JP4476145B2 - Valve cooling device - Google Patents

Description

  The present invention relates to a cooling device that cools a valve that opens and closes an intake / exhaust passage connected to a combustion chamber of an engine.

  The intake valve that opens and closes the intake passage that supplies the air-fuel mixture to the combustion chamber of the engine and the exhaust valve that opens and closes the exhaust passage that discharges combustion gas from the combustion chamber to the outside are always exposed to high temperatures. In order to protect from damage, it is necessary to cool, and conventionally, various cooling means have been proposed. For example, an internal cooling type valve is known in which the inside of the valve stem of the valve is hollow and metallic sodium having good thermal conductivity is sealed in the hollow portion. According to this valve, metallic sodium liquefies during operation, swings due to the opening and closing movement of the valve, transfers the heat of the valve head to the valve stem and releases it, thereby reducing the temperature of the valve head that is particularly exposed to high temperatures. Reduced and protected.

  Since the valve contains metal sodium that reacts violently with air and water, it is necessary to extract the metal sodium sealed from the valve when discarding the engine, which is a costly problem. Yes. Further, the heat conducted from the valve head to the valve stem is only transferred to the valve guide of the cylinder head supporting the valve stem and escapes, and the effect of lowering the valve temperature is not so great.

  Therefore, recently, cooling oil is used instead of metallic sodium, and this oil is supplied from the valve stem to the valve head, while returning from the valve head to the valve stem and discharged to the outside of the valve. A cooling device of the type that cools the valve head by circulating inside the valve stem has been proposed.

  For example, the valve stem is provided with an oil inflow passage at the center of the valve stem, and a plurality of oil outflow passages are provided at appropriate intervals in the circumferential direction on the circumference around the shaft center, so that the cylinder head can be used during engine operation. Oil is supplied from the oil supply passage to the oil inflow passage through the annular groove of the valve lifter, etc., and the oil is guided to the oil reservoir of the valve head, while discharged from the oil reservoir to the outside of the valve through the oil outflow passage. The thing comprised so that it may be proposed (refer patent document 1).

  Also, cooling water is used in place of oil, and this cooling water is supplied from the through hole provided in the shaft center of the valve stem to the cooling chamber provided in the valve head through the supply communication hole, while returning from the cooling chamber. There has also been proposed a configuration that discharges from the recess and the opening to the outside of the valve through the communication hole (see Patent Document 2).

  Further, in order to supply oil into the valve, there has been proposed one that supplies oil to the valve via a rocker arm that drives the valve in conjunction with a rotating cam (see Patent Document 3). According to this, an oil passage is provided in the rocker arm, and oil is supplied from the oil passage to an end portion (valve stem end) of the valve stem through an inflow hole provided in the shaft center of the end face of the valve stem. Oil was allowed to flow to the valve head through a cooling passage extending from the end of the valve stem to the valve head, and this oil was again flowed from the valve head to the end of the valve stem via the cooling passage, and was provided near the end. The oil is discharged to the outside of the valve through the outflow hole.

JP-A-5-163910 Japanese Utility Model Publication No. 62-10211 JP-A-5-202747

  In the above-described two valve cooling devices (Patent Documents 1 and 2), the valve stem has a passage for guiding oil or cooling water to the valve head, and a discharge passage for guiding oil or cooling water from the valve head to the outside of the valve. Therefore, there is a problem that the structure inside the valve stem is complicated, and it takes time to manufacture the valve, which increases the cost.

  In the valve cooling device of the latter (Patent Document 3), oil is supplied to the inside of the valve stem via the rocker arm. Therefore, even when the rocker arm swings, the oil passage of the rocker arm, the cooling passage of the valve stem, Need to be able to supply oil through constant communication, and the structure of the contact portion between the rocker arm and the valve stem is required to be processed with high accuracy, which increases the cost. Also, depending on the processing accuracy, there is a problem that oil leaks at the contact portion between the rocker arm and the valve stem, and the oil is not sufficiently supplied from the rocker arm to the valve stem. Furthermore, the oil is only supplied from the rocker arm, and the oil is discharged by the oil supplied to the inside of the valve stem, and the oil may not circulate smoothly inside the valve stem. There is.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a reliable valve cooling device that has a simple structure, is not expensive, has sufficient cooling capacity, and is reliable.

