Die for non-cutting fine forming of inner gear ring

Abstract

A die for non-cutting fine net forming of an inner gear ring belongs to the technical field of dies, solves the technical problem that a metal flow line is cut off in the plastic deformation process of the gear ring, and adopts the scheme that a fine net forming tooth roller is continuously or intermittently and spirally fed downwards in the axis direction, so that a straight tooth shape is formed on the inner circular surface of an annular blank in an inserting and grinding composite manner; an initial guiding section, a biting section, a material distributing section, a tooth shape pre-forming section, an involute forming section and a tooth shape finishing section are sequentially arranged on the fine net forming tooth roller, and the multiple sections of forming teeth are equal in tooth number and are sequentially connected. When the gear ring is subjected to insertion and grinding composite forming, a complete metal streamline is formed in the plastic deformation process of the gear ring, the strength, corrosion resistance and wear resistance of the gear surface of the gear ring are improved, and the service life of the gear ring is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of molds, and particularly relates to a mold for forming an internal gear ring without cutting. Background Art

[0002] Gears and gear rings are common mechanical transmission parts, which are widely used in industrial production in various fields. The current manufacturing process of gear rings is: forging (or ring rolling) to form ring blanks, initial turning of blanks, and mechanical processing of gear shaping (or gear hobbing) to form tooth profiles. Not only is the process route lengthy, the manufacturing cycle is long, and large-scale processing equipment is seriously occupied; at the same time, because the tooth profile is formed by mechanical processing, the plastically deformed metal streamline is cut off, resulting in fiber leakage, making the tooth surface more susceptible to corrosion, wear, surface shedding, etc., and easily causing the root of the tooth to break, etc., which ultimately leads to a serious reduction in the service life and service cycle of the gear ring. How to form a full-fiber streamline tooth profile and increase the service life of the gear ring has become an urgent problem to be solved. Summary of the invention

[0003] The main purpose of the present invention is to overcome the deficiencies in the prior art and solve the technical problem that metal streamlines are cut off during the plastic deformation of the gear ring. The present invention provides a mold for precision forming of an internal gear ring without cutting.

[0004] Compared with the prior art, the present invention is achieved through the following technical solutions:

[0005] A die for non-cutting precision forming of an internal gear ring, comprising a precision forming gear roller, a driving roller and a pressing roller, wherein the driving roller presses the outer circumferential surface of an annular blank, and two pressing rollers respectively press the upper and lower end surfaces of the annular blank, wherein: the precision forming gear roller is arranged vertically downward, and the outer wall of the precision forming gear roller presses the inner circumferential surface of the annular blank, the axial direction of the precision forming gear roller is perpendicular to the horizontal plane where the annular blank is located, and the precision forming gear roller is continuously or intermittently fed downward in a spiral along the axial direction, thereby inserting and rolling the composite forming straight tooth profile on the inner circumferential surface of the annular blank;

[0006] The fine forming gear roller is configured as a plurality of long shaft parts with forming teeth, the plurality of forming teeth have an equal number of teeth and are connected in sequence, and the pitch circle of each section on the fine forming gear roller is Φ 轴 The pitch circle of the inner gear ring after the ring blank is formed is Φ 坯 Tangent, and at any moment the pitch circle Φ 轴 With the pitch circle Φ 坯 The linear velocities at the point of tangency are equal: v 轴 =v 坯 ; At any time, the dividing circle Φ 轴 With the pitch circle Φ 坯 The ratio of the angular velocities at the point of tangency is equal to the inverse ratio of the pitch circle diameter:

[0007] From the head to the tail of the precision forming gear roller, the initial guide section, the biting section, the material dividing section, the tooth profile preforming section, the involute forming section and the tooth profile finishing section are coaxially arranged in sequence according to the forming process;

[0008] The initial guide segment is set to be cylindrical, and the length of the initial guide segment is not less than 1 / 2 of the height of the blank; in the initial state of the insertion and rolling composite forming, the outer cylindrical surface of the initial guide segment is tangent to the inner cylindrical surface of the annular blank;

