100 results about "Recirculating ball" patented technology

The invention discloses a recirculating ball type electric power steering system fault self-checking method and system and a readable medium, and relates to the technical field of vehicles, and the method comprises the steps: storing a signal transmission path and each function node, determining the type of an influence factor which influences the instruction execution accuracy of the function node, and determining the instruction execution accuracy of the function node; analyzing and acquiring the relationship between the fluctuation amplitude of the data signal at each function node and the numerical value of the influence factor, storing the relationship as a correction model, and storing a first relationship model for reflecting the data association relationship among the function nodes on the same signal transmission path; acquiring real-time data and source data of various impact factors, and generating theoretical response data according to the first relation model, the real-time impact factor data and the correction model; the actual response data is collected, the deviation amplitude between the actual response data and the theoretical response data is calculated, whether the function node breaks down or has a potential fault is judged according to the deviation amplitude, early warning is output, and the fault detection accuracy and the potential fault pre-judgment capability are greatly improved through the technical scheme.

An actuation device for a brake disc has a recirculating ball screw-nut screw assembly and a thrust bearing. The recirculating ball screw-nut screw assembly has a threaded shaft and a nut screw screwed onto the threaded shaft. The threaded shaft and the nut screw extend in direction of an actuation axis. The threaded shaft extends between a front end and a rear end of the threaded shaft. The nut screw receives a torque generatable by a gearmotor. A rotation of the nut screw with respect to the threaded shaft results in a translation of the threaded shaft with respect to the nut screw in the direction of the actuation axis. The thrust bearing provides a reaction rest for the nut screw in the direction of the actuation axis. The thrust bearing is positioned within an extension of the threaded shaft between the front and rear ends of the threaded shaft.

The utility model belongs to the technical field of gear and rack assembly, and particularly relates to a gear and rack assembly structure for a recirculating ball type steering gear, which comprises a mounting seat and a support frame mounted on the mounting seat, a shaft rotating rod is mounted on the support frame in a threaded manner, and the periphery of the shaft rotating rod is rotatably connected with a mounting wheel through a bearing. A dismounting mechanism is connected between the mounting seat and the support frame; the dismounting and mounting mechanism comprises a limiting insertion hole formed in the inner side wall of the supporting frame and a fixing block fixedly connected to the surface of the upper end of the mounting base, and a sliding groove is formed in the surface of the upper end of the fixing block. By means of the design, the disassembly and assembly process is simplified, and operation convenience is improved. When parts need to be maintained or replaced, a user can easily detach the supporting frame from the installation base, the supporting frame is rapidly installed back after maintenance is completed, the maintenance time is greatly shortened, and the maintenance efficiency is improved.

The invention relates to a gas injector for an internal combustion engine, comprising a housing (1) and an injector valve needle (3) arranged displaceably therein along its longitudinal axis (2) for introducing and metering the gas flow into the combustion chamber of the internal combustion engine, characterized in that the injector valve needle (3) is linearly guided at at least one bearing point (11, 12) by balls (13, 14) arranged axially circumferentially in a recirculating ball guide (16, 17). The invention further relates to a gas injector for an internal combustion engine, comprising a housing (1) and an injector valve needle (3) arranged displaceably therein along its longitudinal axis (2) for introducing and metering the gas flow into the combustion chamber of the internal combustion engine, characterized in that the injector valve needle (3) is guided at two bearing points (11, 12) by rolling elements (32, 33) arranged in a linear guide (30, 31, 35, 36, 38, 39).

The present invention relates to a drive device (100) of a brake caliper (200), comprising a recirculating ball screw-nut assembly within a cylinder chamber (140) in a caliper body (145), wherein the recirculating ball screw-nut assembly comprises a threaded shaft (150) and a nut (160) screwed externally onto the threaded shaft (150), with external teeth (165) of the nut screw,wherein the threaded shaft (150) and the nut screw (160) extend in the direction of a drive axis (170) coaxial to the threaded shaft (150), and wherein the threaded shaft (150) extends in a direction of extension from a front end thereof to a rear end thereof to a thrust plate (180),in which an axial retaining ring (110) of the nut screw (160) is interposed between the external teeth (165) and the thrust plate (180) and held in position with the use of at least one fixing screw (120) comprising at least one respective tip (125),in which the axial retaining ring (110) has an inclined surface (111) on which a tapered side (121) of at least one respective tip (125) of at least one fixing screw (120) interferes.

