121 results about "Involute" patented technology

The invention discloses a straight gear shape-free measurement method based on single-group line structured light. The method comprises the following steps: constructing an optical platform coordinate system, carrying out line structured light coordinate system calibration through a spherical calibration body, and calibrating the rotation center of a precision turntable; installing a measured straight gear, establishing a straight gear coordinate system, and adjusting the position of the linear structure optical measuring head, so that the measuring field of view of the linear structure optical measuring head covers a root circle to an addendum circle of the straight gear; the straight gear is installed on a precision rotary table, the straight gear is driven to rotate at a constant speed, a linear structure optical probe scans and collects straight gear contour point cloud data and circular grating angle information, and tooth surface three-dimensional point cloud data is obtained; based on the three-dimensional point cloud data of the tooth surface, extracting an addendum circle, a dedendum circle and an involute tooth profile, and calculating spur gear parameters; performing reverse three-dimensional shape modification tooth surface identification on the shape modification straight gear to generate a three-dimensional deviation diagram; and outputting a measurement result and printing a report. The problems of shape-free rapid measurement, modification tooth surface identification and tooth surface three-dimensional deviation characterization of the straight gear with unknown basic parameters are solved.

A value traceability method for an involute curve with a large base circle radius. The method comprises the following steps: step 1, determining a coordinate system for value traceability and value transfer parameters; step 2, adjusting the pose of an involute template (8); step 3, adjusting the position of the involute template (8); step 4, calibrating involute parameters; and step 5, eliminating coordinate system establishment errors to achieve calibration of a measurement instrument. The method fills the gap of value traceability methods for large-size gears with diameters greater than 500 mm, and can effectively identify the impact of coordinate system establishment errors on the accuracy of tooth profile measurement, and improve the applicability of a large-gear measurement instrument (9) in complex environments such as on-machine measurement. The method enables high-precision involute measurement, is simple and easy to implement, offers high measurement accuracy, facilitates transportation and installation adjustments, and has good market application prospects and promotion value.

The static pressure knife rest of the gear shaping machine comprises an eccentric disc, a swing rod is hinged to the eccentric disc, and the other end of the swing rod is hinged to the top end of a knife shaft through a ball pull rod and a ball head. The cutter shaft penetrates through the cutter rest body; a cutter is mounted at the lower end of the cutter shaft; a worm gear and a worm are installed at the upper end of the tool rest body, and the worm gear is pressed through a large flange plate to be axially fixed. The cutter shaft penetrates through the worm gear and an inner hole of the cutter shaft sleeve at the same time. Due to the fact that the outer circle profile face of the four-tooth tooth-shaped tooth crest of the formed hydrostatic guide rail is wide, enough space can be provided for designing a radial four-cavity centripetal hydrostatic bearing, and therefore the upper end of a cutter shaft not only has centripetal clamping static pressure formed by static pressure cavities of involute tooth faces of the hydrostatic spline guide rail but also has static pressure clamping force of the tooth crest. The rigidity of the upper end of the cutter shaft is enhanced through superposition of the two clamping forces.

The invention discloses an involute helical gear forming grinding force prediction method, which comprises the following steps: firstly, based on a helical gear forming grinding space motion relationship, establishing a helical tooth surface model comprising an involute surface and a tooth root transition curved surface, and constructing a geometric contact model of a grinding wheel and a gear; then, tooth surface deformation data obtained after heat treatment are obtained through a three-coordinate measuring machine, coordinate mapping is carried out, and the grinding depth and contact parameters are corrected; on the basis, a grinding force integral model considering the heat treatment influence is established by combining a plane grinding mechanism, and integral calculation is carried out on tangential and normal grinding force of a tooth surface involute section, a transition arc section and a tooth bottom section; finally, actual measurement data are obtained through a grinding experiment, and model parameter calibration is completed. According to the method, dynamic and accurate prediction of tangential and normal grinding force in the bevel gear forming and grinding process can be achieved, and a reliable basis is provided for mechanical behavior analysis and process optimization in the gear machining process.

The invention relates to the technical field of high-precision grinding machining of screw elements of large extrusion granulation units, in particular to a rapid alignment and positioning device for an involute spline screw element. The problem of relative position deviation of the machined internal spline and the outer contour milling shape caused by a fit clearance in the original machining process is solved, the high-precision machining effect is achieved, the machining precision of the screw element is ensured, and the clamping and positioning errors in the screw element assembling process are reduced.

