JP2012188996A - Relief mechanism for lubricant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relief mechanism for a lubricant that can perform operation suitable for viscosity for the lubricant.SOLUTION: The oil relief mechanism includes: a first opening provided in a proximal end of a valve body and communicating with an ejection side of an oil pump; a second opening provided in an end of the valve body and communicating with an oil sink of the internal combustion engine; a relief hole provided between the proximal end and the distal end of the valve body and communicating with a suction side of the oil pump; a communication passage for connecting the first opening to the relief hole when a spool is located at the proximal end in a sliding direction and for interrupting the first opening to the relief hole when the spool is located at the distal end in the sliding direction; a biasing member for biasing the spool toward the proximal end; and an orifice provided between the second opening and the oil sink.

Description

  The present invention relates to a relief mechanism for returning a part of lubricating oil discharged from an oil pump provided in an internal combustion engine to the upstream side from the oil pump.

  A relief mechanism is known that reduces a back pressure acting on an oil pump by returning a part of lubricating oil discharged from an oil pump provided in an internal combustion engine to the upstream side of the oil pump. As such a relief mechanism, there are a return passage that connects an oil passage downstream from the oil pump and an oil passage upstream from the oil pump, a valve mechanism that opens and closes the return passage in response to the temperature of the lubricating oil, Have been proposed (see, for example, Patent Document 1).

JP 2001-263026 A JP 2008-163776 A Japanese Patent Application Laid-Open No. 06-159028

  By the way, the correlation between the viscosity and the temperature of the lubricating oil varies depending on the type (properties) of the lubricating oil. Therefore, according to the conventional technology, the return passage is blocked before the viscosity of the lubricating oil drops to the assumed value, or the return passage is not cut off even after the viscosity of the lubricating oil falls below the assumed value. Things can happen.

  If the return passage is interrupted before the viscosity of the lubricating oil decreases to the expected value, the load on the oil pump increases, and the output loss of the internal combustion engine accompanying the drive of the oil pump may increase. On the other hand, if the return passage is not blocked even after the viscosity of the lubricating oil falls below the expected value, there is a possibility that an oil film of sufficient thickness will not be formed on the lubricated part of the internal combustion engine, or equipment that operates using hydraulic pressure (For example, a hydraulic variable valve mechanism or the like) may not operate normally.

  The present invention has been made in view of various circumstances as described above, and its purpose is to return a part of lubricating oil discharged from an oil pump provided in the internal combustion engine to the upstream side from the oil pump. Thus, in the relief mechanism for reducing the back pressure acting on the oil pump, an operation suitable for the viscosity of the lubricating oil is performed.

The present invention has focused on the point of utilizing the viscosity of the lubricating oil in order to solve the above-described problems. That is, the present invention is a relief mechanism provided in a path through which lubricating oil of an internal combustion engine circulates,
A valve body in which an accommodation hole for slidably accommodating the spool is formed;
A first opening provided at a proximal end of the valve body in a sliding direction of the spool and communicating an oil passage from an oil pump to the internal combustion engine and the accommodation hole;
A second opening provided at the tip of the valve body in the sliding direction of the spool and communicating the oil reservoir provided in the internal combustion engine and the accommodation hole;
A relief hole provided on a wall surface between the proximal end and the distal end of the valve body, and communicating the oil passage upstream of the oil pump and the accommodation hole;
When the spool is located at the proximal end in the sliding direction, the first opening communicates with the relief hole, and when the spool is located at the distal end in the sliding direction, the first opening is provided. A communication path for blocking the opening and the relief hole;
A biasing member that biases the spool from the distal end side to the proximal end side in the sliding direction;
An orifice provided between the second opening and the oil reservoir;
I was prepared to.

  According to such an invention, when the operation of the internal combustion engine is stopped (when the oil pump is stopped), the spool receives the urging force of the urging member and contacts the base end of the valve body (the base end of the receiving hole). It will be in contact. In that case, the first opening and the relief hole are electrically connected via the communication path provided in the spool. Further, in the gap (hereinafter referred to as “reservoir chamber”) between the front end of the spool and the front end of the valve body (accommodating hole), the lubricating oil that has flowed from the oil reservoir through the orifice is stored.

