JP6482109B2 - Internal combustion engine - Google Patents

Description

The present invention, which relates to an internal combustion agencies, Ru Tei the car dual internal combustion engine to a suitable target.

  A crankshaft of the internal combustion engine protrudes on both sides of the engine body, and a rotating body such as a flywheel or a crank pulley is fixed to the protruding end. The crankshaft is rotatably held by a bearing of the cylinder block, but an oil seal is disposed outside the bearing portion in order to prevent oil leakage. The oil seal is intended to prevent the oil from leaking outside from the bearing, but it has the property that it is difficult to suppress the intrusion of water from the outside (the viscosity of oil is different from that of water. Even if it can be sealed, water cannot be reliably sealed.) Moreover, if dust or sand mixed in water bites into the oil seal, the seal portion may be damaged and damaged.

  Therefore, for example, in the case of an internal combustion engine for a vehicle, when the lower part of the internal combustion engine is immersed in water by traveling on a road where the vehicle is submerged, the outer surface of the oil seal is immersed in water. There is a problem that it is easy to enter the crank chamber.

  With regard to this point, for example, as described in Patent Document 1, it is conceivable to provide a water sealing material on the oil seal, but in this configuration, the frictional resistance between the oil seal and the crankshaft is low. There is a problem of increasing. On the other hand, Patent Document 2 discloses that a non-contact dust seal is formed by fixing a magnetic encoder to the inner surface of a flywheel and narrowing the interval between the magnetic encoder and the sensor.

CD-ROM of Japanese Utility Model Publication No. 5-45334 JP 2006-46097 A

Application but dust seal in Patent Document 2 is not increased frictional resistance because non-contact type, can not be applied to an internal combustion engine having no magnetic encoder, also, even if that is not available in a state where the magnetic encoder is bought immersion in water There is a problem that it cannot be done and lacks generality.

  The present invention has been made to improve the current situation.

The internal combustion engine of the present invention is
“One end of the crankshaft is exposed outside the engine body, and a flywheel or other rotating body positioned outside the engine body is fixed to one end of the crankshaft, and the outer periphery of the crankshaft has established an oil seal between the engine body and,
Furthermore, an annular water seal portion with a narrow gap that prevents water from entering from a radially outer side to a portion radially outside the outer periphery of the oil seal among the portions where the engine body and the rotating body face each other. It is formed in one piece. ''
This is the basic configuration.

And, the invention of claim 1 is the above basic configuration,
“The engine body has a cylinder block with a crank chamber opened downward, and an oil pan with an upward opening fixed to the lower surface of the cylinder block. The main body side water sealing ribs constituting the water sealing portion are formed approximately half a circumference, and the width dimension of the main body side water sealing rib provided in the oil pan is the width dimension of the main body side water sealing rib provided in the cylinder block. While being bigger than
The rotating body includes a rotating body side water sealing rib having a width dimension substantially equal to or larger than the width dimension of the main body side water sealing rib provided on the oil pan, and the main body side water of the cylinder block and the oil pan. It is formed to face the sealing rib. ''
It is the composition.

According to a second aspect of the present invention, in the basic configuration,
“When the clearance dimension of the annular water seal portion is ymm, the overlap size of the annular water seal portion viewed from the crank axis direction is xmm, and the natural logarithm is Ln, y and x are y = −0. .0179x2 + 0.4773x and an approximation satisfying y = 1.018Ln (x) -0.9239 .
It has a rotation range of 1100-1800 rpm "
It is the composition.

In the present invention , even if the lower part of the engine body is immersed in water due to the flooding of the road or the like, it is possible to prevent or remarkably suppress water from entering the oil seal due to the presence of the annular water seal. That is, by the rotation of the rotating body, an air barrier layer is formed at the location of the annular water seal portion, preventing water from entering the inside of the annular water seal portion, or at the location of the annular water seal portion on the rotating body. The water can be blown outward to prevent water from entering, or even if water enters the radius inside the annular water seal, it can be removed by centrifugal force due to the rotation of the rotating body. Thus, it is possible to prevent or remarkably reduce the entry of water into the oil seal.

