JP2009091968A - Variable valve train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve train having improved response and suppressed abnormal noises in change-over by smoothly supplying hydraulic pressure via a short oil path. <P>SOLUTION: In the variable valve train 9, a rocker shaft 4 is supported by a lash adjuster 30, a rocker arm 20 is rockably journaled at its bearing portions 21a, 26a to the rocker shaft 4, and a hydraulic change-over mechanism 40 is provided on the rocker arm 20. An oil supply port 32 for the rocker shaft 4 is formed in the lash adjuster 30, a first oil path 61 is formed in the rocker shaft 4 communicatively passing from the oil supply port 32 crosswisely through the rocker shaft 4 without extending in the axial direction, a cover portion 27 is formed on the rocker arm 20 separately from the bearing portion 26a to cover an opening 62 of the first oil path in the surface of the rocker shaft 4 and its periphery, and a second oil path 65 is formed in the cover portion 27 communicatively extending from the opening 62 of the first oil path to the change-over mechanism 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable valve mechanism that switches the opening / closing amount of a valve in an internal combustion engine by hydraulic pressure.

  In this type of variable valve mechanism, a rocker arm formed by pivotally mounting an input member that contacts the rotating cam and an output member that contacts the valve on a rocker shaft, and the input member and the output member are relatively displaced. There is a configuration that includes a switching mechanism that performs switching by hydraulic pressure between a connection state in which the connection is impossible and a connection release state in which the connection is released, and changes the opening / closing amount of the valve by adjusting the hydraulic pressure.

  For example, in Patent Document 1, as in Conventional Example 1 shown in FIG. 5, a connecting pin 127 provided so as to be displaceable between a position straddling between the input member 123 and the output member 125 and a position not straddling. And a switching mechanism 126 including a hydraulic chamber 128 provided inside the base end portion of the rocker arm for hydraulically driving the connecting pin 127, and a variable valve that supplies hydraulic pressure from the lash adjuster 130 to the hydraulic chamber 128 The mechanism is shown. In this variable valve mechanism, the hydraulic chamber 128 of the switching mechanism is provided so as to directly communicate with the supply port of the lash adjuster 130 that is a hydraulic pressure supply source without providing an oil passage.

  However, according to the variable valve mechanism of the conventional example 1, the positional relationship between the switching mechanism and the lash adjuster and the structure are greatly limited.

  Therefore, as a case where the hydraulic chamber of the switching mechanism and the hydraulic supply source such as the lash adjuster are provided at positions separated from each other, a variable valve mechanism that forms an oil passage that connects the two is known.

  For example, in Patent Document 2, as in Conventional Example 2 shown in FIG. 6, an oil passage 136 that is long in the axial direction is formed inside the rocker shaft 134 and communicates from the oil passage 136 to the hydraulic chamber 137. A variable valve mechanism 133 that supplies hydraulic pressure to the hydraulic chamber 137 of the switching mechanism through the provided oil passage 138 is shown.

However, when the hydraulic pressure is supplied through an oil passage that is formed long by extending in the axial direction of the rocker shaft as in the conventional example 2, not only the response at the time of switching is deteriorated but also noise is generated. Also become.
US Patent Application Publication No. 2004/0074459 JP 2006-299916 A

  Accordingly, an object of the present invention is to provide a variable valve mechanism that improves the response at the time of switching and suppresses the generation of abnormal noise and the like by smoothly supplying hydraulic pressure through a short oil passage. .

  In order to solve the above problems, the variable valve mechanism of the present invention supports a rocker shaft by a lash adjuster, and pivotally mounts a rocker arm on the rocker shaft so that the rocker arm can swing at a bearing portion thereof. In the provided variable valve mechanism, an oil supply port to the rocker shaft is formed in the lash adjuster, and the rocker shaft communicates with the rocker shaft from the oil supply port and penetrates the rocker shaft in a transverse manner without extending in the axial direction. A first oil passage is formed, and a cover portion is formed separately from the bearing portion and covers the opening of the first oil passage on the rocker shaft surface and the periphery thereof on the rocker arm, and communicates with the cover portion from the opening of the first oil passage. Thus, a second oil passage extending to the switching mechanism is formed.

