31results about How to "Reduce jumping" patented technology

This utility model relates to the technical field of blister trays, and in particular to a blister tray with a TPU cushioning pad, which cushions the movement of products during transportation and improves the strength of the tray when the product is heavy; it includes a tray body, multiple tray bodies can be stacked together; it also includes a TPU pad, an upper support surface, a lower support surface, and a sloped surface. The TPU pad is disposed on the bottom edge of the tray body, the upper support surface is disposed on the top surface of the tray body, the lower support surface is disposed around the outer side wall of the tray body, and the four sides of the tray body are set as sloped surfaces.

The present application relates to the technical field of positive displacement fluid machinery, and particularly relates to a low-noise three-screw rod pump and a ship hydraulic system. The low-noise three-screw rod pump comprises a new active screw rod, a positioning sleeve, two new driven screw rods, and a smooth section. The positioning sleeve is provided on the smooth section of the new active screw rod in an interference fit. The positioning sleeve is provided with an annular limiting groove. The two new driven screw rods are symmetrically matched with the new active screw rod. The front end of the new driven screw rod is provided with a cylindrical guide section. The cylindrical guide section is rotatably embedded in the annular limiting groove. The circumferential surface of the cylindrical guide section is provided with a tapered oil guide surface. The tapered oil guide surface is clamped between the inner wall of the bushing and the annular limiting groove with a set radial gap. The low-noise three-screw rod pump and the ship hydraulic system solve the technical problems of vibration noise increase caused by the large axial installation gap and the radial thermal expansion and jamming.

The invention belongs to the technical field of building interior wall detection, and discloses a building interior wall verticality detection device, which comprises a movable rack, a detection mechanism, a detection mechanism and a control mechanism, and is characterized in that the movable rack is provided with a guide mechanism for moving in a manner of being attached to a wall surface; and the gravity sensing assembly is pivoted in the movable rack and comprises a pendulum bob which generates relative swing along with the inclination of the movable rack, and a triggering magnetic piece is arranged at the lower end of the pendulum bob. The inclination state of the movable rack is sensed in real time through cooperation with the gravity sensing assembly, the detection process can be continuously carried out when the movable rack moves along a wall, the operation burden caused by point-by-point staying alignment and visual inspection reading is reduced, the inspection efficiency is improved, the pendulum bob and the triggering magnetic part are adopted as inclination triggering sources, and the detection accuracy is improved. The triggering displacement is realized by utilizing the magnetic force action of the stress magnetic piece and the impact piece, so that the triggering process is mainly based on magnetic force coupling, the frictional wear and clamping stagnation probability of a pure mechanical shifting structure is reduced, and the long-term stability of a triggering threshold value is favorably kept.

The present application belongs to the field of lithium battery SOC calculation, and particularly relates to a lithium battery SOC estimation method based on high-precision ampere-hour integral algorithm. The method comprises establishing an ampere-hour integral mathematical model and solving, and performing Taylor expansion on the solution; the average slope is obtained by means of linear combination of three-point slope by investigating the slope of two points in the interval, so as to ensure that the precision of the third-order Taylor expansion formula and the equivalent formula is the same. When the algorithm is executed, the charge state and the capacity value are initialized first, then the sampling time is obtained according to the sampling frequency, and then the relevant parameters are calculated according to the current sampling value, and finally the current SOC is calculated according to the specific value and the three slopes and is iterated in a loop. This method can improve the ampere-hour integral precision, and weaken the cumulative error and SOC jump.

The utility model discloses a steel pipe shaping machining device, and relates to the technical field of steel pipe machining equipment. The shaping mechanism is mounted on the base; the limiting mechanism is mounted on the base, and the limiting mechanism is located in the shaping mechanism; the limiting mechanism comprises at least two center frame assemblies which are installed on the base at intervals; the clamping assembly is installed on the base and located on the outer side of the center frame assembly; and the limiting assembly is installed on the base, and the bottom of the limiting assembly is matched with the top of the clamping assembly. The technical problem that in the prior art, the shaping machining quality of a long steel pipe cannot be fully guaranteed is solved.

