A drive device for an electric truck includes drive unit housings provided to each of drive wheels on left and right sides of the electric truck, each of the drive unit housings 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 the drive wheel. The drive device further includes suspension parts one provided over the final gear in each of the drive unit housings, steering gear parts one being provided over each of the suspension parts, pairs of hinge parts, and pairs of body-connecting parts, one of the pairs connecting each of the steering gear parts to a vehicle body of the electric truck through each of the pairs of hinge parts.

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.

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 flow path control device according to one embodiment includes a first valve, a unit main body and a control valve. The unit main body has an accommodation portion, a first radial communication hole and a side recess portion. The accommodation portion is recessed from a chamber accommodating the oil to cause the first valve to close the first radial communication hole. The side recess portion is recessed from the chamber so as to be continuous to the accommodation portion and not to be continuous to the first radial communication hole. The control valve is movable in the accommodation portion of the unit main body between a position at which a groove of the control valve communicates with the side recess portion and the first radial communication hole and a position at which the groove does not communicate with them.

A flow path control device according to one embodiment includes a first valve, a unit main body and a control valve. The unit main body has an accommodation portion, a first radial communication hole and a side recess portion. The accommodation portion is recessed from a chamber accommodating the oil to cause the first valve to close the first radial communication hole. The side recess portion is recessed from the chamber so as to be continuous to the accommodation portion and not to be continuous to the first radial communication hole. The control valve is movable in the accommodation portion of the unit main body between a position at which a groove of the control valve communicates with the side recess portion and the first radial communication hole and a position at which the groove does not communicate with them.

A flow path control device according to one embodiment includes a first valve which transitions between a closed state where a first flow is closed and an open state where the first flow path is open by moving toward an space from the closed state. The first valve is formed with an axial through-hole that communicates with the first flow path and the space. A pressure-receiving area of the first valve against a jack chamber is smaller than that against the space. Further, a second valve is provided in the space on a second flow path so as to transition between a first state where the axial through-hole is closed and an inflow path oriented toward the space from the jack chamber is open and a second state where it is closed and the axial through-hole is open.

A flow path control device according to one embodiment includes a first valve which transitions between a closed state where a first flow is closed and an open state where the first flow path is open by moving toward an space from the closed state. The first valve is formed with an axial through-hole that communicates with the first flow path and the space. A pressure-receiving area of the first valve against a jack chamber is smaller than that against the space. Further, a second valve is provided in the space on a second flow path so as to transition between a first state where the axial through-hole is closed and an inflow path oriented toward the space from the jack chamber is open and a second state where it is closed and the axial through-hole is open.

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.