  And since the annular water sealing part is provided integrally with the engine body or the rotating body, it can be applied to various internal combustion engines and has excellent versatility, and there is no problem such as dropping off of the member, and durability is also improved. Are better.

Moreover, in this invention, since the rib for attaching an oil seal can be combined with the formation member of an annular water seal part, a structure can be simplified that much. In addition, in a normal operation state that is not immersed in water, the oil seal holding rib is cooled by the air flow generated by the rotation of the rotating body, so heat radiation from the oil seal can be promoted and the durability of the oil seal can be improved. .

  The effect of the annular water seal increases as the width increases, but if the width is large over the entire circumference, the sealing performance becomes too high and a negative pressure effect is generated by the rotation of the rotating body. There is a possibility that. Also, there is a risk that heat will be trapped during normal times. Furthermore, there is a concern that the water discharge performance will deteriorate. On the other hand, when the engine body is soaked in water, the water level rises from the bottom to the top, so the opportunity to soak in water becomes higher at the bottom of the oil pan.

And when the structure of Claim 1 is employ | adopted, in the location of an oil pan with many opportunities to soak in water, since the annular water seal part is wide, it is excellent in the water intrusion prevention function, and in the location of a cylinder block, Since the width of the annular water seal portion is narrow, it is possible to prevent or suppress the entry of water without generating a negative pressure, and it is excellent in the function of removing the entered water, and the sealing performance becomes excessive. Therefore, heat buildup can be prevented and heat dissipation of the oil seal can be secured. Moreover, since the rib of a cylinder block is thin, an increase in weight can also be suppressed.

  The narrower the gap between the annular water seals, the more difficult it is for water to enter, and the larger the overlap size of the annular water seals, the less likely it is for water to enter. It has been found that the tendency of the penetration of the ring and the gap size of the annular water seal portion does not always show a constant tendency, but the tendency changes depending on the number of rotations. That is, in the rotation region (medium rotation region) such as 1800 rpm, the amount of water intrusion is proportional to the gap size, but in the rotation region (low rotation region) such as 1100 rpm, the amount of water penetration decreases as the gap widens (gap size). (Inversely proportional).

Claim 2 is based on such research results. Based on the relational expression as in Claim 2 , the relationship between the gap dimension and the overlap dimension is set so that it falls within the fee formula. In each rotation region, water intrusion can be minimized. In reality, the gap size is preferably about 1.0 to 2.0 mm because of the limitation of the processing error of the member.

It is a longitudinal cross-sectional view of the principal part of 1st Embodiment. (A) is the elements on larger scale of FIG. 1, (B) is the elements on larger scale of (A). (A) is a separated sectional view of an engine body, and (B) and (C) are sectional views of a flywheel as an example of a rotating body. FIG. 4 is an IV-IV view of FIG. 3 in a state where an oil pan is fixed to a cylinder block. It is a graph which shows the relationship between each element and the penetration | invasion amount of water. It is the graph which displayed the approximate expression derived | led-out from the result of FIG. It is a figure which shows other embodiment and a reference example .

(1) Structure of First Embodiment Next, an embodiment of the present invention will be described based on the drawings. This embodiment is applied to a vehicle internal combustion engine. The internal combustion engine includes a cylinder block 2 and an oil pan 3 fixed to the lower surface thereof as components of the engine body 1. The cylinder block 2 and the oil pan 3 are cast products made of a metal such as aluminum. However, the oil pan 3 can be a sheet metal processed product or a resin molded product. .

  A crankshaft 4 is disposed in the crank chamber of the cylinder block 2. The crankshaft 4 includes a crank arm 5 and a crankpin 6, and a main journal (end journal) 7 and an intermediate journal 8 are connected to a bearing portion 9 provided in the cylinder block 2 via a metal bearing 10 and a crank cap 11. It is held rotatably.

