JP2013249742A - Oil jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil jet in which injection-valve opening pressure is mechanically and automatically adjusted according to the oil temperature.SOLUTION: A body 2 of an oil jet 100 is provided with: an oil supply port 6 opened in an oil passage 62; a cylinder 4 whose one end communicates with the oil supply port 6 while whose the other end is closed; and an oil injection port 10 opened in the side surface of the cylinder 4. A piston valve 20 is housed in the cylinder 4. The piston valve 20 forms a differential pressure chamber 8, being a closed section, in the cylinder 4. The differential pressure chamber 8 communicates with the oil supply port 6 via an orifice 22 provided in the piston valve 2. A groove 24 communicating with the differential pressure chamber 8 is formed in the outer peripheral surface of the piston valve 20. The piston valve 20 is biased to a position to close the oil injection port 10 by a first spring 16 and a second spring 18. Further, the body 2 is formed with a leak hole 42 for leaking oil to the outside of the body 2 from the differential pressure chamber 8.

Description

  The present invention relates to an oil jet used for cooling a piston of an internal combustion engine.

  An oil passage through which pressurized oil flows is formed in the cylinder block of the internal combustion engine. The oil jet is a device that injects oil supplied from the oil passage between the piston and the piston and the cylinder bore, and thereby cools the piston that has become hot. Conventionally used oil jets have a mechanism for opening and closing a valve in accordance with hydraulic pressure. Specifically, the valve body is biased by a spring in a direction against the hydraulic pressure, and when the force received by the hydraulic pressure exceeds the force of the spring, the valve body separates from the valve seat and the valve opens. It is like that. While the hydraulic pressure increases as the rotational speed of the internal combustion engine increases, the piston temperature increases as the rotational speed increases. Therefore, according to the above mechanism, oil is injected to cool the piston while the piston is hot. In a situation where the temperature of the piston is not high, overcooling can be prevented by stopping oil injection.

  The oil jet described in Patent Document 1 below also includes a spring mechanism for opening and closing a valve in accordance with hydraulic pressure. The oil jet further has a mechanism for changing the oil injection amount in accordance with the oil temperature. The mechanism is a throttle member disposed upstream of the valve. A plurality of aperture holes are formed in the aperture member. When passing through these throttle holes, the oil is subjected to flow resistance, and its magnitude increases as the viscosity of the oil increases. For this reason, when the temperature of the oil is low and the viscosity of the oil is high, the flow rate of the oil passing through the throttle hole decreases. When the temperature of the oil is high and the viscosity of the oil is low, the flow rate of oil passing through the throttle hole increases. With such a mechanism, when the valve is opened due to an increase in hydraulic pressure, the oil injection amount is suppressed because the oil temperature is low if it is cold immediately after the engine is started, and if the oil is warmed up, As the temperature rises, the oil injection amount is increased.

JP 2011-064155 A

  The oil jet described in Patent Document 1 is configured so that its operating state changes not only by oil pressure but also by oil temperature. Since the oil temperature is closely related to the temperature state of the piston as well as the oil pressure, the configuration in which the operating state of the oil jet is switched according to the oil temperature is a general oil that simply opens and closes the valve according to the oil pressure. It is considered that the piston can be cooled more appropriately by the injection of oil than the jet.

  However, there is a problem with the oil jet described in Patent Document 1. In the oil jet described in Patent Document 1, since a throttle member is disposed in the oil flow path, pressure loss occurs when the oil passes through the throttle member. If the oil temperature is high and the viscosity of the oil is low, the generated pressure loss is small, but the pressure loss is large compared to an oil jet without a throttle member. Accordingly, the amount of oil injected to the piston at a high temperature decreases. Furthermore, even if the oil pressure rises, the oil injection amount is suppressed until the oil temperature becomes sufficiently high, so that when the cold internal combustion engine is operated at a high speed, the piston becomes hot. In spite of this, a sufficient amount of oil may not be injected.

