JP5069161B2 - Lubrication structure of internal combustion engine - Google Patents

Description

  The present invention relates to an improvement in the lubrication structure of an internal combustion engine.

There is known an internal combustion engine provided with a relief valve mechanism that sends lubricating oil discharged from an oil pump to a lubrication target portion via an oil passage, and releases the lubricating oil when the oil pressure exceeds a predetermined value in the oil passage. (For example, refer to Patent Document 1).
JP 2001-140617 A (FIGS. 2 and 3)

In FIG. 2 of Patent Document 1, reference numeral 25 denotes an oil pump, and reference numeral 54 denotes a relief valve. The relief valve 54 has a detailed structure shown in FIGS.
That is, when the hydraulic pressure is less than or equal to a predetermined value, the valve body 54b closes the relief passage 54n as shown in (a). When the hydraulic pressure exceeds a predetermined value, as shown in (b), the coil spring 54d is contracted, the valve body 54b moves, and the lubricating oil escapes to the relief passage 54n. When the hydraulic pressure decreases, the valve body 54b returns to the valve closed position. That is, the valve body 54b reciprocates between the valve open position and the valve close position, thereby preventing the hydraulic pressure from rising above a predetermined value.

By the way, when the present inventors investigated, there is a difference between the hydraulic pressure fluctuation when the internal combustion engine is in the low rotation state and the hydraulic pressure fluctuation when the internal combustion engine is in the high rotation state, and the hydraulic pressure fluctuates in a shorter cycle as the rotation speed becomes higher. I found out.
It has been confirmed that the valve body 54b of the relief valve exhibits a relief action by sufficiently following the pressure fluctuation when the rotation is low.

  However, when the rotation speed is high, the speed of pressure fluctuation exceeds the moving speed of the valve body 54b, and as a result, the moving amount (lift amount) of the valve body 54b may be reduced.

  Therefore, a lubrication structure that can exert a relief action more preferably during high rotation is desired.

  An object of the present invention is to provide a lubrication structure capable of exhibiting a relief effect more preferably at high revolutions in an internal combustion engine.

The invention according to claim 1 is provided with a relief valve mechanism for releasing the lubricating oil when the oil pressure exceeds a predetermined value in the oil passage, and the lubricating oil discharged from the oil pump is supplied to the lubrication target portion via the oil passage. In the lubrication structure of the internal combustion engine to send,
In the relief valve mechanism, the first valve body is held closed when the hydraulic pressure is equal to or lower than a first predetermined value, and the first valve body is opened when the hydraulic pressure exceeds the first predetermined value. A first relief valve for escaping the lubricating oil to the first relief passage;
The valve is closed when the hydraulic pressure is equal to or lower than a second predetermined value higher than the first predetermined value, and when the hydraulic pressure exceeds the second predetermined value, the valve is opened to feed the lubricating oil to the second relief passage. for example Bei and a second relief valve to escape,
The second predetermined value is a value between the hydraulic pressure peak at which the pressure applied in the oil passage is maximum and the first predetermined value, and a value in the vicinity of the hydraulic pressure peak,
The first relief valve includes a biasing means for holding the first valve body in a valve closed position by a biasing action,
The second relief valve is a rotary valve body that is rotationally driven by a rotating means, and is held at the valve closed position by the biasing action of the biasing means when the hydraulic pressure is less than or equal to the second predetermined value. When the second predetermined value is exceeded, the valve hole is moved to the valve opening position against the biasing means, and the valve hole provided in the rotary valve body is configured to face the second relief passage. And

In the invention according to claim 2 , the first valve body is provided at one end of the rotary valve body, and the biasing means of the second relief valve also serves as the biasing means of the first relief valve, and is a hollow provided in the rotary valve body. The portion communicates with the oil passage and can communicate with the second relief passage through the valve hole.

The invention according to claim 3 is characterized in that the rotation means is a transmission means delivered to the oil pump shaft and the rotary valve body.
In the invention according to claim 4, the thrust bearing is provided to make the first valve body rotatable with respect to the biasing means, the hollow portion penetrates the thrust bearing, and the biasing means is provided via the thrust bearing. The valve body is biased.