One end portion 12 of the crankshaft 4 is exposed to the outside of the cylinder block 2, and the one end portion 12 is formed to have a larger diameter than the main journal 7, and a flywheel as an example of a rotating body is formed on the outer end surface thereof. 13 is fixed with a bolt 14. A positioning cylinder portion 15 that is fitted to the flywheel 13 is integrally formed at one end portion 12 of the crankshaft 4.

  An oil seal 16 is slidably fitted to one end portion 12 of the large diameter of the crankshaft 4. The oil seal 16 includes an upper oil seal holding rib 17 provided integrally with the cylinder block 2, and an oil pan 3. And a lower oil seal holding rib 18 provided integrally therewith from the outside. That is, the oil seal 16 is held by the upper and lower oil seal holding ribs 17 and 18 so as not to rotate.

In the present embodiment, the upper and lower oil seal holding ribs 17 and 18 are also used as main body side water sealing ribs constituting the annular water sealing portion. 18 and opposing site, by Rukoto provided integrally with the ring-shaped rotary section water seal rib 19 protruding toward the upper and lower oil seal retaining rib 17, the end faces of the top and bottom oil seal retaining rib 17, 18 and A space sandwiched between the end surfaces of the rotor-side water sealing ribs 19 forms an annular water sealing portion 20.

  The end faces of the oil seal holding ribs 17 and 18 are substantially coincident with the end face of the oil seal 16, and the clearance E1 between the oil seal holding ribs 17 and 18 and the rotating body side water sealing rib 19 is set to about 2 mm. Yes.

  The width dimension W1 of the upper oil seal holding rib 17 is set to about 3 to 4 mm, while the width dimension W2 of the lower oil seal holding rib 18 is set to about 6 mm. The width dimension W2 of 18 is about twice the width dimension W1 of the upper oil seal holding rib 17. The lower oil seal holding rib 18 may have an equal width over the entire length, or the width dimension of both ends so that the upper end has the same width dimension as the upper oil seal holding rib 17 as shown by a dashed line in FIG. May be gradually reduced.

  On the other hand, the width dimension W3 of the rotor-side water sealing rib 19 may be set to the same level as the width dimension W1 of the upper oil seal holding rib 17, as shown in FIGS. As shown in FIG. 3C, the width dimension W2 of the lower oil seal holding rib 18 may be set to the same level. Alternatively, it may be set to an intermediate dimension (for example, about 4.5 mm) between the width dimension W1 of the upper oil seal holding rib 17 and the width dimension W2 of the lower oil seal holding rib 18.

  As shown in FIG. 1, an annular recess 21 that opens toward the engine body 1 is formed in a portion of the flywheel 13 that is radially outward from the rotor-side water sealing rib 19. For this reason, the outer side of the annular recess 21 is constituted by an annular protrusion 22 protruding toward the engine body 1. The gap interval E2 between the annular protrusion 22 and the oil pan 3 is as small as, for example, about 3 to 4 mm, while the gap interval E3 between the annular protrusion 22 and the cylinder block 2 is, for example, 10 mm. It is a large size of about or more.

(2) Description of FIG. 5 In FIG. 5, the upper and lower oil seal holding ribs 17 and 18 and the rotating body side water are related to the amount of water entering the engine from the oil seal 16 in a state where substantially the entire oil pan 3 is submerged. The overlap dimension in the width direction with the sealing rib 19 (the overlapping dimension in the radial direction when viewed from the crank axis direction) , the engine speed, and the upper and lower oil seal holding ribs 17 and 18 and the rotating body side water sealing rib 19 The gap dimension (E1) is a variable, and the relationship between these variables and the amount of water intrusion is shown. The measurement time was 5 minutes. The water level was up to the axis of the crankshaft 4.

