JP2009210015A - Chain guide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain guide having in its guide surface no border line portion subjected to serious wear and prevented from applying excess load to a chain or a large surface pressure between the chain and the guide surface. <P>SOLUTION: The chain guide includes the guide surface that makes sliding contact with the chain. The guide surface is configured to protrude toward the chain. The curvature radius in cross section of the guide surface continuously changes in a cubic curve or a sine half-wavelength gradual decreasing curve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention comprises a guide body formed along the chain traveling direction, and a guide surface that slides in contact with the chain on the chain side of the guide body, and guides the chain in a sliding contact state or tensions in the sliding contact state. More particularly, the present invention relates to an improvement of a guide surface that is in sliding contact with a chain in the chain guide.

  Conventionally, in a guide for a chain provided with a guide main body formed along the chain traveling direction and a guide surface that slides into contact with the chain on the chain side of the guide main body, the guide guide of the chain can be smoothly moved into and out of the guide surface. As a shape of the guide surface for this purpose, there is known a shape in which the radius of curvature of the cross section of the guide surface in the vicinity of the chain entering and leaving portions is reduced.

  In an example of the timing system 500 used for driving a valve gear of an internal combustion engine, as shown in FIG. 5, the slack of the slack side span of the timing chain 501 is generated in order to generate an appropriate tension in the timing chain 501. A chain tensioner arm 510, which is a movable chain guide, is disposed with the tensioner 515, and a fixed guide 520, which is a chain guide fixed to the tension side span of the timing chain 501, in order to guide the travel of the timing chain 501. Is arranged.

  As shown in FIG. 6, the guide surfaces 511 and 521 of the chain tensioner arm 510 and the fixed guide 520 are arcuate (or substantially linear) first surfaces 512 and 522 having a large curvature radius, Arc-shaped second surfaces 513 and 523 formed at both ends and having a small radius of curvature r for smoothly connecting the first surfaces 512 and 522 to the respective ends of the chain tensioner arm 510 or the fixed guide 520. When the chain 501 travels on the guide surfaces 511 and 521 of the chain tensioner arm 510 or the fixed guide 520 during operation, the chain 501 first has the second surfaces 513 of the guide surfaces 511 and 521. 523, and after traveling on the first surfaces 512, 522 of the guide surfaces 511, 521, the guide surface 5 Through the second surface 513, 523 disposed on the second surface 513, 523 and opposite side of the 1,521, disengaged from the guide surface 511, 521.

  In the case of such a structure, the chain 501 strongly contacts the boundary portions 514 and 524 between the first surfaces 512 and 522 of the guide surfaces 511 and 521 and the second surfaces 513 and 523 at both ends thereof, and has a radius of curvature. Due to the sudden change, the reaction force is suddenly changed, the friction loss of the timing system 500 is increased, the boundary portions 514 and 524 are significantly worn, and an excessive load is applied to the chain 501. was there.

  In order to cope with such a problem, a connecting surface made of a clothoid curve is inserted at the boundary between the first surface and the second surface at both ends thereof, and the radius of curvature is continuously changed on the connecting surface. Chain guides are known. (For example, refer to Patent Document 1).

  As shown in FIG. 7, the guide surface of the chain guide is formed on a substantially linear or arc-shaped first surface 612 extending over most of the guide surface, and on the entry side of the chain 601. The first surface 612 and the second surface 613 are disposed between the first surface 612 and the second surface 613, and the second surface 613 having an arc shape smaller than the curvature radius of the first surface 612. It is comprised from the connection surface 614 which consists of a clothoid curve which connects the surface 613 of this.

  In the chain guide configured as described above, when the chain 600 travels on the guide surface of the chain guide, the chain 601 first enters the second surface 613 on the guide surface and then connects. After passing over the surface 614, the vehicle runs on the first surface 612 of the guide surface, and then passes through the second surface 613 (not shown) disposed on the opposite side of the guide surface and from above the guide surface. break away.

