Design method of multi-cone clutch friction pair of high-speed heavy-load unmanned equipment

Abstract

The invention relates to a design method of a multi-cone clutch friction pair of high-speed heavy-load unmanned equipment. The design method comprises the following steps: determining working environment characteristics and design indexes of the multi-cone clutch friction pair; based on working environment characteristics and specific design indexes, a multi-cone clutch friction pair is designed; wherein the step of designing the multi-cone clutch friction pair comprises the sub-steps of determining a cone tooth arrangement form of the multi-cone clutch friction pair, determining cone tooth configuration parameters of the multi-cone clutch friction pair, and designing groove characteristics of the multi-cone clutch friction pair; and checking preset parameters of the friction pair of the multi-cone clutch to complete the design of the multi-cone clutch. According to the method, a multi-cone clutch friction pair is designed based on the requirement of a high-speed unmanned platform transmission system clutch, the maximum torque of the friction pair is checked by adopting a theoretical torque calculation formula, and the stress and temperature of the multi-cone clutch are checked after the maximum torque meets the requirement; and the comprehensive multi-cone clutch design covering parameter design, multi-physics field checking and heat dissipation optimization is completed.

Description

Technical Field

[0001] The present invention relates to the technical field of clutches, and in particular to a design method for a multi-cone clutch friction pair of high-speed and heavy-load unmanned equipment. Background Art

[0002] As unmanned equipment rapidly develops toward higher speeds, heavier loads, and intelligent capabilities, transmission systems face increasingly demanding operating conditions. High-speed, heavy-loaded unmanned equipment, such as unmanned combat vehicles and heavy-duty drones, requires efficient power transmission at high speeds and torques, while also meeting high reliability and low maintenance requirements under unmanned operation. The clutch, a core component of the transmission system, connects and disconnects the engine and transmission, controls power transfer, prevents overload, and, to a certain extent, absorbs vibration, shock, and noise. Its performance directly determines the equipment's power response, transmission efficiency, and mission sustainability.

[0003] Currently, high-speed, heavy-load, and unmanned vehicles mostly utilize traditional multi-plate wet clutches, which increase torque capacity by increasing the number of friction pairs. However, in high-speed, heavy-load, and unmanned scenarios, these clutches exhibit significant drawbacks, primarily manifesting in poor high-speed adaptability, insufficient heavy-load capacity, low structural redundancy and power density, and delayed dynamic response. As a key component in vehicle compound transmission systems, the multi-cone clutch, with its unique structure, offers an effective solution to the high-torque transmission challenges of wet multi-plate clutches. Its radially arranged tapered friction surfaces increase the contact area between the friction pairs, effectively utilizing the friction area. While maintaining the same performance output, the cone clutch significantly reduces the space required, enabling integration into more compact mechanical designs and achieving higher power density. Furthermore, due to the wedge action of the tapered friction surfaces, the normal pressure on the friction surfaces of the cone clutch is greater than the axial force, generating greater contact force within a smaller space and achieving higher torque transmission capacity. Conventional friction clutches, when subjected to high loads, can experience axial deformation of the friction plates, leading to uneven contact and failure. The multi-cone clutch can limit the axial compression deformation by increasing the thickness of the friction pair, significantly improving the clutch's load-bearing capacity and durability, and ensuring good power transmission performance. Therefore, the multi-cone clutch provides effective support for high-power density, high-speed, heavy-load unmanned equipment transmission systems. In previous studies, domestic and foreign scholars focused on proposing different configurations of multi-cone clutches, such as: a one-stage oil cylinder multi-cone dual clutch configuration; and an annular V-groove clutch configuration. However, no scholar has systematically proposed a design method for multi-cone clutch friction pairs of different configurations suitable for different working conditions to achieve a coordinated optimization design of the clutch's axial compactness, high torque transmission capacity and low thermal load. Summary of the Invention

[0004] The purpose of the present invention is to propose a design method for a multi-cone clutch friction pair for high-speed and heavy-load unmanned equipment to solve the problems existing in the above-mentioned prior art. Based on the clutch requirements of the high-speed and heavy-load unmanned platform transmission system, the present invention designs a multi-cone clutch friction pair and uses a theoretical torque calculation formula to calibrate the maximum torque of the friction pair. After meeting the requirements, the stress and temperature of the multi-cone clutch are calibrated to complete a comprehensive multi-cone clutch design covering parameter design, multi-physical field calibration and heat dissipation optimization.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A design method for a multi-cone clutch friction pair for high-speed and heavy-load unmanned equipment, comprising:

[0007] Determine the working environment characteristics and design indicators of the multi-cone clutch friction pair;

[0008] Based on the working environment characteristics and specific design indicators, the multi-cone clutch friction pair is designed; wherein, the design of the multi-cone clutch friction pair includes: determining the arrangement form of the bevel teeth of the multi-cone clutch friction pair, determining the configuration parameters of the bevel teeth of the multi-cone clutch friction pair, and designing the groove characteristics of the multi-cone clutch friction pair;

[0009] The designed multi-cone clutch friction pair is calibrated with preset parameters to complete the final design of the multi-cone clutch friction pair.

[0010] Optionally, the working environment characteristics of the multi-cone clutch friction pair include: high load and low speed working condition, medium-high load and medium-high speed working condition, and low load and high speed working condition;

[0011] The design indicators of the multi-cone clutch friction pair include: inner diameter of the friction pair, outer diameter of the friction pair, minimum transmission torque of the friction pair, and separation axial dimension of the friction pair.