  In FIG. 5, curves A to C are 1800 revolutions, A is W1 = 4 mm, W2 = 6 mm, W3 = 3.5 mm, B is W1, W2, and W3 are all 6 mm, and C is W1 , W2 and W3 were both 10 mm.

  In FIG. 5, curves D to F are 1100 revolutions, D is W1 = 4 mm, W2 = 6 mm, W3 = 3.5 mm, B is W1, W2, and W3 are all 6 mm, and C is W1 , W2 and W3 were both 10 mm.

  From this figure, at 1800 revolutions, the amount of water penetration decreases as the gap dimension E1 decreases, and the amount of water penetration increases as the overlap amount between the lower oil seal holding rib 18 and the rotor-side water sealing rib 19 increases. It turns out that there are few. On the other hand, at 1100 revolutions, if W1, W2, and W3 are small (or the overlap dimension is small), the amount of water penetration is proportional to the gap dimension, but W1, W2, and W3 (or overlap dimension) are 6 mm or more. When it is large, it can be understood that the amount of water entering tends to be inversely proportional to the gap size.

  The reason why the amount of water intrusion is inversely proportional to the gap size is not always clear, but it is assumed that the centrifugal force is small when the number of revolutions is low, so that it is difficult for water to be discharged due to the viscosity (surface tension) of water. The

  In any case, since the upper and lower oil seal holding ribs 17 and 18 on the engine body 1 side and the rotating body side water sealing rib 19 of the flywheel 13 are formed with the annular water sealing portion 20 having a small gap, Even in the operation at, the intrusion of water into the bearing and the crank chamber via the oil seal 16 can be greatly suppressed.

  In the present embodiment, the distance E2 between the annular protrusion 22 of the flywheel 13 and the end face of the oil pan 3 is as small as several millimeters, so that the function of preventing water from entering the oil seal 16 is further enhanced. Moreover, since the space | interval dimension E3 between the cyclic | annular protrusion 22 of the flywheel 13 and the cylinder block 2 is about 10 mm, while being excellent in the splashing function of water, the cloudiness of the heat | fever at the time of normal driving | operation can also be prevented.

(3). Description of FIG. 6 Generally, it can be said that there is no practical problem if the intrusion amount is 0.15 grams or less in about 5 minutes at 1800 revolutions. Accordingly, in the curves A to C in FIG. 5, when the gap dimensions A ′, B ′, and C ′ that achieve the allowable value of 0.15 gram are seen, A ′ = 1.26 mm, B ′ = 2.4 mm, C ′ = 2.94 mm. In FIG. 6, the vertical axis is the gap size and the horizontal axis is the overlap size. A ′, B ′, and C ′ are plotted, and these polynomial approximation curves are drawn as curve G. Met.

  When the gap dimension is ymm and the overlap dimension is xmm, the curve G is expressed by an approximate expression of y = -0.0179x2 + 0.4773x (R2 = 0.9517). Therefore, y is an increasing function of x, and the increasing rate of y tends to decrease with respect to the increasing rate of x.

  At 1100 revolutions, 0.05 g or less is set as an allowable value, and the gap D of curve D that satisfies this allowable value is less than 1.0 mm, and the corresponding gap E of curve E is 0.90 mm. Yes, the corresponding gap dimension F ′ of the curve F was 1.42 mm. In FIG. 6, E ′ and F ′ are plotted, and an approximate expression (approximate curve) of H is obtained by a logarithmic approximation method. That is, the approximate expression of H was obtained by using data (results of curves E and F in FIG. 5) of the result that the gap size and the water penetration amount are inversely proportional. This approximate expression is expressed by y = 1.018Ln (x) -0.9239 (R2 = 1.0). Ln is a natural logarithm.

