JP2014070612A - Piston cooling jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston cooling jet hard to be clogged with foreign matters in a pressure adjust passage.SOLUTION: A piston cooling jet 1 includes: a housing 2; a nozzle 3 projecting from the housing 2 and capable of injecting oil O to a piston 91; a valve 4 capable of reciprocating inside the housing 2, and including a valve body 40 to which a load Fu is applied from a surface side by an oil pressure in an engine side oil passage 900 and a shaft 41 projecting from the valve body 40 to a rear side and having a foreign matter removing part 410 on an outer circumferential face; a partition wall 5 arranged in the rear side of the valve body 40 and having a partition wall side hole 50 into which the shaft 41 is inserted and in which the foreign matter removing part 410 is moved; a pressure chamber 21 defined inside the housing 2 between the valve body 40 and the partition wall 5; a valve side oil passage 400 through which a surface side of the valve body 40 communicates with the pressure chamber 21; and a pressure adjust passage B defined between an inner circumferential face of the partition wall side hole 50 and an outer circumferential face of the shaft 41.

Description

  The present invention relates to a piston cooling jet that cools a piston by injecting oil onto the back surface of the piston of the engine.

  The piston cooling jet is attached to a cylinder block of the engine. The piston cooling jet communicates with the main oil gallery of the cylinder block. The main oil gallery constitutes a part of the engine oil circulation circuit. A hydraulic valve mechanism is arranged in the piston cooling jet.

  When the oil pressure of the oil in the main oil gallery exceeds a predetermined threshold value, the hydraulic valve mechanism of the piston cooling jet opens. For this reason, the oil of the main oil gallery is injected to the back surface of the piston by the piston cooling jet. The piston is cooled by the injection.

  Here, when the piston is warm, it is preferable to cool the piston with a piston cooling jet. However, when the piston is cold, it is necessary to raise the temperature of the piston early. For this reason, if a piston is cooled using a piston cooling jet at the time of cold, the temperature rise of a piston will be inhibited. Moreover, the oil injected on the back surface of the piston falls on the crankshaft. Here, when cold, the oil temperature is low. For this reason, the viscosity of oil is high. Therefore, oil with high viscosity falls on the crankshaft, and the rotation resistance of the crankshaft (stirring resistance against oil) increases. For these reasons, it is preferable not to inject oil when cold. However, the conventional hydraulic valve mechanism of the piston cooling jet opens and closes according to the oil pressure of the main oil gallery, not the temperature of the engine. For this reason, a piston cooling jet will operate | move even at the time of cold.

  In view of this point, Patent Document 1 discloses a piston cooling jet that includes a hydraulic valve mechanism and an oil temperature valve mechanism. According to the piston cooling jet of the same document, the hydraulic valve mechanism switches the oil injection state in accordance with the oil pressure. The oil temperature valve mechanism switches the oil injection state in accordance with the oil temperature.

  One coil spring is used for the hydraulic valve mechanism. Two coil springs are used in the oil temperature valve mechanism. The two coil springs of the oil temperature valve mechanism are arranged in series along the oil passage direction via the closing member. Of the two coil springs, the upper (upstream) coil spring is a shape memory spring made of shape memory alloy. The urging force of the coil spring varies with temperature. Of the two coil springs, the lower (downstream) coil spring is a bias spring.

  When cold, the bias spring has a greater urging force than the shape memory spring. Therefore, the oil passage is closed. Therefore, oil injection can be stopped.

  On the other hand, when warm, the shape memory spring has a larger biasing force than the bias spring. For this reason, the oil passage is open. Accordingly, oil injection can be allowed.

JP 2011-12650 A

  However, according to the piston cooling jet described in this document, a total of three coil springs are required. For this reason, the structure of the piston cooling jet is complicated. In addition, the number of parts is large.

  Moreover, according to the piston cooling jet described in the document, one of the three coil springs needs to be made of a shape memory alloy. For this reason, the manufacturing cost of a piston cooling jet becomes high.

  In view of this point, the present inventor has developed a novel piston cooling jet. However, the piston cooling jet is not a prior art. The piston cooling jet includes a housing, a valve, a plug, a holder, and a coil spring.

  The holder includes a holder side hole. The holder is accommodated in the lower part of the housing. The plug seals the opening at the lower end of the housing. A shaft protrudes upward from the plug. The shaft is accommodated in the housing. The shaft is inserted through the holder side hole. A leak gap is defined between the inner peripheral surface of the holder side hole and the outer peripheral surface of the shaft.

  The valve is accommodated in a housing (portion above the shaft) so as to be able to reciprocate. The valve movably partitions the interior of the housing into an upper pressure receiving chamber and a lower pressure chamber. An orifice is disposed in the valve. The coil spring is accommodated in the pressure chamber. The coil spring urges the valve. The pressure receiving chamber communicates with the main oil gallery of the engine. The oil in the main oil gallery flows out to the outside through a path of pressure receiving chamber → orifice → pressure chamber → leak gap.

  The piston cooling jet has an orifice upstream of the pressure chamber and a leak gap downstream of the pressure chamber. For this reason, the internal pressure of a pressure chamber can be changed according to the oil temperature and oil pressure of oil. In addition, the valve can be reciprocated between the valve opening position and the valve closing position using the change in the internal pressure.

  Thus, according to the novel piston cooling jet, oil injection control according to the oil temperature and oil pressure can be executed using a single coil spring. For this reason, the structure of the piston cooling jet is simple. In addition, the number of parts is small. In addition, according to the new piston cooling jet, the coil spring does not have to be made of a shape memory alloy. For this reason, the manufacturing cost of a piston cooling jet becomes low.