[0009] The biting section, the outer wall of the biting section is set as a conical surface, the small end face of the biting section is connected to the initial guide section, the outer wall of the biting section is provided with biting cone teeth, the taper of the biting cone teeth (i.e., the rapid biting angle) is α, 8°≤α≤15°; the driving roller in the present invention is a power input device for the "rolling ring forming" of the annular blank, that is, the driving roller drives the annular blank to rotate along the circumferential direction, when the biting section of the fine forming tooth roller is inserted into the annular blank, the annular blank drives the fine forming tooth roller to rotate around the axis direction, and at the same time, the fine forming tooth roller is downwardly "gear-inserted" to finally realize the "insertion" and "rolling" composite forming of the fine forming tooth roller;

[0010] Because in the internal gear ring insertion and rolling composite forming process, the rotation of the precision forming gear roller needs to match the rotation of the blank, so that the pitch circle always remains tangent and there can be no slipping relative movement. The rotation relationship is related to the number of teeth, module, and pitch circle size of the gear ring. The taper of the biting bevel teeth enables the biting section of the precision forming gear roller to quickly insert into the inner circle of the annular blank to achieve biting, thereby ensuring that there is no relative movement between the rotation of the forming mold and the rotation of the blank.

[0011] The material dividing section, the outer wall of the material dividing section is set as a conical surface, the small end surface of the material dividing section is connected to the large end surface of the biting section, and the material dividing cone teeth are arranged on the outer wall of the material dividing section, each material dividing cone tooth is respectively connected to the corresponding biting cone tooth, the taper of the material dividing cone tooth is β, 3°≤β≤10°, and β<α, and the ratio of the length of the generatrix of the biting section to the length of the generatrix of the material dividing section is not greater than 1 / 3;

[0012] After the biting section of the precision forming tooth roller quickly bites into the inner surface of the ring blank, it enters the stable material distribution stage. The working principle of the material distribution section is based on the blank making and pre-forging process of die forging to achieve further distribution of the blank metal. The taper of the material distribution cone is β (i.e., the insertion angle), which is a critical parameter and will directly affect the rolling force, die insertion force, and equipment operation stability.

[0013] The tooth profile preforming section, involute forming section and tooth profile finishing section are all arranged as spur gear shafts, the tooth profile preforming section is connected to the large end face of the dividing section, the number of teeth, module, addendum circle, root circle and base circle of the tooth profile preforming section, involute forming section and tooth profile finishing section are all the same, the tooth profile profile of the tooth profile preforming section is a trapezoidal profile, and the tooth profile profile of the involute forming section and the tooth profile finishing section is an involute profile; wherein:

[0014] The tooth profile preforming section is used to preform the entire forming tooth into a trapezoidal cross section along the height direction of the annular blank, that is, the volume (or cross-sectional area) of the forming tooth of the tooth profile preforming section of the precision forming gear roller pressed into the gear ring is equal to the volume (or cross-sectional area) of the blank that is reversely squeezed into the tooth groove of the adjacent forming tooth;

[0015] The involute forming section is used to form the tooth profile of the internal gear ring from a trapezoidal cross-sectional profile to an involute cross-sectional profile;

[0016] The tooth profile finishing section finishes the tooth profile section into an involute internal gear ring.

[0017] Furthermore, a positioning section is arranged at the front end of the initial guide section, the positioning section is arranged in a truncated cone shape, and the diameter of the large end of the positioning section is equal to the diameter of the initial guide section.

[0018] The beneficial effects of the present invention are as follows: from the head to the tail of the precision-formed gear roller, the following are coaxially arranged in sequence according to the forming process: the initial guide section, the biting section, the material dividing section, the tooth profile pre-forming section, the involute forming section and the tooth profile finishing section. A complete metal streamline is formed during the plastic deformation of the spur teeth of the gear ring, thereby improving the strength, corrosion resistance and wear resistance of the tooth surface of the gear ring and extending the service life of the gear ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the main structure of the precision formed gear roller;

[0021] Figure 3 for Figure 2 A schematic diagram of a local enlarged structure;

[0022] Figure 4 It is a tooth profile comparison diagram of the biting section, the material dividing section, the tooth profile pre-forming section, the involute forming section and the tooth profile finishing section; among which, Figure AA is Figure 2 The view in the AA direction, Figure BB is Figure 2 The view from the BB direction, Figure CC is Figure 2 View from CC direction, Figure DD is Figure 2 The view from the DD direction is shown in Figure EE. Figure 2View in the EE direction.

