JP6026242B2 - Rocker arm - Google Patents

Description

  The present invention relates to a rocker arm mounted on an internal combustion engine.

  The rocker arm plays a role of converting a rotary motion of a valve mechanism in an internal combustion engine, that is, a cam rotating in conjunction with a crankshaft, into a reciprocating motion of a valve shaft of the intake valve or exhaust valve of the internal combustion engine. Such a rocker arm has a roller that is in rolling contact with a camshaft that rotates at a high speed. As an example of an internal combustion engine provided with this type of rocker arm, one described in Patent Document 1 is known.

JP-A-5-240008

  The roller described above is supported by a roller support shaft in a rotatable state. To reduce the contact resistance with the roller support shaft that occurs when the roller rotates, for example, as shown in FIG. It is preferable to secure a clearance between 90 and the roller support shaft 91. However, since the roller 90 is in point contact with the roller support shaft 91 at one location in the circumferential direction, the contact position between the roller 90 and the roller support shaft 91 as the cam shaft 92 rotates ( There is a risk of fluctuation in a pendulum shape in the circumferential direction. When the contact position fluctuates as described above, the rotation of the roller 90 becomes unstable and wear and friction may increase, or the roller 90 may slip. In addition, when the roller 90 is brought into the point contact state at one place as described above with respect to the roller support shaft 91, the roller 90 is inclined with respect to the roller support shaft 91 as shown in FIG. There is also a possibility that wear and friction increase due to displacement.

  The present invention has been completed based on the above circumstances, and an object thereof is to suppress wear and friction.

  The rocker arm of the present invention has a roller having a support shaft insertion hole, a pair of side walls arranged so as to sandwich the roller, a roller accommodating portion for accommodating the roller, and a bridge between the pair of side walls. A roller support shaft that rotatably supports the roller by being inserted into the support shaft insertion hole of the roller, and a peripheral surface of the support shaft insertion hole of the roller and the roller support shaft. At least at least one of the rollers and the roller support shaft is formed in at least two positions separated from each other in the circumferential direction, and at least abuts against the other side in a form having a non-contact space where the opposed peripheral surfaces are not in contact with each other. Two contact portions.

  In this way, the roller disposed in a form sandwiched between the pair of side walls of the roller accommodating portion is disposed in a form spanning between the pair of side walls, and is inserted into the support shaft insertion hole of the roller. It is rotatably supported by a support shaft. Even when a clearance is generated between the opposed peripheral surfaces of the roller support shaft insertion hole and the roller support shaft, at least two abutments formed at two positions separated in the circumferential direction on at least one of the opposed peripheral surfaces. The contact portion abuts against the other side in a form having a non-contact space in which the opposing peripheral surfaces are not in contact with each other, so that the rollers are always at least at two positions spaced apart in the circumferential direction regardless of the presence of clearance. It is supported by a roller support shaft. This makes it difficult for the contact position between the roller and the roller support shaft to vary in the circumferential direction, thereby stabilizing the rotation of the roller. In addition, since the roller is always supported by the roller support shaft at at least two positions, it is difficult for the roller to be displaced so that its axis is inclined with respect to the roller support shaft, and the rotation of the roller is also stabilized. Will be. In addition, since the oil tends to stay in the non-contact space provided between the at least two contact portions, the rotation of the roller becomes smooth. As described above, wear and friction are suitably suppressed.

The following configuration is preferable as an embodiment of the present invention.
(1) Whereas the roller is formed so that the support shaft insertion hole has a circular cross section, the roller support shaft has a columnar shape and is partially cut away at the outer periphery. A cutout portion is formed, and at least a pair of the contact portions are arranged at both end positions in the circumferential direction of the cutout portion. In this case, since the abutting portions are arranged at both end positions in the circumferential direction in the notched portion formed by partially notching the outer peripheral edge portion of the cylindrical roller support shaft, the roller temporarily Compared with the case where the contact portion is formed by processing the hole edge portion of the support shaft insertion hole, the processing becomes easier, which is preferable in manufacturing the roller support shaft.

(2) The notch is formed over the entire length of the roller support shaft. In this way, compared to the case where the notch is partially formed in the length direction of the roller support shaft, the processing required to form the notch becomes easier and the roller support shaft is manufactured. This is preferable.