In the invention according to claim 1, the first relief valve that does not depend on the rotational speed and the second relief valve that follows the rotational speed exert a relief action to release the lubricating oil. The second relief valve allows a small amount of lubricating oil to escape during low rotation, and allows a large amount of lubricating oil to escape during high rotation.
Therefore, the relief action can be exerted more preferably during high rotation.

In addition, in the invention according to claim 1 , the second predetermined value is a value between the peak of the hydraulic pressure at which the pressure applied in the oil passage is maximum and the first predetermined value, and in the vicinity of the peak of the hydraulic pressure. Was set to the value of The first relief valve is opened and closed at a first predetermined value smaller than the second predetermined value, and the second relief valve is opened and closed at a value near the peak of the hydraulic pressure. For this reason, when the hydraulic pressure reaches a peak, the oil is released by both the first relief valve and the second relief valve to promptly level the hydraulic pressure.

In addition, in the invention according to claim 1 , the first relief valve that does not depend on the rotational speed and the second relief valve that follows the rotational speed exert a relief action to allow the lubricating oil to escape. The second relief valve allows a small amount of lubricating oil to escape during low rotation, and allows a large amount of lubricating oil to escape during high rotation.
At this time, the first relief valve and the second relief valve are operated by the biasing means and the rotation means.
The biasing means represented by the spring and the rotation means represented by the gear can be easily configured, and the lubrication structure can be made simple.

In the invention according to claim 2 , the first valve body is provided at one end of the rotary valve body, and the urging means of the second relief valve also serves as the urging means of the first relief valve.
Compared with the case where the first relief valve and the second relief valve are separately arranged, the present invention in which the first relief valve is integrated with the second relief valve can reduce the number of parts and reduce the size.

In the invention according to claim 3 , the rotation means is a transmission means delivered to the oil pump shaft and the rotary valve body. The rotational speed of the oil pump shaft is proportional to the rotational speed of the internal combustion engine. If the rotary valve body is rotated by such an oil pump shaft, the lubricating oil can be released in proportion to the rotation speed.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a circuit diagram of lubricating oil for an internal combustion engine according to the present invention. Lubricating oil 12 stored in an oil pan 11 is pumped up and pressurized by an oil pump 14 via a strainer 13. The pressurized lubricating oil is sent to the lubrication target portion 16 via the oil passage 15. The lubricating oil that has been lubricated is returned to the oil pan 11 through the return passage 17.
The oil passage 15 is provided with a relief valve mechanism 20. Lubricating oil can be released from the relief valve mechanism 20 using the first relief passage 21 and the second relief passage 22.

The detailed structure of the relief valve mechanism 20 will be described with reference to the next drawing.
FIG. 2 is a view showing the structure of the relief valve mechanism according to the present invention. The relief valve mechanism 20 is a mechanism provided in the oil passage 15 provided in the cylinder block 23 and is branched from the oil passage 15. The cylindrical branch oil passage 24, the disc-shaped first valve body 26 slidably fitted in the branch oil passage 24, and the first valve body 26 do not come out to the oil passage 15 side. A retaining ring 27 provided in the branch oil passage 24 and a biasing means 28 such as a compression spring provided in the back of the branch oil passage 24 for biasing the first valve body 26 to the retaining ring 27. A thrust bearing 29 that allows the first valve body 26 to rotate with respect to the biasing means 28, a first valve seat 31 formed in the branch oil passage 24 adjacent to the retaining ring 27, and a first A cylindrical rotary valve body 33 extending from the valve body 26 to the opposite side of the oil passage 15, and this rotation A valve hole 35 from the hollow portion 34 leads to the outer peripheral surface provided in the middle of the body 33, and a second valve seat 36. which is formed in the cylinder block 23 side so as to surround the valve hole 35.

The relief valve mechanism 20 is driven by the rotating means 40.
The rotation means 40 is, for example, a transmission means 42 delivered to the oil pump shaft 41 and the rotary valve body 33.
The transmission means 42 includes, for example, a drive gear 43 provided on the oil pump shaft 41 and a driven gear 44 provided on the rotary valve body 33. The transmission means 42 may be a pair of sprockets and one chain.