[0023] In the figure, 1 is the precision forming gear roller, 1-1 is the initial guide section, 1-2 is the biting section, 1-3 is the material dividing section, 1-4 is the tooth profile pre-forming section, 1-5 is the involute forming section, 1-6 is the tooth profile finishing section, 1-7 is the positioning section, 2 is the driving roller, 3 is the pressure roller, and 4 is the ring blank. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] like Figures 1 to 4 The mold for non-cutting precision forming of an internal gear ring shown in the figure comprises a precision forming gear roller 1, a driving roller 2 and a pressing roller 3, wherein the driving roller 2 presses the outer circumferential surface of an annular blank 4, and the two pressing rollers 3 respectively press the upper and lower end surfaces of the annular blank 4, wherein: the precision forming gear roller 1 is vertically arranged downward, and the outer wall of the precision forming gear roller 1 presses the inner circumferential surface of the annular blank 4, the axial direction of the precision forming gear roller 1 is perpendicular to the horizontal plane where the annular blank 4 is located, and the precision forming gear roller 1 is continuously or intermittently fed downward in a spiral along the axial direction, thereby inserting and rolling the composite forming spur tooth shape on the inner circumferential surface of the annular blank 4;

[0026] The fine forming gear roller 1 is configured as a plurality of long shaft parts with forming teeth, the plurality of forming teeth have the same number of teeth and are connected in sequence, and the pitch circle Φ of each section of the fine forming gear roller 1 is 轴 The pitch circle of the inner gear ring after the ring blank 4 is formed is Φ 坯 Tangent, and at any moment the pitch circle Φ 轴 With the pitch circle Φ 坯 The linear velocities at the point of tangency are equal: v 轴 =v 坯 ; At any time, the dividing circle Φ 轴 With the pitch circle Φ 坯 The ratio of the angular velocities at the point of tangency is equal to the inverse ratio of the pitch circle diameter:

[0027] From the head to the tail of the fine forming gear roller 1, an initial guide section 1-1, a biting section 1-2, a material dividing section 1-3, a tooth profile preforming section 1-4, an involute forming section 1-5 and a tooth profile finishing section 1-6 are coaxially arranged in sequence according to the forming process;

[0028] The initial guide segment 1-1 is set to be cylindrical, and the length of the initial guide segment 1-1 is not less than 1 / 2 of the height of the blank; in the initial state of the insertion and rolling composite forming, the outer cylindrical surface of the initial guide segment 1-1 is tangent to the inner cylindrical surface of the annular blank 4;

[0029] The biting section 1-2, the outer wall of the biting section 1-2 is set as a cone surface, the small end surface of the biting section 1-2 is connected to the initial guide section 1-1, and the outer wall of the biting section 1-2 is provided with biting cone teeth, and the taper of the biting cone teeth is α, 8°≤α≤15°;

[0030] The dividing section 1-3, the outer wall of the dividing section 1-3 is set as a conical surface, the small end surface of the dividing section 1-3 is connected to the large end surface of the biting section 1-2, and the outer wall of the dividing section 1-3 is provided with dividing cone teeth, each dividing cone tooth is respectively connected to the corresponding biting cone tooth, the taper of the dividing cone teeth is β, 3°≤β≤10°, and β<α, the ratio of the length of the generatrix of the biting section 1-2 to the length of the generatrix of the dividing section 1-3 is not greater than 1 / 3;