  Here, the switching mechanism is not particularly limited, and a switching mechanism that switches between a driving state in which the valve is driven according to the rotation of the rotating cam and a driving stop state in which the driving is completely stopped, or the rotating cam. The valve can be switched between a high lift state in which the valve is opened and closed with a relatively large lift amount and a low lift state in which the valve is opened and closed with a relatively small lift amount according to the rotation.

  The first oil passage includes one bent in the middle, but a preferable embodiment of the first oil passage can be exemplified by one formed through the diameter of the rocker shaft.

  Although it does not specifically limit as a 2nd oil path, The aspect currently formed substantially linearly from the opening of the 1st oil path to the switching mechanism can be illustrated as a preferable thing.

  Although it does not specifically limit as a lash adjuster, The aspect provided so that it may be located in the direction orthogonal to the axial direction of a rocker shaft from the hydraulic chamber of a switching mechanism can be illustrated as a preferable thing.

As a most preferable aspect, in the variable valve mechanism, the lash adjuster is provided in a direction perpendicular to the axial direction of the rocker shaft from the hydraulic chamber, the first oil passage is formed through the diameter of the rocker shaft, An example in which the two oil passages are formed substantially linearly from the opening of the first oil passage to the switching mechanism can be exemplified.
According to this aspect, the hydraulic pressure can be supplied from the supply port of the lash adjuster to the hydraulic chamber of the switching mechanism through the shortest path. Moreover, since it is not necessary to bend and form an oil path except for the connection part of a 1st oil path and a 2nd oil path, the structure of an oil path can be simplified.

  The communication port of the second oil passage that communicates with the opening of the first oil passage is not particularly limited, but corresponds to the range of rocking so that the cover portion always communicates with the opening even if the cover rocks with the rocker arm. An embodiment that is long and open can be illustrated as a preferable example.

  Although it does not specifically limit as a lash adjuster, The aspect formed in the shape which fits the periphery of a fuel filler opening | mouth to a rocker shaft can be illustrated as a preferable thing.

The variable valve mechanism according to the first to third aspects of the present invention improves the response at the time of switching and suppresses the generation of abnormal noise, etc., by smoothly supplying the hydraulic pressure through a short path oil passage. it can.
The variable valve mechanism according to the fourth aspect of the invention can always adjust the hydraulic pressure regardless of the rocker arm swinging.
The variable valve mechanism according to the fifth aspect of the present invention can be communicated with the first oil passage so that oil does not leak from the oil supply port of the lash adjuster. Further, the rocker shaft can be supported more stably by fitting the lash adjuster and the rocker shaft.

  The variable valve mechanism 9 supports the rocker shaft 4 by a lash adjuster 30, and a rocker arm 20 is pivotally mounted on the rocker shaft 4 so as to be swingable at its bearing portions 21a and 26a, and a hydraulic switching mechanism 40 is provided on the rocker arm 20. It is a thing. The lash adjuster 30 is formed with an oil supply port 32 to the rocker shaft 4, and communicates from the oil supply port 32 to the rocker shaft 4 to penetrate the rocker shaft 4 in a transverse manner without extending in the axial direction. 61, a first oil passage opening 62 on the surface of the rocker shaft 4 and a cover portion 27 covering the periphery thereof are formed separately from the bearing portion 26a in the rocker arm 20, and the first oil passage opening is formed in the cover portion 27. A second oil passage 65 communicating from 62 and extending to the switching mechanism 40 is formed.

The lash adjuster 30 is provided in a direction perpendicular to the axial direction of the rocker shaft 4 from the hydraulic chamber 53, and is formed in a shape that fits the peripheral portion of the oil filler port 32 to the rocker shaft. The first oil passage 61 is formed through the diameter of the rocker shaft 4. The second oil passage 65 is formed substantially linearly from the opening 62 of the first oil passage to the switching mechanism 40.
Further, the communication port 28 of the second oil passage that communicates with the opening 62 of the first oil passage corresponds to the range of rocking so that the cover portion 27 always communicates with the opening 62 even if the cover 27 swings together with the rocker arm 20. And it is a long opening.