[0012] Optionally, determining the arrangement of the bevel teeth of the friction pair of the multi-cone clutch includes:

[0013] In high load and low speed working conditions, radially symmetrical bevel gear arrangement is adopted;

[0014] In medium to high load and medium speed conditions, a radial asymmetric bevel gear arrangement is adopted;

[0015] Under low load and high speed conditions, non-uniform bevel gear arrangement is adopted.

[0016] Optionally, determining the configuration parameters of the multi-cone clutch friction pair bevel teeth includes:

[0017] Determine the cone tooth type, cone tooth angle, cone tooth height, and number of cone surfaces of the multi-cone clutch friction pair.

[0018] Optionally, determining the bevel gear type includes:

[0019] The bevel gear types are divided into two types: trapezoidal bevel gears and arcuate bevel gears. The trapezoidal bevel gears are used in clutches with stable loads and long-term continuous operation, while the arcuate bevel gears are used in clutches with short-term impact loads and high peak torque requirements.

[0020] The trapezoidal bevel gear is determined based on the bevel gear angle, cone height, and cone top distance; the arc-shaped bevel gear is determined based on the bevel gear radius, cone height, cone top distance, and arc radial difference;

[0021] The bevel gear angle is designed based on a preset empirical threshold;

[0022] The height of the bevel gear is:

[0023]

[0024] Among them, h c is the circumferential groove depth, h z is the thickness of the dual steel sheet, H cspr It is the axial dimension of the friction pair separation;

[0025] For the multi-cone clutch friction pair with radially symmetrical bevel gear arrangement and radially asymmetrical bevel gear arrangement, the number of cone surfaces is:

[0026]

[0027] Among them, the inner diameter R of the friction pair i , outer diameter R of friction pair o , c is the empirical parameter;

[0028] For the friction pair of a multi-cone clutch with non-uniform bevel gear arrangement, the number of cone surfaces is:

[0029]

[0030] Optionally, designing the multi-cone clutch friction pair groove features includes:

[0031] Two types of oil grooves are provided: circumferential grooves and radial grooves, both of which have rectangular cross-sections;

[0032] The circumferential groove is arranged on the tooth top surface of the multi-cone bevel gear. The groove width is the same as the distance from the cone top, and the groove depth is the preset cone height value.

[0033] The radial groove is a through groove that passes through the inner and outer diameters. The number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement, radially asymmetrical bevel gear arrangement, and non-uniform bevel gear arrangement is different; and the number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement, and the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with non-uniform bevel gear arrangement; the depth of the radial groove has the ability to connect the oil chambers of each circumferential groove, and the radial groove depth should be the sum of the bevel gear height and the circumferential groove height.

[0034] Optionally, performing preset parameter verification on the designed multi-cone clutch friction pair includes:

[0035] Check the torque parameters of the multi-cone clutch friction pair;

[0036] Check the stress parameters of the multi-cone clutch friction pair;

[0037] The maximum temperature of the multi-cone clutch friction pair is checked.

[0038] Optionally, checking the torque parameters of the multi-cone clutch friction pair includes:

[0039] Calculate the maximum friction torque transmitted by each bevel gear;

[0040] Calculate the sum of the maximum friction torque of all bevel gears;

[0041] The maximum friction torque sum is compared with the design index of the multi-cone clutch friction pair to determine whether it meets the index.

[0042] Optionally, checking the stress parameters of the multi-cone clutch friction pair includes:

[0043] Check the stress of the bevel gear part; the bevel gear part includes: normal stress generated by extrusion and torsional shear stress generated by friction torque;

[0044] Check the stress of the friction pair.

[0045] Optionally, checking the maximum temperature of the multi-cone clutch friction pair includes:

[0046] Based on a disc friction pair with the same inner and outer diameters as the multi-cone friction pair, the clutch engagement process parameters are introduced into the disc friction pair temperature field calculation model to obtain the maximum temperature of the disc friction pair. The maximum temperature of the multi-cone friction pair is obtained using an empirical formula.

[0047] Compare the maximum temperature of the multi-cone friction pair with the maximum temperature limit to determine whether it meets the working condition requirements.

[0048] The beneficial effects of the present invention are:

[0049] The present invention proposes a multi-cone clutch design method covering parameter design and multi-physical field verification, which enables the multi-cone clutch to transmit large torque in a limited space, and uses stress verification and temperature verification to help improve the service life of the multi-cone friction pair.

[0050] The correlation between the configuration parameters such as the arrangement shape of multi-conical bevel gears, bevel gear height, bevel gear angle, groove characteristics and the stress and temperature rise characteristics of multi-conical friction pairs was analyzed, which comprehensively guided the design of multi-conical friction pairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 Schematic diagram of the friction pair of a multi-plate wet clutch (left) and a multi-cone clutch (right);

[0053] Figure 2 Schematic diagram of friction pair arrangement of radially symmetrical bevel gears according to an embodiment of the present invention;

[0054] Figure 3 Schematic diagram of a friction pair arrangement of radially asymmetric bevel gears according to an embodiment of the present invention;

[0055] Figure 4 Schematic diagram of the friction pair with non-uniform bevel gear arrangement (top) and top view of the friction plate (bottom) according to an embodiment of the present invention;

[0056] Figure 5 The basic parameters of the arc-shaped and trapezoidal bevel gears according to the embodiment of the present invention;

