Rack rotary forging press and rack machining method

Abstract

The invention discloses a rack rotary forging press and a rack machining method.The rack rotary forging press comprises an upper die, a lower die, a swing part and a pushing part, forming teeth are arranged on the bottom face of the upper die, a containing groove is formed in the upper surface of the lower die, the swing part drives the upper die to swing around the forming axis, and the pushing part is pushed to drive the lower die to vertically move; a rack blank is arranged between the upper die and the lower die, the rack blank is arranged and fixed in the containing groove, and the forming teeth make contact with the rack blank and are subjected to rotary forging; compared with a cutting machining forming mode in the prior art, the forming method has the advantages that racks with higher tooth hardness can be machined, meanwhile, variable-pitch tooth types can be produced in batches, the applicability is higher, and the equipment pressure needed for machining the same racks is lower.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive parts production, and particularly relates to a rack rotary forging machine and a rack processing method. Background Art

[0002] The automotive steering system is a mechanism used to change or maintain the driving direction of an automobile, ensuring that the automobile can steer according to the driver's will. The steering gear assembly is an important part of the automotive steering system. Common steering gears include rack and pinion type, worm and crank pin type, and recirculating ball type. The rack and pinion steering gear is widely used in automobiles due to its simple and compact structure and high transmission efficiency. Since the steering gear is used frequently during vehicle driving and the working conditions are complex, abnormal noises are likely to occur. Among them, the abnormal noise generated during the meshing process of the steering gear and the steering rack is particularly obvious. When the vibration frequency during the meshing of the steering gear and the steering rack is close to or the same as the natural frequency of the steering gear assembly itself, resonance will occur and abnormal noises will be emitted. Therefore, the processing quality of the steering rack directly affects the comfort of users and the overall vehicle quality.

[0003] The toothed part of the existing automotive steering rack is generally produced by machining. The conventional machining process includes broaching a solid round bar. The rack produced by machining generally can only have teeth with a constant pitch, that is, straight teeth or helical teeth with an unchanged modulus for mass production. At the same time, the hardness of the rack during processing also needs to be relatively low for better processing, and the production applicability is poor.

[0004] In view of the above-mentioned defects, the creator of the present invention finally obtained the present invention through long-term research and practice. Summary of the Invention

[0005] To solve the above technical defects, the technical solution adopted by the present invention is to provide a rack rotary forging machine, which includes an upper die, a lower die, a swinging part, and a pushing part. A forming tooth is provided on the bottom surface of the upper die, a placement groove is provided on the upper surface of the lower die, the swinging part drives the upper die to swing around the forming axis, the pushing part drives the lower die to move vertically, a rack blank is arranged between the upper die and the lower die, the rack blank is fixed in the placement groove, and the forming tooth contacts and rotary forges the rack blank.

[0006] Preferably, the pushing part includes a lower slider and an oil cylinder. The telescopic rod of the oil cylinder is fixedly connected to the lower slider, the lower die is fixedly arranged on the upper surface of the lower slider, and the oil cylinder adjusts and controls the vertical movement of the lower slider.

[0007] Preferably, the swinging part includes a swinging assembly, a swinging head and an upper positioning plate. The swinging assembly is fixedly connected to the swinging head. The swinging head is arranged on the upper positioning plate. The upper die is fixedly arranged on the swinging head. The upper positioning plate is fixedly arranged. A swinging groove is arranged on the upper positioning plate. The swinging head is arranged in the swinging groove. The swinging head is provided with a swinging surface. The groove surface of the swinging groove and the swinging surface are arc surfaces arranged in cooperation, and the radius of the groove surface of the swinging groove is the same as the radius of the swinging surface. The groove surface of the swinging groove and the swinging surface slide relative to each other.

[0008] Preferably, the forming axis is parallel to the axis of the rack blank, and during rotary forging forming, the forming axis and the axis of the rack blank are coaxially arranged.

[0009] Preferably, the swinging assembly includes a connecting plate, a connecting shaft, a connecting rod, an eccentric shaft and a rotating wheel. The eccentric shaft is eccentrically arranged on the rotating wheel. The axis of the eccentric shaft, the axis of the connecting shaft and the axis of the rotating wheel are parallel. The two ends of the connecting rod are respectively rotatably connected to the connecting shaft and the eccentric shaft. The connecting shaft is fixedly connected to one end of the connecting plate. The other end of the connecting plate is fixedly connected to the swinging head.

[0010] Preferably, the connecting plate and the swinging head are fixed by a positioning pin. The positioning pin is a straight rod with a polygonal cross-section. Positioning holes corresponding to the positioning pin are arranged on both the connecting plate and the swinging head. The positioning pin is simultaneously arranged in the positioning holes of the connecting plate and the swinging head.