(3) The notch is linearly formed along a string connecting at least two of the contact portions. In this way, the processing required to form the notch is easier than when the notch is formed along a curve connecting at least two abutting portions on the roller support shaft. This is suitable for manufacturing the roller support shaft.

(4) The roller support shaft is provided so as to be fixed to the pair of side walls. If it does in this way, a roller which rotates can be supported more stably because a roller support axis is fixed to a pair of side walls.

(5) Whereas the roller is formed so that the support shaft insertion hole has a circular cross section, the roller support shaft has a columnar shape and an upper portion in the vertical direction of the outer peripheral edge thereof. It has a notch part formed by notching an edge part, and the contact part is arranged in a pair at both end positions in the circumferential direction in the notch part, and with respect to the center of the roller support shaft. The angle is less than 180 degrees. If it does in this way, a pair of contact part will be in the both-ends position about the peripheral direction in the notch part formed by notching the upper edge part about the perpendicular direction among the outer peripheral parts of the cylindrical roller support shaft. The angle formed by the pair of contact portions with respect to the center of the roller support shaft is less than 180 degrees, and therefore, between the opposed peripheral surfaces of the roller support shaft insertion hole and the roller support shaft. Even when the clearance is generated, the roller is stably supported by the pair of contact portions from the lower side in the vertical direction. As described above, since the roller is stably supported by the pair of contact portions, the number of contact points between the roller and the roller support shaft can be minimized, and the contact resistance can be kept as low as possible. it can. Thereby, wear and friction are more suitably suppressed.

(6) The roller support shaft is rotatably supported with respect to the pair of side walls. In this way, since the roller support shaft is not fixed to the pair of side walls, the roller support shaft is not required to be fixed during manufacturing.

(7) The abutting portions are arranged at substantially equal angular intervals in at least three positions spaced in the circumferential direction. In this way, even if the position of the abutting portion varies in the circumferential direction as the roller support shaft is rotated with respect to the pair of side walls, each of the portions disposed at least at three positions separated in the circumferential direction is provided. By making the angular intervals between the contact portions substantially equal, it is possible to stably support the roller.

  According to the present invention, wear and friction can be suppressed.

Sectional drawing showing the whole rocker arm structure concerning Embodiment 1 of this invention Top view of rocker arm Perspective view of roller support shaft Top view of roller and roller support shaft Side view of roller and roller support shaft Side sectional view continuously showing the rotation operation of the roller accompanying the rotation of the camshaft in the order of (A) to (D) The perspective view of the roller support shaft which concerns on Embodiment 2 of this invention. The top view of the rocker arm concerning Embodiment 3 of the present invention. Side view of roller and roller support shaft Side view of roller and roller support shaft according to Embodiment 4 of the present invention Side sectional view showing rotation operation of roller along with rotation of camshaft according to background art continuously in order of (A) to (D) Top view of roller and roller support shaft

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an upper part of a cylinder head 1, in which a valve operating device constituted by a pivot 2, a camshaft 3, a valve 4, a valve spring 5 and a rocker arm 6 is provided. In addition, a part of each drawing shows an X axis, a Y axis, and a Z axis, and each axis direction is drawn to be a direction shown in each drawing. Of these, the Z-axis direction substantially coincides with the vertical direction, and both the X-axis direction and the Y-axis direction substantially coincide with the horizontal direction. In addition, unless otherwise noted, the vertical direction is used as a reference for upper and lower descriptions.

  As shown in FIG. 1, the rocker arm 6 is a roller rocker arm having a roller 7, and the roller 7 is in contact with the outer peripheral surface of the cam 3 </ b> A of the camshaft 3. One end of the rocker arm 6 is formed with a swing fulcrum portion 8 that contacts the upper end of the pivot 2 of the lash adjuster, and the other end is formed with a valve contact portion 10 that engages with the upper end of the valve stem 4A of the valve 4. Has been. Thus, in the valve operating device described above, as the camshaft 3 rotates, the rocker arm 6 swings around the swinging fulcrum 8 and the upper end side of the valve stem 4A is pressed against the valve spring 5 at this time. Then, the valve 4 opens and closes the intake and exhaust ports of the engine at a predetermined timing.

