WO2021238307A1

WO2021238307A1 - Precision forming die for warm forging of straight bevel gear

Info

Publication number: WO2021238307A1
Application number: PCT/CN2021/077143
Authority: WO
Inventors: 左玉成; 黄廷波; 李荫现; 龚仁春; 蒯志刚
Original assignee: 江苏飞船股份有限公司
Priority date: 2020-05-24
Filing date: 2021-02-22
Publication date: 2021-12-02
Also published as: CN111687356A

Abstract

Disclosed is a precision forming die for the warm forging of a straight bevel gear, the precision forming die comprising: a rough forging die formed by an upper gear die (1) and a lower cavity die (8) fitted with each other, and a precision forging die formed by an upper cavity die (15) and a lower gear die (21) fitted with each other, wherein the upper die of each of the rough forging die and the precision forging die is internally provided with a knockout structure composed of an elastic element to prevent a formed gear blank and a gear from adhering to the upper die; the outer circumference of the gear die of each of the rough forging die and the precision forging die is provided with a guide cylinder so as to ensure that the staggering amount of the upper die and the lower die does not exceed 0.3 mm and provide a prestressing force for the gear die, so as to prevent gear shape precision out-of-tolerance caused by deformation of the gear profile of the gear dies due to three-way pressure stress applied to the gear die; and the lower cavity die is provided with a floating die lifting structure which enables the lower cavity die to float and cooperate with a shaft neck of the lower cavity die for accurately positioning the blank, which ensures that the blank is evenly distributed in the gear shape of the gear die cavity during rough forging, reduces deformation after elimination of residual stress of the gear, and facilitates forging to form a recess structure, towards the interior of the gear blank, on the end face of the gear shape and the end face of the shaft neck of the gear blank, thereby improving the utilization rate of the blank.

Description

Warm Forging Precision Forming Die for Straight Bevel Gears

Technical field

The invention relates to the technical field of mechanical manufacturing, in particular to a warm forging precision forming die for straight bevel bevel gears.

Background technique

During the warm forging of straight bevel bevel gears on the automatic line of the electric screw press, on the one hand, due to the anisotropy of the deformed material and the mold base used for mold installation, it must be convenient for the manipulator to place and grab the material, so no guide post is usually used. Structure, it is impossible to realize that the error modulus does not exceed 0.3mm when the upper and lower molds are closed only by the accuracy and rigidity of the equipment's guide rail; Because the diameter of the inner positioning surface is usually larger than the diameter of the blank to be deformed, the blank to be deformed cannot be accurately positioned in the rough forging gear die; the existence of these two reasons causes uneven distribution of the blank to be deformed when forming the tooth blank, and after the residual stress of the gear is eliminated The deformation is large and the accuracy level is low. At the same time, when the rough forging tooth die is used as the lower die, it takes a long time to contact the high temperature tooth blank, which can easily cause the rough forging tooth die to be tempered and softened at high temperature, which greatly reduces the life of the rough forging tooth die. Generally, the service life does not exceed 3000.

In some processes, the positions of the rough forging tooth die and the rough forging cavity die are exchanged. The rough forging tooth die is used as the upper die and the rough forging cavity die is used as the lower die. The journal of the rough forging cavity die is used to accurately position the blank to be deformed. , And use a hydraulic device for punching, but due to the "hysteresis" of the hydraulic device, when the slide of the equipment returns to a certain distance above the bottom dead center, the extruded tooth blank will leave the cavity of the rough forging tooth die. The manipulator could not grab the tooth blank normally, which led to the abnormal shutdown of the automatic line of the electric screw press.

Summary of the invention

The purpose of the present invention is to provide a warm forging precision forming die for straight bevel bevel gears. The precision structure design of the forming die includes adjusting the composition of the upper and lower die, automatic punching of the upper die during forging, precise positioning of the blank, and setting of prestress and guidance. Mechanisms and other methods can significantly increase the service life of rough and fine forging dies, increase tooth profile accuracy and blank utilization rate, and effectively solve the above technical problems.

In order to achieve the above objective, the present invention proposes the following technical solutions: a straight bevel gear warm forging precision forming die, including a rough forging die and a precision forging die composed of an automatic line of an electric screw press, wherein the definition is defined as the middle die of the rough forging die The cavity parting surface is divided into a first upper mold and a first lower mold, and the cavity parting surface of the precision forging mold is divided into a second upper mold and a second lower mold;

The first upper mold includes an upper tooth mold, a first upper punching ejector pin, an upper tooth mold pressure-bearing pad, a first upper transition pad, a first upper pressure-bearing pad, a first upper punching elastic element, and The first guide tube; the lower end surface of the upper tooth mold is provided with an upper tooth model cavity with an opening facing downward, the first guide tube is sleeved on the outer circumference of the upper tooth mold, and the lower end of the first guide tube protrudes downward from the upper surface The lower end surface of the tooth mold; the first upper punching mandrel is vertically arranged in the inner hole of the upper tooth mold and the pressure bearing block of the upper tooth mold, and is supported by the pressure bearing block movably arranged on the upper tooth mold, the first The first upper transition pad in the inner hole of the upper pressure pad; the first upper transition pad is a step shaft, and the step surface of the first upper transition pad is supported on the upper end surface of the upper tooth mold pressure pad The first upper punching elastic element is vertically arranged in the inner hole of the first upper pressure-bearing pad, the lower end surface of the first upper punching elastic element abuts the upper end surface of the first upper transition pad, and the The first upper punching elastic element, the first upper transition pad and the first upper punching ejector rod form a coaxial topping structure;

The first upper punching elastic element has at least a first state and a second state in the inner hole of the first upper pressure-bearing pad; the first state is that the first upper punching elastic element supports the first upper transition pad The step surface of the upper tooth mold is against the upper end surface of the pressure-bearing block of the upper tooth mold, and the first upper punching ejector pin partially extends into the cavity of the upper tooth mold; the second state is that the first upper punching elastic element is in a compressed state, The step surface of an upper transition pad is spaced from the upper end surface of the upper tooth mold pressure-bearing pad.

