365 results about "Axial rigidity" patented technology

A device for use within an occluded biological vessel and a method of using same to remove occlusion material from a vessel are provided. The device includes an elongated body configured for delivering projections arranged around a distal portion thereof into the biological vessel. Each of the projections includes a leaf-like structure connected to a stem portion having a higher axial rigidity than the leaf-like structure.

The bone screw has a head, a shaft and a longitudinal axis. The shaft comprises a proximal section adjacent to the head and a distal section secured to the proximal section by a cardan or cardan-like joint, the distal section being suitable for introduction into the bone and being provided with an outer thread. The bone screw can be bent in all directions relative to its longitudinal axis, while retaining its axial rigidity and fully transmitting a couple without the need for additional means.

The invention belongs to the technical field of strength tests in aviation, and particularly relates to a test device capable of evenly applying an axial compression load and a shearing load. The test device comprises a shearing load applying component 1, an axial compression load applying component 2, a lower platform component 3 and a rib-adding flat plate component 4. According to the technology for independently loading the compression load and the shearing load, adopted by the device, the device not only is suitable for the flat plate, but also is suitable for a rib-adding flat plate. Furthermore, the test debugging of the single axial compression load and the single shearing load under the condition that the rib-adding flat plate is invariable in an installing posture can be realized, so that the reference can be provided for the analysis of the stress state of a lower wall plate under the joint action of the compression load and the shearing load. The device applies shearing force by the self-balance principle of a whole frame and a 'load balancer', so that the shearing force can be evenly applied, the axial rigidity of the rib-adding flat plate can not be enhanced due to an adopted segmental shearing reinforcement block, a compression load applying effect can not be influenced, and a 'side frame effect' can be avoided.

A rotatable circular crossection cervical pillow is manually rotated in a continuous fashion as desired by a person whenever a fresh clean contact spot is sought, or a contact spot of variable support is sought, while the pillow is still attached to a seat back. The rotatable pillow is a cylinder of medium and/or firm high density polyurethane foam. An axial through-hole in the center permits the snug insertion of a rigid length of tubing to give the pillow axial rigidity. Swivel fixtures are attached at each end of the pillow by virtue of the central tube. A fabric cover with an opening closure covers the entire polyurethane cylinder snugly. Optionally the cover may carry therapeutic imparting elements therein. Straps with adjustable buckles are attached to each swivel fixture. Therefore, the cervical pillow rotates easily while still strap-attached to the seat back.

The invention provides a closed fluid static pressure/ dynamic static pressure revolving worktable with high precision and rigidity, and relates to the field of automatic equipment of precision machinery. A plurality of axial bearings and radial bearings arranged along the axial direction are fixed by a plurality of slewing rings and bearing guide rails; the revolving worktable is provided with a balanced bearing to balance; kinematic pairs of a plurality of bearings rotate synchronously and are connected; fixed pairs of the bearings are connected through a base of the worktable; and sliding pairs of the radial bearings and bearing pairs of the axial bearings move rigidly, integrally and synchronously; and a relatively still sliding surface of the sliding pair of each bearing is provided with an oil chamber. Under the conditions that fluid pressure of the revolving worktable is same and the volume is equal, the axial rigidity, the radial rigidity and the bearing capacity are multiply improved, and the improved multiple is in direct proportion to the number of the bearings. The revolving worktable has the advantages of convenient design, simple manufacture, low cost, high precision and no abrasion. The revolving worktable is a key part of a high-precision metal working machinery, in particular to a functional part of large and oversize heavy equipment by using the key technology, and has more remarkable advantages in manufacturing equipment in the fields of navigation, astronavigation, large aircraft, and the like.

The invention discloses a three-freedom-degree precision locating platform which comprises a base and a moving platform arranged in the base. The base and the moving platform are connected through three hinge expansion mechanisms evenly distributed in the peripheral direction of the platform and three plate-shaped flexible hinge mechanisms. One end of each hinge expansion mechanism is in flexible connection with the base, the other end of the hinge expansion mechanism is in flexible connection with the moving platform, the middle of the hinge expansion mechanism is provided with the input end, and the input end is connected with a piezoelectric ceramic driver. Each plate-shaped flexible hinge mechanism comprises an arc flexible plate and one to five radial flexible plates perpendicularly fixed to the arc flexible plate. The three-freedom-degree precision locating platform can achieve two horizontal movements and one rotation and is simple and compact in structure. Displacement expansion and force transmission are conducted by utilizing the hinge expansion mechanisms, so that the plate-shaped flexible hinge mechanisms have elastic deformation to drive the moving platform to move and achieve output of micro-nano displacement, the output displacement is large, and axial rigidity is high. The three-freedom-degree precision locating platform can serve as an auxiliary locating platform of a nano-micro operating system to achieve micro-feeding and precise locating.