  The problems described above can be solved by changing the valve opening pressure when the valve opens according to the oil temperature. That is, if the valve opening pressure can be increased when the oil temperature is low and the valve opening pressure can be decreased as the oil temperature increases, the problem that occurs in each oil jet described in Patent Document 1 does not occur. However, the means is preferably a mechanical oil jet. In the case of an oil jet that opens and closes a valve by a solenoid, the opening and closing of the valve can be electrically operated in accordance with the hydraulic pressure and the oil temperature. However, considering the reliability and cost, a mechanical oil jet is more advantageous.

  This invention is made | formed in view of such a subject, and it aims at providing the oil jet by which valve opening pressure is automatically adjusted automatically according to oil temperature.

  The oil jet according to the present invention includes at least a body, a piston valve, a first spring, and a second spring. The body is an oil jet main body attached to a cylinder block of the internal combustion engine, and has an oil supply port, a cylinder, and an oil injection port. The oil supply port is formed so as to open to an oil passage in the cylinder block when the body is attached to the cylinder block. One end of the cylinder communicates with the oil supply port and the other end is closed. The oil injection port opens on the side of the cylinder.

  The piston valve is accommodated in the cylinder and forms a closed section in the cylinder. The piston valve is formed with an orifice that allows the closed section to communicate with the oil supply port. A groove communicating with the closed compartment is formed on at least a part of the outer periphery of the piston valve. The first spring biases the piston valve toward the oil injection port. The second spring biases the piston valve toward the closed compartment. In the first spring and the second spring, the piston valve is located at a position where the oil injection port is closed when the differential pressure between the pressure in the oil passage and the pressure in the closed compartment is within a predetermined range. The spring length and the spring constant are adjusted so that the groove communicates with the oil injection port when the differential pressure between the pressure in the closed section and the pressure in the closed compartment deviates from the lower limit of the predetermined range.

  Furthermore, in the oil jet according to the present invention, the body is formed with a leak hole through which oil leaks from the closed section in the cylinder to the outside of the body. Various shapes can be employed as the shape of the leak hole. When the oil jet has a columnar stopper that is inserted into the closed compartment from the bottom of the cylinder and passes through the sleeve valve to limit the movement range of the piston valve, a hole and stopper for passing the stopper formed in the body The leak hole can be formed by a gap formed between the side surfaces of the two. The shape of the leak hole in that case can be an annular gap surrounding the stopper.

  According to the above configuration of the oil jet according to the present invention, the oil injection port is opened and closed by the piston valve. On the piston valve, the pressure of the oil flowing through the oil passage in the cylinder block and the urging force of the second spring act, and at the same time, the pressure of the oil in the closed compartment and the first spring are reversed. A biasing force acts. Then, the resultant force of the force received by the piston valve from the hydraulic pressure in the oil passage and the biasing force by the second spring is greater than the resultant force of the force received by the piston valve from the hydraulic pressure in the closed compartment and the biasing force by the first spring. When it becomes larger, the piston valve moves from a position where it is pushed by the oil supplied from the oil passage and closes the oil injection port. As a result, the oil injection port communicates with the oil supply port, and oil is supplied to the oil injection port to achieve oil injection.

  The oil pressure in the closed compartment changes depending on the relationship between the flow rate of oil flowing into the closed compartment through the orifice and the flow rate of oil leaking from the closed compartment through the leak hole. In the oil jet according to the present invention, the orifice and the leak hole are different in factors that determine the flow rate. For orifices where the relationship between flow and pressure follows Bernoulli's theorem, the oil density affects the flow. More specifically, the flow rate of the oil that passes through the orifice and flows into the closed section from the oil injection port side is inversely proportional to the 1/2 power of the oil density. On the other hand, in a leak hole whose flow rate is determined by Hagen-Poiseuille's law, the oil viscosity affects the flow rate. More specifically, the flow rate of oil that passes through the leak hole and leaks from the closed section of the cylinder to the outside of the body is inversely proportional to the oil viscosity. What is important here is that the sensitivity to oil temperature differs greatly between oil density and oil viscosity. There is almost no change in the oil density with respect to the change in the oil temperature, and the oil density can be regarded as almost constant in the normal temperature range of the oil in the internal combustion engine. On the other hand, the change in oil viscosity with respect to the change in oil temperature is extremely large. Although depending on the type of oil, the oil viscosity during cold is 10 times or more higher than the oil viscosity after warm-up. For this reason, when compared with the pressure in the same closed compartment, the flow rate of oil flowing from the orifice into the closed compartment does not vary greatly depending on the oil temperature, but the flow rate of oil leaking from the leak hole increases as the oil temperature increases. To do. The greater the flow rate of oil leaking from the leak hole, the greater the drop in hydraulic pressure in the closed compartment.