The first lower mold includes a lower cavity mold, a first lower ejector rod, a floating mold lifting elastic element, a lower cavity mold pressure pad, a first lower transition pad, a first lower pressure pad and a first lower pressure pad. Lower ejector rod; the upper end surface of the lower cavity mold is provided with a concave model cavity with an opening facing upwards, the lower cavity mold is matched with the upper tooth mold, and the outer circumference of the lower cavity mold is aligned with the first guide tube The inner hole is adapted; the lower cavity mold pressure bearing block is provided with an inner hole in the center, the first lower ejector rod is vertically arranged in the lower cavity mold and the lower cavity mold pressure bearing block inner hole, the first The lower ejector rod is supported by a first lower transition block movably arranged in the inner hole of the pressure bearing block of the lower cavity mold; the first lower transition block is set as a vertical cylindrical shaft, and the lower end surface of the cylindrical shaft Supported on the upper end surface of the first lower pressure-bearing pad; the first lower ejector rod is vertically arranged in the inner hole of the first lower pressure-bearing pad, and the upper end surface of the first lower ejector rod abuts against the first lower transition On the lower end surface of the cushion block, the first lower ejector rod, the first lower transition block and the first lower ejector rod form a coaxial topping structure;

The floating mold lifting elastic element is arranged between the lower cavity mold and the first lower pressure bearing block, the upper end surface of the floating mold lifting elastic element abuts against the lower end surface of the lower cavity mold, and the lower end surface of the floating mold lifting elastic element Abuts against the upper end surface of the first lower pressure-bearing pad; the floating mold lifting elastic element has at least a first compression state and a second compression state between the lower cavity mold and the first lower pressure-bearing pad. In a compressed state, the lower end surface of the lower cavity mold supported by the floating mold lifting elastic element is spaced from the upper end surface of the pressure bearing block of the lower cavity mold, and the second compressed state is that the floating mold lifting elastic element is compressed to the lower end surface of the lower cavity mold. The upper end surface of the pressure-bearing cushion block of the lower cavity mold is resisted, and the first lower ejector rod partially extends into the lower concave mold cavity.

The second upper mold includes an upper cavity mold, a second upper punching ejector pin, an upper cavity mold pressure-bearing pad, a second upper transition pad, a second upper pressure-bearing pad and a second upper punching elastic Element; the lower end surface of the upper cavity mold is centrally provided with an open-down upper concave mold cavity, and the upper concave mold cavity part protrudes downward from the lower end surface of the upper cavity mold to form the outer circle guide of the upper cavity mold The second upper punching rod is vertically arranged in the inner hole of the upper cavity mold and the pressure bearing block of the upper cavity mold, and is supported on the upper cavity mold pressure bearing block, the second The second upper transition pad in the inner hole of the upper pressure pad; the second upper transition pad is a step shaft, and the step surface of the second upper transition pad is supported on the upper cavity mold pressure pad The end face; the second upper elastic element is vertically arranged in the inner hole of the second upper pressure-bearing pad, the lower end surface of the second upper elastic element abuts the upper end surface of the second upper transition pad, and the The second upper punching elastic element, the second upper transition block and the second upper punching ejector rod form a coaxial topping structure;

The second upper punching elastic element has at least a third state and a fourth state in the inner hole of the second upper pressure-bearing pad; the third state is that the second upper punching elastic element supports the second upper transition pad The step surface of the upper mold is in contact with the upper end surface of the pressure-bearing pad of the upper cavity mold, and the second upper punching ejector pin partially extends into the upper concave mold cavity; the fourth state is that the second upper punching elastic element is in a compressed state , The step surface of the second upper transition pad is spaced apart from the upper end surface of the pressure bearing pad of the upper cavity mold.

The second lower mold includes a lower tooth mold, a second lower ejector rod, a lower tooth mold pressure pad, a second lower transition pad, a second lower pressure pad, and a second lower ejector rod. The mold is matched with the upper cavity mold; the upper end surface of the lower tooth mold is provided with a lower tooth mold cavity with an opening facing upward, and the outer circumference of the lower tooth mold is sleeved with a second guide tube; the second guide tube The upper end surface protrudes upward from the upper end surface of the lower tooth mold, and the inner hole of the second guide cylinder is adapted to the outer circumference of the outer circular guide part of the upper cavity mold; the second lower ejector rod is vertically arranged on the lower tooth mold and the lower tooth In the inner hole of the pressure cushion block of the mold, the second lower ejector rod is supported by a second lower transition block movably arranged in the inner hole of the pressure cushion block of the lower tooth mold, and the second lower ejector rod partially extends into the lower teeth In the model cavity; the second lower transition pad is set as a vertical cylindrical shaft, the lower end of the cylindrical shaft is supported on the upper end of the second lower pressure-bearing pad; the second lower ejector rod is set vertically at In the inner hole of the second lower pressure bearing block, the upper end surface of the second lower ejector rod abuts against the lower end surface of the second lower transition pad. The second lower ejector rod, the second lower transition pad and the second lower top The output rod constitutes a coaxial phase top structure.

Further, it is defined that the height difference between the lower end surface of the first guide cylinder and the lower end surface of the upper tooth mold in the vertical direction is H1, and the height difference between the upper end surface of the second guide cylinder and the upper end surface of the lower gear mold in the vertical direction is H2, The height of the outer circular guide portion of the upper cavity mold protruding from the lower end surface of the upper cavity mold is H3, then H3=H2, H2≥23mm, H1≥40mm.

Further, the outer circular guide portion of the upper cavity mold is provided with an exhaust hole.

