CN105328097B - The method that helix cylindrical gear floating die assembly structure is determined based on speed difference - Google Patents

Abstract

The invention discloses a method for determining the structure of a floating die of a helical cylindrical gear based on a speed difference. The cavity height of the mold, the height of the upper punch, the height of the lower punch, the angle of rotation of the lower punch around the central axis, and the rotational angular velocity of the lower punch; the three-dimensional geometric model of the die is established in the UG software, and the three-dimensional geometric model of the die is established in the UG software. Establish the 3D geometric models of the upper punch, lower punch and blank; assemble the established 3D geometric models of the die, upper punch, lower punch and blank; import the assembled 3D geometric model into DEFORM‑3D finite element in the software. The method proposed by the invention is convenient for quickly establishing the three-dimensional finite element models of the upper punch and the concave die at different axial movement speeds, and convenient for designing the mold dimensions and processing parameters of the floating mold of the spiral cylindrical gear.

Description

Method of Determining Floating Die Structure of Helical Cylindrical Gear Based on Speed Difference

technical field

The invention relates to the technical field of forging, in particular to a method for determining the floating die structure of a helical cylindrical gear based on a speed difference.

Background technique

Helical cylindrical gears are widely used due to their many advantages such as smooth transmission, low noise, and strong load-carrying capacity. At present, helical cylindrical gears are still mostly machined, but traditional machining methods have low material utilization, high production costs, and long production cycles, and the streamline of the blank is destroyed by machining, which greatly reduces the mechanical properties of the gear. With the rapid development of science and technology, traditional machining technology and ordinary forging forming technology have long been unable to meet the needs of development. Therefore, precision forming technology must be the development direction of plastic forming technology.

When the helical cylindrical gear is precisely formed, due to its helical tooth shape and complex shape, there are problems such as large forming force, difficulty in corner filling, and difficulty in demoulding. In traditional closed forging, the upper punch goes down, the die and the lower punch are stationary, and the die moves upward relative to the billet, which generates upward friction and hinders the flow of the billet. When the floating die is used, the die moves downward relative to the blank, which generates an "effective friction force" in the downward direction, which makes the billet flow downward, which is beneficial to the filling of the lower tooth shape, and can effectively reduce the forming force to improve Die life.

However, when using the floating die to form the spiral cylindrical gear, due to the relative movement of the upper punch, die and blank, in order to ensure the coordination of the movement of the upper punch, die, lower punch and forming blank, when the set concave When the axial movement speed difference between the mold and the upper punch changes or the reduction of the formed part changes, the height of the corresponding designed upper punch, die, lower punch and the corresponding rotation angle will also change accordingly. Therefore, when forming the helical cylindrical gear with the floating die whose axial movement speed difference between the die and the upper punch is inconsistent, it is necessary to repeatedly calculate the structural height of each die and establish a three-dimensional model of the die, which affects the timely execution of the follow-up finite element analysis. .

Contents of the invention

The main purpose of the present invention is to provide a method for determining the structure of the floating mold of the helical cylindrical gear based on the speed difference, which aims to facilitate the design of the dimensions and processing parameters of the molds of the floating mold of the helical cylindrical gear under the premise of avoiding the interference of each mold.

In order to achieve the above object, the present invention provides a method for determining the floating mold structure of the helical cylindrical gear based on the speed difference, comprising the following steps:

According to the size of the helical cylindrical gear to be formed, its three-dimensional geometric model is established in UG software;

Determine the forging size and blank size according to the size of the helical cylindrical gear part to be formed, and calculate the forming pressure according to the forging size and blank size. After setting the axial speed of the upper punch and die, according to the upper punch and die The axial speed of the mold and the amount of forming pressure determine the cavity height of the die, the height of the upper punch, the height of the lower punch, the angle of rotation of the lower punch around the central axis, and the rotational angular velocity of the lower punch;

According to the size of the helical cylindrical gear part to be formed and the determined cavity height of the die, use its Boolean operation function in UG software to establish a three-dimensional geometric model of the die, and according to the size of the helical cylindrical gear part to be formed, determine the cavity height The height of the upper punch, the height of the lower punch and the size of the blank are respectively established in the UG software to establish the three-dimensional geometric models of the upper punch, the lower punch and the blank;

Assemble the three-dimensional geometric model of the concave die, upper punch, lower punch and blank established in the UG software according to the amount of forming pressure and the angle rotated by the lower punch around the central axis;

Import the three-dimensional geometric models of the assembled die, upper punch, lower punch and blank in the UG software into the DEFORM-3D finite element software, establish a three-dimensional finite element model for precision forming of the floating die of the spiral cylindrical gear, and input the above The axial speed of the punch and die, the rotation angle of the lower punch around the central axis, the rotational angular velocity of the lower punch, and the amount of forming pressure simulate the forming process to ensure that there is no interference between the molds.

