Bolt forging combined tool and using method

Abstract

The invention relates to the technical field of bolt forging, in particular to a bolt forging combined tool and a using method.The bolt forging combined tool comprises a rack, a hydraulic cylinder and a supporting rod and further comprises a movable die assembly, an electromagnetic coil, a top plate, a fixed die assembly, a transmission assembly, a connecting assembly and a side groove, the movable die assembly is connected with the hydraulic cylinder, and the hydraulic cylinder extends to the inner side of the movable die assembly; the electromagnetic coil is installed between the inner walls of the rack, the top plate is installed on the top of the rack, and the fixed mold assembly is rotationally installed at the bottom of the top plate. The corresponding top dies are sequentially switched in the ascending process of the blank along with the bottom die, and the blank is subjected to secondary heating before entering the corresponding top dies to make up heat loss of the blank, so that the problem that the blank needs to be transferred for multiple times when a single blank is forged in a three-pass forming mode is solved; and the problem that the forging efficiency of the brake lever bolt is low due to the fact that the strain uniformity becomes poor due to temperature reduction in the blank transferring process and secondary heating is needed is solved.

Description

Technical Field

[0001] The invention relates to the technical field of bolt forging, and in particular to a bolt forging combined tooling and a use method thereof. Background Art

[0002] Brake lever bolts are key components in the braking system of high-speed locomotives. They are extremely important in the braking system of locomotives. Their quality directly affects the safety of locomotive operation. Therefore, high requirements are placed on their strength. Alloy steel is usually used as the raw material to make blanks, and the blanks are processed by forging to obtain brake lever bolts with strength that meets or exceeds the design standards.

[0003] Bolt forging methods can be divided into cold forging and hot forging. Since high-speed rail brake bolts need to have good strength and toughness, hot forging can improve the plasticity of the material at high temperature, making it easy to form, and can forge complex shapes. In addition, subsequent heat treatment after hot forging can further enhance its mechanical properties and wear resistance. Therefore, high-speed rail brake bolts are processed by hot forging.

[0004] Conventional bolts give priority to production efficiency and adopt a single-pass forging method for bolt production. During the bolt forging process, the maximum equivalent strain occurs at the connection position between the bolt head and the rod. The metal flow law here is complex. It is the last area to be filled and it is also a dangerous area in the entire hot forging process. The strain increment of single-pass forming is fixed, and the strain amount in single-pass forming is relatively large, and the forming difficulty of the hot forging process is relatively high. Compared with single-pass forming, the strain of three-pass forming gradually increases, and the strain increment of each pass is small, which can disperse the excessive strain amount in single-pass forming and reduce the forming difficulty of the hot forging process. Therefore, the filling effect of the brake lever bolt using the three-pass forming billet forging method is better.

[0005] In the prior art, when the brake lever bolt is forged by a three-pass forming method, in order to improve the forging efficiency of the brake lever bolt, the corresponding forging dies are placed side by side, and the bolt blank is taken out of the die and placed in the next die after each forming forging is completed. However, during the production process, after the bolt blank is heated to a certain temperature and placed in the die, the contact surface between the blank and the die is heat transferred by heat conduction. During the process of transferring the blank to the next die, the free surface of the blank exchanges heat with the external environment by convection and radiation, causing the second and third pass blank forging temperatures to drop significantly, and the strain uniformity of the blank deteriorates after the temperature drops. In order to prevent the bolt forging quality from being affected by the deterioration of strain uniformity caused by the temperature drop, it is necessary to heat the bolt blank again after taking out the bolt blank, resulting in low efficiency when the brake lever bolt is forged by a three-pass forming method.

[0006] Therefore, a bolt forging combined tooling and a use method are proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a bolt forging combination tooling and a method of using it. By switching the corresponding top dies in sequence as the blank rises with the bottom die, and performing secondary heating on the blank before the blank enters the corresponding top die to compensate for the heat loss of the blank, the problem of multiple transfers of the blank when forging a single blank through a three-pass forming method is solved, and the problem of poor strain uniformity of the blank during the transfer process due to the decrease in temperature, requiring secondary heating, resulting in low forging efficiency of the brake lever bolt is solved. The tooling has the effect of fully guaranteeing the forging quality of the brake lever bolt and ensuring the forging efficiency of the brake lever bolt.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] Compared with single-pass forming, the filling effect of the blank in three-pass forming is better. The corresponding aspect ratio of the blank is calculated by the aspect ratio of the bolt head to ensure that the blank can fill the entire mold during the flow process. However, the forging quality of the bolt is also related to the initial hot forging temperature of the head. Different initial hot forging temperatures of the head will affect the difference in metal deformation at the center and surface of the bolt head. Taking GH4169 high-temperature alloy as an example, when the initial hot forging temperature of the head is 950℃, the strain difference between the center and the surface is the largest, with a maximum value of 0.95. As the hot forging temperature increases, the strain difference gradually decreases. When the initial hot forging temperature of the head is 1050℃, the change of the surface-center strain is the most gentle, and the strain difference is 0.5. Therefore, when forging the brake lever bolt, the temperature of the bolt blank head needs to be maintained in the optimal hot forging temperature range of the corresponding material. However, the forging operations of different passes need to transfer the blank to the corresponding pass mold. During the transfer process, the blank temperature exchanges heat with the external environment, causing the blank temperature to decrease.

