Abstract: A tractor is provided for suppressing pitching in which a front part of a traveling vehicle body is lifted upward, while a suspension mechanism functions when work is carried out with a ground implement. When a raise control signal for raising the plow is detected in draft control for elevating/lowering the plow based on a draw load value detected by a draw load sensor, mode switching means suppresses or limits the suspension function, via control of the suspension control means to suppress an event in which the front part of the traveling vehicle body is lifted upward. When the raise control signal is not detected, the mode switching means causes the suspension mechanism to function via control of the suspension control means.

Abstract: A drive control system for a work vehicle is provided with a power transmission device that drives front wheels and rear wheels, a request determination unit, and a drive mode control unit. The power transmission device has a drive mode switching mechanism that performs drive mode switching between a four-wheel drive mode in which drive power is transmitted to front wheels and rear wheels and a two-wheel drive mode in which drive power is transmitted to only the rear wheels. The request determination unit determines a necessity for an increase in drive power on a contact area of the work vehicle, and outputs an increase request based on the determination result. The drive mode control unit outputs a drive mode switching request for switching to the four-wheel drive mode to the drive mode switching mechanism, in response to output of the increase request.

Abstract: An exhaust device for a work vehicle including: an exhaust pipe for guiding exhaust to a vehicle exterior. The exhaust pipe includes: an exhaust guide pipe into which exhaust from an engine is introduced, a bending section for changing an exhaust direction; an external protective pipe that externally fits onto a downstream-side guide pipe; an ejector section for suctioning and introducing external air between an outer periphery of the exhaust guide pipe and an inner periphery of the external protective pipe; and an external air introduction section provided to an upstream-side end section of the external protective pipe.

Abstract: An exhaust device for a work vehicle including: an exhaust pipe for guiding exhaust to a vehicle exterior. The exhaust pipe includes: an exhaust guide pipe into which exhaust from an engine is introduced, a bending section for changing an exhaust direction; an external protective pipe that externally fits onto a downstream-side guide pipe; an ejector section for suctioning and introducing external air between an outer periphery of the exhaust guide pipe and an inner periphery of the external protective pipe; and an external air introduction section provided to an upstream-side end section of the external protective pipe.

Abstract: The hydraulic suspension system comprises a suspension mechanism (100) for a traveling vehicle body, a suspension reference position variation mechanism (18) for varying a reference position of a suspension stroke of the suspension mechanism, and a stopped state detector (58) for detecting a state in which operation of the suspension mechanism (100) has stopped. The control management unit (60) controls the suspension reference position variation mechanism (18) so that when operation of the suspension mechanism (100) is detected by the stopped state detector (58) to be in a stopped state, the operation of the suspension mechanism (100) moves toward a target range, in preference to control based on a suspension stroke position obtained from a suspension stroke position sensor (37).

Abstract: A tractor is improved for suppressing pitching in which a front part of a traveling vehicle body is lifted upward, while a suspension mechanism effectively functions when work is carried out with a ground implement. When a raise control signal for raising the plow is detected in draft control for elevating/lowering the plow based on a draw load value detected by a draw load sensor, mode switching means suppresses or limits the suspension function, via control of the suspension control means to suppress an adverse event in which the front part of the traveling vehicle body is lifted upward. When the raise control signal is not detected, the mode switching means causes the suspension mechanism to effectively function via control of the suspension control means.

Abstract: A suspension system for a vehicle includes a swing frame and right and left suspension cylinders for front wheels. The swing frame is swingably supported by the front portion of a vehicle body about a support shaft extending in a lateral direction, and supports the front axle case, so as to allow the front axle case to swing about a center shaft extending in a front-rear direction. The right and left suspension cylinders are provided on the swing frame. A lateral oscillation regulation unit is provided between the swing frame and the front frame, and configured to regulate an oscillation of the swing frame by contact in the lateral direction.