[0057] Figure 6 Schematic diagram of the arrangement of radial grooves (left) and circumferential grooves (right) according to an embodiment of the present invention;

[0058] Figure 7 A simplified diagram of the asymmetric friction plate pressure (left) and a schematic diagram of the maximum shear stress verification section (right) according to an embodiment of the present invention are shown;

[0059] Figure 8 The present invention is a flowchart of a method for designing a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0061] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] like Figure 1 As shown, the friction pair of a conventional flat multi-plate wet clutch consists of multiple pairs of alternating friction plates and steel plates. Given the same inner and outer diameters, this friction pair has a larger axial dimension, which does not meet the requirements of a high-power density structure. A multi-cone clutch is a type of wet friction clutch. Its core component is a multi-cone friction pair. Unlike a flat multi-plate wet clutch, this friction pair features a multi-cone arrangement with multiple radially arranged conical friction surfaces, increasing the contact area between the friction pairs and ensuring efficient use of the friction area. This results in a smaller axial dimension than a flat multi-plate wet clutch.

[0063] During the working process of the multi-cone clutch, the power of the engine is transmitted by the friction principle. It is mainly composed of a pressure plate, a multi-cone friction pair, a clutch spline hub, a clutch piston and a clutch cylinder liner. The clutch spline hub is fixed on the clutch input shaft and rotates synchronously with the input shaft; the multi-cone clutch friction pair is located between the clutch piston and the pressure plate, wherein the multi-cone friction plate is connected to the clutch spline hub, and the multi-cone dual steel plate is connected to the clutch cylinder liner. The clutch piston is connected to the clutch cylinder liner through a series of return springs and spring brackets. When the clutch pedal is stepped on, the return spring pushes the clutch piston to move backward, separating the clutch plate from the dual steel plate. At this time, when the clutch is in the disengaged state, the clutch spline hub cannot drive the clutch cylinder liner to rotate; when in the engaged state, the oil pressure is controlled to make the clutch piston move forward and cooperate with the pressure plate to tighten the multi-cone friction plate and the dual steel plate to generate friction, thereby driving the clutch cylinder liner to rotate, thereby realizing power transmission.

[0064] Because multi-cone clutches are wet friction clutches, the design methods for key components such as the clutch piston and clutch cylinder liner are the same as those for wet multi-plate clutches. However, the design method for the multi-cone friction pair, a core component of the multi-cone clutch, has never been explored. Therefore, a design method for the multi-cone clutch friction pair is proposed to improve multi-cone clutch design.

[0065] like Figure 8 As shown, this embodiment proposes a design method for a multi-cone clutch friction pair for high-speed and heavy-load unmanned equipment, including:

[0066] Determine the working environment characteristics and design indicators of the multi-cone clutch friction pair;

[0067] Based on the working environment characteristics and specific design indicators, the multi-cone clutch friction pair is designed. The design of the multi-cone clutch friction pair includes: determining the arrangement of the bevel teeth of the multi-cone clutch friction pair, determining the configuration parameters of the bevel teeth of the multi-cone clutch friction pair, and designing the groove characteristics of the multi-cone clutch friction pair.

[0068] The designed multi-cone clutch friction pair is calibrated with preset parameters to complete the final design of the multi-cone clutch friction pair.

[0069] Specifically, in this embodiment, first, the specific design indicators and working environment characteristics of the multi-cone clutch friction pair are clarified, and the selected material for the friction pair is determined; secondly, based on the working environment characteristics of the multi-cone friction pair, friction pairs with different bevel tooth arrangements are selected, and the configuration parameters of the bevel tooth part and the groove characteristics of the friction pair are designed based on the specific design indicators; then, based on the design of the multi-cone friction pair, the maximum transmission torque of the friction pair is calculated to determine whether it meets the requirements; then, the allowable stress of the friction plate is clarified, and based on the design of the multi-cone friction pair, the stress of the bevel tooth part of the friction pair and the stress of the friction pair part are checked respectively; finally, the maximum temperature limit of the friction pair is clarified, and based on the design of the multi-cone friction pair, the maximum temperature rise of the friction pair is checked to determine whether it meets the working requirements.

[0070] Specifically, in this embodiment, the working environment characteristics of the multi-cone friction pair can be divided into three categories: high load and low speed, medium-high load and medium-high speed, and low load and high speed; the specific design indicators of the multi-cone friction pair mainly include four characteristics: the inner diameter R of the friction pair i , outer diameter R of friction pair o , the minimum transmission torque T of the friction pair fc , the friction pair separation axial dimension H cspr .

[0071] Furthermore, determining the arrangement of the bevel teeth of the friction pair of the multi-cone clutch includes:

[0072] In high load and low speed working conditions, radially symmetrical bevel gear arrangement is adopted;

[0073] In medium to high load and medium speed conditions, a radial asymmetric bevel gear arrangement is adopted;

[0074] Under low load and high speed conditions, non-uniform bevel gear arrangement is adopted.

[0075] Specifically, in this embodiment, the arrangement of the bevel teeth of the multi-conical friction pair is determined as follows:

[0076] The arrangement of multi-conical friction pair bevel gears can be divided into three types:

[0077] like Figure 2 The symmetrical arrangement of the bevel gears shown has high load distribution and dynamic balance, which helps to reduce the impact in the direction of rotation. The structure is simple and easy to process. However, under long-term high-load conditions, there will be a high risk of local overheating. It is suitable for high-load and low-speed conditions.