An arm assembly and humanoid robot, the arm assembly comprising a first housing, a first driving mechanism, a second housing, a second driving mechanism and a first cable, the first housing comprising a main body shell, a first cantilever and a second cantilever, the main body shell having a first space, the first cantilever and the second cantilever being connected with the main body shell; the first driving mechanism comprising a first driving member, the first driving member being accommodated in the first space; the second housing being rotatably connected with the first cantilever, the second cantilever and the first driving mechanism, the second housing having a second space; the second driving mechanism comprising a second driving member, the second driving member being accommodated in the second space; the first cable being connected with the first driving member and the second driving member, a first wire channel of the first cantilever being in communication with the first space, a second wire channel of the second housing being in communication with the second space and the first wire channel, the first cable being arranged in the first wire channel and the second wire channel, so as to avoid the first cable from affecting the freedom of movement of the arm.

The application provides a saw blade with staggered saw teeth, a saw blade production process and equipment, and relates to the technical field of composite material cutting processing. The saw blade with staggered saw teeth comprises a circular saw body, a plurality of first saw tooth portions and a plurality of second saw tooth portions are staggered along the circumferential direction on the outer periphery of the circular saw body, the first saw tooth portions and the second saw tooth portions are equal in number and are arranged in sequence with intervals, the first saw tooth portions and the second saw tooth portions are staggered with each other, so that staggered cutting structures are formed between adjacent different types of saw teeth. The structure is beneficial to dispersing cutting force, reducing the load of a single saw tooth, improving the stability and durability of the saw blade, and facilitating the fracture and discharge of chips, thereby improving the cutting efficiency and processing quality.

The utility model relates to a kind of conveying stabilizing device for rubber steel wire material belt detection, for conveying and stabilizing rubber steel wire material belt, the conveying stabilizing device includes installation base, further include installation on the installation base and along the rubber steel wire material belt feeding direction sequentially set feeding mechanism, material belt stabilizing mechanism, discharging mechanism, the material belt stabilizing mechanism includes the roller located below the rubber steel wire material belt and the floating Y type double press wheel located above the rubber steel wire material belt, the roller and floating Y type double press wheel closely adhere to the rubber steel wire material belt.Compared with prior art, the utility model has the advantages of improving the stability, reliability and efficiency of rubber steel wire material belt continuous production.

The utility model discloses a windshield wiper structure of a cab assembly, which comprises a rotating motor, a protective baffle is arranged at the top of the rotating motor, a driving gear is arranged at the top of the rotating motor, and a rotating shaft is fixedly connected to the top of the driving gear. A corresponding rotating shaft is arranged at the bottom of the transmission gear, the windshield wiper assembly is based on the structure of the windshield wiper assembly and a rotating motor, connecting rod structures formed by a first switching rotating block, a connecting plate, a second switching rotating block, a rotating base and a rotating plate are driven to be combined with one another, and the basic reciprocating use function of the windshield wiper is achieved. And the windshield wiper assembly can effectively avoid the situation that pressure is not uniform during rotation in the using process through the structure of the windshield wiper assembly, so that the functionality of the device is further improved, the windshield wiper assembly is combined with the cleaning assembly to clean the surface of the windshield wiper arm when not in use, and dirt shellac residues are prevented.

This application discloses an emergency line switching method, system, and interaction method for a dual-exit cigarette sorting line, belonging to the field of computer technology. The method includes: continuously monitoring the equipment operation data of the dual-exit cigarette sorting line to obtain fault monitoring results; suspending the sorting operation of the sorting line and the inbound / outbound operations of the spare parts warehouse based on the fault monitoring results; transferring unsent orders from the faulty side to the normal side for cross-sorting based on the fault monitoring results, resuming the sorting operation until the replenishment status of the cigarettes already shipped on the replenishment line meets a preset first condition; obtaining the minimum unsent sorting serial number and initializing the replenishment line and sorting line; and rescheduling the unsent orders based on the minimum unsent sorting serial number and the fault monitoring results to complete the emergency line switching. The embodiments of this application facilitate rapid and flexible emergency line switching of dual-exit cigarette sorting lines, meeting the timeliness requirements of tobacco logistics.

