465 results about "Tappet" patented technology

A damper assembly includes a housing having a tubular shape defining a main chamber extending along a center axis. A piston is movable along the center axis and divides the main chamber into a compression chamber and a rebound chamber. The piston includes a piston body defining a frequency-adaptive orifice (FAO) passage providing fluid communication between the compression chamber and the rebound chamber. The piston includes an FAO valve assembly having an FAO cover member configured to block fluid flow therethrough in response to application of a low-frequency excitation, and allowing fluid flow through the FAO passage in response to application of a high-frequency excitation. The FAO valve assembly also includes a tappet configured to translate relative to the piston body to bias the FAO cover member to selectively cover the FAO passage in response to the application of the low-frequency excitation.

The embodiment of the invention provides a variable lift rocker arm structure and a variable valve phase and lift rocker arm assembly structure, and relates to the technical field of rocker arms. According to the variable-lift rocker arm structure and the rocker arm assembly structure with the variable valve phase and lift, the variable-lift rocker arm structure comprising the rocker arm body and the auxiliary rocker arm structure is arranged, and the rocker arm body achieves switching of the extending position of the piston assembly through oil under the action of the auxiliary rocker arm structure; the first position is the first position or the second position, so that the first valve lift and the second valve lift generated by the valve are switched; on one hand, the eccentric wear influence on the tappets when double rollers or double tappets are switched in the prior art can be reduced to a certain extent; on the other hand, the number of parts is reduced, the mass is reduced, and the overall rotational inertia of the variable lift rocker arm structure is small.

A pneumatic valve comprises an actuator with a movable closing element being disposed in a housing; the closing element with a tappet penetrating an actuator opening between an air chamber formed in the housing and an actuator chamber, and a plate, with a sealing element, for closing the supply opening, thereon, on that end of said tappet protruding into the air chamber, and an elastic element pressing the plate toward the actuator opening in an activated state; the actuator element configured to move, in a non-energized state, the activating element to press the tappet against a supply opening, and in an energized state to move the activating element so as not to exert force on the tappet so that the plate is pressed in the direction of the actuator opening by the elastic element. A sealing collar disposed about the tappet seals the air chamber from the actuator chamber.

The following embodiments relate to air disc brake tappet and brake pad backing plate with interface features. In one embodiment, an air disc brake tappet is provided comprising: a top surface; and a support member coupled with the top surface; wherein the top surface comprises an interface feature that is configured to engage with a corresponding interface feature of a brake pad backing plate. In another embodiment, an air disc brake pad assembly is provided comprising: a friction material; and a backing plate coupled with the friction material; wherein the backing plate comprises an interface feature that is configured to engage with a corresponding interface feature of a top surface of an air disc brake tappet. Other embodiments are provided.

A method for manufacturing a semiconductor device (10), comprising: - a resin preparation step (S1) - for providing a tappet plate (32) in a hole (30a) formed in a recessed part (30A) of a lower mold (30), - for providing a first resin (20a) on the tappet plate (32), and - for providing a second resin (22a) having a lower thermal conductivity than the first resin (20a) on the first resin (20a); - a mounting step (S2) for placing a lead frame (12) on an upper surface of which a semiconductor chip (14) is mounted on an upper surface of the recessed part (30A); - a mold clamping step (S3) for placing an upper mold (40) on the lower mold (30), and for performing mold clamping in a state in which the semiconductor chip (14) is housed in a cavity formed by the lower mold (30) and the upper mold (40); - an injection step (S4) for lifting the plunger plate (32) after the first resin (20) and the second resin (22) have been melted to provide the second resin (22) in the cavity, and by subsequently introducing the first resin (20), the first resin (20) is brought into contact with a lower surface of the lead frame (12); and - a pressure maintaining step (S5, S7) for exerting a pressure on the first resin (20) and the second resin (22) through the plunger plate (32), and for maintaining the pressure.

