CN1189644C

CN1189644C - Rocker arm

Info

Publication number: CN1189644C
Application number: CNB011338628A
Authority: CN
Inventors: 田中力; 山田范之; 山田真嗣; 中村弘; 小岛祯夫; 岩本纯一
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2000-12-21
Filing date: 2001-12-21
Publication date: 2005-02-16
Anticipated expiration: 2021-12-21
Also published as: JP2002188413A; JP3683807B2; TW494174B; CN1360136A

Abstract

A rocker arm (4) rockingly supported on a rocket shaft (3) has: a roller (11) rotatably supported on a roller shaft (9) provided to extend between a pair of supporting walls (8) formed at a cam facing portion (4a); spacers (12) provided so as to be held between axial ends of the roller and the supporting walls, respectively; and a rotation restriction means provided between the spacers and the supporting walls which comprises, for example, projections (13) provided on the spacers in such a manner as to extend radially outwardly and a recessed portion (15) for receiving therein in projections, whereby since the roller can be prevented from being brought into contact with the rocker arm, the rocker arm can be made difficult to wear. Moreover, since the spacers do not rotate together with the roller, wear can be suppressed that would otherwise result from the contact with the spacers.

Description

Rocking arm

Technical field

The present invention relates to a kind of rocking arm, this rocking arm constitutes the part of valve gear, especially relates to a kind of rocking arm with roller, and this roller is used for contacting with the cam rolling.

Background technique

In order to reduce the moment of the valve gear that loses owing to friction, a kind of effective ways are that roller be can be rotated to support on the Roller Shaft, this Roller Shaft be formed at rocking arm facing to a pair of abutment wall on the part of cam between extend, like this, this roller will roll with cam and contact.

On the other hand, in order to improve the response of this valve gear, a kind of effective ways are that rocking arm is made to reduce its weight by aluminum alloy.But, when roller is installed between the abutment wall that is used for supporting roller in the rocking arm of being made by aluminum alloy,, thereby cause the abutment wall wear problems because the higher roller termination of hardness ratio abutment wall contacts with this abutment wall.

In order to address this problem, JP-B-4-44803U discloses a kind of structure, and wherein, pad inserts between rocking arm and the roller, otherwise they will be in slidable contact with each other.

But, according to the disclosed technology of this model utility,, therefore worry when pad and this abutment wall sliding contact, will make the abutment wall wearing and tearing of this rocking arm because this pad rotates with roller when roller rotates.

Summary of the invention

The present invention be used for solving prior art intrinsic problem, main purpose of the present invention provides a kind of rocking arm, this rocking arm can further improve its wearability.

In order to realize this purpose, according to a first aspect of the invention, provide a kind of rocking arm that is supported on swingably on the pitman arm shaft, this rocking arm comprises: a roller, this roller is rotatably supported on the Roller Shaft of extending between a pair of abutment wall, and this abutment wall faces toward on the part of cam rocking arm; And pad, this pad lays respectively at described Roller Shaft to end portion and abutment wall part respect to one another place, and described rocking arm is characterised in that: the swiveling limitation mechanism that is used to limit the rotation of described pad is located between described pad and the described rocking arm; Described swiveling limitation mechanism comprises and is located on the described pad and the projection that extends radially outwardly and be formed in the described rocking arm and be used for holding therein the concave portions of described projection; Described concave portions is located at the select location place, and is not positioned at and makes on described pitman arm shaft axle center and the straight line that described Roller Shaft axle center links to each other.

According to this structure, contact with rocking arm because can prevent roller, therefore can make this rocking arm be difficult to wearing and tearing.And, because pad does not rotate with this roller, therefore, can be suppressed at the wearing and tearing of the rocking arm that causes under rotation pad and the situation that rocking arm contacts.

On pad, be provided with radially outer projection (13) according to the present invention, this projection (13) is stretched out from this pad, the concave portions (15) of holding projection is formed in the rocking arm and at a select location, on the straight line (A) that this position does not link to each other with the axle center of Roller Shaft in the axle center that makes pitman arm shaft, therefore, can prevent this pad rotation by this projection and this concave portions.

According to this structure, be formed at select location avoiding the thin part of rocking arm by making this concave portions, thereby suppress the reduction of this rocking arm rigidity.In addition, because need on this rocking arm, not provide thick especially part, this rocking arm is increased to form this concave portions.

According to a second aspect of the invention, provide the concave portions that is used to hold the radially outwardly directed projection on the pad in rocking arm, this concave portions is in the position of the outer surface that faces toward roller, and this roller is between this is to abutment wall.Like this, because rotary actuator can be provided in rocking arm, this rocking arm is increased.In addition, because concave portions also needn't be formed in the abutment wall, therefore can not reduce the supporting rigidity of Roller Shaft.