According to the involute type multi-arm spiral sound array and the method, in the array, a center supporting piece is of a regular heptagonal plate-shaped structure, seven side edges of the center supporting piece are connected with seven base circle spiral arm connecting pieces in a welding mode respectively, the other end of each base circle spiral arm connecting piece is connected with an internal spiral arm structure, and the other end of each internal spiral arm structure is connected with an outer spiral arm structure; the other end of each internal spiral arm structure is connected with one middle spiral arm structure, and the other end of each middle spiral arm structure is connected with one external spiral arm structure; each external spiral arm structure is in welded connection with the middle spiral arm structure adjacent in the anticlockwise direction through an adjacent arm supporting rod; the bottom face of the center supporting piece is connected with the array connecting piece in a welded mode, and the array connecting piece is connected with the array supporting base structure in a fastened mode through bolts. The internal spiral arm structure, the middle spiral arm structure and the external spiral arm structure are provided with circular through holes used for installing microphones, and the circle centers of the through holes are located on an involute generated by the same base circle.

The present invention relates to a push chain device, comprising: a push chain (10) including a curved portion (10b) and a straight portion (10a) along an axis, the chain including links (12) hinged to the axis; a push chain guide (20); a drive sprocket (1) having teeth (2) interlocked with the push chain, the sprocket contacting the push chain through a circular involute-shaped contact surface (2a), the contact surface (2a) being a tooth, the teeth (2) engaging with the chain, and defining a line of action at an angle between -10° and 10° to the axis of the straight portion, the line of action being offset relative to the hinge axis of the link, the sprocket contacting the straight portion (10a) but not the curved portion (10b), and being mounted such that it can rotate on an axis located on the side of the chain opposite to the center of curvature of the curved portion (10b), the contact surface (2a) including a convex front surface toward the straight portion (10a) and a rear surface toward the curved portion (10b) when the teeth (2) interlock.

The utility model relates to a stationary shaft shoulder stirring head which comprises a shaft shoulder and a stirring head coaxially butted with the tail end of the shaft shoulder, the stirring head is of a circular truncated cone structure, the flaring end of the stirring head is coaxially butted with the tail end of the shaft shoulder, and a threaded groove is formed in the annular wall in the axial direction of the stirring head; the stirring head of the circular truncated cone structure is adopted, the design of the axial thread grooves in the annular wall can play a spiral flow guide role on softened metal materials, the problem of material overflow caused by a traditional plane shaft shoulder is effectively avoided, the welding seam filling rate and the joint compactness are remarkably improved, and defects are reduced. Through the synergistic effect of the circular truncated cone structure and the threaded groove, stress is dispersed through the continuous and smooth geometrical shape, the problem of stress concentration caused by multi-groove spaced arrangement of involute grooves in the prior art is solved, meanwhile, the design that the flaring end of the stirring head is embedded into the shaft shoulder ring groove enhances the connection stability, vibration abrasion under high-speed rotation is reduced, and the stirring effect is improved. Durability of the stirring head is remarkably improved, and use cost is reduced.

The invention discloses a wear-resistant elastoplastic body quincunx pump molded line and a quincunx pump thereof. The molded line is fixed by an outer rotor, and an inner rotor performs eccentric motion along the inner side of the outer rotor and is formed by conjugate meshing; the molded line of a first worm claw part of the outer rotor consists of an arc section AB, an arc section BC, a transition cubic curve section CD, an involute section DE, a transition cubic curve section EF and an arc section FG; the molded line of the second worm claw part of the inner rotor is composed of an arc section ab, an arc section bc, a transition cubic curve section cd, an involute section de, a transition cubic curve section ef and an arc section fg. The characteristics of accurate conjugate meshing and point contact of the involute are adopted, compared with line contact of other molded lines, friction abrasion between rotors is reduced, the sealing effect between the involute and the inner wall of a pump body is good under the high-pressure conveying working condition, it is guaranteed that the conveying pressure is lasting and stable, pulsation is reduced, and the working efficiency is improved.