Preferably, the forging size and blank size are determined according to the size of the helical cylindrical gear part to be formed, and the process of calculating the forming press-down amount according to the forging size and blank size is as follows:

Determine its forging size according to the size of the helical cylindrical gear part to be formed, calculate its part volume in UG software according to the size of the helical cylindrical gear part to be formed, and determine the blank size according to the forging size and part volume, according to the blank size and The size of the forging is calculated by the following formula:

L=hh ₁ , wherein, L is the forming depression, h ₁ is the height of the forging, and h is the height of the blank.

Preferably, after setting the axial speed of the upper punch and the die, determine the height of the cavity, the height of the upper punch, and the height of the lower punch according to the axial speed of the upper punch and the die and the amount of pressing force. , The angle of rotation of the lower punch around the central axis and the specific process of the rotation angular velocity of the lower punch are as follows:

When the axial speed of the upper punch is v _, the axial speed of the die is v _concave = bv _, when b is a constant, the cavity height H of the die is _concave , the height of the upper punch H is the height of _{the upper} and lower punches The angle α of the rotation of the _lower and lower punches around the central axis and the rotational angular velocity ω of the lower punch are calculated by the following formula:

ΔH=Δv×t, Δv=(v _concave -v _up ), t=L/min(v _up , v _concave );

When Δv is zero, H _concave =h+l, H _up =h ₁ +l, H _down =L+l;

When Δv is positive, H _concave =h+ΔH+l, H _up =L+l, H _down =L+ΔH+l;

When Δv is negative, H _concave =h+l, H _up =L+|ΔH|+l, H _down =L+l;

α=180Ltan(β _b )/(πr _b );

ω=α/t;

Among them, ΔH is the height difference between the lower end surface of the upper punch and the upper end surface of the die, Δv is the axial speed difference between the die and the upper punch, t is the time for forming the spiral cylindrical gear, l is the machining allowance and Assembly margin, β _b = arctan(tan(β)cos(α _t )), t=L/min(v _up , v _concave ), β _b is the base circle helix angle, β is the gear helix angle, α _t is The pressure angle of the end face of the gear indexing circle, r _b is the radius of the base circle.

Preferably, when setting the axial speed of the upper punch and the die, according to the parameter selection of the press corresponding to the floating die of the spiral cylindrical gear, after the press is selected, the axial speeds of the upper punch and the die are selected within the working stroke speed range of the press.

Preferably, according to the size of the helical cylindrical gear part to be formed, the height of the upper punch, the height of the lower punch and the size of the blank, the specific process of establishing the three-dimensional geometric model of the upper punch, the lower punch and the blank in the UG software is as follows:

According to the size of the helical cylindrical gear part to be formed and the height of the upper punch, the three-dimensional geometric model of the upper punch is established in the UG software. The upper punch is a helical cylindrical tooth-shaped punch. Punch height Establish the three-dimensional geometric model of the lower punch in the UG software. The lower punch is a helical cylindrical tooth-shaped punch. According to the size of the helical cylindrical gear part and the blank size to be formed, the three-dimensional geometric model of the blank is established in the UG software. .

The method for determining the structure of the floating die of the spiral cylindrical gear based on the speed difference proposed by the present invention uses the principle of the floating die and the meshing principle of the spiral cylindrical gear to quickly design the three-dimensional die structure of the floating die for the precision forming of the spiral cylindrical gear based on the UG three-dimensional software. The element software analysis provides a geometric data model, which facilitates the rapid establishment of the three-dimensional finite element model of the upper punch and the die at different axial movement speeds, which saves the time of repeated modeling and avoids the interference of each mold. Using the floating die precision forming spiral cylindrical gear forming quality prediction efficiency when the speed difference between the upper punch and the die is different, it is convenient to design the mold size and processing parameters of the floating die for the spiral cylindrical gear, which is the basis for the precision forming process of the floating die for the spiral cylindrical gear Make sure to provide a basis.

