JP2018145836A - Rocker arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a rocker arm while restricting generation of a twisting force.SOLUTION: A power point side arm 44L, 44R of a rocker arm 10L, 10R is formed offset to one side along the axial direction of an exhaust rocker shaft 32 in an oscillation pivot 42L, 42R and is composed of a pair of arms 48L and 48R extending perpendicularly in the axial direction from the oscillation pivot 42L, 42R. A roller 30L, 30R is supported between the pair of arms 48L and 48R. An action point side arm 46L, 46R is formed offset to the other side along the axial direction in the oscillation pivot 42L, 42R and is composed of one arm extending perpendicularly in the axial direction from the oscillation pivot 42L, 42R.SELECTED DRAWING: Figure 2

Description

  The present invention includes a swing pivot supported by a rocker shaft, a power point side arm that supports a roller that extends from the swing pivot and contacts a cam, a valve that extends from the swing pivot and The present invention relates to a rocker arm including an action point side arm to be pressed.

  For example, in Patent Document 1, in order to reduce the weight of the rocker arm, the working point side arm that presses the valve extends from the central portion of the swing pivot supported by the rocker shaft, and the swing pivot supports. A roller-type rocker arm is disclosed in which a force point side arm extends from a position offset in the axial direction of the rocker shaft, and a roller that contacts the cam is cantilevered by the force point side arm.

  Further, in Patent Document 2, a pair of arms constituting a power point side arm extends from the swing pivot part to support the roller, and the force point side arm extends in an oblique direction from the central portion of the swing pivot part. A rocker arm that presses the valve is disclosed.

JP 2001-73722 A JP2013-209893A

  In Patent Document 1, since the roller is cantilevered, a torsional force is generated in the force point side arm, which may act on the rocker shaft.

  In Patent Document 2, since the roller is supported by the pair of arms, it is possible to suppress the generation of the twisting force in the power point side arm. However, since the action point side arm extends in an oblique direction, a torsional force is generated in the action point side arm, which may act on the rocker shaft.

  Then, an object of this invention is to provide the rocker arm which can aim at weight reduction, suppressing generation | occurrence | production of twisting force.

  The rocker arm (10L, 10R) according to the present invention includes a swinging pivot (42L, 42R) supported by the rocker shaft (32), a cam extending from the swinging pivot (42L, 42R) and a cam ( 26L, 26R), and the force point side arms (44L, 44R) that support the rollers (30L, 30R) that contact the rollers (26L, 26R), and extend from the swing pivots (42L, 42R) and press the valves (34L, 34R). It has an action point side arm (46L, 46R) and has the following features.

  The first feature; the force point side arms (44L, 44R) are formed offset to one side along the axial direction of the rocker shaft (32) in the swinging pivot support portions (42L, 42R), It consists of a pair of arms (48L, 48R) extending perpendicularly to the axial direction from the swinging pivot (42L, 42R). In this case, the rollers (30L, 30R) are supported between the pair of arms (48L, 48R). Further, the action point side arms (46L, 46R) are formed offset to the other side along the axial direction of the swing pivot portions (42L, 42R), and the swing pivot portions (42L, 42R, 42R, 42R). 42R) and one arm extending perpendicular to the axial direction.

  2nd characteristic; The said rocker arm (10L, 10R) sees the center of the said rocker axis | shaft (32) seeing from the said axial direction, and the said power point side arm (44L, 44R) which supports the said roller (30L, 30R). ) And the tip of the action point side arm (46L, 46R) that presses the valve (34L, 34R). Further, portions (54L, 54R) of the force point side arms (44L, 44R) facing the action point side arms (46L, 46R) are connected to the force point side arms (44L) from the swinging pivotal support portions (42L, 42R). 44R) is formed in an arc shape over the tip portion.

  Third feature: When viewed from the axial direction, the point (56L, 56R) opposite to the arcuate part (54L, 54R) of the force point side arm (44L, 44R) is the action point side arm. It is depressed toward (46L, 46R).