[0078] like Figure 3 The asymmetric layout of the friction pair with asymmetric arrangement of bevel gears shown can optimize the uniformity of heat distribution and improve the concentration of friction heat, and is suitable for medium to high load and medium to high speed working conditions.

[0079] like Figure 4 The non-uniform bevel gear arrangement shown here offers the potential for even heat dissipation. The outer and inner cones are connected by multiple connecting plates, making them suitable for low-load, high-speed operating conditions. A schematic diagram of the friction pair with a non-uniform bevel gear arrangement (top) and a top view of the friction plate (bottom) are shown.

[0080] Furthermore, determining the configuration parameters of the multi-cone clutch friction pair bevel teeth includes:

[0081] Determine the cone tooth type, cone tooth angle, cone tooth height, and number of cone surfaces of the multi-cone clutch friction pair.

[0082] Specifically, in this embodiment, the configuration parameters of the multi-conical friction pair bevel gear are determined as follows:

[0083] There are four basic characteristics of bevel gear configuration parameters, namely bevel gear type, bevel gear angle, bevel gear height, and number of bevel surfaces.

[0084] The multi-cone bevel gear types can be divided into two types: arc-shaped and trapezoidal. Figure 5 As shown in the figure, trapezoidal bevel gears experience less internal stress during operation and transmit less torque, making them suitable for clutches with stable loads and long-term continuous operation. Arc-shaped bevel gears experience greater internal stress during operation and transmit slightly greater torque than trapezoidal bevel gears, making them suitable for clutches with short-term impact loads and high peak torque requirements. Trapezoidal bevel gears are defined by three basic parameters: the bevel angle α, the cone height h, and the cone-top distance S. Arc-shaped bevel gears are defined by four basic parameters: the cone radius r, the cone height h, the cone-top distance S, and the arc radial difference δ.

[0085] Since the same-configuration bevel teeth with the same bevel angle and height are evenly arranged on the friction pair, the bevel tooth top distance is automatically determined after the bevel angle, height, and number of cone surfaces are determined, and no additional determination formula is required. In the design of arc-shaped bevel teeth, the arc radial difference and the bevel radius must be determined after the design of the bevel angle, height, and number of cone surfaces. The arc radial difference δ of the arc-shaped bevel teeth can be determined by the bevel angle and height. The formula is:

[0086]

[0087] The radius R of the arc-shaped bevel gear can be determined by the radial difference of the arc-shaped bevel gear and the height of the bevel gear. The empirical design formula is:

[0088]

[0089] The distance between the cone tops of arc-shaped bevel gears is the same as that of trapezoidal bevel gears and is automatically determined.

[0090] After determining the bevel gear type, the other three basic bevel gear characteristics need to consider the specific design indicators of the multi-conical friction pair and the inner diameter R of the friction pair. i , outer diameter R of friction pair o , the minimum transmission torque T of the friction pair fc , the friction pair separation axial dimension H cspr conduct.

[0091] The empirical value of the bevel gear angle α is 20°≤α≤35°.

[0092] The design formula for the cone tooth height is:

[0093]

[0094] In the above formula, h c is the circumferential groove depth, h z is the thickness of the dual steel sheet.

[0095] For symmetrical and asymmetrical structures, the empirical design formula for the number of cones n is:

[0096]

[0097] In the above formula, c is an empirical parameter, ranging from 2.6 to 3.0, and the number of cones n is an integer.

[0098] For non-uniform structures, the design of the number of cone surfaces can be divided into the design of the number of outer cone surfaces and the design of the number of inner cone surfaces. The number of outer cone surfaces is 4, and the empirical formula for the number of inner cone surfaces is:

[0099]

[0100] The empirical parameter c can be 2.5 to .7.

[0101] Furthermore, the design of the multi-cone clutch friction pair groove features includes:

[0102] Two types of oil grooves are provided: circumferential grooves and radial grooves, both of which have rectangular cross-sections;

[0103] The circumferential groove is arranged on the tooth top surface of the multi-cone bevel gear. The groove width is the same as the distance from the cone top, and the groove depth is the preset cone height value.

[0104] The radial groove is a through groove that passes through the inner and outer diameters. The number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement, radially asymmetrical bevel gear arrangement, and non-uniform bevel gear arrangement is different; and the number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement, and the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with non-uniform bevel gear arrangement; the depth of the radial groove has the ability to connect the oil chambers of each circumferential groove, and the radial groove depth should be the sum of the bevel gear height and the circumferential groove height.

[0105] Specifically, in this embodiment, the friction pair groove features are designed as follows:

[0106] For multi-cone friction pairs, two types of oil grooves can be set: circumferential grooves and radial grooves, and both have rectangular cross-sections. Figure 6 Shown is a schematic diagram of the arrangement of radial grooves (left) and circumferential grooves (right).

[0107] The circumferential groove is arranged on the top surface of the multi-cone bevel gear. Its groove width is the same as the distance S from the top of the cone, and its groove depth h c It is 2 / 3 of the cone height h.

[0108] The radial groove is a through groove that passes through the inner and outer diameters, and the number of its arrangement is n j For a symmetrical bevel gear arrangement, n j Take 12; for asymmetric bevel gear arrangement, n j Take 10; for non-uniform bevel gear arrangement, n j Take 8. The depth of the radial groove should be able to connect the oil chambers of each circumferential groove. Its depth should be the sum of the height of the bevel gear and the height of the circumferential groove. The width of the radial groove should be 2mm.