[0010] A bolt forging combined tooling comprises a frame, a hydraulic cylinder, a support rod, a movable die assembly, an electromagnetic coil, a top plate, a fixed die assembly, a transmission assembly, a connecting assembly and a side groove, wherein the movable die assembly is connected to the hydraulic cylinder, the electromagnetic coil is installed between the inner walls of the frame, the top plate is installed on the top of the frame, the fixed die assembly is rotatably installed at the bottom of the top plate, and the fixed die assembly comprises a plurality of top dies, the transmission assembly is installed between the side walls of the frame, and the transmission assembly is meshed with the fixed die assembly, the connecting assembly is connected to the movable die assembly, and the connecting assembly is electrically connected to the electromagnetic coil, the side groove is provided on the inner wall of one side of the frame, the end of the connecting assembly extends into the side groove, a pressing block is installed in the side groove, when the hydraulic cylinder extends to lift the movable die assembly, the connecting assembly is limited by the side groove and moves upward with the movable die assembly, when the connecting assembly moves upward, the corresponding top die is switched by the transmission assembly to be above the movable die assembly, and the connecting assembly is connected to the electromagnetic coil power supply within a set time period, and when the hydraulic cylinder contracts to lower the movable die assembly, the connecting assembly is separated from the transmission assembly by misalignment.

[0011] In the above design, due to the adoption of a three-pass forging method, the number of molds in the movable mold assembly is three. After the single-pass forging of the billet is completed, there is no need to remove the billet from the movable mold assembly. It is only necessary to continue to repeatedly start the hydraulic cylinder. In the process of the hydraulic cylinder top starting the movable mold assembly to the highest point, under the action of the side groove, the distance between the connecting assembly and the movable mold assembly is the largest during the rising process. The connecting assembly can engage with the transmission assembly when moving up, thereby driving the fixed mold assembly to rotate 120°, and in the rising process, for a period of time before the head of the billet enters the fixed mold assembly, the power supply of the electromagnetic coil is turned on under the restriction of the movement trajectory of the connecting assembly, thereby compensating for the heat lost due to heat exchange between the billet and the movable mold assembly. Therefore, while fully ensuring the forging quality of the brake lever bolt, the forging efficiency of the brake lever bolt is greatly improved at the same time.

[0012] Preferably, the connecting assembly includes a rack, a slider, an insert rod, a bending rod, an extrusion block and a push switch, the rack is slidably fitted with the movable mold assembly, the slider is installed at the bottom of the rack, the insert rod and the bending rod are both installed on the side wall of the rack, the extrusion block is installed at the end of the bending rod, and the push switch is installed on the inner wall of the frame, and the extrusion block applies pressure to the push switch and turns on the power supply of the electromagnetic coil when the bending rod moves up with the rack.

[0013] In the above design, since the heat loss due to heat exchange between the blank and the movable mold assembly is limited, the temperature of the blank head can be raised to the optimal forging temperature by only briefly heating the blank head. When the connecting assembly moves upward with the movable mold assembly, it moves along the longer side of the side groove. After the extrusion block moves upward, it can squeeze the press switch until the power of the electromagnetic coil is connected during the separation of the extrusion block and the press switch. In this way, the blank head can be heated and excessive heating of the blank head can be avoided, which is beneficial to energy saving. In addition, when the connecting assembly moves downward with the movable mold assembly, the extrusion block moves downward accordingly and is misaligned with the press switch, and can fall normally without squeezing the press switch, effectively preventing the electromagnetic coil power from being turned on when the blank is reset, causing energy waste.

[0014] Preferably, the transmission assembly includes a transmission shaft, transmission teeth, a drive shaft and drive teeth, the transmission shaft is installed on the side wall of the frame, the transmission teeth are installed on the transmission shaft, the drive shaft is installed on the inner wall of the frame, the drive teeth are installed on the drive shaft, and the transmission shaft and the drive shaft are connected via a bevel gear set.

[0015] In the above design, the transmission shaft and the drive shaft are connected by a bevel gear set. The vertical movement of the hydraulic cylinder can be used to provide power for the transmission assembly and horizontally change the horizontal angle of the fixed mold assembly. In addition, by changing the module ratio of the drive teeth and the transmission teeth, the rotation angle of the fixed mold assembly can be conveniently adjusted.

[0016] Preferably, the movable mold assembly includes a ring sleeve, a bottom mold, a bottom plate, an annular groove and an oxide scale discharge outlet. The bottom mold is installed on the inner circumference of the ring sleeve, and the bottom of the bottom mold is flush with the bottom of the ring sleeve. The annular groove is constructed on the inner circumference of the bottom mold. The bottom plate is slidably arranged in the annular groove, and the bottom of the bottom plate is connected to the hydraulic cylinder. The oxide scale discharge outlet is opened on the outer circumference of the bottom mold, and the oxide scale discharge outlet is connected to the annular groove. The surface of the ring sleeve is provided with a straight groove adapted to the slider.