Abstract: A suspension system for a traveling vehicle body is disclosed. The system includes a suspension reference position varying mechanism (18) for varying a reference position of a suspension stroke of the suspension mechanism (100), and a controller (35) configured to calculate an intermediate value from a maximal value corresponding to the maximal position of the suspension stroke and a minimal value corresponding to the minimal position of the suspension stroke, and to control the suspension reference position varying mechanism such that, when the calculated intermediate values deviates from a set target range, the intermediate value is displaced toward the target range. The controller (35) increases a control execution frequency for the suspension reference position varying mechanism (18) when the traveling speed of the vehicle body is low, and reduces the control execution frequency for the suspension reference position varying mechanism (18) when the traveling speed of the vehicle body is high.

Abstract: A hydraulic suspension system includes a suspension base (16) supporting wheels, a hydraulic cylinder (19) for displaceably suspending the suspension base from a vehicle body, and an oil passage connected to the hydraulic cylinder. An accumulator (21, 23) is incorporated within the oil passage. A flow control valve (51) is incorporated at an oil passage portion between the hydraulic cylinder and said accumulator for controlling an amount of work oil flowing therebetween. A pressure sensor (56) is provided for detecting a cylinder oil passage pressure effective on the hydraulic cylinder. A control unit (57) is provided for controlling operation of the flow control valve, based upon a detection value from the pressure sensor.

Abstract: A suspension system for a vehicle includes a swing frame and right and left suspension cylinders for front wheels. The swing frame is swingably supported by the front portion of a vehicle body about a support shaft extending in a lateral direction, and supports the front axle case, so as to allow the front axle case to swing about a center shaft extending in a front-rear direction. The right and left suspension cylinders are provided on the swing frame. A lateral oscillation regulation unit is provided between the swing frame and the front frame, and configured to regulate an oscillation of the swing frame by contact in the lateral direction.

Abstract: Provided are a steel having excellent rolling contact fatigue life and the manufacturing method thereof. The steel consists essentially of 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1% or more and less than 0.5% Mo, 0.010 to 0.050% Al, bymass, and balance of Fe and inevitable impurities, is treated by quenching and tempering, has residual cementite grain sizes ranging from 0.05 to 1.5 ?m, and has prior-austenite grain sizes of 30 ?m or smaller. When the steel is used to bearing steel, the bearing life extends even under service in more severe environments.

Abstract: The hydraulic suspension system comprises a suspension mechanism (100) for a traveling vehicle body, a suspension reference position variation mechanism (18) for varying a reference position of a suspension stroke of the suspension mechanism, and a stopped state detector (58) for detecting a state in which operation of the suspension mechanism (100) has stopped. The control management unit (60) controls the suspension reference position variation mechanism (18) so that when operation of the suspension mechanism (100) is detected by the stopped state detector (58) to be in a stopped state, the operation of the suspension mechanism (100) moves toward a target range, in preference to control based on a suspension stroke position obtained from a suspension stroke position sensor (37).

Abstract: We provide a steel product that includes, by mass %, C: 0.35-0.7%, Si: 0.30-1.1%, Mn: 0.2-2.0%, Al: 0.005-0.25%, Ti: 0.005-0.1%, Mo: 0.05-0.6%, B: 0.0003-0.006%, S: 0.06% or less, P: 0.02% or less, Cr: 0.2% or less, and the balance Fe and inevitable impurities, and has a structure of bainite and/or martensite, the total volume fraction of bainite and martensite being 10% or more, and an induction hardened member that is made of the steel product having a hardened surface layer formed by induction hardening and has a prior austenite grain size of 12 ?m or less through the layer thickness. The member has high fatigue strength and therefore is suitable for an automobile drive shaft, an automobile constant velocity joint or the like.

Abstract: A hydraulic suspension system includes a suspension base (16) supporting wheels, a hydraulic cylinder (19) for displaceably suspending the suspension base from a vehicle body, and an oil passage connected to the hydraulic cylinder. An accumulator (21, 23) is incorporated within the oil passage. A flow control valve (51) is incorporated at an oil passage portion between the hydraulic cylinder and said accumulator for controlling an amount of work oil flowing therebetween. A pressure sensor (56) is provided for detecting a cylinder oil passage pressure effective on the hydraulic cylinder. A control unit (57) is provided for controlling operation of the flow control valve, based upon a detection value from the pressure sensor.

