JP5812722B2 - Structure of lubricating device for internal combustion engine - Google Patents

Description

  The present invention relates to a structure of a lubrication device provided with an oil pump at the end of a crankshaft or balance shaft that is rotatably supported by a rolling bearing in a crank chamber of an engine.

  In an internal combustion engine, there are many portions that slide mechanically, and various lubrication mechanisms are provided to reduce friction and wear. The main method is a method of supplying lubricating oil to a portion requiring lubrication. Because of this lubrication mechanism, the internal combustion engine is equipped with an oil pump.

  As the oil pump, a trochoid oil pump is often used. In this oil pump, an inner rotor having a convex portion that is one less than the number of concave portions of the outer rotor is arranged inside the outer rotor having a concave portion formed by a trochoid curve, and the tip of the convex portion of the inner rotor slides on the inner wall of the concave portion of the outer rotor. As it rotates, it sucks and discharges oil.

  This inner rotor uses the rotation of the crankshaft or balance shaft as driving power. Therefore, it is preferable that the inner rotor has a structure fixed to the end portions of these shafts.

  The crankshaft and balance shaft are pivotally supported by the crank chamber with rolling bearings and rotate at high speed. It is therefore necessary to lubricate the rolling bearings that pivot these shafts.

  Patent Document 1 discloses a structure in which a bearing that pivotally supports a balance shaft is lubricated by an internal combustion engine in which an inner rotor is directly connected to an end portion of the balance shaft. Here, an oil passage is formed from the oil pump through the balance shaft to a position pivotally supported by the bearing. That is, oil is supplied to the bearing through a passage in the balance shaft.

  Patent Document 2 discloses a technique for further supplying oil supplied from an oil pump to a gear chamber to a bearing of a balance shaft via an oil hose.

JP 2006-200409 A JP 07-217703 A

  The lubricating structure of Patent Document 1 is considered to be a structure that can sufficiently lubricate the bearing portion of the shaft. However, an oil passage must be formed in the balance shaft. This makes it difficult to process the balance shaft, leading to an increase in cost.

  The method of Patent Document 2 can simplify the lubrication structure in that it is not necessary to dispose an oil passage for each lubrication location. However, since oil is fed from one lubrication location to another lubrication location, a large pressure is required at the oil feed source. This leads to an increase in the size of the pump, and causes a problem that fuel consumption deteriorates due to mechanical loss related to oil feeding between lubrication points.

  The present invention has been conceived in view of the above-described problems, and lubricates a bearing that pivotally supports a crankshaft or a balance shaft, to which an oil pump is connected to an end portion, without using an oil passage or oil feed hydraulic pressure. The structure of a lubricating device for an internal combustion engine is provided.

More specifically, the structure of the lubricating device for an internal combustion engine of the present invention is as follows:
A structure of a lubricating device for an internal combustion engine comprising a crankshaft mounted in a crank chamber of an engine via a rolling bearing or a drive shaft for driving an oil pump at an end of a balance shaft,
The rotor of the oil pump is disposed adjacent to the rolling bearing through the body of the oil pump,
Said body includes a through hole for the drive shaft for rotating the rotor is inserted, so as to abut against the outer race of the front Symbol rolling bearing of the bearing to the rolling bearing side in the gravity below the through-hole With protruding protrusions ,
Oil flowing out from a gap between the drive shaft and the through hole flows to the rolling bearing through the protrusion .

  In the structure of the lubricating device for an internal combustion engine according to the present invention, a projecting portion projecting toward the rolling bearing is provided on the body of the oil pump disposed adjacent to the rolling bearing, and the projecting portion is an outer race of the rolling bearing. Therefore, when the oil pump is attached to the engine, the protruding portion causes the rolling bearing to be pressed and fixed into the mounting hole of the rolling bearing. Therefore, a member such as a snap ring for fixing the rolling bearing is not necessary, which contributes to cost reduction.

  Further, since oil leaking from the clearance between the oil pump and the shaft shaft is supplied to the rolling bearing through the protruding portion, the rolling bearing can be lubricated without using any special supply means. That is, it is not necessary to form a separate oil supply passage for the rolling bearing, and there is no need to supply pressure for sending oil. Therefore, the fuel efficiency can be improved without increasing the size of the oil pump and generating a load such as mechanical loss.

It is sectional drawing which shows the structure of the lubricating device of this invention. It is a figure which illustrates the external appearance of the oil pump which concerns on the structure of the lubricating device of this invention. It is a figure which illustrates the external appearance of the other oil pump which concerns on the structure of the lubricating device of this invention.

  The structure of a lubricating device for an internal combustion engine of the present invention (hereinafter simply referred to as “the structure of a lubricating device”) will be described below with reference to the drawings. The following description exemplifies an embodiment of the present invention, and changes within the scope of the present invention are included in the technical scope of the present invention without departing from the spirit of the present invention. Needless to say.