  In the case of the new piston cooling jet, in order to control the internal pressure of the pressure chamber, an oil path (path from the main oil gallery to the outside via the pressure receiving chamber, the orifice, the pressure chamber, and the leak gap) is secured. There is a need. However, there are cases where foreign matters such as sludge, wear powder, dust, and processing powder during engine manufacture are mixed in the oil. If foreign matter gets stuck in the oil path, the oil will not flow smoothly. For this reason, it becomes difficult to control the internal pressure of the pressure chamber. In particular, the leak gap has a small opening width. For this reason, foreign substances are likely to be clogged in the leak gap.

  The piston cooling jet of the present invention has been completed in view of the above problems. An object of the present invention is to provide a piston cooling jet in which foreign substances are not easily clogged in a pressure adjusting passage.

  (1) In order to solve the above problems, a piston cooling jet according to the present invention is capable of reciprocating within a housing, a nozzle that protrudes outward from the housing and that can inject oil into the piston, and the inside of the housing. A valve body having a load applied by oil pressure in the engine side oil passage from the front side, a valve projecting from the valve body on the back side and having a foreign matter discharge portion on the outer peripheral surface, and disposed on the back side of the valve body. A partition wall having a partition side hole through which the shaft is inserted and the foreign substance discharge portion moves, a pressure chamber defined between the valve body and the partition wall in the housing, and a front side of the valve body And a valve-side oil passage communicating with the pressure chamber, and a pressure adjusting passage defined between the inner peripheral surface of the partition-side hole and the outer peripheral surface of the shaft. And features.

  The valve shaft of the piston cooling jet according to the present invention is inserted into the partition wall side hole. When the valve reciprocates inside the housing, the foreign matter discharging portion of the shaft moves radially inside the partition side hole. At this time, the foreign matter discharger can discharge foreign matter (for example, sludge, wear powder, dust, processing powder during engine manufacture, etc.) clogged in the pressure adjustment passage from the pressure adjustment passage. For this reason, the foreign substance is not easily clogged in the pressure adjusting passage. Therefore, the oil for adjusting the internal pressure of the pressure chamber can flow through the engine side oil passage → valve side oil passage → pressure chamber → pressure adjustment passage → external route (other passages may be interposed in the middle). it can. Therefore, the internal pressure of the pressure chamber can be reliably controlled.

  By the way, the oil circulates in the engine through an oil pan → pump → oil filter → cylinder block → piston cooling jet → oil pan again as an example. Immediately after the engine is manufactured, there may be a case where the machining powder at the time of engine manufacture remains in the cylinder block. For this reason, when the engine is driven immediately after the engine is manufactured, the machining powder flows into the piston cooling jet before passing through the oil filter. Therefore, foreign matter is likely to be clogged in the pressure adjusting passage. In this regard, according to the piston cooling jet of the present invention, foreign matter can be discharged from the pressure adjusting passage even when the engine is driven immediately after the manufacture of the engine.

  (2) Preferably, in the configuration of (1), the valve-side oil passage has an orifice, and the pressure adjusting passage has an opening width smaller than the orifice and a total opening area larger than the orifice. It is better to have a configuration with a leak gap. According to this configuration, the internal pressure of the pressure chamber can be easily adjusted according to the oil temperature and oil pressure of the oil.

  (3) Preferably, in the configuration of the above (1) or (2), the foreign matter discharge portion is an annular rib that protrudes radially outward and extends annularly on the outer peripheral surface of the shaft. Good. According to this configuration, the foreign material can be discharged from the pressure adjusting passage by moving the annular rib in the radial direction inside the partition wall side hole as the valve reciprocates.

  (3-1) Preferably, in the configuration of the above (3), the surface of the annular rib should have a tapered surface shape whose diameter decreases from the back side toward the front side. According to this configuration, the foreign matter easily moves from the front side (pressure chamber side) to the back side (external side). On the other hand, the foreign matter hardly moves from the back side (external side) to the front side (pressure chamber side). For this reason, it is easy to discharge foreign matter from the pressure chamber to the outside.

  (4) Preferably, in the configuration of the above (1) or (2), the foreign matter discharge portion is a spiral rib that protrudes radially outward and extends spirally on the outer peripheral surface of the shaft. Better. According to this configuration, the foreign substance can be discharged from the pressure adjusting passage by moving the spiral rib in the radial direction inside the partition wall side hole as the valve reciprocates.

  (4-1) Preferably, in the configuration of (4) above, the surface of the spiral rib is preferably configured to have a tapered surface shape whose diameter decreases from the back side to the front side. According to this configuration, the foreign matter easily moves from the front side (pressure chamber side) to the back side (external side). On the other hand, the foreign matter hardly moves from the back side (external side) to the front side (pressure chamber side). For this reason, it is easy to discharge foreign matter from the pressure chamber to the outside.

  (5) Preferably, in any one of the constitutions (1) to (4), the partition wall has a foreign substance collecting recess recessed on the surface exposed to the pressure chamber toward the partition wall side hole. It is better to have a configuration. According to this configuration, foreign matter in the pressure chamber can be collected in the foreign matter collecting recess. Further, the collected foreign matter can be discharged to the outside through the partition wall side hole by the foreign matter discharge portion. Thus, according to this configuration, foreign matter can be easily discharged not only from the pressure adjustment passage but also from the pressure chamber.

  (6) Preferably, in any one of the configurations (1) to (5), the valve-side oil passage may be configured to penetrate the valve body in the front-back direction. According to this configuration, the valve-side oil passage can be secured without processing the housing.