  As shown in FIGS. 1 and 2, the rocker arm 6 includes a main body 9, a roller 7 and a roller support shaft 13 incorporated in the main body 9. The main body portion 9 is integrally formed by bending a metal plate material with a press, and a central portion thereof is a roller accommodating portion 11 for accommodating the roller 7. The roller accommodating portion 11 is open on both the upper and lower sides in the vertical direction (Z-axis direction), and the roller 7 is accommodated through the opening. The roller accommodating part 11 has a pair of side walls 12 arranged so as to sandwich the roller 7 from both sides in the thickness direction (axial direction of the rotation shaft). Between the pair of side walls 12, a roller support shaft 13 for supporting the roller 7 rotatably is spanned. In the pair of side walls 12, shaft end portion insertion holes 12A for penetrating both end portions 13A of the roller support shaft 13 are formed penetratingly along the thickness direction. The shaft end insertion hole 12A has a circular shape when viewed from the side (the direction along the Y-axis direction).

  As shown in FIGS. 1 and 2, the roller 7 has a generally cylindrical shape (a donut shape when viewed from the side) as a whole, and the central side portion 13 </ b> B of the roller support shaft 13 is inserted into the center position thereof. The support shaft insertion hole 7A is formed through the width direction (Y-axis direction). The roller 7 has a circular shape in which the outer peripheral surface and the inner peripheral surface are both concentric when viewed from the side, that is, the direction along the rotation axis (Y-axis direction), and has a thickness dimension (outer diameter and inner diameter) over the entire circumference. (Difference with dimensions) is almost constant. The roller support shaft 13 has a substantially cylindrical shape as a whole, and both end portions 13A in the length direction (axial direction, Y-axis direction) are respectively inserted into shaft end portion insertion holes 12A formed in the pair of side walls 12. It is fixed to each side wall 12 by being caulked. The roller support shaft 13 can support the roller 7 in a rotatable state by a central portion 13B excluding both end portions 13A in the length direction, and constitutes a rotation shaft of the roller 7.

  Further, as shown in FIGS. 1 and 2, the both side walls 12 constituting the roller accommodating portion 11 are formed with a height dimension such that the accommodated rollers 7 protrude outward slightly in the vertical direction. . Further, one end side of the main body portion 9 is the above-described swing fulcrum portion 8, which is swelled in a dome shape by drawing so as to be covered with the upper end portion of the pivot 2 in alignment. A receiving convex portion 15 is formed. On the other hand, the width of the valve contact portion 10 is gradually reduced from the roller accommodating portion 11, and the lower surface thereof is in contact with the cap 14 described below. The cap 14 is made of metal (in this embodiment, for example, SCM415 material is used), and is fitted to the upper end of the valve stem 4A of the valve 4.

  By the way, in this embodiment, as shown in FIG. 1, the inner diameter dimension of the roller 7 (the diameter dimension of the support shaft insertion hole 7A) is larger than the outer diameter dimension of the roller support shaft 13. The clearance C having the above-described dimensional difference is provided between the opposed peripheral surfaces of the roller support shaft 13 and the roller. In this way, the outer peripheral surface of the roller support shaft 13 is point-contacted with the inner peripheral surface of the support shaft insertion hole 7A of the roller 7 when viewed from the side (from the axial direction of the roller support shaft 13). Therefore, the contact resistance generated when the roller 7 rotates is reduced, and it is possible to suppress wear and friction. Since the roller 7 is supported from the lower side in the vertical direction by the roller support shaft 13, the center 13C of the roller support shaft 13 is unevenly distributed on the upper side in the vertical direction with respect to the center 7C of the roller 7 (see FIG. 5). ) The contact position between the roller 7 and the roller support shaft 13 is arranged in the upper part in the vertical direction in both of them, and the clearance C provided between the opposed peripheral surfaces is arranged below the contact position. become.