  If the position of the piston valve is constant, the urging forces of the first spring and the second spring are constant. Therefore, the hydraulic pressure in the oil passage required to move the piston valve, that is, the valve opening pressure is closed. It depends on the hydraulic pressure in the compartment. When the oil temperature is high, such as after the warm-up is completed, the oil viscosity is low, so that oil easily leaks from the closed compartment, and as a result, the valve opening pressure becomes low because the pressure in the closed compartment becomes low. . On the other hand, when the oil temperature is low as in the cold state, the oil viscosity is high, so that the oil does not easily leak from the closed compartment, and as a result, the pressure in the closed compartment increases and the valve opening pressure also increases. That is, according to the configuration of the oil jet according to the present invention, the valve opening pressure is mechanically automatically adjusted so that the valve opening pressure is lower as the oil temperature is higher and the valve opening pressure is higher as the oil temperature is lower. The

  By the way, under extremely low temperatures, the oil viscosity in the closed compartment may become extremely high, so that oil leakage from the leak hole does not proceed, and the hydraulic pressure in the closed compartment may increase significantly. Excessive rise in oil pressure in the closed compartment can damage the oil jet components. Moreover, since the increase in the hydraulic pressure in the closed compartment prevents the movement of the piston valve in the valve opening direction, there is a possibility that oil injection may not be performed at extremely low temperatures.

  However, according to the above configuration of the oil jet according to the present invention, when the hydraulic pressure in the closed compartment rises greatly, the resultant force of the force received by the piston valve from the hydraulic pressure in the oil passage and the urging force by the second spring is obtained. However, when the resultant force of the force received by the piston valve from the hydraulic pressure in the closed compartment and the urging force of the first spring becomes larger, the piston valve moves toward the oil supply port. As a result, the oil injection port and the closed section communicate with each other through a groove formed in the piston valve. The groove is preferably formed in an annular shape over the entire outer periphery of the piston valve. By doing so, even if the piston valve rotates, the oil injection port and the closed compartment can be reliably communicated. Moreover, it is also preferable that the groove is formed so as to be inclined downward from the outer peripheral side of the piston valve toward the axis side. By doing so, the oil remains in the groove even after the internal combustion engine is stopped, and the remaining oil acts as lubricating oil between the piston valve and the cylinder at the next start-up.

  The oil injection port and the closed compartment communicate with each other through the groove, so that the oil in the closed compartment is discharged from the oil injection port. Since the oil discharged to the oil injection port is injected toward the piston, scuff resistance at an extremely low temperature is ensured. Moreover, since the oil pressure in the closed compartment is reduced by discharging the oil in the closed compartment to the outside, damage to the parts due to excessive increase in the oil pressure is also prevented. Then, the piston valve moves again to the closed section side due to a decrease in the hydraulic pressure in the closed section, and stops at a position where the oil injection port which is a balanced position is closed. Thereby, oil injection through the groove of the piston valve is stopped, and it is possible to prevent unnecessary oil from being injected at an extremely low temperature.

  As described above, according to the oil jet of the present invention, the valve opening pressure can be mechanically automatically adjusted according to the oil temperature. In addition, an appropriate amount of oil can be injected onto the piston while preventing an excessive increase in hydraulic pressure at extremely low temperatures.