The utility model discloses a double-diaphragm disc type brake chamber which comprises a front cover assembly, a middle body assembly and a cylinder body assembly. A push rod disc assembly is arranged between the front cover assembly and the middle body assembly, a first leather film is arranged between the push rod disc assembly and the middle body assembly, a dustproof sleeve is fixedly arranged on the front cover assembly and arranged on the outer side of the push rod disc assembly in a sleeving mode, and the cylinder body assembly comprises a second leather film, an aluminum release disc, a cylinder body and a release bolt. According to the double-diaphragm disc type brake chamber, due to the fact that the sealing assembly is arranged, hard friction between the tappet rod and the inner hole of the middle body is reduced, the service life of a product is prolonged, meanwhile, the tappet rod and the tappet rod disc are connected in a riveting pressing mode, the assembling technology is simplified, the assembling cost is reduced, and the potential risk that screws are loosened due to the fact that thread glue is not coated is avoided; center positioning of the release disc is increased through the parking cavity leather film, and damage to the release disc and the spring due to the fact that the leather film and the release disc are not positioned in the prior art when the parking cavity works is reduced.

The invention discloses a preparation process of a dual-material tappet with both wear resistance and toughness, and relates to the technical field of engine tappet manufacturing, the preparation process comprises the steps of matrix pretreatment, gradient heating, infiltration compounding, diffusion heat preservation, subsection cooling and finish machining, and a wear-resistant alloy material comprises the following chemical components in percentage by weight: 3.2-3.6% of C, 0.4-0.6% of Ni, 2.4-2.5% of Si, 0.9-1.3% of Cr, 0.6-0.9% of Mn and the balance of Fe and inevitable impurities. Mo is equal to 0.4%-0.65%, and Slt is equal to 0.1%, Plt; 0.1%, with the balance being Fe and inevitable impurities. Compared with the prior art, the method has the advantages that the performance can be flexibly matched according to different engine requirements; the comprehensive performance of the working face is remarkably improved by adopting an infiltration composite process; the strength and the toughness of the matrix are improved; the double-metal bonding strength is consistent; the cost of the infiltration composite process is lower than that of brazing; the matrix in the semi-molten state and the wear-resistant material form metallurgical bonding, and the bonding strength is higher; the combined steel and the gradient cooling process jointly improve the impact resistance.

A valve train assembly is provided for modifying a lift of at least one intake valve and / or exhaust valve. The valve train assembly includes at least one tappet that is housed in a rocker housing with at least one rocker lever. The at least one tappet is engaged to an actuator that is operable to change the tappet from a first configuration in which all cam lobe motion is imparted to the rocker lever for opening and closing the intake and / or exhaust valve, to a second configuration in which less than all motion of the cam lobe is transferred to the rocker lever.

An electromechanical brake actuator (10) for a brake of a vehicle (100) has a brake tappet (14) that can be moved substantially translationally for transmitting a compressive force (F) in the direction of a brake pad (6, 6′), a drive member (16) that generates a drive movement (A) and a coupling gear (18) that operatively connects the drive member (16) to the brake tappet (14). The coupling gear (18) converts the drive movement (A) of the drive member (16) into an adjustment movement (B) of the brake tappet (14). The coupling gear (18) has a coupling member (38) in contact with the brake tappet (14) that moves along a cam path (40, 60) and converts the substantially uniform drive movement into an adjustment movement (B) of the brake tappet (14) at, in portions, a non-uniform adjustment speed (B′).

Recess and protrusion features on a brake pad backing plate and an air disc brake tappet create a unique interface that keys the backing plate for use with the tappet. If the backing plate and / or tappet move during braking, the force applied by the protrusion of the tappet against the inner wall of the recess, or vice versa, can cause stress or damage to the backing plate, tappet, and / or other parts of the braking system. To accommodate such movement, the inner dimensions of the recess can be made greater than the outer dimensions of the protrusion. In one embodiment, the minimum dimensions of the recess are determined from a stack-up of tolerances of various components in the braking system. In another embodiment, maximum dimensions of the recess are determined to avoid overlapping step-down transitions in the backing plate and tappet during braking.

A regulating valve device for a fluid cylinder includes a shut off valve having a ball tappet that actuates the shut off valve. A lever has a cam surface that interacts with the ball tappet as the lever is rotated to translate the ball tappet linearly and actuate the shut off valve. The lever is rotatable from a first valve closed position through a valve open position to a second valve closed position such that the valve open position is intermediate of the first and second valve closed positions. A pressure or flow regulating valve is downstream of the shut off valve. A handwheel is operatively connected to the pressure or flow regulating valve to adjust an outlet pressure of the pressure or flow regulating valve. The handwheel has an axis of operation that is offset from a longitudinal axis of the fluid cylinder by an acute angle.