  According to the present invention, it is possible to provide a piston cooling jet that does not easily clog foreign substances in the pressure adjusting passage.

It is a layout view of the piston cooling jet of the first embodiment. It is a perspective view of the piston cooling jet. It is a disassembled perspective sectional view of the same piston cooling jet. It is an up-down direction sectional view of the valve closing state of the piston cooling jet. It is a vertical direction sectional view of the valve opening state of the piston cooling jet. It is an enlarged view in the frame VI of FIG. It is an enlarged view in the frame VII of FIG. It is an up-down direction expanded sectional view of the valve-opening state of the piston cooling jet of a second embodiment. It is an up-down direction expanded sectional view of the valve closing state of the piston cooling jet of a third embodiment. It is the circumferential direction developed view of the outer peripheral surface of the shaft of the valve | bulb of the piston cooling jet of 4th embodiment. (A) is an up-down direction expanded sectional view of the shaft of the valve | bulb of the piston cooling jet (the 1) of other embodiment. (B) is an up-down direction expanded sectional view of the shaft of the valve | bulb of the piston cooling jet (the 2) of other embodiment. (C) is an up-down direction expanded sectional view of the shaft of the valve | bulb of the piston cooling jet (the 3) of other embodiment. (D) is an up-down direction expanded sectional view of the shaft of the valve of the piston cooling jet (the 4) of other embodiments. It is sectional drawing of the up-down direction of the valve opening state of the piston cooling jet of other embodiment (the 5). It is sectional drawing of the up-down direction of the valve opening state of the piston cooling jet of other embodiment (the 6). It is sectional drawing of the up-down direction of the valve opening state of the piston cooling jet of other embodiment (the 7).

  Hereinafter, embodiments of the piston cooling jet of the present invention will be described.

<First embodiment>
[Piston cooling jet arrangement]
First, the arrangement of the piston cooling jet of this embodiment will be described. FIG. 1 shows a layout diagram of the piston cooling jet of the present embodiment. As shown in FIG. 1, the engine 9 includes a cylinder block 90, a piston 91, a connecting rod 92, and a crankshaft 93.

  The piston 91 is connected to the crankshaft 93 via a connecting rod 92. The piston 91 can reciprocate up and down in the cylinder block 90. A main oil gallery 900 is formed in the cylinder block 90. The main oil gallery 900 is included in the concept of the “engine side oil passage” of the present invention. The main oil gallery 900 constitutes a part of the oil circulation circuit of the engine 9. The piston cooling jet 1 is attached to the cylinder block 90.

  Note that the piston cooling jet 1 shown in FIG. 1 is in a valve open state. As shown by a dotted line in FIG. 1, the piston cooling jet 1 can inject the oil O in the main oil gallery 900 onto the lower surface of the piston 91 (the back surface, that is, the surface opposite to the combustion chamber).

[Configuration of piston cooling jet]
Next, the structure of the piston cooling jet of this embodiment is demonstrated. In the following drawings, the upper side corresponds to the “front side” of the present invention. The lower side corresponds to the “back side” of the present invention. In FIG. 2, the perspective view of the piston cooling jet of this embodiment is shown. FIG. 3 is an exploded perspective sectional view of the piston cooling jet. FIG. 4 shows a vertical sectional view of the piston cooling jet in a closed state. FIG. 5 shows a vertical cross-sectional view of the piston cooling jet in the valve open state.

  As shown in FIGS. 1 to 5, the piston cooling jet 1 includes a housing 2, a nozzle 3, a valve 4, a partition wall 5, a coil spring 70, a bracket 71, and a rib 73.

(Housing 2, bracket 71, rib 73)
The housing 2 is made of steel and has a cylindrical shape. As shown in FIG. 1, the housing 2 is fixed to the cylinder block 90 via a bracket 71 with bolts (not shown). As shown in FIGS. 4 and 5, the housing 2 includes a pressure receiving chamber 20, a pressure chamber 21, a housing-side nozzle communication hole 22, a first step portion 23, and a second step portion 24. .

  The pressure receiving chamber 20 and the pressure chamber 21 are partitioned inside the housing 2. The pressure receiving chamber 20 and the pressure chamber 21 are partitioned by a valve 4 described later. That is, the pressure receiving chamber 20 is disposed on the upper side of the valve 4. On the other hand, the pressure chamber 21 is disposed below the valve 4. The volumes of the pressure receiving chamber 20 and the pressure chamber 21 change according to the movement of the valve 4.

  The rib 73 is made of steel and has an annular shape. The rib 73 is disposed on the inner peripheral surface of the housing 2 (the inner peripheral surface of the pressure chamber 21). The rib 73 projects radially inward. When viewed from the upper side or the lower side, the rib 73 is disposed so as to overlap the outer peripheral edge of the valve body 40 described later. In addition, the rib 73 is disposed so as not to overlap with a coil spring 70 described later when viewed from the upper side or the lower side. The rib 73 determines the bottom dead center (valve opening position) of the valve 4 described later. That is, in the valve open state, the rib 73 supports the valve 4 from below.

  The housing-side nozzle communication hole 22 penetrates the side peripheral wall of the housing 2. The cross section of the housing side nozzle communication hole 22 has a perfect circle shape. The first step portion 23 is disposed near the upper end (one axial end) inside the housing 2. The first step portion 23 has a tapered surface shape whose diameter decreases from the lower side toward the upper side. The first step portion 23 determines the top dead center (valve closing position) of the valve 4 described later. The second step portion 24 is disposed near the lower end (the other end in the axial direction) inside the housing 2. The second step portion 24 has a stepped shape with a diameter decreasing from the lower side toward the upper side. The second step portion 24 determines the mounting position of the partition wall 5 to be described later.

