Driving control apparatus for industrial vehicle

An industrial vehicle comprising:

• an engine;
• a torque converter;
• a transmission coupled to the engine by the torque converter;
• a driving wheel, wherein the driving wheel is rotated by power that is transmitted from the transmission;
• a hydraulic brake for braking the driving wheel, wherein the hydraulic brake generates a braking force, the magnitude of which corresponds to a hydraulic pressure applied to the hydraulic brake;
• a brake valve for adjusting the hydraulic pressure applied to the hydraulic brake;
• a brake actuator, which is moved by a human operator to actuate the hydraulic brake;
• a parking brake located on an output shaft;
• a sensor for detecting the rotational speed of the driving wheel;
• and
• a controller, wherein the controller controls the brake valve such that the hydraulic brake brakes the driving wheel with a force of a normal value, which corresponds to a force applied to the brake actuator, wherein the controller computes the rotational deceleration of the driving wheel while braking based on the detected rotational speed, and wherein, when the computed rotational deceleration exceeds a predetermined deceleration determination value, the controller controls the brake valve such that the braking force of the hydraulic brake is set to a limit value, which is smaller than the normal value,
• wherein, when the vehicle speed is lower than a predetermined determination value, the controller maintains the braking force of the hydraulic brake at the normal value regardless of the rotational deceleration, and
• wherein the parking brake is switched from a non-braking state to a braking state by the controller if the vehicle speed is lower than a predetermined value.

An industrial vehicle comprising:

• an engine;
• a torque converter;
• a transmission coupled to the engine by the torque converter;
• a driving wheel, wherein the driving wheel is rotated by power that is transmitted from the transmission;
• a hydraulic brake for braking the driving wheel, wherein the hydraulic brake generates a braking force, the magnitude of which corresponds to a hydraulic pressure applied to the hydraulic brake;
• a brake valve for adjusting the hydraulic pressure applied to the hydraulic brake;
• a brake actuator, which is moved by a human operator to actuate the hydraulic brake;
• a sensor for detecting the rotational speed of the driving wheel;
• and
• a controller, wherein the controller controls the brake valve such that the hydraulic brake brakes the driving wheel with a force of a normal value, which corresponds to a force applied to the brake actuator, wherein the controller computes the rotational deceleration of the driving wheel while braking based on the detected rotational speed, and wherein, when the computed rotational deceleration exceeds a predetermined deceleration determination value, the controller controls the brake valve such that the braking force of the hydraulic brake is set to a limit value, which is smaller than the normal value,
• wherein the controller controls the brake valve such that the braking force of the hydraulic brake is increased to the normal value after being decreased to the limit value, and
• wherein the normal value of the braking force is gradually decreased each time the braking force is increased to the normal value from the limit value.

An industrial vehicle comprising:

• an engine;
• a torque converter;
• a transmission coupled to the engine by the torque converter;
• a driving wheel, wherein the driving wheel is rotated by power that is transmitted from the transmission;
• a hydraulic brake located in a power transmission path between the torque converter and the driving wheel to brake the driving wheel, wherein the hydraulic brake generates a braking force, the magnitude of which corresponds to a hydraulic pressure applied to the hydraulic brake;
• a brake valve for adjusting the hydraulic pressure applied to the hydraulic brake;
• a brake actuator, which is moved by a human operator to actuate the hydraulic brake;
• a sensor for detecting the rotational speed of the driving wheel;
• a controller, wherein the controller controls the brake valve such that the hydraulic brake brakes the driving wheel with a force of a normal value, which corresponds to a force applied to the brake actuator, wherein the controller computes the rotational deceleration of the driving wheel while braking based on the detected rotational speed, and wherein, when the computed rotational deceleration exceeds a predetermined deceleration determination value, the controller controls the brake valve such that the braking force of the hydraulic brake is set to a limit value, which is smaller than the normal value;
• and
• a wheel brake located at the driving wheel to directly brake the driving wheel in response to actuation of the brake actuator.

An industrial vehicle comprising:

• an engine;
• a torque converter;
• a transmission coupled to the engine by the torque converter, wherein the transmission includes a hydraulic forward clutch, which is engaged when the vehicle is moving forward, and a hydraulic reverse clutch, which is engaged when the vehicle is moving backward, and wherein each clutch produces an engaging force, the magnitude of which corresponds to a hydraulic pressure applied to the clutch;
• a driving wheel, wherein the driving wheel is rotated by power that is transmitted from the transmission;
• a hydraulic brake for braking the driving wheel, wherein the hydraulic brake generates a braking force, the magnitude of which corresponds to a hydraulic pressure applied to the hydraulic brake;
• a brake valve for adjusting the hydraulic pressure applied to the hydraulic brake;
• a brake actuator, which is moved by a human operator to actuate the hydraulic brake;
• a sensor for detecting the rotational speed of the driving wheel;
• a controller, wherein the controller controls the brake valve such that the hydraulic brake brakes the driving wheel with a force of a normal value, which corresponds to a force applied to the brake actuator, wherein the controller computes the rotational deceleration of the driving wheel while braking based on the detected rotational speed, and wherein, when the computed rotational deceleration exceeds a predetermined deceleration determination value, the controller controls the brake valve such that the braking force of the hydraulic brake is set to a limit value, which is smaller than the normal value;
• a forward clutch valve for adjusting a hydraulic pressure applied to the forward clutch;
• a reverse clutch valve for adjusting a hydraulic pressure applied to the reverse clutch;
• and
• a shift actuator, which is shifted between a forward position for moving the vehicle forward and a reverse position for moving the vehicle backward, wherein, when the shift actuator is shifted to the forward position, the controller controls the forward clutch valve to engage the forward clutch, and when the shift actuator is shifted to the reverse position, the controller controls the reverse clutch valve to engage the reverse clutch, and wherein, when direction switching is performed, in which the shift actuator is moved from the forward position to the reverse position or from the reverse position to the forward position while the vehicle is moving, the controller executes a vehicle deceleration control procedure for switching the moving direction of the vehicle, wherein during the vehicle deceleration control procedure, the controller limits the engine speed to be equal to or lower than a predetermined upper limit value.