A vehicle height adjustment apparatus according to one embodiment include a spring, a spring-length changing unit, a first valve, a control valve and a second valve. The spring-length changing unit changes a length of the spring in accordance with an amount of oil in a jack chamber that accommodates the oil. The first valve opens and closes a first communication path in which the oil supplied from a pump is oriented toward a reservoir chamber that stores the oil. The control valve opens and closes a discharge flow path oriented toward the reservoir chamber from a chamber that accommodates the oil to close the first valve. The second valve opens and closes a second communication path in which the oil supplied from the pump is oriented toward the jack chamber when the first valve is closed.

A suspension device includes a spring, a jack, a reservoir chamber which reserves the oil, a first pump, a second pump an opening and closing unit. The second pump is configured to cause the oil to flow into the housing chamber and to cause the oil to flow out from the housing chamber.

A vehicle height adjustment system includes: a cylinder housing part having an inner space configured to receive working fluid; a piston part positioned in the cylinder housing part, the piston part configured to move linearly in response to the working fluid transferred to the cylinder housing; a damper rod part positioned in the piston part; a protrusion part protruding outward from the damper rod part; and a guide part formed in the piston part facing the protrusion part, wherein the protrusion part is inserted into the guide part.

A vehicle height adjustment system includes: a cylinder housing part having an inner space configured to receive working fluid; a piston part positioned in the cylinder housing part, the piston part configured to move linearly, in response to a working fluid, in a moving direction along the cylinder housing part; and a rotation suppressing bracket coupled to the cylinder housing part and connected to a side surface of the piston part, the rotation suppressing bracket configured to suppress rotational movement with respect to the moving direction of the piston part.

A vehicle height adjustment system includes: a cylinder housing part having an inner space configured to receive working fluid; a piston part positioned in the cylinder housing part, the piston part configured to move linearly in response to the working fluid transferred to the cylinder housing; a damper rod part positioned in the piston part; a protrusion part protruding outward from the damper rod part; and a guide part formed in the piston part facing the protrusion part, wherein the protrusion part is inserted into the guide part.

A suspension bearing unit for a motor vehicle, comprising an upper cup, a lower cup and a bearing interposed between the upper cup and the lower cup in rotation in relation to each other about a principal axis. The suspension bearing unit also comprises at least one seal in a hollow housing provided on one face of a first element from among the lower cup and the upper cup. The hollow housing comprises a plurality of protruding ribs spaced apart circumferentially, the ribs protruding into the base of the seal.

A suspension bearing unit for a motor vehicle, comprising an upper cup, a lower cup and a bearing interposed between the upper cup and the lower cup in rotation in relation to each other about a principal axis. The suspension bearing unit also comprises at least one seal in a hollow housing provided on one face of a first element from among the lower cup and the upper cup. The hollow housing comprises a plurality of protruding ribs spaced apart circumferentially, the ribs protruding into the base of the seal.

In a method for determining an axle load on a mechanically and/or pneumatically/hydraulically suspended vehicle, the axle load is determined with the aid of control and sensor means that are installed in the vehicle and/or functionally enhanced. Functions for axle load determination at mechanically suspended vehicle axles (4) and for axle load determination at pneumatically/hydraulically suspended vehicle axles (2) are available. In a mechanically suspended vehicle axle (4) a distance measuring unit (9), and in a pneumatically/hydraulically suspended vehicle axle (2) a pressure measuring unit (7) are used to determine the axle load. An initial plausibility check is implemented in an electronic control unit (10) of the level control system (1), on the basis of which the level control system (1) identifies the particular suspension type, mechanical or pneumatic/hydraulic, of a vehicle axle (2, 4) and, thereafter, the appropriate function for axle load determination is activated.

A drive device for an electric truck provided with double-tires, the drive device including drive units provided to each of the double-tires on left and right sides of the electric truck, each of the drive units including a drive unit housing integrally accommodating a motor that generates drive power, a reducer that reduces a rotation speed of the motor, and a final gear that is connected to the reducer and transfers the drive power of the motor to a drive shaft of the double-tire. The drive device further including suspension parts one integrally integrated with above the final gear in the drive unit housing of each of the drive units and steering gear parts one integrally integrated with above each of the suspension parts and being configured to be steerable the double-tire.

A drive device for an electric truck provided with double-tires, the drive device including drive units provided to each of the double-tires on left and right sides of the electric truck, each of the drive units including a drive unit housing integrally accommodating a motor that generates drive power, a reducer that reduces a rotation speed of the motor, and a final gear that is connected to the reducer and transfers the drive power of the motor to a drive shaft of the double-tire. The drive device further including suspension parts one integrally integrated with above the final gear in the drive unit housing of each of the drive units and steering gear parts one integrally integrated with above each of the suspension parts and being configured to be steerable the double-tire.