JP2010116822A - Lubricating device for valve train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide effective lubrication with a small amount of lubricating oil in a lubricating device for a valve train. <P>SOLUTION: The lubricating device 1 for the valve train includes a camshaft 2 including a cam 4 for opening and closing a valve 3, an oil pocket 5 formed inside of the camshaft 2, an oiling hole 6 opening at an outer circumference surface of a cam 4, an oil passage 7 providing communication between the oiling hole 6 and the oil pocket 5, and an intermittent oiling device making lubricating oil intermittently flow into the oil pocket 5. The oil passage 7 includes a bending part 71 bending at 90° degrees or less in a middle thereof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lubricating device for a valve operating mechanism.

  As a lubrication device for a valve mechanism of an internal combustion engine, a device using an internal oil supply type hollow camshaft is known. Such a hollow camshaft has a hollow portion and an oil supply hole that communicates with the hollow portion and opens on the outer peripheral surface of the cam, as described in, for example, Patent Document 1 below. When the lubricating oil is fed into the hollow portion of the camshaft, the lubricating oil is injected from the oil supply hole. Thereby, the sliding surface of a cam and its driven node can be lubricated.

JP-A-9-250626 JP 2003-35119 A Japanese Utility Model Publication No. 7-30305 Japanese Utility Model Publication No. 5-77512

  In recent years, there has been an increasing demand for improved fuel efficiency for automobiles. In order to meet such demands, it is required to make the oil pump as small as possible and to make the power consumption by the oil pump as small as possible.

  In the conventional lubricating device, from the viewpoint of reducing the capacity of the oil pump, it is inefficient to always inject the lubricating oil from the oil supply hole of the cam. This is because when the cam angle is such that the lubricant injected from the oil supply hole does not hit the follower of the cam, the lubricant is injected unnecessarily, and the flow rate of the oil increases unnecessarily.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lubrication device for a valve mechanism that can be efficiently lubricated with a small amount of lubricating oil.

In order to achieve the above object, a first invention is a lubricating device for a valve operating mechanism,
A camshaft having a cam for opening and closing the valve;
An oil reservoir formed inside the camshaft;
An oiling hole opening in the outer peripheral surface of the cam;
An oil passage communicating the oil supply hole and the oil reservoir;
An intermittent oil supply device for intermittently flowing lubricating oil into the oil reservoir;
With
The oil passage has at least one curved portion that bends at an angle of 90 ° or less in the middle thereof.

The second invention is the first invention, wherein
The camshaft is manufactured by assembling a cam and a shaft constituted by different members,
A part of the oil passage is formed by a groove provided on the outer peripheral surface of the shaft before assembly.

  According to the first invention, the lubricating oil can be intermittently flowed into the oil reservoir formed inside the camshaft. For this reason, during one rotation of the camshaft, it is possible to inject the lubricating oil only in the angular range where the lubricating oil needs to be injected from the oil supply hole, and to stop the injection of the lubricating oil in the other ranges. For this reason, the amount of lubricating oil flowing out can be greatly reduced, and the capacity of the oil pump can be reduced. According to the first aspect of the invention, the injection of the lubricating oil is stopped by providing the curved portion that bends at an angle of 90 ° or less in the middle of the oil passage that communicates the oil reservoir and the oil supply hole. In the oil supply stop range, it is possible to reliably prevent the lubricating oil from being discharged from the oil supply hole by centrifugal force. Therefore, it is possible to reliably prevent a gap from being generated in the oil reservoir. For this reason, when entering the oil supply range, the lubricating oil can be injected from the oil supply hole without delay. That is, the lubricating oil can be injected at an accurate timing.

  According to the second aspect of the present invention, when a camshaft is manufactured by assembling a cam and a shaft constituted by different members, a part of the oil passage is formed by forming a groove on the outer peripheral surface of the shaft before assembly. Can be configured. Thereby, an oil path can be formed by simple processing and can be easily manufactured.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional side view showing a lubricating device (hereinafter simply referred to as “lubricating device”) for a valve operating mechanism according to Embodiment 1 of the present invention. The lubrication apparatus shown in FIG. 1 lubricates a valve operating mechanism that drives an intake valve or an exhaust valve of an internal combustion engine (hereinafter referred to as an engine).

