JP2005308144A - Blade tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blade tensioner capable of reliably controlling the behavior of a chain. <P>SOLUTION: The blade tensioner comprises a blade shoe 2 having a chain slide face 2a curved like an arc, a blade spring 3 for applying the spring force to the chain via the blade shoe 2, a base member 4 having a pin 41 turnably supporting a base end part 21 of the blade shoe 2 and a slide face 42 slidably supporting a tip part 22 of the blade shoe 2 when the blade shoe 2 is deformed, and a resin-made fixing member 5 which is arranged so that the blade spring 3 of a lowest layer is abutted when the blade shoe 2 and the blade spring 3 are deformed to a side where the radius of curvature thereof is increased, and stops the deformation of the blade shoe 2 and the blade spring 3. <P>COPYRIGHT: (C)2006,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 oppose the chain tension only by the spring force of the blade spring. For this reason, when excessive chain tension acts during the resonance of the chain, the blade shoe and blade In some cases, the spring was pushed in easily, and the behavior of the chain could not be controlled sufficiently. As a result, vibration and noise were generated.

  Therefore, the present applicant has proposed a blade tensioner as disclosed in JP-A-2003-65404. This blade tensioner has an auxiliary leaf spring whose one end is fixed to the base member, and when the blade shoe and the blade spring are pushed in due to excessive chain tension, the lowermost blade spring becomes the auxiliary leaf spring. The movement of the blade shoe and the blade spring is regulated by abutting on the tip of the blade.

However, in this case, when the auxiliary leaf spring is deformed, the maximum bending moment is generated at the proximal end portion of the auxiliary leaf spring. Therefore, when excessive chain tension acts repeatedly, May cause damage. In this case, there is also a problem that a collision noise is generated every time the lowermost blade spring contacts the auxiliary leaf spring.
JP 2000-234656 A JP 2003-65404 A

  The problem to be solved by the present invention is to enable reliable control of chain behavior in a blade tensioner. Another object is to prevent the generation of abnormal noise such as collision noise during driving.

  The main feature of the present invention is that a fixing member is provided so as to abut against the lowermost blade spring when the blade shoe and the blade spring are deformed to stop the deformation of the lowermost blade spring.

  A blade tensioner according to a first aspect of the present invention is provided with a blade shoe having a chain sliding surface curved in an arc shape, and 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 slide that has a plurality of blade springs to be acted on and a support shaft that rotatably supports the base end of the blade shoe, and that supports the tip of the blade shoe in a slidable manner when the blade shoe is deformed. A base member that has a surface, and a blade shoe and blade spring that are provided so that the lowermost blade spring abuts when the blade shoe and blade spring are deformed to the side where the radius of curvature is increased. And a member.

  According to the first aspect of the present invention, when the blade shoe and the blade spring are deformed to the side where the radius of curvature is increased, a fixing member is provided to stop the blade spring from coming into contact with the lowermost blade spring. The movement of the blade spring and the blade shoe can be reliably controlled. In this case, since there is no deformation as in the conventional auxiliary leaf spring, there is no fear of damage due to the deformation.

  In the invention of claim 2, the fixing member is fixed to the base member. In the invention of claim 3, the fixing member is detachably provided on the base member. In the invention according to claim 4, the fixing member is provided, for example, in the engine block on the engine side.

  In the invention of claim 5, the fixing member is made of resin, elastomer or rubber. In this case, it is possible to prevent a large collision sound from being generated when the lowermost blade spring collides with the fixed member.

  In the invention of claim 6, the contact surface of the fixing member with the blade spring is covered with a resin, an elastomer material or a rubber material. In this case as well, as in the case of the fifth aspect of the invention, it is possible to prevent a loud collision sound from being generated when the lowermost blade spring collides with the fixed member.

In the invention of claim 7, when the radius of curvature at the maximum deformation in the lowermost layer of the blade spring and R _1, which the radius of curvature of the contact surface between the blade spring in a fixed member and R _2, R _1> R ₂ and The relationship R ₁ ≈R ₂ is established.

  In this case, when the blade spring is deformed, the lowermost blade spring comes into surface contact with the contact surface of the fixing member, so that the blade spring can be stably supported and the occurrence of collision noise can be suppressed.

  According to the blade tensioner according to the present invention, the behavior of the chain can be reliably 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 installed in a chain system, and FIG. 2 is pushed by the chain. FIG. 3 is a sectional view taken along line III-III in FIG. 1, and FIG. 4 is an enlarged view of a fixing member of the blade tensioner.

  As shown in FIG. 1, the blade tensioner 1 includes a blade shoe 2 having a chain sliding surface 2 a that is curved in an arc shape, and a blade shoe 2 that is stacked on the opposite side of the chain sliding surface 2 a of the blade shoe 2. Are mainly composed of a plurality of leaf springs 3 in the form of leaf springs for applying a spring force to a chain (not shown) via a base, and a base member 4 for supporting the blade shoe 2.

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

  A pin (support shaft) 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 supported so as to be rotatable around the pin 41.

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

  As shown in FIG. 3, the slide surface 42 has a flat, substantially V-shaped cross section, and the tip portion 22 of the blade shoe 2 has a cross section substantially along the slide surface 42 having such a substantially V-shaped cross section. It has a V-shaped contact surface 22b.

