Double-radial-plate herringbone gear structure and mounting method thereof

Abstract

The invention relates to the technical field of gear transmission, and discloses a double-radial-plate herringbone gear structure and a mounting method.The gear structure comprises a gear shaft, an upper radial plate, a lower radial plate and a gear ring, a flange is arranged on the periphery of the gear shaft, and the ends, close to the gear shaft, of the lower radial plate and the upper radial plate are symmetrically arranged along the two sides of the flange; and one ends, far away from the gear shaft, of the lower radial plate and the upper radial plate are connected with two groups of mounting edges of the gear ring through step outer circles. From the aspect of structure, the gear ring part and the wheel disk part of the herringbone gear are separately designed and machined and are connected through the connecting piece, so that the wheel disk part and the gear ring part of the gear form a stable triangular supporting structure, the structural stability is better, and the operation stability of a gear pair is improved; meanwhile, the gear shaft, the radial plate and the gear ring are made of different materials, and the radial plate is made of titanium alloy or composite materials, so that the overall weight of the gear is lighter, the power density of a helicopter speed reducer is improved, and the advancement of products is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gear transmission, and particularly relates to a double-web plate herringbone gear structure and a mounting method thereof. BACKGROUND

[0002] The herringbone gear is often used in a large-tonnage helicopter main reducer low-speed stage large transmission ratio split-torque transmission configuration due to its characteristics of stable meshing and no axial force, and the driven herringbone gear diameter usually reaches more than 800 mm. At present, the large-specification herringbone gears in existing helicopter models are mostly designed in an integrated structure of a gear and a web plate.

[0003] Due to the large diameter and heavy weight of the gear ring part (including the gear teeth and the rim), the web plate structure needs to be designed to not only meet the gear transmission torque but also focus on supporting the self-weight of the gear ring part, so that the web plate design thickness is usually thick, the entire gear weight accounts for a high proportion of the total weight of the reducer, which is not conducive to the lightweight design index of the reducer. In addition, the integrated design of the large disc gear greatly increases the difficulty of gear machining and heat treatment deformation control, not only the manufacturing cost is high, but also the gear tooth surface layer uniformity and gear shaft assembly dynamic balance performance are affected, which finally affects the service life of the gear and the dynamics of the reducer system.

[0004] The present application provides a new idea from the structure aspect, and designs a large-size double-web plate herringbone gear structure, which is designed and processed separately from the herringbone gear ring part and the web plate part, and is connected through a connecting piece, so that the gear web plate and the gear ring part form a stable triangular support structure, which is conducive to solving the above problems. SUMMARY

[0005] In view of the technical problems mentioned above, the present application provides a double-web plate herringbone gear structure and a mounting method thereof, which can effectively improve the above problems.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: Firstly, a double-web plate herringbone gear structure is provided, comprising: A gear shaft, a flange is integrally formed on the outer periphery of the gear shaft; A lower web plate and an upper web plate, a stepped outer circle is arranged at the end of the lower web plate and the upper web plate away from the gear shaft, and through holes and pin holes are arranged in a ring shape at the top of the stepped outer circle; A gear ring, two groups of mounting edges are integrally formed on the inner side wall of the gear ring, and screw holes and pin holes are arranged in a ring shape at the top of the two groups of mounting edges; The end of the lower web plate and the upper web plate close to the gear shaft is symmetrically arranged on both sides of the flange and connected with the flange through a bolt assembly, and the two groups of mounting edges of the gear ring are connected with the stepped outer circles on the lower web plate and the upper web plate through screws, respectively.

[0007] Preferably, it also includes shear pins, wherein the plurality of shear pins are spaced apart on the distribution circle where the screw is located, and are installed through pin holes on the gear ring and the lower and upper spokes.

[0008] Preferably, the outer periphery of the shear pin has a raised arc structure, which is engaged in the chamfer of the pin hole on the contact surface between the lower spoke, the upper spoke and the gear ring.

[0009] Preferably, the bolts in the bolt assembly have a clearance fit with the connecting holes of the flange, lower spoke, and upper spoke.

[0010] Preferably, the screw passes through the through hole and is threadedly connected to the threaded hole, and a set of double-locking washers are provided at the bottom of the screw heads of two adjacent sets of screws.

