Oil circuit system, lifting device, electric jack, press, crane, and tire mounting/dismounting and transport apparatus

A lifting device, characterized by comprising a hydraulic pump and a driving mechanism, wherein the hydraulic pump comprises a drive spindle and a pump body;

• the lifting device further comprises an oil circuit system, and the oil circuit system comprises:
• a lifting oil cylinder, a tank, a first oil feed line, a second oil feed line, an oil inlet/outlet line, a pressure relief line, an oil return line, a first valve, and a second valve;
• wherein the first valve is connected with the first oil feed line, the pressure relief line, and the oil return line;
• the second valve is connected with the first oil feed line and the oil return line;
• the oil inlet/outlet line has one end connected with the first oil feed line and the second oil feed line, and another end connected with the lifting oil cylinder;
• in a first operating condition of the lifting oil cylinder, both the first oil feed line and the second oil feed line supply hydraulic oil to the lifting oil cylinder;
• in a second operating condition of the lifting oil cylinder, the second oil feed line supplies the hydraulic oil to the lifting oil cylinder, the hydraulic oil within the first oil feed line flows to the oil return line via the second valve and returns to the tank;
• an oil pressure within the lifting oil cylinder in the second operating condition is greater than an oil pressure within the lifting oil cylinder in the first operating condition;
• and
• the first oil feed line comprises a gear pump assembly, the second oil feed line comprises a plunger pump assembly, and the drive spindle is configured to drive the gear pump assembly and the plunger pump assembly.

An electric jack, characterized by comprising:

• a lifting device and a jacking mechanism;
• the lifting device comprises a hydraulic pump and a driving mechanism, wherein the hydraulic pump comprises a drive spindle and a pump body;
• the lifting device further comprises an oil circuit system, and the oil circuit system comprises:
• a lifting oil cylinder, a tank, a first oil feed line, a second oil feed line, an oil inlet/outlet line, a pressure relief line, an oil return line, a first valve, and a second valve;
• wherein the first valve is connected with the first oil feed line, the pressure relief line, and the oil return line;
• the second valve is connected with the first oil feed line and the oil return line;
• the oil inlet/outlet line has one end connected with the first oil feed line and the second oil feed line, and another end connected with the lifting oil cylinder;
• in a first operating condition of the lifting oil cylinder, both the first oil feed line and the second oil feed line supply hydraulic oil to the lifting oil cylinder;
• in a second operating condition of the lifting oil cylinder, the second oil feed line supplies the hydraulic oil to the lifting oil cylinder, the hydraulic oil within the first oil feed line flows to the oil return line via the second valve and returns to the tank;
• an oil pressure within the lifting oil cylinder in the second operating condition is greater than an oil pressure within the lifting oil cylinder in the first operating condition;
• the first oil feed line comprises a gear pump assembly, the second oil feed line comprises a plunger pump assembly, and the drive spindle is configured to drive the gear pump assembly and the plunger pump assembly;
• and
• the jacking mechanism is connected with the lifting device, and the lifting device is configured to drive the jacking mechanism to perform lifting and lowering.

A press, characterized by comprising:

• a lifting device and a pressure block;
• the lifting device comprises a hydraulic pump and a driving mechanism, wherein the hydraulic pump comprises a drive spindle and a pump body;
• the lifting device further comprises an oil circuit system, and the oil circuit system comprises:
• a lifting oil cylinder, a tank, a first oil feed line, a second oil feed line, an oil inlet/outlet line, a pressure relief line, an oil return line, a first valve, and a second valve;
• wherein the first valve is connected with the first oil feed line, the pressure relief line, and the oil return line;
• the second valve is connected with the first oil feed line and the oil return line;
• the oil inlet/outlet line has one end connected with the first oil feed line and the second oil feed line, and another end connected with the lifting oil cylinder;
• in a first operating condition of the lifting oil cylinder, both the first oil feed line and the second oil feed line supply hydraulic oil to the lifting oil cylinder;
• in a second operating condition of the lifting oil cylinder, the second oil feed line supplies the hydraulic oil to the lifting oil cylinder, the hydraulic oil within the first oil feed line flows to the oil return line via the second valve and returns to the tank;
• an oil pressure within the lifting oil cylinder in the second operating condition is greater than an oil pressure within the lifting oil cylinder in the first operating condition;
• the first oil feed line comprises a gear pump assembly, the second oil feed line comprises a plunger pump assembly, and the drive spindle is configured to drive the gear pump assembly and the plunger pump assembly;
• and
• the lifting oil cylinder is provided with a piston rod which is liftable, and the piston rod is connected with the pressure block.

A crane, characterized by comprising:

• a lifting device and a boom;
• the lifting device comprises a hydraulic pump and a driving mechanism, wherein the hydraulic pump comprises a drive spindle and a pump body;
• the lifting device further comprises an oil circuit system, and the oil circuit system comprises:
• a lifting oil cylinder, a tank, a first oil feed line, a second oil feed line, an oil inlet/outlet line, a pressure relief line, an oil return line, a first valve, and a second valve;
• wherein the first valve is connected with the first oil feed line, the pressure relief line, and the oil return line;
• the second valve is connected with the first oil feed line and the oil return line;
• the oil inlet/outlet line has one end connected with the first oil feed line and the second oil feed line, and another end connected with the lifting oil cylinder;
• in a first operating condition of the lifting oil cylinder, both the first oil feed line and the second oil feed line supply hydraulic oil to the lifting oil cylinder;
• in a second operating condition of the lifting oil cylinder, the second oil feed line supplies the hydraulic oil to the lifting oil cylinder, the hydraulic oil within the first oil feed line flows to the oil return line via the second valve and returns to the tank;
• an oil pressure within the lifting oil cylinder in the second operating condition is greater than an oil pressure within the lifting oil cylinder in the first operating condition;
• the first oil feed line comprises a gear pump assembly, the second oil feed line comprises a plunger pump assembly, and the drive spindle is configured to drive the gear pump assembly and the plunger pump assembly;
• and
• the lifting oil cylinder is provided with a piston rod which is liftable, the boom is provided with a hook, and the boom is connected with the piston rod.

A tire mounting/dismounting and transport apparatus, characterized by comprising:

• a lifting device and a tire V-block;
• the lifting device comprises a hydraulic pump and a driving mechanism, wherein the hydraulic pump comprises a drive spindle and a pump body;
• the lifting device further comprises an oil circuit system, and the oil circuit system comprises:
• a lifting oil cylinder, a tank, a first oil feed line, a second oil feed line, an oil inlet/outlet line, a pressure relief line, an oil return line, a first valve, and a second valve;
• wherein the first valve is connected with the first oil feed line, the pressure relief line, and the oil return line;
• the second valve is connected with the first oil feed line and the oil return line;
• the oil inlet/outlet line has one end connected with the first oil feed line and the second oil feed line, and another end connected with the lifting oil cylinder;
• in a first operating condition of the lifting oil cylinder, both the first oil feed line and the second oil feed line supply hydraulic oil to the lifting oil cylinder;
• in a second operating condition of the lifting oil cylinder, the second oil feed line supplies the hydraulic oil to the lifting oil cylinder, the hydraulic oil within the first oil feed line flows to the oil return line via the second valve and returns to the tank;
• an oil pressure within the lifting oil cylinder in the second operating condition is greater than an oil pressure within the lifting oil cylinder in the first operating condition;
• the first oil feed line comprises a gear pump assembly, the second oil feed line comprises a plunger pump assembly, and the drive spindle is configured to drive the gear pump assembly and the plunger pump assembly;
• and
• the lifting oil cylinder is provided with a piston rod, and the tire V-block and the piston rod are connected.