  A lubricating device 1 shown in FIG. 1 includes a camshaft 2. The camshaft 2 has a cam 4 for opening and closing the valve 3. The valve 3 is an intake valve or an exhaust valve. The camshaft 2 in FIG. 1 is represented as a cross-sectional view at the position of the cam 4. The camshaft 2 is driven by the crankshaft of the engine and rotates clockwise in FIG. 1 at half the speed of the crankshaft.

  The center portion of the camshaft 2 is hollow. This hollow portion constitutes an oil reservoir 5 in which lubricating oil is accumulated. An oil supply hole 6 is opened on the outer peripheral surface of the cam 4. The oil supply hole 6 and the oil reservoir 5 communicate with each other via an oil passage 7. The oil passage 7 has a curved portion 71 that bends at an angle of 90 ° or less in the middle thereof. That is, the oil passage 7 has a first straight portion 72 that extends from the oil reservoir 5 and reaches the curved portion 71, and a second straight portion 73 that extends from the curved portion 71 and reaches the oil supply hole 6. . And the angle which the 1st linear part 72 and the 2nd linear part 73 make is 90 degrees or less. In particular, in the illustrated configuration, the angle formed by the first straight line portion 72 and the second straight line portion 73 is 45 ° or less.

  In FIG. 1 and FIGS. 2 to 5 described later, the shaded portion represents the lubricating oil.

  A rocker arm 8 is disposed below the cam 4. One end of the rocker arm 8 is in contact with the end of the stem 31 of the valve 3. The other end of the rocker arm 8 is supported by a hydraulic lash adjuster 9. A roller 10 that can be rotated smoothly is installed at an intermediate portion of the rocker arm 8. The cam 4 is in contact with the roller 10.

  When the cam 4 presses the roller 10, the rocker arm 8 rotates around the end portion on the hydraulic lash adjuster 9 side. As a result, the rocker arm 8 presses the stem 31 of the valve 3, and the valve 3 opens (lifts). The valve 3 is urged in the closing direction by a valve spring 11. When the rocker arm 8 returns to the original position, the valve 3 is closed by the urging force of the valve spring 11.

  As will be described later, the lubricating device 1 can lubricate the contact surface between the cam 4 and the roller 10 and the bearing of the roller 10 by injecting the lubricating oil from the oil supply hole 6.

  FIG. 2 is a cross-sectional view for explaining the intermittent fueling device 12 included in the lubricating device 1 of the present embodiment. The camshaft 2 is provided with a plurality of journals that are parts supported by the bearings. The camshaft 2 in FIG. 2 is represented as a cross-sectional view at the position of one journal 13 among a plurality of journals.

  The journal 13 is supported by a bearing 14. The bearing 14 includes a semicircular inner peripheral surface (sliding surface) formed on the cam carrier 15 and a semicircular inner peripheral surface (sliding surface) formed on the cam cap 16. .

  An oil passage 17 is formed inside the cam carrier 15. The outlet of the oil passage 17 is open to the inner peripheral surface of the bearing 14. The oil passage 17 is connected to an engine oil circulation route. That is, the oil path 17 is supplied with lubricating oil that is pumped by an engine oil pump (not shown).

  The oil reservoir 5 described above is continuously formed up to the inside of the journal 13. Grooves 18 along the circumferential direction are formed on the outer peripheral surface of the journal 13 over a predetermined angle. An oil passage 19 communicates between the bottom surface of the groove 18 and the oil reservoir 5.

  When the groove 18 and the outlet of the oil passage 17 are opposed to each other, that is, in the state shown in FIG. 2, the lubricating oil fed to the oil passage 17 flows into the oil reservoir 5 through the oil passage 19. . As a result, the oil pressure in the oil reservoir 5 rises, and the lubricating oil is injected from the oil supply hole 6 of the cam 4.