Description of drawings

Fig. 1 is the flow schematic diagram of the preferred embodiment of the method for determining the structure of the floating die of the helical cylindrical gear based on the speed difference of the present invention;

Fig. 2 is the schematic diagram of the cogging geometric model of the helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

Fig. 3 is a schematic diagram of a three-dimensional model of a single tooth groove of a helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

Fig. 4 is the schematic diagram of the three-dimensional geometric model of the helical cylindrical gear in the method for determining the structure of the floating mold of the helical cylindrical gear based on the speed difference in the present invention;

Fig. 5 is a part diagram of the helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

6 is a schematic diagram of the movement principle of the floating die of the helical cylindrical gear in the method for determining the structure of the floating die of the helical cylindrical gear based on the speed difference in the present invention;

7 is a schematic diagram of the principle at the end of the forming of the helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

Fig. 8 is a schematic diagram of the three-dimensional geometric model of the lower punch of the helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

9 is a schematic diagram of the three-dimensional geometric model of the concave die of the helical cylindrical gear in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

Fig. 10 is a schematic diagram of assembling the structure of the floating die in the method for determining the structure of the floating die of the helical cylindrical gear based on the speed difference in the present invention;

11 is a schematic diagram of a three-dimensional geometric model of a helical cylindrical gear formed when the molds interfere in the method for determining the floating mold structure of the helical cylindrical gear based on the speed difference in the present invention;

12 is a schematic diagram of a three-dimensional geometric model of the floating die structure of the helical cylindrical gear in the method for determining the structure of the floating die of the helical cylindrical gear based on the speed difference in the present invention.

Among the figure: 1-upper punch, 2-die, 3-lower punch, 4-blank.

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

detailed description

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Referring to FIG. 1 , FIG. 1 is a schematic flowchart of a preferred embodiment of a method for determining the structure of a floating die of a helical cylindrical gear based on a speed difference in the present invention.

In this preferred embodiment, a method for determining the floating mold structure of the helical cylindrical gear based on the speed difference comprises the following steps:

Step S10, establishing its three-dimensional geometric model in UG software according to the size of the helical cylindrical gear part to be formed;

The specific steps to establish the three-dimensional geometric model of the helical cylindrical gear part to be formed are as follows:

1. According to the basic parameters of the helical cylindrical gear, enter the corresponding expression in the UG software;

2. Use UG software to draw an involute curve, and draw a complete end face involute tooth groove profile curve according to the structural characteristics of the helical gear;

3. During the sweeping process, multiple helical lines are used as the guiding lines of the alveolar sweeping path, and multiple planes are evenly inserted between the upper and lower end faces, and the alveolar contour curve is projected on it as the sweeping curve, and the sweeping out Complete cogging improves the accuracy of gear modeling;

4. Perform Boolean difference operation on the generated single tooth groove and tooth root cylinder, and then use the array to generate the helical cylindrical gear entity.

Step S20, determine the forging size and blank size according to the size of the helical cylindrical gear part to be formed, and calculate the forming downforce according to the forging size and blank size, and set the axial speed of the upper punch 1 and the die 2, according to The axial speed of the upper punch 1 and the die 2 and the amount of forming pressure determine the cavity height of the die 2, the height of the upper punch 1, the height of the lower punch 3, the angle at which the lower punch 3 rotates around the central axis, and The angular velocity of rotation of the lower punch 3;

The size of the forging is the size in the forging drawing corresponding to the helical cylindrical gear part. Specifically, in step S20, the forging size and the blank size are determined according to the size of the helical cylindrical gear part to be formed, and the process of calculating the forming depression according to the forging size and the blank size is as follows:

Determine its forging size according to the size of the helical cylindrical gear part to be formed, calculate its part volume in UG software according to the size of the helical cylindrical gear part to be formed, and determine the blank size according to the forging size and part volume, according to the blank size and The size of the forging is calculated by the following formula:

L=hh ₁ , wherein, L is the forming depression, h ₁ is the height of the forging, and h is the height of the blank 4 .

