JP4890480B2 - Manufacturing method of tensioner lever - Google Patents

Description

  The present invention relates to a method of manufacturing a tensioner lever that always applies an appropriate tension force to a chain wound around a sprocket of a drive shaft and a driven shaft. The tensioner lever is not limited to a tensioner lever in a narrow sense that directly applies tension to the chain by the tensioner, but includes a chain guide and a chain damper disposed on the opposite side of the chain. A member that applies force is defined as a tensioner lever.

  FIG. 7 shows a general chain drive device. The chain (A) is wound around a sprocket (d) and (e) attached to a drive shaft (b) and a driven shaft (c). The chain (A) is pressed by the tensioner lever (F), and an appropriate tension is constantly applied. Accordingly, the vibration of the chain (A) traveling along with the rotation of both sprockets (D) and (E) is suppressed, and transmitted to the driven shaft (C) without causing a time delay. Further, by suppressing the vibration, the impact force acting on the chain (A) is eliminated, and the chain life can be improved.

  By the way, the tensioner lever (f) is pressed by the tensioner (g) and acts on the chain (b). There are various forms of the tensioner lever (f), and generally a metal arm is made of rubber. Alternatively, a resin shoe is bonded, or the shoe is formed integrally with the arm. When the shoe is bonded to the arm, it may be peeled off, and when the shoe is integrally formed with the arm, a molding die is required and the manufacturing cost becomes high.

  Therefore, a tensioner lever in which separately manufactured arms and shoes are assembled and fixed without using an adhesive is known. The “chain guide rail provided with a synthetic resin shoe” according to Patent Document 1 has a structure in which a shoe is detachably attached to a shoe support member. That is, the end hook piece formed on the shoe is engaged with the chain running start end of the shoe support member, and the L-shaped side engagement piece formed on the shoe is engaged with and attached to the shoe support member. Yes.

  As described above, the shoe is attached to the shoe support member (arm) in a detachable state, and various other attachment structures of the shoe are known. For example, the “tensioner lever shoe lift prevention structure” according to Patent Document 2 is one of the shoes that is attached in a detachable structure.

  By the way, the arm of the conventional tensioner lever is often die-cast using an aluminum alloy. However, in order to achieve both strength and weight reduction, it is considered suitable to make the arm cross section I-type. (See Patent Document 3). FIG. 8 shows a state in which a shoe (b) is attached to the outer periphery of an arm (b) having an I-shaped cross section.

  The arm (A) having the I-shaped cross section is formed by die-casting using a pair of split molds. In FIG. 9, the arm (I) is formed by split molds (C) and (C). It is in the state. The arm (A) die-cast on the I-shaped section is taken out by opening the split molds (C) and (C), but the arm (I) and the split molds (C) and (C) are easily separated. A draft angle is provided. That is, when the split molds (C) and (C) are opened after molding, even if the arm (I) remains in one split mold (C), the arm (A) is removed by having a draft angle. I can do it. On the contrary, if there is no draft, it is not easy to remove the arm (b) from the split mold (c).

  As shown in FIG. 10, the I-shaped cross-section arm removed from the split molds (C) and (C) has a draft angle in the split molds (C) and (C), so that the upper end surface is neutral. Tapered surfaces (d), (d) ... inclined to both sides. Since the shoe (b) cannot be attached to the tapered surfaces (d) and (d), the tapered part (shaded part in FIG. 10) at the upper end of the arm is removed by cutting. The upper end of the arm must be smoothly curved and machined in the longitudinal direction so that a shoe (b) can be attached, and the machining of the tapered portion requires a large number of processing steps.

No. 7-36201 Utility Model Registration No. 2519476 Japanese Utility Model Publication No. 4-119654

  As described above, the arm constituting the tensioner lever has the above-described problems. The problems to be solved by the present invention are these problems, and an object thereof is to provide a method for manufacturing a tensioner lever that does not require secondary processing after die casting.

The present invention provides an outer peripheral piece (8), an inner peripheral piece (9), a rib provided obliquely across one end in the width direction of the inner peripheral piece (9) and the other end in the width direction of the outer peripheral piece (8). (10) and an arm (1) having a Z-shaped cross section ,
A tensioner lever manufacturing method comprising: a shoe (2) attached to the outer peripheral piece (8) of the arm;
The arm (1) is formed by aluminum die casting comprising split molds (11a) and (11b), and the split mold has a parting line (P1) in a closed state so that the width of the outer peripheral piece (8) It is configured to extend from the one end side surface (8a) in the direction toward the side opposite to the inner peripheral piece (9) ,
The outer peripheral surface (12) of the outer peripheral piece (8) is molded by the cabin of one split mold (11b) so that there is no tapered surface as a draft angle,
Becomes attached detachably to said shoe (2) to the outer peripheral piece of the arm which is formed (1) (8) by the aluminum die casting,
The present invention resides in a method for manufacturing a tensioner lever.