  In the curve H, y is an increasing function of x, and in order to obtain the same water sealing effect, it is understood that the gap interval must be wide when the overlap is large. The curve H is located below the curve G. Therefore, by setting the combination of the gap dimension (y) and the overlap dimension (x) so as to fall within the range between the curves G and H, a high water sealing effect is obtained in the rotation range of 1800 to 1100. be able to.

(4). Other Embodiments and Reference Example FIG. 7 schematically shows another embodiment and a reference example . Among these, (A) shows an embodiment in which the annular rib 25 is provided only on the rotating body 24 to form the annular water seal portion 20 , and (B) shows only the engine main body 1 with the annular rib 25. This is an embodiment in which the annular water seal portion 20 is formed . (C) is a reference example in which an annular recess 26 is formed in the rotating body 24 and an annular rib 25 is provided in the engine body 1 to form a mechanical seal- like annular water seal portion 20. In (C), the arrangement of the annular recess 26 and the annular rib 25 may be reversed.

In the reference example shown in FIG. 7D, when the annular ribs 25 and 27 are provided on both the engine body 1 and the rotating body 24, the weight of the rotating body 24 is reduced by forming a plurality of the annular ribs 27. I am trying. A plurality of the annular ribs 25 of the engine body 1 may be formed, or both the annular ribs 25 and 27 may be formed of a plurality.

The present invention can be embodied in various ways in addition to the above embodiments. For example, an annular water seal can be formed between the crank pulley and the front cover by applying to a crank pulley as a rotating body. Further, grooves or protrusions that promote the discharge of water may be formed on the end surfaces of the ribs that constitute the annular water seal (that is, the ribs may have a pumping action) .

  The present invention can be embodied in an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder block 3 Oil pan 4 Crankshaft 7 Crankshaft main journal 9 Bearing part 11 Crank cap 12 Exposed end part of the crankshaft 13 Flywheel as an example of rotating body 16 Oil seal 17, 18 Body side water Oil seal holding rib as an example of sealing rib 19 Rotating body side water sealing rib 20 Annular water sealing portion

Claims (2)

One end portion of the crankshaft is exposed to the outside of the engine body, and a flywheel or other rotating body located outside the engine body is fixed to one end portion of the crankshaft, and the outer periphery of the crankshaft An oil seal is provided between the engine body and
Furthermore, an annular water seal portion with a narrow gap that prevents water from entering from a radially outer side to a portion radially outside the outer periphery of the oil seal among the portions where the engine body and the rotating body face each other. It is the structure formed integrally,
The engine body includes a cylinder block having a crank chamber opened downward, and an oil pan having an upward opening fixed to the lower surface of the cylinder block. The main body side water sealing ribs constituting the sealing part are formed approximately every half circumference, and the width dimension of the main body side water sealing rib provided in the oil pan is larger than the width dimension of the main body side water sealing rib provided in the cylinder block. On the other hand,
The rotating body includes a rotating body side water sealing rib having a width dimension substantially equal to or larger than the width dimension of the main body side water sealing rib provided on the oil pan, and the main body side water of the cylinder block and the oil pan. It is formed to face the sealing rib,
Internal combustion engine. One end portion of the crankshaft is exposed to the outside of the engine body, and a flywheel or other rotating body located outside the engine body is fixed to one end portion of the crankshaft, and the outer periphery of the crankshaft An oil seal is provided between the engine body and
Furthermore, an annular water seal portion with a narrow gap that prevents water from entering from a radially outer side to a portion radially outside the outer periphery of the oil seal among the portions where the engine body and the rotating body face each other. It is the structure formed integrally,
When the clearance dimension of the annular water seal portion is ymm, the overlap size of the annular water seal portion viewed from the crank axis direction is xmm, and the natural logarithm is Ln, y and x are y = −0. Included in a range between an approximate expression satisfying 0179x2 + 0.4773x and an approximate expression satisfying y = 1.018Ln (x) -0.9239,
Having a rotation range of 1100 to 1800 rpm,
Internal combustion engine.

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