[0011] Preferably, the gear ring is made of gear steel, and the lower and upper spokes are made of titanium alloy or composite material.

[0012] Preferably, the outer peripheral sidewall of the gear ring is provided with a relief groove, the width of which is set as a, and the tooth width of the gear ring is set as b. The relief groove width a and the tooth width b satisfy: a≤0.75b; The span between the two sets of mounting sides on the gear ring is set as c; The span c satisfies: a+b≤c≤a+1.3b.

[0013] Preferably, the lower spoke and the upper spoke are installed at the same height, wherein the installation height of the lower spoke is set as d and the installation height of the upper spoke is set as e.

[0014] Preferably, the installation angle between the lower and upper spokes and the gear ring is set to θ, the axial meshing force borne by one side of the herringbone gear teeth is set to Fa, and the radial meshing force borne by one side of the herringbone gear teeth is set to Fr, wherein the installation angle θ, the axial meshing force Fa, and the radial meshing force Fr satisfy: θ≥arctan(Fr / Fa).

[0015] Preferably, the flange thickness is set as f, and the flange thickness f satisfies: f=cde.

[0016] Secondly, a method for installing a double-spoke herringbone gear is provided, which includes the herringbone gear structure described above, and also includes the following installation steps: The gear shaft, lower spoke, upper spoke, and gear ring are machined separately according to the design dimensions; By using an unlocked bolt assembly, the end of the upper spoke plate away from the outer circle of the step is lapped onto the upper side of the flange of the gear shaft; Insert the shear pin into the pin hole of the upper spoke plate; Align the pin hole on the upper mounting edge of the gear ring with the inserted shear pin, so that it connects with the outer circle of the step on the upper spoke plate. Insert the double locking washers into the through holes on the upper spoke and the gear ring, using the loose screws as a guide. By using an unlocked bolt assembly, the end of the lower spoke away from the outer circle of the step is lapped onto the lower side of the flange of the gear shaft; Insert the shear pin into the pin hole of the lower spoke; Align the pin hole on the mounting edge of the gear ring with the inserted shear pin, so that it connects with the outer circle of the step on the lower spoke plate. Insert the double locking washers into the through holes on the lower spoke and gear ring, using the loose screws as a guide. Tighten the bolt assembly and screws in sequence to form a stable triangular support structure with the lower spoke, upper spoke and gear ring.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The large-size double-spoke herringbone gear of the present invention, through structural design, separately processes the gear shaft, lower spoke, upper spoke, and gear ring, and then assembles them to form a stable triangular support structure. Compared with traditional gear spokes, it has higher support rigidity. When the gear transmits torque and impact loads, the deformation of the gear ring is smaller, the meshing misalignment of the gear pair is smaller, and the structural stability is better. It can effectively improve the uneven load on both sides of the herringbone gear caused by system installation and manufacturing errors, improve the smoothness of gear pair operation, and help improve the smoothness of gear transmission and ensure the reliability of the reducer.

[0018] 2. This invention uses a split-type combination structure of different materials for large-size herringbone gears. Compared with the integrated structure, the split structure uses different materials for the gear shaft, spokes, and gear ring. Among them, the spokes are made of titanium alloy or composite material, which makes the overall weight of the gear lighter, which is conducive to improving the power density of the helicopter reducer and ensuring the product's advanced nature.

[0019] 3. The large-sized split herringbone gear structure designed in this invention is a key moving component in aviation transmission. Its manufacturing cost accounts for a high proportion of the total cost of the reducer product. After separating the gear ring and the spoke, if the tooth surface is damaged during use, the gear ring can be replaced separately, while the spoke and gear shaft can still be reused. This greatly reduces the maintenance cost of the reducer product and improves its economic efficiency.