The present disclosure describes a measurement force control system for controlling a measurement force acting on a measured object generated by a probe contacting the measured object, comprising a measuring rod, a supporting mechanism, a magnet, a magnetic conductor, at least one coil wound on the magnetic conductor, and a control module; the probe and the magnet are fixedly arranged on the measuring rod, the measuring rod is rotatably arranged on the supporting mechanism and drives the magnet to move along a preset motion path when the measuring rod rotates, at the same time, the probe contacts the measured object, the magnetic conductor is fixedly arranged relative to the supporting mechanism and is configured to form a magnetic loop inside the magnetic conductor for the magnetic field generated by the magnet, and the coil wound on the magnetic conductor forms a preset area covering the preset motion path of the magnet, the control module is configured to control the force acting on the magnet generated by the coil according to the material of the measured object, and further control the measurement force acting on the measured object by the probe on the measuring rod. According to the measurement force control system of the present disclosure, a relatively constant measurement force can be obtained.

The utility model relates to the technical field of dust fall and noise reduction of fans, and discloses a low-noise anti-abrasion fan structure for an air source heat pump, which comprises a casing and a partition plate fixedly connected in the casing, a dustproof mechanism and a support centering mechanism are arranged in the casing, the dustproof mechanism is arranged on the outer side of the support centering mechanism, and the support centering mechanism is arranged on the outer side of the casing. The dustproof mechanism comprises a box door, the box door is fixedly connected to one side of the machine shell, a sliding base is fixedly connected to the outer side of the machine shell, air ports are formed in the upper side of the machine shell and the interior of the box door, dust isolation plates are arranged on the upper side of the machine shell and the right side of the box door, and the supporting centering mechanism enables hydraulic pressure to support the output end of the motor. Therefore, the jumping condition of the output end of the motor is reduced, noise is reduced, the stability of the fan is improved, the dustproof mechanism effectively prevents dust and moisture from eroding the interior of the fan through the movably-arranged blocking block and an elastic structure in a matched mode, and the service life of the fan is prolonged.

This utility model relates to the field of finished paper cup conveying technology, specifically a finished paper cup conveying equipment for paper cup production. It includes a conveyor frame with a conveyor belt. An auxiliary device is provided on the surface of the conveyor frame, comprising two sets of slides fixed to the surface of the conveyor frame, each set containing two slides. A slider is slidably connected to the surface of each set of slides, and a limit plate is fixedly connected to the surface of the slider. Multiple rollers are rotatably connected to the surface of the limit plate, and the rollers are inclined. This utility model, by setting up the auxiliary device and using the two sets of limit plates in conjunction with the inclined rollers, can limit the movement of the paper cups on both sides, reducing deviation. Simultaneously, the baffles on the limit plates can intercept the paper cups, reducing bounce. Furthermore, through the adjustment unit and positioning unit, the baffles and limit plates can be adjusted to adapt to different paper cup transport methods, significantly improving the practicality and applicability of the entire device and enhancing its overall usability.

The invention discloses a data processing method and device for motion capture, electronic equipment and a storage medium, and the method comprises the steps: obtaining recording data of motion capture, and carrying out the posture calibration of the recording data, and obtaining calibration data; performing interpolation completion and filtering on the calibration data to obtain first data; performing biological constraint processing on the first data to obtain second data; performing displacement prediction on the second data based on a pre-trained displacement prediction model to obtain third data; and simulating and optimizing the third data based on a generative neural network to obtain motion capture data. According to the embodiment of the invention, the lost data frame is complemented by performing interpolation, inter-joint interpolation and the like on the data captured by the motion, and the latest data is filtered, so that the condition of data jumping is reduced; based on a pre-trained displacement prediction model, an applicable scene can be expanded; and the recorded data is simulated through the generative neural network, so that the motion capture data which is complete in data, better in continuity and higher in data frame rate is generated.

This invention relates to a diamond abrasive tool based on additive manufacturing, belonging to the field of diamond abrasive tools. It includes: grinding discs, a frame, and a tool substrate. The frame is a ring-shaped structure obtained through additive manufacturing and is fixedly mounted on the end face of the tool substrate. Multiple grinding discs are circumferentially spaced and fixedly mounted on the frame. The frame has various functional structures. This invention focuses on the additive manufacturing of the non-working layer structure in diamond abrasive tools, and does not involve the arrangement, holding, or bonding processes of diamond abrasive grains. The grinding component is a commercially available or separately prepared functional unit containing diamond abrasive grains. It provides an efficient and economical installation and support solution for the grinding component, achieving a multifunctional composite structure with optimized performance.

