A short type universal coupling with adjustable length

Abstract

The application discloses a short type universal coupling with adjustable length and belongs to the technical field of couplings. The short type universal coupling comprises at least one joint component composed of a cross packing assembly and two flange fork heads connected with each other, the joint component can be connected with a driving end power output device and a driven end power receiving device; the driven end power receiving device is further connected with a driven end spline matching component, the driven end spline matching component comprises a driven end spline shaft sleeve and a driven end spline shaft; the driven end spline shaft sleeve is engaged with the driven end spline shaft through interference. When the driven end spline matching is contracted to the shortest, the length of the whole universal coupling reaches the shortest length, and the universal coupling is suitable for a small space installation position; when the driven end spline matching is stretched to the longest, the length of the whole universal coupling reaches the longest length. The universal coupling meets the demand of realizing power transmission within a certain range through an axial movement mode in a limited narrow space, and can effectively improve installation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of coupling technology, and more specifically, relates to a short universal coupling with adjustable length, which is suitable for equipment installation with small shaft spacing and also has axial adjustment function, thus having a wider range of applications. Background Technology

[0002] In steel rolling production, power transmission is typically achieved through couplings, and the universal joint is one of the most common types. Currently, universal joints are classified into two main categories based on whether they have a telescopic function: telescopic and non-telescopic.

[0003] 1) The standard telescopic cross-shaft universal coupling specified in JB / T5513, such as... Figure 1 As shown, the coupling includes a driving end joint I, a driven end joint II, and a spline assembly III. Spline assembly III connects driving end joint I and driven end joint II. In addition, couplings typically supplied by manufacturers also include two end bushings connected to the receiving shaft. The receiving shaft is connected to the motor or reducer via the driving end bushing, and the driven end bushing is connected to the roll end, as shown below. Figure 2 As shown.

[0004] Furthermore, Chinese patents CN104315007A, CN204267550U, CN211059233U, and CN203500314U also disclose similar structures. However, telescopic universal joints adjust the overall length of the coupling by adjusting the telescopic position of the spline in the middle to appropriately increase or decrease the length of the coupling to match the distance between the two shaft ends. However, when the installation space for shaft connection at the customer's site is limited, the adjustment structure of the aforementioned universal joint has limitations.

[0005] 2) In the standard structure of the cross-shaft universal coupling, the short, non-extensible structure, connected only by flange fork fasteners at both ends, can meet the installation requirements of the coupling within the limited space at the customer's site, such as... Figure 3 As shown. However, because the axial length of this structure is fixed, it is only suitable for on-site installation with fixed frames at both ends. Its installation and adjustment time is long, its efficiency is low, its applicability is limited, and it cannot meet the needs of customers. Summary of the Invention

[0006] 1. The problem to be solved

[0007] To address the problem of low installation efficiency of universal couplings in confined spaces in existing technologies, this invention provides a short universal coupling with adjustable length, which can meet the power transmission needs within a certain range through axial movement in a limited space, effectively improving installation efficiency.

[0008] 2. Technical Solution

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of the present invention provides a short universal coupling with adjustable length, comprising at least one joint component consisting of a cross-shaped assembly and two flange forks connected to each other, the joint component being capable of connecting a power output device at the active end and a power receiving device at the driven end;

[0011] It also includes a driven-end spline fit component connected to the driven-end power receiving device. The driven-end spline fit component includes a driven-end spline bushing and a driven-end spline shaft. The driven-end spline bushing engages with the driven-end spline shaft via interference fit. When the driven-end spline fit is contracted to its shortest length, the entire universal coupling reaches its shortest length, suitable for installation in smaller spaces. When the driven-end spline fit is extended to its longest length, the entire universal coupling reaches its longest length. This satisfies the need for power transmission within a certain range through axial movement in a limited and confined space, while also effectively improving installation efficiency.

[0012] Furthermore, the spline pair of the present invention is located at the end of the shaft, which makes it easy to regularly add lubricant to the lubricated spline pair, even in a confined space, and is easier to maintain.