  The valve cooling device according to claim 1 of the present invention that achieves the above object is a cooling device that is driven by a cam and cools a valve that opens and closes an intake / exhaust passage connected to a combustion chamber of the engine with cooling oil. A hollow portion extending from the valve stem end of the valve to the valve head is provided inside the valve stem of the valve, and a valve lifter (valve follower) driven by the cam is provided at the valve stem end. And a supply / discharge passage for supplying cooling oil to the hollow portion and discharging the cooling oil from the hollow portion, and a valve lifter holding portion disposed on the cylinder head of the engine for holding the valve lifter slidably and rotatably. A supply passage for supplying the cooling oil to the hollow portion through the supply / discharge passage. The cooling oil is supplied to the hollow portion from the supply passage through the supply / discharge passage by being driven by the cam and the valve lifter slides in the valve lifter holding portion. The cooling oil is discharged from the hollow portion to the outside of the valve through a discharge passage (see FIGS. 1 and 2).

  As the cooling oil, for example, lubricating oil that lubricates between the valve lifter and the valve lifter holding portion is used (Claim 2).

  Further, the supply of the cooling oil to the hollow portion and the discharge from the hollow portion are driven by the cam, and when the valve head opens the intake / exhaust passage, the valve lifter moves inside the valve lifter holding portion. Sliding in one direction to open the supply passage and communicating the supply passage with the supply / discharge passage to supply the cooling oil to the hollow portion (see FIG. 1 or FIG. 4A), When the valve head closes the intake / exhaust passage, the valve lifter slides in the valve lifter holding portion in the other direction to close the supply passage and causes the supply / discharge passage to protrude from the valve lifter holding portion, The cooling oil in the hollow portion is discharged to the outside of the valve through a discharge passage (see FIG. 2 or FIG. 4C) (Claim 3). . That is, the valve lifter and the valve lifter holding part function as an opening / closing valve for the supply passage, supplying cooling oil to the hollow portion of the valve stem in accordance with the opening / closing operation of the intake / exhaust passage, and discharging the cooling oil from the hollow portion In this way, new cooling oil is always circulated in the valve.

  According to the valve cooling device of the present invention, new cooling oil is constantly circulated in the hollow portion of the valve stem, so that the temperature reduction effect can be achieved as compared with the type of cooling device in which alkali metal (sodium metal) is enclosed. It is large and knocking hardly occurs, and the knock limit can be further improved (ignition timing can be further advanced). In addition, there is one hollow part that circulates the cooling oil in the valve stem, and the supply of the cooling oil to the hollow part and the discharge of the cooling oil from the hollow part are the supply / discharge provided in the valve lifter. Since it is performed at one place in the passage, the structure is extremely simple and the manufacturing is easy, and therefore the manufacturing cost can be kept low. Further, the valve lifter and the valve lifter holding part serve as a valve, and supply and discharge of the cooling oil can be controlled.

  In addition, when using a lubricating oil that lubricates between the valve lifter and the valve lifter holding portion as a cooling oil, it is not necessary to prepare the oil for cooling.

  In addition, the supply and discharge of cooling oil is linked to the opening / closing operation of the intake / exhaust passage by the valve, so that the intake / exhaust passage is opened (especially when the valve is exposed to high-temperature combustion gas from the combustion chamber). If the cooling oil is supplied to cool the valve and the cooling oil used to cool the valve is discharged when the intake / exhaust passage is closed, the cooling oil is not always required. Compared to the case where the valve is cooled by circulation, the required amount of cooling oil is sufficient, and a predetermined cooling capacity can be secured even with the minimum required amount of cooling oil.

  Embodiments of a valve cooling device of the present invention will be described below with reference to FIGS.

