JP2017166368A - Roller lifter structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller lifter structure capable of suppressing a wear of a lifter guide or a lifter.SOLUTION: A roller lifter 10 is equipped with a roller 80 contacted with an outer peripheral surface of a cam 70; a shaft member 81 which rotatably supports the roller 80; and a cylindrical lifter body 11 which holds axial both end portions of the shaft member 81, and is stored in a guide hole 95 with a circular cross-section provided on a lifter guide 91 so as to reciprocate. Of an outer peripheral surface of the lifter body 11, at a part opposing in a direction orthogonal to an axial direction of the shaft member 81, a non-contacting portion 18 in a form escaping from an inner peripheral surface of the guide hole 95, is provided. A contacting portion 19 is provided, which is contacted with the inner peripheral surface of the guide hole 95 on both sides in a circumferential direction of the non-contacting portion 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a roller lifter structure.

  As this type of roller lifter structure, a structure having a pump lifter used for a fuel supply pump of an internal combustion engine of an automobile is known. For example, the pump lifter disclosed in Patent Document 1 includes a roller that contacts the outer peripheral surface of the cam, a shaft support pin that rotatably supports the roller, and a pair of support portions that hold both axial ends of the shaft support pin. And a cylindrical lifter body having a sliding surface slidable on the inner wall of the cylinder (lifter guide).

JP 2014-1706 A

  By the way, the lifter body reciprocates according to the cam profile of the cam, and receives a component force in a direction intersecting with the moving direction, so that the lifter body tilts to some extent in the gap range with the inner wall of the lifter guide. In this case, since the sliding surface of the lifter has a substantially circular outer peripheral shape, for example, when the inner wall of the lifter guide is arranged along the vertical direction, the shaft support pin of the lifter sliding surface is arranged. The portions facing each other in the direction orthogonal to the axial direction come into contact with the inner wall in a point contact state at the upper end and the lower end. As a result, the contact pressure of the contact portion between the lifter guide and the lifter becomes excessive, and the lifter guide or the lifter may be worn. In particular, since the lifter body is kept in a state in which the rotation is restricted by the rotation preventing portion during the movement, the range of the contact portion does not change in the circumferential direction, and the problem of wear becomes more conspicuous. .

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a roller lifter structure capable of suppressing wear of the lifter guide or the lifter.

  The structure of the roller lifter according to the present invention includes a roller that contacts the outer peripheral surface of the cam, a shaft member that rotatably supports the roller, and a circular cross section provided on the lifter guide that holds both axial ends of the shaft member. A cylindrical lifter body accommodated in the guide hole so as to be reciprocally movable, and a portion of the outer periphery of the lifter body that is opposed to the shaft member in a direction orthogonal to the axial direction of the shaft member. It has a non-contact part of the form which escapes from an internal peripheral surface, and has the feature in having the contact part which contacts the internal peripheral surface of the said guide hole in the circumferential direction both sides of the said non-contact part.

  When the cam rotates, the roller supported by the shaft member is driven to rotate, and the portion of the outer peripheral surface of the lifter body that faces in the direction orthogonal to the axial direction of the shaft member is the end in the moving direction, and the guide hole Point contact with the inner peripheral surface may generate a large contact pressure, and the lifter guide or lifter may be worn. However, according to the present invention, the outer surface of the lifter body has a non-contact portion in a portion facing in the direction orthogonal to the axial direction of the shaft member, and the contact portion is a guide hole on both sides in the circumferential direction of the non-contact portion. Since the structure is in contact with the inner peripheral surface, stress is dispersed as compared with the case of point contact with the inner peripheral surface of the guide hole, and wear of the lifter guide or the lifter can be suppressed.

It is the figure which looked at the roller lifter structure of Example 1 of this invention from the planar view direction. It is a front view of a roller lifter. It is a rear view of a roller lifter. It is sectional drawing at the time of applying a roller lifter to a pump lifter. FIG. 3 is a partially enlarged view corresponding to FIG. 1 in a roller lifter structure according to a second embodiment. FIG. 6 is a partially enlarged view corresponding to FIG. 1 in the roller lifter structure of Embodiment 3.