(Nozzle 3, valve 4)
As shown in FIGS. 4 and 5, the nozzle 3 is made of steel and has a long-axis cylindrical shape. The nozzle 3 protrudes radially outward from the side peripheral wall of the housing 2. As shown in FIG. 1, the upper end (one axial end) of the nozzle 3 faces the direction of the piston 91. The lower end (the other end in the axial direction) of the nozzle 3 is connected to the housing side nozzle communication hole 22 of the housing 2.

  The valve 4 is made of steel and includes a valve main body 40 and a shaft 41. The valve body 40 includes a valve-side oil passage 400 and a valve-side spring seat 401. The valve-side oil passage 400 passes through the valve body 40 in the vertical direction (axial direction). The cross section of the valve-side oil passage 400 has a perfect circle shape. The valve-side oil passage 400 is arranged so as to be shifted from the radial center of the valve body 40. An orifice (throttle portion) A is disposed in the middle portion of the valve-side oil passage 400. The cross section of the orifice A has a perfect circle shape. The cross-sectional area of the valve-side oil passage 400 in the horizontal direction (axial direction) is locally reduced at the orifice A.

  The valve-side spring seat 401 is arranged on the entire lower periphery of the outer peripheral surface of the valve body 40. The valve-side spring seat 401 has a stepped shape that expands from the lower side toward the upper side.

  The shaft 41 projects from the lower surface of the valve main body 40 toward the lower side (the pressure chamber 21 side). The shaft 41 is disposed at the radial center of the valve body 40. The shaft 41 has a long cylindrical shape extending in the vertical direction. The cross section of the shaft 41 has a perfect circle shape. The shaft 41 is inserted inside the rib 73 in the radial direction. The shaft 41 is inserted into a partition wall side hole 50 described later.

  A plurality of annular ribs 410 are formed on the outer peripheral surface of the shaft 41. Each of the plurality of annular ribs 410 protrudes radially outward from the outer peripheral surface of the shaft 41. Each of the plurality of annular ribs 410 goes around the outer peripheral surface of the shaft 41. Each of the plurality of annular ribs 410 has a triangular cross section. Specifically, as shown in FIGS. 4 and 5, the vertical cross-sections of the plurality of annular ribs 410 each have a downward-facing right triangle shape.

  FIG. 6 shows an enlarged view in the frame VI of FIG. 4 (that is, the valve closed state). FIG. 7 shows an enlarged view in the frame VII of FIG. 5 (that is, the valve opened state). A part of the plurality of annular ribs 410 is disposed on the radially inner side of the partition wall side hole 50 described later in the valve-closed state shown in FIGS. 4 and 6. Further, another part of the plurality of annular ribs 410 is disposed on the radially inner side of the partition wall side hole 50 described later in the valve open state shown in FIGS. 5 and 7. That is, the plurality of annular ribs 410 are disposed in a predetermined axial section of the outer peripheral surface of the shaft 41 so as to continue to be disposed on the radially inner side of the partition wall side hole 50 from the closed state to the opened state.

(Partition wall 5, coil spring 70)
As shown in FIGS. 3 to 7, the partition wall 5 is made of steel and has an annular shape. The partition wall 5 is fixed to the opening at the lower end of the housing 2 so as to contact the second stepped portion 24 of the housing 2. The pressure chamber 21 is partitioned between the valve body 40 and the partition wall 5.

  The partition wall 5 includes a partition wall side hole 50 and a partition wall side spring seat 51. The partition side hole 50 penetrates the partition wall 5 in the vertical direction. The partition wall side hole 50 is disposed at the radial center of the partition wall 5. The cross section of the partition wall side hole 50 has a perfect circle shape. The inner diameter of the partition wall side hole 50 is constant over the entire length of the partition wall side hole 50 in the vertical direction.

  A shaft 41 is inserted inside the partition side hole 50 in the radial direction. The partition side hole 50 and the shaft 41 are arranged coaxially. The leak gap B is defined between the outer peripheral surface of the shaft 41 (that is, the plurality of annular ribs 410) and the inner peripheral surface of the partition wall side hole 50. The leak gap B has an annular shape. The radial width of the leak gap B (the width between the inner peripheral surface of the partition wall side hole 50 and the radial outer end of the annular rib 410, that is, the opening width) is larger than the diameter (opening width) of the orifice A. It is set small. Further, the passage cross-sectional area (total opening area) in the horizontal direction (straight axis direction) of the leak gap B is set larger than the passage cross-sectional area (total opening area) in the horizontal direction (straight axis direction) of the orifice A. Yes.

  The partition-side spring seat 51 is disposed on the upper surface of the partition 5. The partition side spring seat 51 is disposed on the radially outer side of the partition side hole 50. The partition-side spring seat 51 has an annular rib shape.

  The coil spring 70 is made of steel, and is interposed between the valve side spring seat 401 and the partition wall side spring seat 51. As shown in FIGS. 4 to 7, the coil spring 70 biases the valve 4 upward (in the direction of switching from the valve open state to the valve close state).

[Load applied to the valve of the piston cooling jet]
Next, the load applied to the valve of the piston cooling jet of this embodiment will be briefly described. As shown in FIGS. 4 and 5, a load Fu due to the hydraulic pressure of the oil O of the main oil gallery 900 is applied to the upper surface of the valve 4 from the upper side. On the other hand, a load Fd1 due to the urging force of the coil spring 70 is applied to the lower surface of the valve 4 from below. In addition, a load Fd2 due to the internal pressure of the pressure chamber 21 (oil pressure of oil O) is applied to the lower surface of the valve 4 from below.

