JP2011012619A - Oil jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil jet having a simple internal structure and a low manufacturing cost capable of cooling a piston when an engine is warm and preventing excessive cooling of the piston when the engine is cold.SOLUTION: The oil jet 40 includes a body part 41 and a nozzle 42 connected with each other. In a hollow part 43 of the body part 41, a first valve mechanism comprising a spherical first valve element 52 and a coil-like first spring 53 and opening and closing an oil inflow hole 47, and a second valve mechanism comprising a coil-like second spring 55 and a coil-like biasing spring 56 comprising a substantially cylindrical second valve element 54 and a shape memory alloy and opening and closing an oil outflow hole 50 are provided. At high temperatures, the second spring 55 opens the oil outflow hole 50 by biasing the second valve element 54 in the opening direction of the oil outflow hole 50. At low temperatures, the second spring 55 is contracted by biasing force of the biasing spring 56 acting on the second valve element 54, and the oil outflow hole 50 is closed by the second valve element 54.

Description

  The present invention relates to an oil jet that cools a piston by spraying oil onto the back surface of the piston of an internal combustion engine.

  Generally, in a reciprocating internal combustion engine (engine), if the piston is overheated, knocking (abnormal combustion) is likely to occur, and the thermal expansion of the piston eliminates the clearance between the piston and the inner wall of the cylinder, resulting in frictional resistance. Will increase. In addition, repeated overheating and cooling may cause deterioration or damage to the piston crown. For this reason, an internal combustion engine is usually provided with an oil jet (piston cooling device) that cools the piston by spraying engine oil onto the back surface of the piston. The oil passage in the oil jet is provided with a valve mechanism that opens and closes the oil passage according to the pressure (supply hydraulic pressure) of the engine oil (see, for example, Patent Document 1).

Hereinafter, the structure and function of a conventional oil jet for a general internal combustion engine will be described with reference to FIGS.
As shown in FIG. 1, in an ordinary reciprocating internal combustion engine 1, a cylinder 3 is formed on an upper portion of a cylinder block 2, and a piston 4 is fitted into the cylinder 3. The piston 4 is connected to the crankshaft 7 via a connecting mechanism having a connecting rod 5 and a crankpin 6. The cylinder block 2 is provided with a main oil passage 8 (main gear library) and a communication port 9 communicating with the main oil passage 8. And the oil jet 10 provided with the structure as shown in FIG. 2 is attached to the cylinder block 2 by bolt fastening in the form as shown in FIG. Engine oil is supplied to the oil jet 10 from the main oil passage 8.

  As shown in FIG. 2, the oil jet 10 generally includes a main body portion 12 having a hollow portion 11, a nozzle 13 coupled to the main body portion 12, and a valve mechanism disposed in the hollow portion 11. Yes. The valve mechanism includes a valve seat portion 14 formed in the hollow portion 11, a spherical valve body 15 that opens and closes the valve seat portion 14, and a spring 16 that biases the valve body 15 in a direction in which the valve seat 15 is seated on the valve seat portion 14. And a plug member 17 that supports one end of the spring 16 and closes one end of the hollow portion 11.

  Thus, in the internal combustion engine 1, when the oil pressure in the main oil passage 8 becomes equal to or higher than a predetermined value, the spring 16 is compressed and the valve body 15 is opened. As a result, engine oil in the main oil passage 8 is injected from the tip of the nozzle 13. The injected engine oil is sprayed on the back surface of the piston 4, thereby cooling the piston 4.

JP 07-317519 A

  Incidentally, the conventional oil jet 10 shown in FIG. 2 injects engine oil when the internal combustion engine 1 is cold, that is, even when the internal combustion engine 1 is operated in a cold state, if the hydraulic pressure rises above a predetermined value. Thus, it is structured to be sprayed on the back surface of the piston 4. For this reason, when the internal combustion engine 1 is cold, the piston 4 may be in a supercooled state. When the piston 4 is in a supercooled state, the clearance between the piston 4 and the inner wall of the cylinder 3 increases due to insufficient thermal expansion of the piston 4, generating noise and vibration. There arises a problem such as an increase. In addition, when the piston 4 is supercooled, the temperature in the combustion chamber decreases, fuel combustion becomes incomplete, and the exhaust gas temperature does not reach the reaction temperature necessary for exhaust gas purification. Arise.