The invention belongs to the technical field of mechanical measurement and is applicable to measurement of radial stiffness and axial stiffness of bearings. The measurement principle is based on a relationship between the bearing stiffness and inherent vibration frequency of a shaft for test. The method comprises the following steps of: in the process of measuring the radial stiffness of the bearing, solving a function relationship between the radial stiffness of the bearing and the first-order transverse vibration frequency of a shaft for test, building a physical system among the shaft for test, a measured bearing and a rigid support, measuring the first-order radial vibration inherent frequency of the shaft for test, and finally, calculating the radial stiffness of the bearing according to a function relationship between the inherent vibration frequency and the radial stiffness of the bearing; and in the process of measuring the axial stiffness of the bearing, solving the mass of the shaft for test, building a physical system among the shaft for test, the measured bearing and the rigid support, measuring the first-order axial vibration inherent frequency of the shaft for test, and finally, calculating the axial stiffness of the bearing according to a relationship between the vibration inherent frequency and the axial stiffness of the bearing.

The invention discloses a motorized spindle device supported by high-speed hybrid bearings and lubricated by two phases of gas and liquid. The motorized spindle device comprises a shell, a cooling water jacket, a motorized spindle, a motor stator, a motor rotor, a front bearing, a rear bearing and a gas thrust bearing, wherein the cooling water jacket is fixed on the inner side of the shell, and the front and rear bearings support the two ends of the motorized spindle. Both of the front and rear bearings supporting the motorized spindle are hybrid sliding bearings and can promote the rigidity and the stability of the spindle and reduce temperature rise. Front and rear annular water return grooves are respectively formed in the two ends of each bearing, and lubricating medium liquid flows into the annular water return grooves and then flows out of the shell through a shell water outlet channel. Two gas seal devices are respectively arranged on two sides of each hybrid bearing and can prevent the lubricating medium liquid from flowing into the clearance between the motor stator and the motor rotor and flowing out of the shell along the axial direction of the motorized spindle. According to the gas thrust bearing, gas is used as the lubricating medium of the thrust bearing, and the gas thrust bearing provides the motorized spindle with axial rigidity and controls the axial displacement and the stability of the motorized spindle.

The invention relates to a device for automatically eliminating clearances of a screw drive pair, which comprises a leading screw, a main nut, a bolt, a machine tool sliding plate, an adjusting bolt, a spring, a guide post, a nut with an inclined plane, a bolt, a locking nut, a wedge block and a ball. The device is characterized in that the main nut and the nut with the inclined plane are connected with the leading screw respectively, the main nut is connected with the machine tool sliding plate through the bolt, and the flange of the nut with the inclined plane is provided with a through hole so that the nut with the inclined plane can move axially along the guide post. The wedge block with a self-locking function is supported between the main nut and the nut with the inclined plane; andone end of the spring is pressed on the wedge block with the self-locking function, while the other end is tightly pressed by the adjusting bolt. The incline plane of the nut with the inclined plane is provided with a guide groove. The device automatically eliminates axial clearances, has no reverse idle stroke, has adjustable pretightening force, good axial rigidity, smooth transmission, low cost, compact structure and high space utilization rate, is applied to feed drive systems of a metal cutting machine tool and a numerical control machine tool, and can greatly improve the processing accuracy.

The invention provides a rhombus oblique-wedge quadratured drive type piezoelectric stick-slip linear motor and a composite excitation method thereof to solve the problem that in an existing piezoelectric stick-slip linear motor, the mechanical output property is limited due to the fact that comprehensive regulation on friction force is difficult. The rhombus oblique-wedge quadratured drive type piezoelectric stick-slip linear motor is composed of an oblique-wedge stator, a preloading device, a mounting support and a rotor; the oblique-wedge stator adopts asymmetrical hinges of a wedged structure, lateral displacement is generated through an oblique-wedge rhombus motion converter and the ununiform axial rigidity distribution characteristic of a stator drive foot, the friction drive force is increased, and the friction resistance is decreased; meanwhile, friction regulation waves are overlapped into sawtooth drive waves in the rapid deformation stage of the stator, comprehensive regulation on the friction force is achieved, and the mechanical output characteristic of the piezoelectric stick-slip linear motor is significantly promoted. The rhombus oblique-wedge quadratured drive type piezoelectric stick-slip linear motor has the advantages of being simple in structure, high in precision, large in stroke and the like and has the good application prospect in the fields of micro-nano precise driving and positioning such as machining of precise medical instruments, optical precise instruments and semiconductors.