  Thus, the load Fu is applied to the valve 4 from the upper side and the loads Fd1 and Fd2 are applied from the lower side. The valve 4 reciprocates in the vertical direction according to the magnitude relationship between these loads. The valve 4 is also subjected to a load due to its own weight, buoyancy, etc. depending on the mounting direction of the piston cooling jet 1, but is omitted here for convenience of explanation.

[Piston cooling jet movement]
Next, the movement of the piston cooling jet of this embodiment will be described. As described above, the load Fu is applied to the valve 4 from the upper side and the loads Fd1 and Fd2 are applied from the lower side. The valve 4 reciprocates in the vertical direction according to the magnitude relationship between these loads. That is, the piston cooling jet 1 is switched between a valve closing state shown in FIG. 4 and a valve opening state shown in FIG.

  It is the internal pressure of the pressure chamber 21 that determines the load Fd2. The internal pressure in the pressure chamber 21 varies depending on the relationship between the flow rate Q1 of the oil O flowing into the pressure chamber 21 and the flow rate Q2 of the oil O flowing out of the pressure chamber 21.

That is, the oil O flows into the pressure chamber 21 via the orifice A. Therefore, the density of the oil O is ρ, the hydraulic pressure in the pressure receiving chamber 20 (that is, in the main oil gallery 900 shown in FIG. 1) is Pa, the hydraulic pressure in the pressure chamber 21 is Pb, the flow coefficient is K1, and the flow path of the orifice A Assuming that the cross-sectional area is S, the flow rate of the oil O passing through the orifice A, that is, the flow rate Q1 of the oil O flowing into the pressure chamber 21 is derived from the following equation (1) by Bernoulli's theorem.

  From equation (1), it can be seen that the flow rate Q1 of the oil O flowing into the pressure chamber 21 is affected by the density ρ of the oil O. Here, the density ρ of the oil O does not change much even if the oil temperature of the oil O changes. For this reason, from the time of cold (after the engine 9 is started and the engine 9 has not been warmed up and the piston 91 is at a low temperature) from the time of warm (after the engine 9 has been warmed up, the piston 91 is at a high temperature). The density ρ of the oil O does not change so much. Therefore, the flow rate Q1 of the oil O flowing into the pressure chamber 21 does not change so much from the cold time to the warm time.

On the other hand, the oil O flows out from the pressure chamber 21 via the leak gap B. Therefore, if the viscosity of the oil O is η, the coefficient is K2, and the atmospheric pressure is Pc, the flow rate of the oil O passing through the leak gap B, that is, the flow rate of the oil O flowing out from the pressure chamber 21 according to Hagen-Poiseuille's law. Q2 is derived from the following equation (2).

  From equation (2), it can be seen that the flow rate Q2 of the oil O flowing out of the pressure chamber 21 is affected by the viscosity η of the oil O. Here, the viscosity η of the oil O changes greatly as the oil temperature of the oil O changes. For this reason, the viscosity η of the oil O changes greatly when it reaches from the cold to the warm. Therefore, the flow rate Q2 of the oil O flowing out from the pressure chamber 21 changes greatly when it reaches from the cold time to the warm time. Specifically, the viscosity η decreases as the oil temperature increases. For this reason, the flow rate Q2 increases from the equation (2).

  Thus, the change of the flow rate Q2 with respect to the change of the oil temperature is large with respect to the change of the flow rate Q1 with respect to the change of the oil temperature. For this reason, the higher the oil temperature, the easier the oil O leaks from the leak gap B. Therefore, the higher the oil temperature, the smaller the internal pressure in the pressure chamber 21. Therefore, the higher the oil temperature, the smaller the load Fd2.

  When the oil temperature is low, the load Fd2 is large. For this reason, when the piston cooling jet 1 is switched from the valve closing state shown in FIG. 4 to the valve opening state shown in FIG. 5, a large load Fu is required. That is, the valve opening pressure increases.

  On the other hand, when the oil temperature is high, the load Fd2 is small. For this reason, when switching the piston cooling jet 1 from the valve-closed state shown in FIG. 4 to the valve-opened state shown in FIG. 5, a small load Fu is sufficient. That is, the valve opening pressure is reduced.

  Thus, according to the piston cooling jet 1 of this embodiment, the valve opening pressure is automatically adjusted according to the oil temperature.

[Function and effect]
Next, the effect of the piston cooling jet of this embodiment is demonstrated. As shown in FIGS. 4 to 7, the piston cooling jet 1 of the present embodiment can perform oil injection control according to the oil temperature and the hydraulic pressure using the orifice A, the leak gap B, and the coil spring 70. . For this reason, the structure of the piston cooling jet 1 is simple. In addition, the number of parts is small.

  As a conventional technique for operating the piston cooling jet according to the oil temperature, a spring made of a shape memory alloy is used. That is, a spring whose spring constant changes according to the oil temperature is used. In this regard, according to the piston cooling jet 1 of the present embodiment, a spring made of a shape memory alloy is not necessary. For this reason, the manufacturing cost of the piston cooling jet 1 becomes low.

  As shown in FIGS. 5 and 7, according to the piston cooling jet 1 of the present embodiment, the valve 4 contacts the rib 73 in the valve open state. For this reason, the valve opening position of the valve 4 can be regulated. Further, the maximum compression amount of the coil spring 70 can be regulated. Therefore, the coil spring 70 is difficult to sag.

