JP2606244Y2 - Bicycle front gear - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle front gear having at least one large-diameter front gear and at least one small-diameter front gear, and more particularly to a front gear having a chain guard.

[0002]

2. Description of the Related Art Conventionally, a bicycle front gear is provided with a chain guard, as disclosed in Japanese Utility Model Publication No. 59-41916, for example, to prevent the chain from falling off from a large-diameter front gear during shifting. There was something like that.

[0003]

In the conventional front gear, the chain guard is formed by a single member over the entirety. Therefore, for example, when the chain touches the chain guard to prevent the chain from falling off,
To reduce noise and prevent chain damage,
When the chain guard is made of resin, it is necessary to increase the wall thickness or to make the shape advantageous in terms of strength in order to provide a predetermined guard strength irrespective of the resin, and it becomes heavy. The problem of becoming large was likely to occur. An object of the present invention is to prevent a chain from falling off while suppressing noise and damage to the chain, and furthermore, to make the bicycle easily durable, light and small and excellent in appearance. To provide a front gear.

[0004]

SUMMARY OF THE INVENTION In order to achieve the object, a bicycle front gear according to the present invention is characterized in that, in order to achieve the object, a guard action portion made of a resin for preventing the chain from falling off, and the guard action portion are provided. A chain guard that reinforces the guard action portion along with an annular reinforcing body formed separately from the guard action portion and connected to the guard action portion, Place it on the side outside,
The working end of the guard action portion is disposed closer to the large-diameter front gear than the annular reinforcement in a state of contacting the chain in preference to the annular reinforcement, and the guard action portion and the annular reinforcement are disposed. A plurality of connected resin connecting members are integrally formed on the guard acting portion and are dispersed and arranged in the circumferential direction of the annular reinforcing member. The chain guard is separated from the large-diameter front gear and the crank. The large-diameter front gear is connected to the large-diameter front gear via a mounting arm formed as a body, and a mounting portion for the large-diameter sprocket is provided on the mounting arm.

[0005]

[Action] When the chain comes off the large-diameter front gear,
The guard action part hits the chain and supports it so that it does not fall from the gear. At this time, since the guard acting portion is made of resin, the chain and the guard acting portion come into contact with each other in a state where the contact sound is less likely to be generated and the chain is not easily damaged as compared with the case where the guard acting portion is made of metal. In other words, when the chain is prevented from falling off, the guard action portion made of resin comes into contact with the chain preferentially to the reinforcing member, making it difficult for sound to come out and for the chain to be easily damaged. Further, in preparing the chain guard, a reinforcing body formed in a predetermined shape in advance is put into a mold for forming the guard action portion and the connection tool, and the guard action portion and the connection tool are resin-molded to perform the guard action. It is possible to adopt a manufacturing method in which the guard working portion and the connecting tool are connected to the reinforcing member at the same time when the portion and the connecting tool are formed and the entire chain guard is completed. In other words, the reinforcing member can be formed without requiring coloring work so that a color or luster different from that of the guard acting portion can be seen. When the reinforcement is made of metal, the weight of the entire chain guard is lighter or the wall thickness is smaller than when the entire chain guard is made of resin only. A predetermined guard strength can be exerted by both the guard action portion and the guard action portion.

[0006]

[Effects of the Invention] Therefore, not only can the chain be prevented from falling off by the support action of the guard action portion of the chain guard, but also the action of the guard action portion made of resin allows the chain action.
The fall prevention was performed relatively quietly while preventing damage to the chain, so that the vehicle could run lightly and the service life was extended. When the annular reinforcement is made of metal,
With sufficient guard strength, the chain can be reliably prevented from falling off, and at the same time, it has become possible to make the chain relatively light or compact and to be used advantageously. Then, in this case, a color and gloss different from the guard action portion of the annular reinforcing body are seen, and it is made to be excellent in aesthetic appearance, and, in addition, the above-mentioned manufacturing method in which the reinforcing body is put into a mold is adopted. Then, it can be easily and inexpensively made. In addition, adopting a manufacturing method in which a reinforcing body is separately formed and put into a molding die, the labor is reduced and the color-coding accuracy is improved as compared with the adoption of coloring means, and a product with good finishing accuracy can be easily manufactured at low cost. I was able to do it. In addition, the annular reinforcement serves as a guard for the guard action part,
Since the guard action part is made of resin, it is made durable so as not to be easily damaged or broken.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, three front gears 1, 2, 3 are connected to a crank 4, and among the front gears 1 to 3, they are arranged at the outermost side of the vehicle body.
A bicycle front which has an annular chain guard 5 on the lateral outside of the large-diameter front gear 1 having the largest outer diameter, enables three-speed shifting, and prevents the chain from falling off the large-diameter front gear 1. A gear is configured.