[0013] The outer diameter D (mm) of the driven end spline bushing at the wall thickness section and the inner diameter d (mm) at the wall thickness section satisfy the following formula:

[0014]

[0015] get:

[0016] In the formula: T c —Calculate the torque, kN·m;

[0017] W t —Torsion section modulus;

[0018] τ—Shear stress at wall thickness, MPa;

[0019] [τ]—Allowable shear stress of the material, MPa.

[0020] In any embodiment of the first aspect of the present invention, the driven spline is an involute spline or a rectangular spline.

[0021] According to any embodiment of the first aspect of the present invention, the driven end spline is an involute spline, and the tooth surface strength σ p Satisfy the following formula:

[0022]

[0023] In the formula:

[0024] T – Transmitted torque, Nm;

[0025] z — the number of teeth in the spline;

[0026] l — Working (fitting) length of the spline teeth, mm;

[0027] d m —The average circle diameter, in mm, is equal to the pitch circle diameter, i.e., d. m =D0;

[0028] D0—Pitch circle diameter, mm, D0 = mz;

[0029] h——Key tooth working height, mm, involute spline h=m (α=30°) (m is the module);

[0030] ψ—Coefficient of uneven load between teeth, generally taken as ψ = 0.7 to 0.8, with a smaller value when there are many teeth (a large number of teeth when Z ≥ 44 teeth);

[0031] σ pp — Allowable compressive stress of spline, MPa.

[0032] Furthermore, in many conventional splined shafts and mating gears, very high stresses are observed at the spline ends during torsional loads. Therefore, to reduce such stresses, splined shafts primarily employ the following conventional methods to improve their performance: 1) increasing the shaft diameter, 2) increasing the surface hardness of the spline, and 3) selecting high-strength materials. However, increasing surface hardness requires sacrificing the ductility of the bushing material, which makes fatigue failure more likely during the service life of the splined shaft. In this invention, the driven end spline bushing engagement portion has a length l, and the spline width decreases at a certain angle from the shaft connection end to the engagement end (view from the driven end to the driving end), thus forming a taper A1. The stress reduction value Y1 obtained by the driven end spline bushing from the shaft connection end to the engagement end satisfies the following formula: Y1% = -801122*(A1 / l) 2 +7956.8*(A1 / l)-0.2*(d / D) represents only the numerical value and does not consider unit conversion.

[0033] According to any embodiment of the first aspect of the present invention, the driven end spline shaft is a solid shaft or a hollow shaft.

[0034] According to any embodiment of the first aspect of the present invention, the driven end spline shaft has an inner keyway in its inner bore, which engages with an external power receiving device via a key.

[0035] According to any embodiment of the first aspect of the invention, two articulated components are included, the flange forks of the two articulated components being connected and fixed by fasteners.

[0036] According to any embodiment of the first aspect of the present invention, a drive-end spline mating component is further included, comprising a drive-end spline bushing and a drive-end spline shaft, wherein the drive-end spline bushing is interference-engaged with the drive-end spline shaft.

[0037] The spline engagement portion has a length L, and the width of the spline decreases at a certain angle from the shaft end to the engagement end, thereby forming a taper A2. The stress reduction value Y2 obtained by the active end spline engagement component satisfies the following formula: Y2%=-801122*(A2 / L) 2 +7956.8*(A2 / L)-0.2*(d / D).

[0038] In any embodiment of the first aspect of the present invention, the active end spline is an involute spline or a rectangular spline.

[0039] According to any embodiment of the first aspect of the present invention, the active end spline shaft is a solid shaft or a hollow shaft.

[0040] According to any embodiment of the first aspect of the present invention, the inner hole of the active end shaft is provided with an inner keyway, which is engaged with an external power output device via a key.

[0041] 3. Beneficial effects

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) The adjustable-length short universal coupling of the present invention has the following characteristics: when the driven end spline fit is contracted to the shortest length, the length of the entire universal coupling reaches the shortest length, which is suitable for installation positions in small spaces; when the driven end spline fit is extended to the longest length, the length of the entire universal coupling reaches the longest length; it meets the need to achieve power transmission within a certain range through axial movement in a limited and narrow space, and can effectively improve installation efficiency.

