JP5171728B2 - Chain sprocket - Google Patents

Description

  The present invention relates to a chain sprocket in which a plurality of teeth are formed on the peripheral surface of a sprocket main body and meshes with a roller, a bush or a link plate, and more particularly to a chain sprocket suitable for a timing drive system of an automobile engine. It is.

  2. Description of the Related Art Conventionally, chain transmission devices that transmit power by hanging a chain on at least two chain sprockets on the drive side and the driven side have been widely used, and it is desirable to reduce the noise level in any application.

  In particular, in automotive engines, in applications such as chain transmissions that transmit the rotation of the crankshaft to the camshaft, the increased awareness of environmental issues has resulted in higher combustion efficiency and higher output. While the load on the chain transmission device transmitted to the vehicle increases, the demand level for automobile noise reduction has become stricter due to increasing user needs, and the meshing sound between the chain and the sprocket has become a level that cannot be ignored.

  In order to reduce the meshing noise between the chain and the sprocket for the chain, a chain sprocket with chamfered shapes on both sides of multiple teeth is used to reduce the impact noise when the chain and the sprocket mesh. Are known.

  In this known chain sprocket 500, as shown in FIG. 7, a plurality of teeth 510 are formed on the peripheral surface of the sprocket body 501, and a chamfered portion 512 is formed on the tip side of both tooth side surfaces 511 of each tooth 510. Even when the alignment between the chain and the sprocket is shifted, interference between the link plate of the chain and the tooth tip of the sprocket is prevented, and the meshing is smoothed to reduce the impact sound (for example, see Patent Document 1). .)

Patent No. 37079797 (pages 4 to 6, FIGS. 1 to 3)

  However, when the known chain sprocket 500 is engaged with a roller chain 520 in which a large number of inner link plates 521 and outer link plates 522 are alternately connected by connecting pins 524, for example, as shown in FIG. Since the cross-section of the teeth 510 is rectangular including the chamfered portion 512, the inner link plate 521 and the side surfaces of the teeth 510 are in line contact or surface contact when the alignment is deviated. There was a problem that noise and vibration were generated due to contact sound and impact sound.

  The present invention solves the problems of the prior art as described above, i.e., the object of the present invention is to provide a peripheral portion of the tooth tip portion that first comes into contact with the chain even when misalignment occurs. The width of the end of the direction is reduced to prevent the chain link plate and the tooth tip from interfering with each other and to make the meshing smooth. Also, avoiding line contact with the chain link plate, sliding friction, sliding noise and impact noise. Is to provide a chain sprocket that reduces noise and vibration.

  The invention according to claim 1 is the chain sprocket in which a plurality of teeth are formed on the peripheral surface of the sprocket body, and the meshing surface of the teeth forms a straight line in the width direction of the teeth of the sprocket body, Both side surfaces of the teeth have curved surfaces that are curved in the circumferential direction of the sprocket body, and the curved surfaces that are curved in the circumferential direction are convex in the circumferential direction at the line position connecting the rotation center of the sprocket body to the center of the tooth tip. The both sides of the tooth have curved surfaces that are curved in an arc shape in the circumferential direction of the sprocket body, and the curved surface that is curved in an arc shape in the circumferential direction is a tooth tip from the tooth bottom side. The said subject is solved by forming in the shape where an arc radius becomes small gradually toward the side.

  In the invention according to claim 2, in addition to the structure of the chain sprocket according to claim 1, both side surfaces of the teeth have curved surfaces curved in the radial direction of the sprocket body, The curved surface is formed so as to bend in a direction in which the width of the tooth becomes narrower toward the tooth tip side from the tooth bottom side on the line connecting the rotation center of the main body to the center of the tooth tip. Is a further solution.

  In the invention according to claim 3, in addition to the structure of the chain sprocket described in claim 1 or 2, both side surfaces of the teeth are curved in an arc shape in the circumferential direction and the radial direction over the entire surface. The above-mentioned problem is further solved by forming the curved surface having a curved surface in the shape of an arc at a line position connecting the center of rotation of the sprocket body to the center of the tooth tip.

  In the invention according to claim 4, in addition to the structure of the chain sprocket according to any one of claims 1 to 3, the curved surface curved in the circumferential direction has a tooth tip from the rotation center of the sprocket body. The problem is further solved by being provided only on the front side in the rotational direction with respect to the line connecting the centers of the two.

  The invention according to claim 1 is a chain sprocket in which a plurality of teeth are formed on the peripheral surface of the sprocket body, and the meshing surfaces of the teeth are linear in the width direction of the teeth of the sprocket body. Has a curved surface that is curved in the circumferential direction of the sprocket body, and the curved surface that is curved in the circumferential direction is formed in a shape in which the position on the line connecting the rotation center of the sprocket body and the center of the tooth tip is the most convex portion in the circumferential direction. Therefore, when the tooth side surface and the link plate of the chain come into contact, the contact part becomes point contact, so even if the alignment side is shifted and the side surface of the tooth and the chain link plate contact, sliding friction The sliding contact noise can be reduced, and noise and vibration can be reduced.