[0011] Preferably, a method for processing a rack, using the rack rotary forging machine, includes the steps:

[0012] S1, blanking;

[0013] Obtain a cylindrical blank through blanking;

[0014] S2, pre-spraying and heating;

[0015] Heat the cylindrical blank and pre-spray graphite;

[0016] S3, rack rotary forging;

[0017] Put the pre-sprayed cylindrical blank into the lower die. The pushing part drives the lower die to move upward until the cylindrical blank is in pressure contact with the upper die. The swinging head swings reciprocally to perform rotary forging on the cylindrical blank to extrude the tooth surface shape to obtain the final product.

[0018] Preferably, in the step S2, the cylindrical blank is heated to 160°C to 180°C.

[0019] Preferably, in the step S3, the swing amplitude of the swing head is ±3° with the vertical line as the center line and the forming axis as the center of the circle.

[0020] Preferably, the process of the step S3 is as follows: the oil cylinder moves upward to drive the lower slider to move upward. Place the cylindrical blank in the lower die. When the lower die and the upper die are closed, the eccentric shaft rotates eccentrically and is transmitted to the connecting shaft through the connecting rod. The connecting plate is fixed to the swing head through the positioning pin to drive the upper die to swing reciprocally to achieve the purpose of rotary forging.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention realizes the closing of the upper die and the lower die by setting the pushing part that applies pressure by moving up and down, and at the same time drives the upper die to swing through the swinging part, so as to realize the rotary forging forming operation of the upper die on the rack blank. Compared with the cutting processing forming method in the prior art, the present invention can process racks with higher tooth hardness and can also mass-produce tooth profiles with variable pitches, with stronger applicability and lower equipment pressure required for processing the same racks; 2. The rack processing method of the present invention solves the problem of difficult processing of quenched and tempered parts through cold forging rotary forging. Utilizing the principle of rotary forging, the teeth are hardened and the service life of the rack is improved, which is suitable for large-scale automated production. Description of the Drawings

[0022] Figure 1 is a structural schematic diagram of the rack rotary forging machine;

[0023] Figure 2 is a flow chart of the rack processing method.

[0024] The numbers in the figure represent:

[0025] 1 - upper die; 2 - lower die; 3 - lower slider; 4 - oil cylinder; 5 - oil pipe; 6 - hydraulic workstation; 7 - swing head; 8 - upper positioning plate; 9 - connecting plate; 10 - connecting shaft; 11 - connecting rod; 12 - eccentric shaft; 13 - rotating wheel; 14 - motor; 15 - transmission belt; 16 - positioning pin. Detailed Embodiments

[0026] The following further elaborates on the technical features and advantages of the present invention in conjunction with the accompanying drawings.

[0027] Embodiment 1

[0028] As Figure 1 shown, Figure 1It is a schematic structural diagram of the rack rotary forging machine. The rack rotary forging machine of the present invention includes an upper die 1, a lower die 2, a swinging part and a pushing part. A forming tooth is provided on the bottom surface of the upper die 1, and a placement groove is provided on the upper surface of the lower die 2. The swinging part drives the upper die 1 to swing around the forming axis, and the pushing part drives the lower die 2 to move vertically. The rack blank is arranged between the upper die 1 and the lower die 2. The pushing part drives the rack blank placed in the placement groove to move upward until it is extruded and deformed by the forming tooth. Then, the swinging part drives the upper die 1 to swing, so that the forming tooth forms a complete tooth profile on the rack blank, thus completing the operation of rotary forging tooth forming.

[0029] In the present invention, the pushing part that applies pressure by moving up and down is set to realize the die closing of the upper die 1 and the lower die 2. At the same time, the swinging part drives the upper die 1 to swing, so as to realize the rotary forging forming operation of the upper die 1 on the rack blank. Compared with the cutting processing forming method in the prior art, the present invention can process racks with higher tooth hardness and can also mass-produce variable pitch tooth profiles, with stronger applicability and lower equipment pressure required for processing the same racks.

[0030] Preferably, the pushing part includes a lower slider 3, an oil cylinder 4, an oil pipe 5 and a hydraulic workstation 6. The hydraulic workstation 6 is connected to the oil cylinder 4 through the oil pipe 5. The telescopic rod of the oil cylinder 4 is fixedly connected to the lower slider 3. The lower die 2 is fixedly arranged on the upper surface of the lower slider 3. The vertical movement of the lower slider 3 can be adjusted and controlled by the oil cylinder 4 to realize the die closing operation of the lower die 2 moving upward.