[0044] (2) The adjustable-length short universal coupling of the present invention avoids the defects of uneven wall thickness when using thin-walled parts such as intermediate pipes to connect. The present invention is connected by joint components and the two ends adopt spline pair matching form, so the coupling has good stability in the process of transmitting torque.

[0045] (3) The adjustable-length short universal coupling of the present invention requires regular lubrication of its splined joint. The lubrication splined pair in the narrow space is located at the end of the shaft, which makes it easier to maintain. Attached Figure Description

[0046] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0047] Figure 1 It is a telescopic welded universal coupling according to existing technical standards;

[0048] Figure 2 The existing technical standard is for a telescopic welded universal coupling (including bushings);

[0049] Figure 3 This is a non-telescopic short universal coupling, which is currently in use.

[0050] Figure 4 This is a schematic diagram of the front view section of the adjustable-length short universal coupling of Embodiment 1 of the present invention;

[0051] Figure 5 for Figure 4 X-direction view;

[0052] Figure 6 for Figure 4 Y-direction view;

[0053] Figure 7 This is a front view sectional view of the driven end spline mating component of Embodiment 1 of the present invention;

[0054] Figure 8 This is the calculation process for selecting the driven end spline in Embodiment 1 of the present invention;

[0055] Figure 9 This is the calculation process of the spline on the driven end in Embodiment 1 of the present invention;

[0056] Figure 10 This is a front view sectional view of the adjustable-length short universal coupling of Embodiment 2 of the present invention;

[0057] Figure 11 This is a front view sectional view of the adjustable-length short universal coupling of Embodiment 3 of the present invention;

[0058] Figure 12 This is a schematic diagram of the front view section of the adjustable-length short universal coupling of Embodiment 4 of the present invention;

[0059] Figure 13 This is a front view sectional view of the driven end spline mating component of Embodiment 4 of the present invention;

[0060] Explanation of reference numerals in the attached figures:

[0061] 100. Cross-shaped pack assembly;

[0062] 200. Flange fork head; 210. End sleeve;

[0063] 300. Driven end spline mating component; 310. Driven end spline bushing; 320. Driven end spline shaft; 321. Inner keyway A;

[0064] 400. Spline mating component at the drive end; 410. Spline bushing at the drive end; 420. Spline shaft at the drive end; 421. Inner keyway B. Detailed Implementation

[0065] The following detailed description of exemplary embodiments of the invention is taken with reference to the accompanying drawings, which form part of the description and illustrate exemplary embodiments in which the invention may be practiced. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from the spirit and scope thereof. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and not restrictive of the description of the features and characteristics of the invention, to suggest the best mode for carrying out the invention, and is sufficient to enable those skilled in the art to practice the invention. Therefore, the scope of the invention is defined only by the appended claims.

[0066] The following detailed description and exemplary embodiments of the invention can be better understood in conjunction with the accompanying drawings, wherein the elements and features of the invention are identified by reference numerals.

[0067] Example 1

[0068] As is well known, a spline is a ridge or tooth on a drive shaft that meshes with a mating gear to transmit torque, while maintaining the angular relationship between the splined shaft and the mating gear, allowing them to rotate together in a 1:1 ratio. Generally, splined shafts are used in couplings that transmit large torques without slippage; to transmit power to floating or permanently fixed gears, pulleys, and other rotating components; and in coupling components that require frequent disassembly for indexing or changing angular positions.

[0069] like Figures 4 to 7As shown, the adjustable-length short universal coupling of this embodiment includes: two joint components consisting of a cross-shaped assembly 100 and two connected flange forks 200, and a driven-end spline-fit component 300 connected to a driven-end power receiving device (e.g., a rolling mill roll). The joint components can connect the driving-end power output device (e.g., a motor or reducer in the rolling mill) and the driven-end power receiving device via end sleeves 210. The driven-end spline-fit component 300 includes a driven-end spline bushing 310 and a driven-end spline shaft 320; the driven-end spline bushing 310 is interference-fitted with the driven-end spline shaft 320.

