JP4895486B2 - Oil pump - Google Patents

Description

  The present invention relates to an oil pump. In particular, the present invention relates to an oil pump in which an oil seal is disposed between a housing in which a pump chamber is formed and a drive shaft that drives the oil pump.

  As a conventional oil pump, a housing in which an inner rotor and an outer rotor that mesh with each other are rotatably housed, a drive shaft that passes through a substantially central portion of the housing and is connected to the inner rotor, and one side portion of the housing And an oil seal that is interposed between the inner rotor and the drive shaft, and is formed along the axial direction of the drive shaft at a connecting portion between the inner rotor and the drive shaft. A drain hole whose other end opening is open to the crankcase, and a scraping member disposed at a position rearward in the rotational direction of the drive shaft with respect to the one end opening of the drain hole and having a tip facing the seal chamber. Some are provided (see, for example, Patent Document 1).

In this oil pump, oil that is about to flow into the seal chamber from the inside of the housing is forcibly collected by a collecting member provided at the end of the inner rotor and guided to the drain hole. However, the oil that is about to flow into the seal chamber from the housing is subjected to centrifugal force and leaks to the outer periphery of the collecting member, so that there is a possibility that sufficient oil cannot be collected. Moreover, since the scraping member is provided only at two places in the circumferential direction, there is a possibility that the oil that flows into the seal chamber cannot be sufficiently scraped.
Utility Model No. 2573717

  In view of this, the present invention technically prevents oil leaking from the housing from flowing into the oil seal and discharging the oil pump to prevent the oil pressure applied to the oil seal from increasing. Let it be an issue.

A first technical means for solving the above-described problem is that the housing extends in the axial direction between a housing that forms a pump chamber and an outer periphery of a drive shaft that is disposed in the pump chamber and penetrates the pump chamber. An inner rotor which is provided with a communication groove and is rotated by being engaged with the drive shaft; an outer rotor which is disposed in the pump chamber and is rotated by engaging an inner tooth with an outer tooth of the inner rotor; An oil seal disposed between the housing and the drive shaft, wherein a partition portion that partitions the pump chamber and the oil seal is formed in the housing, and the partition portion wherein the pump chamber side of, has a guide portion inclined towards the communicating groove continuous with the oil seal side of the inner wall of the cylindrical portion extending towards the inner rotor and the inner wall, the guide portion is the inner It is that it does not contact with the chromatography data.

  According to the first aspect of the present invention, the partition portion that partitions between the pump chamber and the oil seal is formed in the housing, and on the pump chamber side of the partition portion, the cylindrical portion that extends toward the inner rotor is formed. The oil leaking from the pump chamber through the gap between the cylinder portion formed in the partition portion of the housing and the inner rotor by having the inner wall and the guide portion that continues to the inner wall and inclines toward the communication groove causes the guide portion along the inner wall to leak. To flow. Further, the oil is blocked from flowing toward the oil seal by the guide portion, guided to the communication groove, and discharged through the communication groove.

  A second technical means for solving the above problem is that the guide portion is formed on the entire circumference of the inner wall.

  According to the second aspect of the present invention, since the guide portion is formed on the entire circumference of the inner wall, the oil can be guided from the entire circumference to the communication groove.

  According to the first aspect of the present invention, the oil leaking from the inside of the housing can be reliably blocked and discharged, and the pressure of the oil applied to the oil seal can be prevented from rising.

  Hereinafter, a first embodiment of an oil pump according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of an oil pump according to the present invention. This oil pump includes a housing 10 that forms a pump chamber 10p, an inner rotor 21 that is disposed in the pump chamber 10p and is driven to rotate by a crankshaft (drive shaft) 32, and external teeth 21a of the inner rotor 21 that have internal teeth. The outer rotor 22 rotated by engaging with 22a is used as a main constituent member. An oil seal 33 fixed to the housing 10 is disposed between the housing 10 and the crankshaft 32.