  Therefore, in the oil jet disclosed in Patent Document 1, overcooling of the piston is prevented by switching the injection form of the engine oil with a thermostat that is sensitive to the temperature of the engine oil. Hereinafter, a mechanism for preventing overcooling of the piston in the oil jet disclosed in Patent Document 1 will be described with reference to FIGS.

  As shown in FIG. 4, an oil jet 20 disclosed in Patent Document 1 includes an oil jet main body 22 having an oil passage 21, a cylinder wall lubrication conduit 23 connected to the oil jet main body 22, and a piston cooling unit. A conduit 24 and a valve mechanism disposed in the oil jet main body 22 are provided. Here, the oil passage 21, the cylinder wall lubricating conduit 23 and the piston cooling conduit 24 are in communication with each other via lateral holes 25 and 26 formed in the wall portion of the oil jet main body 22, respectively. The valve mechanism includes a step portion 27 (seat portion) formed in the oil jet main body 22, a pressure valve 28 that opens and closes the step portion 27, a spring 29 that biases the pressure valve 28 upward, and a thermostat 30. It has. The thermostat 30 supports one end of the spring 29 and closes one end of the oil passage 21.

  As shown in FIG. 5, the thermostat 30 includes a hydraulic sensor chamber 31, a small piston 32 fitted in the hydraulic sensor chamber 31, a spring 33 that urges the small piston 32 upward, a hydraulic sensor chamber 31, and a small piston. And a thermo wax 34 enclosed in a space between the upper surface of 32. The thermo wax 34 expands as the temperature rises, and can move the small piston 32 downward against the urging force of the spring 33. In FIG. 5, d indicates the operating range of the small piston 32 due to expansion / contraction of the thermowax 34.

  As shown in FIG. 6, when the internal combustion engine is warm, the thermo wax 34 expands and moves the small piston 32 downward against the urging force of the spring 33. For this reason, the small piston 32 is completely accommodated in the hydraulic sensor chamber 31. In this case, when the oil pressure in the oil passage 21 exceeds a predetermined value, the pressure valve 28 is moved downward as much as possible by the oil pressure, and the cylinder wall lubricating conduit 23 and the piston cooling conduit 24 communicate with the oil passage 21. . Thereby, engine oil is sprayed on the back surface of the piston, and the piston is cooled.

  On the other hand, when the internal combustion engine is cold, the thermowax 34 is contracted. Therefore, as shown in FIGS. 4 and 5, the small piston 32 protrudes maximally upward. In this case, when the oil pressure in the oil passage 21 becomes equal to or greater than a predetermined value, the pressure valve 28 is moved downward by the oil pressure and opened, but is locked by the small piston 32. 21, but the piston cooling conduit 24 does not communicate with the oil passage 21. For this reason, engine oil is not sprayed on the back surface of the piston, and overcooling of the piston is prevented.

  However, since the conventional oil jet disclosed in Patent Document 1 must be provided with an expensive thermostat as shown in FIG. 5, the internal structure is complicated and the manufacturing cost is high. The present invention was made to solve the above-described conventional problems, and can effectively cool the piston when the internal combustion engine is warm, and can prevent overcooling of the piston when it is cold. An object to be solved is to provide an oil jet having a simple internal structure and low manufacturing cost.

  An oil jet for an internal combustion engine according to the present invention, which has been made to solve the above problems, includes a main body, a nozzle, a first valve mechanism, and a second valve mechanism. The main body is formed with a substantially cylindrical hollow portion, an oil inflow hole formed at one end of the hollow portion as viewed in the direction in which the central axis of the hollow portion extends, and a side portion of the hollow portion. An oil outflow hole through which oil flows out from the hollow portion is formed. Here, the nozzle has an oil passage that is coupled to the main body and communicates with the oil outflow hole. The first valve mechanism opens and closes the oil inflow hole, while the second valve mechanism opens and closes the oil outflow hole.