  When the internal combustion engine is started (the oil pump is activated) in the state as described above, the lubricating oil discharged from the oil pump is supplied to the internal combustion engine and a part of the lubricating oil discharged from the oil pump Flows to the first opening. At this time, if the temperature of the lubricating oil is low, the viscosity of the lubricating oil increases. For this reason, the flow resistance of lubricating oil from the oil pump toward the internal combustion engine increases, and the back pressure acting on the oil pump may increase. However, since a part of the lubricating oil discharged from the oil pump flows from the first opening to the relief hole through the communication path, it is possible to avoid a situation in which the back pressure acting on the oil pump becomes excessively high. .

  A part of the lubricating oil supplied from the oil pump to the first opening flows into the relief hole through the communication path, but the remaining lubricating oil presses the spool from the proximal end side to the distal end side of the accommodation hole. It functions as a hydraulic fluid that works. When the pressure of the hydraulic oil becomes larger than the urging force of the urging member, the spool is displaced from the proximal end of the accommodation hole to the distal end side. The displacement speed of the spool at that time varies depending on the flow rate of the lubricating oil discharged from the storage chamber through the orifice to the oil reservoir (the flow rate of the lubricating oil passing through the orifice per unit time). In other words, the displacement speed of the spool varies depending on the flow resistance when the lubricating oil passes through the orifice.

  The magnitude of the flow resistance when the lubricating oil passes through the orifice varies depending on the viscosity of the lubricating oil. For example, when the viscosity of the lubricating oil is high, the flow resistance becomes larger than when the viscosity is low (the amount of lubricating oil that passes through the orifice per unit time decreases). For this reason, the displacement speed of the spool when the viscosity of the lubricating oil is high is slower than when the viscosity of the lubricating oil is low. When the displacement speed of the spool is low, the conduction time between the communication path and the relief hole (the conduction time between the first opening and the relief hole) is longer than when the spool is fast. Therefore, it is possible to avoid a situation where the relief hole is blocked before the viscosity of the lubricating oil is sufficiently lowered.

  On the other hand, when the viscosity of the lubricating oil is low, the flow resistance when the lubricating oil passes through the orifice is smaller than when the viscosity is high (the amount of lubricating oil that passes through the orifice per unit time increases). For this reason, the displacement speed of the spool when the viscosity of the lubricating oil is low is faster than when the viscosity of the lubricating oil is high. When the moving speed of the spool is fast, the conduction time between the first opening and the relief hole is shorter than when it is slow. That is, when the viscosity of the lubricating oil is low, the relief holes are blocked earlier than when the viscosity is high. Therefore, it is possible to avoid a situation in which the relief hole is not blocked even after the viscosity of the lubricating oil is sufficiently lowered.

  As described above, the lubricating oil relief mechanism of the present invention can operate in accordance with the viscosity of the lubricating oil, not the temperature of the lubricating oil. As a result, the output loss of the internal combustion engine due to the drive of the oil pump becomes large, or the lubricating oil supplied to the internal combustion engine is insufficient (for example, a sufficiently thick oil film is not formed on the lubricated part). It is possible to avoid a situation in which a device that operates using hydraulic pressure does not operate normally.

  The orifice in the present invention may be a variable orifice having a larger passage cross-sectional area when the temperature of the lubricating oil is high than when it is low. According to such a configuration, when the temperature of the lubricating oil is low and the viscosity of the lubricating oil is high, the conduction time between the first opening and the relief hole can be reliably increased, and the temperature of the lubricating oil can be increased. When the viscosity of the lubricating oil is high and the viscosity of the lubricating oil is low, the conduction time between the first opening and the relief hole can be reliably shortened. As a result, it is possible to more reliably avoid a situation where the output loss of the internal combustion engine due to the drive of the oil pump becomes large, a situation where the lubricating oil supplied to the internal combustion engine is insufficient, and the like.

