Abstract: An apparatus for controlling the brake of a vehicle, which easily brings the vehicle to a halt, or starts it, only by the action of the accelerator without operating the brake pedal. Brakes (4,5) are applied when the vehicle speed detected by a speed detector (9) becomes a predetermined threshold value or less. The operation of the brakes (4,5) is turned off when a load detected by a load detector (10) becomes larger than a load operated by a load computer (11,14).

Abstract: A control system designed such that if a heavy load is imposed on a vehicle during running and a hydraulic relief state in which an oil pressure in a hydraulic circuit for a hydrostatic transmission unit exceeds a relief pressure is detected, the angle of a discharge controlling swash plate for a pump is reduced to a specified value (e.g., 50% of the maximum angle) or less, whereby the stall of the vehicle and the overheat of machine parts are prevented.

Abstract: A response control system for a hydrostatic-mechanical transmission. In this system, it is determined in digging/moving operation whether an actual speed ratio which is the ratio of the revolution speed of the output shaft to the revolution speed of the power source is equal to a specified value or less, and if so, a target speed ratio which is a target value for the ratio of the revolution speed of the output shaft to the revolution speed of the power source is set, limiting the amount of change in the target speed ratio per unit time. Based on the target speed ratio thus set, the angle of at least either of discharge controlling swash plates is controlled, thereby reducing vehicle acceleration at the primary stage of digging. In order to slow down the response to a change in load during digging operation, a constant indicating the response to a change in engine revolution is set small in proximity to a target engine revolution speed.

Abstract: A target engine revolution speed is calculated based on the throttle position of an engine such that the amount of change in the target engine revolution speed with respect to time is limited. According to the target engine revolution speed thus calculated, a target motor speed ratio, which is a target value for the ratio of the revolution speed of a motor in a hydrostatic transmission unit to the revolution speed of the engine, is set. With this target motor speed ratio, the angle of at least either of discharge controlling swash plates is adjusted.

Abstract: A turning speed control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle to the right or left; a steering instructing device which can be displaced from a neutral position by operation and which instructs, according to the direction and distance of its displacement, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; and a control unit for performing a control such that when making the turning radius of the vehicle small by increasing the revolution speed of the steering motor according to the displacement of the steering instructing device detected by the displacement detector such that the crawler belts are driven with a relative travel difference therebetwe

Abstract: A control mechanism for a hydrostatic-mechanical power transmission system having a mechanical transmission unit driven through an input shaft connectable to a power source, and a hydrostatic transmission unit that is connectable to the input shaft and includes a pump and a motor each having a displacement setting swash plate. The control mechanism further includes a differential unit for connecting an output shaft to the mechanical transmission unit and the hydrostatic transmission unit to drive. At least either of the displacement setting swash plates is variable in angle.

Abstract: A steering system for use in a track-laying vehicle comprising: a steering motor that is forwardly and reversely rotatable and designed to drive crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a forward/reverse drive state detector for detecting whether the vehicle is in its forward drive state or reverse drive state; a lateral turn instructing device for instructing right turn or left turn of the vehicle; and a steering motor forward/reverse rotation control unit for determining the forward or reverse rotation of the steering motor in accordance with the forward or reverse drive state of the vehicle detected by the forward/reverse drive state detector, such that the vehicle turns to the right or left in response to a right turn instruction or left turn instruction released from the lateral turn instructing device.

Abstract: Upon detection of execution of operation for stopping a vehicle during its running state and of a drop in an actual speed ratio below a predetermined value, the actual speed ratio being the actual ratio of the revolution speed of an output shaft to the revolution speed of a power source, a feedback amount is determined, setting the integral component of the difference between a target motor speed ratio and an actual motor speed ratio to zero. Based on the feedback amount thus determined, an operation amount for controlling the angle of a swash plate is computed. With this amount, the angle of the swash plate is controlled.

Abstract: A control system in which a judgment is made such that (i) a vehicle is in a forward drive control state, on condition that the forward/reverse drive lever is placed in the forward drive position and the actual speed ratio exceeds a specified small value in a forward drive direction, (ii) the vehicle is in a reverse drive control state on condition that the lever is placed in the reverse drive position and the actual speed ratio exceeds a specified small value in a reverse drive direction, (iii) the vehicle is in an engine brake control state, on condition that the lever is placed in the neutral position and the actual speed ratio exceeds the specified small value in the forward or reverse drive direction, (iv) the vehicle is in an FR shift control state, on condition that the lever is placed in the forward or reverse drive position and the actual speed ratio exceeds the specified small value in the reverse or forward drive direction, and (v) the vehicle is in a neutral control state, on condition that the le

Abstract: The maximum value of target motor speed ratio is calculated from the allowable revolution speed of a motor, and based on the maximum value, an allowable value of target speed ratio is set. Target speed ratio is then limited to the allowable value or less. This enables it to prevent overrun occurring e.g., when the vehicle rolls down a hill.

