JP2014122600A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of lubricating a sprocket and a timing chain immediately after startup of the engine.SOLUTION: An auxiliary oil path extending laterally is formed on a joint face between a pump housing part 12 and a pump cover 13 constituting an oil pump 20. To the other end (outlet) of the oil pump 20, an oil injection aperture 35 for injecting an oil to the outer circumferential face of a sprocket 15 communicates. The auxiliary oil path 34 has an upward concave shape such that a lowest part 34c exists between one end 34a and the other end 34b. Oil accumulates in the auxiliary oil path 34 after an engine is stopped, and immediately after the next startup, the oil that has accumulated is pushed by air to be injected, thereby lubricating the sprocket.

Description

  The present invention relates to an internal combustion engine in which a valve mechanism is driven by a timing chain or a timing gear.

  In general, a valve mechanism of an internal combustion engine is often driven by a timing chain. The timing chain is wound around a main sprocket fixed to a crankshaft and a driven sprocket fixed to a camshaft.

  The meshing surface between the sprocket and the timing chain is lubricated with oil. For example, in Patent Document 1, a sprocket lubrication oil passage communicating with an oil feed passage (oil gallery) is provided in the cylinder block, and this oil passage is provided. The structure which wets a sprocket with the oil which ejected from the is disclosed.

JP 09-25810 A

  Patent Document 1 relates to the application of the present applicant. Like this Patent Document 1, if an oil passage for sprocket lubrication is provided in a component member of an engine such as a cylinder block, the advantage that the structure can be simplified accordingly. However, as a result of examination by the inventors of the present application, it has been found that there is room for improvement in the lubrication of sprockets and the like in the prior art including Patent Document 1 immediately after the start of the engine.

  In other words, taking the timing chain drive system as an example, the oil that lubricates the sprocket is supplied from the oil pump, but when the operation of the engine is stopped, most of the oil in the oil feed passage provided in the engine is transferred to the oil pan by gravity. Since the oil flows down, immediately after the engine is started, there is no oil in the oil supply passage and oil filter, and air is present, so that the oil is pumped from the oil pump when the engine is started. While there is a slight time lag before reaching the sprocket, the timing chain is driven at the same time as the engine is started, so there is an unlubricated state in which the timing chain and sprocket are not lubricated with oil immediately after the start. For this reason, mechanical loss occurs, resulting in deterioration of fuel consumption, and resistance to sprockets and timing chains. Sex had may decrease.

  The present invention has been made in order to improve the present situation, and an object of the present invention is to enable accurate lubrication between the sprocket and the timing chain and between the timing gears immediately after starting.

  In order to achieve the above object, in the present invention, a sprocket or gear for driving the valve mechanism is fixed to the end of the crankshaft, and a member positioned near the sprocket or gear is attached to the sprocket or gear. In the internal combustion engine provided with an oil passage for ejecting upper oil on the outer peripheral surface, the auxiliary oil passage has a horizontally long shape in the horizontal direction, and at least part thereof is provided with an upward concave portion in which oil is accumulated. .

  In the present invention, examples of the member that provides the auxiliary oil passage include a cylinder block as in Patent Document 1, a chain cover that covers a sprocket and a gear, and an oil pump casing. Alternatively, the oil passage can be configured by a pipe attached to the cylinder block or the chain cover.

  In the present invention, since the auxiliary oil passage is horizontally long and has an upwardly concave portion, when the operation of the engine is stopped, oil remains in the auxiliary oil passage. At the same time as the next start, the oil pump is driven and air is first pushed out from the main passage, and the oil is pumped to the main passage with a slight time lag, but the air is pushed out and accumulated in the auxiliary oil passage. The oil is pushed out almost simultaneously with the drive of the oil pump and is ejected toward the outer peripheral surface of the sprocket or gear.

  This makes it possible to lubricate the sprocket and timing chain and gears immediately after starting, and as a result, prevent unlubricated states between the sprocket and timing chain or between gears. As a result, it is possible to remarkably suppress the loss of mechanical loss and to suppress the wear of the sprocket, timing chain, or gear, thereby improving the durability thereof.

  If the auxiliary oil passage is formed in a structural member of the engine such as an oil pump, a cylinder block, or a chain cover, there is an advantage that the structure is simplified as compared with the case where the auxiliary oil passage is constituted by a pipe.

1 is a side view of an internal combustion engine according to an embodiment. It is the perspective view which looked at the chain cover of 1st Embodiment from the outer side. It is a separation figure of a chain cover and a pump cover, and the chain cover is seen from the back side. (A) is a schematic cross-sectional view taken along the line IVA-IVA in FIG. 1, and (B) is a schematic cross-sectional view taken along the line IVB-IVB in FIG. (A) is the elements on larger scale of FIG. 3, (B) is BB sectional drawing of (A).