[0031] The swinging part includes a swinging assembly, a swing head 7 and an upper positioning plate 8. The swinging assembly is fixedly connected to the swing head 7. The swing head 7 is arranged on the upper positioning plate 8. The upper die 1 is fixedly arranged on the swing head 7. The upper positioning plate 8 is fixedly arranged. A swinging groove is provided on the upper positioning plate 8. The swing head 7 is provided with a swinging surface. The groove surface of the swinging groove and the swinging surface are arc surfaces that are matched with each other, and the radius of the groove surface of the swinging groove is the same as the radius of the swinging surface. Thus, the swinging operation of the swing head 7 is realized by the swinging of the swinging surface on the groove surface of the swinging groove.

[0032] Generally, the axis of the swinging surface is the forming axis.

[0033] Preferably, the forming axis is parallel to the axis of the rack blank, and during rotary forging forming, the forming axis and the axis of the rack blank are coaxially arranged, so as to ensure the formation of a tooth profile structure with high precision and integrity during rotary forging.

[0034] Preferably, the swing assembly includes a connecting plate 9, a connecting shaft 10, a connecting rod 11, an eccentric shaft 12 and a rotating wheel 13. The eccentric shaft 12 is eccentrically arranged on the rotating wheel 13. The axis of the eccentric shaft 12, the axis of the connecting shaft 10 and the axis of the rotating wheel 13 are arranged in parallel. The two ends of the connecting rod 11 are respectively rotatably connected to the connecting shaft 10 and the eccentric shaft 12. The connecting shaft 10 is fixedly connected to one end of the connecting plate 9, and the other end of the connecting plate 9 is fixedly connected to the swing head 7, so as to realize the reciprocating swing of the swing head 7 through the rotation of the rotating wheel 13.

[0035] Generally, the rotating wheel 13 is driven to rotate by a motor 14 through a transmission belt 15. The connecting plate 9 and the swing head 7 are fixed by a positioning pin 16. The positioning pin 16 is generally a straight rod with a polygonal cross-section. Positioning holes corresponding to the positioning pin 16 are provided on both the connecting plate 9 and the swing head 7. By inserting the positioning pin 16 into the positioning holes at the same time, the fixed connection between the connecting plate 9 and the swing head 7 is realized.

[0036] Embodiment 2

[0037] As Figure 2 shown, Figure 2 is a flowchart of the rack processing method. The rack processing method of the present invention uses the rack rotary forging machine, including the steps:

[0038] S1, blanking;

[0039] Use a circular saw to saw off the blank to obtain a cylindrical blank with appropriate cross-sectional dimensions;

[0040] S2, pre-spraying and heating;

[0041] Heat the cylindrical blank to 160°C - 180°C and pre-spray graphite;

[0042] S3, cold rotary forging of the rack;

[0043] Put the pre-sprayed cylindrical blank into the lower die 2. The pushing part drives the lower die 2 to move upward until the cylindrical blank is in pressure contact with the upper die 1. The swing head 7 swings reciprocally to perform rotary forging on the cylindrical blank to extrude the tooth surface shape to obtain the final product.

[0044] Among them, in the step S2, the pre-sprayed graphite uses a pre-spraying liquid. The graphite model in the pre-spraying liquid is Fuchs FC-331DX, and the ratio of the pre-spraying liquid is graphite: water = 1:3.

[0045] Preferably, in the step S3, the swing amplitude of the swing head 7 is ±3° with the vertical line as the center line and the forming axis as the center of the circle, so as to ensure a better rack product with tooth shape. At the same time, a 500T rotary forging machine can be used to apply pressure for the final tooth shape rotary forging during cold rotary forging.

[0046] Preferably, the specific process of the step S3 is as follows: Start the hydraulic station to supply oil and output it through the oil pipe 5 to push the lower oil cylinder 4 to move upward, driving the lower slider 3 to move upward. Place the cylindrical blank in the lower die 2. When the lower die 2 and the upper die 1 are closed, the motor 14 is started, and the eccentric shaft 12 is driven to rotate eccentrically through the transmission belt 15, and then transmitted to the connecting shaft 10 through the connecting rod 11. The connecting plate 9 is fixed to the swing head 7 through the positioning pin 16 to drive the upper die 1 to swing reciprocally to achieve the purpose of rotary forging.

[0047] Through the lubrication treatment in step S2, a film lubrication without harmful substances is formed, reducing the environmental pressure and the manufacturing cost of the rack, and effectively reducing the equipment pressure required for rack rotary forging.