Preferred embodiments of the present invention are shown below.
The lifter body has a detent portion configured to enter a detent groove provided along an inner circumferential surface of the guide hole, and the non-contact portion is formed on the outer circumferential surface of the lifter body. It is provided on the opposite side of the portion in the radial direction and is not provided on the side of the rotation preventing portion. When the non-rotating portion enters the anti-rotation groove, both circumferential portions of the outer peripheral surface of the lifter body sandwiching the non-rotating portion sandwich both sides in the circumferential direction of the inner circumferential surface of the guide groove. Will come into contact with the part. Therefore, since a point contact state does not occur on the side where the rotation preventing portion of the lifter body is located, it is not necessary to provide a non-contact portion as a wear suppressing means. As a result, the configuration of the lifter body can be simplified.

  Of the inner peripheral surface of the lifter body, a portion facing the non-contact portion on the opposite side in the thickness direction of the lifter body has a circumferential surface along the circumferential direction. According to this, the internal space of the lifter body is not restricted by the presence of the non-contact portion, and the internal space can be used effectively.

<Example 1>
A first embodiment of the present invention will be described with reference to FIGS. The roller lifter structure of the first embodiment exemplifies the structure of a pump lifter applied to the fuel supply device 90 for the internal combustion engine of the automobile shown in FIG.

  The fuel supply device 90 supplies the fuel adjusted to a high pressure by the roller lifter 10 to a fuel chamber of an engine (not shown). The roller lifter 10 is incorporated in a lifter guide 91 of the cylinder head.

  As shown in FIG. 4, the lifter guide 91 includes a housing 92 and a lid member 93 fitted to the upper end portion of the housing 92. The lid member 93 is provided with a through hole 94 having a circular cross section that penetrates in the vertical direction. The plunger 60 is inserted into the through hole 94 of the lid member 93 so as to be reciprocally movable in the vertical direction. The upper end portion of the plunger 60 can be advanced and retracted into a pressure chamber (not shown) communicating with the upper end of the through hole 94. The fuel in the pressure chamber is pressurized by the upper end portion of the plunger 60 entering the pressure chamber.

  A guide hole 95 is provided in the housing 92. The guide hole 95 has a circular cross section, specifically a true circular cross section, and extends in the vertical direction and opens at the lower end of the housing 92. The guide hole 95 is closed at the upper end by a lid member 93 fitted into the housing 92, and is configured to communicate with the through hole 94 coaxially. The lifter body 11 of the roller lifter 10 is inserted into the guide hole 95 of the housing 92 so as to be reciprocally movable in the vertical direction.

  The housing 92 is provided with a detent groove 96 that communicates with the guide hole 95. The anti-rotation groove 96 extends in the vertical direction along the inner peripheral surface of the guide hole 95 and opens at the lower end of the housing 92. The upper end of the guide hole 95 is closed with a lid 93. The length of the guide hole 95 in the vertical direction is set according to the movement stroke (lifter amount) of the roller lifter 10.

  The lifter body 11 has a cylindrical peripheral wall 12 substantially along the vertical direction. The outer peripheral surface of the peripheral wall 12 is disposed along the inner peripheral surface of the guide hole 95, and is accommodated in the guide hole 95 so as to be reciprocally movable and slidable.

  The lifter body 11 has a partition wall 13 that divides the inside of the peripheral wall 12 into upper and lower portions. The partition wall 13 has a flat plate shape along the radial direction, and is integrally formed in the middle of the inner peripheral surface of the peripheral wall 12 in the vertical direction. Of the inner peripheral surface of the peripheral wall 12, the upper portion of the partition wall 13 is a peripheral surface 14 having a circular cross section along the circumferential direction.

  A lower portion of the plunger 60, a retainer 61, and a biasing member 62 are accommodated in the space above the partition wall 13 in the lifter body 11. The retainer 61 has a disk shape along the radial direction, and the lower end portion of the plunger 60 is locked and fixed to the bulging portion of the central portion. The urging member 62 is a spring material composed of a compression coil spring, the lower end of which is in contact with the outer peripheral edge of the upper surface of the retainer 61, and the upper end of which is in contact with the lower surface of the lid member 93 of the lifter guide 91. It can be elastically expanded and contracted in the vertical direction. The urging member 62 urges the lifter body 11 toward the cam 70 side.

  As shown in FIG. 2, a pair of inclined portions 15 are provided at the left and right ends of the lower end portion of the peripheral wall 12, which are gradually inclined toward the lower side. The lifter body 11 also has a pair of support walls 16 that protrude downward from the lower ends of both inclined portions 15. Both the support walls 16 have a flat plate shape and are arranged in parallel to each other.