In step S20, after setting the axial speed of the upper punch 1 and the die 2, determine the cavity height of the die 2, the upper punch The specific process of the height of mold 1, the height of lower punch 3, the angle of rotation of lower punch 3 around the central axis, and the rotational angular velocity of lower punch 3 is as follows:

When the axial velocity of the _upper punch 1 is vup, the axial velocity of the die 2 is _vconca =bvup _, and b is a constant, the cavity height H of the die 2 is _concave , and the height of the _upper punch 1 is Hup, The height H _of the lower punch 3, the angle rotated by the lower punch 3 around the central axis and the rotational angular velocity ω of the lower punch 3 are calculated by the following formula:

ΔH=Δv×t, Δv=(v _concave -v _up ), t=L/min(v _up , v _concave );

When Δv is zero, H _concave =h+l, H _up =h ₁ +l, H _down =L+l;

When Δv is positive, H _concave =h+ΔH+l, H _up =L+l, H _down =L+ΔH+l;

When Δv is negative, H _concave =h+l, H _up =L+|ΔH|+l, H _down =L+l;

α=180Ltan(β _b )/(πr _b );

ω=α/t;

Among them, ΔH is the height difference between the lower end surface of the upper punch 1 and the upper end surface of the die 2, Δv is the axial speed difference between the die 2 and the upper punch 1, t is the time for forming the spiral cylindrical gear, l is the mechanical Machining allowance and assembly allowance, β _b =arctan(tan(β)cos(α _t )), t=L/min(v _up , v _concave ), β _b is the base circle helix angle, β is the gear helix angle , α _t is the pressure angle of the end surface of the gear indexing circle, r _b is the radius of the base circle.

When setting the axial speed of the upper punch 1 and the die 2 (that is, v _up and v _concave ), according to the parameter selection of the press corresponding to the floating die of the spiral cylindrical gear, after the press is selected, the upper punch 1 and the die The axial speed of 2 is within the working stroke speed range of the selected press.

Step S30, according to the size of the helical cylindrical gear part to be formed and the determined cavity height of the die 2, use its Boolean operation function in the UG software to establish a three-dimensional geometric model of the die 2, and according to the helical cylindrical gear part to be formed The size, the determined height of the upper punch 1, the height of the lower punch 3 and the size of the blank are respectively established in the UG software to establish the three-dimensional geometric models of the upper punch 1, the lower punch 3 and the blank 4;

In step S30, the three-dimensional geometry of the upper punch 1, the lower punch 3, and the blank 4 are respectively established in the UG software according to the size of the helical cylindrical gear part to be formed, the height of the upper punch 1, the height of the lower punch 3, and the size of the blank. The specific process of the model is as follows:

According to the size of the helical cylindrical gear part to be formed and the height of the upper punch 1, the three-dimensional geometric model of the upper punch 1 is established in the UG software. The upper punch 1 is a helical cylindrical tooth-shaped punch. The size and height of the lower punch 3 are established in the UG software to establish the three-dimensional geometric model of the upper punch 1, and the lower punch 3 is a helical cylindrical tooth-shaped punch. According to the size of the helical cylindrical gear to be formed and the blank size A three-dimensional geometric model of blank 4 is established.

Step S40, assembling the three-dimensional geometric models of the die 2, the upper die 1, the lower die 3 and the blank 4 established in the UG software according to the forming pressing force and the angle rotated by the lower punch 3 around the central axis ;

Step S50, import the three-dimensional geometric models of die 2, upper punch 1, lower punch 3 and blank 4 assembled in the UG software into DEFORM-3D finite element software, and establish a three-dimensional finite element precision forming method for the floating die of the spiral cylindrical gear. Meta-model and input the axial speed of upper punch 1 and die 2, the angle of rotation of lower punch 3 around the central axis, the rotational angular velocity of lower punch 3 and the amount of forming pressure to simulate the forming process, so as to determine the There is no interference between them.

In this embodiment, taking the precision forming of a floating concave die for a helical cylindrical gear with 18 teeth, a normal modulus of 2, a pressure angle of 20 degrees, a helix angle of 16 degrees, and a tooth width of 15 mm as an example, combined with the drawings and implementation Cases are used to further describe the present invention, and of course the following examples should not be regarded as limiting the present invention.