Further, the upper end surface of the first guide cylinder abuts against the lower end surface of the upper tooth mold pressure pad, the lower end surface of the second guide cylinder abuts against the upper end surface of the lower tooth mold pressure pad, and the first guide The interference fit of the barrel and the upper gear mold, the interference fit of the second guide barrel and the lower gear mold, the best interference coefficient is maintained at 4‰-6‰, and the material of the first guide barrel and the second guide barrel is H13 mold steel , The hardness after heat treatment is HRC44-48.

Further, the pressure bearing block of the lower cavity mold is also provided with a plurality of through holes penetrating the upper and lower end surfaces of the pressure bearing block of the lower cavity mold, and the through holes are along the inner hole of the pressure bearing block of the lower cavity mold. The circumferential ring is evenly arranged; the floating mold lifting elastic element is arranged in the through hole and is arranged as a spring.

Further, the first upper elastic element is configured as a first nitrogen spring, and the second upper elastic element is configured as a second nitrogen spring; the first upper pressure bearing block is provided with a first cooling A second cooling mechanism is arranged in the second upper pressure bearing block; the cooling mechanism is used to adjust the nitrogen gas spring to a normal operating temperature.

It can be seen from the above technical solution that the warm forging precision forming die for straight bevel gears provided by the technical solution of the present invention has obtained beneficial effects:

The warm forging precision forming die for straight bevel bevel gears disclosed by the present invention has simple structure and convenient operation. It includes a rough forging die matched by an upper tooth die and a lower cavity die and a precision forging die matched by an upper cavity die and a lower tooth die. ; During rough forging, the tooth mold is on the top, and the contact time between the high temperature blank and the tooth mold is the shortest, which basically eliminates the risk of tempering and softening of the tooth mold. The failure mode of the upper tooth mold is only normal wear and the life of the tooth mold is significantly improved. Among them, in the present invention, a punching structure composed of elastic elements is provided in the upper molds of the rough forging die and the fine forging die respectively to prevent the formed tooth blank and gear from adhering to the upper die, that is, the elastic element stores energy when the mold is closed and releases the mold. When the energy storage is used to separate the blank from the upper die, it can solve the "hysteresis" when the hydraulic device is used to punch the material; set the guide cylinder on the outer circumference of the upper tooth die of the rough forging die and the lower tooth die of the fine forging die. On the one hand, It is used to close the guide cavity mold and the tooth mold to ensure that the staggered modulus of the upper and lower molds does not exceed 0.3mm. On the other hand, the cavity mold is provided with a prestress within the covering range of the guide cylinder to avoid the tooth profile of the tooth mold. Deformation to prevent the blank from flashing when the die is closed and upset.

In the present invention, a floating mold lifting structure composed of an elastic structure is arranged on the lower die of the rough forging die, the lower cavity die is floated from the pressure bearing block of the lower cavity die, and the blank is accurately positioned with the journal of the cavity die to ensure the rough forging At the same time, the blank to be deformed is evenly distributed in the tooth profile of the tooth model cavity, which improves the accuracy of the tooth profile and reduces the deformation after the residual stress of the gear is eliminated. The lower ejector rod partially extends into the lower concave mold cavity, and cooperates with the first upper punching ejector rod to forge a recessed structure into the tooth blank on the tooth profile end face and the journal end face of the tooth blank, thereby increasing the utilization rate of the blank by 3%.

In addition, adopting the structure of providing prestress in the guide cylinder of the precision forging tooth die not only ensures that the modulus of the upper and lower dies does not exceed 0.3mm, but also avoids the tooth profile deformation of the precision forging tooth die under the state of three-way compressive stress. In order to avoid the problem of reduction of tooth profile accuracy caused by mold deformation; at the same time, vent holes are arranged on the outer guide part of the upper cavity die for precision forging, which can ensure the uniform distribution of lubricant on the tooth surface of the precision forging gear and ensure the consistency of the precision forging tooth profile. Performance, improve the life of the mold, an increase of more than 68.75%.

It should be understood that all combinations of the aforementioned concepts and the additional concepts described in more detail below can be regarded as part of the inventive subject matter of the present disclosure as long as such concepts are not mutually contradictory.

The foregoing and other aspects, embodiments and features of the teachings of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and/or beneficial effects of the exemplary embodiments, will be apparent in the following description, or learned from the practice of the specific embodiments taught in accordance with the present invention.

Description of the drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in each figure may be denoted by the same reference numeral. For clarity, not every component is labeled in every figure. Now, embodiments of various aspects of the present invention will be described by way of examples and with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of the structure of the rough forging forming die for straight bevel bevel gears;

Figure 2 is a schematic diagram of the structure of the precision forging forming die for straight bevel bevel gears;

Figure 3 is a cross-sectional view of the upper tooth mold with the first guide cylinder in Figure 1;

Figure 4 is a cross-sectional view of the first upper pressure bearing block in Figure 1;

Figure 5 is a cross-sectional view of the lower cavity mold in Figure 1;

Fig. 6 is a cross-sectional view of the pressure bearing block of the lower cavity mold in Fig. 1;

Fig. 7 is a sectional view of the first lower pressure bearing block in Fig. 1;

Figure 8 is a cross-sectional view of the upper cavity mold in Figure 2;

Figure 9 is a cross-sectional view of the second upper pressure bearing block in Figure 2;

Fig. 10 is a cross-sectional view of the lower tooth mold in Fig. 2.

In the figure, the specific meaning of each mark is:

1-Upper tooth mold, 2-First upper punching ejector pin, 3-Upper tooth mold pressure pad, 4-First upper transition pad, 5-First upper pressure pad, 6-First upper Punching elastic element, 7-first guide tube, 8-lower cavity mold, 9-first lower ejector rod, 10-floating mold lifting elastic element, 11-lower cavity mold pressure pad, 12-th Lower transition pad, 13-first lower pressure-bearing pad, 14-first lower ejector pin, 15-upper cavity mold, 16-second upper punch ejector pin, 17-upper cavity mold under pressure Cushion block, 18-second upper transition block, 19-second upper pressure-bearing block, 20-second upper punching elastic element, 21-lower tooth mold, 22-second lower ejector rod, 23-down Tooth mold pressure bearing block, 24-second lower transition block, 25-second lower pressure bearing block, 26-second lower ejector rod, 27-second guide cylinder.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by those with ordinary skills in the field to which the present invention belongs.