The embodiment of the invention provides a vehicle deviation compensation control method matched with a recirculating ball steering gear and related equipment, and belongs to the technical field of vehicle control. The method comprises the steps that a vehicle state signal is obtained, and the starting state of a deviation compensation function is determined according to the effectiveness of the vehicle state signal; when the deviation compensation function is enabled, responding to the condition that the vehicle state signal meets a first preset working condition, and analyzing and determining a long-term compensation force and a short-term compensation force according to the vehicle state signal; and in response to monitoring that the vehicle state signal meets a second preset working condition under the first preset working condition, maintaining the long-term compensation force and the short-term compensation force, and applying compensation torque according to the long-term compensation force and the short-term compensation force through a power-assisted motor of the recirculating ball steering gear. The embodiment of the invention aims at enabling the vehicle matched with the recirculating ball steering gear to realize intelligent deviation compensation and reducing the driving fatigue of a driver.

A ball screw mechanism (1) has a screw (10) forming an inner helical raceway (24); a nut (12) forming an outer helical raceway (54), at least two balls (14) positioned so as to roll simultaneously on the inner and outer raceways, and also a first end-of-travel stop device (32) for the balls (14) and a second end-of-travel stop device (62) for the balls (14), these end-of-travel stop devices being axially opposite and delimiting with the inner helical raceway (24) and the outer helical raceway (54) a helical volume for housing the balls (14). The second stop device (62) has a second fastening portion (68) that is fixed relative to the nut (12), and the first stop device (32) has a first fastening portion (67) that is fixed relative to the screw (10).

The invention relates to the technical field of modeling and fatigue life checking of steering gear parts, and provides a method for creating a life checking template based on a steering screw nut pair model, which comprises the following steps of: 1, creating a fully parameterized steering screw nut pair model; step 2, creating a parameter setting window; step 3, preparing a steering load spectrum library; 4, preparing a whole vehicle service life, road condition, steering frequency and load distribution database; step 5, creating a strength and service life checking window; the strength and service life checking window comprises a load spectrum calculation area, a whole vehicle service life estimation area, a correction parameter setting area, a calculation result display area, a load and service life calculation button and a checking result display area; and step 6, based on a life fatigue test result, adjusting the life checking template. According to the method, the all-parametric model is created for the steering screw nut pair in the recirculating ball type steering gear, and the rapid modeling and strength and fatigue life checking template is created based on the all-parametric model, so that the design efficiency is improved.

The present application relates to the technical field of steering gear, and discloses a split type recirculating ball type electric power steering gear, which comprises an electric power steering assembly, a steering assembly which is detachably arranged at a driving end of the electric power steering assembly and forms a split type arrangement with the electric power steering assembly, and a positioning assembly which is arranged inside the steering assembly and used for coaxially connecting with the driving end of the electric power steering assembly, wherein the electric power steering assembly comprises a worm shaft which is rotatably arranged at one side of a speed reducer, a connecting disc which is fixedly arranged at an end of the worm shaft, a first coordination hole which is formed in the inner side of the connecting disc, and an input shaft which is rotatably arranged at the side of the speed reducer away from the connecting disc. The split type recirculating ball type electric power steering gear can effectively solve the problem that the connection between the worm shaft and the ball screw is not safe enough in the prior art.

This disclosure provides a system and method for driving multi-mode steering in a vehicle. The system includes a control subsystem, a front-wheel steering subsystem, and a rear-wheel steering subsystem. The control subsystem includes a vehicle controller, an intrinsically safe angle sensor, an intrinsically safe pressure sensor, and an onboard intrinsically safe display screen. The front-wheel steering subsystem includes a steering wheel, an explosion-proof steering motor column assembly, a steering drive shaft, a recirculating ball steering gear, a steering tie rod assembly, a front steering axle assembly, and a front wheel hydraulic circuit branch of a hydraulic pump station. The rear-wheel steering subsystem includes a rear wheel hydraulic circuit branch of a hydraulic pump station, an explosion-proof solenoid valve assembly, and a rear steering axle assembly. The technical solution of this disclosure achieves precise control of multi-mode vehicle steering, adapts to different driving scenarios, improves the flexibility and maneuverability of vehicle steering, and enhances the accuracy and reliability of steering control, ensuring a stable and controllable steering process, thereby improving driving safety and comfort.