[0017] In the above design, when the hydraulic cylinder extends to lift the bottom die, the bottom plate moves up along the annular groove to the highest point before the bottom die moves up accordingly. When the bottom plate moves up to the highest point, the blank can be separated from the oxide scale discharge port, thereby reducing the heat loss of the blank. When the three-pass forming forging is completed, the blank is taken out from the bottom die, and the oxide scale formed on the blank falls into the bottom die and can be easily discharged from the oxide scale discharge port, thereby avoiding the oxide scale formed during the forging process of the blank from accumulating in the bottom die and affecting the forming size of the blank, further fully ensuring the forming quality of the brake lever bolt.

[0018] Preferably, the fixed mold assembly also includes an arc-shaped connecting rod, a limit block and a gear ring, the inner circumference of the gear ring is engaged with the driving teeth, and the gear ring is installed between multiple top molds, the arc-shaped connecting rod is installed between adjacent top molds, and the limit block is installed on the top of the top mold.

[0019] In the above design, the module of the gear ring is designed according to the module ratio of the driving tooth and the transmission tooth. When three passes of forming forging are performed, the hydraulic cylinder is extended once and the top die is rotated 120°. When other numbers of forming forging are performed, the corresponding adjustment can be made according to the number of top dies.

[0020] Preferably, a limiting groove is provided at the bottom of the top plate, and the limiting groove is matched with the limiting block.

[0021] In the above design, with the cooperation of the limit groove and the limit block, not only can the fixed die assembly rotate in accordance with the bottom surface of the top plate, but also the top die can fully fit with the top plate during stamping forging, thereby ensuring the stability of the top die during forging and helping to improve the forging quality of the brake lever bolt.

[0022] Preferably, a tooth groove is provided on the upper portion of the side wall of the rack, and the tooth groove on the rack is provided on the side of the rack away from the bottom mold.

[0023] In the above design, the oxide scale generated during the forging of the brake lever bolt will fall from the top of the bottom die to the surrounding areas after breaking. Since the tooth groove is set away from one side of the bottom die, the broken and falling oxide scale will not fall into the tooth groove, ensuring the effective engagement of the rack tooth groove and the transmission tooth.

[0024] Preferably, the edge of the scale discharge port is flush with the surface of the bottom plate when it is at the lowest point, and the cross-section of the bottom plate is trapezoidal.

[0025] In the above design, when the bottom plate moves down to the lowest position, the oxide scale debris remaining in the bottom mold can be easily discharged from the oxide scale discharge port.

[0026] Preferably, the side section of the side groove is an isosceles trapezoid, and the longer side is arranged on the side away from the push switch.

[0027] In the above design, when the end of the insertion rod enters the oblique edge of the side groove, it can drive the rack to translate quickly and be dislocated and separated from the transmission tooth.

[0028] A method for using a bolt forging assembly tool comprises the following steps:

[0029] S1. The high-speed rail brake bolt blanks which are pre-cut to the same length are placed inside the bottom die after being heated. When the hydraulic cylinder is extended, the bottom plate is first lifted up, and a part of the top of the blank is exposed from the bottom die. When the top of the bottom plate fits with the top of the annular groove, the bottom die, the ring sleeve and the bottom plate are moved up together, and a part of the top of the blank is exposed from the bottom die.

[0030] S2. When the ring sleeve moves upward, it drives the rack upward, and the end of the insertion rod moves to one side along the longer side of the side groove. At this time, the rack is at the maximum distance from the bottom mold under the cooperation of the insertion rod and the side groove. During the continuous upward movement of the rack, the rack meshes with the transmission gear until the separation process. After the rack meshes with the transmission gear and continues to move upward, the transmission gear rotates and drives the transmission shaft to rotate. The transmission shaft drives the drive shaft and the drive gear to rotate through the bevel gear set. Under the cooperation of the drive gear and the gear ring, the fixed mold assembly is driven to rotate, and the top mold with mold cavities a, b, and c opened inside is rotated to the top of the bottom mold in sequence;

[0031] S3, before the top of the blank enters the top die, when the extrusion block moves up with the ring sleeve through the bending rod and contacts the push switch, the extrusion block presses the push switch, thereby turning on the power of the electromagnetic coil to compensate for the heat loss of the blank after it is placed on the bottom die. In the subsequent process of the extrusion block continuing to move up with the ring sleeve, the extrusion block separates from the push switch, and the blank completely enters the top die to complete the forging of the corresponding shape. At this time, the plunger moves to the highest point of the side groove, and the upper push block is reset after being pressed, and presses the plunger from the bottom;

[0032] S4, then the hydraulic cylinder contracts, the ring sleeve, the bottom die, the bottom plate, and the rack move downward together, and the plunger moves along the oblique side of the side groove to the side of the shorter side of the side groove. At this time, the distance between the rack, the bending rod, and the extrusion block and the bottom die is reduced. In the subsequent downward movement process, the rack does not mesh with the transmission gear, and the extrusion block does not contact the press switch. When the plunger moves to the lowest point, the end of the plunger enters the side of the longer side from the shorter side of the side groove and squeezes the pressing block below. When the plunger moves upward, it moves along the side of the longer side of the side groove;