  In addition, as shown in FIGS. 3 and 5, the roller support shaft 13 according to the present embodiment has a notch 16 formed by partially notching the outer peripheral edge. A pair of contact portions 17 that are in contact with the roller 7 are provided at both end positions in the circumferential direction (direction around the axis) of the roller support shaft 13. The pair of abutting portions 17 are arranged at two positions separated from each other in the circumferential direction on the outer peripheral surface of the roller support shaft 13, that is, on the peripheral surface facing the inner peripheral surface of the support shaft insertion hole 7 </ b> A of the roller 7. Point contact is made with the inner peripheral surface of the support shaft insertion hole 7A of the roller 7 as viewed (from the axial direction of the roller support shaft 13) (see FIG. 3). The space for forming the notch 16 in the roller support shaft 13 is provided between the pair of contact portions 17 when viewed from the side, and the opposed peripheral surfaces of the roller 7 and the roller support shaft 13 are not in contact with each other. The non-contact space 18 is maintained.

  Specifically, as shown in FIG. 5, the pair of contact portions 17 has an angle θ formed with respect to the center 13 </ b> C of the roller support shaft 13 that is less than 180 degrees, specifically a numerical value that is less than 90 degrees. Has been. Therefore, when the roller support shaft 13 is viewed from the side along the axial direction, the string formed by the straight line connecting the pair of contact portions 17 does not pass through the center 13C of the roller support shaft 13. The cutout portion 16 is formed by cutting the roller support shaft 13 linearly along a string connecting the pair of contact portions 17 when viewed from the side, and the formation surface 16A is substantially flat over the entire area. It has a shape. The notch portion 16 is formed by notching the upper edge portion in the vertical direction of the roller support shaft 13 fixed to the pair of side walls 12, and the forming surface 16A is parallel to the horizontal direction. The In other words, the roller support shaft 13 is fixed to the side wall 12 in a posture in which the notch portion 16 faces the upper side in the vertical direction and the forming surface 16A substantially coincides with the horizontal direction. Accordingly, the non-contact space 18 provided between the pair of contact portions 17 is located on the upper side in the vertical direction with respect to the roller support shaft 13. The non-contact space 18 includes a pair of abutments of an arc connecting the pair of abutting portions 17 on the inner peripheral surface of the support shaft insertion hole 7A of the roller 7 and an outer peripheral surface of the central side portion 13B of the roller support shaft 13. It is surrounded by a string connecting the portions 17 (formation surface 16A of the notch 16), and is constituted by an arcuate space when viewed from the side. The non-contact space 18 opens in a gap (see FIG. 4) between the roller 7 and the pair of side walls 12.

  As shown in FIGS. 3 and 4, the notch 16 has both ends opposed to the pair of side walls 12 in addition to the entire area of the central side portion 13 </ b> B facing the roller 7 and not facing the roller 7. It is also formed over the entire area of the portion 13A, that is, it is formed over the entire length along the length direction of the roller support shaft 13. Accordingly, as shown in FIG. 4, the pair of contact portions 17 are formed so as to extend along the Y-axis direction over the entire length of the central portion 13 </ b> B facing the roller 7 of the roller support shaft 13. At the same time, line contact is made at two positions spaced in the X-axis direction with respect to the inner peripheral surface of the support shaft insertion hole 7A of the roller 7 as viewed from above in the vertical direction. Further, a space similar to the non-contact space 18 is also provided between both end portions 13A in the length direction of the roller support shaft 13 and the shaft end portion insertion holes 12A of the pair of side walls 12 (FIG. 1). See).

  This embodiment has the structure as described above, and the operation thereof will be described subsequently. When the camshaft 3 rotates with the rotation of the crankshaft of the engine, the cam 3A rotates. When the cam 3A rotates, the roller 7 that is in contact with the peripheral surface of the cam 3A is pressed by the cam 3A. When the roller 7 is pressed by the cam 3 </ b> A, the rocker arm 6 performs a swinging motion about the swinging fulcrum portion 8 that contacts the pivot 2. As a result, the cap 14 fitted to the upper end of the valve stem 4A of the valve 4 is pressed from above by the valve contact portion 10, so that each intake / exhaust port of the engine is opened and closed at a predetermined timing. ing. Next, the rotation operation of the roller 7 accompanying the rotation of the cam 3A will be described in detail.