It is a longitudinal cross-sectional view which shows typically the structure of the oil jet which concerns on embodiment of this invention. It is the top view and longitudinal cross-sectional view which show the structure of the piston valve of the oil jet which concerns on embodiment of this invention. It is the sectional view on the AA line of FIG. It is a figure for demonstrating operation | movement of the oil jet which concerns on embodiment of this invention. It is a figure for demonstrating operation | movement of the oil jet which concerns on embodiment of this invention. It is a figure for demonstrating operation | movement of the oil jet which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows typically the structure of the modification of the oil jet which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The configuration of the oil jet according to the embodiment of the present invention can be described with reference to FIGS. 1, 2, and 3. As shown in the longitudinal sectional view of FIG. 1, an oil jet 100 according to the present embodiment includes a body 2 attached to a cylinder block 60 of an internal combustion engine. The cylinder block 60 is formed with an oil passage 62 through which oil pressurized by an oil pump flows. Since the oil pump is driven by the power received from the crankshaft of the internal combustion engine, the hydraulic pressure in the oil passage 62 is low when the rotational speed of the internal combustion engine is low, and the hydraulic pressure in the oil passage 62 increases as the rotational speed increases. Go. An oil supply port 6 that opens to the oil passage 62 is formed in the body 2.

  The body 2 is formed with a cylinder 4 having an oil supply port 6 as an inlet. The cylinder 4 is formed through the body 2, and its outlet is covered with a holder 40 described later. Thus, a space is formed in the cylinder 4 where one end is open and the other end is closed. An oil injection port 10 having a smaller diameter than the cylinder 4 is open near the inlet on the side surface of the cylinder 4. An oil injection nozzle 50 is attached to the body 2 by brazing or the like, and an oil injection passage 52 formed in the oil injection nozzle 50 is communicated with the oil injection port 10. The tip of the oil injection nozzle 50 is directed to the back surface of the piston of the internal combustion engine or between the piston and the cylinder bore. Although only one oil injection nozzle 50 is shown in FIG. 1, a plurality of oil injection nozzles 50 may be attached to the body 2 by forming a plurality of oil injection ports 10 in the circumferential direction of the cylinder 4. it can.

  The cylinder 4 houses a piston valve 20 and two springs 16 and 18. A ring-shaped spring seat 14 is attached near the inlet of the cylinder 4. The two springs 16 and 18 are both coiled compression springs. The first spring 16 is disposed between the piston valve 20 and the bottom surface of the cylinder 4 to urge the piston valve 20 toward the inlet side of the cylinder 4, and the second spring 18 is between the piston valve 20 and the spring seat 14. The piston valve 20 is urged toward the bottom surface side of the cylinder 4.

  Further, a stopper 32 for limiting the movement range of the piston valve 20 is provided in the cylinder 4. The stopper 32 has a cylindrical shape and protrudes from the bottom of the cylinder 4 into the cylinder 4. The bottom of the cylinder 4 is formed by a holder 40 embedded in the body 2. A plug 30 integrated with a stopper 32 is fitted in the holder 40, and the stopper 32 is inserted into the cylinder 4 through a hole formed in the holder 40. The holder 40 and the plug 30 are separate pieces from the body 2, but can be regarded as a part of the body 2.

  A closed section 8 surrounded by the piston valve 20 and the side surface and bottom of the cylinder 4 is formed in the cylinder 4. The piston valve 20 is formed with an orifice 22 that allows the closed section 8 to communicate with the oil supply port 6 side. FIG. 2 shows a detailed configuration of the piston valve 20. 2A is a plan view of the piston valve 20 as viewed from above, and FIG. 2B is a cross-sectional view taken along line BB in FIG. Since the orifice 22 is formed in the piston valve 20, when the oil jet 100 is attached to the cylinder block 60, the closed section 8 is filled with oil through the orifice 22. However, a differential pressure with respect to the hydraulic pressure of the oil passage 62 is generated in the hydraulic pressure of the closed section 8 by the action of a leak hole 42 described later. Hereinafter, the closed section 8 is referred to as a differential pressure chamber. The spring lengths and spring constants of the two springs 16 and 18 that support the piston valve 20 are such that the oil injection port when the differential pressure between the pressure in the oil passage 62 and the pressure in the differential pressure chamber 8 is within a predetermined range. The piston valve 20 is adjusted so as to be positioned at a position where the 10 is closed. Here, the spring lengths and spring constants of the two springs 16 and 18 are adjusted so that the piston valve 20 closes the oil injection port 10 when the internal combustion engine in which no oil pressure is generated in the oil passage 62 is stopped. ing.