[0033] S5. After the hydraulic cylinder shrinks to the initial position, it expands and contracts twice, and the three top dies rotate one circle. The forging operation of a single high-speed rail brake bolt blank is completed. The forged high-speed rail brake bolt is removed from the bottom die for subsequent processing steps, and a new heated blank is placed in the bottom die.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention provides side grooves and connecting components. When the hydraulic cylinder is extended and contracted, the insertion rod in the connecting component moves along different sides of the side groove, so that the distance between the rack and the bottom die changes adaptively, thereby correspondingly controlling the engagement and separation of the connecting component and the transmission component. When the hydraulic cylinder is extended, the connecting component is engaged with the transmission component, and the fixed die component can be accurately controlled to rotate 120°, and the corresponding top die can be switched to above the bottom die. After one forming forging pass is completed, when performing the subsequent forming forging operation, there is no need to remove the blank from the bottom die, and the top die corresponding to the subsequent pass can be accurately rotated to above the bottom die, which is beneficial to saving the time spent on forging and can improve the forging efficiency of the brake lever bolt; at the same time, it can reduce the heat loss during the transfer of the blank, and avoid a significant decrease in the temperature of the blank resulting in a significant deterioration in strain uniformity.

[0036] 2. The present invention provides an electromagnetic coil, a connecting assembly and a side groove. When the hydraulic cylinder is extended, the extrusion block can apply pressure to the push switch during the upward movement. During the time period from the contact to the separation of the extrusion block and the push switch, the electromagnetic coil is turned on to heat the head of the blank, replenishing the heat lost by the heat exchange between the blank and the top die and the bottom die, and raising the temperature of the blank head to the optimal forging temperature, thereby effectively ensuring the forging quality of the bolt.

[0037] 3. The present invention provides a movable die assembly, and when the hydraulic cylinder extends to lift the bottom die, the bottom plate moves up to the highest point to separate the blank from the oxide scale discharge port, thereby reducing the heat loss of the blank; when the three-pass forming forging is completed, the blank is taken out from the bottom die, and the oxide scale formed on the blank falls into the bottom die and can be easily discharged from the oxide scale discharge port, thereby preventing the oxide scale formed during the forging process of the blank from accumulating in the bottom die and affecting the forming size of the blank, thereby further ensuring the forming quality of the brake lever bolt. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0039] Figure 2 It is a structural schematic diagram of the frame of the present invention;

[0040] Figure 3 It is a structural schematic diagram of the connection assembly of the present invention;

[0041] Figure 4 It is a structural schematic diagram of the transmission assembly of the present invention;

[0042] Figure 5 is a cross-sectional view of the movable mold assembly of the present invention;

[0043] Figure 6 It is a structural schematic diagram of the fixed mold assembly of the present invention;

[0044] Figure 7 is a cross-sectional view of the top plate of the present invention;

[0045] Figure 8 It is a cross-sectional view corresponding to three top molds of the present invention;

[0046] Fig. 9 It is a structural schematic diagram of the connection assembly of the hydraulic cylinder of the present invention when it is in an extended state;

[0047] Fig.10 It is a schematic structural diagram of the connecting assembly of the hydraulic cylinder of the present invention when it is in a retracted state.

[0048] In the figure: 1. frame; 2. hydraulic cylinder; 3. support rod; 4. movable mold assembly; 41. ring sleeve; 411. straight slide groove; 42. bottom mold; 43. bottom plate; 44. annular groove; 45. oxide scale discharge port; 5. electromagnetic coil; 6. top plate; 61. limit groove; 7. fixed mold assembly; 71. top mold; 72. arc connecting rod; 73. limit block; 74. gear ring; 8. transmission assembly; 81. transmission shaft; 82. transmission gear; 83. drive shaft; 84. drive gear; 9. connecting assembly; 91. rack; 92. slider; 93. plug rod; 94. bending rod; 95. extrusion block; 96. press switch; 10. side groove; 101. press block. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] See also Figures 1 to 10 The present invention provides a bolt forging assembly tool and a method of use, and the technical solution is as follows:

[0051] Reference Figure 1 and Figure 2A bolt forging assembly tool comprises a frame 1, a hydraulic cylinder 2, and a support rod 3. The hydraulic cylinder 2 is installed at the center of the inner bottom surface of the frame 1. The support rod 3 is distributed on the frame 1 in a ring array with respect to the hydraulic cylinder 2. It also comprises a movable mold assembly 4, an electromagnetic coil 5, a top plate 6, a fixed mold assembly 7, a transmission assembly 8, a connecting assembly 9 and a side groove 10. The movable mold assembly 4 is installed and connected with the hydraulic cylinder 2. The top of the hydraulic cylinder 2 extends to the inner side of the movable mold assembly 4. The electromagnetic coil 5 is installed between the inner walls of the frame 1. The power of the electromagnetic coil 5 is designed and selected according to the material of the brake lever bolt. The top plate 6 is installed on the top of the frame 1. The fixed mold assembly 7 is rotatably installed. At the bottom of the top plate 6, the fixed die assembly 7 includes a plurality of top dies 71, the number of which is selected according to the number of forming passes. Since the present application adopts a three-pass forming forging method, the number of top dies 71 is set to 3. The transmission assembly 8 is installed between the side walls of the frame 1, and the transmission assembly 8 is meshed with the fixed die assembly 7. The connecting assembly 9 is installed and connected with the movable die assembly 4, and the connecting assembly 9 is electrically connected with the electromagnetic coil 5. The side groove 10 is opened on the inner wall of one side of the frame 1. The side view cross-section of the side groove 10 is an isosceles trapezoid, and the longer side is set on the side away from the press switch 96. The end of the connecting assembly 9 extends into the side groove 10, and the side groove 10 is A pressing block 101 is installed. The pressing block 101 is located at the corner of the longer side of the side groove 10 and is used to limit the unidirectional cyclic movement of the connecting component 9 along the side groove 10. When the hydraulic cylinder 2 extends to lift the movable mold component 4, the connecting component 9 is limited by the side groove 10 and moves up with the movable mold component 4. When the connecting component 9 moves up, the corresponding top mold 71 is switched to the top of the movable mold component 4 through the transmission component 8. After the movable mold component 4 moves up under the action of the hydraulic cylinder 2, a single-pass forming forging operation is completed through the cooperation of a single top mold 71 and the movable mold component 4. When moving up, after the connecting component 9 produces a horizontal displacement, the connecting component 9 subsequently moves up with the movable mold component 4 and can cooperate with the transmission component 8. The fixed die assembly 7 is meshed, thereby the transmission assembly 8 drives the fixed die assembly 7 to rotate, and the connecting assembly 9 connects to the power supply of the electromagnetic coil 5 within the set time period. During the time period when the electromagnetic coil 5 is powered on, the head of the blank is heated for the second time by electromagnetic heating, so that the temperature of the blank is at a suitable initial hot forging temperature. When the hydraulic cylinder 2 contracts and lowers the movable die assembly 4, the connecting assembly 9 is dislocated and separated from the transmission assembly 8. When the hydraulic cylinder 2 contracts, the connecting assembly 9 moves horizontally to one side of the movable die assembly 4. When the connecting assembly 9 moves down subsequently, it is separated from the transmission assembly 8 to avoid resetting the fixed die assembly 7, and the power supply of the electromagnetic coil 5 is always in a disconnected state.

[0052] Reference Figure 3 , Fig. 9 and Fig.10As an embodiment of the present invention, specifically, the connecting assembly 9 includes a rack 91, a slider 92, an insert rod 93, a bending rod 94, an extrusion block 95 and a press switch 96. The rack 91 is slidably fitted with the movable mold assembly 4, the slider 92 is mounted at the bottom of the rack 91, the insert rod 93 and the bending rod 94 are both mounted on the side wall of the rack 91, the extrusion block 95 is mounted at the end of the bending rod 94, and the press switch 96 is mounted on the inner wall of the frame 1. When the extrusion block 95 moves up with the rack 91 through the bending rod 94, it applies pressure to the press switch 96 and turns on the power supply of the electromagnetic coil 5; when the hydraulic cylinder 2 is extended, the end of the insert rod 93 is located in the side groove of the slot away from the bottom mold 42, that is, at this time, the distance between the rack 91 and the bottom mold 42 is the largest, and when the rack 91 moves up with the ring sleeve 41 It will mesh with the transmission assembly 8, thereby driving the fixed mold assembly 7 to rotate 120° through the transmission assembly 8, switching the corresponding top mold 71 to above the bottom mold 42, and the position of the push switch 96 remains unchanged. At this time, the distance between the extrusion block 95 and the push switch 96 is the smallest. During the time period from the push switch 96 moving up and contacting to separating from the push switch 96, the power supply of the electromagnetic coil 5 is turned on by applying pressure to the push switch 96, and then the electromagnetic coil 5 is used to heat the head of the blank to make up for the heat lost from the head of the blank; when the hydraulic cylinder 2 contracts subsequently, the end of the insertion rod 93 is located in the side groove of the side groove 10 close to the bottom mold 42, and then the rack 91 will not drive the transmission tooth 82 to rotate in the opposite direction when it moves down, and the extrusion block 95 can also avoid contact with the push switch 96 and reset smoothly.

[0053] Reference Figure 4 As an embodiment of the present invention, specifically, the transmission assembly 8 includes a transmission shaft 81, a transmission tooth 82, a drive shaft 83 and a drive tooth 84. The transmission shaft 81 is installed on the side wall of the frame 1, the transmission tooth 82 is installed on the transmission shaft 81, the drive shaft 83 is installed on the inner wall of the frame 1, and the drive tooth 84 is installed on the drive shaft 83. The transmission shaft 81 and the drive shaft 83 are connected through a bevel gear set; the transmission tooth 82 and the drive tooth 84 are respectively installed on the transmission shaft 81 and the drive shaft 83 through keyway matching, and the bevel gear set is composed of two sets of bevel gears of different sizes and shapes.