  In this oil jet, the first valve mechanism includes a spherical first valve body that is housed in the hollow portion and opens and closes the oil inflow hole, and a first spring that urges the first valve body in a direction to close the oil inflow hole. And have. The second valve mechanism includes a second valve body that is accommodated in the hollow portion and opens and closes the oil outflow hole, and a second spring that is formed of a shape memory alloy and engages with the second valve body. At a temperature equal to or higher than the shape recovery temperature (or higher than the shape recovery temperature range), the second valve body is moved in the direction to open the oil outflow hole by the second spring, and the oil outflow hole is opened. On the other hand, at a temperature lower than the shape recovery temperature (or a temperature lower than the shape recovery temperature range), the second spring is caused by an external force (for example, a force generated by a hydraulic pressure difference) in the direction of closing the oil outflow hole acting on the second valve body. While being contracted, the second valve body is moved in a direction to close the oil outflow hole, and the oil outflow hole is closed.

  In the oil jet according to the present invention, the hollow portion has a cylindrical small-diameter portion located on the oil inflow hole side as viewed in the direction in which the central axis extends, and a cylinder having a larger diameter than the small-diameter portion located on the opposite side of the oil inflow hole It is preferable that it is composed of a large-diameter portion having a shape. In this case, it is preferable that the first valve body is accommodated in the small diameter portion. The second valve body is preferably formed in a substantially cylindrical shape and is fitted into the large diameter portion. The oil inflow hole is preferably formed at one end of the small diameter portion. The oil outflow hole is preferably formed in the side portion of the large diameter portion.

  In the oil jet according to the present invention, it is preferable that the large-diameter portion has an opening that opens at an end opposite to the oil inflow hole when viewed in the direction in which the central axis of the hollow portion extends. Moreover, it is preferable that a plug member that closes the opening and supports the ends of the first spring and the second spring is provided. In the oil jet according to the present invention, it is preferable that the second valve mechanism includes a biasing spring that applies an external force in a direction to close the oil outflow hole to the second valve body.

  The oil jet according to the present invention is provided with a second valve mechanism having a simple structure having a second valve body that opens and closes an oil outflow hole and a second spring formed of a shape memory alloy to a conventional ordinary oil jet. With this simple structure, the piston can be effectively cooled when the internal combustion engine is warm, and overcooling of the piston can be prevented when it is cold. Therefore, according to the oil jet of the present invention, there is no need to provide a thermostat or a heat sensitive actuator that is expensive and has a complicated structure. For this reason, the manufacturing cost of an oil jet can be lowered.

It is a partial cross section elevation view of a cylinder block and a piston of an internal combustion engine. It is side surface sectional drawing of the conventional oil jet. It is a partial cross section elevation of a cylinder block and piston of an internal combustion engine provided with the conventional oil jet. It is side surface sectional drawing of the oil jet disclosed by patent document 1, and has shown the state at the time of cold. FIG. 5 is an enlarged sectional elevation view of a thermostat constituting the oil jet shown in FIG. 4. It is side surface sectional drawing of the oil jet disclosed by patent document 1, and has shown the state at the time of warm. It is a perspective view of the oil jet concerning Embodiment 1 of the present invention. It is a perspective view of the oil jet shown in Drawing 7 in the state where a main-body part was removed. It is a perspective view which decomposes | disassembles and shows the oil jet shown in FIG. It is a partial cross section perspective view which decomposes | disassembles and shows the oil jet shown in FIG. It is side surface sectional drawing of the oil jet which concerns on Embodiment 1 of this invention, and has shown the state at the time of cold. It is side surface sectional drawing of the oil jet which concerns on Embodiment 1 of this invention, and has shown the state when supply hydraulic pressure is low at the time of warm. It is side surface sectional drawing of the oil jet which concerns on Embodiment 1 of this invention, and has shown the state when supply hydraulic pressure is high at the time of warm. It is side surface sectional drawing of the oil jet which concerns on Embodiment 2 of this invention, and has shown the state when the internal combustion engine has stopped. It is side surface sectional drawing of the oil jet which concerns on Embodiment 2 of this invention, and has shown the state immediately after starting an internal combustion engine with a cold machine state. It is side surface sectional drawing of the oil jet which concerns on Embodiment 2 of this invention, and has shown the state when some time passes, after starting an internal combustion engine in a cold state. It is side surface sectional drawing of the oil jet which concerns on Embodiment 2 of this invention, and has shown the state when supply hydraulic pressure is low at the time of warm. It is side surface sectional drawing of the oil jet which concerns on Embodiment 2 of this invention, and has shown the state when supply hydraulic pressure is high at the time of warm.