  On the other hand, when the outlet of the oil passage 17 and the groove 18 are not opposed to each other, the inflow of the lubricating oil into the oil reservoir 5 is stopped. For this reason, lubricating oil is not injected from the oil supply hole 6 of the cam 4.

  According to the intermittent oil supply device 12 as described above, the lubricating oil can be intermittently supplied to the oil reservoir 5 as the camshaft 2 rotates. That is, during one rotation of the camshaft 2, the lubricating oil flows from the oil passage 17 into the oil reservoir 5 only when the groove 18 and the outlet of the oil passage 17 face each other, and the oil supply hole of the cam 4 Lubricating oil is injected from 6. Outside the predetermined angle range, the injection of lubricating oil from the oil supply hole 6 of the cam 4 stops. In the following description, the predetermined angle range, that is, a range in which the groove 18 and the outlet of the oil passage 17 face each other and the lubricating oil is injected from the oil supply hole 6 is referred to as an “oil supply range”. Further, a range other than the oil supply range, that is, a range in which the injection of the lubricating oil from the oil supply hole 6 stops is referred to as an “oil supply stop range”.

  FIG. 3 is a diagram showing the oil supply range by the position of the oil supply hole 6. In FIG. 3, for convenience, the cams 4 at the positions at both ends of the oil supply range are drawn in an overlapping manner. As shown in FIG. 3, a range where the oil supply hole 6 faces the roller 10 is an oil supply range. In this range, lubricating oil is injected from the oil supply hole 6. For this reason, the contact surface between the cam 4 and the roller 10 and the bearing of the roller 10 can be reliably and reliably lubricated with a minimum amount of lubricating oil.

  On the other hand, FIG. 4 is a diagram showing the refueling stop range by the position of the refueling hole 6. As shown in FIG. 4, a range where the oil supply hole 6 does not face the roller 10 is an oil supply stop range, and the injection of the lubricating oil from the oil supply hole 6 is stopped. That is, in a range where the lubricating oil injected from the oil supply hole 6 does not hit the roller 10, the injection of the lubricating oil from the oil supply hole 6 is stopped. For this reason, since the amount of the lubricating oil flowing out from the oil passage 17 can be greatly reduced, the capacity of the oil pump can be reduced.

  Moreover, in this embodiment, the oil supply hole 6 is formed in the base circle part of the cam 4, and is arrange | positioned with respect to the cam peak at the front side of a rotation direction. Thereby, the lubricating oil can be sprayed onto the roller 10 immediately before the cam crest of the cam 4 presses the roller 10. For this reason, immediately before a load (pressure) is applied between the cam 4 and the roller 10, an oil film can be reliably formed between them, and lubrication can be performed particularly effectively.

  Further, in such a lubrication apparatus 1, the curved portion 71 as described above is provided in the middle of the oil passage 7 that communicates the oil reservoir 5 inside the camshaft 2 and the oil supply hole 6. It is possible to reliably suppress the lubricating oil from being discharged from the oil supply hole 6 due to the action of centrifugal force. In order to facilitate understanding of this effect, a comparative example will be described first.

  FIG. 5 is a cross-sectional view of the cam 90 included in the cam shaft of the comparative example. An oil supply hole 91 that opens to the outer peripheral surface of the cam 90 communicates with an oil reservoir 93 through an oil passage 92. The oil passage 92 linearly connects the oil supply hole 91 and the oil reservoir 93. When the cam 90 rotates, a centrifugal force acts on the lubricating oil in the oil passage 92. The centrifugal force increases as the rotational speed of the cam 90 increases. When the position of the oil supply hole 91 is within the oil supply stop range, the inflow of the lubricating oil into the oil reservoir 93 is stopped, so that the injection of the lubricating oil from the oil supply hole 91 is normally stopped. However, when the rotational speed of the cam 90 is fast, the lubricating oil in the oil passage 92 may jump out of the oil supply hole 91 due to the centrifugal force even when the oil supply hole 91 is in the oil supply stop range. is there. When the lubricating oil in the oil passage 92 jumps out, the lubricating oil in the oil reservoir 93 is also drawn into the oil passage 92 and further jumps out. As a result, a gap 94 is generated in the oil reservoir 93.