The invention discloses an engine hydraulic variable valve mechanism, an engine and a method, and solves the problem that in the prior art, a piston and a tappet do not move synchronously, so that the valve closing angle is greatly changed along with the change of the rotating speed when a valve mechanism is partially opened. The hydraulic variable valve mechanism of the engine has the beneficial effect that the closing angle of the valve cannot be advanced along with the change of the rotating angle of the crankshaft at different rotating speeds, according to the specific scheme, an oil drainage hole is formed in the side, close to a piston, of a shell, the piston blocks the oil drainage hole, and the oil drainage hole can be communicated with a piston cavity in the moving process of the piston in the piston cavity; a slide valve is arranged at the oil drainage hole, is arranged between the tappet and the piston through the shell and can be communicated or disconnected with the low-pressure cavity, the control oil way is provided with a power-off normally-closed electromagnetic valve, the power-off normally-closed electromagnetic valve controls the slide valve, when the power-off normally-closed electromagnetic valve is powered off, the slide valve cuts off the high-pressure cavity and the low-pressure cavity, and when the power-off normally-closed electromagnetic valve is powered on, the high-pressure cavity is communicated with the low-pressure cavity. And the air valve is in a partial opening state.

Device for fastening at least one magnet (14) in a magnet receptacle (22) of a rotor core (12, 46) of a rotor (10) of an electrical machine, with a receptacle (44) which is designed to receive the rotor core (46) at least temporarily, an adjusting unit (48) which is designed to carry out a lifting movement in order to thereby change a distance between a tappet (38) and the rotor laminated core (46) arranged on the receptacle (44), an embossing unit (42) arranged on the tappet (38), which has at least one punch (84), wherein the embossing unit (42) is designed such that the punch (84) penetrates at least partially into the rotor laminated core (46) in the region of the magnet receptacle (22) due to the lifting movement and the magnet (14) is clamped in the magnet receptacle (22) by the material deformation thereby occurring in the edge region of the magnet receptacle (22), and with a control unit (32) which is designed to process an adjustment path variable and a pressure force variable and to control the adjustment unit (48) as a function of the adjustment path variable and the pressure force variable, wherein the adjustment path variable represents the adjustment path by which the plunger (38) and the rotor laminated core (46) move towards one another due to the lifting movement, and the pressure force variable represents the force with which the punch (84) presses onto the rotor laminated core (46).

The present invention relates to a brake wheel cylinder, comprising a housing, a wedge, and a sleeve assembly. The sleeve assembly comprises a tappet, a sleeve, a screw, and a drive ring. A C-shaped spring and a winding spring are disposed between the tappet and the sleeve. Transmission balls are disposed on both sides of the wedge to cooperate with the tappet to achieve transmission. Inclined surfaces are formed on both sides of the wedge to cooperate with the transmission balls. Inclined surfaces are also formed on the side of the tappet to cooperate with the transmission balls. A ball retaining member is also disposed on the wedge to support a pair of transmission balls. The advantages of the present invention are that transmission balls are used as intermediate transmission between the wedge and the tappet, the transmission balls themselves can freely rotate 360 ​​degrees in any direction, and point-to-surface or line-to-surface contact can be achieved between the transmission balls and the wedge and tappet, thereby greatly reducing the contact area, avoiding the occurrence of jamming, and ensuring stable transmission.

The invention relates to a piston-integrated overflow valve located in a piston (50) of a working cylinder, comprising a first valve plunger (10) and a first actuating tappet (14), a second valve plunger (20) and a second actuating tappet (24), a spring element (30), a valve chamber (40) and an end bush (70). The valve plungers (10, 20) are axially slidable in the valve chamber (40) and each provide a closed position in a distal end position and an open position in a proximally axially offset working position. The valve chamber (40) has a hollow-cylindrical basic shape formed by an inner lateral surface of an axial bore (60) in the piston (50), wherein an end bush (70) is located in the axial bore (60) at at least one axial bore end (61) and is welded to the piston (50) along an outer bush ring face (72) by means of a circumferential laser ring weld (73), the circumferential laser ring weld (73) forming a pressure-medium-tight sealing plane.

A cam-driven valve assembly comprises a valve body that defines a plurality of fluid passages and supports a group of fluid valves within those passages to control fluid flow. The assembly includes a plurality of cams supported on a camshaft. The camshaft is arranged such that each cam is associated with a corresponding valve. Rotation of the camshaft actuates the valves via the cams. Each cam comprises a pair of cam discs that interact to define an inner cam track. A valve body for each fluid valve includes a cam tappet that is received in the cam track of a corresponding cam. The cam tracks can be configured such that at least one of the valves is actuated at a time different from the actuation time of another valve.