  The biasing member in the present invention may be a coil spring disposed in a storage chamber between the tip of the spool and the tip of the valve body (accommodating hole). At that time, the base end of the coil spring may be fitted into the outer periphery of the spool. That is, the base end of the coil spring may be inserted into the gap between the outer wall of the spool and the inner wall of the accommodation hole. In that case, the sealing performance between the outer wall of the spool and the inner wall of the accommodation hole can be enhanced.

  According to the present invention, in the relief mechanism for reducing the back pressure acting on the oil pump by returning a part of the lubricating oil discharged from the oil pump provided in the internal combustion engine to the upstream side from the oil pump, An operation suitable for the viscosity of the oil can be performed.

It is a figure which shows the structure of the relief mechanism of the lubricating oil in a 1st Example. It is a figure which shows the relative relationship between the internal diameter of a 1st opening part, and the internal diameter of a communicating path. It is a figure which shows the state of the relief mechanism when a spool begins to displace from the base end to the front end side. It is a figure which shows the state of the relief mechanism when a spool reaches | attains the front-end | tip. It is a figure which shows the structure of the relief mechanism of the lubricating oil in 2nd Example.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

<Example 1>
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a view showing an embodiment of a lubricating oil relief mechanism according to the present invention. FIG. 1 shows an aspect of the relief mechanism when the internal combustion engine is in a stopped state (oil pump is stopped).

In FIG. 1, the relief mechanism includes a cylindrical valve body 1. In a cylindrical space (accommodating hole) 2 in the valve body 1, a cylindrical spool 3 having an outer diameter substantially the same as the inner diameter of the accommodating hole 2 is slidably accommodated. A first opening 4 that penetrates the wall surface of the valve body 1 is formed at a part of the base end (lower end in FIG. 1) of the valve body 1.

  The first opening 4 communicates with the oil passage 5. The oil passage 5 is a passage through which the oil pump 6 communicates with the main gallery of the internal combustion engine. The oil pump 6 is a pump that pumps up lubricating oil stored in the oil pan 7 and discharges it to the oil passage 5. The oil pump 6 is, for example, a trochoid pump that is driven using the power of the internal combustion engine.

  A second opening 8 that penetrates the valve body 1 is formed at a part of the tip of the valve body 1 (upper end in FIG. 1). The second opening 8 communicates with the oil reservoir 10 of the internal combustion engine via the orifice 9. The oil reservoir 10 is, for example, a space that is formed inside a cylinder block of an internal combustion engine and in which lubricating oil that has circulated through the cylinder head drops and is temporarily stored. A return passage 11 is connected to the oil reservoir 10. The return passage 11 is connected to the oil pan 7, and guides lubricating oil that has circulated through the internal combustion engine to the oil pan 7. The connecting portion of the return passage 11 in the oil reservoir 10 is arranged at a position higher than the bottom surface of the oil reservoir 10 so that a certain amount of oil remains in the oil reservoir 10.

  On the wall surface (side wall) between the base end and the distal end of the valve body 1, a relief hole 12 penetrating the wall surface is formed. The relief hole 12 communicates with the return passage 11 described above. Correspondingly, the spool 3 is formed with a communication passage 13 for communicating the first opening 4 and the relief hole 12.

  One end (starting point) of the communication path 13 is disposed at a portion facing the first opening 4 at the base end (bottom surface) of the spool 3. At that time, as shown in FIG. 2, the diameter R <b> 0 of the communication path 13 is formed to be smaller than the diameter R <b> 1 of the first opening 4. In other words, the diameter R1 of the first opening 4 is formed larger than the diameter R0 of the communication path 13.

  The other end (end point) of the communication path 13 is located when the spool 3 is located at the base end in the sliding direction (the position at which the base end (bottom surface) of the spool 3 contacts the base end of the receiving hole 2). It is arrange | positioned in the site | part facing the said relief hole 12 in the side surface. At that time, the relief hole 12 is formed into a long hole along the sliding direction of the spool 3, and when the spool 3 is located at the base end, the bottom of the relief hole 12 (the lowest position in FIG. 1). It is assumed that the part to be formed is opposed to the bottom of the open end of the communication path 13 (the part located at the lowest side in FIG. 1). Further, when the spool 3 is positioned at the tip in the sliding direction (a position where a coil spring 15 to be described later is fully contracted), the upper end of the relief hole 12 is lower than the opening end of the communication passage 13 (see FIG. The relief hole 12 is formed to be blocked by the side surface of the spool 3.