  In addition, as shown in FIG. 2, an annular groove 24 is formed on the lower half surface of the outer peripheral surface of the piston valve 20 so as to make a full circuit around the outer periphery. The groove 24 is formed to be inclined downward from the outer peripheral side of the piston valve 20 toward the axis side. Further, the piston valve 20 is formed with a communication hole 26 that allows the groove 24 to communicate with the differential pressure chamber 8. In FIG. 2, the communication hole 26 is formed only at one place, but the communication hole 26 may be formed at a plurality of places. The spring lengths and spring constants of the two springs 16 and 18 that support the piston valve 20 are determined when the differential pressure between the pressure in the oil passage 62 and the pressure in the differential pressure chamber 8 deviates from the lower limit of the predetermined range. Further, the piston valve 20 is adjusted to move upward so that the groove 24 and the oil injection port 10 communicate with each other.

  The bottom of the differential pressure chamber 8 is formed by a holder 40, and the holder 40 has a hole for inserting the stopper 32 into the differential pressure chamber 8. A slight gap 42 is formed between the hole and the peripheral surface of the stopper 32. More specifically, as shown in FIG. 3, an annular gap 42 surrounding the stopper 32 is formed. The annular gap 42 is provided to allow oil in the differential pressure chamber 8 to leak out of the body 2, and its cross-sectional area is formed to be much smaller than the cross-sectional area of the differential pressure chamber 8. Yes. Hereinafter, this annular gap is referred to as a leak hole 42. By forming such a leak hole 42 in the body 2, oil leaks out of the body 2 from the differential pressure chamber 8, thereby reducing the hydraulic pressure in the differential pressure chamber 8. That is, a differential pressure is generated between the hydraulic pressure in the oil passage 62 and the hydraulic pressure in the differential pressure chamber 8.

  An oil discharge chamber 44 is formed between the holder 40 and the plug 30 for discharging the oil leaking from the leak hole 42 to the outside. The oil discharge chamber 44 communicates with the outside of the body 2 through a plurality of oil discharge holes 34 formed in the plug 30. The total channel cross-sectional area of the oil discharge hole 34 is much larger than the channel cross-sectional area of the leak hole 42. Therefore, the oil leaked from the leak hole 42 to the oil discharge chamber 44 is quickly discharged out of the body 2 through the oil discharge hole 34 without filling the oil discharge chamber 44 and the oil discharge hole 34.

  Next, the operation of the oil jet 100 according to the present embodiment will be described. In addition, in FIG. 4-6 used for description, the flow of oil in each state is shown by an arrow line.

  FIG. 4 shows the state of the oil jet 100 when the internal combustion engine is stopped. When the internal combustion engine is stopped, no differential pressure is generated between the pressure in the oil passage 62 and the pressure in the differential pressure chamber 8. For this reason, the piston valve 20 stops at a position where the urging force by the first spring 16 and the urging force by the second spring 18 are balanced. Since the stop position of the piston valve 20 at this time is adjusted to a position that closes the oil injection port 10, oil is not discharged from the oil injection nozzle 50 when the internal combustion engine is stopped.

