Abstract: A cup-type strain wave gearing having a unit structure and having: a stationary-side part including a unit housing and an internally toothed gear; a driving-side part including an output member and an externally toothed gear; and a sliding bearing supporting the stationary-side part and the driving-side part in the radial direction and the thrust direction in a state in which relative rotation is possible. The sliding bearing has a cylindrical bushing accommodated in a radial gap, and annular bushings accommodated respectively in thrust gaps. Thus, it is possible to provide an advantageous strain wave gearing having a unit structure that is more lightweight and compact than when a rolling bearing is used.

Abstract: When a strain wave gearing is used in an application for an operation of repeating startup/stopping, an outer-side lubrication portion and an inner-side lubrication portion, which are lubricated using different types of grease, remain in a communicating state without being divided using a seal member or the like. The outer-side lubrication portion is supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Similarly, the inner-side lubrication portion is also supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Essentially, the outer-side lubrication portion and the inner-side lubrication portion can be lubricated appropriately using different types of grease, without the grease becoming mixed.

Abstract: An externally toothed gear of a dual-type strain wave gearing is provided with first and second external teeth having different teeth numbers, and a gap formed between these teeth as a cutter clearance area for tooth cutters. Where L1 is the maximum width of the gap, t1 is a depth from the tooth top land of the first external teeth to the deepest part of the gap, h1 is the tooth depth of the first external teeth, t2 is a depth from the tooth top land of the second external teeth to the deepest part, and h2 is the tooth depth of the second external teeth, any one of the following conditions 1 to 3 is satisfied: L1=0.1L?0.35L, t1=0.9h1?1.3h1, and t2=0.3h2?0.9h2??Condition 1: L1=0.1L?0.35L, t1=0.3h1?0.9h1, and t2=0.9h2?1.3h2??Condition 2: L1=0.1L?0.35L, t1=0.3h1?0.9h1, and t2=0.3h2?0.9h2??Condition 3: It is possible to obtain a dual-type strain wave gearing in which wear resistance and tooth bottom fatigue strength are increased.

Abstract: In this optical rotary encoder, detection tracks of a rotating disc are irradiated with detection light emitted from a light-emitting element. An optical signal obtained via slits in the detection tracks passes through a slit pattern in a fixed slit plate and is received by light-receiving surfaces of a light-receiving element. The slit pattern in the fixed slit plate is formed so as to fit into a range of an effective spot of the detection light. An LED or other light-emitting element that has a small effective spot diameter can be used, which is advantageous in terms of reducing costs and making the device more compact.

Abstract: A strain wave gearing unit has a unit housing, a strain wave gearing, and a bearing device. Balls of a bearing part of the bearing device are positioned on the diametrically outer side with respect to a cylindrical barrel part of an externally toothed gear. The diameter S of the balls is 0.05 to 0.15 times the pitch diameter D of the externally toothed gear. The centers of the balls are positioned between a point at a distance of 1.2 times the diameter S toward the cylindrical-barrel-part side from an inner-side end surface of a diaphragm along a center axis and a point at a distance of 1 times the diameter S toward a side opposite the cylindrical barrel part from the inner-side end surface. The bearing device can be configured to be used in common for strain wave gearing units having different axial lengths.

Abstract: A unit-type strain wave gearing device provided with a cross roller bearing that supports an internally toothed gear and an externally toothed gear in a state in which both gears can rotate relative to each other, and a meshing section of both gears is lubricated with grease. A gap by which the meshing section and the cross roller bearing raceway groove communicate is formed between the inner ring of the cross roller bearing and the external gear. Due to the pump effect caused by deflection of the external gear, grease is pushed from the meshing section to the gap. Some grease is returned to the inner space of the externally toothed gear via a grease-flowing hole that penetrates the diaphragm of the external gear. Thus, leakage of grease from an oil seal of the cross roller bearing to the unit side can be controlled.

Abstract: An outer-ring lubrication groove pattern formed in an outer-race raceway surface and an inner-race lubrication groove pattern formed in an inner-race raceway surface of a wave generator bearing of a strain wave gearing device are patterns in which linear lubrication grooves having very small widths and depths of several micrometers or less are arranged at fine pitches of several micrometers or less. The inner-race lubrication groove pattern includes a second groove pattern formed in long-axis-side inner-race raceway surface portions to hold the lubricant, and a first groove pattern formed in short-axis-side inner-race raceway surface portions to hold the lubricant and guide the lubricant to the second groove pattern. This configuration improves the contact state between balls and the inner-race and outer-race raceway surfaces of the wave generator bearing, thus reducing the coefficient of friction therebetween.