[0054] Reference Figure 5As an embodiment of the present invention, specifically, the movable mold assembly 4 includes a ring sleeve 41, a bottom mold 42, a bottom plate 43, an annular groove 44 and an oxide scale discharge port 45. The bottom mold 42 is installed on the outer periphery of the ring sleeve 41, and the bottom of the bottom mold 42 is flush with the bottom of the ring sleeve 41. The annular groove 44 is constructed on the inner periphery of the bottom mold 42. The bottom plate 43 is slidably arranged in the annular groove 44, and the bottom of the bottom plate 43 is connected to the hydraulic cylinder 2. The oxide scale discharge port 45 is opened on the outer periphery of the bottom mold 42, and the oxide scale discharge port 45 is connected to the annular groove 44. The surface of the ring sleeve 41 is provided with a straight groove 411 adapted to the slider 92; when the hydraulic cylinder 2 is extended, the bottom plate 43 moves up along the annular groove 44 to the highest point, and then the bottom mold 42 moves up accordingly. When the bottom plate 43 moves up, the blank is connected to the bottom mold 42. The scale discharge port 45 is separated. After the three-pass forming forging is completed, when the bottom plate 43 has not completely dropped to the lowest point, the blank with its head exposed above the bottom die 42 can be taken out from the bottom die 42, and the scale formed on the blank falls into the bottom die 42. The scale that falls into the bottom die 42 can be easily sucked out through the scale discharge port 45, so as to avoid the bottom die 42 accumulating in the bottom die 42 and causing the blank to be placed on the surface of the bottom plate 43 to be unable to be at a suitable height; in use, a scale collection box corresponding to the scale discharge port 45 is placed on the surface of the ring sleeve 41, so as to avoid the scale from falling into the straight chute 411. In addition, if the scale falls into the straight chute 411, it can also be sucked out of the straight chute 411 by a vacuuming device.

[0055] Reference Figure 6 As an embodiment of the present invention, specifically, the fixed mold assembly 7 further includes an arc-shaped connecting rod 72, a limit block 73 and a gear ring 74, the inner circumference of the gear ring 74 is meshed with the driving teeth 84, and the gear ring 74 is installed between a plurality of top molds 71, the arc-shaped connecting rod 72 is installed between adjacent top molds 71, and the limit block 73 is installed on the top of the top mold 71; refer to Figure 8 The top die 71 used in the three-pass forming forging method has die cavities a, b, and c opened inside. When the hydraulic cylinder 2 extends and drives the movable die assembly 4 to move upward, during the meshing process of the rack 91 and the transmission tooth 82, the meshing of the driving tooth 84 and the gear ring 74 drives the gear ring 74 to rotate 120°, thereby making the top die 71 corresponding to the three die cavities a, b, and c rotate in turn to the top of the bottom die 42.

[0056] Reference Figure 7 As an implementation mode of the present invention, specifically, a limiting groove 61 is provided at the bottom of the top plate 6, and the limiting groove 61 is adapted to the limiting block 73; when the fixed die assembly 7 rotates, it fits the bottom surface of the top plate 6, and during stamping and forging, the top die 71 is in a stationary state and fully fits the top plate 6.

[0057] Reference Fig. 9As an embodiment of the present invention, specifically, a tooth groove is provided on the upper part of the side wall of the rack 91, and the tooth groove on the rack 91 is provided on the side of the rack 91 away from the bottom mold 42; after the oxide scale is broken, it will fall from the top of the bottom mold 42 to the surroundings and will not fall into the tooth groove.

[0058] Reference Figure 5 As an embodiment of the present invention, specifically, the edge of the oxide scale discharge port 45 is flush with the surface of the bottom plate 43 when it is at the lowest point, and the cross-section of the bottom plate 43 is a trapezoid; when the bottom plate 43 moves down to the lowest point, an air gun is used to blow air into the oxide scale discharge port 45 or a cleaning tool is inserted into the oxide scale discharge port 45 to remove the oxide scale in the bottom mold 42.

[0059] A method for using a bolt forging assembly tool comprises the following steps:

[0060] S1. The high-speed rail brake bolt blanks are pre-cut to the same length, and after being heated, they are placed inside the bottom die 42. When the hydraulic cylinder 2 is extended, the bottom plate 43 is first lifted up, and the bottom plate 43 slowly moves up along the annular groove 44. When the top of the bottom plate 43 fits the top of the annular groove 44, the bottom die 42, the ring sleeve 41 and the bottom plate 43 move up together when the hydraulic cylinder 2 continues to extend. At this time, a part of the top of the blank is exposed from the bottom die 42, and the exposed part of the blank is the forging part;

[0061] S2, when the ring sleeve 41 moves upward, it drives the rack 91 upward, and the end of the insertion rod 93 moves along the longer side of the side groove 10. At this time, the rack 91 is at the maximum distance from the bottom mold 42 under the cooperation of the insertion rod 93 and the side groove 10. During the continuous upward movement of the rack 91, the tooth groove part of the rack 91 meshes with the transmission tooth 82. During the meshing and separation process between the rack 91 and the transmission tooth 82, the transmission tooth 82 rotates and drives the transmission shaft 81 to rotate. The transmission shaft 81 drives the drive shaft 83 and the drive tooth 84 to rotate through the bevel gear set. Under the cooperation of the drive tooth 84 and the gear ring 74, the fixed mold assembly 7 is driven to rotate, and the top mold 71 with the a, b, and c mold cavities opened inside is rotated to the top of the bottom mold 42 in sequence. During the single extension process of the hydraulic cylinder 2, only a single top mold 71 is located above the bottom mold 42;

