially the same shape as the case inner side surface 7 and is formed slightly smaller than the case inner side surface 7 so as to be disposed in the recess 11. The partition plate 41 is formed with through holes 43 and 43 through which the drive shaft 35 and the driven shaft 36 pass, and a seal member (not shown) is provided in each through hole. Due to the partition plate 41, the case body 12 has a doubled inner surface facing the drive side gear 2 and the driven side gear 3.

  An O-ring 42 is provided between the partition plate 41 and the case inner side surface 7. The O-ring 42 prevents the oil in the recess 11 from entering between the case inner side surface 7 and the partition plate 41 and keeps the case inner side surface 7 and the partition plate 41 fluid-tight. Yes, it is formed in a shape along the edge (contour) of the partition plate 41 (and the case inner side surface 7).

  The O-ring 42 serves as an urging means for urging the partition plate 41 toward the gear side surfaces 5 and 6 and pressing the partition plate 41 against the gear side surfaces 5 and 6 to make sliding contact. That is, the O-ring 42 is disposed in a compressed state between the partition plate 41 and the case inner side surface 7, and presses the partition plate 41 toward the gear side surfaces 5 and 6 by its elastic restoring force.

  When the O-ring 42 presses the partition plate 41 against the gear side surfaces 5 and 6 in this way, friction is generated between the partition plate 41 and the gear side surfaces 5 and 6. Therefore, in the present embodiment, in order to reduce friction, solid lubricant application or DLC is applied to one or both of the gear side surfaces 5 and 6 and the side surface of the partition plate 41 that is in sliding contact with the gear side surfaces 5 and 6. Surface treatment such as (diamond-like carbon film formation), PVD, WPC (shot peening) or the like is performed.

  Also in the present embodiment, oil leakage between the side surfaces 5 and 6 of the gears 2 and 3 and the case 4 can be suppressed as in the above-described embodiment.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, the oil pump 1 of the above-described embodiment is a gear pump in which a pair of gears are externally meshed with each other. However, the present invention is not limited to this, and other types such as a trochoid pump provided with an internal gear and an external gear. It can also be used with other types of pumps.

  In the first embodiment, the coating layer 8 is formed only on the gear side surfaces 5 and 6. However, the present invention is not limited to this, and only the case inner side surface 7 or both the gear side surfaces 5 and 6 and the case inner side surface 7 are formed. A coating layer may be formed, and it is conceivable to form the sealing layer 9 between the side surfaces 31 and 32 of the gear and the side surface 33 of the cover 13.

  In the second embodiment, the urging means is an O-ring, but is not limited to this.

1 Oil pump 2, 3 Gear 4 Case 5, 6 Side (Gear side)
7 Inner surface (inner side surface)
8 Coating layer 9 Sealing layer 41 Partition plate 42 O-ring (biasing means)

Claims (5)

In the oil pump in which two gears that mesh with each other for sending oil are accommodated in the case, and the side of the gear is in sliding contact with the case to seal oil leakage,
A coating layer is formed on one or both of the side surface of the gear and the inner surface of the case opposite to the side surface, and the coating layer is shaved by running-in rotation of the gear, and the side surface of the gear and the inner surface of the case An oil pump characterized in that a seal layer is formed between the two.   The oil pump according to claim 1, wherein the coating layer is formed by applying a solid lubricant. In the oil pump in which two gears that mesh with each other for sending oil are accommodated in the case, and the side of the gear is in sliding contact with the case to seal oil leakage,
A partition plate is provided between the side surface of the gear and the inner surface of the case facing the side surface, and the partition plate is pressed against the side surface of the gear between the partition plate and the inner surface of the case. An oil pump characterized in that an urging means is provided.   4. The oil pump according to claim 3, wherein the biasing means is an O-ring that is provided between the inner surface of the case and the partition plate and seals oil leakage between them.   The oil pump according to claim 3, wherein a coating layer made of a solid lubricant is formed on one or both of a side surface of the gear and a side surface of the partition plate that is in sliding contact with the side surface.

Images