Caliper brake apparatus

1. A caliper brake apparatus configured to apply a brake to a vehicle wheel by applying frictional force to a disc that rotates together with the vehicle wheel, comprising:

a caliper main body;

a piston provided to be free to advance into the caliper main body and retreat out of the caliper main body, the piston being configured to advance and retreat in accordance with a pressure in a pressure chamber of the caliper main body;

a brake shoe configured to be capable of applying frictional force to the disc by sliding against the disc;

a guide plate attached to the piston so as to support the brake shoe; and

a fastening member configured to fasten the piston to the guide plate,

wherein the fastening member has a tapered seating surface,

at least one of the piston and the guide plate includes a tapered contact portion on which the seating surface of the fastening member is seated, and

the piston includes a housing recessed portion that forms an air chamber capable of housing a part of the fastening member, and a cap member configured to close an open end of the housing recessed portion.

2. The caliper brake apparatus as defined in claim 1 , wherein the fastening member comprises:

a bolt having a screw shaft;

a tapered bolt side seating surface positioned between the bolt and the guide plate; and

a nut screwed to the screw shaft.

3. The caliper brake apparatus as defined in claim 2 , wherein the bolt includes a head portion on which the bolt side seating surface is formed, and the screw shaft provided to extend from the head portion,

the guide plate includes a first housing portion having a tapered bolt contact portion on which the bolt side seating surface is seated, and a first insertion hole into which the screw shaft is inserted, and

the guide plate is fastened to the piston by screwing the nut to the screw shaft projecting to the piston side through the first insertion hole.

4. The caliper brake apparatus as defined in claim 3 , wherein the bolt contact portion is formed as an indentation in the guide plate, and

a depth of the bolt contact portion is set to be greater than a thickness of the head portion of the bolt.

5. The caliper brake apparatus as defined in claim 1 , wherein the fastening member comprises:

a bolt having a screw shaft;

a nut screwed to the screw shaft; and

a tapered nut side seating surface positioned between the nut and the piston.

6. The caliper brake apparatus as defined in claim 5 , wherein the fastening member further comprises a washer that is configured to be penetrated by the screw shaft and includes the nut side seating surface,

the piston includes a second housing portion that serves as the housing recessed portion, and includes a tapered washer contact portion on which the nut side seating surface of the washer is seated, and a second insertion hole into which the screw shaft is inserted, and

the guide plate is fastened to the piston by screwing the nut to the screw shaft projecting to the second housing portion side through the second insertion hole via the washer.