  Hereinafter, embodiments for carrying out the present invention (embodiments 1 and 2) will be described in detail with reference to FIGS. The internal combustion engine (engine) to which the oil jet according to the first and second embodiments of the present invention is mounted is substantially the same as the conventional internal combustion engine shown in FIG. FIG. 1 will be referred to as appropriate.

(Embodiment 1)
As shown in FIGS. 7 to 10, the oil jet 40 according to the first embodiment of the present invention is provided with a main body 41 (body) that forms the base, and a nozzle 42 is brazed to the main body 41 by brazing or the like. It is joined. The main body 41 is formed with a substantially cylindrical hollow 43 serving as an engine oil passage and a cylindrical bolt hole 44 for bolting the oil jet 40 to the cylinder block 2. Here, the hollow portion 43 includes a cylindrical small-diameter portion 45 and a cylindrical large-diameter portion 46 having a larger diameter than the small-diameter portion 45. In the following, for the sake of convenience, regarding the positional relationship in the oil jet 40, the side on which the small diameter portion 45 is located is referred to as “upper” and the large diameter portion 46 is positioned in the direction in which the central axis of the substantially cylindrical hollow portion 43 extends. The side to do is called "down".

  The main body 41 has a cylindrical oil inflow hole 47 that communicates with the small diameter portion 45 and opens at the upper end surface of the main body 41, and a cylindrical opening that communicates with the large diameter portion 46 and opens at the lower end surface of the main body 41. A portion 48 is formed. Here, the oil inflow hole 47 has a smaller diameter than the small diameter portion 45, and the opening 48 has a larger diameter than the large diameter portion 46. A tapered valve seat 49 is formed at the boundary between the small diameter portion 45 and the oil inflow hole 47. The main body 41 has a substantially cylindrical shape whose central axis extends in the horizontal direction, that is, in a direction perpendicular to the vertical direction, one end communicates with the large diameter portion 46 and the other end opens on the peripheral surface of the main body 41. An oil outflow hole 50 is formed. The nozzle 42 is inserted into a part (large diameter part) of the oil outflow hole 50 and joined to the main body 41. An oil passage 51 that penetrates the nozzle 42 in the longitudinal direction is formed in the nozzle 42, and the oil passage 51 passes through a portion (small diameter portion) of the oil outflow hole 50 to form a large diameter portion 46 or a hollow portion. 43 is in communication.

  In the hollow portion 43, a first valve mechanism configured by a spherical first valve body 52 (ball valve) and a coiled first spring 53 (coil spring) and opening and closing the oil inflow hole 47, and a substantially cylindrical shape. The second valve body 54 (cylindrical valve member), a coiled second spring 55 (SMA spring) made of a shape memory alloy, and a coiled biasing spring 56 (bias spring) open and close the oil outflow hole 50. A second valve mechanism is provided. The lower end of the hollow portion 43 or the large diameter portion 46 is closed by a plug member 57. The plug member 57 is fitted into the opening 48 and is fixed to the main body 41 by, for example, caulking. The first valve mechanism operates according to the oil pressure, and the second valve mechanism operates according to the oil temperature, but the operations of both are independent of each other.

  In the first valve mechanism, the first valve body 52 is accommodated in the small diameter portion 45 and is always urged upward by the first spring 53. The first spring 53 is disposed across the small diameter portion 45 and the large diameter portion 46, the upper end portion thereof supports the first valve body 52, and the lower end portion thereof is supported by the plug member 57. Note that the first spring 53 is positioned in the lateral direction by the protrusion 57 b of the plug member 57. If the pressure of the engine oil in the main oil passage 8, that is, the hydraulic pressure applied to the oil inflow hole 47 (hereinafter referred to as “supply hydraulic pressure”) is less than a predetermined set pressure (hereinafter referred to as “valve opening pressure”), the first valve The body 52 is seated on a valve seat portion 49 formed at the boundary between the small diameter portion 45 and the oil inflow hole 47 by the urging force of the first spring 53, and the oil inflow hole 47 is closed. On the other hand, if the supply hydraulic pressure is equal to or higher than the valve opening pressure, the first valve body 52 is moved downward against the biasing force of the first spring 53 by the supply hydraulic pressure, and the oil inflow hole 47 is opened.