The chain guard 5 has an annular guard action portion 5a as shown in FIG. 1 along the tooth tip of the large-diameter front gear 1, and reinforces the guard action portion 5a along the guard action portion 5a. And a reinforcing member 5b formed in an annular shape as described above, and as shown in FIG.
The guard action portion 5a and the reinforcing member 5b are connected to each other by a plurality of the first connection tool 6 and the second connection tool 7 which are distributed in the circumferential direction of the guard action portion 5a. The guard operating portion 5a is attached to the large-diameter front gear 1 by connecting the guard action portion 5a to the large-diameter front gear 1 by a book mounting arm 8. That is, the guard C is supported by the large-diameter front gear 1 via the mounting arm 8, and when the chain C comes off from the large-diameter front gear 1 laterally outward, the guard action portion 5 a comes into contact with the chain C to support and act. By providing the guard strength necessary for supporting the chain by both the guard action portion 5a and the reinforcing member 5b, the chain C is prevented from falling laterally outward from the large-diameter front gear 1. In order to connect the mounting arm 8 to the front gear 1, as shown in FIG. 3, the mounting arm 8 is provided with a connecting projection 8 a as a mounting portion that enters a long hole for mounting the front gear 1.
A mounting screw 9 is screwed to the mounting arm 8 through the mounting long hole of the front gear 1.

The reinforcing member 5b is made of an aluminum round bar which is bent and formed into an annular shape as shown in FIG. That is, in a state where the outer periphery side edge A of the reinforcing member 5b in the gear radial direction is located outside the guard acting portion 5a in the gear radial direction with respect to the guard acting portion 5a,
And an outer peripheral edge B of the reinforcing member 5b in the gear rotation axis center direction.
Are formed along with the guard action portion 5a in a state of being located outside the guard action portion 5a in the gear rotation axis center direction and having a gap between both ends through which the main body of the crank 4 passes. 3 and 4, the working end 5t of the guard working portion 5a is moved closer to the tip of the large-diameter front gear 1 than the reinforcing member 5b. In order to reduce the weight and size of the chain and to prevent noise and damage to the chain while preventing the chain from falling off, it is also more aesthetically pleasing. It is made to become. That is, since the reinforcing member 5b is made of a metal, a superior guard strength is exhibited as compared with the case where the reinforcing member 5b is made of a resin. Thus, the entire chain guard 5 can be reduced in weight or reduced in size while having a predetermined guard strength. When the chain C is prevented from falling off, the working end 5t of the guard working portion 5a comes into contact with the chain C prior to the reinforcing body 5b due to the positional relationship with the reinforcing body 5a, and the reinforcing body 5b It is difficult to make contact with the metal, and it is difficult for the metal to make contact noise. Even if the guard action portion 5a and the chain C come into contact with each other, the guard action portion 5a is made of resin, so that it is relatively difficult to generate contact noise and the chain is hardly damaged. Since the connecting members 6 and 7 are dispersed in the circumferential direction of the reinforcing member 5b, the reinforcing member 5b is exposed between the connecting members. This allows
The reinforcing member 5b has a different color and luster from the guard acting portion 5a provided for the metal member, so that the appearance is enhanced. The reinforcing member 5
b may be changed to various shapes other than circular, such as rectangular or hexagonal in cross section.

The thickness T1 of the reinforcing member 5b in the gear radial direction is formed to be larger than the thickness T2 of the guard acting portion 5a in the gear radial direction. That is, when the entire front gear is viewed from the lateral outside in the direction of the rotation axis, the reinforcing body 5b is
a, the color and luster of the reinforcing member 5b are conspicuous and beautiful. It is configured to be even higher. The reinforcing member 5b is connected to both ends of the reinforcing member 5b, and has a recess 10 as shown in FIG.
The connector 10 is provided with a resin-made connecting tool 10 having a. In other words, the main body of the crank 4 is brought as close as possible to the large-diameter front gear 1 so that the pedal can be arranged as close to the inside of the vehicle body as possible. If this consideration is not necessary, the reinforcing body may be formed in a complete ring-shaped annular shape in which both ends are directly connected without the gap between the both ends and the connecting tool.

[0011] The couplers 6, 7 and 10, and
The mounting arm 8 is made of resin and is molded integrally with the guard acting portion 5a. In forming the chain guard 5 and the mounting arm 8, etc., the following manufacturing method is adopted so that it can be easily manufactured. is there. That is, prior to forming the guard action portion 5a and the like, the annular reinforcing member 5b is formed in advance, and is formed in a mold for forming the guard action portion 5a, the couplings 6, 7, 10 and the mounting arm 8. The guard action portion 5a, the connecting members 6, 7, 10 and the mounting arm 8 are formed by resin molding with the reinforcing member 5b inserted thereinto, thereby forming the guard action portion 5a, the connecting members 6, 7, 10 and the mounting arm 8. Adopting a production method. Then, the guard action part 5a and the connecting tool 6,
At the same time as forming 7, 10 and mounting arm 8,
The guard action portion 5a and the connecting members 6, 7, 10 are connected to the reinforcing member 5b, and the mounting arm 8 is connected to the guard action portion 5a.
a, and the chain guard 5 is completed in a state where the mounting arm 8 has been mounted.