  Specifically, the transmission means 42 includes a drive gear 43 that is fixed to one end of the oil pump shaft 41 with a bolt 45, and a driven gear that meshes with the drive gear 43 and is fixed to one end of the rotary valve body 33 with a bolt 46. And a gear 44. An oil seal 47 is interposed between the rotary valve body 33 and the cylinder block 23 to prevent leakage of lubricating oil.

  The first relief valve 25 is configured by the first valve body 26, the first valve seat 31, the urging means 28, and the first relief passage 21. If the oil pressure of the oil passage 15 is less than or equal to a predetermined value, the urging action of the urging means 28 is won and the first valve body 26 faces the first valve seat 31. That is, the first relief valve 25 is in a valve closed state.

The second relief valve 32 is constituted by the valve hole 35 of the rotary valve body, the second valve seat 36, the second relief passage 22, and the rotating means 40.
As described above, the biasing means represented by the spring and the rotation means represented by the gear can be easily configured, and the lubrication structure can be simplified.

  3 is a cross-sectional view taken along line 3-3 in FIG. 2, and the second valve seat 36 is a complete circumferential wall. Therefore, even if the rotary valve body 33 rotates 360 °, the valve hole 35 remains in the second valve seat 36. Continue to be blocked. That is, the second relief valve 32 is in a valve closed state.

Next, an operation when the hydraulic pressure that is equal to or less than a predetermined value (first predetermined value or second predetermined value) exceeds a predetermined value will be described with reference to FIG.
When the oil pressure in the oil passage 15 exceeds the first predetermined value, the force indicated by the arrow (1) acts on the first valve body 26, against the biasing means 28, the first valve body 26, the rotary valve body 33, The valve hole 35, the thrust bearing 29, and the driven gear 44 start to move in the direction of the arrow (2) collectively. With this movement, first, the oil passage 15 and the first relief passage 21 are brought into a communication state. This state will be described with reference to FIG.

  When the oil pressure in the oil passage 15 exceeds a second predetermined value that is higher than the first predetermined value, the valve hole 35 is in communication with the second relief passage 22. At this time, the communication state between the oil passage 15 and the first relief passage 21 continues. This state will be described with reference to FIG.

  That is, the positional relationship among the first valve body 26, the first relief passage 21, the valve hole 35, and the second relief passage 22 is such that the first valve body 26 is kept closed when the hydraulic pressure is equal to or lower than the first predetermined value. When the hydraulic pressure exceeds the first predetermined value, the first valve body 26 opens and the oil is released to the first relief passage 21, and when the hydraulic pressure is equal to or lower than the second predetermined value higher than the first predetermined value. When the valve is in the closed state and exceeds the second predetermined value, the valve is opened and the oil is set to escape to the second relief passage 22.

  Thus, the amount of movement of the rotary valve body 33 and the like is determined in proportion to the hydraulic pressure. The tooth width of the drive gear 43 is determined in anticipation of the maximum amount of movement. Thus, there is no fear that the driven gear 44 is detached from the drive gear 43.

FIG. 4 is an explanatory diagram when the first relief valve and the second relief valve are in the valve open state. When the hydraulic pressure exceeds the first predetermined value, the first valve body 26 moves away from the first valve seat 31. The lubricating oil escapes to the first relief passage 21 as shown by the arrow (3).
Next, when the hydraulic pressure exceeds the second predetermined value, the lubricating oil escapes through the hollow portion 34 and the valve hole 35 to the second relief passage 22 as indicated by an arrow (4).

  The drive gear 43 and the driven gear 44 should be synchronized so that the valve hole 35 faces the second relief passage 22 near the peak discharge pressure of the oil pump (FIG. 1, reference numeral 14). The position adjustment (phase adjustment) in the rotation direction is made and combined.

5 is a cross-sectional view taken along line 5-5 of FIG. 4. When the valve hole 35 faces the second relief passage 22, the lubricating oil passes through the valve hole 35 as indicated by the arrow (4). Run away. However, when the rotary valve body 33 rotates and the valve hole 35 does not face the second relief passage 22, the valve hole 35 is closed by the second valve seat 36, so that the valve is closed.
FIG. 6 is an explanatory view of the operation of the second relief valve, and the valve open state appears only once while the rotary valve body makes one rotation. However, the valve is closed most of the time.