The invention discloses an involute cylindrical gear heat treatment spiral line deviation calculation method and system, electronic equipment and a storage medium. The method comprises the steps that a pre-heat tooth surface point set and a post-heat tooth surface point set are obtained; dividing the pre-heating tooth surface point set into m first sub-point sets, and dividing the post-heating tooth surface point set into m second sub-point sets; constructing a cylindrical surface of the reference circle, and solving a first intersection point set of each first sub-point set and the cylindrical surface and a second intersection point set of each second sub-point set and the cylindrical surface; solving a distance difference value between two points of the first intersection point set and the second intersection point set; solving a distance difference value of each point of the first intersection point set relative to the initial point; a spiral line deformation difference value curve is constructed, data selection is conducted on the spiral line deformation difference value curve again according to the value counting range of the spiral line, and a final spiral line deformation curve is obtained; and according to the final spiral line deformation curve, a spiral line deviation value is solved. According to the invention, the helix deviation can be accurately calculated.

An online measurement gear precision evaluation method considering geometric errors of a large-specification gear making machine tool is characterized in that a measurement path is planned based on the large-specification machine tool which is provided with an online measurement system and contains X, Y, Z and C axes, an online measurement system geometric error model is established, the influence of the geometric errors on a measurement result is analyzed, and the precision of the large-specification gear making machine tool is evaluated. And obtaining a theoretical comparison position corresponding to the actual measurement point, and evaluating the processed measurement result. A measurement path is planned according to an involute helical gear measurement principle and shaft configuration characteristics of a large-specification gear making machine tool; establishing a geometric error model in combination with the measurement path; and analyzing the influence of the geometric error on the measurement result, correcting the measurement result, and evaluating the corrected measurement result. According to the invention, the online measurement evaluation accuracy of the large-specification gear making machine tool is improved.

The application discloses a high-speed high-load low-vibration multi-engagement-zone gear and a tooth profile design method thereof, wherein the high-speed high-load low-vibration multi-engagement-zone gear comprises a first gear and a second gear, a tooth profile curve of the first gear comprises a first tooth crest curve segment L3, a first involute curve segment L2 and a first tooth root curve segment L1, a tooth profile curve of the second gear comprises a second tooth crest curve segment L3', a second involute curve segment L2' and a second tooth root curve segment L1', and the first tooth crest curve segment L3 and the second tooth root curve segment L1' are continuously engaged, the first involute curve segment L2 and the second involute curve segment L2' are continuously engaged, and the first tooth root curve segment L1 and the second tooth crest curve segment L3' are continuously engaged during the engagement of the first gear and the second gear. The application can effectively bear higher load, improves the load bearing capacity and the end face coincidence degree of the gear pair, and can make the transmission process more stable and better adapt to high-speed working conditions.

The utility model discloses a variable diameter variable pitch screw rotor, including intermeshing left rotors and right rotors, the end face profile of left rotors with right rotors is same, all by 7 curves first and last connected closed, wherein 7 curves include involute section AB, circular arc section BC, dedendum circular arc section CD, circular arc section DE, cycloid equidistant curve section EF, dedendum circular arc section FG and circular arc conjugate curve section GA, the circular arc BC of left rotors is intermeshed with the circular arc conjugate curve A'G' of right rotors, and the rest line sections are sequentially intermeshed according to the rotating direction of left rotors and right rotors respectively, the screw pitch of left rotors and right rotors is segmented along the axial direction, the left rotors are conical along the air inlet end to the air outlet end, and the right rotors are conical along the air inlet end to the air outlet end. The utility model further provides a vacuum pump. The device provided by the utility model can effectively improve the internal compression ratio and efficiency of the vacuum pump.

The utility model discloses a three -section type conical screw rotor, three -section type conical screw rotor is divided into suction section, compression section and exhaust section in proper order along screw axial direction, the suction section is equal cross section and equal pitch along screw axial direction, the compression section adopts and is variable cross section and variable pitch along screw axial direction, the exhaust section is equal cross section and equal pitch along screw axial direction, the cross section width of suction section along screw axial direction is greater than the cross section width of exhaust section along screw axial direction, the end face profile equation of each section is same, and all are by five curves of abutting together closed, and the five curves include involute section AB, addendum circle arc section BC, long amplitude outside cycloid section CD, dedendum circle arc section DE and point conjugate curve section EA. The utility model also provides a vacuum pump. The device of the utility model can effectively reduce the noise of vacuum pump, reduce the clearance backflow, thereby improve its reliable stability and practical life.