[0109] The overall design of the multi-conical friction pair is obtained by combining the three points.

[0110] Furthermore, the preset parameters of the designed multi-cone clutch friction pair are checked including:

[0111] Check the torque parameters of the multi-cone clutch friction pair;

[0112] Check the stress parameters of the multi-cone clutch friction pair;

[0113] The maximum temperature of the multi-cone clutch friction pair is checked.

[0114] Furthermore, the torque parameter calibration of the multi-cone clutch friction pair includes:

[0115] Calculate the maximum friction torque transmitted by each bevel gear;

[0116] Calculate the sum of the maximum friction torque of all bevel gears;

[0117] Compare the sum of the maximum friction torques with the design index of the multi-cone clutch friction pair to determine whether they meet the index.

[0118] Specifically, in this embodiment, the torque parameter verification method of the multi-cone friction pair is as follows:

[0119] Calculate the maximum friction torque transmitted by each bevel gear:

[0120] The torque calculation methods of a single bevel gear can be divided into two types: trapezoidal bevel gear calculation method and arc bevel gear calculation method.

[0121] For trapezoidal bevel gears, a single trapezoidal bevel gear consists of two inclined friction surfaces. The torque on a single friction surface can be calculated by the following formula:

[0122]

[0123] In the above formula, A ct is the total contact area of the multi-conical friction pair of trapezoidal bevel gears, A (i) is the contact area of a single cone surface, n is the number of contact surfaces of the multi-cone friction pair bevel gears, R (i) is the outer diameter of the i-th cone, r (i) is the inner diameter of the i-th cone.

[0124]

[0125] In the above formula, p ct is the actual contact pressure of the trapezoidal bevel gear multi-cone friction pair, F ct is the loading pressure of the multi-conical friction pair of trapezoidal bevel gear, then the friction torque M on a single friction surface of the trapezoidal bevel gear is ct(i) It can be expressed as:

[0126]

[0127] For arc-shaped bevel gears, a single bevel gear consists of two arc-shaped friction surfaces. The torque on a single friction surface can be calculated by the following formula:

[0128]

[0129] In the above formula, A ca is the total contact area of the arc-shaped bevel gear multi-cone friction pair, R is the radius of the arc-shaped bevel gear, and R0 is the radius of the arc-shaped bevel gear center.

[0130] The actual contact pressure of the arc-shaped bevel gear multi-cone friction pair is a function of the radius r:

[0131]

[0132] Therefore, the friction torque M on a single friction surface of the arc-shaped bevel gear isca (i) can be expressed as:

[0133]

[0134] Calculate the total friction torque of all bevel gears:

[0135] For a multi-conical friction pair, the total torque transmitted is the sum of the torques transferred by all friction surfaces. The total torque can be expressed as:

[0136]

[0137] In the above formula, Z c is the number of multi-cone friction pairs, based on the multi-cone friction pair structure, Z c = 2. k is the correction coefficient of friction torque of the friction pair, and k is taken as 0.75~0.85.

[0138] For a multi-conical friction pair, its axial dimension at separation can be expressed as:

[0139] L c =δ s1 +δ f +δ s2 +2δ h (1.11)

[0140] In the above formula, δ s1 and δ s2 are the thickness of the upper and lower multi-conical steel sheets respectively; δ f is the thickness of the multi-conical friction plate; δ h is the separation gap of the multi-conical friction pair, take δ h Equal to the cone tooth height h.

[0141] Compare the calculated results with the specific design indicators of the multi-cone friction pair to determine whether they meet the indicators.

[0142] Furthermore, the stress parameters of the multi-cone clutch friction pair are checked including:

[0143] Check the stress of the bevel gear part; the bevel gear part includes: normal stress generated by extrusion and torsional shear stress generated by friction torque;

[0144] Check the stress of the friction pair.

[0145] Specifically, in this embodiment, the friction pair stress verification method is:

[0146] Stress check of bevel gear:

[0147] The bevel gear part is mainly composed of the normal stress generated by extrusion and the torsional shear stress generated by friction torque. These two stresses are checked.

[0148] The normal stress of the bevel gear is numerically equal to the pressure on the contact surface, and its direction is consistent with the normal direction of the cone surface. The average normal stress of the trapezoidal and arc-shaped bevel gears can be obtained by combining formulas (1.4) and (1.5), and formulas (1.7) and (1.8), respectively. The maximum normal stress σ max The calculation method is:

[0149]

[0150] m=3·cos(α)(1.13)

[0151] In the above formula, m is the stress concentration factor. After calculation, σ max Compare with [σ] to determine whether it meets the work requirements.

[0152] The maximum torsional shear stress of the bevel gear occurs at the root of the bevel gear, so only that part needs to be checked. For multi-cone bevel gears with the same bevel height and bevel angle but different bevel radii, the shear stress at the root is the same. Therefore, for bevel gears with the same characteristics, one tooth can be selected as a representative for verification. The verification method is as follows:

[0153]

[0154] In the above formula, R0 is the inner diameter of the selected bevel tooth surface, R is the outer diameter of the selected bevel tooth surface, and S is the tooth top distance. After calculation, substitute the above formula into:

[0155]

[0156] Where Mc is the friction torque of the selected bevel tooth surface, which can be obtained by formula (1.9) or formula (1.6). The calculated shear stress value is compared with the allowable shear stress to determine whether failure occurs.