The "first", "second" and similar words used in the specification and claims of the patent application of the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates other circumstances, the singular form of "a", "an" or "the" and other similar words do not mean a quantitative limit, but instead mean that there is at least one. "Include" or "include" and other similar words mean that the elements or things before "include" or "include" now cover the features, wholes, steps, operations, elements and/or listed after "include" or "include". Or components, does not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components, and/or collections thereof. "Up", "Down", etc. are only used to indicate the relative position relationship. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

In the forging process of straight-tooth bevel gears based on the prior art, when the tooth die is used as the lower die for rough forging, there is a problem of inaccurate positioning of the blank, resulting in uneven distribution of the blank between the teeth when the die is closed, and low tempering and softening life of the tooth die. When used as the upper die for rough forging, there is the "hysteresis" problem of the hydraulic punching mechanism; in addition, there are a series of technical problems such as only relying on the positioning of the equipment and the guide rail cannot reach the requirement of modulus not exceeding 0.3mm during forging. The present invention aims to provide a warm forging precision forming die for straight bevel bevel gears, which has a simple structure, effectively solves the above technical problems, and improves the life of the die and the precision of forming gears as a whole.

In the following, the warm forging precision forming die for straight bevel gears of the present invention will be further described in detail with reference to the embodiments shown in the drawings.

As shown in Figure 1 and Figure 2, a straight bevel gear warm forging precision forming die includes a rough forging die and a precision forging die composed of an automatic line of an electric screw press. The definition is divided by the cavity of the rough forging die The surface is divided into a first upper mold and a first lower mold, and a second upper mold and a second lower mold are divided into a second upper mold and a second lower mold by the cavity parting surface of the precision forging mold; the first upper mold includes an upper tooth mold 1, a second The lower mold includes a lower cavity mold 8, the second upper mold includes an upper cavity mold 15, and the second lower mold includes a lower tooth mold 21. That is, the cavity mold journal is used to position the blank during rough forging. During rough forging, it mainly stays on the lower cavity mold 8, which also reduces its contact time with the upper tooth mold 1, basically eliminating the risk of the upper tooth mold 1 being susceptible to high temperature tempering and softening, and changing the failure mode of the upper tooth mold 1 from the past. The early failure form of rapid wear becomes the current normal wear failure. The life of the upper tooth mold 1 has changed from no more than 3000 in the past to far more than 10,000 in the current forming. The rough forging mold is extended. Life span is more than 200%.

In order to avoid the "hysteresis" of the upper gear die 1 using hydraulic devices on the automatic line of the electric screw press, and the existing automatic line of the electric screw press has no guide column structure, the upper and lower parts cannot be realized by only relying on the accuracy and rigidity of the equipment guide rail. For the technical problem that the modulus error does not exceed 0.3 mm when the mold is closed, the present invention improves the structure of the upper tooth mold 1 as follows. 3 and 4, the first upper mold also includes a first upper punching ejector pin 2, an upper tooth mold pressure bearing block 3, a first upper transitional block 4, a first upper pressure bearing block 5, The first upper punching elastic element 6 and the first guide cylinder 7, wherein the lower end surface of the upper tooth mold 1 is provided with an upper tooth model cavity with an opening facing downward, and the first guide cylinder 7 is sleeved on the outer circumference of the upper tooth mold 1 , And the lower end surface of the first guide cylinder 7 protrudes downward from the lower end surface of the upper tooth mold 1. The first upper punching mandrel 2 is vertically arranged in the inner holes of the upper tooth mold 1 and the upper tooth mold pressure bearing block 3, and is supported by the movably arranged upper tooth mold pressure bearing block 3, the first upper pressure bearing block 3, The first upper transition pad 4 in the inner hole of the pad 5; the first upper transition pad 4 is a step shaft, and the step surface of the first upper transition pad 4 is supported on the upper tooth mold pressure pad 3 The upper end surface; the first upper punching elastic element 6 is vertically arranged in the inner hole of the first upper pressure-bearing pad 5, and the lower end surface of the first upper punching elastic element 6 abuts against the first upper transition pad 4 The upper end surface, the first upper punching elastic element 6, the first upper transition block 4 and the first upper punching ejector rod 2 form a coaxial topping structure.

In order to ensure that the first upper punching mandrel 2 can quickly detach the tooth blank from the upper tooth mold 1 during demolding, the first upper punching elastic element 6 has at least a first in the inner hole of the first upper pressure pad 5 The state and the second state, specifically, the first state is that the stepped surface of the first upper punching elastic element 6 supporting the first upper transition block 4 abuts the upper end surface of the upper tooth mold pressure block 3, at this time, the first An upper punching mandrel 2 protrudes into the cavity of the upper tooth mold at the end portion close to the upper tooth mold 1 under the action of the first upper punching elastic element 6; the second state is that the first upper punching elastic element 6 is in compression In the state, under the action of the clamping pressure, the step surface of the first upper transition pad 4 is spaced from the upper end surface of the upper tooth mold pressure-bearing pad 3.