The invention provides a novel driving unit based on a hub motor. The novel driving unit comprises a hub, the speed reduction type hub motor, an electronic mechanical braking system, a circulating ball pull rod electric control steering system, a disconnected type double-fork-arm suspension and a novel driving unit shell. The upper end of a steering knuckle of the recirculating ball pull rod electric control steering system is hinged to a suspension upper fork arm, the hinge point serves as an upper positioning point of a virtual steering main pin, the lower end of the steering knuckle is hinged to a disconnected suspension lower fork arm, and the intersection point of extension lines of the disconnected suspension lower fork arm serves as a lower positioning point of the virtual steering main pin. The virtual kingpin steers to release the internal size of a rim so as to facilitate the installation of a speed reduction type hub motor and an electronic mechanical braking system, and the offset distance of the kingpin is reduced to reduce the steering angle envelope and improve the steering portability; the axial size of the recirculating ball pull rod electric control steering system is reduced so as to improve large-turning-angle steering of the steering system. The novel driving unit shell serves as the unique connection of the novel driving unit and the frame, so that the integrity of the novel driving unit and the transportability of the novel driving unit among different vehicle types are improved.

The invention relates to the technical field of steering gears, in particular to an electric recirculating ball steering gear assembly which comprises a steering input electric control mechanism, a steering output sealing mechanism and a steering transmission mechanism. A steering transmission mechanism is installed on the inner side of the bottom end of the steering output sealing mechanism, the steering input electric control mechanism comprises a controller, a monitoring transmission wire harness is installed on the upper end face of the controller, and a worm is installed above the monitoring transmission wire harness. The steering gear is subjected to soft limiting, mechanical hard limiting is avoided, automatic zeroing after vehicle empty and full load neutral position deviation is achieved, meanwhile, an external guide pipe which is prone to impact deformation or abrasion to cause clamping of external circulation is omitted, and oil seal disengagement is avoided.

The present application relates to a combined guide rail mechanism and its use in a vehicle slide-out system, which includes a guide rail, a first guide, and a second guide. The guide rails contain multiple parallel rows of circulating balls, enabling the combined guide rail mechanism to achieve two-stage telescopic linear motion. A vehicle box slide-out system comprises the combined guide rail mechanism, a driving device, a support frame, a bearing box, and a slide-out box. This application achieves a two-stage extension, increases the usable space of the vehicle, and has an integrated mechanism setup that does not require disassembly of the vehicle's chassis. It is easy to install, needing only the slide-out box to be placed at the vehicle's opening, which is neat and aesthetically pleasing.

The utility model discloses a horizontally-installed integrated electromechanical recirculating ball steering gear which comprises a steering gear shell, a steering screw, an angle adapter assembly, an upper shell and an input shaft, the angle adapter assembly is arranged on the left side of the steering gear shell, and the steering gear shell is composed of a left shell body and a right shell body. The left shell and the right shell are horizontally and fixedly connected through bolts, angular contact bearings are arranged on the left side and the right side in the left shell respectively, one end of the steering screw is installed in the angular contact bearing on the right side, and the other end of the steering screw penetrates through the angular contact bearing on the left side to be connected with the output end of the angular adapter assembly. An upper shell is arranged at the input end of the angle adapter assembly; the steering gear adopts a horizontal mounting structure, and meanwhile, the angle adapter assembly and the angle torque sensor are deeply integrated, so that the angle torque sensor is closer to a steering wheel, and the accuracy of hand power monitoring of the sensor is improved, so that the control precision of the steering gear is improved, and the driving experience feeling is improved.

The present invention relates to a power assisted steering system arrangement (100A) for a vehicle, comprising a steering wheel (120A), a first driver linkage arrangement (10A), the first driver linkage arrangement (10A) comprising a linkage arrangement between the steering wheel (120C) and the front wheels (127, 127), the linkage arrangement comprising a steering column (121A), a recirculating ball joint (RCB) (123A) arranged on a first side of the vehicle, a tie rod arrangement for steering the front wheels (127, 127), a first lever arm (124A) arranged to transmit a torque applied by the driver via the steering wheel to the tie rod arrangement, the first lever arm (124A) providing a connection between the RCB (123A) and the tie rod arrangement. The system also includes: a torsion bar (128A) having a torsion bar torque sensor associated with a steering column (121A); an auxiliary actuator (30A) arranged on a second side of the vehicle, opposite to a side of the vehicle on which the RCB is arranged, the auxiliary actuator (30A) comprising at least an electric motor (115A) and an electronic control unit ECU (110A) which controls the electric motor according to a control signal received from the torsion bar torque sensor; and an auxiliary actuator linkage arrangement (20A) connected to a tie rod arrangement so that a steering torque applied by a driver and an auxiliary actuator torque provided or applied by the auxiliary actuator (30A) are transmitted to the tie rod arrangement for steering the front wheels of the vehicle.

