JP4142564B2 - Rocker shaft oil passage structure - Google Patents

Description

  The present invention relates to an oil passage structure of a rocker shaft, and more particularly to an oil passage structure of a rocker shaft for constituting a hydraulic supply / discharge oil passage to a valve operating characteristic switching mechanism that operates hydraulically.

  As an aid for understanding the oil passage structure of the rocker shaft according to the present invention, first, a valve operation characteristic switching mechanism of an internal combustion engine to which the present invention is applied will be briefly described.

  As shown in FIGS. 9 and 10, the valve operating characteristic switching mechanism includes a low-speed cam 2 and a high-speed cam 3 having different operating angles and lift amounts, and a perfect circle portion having a diameter equal to the base circle of both cams 2 and 3. 4, the intake camshaft 1 integrally formed adjacent to each other, the rocker shaft 5 extending in parallel with the camshaft 1 below the intake camshaft 1, the low-speed cam 2, the high-speed cam 3, and the true Three rocker arms 6 a, 6 b, and 7 that are pivotally supported by a rocker shaft 5 corresponding to the circular portion 4 are provided.

  The stem ends of the two intake valves 8a and 8b, which are urged to close, are in contact with the free ends of the low-speed rocker arms 6a and 6b corresponding to the low-speed cam 2 and the perfect circle part 4, respectively. The high-speed rocker arm 7 corresponding to the high-speed cam 3 is spring-biased so that the sliding contact state with the high-speed cam 3 is always maintained.

  In the guide holes 9, 11, 13 formed in the three rocker arms 6 a, 6 b, 7, there is provided a connection switching mechanism VT comprising three pins 10, 12, 14 for switching between the low speed mode and the high speed mode. It has been.

  The rocker shaft 5 is provided with two oil passages 16a and 16b for pumping the lubricating oil pumped up from the oil pan as hydraulic oil. By switching the direction of the hydraulic pressure applied to each end of the connection switching mechanism VT from these oil passages with the solenoid valves, the pins 10, 12, and 14 are aligned with the guide holes 9, 11, and 13, respectively. The rocker arms 6a, 6b, and 7 can be displaced relative to each other, and the low-speed cam 2 is driven to open only one intake valve 8a (see FIG. 9), and the pins 10, 12, and 14 are adjacent to each other. The three rocker arms 6a, 6b, 7 are connected to each other and can swing together, and the intake valves 8a, 8b are opened by the high-speed cam 3. The mode is switched to the driven high speed mode (see FIG. 10).

  When driving such a double-acting hydraulic drive plunger, at least two independent oil passages 16a and 16b are required. If it is desired to make the valve timing between cylinders different from each other, the number of oil passages increases in accordance with the type of switching mode.

As a method of forming a plurality of oil passages in the rocker shaft, a pipe member having a part of the outer peripheral surface recessed along the axis is press-fitted into a hollow rocker shaft, the inside of the pipe, and the depression of the pipe There is known one in which a plurality of oil passages are formed between the outer surface and the inner peripheral surface of the axial hole of the rocker shaft (see Patent Document 1). In addition to this, a structure in which a plurality of inner tube members are bundled and inserted inside the rocker shaft is known (see Patent Document 2).
JP-A-8-61018 JP 2000-170506 A

  However, the technique disclosed in Patent Document 1 has a low degree of freedom in the cross-sectional shape of the pipe member and it is difficult to make the cross-sectional areas of the plurality of oil passages uniform. Moreover, since the method disclosed in Patent Document 2 is fixed in the axial hole of the rocker shaft by bringing a plurality of inner tube members into contact with each other, it is easily affected by deformation of adjacent inner tube members. It has been difficult to press-fit the plurality of inner pipe members into the axial holes at the same time while accurately positioning the inner pipe members.

  The oil passage along the axis from one shaft end of the solid shaft was drilled, the rocker shaft was formed as a hollow shaft, and the cross-sectional shape was formed by extrusion molding into an X shape or Y shape It may be possible to press-fit a rod into the hollow hole and partition the cross section of the axial hole into a plurality of fan-shaped parts, but drilling is difficult to form a long oil passage, and the partition plate is a rocker shaft. Since the contact area with the inner peripheral surface of the axial hole is small, it is difficult to prevent leakage over the entire length in the axial direction.