  As shown in FIGS. 4 to 7, the leak clearance B of the piston cooling jet 1 according to the present embodiment includes an outer peripheral surface of the shaft 41 (that is, a plurality of annular ribs 410) and an inner peripheral surface of the partition wall side hole 50. , Is divided between. That is, one of the members forming the leak gap B is integrated with the valve 4. For this reason, compared with the case where the shaft 41 and the valve 4 are separate bodies, the number of parts can be reduced. Further, the length of the housing 2 and the piston cooling jet 1 in the vertical direction can be shortened. That is, the piston cooling jet 1 can be reduced in size. Therefore, as shown in FIG. 1, the piston cooling jet 1 is less likely to interfere with adjacent members such as the crankshaft 93.

  As shown in FIGS. 4 to 7, as the valve 4 moves, the shaft 41 moves relative to the partition wall 5 in the vertical direction. For this reason, for example, even when the foreign matter P is clogged in the leak gap B in the valve closing state shown in FIG. 6, when the shaft 41 is lowered when the valve 41 is switched to the valve opening state shown in FIG. Thus, the foreign matter P can be discharged from the leak gap B to the outside by the plurality of annular ribs 410. Further, even when the foreign matter P cannot be discharged by one switching (the valve closed state → the valve opened state), as shown in FIG. It moves in steps from the gap 410c between 410 to the gap 410c between any pair of lower annular ribs 410. For this reason, the foreign matter P can be finally discharged | emitted from the leak clearance B outside by performing switching several times.

  Similarly, even when the foreign matter P is clogged in the leak gap B in the valve open state shown in FIG. 7, as the shaft 41 rises when switching to the valve closed state shown in FIG. 6, The plurality of annular ribs 410 can discharge the foreign matter P from the leak gap B to the pressure chamber 21.

  Therefore, according to the piston cooling jet 1 of the present embodiment, the foreign matter P is hardly clogged in the leak gap B. Therefore, the internal pressure of the pressure chamber 21 can be reliably controlled.

  Moreover, as shown in FIGS. 4-7, the up-down direction cross section of the some annular rib 410 is exhibiting the downward right-angled triangle shape, respectively. That is, as shown in FIG. 6, the upper surface 410a of the annular rib 410 has a tapered surface shape whose diameter decreases from the lower side toward the upper side. On the other hand, the lower surface 410b of the annular rib 410 has a horizontal plane extending in the front-rear and left-right directions (the radial direction of the shaft 41). A gap 410c between a pair of annular ribs 410 adjacent in the vertical direction is defined between a lower surface 410b of the upper annular rib 410 and an upper surface 410a of the lower annular rib 410. Since the lower surface 410b extends in a horizontal plane and the upper surface 410a extends in a tapered surface, the gap 410c is open radially outward and downward. For this reason, it is easier to discharge the foreign matter P from the leak gap B to the outside when the shaft 41 is lowered than when the shaft 41 is raised. Accordingly, the foreign matter P is not easily accumulated in the pressure chamber 21.

  Further, immediately after the manufacture of the engine 9, there may be a case where the machining powder at the time of manufacture remains in the cylinder block 90. For this reason, when the engine 9 is driven immediately after manufacture, the machining powder flows into the piston cooling jet 1 before passing through the oil filter. Therefore, the foreign matter P is easily clogged in the leak gap B. In this regard, according to the piston cooling jet 1 of the present embodiment, foreign matter can be discharged from the leak gap B even when the engine 9 is driven immediately after manufacture.

  As shown in FIG. 3, the valve-side oil passage 400 of the piston cooling jet 1 of the present embodiment is formed in the valve body 40. For this reason, the valve-side oil passage 400 can be secured without processing the housing 2.

<Second embodiment>
The difference between the piston cooling jet of this embodiment and the piston cooling jet of the first embodiment is that only one annular rib is arranged on the shaft. Here, only differences will be described.

  FIG. 8 is an enlarged cross-sectional view in the vertical direction of the piston cooling jet of the present embodiment in the valve open state. In addition, about the site | part corresponding to FIG. 7, it shows with the same code | symbol. As shown in FIG. 8, a single annular rib 410 is disposed on the outer peripheral surface of the shaft 41. The cross section in the vertical direction of the annular rib 410 has an equilateral triangle shape. In the valve open state shown in FIG. 8, the annular rib 410 is disposed below the leak gap B. The section L is a section arranged on the radially inner side of the partition wall side hole 50 in the valve closed state on the outer peripheral surface of the shaft 41. In the closed state, the annular rib 410 is disposed above the leak gap B.

  As described above, the annular rib 410 is disposed below the leak gap B in the valve-open state and above the leak gap B in the valve-closed state. When switching from the open state to the closed state or from the closed state to the open state, the annular rib 410 passes through the leak gap B in the vertical direction. When passing, the annular rib 410 can discharge foreign matter from the leak gap B.

  The piston cooling jet according to the present embodiment and the piston cooling jet according to the first embodiment have the same functions and effects with respect to the parts having the same configuration. As in the piston cooling jet of this embodiment, only one annular rib 410 may be arranged.

<Third embodiment>
The difference between the piston cooling jet of the present embodiment and the piston cooling jet of the first embodiment is that a foreign substance collecting recess is disposed in the partition wall. Here, only differences will be described.

  FIG. 9 shows an enlarged vertical sectional view of the piston cooling jet according to the present embodiment in a closed state. In addition, about the site | part corresponding to FIG. 6, it shows with the same code | symbol. As shown in FIG. 9, a foreign matter collecting recess 510 is provided on the upper surface of the partition wall side spring seat 51 of the partition wall 5. The foreign matter collecting recess 510 has a tapered surface shape whose diameter decreases from the upper side to the lower side. The partition hole 50 is disposed at the center in the radial direction of the foreign material collecting recess 510. That is, the foreign material collecting recess 510 is recessed toward the opening at the upper end of the partition wall side hole 50.