  When the cam 3A is rotated by an angle of slightly less than 180 degrees from the state shown in FIG. 6A, the bulging portion 3A1 of the cam 3A is brought into contact with the roller 7 as shown in FIG. When the cam 3A further rotates from the state shown in FIG. 6B to the state shown in FIG. 6C, the roller 7 is pressed downward by the bulging portion 3A1, so that the rocker arm 6 swings. The fulcrum part 8 is pivotally displaced downward with the fulcrum part 8 as a fulcrum. Thereafter, during the period from the state shown in FIG. 6C to the state shown in FIG. 6D, the contact position between the bulging portion 3A1 of the cam 3A and the roller 7 is displaced upward. The rocker arm 6 is swung upwardly with the rocking fulcrum 8 as a fulcrum.

  As the cam 3A rotates, the roller 7 is rotated with respect to the roller support shaft 13 while receiving a pressing force from the cam 3A, as shown in FIGS. . In addition, since the roller support shaft 13 is fixed to the pair of side walls 12, it does not rotate following the roller 7. At this time, the roller 7 is supported from the lower side at two positions spaced apart in the circumferential direction by a pair of contact portions 17 provided on the roller support shaft 13, so that the cam 3A rotates (see FIG. 6). During the period from (A) to (D), the contact position between the roller 7 and the roller support shaft 13 hardly varies in the circumferential direction. Thus, since the roller 7 is always supported by the pair of contact portions 17 at a fixed position even during rotation, the contact position is only one place as in the prior art, and the roller 7 rotates around the roller. Compared to the one that changes in the direction (see FIG. 11), the rotational operation is stable despite the presence of the clearance C. In addition, the non-contact space 18 provided between the pair of contact portions 17 is arranged on the upper side with respect to the roller support shaft 13 so that the oil is liable to stay, and the non-contact space 18 comes into contact with the staying oil. The frictional resistance generated at the contact portion between the portion 17 and the roller 7 becomes small. Furthermore, as shown in FIG. 4, the pair of contact portions 17 extend linearly along the axial direction (Y-axis direction) of the roller support shaft 13 and are parallel to each other. It is difficult for the roller 7 to be displaced so that the axis of the roller 7 is inclined with respect to the roller support shaft 13, which also makes the rotation operation of the roller 7 more stable. As described above, wear and friction that can occur between the roller 7 and the roller support shaft 13 are suitably suppressed.

  As described above, the rocker arm 6 of the present embodiment has the roller 7 having the support shaft insertion hole 7A, the pair of side walls 12 arranged so as to sandwich the roller 7, and the roller accommodating portion 11 that accommodates the roller 7. The roller support shaft 13 is arranged in a manner that spans between the pair of side walls 12 and is rotatably inserted into the support shaft insertion hole 7A of the roller 7, and the support shaft insertion hole of the roller 7 7A and at least one of the opposed peripheral surfaces of the roller support shaft 13 are formed in at least two positions spaced in the circumferential direction of the roller 7 and the roller support shaft 13, and the opposed peripheral surfaces are not in contact with each other. And at least two abutting portions 17 that abut against the other side in a form having a space 18.

  In this way, the roller 7 that is disposed between the pair of side walls 12 included in the roller accommodating portion 11 is disposed so as to bridge between the pair of side walls 12, and the support shaft insertion hole that the roller 7 has. It is rotatably supported by a roller support shaft 13 inserted through 7A. Even when the clearance C is generated between the opposed peripheral surfaces of the support shaft insertion hole 7A of the roller 7 and the roller support shaft 13, the clearances are formed at two positions separated in the circumferential direction on at least one of the opposed peripheral surfaces. The at least two abutting portions 17 abut on the other side in a form having a non-contact space 18 in which the opposing circumferential surfaces are not in contact with each other, so that the roller 7 always has at least a circumference regardless of the presence of the clearance C. It is supported by the roller support shaft 13 at two positions separated in the direction. As a result, the contact position between the roller 7 and the roller support shaft 13 does not easily change in the circumferential direction, and the rotation of the roller 7 becomes stable. In addition, since the roller 7 is always supported by the roller support shaft 13 at at least two positions, it is difficult for the roller 7 to be displaced with respect to the roller support shaft 13 so that the axis thereof is inclined. The rotation of 7 becomes stable. In addition, since oil tends to stay in the non-contact space 18 provided between the at least two contact portions 17, the rotation of the roller 7 becomes smooth. As described above, wear and friction are suitably suppressed.