  The variable valve mechanism 9 shown in FIGS. 1 to 4 of the present embodiment is a mechanism that switches the opening / closing amount of the valve 7 by hydraulic pressure in accordance with the operating state of the internal combustion engine. In this embodiment, the variable valve mechanism 9 is provided only for half of the cylinders 5 (not shown), and each variable valve mechanism 9 is provided for each cylinder 5. Each of the two intake valves 7 is driven. The variable valve mechanism 9 is interposed between a rotary cam 10 that rotates in accordance with the rotation of the internal combustion engine, a valve spring 15 that biases the valve 7 in a closing direction, and a rotary cam 10 and the valve 7 that can swing. The rocker arm 20 and a switching mechanism 40 for switching the state of the rocker arm 20 are configured to switch between a driving state in which the valve 7 is driven according to the rotation of the rotary cam 10 and a driving stop state in which the driving is stopped. The switching is performed with.

  The rotary cam 10 is formed on a camshaft 10x that is rotationally driven as the internal combustion engine operates, and includes a base circle portion 11 that is a basic portion and a cam nose 12 that protrudes from the base circle portion 11. Has been. The rotating cam 10 is disposed above the rocker arm 20, and a cam surface 10 s that presses the input roller 23 of the rocker arm 20 is formed on the outer peripheral surface of the rotating cam 10. In FIG. 1, for the sake of convenience, the rotating cam 10 and the camshaft 10x are indicated by a two-point difference line.

The rocker arm 20 is a two-valve integrated arm that drives the two valves 7 at the same time, and includes an input member 21 that contacts the rotating cam 10 and an output member 26 that contacts the valve 7. Further, the base ends of the input member and the output member 26 are swingably supported by the rocker shaft 4 at the bearing portions 21a and 26a.
The input member 21 is an inner arm provided inside the output member 26, and a bearing portion 21 a through which the rocker shaft 4 is inserted is formed at the base end thereof. An input roller 23 is attached to the distal end of the input roller 23 so as to be rotatably in contact with the rotary cam 10. A lost motion spring 35 is attached to the input member 21 and biases the input member 21 toward the rotary cam 10.

  The output member 26 is an outer arm that is provided on both outer sides of the input member 21 and is longer on the distal end side than the input member 21, and a bearing portion 26 a through which the rocker shaft 4 is inserted is formed at the base end. . A curved output surface 26b that abuts on the stem end 7e of the valve 7 is formed at the tip. Further, a cover portion 27 is formed on one output member 26 separately from the bearing portion 26a.

  The cover portion 27 is provided on the output member 26 so as to be located on the side of the bearing portion 26a, and covers an opening of a first oil passage 61 (described later) on the surface of the rocker shaft 4 and its periphery. Specifically, the cover portion 27 is a plate-like member having a thickness capable of forming the oil passage 60 therein, and is slidably in contact with the peripheral surface of the rocker shaft 4 at the tip thereof. This contact surface covers, for example, about one-half to one-third of the entire circumference of the rocker shaft 4. Further, a communication port 28 of the second oil passage 65 is formed on the contact surface so that the first oil passage 61 can communicate with the second oil passage 65.

The rocker shaft 4 is supported from below by a pair of lash adjusters 30 and 33 on both sides in the axial direction. The upper part of one of the two lash adjusters 33 is formed in a ring shape (see FIG. 3C), and the rocker shaft 4 is inserted through the ring portion 34. The other lash adjuster 30 is provided so as to be located in a direction orthogonal to the axial direction of the rocker shaft 4 from the hydraulic chamber 53, and is formed in the shape of a recess 31 that fits the peripheral portion of the oil filler port 32 to the peripheral surface of the rocker shaft. (See FIGS. 3A and 3B). An oil supply port 32 opened upward for supplying hydraulic pressure to the rocker shaft 4 is formed on the contact surface.
Here, polishing a ring-shaped one is difficult because the shape is easily distorted. In addition, the lash adjuster formed in the concave shape has an advantage that the cold forgeability is high and centerless polishing is possible as compared with the case where the ring shape is formed. Therefore, compared with the case where both are formed in a ring shape, the productivity is improved by forming one in a concave shape.