A recirculating ball steering gear for a steering system of a vehicle, in particular a utility vehicle, includes at least one housing, at least one steering spindle, at least one steering spindle nut which is guided in an axially displaceable manner inside the housing and which in the assembled state is connected to the steering spindle via a plurality of balls, and at least one bearing device, by which the steering spindle is supported in the housing. The bearing device, the steering spindle and the housing form an adjusted bearing arrangement.

The invention discloses a structure and a method for improving performance of a recirculating ball steering gear for a commercial vehicle, and the structure is characterized in that a gradual change correction structure is arranged in a range of + / -150 degrees in the middle position of a steering screw rod and is divided into three correction intervals, a high friction torque area is formed through middle diameter local drum shape correction, and the middle position control precision is improved; a pitch line of a tooth groove of a middle tooth of the steering nut is lifted by 0.1-0.3 mm relative to pitch lines of teeth on the two sides, so that the meshing rigidity is enhanced; the middle tooth area of the rocker arm shaft is provided with a subarea gradual change correction structure, so that the meso-position meshing characteristic is clear and the wear resistance is high; according to the method, a grinding or tooth profile milling process is adopted to achieve accurate correction of a steering screw raceway and a steering nut tooth groove, and through collaborative design and parameter matching of a steering screw, a steering nut and a rocker arm shaft, the comprehensive performance of a whole vehicle steering system in the aspects of neutral position controllability, aligning performance and durability is optimized; the problems that a traditional recirculating ball steering gear is fuzzy in neutral position, stiff in control, large in return residual angle and the like are effectively solved.

The invention discloses a flexible limiting device of a hydraulic recirculating ball steering gear, which comprises a shell, an input screw is arranged in the shell, an upper end bearing is arranged at one end of the input screw, a lower end bearing is arranged at the other end of the input screw, a limiting boss is arranged outside the input screw, and the lower end bearing is arranged at the other end of the input screw. The shell is provided with a plurality of detachable flexible limiting stoppers, and the flexible limiting stoppers are matched with the limiting bosses. The hydraulic unloading device solves the problems that a hydraulic unloading device in an existing hydraulic recirculating ball steering gear is complex in structure, slow in response, large in impact and the like, boss limiting is achieved when the steering stroke reaches the limiting position through mechanical cooperation of the limiting boss and the flexible limiting stopper, a spring is used for buffering, a traditional hydraulic unloading device is replaced, and the reliability of the hydraulic recirculating ball steering gear is improved. And a flexible limiting function is realized.

The invention relates to an adjustment unit of a steering column of a vehicle, comprising: an adjustment device which has at least one adjustment motor; a pull-out device which has a pull-out carrier which is designed to be arranged in a rotationally and axially fixed manner on a body of the vehicle; and at least one inner pull-out element which is arranged in an axially movable manner in the pull-out carrier, wherein at least one bearing arrangement is provided between the at least one inner pull-out element and the pull-out carrier, wherein the at least one bearing arrangement is formed from a recirculating ball segment, wherein the at least one recirculating ball segment (1) is spring-loaded by means of a spring element (2), wherein the spring element (2) has a rounded central region (7).

The utility model discloses an electric recirculating ball steering gear structure easy to maintain, which comprises a recirculating ball shell, a steering lead screw and a steering rocker arm, the upper end of the steering lead screw penetrates from the lower end of the recirculating ball shell to the upper part of the recirculating ball shell, an upper angular contact bearing is arranged between the upper part of the recirculating ball shell and the recirculating ball shell, and a lower angular contact bearing is arranged between the lower part of the recirculating ball shell and the steering rocker arm. An oil seal is arranged on the outer side of the upper angular contact bearing, an adjusting nut is in threaded connection with a threaded hole formed in the lower end of the circulating ball shell, a lower angular contact bearing is arranged in the adjusting nut, the lower end of the steering lead screw is rotationally connected with the lower angular contact bearing, and the steering rocker arm is meshed with a steering nut of the steering lead screw. The device has the advantages of readjustment and quick maintenance and part replacement, is convenient to operate, and can be used for readjusting the pre-tightening force of the steering lead screw positioning angular contact bearing after the worm gear shell is assembled by arranging the adjusting nut structure at the tail part of the recirculating ball shell, so that the production maintainability of a production line is improved.