As described above, when the chain 601 enters the guide surface, the chain 601 passes over the connection surface 614 formed of a clothoid curve, so that the chain 601 can smoothly enter the guide surface and reduce the above problem.
JP 2007-64369 A (pages 5 to 7, FIG. 2)

  However, the guide surface of such a conventional chain guide is a short section where the connecting surface formed by a clothoid curve is only a boundary portion between the first surface and the second surfaces at both ends thereof, and the curvature is short in the short section. Since the radius changes rapidly, the above problems are alleviated to some extent, but there are still problems such as increased friction loss, significant wear on the boundary, and excessive load on the chain. There is a problem that the above-described problem becomes more difficult to relieve when the chain entry position or the separation position moves to the guide surface due to swinging accompanying the elongation of the chain or changing the position setting of the guide for the chain.

  Furthermore, since the curvature radius change rate changes abruptly at the connection point between the clothoid curve and the first surface and the second surface (the clothoid curve does not have a curvature radius change rate of zero), A sudden change in the reaction force is unavoidable, and there is a problem that the connection point is significantly worn or an excessive load is applied to the chain, and the change in radius of curvature of the clothoid curve is simply inversely proportional to the travel distance of the chain. Therefore, the part with a large radius of curvature will change more than necessary. Especially when the chain runs at high speed, it will give an excessive load to the chain even at the clothoid curve part and give a large surface pressure to the chain guide. There was a problem.

  The present invention solves the problems of the prior art as described above, that is, the object of the present invention is that there is little friction loss even when the chain runs at high speed, and there is no boundary portion that wears significantly. Further, it is an object of the present invention to provide a chain guide that does not impose an excessive load on the chain or apply a large surface pressure to the chain guide, and does not matter where the chain enters or leaves the guide surface.

  The invention according to claim 1 is a guide for a chain provided with a guide body formed along the chain traveling direction, and a guide surface that is in sliding contact with the chain on the chain side of the guide body. The above-mentioned problem is solved by being configured to be convex on the chain side and to have a sectional curvature radius continuously changing using a cubic curve or a sine half-wavelength decreasing curve.

  In addition to the structure of the chain guide described in claim 1, the invention according to claim 2 is characterized in that the guide surface has a cross-sectional curvature over the entire region from the entry to the release where the guide surface slides into contact with the chain and the extended portion thereof. By configuring the radius to change continuously, the above-described problem is further solved.

  In the invention according to claim 3, in addition to the structure of the chain guide described in claim 1 or 2, the guide surface is directed from one end side in the longitudinal direction of the guide surface to the other end portion. Thus, the above-mentioned problem is further solved by the configuration in which the radius of curvature of the cross section is continuously reduced.

  In the invention according to claim 4, in addition to the structure of the chain guide described in claim 1 or 2, the guide surface has a minimum point at which the radius of curvature of the cross section becomes the smallest in the middle portion in the longitudinal direction. And the above-mentioned problem is further solved by the configuration in which the radius of curvature of the cross section continuously increases from the minimum point toward both ends.

  In the invention according to claim 5, in addition to the structure of the chain guide described in claim 1 or 2, the guide surface has a maximum point where the radius of curvature of the cross section becomes the largest in the middle portion in the longitudinal direction. And the above-mentioned problem is further solved by the configuration in which the radius of curvature of the section continuously decreases from the maximum point toward both ends.

  According to the sixth aspect of the present invention, in addition to the structure of the chain guide according to any one of the first to fifth aspects, the guide main body is rotatably supported at an end. The above-described problem is further solved by being configured in a lever shape that can swing on the chain side.

  According to the seventh aspect of the invention, in addition to the structure of the chain guide described in any one of the first to fifth aspects, the guide main body is fixedly supported. The problem is further solved.

