JP2005155795A - Blade tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blade tensioner for sufficiently controlling the behavior of a chain. <P>SOLUTION: The blade tensioner comprises a blade shoe 2 having a chain sliding face 2a, a blade spring 3 for giving springing force to the chain 10, and a base member 4 having a pin 41 for turnably supporting the blade shoe 2 at its base end 21 and a sliding portion 42 for slidably supporting the blade shoe 2 at its front end 22. At an extension end 42A of the sliding portion 42 of the base member 4, a ratchet mechanism 6 is provided for restricting the deformation of the blade shoe 2 to the side of increasing its radius of curvature and for allowing the deformation to the side of reducing the radius of curvature. The ratchet mechanism 6 has a lock portion 60 to be locked to the extension end 42A of the sliding portion 42, a first arm portion 64 whose front end 64a abuts on the blade spring 3 and which has rack teeth 64b formed on the back side, and a second arm portion 65 for engaging with the rack teeth 64b of the first arm portion 64. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a blade tensioner including a blade shoe having a chain sliding surface and a leaf spring-like blade spring that applies a spring force to the blade shoe.

  In an automobile engine, a blade tensioner is used as a tensioner for applying tension to an accessory driving chain such as a timing chain or an oil pump.

  As shown in Japanese Patent Application Laid-Open No. 2000-234656, a conventional blade tensioner is arranged by laminating a blade shoe having a chain sliding surface curved in an arc shape on the opposite side of the chain sliding surface of the blade shoe. Via a plurality of leaf springs for applying spring force to the chain, and a support shaft that rotatably supports the base end of the blade shoe. The tip of the blade shoe is slidable. And a base member having a slide surface to be supported.

  During chain operation, the chain runs while sliding on the chain sliding surface of the blade shoe. At this time, the spring force accompanying the elastic deformation of the blade spring acts on the chain as a pressing load, maintaining the chain tension. It has come to be. In addition, when the chain tension fluctuates during operation, the tip of the blade shoe slides on the slide surface and the base end rotates around the support shaft so that the blade shoe and the blade spring The radius of curvature changes, and a spring force corresponding to the deformation acts on the chain.

However, the conventional blade tensioner is configured to resist the chain tension only by the spring force of the blade spring, and therefore, when the chain tension is excessive, the behavior of the chain cannot be sufficiently controlled. There was a case. As a result, vibration and noise were generated.
JP 2000-234656 A

  The problem to be solved by the present invention is to make it possible to sufficiently control the chain behavior in a blade tensioner.

  The main feature of the present invention is that a ratchet mechanism is provided at the extended end of the slide portion of the base member.

  A blade tensioner according to a first aspect of the present invention includes a blade shoe having a chain sliding surface that is curved in an arc shape, and a blade shoe that is disposed on the opposite side of the chain sliding surface of the blade shoe, and applies a spring force to the chain via the blade shoe. A plate spring-like blade spring for supporting the blade shoe and a support shaft portion that rotatably supports the base end portion of the blade shoe, and a slide portion that slidably supports the tip portion of the blade shoe when the blade shoe is deformed. And a base member. The base member is provided with a ratchet mechanism that restricts deformation of the blade shoe to the side where the curvature radius is increased and allows deformation to the side where the curvature radius is decreased.

  According to the first aspect of the present invention, when a pressing load is applied from the chain to the blade shoe, the blade shoe tends to deform toward the side where the radius of curvature of the blade shoe becomes larger. At this time, the extension of the slide portion of the base member A ratchet mechanism provided at the end regulates such deformation of the blade shoe. As a result, even when excessive tension is applied from the chain, the chain tension can be counteracted and the behavior of the chain during operation can be sufficiently controlled.

  On the other hand, when slack occurs in the chain, the blade shoe tends to be deformed toward the side where the radius of curvature of the blade shoe becomes smaller. At this time, the ratchet mechanism allows such deformation of the blade shoe. Thereby, it becomes possible to follow the movement of the chain.

  In the invention of claim 2, the ratchet mechanism has an upper plate portion, a lower plate portion formed by bending a belt-like thin plate member into a U-shape, and a connecting plate portion for connecting them, and an extended end of the slide portion. A locking portion that is locked to the upper plate portion, and an oblique angle extending upward from one end of the upper plate portion of the locking portion with respect to the upper plate portion. The first arm portion is formed and a part of the upper plate portion is cut away, and the first arm portion extends in a direction intersecting the first arm portion while forming an acute angle with respect to the upper plate portion. And a second arm portion that engages with the rack teeth of the arm portion.