  In the second valve mechanism, the substantially cylindrical second valve body 54 is fitted into the cylindrical large-diameter portion 46. The second valve element 54 can basically move upward until the upper end of the second valve element 54 comes into contact with the stepped portion 59 (stopper) between the small diameter portion 45 and the large diameter portion 46. . On the other hand, the lower end portion can move downward until it contacts the upper end portion of the edge portion 57 a of the plug member 57. Here, when the second valve body 54 is positioned on the upper side, the oil outflow hole 50 is opened (see FIG. 12). On the other hand, when the second valve body 54 is positioned on the lower side, the oil outflow hole 50 is closed by the peripheral wall of the second valve body 54 (see FIG. 11).

  The second spring 55 is a helical spring (coil spring) formed of a shape memory alloy, for example, a Ni—Ti alloy, and is in a state higher than the shape recovery temperature (transformation temperature) or the shape recovery temperature range (hereinafter “high temperature”). When in the “state”, the crystal structure becomes an austenite phase, and a state having a relatively large transverse elastic modulus or shear elastic modulus (hereinafter referred to as “restored state”). On the other hand, when the second spring 55 is in a state lower than the shape recovery temperature or the shape recovery temperature range (hereinafter referred to as “low temperature state”), its crystal structure becomes a martensite phase, and its transverse elastic modulus decreases, This is a state that is very easy to compress and deform compared to the restored state (hereinafter referred to as “easy deformation state”). Since the downward movement of the second valve body 54 is locked by the edge 57a of the plug member 57, excessive compression deformation of the second spring 55 is prevented. The second spring 55 is preferably formed so that when it is compressed and deformed in an easily deformable state, this deformation is maintained unless it becomes a high temperature state again.

  The biasing spring 56 has a small diameter so that the upper end of the biasing spring 56 abuts on the stepped portion 60 between the small diameter portion 45 and the oil inflow hole 47, and the lower end thereof abuts on the upper end of the second valve body 54. The portion 45 or the large diameter portion 46 is disposed. The biasing spring 56 always biases the second valve body 54 downward. Here, the urging force of the urging spring 56 can position the second valve body 54 in a portion (maximum upper side) in contact with the stepped portion 59 in the high temperature state, while compressing the second spring 55 in the low temperature state. Thus, the second valve body 54 is preferably set so that the second valve body 54 can be positioned at a portion (maximum lower side) in contact with the edge 57a of the plug member 57.

Hereinafter, the operation | movement thru | or function of the oil jet 40 which concerns on Embodiment 1 shown in FIGS. 7-10 is demonstrated concretely, referring FIGS.
As shown in FIG. 11, when the internal combustion engine 1 is cold, that is, when the second spring 55 is in a low temperature state, the second spring 55 is in an easily deformable state due to a decrease in the transverse elastic coefficient. Therefore, the urging force of the urging spring 56 causes the second valve body 54 to move downward until it abuts against the urging force of the second spring 55 and abuts against the upper end portion of the edge portion 57 a of the plug member 57. As a result, the oil outflow hole 50 is closed by the peripheral wall of the second valve body 54, and the engine oil cannot enter the oil passage 51 of the nozzle 42 from the hollow portion 43.

  In this state, the engine oil cannot flow from the main oil passage 8 into the oil jet 40 even if the supply hydraulic pressure is equal to or higher than the valve opening pressure. For this reason, engine oil is not injected from the nozzle 42 of the oil jet 40 to the back surface of the piston 4, and overcooling of the piston 4 when the internal combustion engine 1 is cold is prevented.

  As shown in FIG. 12, when the internal combustion engine 1 is warm, that is, when the second spring 55 is in a high temperature state, the second spring 55 is in a restored state due to an increase in its lateral elastic modulus. Therefore, the second valve body 54 is moved upward by the biasing force of the second spring 55 until it abuts against the stepped portion 59 against the biasing force of the biasing spring 56. As a result, the oil outflow hole 50 is opened, and the engine oil can flow into the oil passage 51 of the nozzle 42 from the hollow portion 43.