  First, an outline of a valve to which the valve cooling device of this embodiment is applied will be described. As shown in FIGS. 1 and 2, the exhaust port for supplying an air-fuel mixture into the combustion chamber 10 of the engine, and the exhaust for discharging combustion gas (exhaust gas) from the combustion chamber 10 to the exhaust passage 12. Valves (intake / exhaust valves) 20 are disposed at the exhaust port portions of the passage 12 respectively. These valves 20 are directly driven by a cam device 14 composed of a cam 14a and a camshaft 14b disposed in the cylinder head 13 of the engine to open and close the intake port portion of the intake passage 11 and the exhaust port portion of the exhaust passage 12, respectively. A valve head 21 that opens and closes an intake port of the intake passage 11 and an exhaust port of the exhaust passage 12, a valve stem 22 that is connected to one end of the valve head 21, and a valve stem end of the valve stem 22. And a valve lifter 23 disposed on the surface. The intermediate portion of the valve stem 22 is slidably supported by a valve stem guide 15 disposed in the cylinder head 13 of the engine. The valve lifter 23 is slidably and rotatably fitted in a valve lifter holding portion 16 disposed in the cylinder head 13 of the engine, and is driven directly by the cam 14 to slide in the axial direction within the valve lifter holding portion 16. A retainer 24 is disposed in the vicinity of the valve stem end of the valve stem 22, and a valve spring 25 that constantly biases the valve 20 (valve lifter 23) toward the cam 14 a is disposed between the retainer 24 and the cylinder head 13. .

  Next, a cooling device for cooling the above-described valve 20 will be described. This cooling device supplies lubricating oil that lubricates between the valve lifter 23 and the valve lifter holding portion 16 as cooling oil to the inside of the valve 20 as the valve 20 is opened and closed. Cooling oil is circulated inside the valve 20 so as to be discharged so as to cool the valve 20 and includes a hollow portion 26, a supply / discharge passage 27, an oil reservoir 17, a supply groove 18, and the like.

  Specifically, as shown in FIGS. 1 and 2, the valve stem 22 is hollow, and the above-described hollow portion 26 extending in the axial direction between the valve head 21 and the valve lifter 23 is formed therein. The The hollow portion 26 has a large inner diameter on the valve head 21 side and a small inner diameter on the valve lifter 23 side. The hollow portion 26 is opened at the valve stem end.

  The valve lifter 23 is formed with the above-described supply / discharge passage 27 communicating with the hollow portion 26 at the head thereof. As shown in FIGS. 3A and 3B, the supply / discharge passage 27 includes a circumferential groove portion 27a formed on the outer peripheral surface of the head of the valve lifter 23, and the head of the valve lifter 23 at the position of the circumferential groove portion 27a. Two through-hole portions 27b extending perpendicularly to each other and perpendicular to each other and communicating with the circumferential groove portion 25, and extending in the axial direction at the center of the head portion of the valve lifter 23, and one end of the two through-hole portions It is comprised from the hole part 27b and the axial hole part 27c connected by those cross | intersection parts. The other end of the shaft hole portion 27c opens, and the valve stem end opening end of the hollow portion 26 communicates with the shaft center in a state where the shaft center coincides with the axial center of the hollow portion 26.

  Further, the valve lifter holding portion 16 has a circumferential groove portion 27a of the valve lifter 23 on the inner peripheral surface where the above-described oil reservoir 17 and the valve lifter 23 are fitted to temporarily store lubricating oil serving as cooling oil. A supply groove 18 serving as the above-described supply passage is provided. The oil reservoir 17 is supplied with lubricating oil via a lubricating oil tank, a pump, etc. (not shown). The supply groove 18 is provided over a predetermined length in the axial direction on the entire inner peripheral surface of the valve lifter holding portion 16. Specifically, the supply groove 18 slides in a direction in which the valve lifter 23 enters the valve lifter holding portion 16 as the head of the valve lifter 23 is pushed by the cam 14 a, so that the valve head 21 is connected to the exhaust port of the exhaust passage 12. And the intake port portion of the intake passage 11 are set to communicate with the circumferential groove portion 27a of the valve lifter 23 (see FIGS. 1 and 4A). Further, the supply groove 18 slides in a direction in which the cam 14 a escapes from the valve lifter 23 and the valve lifter 23 is escaped from the valve lifter holding portion 16 by the valve spring 25, so that the valve head 21 is exhausted from the exhaust passage 12 or the intake passage. 11 is set so as to block communication with the circumferential groove portion 27a of the valve lifter 23 in the process of closing the intake port portion 11 (see FIG. 4B).