  In addition, both side surfaces of the tooth have curved surfaces that are curved in an arc shape in the circumferential direction of the sprocket body, and the curved surface that is curved in an arc shape in the circumferential direction gradually increases in arc radius from the root side toward the tooth tip side. Because it is formed in a smaller shape, the width of the circumferential end of the tooth tip that contacts first when meshing with the chain can be reduced when there is a shift in alignment. And the tooth tip can be prevented, the meshing can be smoothed and the impact sound can be reduced.

  The chain sprocket according to the second aspect of the invention has the curved surface in which both side surfaces of the teeth are curved in the radial direction of the sprocket body in addition to the effect of the chain sprocket according to the first aspect. The curved curved surface is formed to curve in the direction in which the width of the tooth narrows from the tooth bottom side to the tooth tip side on the line connecting the rotation center of the sprocket body to the center of the tooth tip, thereby shifting the alignment. If this occurs, the width of the circumferential end of the tooth tip that contacts the chain first when meshing can be further reduced, preventing interference between the chain link plate and the tooth tip and smoother meshing. Can be.

  The chain sprocket according to the third aspect of the invention has the effect of the chain sprocket according to the first or second aspect, and the both side surfaces of the teeth are curved in an arc shape in the circumferential direction and the radial direction over the entire surface. The curved shape of the side surface of the tooth is made symmetric with respect to the curved surface that is curved in the radial direction and is formed in an arc shape at a line position connecting the center of the sprocket to the center of the tooth tip. Therefore, it is possible to prevent the interference between the link plate of the chain and the tooth tip in any rotational direction, and to smoothly engage and reduce the impact sound.

  The chain sprocket according to the fourth aspect of the invention has the effect that the chain sprocket according to any one of the first to third aspects exhibits the curved surface curved in the circumferential direction from the rotation center of the sprocket body. Is provided only on the front side in the rotational direction from the line connecting the centers of the chain, preventing interference between the chain link plate and the tooth tip, smoothing the meshing and reducing the impact noise, It is possible to secure the tooth width of the portion that does not occur and prevent a decrease in strength.

The perspective view of the sprocket for chains which is one Example of this invention. 1 is a partially enlarged front view of a chain sprocket according to an embodiment of the present invention. The partially expanded view of FIG. AA sectional drawing of FIG. BB sectional drawing of FIG. The action explanatory view of the chain sprocket which is one example of the present invention. The perspective view of the conventional chain sprocket. The operation explanatory view of the conventional chain sprocket.

  The present invention provides a chain sprocket in which a plurality of teeth are formed on the peripheral surface of the sprocket body, the meshing surfaces of the teeth are linear in the width direction of the sprocket body, and both side surfaces of the teeth are the periphery of the sprocket body. A curved surface curved in the direction, and the curved surface curved in the circumferential direction is formed in a shape having a linear position connecting the rotation center of the sprocket body to the center of the tooth tip as the most convex portion in the circumferential direction. The sprocket body has a curved surface curved in a circular arc shape, and the curved surface curved in a circular arc shape in the circumferential direction is formed into a shape in which the circular arc radius gradually decreases from the root side toward the tooth tip side. Even when there is a slippage, the chain link plate and the tip of the chain are prevented from interfering with each other and the meshing is smoothed. Also, sliding contact friction, sliding contact sound and impact sound are avoided by avoiding line contact with the chain link plate. As long as an effect that reduced noise can be reduced and vibration, specific embodiments thereof are may any be any one.

  In other words, the chain hung around the chain sprocket of the present invention is driven by a cylindrical member, such as a roller chain or bush chain, which is provided at the same interval as the roller or bush on the teeth of the sprocket. Any chain to be transmitted or a member similar to a chain may be used, and any chain or a member similar to a chain that transmits power by engaging a link plate or the like with a sprocket tooth of a silent chain or the like. Also good.

The material for the chain sprocket of the present invention may be any material such as a metal such as steel, ceramic, resin, or a composite material thereof.
In addition, the chain sprocket manufacturing method of the present invention may be any method such as pressing, molding, injection molding, and machining.

  As shown in FIGS. 1 to 5, the chain sprocket 100 according to an embodiment of the present invention has a plurality of teeth 110 formed on the peripheral surface of the sprocket body 101, and the meshing surface of the teeth 110 is the sprocket body. The teeth 110 are linear in the width direction of the teeth 110, and both side surfaces 111 of the teeth 110 are formed in a curved shape curved in the circumferential direction and the radial direction of the sprocket body 101.