  The inner rotor 21 has outer teeth 21a and an inner hole 21b. Spline teeth 21c that engage with spline teeth 32a formed on the outer periphery of the crankshaft 32 are formed in the inner hole 21b. The inner rotor 21 is rotationally driven by the engagement between the spline teeth 21 c and the spline teeth 32 a of the crankshaft 32. The inner hole 21b of the inner rotor 21 does not form seven spline teeth 21c, and the rotational axis direction of the inner rotor 21 is between the outer peripheral spline teeth 32a of the crankshaft 32 that penetrates the pump chamber 10p and the inner hole 21b. A communication groove 21d extending in the direction is provided. Further, both side surfaces 21 f and 21 g of the inner rotor 21 are in sliding contact with the inner side surfaces 11 r and 12 b of the housing 10. A gap is provided between the side surface 21f and the inner side surface 11r so that oil can flow in and lubricate when both side surfaces are in sliding contact. Around the inner hole 21 b of the inner rotor 21, when the oil pump is assembled to the crankshaft 32, an annular protrusion 21 e is provided for securing the position of the inner hole 21 b of the inner rotor 21 with respect to the crankshaft 32. Yes. The protruding portion 21e may not be provided.

  The outer rotor 22 has inner teeth 22 a that sequentially mesh with the outer teeth 21 a of the inner rotor 21. A plurality of volume chambers P are formed between both teeth 21a and 22a. The outer rotor 22 is housed in a recess 11 s formed in the main body 11 of the housing 10 so as to be rotatable around a rotation center that is eccentric by a predetermined amount from the rotation center of the inner rotor 21, and is rotated by the inner rotor 21. . Here, the outer diameter of the outer periphery 22b of the outer rotor 22 is set such that a gap enough to absorb the rotational vibration of the crankshaft 32 is formed between the outer diameter of the outer rotor 22b and the inner diameter of the recess 11s of the housing 10.

  The housing 10 includes a main body 11 and a cover 12 assembled to the main body 11 and bolts 13 so as to form a pump chamber 10p. The oil pump is assembled by assembling the cover 12 to the main body 11 after assembling the inner rotor 21 and the outer rotor 22 to the main body 11 of the housing 10. The main body 11 and the cover 12 are provided with inner holes 11a and 12a through which the crankshaft (drive shaft) 32 passes. Further, as described above, the inner side surfaces 11r and 12b with which the both side surfaces 21f and 21g of the inner rotor 21 are in sliding contact are formed around the inner holes 11a and 12a, respectively.

  The main body 11 has a pump chamber 10p formed on one end side and an oil seal 33 assembled on the other end side. A partition portion 11 b that partitions the pump chamber 10 p and the oil seal 33 is formed in the main body 11. A cylindrical portion 11e extending toward the inner rotor 21 is formed on the partition portion 11b on the pump chamber 10p side. The partition portion 11b is formed with a concave portion S including an inner wall 11d of the cylindrical portion 11e and a guide portion 11c that is continuous with the inner wall 11d and is inclined toward the communication groove 21d. The guide portion 11c is formed on the entire circumference of the inner wall 11d. The recess S houses the protruding portion 21e of the inner rotor 21. Further, the axial depth of the concave portion S is set so that the end surface of the protruding portion 21e and the bottom surface of the concave portion S do not interfere when the inner rotor 21 moves in the axial direction by a distance between the side surface 21f and the inner side surface 11r. Is set.

  The body 11 has a plurality of attachments through which a reference hole (not shown) into which a positioning pin (not shown) is fitted and a mounting bolt (not shown) are inserted when assembled to an engine block (not shown). A hole 11b is provided. Further, the main body 11 is provided with a suction port 11p and a discharge port 11q.

  Next, the operation of the oil pump configured as described above will be described.

  Due to the rotation of the crankshaft 32, the inner rotor 21 fitted to the spline teeth 32a of the crankshaft 32 by the spline teeth 21c rotates together with the crankshaft 32. The outer rotor 22 meshing with the outer teeth 21 a and the inner teeth 22 a of the inner rotor 21 also rotates together with the inner rotor 21.