  4th characteristic; seeing from the said axial direction, between the said force point side arm (44L, 44R) and the said action point side arm (46L, 46R), it is dented toward the said rocker axis | shaft (32). One recess (58L, 58R) is formed.

  Fifth feature; the force point side arm (44L, 44R) and the action point side arm (46L, 46R) are separated from the swing pivot (42L, 42R) so as not to overlap each other along the axial direction. It extends perpendicular to the axial direction.

  6th characteristic; The said operation | use point side arm (46L, 46R) is formed with the 2nd recessed part (60L, 60R, 61L, 61R) recessed in the said axial direction.

  7th characteristic; The location which opposes the said valves (34L, 34R) in the said action | operation point side arm (46L, 46R) is formed as a thick part (62L, 62R) wide in the said axial direction.

  According to the first feature of the present invention, all the arms extending from the swinging pivot portion extend perpendicular to the axial direction of the rocker shaft. The roller is supported by a pair of arms. Thereby, generation | occurrence | production of the twisting force in each arm can be suppressed, and this twisting force can prevent acting on a rocking | fluctuation pivot part and a rocker shaft. In particular, since the rocker shaft rotates at a high speed, the rocker arm can be suitably disposed in the internal combustion engine. Further, by suppressing the generation of the twisting force, the action point side arm and the force point side arm can be formed thin. Thus, according to the first feature, it is possible to reduce the weight of the rocker arm while suppressing the generation of twisting force.

  According to the second feature of the present invention, among the rocker arms formed in a triangular shape when viewed from the axial direction, the portion of the force point side arm facing the action point side arm is formed in an arc shape. As a result, the force point side arm is smoothly connected to the swing support part and the action point side arm in an arc shape, and thus the weight of the rocker arm can be reduced while dispersing the stress generated in the force point side arm. .

  According to the third feature of the present invention, the portion on the opposite side to the arc-shaped portion on the force point side arm when viewed from the axial direction is recessed toward the action point side arm and is thinned, whereby the rocker The arm can be further reduced in weight.

  According to the fourth feature of the present invention, the lighter rocker arm can be further reduced in weight by forming the first recess between the force point side arm and the action point side arm.

  According to the fifth aspect of the present invention, the force point side arm and the action point side arm extend perpendicularly to the axial direction from the swinging pivot so that they do not overlap each other along the axial direction. The supporting portion and the portion that presses the valve are separated. Thereby, it is possible to avoid the force acting on the roller being directly transmitted to the valve. As a result, the occurrence of buckling in the rocker arm can be prevented.

  According to the sixth aspect of the present invention, the rocker arm can be further reduced in weight by forming the second recess in the working point side arm and removing the thickness.

  According to the seventh feature of the present invention, since the portion of the working point side arm facing the valve is formed as a thick portion, even when the working point side arm is formed thin, the machine of the working point side arm It is possible to reliably press the valve while securing the appropriate strength.

1 is a partial perspective view of a cylinder head of an internal combustion engine in which a rocker arm according to an embodiment is provided. It is a top view of the rocker arm of FIG. It is a left view of the rocker arm of FIG. It is a right view of the rocker arm of FIG. It is a partial perspective view of a cylinder head of an internal combustion engine provided with a rocker arm of a comparative example.

  The rocker arm according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[Schematic configuration of internal combustion engine 12]
FIG. 1 is a partial perspective view of a cylinder head 14 constituting an internal combustion engine 12 in which rocker arms 10L and 10R according to the present embodiment are disposed. The internal combustion engine 12 is an engine of a vehicle such as a motorcycle, for example, and FIG. 1 illustrates a state viewed from above with the head cover removed from the cylinder head 14. In FIG. 1, for ease of explanation, a partial configuration in the cylinder head 14 is simplified or broken. Further, since each part of the internal combustion engine 12 other than the cylinder head 14 has a configuration substantially similar to that of the conventional internal combustion engine, detailed description thereof is omitted. Furthermore, in the description of the present embodiment, the front-rear direction, the left-right direction, and the up-down direction will be described in accordance with the direction viewed from a passenger seated in a driver's seat of a vehicle (not shown).