The utility model discloses a diesel engine tappet disassembling and assembling device which comprises a sleeve with a hollow structure inside. The push rod penetrates through the sleeve, the outer side face of the push rod is attached to the inner side face of the sleeve, and the sleeve can move in the length direction of the push rod; one end of the push rod is sleeved with the rubber body, the swelling amount of the rubber body is changed by changing the position of the push rod, and the rubber body is used for generating friction force with the inner wall of the tappet hole; according to the diesel engine tappet dismounting and mounting device, dismounting and mounting of the tappet can be facilitated, the dismounting and mounting efficiency is high, and the diesel engine tappet dismounting and mounting device is suitable for dismounting and mounting of the tappet under various conditions.

A pressure reducer (10) having: a housing (11) defining a front pressure chamber (13) and a rear pressure chamber (14); a valve (12) positioned in the housing (11), wherein the valve (12) has a diaphragm (16) acting on a valve tappet (15), on which diaphragm acts on the one hand a spring force of a spring element (17) acting in the opening direction of the valve (12) and on the other hand a force acting in the closing direction of the valve (12) and depending on the pressure present in the rear pressure chamber (14), and wherein the valve (12) has a valve body (22) fixed to the valve tappet (15), which valve body acts together with a sealing element (24). The valve body (22) is contoured cylindrically or hollow-cylindrically or conically in the case of a sealing surface (23) acting in the constructional radial direction. The sealing surface (23) of the valve body (22) is interrupted via a flow channel (26) at at least one circumferential position such that depending on the pressure loss present in the rear pressure chamber (14), either the sealing element (24) bears against the sealing surface (23) and completely closes the flow area (25) between the sealing element (24) and the sealing surface (23) including the corresponding flow channel (26), or the sealing element (24) moves away from the sealing surface (23) and completely releases the flow area (25) including the corresponding flow channel (26), or the sealing element (24) bears against the sealing surface (23) and only partially releases the flow area (25) via the corresponding flow channel (26).

The utility model discloses a tappet-free body type oil feed pump and an oil injection system, and relates to the technical field of oil injection systems, the tappet-free body type oil feed pump comprises a body with an oil cavity, the oil cavity at least comprises a first cavity body used for installing an eccentric cam assembly and a second cavity body used for installing an oil pumping assembly, the first cavity body is communicated with the second cavity body, and the first cavity body is communicated with the second cavity body. The oil pumping assembly comprises a plug sleeve installed in the body and a plunger movably connected in the plug sleeve, the plunger and the plug sleeve are elastically connected through an elastic piece, and the eccentric cam assembly makes contact with the plunger so as to jack up the plunger. Two large-mass parts, namely a tappet body and a spring lower seat, are omitted, so that the motion inertia caused by the unsprung mass of the plunger spring is effectively reduced, and the high-rotating-speed operation of the oil supply pump is favorably realized.

This invention belongs to the field of heat treatment, specifically a heat treatment device for an integrated ball-and-socket valve tappet with an anti-deformation structure. It includes: a material-holding mechanism for supporting the tappet within a heating furnace; and a limiting mechanism disposed on the material-holding mechanism for limiting the lugs at the top of the tappet, reducing deformation during heat treatment. The material-holding mechanism includes a material rack and at least one material tray disposed on the rack. The bottom of the material tray has a grid structure and multiple mounting holes that are interference-fitted with guide bodies for loading the tappet. The limiting mechanism includes a transmission mechanism and a limiter. By setting the limiter, the two thinner lugs on the tappet can be limited to reduce deformation during heat treatment. The mounting holes also allow the tappet to be placed vertically during heat treatment, reducing elliptical deformation of the top lugs due to gravity.

The application discloses a kind of wind turbine single blade installation process dynamic response analysis methods considering wind load action, comprising: according to the wind turbine blade installed and construction sea area, establish blade airfoil database and turbulent wind field database;When the position of lifting point and the position of tappet vertex are described, homogeneous transformation matrix is used to describe the motion of each mechanism of ship-mounted crane;When the position of lifting point is described, the position of tappet vertex is described, and the position of blade centroid in space is described by lifting point position, sling length and generalized coordinate;Wind load at each time point in the process of blade installation is obtained;The sling tension in the process of blade installation is obtained;The dynamics model of single blade installation system is established by using Lagrange method;The method can accurately analyze the coupling motion response between crane ship, ship-mounted crane, sling and blade in the installation process, and simultaneously by selecting generalized coordinate and modeling and analyzing the system based on energy method, the system modeling efficiency is effectively improved.

A vibration damper of a motor vehicle comprises an outer tube and an inner tube which is disposed so as to be coaxial with the latter, and a working piston which is disposed so as to be axially movable within the inner tube and divides the interior of the inner tube into a piston rod-proximal working chamber and a piston rod-distal working chamber, a damping valve device which is disposed in the working piston, wherein the damping valve device has: a coil, an axially movable armature which is at least partially disposed within the coil, a main valve having a main piston which separates a compression main control chamber, a traction main control chamber and a pilot control chamber from one another, a pilot valve which is designed in such a manner that it is able to be passed through by a flow of hydraulic fluid in the traction phase and in the compression phase and has a pilot working chamber and a sliding tappet that is disposed in the pilot working chamber and is axially movable by means of the armature, and a connecting duct which is disposed between the pilot control chamber and the pilot working chamber and fluidically connects those to one another, wherein the main piston comprises a cylinder base region and a cylinder casing region which forms the radially outer face of the main piston.

The invention discloses a valve tappet assembling device, which relates to the technical field of valve tappet assembling, and comprises a mounting rod, a magnetic attraction part, a first magnetic attraction part and a second magnetic attraction part, the disengagement rod is slidably connected to the mounting rod in a sleeving mode, a plurality of turning plates are rotationally arranged on the disengagement rod in a circumferential array mode, each turning plate comprises a duckbilled part and a cavity communicated with the duckbilled part, and the duckbilled parts are squeezed by movement of the turning plates so that the cavities can be blocked; the suction mechanism is communicated with the cavity and comprises a waste residue cavity formed in the separation rod. According to the valve tappet assembling device, the cavity is sucked through the suction mechanism, hydraulic oil scraped by the duckbilled part is sucked into the waste residue cavity, so that the outer wall of the valve tappet is cleaned, the hydraulic oil is prevented from staying between the outer wall of the valve tappet and the to-be-assembled mounting cavity, and under clamping of the duckbilled part, the valve tappet accurately enters the mounting cavity; therefore, the whole operation process is relatively simple.

The invention discloses a method for improving tire assembly quality, and relates to the technical field of tires. After the method is adopted, the problems of impurities in the tire, folding of the flap, eccentricity of the inflating valve, exceeding of the height of a seam allowance platform and the like in the tire assembling process can be avoided, the early quality problems of puncture and cutting of the impurities in the inner tire, extrusion damage of the flap, damage of the inflating valve and the like in the using process of the tire are prevented, and the using mileage of the tire is increased.

Pallet transport device, including: a mobile pallet transport rack; a pallet support arrangement which is carried on the pallet transport frame for a back-and-forth movement relative to the frame and comprises pallet supports which are spaced and shaped to accommodate and support pallets; a lifting frame fixed to the frame and containing guides shaped to support and guide the pallet carrier assembly by a reciprocating lifting and lowering motion, so that the pallet carrier assembly raises and lowers all pallets arranged to be supported by the pallet carriers; a drive machine which is supported by the frame and operatively connected to the pallet carrier assembly and configured to move the pallet carrier assembly by its reciprocating lifting and lowering motion; and a motion control system that is connected to the drive machine and configured to plan the reciprocating lifting and lowering motion of the pallet carrier assembly, wherein the motion control system comprises a mechanical linkage that operatively connects the drive machine to the arrangement, wherein the linkage comprises a cam that is driven by the drive machine and is shaped to plan the reciprocating motion of the arrangement via a movement of a cam tappet that is operatively connected to the arrangement.

Roller tappet (40) for a pump (1), in particular a high-pressure pump (1) for a high-pressure injection system for a motor vehicle for supporting a reciprocating pump piston (12) on a drive shaft (14), comprising a tappet body (8) for supporting a roller (46), a hollow-cylindrical roller (46), a bearing pin (52) arranged within the hollow-cylindrical roller (46) for supporting the roller (46), such that a radial bearing gap (38) is formed between the roller (46) and the bearing pin (52), a first lubricant channel (11a) formed in the tappet body (8) for supplying a lubricant to a first axial end region (29) of the roller (46) and / or the bearing pin (52), a second lubricant channel (11b) formed in the tappet body (8) for supplying a lubricant to a second axial end region (31) of the roller (46) and / or the bearing pin (52),wherein the roller tappet (40) comprises a movable actuator (2) for changing the flow cross-sectional area of the first and / or second lubricant channel (11a, 11b) in order to achieve a reliable supply of the volume flow (Q1) of lubricant conducted through the first lubricant channel (11a) and the volume flow (Q2) of lubricant conducted through the second lubricant channel (11b).

A plunger (1) for a high-pressure fuel pump is proposed, comprising a housing (2) from whose drive-side annular face (3) two radially recessed and diametrically opposed flanges (4) extend, in which a bolt (6) carrying a cam guide roller (5) is seated, the flanges (4) being shell-shaped on their underside (8) facing a driven-side annular face (7) of the plunger (1), the housing (2) being axially penetrated below the cam guide roller (5) by a separate bridge piece (9), the lower face (10) of which inherently provides a receptacle for a plunger follower, and the upper face (12) of which is complementarily arched in outer areas (13) at the undersides (8) of the flanges (4) and abuts the flanges (4) with these outer areas (13), the two outer areas (13) of the bridge section (9) are each provided with a stress relief notch (14) at the apex.

The utility model relates to the technical field of engines, in particular to an engine valve tappet layout structure which comprises a cam shaft arranged in an engine box body, tappets are arranged on the engine box body and correspond to two valve cams arranged on the cam shaft in pairs, the upper ends of the tappets are used for being connected with valve push rods, and the lower ends of the tappets are used for being connected with valve push rods. The upper ends of the valve push rods extend upwards and are arranged on a cylinder cover above an engine cylinder head; an oil pump is arranged on the engine box body and corresponds to a pressure supply cam arranged on the cam shaft, and the pressure supply cam is matched with the pressure supply end of the oil pump. The paired two valve cams are arranged at one end of the cam shaft, and the pressure supply cam is arranged at the other end of the cam shaft. The utility model has the characteristics that the structural design is simpler and more reasonable, the layout is more compact, and the working reliability can be improved.

The utility model relates to a light-weight automobile brake valve wide in application range, and relates to the technical field of automobile parts, the light-weight automobile brake valve comprises a valve body and a pedal rotationally arranged on the valve body, a valve element assembly used for controlling brake of the valve body is arranged in the valve body, and a tappet is vertically arranged on the valve body in a sliding mode; the bottom end of the tappet is connected with a valve element assembly in the valve body, the top end of the tappet abuts against the lower surface of the pedal, and an adjusting device used for adjusting resistance generated when the pedal rotates is arranged on the valve body. The moving mechanism is started to drive the friction cushion block to move, the friction cushion block makes contact with the side wall of the tappet under the action of the moving mechanism, and the resistance, caused by the friction cushion block, to moving of the tappet is controlled by adjusting the contact strength between the friction cushion block and the tappet; therefore, different drivers can adjust the moving mechanism to enable the force required for treading the pedal to meet self requirements, and the application range of the pedal of the brake valve to different people is expanded.

The present invention provides a tappet hole repair tool and a method for repairing the tappet holes of a diesel engine body in a confined space, which relates to the technical field of diesel engine repair. The problem that it is difficult to repair the tappet holes of a diesel engine body in a confined space and it is difficult to ensure the machining accuracy in the prior art is solved. The through holes of the fixing plate of the present invention are arranged according to the tappet holes and stud holes of the diesel engine body. The center of the tappet hole is determined by the cooperation of the conical positioning part of the positioning sleeve and the mating hole of the body. The position of the fixing plate relative to the tappet hole is ensured by the clearance fit between the cylindrical positioning part of the positioning sleeve and the first through hole of the fixing plate. The position of the tool center relative to the tappet hole is ensured by the clearance fit between the tool shank of the special tool and the third through hole of the fixing plate of the positioning sleeve, ensuring the machining accuracy of the tappet hole and the bushing, and obtaining a tappet hole that meets the requirements. Compared with the prior art, the present invention can be conveniently brought into the confined space to assist in the repair of the tappet hole to reduce the difficulty and can ensure the machining accuracy of the tappet hole.