  Inside the lifter body 11, a roller 80 is accommodated in a space below the partition wall 13 and between the support walls 16. The roller 80 is supported by the shaft member 81 and is rotatable with respect to the shaft member 81 via a bearing 82 (see FIG. 4) such as a needle bearing. The shaft member 81 has a cylindrical pin shape elongated in the axial direction (the X direction in FIGS. 1 to 3), and both end portions in the axial direction are held by both support walls 16.

  The roller 80 is arranged such that its lower end protrudes below the support wall 16, its outer peripheral surface at the lower end is slidably in contact with the outer peripheral surface of the cam 70, and receives the urging force of the urging member 62 to receive the outer peripheral surface of the cam 70. Pressed against. The cam 70 has a substantially triangular outer shape in a side view and is provided on the camshaft 71. The camshaft 71 and the shaft member 81 have axes parallel to each other.

  Further, as shown in FIG. 3, the lifter body 11 is a plate bent so as to protrude downward from the rear edge of the lower end of the peripheral wall 12 (the front side in FIG. 3 is the rear side) and then protrudes to the rear. A piece-like detent 17 is provided. As shown in FIG. 4, the rotation prevention portion 17 enters the rotation prevention groove 96 when the peripheral wall 12 is accommodated in the guide hole 95 and can be displaced in the vertical direction as the peripheral wall 12 moves in the vertical direction. It is said that.

  As shown in FIG. 1, a non-contact portion 18 is provided on the outer peripheral surface of the peripheral wall 12 so as to be retracted inward from a circumferential portion having a circular cross section. In a state where the peripheral wall 12 is accommodated in the guide hole 95, the non-contact portion 18 escapes so as to retract from the inner peripheral surface of the guide hole 95, and is maintained in a non-contact state with the inner peripheral surface of the guide hole 95.

  Here, the non-contact portion 18 is a portion that faces the direction (Y direction in FIG. 1) orthogonal to the axial direction (X direction in FIG. 1) of the shaft member 81 on the outer peripheral surface of the peripheral wall 12. It is provided to extend in a straight line in the vertical direction at a position opposite to the side where the portion 17 is located in the radial direction. More specifically, the non-contact portion 18 has a linear flat surface along the chord direction of the outer periphery of the peripheral wall 12 when viewed from the plan view (see FIG. 1), and the entire length of the peripheral wall 12 in the vertical direction. It extends over and opens at the upper and lower ends of the peripheral wall 12 (see FIG. 2). Further, the non-contact part 18 is provided only at one place in the circumferential direction of the peripheral wall 12. Of the inner peripheral surface of the peripheral wall 12, the portion opposite to the non-contact portion 18 in the thickness direction of the peripheral wall 12 has an arc shape and constitutes a part of the peripheral surface 14. For this reason, the peripheral wall 12 is thinner than the part in which the part which has the non-contact part 18 adjoins.

  As shown in FIG. 1, the outer peripheral surface of the peripheral wall 12 has a contact portion 19 along a circumferential portion having a circular cross section on both sides in the circumferential direction of the non-contact portion 18. In a state where the peripheral wall 12 is accommodated in the guide hole 95, the contact portion 19 is disposed so as to be able to contact along the inner peripheral surface of the guide hole 95. The contact portion 19 is provided in a circular arc shape, specifically, a superior arc shape, in a portion of the outer peripheral surface of the peripheral wall 12 excluding a region corresponding to the non-contact portion 18 and the inclined portion 15.

Next, the operation of the roller lifter 10 according to the first embodiment will be described.
When the cam 70 rotates around the axis of the camshaft 71, the roller 80 is driven to rotate. In the fuel intake process, the lifter body 11 is pressed by the urging force of the urging member 62, the contact portion 19 of the peripheral wall 12 is displaced downward while sliding on the inner peripheral surface of the guide hole 95, and the plunger 60 is the same. The upper end portion of the plunger 60 is retracted from the pressure chamber. On the other hand, in the fuel discharging process, the lifter body 11 resists the biasing force of the biasing member 62 and the contact portion 19 of the peripheral wall 12 is displaced upward while sliding on the inner peripheral surface of the guide hole 95, and the plunger 60 is similarly displaced upward, and the upper end of the plunger 60 enters the pressure chamber. In this way, while the lifter body 11 reciprocates in the vertical direction in the guide hole 95, the distal end portion of the anti-rotation portion 17 enters the anti-rotation groove 96 and is released.