  The chain guide of the invention according to claim 1 is a guide for a chain provided with a guide main body formed along the chain traveling direction, and a guide surface that is in sliding contact with the chain on the chain side of the guide main body. The guide surface is convex on the chain side and the radius of curvature of the cross section changes continuously using a cubic curve or a sine half-wavelength decreasing curve. Therefore, there is no frictional loss even when the chain runs at high speed, there is no significant wear boundary, and even a part with a very large radius of curvature can be smoothed by using a cubic curve or sine half-wavelength decreasing curve. Since it can be made continuous, an excessive load is not applied to the chain and a large surface pressure is not applied to the chain guide.

  The chain guide of the invention according to claim 2 has the effect that the guide for the chain according to claim 1 exerts the entire area from the entrance to the release where the guide surface is in sliding contact with the chain. Even if the chain entry / exit position changes due to changes in the position / posture of the chain guide or vibration of the chain, etc., it is configured so that the radius of curvature of the section changes continuously over the extended part. It is possible to guide smoothly at the portion where the radius of curvature of the cross section changes continuously.

  Further, in the chain guide of the invention according to claim 3, in addition to the effect of the chain guide according to claim 1 or claim 2, the guide surface is from one end side in the longitudinal direction of the guide surface. By being configured so that the cross-section curvature radius continuously decreases toward the other end, the cross-section curvature radius always changes continuously even if the chain entry position changes greatly at the other end. It can guide smoothly in the part.

  Further, the chain guide of the invention according to claim 4 has the effect that the guide for chain according to claim 1 or claim 2 has the effect that the guide surface has the largest radius of sectional curvature at the middle portion in the longitudinal direction. Even when the travel direction of the chain is greatly changed by having a minimum point that becomes smaller and the radius of curvature of the cross section continuously increases from the minimum point toward both ends, the surface pressure can be reduced. The change is smooth and the chain can be guided smoothly.

  Further, in the chain guide of the invention according to claim 5, in addition to the effect exhibited by the chain guide according to claim 1 or 2, the guide surface has a cross-sectional radius of curvature most at an intermediate portion in the longitudinal direction. Change in surface pressure when there is almost no change in the running direction of the chain by having a maximum point that increases and the cross-section radius of curvature continuously decreases from the maximum point toward both ends. Can smoothly guide the chain, and can guide smoothly at the part where the radius of curvature of the section is continuously changing with respect to subtle changes in the entry / exit position due to chain vibration etc. it can.

  Further, in the chain guide of the invention according to claim 6, in addition to the effect exhibited by the chain guide according to any one of claims 1 to 5, the guide main body can freely rotate the end portion. Since it can be swung following the extension of the chain, it is used as a chain tensioner arm that keeps the chain tension constant. be able to.

  Further, the chain guide of the invention according to claim 7 is such that the guide main body is fixedly supported in addition to the effect exerted by the chain guide according to any one of claims 1 to 5. Therefore, it can be used as a fixed guide that greatly changes the direction of the chain and prevents running vibration and the like.

  The chain guide according to the present invention is a chain guide provided with a guide main body formed along the chain traveling direction and a guide surface that slides in contact with the chain on the chain side of the guide main body. Convex part that is convex on the side and has a cross-sectional radius of curvature that changes continuously using a cubic curve or a sine half-wavelength decreasing curve. It does not give excessive load to the chain and does not give a large surface pressure to the guide for the chain, so that it can be used regardless of the position of the chain entering or leaving the guide surface. For example, the specific embodiment is not particularly limited.

That is, the guide surface of the chain guide of the present invention may be integral with the guide body, or may be separated and exchanged as a separate body.
As a specific material of the guide surface, it is preferable to use a material that has low sliding friction and high durability.

  In addition, the specific material of the guide body used in the present invention is preferably a highly rigid and lightweight material such as an aluminum alloy or a resin material. There may be.

Below, the guide for chains which is an example of the present invention is explained based on a drawing.
FIG. 1 is a side view of a chain guide according to a first embodiment of the present invention, FIG. 2 is a side view of a chain guide according to a second embodiment of the present invention, and FIG. FIG. 4 is a side view of a chain guide according to a third embodiment of the present invention. FIG.