Referring to Figure 2 to Figure 12, the specific steps for determining the floating mold of the helical cylindrical gear are as follows:

(1) Establish the three-dimensional geometric model of the helical cylindrical gear part, the specific process is as follows:

1. According to the basic parameters of the helical cylindrical gear, that is, the number of teeth is 18, the normal modulus is 2, the pressure angle is 20 degrees, the helix angle is 16 degrees, and the tooth width is 15 mm, enter the corresponding expression in the UG software;

2. Use UG software to draw two involute curves, and then draw a complete end face involute tooth groove profile curve according to the basic parameters of the gear;

3. In order to effectively avoid the distortion and deformation of the alveolar, multiple helical lines are used as guide lines during the sweeping process, and multiple planes are evenly inserted between the upper and lower end faces and the tooth profile curve is projected on it as the sweeping curve. Establish precise cogging, as shown in Figure 2 to Figure 3;

4. Perform a Boolean difference operation on the generated single tooth groove and tooth root cylinder, and then use the array to generate a helical cylindrical gear part, as shown in Figure 4.

(2) Design the forging diagram of the helical cylindrical gear: According to the part diagram of the helical cylindrical gear (as shown in Figure 5), the tooth width in the forging diagram is 15 mm, and the forging diagram is designed. The forging diagram is based on the part diagram plus mechanical Machining allowance and forging tolerance. The height of the forging in the forging diagram is 17mm. The volume of the helical cylindrical gear part is calculated by UG software. According to the principle of constant volume, the blank size of the helical cylindrical gear is determined according to the height of the forging and the size of the part. Thus, the gear forming depression amount L=hh ₁ =26-17=9mm is determined.

(3) The structure of the helical cylindrical gear mold is designed based on the principle of floating die (as shown in Figure 6 to Figure 7), and the specific steps are as follows:

One, the speed of upper punch 1 and die 2 should be selected according to the parameter of press, when adopting hydraulic press to form spiral cylindrical gear in the present invention, its forming force F can calculate according to empirical formula F=zmAp,

Among them, p=σ _s (1+0.17d/h), in the formula, F is the forming force (N); z is the deformation condition coefficient, and z is 1.8 when die forging complex shape forgings; m is the deformation volume influence coefficient, when When the volume of the blank is less than 25cm ³ , m is taken as 1; A is the projected area of the forging in the direction perpendicular to the force (mm ² ); p is the unit pressure (MPa); σ _s is the tensile yield limit of the blank metal (MPa), When the blank material is 20CrMnTiH, its tensile yield limit is 835MPa.

According to the above formula, it can be calculated that in the temperature precision forming, the forming force required for the given size of the spiral cylindrical gear in the present invention is 1262KN, so the Y32-300 hydraulic press is selected, its nominal pressure is 3000KN, and its working stroke speed is 4.3 ~ 300mm /s, that is, the axial speed of the upper punch 1 and the die 2 should be between 4.3 and 300mm/s. In addition, the forming speed of the upper punch 1 and the die 2 needs to be determined in combination with the actual production, and meet the requirements Select the working stroke speed of the press.

In the present invention, the velocity of _upper punch 1 is set constant v = 10mm/s, and the speed _of die 2 is respectively taken as v = v _{concave ,} v = 0.5v _{concave ,} v = 2v _concave , then this The speed difference between upper punch 1 and die 2 is 0mm/s, 10mm/s, -5mm/s respectively.

In order to make the concave die 2 float up and down more smoothly and the gear forming effect is better, both the upper punch 1 and the lower punch 3 are designed as spiral cylindrical tooth-shaped punches, and the gear parameters are the same as those of the spiral cylindrical gear, as shown in Figure 8 shown. Similarly, the gear parameters of blank 4 are the same as those of the helical cylindrical gear. When the forming pressing force L is 9 mm, the heights of the cavity of the die 2, the upper punch 1, and the lower punch 3 can be calculated according to the formula in the above step S20, and a certain processing allowance and assembly allowance are considered, and it is obtained The cavity heights of die 2 are 28mm, 37mm, and 28mm (corresponding to three axial speed differences), the heights of upper punch 1 are 15mm, 10mm, and 20mm, and the heights of lower punch 3 are 10mm, 20mm, 10mm.