The machining method comprises the following steps that a disc type tooth-shaped milling cutter is adopted to be fixed to a machine tool spindle, and a gear blank is installed on a device capable of dividing teeth and rotating at a certain angle; the disc-type tooth-shaped milling cutter does linear motion and rotary motion at the same time, the linear motion speed of the disc-type tooth-shaped milling cutter is set to v1, the angular speed at the gear milling pitch circle of the gear blank is converted into the linear speed, namely, the pitch circle linear speed of the gear blank is v2, and the v1 and the v2 are the same in direction and equal in speed; and the arc involute tooth-shaped structure with the symmetrical middle position is obtained. The middle-position arc cylindrical gear can replace herringbone teeth, is good in manufacturability and low in manufacturing cost, can be transformed through numerical control milling equipment, is more stable and lower in noise compared with a cylindrical gear, and meanwhile, the number of meshed teeth is larger.

The present invention relates to a spiral for a spiral compressor and a spiral compressor with such a spiral. The spiral compressor (100) has a first spiral (10) and a second spiral (20), wherein the second spiral (20) and the first spiral (10) interact to form compressor chambers for compressing a medium. The first spiral (10) is a stationary spiral, and the second spiral (20) is an orbiting spiral. The first spiral (10) and the second spiral (20) each have an end plate (29) and a spiral turn (21).At least the outer surfaces (222) or the inner surfaces (221) of the spiral screw (21) of at least one of the first spiral (10) or the second spiral (20) use an involute as a reference for generating at least the outer surfaces (222) or the inner surfaces (221), wherein the distance between the at least one outer surface (222) or inner surface (221) of the spiral (21) and the involute gradually increases from a predetermined point between the start point and the end point of the involute to the end point of the involute along the generation line of the involute. The spiral and the spiral compressor improve the sealing effect between the turns of the spiral.

The utility model belongs to the technical field of mineral separation, and discloses a rotor suitable for a flotation machine. The rotor comprises a central shaft, a fixed disc and a plurality of blades; the fixed disc is fixedly arranged on the central shaft in a sleeving manner; the blades are arranged in the circumferential direction of the center shaft at intervals, the first side face of any blade is fixedly attached to the outer circumferential wall of the center shaft, and the second side face of any blade is fixedly attached to the lower side wall of the fixing disc. Wherein the first side face is defined as the side face, close to the center shaft, of any blade, and the second side face is defined as the side face, close to the fixing disc, of any blade; the lower side wall of the fixed disc is of an arc-shaped structure protruding towards the direction of each blade; a plurality of notches are formed in the sides, away from the center shaft, of the blades in the axial direction of the center shaft, and the opposite faces of the first side faces of the blades form an involute structure. According to the utility model, the wear rate of the rotor can be reduced, and the mineral separation efficiency can be effectively improved.

The spiral energy storage spring and the compression spring are integrated inside, or the spiral energy storage spring, the magnetic spring and the planar spring are integrated inside, so as to realize energy storage and passive flexibility, reduce driving consumption and meet the requirement of driving agility.SOLUTION: Disclosed is a flexible joint based on an elastic element, including an involute small-tooth-number difference reducer, a spiral energy storage spring, and a flexible output module / composite flexible output module. The involute small-number-of-teeth difference reduction gear employs only an eccentric input shaft, a pair of involute internal tooth rings, and an involute planetary gear to achieve oscillation and rotation motions of the involute planetary gear. The power output of the output disc is transmitted by the interaction of the column pin and the first column pin working hole of the involute planetary gear or the second column pin working hole of the output disc. The accuracy requirement can be easily met only by the meshing form of the pair of gears, the axial dimension is compact, the pair of gears adopt involute tooth profile, and the manufacturing cost is low.SELECTED DRAWING: Figure 1

A stator twisting apparatus and method for an axial flux hairpin motor. The apparatus comprises an upper drive disc (1), an upper mold tooth assembly (2), a central guide disc (3), a lower mold tooth assembly (4), a lower drive disc (5), and a twisting power assembly, wherein the upper mold tooth assembly (2) comprises a plurality of upper mold teeth (21), the upper mold teeth (21) being mounted on the upper surface of the central guide disc (3); the lower mold tooth assembly (4) comprises a plurality of lower mold teeth (41), the lower mold teeth (41) being mounted on the lower surface of the central guide disc (3); the upper drive disc (1) is provided with a plurality of first involute slide rails (8); the upper drive disc (1) is mounted on the upper surface of the central guide disc (3), and at least part of the upper mold teeth (21) pass through the first involute slide rails (8); the lower drive disc (5) is provided with a plurality of second involute slide rails (18); the lower drive disc (5) is mounted on the lower surface of the central guide disc (3), and at least part of the lower mold teeth (41) pass through the second involute slide rails (18).