[0031] The tooth preforming section 1-4, the involute forming section 1-5 and the tooth finishing section 1-6 are all arranged as spur gear shafts, the tooth preforming section 1-4 is connected to the large end face of the dividing section 1-3, the number of teeth, module, addendum circle, root circle and base circle of the tooth preforming section 1-4, the involute forming section 1-5 and the tooth finishing section 1-6 are all the same, the tooth profile of the tooth preforming section 1-4 is a trapezoidal profile, and the tooth profile of the involute forming section 1-5 and the tooth finishing section 1-6 is an involute profile; wherein:

[0032] The tooth profile preforming section 1-4 is used to complete the preforming of the trapezoidal cross section of the entire forming tooth along the height direction of the annular blank 4, that is, the volume of the forming teeth pressed into the gear ring by the tooth profile preforming section 1-4 of the precision forming gear roller 1 is equal to the volume of the blank being reversely squeezed into the tooth groove of the adjacent forming tooth;

[0033] The involute forming section 1-5 is used to form the tooth profile of the inner gear ring from a trapezoidal cross-sectional profile to an involute cross-sectional profile;

[0034] The tooth profile finishing section 1-6 finishes the tooth profile cross section into an involute internal gear ring.

[0035] Furthermore, in order to enable the precision formed gear roller 1 to be better introduced into the inner circle of the ring blank 4, a positioning section 1-7 is arranged at the front end of the initial guide section 1-1. The positioning section 1-7 is arranged in a truncated cone shape, and the diameter of the large end of the positioning section 1-7 is equal to the diameter of the initial guide section 1-1.

[0036] The insert-rolling composite forming process for non-cutting precision forming of the internal gear ring using the above-mentioned mold includes the following steps:

[0037] S1. Initial guide: The ring blank 4 is mounted on the ring rolling device, the driving roller 2 is pressed against the outer circumference of the ring blank 4, the pressing roller 3 is pressed against the upper and lower end faces of the ring blank 4, and the initial guide section 1-1 of the precision forming gear roller 1 is pressed against the inner circumference of the ring blank 4;

[0038] S2, biting: the ring rolling equipment drives the fine forming gear roller 1 to move downward along the axial direction to the biting section 1-2, and the fine forming gear roller 1 is continuously or intermittently fed downward in the axial direction to form a tooth groove corresponding to the biting cone tooth shape on the inner circumferential surface of the ring blank 4;

[0039] S3, material division: the ring rolling equipment drives the fine forming gear roller 1 to continue to move along the axis to the material division section 1-3, and the fine forming gear roller 1 is continuously or intermittently fed downward in the axial direction to form a tooth groove corresponding to the tooth shape of the material division cone on the inner surface of the ring blank 4;

[0040] S4, tooth profile preforming: the ring rolling equipment drives the fine forming gear roller 1 to move downward along the axial direction to the tooth profile preforming section 1-4, and the fine forming gear roller 1 is continuously or intermittently fed downward in the axial direction to form tooth grooves corresponding to the tooth profile of the tooth profile preforming section 1-4 on the inner circumferential surface of the ring blank 4;

[0041] S5, involute forming: the ring rolling equipment drives the precision forming gear roller 1 to move along the axis to the involute forming section 1-5, and processes the tooth groove formed on the inner surface of the ring blank 4 in step S4 into an involute tooth groove;

[0042] S6, tooth shape finishing: the ring rolling equipment drives the fine forming gear roller 1 to move along the axis to the tooth shape finishing section 1-6, and the tooth shape finishing section 1-6 finishes the involute tooth groove formed on the inner circumferential surface of the ring blank 4 in step S5, completing the insertion and rolling composite non-cutting fine forming internal gear ring processing.