  The circumferential curvature of the side surface 111 of the tooth 110 is formed in an arc shape with the position on the line 112 connecting the center of rotation of the sprocket body 101 to the center C of the tooth tip being the most convex portion in the circumferential direction. The radial curvature of the side surface 111 of the tooth 110 is such that the width of the tooth 110 decreases from the root 114 side to the tooth tip 113 side on the line 112 connecting the rotation center of the sprocket body 101 to the center C of the tooth tip. It is formed in the circular arc shape connected smoothly from the side surface of the sprocket main body 101 in the direction.

  Further, as shown in FIGS. 3 to 5, the arcuate curvature in the circumferential direction of the side surface 111 of the tooth 110 is such that the arc radius RA of the side surface 111 in the AA cross section on the tooth bottom 114 side is B on the tooth tip 113 side. The arc radius is gradually reduced from the tooth bottom 114 side toward the tooth tip 113 side so as to be larger than the arc radius RB of the side surface 111 in the −B cross section.

  When the chain sprocket 100 according to the embodiment of the present invention configured as described above is engaged with a roller chain 120 in which a large number of inner link plates 121 and outer link plates 122 are alternately connected by connecting pins 124, for example, FIG. 6, since the side surface 111 of the tooth 110 of the chain sprocket 100 has an arc shape in the circumferential direction and the radial direction, even if the alignment is displaced and the inner link plate 121 and the side surface 111 of the tooth 110 are in contact with each other. Since point contact can be achieved, sliding friction is extremely small, and generation of sliding contact noise and impact noise is suppressed, so that noise and vibration can be prevented.

  Further, since the side surface 111 is curved so that the width of the tooth 110 is closer to the tooth tip 113 and the width becomes narrower toward the front and rear in the circumferential direction, even if the alignment is deviated, the tooth 110 meshes with the roller chain 120. At the start, the inner link plate 121 does not collide with the tooth tip 113 but stays in contact with the side surface 111 and meshes smoothly until the roller 123 seats on the tooth bottom 114 while the inner link plate 121 makes point contact with the side surface 111. Since it advances, generation | occurrence | production of a sliding contact sound and an impact sound is suppressed, and a noise and a vibration can be prevented.

  Furthermore, when the rotation direction is only one direction, in order to suppress the occurrence of sliding contact sound and impact sound at the start of meshing, the curved surface curved in the circumferential direction of the side surface 111 is It suffices if it is provided only on the front side in the rotation direction from the line connecting the rotation center of the chain sprocket 100 to the center of the tooth tip 113, and this ensures the width of the tooth 110 at a portion where no interference occurs. Thus, a decrease in strength can be prevented.

100, 500 ... Sprocket 101, 501 for chain ... Sprocket body 110, 510 ... Teeth 111, 511 ... Side 112 ... Most convex part 512 ... Chamfered part 113 ... Tooth tip 114... Tooth bottom 120 520... Roller chain 121 521... Inner link plate 122 522. Outer link plate 123 523... Roller 124 524.・ Tooth tip center line

Claims (4)

In the chain sprocket in which a plurality of teeth are formed on the peripheral surface of the sprocket body,
The meshing surface of the teeth forms a straight line in the width direction of the teeth of the sprocket body,
Both side surfaces of the teeth have curved surfaces curved in the circumferential direction of the sprocket body,
The curved surface curved in the circumferential direction is formed in a shape having a linear position connecting the center of the tooth tip to the center of the tooth tip as the most convex portion in the circumferential direction,
Both side surfaces of the teeth have curved surfaces curved in an arc shape in the circumferential direction of the sprocket body,
A sprocket for a chain, wherein the curved surface curved in an arc shape in the circumferential direction is formed in a shape in which the arc radius gradually decreases from the tooth bottom side toward the tooth tip side. Both side surfaces of the teeth have curved surfaces curved in the radial direction of the sprocket body,
The curved surface curved in the radial direction is formed so as to bend in a direction in which the width of the tooth becomes narrower from the tooth bottom side to the tooth tip side on the line connecting the rotation center of the sprocket body to the center of the tooth tip. The chain sprocket according to claim 1. Both side surfaces of the teeth have curved surfaces that are curved in an arc shape in the circumferential direction and the radial direction over the entire surface,
3. The chain sprocket according to claim 1, wherein the curved surface curved in the radial direction is formed in an arc shape at a position on a line connecting the rotation center of the sprocket body to the center of the tooth tip. . The curved surface curved in the circumferential direction is provided only on the front side in the rotational direction with respect to a line connecting the rotational center of the sprocket body to the center of the tooth tip. Sprockets for chains described in 1.

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