Abstract: In order to provide an optical module capable of detecting a frequency variation at higher accuracy, an optical module includes a light source that outputs light, a first splitter that splits the light, a band filter that transmits one piece of light split by the first splitter with a periodic frequency characteristic, a transmitted-light detector that detects transmitted-light intensity transmitted through the band filter, a variation device that varies the transmitted-light intensity in a first direction, by varying a parameter of a signal being input to the light source, and a frequency variation detection device that detects a frequency variation of the light from the light source, when a variation of the transmitted-light intensity in a second direction being opposite to the first direction is detected, in a case where the variation device varies the parameter from the first value to the second value.

Abstract: A boot for constant-velocity universal joint comprises a major-diameter cylindrical portion 2, a minor-diameter cylindrical portion 3 being separated away from and being put in place concentrically with the major-diameter cylinder portion 2, and having a smaller diameter than that of the major-diameter cylindrical portion 2, and an intermediate portion 10 connecting the major-diameter cylindrical portion 2 with the minor-diameter cylindrical portion 3. The intermediate portion 10 comprises a stretchable bellows portion 19 being connected with the minor-diameter cylindrical portion 3 integrally, and a rigidity-producing portion 11 being connected with the bellows portion 19 and the major-diameter cylindrical portion 2 integrally. The rigidity-producing portion 11 enlarges diametrically from the bellows portion 19 toward the major-diameter cylindrical portion 2, and additionally at least an outer peripheral surface 101 of the rigidity-producing portion 11 has a plurality of shoulders 61 in a stepwise manner.

Abstract: A cross groove type constant velocity joint 10 comprises a cuplike outer race 11, an inner race 12, plural balls 13 and a cage 14. The outer race 11 has plural outer grooves 11a twisting about a rotational axis of the outer race 11 on its inner surface. The outer race 11 itself has plural restrictions 11b at the back of the outer grooves 11a to prevent the balls 13 from dropping out of the outer grooves 11a where the respective ball 13 is at the innermost end of the outer groove 11a.

Abstract: A boot for constant-velocity universal joint comprises a major-diameter cylindrical portion 2, a minor-diameter cylindrical portion 3 being separated away from and being put in place concentrically with the major-diameter cylinder portion 2, and having a smaller diameter than that of the major-diameter cylindrical portion 2, and an intermediate portion 10 connecting the major-diameter cylindrical portion 2 with the minor-diameter cylindrical portion 3. The intermediate portion 10 comprises a stretchable bellows portion 19 being connected with the minor-diameter cylindrical portion 3 integrally, and a rigidity-producing portion 11 being connected with the bellows portion 19 and the major-diameter cylindrical portion 2 integrally. The rigidity-producing portion 11 enlarges diametrically from the bellows portion 19 toward the major-diameter cylindrical portion 2, and additionally at least an outer peripheral surface 101 of the rigidity-producing portion 11 has a plurality of shoulders 61 in a stepwise manner.

Abstract: A cross groove type constant velocity joint 10 comprises a cuplike outer race 11, an inner race 12, plural balls 13 and a cage 14. The outer race 11 has plural outer grooves 11a twisting about a rotational axis of the outer race 11 on its inner surface. The outer race 11 itself has plural restrictions 11b at the back of the outer grooves 11a to prevent the balls 13 from dropping out of the outer grooves 11a where the respective ball 13 is at the innermost end of the outer groove 11a.

Abstract: A power transmission device is provided to improve sealing performance by reducing change in a surface pressure of sealing parts between power transmission shafts and boots. A first cylinder part of a boot is made from thermoplastic elastomer. A thickness Ta of the first cylinder part ranges from 1 mm to 2 mm, and a crimping allowance of the first cylinder part by a clamp member ranges from 0.1 mm to 0.5 mm. A width Wa of a first engaging groove formed at a power transmission shaft is equal to or greater than 20 percents of an axial width Wb of the clamp member. An axial distance from an end of the clamp member, near a bellows part, to an edge portion of the first engaging groove, near the bellows part, is in the range between 42.5 percents to 100 percents of the axial width Wb of the clamp member.

Abstract: A grease composition for use in ball type constant velocity joints, which comprises the following components a base oil; a diurea thickener of the formula: R1—NH—CO—NH—C6H4-p-CH2—C6H4-p-NH—CO—NHR2 wherein R1 and R2 are alkyl groups having 8 carbon atoms, molybdenum disulfide; molybdenum dithiocarbamate of the formula: (R3R4N—CS—S)2—Mo2OmSn wherein R3 and R4 independently represent an alkyl group having 1 to 24 carbon atoms, m is 0 to 3, n is 4 to 1 and m+n=4, calcium salts or overbasic calcium salts of petroleum sulfonates, sulfur-phosphorus extreme pressure agent, and castor oil. The grease composition exhibits excellent wear-resistance and pitting-inhibitory effect.

Abstract: A DC motor drive circuit includes a position detector for producing an output signal that corresponds to a rotational position of the rotor, a current controller for controlling current supply to the winding in accordance with the output signal of the position detector, and a phase advancing portion for the current between the position detecting portion and the current controller, so that the timing for supplying current to the winding is advanced and efficiency of converting the current supplied to the winding into a motor torque is improved.

Abstract: A DC motor drive circuit includes a position detector for producing an output signal that corresponds to a rotational position of the rotor, a current controller for controlling current supply to the winding in accordance with the output signal of the position detector, and a phase advancing portion for the current between the position detecting portion and the current controller, so that the timing for supplying current to the winding is advanced and efficiency of converting the current supplied to the winding into a motor torque is improved.