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the chain cover is also used as a part of the oil pump, and the auxiliary oil passage is provided in the pump cover constituting the oil pump.

  First, the first embodiment shown in FIGS. 1 to 5 will be described. This embodiment is applied to an internal combustion engine for a vehicle. As shown in FIG. 1, the internal combustion engine includes a cylinder block 3 having a cylinder bore 2 in which a piston 1 reciprocates, and a cylinder fixed to the upper surface of the cylinder block 3. A head 4 and a chain cover 5 fixed to one side of the cylinder block 3 and the cylinder head 4 are provided. An oil pan 6 is fixed to the lower surface of the cylinder block 3. On the other hand, a cylinder head cover 7 is fixed to the upper surface of the cylinder head 4.

  In the following description, in order to specify the direction, left and right and inner and outer words are used, and these left and right words are based on FIG. Further, with respect to the inner side and the outer side, when the chain cover 5 is used as a reference, the direction facing the cylinder block 3 is called the inner side, and the exposed side opposite to the cylinder block 3 is called the outer side. In this embodiment, FIG. 1 is a front view. Therefore, the side view is as seen from the horizontal direction orthogonal to the axis of the crankshaft 8.

  As shown in FIGS. 2 and 4A, the chain cover 5 has a peripheral wall 5a and has a shallow tray shape that opens toward the cylinder block 3 and the cylinder head 4. A shaft hole 9 through which the crankshaft 8 passes is vacant. As shown roughly in FIG. 4B, a machine drive pulley 10 is fixed to a portion of the crankshaft 8 exposed from the chain cover 5, and an auxiliary machine drive belt wound around the auxiliary machine drive pulley 10. 11, an auxiliary machine such as an alternator or a water pump is driven.

  The portion of the chain cover 5 that extends to the left and right sides with the shaft hole 9 as the center is a pump housing portion 12 that constitutes a part of the oil pump, and the pump cover 13 is superimposed on the pump housing portion 12 from the inside. The pump cover 13 is fixed to the pump housing portion 12 with a group of bolts 14 (see FIG. 4A). In FIG. 4, the pump cover 13 is schematically shown. As shown in FIG. 4A, a portion of the pump cover 13 around the crankshaft 8 is recessed, and a dynamic sprocket fixed to the crankshaft 8 is formed in the recessed portion as shown in FIG. 4B. 15 is arranged, and a timing chain 16 is wound around the sprocket 15.

  As shown in FIG. 4, a pump chamber 17 that is recessed outside the pump cover 13 is formed at a location around the crankshaft 8 in the pump housing portion 12, and an inner rotor that meshes with the pump chamber 17. 18 and an outer rotor 19 are arranged. Accordingly, an oil pump 20 is constituted by a part of the chain cover 5, the pump cover 13, and the rotors 18 and 19. Needless to say, the crankshaft 8 passes through the pump cover 13.

  On the mating surface of the pump housing portion 12 and the pump cover 13, a suction passage 21 that guides oil to the pump chamber 17 and a discharge passage 22 that discharges pressurized oil are formed so as to face in opposite directions. . The suction passage 21 and the discharge passage 22 are formed by recessing both the pump housing portion 12 and the pump cover 13.

  Although not shown, the outer periphery of the inner rotor 18 and the inner periphery of the outer rotor 19 are formed with unevenness that mesh with each other. The outer peripheral surface of the outer rotor 19 is a perfect circle, but the rotational axis of the inner rotor 18 and the rotational axis of the outer rotor 19 are slightly shifted from each other. Oil is pumped from 21 to the discharge passage 22.

  As shown in FIG. 3, an oil introduction passage 23 that extends downward is integrally formed in a portion of the pump cover 13 opposite to the pump housing portion 12, and the end of the oil introduction passage 23 is the end of the suction passage 21. Among them, it communicates with the left and right middle part. A suction unit having a strainer is fixed to the oil introduction passage 23.

  The oil that has exited the discharge passage 22 once reaches the oil filter 24, then returns to the relay passage 25 shown in FIG. 3, and is sent from the pipe-like discharge passage 26 to an oil feed passage such as an oil gallery.

  As clearly shown in FIG. 2, a filter holding portion 27 is formed at the end of the chain cover 5, and a screw cylinder 28 into which the oil filter 24 is screwed protrudes outwardly from the filter holding portion 27. Yes. An annular groove 29 located outside the screw cylinder 28 is formed on the outer surface of the filter holding portion 29, and a relay hole 30 communicating with the relay passage 25 is provided at the annular groove 29.