  When the internal combustion engine is started, the oil in the oil passage 62 is pressurized by the oil pump, so that the hydraulic pressure in the oil passage 62 acts on the piston valve 20 from the oil supply port 6 side. In addition, oil flows into the differential pressure chamber 8 through the orifice 22 of the piston valve 20, so that the hydraulic pressure also increases in the differential pressure chamber 8. The resultant force of the oil pressure in the oil passage 62 and the urging force of the second spring 18 acts as a force in the valve opening direction on the piston valve 20, and the force by the oil pressure in the differential pressure chamber 8 and the first spring 16. The resultant force with the urging force acts on the piston valve 20 as a force in a direction that prevents valve opening. When the forces in these two directions act on the piston valve 20, the piston valve 20 moves to a position where the two forces are balanced. Specifically, as the pressure difference between the oil pressure in the oil passage 62 and the oil pressure in the differential pressure chamber 8 increases as the oil pressure in the oil passage 62 increases, the piston valve 20 moves to the bottom side of the cylinder 4. Will be gradually pushed down.

  Then, the pressure difference between the hydraulic pressure in the oil passage 62 and the hydraulic pressure in the differential pressure chamber 8 is further expanded, and the differential pressure between the hydraulic pressure in the oil passage 62 and the hydraulic pressure in the differential pressure chamber 8 is within the predetermined range. When the upper limit is exceeded, the blockage of the oil injection port 10 by the piston valve 20 is released as shown in the schematic diagram of FIG. As a result, the oil injection port 10 and the oil supply port 6 communicate with each other, and oil is supplied to the oil injection port 10 to achieve oil injection from the oil nozzle 50.

The hydraulic pressure in the oil passage 62 at this time, that is, the valve opening pressure is determined by the hydraulic pressure in the differential pressure chamber 8. The hydraulic pressure in the differential pressure chamber 8 varies depending on the relationship between the flow rate of oil entering the differential pressure chamber 8 and the flow rate of oil exiting the differential pressure chamber 8. Since oil flows into the differential pressure chamber 8 through the orifice 22, the flow rate Q 1 is in accordance with Bernoulli's theorem as expressed by the following formula 1. That is, the flow rate Q1 of the oil passing through the orifice 22 is proportional to the square of the differential pressure between the hydraulic pressure P _{M / G} in the oil passage 62 and the hydraulic pressure P _IN in the differential pressure chamber 8, and is 1 of the oil density ρ. / Inversely proportional to the square. In Equation 1, C is a flow coefficient, and A is a flow path cross-sectional area of the orifice 22.

On the other hand, since oil leaks from the differential pressure chamber 8 through the leak hole 42, the flow rate Q2 is in accordance with Hagen-Poiseuille's law as expressed by the following equation 2. That is, the flow rate Q2 of the oil passing through the leak hole 42 is proportional to the differential pressure between the hydraulic pressure P _IN in the differential pressure chamber 8 and the atmospheric pressure P _OUT and inversely proportional to the oil viscosity η. In Equation 2, B is a coefficient.

  As can be seen from the above two equations, the oil density affects the flow rate of oil passing through the orifice 22, but the oil viscosity affects the flow rate of oil passing through the leak hole 42. Oil density and oil viscosity are both affected by oil temperature, but their sensitivity differs greatly. That is, there is almost no change in the oil density with respect to the change in the oil temperature, and the oil density is almost constant in the temperature range from the cold time to the completion of warm-up, whereas the change in the oil viscosity with respect to the change in the oil temperature is extremely large. Although depending on the type of oil, the oil viscosity during cold is 10 times or more higher than the oil viscosity after warm-up.

  Due to the characteristics of the oil density and the oil viscosity with respect to the oil temperature, the flow rate of oil flowing into the differential pressure chamber 8 from the orifice 22 does not vary greatly depending on the oil temperature, but the flow rate of oil leaking from the leak hole 42 is It increases with increasing temperature. The greater the flow rate of oil leaking from the leak hole 42, the lower the oil pressure in the differential pressure chamber 8, and the oil pressure in the oil passage 62 necessary for releasing the blockage of the oil injection port 10 by the piston valve 20, that is, the valve opening. The pressure drops. Therefore, when the oil temperature is high as after the warm-up is completed, the oil is likely to leak from the leak hole 42, so that the valve opening pressure is low. When the oil temperature is low as in the cold time, the leak hole 42 Since the oil is difficult to leak from, the valve opening pressure becomes high. That is, according to the oil jet 100 according to the present embodiment, the valve opening pressure is mechanically automatically adjusted so that the higher the oil temperature is, the lower the pressure is, and the higher the oil temperature is.

