Abstract: A axial flow fan includes an impeller having a plurality of blades, a motor arranged to rotate the impeller, and a casing accommodating the impeller and the motor. The casing includes a cylindrical housing, a motor base configured to hold the motor, and a plurality of spokes connecting the housing with the motor base. The plurality of spokes include a spoke having a straight shape and a spoke having a curved shape that is convex toward a rotational direction of the impeller. The axial flow fan further includes a lead wire for supplying electric power to the motor. When a radial length of the spoke having the straight shape is defined as L and an amount of the curvature of the spoke having the curved shape is defined as X, a displacement of the curved shape (X/L) is less than 0.2.

Abstract: A numerical control device with a function to prevent a problem caused by a rapid stop of a processing operation due to a motor overheating during processing. A temperature comparator obtains a load ratio T/Tmax or Tw/Tmax which is a ratio of the motor temperature T or predicted temperature Tw to a maximum allowable temperature Tmax stored in a storage device. When the load ratio T/Tmax or Tw/Tmax is over a threshold Tp stored in a storage, the device is placed in an alarm mode to shutdown the power supply to the motor after the processing program is executed to the end of a sequence block or the end of the processing program.

Abstract: A numerical control device with a function to prevent a problem caused by a rapid stop of a processing operation due to a motor overheating during processing. A temperature comparator obtains a load ratio T/Tmax or Tw/Tmax which is a ratio of the motor temperature T or predicted temperature Tw to a maximum allowable temperature Tmax stored in a storage device. When the load ratio T/Tmax or Tw/Tmax is over a threshold Tp stored in a storage, the device is placed in an alarm mode to shutdown the power supply to the motor after the processing program is executed to the end of a sequence block or the end of the processing program.

Abstract: A fan device includes a rotor 20 and recesses 40 to be filled with claylike weights 70. The rotor 20 includes an impeller 23 and a shaft 10. The impeller 23 has a hub 21 and vanes 22. The recesses 40 are provided on a surface 212 that crosses an axial direction of the hub 21. Each recess 40 has a first area 41 and a second area 42. The first area 41 is circumferentially arranged and extends in a substantially circumferential direction. The second area 42 is connected to an outer circumferential side of the first area 41 and has a shorter length in the circumferential direction than the first area 41. The weight 70 is closely adhered to wall surfaces 421 and 422 formed along a radial direction in the second area 42 so as to prevent separation thereof.

Abstract: In a linear motor used for a driving axis of a large-size machine tool having a very long driving stroke, pole position correction values at a plurality of stroke positions are stored in a memory. A pole position correction value corresponding to an actual stroke position of a slider is calculated based on the stored pole position correction value. A corrected electrical angle offset value derived based on the calculated pole position correction value is used to control the linear motor.

Abstract: An axial fan is provided. The axial fan includes a hub, an impeller having a plurality of blades mounted on an outer peripheral surface of the hub, and a housing surrounding the impeller. Each of the blades has a front edge angle (?) within a range of ?8° to ?20°, a mounting angle (?) within a range of 36° to 50°, and a twisted angle (?) within a range of 10°±2°.

Abstract: A structure that rigidly connects a shaft and a hub in a fan device with a motor, ensuring the squareness of the shaft in relation to the hub, and not worsening the flowability of the resin that constitutes the hub during injection molding, is provided. The fan device includes an approximately cylindrical hub 117 with a bottom and made of resin, vanes 118 positioned at an outer circumference of the hub 117, a shaft 113 attached to the bottom of the hub 117, and a reinforcing plate 115 for reinforcing the bottom of the hub 117. The shaft 113 is connected to the reinforcing plate 115, and a through hole 115b filled with the resin for making the hub 117 is provided on the reinforcing plate.

Abstract: The present invention provide an axial flow fan which comprises an impeller having a plurality of blades, a motor arranged to rotate the impeller, a casing accommodating the impeller and the motor, and a lead wire for supplying electric power to the motor, wherein the casing comprises a cylindrical housing, a motor base installing the motor, and a plurality of spokes connecting the housing with the motor base, and wherein the plurality of spokes include a spoke having a straight shape and a spoke having a curved shape convexly toward a rotational direction of the impeller.

Abstract: A motor magnetic pole position correction method includes preventing a movement of a movable element of a direct drive motor by mechanical brake (step S9), generating a command that designates a position spaced or separated from the present position (step S10), detecting a torque command value of the direct drive motor (step S12), determining a magnetic pole position correction value based on a comparison between the detected torque command value and a predetermined threshold value (steps S14 and S16), storing the determined magnetic pole position correction value in a memory (step S18), and performing motor control using an electrical angle offset value obtained based on the magnetic pole position correction value stored in the memory.

Abstract: A motor magnetic pole position correction method includes preventing a movement of a movable element of a direct drive motor by mechanical brake (step S9), generating a command that designates a position spaced or separated from the present position (step S10), detecting a torque command value of the direct drive motor (step S12), determining a magnetic pole position correction value based on a comparison between the detected torque command value and a predetermined threshold value (steps S14 and S16), storing the determined magnetic pole position correction value in a memory (step S18), and performing motor control using an electrical angle offset value obtained based on the magnetic pole position correction value stored in the memory.