When such a problem is solved and the inner pipe member is provided inside the rocker shaft to constitute a plurality of oil passages, the plurality of inner pipe members are relatively easily positioned and fixed without affecting each other. In order to provide a rocker shaft oil passage structure, the rocker shaft oil passage structure according to the present invention is a rocker shaft for swingably supporting a rocker arm that drives a valve provided in a combustion chamber of an internal combustion engine. (21) An oil passage structure, wherein an axial hole (22) formed inside the rocker shaft, a plurality of inner pipe members (24) inserted into the axial hole, and the inner pipe A fixing member (25) for fixing the member in the axial hole, and when the plurality of inner tube members are bundled, a gap (27) along the axial direction is formed at the center thereof. The fixing member has a rod shape. Then, it is press-fitted into the gaps of the plurality of inner tube members inserted and bundled into the axial hole, and the press-fitting force against the inner peripheral surface of the axial hole is caused by the press-fitting. The inner tube member is fixed in the axial hole by acting on the diameter line.

The rocker shaft oil passage structure according to the present invention is a rocker shaft oil passage structure for swingably supporting a rocker arm that drives a valve provided in a combustion chamber of an internal combustion engine. Each axial hole formed inside and the outer contour when bundled are approximately equal to the cross-sectional contour of the axial hole, and when bundled, each piece was formed so that a gap along the axial direction was opened at the center. A plurality of inner tube members, and after the plurality of inner tube members are bundled and inserted into the axial hole, a fixing member for fixing the inner tube member to the axial hole is press-fitted into the gap. Was characterized.

In the oil passage structure of the rocker shaft according to the present invention, preferably, a surface of the inner pipe member facing the fixing member forming the gap forms an arcuate concave surface (28) .

The oil passage structure of the rocker shaft according to the present invention is preferably provided with a lid member (29) having a convex portion (31) fitted to an axial end portion of the plurality of inner tube members, and the inner tube of the convex portion. A projecting end into the member is positioned inward of the axial hole from the end of the fixing member on the lid member side.

According to the oil passage structure of the rocker shaft according to the present invention , since the fixing member that presses the inner pipe member radially against the inner peripheral surface of the axial hole is provided, a plurality of inner pipe members are provided in the axial hole. In addition, the inner pipe member is sandwiched between the inner peripheral surface of the axial hole and the fixing member on the diameter line of the axial hole, and the plurality of inner pipe members are easily positioned and fixed without affecting each other. be able to.

Further , according to the oil passage structure of the rocker shaft according to the present invention , before the fixing member is press-fitted, the plurality of inner tube members can move relatively easily in the axial hole, and the positioning is easy. Since the stress when the fixing member is attached by press fitting is absorbed by the deformation of the inner tube member, the deformation does not reach the outer peripheral surface of the hollow shaft. In addition to these, since the radius of curvature of the outer peripheral surface of the fixing member is small, the contact area when press-fitting into the central portion where a plurality of inner tube members are bundled is reduced, and sliding resistance can be reduced.

Further , according to the oil passage structure of the rocker shaft according to the present invention, the inner pipe member is fixed by the fixing member and the axial hole, so that the fixing becomes easy, and finally, the fixing member is press-fitted into the gap. Since the tube member is fixed, a sliding portion at the time of press-fitting is formed between the inner tube member and the fixing member, and deformation of the rocker shaft due to stress can be suppressed.

Further , according to the oil passage structure of the rocker shaft according to the present invention, the concave portion is formed, so that it becomes a guide for press-fitting the fixing member and the positioning of the inner pipe member is facilitated.