[0020] 4. This invention designs the gear ring of the herringbone gear into a simple ring structure, which makes it easier to set up machining auxiliary support fixtures and heat treatment clamping fixtures. The deformation of the gear teeth during grinding, carburizing, and quenching is easier to control, effectively avoiding the deformation of the gear spokes and gear shaft during machining and heat treatment. This is beneficial to improving the overall machining accuracy of the gear, improving the uniformity of the carburized layer on the gear surface, and increasing the service life of the gear.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of an integrated single-spoke gear structure in the prior art; Figure 2 This is a schematic diagram of an integrated gear herringbone spoke structure in existing technology; Figure 3 This is a schematic diagram of the herringbone gear split assembly structure provided by the present invention; Figure 4 This is a schematic diagram of the screw mounting structure provided by the present invention; Figure 5 This is a schematic diagram of the shear pin installation structure provided by the present invention; Figure 6 This is a schematic diagram showing the dimensions of each component of the split structure provided by the present invention; Figure 7 This is a schematic diagram of the main working surface structure of the gear provided by the present invention; Figure 8 This is a schematic diagram of the gear force analysis structure provided by the present invention.

[0024] Explanation of reference numerals in the attached figures: 1. Gear shaft; 2. Lower spoke; 3. Gear ring; 4. Upper spoke; 5. Bolt assembly; 6. Screw; 7. Double retaining washer; 8. Shear pin. Detailed Implementation

[0025] 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 clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The same reference numerals in the accompanying drawings denote the same or similar elements, components, or parts, and therefore, repeated descriptions of the same or similar elements, components, or parts may be omitted below. It should also be understood that although terms such as first, second, third, etc., indicating numbers may be used herein to describe various devices, elements, components, or parts, these devices, elements, components, or parts should not be limited by these terms. That is, these terms are only used to distinguish one from another. For example, a first device may also be referred to as a second device, without departing from the essential technical solution of the invention. Furthermore, the terms "and / or" and "and / or" refer to all combinations including any one or more of the listed items.

[0027] The following is in conjunction with the appendix Figure 1 -Appendix Figure 8 Further explanation is needed.

[0028] The main gearbox of a helicopter transmission system is a key component, transmitting engine speed and power to the helicopter rotor. As the low-speed output stage of the gearbox, it features a large transmission ratio and high torque transmission. Herringbone gear pairs are often used in the rotor output stage of helicopter main gearboxes to achieve torque distribution. Typically, the driven herringbone gears in this part are relatively large, with pitch circle diameters exceeding 800mm. Currently, the main helicopter gearboxes in service both domestically and internationally that use large-size herringbone gears for torque distribution are models such as RAH-66 and CH-53K. Their herringbone gear structures all adopt an integrated design of spokes and gear rings, mainly divided into the following two types: like Figure 1 As shown, a schematic diagram of an integrated single-spoke plate structure of the prior art is provided. In this structure, the gear ring (tooth and rim) of the herringbone gear is integrated with the spokes and gear shaft. This is a typical large-size, thin-disc structure. To ensure that the gear has sufficient strength and rigidity, the spokes and rims are usually of gradually varying thickness. That is, the spokes gradually thin as the diameter increases, and the rims gradually thin from the middle of the herringbone teeth to both ends. Herringbone gears of this structural type are typical thin-walled disc structures, which are prone to warping deformation of the spokes during machining and heat treatment. Furthermore, the variable cross-sectional thickness of the gear spokes makes it inconvenient to design and install auxiliary support fixtures, resulting in the spokes being in a free state during grinding or quenching, making gear deformation control even more difficult. In addition, for gears with very large diameters (800mm–1500mm), the gear ring is heavy. When the gear is placed horizontally along its diameter, the gear spokes need to bear the additional weight of the gear ring, causing initial bending deformation of the spokes. This results in uneven loading on the upper and lower teeth of the herringbone gear, which is detrimental to the meshing stability of the herringbone gear pair. When the gear is subjected to large periodic alternating loads, this uneven loading is further amplified, affecting the gear's service life.

[0029] like Figure 2 As shown, a schematic diagram of the integrated herringbone spoke structure of the prior art is provided. In this structure, the gear ring (tooth and rim) of the herringbone gear is integrated with the spokes and gear shaft. To ensure that the gear has sufficient strength and rigidity, the spokes are designed in a herringbone shape, that is, the part near the gear ring is a single spoke, and the part near the gear shaft is a forked double spoke structure. While this type of herringbone gear spoke structure compensates for the weakness of integrated single-spoke structures in terms of rigidity, it significantly increases the overall weight, making it difficult to meet the lightweight design goals of aerospace transmission gears. Furthermore, the integrated design of the gear ring, spokes, and gear shaft necessitates that the spokes and gear shaft undergo carburizing, quenching, and other heat treatments along with the gear teeth. This makes gear support and positioning difficult, and overall heat treatment deformation remains hard to control, resulting in low production yield and high processing costs.