  In the accommodation hole 2, a coil spring 15 is accommodated in a space (storage chamber) 14 between the distal end of the accommodation hole 2 and the distal end of the spool 3. The coil spring 15 corresponds to a biasing member according to the present invention, and biases the spool 3 from the distal end side to the proximal end side of the accommodation hole 2.

  Next, the operation of the relief mechanism in the present embodiment will be described. First, when the internal combustion engine is in an operation stop state (oil pump 6 is in a stop state), the pressure of the lubricating oil discharged from the oil pump 6 does not act on the spool 3. Receive only power. As a result, as shown in FIG. 1 described above, the bottom surface of the spool 3 comes into contact with the proximal end of the accommodation hole 2.

  When the bottom surface of the spool 3 is in contact with the proximal end of the accommodation hole 2, the first opening 4 and the relief hole 12 are brought into conduction through the communication path 13. That is, the oil passage 5 is connected to the return passage 11. Further, in the storage chamber 14 which is a space between the upper surface of the spool 3 and the tip of the accommodation hole 2, the lubricating oil collected in the oil reservoir 10 during the operation of the internal combustion engine opens the orifice 9 and the second opening 8. Into the storage chamber 14.

  When the internal combustion engine is started in such a state, the oil pump 6 pumps up the lubricating oil in the oil pan 7 and discharges it to the oil passage 5. The lubricating oil discharged from the oil pump 6 to the oil passage 5 is supplied to the main gallery of the internal combustion engine. At this time, if the temperature of the lubricating oil is low, the viscosity of the lubricating oil increases. As the viscosity of the lubricating oil increases, the flow resistance of the lubricating oil from the oil pump 6 toward the main gallery increases. When the flow resistance of the lubricating oil increases, the back pressure acting on the oil pump increases, and the output loss of the internal combustion engine accompanying the drive of the oil pump 6 increases.

  On the other hand, according to the relief mechanism in the present embodiment, a part of the lubricating oil discharged from the oil pump 6 passes from the oil passage 5 through the first opening 4, the communication passage 13, and the relief hole 12. Since it flows to the return passage 11, a situation in which the back pressure acting on the oil pump 6 becomes excessively high can be avoided. As a result, when the viscosity of the lubricating oil is high, such as immediately after the internal combustion engine is cold-started, the output loss of the internal combustion engine associated with driving of the oil pump 6 can be reduced.

  A part of the lubricating oil supplied from the oil pump 6 to the first opening 4 flows into the communication passage 13, but the remaining lubricating oil moves the spool 3 from the proximal end side to the distal end side of the accommodation hole 2. Functions as hydraulic oil to be pressed. When the pressure of the hydraulic oil becomes larger than the urging force of the coil spring 15, the spool 3 starts to be displaced toward the tip side while being separated from the base end of the accommodation hole 2 as shown in FIG. 3. At this time, since the relief hole 12 is formed into a long hole in the sliding direction of the spool 3, the relief passage 12 and the relief are relieved until the spool 3 reaches the distal end side displacement position (position where the coil spring 15 is fully retracted). The conductive state with the hole 12 (conductive state between the first opening 4 and the relief hole 12) is maintained.

  Thereafter, when the spool 3 reaches the displacement end on the front end side, the position of the opening end of the communication path 13 and the position of the relief hole 12 are relatively displaced as shown in FIG. The continuity with is interrupted. That is, the flow of lubricating oil from the oil passage 5 to the return passage 11 through the first opening 4, the communication passage 13, and the relief hole 12 is blocked. As a result, the entire amount of lubricating oil discharged from the oil pump 6 to the oil passage 5 is supplied to the main gallery of the internal combustion engine.

