Hydraulic composite bushing, flow channel for same, and method for forming flow channel

A hydraulic composite bushing, comprising:

• a core shaft;
• a rubber member, arranged on an outer peripheral surface of the core shaft and provided with two recesses diametrically opposite to each other;
• two support rings arranged around the rubber member and spaced apart from each other;
• and
• an outer casing press-fitted on the support rings from a radially outer side thereof through interference fit,
• wherein the outer casing covers the recesses to form two hydraulic chambers for accommodating hydraulic fluid between the rubber member and the outer casing, and at least one of the support rings is provided with a flow channel for the hydraulic fluid, so that said two hydraulic chambers are in communication with each other via the flow channel;
• a sealing device is provided at a connection between the outer casing and each of the recesses to seal each hydraulic chamber;
• wherein the flow channel comprises a first sub flow channel and two second sub flow channels connected to both ends of the first sub flow channel respectively, wherein the first sub flow channel is formed in an outer peripheral surface of said at least one of the support rings and extends in the circumferential direction, and the two second sub flow channels are formed inside said one of the support rings and in communication with respective hydraulic chambers in the rubber member;
• and
• a sealing gasket is provided on an outer side of the first sub flow channel, and a second rubber layer is vulcanized on an inner side of the sealing gasket, so that a seal is formed between the first sub flow channel and the outer casing by the sealing gasket.