Abstract: Provided is a work vehicle capable of reducing the fuel consumption while maintaining the working efficiency. A wheel loader 1 comprising a vehicle body controller 5, 5A for controlling an engine 41, wherein the vehicle body controller 5, 5A limits an upper limit rotational speed of the engine 41 based on an accelerator pedal step-on amount ?, a brake pedal step-on amount ?, a torque converter speed ratio e which is a ratio of a rotational speed of a torque converter 42, a discharge pressure P1 of a loading hydraulic pump 44, and a stroke amount S1 of lift arm cylinders 22 or a stroke amount S2 of a bucket cylinder 24.

Abstract: A make-up/break-out evaluation method that makes it possible to evaluate the seizure resistance of a threaded joint for oil country tubular goods accurately without performing a test using a threaded joint with an actual length. When performing test with respect to the threaded joint for oil country tubular goods formed by attaching a pin lower portion to box upper portion with its axis directed vertically, a test pin formed by a pin shorter than an evaluation target pin used as test pin; a weight attached to test pin upper portion; mass of the weight is equal to or greater than a mass obtained by subtracting the test pin mass from the evaluation target pin mass; an initial set position for test pin is set where test pin five crests or ¼ of all test pin crests, whichever is greater, or more are exposed from the box upper end face.

Abstract: A threaded joint wherein a relationship between shoulder angle parameters and thread taper angle parameters for a coupling and a pair of pins inserted from both ends of the coupling is defined by the following expression (1), and a tightening torque with which the threaded joint is tightened is 60% or more and 85% or less of a yield torque determined by the following expression (2): - 1.5 ? ° ? ? ? ? - ? ? ? ? 2. ° , ( 1 ) T = ( T S + T D ) ? 1 12 ( 2 ) T S = f t ? P c ? E 7 2 ? ( 2 ? ? ? E 7 ) ? L 4 ? 1 2 P c = E ? ? m 2 ? ( ( W 2 ) 2 - ( E 7 2 ) 2 ) ? ( ( E 7 2 ) 2 - ( d 2 ) 2 ) 2 ? ( E 7 2 ) 3 ? ( ( W 2 ) 2 - ( d 2 ) 2 ) T D = Y m ? A S ( P 2 ? ? + R t ? f s cos ? ? + R s ? f s ) .

Abstract: A solid lubricating coating film is used to realize galling resistance equal to or higher than a method using a dope compound regarding lubrication characteristics during make-up/break-out of oil country tubular goods. A threaded joint for oil country tubular goods includes a box having a thread and a pin having a male thread. A lubricating coating film including a solid lubricating coating film forms on a tightening surface of a thread portion of at least one component of the box and pin, the solid lubricating coating film is formed by dispersing a solid lubricant in a binder resin, 90 wt % or more of the binder resin is a polyamideimide resin, an average molecular weight of the polyamideimide resin is 20,000 or more and 40,000 or less, 80 wt % or more of the solid lubricant is polytetrafluoroethylene (PTFE), and an average molecular weight of the PTFE is 30,000 or less.

Abstract: Provided is a loading work vehicle capable of improving work efficiency even when working on a slippery road surface. An HST-traveling-drive wheel loader 1 comprises a step-on amount detection sensor 610, a discharge pressure detection sensor 75, a mode switch device 60, and a controller 5. The controller 5 is configured to: determine whether a limit mode is selected by the mode switch device 60; specify an operation state of the wheel loader 1 when determining that the limit mode is selected; limit maximum traction force to a first set value which is set based on a static friction coefficient ? and vehicle weight when specifying that a bucket 23 is pushed into a natural ground 100; and increase the maximum traction force from the first set value when specifying that excavation of the natural ground 100 is started.

Abstract: To prevent fracture of a box under a tensile load without increasing the outer diameter of the box. The presently disclosed threaded joint for pipes includes a pin provided with a male thread portion at one end of a first pipe, and a box provided with a female thread portion at one end of a second pipe, where each of a plurality of thread grooves of the female thread portion has a corner portion on a load flank side and a corner portion on a stabbing flank side on a thread bottom side, a corner portion on a load flank side of a first thread groove includes a first arc portion that has a first curvature radius, and a second arc portion that has a second curvature radius, and a ratio of the second curvature radius to the first curvature radius is 3 or more.

