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Patent Searching and Data

Document Type and Number:
Japanese Patent JP2003312466
Kind Code:

To enhance responsiveness when a master cylinder is operated abruptly.

In this master cylinder wherein a pressure chamber Rp2 formed by a cylinder housing 10, a seal cup 21 and a piston 32 is communicated with an atmospheric-pressure chamber Ra2 through a communication passage 32a formed in the piston 32, under the condition where the piston 32 is located in an original position, and wherein the communication between the communication passage 32a and the atmospheric-pressure chamber Ra2 is blocked with the seal cup 21 under the condition where the piston 32 is moved from the original position to a moving direction by a prescribed distance, a stepped hole of which the end part opened in an outer circumferential face of a hollow end part 32b of the piston 32 is made large in its diameter (32a2), and of which the end part communication-opened in an inner circumferential face (pressure chamber Rp2) of the hollow end part 32b of the piston 32 is made small in its diameter (32a1) is adopted as the communication passage 32a, and a passage cross-sectional area of the small-diametric part 32a1 is set to exhibit a contraction effect in the small-diametric part 32a1 in the stepped hole.

Kusano, Akihito
Ishida, Satoshi
Application Number:
Publication Date:
November 06, 2003
Filing Date:
April 25, 2002
Export Citation:
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International Classes:
B60T11/16; B60T11/20; (IPC1-7): B60T11/16
Attorney, Agent or Firm:
大庭 咲夫 (外1名)