[0070]

Analysis of Working Boundary Conditions for the Driven Spline Bushing

[0071] 1. Driven end spline bushing wall thickness design

[0072] When designing the driven end spline bushing, the wall thickness should be as thin as possible while ensuring strength. The wall thickness is calculated according to formula (1):

[0073]

[0074] In formula (1):

[0075] T c —Calculate the torque, kN·m;

[0076] W t —The torsional section modulus is calculated according to formula (2);

[0077] τ—Shear stress at thin walls, [τ]—Allowable shear stress of the material, MPa; Allowable shear stress of commonly used materials is shown in Table 1;

[0078]

[0079] In formula (2):

[0080] D—Outer diameter at wall thickness, mm;

[0081] d—Inner diameter at the wall thickness point, mm;

[0082] Table 1 Allowable Shear Stress of Commonly Used Materials

[0083] Material grade Allowable shear stress [τ] 45 155 40Cr 200 42CrMo 240 38CrMoAl 280

[0084] Based on the selection of commonly used materials, such as 42CrMo, the inner diameter d at the wall thickness can be calculated as follows:

[0085] Right now

[0086] like Figure 7As shown, this embodiment uses a flange-type driven end spline bushing: the outer diameter of the bushing toothed portion is D2 (D2 equals the outer diameter D at the wall thickness), leaving space for the flange connection bolts, satisfying the following:

[0087] D2≤D4-D5-20················(4)

[0088] In equation (4):

[0089] D4—Bolt hole spacing, mm;

[0090] D5—Diameter of bolt through hole, mm;

[0091] Substituting D2 into formula (3), the maximum value of the bushing inner diameter D3 (D3 equals the inner diameter d at the wall thickness) is calculated.

[0092] It should be noted that the driven end spline bushing of this invention calculates the maximum value of the inner diameter d at the wall thickness. When the bushing's d is constant, the thinnest thickness of the bushing can be calculated. The thin-walled bushing effectively reduces weight, resulting in a lighter weight and lower moment of inertia. Furthermore, a smaller inner diameter d allows for a larger tooth diameter on the mating spline shaft, ensuring tooth strength and allowing for a wider range of choices in the number of teeth and module design. However, the inner diameter d of the bushing cannot be too small and must meet minimum safe operating conditions.

[0093] In this embodiment, the driven spline is an involute spline or a rectangular spline. For example... Figure 8 As shown, preferably, the driven end spline is an involute spline, and the tooth surface strength σ p Satisfy the following formula:

[0094]

[0095] In the formula:

[0096] T – Transmitted torque, Nm;

[0097] z — the number of teeth in the spline;

[0098] l — Working (fitting) length of the spline teeth, mm;

[0099] d m —The average circle diameter, in mm, is equal to the pitch circle diameter, i.e., d. m =D0;

[0100] D0—Pitch circle diameter, mm, D0 = mz;

[0101] h——Key tooth working height, mm, involute spline h=m (α=30°) (m is the module);

[0102] ψ—Coefficient of uneven load between teeth, generally taken as ψ = 0.7 to 0.8, with a smaller value when there are many teeth (a large number of teeth when Z ≥ 44 teeth);

[0103] σ pp — Allowable compressive stress of spline, MPa.

[0104] In addition, in many traditional splined shafts and mating gears, it has been observed that the spline ends are subjected to very high stress during torsional loads. Therefore, in order to reduce such stress, the following traditional methods are mainly used to improve the performance of splined shafts: 1) increase the shaft diameter, 2) increase the surface hardness of the spline, and 3) select high-strength materials.

[0105] However, to improve surface hardness, the ductility of the bushing material must be sacrificed, which makes the splined shaft more prone to fatigue failure during its service life. In an embodiment, the driven end splined bushing engagement portion has a length l, and the spline width decreases at a certain angle from the shaft connection end to the engagement end (view from the driven end to the driving end), thus forming a taper A1. When the driven end spline fit is contracted to its shortest length, the entire universal coupling reaches its shortest length, suitable for installation positions in smaller spaces. However, due to the short distance, spline stress tends to concentrate at the engagement end. Therefore, after extensive experiments and analysis, the stress reduction value Y1 obtained by the driven end splined bushing from the shaft connection end to the engagement end satisfies the following formula: Y1%=-801122*(A1 / l) 2 +7956.8*(A1 / l)-0.2*(d / D) represents only the numerical value and does not consider unit conversion.