  The switching mechanism 40 is a mechanism for switching between a connection state in which the input member 21 and the output member 26 are connected to each other so that they cannot be displaced relative to each other, and a connection release state in which the connection is released. 26, connecting pins 46, 47 provided so as to be displaceable between a position straddling and a position not straddling 26, and a hydraulic chamber provided inside the rocker arm for hydraulically driving the connecting pins 46, 47 53 and an oil passage 60 for supplying hydraulic pressure to the hydraulic chamber 53.

The oil passage 60 communicates with the oil supply port 32 and passes through the rocker shaft 4 in the diameter direction thereof, and from the opening 62 of the first oil passage 61 formed in the cover portion 27. And a second oil passage 65 that communicates and extends to the switching mechanism 40.
The first oil passage 61 is formed so as to penetrate the rocker shaft 4 in a transverse manner without extending in the axial direction through the oil supply port 32. The lower opening of the first oil passage 61 communicates with the oil supply port 32 of the lash adjuster 30, and the upper opening 62 communicates with the second oil passage 65.
The second oil passage 65 is formed in a substantially linear shape toward the switching mechanism 40 while communicating from the opening 62 above the first oil passage 61 inside the cover portion 27 and the output member 26. At this time, since the lash adjuster 30 is located in a direction orthogonal to the axial direction of the rocker shaft 4 from the hydraulic chamber 53 of the switching mechanism 40, the length of the second oil passage 65 can be minimized.
Further, the communication port 28 of the second oil passage communicating with the opening 62 of the first oil passage corresponds to a swinging range so that the cover portion 27 always communicates with the opening even if the cover portion 27 swings together with the output member 26. It is formed to be long and open.

  The state of the variable valve mechanism 9 as described above will be described below separately for (1) when the internal combustion engine is rotating at a low speed and (2) when the internal combustion engine is rotating at a high speed.

(1) At the time of low speed rotation of the internal combustion engine At this time, as shown in FIG. 2A, when the hydraulic pressure in the hydraulic chamber 53 is increased, the two connecting pins 46, 47 is driven to expand the hydraulic chamber against the pressing force of the spring 56. The boundaries of the pins arranged in a straight line in the order of the closing pin 52, the first connecting pin 46, and the second connecting pin 47 coincide with the boundary between the arms. Therefore, the first connecting pin 46 and the second connecting pin 47 do not straddle each other between the holes, and are in a disconnected state, and the input member 21 and the output member 26 are relatively centered on the respective base end portions. It can be turned. At this time, the input member 21 swings independently of the output member 26 in accordance with the rotation of the rotary cam 10 as shown in FIG. For this reason, in this disconnected state, the valve 7 is in a drive stop state, and half of the cylinders 5 in which the variable valve mechanism 9 is installed are not inhaled, and only from the remaining half of the cylinders. The internal combustion engine is operated by the output.

(2) At High Speed Rotation of Internal Combustion Engine At this time, as shown in FIG. 2B, the hydraulic pressure in the hydraulic chamber 53 decreases, so that the two connecting pins 46 and 47 are pressed by the pressure of the spring 56 to Driven to narrow. At this time, each connection pin 46 and 47 is arranged at a position across the boundary between the arms, and is in a connected state. At this time, as shown in FIG. 4B, the rocker arm 20 is configured such that the input member 21 and the output member 26 swing integrally with the rotation of the rotary cam 10 around the respective base end portions. The valve 7 is pressed downward and driven by the output surface 26b at the front end portion of the valve 26. For this reason, in this connected state, intake is also performed to the cylinder 5 in which the variable valve mechanism 9 is installed, and the internal combustion engine is operated by the output from all the cylinders.