2. Because the cavity of the cavity of the cavity 2 belongs to the internal helical cylindrical gear, on the basis of the above-mentioned existing gear model, the Boolean operation function in the UG software can be used to calculate the cavity of the cavity of the cavity 2, and according to the cavity of the cavity of the cavity 2 The height and the size of the helical cylindrical gear part to be formed establish the three-dimensional geometric model of the die 2, as shown in Figure 9;

According to the height of the upper punch 1 and the basic parameters of the helical cylindrical gear, the three-dimensional geometric model of the upper punch 1 is established in UG;

According to the height of the lower punch 3 and the basic parameters of the helical cylindrical gear, the three-dimensional geometric model of the lower punch 3 is established in UG;

3. Assemble the three-dimensional geometric model of the established die 2, upper punch 1, lower punch 3 and blank 4: when the height of the blank 4 is h=26mm and the amount of pressing L=9mm, determine the die 2 The relative position of the lower end surface and the upper end surface of the lower punch 3 (the selection of parameters needs to ensure that the mold is always in a closed state during the processing), from the calculation of the formula in the above step S20, it can be known that the rotation angle α = 7.896428582rad, according to the rotation of the helical cylindrical gear Rotate the lower punch 3 along the central axis by an angle α so that the die 2 and the lower punch 3 are in the meshing state, and use UG software to detect whether there is interference between the die 2 and the lower punch 3, and assemble other molds if there is no interference Structure (upper punch 1 and blank 4). If the rotation angle α is inaccurate, the concave die 2 will interfere with the lower punch 3, causing severe wear of the die and affecting the gear forming effect, as shown in Figures 10 to 11.

After the die 2 and the lower punch 3 are assembled, the blank 4 is assembled, and the upper punch 1 is finally assembled. When assembling the blank 4, make its bottom end face fit with the upper end face of the lower punch 3, and at the same time keep the blank 4 and the die 2 engaged by the rotation angle α. Rotate the upper punch 1 along the central axis by an angle α according to the direction of rotation of the helical cylindrical gear, so that the upper punch 1 and the die 2 are kept in mesh.

(4) Import the STL file generated by the UG software in step (3) (that is, the assembled die 2, upper punch 1, lower punch 3 and blank 4) into the DEFORM-3D finite element software to create a helical cylindrical gear Three-dimensional finite element model and simulate its forming process. During the gear forming process, the upper punch 1 and the die 2 perform axial feed movement, and the axial speeds of the upper punch 1 and the die 2 are respectively in step (3). The three sets of parameters are set to control the lower punch 3 to be axially stationary and rotate at a rotational angular velocity ω (as shown in Figure 12), and stop the rotation when the rotation angle of the lower punch 3 along the central axis reaches α, according to According to the rotation angular velocity formula, three kinds of axial velocity settings of upper punch 1 and die 2 are respectively ω ₁ =0.1531318643rad/s, ω ₂ =0.3062637287rad/s, ω ₃ =0.07656593217rad/s. According to the analysis of numerical simulation results, during the gear forming process, there is no interference phenomenon between the molds and the gear forming effect is good. In addition, the analysis of numerical simulation results shows that whether the mold is always closed during processing, and when the mold is not closed during processing, it is necessary to redesign or adjust the relative position of the lower end surface of the die 2 and the upper end surface of the lower punch 3 Machining allowance and assembly allowance l, to ensure that the mold is always closed during processing.

The method for determining the structure of the floating die of the helical cylindrical gear based on the speed difference provided by the present invention uses the principle of the floating die and the meshing principle of the helical cylindrical gear to quickly design the three-dimensional die structure of the floating die for the precision forming of the helical cylindrical gear based on the UG three-dimensional software. The element software analysis provides a geometric data model, which facilitates the rapid establishment of the three-dimensional finite element model of the upper punch 1 and the die 2 at different axial speeds, which saves the time of repeated modeling and avoids the interference of each mold. Improves the efficiency of predicting the forming quality of the floating die for precise forming of the spiral cylindrical gear when the speed difference between the upper punch 1 and the die 2 is used, and facilitates the design of the various mold sizes and processing parameters of the floating die for the spiral cylindrical gear. Provide a basis for the determination of precision forming process.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technical fields, are all the same. included in the scope of patent protection of the present invention.

Claims (5)