Further , according to the oil passage structure of the rocker shaft according to the present invention , it is possible to secure a press-fitting allowance of the convex portion to the end portions of the plurality of inner tube members, and to perform positioning and end blockage of the plurality of inner tube members It can be done easily and reliably.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a rocker shaft to which the present invention is applied. The rocker shaft 21 includes a hollow shaft 23 having a perfect circular shape in which an axial hole 22 having an appropriate diameter is provided over the entire length, and a plurality of outer contours mounted in the axial hole 22 (for example, a fan shape). The inner pipe member 24 is pressed against the inner peripheral surface of the axial hole 22 in the radial direction of the rocker shaft 21 at the center of the four inner pipe members 24 and the bundled four inner pipe members 24. And a round bar 25 (fixing member) inserted into the axial hole 22 for fixing.

  As shown in FIG. 2, in the rocker shaft 21, first, the bundled four inner pipe members 24 are inserted into the axial hole 22 of the hollow shaft 23 in a predetermined amount, and in this state, the four inner pipe members 24 are inserted. Positioning pins (not shown) are provided in through holes 26a and 26b that are formed in appropriate positions in the hollow shaft 23 and the four inner tube members 24, respectively. The four inner tube members 24 are inserted so as not to be displaced. The through-holes 26a and 26b can be used as hydraulic oil outlets when the pins are removed.

  Here, the inner tube member 24 is formed by, for example, extrusion (pulling) molding, and the outer peripheral contour in a bundled state is substantially a perfect circle, and the outer diameter dimension thereof is relatively in the axial hole 22 of the hollow shaft 23. It is determined so that it can be pushed in with low axial force. Each inner pipe member 24 is formed with a concave surface 28 having an arc shape in order to form a gap 27 at the center of the four inner pipe members 24 when bundled.

  Next, a round bar 25 having a tapered tip is press-fitted into a gap 27 formed at the center of the bundled four inner tube members 24. Here, the inner diameter dimension of the gap 27 formed at the center of the four inner tube members 24 and the outer diameter dimension of the round bar member 25 are determined so as to be an interference fit with each other. Since the surface facing the outer peripheral surface of the material 25 forms an arc-shaped concave surface 28, it is guided by the concave surface 28, and the positioning of the round bar 25 and each inner tube member 24 is easily and reliably performed. Further, since the radius of curvature of the outer peripheral surface of the small-diameter round bar 25 is small, the contact area when press-fitting into the gap 27 at the center of the bundled four inner tube members 24 is reduced, and the sliding resistance is reduced. The press-fitting work is performed smoothly.

  The four inner tube members 24 are pushed outward in the radial direction by the press-fitting of the round bar 25, and the outer peripheral surface of each inner tube member 24 is pressed against the inner peripheral surface of the axial hole 22 of the hollow shaft 23. The inner tube member 24 is integrally coupled to the hollow shaft 23. At the same time, the round bar 25 also presses the outer peripheral surface thereof against the inner peripheral surfaces (concave surfaces 28) of the four inner tube members 24 and is integrally coupled to the four inner tube members 24. At this time, when the round bar member 25 is press-fitted, radial stress passing through the center of the round bar member 25 acts on the four inner pipe members 24, but this is absorbed inside the inner pipe member 24. Therefore, the influence of the pressure input of the round bar 25 does not reach the outer periphery of the rocker shaft 21.

  Finally, as shown in FIG. 3, the cover members 29 are fitted to both axial ends of the rocker shaft 21 in which the four inner tube members 24 are fixed to the axial holes 22 of the hollow shaft 23 by the round bars 25. By doing so, the terminal of the inner pipe member 24 is closed, and the inside can be used as an oil passage.

  As shown in FIG. 4, the lid member 29 includes a disc-shaped portion 30 having an outer diameter dimension substantially equal to that of the hollow shaft 23, and an inner tube member 24 projecting from one surface of the disc-shaped portion 30. It consists of a convex portion 31 having an outer contour equal to the inner peripheral contour, and is fixed by press-fitting the convex portion 31 into the end of the inner tube member 24.