  The roller 7 is formed so that the support shaft insertion hole 7A has a circular cross section, whereas the roller support shaft 13 is formed by forming a columnar shape and partially cutting away the outer peripheral edge thereof. The notch part 16 is provided, and at least a pair of the abutting parts 17 are arranged at both end positions in the circumferential direction of the notch part 16. In this way, the contact portions 17 are arranged at both end positions in the circumferential direction of the notch portion 16 formed by partially notching the outer peripheral edge portion of the cylindrical roller support shaft 13. As compared with the case where the contact portion is formed by processing the hole edge portion of the support shaft insertion hole 7 </ b> A of the roller 7, the processing becomes easier, which is preferable in manufacturing the roller support shaft 13.

  Further, the notch 16 is formed over the entire length of the roller support shaft 13. In this way, as compared with the case where the notch is partially formed in the length direction of the roller support shaft 13, the processing required for forming the notch 16 is easier, and the roller support shaft 13 is suitable for manufacturing.

  The notch 16 is formed linearly along a string connecting at least two abutments 17. In this way, compared with the case where the notch is formed in a shape along the curve connecting at least two abutting portions 17 on the roller support shaft 13, the processing necessary for forming the notch 16 is further increased. It becomes easy and suitable for manufacturing the roller support shaft 13.

  The roller support shaft 13 is provided so as to be fixed to the pair of side walls 12. In this way, the roller support shaft 13 is fixed to the pair of side walls 12 so that the rotating roller 7 can be supported more stably.

  The roller 7 is formed so that the support shaft insertion hole 7A has a circular cross section, whereas the roller support shaft 13 has a columnar shape and the upper edge in the vertical direction of the outer peripheral edge portion. A pair of contact portions 17 are arranged at both end positions in the circumferential direction of the notch 16 and are formed with respect to the center of the roller support shaft 13. The angle is arranged to be less than 180 degrees. In this way, a pair of abutting portions are provided at both end positions in the circumferential direction of the notch 16 formed by notching the upper edge in the vertical direction of the outer peripheral edge of the cylindrical roller support shaft 13. Since the contact portion 17 is formed and the angle formed by the pair of contact portions 17 with respect to the center of the roller support shaft 13 is less than 180 degrees, the support shaft insertion hole 7A of the roller 7 and the roller support shaft Even when the clearance C is generated between the peripheral surfaces facing the roller 13, the roller 7 is stably supported by the pair of contact portions 17 from the lower side in the vertical direction. As described above, since the roller 7 is stably supported by the pair of contact portions 17, the number of contact points between the roller 7 and the roller support shaft 13 can be minimized, and the contact resistance is minimized. It can be kept low. Thereby, wear and friction are more suitably suppressed.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG. In this Embodiment 2, what changed the formation range of the notch part 116 is shown. In addition, the overlapping description about the same structure, an effect | action, and effect as above-mentioned Embodiment 1 is abbreviate | omitted.

  As shown in FIG. 7, the roller support shaft 113 according to the present embodiment is selectively formed with a notch 116 only at the central portion 113B in the length direction, and the notches 116 are formed at both ends 113A. It is set as the structure which is not formed. That is, both end portions 113A of the roller support shaft 113 and shaft end portion insertion holes (see FIG. 1) formed in the pair of side walls are both circular and have similar shapes. . Accordingly, the roller support shaft 113 is fixed to the pair of side walls in a form having almost no clearance between the opposing peripheral surfaces of the both end portions 113A and the shaft end portion insertion hole. Thereby, the roller support shaft 113 can be more firmly fixed to the pair of side walls.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIG. 8 or FIG. In the third embodiment, the roller support shaft 213 is movable with respect to the side wall 212, and the shape and the number of contact portions 217 are changed. In addition, the overlapping description about the same structure, an effect | action, and effect as above-mentioned Embodiment 1 is abbreviate | omitted.