Abstract: A speed change gear control system, wherein gear shift control for shifting the transmission from an arbitrary speed range into a higher speed range which provides higher absolute speed than the arbitrary speed range is performed, provided that the actual speed ratio e of the transmission satisfies .vertline.E.sub.1 .vertline.<.vertline.e.vertline.<.vertline.E.sub.0 .vertline. where E.sub.0 is a speed ratio for a shifting point at which the transmission is shifted from the arbitrary speed range into the higher speed range; and E.sub.1 is a specified speed ratio, or provided that .vertline.e.vertline.+(.DELTA.e/.DELTA.t).times.T.sub.1 >.vertline.E.sub.0 .vertline.-.DELTA.E.sub.1 where .DELTA.e is an increase in the speed ratio e over a period of time .DELTA.t; T.sub.1 is the filling time required for supplying hydraulic oil to a clutch which shifts the transmission from the arbitrary speed range to the higher speed range; and .DELTA.E.sub.1 is a specified small speed ratio.

Abstract: A turning system for use in a track-laying vehicle comprising: a power source; a steering motor driven by the rotation of the power source, for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a power source revolution speed detector for detecting the actual revolution speed of tile power source; and a steering motor control unit for performing a control such that, a target revolution speed set for the steering motor is decreased when the actual revolution speed of the power source detected by the power source revolution speed detector decreases below a target revolution speed set for the power source by a specified revolution speed or more.

Abstract: A turning control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, in accordance with its displacement direction and displacement distance, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; a vehicle speed detector for detecting the vehicle speed at which the vehicle moves forwards or backwards; and a steering motor revolution speed control unit for controlling the revolution speed of the steering motor such that the revolution speed of the steering motor becomes proportional to the vehicle speed detected by the vehicle spee

Abstract: A steering control system for use in a track-laying vehicle comprising: a power source; a steering motor driven by the rotation of the power source, for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, according to the direction and distance of its displacement, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; and a steering motor revolution speed control unit for obtaining a target steering motor revolution speed which is made proportional to the revolution speed of the power source based on the displacement of the steering instructing device detected by the displacement detector and controlling

Abstract: A mechanical - hydraulic transmission for a crawler-type vehicle is provided having a reduced dimension in a widthwise direction perpendicular to input/output shafts and capable of ready installation on an existent crawler steering device. The transmission is arranged such that a power input shaft (1), directly connected to a prime mover, an intermediate shaft (9) and an output shaft (19), are concentrically related and arranged in a longitudinal column. Normal- and reverse-rotation planetary gear devices (5, 6), having respective clutches (7, 8) thereof, are mounted on a periphery of the power input shaft (1), and the power input shaft (1) is connected to a variable displacement hydraulic pump (2).

Abstract: A transmission and control mechanism for a hydrostatic-mechanical power transmission system, provided with a mechanical transmission driven through an input shaft connected to a engine, a hydrostatic transmission connected to the input shaft, and a differential unit for connecting an output shaft to the mechanical and hydrostatic transmissions. The hydrostatic transmission includes a swashplate type pump and motor, with at least one of the swashplates being variable in angle. There is an engine revolution speed sensor, a target motor speed ratio setting device for setting a target motor speed ratio based on whether the engine speed is above, below or within a predetermined speed range, and a swashplate angle controller for controlling the swashplates according to the target motor speed ratio.

Abstract: Disclosed is a clutch changeover circuit suitably used for a multi-stage stationary non-stage transmission. Valve bodies of pressure regulating valves (211, 221, 231, 241) are respectively provided with throttle passages (311, 321, 331, 341) communicating therewith in such a manner that hydraulic oil flows to the clutch sides when they are closed, since the sliding of the clutches or damage thereto can occur if pressure regulating valves having good override characteristics are used. Accordingly, at the time of changing over the clutch, since hydraulic oil flows at least by a portion corresponding to the rate of flow of leaking oil, it is possible to prevent the clutches from sliding or becoming damaged while using regulating valves having good override characteristics.

Abstract: Disclosed is a clutch changeover circuit suitably used for a multi-stage stationary non-stage transmission. Valve bodies of pressure regulating valve (211, 221, 231, 241) are respectively provided with throttle passages (311, 321, 311, 341) communicating therewith in such a manner that hydraulic oil flows to the clutch sides when they are closed, since the sliding of the clutches or damage thereto can occur if pressure regulating valves having good override characteristics are used. Accordingly, at the time of changing over the clutch, since hydraulic oil flows at least by a portion corresponding to the rate of flow of leaking oil, it is possible to prevent the clutches from sliding or becoming damaged while using regulating valves having good override characteristics.

Abstract: A novel speed-change/steering system for crawler type vehicles comprises first and second stepless speed changers and a plurality of planetary gear assemblies disposed along one axis. First and second output shafts of the system are connected to respective elements of any two of the planetary gear assemblies. The input shafts of the first and second stepless speed changers are coupled to a power source, and the output shafts of the first and second stepless speed changers are connected to the planetary gear assemblies. One of the planetary gear assemblies is coupled to the power source. There is provided at least one clutch for fixing at least one element in the planetary gear assemblies. Also there are provided means for connecting elements of adjacent planetary gear assemblies.

Abstract: A turning control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, in accordance with its displacement direction and displacement distance, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; a vehicle speed detector for detecting the vehicle speed at which the vehicle moves forwards or backwards; and a steering motor revolution speed control unit for controlling the revolution speed of the steering motor such that the revolution speed of the steering motor becomes proportional to the vehicle speed detected by the vehicle spee