JPS6333752Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a coaster brake mainly used for bicycles, and more specifically, a hub body having a braking surface on its inner circumferential surface has a circular outer surface in contact with the braking surface inside the hub body. The present invention relates to a coaster brake in which a brake shoe is displaceable in the radial direction of the hub body and is non-rotatable.

(Prior Art) Conventionally, in a coaster brake, a viscous lubricant is applied to the braking surface inside the hub body and the outer surface of the brake shoe to reduce the frictional heat generated at the contact portion between the brake shoe and the braking surface. In addition, a large number of grooves extending in the circumferential direction or the axial direction are provided on the outer surface of the shoe so that a portion of the lubricant is collected in the grooves.

However, in the case of this conventional coaster brake, the viscous lubricant in the groove melts due to the frictional heat generated at the contact area between the brake shoe and the braking surface and flows out from the groove, and this melted lubricant When the lubricant adheres to the brake surface, the dissolved lubricant adhered to the brake surface is scattered outward from both ends of the brake surface due to the pressure of the brake shoe on the brake surface, and is consumed. As a result, the lubricant in the groove was consumed quickly, resulting in poor durability of the brake shoe.

(Purpose of the invention) The present invention was devised in view of the above points, and includes a reservoir groove extending in the circumferential direction and a branch groove branching from the reservoir groove on the outer surface of the brake shoe. Among the lubricants that have flowed out from the reservoir groove and adhered to the braking surface, excess lubricant in excess of the required amount can be collected into the reservoir groove.

(Structure of the invention) Accordingly, the present invention has a brake shoe having an arcuate cross section in contact with the braking surface, which is displaceable in the radial direction of the hub body, and which is in contact with the braking surface within the hub body. In a coaster brake provided non-rotatably, a reservoir groove extending in the circumferential direction is provided on the outer surface of the brake shoe, and a reservoir groove is provided from both widthwise side surfaces of the reservoir groove outward in the axial direction in the forward rotational direction of the hub body. A branch groove is provided that slopes backward, and a viscous lubricant is stored in the reservoir groove. Out of the lubricant that flows out from the reservoir groove and adheres to the braking surface, excess lubricant in excess of the necessary amount is transferred to the branch groove. This makes it possible to collect it in the reservoir groove.

(Embodiment) An embodiment of the brake of the present invention will be described below based on the drawings.

The coaster brake shown in Fig. 1 has a brake cone 2 supported at one end of a fixed shaft 1 whose both ends are fixed to a bicycle frame, and a drive body 4 equipped with a sprocket 3 at the other end, which is freely rotatable via a bearing. A straight cylindrical hub body 5 having a braking surface 51 on the inner circumferential surface of one end is rotatably supported between the brake cone 2 and the driver 4 via a pair of bearings. A pair of brake shoes 6 having a circular outer surface that contacts the braking surface 51 is installed inside the hub body 5, and rotation of the shoes 6 is prevented between the shoes 6 and the brake cone 2. In addition, an engaging portion 7 is provided that can move the shoe 6 toward and away from the braking surface 51, and an engaging portion 7 is provided between the driver 4 and the brake shoe 6 in the hub body 5. A transmission mechanism 8 is interposed to change the speed of the power and transmit it to the hub body 5, and a brake cylinder 9 having a brake cam surface 9a on the outer peripheral surface is inserted into the transmission mechanism 8 so as to protrude into the inside of the brake shoe 6. The shoe 6 is supported on the cam surface 9a of the brake cylinder 9 via a plurality of rollers 10, and the reverse rotation of the drive body 4 due to reverse depression of the pedal is controlled by the transmission mechanism 8 and the brake cylinder 9. and is transmitted to the shoe 6 via the roller 10, and the brake shoe 6 is displaced in the radial direction and pressed against the braking surface 51 to perform braking. A spring groove 61 extending in the circumferential direction is provided on the outer surface of the brake shoe 6, and a C-shaped ring is provided in the spring groove 61 to constantly bias the shoe 6 in a direction away from the braking surface 51. A spring 11 is fitted.

In the coaster brake constructed as described above, this invention provides a reservoir groove 62 extending in the circumferential direction on the outer surface of the brake shoe 6, and extends outward in the axial direction from both widthwise side surfaces 62a, 62b of the reservoir groove 62. , branch grooves 63 and 64 that are inclined rearward in the direction of arrow X in FIGS. 2 and 3 in the normal rotation direction of the hub body 5;
was established.