The upper tooth mold 1 of the present invention is initially in the first state by the action of the first upper punching elastic element 6, and is squeezed by the blank in the upper tooth mold cavity when the mold is closed, and the first upper punching ejector rod 2 passes through the first upper The transition block 4 compresses the first upper punching elastic element 6 upwards to realize the pre-loading and energy storage of the first upper punching elastic element 6; when demolding, the upper tooth mold 1 reaches the bottom dead on the slider of the electric screw press. Immediately return upward after the point, the first upper punching elastic element 6 automatically recovers deformation without hydraulic activation, and quickly releases energy storage. The first upper punching elastic element 6 pushes the first upper punching downward through the first upper transition block 4 The ejector rod 2 partially extends into the tooth model cavity of the upper tooth mold 1, and the first upper punching ejector rod 2 pushes the formed tooth blank out of the tooth model cavity, so that the tooth blank is separated from the upper tooth mold 1. The cavity mold is always left In 8, avoid the phenomenon that the tooth blank adheres to the upper tooth mold 1, causing the tooth blank to fall from the upper tooth mold 1 and be damaged.

As shown in FIGS. 5 to 7, the first lower mold also includes a first lower ejector rod 9, a floating mold lifting elastic element 10, a lower cavity mold pressure bearing block 11, a first lower transition block 12, and a first The lower pressure-bearing pad 13 and the first lower ejector rod 14, the upper end surface of the lower cavity mold 8 is provided with a lower concave mold cavity with an opening facing upwards, the lower cavity mold 8 is adapted to the upper tooth mold 1, and The outer circumference of the cavity mold 8 is matched with the inner hole of the first guide tube 7. The lower cavity mold pressure bearing block 11 is centrally provided with an inner hole, the first lower ejector rod 9 is vertically arranged in the lower cavity mold 8 and the lower cavity mold pressure bearing block 11 inner holes, the first lower ejector rod 9 and supported by the first lower transition block 12 movably arranged in the inner hole of the pressure bearing block 11 of the lower cavity mold. Wherein, the first lower transition block 12 is arranged as a vertical cylindrical shaft, and the lower end surface of the cylindrical shaft is supported on the upper end surface of the first lower pressure bearing block 13; the first lower ejector rod 14 is vertically arranged on the In the inner hole of the lower pressure bearing block 13, the upper end surface of the first lower ejector rod 14 abuts against the lower end surface of the first lower transition block 13, and the first lower ejector rod 14, the first lower transition block 12, and the first lower transition block 13 The bottom ejector rod 9 forms a coaxial phase top structure. The floating mold lifting elastic element 10 is provided in the lower cavity mold 8 to float the lower cavity mold 8 from the pressure bearing block 11 of the lower cavity mold. During rough forging, the blank is evenly distributed in the tooth profile of the upper tooth mold cavity to reduce the deformation of the gear after the residual stress is eliminated, and to improve the accuracy of the tooth profile; on the other hand, it is to improve the utilization rate of the blank during rough forging.

Specifically, the floating mold lifting elastic element 10 is arranged between the lower cavity mold 8 and the first lower pressure-bearing pad 13, and the upper end surface of the floating mold lifting elastic element 10 abuts against the lower end surface of the lower cavity mold 8. The lower end surface of the mold elastic element 10 abuts against the upper end surface of the first lower pressure bearing block 13. The floating mold lifting elastic element 10 has at least a first compressed state and a second compressed state between the lower cavity mold 8 and the first lower pressure-bearing pad 13, the first compressed state is that the floating mold lifting elastic element 10 supports the lower cavity mold 8 The lower end surface is spaced from the upper end surface of the lower cavity mold pressure bearing block 11, that is, floating above the lower cavity mold pressure bearing block 11; the second compression state is that the floating mold lifting elastic element 10 is compressed to the lower cavity mold The lower end surface of 8 abuts against the upper end surface of the pressure-bearing pad 11 of the lower cavity mold, and the first lower ejector rod 9 partially extends into the lower concave mold cavity. When the mold is closed, the floating mold lifting elastic element 10 is compressed under the pressure of the upper tooth mold 1, the floating mold lifting elastic element 10 is in the second compressed state, and the first lower ejector rod 9 is close to the first upper The end of the mold is in contact with the blank in the concave mold cavity, and a recessed structure is forged into the tooth blank on the journal end surface of the tooth blank during forming.

At the same time, in the upper tooth mold 1, when the first upper punching elastic element 6 is in the second state when the mold is closed, the end of the first upper punching mandrel 2 close to the first lower mold also partially extends into the upper tooth model The cavity is in contact with the blank, and a recessed structure toward the inside of the tooth blank is forged on the tooth-shaped end surface of the formed tooth blank. The recessed structure at both ends of the tooth blank can significantly increase the material utilization rate by 3% on the basis of the existing blank utilization rate.

During rough forging, because the first guide cylinder 7 is provided on the outer circumference of the upper tooth mold 1, the lower cavity mold 8 can be accurately guided when the mold is closed to ensure that the central axes of the upper tooth mold 1 and the lower cavity mold 8 coincide. The modulus error between the upper and lower molds is controlled within 0.3mm, and the upper tooth mold 1 is provided with prestress at the same time to prevent the upper tooth mold 1 from being subjected to three-directional compressive stress to cause the tooth profile to be deformed. Poor and flash issues.

As shown in FIG. 8 and FIG. 9, the second upper mold also includes a second upper punching ejector pin 16, an upper cavity mold pressure bearing block 17, a second upper transition block 18, and a second upper pressure bearing block 19 And the second upper punching elastic element 20, wherein the lower end surface of the upper cavity mold 15 is centrally provided with an upper concave mold cavity with an opening facing downward, and the upper concave mold cavity partly protrudes downward from the lower end surface of the upper cavity mold 15 The outer circle guide part of the upper cavity mold is formed. The second upper punching mandrel 16 is vertically arranged in the inner holes of the upper cavity mold 15 and the upper cavity mold pressure bearing block 17, and is supported by the pressure bearing block 17 and the second cavity movably arranged on the upper cavity mold. On the second upper transition pad 18 in the inner hole of the upper pressure-bearing pad 19; the second upper transition pad 18 is a stepped shaft, and the step surface of the second upper transition pad 18 is supported on the upper cavity mold bearing The upper end surface of the cushion block 17 is pressed. The second upper elastic element 20 is vertically arranged in the inner hole of the second upper pressure bearing block 19, and the lower end surface of the second upper elastic element 20 abuts against the upper end surface of the second upper transition block 18, And the second upper punching elastic element 20, the second upper transition block 18 and the second upper punching jack 16 form a coaxial topping structure.