This invention provides a model-free smooth transition control method for aero-engine mode switching, belonging to the field of aero-engine control. First, a design method based on linear active disturbance rejection control (ADR) is introduced into the aero-engine control system for real-time estimation and compensation of unmodeled dynamics and external disturbances. The time-scheduled ADR controller is divided into a transition controller and a steady-state controller based on the operating time interval. Furthermore, by considering the actual operating time interval of the aero-engine control system, a time-scheduling parameter is introduced to dynamically adjust the maximum number of updates within the operating time interval of the time-scheduled ADR controller. Finally, stability analysis is performed on the switching dynamic error system of the time-scheduled system. By designing time- and switching signal-dependent multi-discontinuous Lyapunov functions, sufficient conditions are derived for the time-scheduled switching dynamic error system to maintain asymptotic stability under the average dwell time constraint.

The utility model discloses an end socket reinforcing ring automatic welding fixing device which comprises a rotating bottom plate, a fixed core seat and a self-aligning clamp, the fixed core seat is fixedly installed at the center position of the rotating bottom plate and comprises a base, an end cover, a pressing plate and a pressing bolt, the base is fixed on the rotating bottom plate, the top end of the base is fixedly connected with the end cover, and the pressing plate is fixedly connected with the self-aligning clamp. The end cover is in threaded connection with a compression bolt, the pressing plate is fixed to the end cover through the compression bolt and clamps a workpiece end socket, a plurality of aligning clamps are evenly arranged on the outer edge of the rotating bottom plate in the circumferential direction, each aligning clamp comprises a fixing block and a chuck, a clamping block is fixedly installed at the bottom of each fixing block, and the clamping blocks are correspondingly connected with the rotating bottom plate in an inserted mode. The chuck comprises a chuck upper portion and a chuck bottom, the chuck bottom is fixedly connected to the rotating bottom plate, the chuck upper portion slides front and back along the chuck bottom, a mounting hole is formed in the chuck upper portion, an adjusting shaft is rotationally connected into the mounting hole, and the adjusting shaft is in threaded connection with the fixing block. The automatic welding device is used for achieving automatic welding of a single end socket reinforcing ring.

The application discloses a multi-data-source-based airborne collision avoidance system mixed monitoring S-mode target track fusion method, which comprises the following steps: an airborne collision avoidance system carried by an aircraft acquires DF0 and DF16 messages which are replied by S-mode transponders around the aircraft and extended interrupted oscillation DF17 messages which are broadcast by an ADS-B OUT device, and stores the messages into a track chain table; assuming that track information of a tracked target aircraft is stored into a track chain table; tracks in the track chain table are traversed, and the track in the track chain table is used to update a corresponding track of the target aircraft in the track chain table. The application reduces the display prompt conveying error to pilots due to target jump, and achieves the purpose of reducing the burden of pilots operating the aircraft.

This application relates to a rock fracture gas collection system, belonging to the field of rock mechanics experimental technology. It includes a pressure chamber; a medium loading chamber disposed within the pressure chamber, the medium loading chamber having a medium inlet and outlet; a heat-shrinkable sleeve disposed within the medium loading chamber, forming a sample loading space; a pressure head disposed within the medium loading chamber and connected to the first end of the heat-shrinkable sleeve, the pressure head having a first gas collection hole communicating with the medium loading chamber; a pressure base disposed within the medium loading chamber and connected to the second end of the heat-shrinkable sleeve, having a second gas collection hole communicating with the medium loading chamber; and a gas detection device, the gas detection device being connected to both the first and second gas collection holes. This application can completely capture gas parameters throughout the entire cycle from rock loading to fracture, and can reveal the law of rock stress fracture-gas release, providing reliable data support for tunnel gas hazard risk assessment, early warning, and the formulation of prevention and control measures, thereby improving the level of engineering safety.

The utility model discloses an inclined porcelain eye yarn jumping prevention yarn blocking device, which relates to the technical field of yarn equipment, and is characterized by comprising a plastic main body, the plastic main body is detachably connected with a porcelain eye, and the porcelain eye is provided with a through hole for a yarn to pass through. The top surface of the plastic main body is provided with an inclined limiting ring for accommodating the embedding of the porcelain eye, the inner wall of the limiting ring is provided with a horizontal limiting strip, the outer wall of the porcelain eye is provided with an annular groove for accommodating the embedding of the limiting strip, and the porcelain eye is fixed with the limiting ring by embedding the limiting strip into the annular groove. Through the eccentric arrangement of the upper hole and the lower hole of the porcelain eye in the vertical direction and the inclined installation mode of the porcelain eye, movement of yarn can be effectively restrained, jumping of the yarn in a complex movement state is reduced, the yarn cannot jump out of a detection area when the yarn is suddenly accelerated or stopped, and the detection accuracy is improved. Therefore, the yarn state monitoring accuracy and reliability are improved.