  Even if the oil outflow hole 50 is thus opened, if the supply hydraulic pressure is less than the valve opening pressure, the first valve body 52 is pressed against the valve seat portion 49 by the urging force of the first spring 53, and the valve seat portion 49. At this time, the communication between the oil inflow hole 47 (main oil passage 8) and the small diameter portion 45 is completely blocked by the first valve body 52. Therefore, engine oil is not supplied from the main oil passage 8 to the oil jet 40, and engine oil is not injected from the nozzle 42 of the oil jet 40 to the back surface of the piston 4.

  On the other hand, as shown in FIG. 13, when the supply oil pressure is equal to or higher than the valve opening pressure when the internal combustion engine 1 is warm, that is, when the second spring 55 is in a high temperature state, the supply oil pressure causes the first spring 53 to The first valve body 52 is appropriately moved downward against the urging force and separated from the valve seat portion 49. At this time, the oil inflow hole 47 (main oil passage 8) and the small diameter portion 45 communicate with each other. Therefore, engine oil is supplied from the main oil passage 8 to the oil jet 40, and this engine oil is injected from the nozzle 42 of the oil jet 40 to the back surface of the piston 4. Thereby, overheating of the piston 4 is prevented, and occurrence of problems such as knocking, an increase in frictional resistance between the piston 4 and the inner wall of the cylinder 3, or deterioration or damage of the crown portion of the piston 4 is prevented.

  Thus, according to the oil jet 40 according to the first embodiment, for example, a conventional ordinary oil jet as shown in FIG. 2 is attached to the second valve body 54 and the second spring 55 that open and close the oil outflow hole 50. It is possible to effectively cool the piston 4 when the internal combustion engine 1 is warm, and to prevent the piston 4 from being overcooled when it is cold, simply by adding a second valve mechanism having a simple structure including the spring 56. Can do. Therefore, for example, it is not necessary to provide an expensive thermostat or a thermal actuator having a complicated structure as shown in FIG. 5, so that the manufacturing cost of the oil jet 40 can be reduced.

(Embodiment 2)
Hereinafter, an oil jet according to Embodiment 2 of the present invention will be described. However, the configuration of the oil jet 40 ′ according to the second embodiment is substantially the same as the configuration of the oil jet 40 according to the first embodiment shown in FIGS. 7 to 10 except that the biasing spring 56 is not provided. . Therefore, the difference from the oil jet 40 according to the first embodiment will be mainly described below.

  In the oil jet 40 ′ according to the second embodiment, the urging spring 56 that constantly urges the second valve body 54 downward is not provided. For this reason, when the internal combustion engine 1 is cold, that is, when the second spring 55 is in a low temperature state, the hydraulic pressure difference between the upper side and the lower side of the second valve body 54 in the hollow portion 43, that is, the flow direction of the engine oil. Accordingly, a downward force is applied to the second valve body 54 due to a hydraulic pressure difference between the upstream side and the downstream side of the second valve body 54, and the second valve body 54 is moved downward to cause the edge 57 a of the plug member 57. It is made to contact | abut to the upper end part. The urging force of the second spring 55 in the low temperature state is preferably set so as to be smaller than the hydraulic pressure difference between the upper side and the lower side of the second valve body 54. About another point, it is the same as that of the oil jet 40 which concerns on Embodiment 1. FIG.

Hereinafter, the operation or function of the oil jet 40 ′ according to the second embodiment will be specifically described with reference to FIGS. 14 to 18.
As shown in FIG. 14, when the internal combustion engine 1 is stopped, no oil pressure is introduced into the oil jet 40 ′, so the first valve body 52 is in a closed state. On the other hand, since the second spring 55 is in a high temperature state when the internal combustion engine 1 is stopped, the second valve body 54 is positioned at the top in the large diameter portion 476 and is in a valve open state. After this, even if the temperature of the internal combustion engine 1 is lowered and the second spring 55 is in a low temperature state, no downward force is applied to the second valve body 54 except for gravity, so the position of the second valve body 54 Does not change. That is, the state shown in FIG. 14 is maintained until the internal combustion engine 1 is stopped and then started again.