In order to ensure that the second upper punching mandrel 16 can quickly detach the formed gear from the upper cavity mold 15 when demolding, the second upper punching elastic element 20 has at least in the inner hole of the second upper pressure pad 19 The third state and the fourth state; specifically including, the third state is that the stepped surface of the second upper punching elastic element 20 supporting the second upper transition pad 18 abuts the upper end surface of the upper cavity mold pressure-bearing pad 17, and The second upper punching mandrel 16 partially extends into the upper concave mold cavity; the fourth state is that the second upper punching elastic element 20 is in a compressed state, and the step surface of the second upper transition block 18 is spaced from the upper cavity mold bearing The upper end surface of the cushion block 17 is pressed.

Similar to the rough forging and punching process, at the beginning, the second upper punching elastic element 20 acts in the third state. When the mold is closed, it is squeezed by the blank in the upper concave mold cavity, and the second upper punching pin 16 passes through the second upper The transition block 18 compresses the second upper elastic element 20 upwards to realize the pre-loading and energy storage of the second upper elastic element 20; during demolding, the upper cavity mold 15 reaches the bottom of the slider of the electric screw press. Immediately after the dead center, the second upper elastic element 20 automatically recovers deformation without hydraulic activation, and quickly releases the energy storage. The second upper elastic element 20 pushes down through the second upper transition block 18 and the second upper striker. The material ejector rod 16 partially extends into the upper concave mold cavity, and the second upper material ejector rod 16 pushes out the gear obtained by the precision forging, and is separated from the upper cavity mold 15.

As shown in FIG. 10, the second lower mold also includes a second lower ejector rod 22, a lower tooth mold pressure bearing block 23, a second lower transition block 24, a second lower pressure bearing block 25, and a second lower top The material rod 26, wherein the lower tooth mold 21 is adapted to the upper cavity mold 15, the upper end surface of the lower tooth mold 21 is provided with a lower tooth mold cavity with an opening facing upward, and the outer circumference of the lower tooth mold 21 is sleeved with a first Two guide cylinders 27; the upper end of the second guide cylinder 27 protrudes upward from the upper end surface of the lower tooth mold 21, and the inner hole of the second guide cylinder 27 fits with the outer circumference of the outer circular guide portion of the upper cavity mold. The second lower ejector rod 22 is vertically arranged in the inner hole of the lower tooth mold 21 and the pressure bearing block 23 of the lower tooth mold, and the second lower ejection rod 22 is movably arranged in the inner hole of the lower tooth mold pressure pad 23 The second lower transition block 24 is supported, and the second lower ejector rod 22 partially extends into the lower tooth model cavity; the second lower transition block 24 is set as a vertical cylindrical shaft, and the lower end surface of the cylindrical shaft supports On the upper end surface of the second lower pressure bearing block 25. The second lower ejector rod 26 is vertically arranged in the inner hole of the second lower pressure bearing block 25, the upper end surface of the second lower ejector rod 26 abuts against the lower end surface of the second lower transition pad 24, and the second lower ejector The rod 26, the second lower transition block 24 and the second lower ejector rod 22 form a coaxial topping structure.

In the precision forging, the second guide cylinder 27 achieves the same technical effect as the rough forging, guiding and providing prestress. Specifically, the second guide cylinder 27 on the outer circumference of the lower tooth mold 21 is aligned with the outer circumference of the upper cavity mold when the mold is closed. The guide parts are matched to accurately guide the upper cavity mold 15 to ensure that the central axes of the upper cavity mold 15 and the lower tooth mold 21 coincide, and the modulus of the precision forging upper and lower molds is controlled within 0.3mm, while correcting The lower tooth mold 21 provides prestress to avoid the reduction of tooth profile accuracy caused by the deformation of the tooth profile of the tooth mold under the three-directional compressive stress state, and reduce the loss of the tooth mold. In the embodiment, in order to improve the consistency of the tooth profile accuracy during the fine forging and increase the life of the fine forging die, vent holes are arranged on the outer guide part of the upper cavity mold to ensure that the lubricant is evenly distributed on the tooth surface of the upper tooth mold cavity Distribution, the life of precision forging die has increased by more than 68.75%.

In the embodiment, in order to ensure that the first guide tube 7 and the second guide tube 27 have sufficient rigidity to guide the cavity mold and provide prestress, the first guide tube 7 and the second guide tube 27 select H13 with a hardness of HRC44-HRC48 Made of die steel, and the upper end surface of the first guide cylinder 7 abuts against the lower end surface of the upper tooth mold pressure pad 3, and the lower end surface of the second guide cylinder 27 abuts against the upper end surface of the lower tooth mold pressure pad 23 , The first guide cylinder 7 and the upper tooth mold 1 have an interference fit, and the second guide cylinder 27 and the lower tooth mold 21 have an interference fit, and it is best to keep the interference coefficient at 4‰-6‰. At the same time, in order to ensure the implementation effect of the first guide tube 7 and the second guide tube 27, the height difference between the lower end surface of the first guide tube 7 and the lower end surface of the upper tooth mold 1 in the vertical direction is defined as H1, and the second guide tube 27 The height difference between the upper end surface and the upper end surface of the lower tooth mold 21 in the vertical direction is H2, and the height of the outer circular guide portion of the upper cavity mold protruding from the lower end surface of the upper cavity mold 15 is H3, then H3=H2, H2≥23mm , H1≥40mm; For example, when the lower cavity mold 8 is not in contact with the blank in the upper tooth mold 1, more than 5mm of the entire outer circumference has entered the inside of the first guide cylinder 7.