  In the invention of claim 3, the ratchet mechanism has an upper plate portion, a lower plate portion formed by bending a belt-like thin plate member into a U-shape, and a connecting plate portion connecting them, and an extended end of the slide portion And is formed by cutting out a part of the upper plate portion, extending obliquely upward while forming an acute angle with respect to the upper plate portion, the tip contacting the blade spring, and the back side The first arm portion formed with rack teeth on the top and the one end of the upper plate portion of the locking portion extend in a direction intersecting the first arm portion while forming an acute angle with respect to the upper plate portion, and the first arm portion It is comprised from the 2nd arm part engaged with the rack tooth of an arm part.

  According to the blade tensioner according to the present invention, since the ratchet mechanism is provided at the extended end of the slide portion of the base member, the behavior of the chain during operation can be sufficiently controlled.

  1 to 4 are views for explaining a blade tensioner according to an embodiment of the present invention. FIG. 1 is a front view of the blade tensioner in an initial state set in a chain system, and FIG. FIG. 3 is a perspective view of the ratchet mechanism as viewed from above, and FIG. 4 is a perspective view of the ratchet mechanism as viewed from below.

  As shown in FIGS. 1 and 2, the blade tensioner 1 includes a blade shoe 2 having a chain sliding surface 2 a curved in an arc shape, and a laminated arrangement on the opposite side of the chain sliding surface 2 a of the blade shoe 2. It is mainly composed of a plurality of leaf springs 3 each having a plate spring shape for applying a spring force to the chain 10 via the blade shoe 2 and a base member 4 for supporting the blade shoe 2.

  Grooves 21a and 22a are formed at both ends of the blade shoe 2, and the end portions of the blade spring 3 are inserted into the grooves 21a and 22a and locked.

  A pin (support shaft portion) 41 fixed to the base member 4 is inserted into the base end portion 21 of the blade shoe 2, and the base end portion 21 is rotatable around the pin 41. A washer 5 for preventing the base end 41 from coming off is fixed to the tip of the pin 41.

  The tip portion 22 of the blade shoe 2 is slidably supported on a flat slide surface 42 a in a slide portion 42 provided on the base member 4. The tip 22 of the blade shoe 2 is always in contact with the slide surface 42a so as to slide on the slide surface 42a when the blade shoe 2 is deformed according to the pressing load from the chain 10.

  The slide portion 42 of the base member 4 extends toward the pin 41, and the ratchet mechanism 6 is provided at the extended end 42A. As shown in FIGS. 3 and 4, the ratchet mechanism 6 has a locking portion 60 formed by bending a belt-like thin plate member into a U shape. The locking portion 60 includes an upper plate portion 61 and a lower plate portion 62 that are arranged to face each other at a predetermined interval, and a connecting plate portion 63 that connects them, and the upper plate portion 61 and the lower plate portion 62. By holding the extended end 42A of the slide portion 42 from above and below, the locking portion 60 can be detachably engaged with the extended end 42A of the slide portion 42.

  The ratchet mechanism 6 includes a first arm portion 64 that is formed integrally with the upper plate portion 61 of the locking portion 60 and extends obliquely upward while forming an acute angle with the upper plate portion 61. The distal end 64a of the first arm portion 64 can come into contact with the lower surface of the lowermost blade spring 3. Rack teeth 64b are formed on a portion of the first arm portion 64 on the back side. The upper plate portion 61 is partly cut out, extends in a direction intersecting the first arm portion 64 while forming an acute angle with respect to the upper plate portion 61, and a tip 65 a of the first arm portion 64. It has the 2nd arm part 65 engaged with the rack tooth | gear 64b.

  The ratchet mechanism 6 regulates downward deformation of the first arm portion 64, that is, bending deformation (for example, deformation from FIG. 2 to FIG. 1) toward the side where the radius of curvature of the blade shoe 2 increases, and the first The arm portion 64 is provided so as to allow upward return deformation, that is, deformation toward the side where the radius of curvature decreases (for example, deformation from FIG. 1 to FIG. 2).

  The base member 4 has a plurality of mounting holes 43 into which mounting bolts (not shown) are inserted.