Abstract: A threaded joint wherein a relationship between shoulder angle parameters and thread taper angle parameters for a coupling and a pair of pins inserted from both ends of the coupling is defined by the following expression (1), and a tightening torque with which the threaded joint is tightened is 60% or more and 85% or less of a yield torque determined by the following expression (2): - 1.5 ? ° ? ? ? ? - ? ? ? ? 2. ° , ( 1 ) T = ( T S + T D ) ? 1 12 ( 2 ) T S = f t ? P c ? E 7 2 ? ( 2 ? ? ? E 7 ) ? L 4 ? 1 2 P c = E ? ? m 2 ? ( ( W 2 ) 2 - ( E 7 2 ) 2 ) ? ( ( E 7 2 ) 2 - ( d 2 ) 2 ) 2 ? ( E 7 2 ) 3 ? ( ( W 2 ) 2 - ( d 2 ) 2 ) T D = Y m ? A S ( P 2 ? ? + R t ? f s cos ? ? + R s ? f s ) .

Abstract: Provided is a work vehicle capable of reducing the fuel consumption while maintaining the working efficiency. A wheel loader 1 comprising a vehicle body controller 5, 5A for controlling an engine 41, wherein the vehicle body controller 5, 5A limits an upper limit rotational speed of the engine 41 based on an accelerator pedal step-on amount ?, a brake pedal step-on amount ?, a torque converter speed ratio e which is a ratio of a rotational speed of a torque converter 42, a discharge pressure P1 of a loading hydraulic pump 44, and a stroke amount S1 of lift arm cylinders 22 or a stroke amount S2 of a bucket cylinder 24.

Abstract: To prevent fracture of a box under a tensile load without increasing the outer diameter of the box. The presently disclosed threaded joint for pipes includes a pin provided with a male thread portion at one end of a first pipe, and a box provided with a female thread portion at one end of a second pipe, where each of a plurality of thread grooves of the female thread portion has a corner portion on a load flank side and a corner portion on a stabbing flank side on a thread bottom side, a corner portion on a load flank side of a first thread groove includes a first arc portion that has a first curvature radius, and a second arc portion that has a second curvature radius, and a ratio of the second curvature radius to the first curvature radius is 3 or more.

Abstract: A screw joint in which an efficient screw length of a joint portion is achieved. This screw joint is for an oil well pipe of an integral type and includes: (i) a pin that is provided with a male screw portion which is a male taper screw, at one end of a steel pipe; and (ii) a box that is provided with a female screw portion which is a female taper screw fitted to the male screw portion, at one end of the steel pipe, in which a structure, in which the pin and the box are in metal contact with each other to seal a fluid, is provided at least at one place of a seal portion on an outer peripheral surface side of a pipe end side of the pin and a seal portion on an inner peripheral surface side of a pipe end side of the box.

Abstract: Provided is a work machine capable of notifying that maintenance is necessary due to continuation of clogging in a cooling device or decrease in cooling performance. A wheel loader 1 including a radiator 31 and an oil cooler 32 comprises a controller 5, 5A configured to determine a clogging continuation state of the radiator 31 or the oil cooler 32. The controller 5, 5A determines whether clogging is occurring in the radiator 31 or the oil cooler 32 based on outside air temperature AW and cooling water temperature CW or hydraulic oil temperature HW, determines whether the clogging continues based on a clogging occurrence ratio R1, R2 while an engine 30 is operating, and outputs a notification command signal for providing the alarm buzzer 61 and the user management system 62 with a command to notify that maintenance is necessary when it is determined that the clogging continues.

Abstract: A threaded joint with excellent tensile strength, comprising: a pin having an externally threaded part comprising a first and second externally threaded sections across a step on an outer periphery on a distal-end side of a first steel pipe or tube; and a box having an internally threaded part comprising a first and second internally threaded sections across the step on an inner periphery on a distal-end side of a second steel pipe or tube, the externally threaded part being screwed to the internally threaded part to join the pin and the box. The threaded joint has a first and second thread sequence with lengths L1 and L2, respectively, and cross-sectional areas P1, P2, B1, and B2 at end positions 4, 5, 6, and 7, respectively, satisfying Formulas (1) and (2): (P2, B2)min?P1/{L1/(L1+L2)}(1) and (P2, B2)min?B1/{L2/(L1+L2)}(2), where (P2, B2)min represents P2 or B2, whichever is smaller.

Abstract: In an unloaded state of the bucket (3), a control device (30) calculates an unloaded moment (M0) around a hinge pin G from the pressure of the lift arm cylinder that is detected by pressure sensors (15a, 15b), the angle of a lift arm that is detected by a lift arm angle sensor 14, and dimension data extracted from a vehicle body information database (35). In a loaded state of the bucket, the control device calculates a loaded moment (M1) around the hinge pin G from the pressure of the lift arm cylinder, the angle of the lift arm, and the dimension data extracted from the vehicle body information database. The control device calculates the load (W) on the bucket by dividing the difference between the unloaded moment and the loaded moment by the horizontal distance (Lw) between the hinge pin and the gravity center position of the bucket.