  As shown in FIG. 15, when the internal combustion engine 1 is started in a cold state, the pressure (supply hydraulic pressure) of the engine oil having a low temperature and high viscosity in the main oil passage 8 is supplied through the oil inflow hole 47 to the first valve body. Acts on 52. And if supply hydraulic pressure becomes more than a valve opening pressure, the 1st valve body 52 will be in a valve opening state. On the other hand, since the second valve body 54 is in the open state at this time, the engine oil in the main oil passage 8 flows through the hollow portion 43 and flows out to the oil passage 51 of the nozzle 42.

  Thus, when engine oil having a low temperature and high viscosity flows downward in the hollow portion 43, the hydraulic pressure on the upper side or the upstream side of the second valve body 54 in the hollow portion 43 is below or on the second valve body 54. It is considerably higher than the hydraulic pressure on the downstream side. Thus, a downward force is applied to the second valve body 54 due to the hydraulic pressure difference between the upper side and the lower side of the second valve body 54. At this time, since the second spring 55 is in a low temperature state, that is, in an easily deformable state, the upward biasing force of the second spring 55 is very small. For this reason, the second valve element 54 easily moves downward.

  Thus, as shown in FIG. 16, the second valve element 54 contacts the upper end of the edge 57 a of the plug member 57 and closes the oil outflow hole 50. That is, the second valve body 54 or the second valve mechanism is closed. Here, when the second valve body 54 moves upward for some reason and a gap is generated between the second valve body 54 and the oil outflow hole 50, the engine oil in the hollow portion 43 flows into the oil passage of the nozzle 42. It flows out to 51.

  At this time, a hydraulic pressure difference is generated between the upper side and the lower side of the second valve body 54 in the hollow portion 43 due to the flow of the engine oil. Then, the second valve body 54 moves downward due to this hydraulic pressure difference and closes the oil outflow hole 50, so that the second valve body 54 or the second valve mechanism is closed again. Therefore, when the internal combustion engine 1 is cold after the start, the second valve body 54 or the second valve mechanism substantially remains in the closed state. In this way, when the internal combustion engine 1 is cold, the engine oil is not injected from the nozzle 42 of the oil jet 40 ′ to the back surface of the piston 4, so that overcooling of the piston 4 is prevented.

  As shown in FIG. 17, when the internal combustion engine 1 is warmed up after a certain period of time after the internal combustion engine is started, that is, when it is warm, the ambient temperature of the second spring 55 rises, and the second spring 55 becomes a high temperature state. Accordingly, the second spring 55 is restored by increasing its lateral elastic modulus. For this reason, the second valve body 54 is moved upward by the urging force of the second spring 55 until it abuts against the stepped portion 59. As a result, the oil outflow hole 50 is opened, and the oil can flow into the oil passage 51 of the nozzle 42 from the hollow portion 43. FIG. 17 shows a state where the supply hydraulic pressure is less than the valve opening pressure. Therefore, although the oil outflow hole 50 is opened, the engine oil is not supplied from the main oil passage 8 to the oil jet 40 ′ because the first valve mechanism or the first spring 53 is closed, and the oil jet 40 ′. No engine oil is injected from the nozzle 42 to the back surface of the piston 4.

  Here, as shown in FIG. 18, when the supply hydraulic pressure becomes equal to or higher than the valve opening pressure, the first valve body 52 moves moderately downwardly against the biasing force of the first spring 53 by this supply hydraulic pressure. It is made to move away from the valve seat part 49. Therefore, engine oil is supplied from the main oil passage 8 to the oil jet 40 ′, and engine oil is injected from the nozzle 42 of the oil jet 40 ′ to the back surface of the piston 4. In this state, the engine oil is in a state where the temperature is high and the viscosity is low, so that a large hydraulic pressure difference does not occur between the upper side and the lower side of the second valve body 54 in the hollow portion 43. Therefore, the second valve body 54 does not move downward due to the hydraulic pressure difference. Thus, overheating of the piston 4 when the internal combustion engine 1 is warm is prevented, and problems such as knocking, an increase in frictional resistance between the piston 4 and the inner wall of the cylinder 3, or deterioration or damage of the crown of the piston 4 are caused. Is prevented from occurring.