  As shown in FIG. 1, the chain guide 110 according to the first embodiment of the present invention has a fulcrum 121 rotatably supported at one end portion, and is pressed by a tensioner at the other end portion. And is used as the above-described conventional chain tensioner arm 510 shown in FIG.

The guide surface 111 of the chain guide 110 has a radius of curvature of one end L1 on the fulcrum 121 side of rl1, a radius of curvature of the other end S1 on the side of the pressing surface 130 of rs1, and a radius of curvature of the intermediate portion M1 of rm1. Configured,
rl1>rm1> rs2
Therefore, the entire guide surface 111 from one end L1 to the other end S1 is configured so that the radius of curvature continuously changes using a cubic curve or a sine half-wavelength decreasing curve.
The respective centers of curvature are Ol1, Om1, and Os1.
Since the chain (not shown) travels along the guide surface 111 from the vicinity of one end L1 to the vicinity of the other end S1, it extends over the entire area from the entry to the removal in sliding contact with the chain and its extension. The cross-sectional curvature radius is configured to change continuously.

When chain elongation or the like occurs, the pressing surface 130 is pressed by a tensioner (not shown) and rotates upward in FIG.
At this time, the separation point (entrance point) of the chain on the other end S1 side is largely close to the other end S1, but since the radius of curvature rs1 of the end S1 is set small, the separation point (entrance) Point), and the entire guide surface 111 is configured to continuously change using a cubic curve or a sine half-wavelength decreasing curve. Even when entering and leaving, there is no boundary part that wears significantly in any part that is in sliding contact with the chain, and excessive load is applied to the chain or a large surface pressure is applied to the chain guide. Absent.

  As shown in FIG. 2, the chain guide 210 according to the second embodiment of the present invention has fixing portions 221 and 222 fixedly supported at both ends, and the above-described conventional example shown in FIG. The fixed guide 520 is used.

The guide surface 211 from one end S21 to the intermediate portion L2 of the guide 210 for the chain and the guide surface 212 from the other end S22 to the intermediate portion L2 have a radius of curvature of each intermediate portion L2 of rl2. The radius of curvature of the end S21 and the other end S21 is composed of rs21 and rs22,
rl2> rs21
rl2> rs22
Therefore, each of the guide surface 211 and the guide surface 212 is configured such that the radius of curvature continuously changes using a cubic curve or a sine half-wavelength decreasing curve, and has the same radius of curvature at the intermediate portion L2. Yes.
The respective centers of curvature are Os21, Ol2, and Os22.
The intermediate portion L2 may be just the center of the entire guide surface or may be close to one of the end portions, and rs21 and rs22 may be the same or one of them may be larger.
The chain (not shown) travels along the guide surfaces 211 and 212 from the vicinity of one end S21 to the vicinity of the other end S22. The section curvature radius is continuously changed over the portion.

  Since the chain guide 210 is fixedly supported, the detachment point (entrance point) of the chain changes slightly due to vibration or the like, but is substantially constant, and the radii of curvature rs21 of both ends S21, S22, Since rs22 is set to be small, there is almost no disturbance in the running of the chain at the departure point (entrance point) so that the guide surfaces 211 and 212 continuously change using a cubic curve or a sine half-wavelength decreasing curve. Because it is configured, there is no boundary part that wears significantly in any part from the entry to the removal that comes into sliding contact with the chain, and an excessive load is applied to the chain or a large surface pressure is applied to the chain guide. There is nothing.

  As shown in FIG. 4, the chain guide 310 according to the third embodiment of the present invention is used as a fixed guide for a portion that greatly changes the traveling direction of the chain. As shown in FIG. It has the fixing | fixed part 321,322,323 fixedly supported by the intermediate part.