[0043] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A die for non-cutting precision forming of an internal gear ring, comprising a precision forming gear roller (1), a driving roller (2) and a pressing roller (3), wherein the driving roller (2) presses the outer circumferential surface of an annular blank (4), and the two pressing rollers (3) respectively press the upper and lower end surfaces of the annular blank (4), characterized in that: The precision forming gear roller (1) is arranged vertically downward, and the outer wall of the precision forming gear roller (1) presses the inner circumferential surface of the annular blank (4), the axial direction of the precision forming gear roller (1) is perpendicular to the horizontal plane where the annular blank (4) is located, and the precision forming gear roller (1) is continuously or intermittently fed downward in a spiral along the axial direction, thereby inserting and rolling the composite spur gear shape on the inner circumferential surface of the annular blank (4); The clean forming gear roller (1) is configured as a plurality of long shaft parts with forming teeth, the plurality of forming teeth have an equal number of teeth and are connected in sequence, and the pitch circle Φ of each section of the clean forming gear roller (1) is 轴 The pitch circle Φ of the inner gear ring after the ring blank (4) is formed 坯 Tangent, and at any moment the pitch circle Φ 轴 With the pitch circle Φ 坯 The linear speed at the point of tangency is equal: v 轴 =v 坯 ; At any time, the dividing circle Φ 轴 With the pitch circle Φ 坯 The ratio of the angular velocities at the point of tangency is equal to the inverse ratio of the pitch circle diameter: An initial guide section (1-1), a biting section (1-2), a material dividing section (1-3), a tooth profile preforming section (1-4), an involute forming section (1-5) and a tooth profile finishing section (1-6) are coaxially arranged in sequence from the head to the tail of the fine forming tooth roller (1) according to the forming process; An initial guide segment (1-1) is set in a cylindrical shape, and the length of the initial guide segment (1-1) is not less than 1 / 2 of the height of the blank; in the initial state of the insertion and rolling composite forming, the outer cylindrical surface of the initial guide segment (1-1) is tangent to the inner cylindrical surface of the annular blank (4); A biting section (1-2), the outer wall of the biting section (1-2) is arranged as a conical surface, the small end surface of the biting section (1-2) is connected to the initial guide section (1-1), biting conical teeth are arranged on the outer wall of the biting section (1-2), the taper of the biting conical teeth is α, 8°≤α≤15°; A material dividing section (1-3), the outer wall of the material dividing section (1-3) is arranged as a conical surface, the small end surface of the material dividing section (1-3) is connected to the large end surface of the biting section (1-2), a material dividing cone tooth is arranged on the outer wall of the material dividing section (1-3), each material dividing cone tooth is respectively connected to the corresponding biting cone tooth, the taper of the material dividing cone tooth is β, 3°≤β≤10°, and β<α, and the ratio of the length of the generatrix of the biting section (1-2) to the length of the generatrix of the material dividing section (1-3) is not greater than 1 / 3; The tooth profile preforming section (1-4), the involute forming section (1-5) and the tooth profile finishing section (1-6) are all arranged as spur gear shafts, the tooth profile preforming section (1-4) is connected to the large end face of the dividing section (1-3), the tooth number, module, tooth top circle, tooth root circle and base circle of the tooth profile preforming section (1-4), the involute forming section (1-5) and the tooth profile finishing section (1-6) are all the same, the tooth profile profile of the tooth profile preforming section (1-4) is a trapezoidal profile, and the tooth profile profiles of the involute forming section (1-5) and the tooth profile finishing section (1-6) are involute profiles; wherein: The tooth profile preforming section (1-4) is used to complete the preforming of the trapezoidal cross section of the entire forming tooth along the height direction of the annular blank (4), that is, the volume of the forming tooth pressed into the gear ring by the tooth profile preforming section (1-4) of the precision forming tooth roller (1) is equal to the volume of the blank extruded back into the tooth groove of the adjacent forming tooth; The involute forming section (1-5) is used to form the tooth profile of the internal gear ring from a trapezoidal cross-sectional profile to an involute cross-sectional profile; The tooth profile finishing section (1-6) finishes the tooth profile section to form an involute internal gear ring.

2. The die for non-cutting precision forming of an internal gear ring according to claim 1, characterized in that: A positioning section (1-7) is arranged at the front end of the initial guide section (1-1); the positioning section (1-7) is arranged in a truncated cone shape; and the diameter of the large end of the positioning section (1-7) is equal to the diameter of the initial guide section (1-1).

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