[0157] Friction pair stress check:

[0158] The friction plate is the part of the friction pair that is subjected to the most complex stress, so only the stress check of the friction plate is required.

[0159] Among the three bevel gear arrangement configurations, only the asymmetrically distributed friction plate of the bevel gear needs to be checked. The checking method is as follows:

[0160] like Figure 7 As shown, the conical teeth of the friction plate are simplified, the radius of the midpoint of the tooth root is regarded as the pressure application point, and the double cone surfaces on any two sides of the friction plate are selected as the maximum shear stress verification section for shear stress verification. Figure 7 Schematic diagram of the simplified asymmetric friction plate pressure (left) and the maximum shear stress verification section (right).

[0161] The maximum shear stress will occur at F ct With Fz At the midpoint radius of the action point, the shear stress verification formula is:

[0162]

[0163] In the above formula, A is F ct With F z The cross-sectional area of the friction plate at the midpoint radius of the action point, p c is the pressure on the tooth surface of a single bevel gear, A (i) is the tooth surface area of a single bevel gear. After the calculation is completed, the maximum shear stress is compared with the allowable shear stress to determine whether there is failure.

[0164] Furthermore, the maximum temperature of the multi-cone clutch friction pair is checked including:

[0165] Based on a disc friction pair with the same inner and outer diameters as the multi-cone friction pair, the clutch engagement process parameters are introduced into the disc friction pair temperature field calculation model to obtain the maximum temperature of the disc friction pair. The maximum temperature of the multi-cone friction pair is obtained using an empirical formula.

[0166] Compare the maximum temperature of the multi-cone friction pair with the maximum temperature limit to determine whether it meets the working condition requirements.

[0167] Specifically, in this embodiment, the method for verifying the maximum temperature rise of the friction pair is:

[0168] Based on the disc friction pair with the same inner and outer diameters as the multi-cone friction pair, the parameters of the clutch engagement process are introduced into the disc friction pair temperature field calculation model to obtain the maximum temperature T of the disc friction pair. p , the maximum temperature T of the multi-cone friction pair is obtained using the empirical formula c :

[0169]

[0170] In the above formula, t is the friction pair engagement time, α is the bevel angle. The maximum temperature T c Compare with the maximum temperature limit T to determine whether it meets the working conditions.

[0171] In order to make the features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific embodiments.

[0172] Step 1. Define the specific design indicators and working environment characteristics of the multi-cone clutch friction pair and determine the selected materials for the friction pair.

[0173] Step 2. Select friction pairs with different bevel gear arrangements based on the working environment characteristics of multi-conical friction pairs, design the configuration parameters of the bevel gear parts based on specific design indicators, and design the groove characteristics of the friction pairs.

[0174] Step 3. Based on the design of the multi-conical friction pair, calculate the maximum transmission torque of the friction pair and determine whether it meets the requirements.

[0175] Step 4. Clarify the allowable stress of the friction plate. Based on the multi-conical friction pair design, check the stress of the friction pair cone teeth and the stress of the friction pair separately.

[0176] Step 5. Determine the maximum temperature limit of the friction pair. Based on the multi-conical friction pair design, check the maximum temperature rise of the friction pair to determine whether it meets the working requirements.

[0177] In this embodiment, the materials selected for the multi-cone clutch friction pair in step 1 are: the multi-cone friction plate is made of copper alloy, and the multi-cone dual steel plate is made of 30Cr. The multi-cone friction pair needs to be used in medium-to-high load and medium-to-high speed working conditions. The specific design indicators are shown in Table 1 below:

[0178] Table 1

[0179]

[0180] In step 2, based on the fact that the applicable working conditions of the friction pair are medium to high load and medium to high speed conditions, an asymmetric bevel gear arrangement structure is selected.

[0181] The designed clutch requires stable load and long-term continuous operation. The bevel gear type is determined to be trapezoidal bevel gear. The empirical value of the bevel gear angle α is 25°≤α≤35°. The cone angle is set to α=26.268°.

[0182] The design formula for the cone tooth height is:

[0183]

[0184] In the above formula, h c is the circumferential groove depth, h z The thickness of the dual steel sheet is 4mm, the depth of the circumferential groove is 1mm, so the design size of the cone height is 1.5mm.

[0185] For symmetrical and asymmetrical structures, the empirical design formula for the number of cones n is:

[0186]

[0187] In the above formula, c is an empirical parameter, which is 2.6 to 3.0. The number of cones n is an integer. The inner and outer diameters are substituted, and the number of n cones is 13. The inner and outer diameters of the friction pair are combined to make the cones evenly arranged on the ring. The cone top distance is set to S = 2.7 mm.

[0188] The circumferential groove is arranged on the top surface of the multi-cone bevel gear. Its groove width is the same as the distance S from the top of the cone, and its groove depth h c It is 2 / 3 of the cone height h, that is, the groove depth is 1mm,

[0189] For asymmetric bevel gear arrangement, the number of radial grooves n j Take 10, and arrange them evenly on the friction pair. Its depth should be the sum of the cone tooth height and the circumferential groove height, which is 2 / 3 of the cone height h, that is, 2.5mm. The radial groove width is 2mm.