According to the variable valve mechanism according to the present embodiment, the following effects (a) to (f) can be obtained.
(A) Since the hydraulic pressure is supplied through the shortest path, the switching can be performed smoothly. Along with this, the occurrence of abnormal noise and the like can be suppressed.
(B) Since it is not necessary to bend the oil passage except for the connecting portion between the first oil passage and the second oil passage, the structure of the oil passage is simple and the path is short.
(C) The first oil passage 61 can be communicated with the lash adjuster 30 so that oil does not leak from the oil filler port 32.
(D) Since the lash adjuster 30 and the rocker shaft 4 are fitted, the rocker shaft 4 can be supported more stably.
(E) Regardless of the swinging of the output member 26, the opening 62 of the first oil passage is always in communication with the second oil passage, so that the hydraulic pressure can always be adjusted.
(F) Since the hydraulic chamber 53 is provided inside the output member 26, there is no need to separately provide a pin drive mechanism for driving the connecting pins 46 and 47 outside the rocker arm 20, and the structure of the switching mechanism 40 is simplified. Can be.

  In addition, this invention is not limited to the said Example, In the range which does not deviate from the meaning of invention, it can change suitably and can be actualized. For example, the contact portion with the rocker shaft 4 may be formed in the shape of the concave portion 31 that fits the peripheral surface of the rocker shaft 4 with respect to both the pair of lash adjusters 30 and 33.

It is a perspective view which shows the variable valve mechanism based on the Example of this invention. In the same Example, (a) is a plane sectional view which shows a mode when an input member and an output member are a connection cancellation | release state, (b) is a plane sectional view which shows a mode at the time of a connection state. The lash adjuster in the same embodiment, (a) is a sectional view showing the vicinity of the supply port when the output member does not swing, (b) is a sectional view showing the vicinity of the supply port when the output member is swung, (C) is sectional drawing which shows a ring part. In the same Example, (a) is a front view which shows the mode of valve drive when an input member and an output member are a connection cancellation | release state, (b) is a front view which shows the mode of valve drive when it is a connection state. It is sectional drawing which shows the prior art example 1. It is sectional drawing which shows the prior art example 2.

Explanation of symbols

4 Rocker shaft 9 Variable valve mechanism 20 Rocker arm 21a Bearing part 26a Bearing part 27 Cover part 28 Communication port 30 Rush adjuster 32 Oil supply port 40 Switching mechanism 53 Hydraulic chamber 56 Spring 60 Oil path 61 First oil path 62 Opening 65 Second oil Road

Claims (5)

In a variable valve mechanism that supports a rocker shaft by a lash adjuster, a rocker arm is pivotally attached to the rocker shaft at its bearing, and a rocker arm is provided with a hydraulic switching mechanism.
Forming an oil supply port to the rocker shaft in the lash adjuster, and forming a first oil passage that penetrates the rocker shaft in a transverse manner without extending in the axial direction by communicating with the rocker shaft from the oil supply port; A cover portion that covers the rocker arm and the opening of the first oil passage on the surface of the rocker shaft is formed separately from the bearing portion, and the cover portion communicates from the opening of the first oil passage and extends to the switching mechanism. A variable valve mechanism characterized by forming two oil passages.   The variable valve mechanism according to claim 1, wherein the first oil passage is formed so as to penetrate a diameter of the rocker shaft.   The variable valve mechanism according to claim 1 or 2, wherein the second oil passage is formed substantially linearly from the opening of the first oil passage to the switching mechanism.   The communication port of the second oil passage that communicates with the opening of the first oil passage has a long opening corresponding to the swinging range so that the cover portion always communicates with the opening even if the cover portion swings with the rocker arm. The variable valve mechanism according to claim 1, 2, or 3.   The variable valve mechanism according to claim 1, 2, 3, or 4, wherein the lash adjuster is formed in a shape in which a peripheral portion of the oil filler port is fitted to the rocker shaft.

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