  A cam shaft 16 extends in the left-right direction at the center of the cylinder head 14. The left and right sides of the camshaft 16 are rotatably supported by camshaft support portions 20L and 20R having ball bearings 18L and 18R. A cam sprocket 22 is attached to the left end of the camshaft 16, and a cam chain 24 that transmits rotation of a crankshaft (not shown) to the camshaft 16 is hung on the cam sprocket 22.

  In the camshaft 16, two exhaust cams 26L and 26R and two intake cams 28L and 28R are attached between the ball bearings 18L and 18R. In this case, two exhaust cams 26 </ b> L and 26 </ b> R are provided on the left and right at the central portion of the camshaft 16. A left intake cam 28L is provided between the left exhaust cam 26L and the left ball bearing 18L in the camshaft 16. On the other hand, a right intake cam 28R is provided between the right exhaust cam 26R and the right ball bearing 18R in the camshaft 16.

  The left exhaust cam 26L is in contact with the roller 30L supported by the rocker arm 10L according to the present embodiment. On the other hand, the roller 30R supported by the rocker arm 10R according to the present embodiment is in contact with the right exhaust cam 26R. The left and right rocker arms 10L and 10R are respectively disposed in front of the camshaft 16 and supported by an exhaust rocker shaft 32 (rocker shaft) extending left and right. In this case, the left and right rocker arms 10L and 10R are exhaust rocker arms, each having one end side (rear end side) pivotally supporting the rollers 30L and 30R and the other end side (front end side) disposed forward. This is a roller rocker arm that can press the left and right exhaust valves 34L, 34R (valves). A cylindrical guide member 36 is provided between the left and right exhaust valves 34L and 34R to guide insertion of a spark plug plug cap (not shown).

  On the other hand, intake rocker arms 38L and 38R are in contact with the left and right intake cams 28L and 28R. The intake rocker arms 38L and 38R are disposed behind the camshaft 16 and are supported by an intake rocker shaft 40 extending left and right. In this case, the left and right intake rocker arms 38L, 38R can respectively contact one end side (front end side) with the intake cams 28L, 28R and the other end side (rear end side) can press left and right intake valves (not shown). is there.

[Configuration of Rocker Arms 10L, 10R]
Next, the configuration of the rocker arms 10L and 10R according to the present embodiment will be described with reference to FIGS.

  The rocker arms 10L and 10R include substantially cylindrical swinging support portions 42L and 42R that are supported by the exhaust rocker shaft 32, respectively. On the swing pivot portions 42L and 42R, force point side arms 44L and 44R that support the rollers 30L and 30R extend rearward, and action point side arms 46L and 46R that press the exhaust valves 34L and 34R forward. It is extended. 2 to 4 representatively show the right rocker arm 10R, but the right rocker arm 10R and the left rocker arm 10L are symmetrical with respect to the center of the cylinder head 14. Note that it has the shape

  Here, the right rocker arm 10R will be described. In the rocker arm 10R, the force point side arm 44R is, as shown in FIG. 2, one side along the axial direction (left-right direction) of the exhaust rocker shaft 32 in the swing pivot portion 42R, specifically, the swing pivot portion. It is formed on the left side of 42R and offset to the center side of the cylinder head 14 (see FIG. 1). The power point side arm 44R includes a pair of arms 48R extending perpendicularly to the exhaust rocker shaft 32 (in the axial direction thereof) from the swing pivot support portion 42R.

  A through hole 50R is formed at the tip of each arm 48R. A shaft 52R extending through the center of the roller 30R and extending in the left-right direction is inserted into each through-hole 50R. Thus, the roller 30R is pivotally supported between the pair of arms 48R. In this case, the roller 30R is securely supported between the pair of arms 48R by caulking both ends of the shaft 52R.

  On the other hand, the action point side arm 46R is on the other side of the swing pivot portion 42R along the axial direction (left-right direction) of the exhaust rocker shaft 32, specifically, on the right side of the swing pivot portion 42R and the cylinder head. 14 is composed of one arm formed offset to the outside.