  As described above, according to the oil jet 40 ′ according to the second embodiment, the second valve body 54 and the second spring 55 that open and close the oil outflow hole 50, for example, a conventional ordinary oil jet as shown in FIG. The piston 4 can be effectively cooled when the internal combustion engine 1 is warm, and overcooling of the piston 4 can be prevented when it is cold. Therefore, for example, it is not necessary to provide an expensive thermostat or a thermal actuator having a complicated structure as shown in FIG. 5, so that the manufacturing cost of the oil jet 40 'can be reduced. Further, since the biasing spring 56 is not provided, the structure can be further simplified and the manufacturing cost can be further reduced as compared with the oil jet 40 according to the first embodiment.

  DESCRIPTION OF SYMBOLS 1 Internal combustion engine (engine), 2 cylinder block, 3 cylinder, 4 piston, 5 connecting rod, 6 crankpin, 7 crankshaft, 8 main oil passage (main gallery), 9 communication port, 10 oil jet, 11 hollow part, 12 Body, 13 Nozzle, 14 Valve seat (valve seat), 15 Valve body (ball valve), 16 Spring, 17 Plug member, 20 Oil jet, 21 Oil passage, 22 Oil jet body, 23 Cylinder wall lubrication conduit , 24 Piston cooling conduit, 25 Horizontal hole, 26 Horizontal hole, 27 Step part, 28 Pressure valve, 29 Spring, 30 Thermostat, 31 Hydraulic sensor chamber, 32 Small piston, 33 Spring, 34 Thermo wax, 40 Oil jet (Embodiment 1) 40 'oil jet Embodiment 2), 41 Main body, 42 Nozzle, 43 Hollow part, 44 Bolt hole, 45 Small diameter part, 46 Large diameter part, 47 Oil inflow hole, 48 Opening part, 49 Valve seat part, 50 Oil outflow hole, 51 Oil Passage, 52 1st valve body, 53 1st spring, 54 2nd valve body, 55 2nd spring, 56 Energizing spring, 57 Plug member, 57a Edge, 57b Projection part, 59 Step part, 60 Step part.

Claims (4)

A substantially cylindrical hollow portion; an oil inflow hole formed at one end of the hollow portion as viewed in the direction in which the central axis of the hollow portion extends; and an oil inflow hole through which oil flows into the hollow portion; A main body portion formed with an oil outflow hole for allowing oil to flow out of the hollow portion;
A nozzle coupled to the body portion and having an oil passage communicating with the oil outflow hole;
A first valve mechanism for opening and closing the oil inflow hole;
An oil jet for an internal combustion engine comprising a second valve mechanism for opening and closing the oil outflow hole,
The first valve mechanism includes a spherical first valve body that is accommodated in the hollow portion and opens and closes the oil inflow hole, and a first spring that urges the first valve body in a direction to close the oil inflow hole. Have
The second valve mechanism includes a second valve body that is accommodated in the hollow portion and opens and closes the oil outflow hole, and a second spring that is formed of a shape memory alloy and engages with the second valve body,
At a temperature equal to or higher than the shape recovery temperature, the second valve body is moved in the direction to open the oil outflow hole by the second spring,
At a temperature lower than the shape recovery temperature, the second spring is contracted by an external force in the direction of closing the oil outflow hole acting on the second valve body, and the second valve body closes the oil outflow hole. An oil jet that is moved in the direction. The hollow portion has a cylindrical small-diameter portion located on the oil inflow hole side in the direction in which the central axis extends, and a cylindrical large-diameter located opposite to the oil inflow hole and larger in diameter than the small-diameter portion. And consists of
The first valve body is accommodated in the small diameter portion,
The second valve body is formed in a cylindrical shape and is fitted into the large diameter portion,
The oil inflow hole is formed at one end of the small diameter portion,
The oil jet according to claim 1, wherein the oil outflow hole is formed in a side portion of the large diameter portion. The large-diameter portion has an opening that opens at an end opposite to the oil inflow hole as viewed in the direction in which the central axis of the hollow portion extends,
3. The oil jet according to claim 1, wherein a plug member that closes the opening and supports ends of the first spring and the second spring is provided. 4.   The said 2nd valve mechanism is provided with the urging | biasing spring which makes the said 2nd valve body act on the said 2nd valve body with the external force of the direction which closes the said oil outflow hole. Oil jet.

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