The invention discloses a thin plate end pre-curling method and device based on involute curvature, and the method comprises the steps: building an involute curvature model, and designing an up-down opposite-pressing type extrusion device composed of a plurality of extrusion modules with curvatures arranged along an involute in a segmented manner based on the involute curvature model; positioning the end part of the thin plate at a position corresponding to the target curvature in the extrusion device; the extrusion device is driven to be closed, so that the end of the thin plate is subjected to continuous plastic bending along an involute track; the pre-curling curvature is compensated according to the springback characteristic of the thin plate material; and the pre-curled thin plate is fed into a plate rolling machine to be integrally rolled, and the curvature of the ends is continuous and consistent with the curvature of the cylinder body. By means of the characteristic that the curvature of the involute continuously changes from small to large, elastic springback in the pre-bending process of the end of the high-springback material can be effectively reduced, straight edges of the end after edge rolling are remarkably reduced, and the overall roundness of the cylinder and the welding assembly quality are improved.

The invention relates to the technical field of gear machining, and discloses line contact generating gear grinding equipment for an involute cylindrical gear, a grinding wheel and a machining method.The equipment comprises a lathe bed and a workpiece unit arranged on the lathe bed, and the workpiece unit comprises a workpiece rotating mechanism and a clamping mechanism connected with the workpiece rotating mechanism; a workpiece to be machined is clamped in the clamping mechanism, and a first grinding wheel unit and a second grinding wheel unit are arranged on the lathe bed. The first grinding wheel unit comprises a first x-axis sliding table connected to the lathe bed in a sliding mode, a first y-axis sliding table is arranged on the first x-axis sliding table, and a first z-axis sliding table is arranged on the first y-axis sliding table. Instantaneous linear contact is formed between the tooth surface of the grinding wheel and the tooth surface of the workpiece to be machined, the tooth surface machining integrity is improved, the higher axial feeding speed can be adopted, the grinding efficiency is improved, and synchronous optimization of the machining efficiency and the machining quality is achieved.

The present disclosure proposes a scroll compressor, comprising: a housing (100); the two scrolls (200 and 300) are contained in the shell (100), the scroll bodies of the two scrolls (200 and 300) extend along involutes respectively and are meshed with each other, and the scroll body of at least one scroll is provided with a sealing groove (340) recessed from the top face of the scroll body. The sealing groove (340) extends from an inner end wall (341) close to the circle center of the involute base circle to an outer end wall (342) far away from the circle center of the involute base circle along the involute, and is provided with a sealing strip (350) and a pre-tightening spring (360); the pre-tightening spring (360) is wave-shaped and has a plurality of wave crest portions (363) abutting against the bottom (351) of the sealing strip (350) and a plurality of wave trough portions (364) abutting against the bottom wall (344) of the sealing groove (340), and the spring stiffness of the pre-tightening spring (360) decreases in the direction from the inner end wall (341) to the outer end wall (342).

A method for measuring wear of an involute spline in a hub drive is provided. The method includes a step of application of a mechanical brake to fix the sun gear in position, a step of application of an alternating torque on the rotor, a step of measuring an angular displacement of the rotor versus the stator, and a step of translating the measured angular displacement of the rotor into a wear value of the involute spline.

The invention discloses a special tooth root digging and gear shaping method. The method comprises the following steps of firstly calculating involute meshing starting circles dnf1 and dnf2 of two gears by utilizing the tooth number Z, modulus m, pressure angle alpha and mounting center distance a of paired meshing gears; calculating the tooth space width K at the starting circle dnf of the gear according to a standard calculation formula; and after the value of K is determined, a single tooth root shaping method is adopted, the width of the slotting tool is equal to the tooth groove width K, the slotting tool is aligned with the tooth groove center of the standard reserved grinding gear to shape the tooth root, and the tool can be stopped when the tooth root circle diameter df is equal to (Z-2. 5) m. A special tooth root digging gear shaping method is adopted to replace a special reserved grinding root digging hob, and the problems that the special reserved grinding root digging hob is narrow in adaptability, high in price and high in cost are solved.