The split type parting line in the closed state (P2) is, the outer peripheral piece from the other widthwise end side surface of the inner peripheral piece (9) (9a) and (8) extending toward the opposite side Composed of
The inner peripheral surface (13) of the inner peripheral piece (9) is formed by the cabin of the other split mold (11a) , and the outer peripheral surface ( 8) of the outer peripheral piece (8) has no tapered surface as a draft. 12).

  The above-mentioned arm is die-cast and the mold to be used is a split mold that forms a pair, but no draft is provided in the split mold. That is, the outer peripheral surface (12) of the outer peripheral piece (8) is formed by the cabin of one split mold (11b), and preferably, the inner peripheral surface (13) of the inner peripheral piece (9) is the other split mold (11a). Therefore, the arm formed without the draft can be easily removed from the split mold. Therefore, there is no taper surface on the outer peripheral surface of the arm, and it is not necessary to cut and remove by secondary processing.

  By the way, a shoe molded using a material such as rubber or resin is attached along the outer peripheral surface of the arm. The mounting structure of the shoe can be easily attached to and detached from the arm, and can be displaced. I am trying not to. However, the specific structure of installation is not limited. Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

  The arm of the tensioner lever of the present invention is formed by aluminum die casting, and the split parting line at that time passes through one end side surface in the width direction of the outer peripheral piece, and the outer peripheral surface of the outer peripheral piece is one split mold. Can be die-cast using a split mold that does not have a draft angle, so there is no need for secondary machining of the outer surface of the arm to which the shoe is attached, reducing the man-hours for arm production. Is done. The shoe of the lever is attached to the outer peripheral surface of the arm, but is detachable and can be easily replaced if it is damaged by wear or the like.

The split mold parting line, so as to extend from the other widthwise end side surface of the inner peripheral piece, the inner peripheral surface of the inner peripheral piece is molded by the other split mold cabin, also the inner circumferential surface, It can be formed with a surface parallel to the outer peripheral surface of the outer peripheral piece without a tapered surface as a draft.

  In addition, the rib of the arm is provided obliquely across the other end in the width direction of the outer peripheral piece and one end in the width direction of the inner peripheral piece, and the above-mentioned arm has a Z-shaped cross section. Even if the arm remains in the mold, the arm can be easily removed from the other split mold.

  FIG. 1 shows an embodiment of a tensioner lever according to the present invention. The tensioner lever is composed of a curved arm 1 and a shoe 2, and the shoe 2 is attached to the outer periphery of the arm 1 so that the shoe 2 can be removed if the shoe 2 is damaged due to wear or the like. Yes. Here, the mounting structure of the shoe 2 is not limited, but in the tensioner lever shown in the figure, the keys 3 and 4 provided at both ends of the shoe 2 are the locking pieces 5 on the chain travel start end side of the arm 1. Are respectively locked to the locking pieces 6 on the opposite side. And the side part of the shoe 2 has L-shaped engagement pieces 7, 7... And engages with the side part of the arm 1.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. 1, and shows a specific example showing a cross section of the tensioner lever. As is clear from the figure, the cross section of the arm 1 is Z-shaped, and has an outer peripheral piece 8 and an inner peripheral piece 9 that are parallel to each other. It is connected. That is, the rib 10 extends obliquely across one end in the width direction of the inner peripheral piece 9 and the other end in the width direction of the outer peripheral piece.

  In the outer peripheral piece 8 and the inner peripheral piece 9, the base side to which the rib 10 is connected is thicker than the tip, and therefore the outer peripheral piece 8 and the inner peripheral piece 9 are independent compared to the case where the thickness is the same as the tip. The bending strength at is high. By the way, this arm 1 is die-cast using aluminum as a material, and a pair of split dies 11a and 11b are used as the molding die as shown in FIG.

In the split molds 11a and 11b, the cabin formed in a closed state has a Z-shaped cross section, but is not symmetrical with respect to the central axis, and the outer peripheral surface 12 is formed by the cabin of one split mold 11b. The inner peripheral surface 13 is formed by the cabin of the other split mold 11a. That is, the split mold 11a, the parting line P1-P2 and 11b are, in the closed state of the split mold, from the cabin from the widthwise end sides 8a and the width direction other end side 9a of the inner peripheral piece of the outer piece 8 They are formed in parallel to each other so as to extend in the directions away from each other. That is, the parting line P1 extending from the one end side surface 8a in the width direction of the outer peripheral piece 8 extends toward the side opposite to the inner peripheral piece 9, and the parting line P2 extending from the other end side surface 9a in the width direction of the inner peripheral piece 9 is It extends toward the side opposite to the outer peripheral piece 8. Therefore, the outer peripheral surface 12 and the inner peripheral surface 13 are free of burrs generated in the gap between the split molds 11a and 11b, and it is not necessary to provide a tapered surface as a draft angle.

  When an arm having a Z-shaped cross section is die casted with aluminum by the split molds 11a and 11b and then the split molds 11a and 11b are opened, even if the arm remains on one split mold 11b side, Since the split mold 11a is separated, the arm of the Z-shaped section is easily detached from the split mold 11b. The ribs 10 connecting the outer peripheral piece 8 and the inner peripheral piece 9 are not continuous over the entire length, and through holes can be provided in some places. It is possible to cast.