  As shown in FIG. 8, the roller support shaft 213 according to the present embodiment has a length that is larger than the distance between the outer surfaces of the pair of side walls 212, and protrudes outward from the outer surface of each side wall 212. Each of these portions is struck to form a retaining portion 19 that is larger than the diameter of the shaft end portion insertion hole 212A and is locked to the edge of the shaft end portion insertion hole 212A. The pair of retaining portions 19 prevent the roller support shaft 213 from coming off. The roller support shaft 213 has a diameter that is slightly smaller than the diameter of the shaft end insertion hole 212 </ b> A, so that the roller support shaft 213 can rotate with respect to the pair of side walls 212. Accordingly, the roller support shaft 213 is also rotated following the rotation of the roller 207 as the cam rotates.

  As shown in FIG. 9, the roller support shaft 213 has a substantially cylindrical shape as a whole, but a plurality of cutout portions 216 that partially cut out the outer peripheral edge portion thereof are provided intermittently in the circumferential direction. Yes. A total of six cutouts 216 are arranged at substantially equal angular intervals on the outer peripheral edge of the roller support shaft 213, and the formation surface 216A has a substantially flat shape. As a result, the roller support shaft 213 has a substantially regular hexagonal shape when viewed from the side, and the six apexes thereof are contact portions 217 with which the rollers 207 are contacted. That is, a total of six contact portions 217 are arranged at substantially equal angular intervals on the outer peripheral surface of the roller support shaft 213, and are viewed from the side with respect to the inner peripheral surface of the support shaft insertion hole 207 </ b> A of the roller 207. Contact is made in a point contact state. Accordingly, the roller 207 can be stably supported by the roller support shaft 213 regardless of the configuration in which the roller support shaft 213 is rotated following the rotation of the roller 207. Between the contact portions 217 adjacent to each other in the circumferential direction of the roller support shaft 213, non-contact spaces 218 in which the opposed peripheral surfaces of the roller 207 and the roller support shaft 213 are not in contact with each other are disposed. A total of six non-contact spaces 218 are arranged at substantially equal angular intervals, like the notches 216.

  As described above, according to this embodiment, the roller support shaft 213 is rotatably supported with respect to the pair of side walls 212. In this way, since the roller support shaft 213 is not fixed to the pair of side walls 212, it is not necessary to fix the roller support shaft 213 during manufacturing.

  The abutting portions 217 are arranged at substantially equal angular intervals in at least three positions separated in the circumferential direction. In this way, even if the position of the contact portion 217 varies in the circumferential direction as the roller support shaft 213 is rotated with respect to the pair of side walls 212, the roller support shaft 213 is arranged in at least three positions separated in the circumferential direction. Since the angular intervals between the contact portions 217 are substantially equal, the roller 207 can be stably supported.

<Embodiment 4>
Embodiment 4 of the present invention will be described with reference to FIG. In the fourth embodiment, the shapes of the roller support shaft 313 and the support shaft insertion hole 307A of the roller 307 are changed from the above-described third embodiment. In addition, the overlapping description about the same structure, effect | action, and effect as above-mentioned Embodiment 3 is abbreviate | omitted.

  As shown in FIG. 10, the roller support shaft 313 according to the present embodiment has a columnar shape as a whole, and its outer peripheral surface has a circular shape when viewed from the side over the entire length. On the other hand, the roller 307 has a circular outer shape when viewed from the side, while the inner peripheral surface of the support shaft insertion hole 307A has a regular hexagonal shape when viewed from the side. The inner peripheral surface of the support shaft insertion hole 307A of the roller 307 is composed of six flat surfaces, and each surface forms a tangent to the outer peripheral surface of the roller support shaft 313 when viewed from the side, and the contact portion thereof is A contact portion 317 is formed. That is, in this embodiment, the contact part 317 is provided on the roller 307 side. Similar to the third embodiment, six contact portions 317 are intermittently arranged side by side at substantially equal angular intervals in the circumferential direction of the roller 307. Therefore, as in the third embodiment, the roller 307 can be stably supported by the roller support shaft 313 regardless of the configuration in which the roller support shaft 313 is rotated following the rotation of the roller 307. Is done. Further, between the contact portions 317 adjacent to each other in the circumferential direction of the roller 307, non-contact spaces 318 in which the opposing peripheral surfaces of the roller 307 and the roller support shaft 313 are not in contact with each other are disposed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In each of the above-described embodiments, the case where the contact portion is provided as a non-circular shape when viewed from the side is shown on either one of the opposed peripheral surfaces of the roller and the roller support shaft. It is also possible to provide both the abutting portions by making the shape of the opposed peripheral surfaces of the roller and the roller support shaft both non-circular when viewed from the side.