[0030] like Figure 3 As shown, a double-spoke herringbone gear structure of the present invention is provided, including a gear shaft 1, a lower spoke 2, a gear ring 3 and an upper spoke 4, wherein a flange is connected to the outer periphery of the gear shaft 1, and the lower spoke 2 and the upper spoke 4 are symmetrically arranged along both sides of the flange near the end of the gear shaft 1 and are connected to the flange by a bolt assembly 5. In terms of material selection, the gear shaft 1 is the core component for torque transmission. It is made of high-strength steel or stainless steel to give it high torsional strength and improve fatigue life. The tooth surface of the gear ring 3 is used for meshing transmission. It is made of gear steel to strengthen the tooth surface performance and improve its surface hardness and wear resistance. The lower spoke 2 and the upper spoke 4 are made of titanium alloy or composite materials, which makes the overall weight of the gear structure lighter, which is conducive to improving the power density of the helicopter reducer and ensuring the product's advanced nature. Specifically, the precision bolts in bolt assembly 5 are clearance-fitted with the flange, the lower spoke 2 and the upper spoke 4. The clearance is 0.01-0.08mm. Thus, the lower spoke 2 and the upper spoke 4 can be installed on the gear 1 through the joint action of bolt assembly 5 and flange. The reliability of the gear structure is improved by precisely controlling the fit relationship, and its resistance to fretting wear is enhanced. The smooth part of the precision bolt is used to transmit gear torque by bearing shear force. Furthermore, the lower spoke 2 and the upper spoke 4 are provided with a stepped outer circle at the end away from the gear shaft 1. The top of the stepped outer circle is provided with through holes and pin holes arranged in an annular pattern. The inner peripheral wall of the gear ring 3 is integrally formed with two sets of mounting edges. The top of the two sets of mounting edges is provided with threaded holes and pin holes arranged in an annular pattern. The two sets of mounting edges of the gear ring 3 are connected to the stepped outer circle on the lower spoke 2 and the upper spoke 4 respectively by screws 6. Specifically, the pin holes on the lower spoke 2, the upper spoke 4, and the gear ring 3 are all located on different distribution circles of the same radius, and the different distribution circles are all concentric with the axis of the gear shaft. The through holes and pin holes on the lower spoke 2 and the upper spoke 4 are arranged in a ring at intervals on the same distribution circle, and the threaded holes and pin holes on the gear ring 3 are arranged in a ring at intervals on the same distribution circle. Specifically, during installation, the upper spoke 4 and the lower spoke 2 are respectively fitted with the upper and lower mounting edges of the gear ring 3. The upper and lower mounting edges of the gear ring 3 are precisely fitted with the stepped outer circles of the upper spoke 4 and the lower spoke 2, respectively. The threaded holes on the gear ring 3 correspond to the through holes on the spokes, and the pin holes on the gear ring 3 correspond to the pin holes on the spokes, which serves to position the wheel center.

[0031] like Figure 4 As shown, screw 6 passes through the through hole and is threadedly connected to the threaded hole. A set of double stop washers 7 are provided at the bottom of the screw heads of two adjacent sets of screws 6. Multiple sets of shear pins 8 are spaced apart on the distribution circle where screw 6 is located. Specifically, screw 6 passes through the through holes of the lower spoke 2 and the upper spoke 4 and is screwed into the threaded hole of the gear 3 to realize the installation and connection between the gear ring 3 and the upper spoke 4 and the lower spoke 2. Two adjacent screws 6 share a double locking washer 7 to prevent the screws 6 from loosening. like Figure 5 As shown, the outer periphery of the shear pin 8 is provided with a raised arc structure, which is engaged in the chamfer of the pin hole on the contact surface of the lower spoke 2, the upper spoke 4 and the gear ring 3. Specifically, the shear pins 8 and screws 6 are arranged at intervals on the same distribution circle. The shear pins 8 transmit the torque between the gear and the spokes by bearing the shearing force. The shear pins 8 pass through the pin holes installed on the gear ring 3 and the lower spokes 2 and the upper spokes 4. The middle part has a raised arc structure, which is just stuck in the middle of the chamfer of the pin holes of the gear ring 3 and the lower spokes 2 and the upper spokes 4, which plays the role of axial limit and prevents the shear pins 8 from coming out during operation.