[0062] S3, before the top of the blank enters the interior of the top die 71, when the extrusion block 95 moves up with the ring sleeve 41 through the bending rod 94 and contacts the push switch 96, the extrusion block 95 applies pressure to the push switch 96, turns on the power of the electromagnetic coil 5, heats the blank, and compensates for the heat loss after the blank is placed on the bottom die 42. In the subsequent process of the extrusion block 95 continuing to move up with the ring sleeve 41, the extrusion block 95 is separated from the push switch 96, and the tooth groove of the rack 91 is separated from the transmission tooth 82. When the rack 91 continues to move up, the gear ring 74 will not continue to rotate, ensuring that the corresponding top die 71 stops above the bottom die 42, and the blank completely enters the top die 71 to complete the forging of the corresponding shape. At this time, the insertion rod 93 moves to the highest point of the side groove 10, and the upper pressing block 101 is reset after being pressed, and presses the insertion rod 93 from the bottom;

[0063] S4, then the hydraulic cylinder 2 contracts, the ring sleeve 41, the bottom mold 42, the bottom plate 43, and the rack 91 move downward together, and the insertion rod 93 moves along the oblique side of the side groove 10 to the side of the shorter side of the side groove 10. At this time, the distance between the rack 91, the bending rod 94 and the extrusion block 95 and the bottom mold 42 is reduced. In the subsequent downward movement process, the rack 91 does not mesh with the transmission tooth 82, and the extrusion block 95 does not contact the press switch 96. When the insertion rod 93 moves to the lowest point, the end of the insertion rod 93 enters the longer side from the shorter side of the side groove 10 and squeezes the pressing block 101 below. Then the pressing block 101 resets the limit of the end of the insertion rod 93, so that the subsequent insertion rod 93 moves along the longer side of the side groove 10 when it moves upward;

[0064] S5. After the hydraulic cylinder 2 shrinks to the initial position, it expands and contracts twice, and the three top dies 71 rotate one circle. The forging operation of a single high-speed rail brake bolt blank is completed, and the forged high-speed rail brake bolt is removed from the bottom die 42 for subsequent processing steps. Then, the oxide scale that falls into the bottom die 42 during the forging of the blank is cleaned through the oxide scale discharge port 45. After the oxide scale is cleaned, a new heated blank is placed in the bottom die 42, and the above forging operation is repeated.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A bolt forging assembly tool, comprising a frame (1), a hydraulic cylinder (2), and a support rod (3), characterized in that: The invention also comprises a movable mold assembly (4), an electromagnetic coil (5), a top plate (6), a fixed mold assembly (7), a transmission assembly (8), a connecting assembly (9) and a side groove (10), wherein the movable mold assembly (4) is connected to the hydraulic cylinder (2), the electromagnetic coil (5) is installed between the inner walls of the frame (1), the top plate (6) is installed on the top of the frame (1), the fixed mold assembly (7) is rotatably installed on the bottom of the top plate (6), and the fixed mold assembly (7) comprises a plurality of top molds (71), the transmission assembly (8) is installed between the side walls of the frame (1), and the transmission assembly (8) is meshed with the fixed mold assembly (7), the connecting assembly (9) is connected to the movable mold assembly (4), and the connecting assembly (9) is connected to the electromagnetic coil (5). The magnetic coil (5) is electrically connected, the side groove (10) is provided on the inner wall of one side of the frame (1), the end of the connecting component (9) extends into the side groove (10), a pressing block (101) is installed in the side groove (10), when the hydraulic cylinder (2) extends to lift the movable mold assembly (4), the connecting component (9) is limited by the side groove (10) and moves upward with the movable mold assembly (4), when the connecting component (9) moves upward, the corresponding top mold (71) is switched by the transmission assembly (8) to the top of the movable mold assembly (4), and the connecting component (9) is connected to the power supply of the electromagnetic coil (5) within a set time period, and when the hydraulic cylinder (2) contracts to lower the movable mold assembly (4), the connecting component (9) and the transmission assembly (8) are dislocated and separated.

2. The bolt forging assembly tool according to claim 1, characterized in that: The connecting assembly (9) comprises a rack (91), a slider (92), an insert rod (93), a bending rod (94), an extrusion block (95) and a push switch (96); the rack (91) is slidably fitted with the movable mold assembly (4); the slider (92) is mounted at the bottom of the rack (91); the insert rod (93) and the bending rod (94) are both mounted on the side wall of the rack (91); the extrusion block (95) is mounted at the end of the bending rod (94); the push switch (96) is mounted on the inner wall of the frame (1); and the extrusion block (95) applies pressure to the push switch (96) and turns on the power supply of the electromagnetic coil (5) when the bending rod (94) moves upward along with the rack (91).

3. The bolt forging assembly tool according to claim 2, characterized in that: The transmission assembly (8) comprises a transmission shaft (81), a transmission tooth (82), a drive shaft (83) and a drive tooth (84); the transmission shaft (81) is mounted on a side wall of a frame (1); the transmission tooth (82) is mounted on the transmission shaft (81); the drive shaft (83) is mounted on an inner wall of the frame (1); the drive tooth (84) is mounted on the drive shaft (83); and the transmission shaft (81) and the drive shaft (83) are connected via a bevel gear set.