  When the valve head 21 closes the exhaust port portion of the exhaust passage 12 and the intake port portion of the intake passage 11, the head portion of the valve lifter 23 protrudes outward from the valve lifter holding portion 16 (see FIGS. 2 and 4C). The peripheral groove portion 27 a of the head is released from the valve lifter holding portion 16 and exposed to the space in the cylinder head 13. Therefore, the lubricating oil as the cooling oil in the hollow portion 26 that flows to the valve stem end side due to inertia is discharged from the circumferential groove portion 27a to the space in the cylinder head 13 through the shaft hole portion 27c and the through hole portion 27b. Is done. The lubricating oil discharged from the circumferential groove portion 27a is collected in an oil pan (not shown) in the cylinder head 13.

  Next, the operation of the cooling device will be described. During engine operation, the valve lifter 23 of the valve 20 is directly driven by the cam 14 a of the cam device 14, and the valve head 21 opens and closes the intake port portion of the intake passage 11 communicating with the combustion chamber 10 and the exhaust port portion of the exhaust passage 12. . When the valve head 21 opens the intake port of the intake passage 11 and the exhaust port of the exhaust passage 12, as shown in FIGS. 1 and 4A, the valve lifter 23 is pushed by the cam 14a and the valve lifter holding portion 16 is pushed. The circumferential groove portion 27a is located at the position of the supply groove 18 by sliding in the direction of entry, and the circumferential groove portion 27a and the supply groove 18 are in communication with each other, so that the lubricating oil in the oil reservoir 17 flows from the supply groove 18 It is supplied into the hollow portion 26 through the circumferential groove portion 27a, the through hole portion 27b, and the shaft hole portion 27c. The lubricating oil supplied into the hollow portion 26 flows toward the valve head 21 due to its inertia, and takes heat away from the valve head 21 exposed to the high-temperature combustion gas flowing into the exhaust passage 12 from the combustion chamber 10. Thereby, the valve head 21 is cooled. As the valve head 21 closes the intake port of the intake passage 11 and the exhaust port of the exhaust passage 12, the cam 14a escapes from the head of the valve lifter 23 as shown in FIG. 25, when the valve lifter 23 is slid in the valve lifter holding portion 16 in the direction of coming out of the valve lifter holding portion 16, the circumferential groove portion 27a is detached from the supply groove 18, and the communication between the circumferential groove portion 27a and the supply groove 18 is cut off. Lubricant supply stops. Thereafter, when the valve head 21 closes the intake port portion of the intake passage 11 and the exhaust port portion of the exhaust passage 12, the head of the valve lifter 23 is moved by the valve spring 25 as shown in FIGS. 2 and 4C. Projecting from the holding portion 16, the circumferential groove portion 27 a is released from the valve lifter holding portion 16 and exposed to the space in the cylinder head 13. At this time, the lubricating oil that has taken heat away from the valve head 21 and has flowed to the valve stem end side due to inertia is transferred from the hollow portion 26 to the inside of the cylinder head 13 through the shaft hole portion 27c, the through hole portion 27b, and the circumferential groove portion 27a. After being discharged into the space, it is collected in an oil pan (not shown) in the cylinder head 13 and sent to the oil reservoir 17 again.

  As described above, according to the cooling device of this embodiment, the hollow portion 26 in the valve stem 22 is only one, and the lubricating oil supply / discharge port is only one place in the circumferential groove portion 27a, and the structure is extremely high. In addition to being simple and easy to manufacture and assembling, the manufacturing cost can be reduced. In addition, the valve lifter 23 and the valve lifter holding portion 16 are provided with an intake port 11 and an exhaust passage 12 of the intake passage 11 by the valve 20 (valve head 21). In conjunction with the opening / closing operation of the exhaust port portion, the function as a control valve for controlling the communication between the supply groove 18 and the circumferential groove portion 27a and the cutoff (supply of lubricating oil as cooling oil, supply stop, discharge) Therefore, it is not necessary to equip a dedicated control valve for supplying, stopping and discharging the lubricating oil, so that the apparatus is not complicated and the number of parts is not increased, so that the manufacturing cost is not increased. In See, also high reliability, maintenance is easy.