The application provides a soft soil foundation road culvert settlement control method, which comprises the following steps: a calculation step, wherein a target object is subjected to soft foundation treatment, and post-construction settlement of the target object is calculated, the target object comprises a box culvert and a roadbed; a determination step, wherein a transition section is arranged at a joint of the box culvert and the roadbed, a length of the transition section is calculated according to post-construction settlement of the box culvert and post-construction settlement of the roadbed, and settlement parameters of the box culvert and the roadbed are determined. In the application, post-construction settlement of the box culvert and the roadbed is calculated first, then a transition section is arranged at a joint of the box culvert and the roadbed, the length of the transition section is calculated according to post-construction settlement of the box culvert and post-construction settlement of the roadbed, and settlement parameters of the box culvert and the roadbed are determined, construction is carried out according to the settlement parameters of the box culvert and the roadbed, the settlement difference at the joint of the box culvert and the roadbed can be effectively reduced, bumping and cracks caused by uneven settlement at the joint of the box culvert and the roadbed are reduced, the construction quality and safety of the road are improved, and the traffic comfort at the box culvert is ensured.

The utility model discloses an electronic multi -arm opening device reading arm stop gear relates to opening device technical field, it includes: reading cam, installation support is located the outside of reading cam, reset mechanism is set up on installation support, and the end of reset mechanism is in contact with the outer edge of reading cam, the upper reading arm is cooperated with reading cam one end, and is cooperated with reset mechanism the other end, the lower reading arm is cooperated with reading cam one end, and is cooperated with reset mechanism the other end, reset mechanism includes: reset guide rod, and is movably set up on installation support, limit shaft is installed on reset guide rod, reset spring is sleeved on reset guide rod, and reset spring is located in the inside of installation support, and roller bearing is installed on the end of reset guide rod, and the outer edge of roller bearing is in contact with the outer edge of reading cam. The utility model solves the technical problem of the inconsistent distance of the stop structure in the prior art to the reading arm, which is easy to cause the wrong flower phenomenon.

The application discloses a method for reducing the jump and noise of a saw blade base body, and relates to the technical field of saw blade base body production. The method comprises the following steps: S1, making a viscous damping material; S2, injecting the viscous damping material into a glue cylinder of a glue dispenser; S4, inserting a plug into each outer port of each sound reduction groove of the saw blade base body; S5, injecting the viscous damping material into a first sound reduction groove of the saw blade base body; S7, taking the saw blade base body away from a machine table of the glue dispenser, and then placing the saw blade base body filled with the damping material into an oven, baking the viscous damping material in the sound reduction groove through the oven, and obtaining a first saw blade base body filled with the damping material; and S8, repeatedly performing the steps S3-S7 multiple times, so as to obtain multiple saw blade base bodies filled with the damping material. The application has the beneficial effects of reducing the jump and noise of the saw blade base body and prolonging the service life of the saw blade base body.

This utility model relates to the field of cutting saw blade technology, and discloses a special saw blade for cutting ultra-thin diamond mesh window screens. It includes a mounting base, with a cutting structure located in the middle of the outer wall of the mounting base. The cutting structure includes a saw plate, and multiple saw teeth are fixedly connected to the outer wall of the saw plate. Flat cutter heads and arc-shaped cutter heads are respectively fixedly connected to the outer walls of the saw teeth. Both the upper and lower surfaces of the cutting structure have heat-conducting structures on their outer walls. In this utility model, the saw blade has a heat-conducting structure. Guided by the heat-conducting strips, the heat absorbed by the heat-conducting plates on the saw teeth can be transferred to the annular heat sink, thereby reducing the rate of temperature rise of the saw teeth and minimizing cutting errors caused by thermal softening, thermal deformation, and thermal expansion. Furthermore, the aluminum alloy heat-conducting strips and plates provide auxiliary reinforcement to the saw plate and saw teeth, thereby improving the overall toughness and stability of the saw blade and enhancing its safety during use.