Next, the necessity of the relief valve mechanism 20 will be examined in relation to the rotational speed of the internal combustion engine.
7A and 7B are diagrams for explaining the relationship between the rotational speed of the internal combustion engine and the relief amount. FIG. 7A shows the pressure of the oil passage 15 in the low rotation range, and FIG. 7B shows the lift amount of the first valve body in the low rotation range. (C) is the pressure of the oil passage 15 in the middle rotation region, (d) is the lift amount of the first valve body in the middle rotation region, (e) is the pressure of the oil passage 15 in the high rotation region, ( f) shows the lift amount of the first valve body in the high speed range.
The

In (a), a solid line indicates a case where the first relief valve 25 is not provided, and a broken line indicates a case where the first relief valve 25 is provided. In (b), the solid line indicates the lift amount of the first valve body 26.
That is, in the low rotation range, the first valve body is followed so that the lift amount becomes maximum in the vicinity of the hydraulic pressure peak. As a result, excess oil can escape from the first relief passage 21.

In (c), a solid line indicates a case where the first relief valve 25 is not provided, and a broken line indicates a case where the first relief valve 25 is provided. In (d), the solid line indicates the actual lift amount of the first valve element 26, and the chain line indicates the ideal lift characteristic of the first valve element 26.
That is, it is desirable that the lift amount be maximized in the vicinity of the hydraulic pressure peak in (c), as indicated by the chain line in (d).
However, in the middle rotation range, the position where the lift amount of the first valve body indicated by the solid line in (d) is maximized is delayed from the position where the hydraulic pressure peak shown in (c). For this reason, it is difficult to increase the oil relief amount at the peak of the hydraulic pressure. As a result, pressure fluctuation occurs even with the relief shown by the broken line in FIG.

  In (e) and (f) showing the high rotation range, the influences appearing in (c) and (d) appear more remarkably.

  As described above, in the middle rotation range and the high rotation range, the follow-up delay of the first valve body 26 occurs with respect to the pressure fluctuation of the oil passage 15, so that the oil relief amount is insufficient. As a countermeasure against this, the present invention is provided with the valve hole 35 and the second relief passage 22 (see FIG. 4) in order to relieve the oil that the first valve body 26 could not escape at the peak of hydraulic pressure. The operation and effect will be described in a simple manner with the following figure.

  FIG. 8 is a diagram for explaining the overall operation of the lubricating structure according to the present invention. As shown in FIG. 8A, when the hydraulic pressure exceeds a predetermined value and is a certain value, the first relief valve is used. A certain relief amount (first relief amount) is generated. The first relief amount depends on the hydraulic pressure and is not related to the rotational speed of the internal combustion engine.

  On the other hand, as shown in (b), when the hydraulic pressure exceeds a predetermined value and is at a certain value and when the engine speed is low, the relief amount of the second relief valve is small. When the hydraulic pressure exceeds a predetermined value and is at a certain value and when the engine is rotating at a medium speed, the relief amount of the second relief valve becomes a medium amount, and when the hydraulic pressure exceeds a predetermined value and is at a certain value, it is high. At the time of rotation, the relief amount of the second relief valve becomes large.

  That is, at the time of high rotation, the time during which the first valve body 26 shown in FIG. 4 is moving to the second relief passage 22 side by the oil supplied from the oil passage 15 is longer than in the low rotation state. In addition, the amount of relief discharged from the valve hole 35 increases due to an increase in centrifugal force resulting from an increase in the rotational speed of the first valve body 26.

Then, the sum of the relief amounts (first relief amount + second relief amount) is the sum of the portion depending on the pressure and the portion depending on the rotational speed, as shown in (c). Change.
In the part depending on the pressure alone, the relief amount was insufficient at high rotation. However, according to the present invention in which the portion depending on the rotation speed is added to the portion depending on the pressure, the relief amount at the time of high rotation becomes a sufficient amount.

  In the embodiment, the rotation means uses an oil pump shaft as a drive source, but a crankshaft or a camshaft may be used as a drive source. Further, the rotation means may be a servo motor whose rotation speed is controlled based on a rotation speed signal.