  Also, unlike the method of cooling by always flowing the lubricating oil, when the valve 20 (valve head 21) needs to be cooled in conjunction with the operation of the engine (particularly, the combustion gas is discharged from the combustion chamber 10 to the exhaust passage 12). Since the lubricating oil is supplied into the hollow portion 26 of the valve 20 when the valve head 21 is exposed to the combustion gas), the amount of the lubricating oil can be minimized. In the case of cooling by always flowing the lubricating oil, the flow rate of the lubricating oil is set in accordance with the time when the cooling is most necessary (when the valve head 21 is exposed to the high-temperature combustion gas). Since it is necessary to always flow the lubricating oil into the circulation path of the cooling device including the valve 20, a large amount of lubricating oil is required as a whole, but such a large amount of lubricating oil is not required. In other words, even with the minimum amount of lubricating oil, it is possible to have the same cooling capacity as when a large amount of lubricating oil is constantly circulated. Further, a special device for flowing a large amount of lubricating oil in the circulation path of the cooling device including the valve 20 at all times is not required.

  Further, the valve 20 that opens and closes the exhaust passage 12 has a valve stem end side located below the valve head 21, so that the valve 20 is hollow when the exhaust passage 12 is closed, as shown in FIGS. When the lubricating oil is discharged from the portion 26, this discharge can be performed smoothly.

  Although one embodiment of the valve cooling device of the present invention has been described with reference to FIGS. 1 to 4, the present invention is not limited to that shown in this embodiment, and various modifications can be made within the scope of the claims. Is possible.

  For example, although the case where two through hole portions 27b and one shaft hole portion 27c are provided in the valve lifter 23 is shown, the number of the through hole portions 27b and the shaft hole portions 27c may be changed by tuning.

It is sectional drawing at the time of valve lift which shows one embodiment of the cooling device of the valve | bulb of this invention. It is sectional drawing at the time of valve closing which shows one embodiment of the cooling device of the valve | bulb of this invention. The valve lifter provided with the supply / discharge passage in FIGS. 1 and 2 is shown, (A) is an enlarged plan view of the valve lifter, and (B) is an enlarged vertical sectional view of the same. FIG. 4 is a sectional view for explaining the operation of the valve cooling device, in which (A) is a sectional view for explanation when the valve is lifted, (B) is a sectional view for explanation while the valve is closed, and (C) is a sectional view for explanation when the valve is closed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Combustion chamber 11 Intake passage 12 Exhaust passage 13 Cylinder head 14 Cam apparatus 15 Valve stem guide 16 Valve lifter holding part 17 Oil reservoir 18 Supply passage (supply groove)
20 Valve 21 Valve head 22 Valve stem 23 Valve lifter 24 Retainer 25 Valve spring 26 Hollow portion 27 Supply / discharge passage 27a Circumferential groove portion 27b Through hole portion 27c Shaft hole portion

Claims (3)

A cooling device driven by a cam to cool a valve that opens and closes an intake / exhaust passage connected to a combustion chamber of an engine with cooling oil,
A hollow portion extending from the valve stem end of the valve to the valve head is provided inside the valve stem of the valve,
The valve stem end is provided with a valve lifter driven by the cam, and the valve lifter is provided with a supply / discharge passage for supplying cooling oil to the hollow portion and discharging the cooling oil from the hollow portion,
The valve lifter holding portion disposed in the cylinder head of the engine that holds the valve lifter so as to slide and rotate is provided with a supply passage for supplying the cooling oil to the hollow portion through the supply / discharge passage,
When the valve lifter is driven by the cam and slides within the valve lifter holding portion, the cooling oil is supplied from the supply passage to the hollow portion via the supply / discharge passage, and the supply / discharge passage is A cooling device for a valve, wherein the cooling oil is discharged from the hollow portion to the outside of the valve. The valve cooling device according to claim 1,
The cooling oil for a valve, wherein the cooling oil is a lubricating oil for lubricating between the valve lifter and the valve lifter holding portion. The valve cooling device according to claim 1 or 2,
Supplying the cooling oil to the hollow part and discharging from the hollow part are:
When the valve head is driven by the cam and the valve head opens the intake / exhaust passage, the valve lifter slides in one direction in the valve lifter holding portion to open the supply passage, and the supply passage is connected to the supply / discharge passage. When the cooling oil is supplied to the hollow portion and the valve head closes the intake / exhaust passage, the valve lifter slides in the valve lifter holding portion in the other direction to close the supply passage; The valve cooling apparatus according to claim 1, wherein the supply / discharge passage projects from the valve lifter holding portion, and the cooling oil in the hollow portion is discharged to the outside of the valve via the supply / discharge passage.

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