  By the way, if the conduction state between the communication passage 13 and the relief hole 12 is cut off before the viscosity of the lubricating oil is sufficiently lowered, the back pressure acting on the oil pump 6 is increased. There is a possibility that the output loss of the internal combustion engine becomes large. On the other hand, if the conduction state between the communication path 13 and the relief hole 12 continues even after the viscosity of the lubricating oil has sufficiently decreased, there is a possibility that the lubricating oil supplied to the internal combustion engine will be insufficient. If the amount of oil supplied to the internal combustion engine is insufficient, an oil film having a sufficient thickness may not be formed on the lubricated portion of the internal combustion engine, or a device that operates using hydraulic pressure (for example, a hydraulic variable valve mechanism) Etc.) may not work properly.

On the other hand, according to the relief mechanism of the present embodiment, the volume of the storage chamber 14 decreases in accordance with the amount of displacement of the spool 3 in the process in which the spool 3 is displaced from the proximal end to the distal end of the accommodation hole 2. . When the volume of the storage chamber 14 decreases, the oil in the storage chamber 14 is discharged (backflowed) to the oil reservoir 10 through the second opening 8 and the orifice 9. Since the amount of lubricating oil remaining in the oil reservoir 10 is constant, the amount of lubricating oil that accumulates in the storage chamber 14 when the operation of the internal combustion engine is stopped is also constant.

  Therefore, the time required for the spool 3 to move from the proximal end to the distal end of the accommodation hole 2 (the conduction time between the first opening 4 and the relief hole 12) is transferred from the storage chamber 14 to the oil reservoir 10 through the orifice 9. It will vary depending on the flow rate of the lubricating oil being discharged. In other words, the displacement speed of the spool 3 varies depending on the flow rate of the lubricating oil that passes through the orifice 9 per unit time (the magnitude of the flow resistance when the lubricating oil passes through the orifice 9).

  The flow rate of the lubricating oil that passes through the orifice 9 per unit time varies depending on the viscosity of the lubricating oil. For example, when the viscosity of the lubricating oil is high, the flow rate of the lubricating oil passing through the orifice 9 per unit time is smaller than when the viscosity is low. Therefore, the displacement speed of the spool 3 when the viscosity of the lubricating oil is high is slower than when the viscosity of the lubricating oil is low. Therefore, when the viscosity of the lubricating oil is high, the conduction time between the first opening 4 and the relief hole 12 is longer than when the viscosity is low. As a result, it is possible to avoid a situation where the relief hole 12 is blocked before the viscosity of the lubricating oil is sufficiently lowered.

  On the other hand, when the viscosity of the lubricating oil is low, the flow rate of the lubricating oil passing through the orifice 9 per unit time is higher than when the viscosity is high. Therefore, the displacement speed of the spool 3 when the viscosity of the lubricating oil is low is faster than when the viscosity of the lubricating oil is high. Therefore, when the viscosity of the lubricating oil is low, the conduction time between the first opening 4 and the relief hole 12 is shorter than when the viscosity is high. In other words, when the oil viscosity is low, the relief hole 12 is shut off earlier than when it is high. As a result, it is possible to avoid a situation in which the relief hole 12 is not blocked even after the viscosity of the lubricating oil is sufficiently lowered (a situation in which the relief hole 12 continues to open).

  As described above, according to the relief mechanism for lubricating oil of this embodiment, the shutoff timing of the relief hole 12 is automatically adjusted according to the viscosity of the lubricating oil. For this reason, even when the correlation between the temperature and viscosity of the lubricating oil changes due to a change in the properties of the lubricating oil, the output loss of the internal combustion engine accompanying the drive of the oil pump 6 increases, or the supply to the internal combustion engine It is possible to avoid a situation where the lubricating oil to be used is insufficient.