A retainer comprises a snap ring part substantially discontinuous-ring shaped with opposed ends defining a break to be fitted over an outer surface of a ball nut; and an outer race part of a ball return formed on an inner surface of the snap ring part to be coupled with an inner race part of the ball return, end portions of the outer race part of the ball return to be connected to openings of the ball nut for recirculating balls. The snap ring part is extended further than the end portions of the outer race part of the ball return around the outer surface of the ball nut such that the snap ring part retains the outer race part, formed on the inner surface of the retaining ring portion, on the outer surface of the ball nut to be coupled with the inner race part of the ball return.

The present application relates to the technical field of modeling and fatigue life checking of steering gear parts, and provides a method for creating a life checking template based on a steering screw and nut pair model, comprising the following steps: Step 1, creating a full-parameterized steering screw and nut pair model; Step 2, creating a parameter setting window; Step 3, preparing a steering load spectrum library; Step 4, preparing a vehicle life and road condition, steering frequency and load distribution database; Step 5, creating a strength and life checking window; the strength and life checking window comprises a load spectrum calculation area, a vehicle life estimation area, a correction parameter setting area, a calculation result display area, a "calculate load and life" button and a checking result display area; Step 6, based on the life fatigue test results, adjusting and calibrating the life checking template. The present application creates a full-parameterized model for the steering screw and nut pair in the recirculating ball steering gear, and creates a quick modeling and strength and fatigue life checking template based on the full-parameterized model, thereby improving the design efficiency.

The invention relates to an actuation device of a brake caliper, comprising a recirculating ball screw-nut assembly within a cylinder chamber in the caliper body, wherein the recirculating ball screw-nut assembly comprises a threaded shaft and a nut externally threaded onto the threaded shaft, the nut having an outer toothing of a nut screw, wherein the threaded shaft and the nut screw extend in the direction of a drive axis coaxial to the threaded shaft, and wherein the threaded shaft extends in the direction extending from a front end portion to a rear end portion thereof up to a thrust plate, wherein an axial retaining ring of the nut screw is placed between the outer toothing and the thrust plate and is held in place by using at least one fixing screw comprising at least one respective tip end portion, wherein the axial retaining ring has an inclined surface on which a tapered side portion of the at least one respective tip end portion of the at least one fixing screw interferingly engages.

The structure comprises a shell, a swing arm, a first eccentric bearing, a second eccentric bearing, a first blocking piece and a second blocking piece, and the first eccentric bearing, the second eccentric bearing, a first clamping spring groove, a second clamping spring groove, a first clamping spring and a second clamping spring are arranged in the shell. The bottom ends of the outer circumferences of the first O-shaped ring, the second O-shaped ring, the left side end dustproof oil seal, the output end dustproof oil seal, the first rocker arm shaft oil seal, the second rocker arm shaft oil seal, the first clamp spring groove and the second clamp spring groove are conical surfaces; according to the recirculating ball steering gear for improving the eccentric bearing structure, the problems of abrasion, failure and assembly interference of a sealing piece caused by axial movement of the eccentric bearing are solved.

The utility model discloses a commercial vehicle electric mechanical recirculating ball steering gear with a two-stage reducing mechanism, which comprises a worm and gear reducing mechanism and a ball screw pair which are arranged in a steering gear shell, and a transition connecting shaft, a planetary gear reducing mechanism and a driving motor are sequentially arranged at one end of a worm on the steering gear shell along the axial direction of the worm; the planetary gear speed reducing mechanism comprises a sun gear shaft, a plurality of planetary gear shafts are arranged in the circumferential direction of the sun gear shaft, an outer gear ring is arranged on the inner wall of a planetary gear speed reducer shell, a transmission disc is connected between rotating shafts of the planetary gear shafts, and a transmission shaft coaxially connected with the transition connecting shaft is arranged on the transmission disc. A rotating shaft of the sun gear shaft is fixedly connected with a rotating shaft of the driving motor through a first coupler, and the transition connecting shaft is fixedly connected with the worm through a second coupler. According to the utility model, heavy-load output of the steering gear can be realized; manufacturing cost is low, whole vehicle arrangement is facilitated, and the steering gear is convenient to maintain, disassemble and assemble; and the steering gear works stably and reliably.