In further combination with the embodiment shown in FIG. 1, the lower cavity mold pressure bearing block 11 is also provided with a plurality of through holes that penetrate the upper and lower end surfaces of the lower cavity mold pressure bearing block 11, and the through holes extend along the lower cavity mold bearing block 11. The circumference of the inner hole of the pressure pad is evenly arranged, and the floating mold lifting elastic element 10 is arranged in the through hole and is arranged as a spring. In the embodiment shown in the figure, there are 4 through holes arranged in the inner circle of the pressure pad of the lower cavity mold, and the spring is a rectangular spring, the model is SG25X12.5X125, and the 4 rectangular springs are a combination and evenly distributed in the through hole. In the hole, the preset compression stroke of the rectangular spring is 10mm, that is, the floating height of the lower cavity mold 8 on the upper end surface of the pressure bearing block 11 of the lower cavity mold does not exceed 10mm.

In order to reduce the axial space occupied by arranging the upper punching elastic element in the upper mold, the first upper punching elastic element 6 is set as the first nitrogen gas spring, and the second upper punching elastic element 20 is set as the second nitrogen gas spring. The spring models are all U4700-16. At the same time, because nitrogen gas springs have higher requirements for the use environment temperature, the normal use temperature of the gas spring is within the range of 0℃-40℃, otherwise it will cause the early failure of the gas spring seals, reduce the normal service life of the gas spring, and affect the production of automatic lines Therefore, in order to ensure the stability of the working environment temperature of the nitrogen gas spring, in the embodiment, a first cooling mechanism is provided in the first upper pressure bearing block 5, and a second cooling mechanism is provided in the second upper pressure bearing block 19, Adjust the nitrogen gas spring to the normal operating temperature, as shown in Figure 4 and Figure 9. The cooling mechanism can be realized by a combination of a temperature measuring thermocouple and a cooling circulation channel, for example, setting the lower limit temperature of the temperature measuring thermocouple to 10°C and the upper limit temperature of 30°C, and transmit the signal to the control center PLC through the temperature measuring thermocouple, and the PLC command The switch passes compressed air into the cooling circulation channel to ensure that the nitrogen gas spring works within the specified ambient temperature.

The straight bevel gear warm forging precision forming die of the present invention adopts the methods of adjusting die composition, automatic punching of the upper die, precise positioning of the blank and setting of the prestressed guide mechanism to change the damage form of the rough and fine forging die into normal wear failure. Significantly improve the service life of rough and fine forging dies, and improve the accuracy of tooth profile and the utilization rate of blanks.

Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to what is defined in the claims.

Claims

A warm forging precision forming die for straight bevel bevel gears, including a rough forging die and a fine forging die composed of an automatic line of an electric screw press, wherein the definition is divided into a first upper die and a first upper die and a precision forging die based on the parting surface of the cavity in the rough forging die The first lower mold is divided into a second upper mold and a second lower mold by the parting surface of the mold cavity in the precision forging mold; characterized in that, the first upper mold includes an upper tooth mold and a first upper punching ejector pin , The upper tooth mold pressure bearing block, the first upper transition block, the first upper pressure bearing block, the first upper punching elastic element and the first guide tube;

The lower end surface of the upper tooth mold is provided with an upper tooth model cavity with an opening facing downward, the first guide cylinder is sleeved on the outer circumference of the upper tooth mold, and the lower end of the first guide cylinder protrudes downward from the lower end surface of the upper tooth mold; The first upper punching ejector rod is vertically arranged in the inner holes of the upper tooth mold and the pressure bearing block of the upper tooth mold, and is supported by the pressure bearing block and the first upper pressure bearing block movably arranged on the upper tooth mold The first upper transition pad in the inner hole; the first upper transition pad is a step shaft, and the step surface of the first upper transition pad is supported on the upper end surface of the upper tooth mold pressure pad; the first The upper punching elastic element is vertically arranged in the inner hole of the first upper pressure bearing block, the lower end surface of the first upper punching elastic element abuts the upper end surface of the first upper transition pad, and the first upper punching The elastic element, the first upper transition pad and the first upper punching ejector rod form a coaxial topping structure;

The first upper punching elastic element has at least a first state and a second state in the inner hole of the first upper pressure-bearing pad; the first state is that the first upper punching elastic element supports the first upper transition pad The step surface of the upper tooth mold is against the upper end surface of the pressure-bearing block of the upper tooth mold, and the first upper punching ejector pin partially extends into the cavity of the upper tooth mold; the second state is that the first upper punching elastic element is in a compressed state, The step surface of the upper transition block is spaced from the upper end surface of the pressure bearing block of the upper tooth mold;

The first lower mold includes a lower cavity mold, a first lower ejector rod, a floating mold lifting elastic element, a lower cavity mold pressure pad, a first lower transition pad, a first lower pressure pad and a first lower pressure pad. Click the ejector rod;

The upper end surface of the lower cavity mold is provided with a lower concave mold cavity with an opening facing upwards, the lower cavity mold is adapted to the upper tooth mold, and the outer circumference of the lower cavity mold is adapted to the inner hole of the first guide cylinder; The lower cavity mold pressure bearing block is centrally provided with an inner hole, the first lower ejector rod is vertically arranged in the lower cavity mold and the lower cavity mold pressure bearing block inner hole, and the first lower ejector rod is parallel to Supported by a first lower transition block movably arranged in the inner hole of the pressure bearing block of the lower cavity mold; the first lower transition block is set as a vertical cylindrical shaft, and the lower end surface of the cylindrical shaft is supported on the first lower The upper end surface of the pressure-bearing pad; the first lower ejector rod is vertically arranged in the inner hole of the first lower pressure-bearing pad, the upper end surface of the first lower ejector rod abuts against the lower end surface of the first lower transition pad, so The first lower ejector rod, the first lower transition block and the first lower ejector rod form a coaxial topping structure;