4. The bolt forging assembly tool according to claim 3, characterized in that: The movable mold assembly (4) comprises a ring sleeve (41), a bottom mold (42), a bottom plate (43), an annular groove (44) and an oxide scale discharge port (45); the bottom mold (42) is mounted on the inner periphery of the ring sleeve (41), and the bottom of the bottom mold (42) is flush with the bottom of the ring sleeve (41); the annular groove (44) is constructed on the inner periphery of the bottom mold (42); the bottom plate (43) is slidably arranged in the annular groove (44), and the bottom of the bottom plate (43) is connected to the hydraulic cylinder (2); the oxide scale discharge port (45) is provided on the outer periphery of the bottom mold (42), and the oxide scale discharge port (45) is communicated with the annular groove (44); and a straight-shaped sliding groove (411) adapted to the slider (92) is provided on the surface of the ring sleeve (41).

5. The bolt forging assembly tool according to claim 4, characterized in that: The fixed mold assembly (7) further comprises an arc-shaped connecting rod (72), a limit block (73) and a gear ring (74); the inner circumference of the gear ring (74) is meshed with the driving teeth (84), and the gear ring (74) is installed between a plurality of top molds (71); the arc-shaped connecting rod (72) is installed between adjacent top molds (71); and the limit block (73) is installed on the top of the top mold (71).

6. The bolt forging assembly tool according to claim 5, characterized in that: A limiting groove (61) is provided at the bottom of the top plate (6), and the limiting groove (61) is matched with the limiting block (73).

7. The bolt forging assembly tool according to claim 2, characterized in that: A tooth groove is provided on the upper portion of the side wall of the rack (91), and the tooth groove on the rack (91) is provided on the side of the rack (91) away from the bottom mold (42).

8. The bolt forging assembly tool according to claim 4, characterized in that: The edge of the scale discharge port (45) is flush with the surface of the bottom plate (43) when it is at the lowest point, and the cross section of the bottom plate (43) is a trapezoid.

9. The bolt forging assembly tool according to claim 1, characterized in that: The side groove (10) has an isosceles trapezoidal cross section when viewed from the side, and the longer side is arranged on the side away from the push switch (96).

10. A method of use, applicable to a bolt forging assembly tool as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1. A high-speed rail brake bolt blank cut in advance to the same length is placed inside a bottom die (42) after being heated. When the hydraulic cylinder (2) is extended, the bottom plate (43) is first lifted up, and a portion of the top of the blank is exposed from the bottom die (42). When the top of the bottom plate (43) is fitted with the top of the annular groove (44), the bottom die (42), the ring sleeve (41) and the bottom plate (43) are moved upward together, and a portion of the top of the blank is exposed from the bottom die (42); S2, when the ring sleeve (41) moves upward, it drives the rack (91) to move upward, and the end of the insertion rod (93) moves along the longer side of the side groove (10). At this time, the rack (91) is at the maximum distance from the bottom mold (42) under the cooperation of the insertion rod (93) and the side groove (10). During the continuous upward movement of the rack (91), the rack (91) and the transmission tooth (82) are meshed to the separation process. After the rack (91) and the transmission tooth (82) are meshed and continue to move upward, the transmission tooth (82) rotates and drives the transmission shaft (81) to rotate. The transmission shaft (81) drives the drive shaft (83) and the drive tooth (84) to rotate through the bevel gear set. Under the cooperation of the drive tooth (84) and the gear ring (74), the fixed mold assembly (7) is driven to rotate, and the top mold (71) with mold cavities a, b, and c opened therein is rotated to the top of the bottom mold (42) in sequence; S3, before the top of the blank enters the top die (71), when the extrusion block (95) moves upward with the ring sleeve (41) through the bending rod (94) and contacts the push switch (96), the extrusion block (95) applies pressure to the push switch (96), thereby turning on the power of the electromagnetic coil (5) to compensate for the heat loss of the blank after it is placed on the bottom die (42). In the subsequent process of the extrusion block (95) continuing to move upward with the ring sleeve (41), the extrusion block (95) separates from the push switch (96), and the blank completely enters the top die (71) to complete the forging of the corresponding shape. At this time, the insertion rod (93) moves to the highest point of the side groove (10), and the upper pressing block (101) is reset after being pressed, and presses against the insertion rod (93) from below; S4, then the hydraulic cylinder (2) contracts, the ring sleeve (41), the bottom mold (42), the bottom plate (43), and the rack (91) move downward together, and the insertion rod (93) moves along the oblique side of the side groove (10) to the side of the shorter side of the side groove (10). At this time, the spacing between the rack (91), the bending rod (94) and the extrusion block (95) and the bottom mold (42) decreases. In the subsequent downward movement process, the rack (91) does not mesh with the transmission tooth (82), and the extrusion block (95) does not contact the press switch (96). When the insertion rod (93) moves to the lowest point, the end of the insertion rod (93) enters the longer side from the shorter side of the side groove (10) and squeezes the pressing block (101) below. When the insertion rod (93) moves upward, it moves along the longer side of the side groove (10); S5, after the hydraulic cylinder (2) is retracted to the initial position, it is retracted and extended twice, and the three top dies (71) all rotate one circle. The forging operation of a single high-speed rail brake bolt blank is completed, and the forged high-speed rail brake bolt is removed from the bottom die (42) for subsequent processing steps, and a new heated blank is placed in the bottom die (42).

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