[0190] In step 3, the torque on a single friction surface can be calculated as follows:

[0191]

[0192] In the above formula, A ct is the total contact area of the multi-conical friction pair of trapezoidal bevel gears, A (i) is the contact area of a single cone surface, n is the number of contact surfaces of the multi-cone friction pair bevel gears, R (i) is the outer diameter of the i-th cone, r (i) is the inner diameter of the i-th cone.

[0193]

[0194] In the above formula, p ct is the actual contact pressure of the trapezoidal bevel gear multi-cone friction pair, F ct is the loading pressure of the multi-conical friction pair of trapezoidal bevel gear, then the friction torque M on a single friction surface of the trapezoidal bevel gear is ct(i) It can be expressed as:

[0195]

[0196] For a multi-conical friction pair, the total torque transmitted is the sum of the torques transferred by all friction surfaces. The total torque can be expressed as:

[0197]

[0198] In the above formula, Z c is the number of multi-cone friction pairs, based on the multi-cone friction pair structure, Z c = 2. k is the correction coefficient of friction torque of the friction pair, and k is taken as 0.75~0.85.

[0199] For a multi-conical friction pair, its axial dimension at separation can be expressed as:

[0200] L c =δ s1 +δ f +δ s2 +2δ h (1.11)

[0201] In the above formula, δ s1 and δ s2 are the thickness of the upper and lower multi-conical steel sheets respectively; δf is the thickness of the multi-conical friction plate; δ h is the separation gap of the multi-conical friction pair, take δ h Equal to the cone tooth height h.

[0202] The multi-conical friction pairs suitable for the design indicators obtained by comprehensive design are shown in Table 2:

[0203] Table 2

[0204]

[0205]

[0206] In step 4, the stress check steps for the multi-cone friction pair are as follows:

[0207] Stress check of bevel gear:

[0208] The normal stress of the bevel gear is numerically equal to the pressure on the contact surface, and its direction is consistent with the normal direction of the cone surface. The average normal stress of the trapezoidal and arc-shaped bevel gears can be obtained by combining formulas (1.4) and (1.5), respectively, and the maximum normal stress σ max The calculation method is:

[0209]

[0210] m=2.5·cos(α)(1.13)

[0211] In the above formula, m is the stress concentration factor. After calculation, m is 2.24, so σ max It is 25.28MPa, which is less than the allowable stress [σ].

[0212] The bevel teeth of the asymmetrically arranged friction pair have the same bevel height, bevel angle, and the same characteristics. The inner and outer diameters of the bevel teeth are 87.7mm and 88.1mm respectively. The calibration method is as follows:

[0213]

[0214] In the above formula, R0 is the inner diameter of the selected bevel tooth surface, R is the outer diameter of the selected bevel tooth surface, and S is the tooth top distance. After calculation, substitute the above formula into:

[0215]

[0216] Where Mc is the friction torque of the selected bevel tooth surface, which can be obtained by formula (1.9) or formula (1.6). The calculated shear stress value is 1.1 MPa, which is less than the allowable shear stress.

[0217] Stress check of friction plate:

[0218] The maximum shear stress will occur at F ct With F z At the midpoint radius of the action point, the shear stress verification formula is:

[0219]

[0220]

[0221] In the above formula, A is F ct With F z The cross-sectional area of the friction plate at the midpoint radius of the action point, p c is the pressure on the tooth surface of a single bevel gear, A (i) is the tooth surface area of a single bevel gear, and the calculated maximum shear stress is 1.44 MPa, which is less than the required shear stress.

[0222] In step 5, the method for checking the maximum temperature rise of the friction pair is:

[0223] The maximum temperature limit is set to 180°C. Based on the disc friction pair with the same inner and outer diameters as the multi-cone friction pair, the parameters of the clutch engagement process are imported into the disc friction pair temperature field calculation model. The friction pair engagement time is set to 0.6s, and the maximum temperature T of the disc friction pair is obtained. p 131.45℃, the maximum temperature T of the multi-cone friction pair is obtained using the empirical formula c :

[0224]

[0225] In the above formula, t is the friction pair engagement time, α is the bevel angle. The maximum temperature T c It is 151.7℃, which is lower than the maximum temperature of 180℃, meeting the working environment requirements. The design of the multi-conical friction pair is now completed.

[0226] In this embodiment, three bevel gear arrangements, namely symmetrical arrangement, asymmetrical arrangement and non-uniform arrangement, are proposed; two bevel gear types, namely trapezoidal bevel gear and arcuate bevel gear, are proposed; and applicable working conditions for each configuration are proposed.

[0227] A systematic design method for multi-conical friction pairs is proposed based on specific design indicators such as the inner and outer diameters of the friction pairs, the minimum transmission torque requirements of the friction pairs, and the axial separation size of the friction pairs, to carry out the taper tooth angle, taper tooth height, number of taper surfaces, and groove characteristics.

[0228] A torque calculation method for multi-cone friction pairs is proposed, and a torque correction coefficient is proposed.

[0229] A systematic method for stress verification of multi-cone friction pairs is proposed, and an empirical formula for the maximum temperature rise characteristics of multi-cone friction pairs is proposed, which helps to extend the life of multi-cone friction pairs.

[0230] This embodiment proposes a multi-cone clutch design method that includes parameter design and multi-physical field verification, so as to achieve the multi-cone clutch's ability to transmit large torque in a limited space, and utilizes stress verification and temperature verification to help improve the service life of the multi-cone friction pair.