  When the cam 70 rotates, the peripheral wall 12 of the lifter body 11 reciprocates up and down in the vertical direction in accordance with the cam profile of the cam 70, and the axial direction of the shaft member 81 (the axial direction of the cam shaft 71). A slight inclination (cocking) occurs in the gap range with the inner peripheral surface of the guide hole 95 due to a component force in a direction orthogonal to the same) (Y direction in FIG. 1).

  In the case of the first embodiment, a portion of the outer peripheral surface of the lifter body 11 that is opposed in a direction orthogonal to the axial direction of the shaft member 81 has the non-contact portion 18, and the non-contact portion 18 is inside the guide hole 95. Contact portions 19 that are disposed away from the peripheral surface and are located on both sides in the circumferential direction of the non-contact portion 18 are disposed in contact with the inner peripheral surface of the guide hole 95. For example, when the upper end of the lifter body 11 is tilted so as to fall down to the side where the non-contact portion 18 is located, the non-contact portion 18 at the upper end of the lifter body 11 does not contact the inner peripheral surface of the guide hole 95, 11 is in contact with the inner peripheral surface of the guide hole 95. For this reason, the upper end of the lifter body 11 does not come into contact with the inner peripheral surface of the guide hole 95 in a point contact state, and it is possible to avoid a situation where stress is concentrated at one place on the upper end of the lifter body 11.

  Further, the rotation preventing portion 17 is provided in a portion of the outer peripheral surface of the lifter main body 11 that is opposed to the shaft member 81 in the direction orthogonal to the axial direction and that is on the opposite side of the non-contact portion 18 in the radial direction. Therefore, when the upper end of the lifter main body 11 is tilted so as to fall down to the side where the non-contact portion 18 is located, the anti-rotation portion 17 at the lower end of the lifter main body 11 enters into the anti-rotation groove 96 and escapes. Of the outer peripheral surface, the portions on both sides in the circumferential direction with the anti-rotation portion 17 in contact with the inner peripheral surface of the guide hole 95 on both sides in the circumferential direction with the anti-rotation groove 96 interposed therebetween. For this reason, similarly to the above, the lower end of the lifter body 11 does not abut on the inner peripheral surface of the guide hole 95 in a point contact state, and a situation where stress concentrates at one place on the lower end of the lifter body 11 can be avoided. .

  On the other hand, when the upper end of the lifter body 11 is tilted so as to fall down to the side where the detent portion 17 is located, the non-contact portion 18 at the lower end of the lifter body 11 is opposite to the inner peripheral surface of the guide hole 95. By not contacting, the stress applied to the lower end of the lifter body 11 is dispersed, and the anti-rotation portion 17 enters the anti-rotation groove 96 and is released, and the stress applied to the upper end of the lifter body 11 is dispersed.

  As a result, it is possible to prevent the lifter guide 91 or the lifter body 11 from being worn, and it is possible to improve durability and improve the reliability of the movement operation of the lifter body 11.

In the case of the first embodiment, since the non-contact portion 18 is not provided on the outer peripheral surface of the lifter body 11 on the side where the rotation preventing portion 17 is located, the configuration of the lifter body 11 is simplified accordingly. Can be
Further, a portion of the inner peripheral surface of the lifter body 11 facing the non-contact portion 18 on the opposite side in the thickness direction of the lifter body 11 has a circumferential surface 14 along the circumferential direction. Since the perfect circular shape of the inner peripheral surface is maintained, the inner space of the lifter body 11 is not restricted by the presence of the non-contact portion 18, and the retainer 61, the urging member 62, and the plunger 60 are placed in the inner space. It can be accommodated without hindrance.

<Example 2>
FIG. 5 shows a second embodiment of the present invention. The second embodiment is the same as the first embodiment except that the shape of the non-contact portion 18A is different from the first embodiment. For this reason, the same code | symbol is attached | subjected to the structure similar to Example 1, and the description which overlaps with Example 1 is abbreviate | omitted.