  That is, the force point side arm 44R and the action point side arm 46R extend perpendicularly to the axial direction from the swinging pivotal support portion 42R so as not to overlap each other along the axial direction.

  Here, the shape of the rocker arm 10R will be described in more detail. As shown in FIGS. 3 and 4, the rocker arm 10 </ b> R has a center of the exhaust rocker shaft 32 and a force point side arm 44 </ b> R (a pair of arms supporting the roller 30 </ b> R) when viewed from the axial direction of the exhaust rocker shaft 32. 48R) and the tip of the working point side arm 46R that presses the exhaust valve 34R are formed in a triangular shape. In this case, in the force point side arm 44R (each arm 48R), the portion facing the action point side arm 46R is an arcuate portion 54R formed in an arc shape from the swinging pivot support portion 42R to the tip end portion of the force point side arm 44R. It is said that.

  Further, when viewed from the axial direction, a portion of the force point side arm 44R (each arm 48R) opposite to the arcuate portion 54R, that is, a portion facing the exhaust cam 26R is directed to the action point side arm 46R. It is set as the hollow part 56R which became hollow toward. Therefore, the force point side arm 44R (each arm 48R) is formed in a curved shape that curves gently as a whole when viewed from the axial direction.

  Further, when viewed from the axial direction, a first recess 58R that is recessed toward the exhaust rocker shaft 32 and the swinging pivot support portion 42R is formed between the force point side arm 44R and the action point side arm 46R. Yes.

  Further, as shown in FIGS. 2 to 4, second recesses 60 </ b> R and 61 </ b> R that are recessed along the axial direction are respectively formed on the left and right sides of the action point side arm 46 </ b> R. In this case, the second recesses 60R and 61R are formed symmetrically in the action point side arm 46R. Further, by forming the second recesses 60R and 61R, a portion (lower portion) facing the exhaust valve 34R in the working point side arm 46R is arranged in the axial direction as shown in FIGS. It is formed as a wide thick portion 62R.

  On the other hand, the left rocker arm 10L has a symmetrical shape with respect to the right rocker arm 10R as described above. Therefore, in the above description, if the word “right” is replaced with “left”, the word “left” is replaced with “right”, and the reference symbol “R” is replaced with “L”, the left locker This is a description of the arm 10L. For example, in the left rocker arm 10L, the force point side arm 44L is formed offset to one side along the axial direction of the swing pivot portion 42L (the right side of the swing pivot portion 42L, the center side of the cylinder head 14). On the other hand, the action point side arm 46L is formed offset to the other side of the swing pivot part 42L along the axial direction (left side of the swing pivot part 42L, outside the cylinder head 14). Therefore, a detailed description of the left rocker arm 10L is omitted.

[Effect of this embodiment]
Next, effects of the rocker arms 10L and 10R according to the present embodiment will be described. FIG. 5 illustrates the case where the rocker arms 70L and 70R of the comparative example are arranged on the cylinder head 14 of the internal combustion engine 12. In addition, about the same structure as FIG. 1, the same referential mark is attached | subjected and detailed description is abbreviate | omitted.

  In the comparative example, a pair of arms 48L and 48R of the force point side arms 44L and 44R extend from the central portions of the swinging pivot support portions 42L and 42R of the rocker arms 70L and 70R, and support the rollers 30L and 30R. Further, the action point side arms 46L and 46R extend obliquely forward from the central portions of the swinging pivot support portions 42L and 42R of the rocker arms 70L and 70R to press the exhaust valves 34L and 34R.