[0231] The correlation between the configuration parameters such as the arrangement shape of multi-conical bevel gears, bevel gear height, bevel gear angle, groove characteristics and the stress and temperature rise characteristics of multi-conical friction pairs was analyzed, which comprehensively guided the design of multi-conical friction pairs.

[0232] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A design method for a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment, characterized in that: include: Determine the working environment characteristics and design indicators of the multi-cone clutch friction pair; Based on the working environment characteristics and specific design indicators, the multi-cone clutch friction pair is designed; wherein, the design of the multi-cone clutch friction pair includes: determining the arrangement form of the bevel teeth of the multi-cone clutch friction pair, determining the configuration parameters of the bevel teeth of the multi-cone clutch friction pair, and designing the groove characteristics of the multi-cone clutch friction pair; The designed multi-cone clutch friction pair is calibrated with preset parameters to complete the final design of the multi-cone clutch friction pair.

2. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 1 is characterized in that: The working environment characteristics of the multi-cone clutch friction pair include: high load and low speed working condition, medium-high load and medium-high speed working condition, and low load and high speed working condition; The design indicators of the multi-cone clutch friction pair include: inner diameter of the friction pair, outer diameter of the friction pair, minimum transmission torque of the friction pair, and separation axial dimension of the friction pair.

3. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 2 is characterized in that: Determining the arrangement of the bevel teeth of the friction pair of the multi-cone clutch includes: In high load and low speed working conditions, radially symmetrical bevel gear arrangement is adopted; In medium to high load and medium speed conditions, a radial asymmetric bevel gear arrangement is adopted; Under low load and high speed conditions, non-uniform bevel gear arrangement is adopted.

4. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 3 is characterized in that: Determining the configuration parameters of the bevel teeth of the friction pair of the multi-cone clutch includes: Determine the cone tooth type, cone tooth angle, cone tooth height, and number of cone surfaces of the multi-cone clutch friction pair.

5. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 4 is characterized in that: Determining the bevel gear type includes: The bevel gear types are divided into two types: trapezoidal bevel gears and arcuate bevel gears. The trapezoidal bevel gears are used in clutches with stable loads and long-term continuous operation, while the arcuate bevel gears are used in clutches with short-term impact loads and high peak torque requirements. The trapezoidal bevel gear is determined based on the bevel gear angle, cone height, and cone top distance; the arc-shaped bevel gear is determined based on the bevel gear radius, cone height, cone top distance, and arc radial difference; The bevel gear angle is designed based on a preset empirical threshold; The height of the bevel gear is: Among them, h c is the circumferential groove depth, h z is the thickness of the dual steel sheet, H cspr It is the axial dimension of the friction pair separation; For the multi-cone clutch friction pair with radially symmetrical bevel gear arrangement and radially asymmetrical bevel gear arrangement, the number of cone surfaces is: Among them, the inner diameter R of the friction pair i , outer diameter R of friction pair o , c is an empirical parameter; For the friction pair of a multi-cone clutch with non-uniform bevel gear arrangement, the number of cone surfaces is:

6. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 3 is characterized in that: Design of multi-cone clutch friction pair groove features includes: Two types of oil grooves are provided: circumferential grooves and radial grooves, both of which have rectangular cross-sections; The circumferential groove is arranged on the tooth top surface of the multi-cone bevel gear. The groove width is the same as the distance from the cone top, and the groove depth is the preset cone height value. The radial groove is a through groove that passes through the inner and outer diameters. The number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement, radially asymmetrical bevel gear arrangement, and non-uniform bevel gear arrangement is different; and the number of friction pairs arranged for multi-cone clutches with radially symmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement, and the number of friction pairs arranged for multi-cone clutches with radially asymmetrical bevel gear arrangement is greater than the number of friction pairs arranged for multi-cone clutches with non-uniform bevel gear arrangement; the depth of the radial groove has the ability to connect the oil chambers of each circumferential groove, and the radial groove depth should be the sum of the bevel gear height and the circumferential groove height.

7. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 1, characterized in that: The preset parameter verification of the designed multi-cone clutch friction pair includes: Check the torque parameters of the multi-cone clutch friction pair; Check the stress parameters of the multi-cone clutch friction pair; The maximum temperature of the multi-cone clutch friction pair is checked.

8. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 7, characterized in that: The torque parameter calibration of the multi-cone clutch friction pair includes: Calculate the maximum friction torque transmitted by each bevel gear; Calculate the sum of the maximum friction torque of all bevel gears; The maximum friction torque sum is compared with the design index of the multi-cone clutch friction pair to determine whether it meets the index.

9. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 7, characterized in that: The stress parameter verification of the multi-cone clutch friction pair includes: Check the stress of the bevel gear part; the bevel gear part includes: normal stress generated by extrusion and torsional shear stress generated by friction torque; Check the stress of the friction pair.

10. The design method of a multi-cone clutch friction pair for high-speed, heavy-load, unmanned equipment according to claim 7, characterized in that: The maximum temperature check of the multi-cone clutch friction pair includes: Based on a disc friction pair with the same inner and outer diameters as the multi-cone friction pair, the clutch engagement process parameters are introduced into the disc friction pair temperature field calculation model to obtain the maximum temperature of the disc friction pair. The maximum temperature of the multi-cone friction pair is obtained using an empirical formula. Compare the maximum temperature of the multi-cone friction pair with the maximum temperature limit to determine whether it meets the working condition requirements.

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