  By the way, the most required strength of the arm 1 is bending strength, and the force from the chain running on the shoe 2 acts on the tensioner lever that swings about the shaft that fits in the shaft hole 14 in FIG. Balance with the tensioner that presses the arm 1. Therefore, a large bending stress acts on the arm 1 and a strength that can withstand this stress is required.

  FIG. 4 is a cross-sectional moment of comparison between the conventional I-shaped section and the Z-shaped section according to the present invention. The height H, the distance h between the outer peripheral piece and the inner peripheral piece, the width T, the rib thickness in the arm cross section of both. In the case of t, the cross-sectional secondary moments of both are equal, and therefore the bending strength is also equal. The bending strength is not reduced by making the arm cross section Z-shaped.

  FIG. 5 shows a tensioner lever to which the shoe 2 is attached with another mounting structure. Therefore, the back surface of the shoe 2 is in contact with the outer peripheral surface 12 of the arm, and in this case, the protrusion 15 at the chain running start end fits into the groove, and the L-shaped engagement pieces 16, 16. The protrusions are engaged with holes formed on the outer peripheral surface of the arm.

  FIG. 6 shows an enlarged cross-sectional view taken along the line BB in FIG. (C) shows the case where the shoe 2 is attached to the arm 1, (a) shows the case where the shoe 2 is removed, and (b) shows the case where the shoe 2 is attached to the arm 1. A protrusion 18 protrudes from the back surface 17 of the shoe 2, and the cross-section of the protrusion 18 forms a right triangle, and the side on which the L-shaped engagement piece 16 is formed rises vertically from the back surface 17. It is a surface 19. The protruding piece 18 is fitted into a hole 20 formed in the outer peripheral surface 12 of the arm 1, but the locking surface 19 is in contact with the inner surface of the hole 20 and the protruding piece 18 can be locked. .

  When the shoe 2 is removed from the arm 1, if the sharpened piece 18 is removed from the hole 20 by inserting a pointed tool on the opposite side of the L-shaped engagement piece 16, the entire shoe 2 is L-shaped. Move to the side of the engagement piece and disengage. On the contrary, when attaching the shoe 2 to the arm 1, as shown in (b), the L-shaped engagement pieces 16, 16... Are fitted into the notch grooves (not shown) formed on the side surface of the arm 1, If pressing is performed in the direction of the arrow in this state, the protrusion 18 can be fitted into the hole 20. In this case, the protrusion 15 at the chain running start end is also fitted in the groove.

  By engaging the L-shaped engagement piece provided on the shoe with the notch groove of the arm and inserting and locking the protruding piece into the hole, the shoe does not come off from the arm and floats from the arm I don't have to. Of course, the shoe cannot move sideways.

The front view which shows the tensioner lever by the Example of this invention. FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. 1. Sectional drawing which shows the split type which die-casts the arm of this invention. Sectional drawing for comparing the cross-sectional secondary moment of the arm of the Z-shaped section which concerns on this invention, and the arm of the conventional I-shaped section. The front view which shows the other Example which shows the tensioner lever of this invention. FIG. 6 is an enlarged cross-sectional view taken along the line BB in FIG. The front view which shows the chain transmission apparatus provided with the tensioner apparatus. Sectional drawing which shows the conventional tensioner lever. Sectional drawing which shows the split mold which carries out the die-cast shaping | molding of the arm of an I type cross section. Sectional drawing of the arm which has a taper surface formed in the arm outer periphery of an I type cross section.

Explanation of symbols

1 Arm 2 Shoe 8 Outer peripheral piece 8a Width direction one end side surface 9 Inner peripheral piece 9a Width direction other end side surface 10 Rib 11 Split mold 11a The other split mold 11b One split mold 12 Outer peripheral face 13 Inner peripheral face P1-P2 Parting line

Claims (2)

An arm composed of a Z-shaped cross section having an outer peripheral piece, an inner peripheral piece, and a rib provided obliquely across one end in the width direction of the inner peripheral piece and the other end in the width direction of the outer peripheral piece ;
A tensioner lever manufacturing method comprising: a shoe attached to the outer peripheral piece of the arm;
The arm is formed by an aluminum die cast made of a split mold, and in the split mold, a parting line in a closed state extends from one end side surface in the width direction of the outer peripheral piece toward the side opposite to the inner peripheral piece. Configured as
The outer peripheral surface of the outer peripheral piece is molded so as not to have a tapered surface as a draft by one split mold cabin,
It becomes attached to the shoe detachably to the outer peripheral piece of the arm molded by the die-cast aluminum,
A method of manufacturing a tensioner lever characterized by the above. The split type parting line in the closed state, is composed of the other widthwise end side surface of the inner peripheral piece so as to extend toward the side opposite to the outer peripheral piece,
The inner peripheral surface of the inner peripheral piece is formed by the other split mold cabin, and is formed by a surface parallel to the outer peripheral surface of the outer peripheral piece without a tapered surface as a draft angle.
The manufacturing method of the tensioner lever of Claim 1.

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