  The piston cooling jet according to the present embodiment and the piston cooling jet according to the first embodiment have the same functions and effects with respect to the parts having the same configuration. According to the piston cooling jet of the present embodiment, the foreign matter P inside the pressure chamber 21 tends to gather in the foreign matter collecting recess 510 due to the flow of oil O and its own weight. The collected foreign matter P is discharged to the outside through the partition wall side holes 50 by the plurality of annular ribs 410 when the valve closing state is switched to the valve opening state. Thus, according to the piston cooling jet of the present embodiment, the foreign matter P can be easily discharged not only from the leak gap B but also from the pressure chamber 21 to the outside.

<Fourth embodiment>
The difference between the piston cooling jet of the present embodiment and the piston cooling jet of the first embodiment is that a single helical rib is arranged on the shaft. Here, only differences will be described.

  FIG. 10 shows a circumferential development of the outer peripheral surface of the shaft of the valve of the piston cooling jet of the present embodiment. In addition, about the site | part corresponding to FIG. 3, it shows with the same code | symbol. As shown by hatching in FIG. 10, spiral ribs 411 are formed on the outer peripheral surface of the shaft 41. The spiral rib 411 protrudes radially outward from the outer peripheral surface of the shaft 41. The plurality of spiral ribs 411 extend in a spiral manner on the outer peripheral surface of the shaft 41 over three circumferences.

  The piston cooling jet according to the present embodiment and the piston cooling jet according to the first embodiment have the same functions and effects with respect to the parts having the same configuration. Even if the spiral rib 411 is disposed as in the piston cooling jet of the present embodiment, foreign matter can be discharged from the leak gap.

<Others>
The embodiment of the piston cooling jet of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  The shapes of the cross sections in the vertical direction of the annular rib 410 and the spiral rib 411 are not particularly limited. FIG. 11A is an enlarged cross-sectional view in the vertical direction of the valve shaft of the piston cooling jet (No. 1) of another embodiment. FIG. 11B is an enlarged vertical sectional view of the shaft of the valve of the piston cooling jet (part 2) of the other embodiment. FIG. 11C is an enlarged vertical sectional view of the valve shaft of the piston cooling jet (No. 3) of another embodiment. FIG. 11D shows an enlarged vertical sectional view of a shaft of a valve of a piston cooling jet (No. 4) according to another embodiment. In addition, about the site | part corresponding to FIG. 6, it shows with the same code | symbol.

  As shown in FIG. 11A, the vertical cross section of the annular rib 410 may be an isosceles triangle. As shown in FIG. 11B, the vertical cross section of the annular rib 410 may be rectangular. As shown in FIG. 11 (c), the vertical cross section of the annular rib 410 may be a downward hook shape. As shown in FIG. 11 (d), the vertical cross section of the annular rib 410 may be semicircular. Moreover, the up-down direction cross section of the cyclic | annular rib 410 shown in FIG.11 (c) may be an upward hook shape. This makes it easier to discharge foreign matter in the leak gap to the pressure chamber. For the same reason, the vertical cross section of the annular rib 410 shown in FIG. Moreover, the cross-sectional shape like FIG. 11 (a)-FIG.11 (d) may be sufficient as the up-down direction cross section of the helical rib 411. FIG. Further, the cross-sectional shapes of the annular rib 410 and the spiral rib 411 may be polygonal shapes (triangle, quadrangle, pentagon, hexagon, etc.). A curved chamfered portion may be arranged at the vertices in the radial direction of the annular rib 410 and the spiral rib 411.

  The location of the valve-side oil passage 400 is not particularly limited. It is only necessary that the pressure receiving chamber 20 (upper side of the valve body 40) and the pressure chamber 21 (lower side of the valve body 40) can communicate with each other. FIG. 12 shows a vertical cross-sectional view of the valve opening state of the piston cooling jet of the other embodiment (No. 5). FIG. 13 is a vertical cross-sectional view of the piston cooling jet of the other embodiment (No. 6) in the valve open state. FIG. 14 is a vertical sectional view of the piston cooling jet of the other embodiment (part 7) in the valve open state. 12 to 14, parts corresponding to those in FIG. 5 are denoted by the same reference numerals.

  As shown in FIG. 12, a hole-shaped valve-side oil passage 400 may be formed inside the side peripheral wall of the housing 2. This eliminates the need to process the inside of the valve body 40, the outer peripheral surface of the valve main body 40, and the inner peripheral surface of the housing 2. For this reason, the sliding resistance between the outer peripheral surface of the valve body 40 and the inner peripheral surface of the housing 2 is reduced.

  As shown in FIG. 13, a groove-like valve-side oil passage 400 may be provided in the inner peripheral surface of the housing 2. In this way, there is no need to process the inside of the valve body 40, the outer peripheral surface of the valve body 40, and the inside of the housing 2.

  As shown in FIG. 14, a groove-shaped valve-side oil passage 400 may be provided in the outer peripheral surface of the valve body 40. In this case, it is not necessary to process the inside of the valve body 40, the inner peripheral surface of the housing 2, and the inside of the housing 2.

  The rib 73 shown in FIGS. 13 and 14 has a partial arc shape. A total of three ribs 73 are arranged at 120 ° intervals in the circumferential direction so as not to interfere with the valve-side oil passage 400.