  By the way, when the internal combustion engine is started at an extremely low temperature such as −30 ° C., for example, the oil viscosity in the differential pressure chamber 8 becomes extremely high, so that oil leakage from the leak hole 42 does not proceed, and the inside of the differential pressure chamber 8 There is a possibility that the oil pressure of will increase significantly. An excessive increase in the hydraulic pressure in the differential pressure chamber 8 may damage related parts. Moreover, since the increase in the hydraulic pressure in the differential pressure chamber 8 prevents the movement of the piston valve 20 in the valve opening direction, there is a possibility that oil injection may not be performed at extremely low temperatures. When cold, it is desirable to refrain from oil injection in order to prevent overcooling of the piston. However, if there is no oil between the piston and the cylinder bore, the scuff resistance is reduced.

  The idea made in view of the above problems is to form the groove 24 communicating with the differential pressure chamber 8 on the outer peripheral surface of the piston valve 20 and to support the piston valve 20 with the two springs 16 and 18 from above and below. It is.

  When the oil pressure in the differential pressure chamber 8 greatly increases at a very low temperature, according to the configuration of the oil jet 100 according to the present embodiment, the force received by the piston valve 20 from the oil pressure in the oil passage 62 and the second spring Since the resultant force of the force exerted by the first spring 16 and the force received by the piston valve 20 from the hydraulic pressure in the differential pressure chamber 8 becomes larger than the resultant force of the biasing force of 18, the piston valve 20 is connected to the oil supply port 6. Pushed up to the side.

  Since the groove 24 is formed in the lower half surface of the outer peripheral surface of the piston valve 20, when the piston valve 20 is pushed up, the side surface of the cylinder 4 has been blocked up to now as shown in the schematic diagram of FIG. The groove 24 communicates with the oil injection port 10. Since the groove 24 is formed in an annular shape on the entire outer periphery of the piston valve 20, even if the piston valve 20 rotates, the groove 24 always communicates with the oil injection port 10 if the piston valve 20 is pushed up. The piston valve 20 is formed with a communication hole 26 that allows the groove 24 to communicate with the differential pressure chamber 8, so that the groove 24 and the oil injection port 10 communicate with each other through the groove 24. The oil injection port 10 communicates with the oil injection port 10. Thereby, the oil in the differential pressure chamber 8 whose pressure is increasing is discharged to the oil injection port 10 through the groove 24, and the oil is injected from the oil injection nozzle 50 toward the piston.

  As the oil in the differential pressure chamber 8 is discharged to the oil injection port 10, the hydraulic pressure in the differential pressure chamber 8 immediately decreases. Thereby, the damage of the related parts by the excessive raise of the hydraulic pressure in the differential pressure chamber 8 is prevented. Further, since the oil discharged to the oil injection port 10 is injected toward the piston or between the piston and the piston bore, the scuff resistance at an extremely low temperature is ensured. Furthermore, the piston valve 20 is pushed down again to the bottom side of the cylinder 4 due to a decrease in the hydraulic pressure in the differential pressure chamber 8, and stops at a position where the oil injection port 10 which is a balance position in the cold state is closed. As a result, the oil in the differential pressure chamber 8 is stopped from being discharged to the oil injection port 10 through the groove 24 of the piston valve 20, and the unnecessary oil is prevented from being injected at an extremely low temperature. The

  As described above, according to the oil jet 100 according to the present embodiment, the valve opening pressure of the piston valve 20 can be mechanically automatically adjusted according to the oil temperature. Further, due to the effect of the groove 24 formed in the piston valve 20, it is possible to inject an appropriate amount of oil to the piston while preventing an excessive increase in hydraulic pressure at extremely low temperatures. Further, since the groove 24 is formed so as to be inclined downward from the outer peripheral side of the piston valve 20 toward the axis line side, oil remains in the groove 24 even after the internal combustion engine is stopped, An effect of functioning as lubricating oil between the piston valve 24 and the cylinder 4 at the time of starting is also obtained.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the shape of the leak hole may be a long hole that leads from the top surface or side surface of the stopper to the outer surface of the body. Alternatively, long pores and slits that lead from the bottom surface or side surface of the cylinder to the outer surface of the body can be formed as leak holes.