  FIG. 1 is a sectional view showing a state in which an oil pump 10 constituting a structure 1 of a lubricating device according to the present invention is attached to a balance shaft 3. Although the case where the oil pump 10 is attached to the balance shaft 3 is shown in the present embodiment, the oil pump 10 may be attached to a crankshaft (not shown). The balance shaft 3 is a shaft that is disposed in parallel with the crankshaft and has an unbalanced weight that rotates in synchronization with the crankshaft. By rotating, it generates vibration and cancels the vibration generated by the piston (not shown).

  The balance shaft 3 is supported using a balance shaft mounting hole 4 provided in the cylinder block 2. Since the balance shaft 3 is assumed to rotate, it must be supported rotatably. Therefore, a rolling bearing 20 is disposed in the balance shaft mounting hole 4. A pivot shaft 3 c is formed at the end of the balance shaft 3 to be fitted to the inner diameter surface 21 i of the inner race 21 of the rolling bearing 20.

  The cylinder block 2 has a through-hole formed in the outer wall surface 2 f having a diameter larger than that of the pivot shaft 3 c of the balance shaft 3 and smaller than the diameter of the outer race 23 of the rolling bearing 20. This through hole is the balance shaft mounting hole 4. Further, a step 4 s is provided around the balance shaft mounting hole 4. That is, a recess having a through hole is formed in the middle from the outer wall surface 2 f of the cylinder block 2. The rolling bearing 20 is fitted into the recess formed by the step 4s from the outer wall surface 2f side of the cylinder block 2.

  The pivot shaft 3c of the balance shaft 3 is inserted and fixed from the inside of the cylinder block 2 to the inner race 21 of the rolling bearing 20 fitted in the recess.

  The rolling bearing 20 includes an inner race 21, a bearing 22, and an outer race 23. The inner race 21 and the outer race 23 are ring members having different diameters, and a predetermined number of bearings 22 are fitted and held between the inner race 21 and the outer race 23. Since the inner race 21 and the outer race 23 are in contact with the bearing 22, their rotational movements interfere only with the sliding resistance of the bearing 22 with respect to the other.

  That is, in the rolling bearing 20, the bearing sliding portion is between the inner race 21 and the bearing 22 and between the bearing 22 and the outer race 23. Each sliding part was made into 25i and 25o. Further, when both sliding portions are described together, they are simply referred to as “sliding portion 25”. Here, the outer race 23 is fixed to the cylinder block 2, and the balance shaft 3 inserted and fixed to the inner race 21 is pivotally supported.

  A drive shaft 3 d of the oil pump 10 is formed at the further tip of the pivot shaft 3 c of the balance shaft 3. The drive shaft 3 d of the oil pump 10 has a shape that fits into the rotation center of the inner rotor 12 of the oil pump 10. This is for driving the oil pump 10. The shape of the drive shaft 3d is not particularly limited, but is preferably a polygonal column such as a triangular column, a quadrangular column, or a hexagonal column. This is because processing is easy and the rotational torque of the balance shaft 3 can be reliably transmitted to the oil pump 10.

  On the other hand, the oil pump 10 is preferably a trochoid oil pump. This is because the thickness is thin and the suction pressure / discharge pressure is high. The oil pump 10 includes a housing 11, an outer rotor 16, an inner rotor 12 disposed inside the outer rotor 16, and a body 13 for creating a closed space between the housing 11. Here, the body 13 is a donut-shaped flat member that is in close contact with the periphery of the housing 11 and exposes the center of rotation of the inner rotor 12. The oil pump 10 has a suction port and a discharge port as a whole, but the positions thereof are not particularly limited.

  Furthermore, in the structure 1 of the lubricating device of the present invention, the oil pump 10 has a protruding portion 14 protruding from the surface of the body 13. The protrusion 14 is provided so as to face the rolling bearing 20 when the oil pump 10 is attached to the drive shaft 3 d of the balance shaft 3 and fastened to the cylinder block 2.

  In FIG. 2, the external appearance of the oil pump 10 is shown. The outer side is covered with a housing 11, and an outer rotor 16 is disposed therein, and an inner wall of the outer rotor 16 is formed in a trochoid shape. Around the housing 11, a bracket 11b with a through hole for fastening and fixing is formed. The body 13 also serves as a lid of the housing 11 and prevents the oil to be sucked / discharged from leaking outside by rotating the inner rotor 12 inside.

  A through hole 13h for inserting a drive shaft 3d for driving the inner rotor 12 is formed in the middle. In FIG. 2, a recess having a hexagonal cross section is formed at the center of the body 13. This is the rotating shaft 12 c of the inner rotor 12. Further, a protruding portion 14 is formed at a predetermined position from the through hole 13h of the body 13 to the peripheral edge 11e.