The invention belongs to the technical field of gear transmission systems, and particularly discloses a gear meshing optimization method and system based on random progressive iteration and regularization, and the method comprises the following steps: carrying out the data sampling and preliminary fitting based on a gear tooth surface curve model; aiming at the preliminary fitting, setting an adaptive double-layer optimization framework which comprises a first layer of control point updating strategy optimization and a second layer of parameter distribution optimization, constructing an objective function, and realizing adaptive fusion optimization in the same iterative loop to obtain an optimized involute curve and a curved surface; and for the meshing region, introducing second-order difference smoothing, carrying out multi-objective optimization, and outputting a finally fitted NURBS control point P and an optimized parameter mapping weight w. By adopting the technical scheme, on the basis of least square approximation (LSPIA), the adaptive double-layer optimization technology is integrated, and the fitting precision, the fairness and the convergence speed are remarkably improved by jointly optimizing a control point updating strategy and parameter distribution.

The application discloses a grinding machining method for involute cylindrical gear parabolic modification, selects multiple position points on the parabolic modification tooth profile, fits into an approximate circular arc, calculates the circular arc drum-shaped amount and the fitting circular arc error value, and solves the forming grinding machine tool machining problem of the involute cylindrical gear parabolic modification. The application has the advantages of simple operation.

The invention discloses an animal food forming machine, which belongs to the technical field of forming machines and comprises a main roller, a slave roller, a conveying part, a secondary roller and a stirring part which are arranged on a base. Wherein a plurality of forming spaces are formed in the main roller, pushing elements extending into the main roller are arranged in the forming spaces, an extrusion part is arranged in the main roller and provided with an involute curved surface, a first gap is formed between the involute curved surface and the inner side wall of the main roller, and the pushing elements are extruded by the involute curved surface when entering the first gap; therefore, the residual materials in the forming space are ejected out. The device has the advantages that the main roller rotates to enable the different pushing elements to enter the first gap in sequence, and the pushing elements make contact with the involute curved surface of the first gap, so that the pushing elements are pushed step by step. And finally, the secondary roller is pushed to reset again. Therefore, the problem that excess materials are easy to remain in the groove of the forming machine in the prior art is solved.

This invention discloses a design system for machining the backlash angle of a spline broach based on an involute curve. The system includes a broach original tooth profile parameter input module for inputting basic parameters of the broach spline tooth profile; a new involute parameter calculation module for calculating and outputting new involute parameters of the broach spline teeth based on the basic parameters of the broach spline tooth profile; a gauge bar parameter calculation module for calculating and outputting gauge bar parameters based on the new involute parameters of the broach spline teeth; and a broach tooth profile parameter update output module for outputting tooth profile parameters related to the new involute curve used for the backlash angle of the broach spline teeth from the basic parameters of the broach spline tooth profile, the new involute parameters of the broach spline teeth, and the gauge bar parameters. The new involute curve obtained through this design system allows for direct machining of the backlash angle of the broach spline teeth. This backlash angle machining can be achieved without changing the fixture, while ensuring machining accuracy.

The method comprises: - a step of applying a mechanical brake to fix the sun gear (20) in position, - a step of applying an alternating torque to the rotor (16), - a step of measuring an angular displacement of the rotor (16) with respect to the stator (14), and - a step of converting the measured angular displacement of the rotor (16) into a value of involute spline wear.

The spiral energy storage spring and the compression spring are integrated inside, or the spiral energy storage spring, the magnetic spring and the plane spring are integrated inside, so as to realize energy storage and passive flexibility, reduce the driving consumption and meet the requirements of driving agility. [Solution] A flexible joint based on an elastic element is disclosed, including an involute small tooth difference reducer, a spiral energy storage spring, and a flexible output module / composite flexible output module. The involute small tooth difference reducer uses only an eccentric input shaft, a pair of involute internal tooth rings, and involute planetary gears to realize involute planetary gear oscillation and rotation. The power output of the output platen is transmitted through the interaction of the column pin and the first column pin operating hole of the involute planetary gear or the second column pin operating hole of the output platen. The precision requirements can be easily met by simply using a pair of gears meshing, the axial dimension is compact, and the pair of gears use an involute tooth profile, so manufacturing costs are low.