A passive magnetic bearing which has an exceptionally low friction couple. Radial and axial restraint is achieved through magnetic and mechanical means. The embodiment of the passive magnetic bearing has two axially magnetized rings, which each exhibit at least one pair of north and south poles. The magnetized rings are positioned in a manner where the poles are in a repulsive magnetic interaction such that the plane of symmetry which separates the like poles lies perpendicular to the axis of the rotation of a shaft and this radially constrains the movement of the shaft. Axial rigidity is added to the system by the use of ceramic bearings and related axial retaining mechanisms on one of the ring magnets thus maintaining the magnetic bearing in an otherwise unstable axial plane.

The invention discloses a twin-web rotor disc provided with disc cavity flow-guide rib plates. The plurality of flow-guide rib plates are arranged on two spoke plates of the twin-web rotor disc. Disc edge cool air channels are evenly distributed in the radial direction in the edge of the rotor disc along the circumference and cooling air enters cooling blades through the disc edge cool air channels from disc cavity of the twin-web rotor disc. An annular tongue plate is embedded between a front hub and a rear hub of the twin-web rotor disc, and a central channel of the tongue plate is communicated with an inner cavity of the rotor disc. The flow guide rib plates are distributed in a streamline layered mode in the rotating direction of the rotor disc and realizes a centrifugal supercharging effect when the rotor disc is rotating, so that flow speed and the pressure of the cooling air in the disc cavity are increased. The heat exchange area is increased, the convective heat exchange efficiency of the disc cavity is improved by using the flow guide rib plates, and the effect of enhancing heat exchange is achieved. The tongue plate structure is added between the front hub and the rear hub of the rotor disc, and the axial rigidity of an opening in the disc center is improved. By utilizing variable cross-section channels in the tongue plate and the disc edge, the pressure and the flow speed of the cooling air passing through the channels can be controlled.

The invention discloses a method for stimulating a fluid-solid-heat coupling value of a machine tool spindle, which comprises the steps of: establishing a model of a spindle cooling liquid, replacing bearings in a spindle with equivalent rings with same sizes, simplifying the model; calculating relevant external boundary conditions of a spindle temperature field; guiding into grid division software ANSYS, ICEM and CFD for carrying out fluid and solid grid division; guiding into CFX software for carrying out fluid-solid-heat coupling calculation; guiding the simplified geometrical model into a stable temperature field module in a workbench, neglecting a cooling liquid model, re-dividing a grid; re-calculating a temperature field of the spindle according to the temperature field boundary condition; calculating radial and axial elastic modulus of the equivalent ring by using radial and axial rigidity of each bearing, and correcting the elastic modulus of each equivalent ring in the workbench; guiding the temperature obtained from the calculation of the stable temperature field into a stable static analyzing module in the workbench, and calculating the heat deformation.

A flexible joint has an extension mounted to a housing for relative angular displacement. Two or more annular elastomeric flex elements are stacked in a co-axial fashion and joined mechanically to mount the extension to the housing so that the flex elements react in parallel to angular and axial displacements of the extension with respect to the housing so that tensile load upon the extension places each of the flex elements in compression to split and share the tensile load among the flex elements in proportion to their relative axial stiffnesses. Therefore, for a given housing size or footprint, the overall load capacity is increased, and the lifetime of the flexible joint is increased for a given load capacity. The flex elements may have a common center of rotation, and the flex elements may be disposed either on the same side of the center of rotation or on opposite sides.

The invention provides a non-shaft high-precision static pressure numerical control rotary worktable. The rotary worktable adopts a hollow non-shaft structure; the surface of the worktable and a motor rotor are directly arranged on a bearing rotor of a liquid static pressure bearing respectively; and the rotary worktable adopts a realizing mode of direct-drive motor driving, rotary encoder feedback and computer numerical control, so that the rotary worktable lowers the difficulty of processing, assembling and adjusting parts of the rotary worktable, improves the precision of the rotary worktable and has the characteristics of compact structure, small inertia and high dynamic property and rigidity. The designed positioning precision of the rotary worktable is 3.5 angular seconds, the repeated positioning precision of the rotary worktable is 1 angular second, the resolution is 0.5 angular second, the radial rigidity is 4,000N/mu m, and the axial rigidity is 30,000N/mu m.