Next, the operation of the blade tensioner configured as described above will be described.
In the state shown in FIG. 1 or 2, when a pressing load is applied from the chain 10 to the blade shoe 2, the blade shoe 2 tends to be deformed to the side where the radius of curvature becomes larger. The tip 64 a of the first arm member 64 is in contact with the lower surface of the lower blade spring 3, and the tip 65 a of the second arm member 65 is locked to the rack teeth 64 b on the back side of the first arm member 64. Therefore, deformation of the blade shoe 2 is suppressed.

  When the pressing load from the chain 10 is applied to the blade spring 3 via the blade shoe 2, the portion preceding the second arm member locking portion of the first arm member 64 tends to be deformed. The amount of deformation is slight. As a result, even when excessive tension is applied from the chain, the chain tension can be counteracted and the behavior of the chain during operation can be sufficiently controlled.

  On the other hand, when the chain 10 is slack, the blade shoe 2 tends to be deformed toward the side where the radius of curvature of the blade shoe 2 becomes smaller. At this time, the ratchet mechanism 6 causes the deformation of the blade shoe 2. Is allowed. As a result, the blade shoe 2 can follow the movement of the chain.

  In the above-described embodiment, the first arm member 64 is in contact with the blade spring 3. However, the present invention reverses the positional relationship between the first and second arm members 64 and 65. It can be applied to the same as above.

  That is, in this case, rack teeth are formed on the back side of the second arm member 65 so that the tip 65a of the second arm member 65 is brought into contact with the blade spring 3, and the first arm member The tip 64 a of 64 is engaged with the rack teeth of the second arm member 65. In this case as well, as in the above-described embodiment, it is possible to counter an excessive chain tension and to sufficiently control the behavior of the chain.

It is a front view of the initial state of a blade tensioner according to an embodiment of the present invention. FIG. 2 is a front view of the blade tensioner of FIG. 1 in a state where the chain is slack. It is the perspective view which looked at the ratchet mechanism part of the blade tensioner from the upper part. It is the perspective view which looked at the ratchet mechanism part of the blade tensioner from the lower part.

Explanation of symbols

1: Blade tensioner

2: Blade shoe 2a: Chain sliding surface 21: Base end 22: Tip

3: Blade spring

4: Base member 41: Pin (support shaft)
42: Slide part 42a: Slide surface 42A: Extension end

6: Ratchet mechanism 60: Locking portion 61: Upper plate portion 62: Lower plate portion 63: Connecting plate portion 64: First arm portion 64a: Tip 64b: Rack teeth 65: Second arm portion

10: Chain

Claims (3)

A blade tensioner for applying tension to the chain,
A blade shoe having a chain sliding surface curved in an arc;
A blade spring-like blade spring disposed on the opposite side of the blade sliding surface of the blade shoe to apply a spring force to the chain via the blade shoe;
A base member having a support shaft portion that rotatably supports a base end portion of the blade shoe, and a slide member that slidably supports a distal end portion of the blade shoe when the blade shoe is deformed,
The base member is provided with a ratchet mechanism that restricts deformation of the blade shoe to the side with a larger curvature radius and allows deformation to the side with a smaller curvature radius.
Blade tensioner characterized by that. In claim 1,
The ratchet mechanism is
An upper plate portion formed by bending a belt-like thin plate member into a U-shape, a lower plate portion, and a connecting plate portion connecting them, and a locking portion locked to an extended end of the slide portion;
First extending from one end of the upper plate portion of the locking portion obliquely upward with an acute angle with respect to the upper plate portion, the tip abutting against the blade spring, and rack teeth formed on the back side Arm part,
The rack of the first arm portion is formed by cutting out a part of the upper plate portion and extends in a direction intersecting the first arm portion while forming an acute angle with respect to the upper plate portion. A second arm portion that engages with the teeth;
Blade tensioner characterized by that. In claim 1,
The ratchet mechanism is
An upper plate portion formed by bending a belt-like thin plate member into a U-shape, a lower plate portion, and a connecting plate portion connecting them, and a locking portion locked to an extended end of the slide portion;
It is formed by cutting out a part of the upper plate part, extends obliquely upward while forming an acute angle with respect to the upper plate part, the tip abuts against the blade spring, and rack teeth are formed on the back side A first arm part;
The locking portion extends from one end of the upper plate portion in a direction intersecting the first arm portion while forming an acute angle with respect to the upper plate portion, and is engaged with the rack teeth of the first arm portion. A second arm portion that
Blade tensioner characterized by that.

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