  The non-contact portion 18 </ b> A has an arcuate cross-sectional shape that bulges outward in the radial direction when viewed from the plan view, and has a radius of curvature larger than the radius of curvature of the contact portion 19. For this reason, the non-contact portion 18 </ b> A has a shape that continues to the contact portion 19 in a curved shape without a step. When the peripheral wall 12 is accommodated in the guide hole 95, the non-contact portion 18 </ b> A is disposed closer to the inner peripheral surface of the guide hole 95 than the linear non-contact portion 18 </ b> A of the first embodiment. It is kept in a non-contact state with the inner peripheral surface. It should be noted that the position where the non-contact portion 18A is formed (of the outer peripheral surface of the peripheral wall 12 is a portion facing the direction (Y direction in FIG. 5) perpendicular to the axial direction of the shaft member 81 (X direction in FIG. 5)) The position on the opposite side in the radial direction from the side where the stopper 17 is located is the same as in the first embodiment.

  According to the second embodiment, the strength of the peripheral wall 12 of the lifter main body 11 can be ensured satisfactorily, and the appearance is similar to the conventional lifter main body 11, so that the design is not deteriorated.

<Example 3>
FIG. 6 shows a third embodiment of the present invention. The third embodiment is also the same as the first embodiment except that the shape of the non-contact portion 18B is different from that of the first embodiment.

  The non-contact portion 18B has an arcuate cross-sectional shape that bulges inward in the radial direction when viewed from the plan view, and is recessed in a substantially U shape from the contact portions 19 on both sides in the circumferential direction. Of the inner peripheral surface of the peripheral wall 12 of the lifter body 11, the portion opposite to the non-contact portion 18 </ b> B with respect to the thickness direction of the peripheral wall 12 is configured to bulge radially inward, similar to the non-contact portion 18 </ b> B. . The peripheral wall 12 is comprised by the same thickness over the perimeter from the contact part 19 to the non-contact part 18B. The position where the non-contact portion 18B is formed (a portion of the outer peripheral surface of the peripheral wall 12 that faces the direction (Y direction in FIG. 6) orthogonal to the axial direction of the shaft member 81 (X direction in FIG. 6) The position on the opposite side in the radial direction from the side where the position 17 is located is the same as in the first embodiment.

  According to the third embodiment, the non-contact portion 18B can be easily formed even when the roller lifter 10 is downsized.

<Other embodiments>
Other embodiments will be briefly described below.
(1) The structure provided in only the upper end part and lower end part of the part which opposes in the direction orthogonal to the axial direction of a shaft member among the outer peripheral surfaces of the surrounding wall of a lifter main body may be sufficient as a non-contact part.
(2) You may provide a non-contact part in the outer peripheral surface of a lifter main body in the side in which a rotation prevention part is located.
(3) The present invention can be applied to a valve lifter that transmits the rotational force of a cam to a valve that opens and closes an intake / exhaust port in a valve mechanism of a reciprocating engine.

DESCRIPTION OF SYMBOLS 10 ... Roller lifter 11 ... Lifter main body 14 ... Circumferential surface 17 ... Non-rotation part 18 ... Non-contact part 19 ... Contact part 70 ... Cam 80 ... Roller 81 ... Shaft member 91 ... Lifter guide 95 ... Guide hole 96 ... Anti-rotation groove

Claims (3)

A roller in contact with the outer peripheral surface of the cam;
A shaft member that rotatably supports the roller;
A cylindrical lifter body that holds both axial ends of the shaft member and is housed in a guide hole having a circular cross section provided in the lifter guide so as to be reciprocally movable;
Of the outer peripheral surface of the lifter body, a portion that is opposed in a direction orthogonal to the axial direction of the shaft member has a non-contact portion that escapes from the inner peripheral surface of the guide hole, and the circumferential direction of the non-contact portion A roller lifter structure having a contact portion that contacts the inner peripheral surface of the guide hole on both sides.   The lifter body has a detent portion configured to enter a detent groove provided along an inner circumferential surface of the guide hole, and the non-contact portion is formed on the outer circumferential surface of the lifter body. The roller lifter structure according to claim 1, wherein the roller lifter structure is provided on a side opposite to the radial direction of the portion and not provided on the side of the rotation preventing portion.   The inner peripheral surface of the lifter body has a circumferential surface along the circumferential direction at a portion facing the non-contact portion on the opposite side in the thickness direction of the lifter body. Roller lifter structure.

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