[0032] Through the above installation and connection methods, a large-sized double-spoke herringbone gear structure can be assembled. Compared with the traditional large-sized integrated spoke herringbone gear structure, the present invention realizes the separate design and processing of the herringbone gear gear ring and the spoke parts, which greatly reduces the difficulty of parts processing and manufacturing costs. In addition, the spoke parts are made of lightweight materials such as titanium alloy, making the overall weight of the gear lighter. Meanwhile, the gear spokes and gear ring connected together form a stable triangular support structure, which improves structural stability and can effectively improve the uneven load on both sides of the herringbone gear caused by system installation and manufacturing errors, thereby improving the smoothness of gear pair operation.

[0033] It should be noted that, as a further optimization of the above-described implementation method, the lower spoke 2 and the upper spoke 4 can adopt a not-completely symmetrical structural design, that is, they differ in spoke thickness, positional layout, hole shape, or positional characteristics. Although a symmetrical design of the upper and lower spokes is beneficial for mold versatility and reducing manufacturing costs, under specific working conditions, in addition to ensuring that the upper spoke 4, lower spoke 2, and gear ring 3 are assembled to form a stable triangular support structure, differentiated designs of the lower spoke 2 and upper spoke 4 are permitted to meet differentiated strength or stiffness requirements.

[0034] The structural design of each component of the double-spoke herringbone gear structure in this invention also needs to meet the following requirements: like Figure 6 As shown, the installation angle between the lower spoke 2 and the upper spoke 4 and the gear ring 3 is set to θ. The outer peripheral sidewall of the gear ring 3 is provided with a relief groove with a width of a. The tooth width of the gear ring 3 is set to b. The span between the two sets of mounting sides on the gear ring 3 is set to c. The installation height of the lower spoke 2 is set to d. The installation height of the upper spoke 4 is set to e. The flange thickness is set to f. Specifically, the width of the relief groove a and the tooth width b satisfy: a≤0.75b. By limiting the width of the relief groove, the tooth root strength is avoided. During the machining of the gear ring 3, sufficient space for the removal of the gear shaping or hobbing tools is ensured, while deformation caused by uneven cooling in the tooth width direction during heat treatment is avoided. Specifically, the span c satisfies: a+b≤c≤a+1.3b. When c=a+b, the shortest force flow path is formed, which reduces the bending moment of the gear ring by 25%. When the upper limit of c reaches a+1.3b, it ensures that the spoke support point covers the tooth width and the uniformity of contact stress distribution reaches more than 90%. Increasing the span c can improve the torsional stiffness.

[0035] Specifically, the lower spoke 2 and the upper spoke 4 are installed at the same height, i.e., d=e. The symmetrical support of the double spokes ensures a balanced load distribution. The flange thickness f satisfies: f=cde. The flange thickness f is used as the closed loop of the dimensional chain to ensure that the bolt preload is evenly distributed. After assembly, the compression deformation of each contact surface (flange-spoke-tooth ring) is consistent. The closed dimensional chain design allows the axial load to be transmitted linearly along the tooth ring-spoke-flange, reducing the bending moment component.

[0036] like Figure 7 As shown, the outer tooth surface g of the herringbone gear serves as the main working surface, used to transmit large load torques; Specifically, the outer tooth surface g serves as the main working surface. Due to its higher linear velocity, it has more tooth pairs engaged per unit time, resulting in a 20-30% increase in torque transmission capacity. This allows it to transmit torque for larger loads, making the load distribution more balanced.

[0037] like Figure 8 As shown, the meshing axial force borne by one side of the herringbone gear teeth is denoted as Fa, and the meshing radial force borne by one side of the herringbone gear teeth is denoted as Fr. Specifically, the design is based on the relationship between the installation angle and the force, ensuring that the installation angle θ, the meshing axial force Fa, and the meshing radial force Fr satisfy: θ≥arctan(Fr / Fa). During processing, the difference in thermal expansion between different materials can be compensated by the angle, facilitating the coordinated handling of thermal deformation. When θ=arctan(Fr / Fa), the spoke support force is collinear with the resultant force of Fa and Fr, which can eliminate the additional bending moment caused by radial separation. When θ>arctan(Fr / Fa), the installation angle margin design can cope with load fluctuations of ±20%.