  Although the shape of the protrusion part 14 is not specifically limited, It is preferable that the front-end | tip 14t is flat. This is because the tip 14t of the projecting portion 14 is brought into contact with the rolling bearing 20, and if the tip 14t is sharp, the rolling bearing 20 may be damaged. Moreover, you may have shapes other than column shape so that it may mention later.

  Returning to FIG. 1 again, the drive shaft 3d is inserted into and fitted to the recessed rotating shaft 12c at the center of the body 13, and the periphery of the housing 11 is fastened and fixed to the cylinder block 2 with bolts or the like. At this time, the tip 14 t of the protrusion 14 is in contact with the outer race 23 of the rolling bearing 20 so as to push it from the outside of the cylinder block 2. This state can be said to be a state in which the rotor (16 or 12) of the oil pump 10 is disposed adjacent to the rolling bearing 20 that pivotally supports the balance shaft 3 via the body 13 of the oil pump 10.

  When the engine is driven in such a state, the balance shaft 3 starts rotating, and the oil pump 10 also starts to be driven by the drive shaft 3d provided on the extension of the balance shaft 3. Then, oil leaks from the gap 15 between the through hole 13 h of the body 13 and the drive shaft 3 d of the balance shaft 3. This oil falls almost downward under gravity and hits the protrusion 14.

  For oil having a large surface tension, the protruding portion 14 serves as a bridge connecting the oil pump 10 and the rolling bearing 20. That is, oil is transmitted to the rolling bearing side 20 through the protrusion 14. Then, the oil is supplied to the rolling bearing 20 through the outer race 23 of the rolling bearing 20 and lubricated.

  The sliding portion 25 of the rolling bearing 20 is 25 o between the outer race 23 and the bearing 22 and 25 i between the inner race 21 and the bearing 22. However, if the oil reaches the outer race 23, the oil penetrates into the space 25o between the outer race 23 and the bearing 22 due to surface tension or the like, and the penetrated oil reaches the space 25i between the bearing 22 and the inner race 21.

  In other words, in the structure 1 of the lubricating device according to the present invention, the protrusion 14 formed on the surface of the body 13 is formed below the gravity from the recess for insertion fitting of the drive shaft 3d at the center of the body 13 (center of the rotating shaft 12c of the inner rotor 12). It is preferable to do this. The position to be formed is a position away from the center of the rotating shaft 12 c of the inner rotor 12 by a predetermined distance, and the “predetermined distance” is a position where the outer race 23 of the rolling bearing 20 can be contacted.

  Further, FIG. 3 shows an oil pump 10 having other shape variations of the protrusion 14. Referring to FIG. 3, the protrusion 14a has an arc shape when viewed from the front. Alternatively, it may be annular. As shown in FIG. 3, when the arcuate protrusion 14a is formed on the body 13, oil leaking from the gap 15 between the drive shaft 3d and the body 13 accumulates in the arcuate arc portion 14b. Can be supplied.

  As described above, in the structure 1 of the lubricating device according to the present invention, the oil pump 10 is fixed adjacent to the rolling bearing 20 and has the protruding portion 14 protruding from the body 13 toward the rolling bearing 20. The rolling bearing 20 can be fixed without a fixing member. Further, since the oil is transmitted through the projecting portion 14 and is also lubricated to the sliding portion 25 of the rolling bearing 20, there is no need to separately provide oil feeding means, and it is not necessary to prepare pressure for oil feeding. This can contribute to cost and low fuel consumption.

  The present invention can be suitably used for an internal combustion engine having an oil pump arranged adjacent to a rolling bearing that pivotally supports a crankshaft or a balance shaft.

DESCRIPTION OF SYMBOLS 1 Lubricator structure 2 Cylinder block 2f Outer wall surface 3 Balance shaft 3c Pivot shaft 3d Drive shaft 10 Oil pump 11 Housing 11b Bracket 11e Periphery 12 Inner rotor 12c Rotating shaft of inner rotor 13 Body 13h Through hole 14 Protruding portion 14a Other shapes Projection 14b Arc-shaped arc portion 14t (projection) tip 15 Clearance 16 Outer rotor 20 Rolling bearing 21 Inner race 21i Inner race inner diameter surface 22 Bearing 23 Outer race 25, 25i, 25o Sliding portion

Claims (1)

A structure of a lubricating device for an internal combustion engine comprising a crankshaft mounted in a crank chamber of an engine via a rolling bearing or a drive shaft for driving an oil pump at an end of a balance shaft,
The rotor of the oil pump is disposed adjacent to the rolling bearing through the body of the oil pump,
Said body includes a through hole for the drive shaft for rotating the rotor is inserted, so as to abut against the outer race of the front Symbol rolling bearing of the bearing to the rolling bearing side in the gravity below the through-hole With protruding protrusions ,
A structure of a lubricating device for an internal combustion engine, wherein oil flowing out from a gap between the drive shaft and the through hole flows to the rolling bearing through the protruding portion .