  When the air gap 94 is generated in the oil reservoir 93, there are the following problems. When the oil supply hole 91 next enters the oil supply range and the lubricating oil is supplied into the oil reservoir 93, the lubricating oil is first filled into the gap 94, and after filling the gap 94, flows into the oil passage 92. And it ejects from the oil supply hole 91. That is, even if the oil supply hole 91 enters the oil supply range, the lubricating oil is not injected from the oil supply hole 91 immediately, and the injection is started with a delay in timing. For this reason, the lubricating oil is not sufficiently supplied to the roller 10 and the lubrication is incomplete.

  On the other hand, in the lubricating device 1 of this embodiment, even if the rotational speed of the cam 4 is high, the discharge of the lubricating oil from the oil supply hole 6 can be suppressed as follows. As shown in FIG. 4, even if centrifugal force acts on the lubricating oil in the first linear portion 72 of the oil passage 7 in the oil supply stop range, the radially outward direction of the first linear portion 72 is curved. Blocked by the portion 71. Therefore, the lubricating oil in the first straight portion 72 is not discharged by centrifugal force. Therefore, in the lubrication apparatus 1, even if a part of the lubricating oil in the second linear portion 73 of the oil passage 7 is discharged in the oil supply stop range, the lubricating oil in the first linear portion 72 is discharged. It will not be discharged. Therefore, it is possible to reliably prevent a gap from being generated in the oil reservoir 5. For this reason, when the oil supply hole 6 enters the oil supply range, the lubricating oil can be injected from the oil supply hole 6 without delay. Thereby, lubricating oil can be injected with exact timing. Even if there is a gap in the second straight line portion 73, since the volume of this portion is small, there is no problem because the delay in the injection timing of the lubricating oil is small.

  In the present invention, if the angle of the curved portion 71 (the angle formed by the upstream portion and the downstream portion sandwiching the curved portion 71) is 90 ° or less, the above effect can be obtained. More preferably, it is 60 ° or less, and further preferably 45 ° or less. As the angle of the curved portion 71 is reduced, the discharge of the lubricating oil from the oil supply hole 6 in the oil supply stop range can be more reliably prevented.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 6 to FIG. 8. The description will focus on the differences from the first embodiment described above, and the same matters will be described. Simplify or omit.

  FIG. 6 is a perspective view showing the camshaft 40 of the present embodiment. As shown in FIG. 6, the camshaft 40 of the present embodiment is an assembly type camshaft manufactured by assembling a shaft 41 and a cam 42. The cam 42 has a circular shaft insertion hole 43 into which the shaft 41 is inserted. The cam 42 is fixed to the shaft 41 by press-fitting the shaft 41 into the shaft insertion hole 43. In FIG. 6, two cams are depicted, the cam 42 before being fixed to the shaft 41 and the cam 42 after being fixed.

  The cam 42 is formed with an oil supply hole 44 that opens on the outer peripheral surface (preferably on the base circle) and a through hole 45 that communicates with the oil supply hole 44. The through hole 45 penetrates to the inner peripheral surface of the shaft insertion hole 43. The through hole 45 is formed along the tangential direction of the inner peripheral surface of the shaft insertion hole 43.

  The shaft 41 has a hollow portion, and an oil reservoir 46 is constituted by the hollow portion. A groove 47 extending in the circumferential direction is formed on the outer peripheral surface of the shaft 41 before assembly. A through hole 48 that penetrates to the oil reservoir 46 is formed at one end of the groove 47. After the shaft 41 and the cam 42 are assembled, the groove 47 is hidden under the cam 42 and the other end of the groove 47 and the through hole 45 communicate with each other.