[0038] In addition, the present invention provides a method for installing a double-spoke herringbone gear, including the herringbone gear structure described above, and further including the following installation steps: The gear shaft 1, lower spoke 2, upper spoke 4 and gear ring 3 are machined separately according to the design dimensions; The upper spoke 4 is attached to the upper flange of the gear shaft 1 by means of the loose bolt assembly 5, with the end away from the outer circle of the step. Insert the shear pin 8 into the pin hole of the upper spoke 4; Align the pin hole on the upper mounting edge of the gear ring 3 with the inserted shear pin 8, so that it connects with the stepped outer circle of the upper spoke plate 4. The double locking washer 7 is fitted with the loose screw 6 and inserted into the through hole on the upper spoke plate 4 and the gear ring 3; The lower spoke 2 is attached to the lower side of the flange of the gear shaft 1 by means of the loose bolt assembly 5, with the end away from the outer circle of the step. Insert the shear pin 8 into the pin hole of the lower spoke 2; Align the pin hole on the lower mounting edge of the gear ring 3 with the inserted shear pin 8, so that it connects with the stepped outer circle of the lower spoke 2. Insert the double locking washer 7 into the through hole on the lower spoke 2 and the gear ring 3, matching the loose screw 6; Tighten the bolt assembly 5 and screw 6 in sequence to form a stable triangular support structure with the lower spoke 2, the upper spoke 4 and the gear ring 3.

[0039] It should be noted that during gear installation, the assembly order of the two sets of spokes can be adjusted as needed. In the above installation steps, the upper spoke 4 is assembled first, followed by the lower spoke 2. In actual installation, the lower spoke 2 can also be assembled first, followed by the upper spoke 4.

[0040] Through the above structural design, after the gear spokes, gear ring and shaft are separated, they do not need to be machined, carburized and quenched together with the gear ring. The gear shaft 1, lower spoke 2, upper spoke 4 and gear ring 3 of the present invention can be processed separately. The upper and lower mounting edge span c of the gear ring 3, the mounting height e of the lower spoke 2 and the mounting height e of the upper spoke 4 are pre-processed as finishing dimensions. The mounting flange thickness f of the gear shaft 1 is matched with dimensions c, d and e in the assembly assembly as a dimension chain closed loop. It is more convenient to set up machining auxiliary support fixtures and heat treatment clamping fixtures during processing. The deformation of gear teeth during grinding, carburizing and quenching is easier to control, which is conducive to improving the overall machining accuracy of the gear, improving the uniformity of the surface carburized layer of the gear, and improving the service life of the gear. In addition, as a key moving component in aerospace transmission, the manufacturing cost of such large herringbone gears accounts for a high proportion of the total cost of the reducer. By separating the shaft, gear ring, and spokes, if the tooth surface is damaged during use, the gear ring can be replaced separately, while the spokes and shaft can still be reused, which greatly reduces the maintenance cost of the reducer and improves its economic efficiency.

[0041] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-webbed herringbone gear structure, characterized by, The gear structure comprises a gear shaft (1), a lower spoke plate (2) and an upper spoke plate (4), and a gear ring (3). The outer periphery of the gear shaft (1) is integrally formed with a flange. The lower spoke plate (2) and the upper spoke plate (4) are provided with stepped outer circles at the ends away from the gear shaft (1), and the top of the stepped outer circles is annularly arranged with through holes and pin holes. The inner side wall of the gear ring (3) is integrally formed with two groups of mounting edges, and the top of the two groups of mounting edges is annularly arranged with threaded holes and pin holes. The lower spoke plate (2) and the upper spoke plate (4) are symmetrically arranged on both sides of the flange at the end close to the gear shaft (1) and are connected with the flange through a bolt assembly (5), and the two groups of mounting edges of the gear ring (3) are connected with the stepped outer circles on the lower spoke plate (2) and the upper spoke plate (4) through screws (6).

