JPH0347033Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention is a driven sprocket cover that serves as a chain guide plate for a driven sprocket of a motorcycle and a cover for a fastening member that connects the driven sprocket to a rear wheel boss. Regarding.

(Prior art and its problems) In chain drive type motorcycles, a chain is routed between a drive sprocket on the engine side and a driven sprocket provided on the rear wheel hub side, and the driving force of the drive sprocket is transferred to the chain drive sprocket. The signal is transmitted to the driven sprocket via the chain to drive the rear wheel. In such a drive system, a chain guide member is provided on the driven sprocket side to prevent the chain from getting caught when it comes off. Such a chain guide member is disclosed in Japanese Utility Model Publication No. 57-42152.
As shown in FIG. 5, a driven sprocket 4 is connected to one side end of the rear wheel bub 1 by a fastening member consisting of a bolt 2 and a nut 3, and a large diameter hole 5a is installed in the end surface of the driven sprocket 4. A chain guide 5 in the shape of a circular dish with a hole drilled therein is fixed via a rivet 6, and when the chain 7 is detached from the driven sprocket 4, it is supported as shown by the two-dot chain line 7', and the chain guide 5 is held in place by the chain guide 5. It is designed to prevent such problems.

However, since the chain guide 5 has a structure in which a large-diameter hole 5a is simply bored in the center of the end face, it needs to be formed thickly in order to increase strength, which not only causes an increase in weight but also causes problems with bolts. 2. The fastening members such as the nuts 3 are conspicuous, lack aesthetics, and are not very desirable in terms of appearance. Further, there is a problem in that dust and the like easily enter through the holes 5a, making the inside dirty.

(Purpose of the invention) The present invention has been made in view of the above points, and aims to increase the strength of the driven sprocket cover, improve aesthetics, and reduce the intrusion of dust into the interior.

(Summary of the invention) In order to achieve the above purpose, in this invention,
It is fixed to the outer surface of a driven sprocket that is removably connected to one side end of a rear wheel hub of a motorcycle by a plurality of fastening members, and surrounds the protruding portion of each of the fastening members from the outer surface of the driven sprocket. In a circular plate-shaped driven sprocket cover, holes are formed in the driven sprocket cover at locations facing the respective fastening members, through which the respective fastening members can be attached and detached, and the opening ends of these holes are respectively The present invention provides a driven sprocket cover for a motorcycle that is erected facing each of the opposing fastening members to form a flange.

(Embodiment of the invention) An embodiment of the invention will be described below in detail based on the accompanying drawings.

In Figures 1 and 2, the rear fork 10
A rear wheel hub 13 is rotatably supported on a rear axle 11 via a bearing 12, and a driven sprocket 14 is connected to a bolt 15, a buffer member 16, and a nut at one end of the rear wheel hub 13. A drive chain 19 is connected between the driven sprocket 14 and a drive sprocket on the engine side (not shown). has been done.

The driven sprocket cover 20 has a circular plate shape as shown in FIGS. 3 and 4, and its inner diameter surrounds each nut 17 of each fastening member 18, and its depth is equal to that of the driven sprocket of each bolt 15. 1
It is set to a predetermined dimension larger than the protrusion dimension from the outer surface of No. 4. Open end 20a of the cover 20
A flange 20b is formed on the flange 20b.
A plurality of bosses 20d, for example four bosses 20d having holes 20c formed therein, are provided at equal intervals in the circumferential direction. A hole 2 for inserting the rear axle is provided in the center of the end surface 20e.
0f is bored, and each tightening nut 1 of the four fastening members 18 is provided at the peripheral edge of the end face 20e.
A hole 20g is bored at a position facing 7.
The diameter of each of these holes 20g is set to a size that allows a tool such as a box wrench for tightening or loosening the nut 17 to pass through freely, and the open end thereof is inward and perpendicular to the end surface 20e as shown in FIG. It is erected and forms a flange 20h.

The flange 20h has the function of reinforcing the cover 20 and as a guide when attaching and detaching the nut 17, and its width (height from the end surface 20e) is such that the inner peripheral surface of the tip is the same when the nut 17 is tightened on the bolt 15. It is set to such an extent that it surrounds the upper part of the nut 17. This cover 20 is integrally formed of, for example, an iron plate.

As shown in FIG. 2, this cover 20 is attached to the outer surface of the driven sprocket 14.
Each hole 20c drilled in the flange 20b is arranged to face each hole 14a drilled in the driven sprocket 14 opposite to each hole 20c,
It is firmly fixed by rivets 21 fitted into these holes 20c and 14a. In this state,
Each nut 17 has 20 g of each opposing hole in the cover 20.
and is surrounded by the cover 20 so as to be inconspicuous. Also, chain 19
When the cover 20 comes off, the two-dot chain line 1
It is supported as shown at 9'.

When attaching or detaching each nut 17, the aforementioned box wrench is inserted through each opposing hole 20g of the cover 20, and each nut 17 is tightened or loosened. Each of these nuts 17 is guided by the flange 20h during attachment and detachment, and does not fall into the cover 20, making assembly easy.

(Effects of the invention) As explained above, according to the invention, a driven sprocket is fixed to the outer surface of a driven sprocket that is removably connected to one side end of a rear wheel hub of a motorcycle using a plurality of fastening members. In a circular plate-shaped driven sprocket cover that surrounds a portion of the fastening member protruding from the outer surface of the driven sprocket,
A hole through which each of these fastening members can be attached and detached is formed at a portion of the driven sprocket cover facing each of the fastening members, and the opening end of each of these holes is erected facing each of the opposing fastening members. Since the cover is provided with a flange to form a flange, the strength of the cover can be increased, and as a result, the cover can be made thinner and lighter, and the fastening member becomes less noticeable, improving aesthetics. do. Furthermore,
The flange can be used as a guide when attaching and detaching the fastening member, making it possible to improve the ease of assembly, and also being advantageous in that it is possible to reduce the intrusion of dust into the interior.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the main parts of a motorcycle to which the driven sprocket cover according to the present invention is applied;
The figure is a cross-sectional view along the arrow line in Figure 1, Figure 3 is a plan view of the driven sprocket cover, Figure 4 is a cross-sectional view along the arrow line in Figure 3, and Figure 5 is a conventional chain guide on the driven sprocket. It is a sectional view of the state where is attached. 13... Rear wheel hub, 14... Driven sprocket, 18... Fastening member, 20... Driven sprocket cover.

Claims (1)

[Scope of utility model registration request] It is fixed to the outer surface of a driven sprocket that is removably connected to one side end of a rear wheel hub of a motorcycle by a plurality of fastening members, and surrounds the protruding portion of each of the fastening members from the outer surface of the driven sprocket. In a circular plate-shaped driven sprocket cover, holes are formed in the driven sprocket cover at locations facing the respective fastening members, through which the respective fastening members can be attached and detached, and the opening ends of these holes are respectively A driven sprocket cover for a motorcycle, characterized in that the driven sprocket cover for a motorcycle is erected facing each of the opposing fastening members to form a flange.