Abstract: The tooth profile contours of a rigid internally toothed gear and a flexible externally toothed gear in this strain wave gearing are stipulated by: meshing portions which each mesh with the opposing gear; tooth-crest-side convex surface portions which, respectively, are smoothly connected to the addendum-side ends of the meshing portions and extend from said ends to the apices of the tooth crests; and tooth-bottom-side concave surface portions which, respectively, are smoothly connected to the dedendum-side ends of the meshing portions and extend from said ends to the deepest parts of the tooth bottoms. The meshing portions and tooth-crest-side convex surface portions are machined portions that are simultaneously machined by topping gear cutting, and there are no edges on the teeth of either gear on the tooth-crest side.

Abstract: In a unit-type strain wave gearing, a rotating-side member, which is constituted by a second internally toothed gear and an output shaft is supported, via a first sliding bearing and a second sliding bearing, on a fixed-side member so as to be capable of relative rotation, the fixed-side member being constituted by a unit housing and a first internally toothed gear. Sliding bearing surfaces of the first sliding bearing and sliding bearing surfaces of the second sliding bearing are defined by a conic surface having a central axis line as a center line. It is possible to realize a unit-type strain wave gearing which is advantageous in making smaller and more compact than when a roller bearing is used. It is also easier to adjust the gap between the sliding bearing surfaces because a radial sliding bearing having no function to adjust the radial gap is obviated.

Abstract: In a strain wave gearing device, fine first and second lubricant-holding grooves for holding lubricant are formed at fine pitches in an outer-race external peripheral surface of a wave generator bearing and an outer-race-contacting internal peripheral surface portion of an externally toothed gear in contact therewith. Fine lubricant-guiding grooves for guiding the lubricant to the outer-race-contacting internal peripheral surface portion are formed at fine pitches in a second internal peripheral surface portion, which adjoins the outer-race-contacting internal peripheral surface portion, of an internal peripheral surface of the externally toothed gear. This configuration improves the contact state between the outer-race-contacting internal peripheral surface portion of the externally toothed gear and the outer-race external peripheral surface, thus suppressing fretting wear occurring in these surfaces.

Abstract: A strain wave gearing has a wave generator provided with a rigid plug and a wave bearing. The wave bearing is of a deep groove bearing type and is mounted on an elliptical outer circumferential surface of the rigid plug, whereby outer race and inner race thereof are flexed into an elliptical shape. Where D is a ball diameter of the balls, Ro is a raceway-surface radius of the outer race, Ri is a raceway-surface radius of the inner race, Ro/D is an outer-race conformity, and Ri/D is an inner-race conformity, the outer-race conformity Ro/D is greater than the inner-race conformity Ri/D. The friction torque of the wave bearing can be reduced while maintaining the practical service life thereof to be the same level as in a conventional one.

Abstract: A strain wave gearing has a wave generator which flexes an externally toothed gear in a radial direction to form meshing portions thereof with an internally toothed gear in positions that are separated along a circumferential direction of the externally toothed gear. When the wave generator rotates, the meshing portions move in the circumferential direction. Non-meshing regions are formed in part of the meshing portions along the tooth trace direction thereof. The non-meshing regions are those of a prescribed width including the support center of a wave bearing in the tooth trace direction. The concentration of stress in the tooth root of the externally toothed gear can be alleviated, and the tooth-root fatigue strength of the externally toothed gear can be increased.

Abstract: An exemplary encoder assembly includes a substrate, a first encoder, and a second encoder. The substrate has two or more position sensors, each position sensor being configured for detecting a rotary position of a shaft or other rotating element of a machine. The first encoder includes at least one first position sensor of the two or more position sensors. The at least one first position sensor is disposed on the substrate for off-axis alignment with the shaft or other rotating element of the machine. The second encoder includes a second position sensor of the two or more position sensors, the second position sensor being disposed on the substrate for on-axis or off-axis alignment with the shaft or other rotating element of the machine. Each position sensor is configured to detect different or common signal types, and a signal type of the second position sensor excludes optical signals.