[0048] The rack rotary forging adopted in the present invention is cold forging rotary forging extrusion, which can form the shape of the blank with HB160 - HB165 into a part at one time, realizing forming without removing materials, improving the material utilization rate. Cooperating with the rotary forging machine for forming, the production efficiency is high. At the same time, without removing materials, the deformation ability of the metal can be improved, its characteristics can be fully exerted, and a greater tooth hardness can be obtained. In terms of the accuracy of the tooth shape, the surface quality and the metal material structure of the tooth part, the cold forging rack forming can also greatly improve the performance of the rack.

[0049] The rack processing method of the present invention solves the problem of difficult processing of quenched and tempered parts through cold forging rotary forging. Utilizing the rotary forging principle, the teeth are hardened, the service life of the rack is improved, and it is suitable for large - batch automated production.

[0050] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. A rack rotary forging machine, characterized in that, It includes an upper die, a lower die, a swing part and a pushing part. The bottom surface of the upper die is provided with forming teeth. The upper surface of the lower die is provided with a placement groove. The swing part drives the upper die to swing around the forming axis. The pushing part drives the lower die to move vertically. A rack blank is arranged between the upper die and the lower die. The rack blank is fixed in the placement groove. The forming teeth contact the rack blank for rotary forging.

2. The rack rotary swaging machine according to claim 1, characterized in that, The pushing part includes a lower slider and an oil cylinder. The telescopic rod of the oil cylinder is fixedly connected to the lower slider. The lower die is fixedly arranged on the upper surface of the lower slider. The oil cylinder adjusts and controls the vertical movement of the lower slider.

3. The rack rotary forging machine according to claim 2, characterized in that, The swing part includes a swing assembly, a swing head and an upper positioning plate. The swing assembly is fixedly connected to the swing head. The swing head is arranged on the upper positioning plate. The upper die is fixedly arranged on the swing head. The upper positioning plate is fixedly arranged. A swing groove is arranged on the upper positioning plate. The swing head is arranged in the swing groove. The swing head is provided with a swing surface. The groove surface of the swing groove and the swing surface are arc surfaces arranged in cooperation. And the radius of the groove surface of the swing groove is the same as the radius of the swing surface. The groove surface of the swing groove and the swing surface slide relative to each other.

4. The rack rotary forging machine according to claim 3, characterized in that, The forming axis is parallel to the axis of the rack blank. And during rotary forging forming, the forming axis and the axis of the rack blank are coaxially arranged.

5. The rack rotary swaging machine according to claim 3, characterized in that, The swing assembly includes a connecting plate, a connecting shaft, a connecting rod, an eccentric shaft and a rotating wheel. The eccentric shaft is eccentrically arranged on the rotating wheel. The axis of the eccentric shaft, the axis of the connecting shaft and the axis of the rotating wheel are parallelly arranged. The two ends of the connecting rod are respectively rotatably connected to the connecting shaft and the eccentric shaft. The connecting shaft is fixedly connected to one end of the connecting plate. The other end of the connecting plate is fixedly connected to the swing head.

6. The rack rotary forging machine according to claim 5, characterized in that The connecting plate and the swing head are fixed by a positioning pin. The positioning pin is a straight rod with a polygonal cross-section. Positioning holes corresponding to the positioning pin are arranged on both the connecting plate and the swing head. The positioning pin is simultaneously arranged in the positioning holes of the connecting plate and the swing head.

7. A rack processing method, characterized in that, Using the rack rotary forging machine as described in claim 6, it includes the steps: S1, blanking; Obtaining a cylindrical blank through blanking; S2, pre-spraying and heating; Heating the cylindrical blank and pre-spraying graphite; S3, rack rotary forging; Putting the pre-sprayed cylindrical blank into the lower die. The pushing part drives the lower die to move upward until the cylindrical blank is in pressure contact with the upper die. The swing head swings reciprocally to perform rotary forging on the cylindrical blank to extrude the tooth surface shape to obtain the final product.

8. The rack processing method according to claim 7, characterized in that In step S2, the cylindrical blank is heated to 160°C to 180°C.

9. The rack processing method according to claim 7, characterized in that In step S3, the swing amplitude of the swing head is ±3° with the vertical line as the center line and the forming axis as the center.

10. The rack processing method according to claim 7, characterized in that, The process of step S3 is as follows: The upward movement of the oil cylinder drives the downward slider to move upward. Place the cylindrical blank in the lower mold. When the lower mold and the upper mold are closed, the eccentric shaft rotates eccentrically and is transmitted to the connecting shaft through the connecting rod. The connecting plate is fixed by the positioning pin and the swing head to drive the upper mold to swing reciprocally to achieve the purpose of rotary forging.

Images