  By the rotation in which the inner rotor 21 and the outer rotor 22 mesh with each other, the plurality of volume chambers P formed between the teeth 21a and 22a are expanded and contracted, respectively, and the oil is sucked from the suction port 11p, and the discharge port 11q. Discharge from.

  At this time, the oil leaks from the pump chamber 10p when the main body 11 and the inner rotor 21 are in sliding contact with each other, and the oil flows and can be lubricated, that is, through the clearance between the side surfaces 21f and the inner surface 11r. The leaked oil flows out into the oil seal 33 and raises the pressure in the oil seal 33, so that oil leakage to the outside due to a decrease in the sealing performance tends to occur.

  However, a partition 11b is formed between the pump chamber 10p and the oil seal 33. Moreover, the cylinder part 11e extended toward the inner rotor 21 is formed in the pump chamber 10p side of the partition part 11b. The partition portion 11b is formed with a concave portion S including an inner wall 11d of the cylindrical portion 11e and a guide portion 11c that is continuous with the inner wall 11d and is inclined toward the communication groove 21d. For this reason, the oil leaking from the pump chamber 10p through the gap between the housing 10 and the inner rotor 21 flows to the guide portion 11c along the inner wall 11d of the recess S by centrifugal force. The oil is blocked by the guide portion 11c and blocked from flowing toward the oil seal 33, and is guided to the communication groove 21d. Furthermore, since the guide portion 11c is formed on the entire circumference of the inner wall 11d, the oil is guided from the entire circumference to the communication groove. The oil guided to the communication groove is discharged to, for example, a crankcase (not shown).

  Next, a second embodiment of the oil pump according to the present invention will be described with reference to the drawings.

  As shown in FIG. 4, the oil pump according to the second embodiment has an outer periphery composed of two surfaces 232 a opposed to the crankshaft 232, and the inner rotor 221 is externally inserted into the crankshaft 232 through its inner hole 221 b. Is in the form of In this embodiment, a communication groove 221d having a semicircular cross section is formed in the approximate center of the two surfaces 221c facing the two surfaces 232a.

It is a front view of an oil pump in a 1st embodiment of the present invention. It is AA sectional drawing of FIG. It is a principal part enlarged view in the 1st Embodiment of this invention. It is a front view which shows the communication groove | channel 221d in the 2nd Embodiment of this invention.

Explanation of symbols

10 ... housing 10p ... pump chamber 11 ... main body (housing)
11b ... partition part 11c ... guide part 11d ... inner wall 11e ... cylinder part 12 ... cover (housing)
21, 221 ... inner rotor 21 a ... outer teeth 21 d, 221 d ... communication groove 22 ... outer rotor 22 a ... inner teeth 32, 232 ... crankshaft (drive shaft)
33 ... Oil seal S ... Recess

Claims (3)

A housing forming a pump chamber;
An inner rotor which is disposed in the pump chamber and is provided with a communication groove extending in the axial direction between the outer periphery of the drive shaft passing through the pump chamber, and is driven to rotate by engaging with the drive shaft;
An outer rotor disposed in the pump chamber and rotated by engaging inner teeth with outer teeth of the inner rotor;
In an oil pump provided with an oil seal disposed between the housing and the drive shaft,
Forming a partition in the housing to partition between the pump chamber and the oil seal;
On the pump chamber side of the partition portion, there is an inner wall of a cylindrical portion extending toward the inner rotor and a guide portion that is connected to the oil seal side of the inner wall and is inclined toward the communication groove,
The oil pump according to claim 1, wherein the guide portion does not contact the inner rotor.   The oil pump according to claim 1, wherein the guide portion is formed on the entire circumference of the inner wall.   3. The oil pump according to claim 1, wherein the guide portion is separated from the inner rotor as it goes from a radially inner side to an outer side of the inner rotor.

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