Abstract: A strain wave gearing wherein the outer circumferential surface of an outer ring of a wave generator is in contact with an inner-circumferential-surface portion of a flexible externally toothed gear, and a release groove, which is not in contact with the outer circumferential surface, is formed in the inner-circumferential-surface portion. The release groove is formed in a region containing a ball raceway groove. The groove depth of the release groove gradually increases from both sides of the groove in the groove width direction toward a deepest portion of the groove provided at an intermediate portion in the groove width direction. By providing the release groove, it is possible to smooth the distribution of pressing force of the wave generator acting on the externally toothed gear in the tooth-trace direction. In addition, the tooth root fatigue strength and the transmission torque capacity of the externally toothed gear can be improved.

Abstract: A cup-shaped strain wave gearing has an externally toothed gear formed with a cylindrical extension portion extending from an end of an external tooth forming portion of the externally toothed gear. A space between the external peripheral surface of the cylindrical extension portion and an end face of an internally toothed gear is sealed by an oil seal. A space between an outer-side lubrication portion on the outer side of the externally toothed gear and an inner-side lubrication portion on the inner side of the externally toothed gear is blocked by a lubricant-mixing-prevention part configured from the cylindrical extension portion and the oil seal. The mixing of different types of lubricants supplied to the outer-side and inner-side lubrication portions can be effectively prevented.

Abstract: An externally toothed gear of a dual-type strain wave gearing is provided with first and second external teeth having different teeth numbers, and a gap formed between these teeth as a cutter clearance area for tooth cutters. The maximum width L1 of the gap is 0.1 to 0.3 times the width L of the externally toothed gear. The depth from the tooth top land of the first external teeth to the deepest part of the gap is 0.9 to 1.3 times the depth of the first external teeth, and the depth from the tooth top land of the second external teeth to the deepest part of the gap is 0.9 to 1.3 times the depth of the second external teeth. The tooth bottom fatigue strength of the externally toothed gear provided with differing numbers of first and second external teeth is increased.

Abstract: A hollow strain-wave gear device (1) has a wave generator (5), a wave generator plug (5a) of which is integrally formed in a portion of a hollow rotating shaft (6). A plug reinforcement part (5d), which is adjacent to the wave generator plug (5a), has a thickness larger than that of the wave generator plug (5a), and is integrally formed in the hollow rotating shaft (6). The wave generator plug (5a) is reinforced by the highly rigid plug reinforcement part (5d) formed adjacently to the wave generator plug (5a). It is thus possible to prevent or suppress a decline in the rigidity of the wave generator plug (5a) when the hollow rotating shaft has a thin thickness in order to reduce the weight of the hollow rotating shaft (6) and increase the diameter of the hollow portion thereof. Consequently, it is possible to suppress a decline in ratcheting torque.

Abstract: When a strain wave gearing is used in an application for an operation of repeating startup/stopping, an outer-side lubrication portion and an inner-side lubrication portion, which are lubricated using different types of grease, remain in a communicating state without being divided using a seal member or the like. The outer-side lubrication portion is supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Similarly, the inner-side lubrication portion is also supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Essentially, the outer-side lubrication portion and the inner-side lubrication portion can be lubricated appropriately using different types of grease, without the grease becoming mixed.

Abstract: A double-row cylindrical roller bearing employs a cross roller bearing for one cylindrical roller bearing and a parallel cylindrical roller bearing for the other cylindrical roller bearing. The relative positions of a first cylindrical roller on the cross roller bearing part side and a second cylindrical roller on the parallel cylindrical roller bearing part side are not restricted in the direction of the bearing center axis lines thereof. As a result, a bearing having high rigidity and being easy to process and assemble can be achieved at low cost. Increase in friction torque in bearing sliding sections and fluctuation in bearing properties can also be suppressed.

Abstract: A double-row cylindrical roller bearing employs a cross roller bearing for one cylindrical roller bearing and a parallel cylindrical roller bearing for the other cylindrical roller bearing. The relative positions of a first cylindrical roller on the cross roller bearing part side and a second cylindrical roller on the parallel cylindrical roller bearing part side are not restricted in the direction of the bearing center axis lines thereof. As a result, a bearing having high rigidity and being easy to process and assemble can be achieved at low cost. Increase in friction torque in bearing sliding sections and fluctuation in bearing properties can also be suppressed.