  As shown in FIG. 3, the pump housing portion 12 and the pump cover 13 are formed with a relief passage 31 that returns the oil to the suction passage 21 when the oil discharge pressure becomes higher than a set value. Although not described in detail, the relief passage 31 communicates with the suction passage 21 via the upper end portion of the cylindrical portion 32, and a relief valve biased by a spring is fitted into the cylindrical portion 32.

(2) Auxiliary oil passage As shown in FIGS. 3 and 5, the auxiliary oil for lubricating the sprocket 15 is generally disposed above the discharge passage 22 in the mating surface of the pump housing portion 12 and the pump cover 13. A passage 34 is provided. The auxiliary oil passage 34 has a horizontally long form, and one end 34a is close to the relay passage 25 and communicates with the relay passage 25 through a hole. Therefore, the oil filtered by the oil filter 24 is pumped into the auxiliary oil passage 34.

  The auxiliary oil passage 34 is formed by forming a groove in the pump housing portion 12 and the pump cover 13, and the other end portion is located at the upper portion of the crankshaft 6. The other end 34b of the auxiliary oil passage 34 in the pump cover 13 communicates with an oil ejection hole 35 that opens toward the outer periphery of the sprocket 15 as shown in FIG. Therefore, the sprocket 15 and the timing chain 16 are lubricated when the sprocket 15 gets wet with oil.

  The auxiliary oil passage 34 is substantially horizontally long and horizontally long, but is generally concave upward (or downward convex) so that the lowest portion 34c exists between one end 34a and the other end 34b. It is in form. For this reason, as indicated by horizontal parallel oblique lines in FIG. 5A, the oil remains in the auxiliary oil passage 34 even after the engine is stopped, and at the next start-up, the auxiliary oil passage 34 is retained. The oil accumulated in the air is pushed by the air and immediately spouts toward the sprocket 15. Thereby, the lubrication between the sprocket 15 and the timing chain 16 immediately after starting is performed accurately.

  Although the auxiliary oil passage 34 of the present embodiment has a shape that is generally close to a square shape when viewed from the front, a substantially U shape, a U shape having an upward opening, or the like can also be employed. Further, it is sufficient that at least a part of the auxiliary oil passage 34 has an upward concave portion in which oil can be stored, and the oil does not need to be stored in the entire auxiliary oil passage 34. If the angle or curvature of the auxiliary oil passage 34 is small, the oil flow resistance increases. Therefore, it can be said that the curvature and the curvature are preferably as large as possible as in the embodiment.

  When the auxiliary oil passage 34 is formed on the mating surface of the pump housing portion 12 and the pump cover 13, the auxiliary oil passage 34 is formed by forming a groove only in the pump housing portion 12 or only in the pump cover 13. It may be configured. If the auxiliary oil passage 34 is formed on the mating surfaces of the members, it can be formed in an upwardly concave shape without any special processing, which is advantageous in terms of cost.

  In the present embodiment, the auxiliary oil passage is provided in the pump cover. However, the auxiliary oil passage may be provided in the cylinder block or in the chain cover. When the oil pump has a configuration independent of the chain cover, it can be provided in the pump housing. It is also possible to form the oil reservoir by forming the auxiliary oil passage with a pipe material without forming it in the pump cover or the like, and bending the pipe material downwardly into a concave shape.

  Further, the vertical width of the auxiliary oil passage does not have to be equal, and for example, the upper surface of the auxiliary oil passage may be in the form of an inverted triangle with the horizontal posture and the lower surface recessed downward. Therefore, in the present invention, at least the lower surface of the upper and lower inner surfaces of the auxiliary oil passage only has to be “concave upward”.

  The present invention is actually applicable to an oil pump. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder block 5 Chain cover 8 Crankshaft 12 Pump housing part which comprises an oil pump 13 Pump cover 15 Sprocket 16 Timing chain 20 Oil pump 21 Intake passage 22 Discharge passage 34 Auxiliary oil passage 34a One end (inlet)
34b The other end (exit)
34c Lowest part 35 Oil jet hole

Claims (1)

A sprocket or gear for driving the valve operating mechanism is fixed to the end of the crankshaft, and auxiliary oil that jets upper oil to the outer peripheral surface of the sprocket or gear on a member located near the sprocket or gear It is the structure which has provided the passage,
The auxiliary oil passage has a horizontally long shape that is long in the horizontal direction, and at least a part thereof is provided with an upward concave portion for collecting oil.
Internal combustion engine.

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