  (2) In each of the above-described embodiments, the cut surface formed on the roller or the roller support shaft has a flat surface. However, the cut surface formed on the roller or the roller support shaft has, for example, It is also possible to have a curved surface shape such as an arcuate surface. In that case, the formation surface of the notch portion having a curved surface is recessed with respect to the string connecting both end positions (between contact portions) of the formation surface, or both end positions (between contact portions) of the non-formation surface It is possible to adopt a form that bulges against the string connecting the two.

  (3) In the first to third embodiments described above, the notch portion formed in the roller support shaft has a range that extends over the entire length of the roller support shaft or only the central side portion. It is also possible to form a notch in only a part. In that case, in the portion where the notch portion is formed in the central portion facing the roller, a plurality of contact portions are in point contact with the roller, but the notch portion is not formed. About a part, it becomes the structure which carries out point contact at one place with respect to a roller. In adopting this configuration, for example, the formation position of the notch can be set to the central position of the central portion.

  (4) In Embodiments 1 and 2 described above, the roller support shaft is provided with two contact portions, but it is also possible to provide the roller support shaft with three or more contact portions.

  (5) In the first and second embodiments described above, the roller support shaft is a separate part from the pair of side walls and fixed by caulking to the pair of side walls. However, a method other than caulking (for example, welding) Etc.).

  (6) In the first and second embodiments described above, the roller support shaft is a separate part from the pair of side walls and is fixed to the pair of side walls. It is also possible to adopt a configuration in which the roller support shaft is integrally formed on either one of the pair of side walls. In that case, it is possible to adopt a configuration in which the shaft end portion insertion hole is not formed in the side wall integrally formed with the roller support shaft.

  (7) In the above-described third and fourth embodiments, the roller or roller support shaft is provided with six contact portions. However, the roller or roller support shaft has two to five contact portions, or It is also possible to provide seven or more.

  (8) In Embodiments 3 and 4 described above, the roller or roller support shaft has six contact portions arranged at substantially equal angular intervals. However, the roller or roller support shaft has a plurality of contact portions. Those arranged at non-equal angular intervals are also included in the present invention.

  (9) In the first embodiment described above, the shaft end portion insertion holes formed in the pair of side walls have a circular shape when viewed from the side, and are different in shape from both ends of the roller support shaft. However, it is also possible to make the shaft end portion insertion hole have a shape similar to both end portions of the roller support shaft.

  7, 207, 307... Roller, 7A, 207A, 307A... Support shaft insertion hole, 11... Roller receiving portion, 12, 212 .. Side wall, 12A, 212A .. Shaft end insertion hole, 13, 113, 213, 313. Support shaft, 16, 116, 216 ... notch, 17, 217, 317 ... contact part, 18, 218, 318 ... non-contact space

Claims (4)

A roller having a support shaft insertion hole;
A roller accommodating portion that has a pair of side walls arranged so as to sandwich the roller and accommodates the roller;
A roller support shaft that is arranged in a form spanning between the pair of side walls, and is rotatably supported by being inserted into the support shaft insertion hole of the roller;
The roller is formed in at least three positions spaced apart from each other in the circumferential direction of the roller and the roller support shaft in at least one of the opposed peripheral surfaces of the roller support shaft and the support shaft insertion hole. Comprising at least three abutting portions that abut on the other side in a form having a non-contact space where they are not in contact with each other;
The roller support shaft is rotatably supported with respect to the pair of side walls,
The abutment portion is a rocker arm that is disposed at approximately equiangular intervals in at least three positions spaced apart in the circumferential direction. The roller is formed such that the support shaft insertion hole has a circular cross section, whereas the roller support shaft is formed by forming a columnar shape and partially cutting away the outer peripheral edge thereof. Has a notch,
The rocker arm according to claim 1, wherein at least a pair of the abutting portions are disposed at both end positions in the circumferential direction of the cutout portion.   The rocker arm according to claim 2, wherein the notch is formed over the entire length of the roller support shaft.   The rocker arm according to claim 2 or 3, wherein the notch is formed linearly along a string connecting at least two of the abutting portions.

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