Abstract: A threaded joint with excellent tensile strength, comprising: a pin having an externally threaded part comprising a first and second externally threaded sections across a step on an outer periphery on a distal-end side of a first steel pipe or tube; and a box having an internally threaded part comprising a first and second internally threaded sections across the step on an inner periphery on a distal-end side of a second steel pipe or tube, the externally threaded part being screwed to the internally threaded part to join the pin and the box. The threaded joint has a first and second thread sequence with lengths L1 and L2, respectively, and cross-sectional areas P1, P2, B1, and B2 at end positions 4, 5, 6, and 7, respectively, satisfying Formulas (1) and (2): (P2, B2)min?P1/{L1/(L1+L2)}(1) and (P2, B2)min?B1/{L2/(L1+L2)}(2), where (P2, B2)min represents P2 or B2, whichever is smaller.

Abstract: Provided is a work machine capable of notifying that maintenance is necessary due to continuation of clogging in a cooling device or decrease in cooling performance. A wheel loader 1 including a radiator 31 and an oil cooler 32 comprises a controller 5, 5A configured to determine a clogging continuation state of the radiator 31 or the oil cooler 32. The controller 5, 5A determines whether clogging is occurring in the radiator 31 or the oil cooler 32 based on outside air temperature AW and cooling water temperature CW or hydraulic oil temperature HW, determines whether the clogging continues based on a clogging occurrence ratio R1, R2 while an engine 30 is operating, and outputs a notification command signal for providing the alarm buzzer 61 and the user management system 62 with a command to notify that maintenance is necessary when it is determined that the clogging continues.

Abstract: A threaded joint for oil well steel pipe is provided. The threaded joint includes a pin provided with a male thread, and a box provided with a female thread threadedly engaged with the male thread, and at an outer periphery side sealing portion, a cross-sectional area S1 of the pin at a seal point, and a cross-sectional area S0 of a pipe body portion, which is an unprocessed pin portion, satisfy an expression (S1/S0)×100?15(%), at an inner periphery side sealing portion, a cross-sectional area S2 of the box at a seal point, and a cross-sectional area S0? of a pipe body portion, which is an unprocessed box portion satisfy an expression (S2/S0?)×100?20(%), and a surface area S3 of a contact portion of an intermediate shoulder between thread rows and the cross-sectional area S0 satisfy the expression (S3/S0)×100?10(%).

Abstract: Provided is a loading work vehicle capable of improving work efficiency even when working on a slippery road surface. An HST-traveling-drive wheel loader 1 comprises a step-on amount detection sensor 610, a discharge pressure detection sensor 75, a mode switch device 60, and a controller 5. The controller 5 is configured to: determine whether a limit mode is selected by the mode switch device 60; specify an operation state of the wheel loader 1 when determining that the limit mode is selected; limit maximum traction force to a first set value which is set based on a static friction coefficient ? and vehicle weight when specifying that a bucket 23 is pushed into a natural ground 100; and increase the maximum traction force from the first set value when specifying that excavation of the natural ground 100 is started.

Abstract: A screw joint in which an efficient screw length of a joint portion is achieved.

Abstract: Provided is a threaded joint for an oil well tubing which possesses sufficient sealability when the external pressure is applied to the threaded joint by suppressing the plastic deformation of a nose portion and sufficient galling resistance. The sufficient galling resistance is provided by preventing the occurrence of galling at the time of making up the threaded joint during verification test performed in accordance with ISO13679:2002 even when the threaded joint for an oil well tubing has a small thickness. Parameters including sizes of the threaded joint at positions of a seal point and shoulder portions satisfy formula 1 ((Ds12?Ds02)/(D12?D02)?0.30), formula 2 (tan ?>(?D+?)/{2(Lt?Ls)}), and Ls/Ln is set to 0.2 to 0.6.

Abstract: A threaded pipe joint, when acted upon by a tensile load, does not break on the female thread-side of a first thread section of a second thread series that extends from an intermediate shoulder. The threaded pipe joint reliably undergoes tensile rupture on the female thread-side of a first thread section of a first thread series, which is the original critical cross-section site. The threaded pipe joint is configured so that when the male and female threads of the intermediate shoulder are screwed together, the load flank-side thread gaps L1G and L2G of a first thread series, which is the radially inward thread series, and a second thread series, which is the radially outward thread series, on the two sides of the intermediate shoulder always satisfy the relationship L1G<L2G.