In the illustrated example, the reservoir grooves 62 are provided on both sides of the spring groove 61, and a viscous lubricant such as grease is stored in these reservoir grooves 62, and the branch grooves are provided on both sides of each reservoir groove 62. 63,64
The braking surface 51 of the brake shoe 6 is
When the braking surface 51 comes into contact with
3 and 64, guided to the reservoir groove 62 along these branch grooves 63 and 64, and collected into the reservoir groove 62.

Note that the number of the reservoir grooves 62 may be one. in this case,
The spring groove 61 may be moved toward one end of the brake shoe, and the reservoir groove 62 may be formed in the center.
Further, the spring groove 61 may be formed to be larger than the accommodation area of the ring spring 11, and a part of the spring groove 61 may be used as the reservoir groove 62. Moreover, the branch groove 6
In addition to providing a plurality of number 3 and 64 on both sides of the reservoir groove 62, one each may be provided.

A viscous lubricant such as grease is applied to the braking surface 51 portion of the coaster brake constructed as described above and the outer surface of the brake shoe 6, and a portion of the lubricant is applied to the reservoir groove 6 on the outer surface of the brake shoe 6. The lubricant is stored in the branch grooves 63 and 64, and when braking is performed by pressing the brake shoe 6 against the braking surface 51, the lubricant increases the lubricant at the contact portion of the shoe 6 with the braking surface 51.

During this braking, the lubricant applied to the braking surface 51 portion and the contact portion of the outer surface of the shoe 6 with the braking surface 51 is applied to the braking surface 51 as the shoe 6 is displaced radially outward. Since it is pushed away to both ends, it is consumed in a relatively short period of time, but the storage groove 62
Also, the lubricant in the branch grooves 63 and 64 is difficult to be consumed.

However, due to repeated braking operations, frictional heat of a predetermined temperature or higher is generated at the contact portion of the shoe 6 with the braking surface 51, causing the reservoir groove 62 and the branch groove 6 to
When the viscous lubricant in 3 and 64 melts, the lubricant falls from the lower part of the brake shoe 6 and accumulates at the bottom of the hub body 5, and the lubricant accumulated at the bottom of the hub body 5 also dissolves. The agent adheres to the entire surface of the braking surface 51 as the hub cylinder 5 rotates.

When the shoe 6 is pressed against the braking surface 51 in this state, the excess lubricant not involved in lubrication and exceeding the required amount among the lubricants adhering to the braking surface 51 is removed from the branch groove 6 on the outer surface of the shoe 6. , 64, and the lubricant in the branch grooves 63, 64 is attracted in the rotational direction of the hub body 5 as the hub body 5 rotates, and flows into the reservoir along the branch grooves 63, 64. It flows into the groove 62 and is collected in the reservoir groove 62. Therefore, wasteful consumption of lubricant can be reduced, this lubricant can be used effectively, and the durability of the brake shoe 6 can be improved.

The illustrated coaster brake is configured such that a transmission mechanism 8 is installed inside the hub body 5 and the power of the driving body 4 is transmitted to the brake shoe 6 via the transmission mechanism 8. It may be a coaster brake that does not have a structure.

(Effects of the invention) As described above, according to the invention, the viscous lubricant can be stored in the circumferential groove provided on the outer surface of the brake shoe having a circular outer surface, and furthermore,
Since branch grooves are provided axially outward from both widthwise side surfaces of the reservoir groove, the branch grooves are inclined rearward in the forward rotation direction of the hub body, so that dissolved lubricant that flows out from the reservoir groove and adheres to the braking surface. Among the lubricants, excess lubricant in excess of the required amount can be guided from the branch groove to the reservoir groove and collected in the reservoir groove. Therefore, wasteful consumption of lubricant can be reduced, and this lubrication This makes it possible to use the agent effectively and improve the durability of the brake shoe.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the brake of the present invention, FIG. 2 is a longitudinal sectional side view of the main parts, and FIG. 3 is a perspective view of only the brake shoe. 5... Hub body, 51... Braking surface, 6... Brake shoe, 62... Reservoir groove, 63, 64... Branch groove.

Claims (1)

[Scope of utility model registration request] In the coaster brake, a brake shoe having a circular outer surface in contact with the braking surface is disposed in a hub barrel having a braking surface on an inner circumferential surface so as to be displaceable in the radial direction of the hub barrel and non-rotatable. A reservoir groove extending in the circumferential direction is provided on the outer surface of the brake shoe, and branch grooves are provided axially outwardly from both widthwise side surfaces of the reservoir groove that slope rearward in the forward rotation direction of the hub body. A coaster brake that is characterized by: