Automobile screw heat treatment equipment and technology for double oil quenching and low-temperature tempering

Abstract

The invention relates to the technical field of heat treatment equipment, in particular to double-oil-quenching and low-temperature-tempering automobile screw heat treatment equipment and a double-oil-quenching and low-temperature-tempering automobile screw heat treatment process. Comprising a quenching furnace, an oil cooling box and a moving frame, a first motor and a second motor are fixedly installed on the moving frame, a wheel disc is rotatably installed on the moving frame, an overturning frame driven by the first motor is arranged on the moving frame, two sector tooth sections and two toothless sections are alternately arranged on the wheel disc, a first lead screw is rotatably installed on the overturning frame, and a first torsional spring is arranged at the rotating joint of the first lead screw and the wheel disc; a driven gear is installed on the first lead screw, the two sector tooth sections are sequentially meshed with the driven gear, the transmission angles of the two sector tooth sections to the driven gear are different, a front-back sliding frame is connected to the first lead screw in a transmission mode, and a second lead screw is rotatably installed on the front-back sliding frame. The device has the beneficial effects that aiming at the problems of screw accumulation and high heating temperature difference caused by fixed furnace chamber and single stirring in the prior art, the quenching blind area is eliminated through the collaborative design of multi-mechanism linkage, dynamic dispersion and three-dimensional heat circulation.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of heat treatment equipment, in particular to a double-oil-quenching and low-temperature tempering automobile screw heat treatment equipment and process. BACKGROUND

[0002] The automobile screw is a core connecting piece of an automobile power system, a chassis system and a vehicle body structure, and the mechanical properties and assembly precision of the automobile screw directly determine the driving safety of the automobile. In order to meet the demand of high-strength working conditions, the heat treatment process of double-oil-quenching and low-temperature tempering is generally adopted in the industry. The first oil quenching is used to form a martensite structure of a screw base to improve the hardness, then low-temperature tempering is used to precipitate carbides and reduce internal stress, and finally the second oil quenching is used to fix the tempered martensite structure, so that the screw has high strength and low brittleness. For example, the patent No. CN108570545A discloses a heat treatment process of a bolt for an automobile. However, in the actual application, the existing heat treatment equipment and process always have multi-dimensional technical bottlenecks, so that the performance consistency and precision of the automobile screw are difficult to meet the strict requirements of high-end vehicle models. The specific problems are as follows: In the prior art, the double-oil-quenching and low-temperature tempering treatment of the automobile screw is generally in a compound dilemma of multi-dimensional uniformity loss of control and precision cleaning loss. The existing solutions are mostly optimized for a single link, and cannot break the vicious cycle among the problems. The specific performance is as follows: the existing quenching equipment mostly adopts a fixed furnace cavity and a single-direction stirring design. The screws are easy to accumulate at the bottom or side wall of the quenching container under the action of gravity, forming a stacking blind area. Taking the example of the bottom screws being shielded by the upper screws, the contact area of the bottom screws with the high-temperature airflow is only 40%-60% of that of the upper screws. The actual heating temperature difference of the screws in the same batch can reach 30-50 DEG C, and the heating time deviation is more than 20%. This difference directly leads to uneven austenitizing degree. In the high-temperature quenching process, the screw surface generates an oxide skin with a thickness of 5-10 mu m, which is easy to be embedded in the precision gaps such as the thread root and thread side, and affects the subsequent assembly of the screw. The existing oil cooling equipment relies on natural convection of oil or single circulating pump driving. The oil is easy to form a laminar flow state. The temperature gradient between the top and bottom of the oil cooling tank can reach 10-15 DEG C. When the screws cool down, the cooling rate of the area in contact with the low-temperature oil at the bottom is too fast, and the cooling rate of the area in contact with the high-temperature oil at the top lags behind. This temperature difference will generate an internal stress of 300-500 MPa in the screw. Although the second oil quenching can partially release the internal stress, the internal stress of the small-size screws of M5-M8 cannot be completely eliminated, and the cracking rate in subsequent use is high. Based on this, the application provides a double-oil-quenching and low-temperature tempering automobile screw heat treatment equipment and process to solve the problems in the background art. SUMMARY

[0003] The present application provides a double oil quenching and low-temperature tempering automobile screw heat treatment equipment and process to solve the problems of screw hardness deviation exceeding the standard, thread precision damage and internal stress cracking caused by vicious cycle of uneven heating, residual oxide scale and uneven cooling during the double oil quenching and low-temperature tempering process in the prior art.

[0004] The technical scheme for solving the above technical problems is as follows: a double oil quenching and low-temperature tempering automobile screw heat treatment equipment, comprising a quenching furnace, an oil cooling box and a moving frame, a motor one and a motor two are fixed on the moving frame and a wheel disc is rotatably installed, a turnover frame driven by the motor one is arranged on the moving frame, two fan tooth segments and two toothless segments are alternately arranged on the wheel disc, a first lead screw is rotatably installed on the turnover frame, a first torsional spring is arranged at the rotating connection position of the first lead screw, a driven gear is installed on the first lead screw, the two fan tooth segments are sequentially meshed with the driven gear, the transmission angles of the two fan tooth segments to the driven gear are different, front and rear sliding frames are drivingly connected to the first lead screw, a second lead screw is rotatably installed on the front and rear sliding frames, a second torsional spring is arranged at the rotating connection position of the second lead screw, the second lead screw is linked with the first lead screw, left and right sliding frames are drivingly connected to the second lead screw, a sealing seat is fixed on the left and right sliding frames, a rotating cylinder is arranged on the sealing seat and a toothed ring is fixed on the rotating cylinder, a conveying shaft is rotatably installed on the rotating cylinder, a helical inner blade is installed on the conveying shaft, and two symmetrical quenching cylinders and two cooling cylinders are arranged on the outer side of the rotating cylinder.

[0005] As a preferred technical scheme of the present application, an internal gear meshing with the toothed ring is installed on the quenching cylinder and the cooling cylinder, a first branch pipe is rotatably connected to the two ends of the quenching cylinder, two second branch pipes are rotatably connected to the cooling cylinder, the first branch pipe and the second branch pipe are both in communication with the rotating cylinder, a brush shaft is rotatably installed in the quenching cylinder, steel wire brush plates are uniformly arranged in the quenching cylinder, a helical brush is installed on the brush shaft, a circulating shaft is rotatably installed in the cooling cylinder, a helical outer blade is installed on the circulating shaft, and the brush shaft, the circulating shaft and the wheel disc are all driven by the motor two.

[0006] On the basis of the above technical scheme, the present application can also be improved as follows.

[0007] As a preferred technical scheme of the present application, a rack and a double-shaft driving platform installed on the rack are further included, the double-shaft driving platform is in transmission connection with the moving frame, the quenching furnace and the oil cooling box are both fixedly connected with the rack, the top end of the oil cooling box is open, a temperature probe, a refrigeration module and a blowdown valve are respectively installed on the oil cooling box, a central control unit is installed on the end face of the rack, the data end of the temperature probe and the electric control end of the refrigeration module are both in data connection with the central control unit, a furnace mouth is fixedly arranged at the front bottom end of the quenching furnace, a linear transmission module is installed on the quenching furnace, a furnace door matched with the furnace mouth is drivingly installed on the linear transmission module, and mesh holes are arrayed on the quenching cylinder, the cooling cylinder and the rotating cylinder.

[0008] As the preferred technical scheme of the present application, the axis position of the wheel disc is provided with a wheel shaft, the wheel shaft is rotatably installed on the moving frame through a bearing, the output shaft end of the motor two is in transmission connection with the wheel shaft through a first synchronous belt, both sides of the turnover frame are fixedly installed with turnover sleeve shafts, the first screw rod is arranged at the axis position of the turnover sleeve shaft, and both turnover sleeve shafts are rotatably connected with the first screw rod through bearings, a hollow rotating sleeve is rotatably arranged on one of the turnover sleeve shafts, and the hollow rotating sleeve and the other turnover sleeve shaft are rotatably connected with the moving frame, the output shaft end of the motor one is in transmission connection with a second synchronous belt, and the second synchronous belt is in transmission connection with one of the turnover sleeve shafts.

[0009] As the preferred technical scheme of the present application, the turnover frame is slidably connected with a tensioning sliding block, the side surface of the tensioning sliding block is arrayed with tensioning springs, the tensioning sliding block is rotatably installed with a tensioning wheel, the turnover frame is rotatably installed with a synchronous shaft, the synchronous shaft and the first screw rod are both installed with first bevel gears, the two first bevel gears are in orthogonal engagement, the synchronous shaft is in transmission connection with a third synchronous belt, and the tensioning wheel and the second screw rod are both in transmission connection with the third synchronous belt.

[0010] As the preferred technical scheme of the present application, the conveying shaft is rotatably connected with the left and right sliding frames, the conveying shaft and the rotating drum are both installed with second bevel gears, the sealing seat is rotatably installed with a first reversing shaft, the first reversing shaft is installed with a first intermediate bevel gear, the two second bevel gears are both in transmission connection with the first intermediate bevel gear, the two second bevel gears are arranged on the upper and lower sides of the first intermediate bevel gear, respectively, the fourth synchronous belt is in transmission connection between the hollow rotating sleeve and the wheel shaft, the turnover frame is rotatably installed with a fixed shaft, the fifth synchronous belt is in transmission connection between the fixed shaft and the hollow rotating sleeve, the hollow shaft is rotatably installed on the front and rear sliding frames, the hollow shaft is linked with the fixed shaft, and the elastic transmission belt is in transmission connection between the hollow shaft and the first reversing shaft.

[0011] As the preferred technical scheme of the present application, the hollow shaft is slidably connected with the fixed shaft through an axis hole, the cross sections of the axis hole and the fixed shaft are both regular hexagons, the elastic transmission belt is made of rubber material, and can elastically compensate the relative displacement of the first reversing shaft and the hollow shaft.

[0012] As the preferred technical scheme of the present application, the second steering shaft is rotatably installed on the sealing seat, the positive rotation sleeve is rotatably sleeved on the rotating drum, the reverse rotation sleeve is rotatably sleeved on the positive rotation sleeve, the second steering shaft is in transmission connection with the first steering shaft through the sixth synchronous belt, the second steering bevel gear is installed on the second steering shaft, the third bevel gears are installed on the positive rotation sleeve and the reverse rotation sleeve, the two third bevel gears are in transmission connection with the second steering bevel gear, the driving gear rings are installed on the positive rotation sleeve and the reverse rotation sleeve, the passive gears are installed on the brush shaft and the circulating shaft, the passive gear on the brush shaft is in meshing connection with the driving gear ring on the positive rotation sleeve, and the passive gear on the circulating shaft is in meshing connection with the driving gear ring on the reverse rotation sleeve.

[0013] As the preferred technical scheme of the present application, the end of the rotating drum and the first branch pipe are both installed with a material valve, the spiral brush comprises an inner lining spiral framework, the inner lining spiral framework is made of metal material, and the inner lining spiral framework and the steel wire brush plate are both uniformly distributed with steel wire bristles.

[0014] As the preferred technical scheme of the present application, a heat treatment process for automobile screws through double oil quenching and low-temperature tempering comprises the following steps: S1, high-temperature quenching pretreatment: opening the door of the quenching furnace, conveying the automobile screws to be treated into the quenching cylinder through the rotating drum, feeding the cooling cylinder and the quenching cylinder into the furnace cavity of the quenching furnace, shallowly sealing the furnace mouth by the sealing seat, keeping the distance between the sealing seat and the furnace mouth at 1-2 mm, then heating the quenching furnace to 850-950 DEG C, keeping the temperature for 30-60 min, and outputting the constant speed of motor two during the keeping process to drive the screws to circulate between the rotating drum and the quenching cylinder; S2, first oil quenching: transferring the quenching cylinder into the oil cooling box to cool the screws completely in the oil, controlling the oil temperature to be 20-60 DEG C, and ensuring the cooling speed to meet the process requirement of the transformation from austenite to martensite, and driving the spiral outer blade to stir the oil to ensure the uniform cooling of the screws during the cooling process; S3, low-temperature tempering: transferring the screws after the first oil quenching into the quenching furnace again, heating to 150-200 DEG C, keeping the temperature for 1-3 hours, so that the martensite precipitates carbide and transforms into tempered martensite; S4, second oil quenching: transferring the tempered screws into the cooling cylinder, and cooling them in the oil of the oil cooling box again, and driving the screws to circulate between the rotating drum and the cooling cylinder; S5, discharging and post-treatment: discharging the screws from the material valve after the cooling is completed.

[0015] The present application has the following beneficial effects: 1. In view of the problem of screw accumulation and high temperature difference caused by fixed furnace cavity and single stirring in the prior art, the present application realizes the cooperative design of multi-mechanism linkage, dynamic dispersion and three-dimensional heat circulation, eliminates the quenching blind area, and the motor-driven wheel disc rotates, the differentiated fan gear segments arranged alternately drive the first screw rod to rotate, cooperate with the first torsional spring reset, make the front and rear carriages produce forward and backward amplitude reciprocating motion, at the same time, the first screw rod drives the second screw rod through bevel gear and synchronous shaft linkage, drives the left and right carriages to realize left and right amplitude motion, and the three-dimensional composite motion is formed synchronously, which drives the quenching cylinder to dynamically displace, the inner helical blade of the conveying shaft and the helical brush of the brush shaft are reverse fed, and the screw is continuously circulated between the rotating drum and the quenching cylinder, this linkage mode of composite motion, rotation and circulation breaks the gravity accumulation, each screw can be dynamically dispersed, the heating area difference of the upper and lower screws is reduced, in addition, the composite motion can also disturb the hot air flow in the quenching furnace, so that the high-temperature air flow penetrates radially and circulates longitudinally through the array of quenching cylinder mesh holes to form a three-dimensional heat exchange, avoiding local underheating or overheating, reducing the actual heating temperature difference of the whole batch of screws, and laying a uniform foundation for the organization transformation of subsequent oil quenching and tempering, and solving the problem of hardness deviation exceeding the standard from the source.

[0016] 2. In view of the problem that the oxide skin generated by high-temperature quenching is easy to embed into the thread gap, affects the assembly precision and is difficult to remove in the prior art, the present application links the dynamic circulation of the screw with the accurate cleaning depth, realizes real-time non-damage removal of the oxide skin, during the high-temperature quenching pretreatment stage, when the screw circulates with the rotating drum and the quenching cylinder, the brush shaft in the quenching cylinder is driven to rotate by the motor, the helical brush adopts a metal lining skeleton and an evenly distributed steel wire brush structure, the rigid skeleton can penetrate into the thread root of M5, M8 small size screw, and the flexible bristles can adhere to the thread side to avoid scratching the thread precision, at the same time, the three-dimensional composite motion makes the screw constantly change the contact angle with the helical brush and the steel wire brush plate, forms a cleaning cooperation of circulating turning and multidirectional friction, completely removes the oxide skin in the gap that the traditional equipment cannot reach, compared with the prior art which only relies on subsequent polishing or non-targeted cleaning, the oxide skin removal rate of the present application is improved, and the thread size precision deviation is reduced, ensuring that the screw does not jam and fits tightly during subsequent assembly, meeting the strict requirements of high-end vehicles on the precision of connecting pieces.

[0017] 3. In view of the problems of high temperature gradient of the prior art oil cooling tank, screw sunken bottom leading to uneven cooling, high internal stress and high cracking rate, the present application builds a uniform and stable cooling environment through temperature control, movement and flow stirring triple linkage. On the one hand, the temperature probe of the oil cooling tank collects oil temperature data in real time, and the central control unit links the refrigeration module to control the oil temperature fluctuation at the set value, eliminating the temperature gradient from the source. On the other hand, the motor two drives the circulating shaft to rotate, and the spiral outer blade stirs the oil to break the laminar flow state. At the same time, the three-dimensional composite motion drives the cooling cylinder to displace in front and back and left and right in the oil cooling tank. This linkage of active stirring of the spiral outer blade and passive displacement of the cooling cylinder promotes the oil to form a penetrating flow through the cooling cylinder mesh, avoiding the screw sunken bottom. In addition, the rotating drum and the cooling cylinder form a reverse closed circulation through the second branch pipe, and the spiral inner blade and the spiral outer blade feed in reverse, pushing the screw to continuously turn in the cooling cylinder. The top surface, bottom surface and thread gap of each screw can fully contact the oil, and the cooling rate deviation is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of a double oil quenching and low temperature tempering automobile screw heat treatment equipment. Figure 2 It is Figure 1 It is a schematic diagram of the structure from another perspective. Figure 3 It is a schematic diagram of the structure of the moving frame and the turning frame. Figure 4 It is a schematic diagram of the structure of the conveying shaft and the second branch pipe. Figure 5 It is Figure 4 It is a schematic diagram of the local enlarged structure at A in the middle. Figure 6 It is a schematic diagram of the cross-sectional structure of the first branch pipe and the conveying shaft. Figure 7 It is a schematic diagram of the structure of motor one and motor two. Figure 8 It is Figure 7 It is a schematic diagram of the local enlarged structure at B in the middle. Figure 9 It is a schematic diagram of the structure of the left and right carriages and the front and rear carriages. Figure 10 It is a process flow chart of the present application.

[0019] In the drawings, the components represented by each reference numeral are listed as follows: 1, quenching furnace; 2, oil cooling tank; 3, moving frame; 4, motor one; 5, motor two; 6, wheel disc; 7, turnover frame; 8, fan tooth section; 9, first screw rod; 10, first torsion spring; 11, driven gear; 12, front and rear sliding frame; 13, second screw rod; 14, second torsion spring; 15, left and right sliding frame; 16, sealing seat; 17, rotating drum; 18, fixed gear ring; 19, conveying shaft; 20, spiral inner blade; 21, quenching cylinder; 22, cooling cylinder; 23, inner gear; 24, first branch pipe; 25, second branch pipe; 26, brush shaft; 27, steel wire brush plate; 28, circulating shaft; 29, spiral outer blade; 30, rack; 31, double-shaft driving platform; 32, temperature probe; 33, refrigeration module; 34, central control unit; 35, linear transmission module; 36, furnace door; 37, mesh; 38, turnover sleeve shaft; 39, hollow rotating sleeve; 40, tensioning sliding block; 41, tensioning spring; 42, tensioning wheel; 43, synchronous shaft; 44, first reversing shaft; 45, fixed shaft; 46, hollow shaft; 47, elastic transmission belt; 48, second reversing shaft; 49, positive rotating sleeve; 50, reverse rotating sleeve; 51, driving gear ring; 52, driven gear; 53, material valve; 54, spiral brush. DETAILED DESCRIPTION

[0020] The principles and features of the present application are described below in conjunction with the accompanying drawings, and the examples are only used to explain the present application and not to limit the scope of the present application.

[0021] The present application provides the following preferred embodiments As Figures 1-9 shown, a double oil quenching and low temperature tempering automobile screw heat treatment equipment includes a quenching furnace 1, an oil cooling tank 2 and a moving frame 3; The quenching furnace 1 adopts resistance heating, and the power is 10-20 kW; It also includes a rack 30 and a double-shaft driving platform 31 mounted thereon, the double-shaft driving platform 31 is in transmission connection with the moving frame 3, and the quenching furnace 1 and the oil cooling tank 2 are fixedly connected with the rack 30; The top end of the oil cooling tank 2 is open, and the open end is vertically upward, and the oil cooling tank 2 is respectively provided with a temperature probe 32, a refrigeration module 33 and a blowdown valve; The end surface of the rack 30 is provided with a central control unit 34, and the data end of the temperature probe 32 and the electric control end of the refrigeration module 33 are both in data connection with the central control unit 34; The positive bottom end of the quenching furnace 1 is fixedly provided with a furnace opening, the quenching furnace 1 is provided with a linear transmission module 35, and the linear transmission module 35 is drivingly provided with a furnace door 36 matched with the furnace opening; In the non-quenching state, the furnace door 36 closes the furnace opening, and the quenching furnace 1 maintains constant temperature; When quenching is needed, the furnace door 36 is moved away from the furnace mouth by the linear transmission module 35, the furnace mouth is opened, and then the cooling cylinder 22 and the quenching cylinder 21 are conveniently sent into the quenching furnace 1; The quenching furnace 1, the oil cooling tank 2 and the double-shaft driving platform 31 are integrally fixed by the rack 30, so as to ensure the stability of the overall structure of the equipment; The central control unit 34 is linked with the temperature probe 32 and the refrigeration module 33, so as to monitor and adjust the oil temperature in the oil cooling tank 2 in real time, and ensure the constant oil temperature; The blowdown valve can periodically discharge the impurities and aged oil residues deposited in the oil cooling tank 2, so as to maintain the cleanliness of the oil and avoid the adhesion of impurities on the surface of the screw to affect the precision or cause uneven cooling; The linear transmission module 35 drives the furnace door 36 to automatically open and close, replacing manual operation, which not only reduces the safety risk of manual intervention in a high-temperature environment, but also accurately controls the opening and closing speed and sealing performance of the furnace door 36, avoids the temperature loss due to the untimely opening and closing of the furnace door 36 in the constant-temperature environment of the quenching furnace 1, ensures that the screw is always in a stable high-temperature condition during quenching, and prevents heat leakage during quenching by the accurate cooperation between the furnace door 36 and the furnace mouth, thereby reducing energy consumption; A state switching station is arranged on the rack 30 at a position corresponding to the quenching furnace 1 and the oil cooling tank 2, at which the turnover frame 7 completes angle turnover and realizes the switching between the quenching state and the oil cooling state; The double-shaft driving platform 31 cooperates with the turnover frame 7, so as to accurately control the turnover range and safety of the turnover frame 7; The motor one 4 and the motor two 5 are fixed on the moving frame 3, and the wheel disc 6 is rotatably installed thereon, and the moving frame 3 is provided with the turnover frame 7 driven by the motor one 4; The wheel shaft is arranged at the axial position of the wheel disc 6, the wheel shaft is rotatably installed on the moving frame 3 through a bearing, the output shaft end of the motor two 5 is in transmission connection with the wheel shaft through a first synchronous belt, and the turnover sleeve shafts 38 are fixedly installed on the two sides of the turnover frame 7; The first screw rod 9 is arranged at the axial position of the turnover sleeve shaft 38, and the two turnover sleeve shafts 38 are rotatably connected with the first screw rod 9 through bearings, the hollow rotating sleeve 39 is rotatably arranged on one of the turnover sleeve shafts 38, and the hollow rotating sleeve 39 and the other turnover sleeve shaft 38 are rotatably connected with the moving frame 3 through bearings; The output shaft end of the motor one 4 is in transmission connection with the second synchronous belt, and the second synchronous belt is in transmission connection with one of the turnover sleeve shafts 38; The motor one 4 directly drives the turnover sleeve shaft 38 to rotate through the second synchronous belt, the transmission path is short and the power loss is small, and the rotation angle of the turnover frame 7 can be accurately controlled; The motor two 5 drives the wheel shaft and the wheel disc 6 to rotate through the first synchronous belt; the hollow rotating sleeve 39 not only realizes the rotation freedom of the turnover sleeve shaft 38, but also supports and protects the turnover sleeve shaft 38; Two fan tooth segments 8 and two toothless segments are alternately arranged on the wheel disc 6, the first screw rod 9 is rotatably arranged on the turnover frame 7, and the first torsion spring 10 is arranged at the rotating connection position of the two, the driven gear 11 is arranged on the first screw rod 9, the two fan tooth segments 8 are sequentially engaged with the driven gear 11, and the transmission angles of the two fan tooth segments 8 to the driven gear 11 are different; In a preferred embodiment, the central angles of the two fan tooth segments 8 are 100° and 130° respectively, and the central angles of the two toothless segments are both 65°; By designing the fan tooth segments 8 with different central angles, the driven gear 11 generates different rotating amounts when engaged with the fan tooth segments 8 during the rotation of the wheel disc 6, thereby driving the first screw rod 9 to rotate different strokes, and realizing the differential vibration of the front and rear carriages 12; The cooperation of the toothless segment and the first torsion spring 10 can quickly reset the first screw rod 9 after the fan tooth segment 8 disengages, thereby preparing for the next engagement, ensuring the continuity of transmission, and avoiding the interruption of the movement of the front and rear carriages 12 caused by the jamming of the first screw rod 9; The alternating distribution of the fan tooth segments 8 and the toothless segments enables the front and rear carriages 12 to finally form periodic amplitude vibration; The front and rear carriages 12 are drivingly connected with the first screw rod 9, the second screw rod 13 is rotatably arranged on the front and rear carriages 12, and the second torsion spring 14 is arranged at the rotating connection position of the two, and the second screw rod 13 is linked with the first screw rod 9; The tensioning sliding block 40 is slidingly connected with the turnover frame 7, the tensioning springs 41 are arrayed on the side surface of the tensioning sliding block 40, the tensioning wheel 42 is rotatably arranged on the tensioning sliding block 40, the synchronous shaft 43 is rotatably arranged on the turnover frame 7, the first bevel gears are arranged on the synchronous shaft 43 and the first screw rod 9, the two first bevel gears are orthogonally engaged, the third synchronous belt is drivingly connected with the synchronous shaft 43, and the tensioning wheel 42 and the second screw rod 13 are drivingly connected with the third synchronous belt; The tensioning sliding block 40 follows the forward and backward movement of the front and rear carriages 12, thereby tensioning and compensating the displacement of the front and rear carriages 12 through the third synchronous belt, and enabling the first screw rod 9 and the second screw rod 13 to maintain a linkage relationship; The first screw rod 9 drives the second screw rod 13 through the first bevel gears, the synchronous shaft 43 and the third synchronous belt, thereby enabling the front and rear carriages 12 to form a compound motion with the left and right carriages 15, and further enabling the rotating drum 17, the quenching cylinder 21 and other components to accurately change positions in a three-dimensional space; The second torsion spring 14 can play a reset buffering role when the second screw rod 13 is stopped, and can automatically reset the second screw rod 13 when it loses power, and finally, when the output rotating speed of the motor 5 is restored, the front and rear carriages 12 generate amplitude reciprocating motion in the forward and backward directions, the left and right carriages 15 generate amplitude reciprocating motion in the left and right directions, and the two motions occur synchronously; In the traditional quenching device, the screws are prone to accumulate in the quenching cylinder 21 under the action of gravity, causing the bottom layer of screws to be blocked by the upper layer and unable to contact the high-temperature gas flow in the quenching furnace 1, resulting in local underheating or local overheating. The synchronous compound motion drives the quenching cylinder 21 to make variable-amplitude reciprocating motion in three-dimensional space. The reciprocating motion in the front-back and left-right directions can push the screws to alternately roll and swing laterally, breaking the local aggregation of the screws in the radial direction. Under the synchronous action of the two, the screws are always in a dynamic dispersed state, and the surface of each screw can uniformly contact the high-temperature environment in the quenching furnace 1, avoiding hardness deviation caused by uneven heating from the source.

[0022] During the high-temperature quenching process of the screws, the surface layer is prone to form an oxide skin. If the oxide skin remains, it will affect the heat exchange efficiency during subsequent oil quenching and may adhere to the surface of the screws after cooling, reducing their assembly precision.

[0023] The spiral brush 54 in the quenching cylinder 21 is itself driven to rotate by the motor 2, and the synchronous compound motion provides multiple-direction relative motion for the screws and the spiral brush 54. On the one hand, the screws make compound motion with the quenching cylinder 21, constantly changing the contact angle with the spiral brush 54, and on the other hand, the variable-amplitude reciprocating motion allows the steel wire brush to gently and comprehensively sweep the surface of the screws, avoiding rigid friction damage to the precision of the screws and efficiently peeling off the oxide skin. When the synchronous compound motion drives the quenching cylinder 21 to alternately displace horizontally and vertically, it can disturb the hot gas flow in the quenching furnace 1. The left-right reciprocating motion allows the hot gas flow to repeatedly penetrate the mesh 37 in the radial direction of the rotating cylinder, and the front-back reciprocating motion can push the hot gas flow, forming a three-dimensional hot gas flow circulation. This circulation not only quickly replenishes the heat in the quenching cylinder 21, but also allows the hot gas flow to directly act on the surface of the screws, improving the heat exchange efficiency and ensuring that the screws maintain stable and constant temperature at the set quenching temperature, further ensuring the sufficiency of the martensitic transformation.

[0024] The oil in the oil cooling tank 2 is prone to form a temperature gradient due to heat exchange. In the traditional device, the cooling cylinder 22 is fixed and immovable, and the screws are prone to sink to the bottom and be in contact with the high-temperature oil for a long time, causing the cooling speed to lag. The synchronous compound motion drives the cooling cylinder 22 to make variable-amplitude reciprocating motion in the oil cooling tank 2. The front-back and left-right reciprocating motions can push the screws to alternately sink and float, avoiding sinking to the bottom and allowing the screws to swing laterally in the cooling cylinder 22, so that the screws constantly switch the contact position with the oil in the radial direction. Under the synchronous action of the two, the spiral cooling degree is uniform, avoiding the concentration of internal stress caused by uneven cooling and reducing the cracking rate of the cooled screws. The circulating shaft 28 in the cooling cylinder 22 is driven to rotate by the motor 5, which can in turn drive the oil to flow along the axis of the rotating cylinder, and the synchronous compound motion further amplifies the circulation effect of the oil: The left-right reciprocating motion can make the cooling cylinder 22 stir the oil in the oil cooling tank 2 transversely, breaking the laminar flow state of the oil; The front-back reciprocating motion can promote the oil to repeatedly enter and exit through the mesh holes 37 of the cooling cylinder 22, quickly taking away the heat from the surface of the screw; This synergistic mode of active push flow of the spiral outer blade 29 and passive stirring flow of the compound motion can not only ensure that the cooling speed meets the fixing requirements of the tempered martensite, but also avoid the organization embrittlement caused by too fast cooling, balancing the hardness and toughness of the screw.

[0025] The left-right slide 15 is driven on the second screw rod 13, and the sealing seat 16 is fixed on the left-right slide 15. The rotating cylinder 17 is arranged on the sealing seat 16 and fixed with the gear ring 18. The conveying shaft 19 is rotatably arranged on the rotating cylinder 17, and the spiral inner blade 20 is arranged on the conveying shaft 19. The two symmetrical quenching cylinders 21 and the two cooling cylinders 22 are arranged on the outer side of the rotating cylinder 17. The internal gear 23 meshing with the gear ring 18 is arranged on the quenching cylinder 21 and the cooling cylinder 22. The mesh holes 37 are arranged on the quenching cylinder 21, the cooling cylinder 22 and the rotating cylinder 17; The quenching cylinder 21 and the cooling cylinder 22 are made of metal material. The mesh hole 37 diameter and the mesh hole 37 density of the quenching cylinder 21, the cooling cylinder 22 and the rotating cylinder 17 can be customized according to the cooling and quenching requirements; The meshing transmission of the gear ring 18 and the internal gear 23 can drive the quenching cylinder 21 and the cooling cylinder 22 to rotate synchronously when the rotating cylinder 17 moves, without the need for additional driving components, which simplifies the equipment structure and reduces the energy consumption. At the same time, the rotation can drive the internal screw to turn, avoiding the accumulation of the screw, ensuring that each screw can fully contact with the high-temperature environment of the quenching furnace 1 or the oil of the oil cooling tank 2, and improving the uniformity of quenching and cooling; The array mesh hole 37 provides a channel for heat transfer and oil flow. During quenching, the high temperature is quickly transferred to the inside of the quenching cylinder 21 through the mesh hole 37, ensuring that the screw quickly reaches the quenching temperature; During cooling, the oil enters the cooling cylinder 22 through the mesh hole 37, accelerates the heat dissipation of the screw, and improves the cooling efficiency; In addition, the mesh hole 37 diameter and density can be customized according to the screw specifications. When processing small-sized screws, small-diameter mesh holes 37 are used to prevent material leakage. When processing large-sized screws, the diameter is increased to improve the heat transfer efficiency and enhance the adaptability of the equipment to different types of automobile screws; Both ends of the quenching cylinder 21 are rotationally communicated with first branch pipes 24, and the cooling cylinder 22 is rotationally communicated with two second branch pipes 25, the first branch pipes 24 and the second branch pipes 25 are communicated with the rotating cylinder 17, the quenching cylinder 21 is rotationally installed with a brush shaft 26, and the quenching cylinder 21 is uniformly distributed with steel wire brush plates 27, the brush shaft 26 is installed with a spiral brush 54, the cooling cylinder 22 is rotationally installed with a circulating shaft 28, the circulating shaft 28 is installed with a spiral outer blade 29, the circulating shaft 28, the brush shaft 26 and the wheel disc 6 are driven by the second motor 5, and the rotating directions of the circulating shaft 28 and the brush shaft 26 are opposite.

[0026] The ends of the rotating cylinder 17 and one first branch pipe 24 are both installed with material valves 53, the spiral brush 54 comprises an inner lining spiral framework, the inner lining spiral framework is made of metal material, and the inner lining spiral framework and the steel wire brush plate 27 are both uniformly distributed with steel wire bristles; The steel wire bristles are made of 304 stainless steel wires with a diameter of 0.1 mm and a hardness of HV200-250, so as to avoid damaging the thread precision; When feeding, the screws to be heat treated are sent in through the material valves 53 on the first branch pipes 24, and when discharging, the material is discharged through the material valves 53 on the rotating cylinder 17 in the state that the rotating cylinder 17 is vertically downward; In the quenching state, the ends of the material valves 53 of the rotating cylinder 17 are vertically upward, when the rotating cylinder 17 rotates, the spiral inner blade 20 transports the material to the side of the material valve 53, and in this state, since the inclined directions of the first branch pipes 24 and the second branch pipes 25 and the material guiding directions are different, at this time, the second branch pipes 25 do not produce material flow under the action of the inclination, and the first branch pipes 24 guide the material; Specifically, in this state, the spiral inner blade 20 feeds upward, the spiral brush 54 feeds downward, and at the same time, due to the communication of the two first branch pipes 24, during quenching, the screws to be quenched circulate and flow back in the rotating cylinder 17 and the quenching cylinder 21, and in the process of circulating and flowing back, the spiral brush 54 and the steel wire brush plate 27 process the screws in the quenching state to remove the high-temperature oxide scale on the surface of the screws in real time, so as to avoid the influence of the oxide scale on the screw precision and subsequent assembly performance; This dynamic circulation enables each screw to periodically pass through the high-temperature area of the quenching cylinder 21, there is no quenching blind area, the heating time and heating temperature deviation of the whole batch of screws are controlled within the preset range, the austenitizing degree is highly consistent, and the problem of uneven hardness in traditional quenching is solved; During high-temperature quenching, the oxide scale is easily embedded in the thread tooth side, tooth bottom and other gaps, and the traditional cleaning method is difficult to enter the gap, resulting in residual oxide scale; The residual oxide scale not only reduces the assembly precision of the screw, but also hinders heat exchange during subsequent oil quenching, affecting the cooling effect; In the application, the upward and downward circulation and flow back of the screw and the active cleaning of the spiral brush 54 are coordinated; The screw constantly changes its posture with the cyclical movement, while the spiral brush 54 combines rigidity and flexibility. The rigid frame ensures that the bristles can penetrate the gaps and reach deep into the thread. Flexible bristles can conform to the sides of the thread and avoid scratching the thread precision; At the same time, the repeated circulation ensures that the oxide scale in the gaps is completely removed; In the cooling state, the material valve 53 end of the rotating drum 17 is set vertically downward. When the rotating drum 17 rotates, the inner spiral blade 20 conveys material towards the side of the material valve 53. In this state, since the inclination direction of the first branch pipe 24 and the material guiding direction of the second branch pipe 25 are different, the first branch pipe 24 does not produce material flow under the action of the inclination, while the second branch pipe 25 guides the material. The conveying direction of the spiral conveying blade is upward. In this state, the screw to be cooled circulates back and forth in the rotating drum 17 and the cooling drum 22. In traditional oil cooling equipment, screws tend to accumulate at the bottom of the cooling cylinder 22 due to gravity, resulting in the bottom screws only having their contact surfaces in contact with the oil, while the top screws cool down later, leading to a large difference in cooling rates and thus generating internal stress, which can easily cause deformation and cracking during subsequent use. In this invention, the combination of the vertical downward end of the material valve 53 of the rotating drum 17, the upward feeding of the spiral inner blade 20, and the directional guiding of the material by the second branch pipe 25, enables the screw to form a reverse closed loop within the rotating drum 17 and the cooling cylinder 22. After the screw enters the cooling cylinder 22 from the rotating drum 17 through the second branch pipe 25, it returns to the rotating drum 17 under the push of the outer spiral blade 29, and there is no material accumulation during the circulation process; Furthermore, the bidirectional flipping of the inner spiral blade 20 and the outer spiral blade 29 allows the screw to continuously rotate in the cycle, ensuring that the top, bottom, side, and thread gaps of the screw can fully contact the oil. The cooling rate deviation is controlled within the preset value, solving the problem of internal stress cracking caused by uneven cooling. Meanwhile, in traditional equipment, the oil only flows in a fixed direction, resulting in insufficient heat exchange with the screw, slow cooling rate, and incomplete martensitic structure. In this invention, the screw's upward and downward circulating flow works in synergy with the mesh structure 37; The cooling cylinder 22 and the rotating cylinder 17 are both arrayed with mesh holes 37. During the screw circulation process, the oil can penetrate through the mesh holes 37 to contact the screw surface. Meanwhile, the tumbling and disturbance of the oil by the inner spiral blade 20 and the outer spiral blade 29 creates local turbulence, which improves the heat exchange efficiency, stabilizes the cooling rate, and makes the martensitic structure more complete. The conveying shaft 19 is rotationally connected with the left and right carriages 15, the conveying shaft 19 and the rotating drum 17 are both provided with second bevel gears, the sealing seat 16 is rotationally provided with a first reversing shaft 44, the first reversing shaft 44 is provided with a first intermediate bevel gear, the two second bevel gears are both in transmission connection with the first intermediate bevel gear, and the two second bevel gears are respectively arranged on the upper and lower sides of the first intermediate bevel gear; The hollow rotating sleeve 39 is in transmission connection with the wheel shaft through a fourth synchronous belt, the turnover frame 7 is rotationally provided with a fixed shaft 45, the fixed shaft 45 is in transmission connection with the hollow rotating sleeve 39 through a fifth synchronous belt, the front and rear carriages 12 are rotationally provided with a hollow shaft 46, the hollow shaft 46 is linked with the fixed shaft 45, the hollow shaft 46 is provided with a shaft hole in sliding connection with the fixed shaft 45, and the cross sections of the shaft hole and the fixed shaft 45 are both regular hexagons. The hollow shaft 46 is in transmission connection with the first reversing shaft 44 through an elastic transmission belt 47.

[0027] The elastic transmission belt 47 is made of rubber and can elastically compensate the relative displacement of the first reversing shaft 44 and the hollow shaft 46.

[0028] In a preferred embodiment, the elastic transmission belt 47 can be axially stretched by 10-20 mm to compensate the displacement; Through the linkage of the fourth synchronous belt, the fifth synchronous belt, the bevel gears and other components, the power of the motor two 5 is sequentially transmitted to the conveying shaft 19 and the rotating drum 17, single power source drives multiple component movements are realized, the power system is simplified, the manufacturing cost is reduced, meanwhile, the transmission path is efficient, the rotation speeds of the conveying shaft 19 and the rotating drum 17 are synchronized, the feeding speed of the screw inner blade 20 is matched with the rotation speed of the rotating drum 17, the screw accumulation or the too fast conveying to cause insufficient processing is avoided; The regular hexagonal shaft hole of the hollow shaft 46 and the fixed shaft 45 is matched, which can stably transmit the power and allow the hollow shaft 46 to slide along the fixed shaft 45 with the front and rear carriages 12, meets the power transmission requirement in displacement and avoids the transmission interruption; The sealing seat 16 is rotationally provided with a second reversing shaft 48, the rotating drum 17 is rotationally provided with a positive rotating sleeve 49, the positive rotating sleeve 49 is rotationally provided with a reverse rotating sleeve 50, the second reversing shaft 48 is in transmission connection with the first reversing shaft through a sixth synchronous belt, the second reversing shaft 48 is provided with a second reversing bevel gear, the positive rotating sleeve 49 and the reverse rotating sleeve 50 are both provided with third bevel gears, the two third bevel gears are both in transmission connection with the second reversing bevel gear, the positive rotating sleeve 49 and the reverse rotating sleeve 50 are both provided with driving gear rings 51, the brush shaft 26 and the circulating shaft 28 are both provided with driven gears 52, the driven gear 52 on the brush shaft 26 is in meshing connection with the driving gear ring 51 on the positive rotating sleeve 49, and the driven gear 52 on the circulating shaft 28 is in meshing connection with the driving gear ring 51 on the reverse rotating sleeve 50.

[0029] The single power source drives the brush shaft 26 and the circulating shaft 28 to rotate in opposite directions through the cooperation of the second steering shaft 48, the second steering bevel gear, the positive rotation sleeve 49, and the reverse rotation sleeve 50, without the need for an additional reverse motor, simplifying the device structure and reducing energy consumption, while ensuring that the rotation directions of the brush shaft 26 and the circulating shaft 28 are exactly opposite, adapting to the movement needs of different processing stages of the screw, ensuring sufficient circulation of the screw during quenching and uniform turning during cooling; The positive rotation sleeve 49 and the reverse rotation sleeve 50 are sleeved on the rotating drum 17, which is compact in structure, saves space, and can move synchronously with the rotating drum 17 while rotating independently in the opposite direction, avoiding interference with the movement of the rotating drum 17; The meshing transmission of the driving gear ring 51 and the driven gear 52 has a stable transmission ratio, ensuring that the rotation speeds of the brush shaft 26 and the circulating shaft 28 are constant, avoiding uneven screw conveying or turning due to rotation speed fluctuations; The sixth synchronous belt ensures that the first steering shaft and the second steering shaft 48 rotate synchronously, providing a stable rotation speed basis for bevel gear transmission, further ensuring the coordination of the rotation speeds of the brush shaft 26 and the circulating shaft 28, and improving the consistency of screw processing effect.

[0030] As shown in Figure 10 An automobile screw heat treatment process for double oil quenching and low-temperature tempering includes the following steps: S1, high-temperature quenching pretreatment: open the furnace door 36 of the quenching furnace 1, convey the automobile screws to be processed into the quenching cylinder 21 through the rotating drum 17, and send the cooling cylinder 22 and the quenching cylinder 21 into the furnace cavity of the quenching furnace 1. The sealing seat 16 performs a shallow seal on the furnace opening, the distance between the sealing seat 16 and the furnace opening is kept at 1.5 mm, then the quenching furnace 1 is heated to 900℃, the holding time is 45 min, and the motor 2 outputs a constant speed during the holding process to drive the screws to circulate between the rotating drum 17 and the quenching cylinder 21; S2, first oil quenching: move the quenching cylinder 21 into the oil cooling tank 2 to cool the screws completely immersed in the oil, control the oil temperature at 20℃, and ensure that the cooling speed meets the process requirements of the transformation of austenite to martensite. During the cooling process, the circulating shaft 28 drives the spiral outer blade 29 to stir the oil to ensure uniform cooling of the screws; S3, low-temperature tempering: move the screws after the first oil quenching back into the quenching furnace 1, heat to 180℃, and hold for 2 hours to make the martensite precipitate carbides and transform into tempered martensite; S4, second oil quenching: move the tempered screws into the cooling cylinder 22 and immerse them again in the oil in the oil cooling tank 2 to cool them while driving them to circulate between the rotating drum 17 and the cooling cylinder 22; S5, discharging and post-processing: after cooling is completed, the screws are discharged from the material valve 53.

[0031] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A heat treatment equipment for automobile screw of double oil quenching and low temperature tempering, comprising a quenching furnace (1), an oil cooling box (2) and a moving frame (3), characterized in that, The moving frame (3) is provided with a motor I (4) and a motor II (5) and a rotatingly installed wheel disc (6), the moving frame (3) is provided with a turnover frame (7) driven by the motor I (4), the wheel disc (6) is alternately provided with two fan tooth segments (8) and two toothless segments, the turnover frame (7) is rotatingly installed with a first lead screw (9), and the rotating connection part is provided with a first torsional spring (10), the first lead screw (9) is installed with a driven gear (11), the two fan tooth segments (8) are in turn engaged with the driven gear (11), and the transmission angles of the two fan tooth segments (8) to the driven gear (11) are different, the first lead screw (9) is drivingly connected with front and rear sliding frames (12), the front and rear sliding frames (12) are rotatingly installed with a second lead screw (13), and the rotating connection part is provided with a second torsional spring (14), the second lead screw (13) is linked with the first lead screw (9), the second lead screw (13) is drivingly installed with left and right sliding frames (15), the left and right sliding frames (15) are fixedly provided with a sealing seat (16), the sealing seat (16) is provided with a rotating cylinder (17) and fixedly provided with a toothed ring (18), the rotating cylinder (17) is rotatingly installed with a conveying shaft (19), the conveying shaft (19) is installed with a spiral inner blade (20), the outer side of the rotating cylinder (17) is provided with two symmetrical quenching cylinders (21) and two cooling cylinders (22).

2. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 1, wherein The quenching cylinder (21) and the cooling cylinder (22) are both installed with an internal gear (23) engaged with the toothed ring (18), both ends of the quenching cylinder (21) are rotatingly communicated with a first branch pipe (24), the cooling cylinder (22) is rotatingly communicated with two second branch pipes (25), the first branch pipe (24) and the second branch pipe (25) are both communicated with the rotating cylinder (17), the quenching cylinder (21) is rotatingly installed with a brush shaft (26), and steel wire brush plates (27) are uniformly distributed in the quenching cylinder (21), the brush shaft (26) is installed with a spiral brush (54), the cooling cylinder (22) is rotatingly installed with a circulating shaft (28), the circulating shaft (28) is installed with a spiral outer blade (29), the circulating shaft (28), the brush shaft (26) and the wheel disc (6) are all driven by the motor II (5).

3. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 2, wherein It also includes a rack (30) and a double-shaft driving platform (31) installed thereon, the double-shaft driving platform (31) is drivingly connected with the moving frame (3), the quenching furnace (1) and the oil cooling tank (2) are both fixedly connected with the rack (30), the top end of the oil cooling tank (2) is open, the oil cooling tank (2) is respectively installed with a temperature probe (32), a refrigeration module (33) and a blowdown valve, the end face of the rack (30) is installed with a central control unit (34), the data end of the temperature probe (32) and the electric control end of the refrigeration module (33) are both data-connected with the central control unit (34), the positive bottom end of the quenching furnace (1) is fixedly provided with a furnace mouth, the quenching furnace (1) is installed with a linear transmission module (35), the linear transmission module (35) is drivingly installed with a furnace door (36) matched with the furnace mouth, the quenching cylinder (21), the cooling cylinder (22) and the rotating cylinder (17) are all arrayed with mesh holes (37).

4. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 2, wherein The axis position of the wheel disc (6) is provided with an axle, the axle is rotatably installed on the moving frame (3) through a bearing, the output shaft end of the motor two (5) is in transmission connection with the axle through a first synchronous belt, both sides of the turnover frame (7) are fixedly provided with turnover sleeve shafts (38), the first screw rod (9) is arranged at the axis position of the turnover sleeve shaft (38), and both turnover sleeve shafts (38) are rotatably connected with the first screw rod (9) through bearings, a hollow rotating sleeve (39) is rotatably arranged on one of the turnover sleeve shafts (38), and the hollow rotating sleeve (39) and the other turnover sleeve shaft (38) are rotatably connected with the moving frame (3), and the output shaft end of the motor one (4) is in transmission connection with a second synchronous belt, and the second synchronous belt is in transmission connection with one of the turnover sleeve shafts (38).

5. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 4, wherein The turnover frame (7) is slidably connected with a tensioning sliding block (40), the side surface of the tensioning sliding block (40) is arrayed with tensioning springs (41), the tensioning sliding block (40) is rotatably provided with a tensioning wheel (42), the turnover frame (7) is rotatably provided with a synchronous shaft (43), the synchronous shaft (43) and the first screw rod (9) are both provided with first bevel gears, the two first bevel gears are in orthogonal engagement, the synchronous shaft (43) is in transmission connection with a third synchronous belt, and the tensioning wheel (42) and the second screw rod (13) are both in transmission connection with the third synchronous belt.

6. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 5, wherein The conveying shaft (19) is rotatably connected with the left and right sliding frames (15), the conveying shaft (19) and the rotating drum (17) are both provided with second bevel gears, the sealing seat (16) is rotatably provided with a first reversing shaft (44), the first reversing shaft (44) is provided with a first intermediate bevel gear, the two second bevel gears are both in transmission connection with the first intermediate bevel gear, and the two second bevel gears are arranged on the upper and lower sides of the first intermediate bevel gear, the fourth synchronous belt is in transmission connection between the hollow rotating sleeve (39) and the axle, the turnover frame (7) is rotatably provided with a fixed shaft (45), the fifth synchronous belt is in transmission connection between the fixed shaft (45) and the hollow rotating sleeve (39), the hollow shaft (46) is rotatably arranged on the front and rear sliding frames (12), the hollow shaft (46) is linked with the fixed shaft (45), and the elastic transmission belt (47) is in transmission connection between the hollow shaft (46) and the first reversing shaft (44).

7. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 6, wherein The hollow shaft (46) is rotatably arranged on the front and rear sliding frames (12), the hollow shaft (46) is linked with the fixed shaft (45), and the elastic transmission belt (47) is in transmission connection between the hollow shaft (46) and the first reversing shaft (44). The hollow shaft (46) is rotatably arranged on the front and rear sliding frames (12), the hollow shaft (46) is linked with the fixed shaft (45), and the elastic transmission belt (47) is in transmission connection between the hollow shaft (46) and the first reversing shaft (44).

8. A heat treatment apparatus for a double oil quenching and low temperature tempering of an automobile screw according to claim 7, wherein A second steering shaft (48) is rotatably installed on the sealing seat (16), a positive rotation sleeve (49) is rotatably sleeved on the rotating drum (17), a reverse rotation sleeve (50) is rotatably sleeved on the positive rotation sleeve (49), the second steering shaft (48) is in transmission connection with the first steering shaft through the sixth synchronous belt, a second steering bevel gear is installed on the second steering shaft (48), a third bevel gear is installed on the positive rotation sleeve (49) and the reverse rotation sleeve (50), the two third bevel gears are in transmission connection with the second steering bevel gear, a driving gear ring (51) is installed on the positive rotation sleeve (49) and the reverse rotation sleeve (50), a driven gear (52) is installed on the brush shaft (26) and the circulating shaft (28), the driven gear (52) on the brush shaft (26) is in meshing connection with the driving gear ring (51) on the positive rotation sleeve (49), and the driven gear (52) on the circulating shaft (28) is in meshing connection with the driving gear ring (51) on the reverse rotation sleeve (50).

9. A heat treatment apparatus for dual oil quenching and low temperature tempering of automotive screws as claimed in claim 2 wherein, A material valve (53) is installed on the end of the rotating drum (17) and one of the first branch pipes (24), the spiral brush (54) comprises an inner lining spiral framework, the inner lining spiral framework is made of metal, and steel wire bristles are uniformly distributed on the inner lining spiral framework and the steel wire brush plate (27).

10. The process according to any one of claims 1-9, characterized in that, The method comprises the following steps: S1, high-temperature quenching pretreatment: opening the furnace door (36) of the quenching furnace (1), conveying the automobile screw to be treated into the quenching cylinder (21) through the rotating drum (17), feeding the cooling cylinder (22) and the quenching cylinder (21) into the furnace cavity of the quenching furnace (1), shallowly sealing the furnace opening by the sealing seat (16), keeping the distance between the sealing seat (16) and the furnace opening at 1-2 mm, then heating the quenching furnace (1) to 850-950 ℃, and keeping the temperature for 30-60 min, during the keeping process, the motor two (5) outputs constant speed, and drives the screw to circulate between the rotating drum (17) and the quenching cylinder (21); S2, first oil quenching: moving the quenching cylinder (21) into the oil cooling box (2), so that the screw is completely immersed in the oil for cooling, controlling the oil temperature to be 20-60 ℃, and the cooling speed meets the process requirement of the transformation of austenite into martensite, during the cooling process, the spiral outer blade (29) is driven by the circulating shaft (28) to stir the oil, so that the screw is uniformly cooled; S3, low-temperature tempering: moving the screw after the first oil quenching into the quenching furnace (1) again, heating to 150-200 ℃, and keeping the temperature for 1-3 hours, so that the martensite precipitates carbide and is transformed into tempered martensite; S4, second oil quenching: moving the tempered screw into the cooling cylinder (22), and immersing the screw into the oil in the oil cooling box (2) again for cooling, and driving the screw to circulate between the rotating drum (17) and the cooling cylinder (22); S5, discharging and post-treatment: after the cooling is completed, the screw is discharged from the material valve (53).

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