  In this case, since the rollers 30L and 30R are respectively supported by the pair of arms 48L and 48R, it is possible to suppress the generation of a twisting force in the force point side arms 44L and 44R. However, since the action point side arms 46L and 46R extend in an oblique direction, a torsional force is generated in the action point side arms 46L and 46R, and the exhaust rocker shaft 32 is applied to the exhaust rocker shaft 32 via the swinging pivotal support portions 42L and 42R. Twisting force may be applied. Further, since the force point side arms 44L, 44R and the action point side arms 46L, 46R extend from the central part of the swinging pivotal support portions 42L, 42R, the force acting on the rollers 30L, 30R (exhaust cams 26L, 26R). Force) is directly transmitted to the exhaust valves 34L and 34R via the force point side arms 44L and 44R and the action point side arms 46L and 46R.

  On the other hand, in the rocker arms 10L and 10R according to the present embodiment, as shown in FIGS. 1 to 4, all the arms (power point side arms 44L and 44R extending from the swinging pivot support portions 42L and 42R are configured. A pair of arms 48L and 48R and action point side arms 46L and 46R) extend perpendicular to the axial direction of the exhaust rocker shaft 32. The rollers 30L and 30R are supported by a pair of arms 48L and 48R.

  Thereby, generation | occurrence | production of the twisting force in each arm can be suppressed, and it can prevent that this twisting force acts on rocking | fluctuation pivot support part 42L, 42R and the exhaust rocker shaft 32. FIG. In particular, since the exhaust rocker shaft 32 has a high rotation speed, the rocker arms 10L and 10R can be suitably disposed in the internal combustion engine 12. Further, by suppressing the generation of the twisting force, the force point side arms 44L and 44R and the action point side arms 46L and 46R can be formed thin. Thus, according to the present embodiment, it is possible to reduce the weight of the rocker arms 10L and 10R while suppressing the generation of twisting force.

  Further, of the rocker arms 10L and 10R formed in a triangular shape when viewed from the axial direction, portions facing the action point side arms 46L and 46R in the force point side arms 44L and 44R are formed as arcuate portions 54L and 54R. ing. As a result, the force point side arms 44L and 44R are smoothly connected in an arc shape with the swinging pivot support portions 42L and 42R and the action point side arms 46L and 46R. As a result, it is possible to reduce the weight of the rocker arms 10L and 10R while dispersing the stress generated in the force point side arms 44L and 44R.

  Furthermore, the hollow part 56L which hollowed out the location on the opposite side to the circular arc-shaped parts 54L and 54R in the force point side arms 44L and 44R when viewed from the axial direction toward the action point side arms 46L and 46R, By setting it to 56R, the rocker arms 10L and 10R can be further reduced in weight.

  Furthermore, by forming the first recesses 58L and 58R between the force point side arms 44L and 44R and the action point side arms 46L and 46R, the rocker arms 10L and 10R can be further reduced in weight. be able to.

  Further, since the force point side arms 44L, 44R and the action point side arms 46L, 46R extend perpendicularly to the axial direction from the swinging support portions 42L, 42R so as not to overlap each other along the axial direction, A portion that supports the rollers 30L and 30R and a portion that presses the exhaust valves 34L and 34R are separated. Thereby, it is possible to avoid the force acting on the rollers 30L and 30R being directly transmitted to the exhaust valves 34L and 34R. As a result, the occurrence of buckling can be prevented.

  Furthermore, by forming the second recesses 60L, 60R, 61L, 61R in the action point side arms 46L, 46R and removing the thickness, the rocker arms 10L, 10R can be further reduced in weight.

  Furthermore, since the portions of the action point side arms 46L and 46R that face the exhaust valves 34L and 34R are formed as thick portions 62L and 62R, even if the action point side arms 46L and 46R are formed thin, the action is performed. The exhaust valves 34L and 34R can be reliably pressed while the mechanical strength of the point side arms 46L and 46R is secured.

  As mentioned above, although this invention was demonstrated using suitable embodiment, the technical scope of this invention is not limited to the description range of said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. It is apparent from the description of the scope of claims that the embodiments added with such changes or improvements can also be included in the technical scope of the present invention. In addition, the reference numerals in parentheses described in the claims are appended to the reference numerals in the accompanying drawings for easy understanding of the present invention. It should not be construed as limited.