1. A method for determining the floating die structure of the helical cylindrical gear based on the speed difference, is characterized in that, comprising the following steps: According to the size of the helical cylindrical gear to be formed, its three-dimensional geometric model is established in UG software; Determine the forging size and blank size according to the size of the helical cylindrical gear part to be formed, and calculate the forming pressure according to the forging size and blank size. After setting the axial speed of the upper punch and die, according to the upper punch and die The axial speed of the mold and the amount of forming pressure determine the cavity height of the die, the height of the upper punch, the height of the lower punch, the angle of rotation of the lower punch around the central axis, and the rotational angular velocity of the lower punch; According to the size of the helical cylindrical gear part to be formed and the determined cavity height of the die, use its Boolean operation function in UG software to establish a three-dimensional geometric model of the die, and according to the size of the helical cylindrical gear part to be formed, determine the cavity height The height of the upper punch, the height of the lower punch and the size of the blank are respectively established in the UG software to establish the three-dimensional geometric models of the upper punch, the lower punch and the blank; Assemble the three-dimensional geometric model of the concave die, upper punch, lower punch and blank established in the UG software according to the amount of forming pressure and the angle rotated by the lower punch around the central axis; Import the three-dimensional geometric models of the assembled die, upper punch, lower punch and blank in the UG software into the DEFORM-3D finite element software, establish a three-dimensional finite element model for precision forming of the floating die of the spiral cylindrical gear, and input the above The axial speed of the punch and die, the rotation angle of the lower punch around the central axis, the rotational angular velocity of the lower punch, and the amount of forming pressure simulate the forming process to ensure that there is no interference between the molds. 2. The method for determining the floating die structure of the spiral cylindrical gear based on the speed difference as claimed in claim 1, wherein the forging size and the blank size are determined according to the size of the spiral cylindrical gear part to be formed, and according to the forging size and the blank size The process of calculating the forming downforce is as follows: Determine its forging size according to the size of the helical cylindrical gear part to be formed, calculate its part volume in UG software according to the size of the helical cylindrical gear part to be formed, and determine the blank size according to the forging size and part volume, according to the blank size and The size of the forging is calculated by the following formula: L=hh ₁ , wherein, L is the forming depression, h ₁ is the height of the forging, and h is the height of the blank. 3. The method for determining the floating die structure of the helical cylindrical gear based on the speed difference as claimed in claim 2, wherein, after setting the axial speed of the upper punch and the die, according to the axial speed of the upper punch and the die, The specific process of determining the cavity height of the die, the height of the upper punch, the height of the lower punch, the angle of rotation of the lower punch around the central axis, and the rotational angular velocity of the lower punch is as follows: When the axial speed of the upper punch is v _, the axial speed of the die is v _concave = bv _, when b is a constant, the cavity height H of the die is _concave , the height of the upper punch H is the height of _{the upper} and lower punches The angle α of the rotation of the _lower and lower punches around the central axis and the rotational angular velocity ω of the lower punch are calculated by the following formula: ΔH=Δv×t, Δv=(v _concave -v _up ), t=L/min(v _up , v _concave ); When Δv is zero, H _concave =h+l, H _up =h ₁ +l, H _down =L+l; When Δv is positive, H _concave =h+ΔH+l, H _up =L+l, H _down =L+ΔH+l; When Δv is negative, H _concave =h+l, H _up =L+|ΔH|+l, H _down =L+l; α=180Ltan(β _b )/(πr _b ); ω=α/t; Among them, ΔH is the height difference between the lower end surface of the upper punch and the upper end surface of the die, Δv is the axial speed difference between the die and the upper punch, t is the time for forming the spiral cylindrical gear, l is the machining allowance and Assembly margin, β _b = arctan(tan(β)cos(α _t )), t=L/min(v _up , v _concave ), β _b is the base circle helix angle, β is the gear helix angle, α _t is The pressure angle of the end face of the gear indexing circle, r _b is the radius of the base circle. 4. the method for determining the floating die structure of the helical cylindrical gear based on the speed difference as claimed in claim 1, is characterized in that, when setting the axial speed of the upper punch and die, according to the corresponding press of the helical cylindrical gear floating die Parameter selection, after the press is selected, the axial speeds of the upper punch and the die are all within the working stroke speed range of the selected press. 5. The method for determining the floating die structure of the helical cylindrical gear based on the speed difference according to any one of claims 1 to 4, characterized in that, according to the size of the helical cylindrical gear part to be formed, the height of the upper punch, and the height of the lower punch The specific process of establishing the three-dimensional geometric model of the upper punch, the lower punch and the blank in the UG software for height and blank size is as follows: According to the size of the helical cylindrical gear part to be formed and the height of the upper punch, the three-dimensional geometric model of the upper punch is established in the UG software. The upper punch is a helical cylindrical tooth-shaped punch. Punch height Establish the three-dimensional geometric model of the lower punch in the UG software. The lower punch is a helical cylindrical tooth-shaped punch. According to the size of the helical cylindrical gear part and the blank size to be formed, the three-dimensional geometric model of the blank is established in the UG software. .