The first connector 6 of the connectors 6 and 7 is mounted on an extension of the mounting arm 8. Connector 6
And 7 are displaced in the circumferential direction of the mounting arm 8 and the reinforcing member 5b and connected to the guard action portion 5a.
Even if only the connecting tool 6 is directly connected to the mounting arm 8, the connection strength between the first connecting tool 6 and the mounting arm 8 is increased, and the support strength of the chain guard 5 by the mounting arm 8 is increased. .

[Another Embodiment] The chain guard may be modified and implemented as follows. First connecting on extension of mounting arm 8
The working portion 5a and the reinforcing member 5b may be connected by only one of the connecting member and the second connecting member not located on the extension of the mounting arm 8. The connection tool 10 may be omitted for implementation. In this case, the action portion 5a may have a shape having a cut through which the main body of the crank 4 passes. The number of the mounting arms 8 may be other than five. Further, the mounting arm may be connected to the gear by a mounting screw inserted from the outer side of the gear, or may have a shape in which a decorative hole exists in the middle. The length may be longer or shorter than that of FIG. In short, it may be formed in various different structures such as a connection structure with a gear, a specific shape and a length. The guard acting portion may be formed in a ring shape or may be formed so as to be scattered in the circumferential direction of the gear. Further, the present invention may be implemented by forming a gap between the reinforcing member and the reinforcing member.

The present invention can be applied to a case in which the reinforcing member 5b is made of various metals such as iron in addition to aluminum.

The present invention can be applied to a front gear capable of performing two-speed shifting in addition to a three-speed shifting. That is, the present invention can be applied to at least one large-diameter front gear and a front gear including at least one front gear having a smaller diameter than the large-diameter front gear. Therefore, the front gear 1 is referred to as a large-diameter front gear 1, and the medium-diameter front gear 2 is referred to as a small-diameter front gear 2.

In the claims of the utility model registration, reference numerals are written for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a side view of a bicycle front gear.

FIG. 2 is a sectional view of a bicycle front gear.

FIG. 3 is a cross-sectional view of a chain guard mounting portion.

FIG. 4 is a sectional view of a chain guard.

FIG. 5 is a bottom view of a connection portion of the reinforcing member.

[Explanation of symbols]

 Reference Signs List 1 large-diameter front gear 2 small-diameter front gear 5 chain guard 5a guard acting portion 5b annular reinforcing body 5t working end 6,7 connecting tool 8 mounting arm C chain T1 thickness of annular reinforcing body T2 thickness of guard acting portion A annular Outer peripheral edge in the gear radial direction of the reinforcing member B Outer peripheral edge in the gear rotation axis direction of the annular reinforcing member

Claims (5)

(57) [Scope of request for utility model registration] A bicycle front gear comprising at least one large-diameter front gear (1) and at least one small-diameter front gear (2) connected to a crank (4). And a guard action portion (5a) made of resin and the guard action portion (5a) along the guard action portion (5a).
a) a chain guard (5) that reinforces a) and has an annular reinforcing body (5b) formed separately from the guard action section (5a) and connected to the guard action section (5a). ,
It is arranged laterally outside the large-diameter front gear (1), and the working end (5t) of the guard working portion (5a) comes into contact with the chain (C) in preference to the annular reinforcing body (5b). A resin connecting member (6) disposed closer to the large-diameter front gear (1) than the annular reinforcing body (5b) and connecting the guard acting portion (5a) and the annular reinforcing body (5b). , (7) are integrally molded with the guard acting portion (5a) and are arranged in plural numbers in the circumferential direction of the annular reinforcing member (5b), and the chain guard (5) is attached to the large-diameter front gear.
(1) and is formed separately from the crank (4).
The large-diameter front gear via the mounting arm (8)
(1) and a mounting portion (8) for the large-diameter sprocket (1).
a) is provided on said mounting arm (8).
Front bicycle gear that. 2. The annular reinforcing member (5b) is made of metal and is positioned radially outward with respect to the guard acting portion (5a) in the gear radial direction, and the thickness of the annular reinforcing member (5b) in the gear radial direction. The bicycle front gear according to claim 1, wherein the thickness (T1) is greater than the thickness (T2) of the guard action portion (5a) in the gear radial direction. 3. The bicycle front gear according to claim 2, wherein said mounting arm (8) is made of resin and is integrally formed with said guard operating portion (5a). 4. The connector (6) is mounted on a longitudinal extension of the mounting arm (8).
Bicycle front gear as described. 5. A gear radial direction of said annular reinforcing member (5b).
The outer peripheral side edge (A) of the gear is larger in gear diameter than the guard action portion (5a).
Gear rotation of the annular reinforcing member (5b)
The outer peripheral edge (B) in the axial direction is the guard action portion (5a).
Claim 1 which is located outside the gear rotation axis center direction than
4. The bicycle front gear according to any one of 4.