According to a third aspect of the invention we, with the curved section (14) of the contacted inner surfaces of concave portions on this projection.Therefore, contact, make the more difficult wearing and tearing of this rocking arm because rotary actuator carries out face with rocking arm.And, because the rigidity of rotary actuator is owing to this curved section increases, therefore can make this pad attenuation.

According to a forth aspect of the invention, this concave portions is in that side that does not face toward cam with respect to Roller Shaft of rocking arm.Therefore, because concave portions can be provided and need not provide special thick part in addition, therefore can make the more close cam of this rocking arm, thereby can make this valve gear chamber miniaturization and make the motor miniaturization in that side of rocking arm facing to cam.

Description of drawings

Fig. 1 is the side view that the critical piece of valve gear of the present invention has been adopted in expression;

Fig. 2 is the sectional view of the critical piece of expression rocking arm;

Fig. 3 is the partial sectional view along the line III-III among Fig. 2;

Fig. 4 is the perspective view of pad.

Embodiment

Introduce the present invention below with reference to the accompanying drawings.

Fig. 1 has schematically illustrated the structure that adopts valve gear of the present invention.This valve gear comprises a Rocker arm 4 and a suction valve 7.This Rocker arm 4 can be rotated to support on the pitman arm shaft 3, can swing during with the cam 2 of box lunch on being located at rotating cam axle 1.Suction valve 7 and is subjected to valve spring 6 bias voltages and cuts out usually in the cylinder head of motor.

Rocker arm 4 comprises: the part 4a facing to cam should be used for against this cam 2 facing to the part 4a of cam; One center hub part 4b, this center hub part 4b can be rotated to support on the pitman arm shaft 3; And the part 4c that faces toward valve, should be used for against the upper end of suction valve 7 facing to the part 4c of valve.Integral body forms this Rocker arm 4 by die casting by aluminum alloy., overcome the biasing force of valve spring 6 and open driving suction valve 7 so that when swinging when the rotation interlocking of Rocker arm 4 and camshaft 1, this biasing force is along the directive effect that valve cuts out.

Shown in Fig. 2 and 3, the part 4a bifurcated facing to cam of Rocker arm 4, Roller Shaft 9 press fits are contained in a pair of abutment wall 8 that is arranged in this furcation office, and are fixed on this on the abutment wall 8.Roller 11 with needle bearing 10 pivotally is contained on the core of this Roller Shaft 9.This roller 11 with the outer surface of cam 2 pressure that the H place, higher position that also is subjected to this rotating cam 2 when contact produces that rolls, so will reduce the moment of the valve gear that loses owing to rubbing.

A pair of pad 12 loose fits are installed on the Roller Shaft 9.The external diameter of this pad is less than the external diameter of roller 11, and thickness is less than determined spacing between each end of this needle bearing 10 and roller 11 and corresponding abutment wall 8 respectively.Should be known in that this pad 12 can be made by any materials that is enough to bear owing to the wearing and tearing that cause with needle bearing 10 and contacting of roller 11.

On the outer peripheral portion of pad 12, be formed with radially outer protruding 13.The opening end of this projection 13 forms arrow-shaped, and this sagittate angle is about 90 degree.Be formed with curved section 14 in projection 13 open end along surperficial rectangular direction, just with direction bending along the axis of Roller Shaft 9 with this pad 12.In addition, because this curved section 14 bends towards this inside to abutment wall 8 respectively,, rocking arm is increased just towards roller 11 those sides.

Concave portions 15 be formed at Rocker arm 4 with respect to this concerning the Roller Shaft 9 in the abutment wall 8 facing on that side of cam 2, and the select location place on the straight line that links to each other in the axle center that is not positioned at the axle center that makes pitman arm shaft 3 and Roller Shaft 9, the projection 13 of pad 12 is loaded in this concave portions 15 with form relatively closely.This concave portions 15 is recessed on from this internal surface respect to one another to abutment wall 8.The curved section 14 that forms on the protruding end of the projection 13 of pad 12 can be against the internal surface of this concave portions 15.In addition, this concave portions 15 especially is formed at will thickening to guarantee to have enough rigidity to bear that side of the squeezing action power that cam 2 applies of this rocking arm, especially, stress departs from the straight line B that is connecting camshaft 1 axle center and Roller Shaft 9 axle center with the corner part of concentrating in this concave portions 15.By adopting said structure, can form concave portions 15, can not increase simultaneously the distance between the axle center of pitman arm shaft 3 and Roller Shaft 9, and, because the rigidity that causes owing to the impact load of cam 2 reduces and owing to the rigidity facing to the part 4a place of cam that is formed with that concave portions 15 causes reduces all will be suppressed, so can not increase this Rocker arm 4.