  As shown in FIG. 3, in the above embodiment, the partition wall 5 is brought into contact with the second stepped portion 24 of the housing 2 and the lower end of the housing 2 is crimped (reduced in diameter), whereby the partition wall 5 is attached to the housing 2. Fixed. However, the method for fixing the partition wall 5 to the housing 2 is not particularly limited. For example, the partition wall 5 may be fixed to the housing 2 by bolts, screws, clips, engaging claws, or the like. Further, the housing 2 and the partition wall 5 may be integrated.

  4 and 5, the pressure receiving chamber 20, the pressure chamber 21, the valve-side oil passage 400, the housing-side nozzle communication hole 22, the internal space of the nozzle 3, and the cross-sectional shape of the orifice A in the direction perpendicular to the passage direction. Is not particularly limited. For example, a perfect circle shape, an ellipse shape, a polygonal shape, etc. may be sufficient.

  As shown in FIGS. 6 and 7, the cross-sectional shape in the direction orthogonal to the passage direction of the leak gap B is not particularly limited. For example, a circular shape such as a perfect circular shape, an elliptical shape, or a polygonal shape may be used. When the cross-sectional shape of the leak gap B is elliptical, the cross-sectional shape of the shaft 41 (annular rib 410, spiral rib 411) and partition wall side hole 50 may be elliptical. In addition, when the cross-sectional shape of the leak gap B is rectangular, the cross-sectional shapes of the shaft 41 (annular rib 410, spiral rib 411) and partition wall side hole 50 may be rectangular.

  Further, when the opening shapes of the orifice A and the leak gap B are long (for example, slit shape, annular shape, etc.), the “opening width” of the present invention refers to the width in the short direction of the orifice A and the leak gap B. .

  In addition, when the opening shape of the orifice A is a perfect circle, an ellipse, or a polygon, the “opening width” of the present invention refers to a linear length that passes through the center of gravity of the figure of the orifice A. For example, when the orifice A has a perfect circle shape, the “opening width” of the present invention refers to the length of the diameter.

  As shown in FIGS. 6 and 7, in the above embodiment, the orifice A is disposed in the valve-side oil passage 400. However, the orifice A may not be disposed in the valve side oil passage 400.

  As shown in FIG. 10, in the fourth embodiment, a single spiral rib 411 is arranged. However, a plurality of spiral ribs 411 may be arranged. Further, the number of turns of the spiral rib 411 on the outer peripheral surface of the shaft 41 is not particularly limited. Preferably, it is better to make one round (360 °) or more. The reason is that the spiral rib 411 is disposed over the entire circumference of the shaft 41. Further, an annular rib 410 and a spiral rib 411 may be arranged on the inner peripheral surface of the partition wall side hole 50.

  The shape of the rib 73 is not particularly limited. As shown in FIGS. 6 and 7, it may be an endless ring. Moreover, as shown in FIG. 13, FIG. 14, a partial circular arc shape may be sufficient. Further, it may be an end ring (C shape). Further, instead of the rib 73, a protrusion protruding inward in the radial direction may be arranged. There are no particular limitations on the number of end-like annular ribs 73 and protrusions.

1: Piston cooling jet.
2: housing, 20: pressure receiving chamber, 21: pressure chamber, 22: housing side nozzle communication hole, 23: first stepped portion, 24: second stepped portion.
3: Nozzle.
4: valve, 40: valve body, 400: valve side oil passage, 401: valve side spring seat, 41: shaft, 410: annular rib, 410a: upper surface, 410b: lower surface, 410c: gap, 411: spiral rib.
5: partition wall, 50: partition wall side hole, 51: partition wall side spring seat, 510: foreign matter collecting recess.
70: Coil spring, 71: Bracket, 73: Rib.
9: Engine, 90: Cylinder block, 900: Main oil gallery (engine side oil passage), 91: Piston, 92: Connecting rod, 93: Crankshaft.
A: Orifice, B: Leak gap, Fd1: Load, Fd2: Load, Fu: Load, O: Oil, P: Foreign matter.

Claims (6)

A housing;
A nozzle protruding outward from the housing and capable of injecting oil into the piston;
A valve body capable of reciprocating in the housing, to which a load due to oil pressure in the engine side oil passage is applied from the front side, and a shaft projecting from the valve body on the back side and having a foreign matter discharge portion on the outer peripheral surface. A valve,
A partition wall disposed on the back side of the valve body, the partition wall having a partition wall side hole through which the shaft is inserted and the foreign matter discharge part moves;
A pressure chamber defined between the valve body and the partition wall in the housing;
A valve side oil passage communicating the front side of the valve body and the pressure chamber;
A pressure adjusting passage defined between the inner peripheral surface of the partition wall side hole and the outer peripheral surface of the shaft;
Piston cooling jet with The valve side oil passage has an orifice,
2. The piston cooling jet according to claim 1, wherein the pressure adjusting passage is a leak gap having an opening width smaller than the orifice and a total opening area larger than the orifice.   3. The piston cooling jet according to claim 1, wherein the foreign matter discharge portion is an annular rib that protrudes radially outward and extends annularly on an outer peripheral surface of the shaft.   3. The piston cooling jet according to claim 1, wherein the foreign matter discharge portion is a spiral rib that protrudes radially outward and extends spirally on the outer peripheral surface of the shaft.   5. The piston cooling jet according to claim 1, wherein the partition wall has a foreign matter collecting recess recessed toward the partition wall side hole on a surface exposed to the pressure chamber.   The piston cooling jet according to any one of claims 1 to 5, wherein the valve-side oil passage passes through the valve body in a front-back direction.

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