Abstract: There is provided a component for machine structure having a hardened layer through an induction hardening in at least a part thereof, and more improving fatigue strengths as compared with the conventional ones, in which the hardened layer has a hardness Hv of not less than 750 and an average grain size of prior austenite grains is not more than 7 ?m over a full thickness of the hardened layer.

Abstract: A case hardening bearing steel having an excellent rolling contact fatigue life in intermediate temperature, in addition, excellent toughness at room temperature is provided. Specific means for solving the problems are as follows. The composition contains, by mass percent, C of 0.15 to 0.30 mass percent, Si of 0.5 to 2.0 mass percent, Mn of 0.3 to 2.0 mass percent, Cr of 1.3 to 2.5 mass percent, Mo of 0.3 to 1.0 mass percent, and O of not more than 0.0012 mass percent in a range where (Si+Mo)?1.0 mass percent is satisfied, and contains iron and inevitable impurities as remnant; the maximum size of oxide nonmetallic inclusion is not more than 12.5 ?m when examined area is 320 mm2; number of the oxide nonmetallic inclusion having a diameter of equivalent circle of 3 ?m or more is not more than 250 when the examined area is 320 mm2; in addition, C density of an outer layer is adjusted to be in a range from 0.7 to 1.2 mass percent by carburization.

Abstract: The present invention provides a steel material for induction quenching, containing 0.3% to 0.7% of C, 1.1% or less of Si, 0.2% to 1.1% of Mn, 0.05% to 0.6% of Mo, 0.06% or less of S, 0.025% or less of P, 0.25% or less of Al, 0.3% or less of Cr on a mass basis, and the balance being Fe and unavoidable impurities. The steel material has a ferrite structure and a pearlite structure, the total volume fraction of the ferrite structure and the pearlite structure is 90% or more, the thickness of the ferrite structure is 30 ?m or less, and the average prior austenite grain diameter of a hard layer obtained by induction quenching is 12 ?m or less. Since having superior machinability and superior fatigue strength after induction quenching, this steel material is suitable, for an automobile drive shaft, constant velocity joint, and the like.

Abstract: The present invention provides a machine structural part composed of 0.3% to 0.7% of C, 0.30% or less of Si, 0.2% to 2.0% of Mn, 0.005% to 0.25% of Al, 0.005% to 0.1% of Ti, 0.05% to 0.6% of Mo, 0.0003% to 0.006% of B, 0.06% or less of S, 0.020% or less of P, 0.0030% or less of O on a mass basis, and the balance being Fe and unavoidable impurities. In addition, the machine structural part has a hard layer on at least a part of a surface thereof formed by induction quenching, an average prior austenite grain diameter of the hard layer is 7 ?m or less, and the maximum diameter of a non-metal inclusion composed of oxides is 15 ?m or less. Since having a high fatigue strength, this machine structural part is suitable for an automobile drive shaft, constant velocity joint, and the like.

Abstract: The present invention provides a steel product that consists of, by mass %, C: 0.35-0.7%, Si: 0.30-1.1%, Mn: 0.2-2.0%, Al: 0.005-0.25%, Ti: 0.005-0.1%, Mo: 0.05-0.6%, B: 0.0003-0.006%, S: 0.06% or less, P: 0.02% or less, Cr: 0.2% or less, and the balance Fe and inevitable impurities, and has a structure of bainite and/or martensite, the total volume fraction of bainite and martensite being 10% or more, and an induction hardened member that is made of the steel product having a hardened surface layer formed by induction hardening and has a prior austenite grain size of 12 ?m or less through the layer thickness. The member has high fatigue strength and therefore is suitable for an automobile drive shaft, an automobile constant velocity joint or the like.