  Further, an oil jet 100 ′ having a configuration schematically shown in FIG. 7 may be employed. In the oil jet 100 shown in FIG. 7, an oil discharge port 12 that opens on the side surface of the cylinder 4 is provided separately from the oil injection port 10. The position of the oil discharge port 12 on the side surface of the cylinder 4 is closer to the bottom of the cylinder 4 than the oil injection port 10. The size of the piston valve 20 is set such that both the oil injection port 10 and the oil discharge port 12 can be closed simultaneously. Formation of the groove 24 on the outer peripheral surface of the piston valve 20 so that the groove 24 is positioned below the oil discharge port 12 in a state where the piston valve 20 is in a predetermined position blocking both the oil injection port 10 and the oil discharge port 12. The position has been determined.

  According to the configuration of the oil jet 100 ′ shown in FIG. 7, when the oil pressure in the differential pressure chamber 8 increases and the piston valve 20 is pushed up, the differential pressure chamber 8 and the oil discharge port 12 communicate with each other via the groove 24. To do. As a result, the oil in the differential pressure chamber 8 is discharged from the oil discharge port 12 through the groove 24, so that damage to related parts due to an excessive increase in the hydraulic pressure in the differential pressure chamber 8 is prevented. The configuration of the oil jet 100 ′ shown in FIG. 7 can be used when there is no need to supply oil even at an extremely low temperature, that is, when the scuff resistance at an extremely low temperature is secured by other means. .

2 Body 4 Cylinder 6 Oil supply port 8 Differential pressure chamber 10 Oil injection port 14 Spring seat 16 First spring 18 Second spring 20 Piston valve 22 Orifice 24 Groove 26 Communication hole 30 Plug 32 Stopper 34 Oil discharge hole 40 Holder 42 Leak hole (Annular gap)
44 Oil discharge chamber 50 Oil injection nozzle 52 Oil injection passage 60 Cylinder block 62 Oil passage 100 Oil jet

Claims (5)

An oil supply port that opens to an oil passage in a cylinder block of an internal combustion engine, a cylinder that has one end communicating with the oil supply port and the other end that is closed, and an oil injection port that opens to the side of the cylinder A body having
A piston valve that is housed in the cylinder and forms a closed compartment in the cylinder, the orifice communicating the closed compartment to the oil supply port side; and the closed compartment formed on at least a part of an outer periphery; A piston valve comprising a communicating groove;
A first spring that biases the piston valve toward the oil injection port;
A second spring that urges the piston valve toward the closed compartment;
The body is formed with a leak hole for oil to leak out of the body from the closed compartment,
In the first spring and the second spring, the piston valve is located at a position where the oil injection port is closed when a pressure difference between the pressure in the oil passage and the pressure in the closed compartment is within a predetermined range. A spring length and a spring constant so that the groove and the oil injection port communicate with each other when a differential pressure between the pressure in the oil passage and the pressure in the closed compartment deviates from the lower limit of the predetermined range. An oil jet characterized by being adjusted.   2. The oil jet according to claim 1, wherein the groove is an annular groove formed on the entire outer periphery of the piston valve.   3. The oil jet according to claim 1, wherein the groove is formed to be inclined downward from the outer peripheral side of the piston valve toward the axis side. 4. A columnar stopper that is inserted into the closed compartment from the bottom of the cylinder and restricts the movement range of the piston valve;
The oil according to any one of claims 1 to 3, wherein the leak hole is a gap formed between a hole formed in the body for passing the stopper and a side surface of the stopper. jet.   The oil jet according to claim 4, wherein the gap is an annular gap surrounding the stopper.

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