Abstract: The present invention provides a magnetic attractive force-offsetting linear motor which prevents motor thrust from varying due to changes in the position on a stator, thus enabling improvement of the motor thrust and of the accuracy of the machine tool and the quality of a processed surface. A magnetic attractive force offsetting linear motor has a base 72 that fix stators 52a and 52b by contacting stator bottom surfaces 74, two stator mounting members each provided on a side of a corresponding one of the stators 52a and 52b and each extending from the base 72 to a height substantially equal to that of a stator top surface 73, and two plate-like support members 81 fixedly connected to the stator top surfaces of the respective two stators 52a and 52b and to a base top surface 84.

Abstract: An axial fan is provided. The axial fan includes a hub, an impeller having a plurality of blades mounted on an outer peripheral surface of the hub, and a housing surrounding the impeller. Each of the blades has a front edge angle (?) within a range of ?8° to ?20°, a mounting angle (?) within a range of 36° to 50°, and a twisted angle (?) within a range of 10°±2°.

Abstract: A linear motor assembly includes two stators extending in parallel and having salient poles arranged at a predetermined interval on opposing surfaces and a mover having three types of mover blocks. The mover blocks are made up of three-phase alternating current coils configuring magnetic poles of three phases and permanent magnets arranged in alternating polarities on two surfaces of the mover blocks opposing each of the two stators. The mover blocks are movable between the two stators along a direction in which the stators extend. A plurality of linear motors are arranged in parallel with respect to a travel direction of the movers, and the stators provided between adjacent movers are integrally formed such that they have said salient poles on the two surfaces opposing these movers.

Abstract: In a linear motor, the stators and sliders are arranged to fill a predetermined relationship. In one configuration, two stators each include a plurality of stator blocks arranged in a moving direction of sliders so that projecting poles are maintained at predetermined intervals. Boundary surfaces are formed in adjacent stator blocks so as to be displaced relative to one another between the two opposite blocks by a distance Ld in the moving direction of the sliders. When a distance between end surface of the slider blocks is defined as L and the overall length of one stator block is defined as L0, the components are arranged such that Ld>L/3 and (L0?Ld)>L/3.

Abstract: There had been a problem that the installation area of a linear motor becomes large when a plurality of linear motors are arranged in parallel in the travel direction of a mover. In the present linear motor, stators provided between adjacent movers 51a, 51b are integrally formed. The integrally formed stator 52c has salient poles 50 on each of the two surfaces opposing the movers 51a, 51b. As a result, installation area may be reduced compared to a case where a plurality of linear motors are simply arranged in parallel with respect to the travel direction of the mover.

Abstract: The present invention provides a magnetic attractive force-offsetting linear motor which prevents motor thrust from varying due to changes in the position on a stator, thus enabling improvement of the motor thrust and of the accuracy of the machine tool and the quality of a processed surface. A magnetic attractive force offsetting linear motor has a base 72 that fix stators 52a and 52b by contacting stator bottom surfaces 74, two stator mounting members each provided on a side of a corresponding one of the stators 52a and 52b and each extending from the base 72 to a height substantially equal to that of a stator top surface 73, and two plate-like support members 81 fixedly connected to the stator top surfaces of the respective two stators 52a and 52b and to a base top surface 84.

Abstract: A linear motor having a more preferable braking function is realized with a low cost. A linear motor has a slider and a stator. A driving winding is wound around the slider. A plurality of permanent magnets forming magnetic poles which invert at a predetermined period are provided on a surface of the slider opposing the stator. Teeth are formed on the stator with a predetermined spacing therebetween. The stator extends to a region outside of an effective movable range, and a braking winding is wound around the teeth in the extended portion. When the slider moves into a region outside of the effective movable range, an induced voltage is generated in the braking winding and a current flows. A thrust in a direction opposite to the movement direction of the slider is generated by the current.

Abstract: In a linear motor, the stators and sliders are arranged to fill a predetermined relationship. In one configuration, two stators each include a plurality of stator blocks arranged in a moving direction of sliders so that projecting poles are maintained at predetermined intervals. Boundary surfaces are formed in adjacent stator blocks so as to be displaced relative to one another between the two opposite blocks by a distance Ld in the moving direction of the sliders. When a distance between end surface of the slider blocks is defined as L and the overall length of one stator block is defined as L0, the components are arranged such that Ld>L/3 and (L0?Ld)>L/3.

Abstract: A linear motor having a more preferable braking function is realized with a low cost. A linear motor has a slider and a stator. A driving winding is wound around the slider. A plurality of permanent magnets forming magnetic poles which invert at a predetermined period are provided on a surface of the slider opposing the stator. Teeth are formed on the stator with a predetermined spacing therebetween. The stator extends to a region outside of an effective movable range, and a braking winding is wound around the teeth in the extended portion. When the slider moves into a region outside of the effective movable range, an induced voltage is generated in the braking winding and a current flows. A thrust in a direction opposite to the movement direction of the slider is generated by the current.