The application relates to the communication technical field, and discloses a receiving end equalizer adaptive method and circuit of a high-speed serial interface chip, which comprises the following steps: a digital equalizer receives an output value of an analog-to-digital converter and coefficients of each node output by an adaptive algorithm module; the output value of the analog-to-digital converter is multiplied by the coefficients of the corresponding node and then added by the digital equalizer, and the result is output; a decision device judges the output of the digital equalizer and obtains decision data; the error between the decision data and an ideal value is calculated to obtain a preliminary error value; the adaptive algorithm module compares the preliminary error value with a dead zone threshold and determines a used error value, when the preliminary error value is within the range of the dead zone threshold, the used error value is 0, and when the preliminary error value is outside the range of the dead zone threshold, the used error value is equal to the preliminary error value. By setting the error dead zone threshold, the coefficient updating is stopped under certain conditions, and the power consumption is reduced under the premise of not excessively affecting the performance.

The application relates to the technical field of bearing machining equipment, improves the problem that workpieces are prone to jumping during centerless grinding, and discloses a bearing ring grinding device which comprises a rack, a grinding wheel arranged on the rack, a guide wheel and a cooling mechanism, a jump-preventing mechanism and a bracket for supporting a workpiece are arranged between the grinding wheel and the guide wheel; the bracket comprises a supporting plate; the jump-preventing mechanism comprises an air suction pipe, an air outlet pipe, a first fan connected with the air suction pipe and a second fan connected with the air outlet pipe, a top surface of the supporting plate is provided with an air suction groove, one end of the air suction pipe far from the first fan is communicated with the air suction groove, and an air outlet of the air outlet pipe is arranged above the rack and close to the direction in which the workpiece enters. When the bearing ring passes through the bracket, the first fan generates suction to the bearing ring in the direction close to the bracket through the air suction groove, so that the jumping of the bearing ring is reduced, the second fan separates the arranged bearings through the air outlet pipe, the mutual influence between the bearing rings is reduced, and the rotary precision of the bearing ring grinding can be improved.

The application relates to the technical field of road construction, in particular to a simple device for slide form construction of a road shoulder, which comprises a slide form and a counterweight, the slide form slides along a road during use, a road shoulder forming space is formed on the slide form, and a feeding port for conveniently pouring concrete is arranged on the side wall away from the road; and the counterweight is arranged on the slide form and used for increasing the gravity of the slide form. The application has the effect of reducing construction cost.

The utility model discloses a kind of spring winding machine core shaft anti-jumping mechanisms, comprising: bottom plate, swing subassembly is arranged on the bottom plate;The bottom plate below is provided with sliding assembly, drive the swing subassembly moves along the setting direction of the sliding assembly;The swing subassembly is set below silk outlet, the silk outlet moves along with the vertical direction of the sliding assembly, and contact with the swing subassembly, to limit the core shaft of the silk outlet.By swing subassembly is arranged below silk outlet, make core shaft and swing subassembly contact, when winding spring, it can swing back and forth to adapt to the core shaft of different size specifications on spring winding machine, and limit the core shaft by first bearing and second bearing, reduce jumping, solve the problem that uneven winding is caused by core shaft jumping in long-stroke winding, improve the qualified rate of product.

This utility model discloses a mechanical expansion shaft. The utility model includes a piston block and a shaft tube. Along the circumferential direction of the shaft tube, several expansion keys are movably connected to the shaft tube. The expansion keys are configured to extend a predetermined distance radially. The bottom of each expansion key has an inclined surface. The piston block has a wedge surface adapted to the inclined surface. One end of the shaft tube is elastically connected to the piston block, and the other end of the shaft tube forms a piston cavity with the piston block. The shaft tube has an air passage communicating with the piston cavity. This design combines high load capacity and low vibration while adapting to high-speed switching and suitable for coil positioning in various scenarios.

This application relates to a brush structure that slides in axial contact with a motor shaft, belonging to the field of electric motors. A brush component 3 is disposed on the end face of the first or both ends of the motor shaft 22 along its axial direction. The motor shaft 22 has a protruding structure 24 or an overall smooth recessed structure 26 along its rotation axis 25. Through the convex-concave fit between the motor shaft 22 and the contacting brush 33, the material fit strength of the brush 33 can be improved, the service life of the brush 33 can be increased, and the axial and radial runout of the motor shaft 22 can be reduced.