  FIG. 7 is a cross-sectional view showing a state where the camshaft 40 of the present embodiment is in the oil supply range. As shown in FIG. 7, in the camshaft 40 formed by assembling the shaft 41 and the cam 42, an oil path from the oil reservoir 46 to the oil supply hole 44 is established by connecting the through hole 45, the groove 47, and the through hole 48. Is configured. In the middle of the oil passage, a first bent portion 50 is formed between the through hole 45 and the groove 47, and a second bent portion 51 is formed between the groove 47 and the through hole 48. In the configuration shown in the drawing, the first curved portion 50 forms an angle of 45 ° or less, and the second curved portion 51 forms an angle of 90 °.

  FIG. 8 is a cross-sectional view showing a state where the camshaft 40 of the present embodiment is in the oil supply stop range. According to the present embodiment, similarly to the first embodiment described above, even when the rotational speed of the camshaft 40 is high, the discharge of the lubricating oil from the oil supply hole 44 is reliably suppressed in the oil supply stop range. be able to. That is, as shown in FIG. 8, when in the oil supply stop range, the lubricating oil on the downstream side (through hole 45) from the first curved portion 50 may be discharged by the centrifugal force in the camshaft 40. It is reliably suppressed that the lubricating oil upstream of the first curved portion 50 is discharged. Therefore, since it is possible to reliably prevent the gap from being generated in the oil reservoir 46, the lubricating oil can be injected from the oil supply hole 44 without delay when entering the oil supply range.

  In particular, in the camshaft 40 of the present embodiment, the second curved portion 51 is further provided in addition to the first curved portion 50, so that the lubricating oil can be more reliably discharged when in the oil supply stop range. Can be suppressed.

  In the present embodiment, the through hole 45 of the cam 42 and the groove 47 and the through hole 48 of the shaft 41 can be easily formed by simple machining or the like. For this reason, since the oil path inside the camshaft 40 can be easily provided, the manufacture is easy and the cost can be reduced.

It is a cross-sectional side view which shows the lubricating device of the valve operating mechanism of Embodiment 1 of this invention. It is sectional drawing for demonstrating the intermittent oil supply apparatus with which the lubricating device of Embodiment 1 of this invention is provided. It is the figure which represented the oil supply range by the position of the oil supply hole. It is the figure which represented the refueling stop range with the position of the fueling hole. It is sectional drawing of the cam with which the cam shaft of a comparative example is provided. It is a perspective view which shows the cam shaft of Embodiment 2 of this invention. It is sectional drawing which shows the state which the camshaft of Embodiment 2 of this invention exists in an oil supply range. It is sectional drawing which shows the state which the camshaft of Embodiment 2 of this invention exists in an oil supply stop range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lubricator 2 Camshaft 3 Valve 31 Stem 4 Cam 5 Oil reservoir 6 Oil supply hole 7 Oil path 71 Curved part 72 First linear part 73 Second linear part 8 Rocker arm 9 Hydraulic lash adjuster 10 Roller 11 Valve spring 12 Intermittent Oil supply device 13 Journal 14 Bearing 15 Cam carrier 16 Cam cap 17 Oil passage 18 Groove 19 Oil passage 40 Cam shaft 41 Shaft 42 Cam 43 Shaft insertion hole 44 Oil supply hole 45 Through hole 46 Oil reservoir 47 Groove 48 Through hole 50 First curve Part 51 Second music part

Claims (2)

A camshaft having a cam for opening and closing the valve;
An oil reservoir formed inside the camshaft;
An oiling hole opening in the outer peripheral surface of the cam;
An oil passage communicating the oil supply hole and the oil reservoir;
An intermittent oil supply device for intermittently flowing lubricating oil into the oil reservoir;
With
The oil passage has at least one curved portion that bends at an angle of 90 ° or less in the middle of the oil passage. The camshaft is manufactured by assembling a cam and a shaft constituted by different members,
2. The lubricating device for a valve operating mechanism according to claim 1, wherein a part of the oil passage is formed by a groove provided on an outer peripheral surface of the shaft before assembly.

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