  In the embodiment, the first relief valve and the second relief valve are integrated, but the first relief valve and the second relief valve may be provided separately. Although the number of parts increases, the degree of freedom in layout increases.

  Furthermore, the lubricating structure of the present invention is suitable for a motorcycle having a large rotational speed range of an internal combustion engine. However, the lubrication structure of the present invention can be applied to tricycles and four-wheel vehicles, and can be applied to general vehicles.

  The lubricating structure of the present invention is suitable for an internal combustion engine of a motorcycle.

It is a circuit diagram of the lubricating oil of the internal combustion engine which concerns on this invention. It is a figure which shows the structure of the relief valve mechanism which concerns on this invention. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is explanatory drawing when a 1st relief valve and a 2nd relief valve are in a valve open state. FIG. 5 is a sectional view taken along line 5-5 of FIG. It is operation | movement explanatory drawing of a 2nd relief valve. It is a figure explaining the relationship between the rotational speed of an internal combustion engine, and the relief amount. It is a figure explaining the comprehensive effect | action of the lubricating structure which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Lubrication oil, 14 ... Oil pump, 15 ... Oil path, 16 ... Lubrication target part, 20 ... Relief valve mechanism, 21 ... 1st relief path, 22 ... 2nd relief path, 25 ... 1st relief valve, 26 ... 1st valve body, 28 ... biasing means, 31 ... 1st valve seat, 32 ... 2nd relief valve, 33 ... rotary valve body, 34 ... hollow part, 35 ... valve hole, 36 ... 2nd valve seat, 40 ... Rotating means, 41 ... oil pump shaft , 42 ... transmission means, 43 ... drive gear, 44 ... driven gear.

Claims (4)

Oil passage (15) to the hydraulic lubricating oil Once exceeds a predetermined value (12) a relief valve mechanism for releasing (20) is provided, the lubricating oil discharged from the oil pump (14) to (12), the fluid passage In the lubricating structure of the internal combustion engine sent to the lubrication target part (16) via (15) ,
The relief valve mechanism (20) holds the first valve body (26) closed when the hydraulic pressure is equal to or lower than a first predetermined value, and the first valve body (26) when the hydraulic pressure exceeds the first predetermined value. A first relief valve (25) in which the valve body (26) is opened and the lubricating oil (12 ) is allowed to escape to the first relief passage (21) ;
When the hydraulic pressure is lower than a second predetermined value higher than the first predetermined value, the valve is closed. When the hydraulic pressure exceeds the second predetermined value, the valve is opened and the lubricating oil (12) is supplied to the second oil. second relief valve to escape to the relief passage (22) (32) and Bei give a,
The second predetermined value is a value between the hydraulic pressure peak at which the pressure applied in the oil passage (15) is maximum and the first predetermined value, and is a value in the vicinity of the hydraulic pressure peak. ,
The first relief valve (25) includes a biasing means (28) for holding the first valve body (26) in the valve closed position by a biasing action.
The second relief valve (32) is a rotary valve body (33) that is rotationally driven by the rotating means (40), and the biasing means (28) is energized when the hydraulic pressure is equal to or less than the second predetermined value. When the hydraulic pressure exceeds the second predetermined value, the valve is moved to the valve open position against the biasing means (28) and provided on the rotary valve body (33). A lubricating structure for an internal combustion engine, characterized in that the valve hole (35) faces the second relief passage (22) . Wherein said one end of the rotary valve element (33) the first valve (26) is provided, the urging of the biasing means (28) is the first relief valve (25) of the second relief valve (32) The second relief passage also serves as the means (28), and the hollow portion (34) provided in the rotary valve body (33) communicates with the oil passage (15) and through the valve hole (35). 2. A lubricating structure for an internal combustion engine according to claim 1 , wherein the lubricating structure is capable of communicating with (22) . Said rotation means (40), the lubricating structure according to claim 1 or claim 2, wherein the internal combustion engine, characterized in that a transmission means passed to the oil pump shaft (41) said rotary valve element (33) .   A thrust bearing (29) for rotating the first valve body (26) relative to the biasing means (28), the hollow portion (34) penetrating the thrust bearing (29), and The lubricating structure for an internal combustion engine according to claim 1, wherein the urging means (28) urges the first valve body (26) via the thrust bearing (29).

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