  A fixing member 5 is attached to the base member 4 at a predetermined interval from the lowermost blade spring 3. As shown in FIG. 4, the fixing member 5 is a substantially T-shaped member, and includes a pad portion 50 disposed above and a shaft portion 51 extending below the pad portion 50.

  The pad portion 50 has an abutment surface 50a against which the lowermost blade spring 3 abuts when the blade shoe 2 and the blade spring 3 are deformed to the side where the radius of curvature is increased. The pad portion 50 is attached to the base member 4 such that the contact surface 50a protrudes from the attachment surface 4a on the base member side by Δ (about 1 mm).

Here, when the maximum deformation of the lowermost blade spring 3, i.e. the radius of curvature of R ₁ in the time of deformation of the curvature radius is maximum, when the radius of curvature of the abutment surface 50a of the fixing member 5 and R _2, R _1> relationship _{R 2} and _{R 1} ≒ _{R 2} is established.

  The shaft portion 51 is inserted into a mounting hole 43 formed in the base member 4. A head 51 a having a diameter larger than that of the shaft portion 51 is provided at the tip of the shaft portion 51, thereby preventing the shaft portion 51 from falling off from the mounting hole 43. The shaft portion 51 is formed with a slit 51b extending in the axial direction from the tip of the head portion 51a to the vicinity of the pad portion 50. The shaft 51 and the head 51 a can be reduced in diameter by the slit 51 b, so that the shaft 51 can be attached to and detached from the mounting hole 43. The fixing member 5 may be fixed to the base member 4.

  The fixing member 5 is preferably a resin, elastomer, or rubber member, but may be configured by combining these materials. For example, the entire surface may be molded with resin, and the contact surface 50a of the pad portion 50 may be covered with an elastomer material or a rubber material.

  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.
During operation, a chain (not shown) slides on the chain sliding surface 2 a of the blade shoe 2, and at this time, a spring force according to the deformation of the blade spring 3 is passed through the blade shoe 2 through the chain. By acting on the chain tension, the chain tension is maintained. At this time, in accordance with the deformation of the blade shoe 2, the contact surface 22 b of the blade shoe distal end portion 22 moves while sliding on the slide surface 42 having a substantially V-shaped cross section.

  Next, when excessive tension is generated in the chain due to resonance of the chain and an excessive pressing force acts on the blade shoe 2 from the chain, the blade shoe 2 and the blade spring 3 are moved to the side where the radius of curvature becomes large. Deform. At this time, the lowermost blade spring 3 contacts the contact surface 50a of the pad portion 50 of the fixing member 5 (see FIG. 2). Thereby, further deformation of the blade shoe 2 and the blade spring 3 is stopped. In this way, the movement of the blade spring 3 and the blade shoe 2 can be reliably controlled. In this case, since there is no deformation as in the conventional auxiliary leaf spring, there is no fear of damage due to the deformation.

  In this case, since the fixing member 5 is made of resin, elastomer, or rubber, it is possible to prevent a large collision sound from being generated when the lowermost blade spring 3 collides with the fixing member 5.

Further, in this case, as described above, since the relationship of R ₁ > R ₂ and R ₁ ≈R ₂ is established, when the blade spring 3 is deformed, the lowermost blade spring 3 is attached to the fixing member 5. As a result, the blade spring 3 can be stably supported and, at the same time, the occurrence of collision noise can be suppressed.

  In the above embodiment, the blade tensioner unitized with the base member has been described as an example. However, the present invention is not unitized with the base member, that is, the blade shoe is attached to the engine side component corresponding to the base member. The blade tensioner may be configured to be attached to the blade tensioner. In this case, the fixing member is also attached to an engine side component, for example, an engine block.

  The blade tensioner according to the present invention is particularly suitable for a timing chain of an automobile engine, but may be applied to an accessory driving chain such as an oil pump.

It is a front view of the blade tensioner of the installation state by one Example of this invention. FIG. 2 is a front view of the blade tensioner of FIG. 1 in a state where a blade spring is pushed from a chain. It is the III-III sectional view taken on the line of FIG. It is an enlarged view of the fixing member in the blade tensioner of FIG.

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 surface

5: Fixing member 50a: Contact surface

Claims (7)

A blade tensioner for applying tension to the chain,
A blade shoe having a chain sliding surface curved in an arc;
A plurality of blade springs in the form of leaf springs disposed on the opposite side of the chain 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 surface that slidably supports a tip portion of the blade shoe when the blade shoe is deformed;
A fixing member for stopping the deformation of the blade shoe and the blade spring provided so that the lowermost blade spring contacts when the blade shoe and the blade spring are deformed to the side where the radius of curvature is increased; ,
Blade tensioner with In claim 1,
The fixing member is fixed to the base member;
Blade tensioner characterized by that. In claim 2,
The fixing member is detachably provided on the base member;
Blade tensioner characterized by that. In claim 1,
The fixing member is provided on the engine side;
Blade tensioner characterized by that. In claim 1,
The fixing member is made of resin, elastomer or rubber,
Blade tensioner characterized by that. In claim 1,
The contact surface of the fixing member with the blade spring is covered with a resin, an elastomer material, or a rubber material,
Blade tensioner characterized by that. In claim 1,
The radius of curvature at the maximum deformation in the lowermost layer of the blade spring and R _1, the curvature radius of the contact surface of the blade spring in the fixing member when the R _2,
R ₁ > R ₂ and R ₁ ≈R ₂
The relationship is established,
Blade tensioner characterized by that.

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