  The orifice 9 may be a temperature-sensitive variable orifice that can change the cross-sectional area of the passage according to the temperature of the lubricating oil. Specifically, the orifice 9 may be configured so that the passage cross-sectional area is smaller when the temperature of the lubricating oil is low than when it is high. In this case, when the temperature of the lubricating oil is low and the viscosity of the lubricating oil is high, the conduction time between the first opening 4 and the relief hole 12 can be reliably lengthened, and the temperature of the lubricating oil is high. In addition, when the viscosity of the lubricating oil is low, the conduction time between the first opening 4 and the relief hole 12 can be reliably shortened. As a result, it is possible to more reliably avoid a situation in which the output loss of the internal combustion engine due to the drive of the oil pump 6 becomes large or a situation in which the lubricating oil supplied to the internal combustion engine is insufficient.

<Example 2>
Next, a second embodiment of the present invention will be described with reference to FIG. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, the configuration in which the proximal end of the coil spring 15 is in contact with the upper surface of the spool 3 has been described. However, in this embodiment, the proximal end of the coil spring 15 is the outer periphery of the spool 3 and the receiving hole 2. An example of insertion between the inner peripheral surface will be described.

  FIG. 5 is a diagram showing the configuration of the lubricating oil relief mechanism in the present embodiment. In FIG. 5, the same reference numerals are given to the same configurations as those of the first embodiment described above. As shown in FIG. 5, a small diameter portion 30 having a smaller diameter than the proximal end side of the spool 3 is formed at the distal end of the spool 3. A base end of the coil spring 150 is fitted between the outer peripheral surface of the small diameter portion 30 and the inner peripheral surface of the accommodation hole 2. At that time, the coil spring 150 is formed so that the inner diameter of the coil spring 150 is substantially the same as the outer diameter of the small diameter portion 30 and the outer diameter of the coil spring 150 is substantially the same as the inner diameter of the receiving hole 2. Shall be. The coil spring 150 has a function of urging the spool 3 from the distal end side toward the proximal end side, similarly to the coil spring 15 of the first embodiment described above.

  According to the relief mechanism configured as described above, when the coil spring 150 contracts due to the displacement from the proximal end side to the distal end side of the spool 3, the coil spring 150 tends to expand in the radial direction. The contact load between 150 and the inner peripheral surface of the accommodation hole 2 increases. As a result, in addition to the same effects as those of the first embodiment described above, it is possible to obtain an effect that the sealing performance between the outer peripheral surface of the spool 3 and the inner peripheral surface of the accommodation hole 2 can be improved.

  In the first to second embodiments described above, the relief mechanism provided with the dedicated valve body is exemplified, but the cylinder block of the internal combustion engine may also serve as the valve body. That is, an accommodation hole may be provided in the cylinder block, and the spool may be accommodated in the accommodation hole.

DESCRIPTION OF SYMBOLS 1 Valve body 2 Accommodating hole 3 Spool 4 1st opening part 5 Oil passage 6 Oil pump 7 Oil pan 8 2nd opening part 9 Orifice 10 Oil sump 11 Return passage 12 Relief hole 13 Communication path 14 Storage chamber 15 Coil spring 30 Small diameter part 150 coil spring

Claims (2)

A relief mechanism provided in a path through which lubricating oil for an internal combustion engine circulates,
A valve body in which an accommodation hole for slidably accommodating the spool is formed;
A first opening provided at a proximal end of the valve body in a sliding direction of the spool and communicating an oil passage from an oil pump to the internal combustion engine and the accommodation hole;
A second opening provided at the tip of the valve body in the sliding direction of the spool and communicating the oil reservoir provided in the internal combustion engine and the accommodation hole;
A relief hole provided on a wall surface between a base end and a distal end of the valve body, and communicating with the accommodation hole upstream from the oil pump;
When the spool is located at the proximal end in the sliding direction, the first opening communicates with the relief hole, and when the spool is located at the distal end in the sliding direction, the first opening is provided. A communication path for blocking the opening and the relief hole;
An urging member for urging the spool toward the proximal end in the sliding direction;
An orifice provided between the second opening and the oil reservoir;
A relief mechanism for lubricating oil comprising:   2. The lubrication oil relief mechanism according to claim 1, wherein the orifice is a variable orifice whose passage cross-sectional area is larger when the temperature of the lubrication oil is higher than when the temperature is lower.

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