The embodiment of the invention provides a delay assistance control method matched with a recirculating ball steering gear vehicle and related equipment, and belongs to the technical field of vehicle control. The method comprises the following steps: acquiring an IGN ignition signal, an engine signal, a vehicle speed signal and a historical assistance state of a previous period; determining a first input state according to the IGN ignition signal, determining a second input state according to the engine signal, and determining a third input state according to the vehicle speed signal; determining the power assisting state of the current period according to the first input state, the second input state, the third input state and the historical power assisting state, wherein the power assisting state comprises closing and activating; and in response to the fact that the power assisting state is activated, power assisting torque is determined according to the vehicle speed signal, and the power assisting torque is applied through a power assisting motor of a recirculating ball steering gear of the vehicle. The embodiment of the invention aims to improve the driving safety of the recirculating ball steering gear vehicle during accidental flameout.

The invention relates to a gas injector for an internal combustion engine, comprising a housing (1) and an injector valve needle (3) arranged displaceably therein along its longitudinal axis (2) for introducing and metering the gas flow into the combustion chamber of the internal combustion engine, characterized in that the injector valve needle (3) is linearly guided at at least one bearing point (11, 12) by balls (13, 14) arranged axially circumferentially in a recirculating ball guide (16, 17). The invention further relates to a gas injector for an internal combustion engine, comprising a housing (1) and an injector valve needle (3) arranged displaceably therein along its longitudinal axis (2) for introducing and metering the gas flow into the combustion chamber of the internal combustion engine, characterized in that the injector valve needle (3) is guided at two bearing points (11, 12) by rolling elements (32, 33) arranged in a linear guide (30, 31, 35, 36, 38, 39).

This invention relates to the field of frame equipment technology, and in particular to a recirculating ball type electric power steering system, comprising a steering power shaft; a steering assembly, mounted on the output end of the steering power shaft, which transmits signals through a Hella sensor after the steering power shaft rotates; a transmission mechanism, mounted on one end of the steering assembly, which provides power to the worm gear after receiving the transmitted signal; and a lubrication mechanism, mounted on one end of the transmission mechanism, which lubricates the threaded rod of the recirculating ball type mechanical steering system and simultaneously limits the movement of the threaded rod. It features light and flexible steering, active self-centering, autonomous driving, and assisted driving. Employing a Hella torque sensor capable of simultaneously outputting torque and angle signals, it offers more sensitive sensing, enabling not only active self-centering, autonomous driving, and assisted driving while ensuring power assist, but also light and flexible steering with a smooth and continuous feel.

The application discloses a kind of circulating ball type electric power steering system fault self-checking method, system and readable medium, it is related to vehicle technical field, including storage signal transmission path and each function node, determine the influence factor type that influence the precision of instruction execution at function node, the relationship between the fluctuation amplitude of data signal at each function node and the size of influence factor value is analyzed and obtained, as correction model, store the first relationship model for reflecting the data correlation between each function node on the same signal transmission path;Real-time data and source data of each type of influence factor are obtained, and theoretical response data is generated according to the first relationship model, real-time influence factor data and correction model;Actual response data is collected and the deviation amplitude between its and theoretical response data is calculated, whether the function node is failure or there is potential failure is determined according to the deviation amplitude, and early warning is output, the above technical scheme greatly improves the precision of fault detection and the pre-judging ability to potential failure.

The utility model discloses a variable pitch screw of an electric recirculating ball steering gear, which comprises a screw and a nut, a spiral raceway I is arranged on the outer circumferential surface of the middle of the screw, the pitch of the middle position of the spiral raceway I is larger than that of the two ends of the spiral raceway I, and the pitch of the middle position of the spiral raceway I is gradually reduced from the pitch of the two ends of the spiral raceway I to the pitch of the two ends of the spiral raceway I; an upper bearing mounting part, a worm wheel mounting part and a stator mounting part are sequentially arranged at the upper end of the screw rod, a spiral raceway I of the screw rod is matched with the nut, a lower bearing mounting part is arranged at the lower end of the screw rod, an input shaft limiting groove is machined in the upper end of the screw rod, a torsion bar hole is machined in the groove bottom of the input shaft limiting groove, and the input shaft limiting groove, the torsion bar hole and the screw rod are concentric; the structural design is simple, and the screw and the nut are designed to be of a variable-pitch structure, so that the electric recirculating ball steering gear is small in transmission ratio and flexible in rotation at the middle position; the transmission ratio is large and the output torque is large at the two ends, so that the output torque at the two ends of the product is improved.