As mentioned above, can prevent that pad 12 is around Roller Shaft 9 rotations.In addition, pad 12 is removably mounted on the abutment wall 8, and can pull down from this abutment wall 8 when needed.

In the valve gear that constitutes as mentioned above, when camshaft 1 began to be rotated motion, the roller 11 that contacts with the higher section H of cam 2 began rotation, bears pressure simultaneously.Then, rocking arm is owing to this pressure is swung, and is resisted against this and opens facing to the suction valve 7 on the part 4c of valve thereby make.

At this moment, even responsive to axial force is on roller 11 when the contact conditions of roller 11 and cam 2 changes, because the axial end surface of roller 11 respectively with pad 12 sliding contacts, therefore, although the hardness of abutment wall 8 is lower than roller 11, the internal surface of the abutment wall of being made by aluminum alloy 8 can be owing to the rotation of roller 11 is worn and torn yet.In addition, when needle bearing 10 with the rotation of roller 11 during circumferential movement, because the axial end of needle bearing 10 also contacts with this pad 12 respectively, therefore, although the hardness of this abutment wall 8 is less than needle bearing, the internal surface of the abutment wall of being made by aluminum alloy 8 can be owing to needle bearing 10 weares and teares yet.And because pad 12 does not rotate with roller 11, therefore, the internal surface of this abutment wall 8 can not wear and tear owing to contacting with this pad 12.

Like this, because under any circumstance the internal surface of the abutment wall of being made by aluminum alloy 8 can not wear and tear, do not worry producing fine powder, therefore, use in the office, rotation section of roller 11 the overtime frictional resistance moment that produces increase and since the damage of the rotating part that the frictional resistance moment increase causes can both be suppressed.

Although this paper has only introduced specific embodiment of the present invention especially, should be known under the situation that does not break away from the spirit and scope of the present invention and can carry out multiple variation.

As above detailed introduction, according to a first aspect of the invention, because pad inserts between roller and the rocking arm, therefore, roller and rocking arm are not in slidable contact with each other, and this pad does not rotate with roller, at this moment, a significant advantage is the wearing and tearing that suppressed rocking arm.

According to a second aspect of the invention, because swiveling limitation mechanism is located at the select location place that is not positioned on the pitman arm shaft axle center that makes rocking arm and the straight line that the Roller Shaft axle center links to each other, therefore, need on rocking arm, not provide thick especially part to form concave portions, and, because can suppress owing to the reduction that forms the rocking arm rigidity that concave portions causes, therefore, at this moment a significant advantage is to make this rocking arm reduce to minimum.

And, according to a third aspect of the invention we,, this rocking arm is increased because in rocking arm, can provide rotary actuator.In addition, because need in abutment wall, not form concave portions, therefore can not reduce the bearing strength of Roller Shaft.According to a forth aspect of the invention, because carrying out the surface, curved section on pad and rocking arm offset, therefore, offseting of this rotation retainer can not cause wearing and tearing, and because the rigidity of this rotary actuator is owing to this curved section increases, this pad also can attenuation.And, according to a fifth aspect of the invention, because provide this concave portions and need not provide thick especially part, therefore facing on the part of cam, this rocking arm and cam can be arranged to more close each other, thereby can make this valve gear littler and make this motor miniaturization.

Claims

1. rocking arm that is supported on swingably on the pitman arm shaft, this rocking arm comprises:

One roller, this roller are rotatably supported on the Roller Shaft of extending between a pair of abutment wall, and this abutment wall faces toward on the part of cam rocking arm; And

Pad, this pad lay respectively at described Roller Shaft to end portion and abutment wall part respect to one another place,

Described rocking arm is characterised in that:

The swiveling limitation mechanism that is used to limit the rotation of described pad is located between described pad and the described rocking arm;

Described swiveling limitation mechanism comprises and is located on the described pad and the projection that extends radially outwardly and be formed in the described rocking arm and be used for holding therein the concave portions of described projection;

Described concave portions is located at the select location place, and is not positioned at and makes on described pitman arm shaft axle center and the straight line that described Roller Shaft axle center links to each other.

2. rocking arm according to claim 1, wherein: described swiveling limitation mechanism comprises and is located on the described pad and the projection that extends radially outwardly and be located at concave portions facing to the position of the outer surface of described roller, this roller is between described a pair of abutment wall, and this concave portions is used for holding therein described projection.

3. rocking arm according to claim 1 and 2, wherein: described projection is provided with curved section, the contacted inner surfaces of this curved section and described concave portions.

4. rocking arm according to claim 1 and 2, wherein: described concave portions is located at that side that does not face toward described cam with respect to described Roller Shaft of described rocking arm.