The floating mold lifting elastic element is arranged between the lower cavity mold and the first lower pressure bearing block, the upper end surface of the floating mold lifting elastic element abuts against the lower end surface of the lower cavity mold, and the lower end surface of the floating mold lifting elastic element Abuts against the upper end surface of the first lower pressure-bearing pad; the floating mold lifting elastic element has at least a first compression state and a second compression state between the lower cavity mold and the first lower pressure-bearing pad. In a compressed state, the lower end surface of the lower cavity mold supported by the floating mold lifting elastic element is spaced from the upper end surface of the pressure bearing block of the lower cavity mold, and the second compressed state is that the floating mold lifting elastic element is compressed to the lower end surface of the lower cavity mold. It interferes with the upper end surface of the pressure bearing block of the lower cavity mold, and the first lower ejector rod partially extends into the lower cavity of the cavity;

The second upper mold includes an upper cavity mold, the second lower mold includes a lower tooth mold, and the lower tooth mold is adapted to the upper cavity mold.
The straight bevel gear warm forging precision forming die of claim 1, wherein the height difference between the lower end surface of the first guide cylinder and the lower end surface of the upper tooth mold is defined as H1, and then H1≥40mm.
The straight bevel gear warm forging precision forming die according to claim 1, wherein the second upper die further includes a second upper punching mandrel, an upper cavity mold pressure bearing block, and a second upper transition The cushion block, the second upper pressure-bearing cushion block and the second upper punching elastic element;

The lower end surface of the upper cavity mold is centrally provided with an upper concave mold cavity with an opening facing downward, and the upper concave mold cavity part protrudes downward from the lower end surface of the upper cavity mold to form an outer circular guide portion of the upper cavity mold; The second upper punching ejector rod is vertically arranged in the inner holes of the upper cavity mold and the pressure bearing block of the upper cavity mold, and is supported by the pressure bearing block and the second upper bearing block movably arranged on the upper cavity mold. The second upper transition pad in the inner hole of the pressure pad; the second upper transition pad is a step shaft, and the step surface of the second upper transition pad is supported on the upper end surface of the upper cavity mold pressure pad; The second upper elastic element is vertically arranged in the inner hole of the second upper pressure bearing block, the lower end surface of the second upper elastic element abuts against the upper end surface of the second upper transition block, and the first The second upper punching elastic element, the second upper transition block and the second upper punching ejector rod form a coaxial topping structure;

The second upper punching elastic element has at least a third state and a fourth state in the inner hole of the second upper pressure-bearing pad; the third state is that the second upper punching elastic element supports the second upper transition pad The step surface of the upper mold is in contact with the upper end surface of the pressure-bearing pad of the upper cavity mold, and the second upper punching ejector pin partially extends into the upper concave mold cavity; the fourth state is that the second upper punching elastic element is in a compressed state , The step surface of the second upper transition pad is spaced apart from the upper end surface of the pressure-bearing pad of the upper cavity mold;

The second lower mold also includes a second lower ejector rod, a lower tooth mold pressure pad, a second lower transition pad, a second lower pressure pad, and a second lower ejector rod; the lower tooth mold The upper end surface of the lower tooth mold cavity is provided with an open mouth upward, and the outer circumference of the lower tooth mold is sleeved with a second guide cylinder; The inner hole of the guide cylinder is adapted to the outer circumference of the outer circular guide part of the upper cavity mold; the second lower ejector rod is vertically arranged in the inner hole of the lower tooth mold and the pressure bearing block of the lower tooth mold, and the second lower ejector rod It is supported by a second lower transition block movably arranged in the inner hole of the pressure bearing block of the lower tooth mold, and the second lower ejector rod partially extends into the cavity of the lower tooth model; the second lower transition block is set to be vertical A straight cylindrical shaft, the lower end surface of the cylindrical shaft is supported on the upper end surface of the second lower pressure bearing block; the second lower ejector rod is vertically arranged in the inner hole of the second lower pressure bearing block, and the second lower top The upper end surface of the material rod abuts against the lower end surface of the second lower transition pad, and the second lower ejector rod, the second lower transition pad and the second lower ejector rod form a coaxial topping structure.
The spur bevel gear warm forging precision forming die according to claim 3, wherein the height difference between the upper end surface of the second guide cylinder and the upper end surface of the lower gear mold is defined as H2, and the upper cavity mold The height of the circular guide protruding from the lower end surface of the upper cavity mold is H3, then H3=H2, H3≥23mm.
The warm forging precision forming die for straight bevel bevel gears according to claim 3, wherein the outer circular guide portion of the upper cavity die is provided with an exhaust hole.
The spur bevel gear warm forging precision forming die according to claim 3, wherein the upper end surface of the first guide cylinder abuts against the lower end surface of the upper tooth die pressure pad, and the second guide cylinder The lower end surface abuts against the upper end surface of the pressure bearing block of the lower tooth mold, and the first guide cylinder is in interference fit with the upper tooth mold, and the second guide cylinder is in interference fit with the lower tooth mold.
The spur bevel gear warm forging precision forming die according to claim 1, wherein the lower cavity mold pressure bearing block is also provided with a plurality of penetrating through the upper and lower end faces of the lower cavity mold pressure bearing block Through holes, the through holes are evenly arranged along the circumference of the inner hole of the pressure bearing block of the lower cavity mold; the floating mold lifting elastic element is arranged in the through hole and is arranged as a spring.
The spur bevel gear warm forging precision forming die according to claim 6, wherein the material of the first guide cylinder and the second guide cylinder is H13 die steel.
The warm forging precision forming die for straight bevel bevel gears according to claim 3, wherein the first upper elastic element is set as a first nitrogen spring, and the second upper elastic element is set as a second Nitrogen gas spring.
The spur bevel gear warm forging precision forming die according to claim 9, wherein a first cooling mechanism is provided in the first upper pressure bearing block, and a first cooling mechanism is provided in the second upper pressure bearing block. The second cooling mechanism.