Pump equipment and method for assembling same

A pump equipment for a hydraulic circuit comprising:

• a casing having a shaft hole;
• a drive shaft rotatably fitted into the shaft hole;
• a pump room provided in the casing;
• a rotor member contained in the pump room to be rotated by the drive shaft;
• an intake port and a discharge port respectively arranged on side walls of the pump room for sucking fluid from the hydraulic circuit and discharging compressed fluid to the hydraulic circuit according to the rotation of the rotor member;
• an intake conduit provided in the casing and connectable the intake port to the hydraulic circuit;
• a branched intake conduit branched out from the intake conduit and connected to the shaft hole;
• a first oil seal arranged inside the shaft hole and around the drive shaft for sealing fluid flowing through a clearance between the shaft hole and the drive shaft;
• and
• a second oil seal arranged inside the shaft hole and around the drive shaft at a position adjacent to the first oil seal in a direction opposite to the rotor member for sealing fluid leaked through the first oil seal.

A pump equipment for a hydraulic circuit, comprising:

• a drive shaft;
• first rotary pumps to be driven by the drive shaft, the first rotary pump comprising a first rotors to be rotated by the drive shaft, a first cylindrical center plate, first and second cylinders, a pump room constructed by putting the first cylindrical center plate between the first and second cylinders for containing the first rotors therein and a first intake port and a first discharge port provided in the first cylinder for sucking fluid from the hydraulic circuit and discharging compressed fluid to the hydraulic circuit;
• second rotary pump to be driven by the drive shaft, the second rotary pump comprising second rotors to be rotated by the drive shaft, a second cylindrical center plate, the second cylinder, a third cylinder, a pump room constructed by putting the second cylindrical center plate between the second and third cylinders for containing the second rotors therein and a second intake port and a second discharge port provided in the third cylinder for sucking fluid from the hydraulic circuit and discharging compressed fluid to the hydraulic circuit;
• center bores provided respectively in the first, second and third cylinders, into which the drive shaft is rotatably fitted;
• first and second intake conduits provided respectively in the first and third cylinders and connectable the first and second intake ports to the hydraulic circuit, respectively;
• first and second branched intake conduits branched out respectively from the first and second intake conduits and connected to the center bores of the first and second cylinders, respectively;
• a first oil seal arranged inside the center bore of the third cylinder and around the drive shaft for sealing fluid flowing through a clearance between the center bores and the drive shaft;
• and
• a second oil seal arranged inside the center bore of the third cylinder and around the drive shaft at a position adjacent to the first oil seal in a direction opposite to the second rotors for sealing fluid leaked through the first oil seal.

A pump equipment for hydraulic circuit comprising:

• a drive shaft;
• plural rotary pumps to be driven by the drive shaft;
• an intake port provided in each of the plural rotary pumps for sucking fluid;
• and
• a discharge port provided in each of the plural rotary pumps for discharging the fluid in high pressure;
• wherein the respective discharge ports are located at the places where the respective reaction forces against the drive shaft to be produced by the high pressure fluid are cancelled out and counterbalanced each other.

A brake apparatus comprising:

• a brake fluid pressure generating device for generating fluid pressure in accordance with depression force;
• first and second braking force producing devices for producing braking force on wheels;
• a first conduit line provided with a first main conduit and a first auxiliary conduit, the first main conduit connected to the brake fluid pressure generating device for transmitting brake fluid to the first braking force producing device and the first auxiliary conduit also connected to the brake fluid pressure generating device for supplying additional brake fluid to the first main conduit in order to increase the braking force to be produced by the first braking force producing device;
• and
• a second conduit line provided with a second main conduit and a second auxiliary conduit, the second main conduit connected to the brake fluid pressure generating device for transmitting brake fluid to the second braking force producing device and the second auxiliary conduit also connected to the brake fluid pressure generating device for supplying additional brake fluid to the second main conduit in order to increase the braking force to be produced by the second braking force producing device;
• a first rotary pump disposed in the first auxiliary conduit, the first rotary pump having a first intake port facing to the brake fluid pressure generating device and a first discharge port facing to the braking force producing device;
• a second rotary pump disposed in the second auxiliary conduit, the second rotary pump having a second intake port facing to the brake fluid pressure generating device and a second discharge port facing to the braking force producing device;
• wherein a drive shaft drives the first and second rotary pumps and the first and second discharge ports are located at the points nearly symmetrical with respect to the center axis of the drive shaft.

A method for assembling a pump equipment having a drive shaft and first and second rotary pumps, wherein the first rotary pump is comprised of first rotors to be rotated by the drive shaft, a first cylindrical center plate, first and second cylinders and a pump room constructed by putting the first cylindrical center plate between the first and second cylinders for containing the first rotors therein, and the second rotary pump is comprised of second rotors to be rotated by the drive shaft, a second cylindrical center plate, the second cylinder, a third cylinder and a pump room constructed by putting the second cylindrical center plate between the second and third cylinders for containing the second rotors therein, and, further, wherein the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder are stacked one on top of another and fixed together, comprising the steps of:

• piling up the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder;
• applying laser beam, as a spot welding, to a part of the respective peripheral borders of the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder;
• and
• welding finally all around the respective peripheral borders of the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder.

A method for assembling a pump equipment having a drive shaft and first and second rotary pumps, wherein the first rotary pump is comprised of first rotors to be rotated by the drive shaft, a first cylindrical center plate, first and second cylinders and a pump room constructed by putting the first cylindrical center plate between the first and second cylinders for containing the first rotors therein, and the second rotary pump is comprised of second rotors to be rotated by the drive shaft, a second cylindrical center plate, the second cylinder, a third cylinder and a pump room constructed by putting the second cylindrical center plate between the second and third cylinders for containing the second rotors therein, and, further, wherein the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder are stacked one on top of another and fixed together, comprising the steps of:

• piling up the third cylinder and the second cylindrical center plate;
• making a first subassembly by temporally fastening with a first screw the third cylinder and the second cylindrical center plate;
• piling up the second cylinder, first cylindrical center plate and the first cylinder;
• making a second subassembly by temporally fastening with a second screw the second cylinder, first cylindrical center plate and the first cylinder;
• piling the first and second subassemblies;
• and
• welding all around the respective peripheral borders of the first cylinder, the first cylindrical center plate, the second cylinder, the second cylindrical center plate and the third cylinder.