The guide surface 311 from one end L31 of the chain guide 310 to the intermediate portion S3 and the guide surface 312 from the other end L32 to the intermediate portion S3 have a radius of curvature of each intermediate portion S3 of rs3, The radius of curvature of the end portion L31 and the other end portion L32 is composed of rl31 and rl32.
rs3 <rl31
rs3 <rl32
Therefore, each of the guide surface 311 and the guide surface 312 is configured such that the radius of curvature continuously changes using a cubic curve or a sine half-wavelength decreasing curve, and has the same radius of curvature in the intermediate portion S3. Yes.
The respective centers of curvature are Ol31, Os3, and Ol32.
The intermediate portion S3 may be just the center of the entire guide surface or close to one of the end portions, and rl31 and rl32 may be the same or one of them may be larger.
The chain 301 travels along the guide surfaces 311 and 312 from the vicinity of one end L31 to the vicinity of the other end l32. The radius is configured to change continuously.

  Since the chain guide 310 greatly changes the traveling direction of the chain, the radius of curvature rs3 of the intermediate portion S3 is set to be the smallest, and the surface pressure at the intermediate portion S3 is the largest, but the guide surfaces 311 and 312 are cubic curves. Or, since it is configured to change continuously using a sine half-wavelength decay curve, the change in surface pressure from entry to release is smooth, and in any part from entry to release that comes into sliding contact with the chain However, there is no boundary portion that is significantly worn, and an excessive load is not applied to the chain or a large surface pressure is not locally applied to the chain guide.

  Therefore, the chain guide of the present invention thus obtained has little friction loss even when the chain runs at a high speed, there is no boundary portion that wears significantly, and an excessive load is applied to the chain. The effect is enormous, such as applying no large surface pressure to the chain guide and regardless of the position of the chain entering or leaving the guide surface.

The side view of the guide for chains which is 1st Example of this invention. The side view of the guide for chains which is 2nd Example of this invention. The use form figure of the guide for chains which is a 3rd example of the present invention. The side view of the guide for chains which is 3rd Example of this invention. Explanatory drawing of the timing system in which the conventional guide for chains is used. Explanatory drawing of the conventional guide for chains. Explanatory drawing of the guide for chains which has the conventional clothoid curve.

Explanation of symbols

300,500 ... Timing system
301, 501, 601 ... Timing chain 110 510 ... Chain guide
(Chain tensioner arm)
210, 310, 520 ... Chain guide (fixed guide)
111, 211, 311, 511 ... guide surfaces 212, 312, 521 ... guide surfaces 115, 515 ... tensioners 121 ... fulcrums 221, 321 ... fixed points 222, 322 ... fixed points
323... Fixed point

Claims (7)

In a guide for a chain provided with a guide body formed along the chain traveling direction, and a guide surface that is in sliding contact with the chain on the chain side of the guide body,
A guide for a chain, characterized in that the guide surface is convex on the chain side and the cross-sectional radius of curvature continuously changes using a cubic curve or a sine half-wavelength decreasing curve.   2. The chain according to claim 1, wherein the guide surface is configured so that a cross-sectional radius of curvature continuously changes over an entire area from an entrance to an exit where the guide surface is in sliding contact with the chain and an extended portion thereof. For guide.   The said guide surface is comprised so that a cross-section curvature radius may become small continuously toward the other end part from the one end part side of the longitudinal direction of the said guide surface. Chain guide as described.   The guide surface has a minimum point where the radius of curvature of the cross section becomes the smallest at an intermediate portion in the longitudinal direction, and the cross section radius of curvature continuously increases from the minimum point toward both ends. The guide for a chain according to claim 1 or 2, characterized by the above.   The guide surface has a maximum point where the radius of curvature of the cross section becomes the largest at an intermediate portion in the longitudinal direction, and the cross section radius of curvature is continuously reduced from the maximum point toward both ends. The guide for a chain according to claim 1 or 2, characterized by the above.   6. The guide body according to claim 1, wherein an end portion of the guide body is rotatably supported and is configured to be a lever that can swing toward the chain side. 6. Chain guide.   The chain guide according to claim 1, wherein the guide body is fixedly supported.

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