10L, 10R, 70L, 70R ... Rocker arm 12 ... Internal combustion engine 14 ... Cylinder head 16 ... Camshaft 18L, 18R ... Ball bearing 20L, 20R ... Camshaft support 22 ... Cam sprocket 24 ... Cam chain 26L, 26R ... Exhaust cam 28L, 28R ... intake cam 30L, 30R ... roller 32 ... exhaust rocker shaft (rocker shaft)
34L, 34R ... Exhaust valves (valves) 36 ... Guide members 38L, 38R ... Intake rocker arms 40 ... Intake rocker shafts 42L, 42R ... Swing pivots 44L, 44R ... Power point side arms 46L, 46R ... Action point side arms 48L, 48R ... arms 50L, 50R ... through holes 52L, 52R ... shafts 54L, 54R ... arc-shaped portions 56L, 56R ... dents 58L, 58R ... first recesses 60L, 60R, 61L, 61R ... second recesses 62L, 62R ... meat Thick part

Claims (7)

Swing pivots (42L, 42R) supported by the rocker shaft (32), and rollers (30L, 30R) extending from the swing pivots (42L, 42R) and contacting the cams (26L, 26R) A rocker provided with a force point side arm (44L, 44R) for supporting the pressure point and an action point side arm (46L, 46R) extending from the swinging pivotal support (42L, 42R) and pressing the valve (34L, 34R) In the arms (10L, 10R)
The force point side arms (44L, 44R) are formed offset to one side of the rocking pivot (42L, 42R) along the axial direction of the rocker shaft (32), and the rocking pivot (42L) 42R) and a pair of arms (48L, 48R) extending perpendicular to the axial direction,
The rollers (30L, 30R) are supported between the pair of arms (48L, 48R),
The action point side arms (46L, 46R) are formed to be offset to the other side along the axial direction of the swing pivot portions (42L, 42R), and are formed from the swing pivot portions (42L, 42R). A rocker arm (10L, 10R) comprising one arm extending perpendicular to the axial direction. The rocker arm (10L, 10R) according to claim 1,
The rocker arm (10L, 10R) includes a center of the rocker shaft (32) and a tip portion of the force point side arm (44L, 44R) that supports the roller (30L, 30R) when viewed from the axial direction. , Formed in a triangular shape having the apex at the tip of the working point side arm (46L, 46R) that presses the valve (34L, 34R),
The locations (54L, 54R) of the force point side arms (44L, 44R) facing the action point side arms (46L, 46R) are connected to the force point side arms (44L, 44R) from the swing pivotal support portions (42L, 42R). The rocker arm (10L, 10R) is characterized by being formed in an arc shape over the tip of the head. The rocker arm (10L, 10R) according to claim 2,
When viewed from the axial direction, the points (56L, 56R) on the opposite side of the arc-shaped points (54L, 54R) in the force point side arms (44L, 44R) are the action point side arms (46L, 46R). Rocker arms (10L, 10R), which are recessed toward the surface. In the rocker arm (10L, 10R) according to claim 2 or 3,
A first recess (58L, recessed toward the rocker shaft (32) between the force point side arm (44L, 44R) and the action point side arm (46L, 46R) when viewed from the axial direction. 58R) is formed, Rocker arm (10L, 10R). In the rocker arm (10L, 10R) according to any one of claims 1 to 4,
The force point side arm (44L, 44R) and the action point side arm (46L, 46R) are orthogonal to the axial direction from the swinging pivot (42L, 42R) so as not to overlap each other along the axial direction. Rocker arms (10L, 10R) characterized by extending. In the rocker arm (10L, 10R) according to any one of claims 1 to 5,
A rocker arm (10L, 10R) characterized in that a second recess (60L, 60R, 61L, 61R) recessed in the axial direction is formed in the action point side arm (46L, 46R). In the rocker arm (10L, 10R) according to any one of claims 1 to 6,
The rocker arm characterized in that a portion of the action point side arm (46L, 46R) facing the valve (34L, 34R) is formed as a thick portion (62L, 62R) that is wide in the axial direction. (10L, 10R).

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