  The convex portion 31 is formed to be somewhat tapered, and the length of the convex portion 31 is the end surface of the convex portion 31 farthest from the disk-shaped portion 30. It is determined so as to be inside in the axial direction from the immersion position at the end in the axial direction. That is, the projection 31 and the lid member side end of the fixing round bar 25 overlap each other in the direction perpendicular to the axis of the rocker shaft 21. As a result, the open end of the inner tube member 24 is expanded and deformed by the press-fitting of the projecting portion 31 to receive the projecting portion 31, and the lid member 29 is integrally and firmly coupled to the inner tube member 24.

  The round bar 25 that is press-fitted into the gap 27 formed at the center of the plurality of inner tube members 24 is not limited to a solid shape, and may be hollow as shown in FIG.

  The number of inner tube members 24 to be inserted into the axial hole 22 can be appropriately determined according to the convenience of the drive object within a practically allowable range. For example, the number of the inner tube members 24 shown in FIG. The cross-sectional shape of the inner tube member 24 is determined so that a gap 32 is formed between the outer peripheral surface of the inner tube member 24 and the inner peripheral surface of the axial hole 22 as shown in FIG. In this case, since the gap 32 can also be used as an oil passage, passages more than the number of the inner pipe members 24 can be formed, and the inner pipe members 24 can be reduced.

  The oil passage forming technique according to the present invention is not limited to the above-described rocker shaft, and can be equally applied to a shaft that requires a plurality of oil passages.

It is sectional drawing orthogonal to the axis line of the rocker shaft to which this invention was applied. It is an implementation point explanatory drawing of this invention. It is sectional drawing which follows the axis line of the edge part of the rocker shaft to which this invention was applied. It is a perspective view of a lid member. It is sectional drawing similar to FIG. 1 which shows a 1st modification. It is sectional drawing similar to FIG. 1 which shows the 2nd modification. It is sectional drawing similar to FIG. 1 which shows a 3rd modification. It is sectional drawing similar to FIG. 1 which shows a 4th modification. It is a schematic mechanism figure which shows the low speed mode state of the conventional valve operating apparatus with a variable operation characteristic apparatus. It is a schematic mechanism figure which shows the high-speed mode state of the conventional valve operating apparatus with a variable operation characteristic apparatus.

Explanation of symbols

22 Axial hole 23 Hollow shaft 24 Inner tube member 25 Round bar material (fixing member)
27 Cavity 28 Concave surface 29 Lid member 31 Projection

Claims (4)

An oil path structure of a rocker shaft for swingably supporting a rocker arm that drives a valve provided in a combustion chamber of an internal combustion engine,
An axial hole formed inside the rocker shaft;
A plurality of inner tube members inserted into the axial hole;
A fixing member for fixing the inner tube member in the axial hole ,
The plurality of inner pipe members are formed such that a gap along the axial direction is vacated at the center when bundled,
The fixing member has a rod shape and is press-fitted into the gaps of the plurality of inner tube members that are inserted and bundled into the axial hole, and is pressed against the inner peripheral surface of the axial hole by the press-fitting. An oil passage structure for a rocker shaft , wherein a force is applied on a diameter line of the axial hole to fix the inner pipe member in the axial hole . An oil path structure of a rocker shaft for swingably supporting a rocker arm that drives a valve provided in a combustion chamber of an internal combustion engine,
The axial hole formed inside the rocker shaft and the outer contour when bundled are substantially the same as the cross-sectional contour of the axial hole, and when bundled, each of the individual holes so that there is a gap along the axial direction at the center. A plurality of inner pipe members formed with
An oil passage structure for a rocker shaft, wherein a fixing member for fixing the inner pipe member to the axial hole is press-fitted into the gap after the plurality of inner pipe members are bundled and inserted into the axial hole. . 3. The rocker shaft oil passage structure according to claim 1, wherein a surface of the inner pipe member facing the fixing member forming the gap is an arcuate concave surface. 4. Provided at the opening end of the axial hole is a cover member having a convex portion that fits in the axial end portion of the plurality of inner tube members, and the protruding end of the convex portion into the inner tube member is fixed The rocker shaft oil passage structure according to any one of claims 1 to 3, wherein the oil passage structure is positioned inward of the axial hole from an end of the member on the lid member side.

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