2. The double-webbed herringbone gear structure according to claim 1, characterized in that: The gear structure further comprises a shear pin (8), and a plurality of groups of shear pins (8) are arranged on the distribution circle where the screw (6) is located and are penetrated and mounted in the pin holes on the gear ring (3), the lower spoke plate (2) and the upper spoke plate (4).

3. The double-webbed herringbone gear structure according to claim 2, characterized in that: The outer periphery of the shear pin (8) is provided with a convex arc structure in the middle, and the arc structure is clamped in the chamfer of the pin hole on the contact surface of the lower spoke plate (2), the upper spoke plate (4) and the gear ring (3).

4. The double-webbed herringbone gear structure according to claim 1, characterized in that: The bolt in the bolt assembly (5) is in clearance fit with the connecting holes of the flange, the lower spoke plate (2) and the upper spoke plate (4).

5. The double-webbed herringbone gear structure according to claim 1, characterized in that: The screw (6) is penetrated in the through hole and is in threaded connection with the threaded hole, and the bottom of the nail cap of two adjacent screws (6) is provided with a group of double locking washers (7).

6. The double-webbed herringbone gear structure according to claim 1, characterized in that: The gear ring (3) is made of gear steel material, and the lower spoke plate (2) and the upper spoke plate (4) are made of titanium alloy or composite material.

7. The double-webbed herringbone gear structure according to claim 1, wherein: The outer periphery side wall of the gear ring (3) is provided with a tool withdrawal groove, and the width a of the tool withdrawal groove satisfies a≤αb. The span c between the two groups of mounting edges of the gear ring (3) satisfies a+b≤c≤a+λb. Wherein, b is the tooth width of the gear ring (3). α is a preset value, and is 0.75; λ is a preset value, and is 1.

3.

8. The double-webbed herringbone gear structure of claim 1, wherein: The installation heights of the lower spoke plate (2) and the upper spoke plate (4) are equal, and the thickness f of the flange on the gear shaft (1) satisfies f=c-d-e. Wherein, d is the installation height of the lower spoke plate (2), and e is the installation height of the upper spoke plate (4).

9. The double-webbed herringbone gear structure of claim 1, wherein: The installation angle θ of the lower spoke plate (2) and the upper spoke plate (4) with the gear ring (3) satisfies θ≥arctan(Fr / Fa). Wherein, Fa is the meshing axial force borne by a single side gear tooth of the double helical gear, and Fr is the meshing radial force borne by a single side gear tooth of the double helical gear.

10. A method of mounting a double-webbed herringbone gear, characterized in that: The gear structure comprises a gear shaft (1), a lower spoke plate (2) and an upper spoke plate (4), and a gear ring (3). The gear shaft (1), the lower spoke plate (2), the upper spoke plate (4) and the gear ring (3) are separately machined according to the design size. The end of the upper spoke plate (4) away from the stepped outer circle is overlapped on the upper side of the flange of the gear shaft (1) through the bolt assembly (5) which is not locked. The shear pin (8) is mounted in the pin hole of the upper spoke plate (4). The pin hole on the upper side mounting edge of the gear ring (3) is aligned with the mounted shear pin (8) to connect the stepped outer circle of the upper spoke plate (4). The gear structure comprises a gear shaft (1), a lower spoke plate (2) and an upper spoke plate (4), and a gear ring (3). The double locking washer (7) is matched with the non-locking screw (6) and is installed into the through hole on the upper spoke plate (4) and the gear ring (3); The lower spoke plate (2) is overlapped on the flange lower side of the gear shaft (1) through the non-locking bolt assembly (5) from the end of the stepped outer circle; The shear pin (8) is installed into the pin hole of the lower spoke plate (2); The pin hole on the lower side of the installation edge of the gear ring (3) is aligned with the installed shear pin (8) to be connected with the stepped outer circle of the lower spoke plate (2); The double locking washer (7) is matched with the non-locking screw (6) and is installed into the through hole on the lower spoke plate (2) and the gear ring (3); The bolt assembly (5) and the screw (6) are locked in sequence, so that the lower spoke plate (2), the upper spoke plate (4) and the gear ring (3) form a stable triangular support structure.

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