[0106] In this invention, by calculating the maximum value of the inner diameter d at the wall thickness and substituting it into the above formula, the stress reduction value Y1 is also minimized. Under the conditions of use in confined spaces (e.g., low speed and high torque are required between the motor or reducer or the reducer and the roll in the rolling mill), the fit between the driven end spline bushing and the driven end spline shaft can be optimized, ensuring the safety of use.

[0107] Combination Figure 5 and Figure 6 As shown, the driven end splined shaft 320 is a solid shaft or a hollow shaft. The inner hole of the driven end splined shaft is provided with an inner keyway 321, which is keyed to the external power receiving equipment (rolls in the rolling mill).

[0108] 2. Selection of involute splines

[0109] The driven end spline bushing of the present invention cooperates with the driven end spline shaft to improve the load-bearing capacity of the involute spline in two main ways: 1) select a larger pitch circle diameter D and increase the length l of the spline teeth; 2) increase the pitch circle diameter D, increase the module m or increase the number of teeth z, while keeping the spline length l unchanged.

[0110] However, due to space limitations in this invention, the increase in the spline tooth length l (working length) of the short universal coupling is limited. In comparison, increasing the pitch circle diameter of the spline is more efficient. To avoid crushing (static connection) or excessive wear (dynamic connection) of the spline tooth working surface, the tooth surface strength should be calculated according to formula (5):

[0111]

[0112] In the formula:

[0113] T – Transmitted torque, Nm;

[0114] z — the number of teeth in the spline;

[0115] l — Working (fitting) length of the spline teeth, mm;

[0116] d m —The average circle diameter, in mm, is equal to the pitch circle diameter, i.e., d. m =D0;

[0117] D0—Pitch circle diameter, mm, D0 = mz;

[0118] h——Key tooth working height, mm, involute spline h=m (α=30°) (m is the module);

[0119] ψ—Coefficient of uneven load between teeth, generally taken as ψ = 0.7 to 0.8, with a smaller value when there are many teeth (a large number of teeth when Z ≥ 44 teeth);

[0120] σ pp — Allowable extrusion stress of spline, MPa, see Table 2;

[0121]

[0122] Combination Figure 8 , Figure 9 As shown, after designing the wall thickness of the driven end spline bushing as described above, and combining it with the calculation of spline extrusion stress, the optimal spline parameters can be designed.

[0123] Example 2

[0124] like Figure 10As shown, the structure of this embodiment is basically the same as that of Embodiment 1, except that: the adjustable-length short universal coupling of this embodiment includes a joint component consisting of a cross-shaped assembly 100 and two connected flange forks 200, and a driven-end spline fitting component 300 connected to a driven-end power receiving device (e.g., a roll in a rolling mill). The joint component can connect the driving-end power output device (e.g., a motor or reducer in a rolling mill) and the driven-end power receiving device. The driven-end spline fitting component 300 includes a driven-end spline bushing 310 and a driven-end spline shaft 320; the driven-end spline bushing 310 is interference-fitted with the driven-end spline shaft 320.

[0125] Example 3

[0126] like Figure 11 As shown, the structure of this embodiment is basically the same as that of embodiment 1, except that the adjustable length short universal coupling of this embodiment also includes a drive end spline mating component 400, which includes a drive end spline bushing 410 and a drive end spline shaft 420. The drive end spline bushing 410 is interference-fitted with the drive end spline shaft 420.

[0127] The structure of this embodiment is connected by joint components, and the two ends adopt a spline pair fit. The short universal coupling has good stability in the process of transmitting torque and avoids the defects of uneven wall thickness when using thin-walled parts such as intermediate pipes.

[0128]

Analysis of Working Boundary Conditions for the Active End Spline Bushing

[0129] 1. Design of the wall thickness of the active end spline bushing

[0130] When designing the active end spline bushing, the wall thickness should be as thin as possible while ensuring strength. The wall thickness is calculated according to formula (1):

[0131]

[0132] In formula (1):

[0133] T c —Calculate the torque, kN·m;

[0134] W t —The torsional section modulus is calculated according to formula (2);

[0135] τ—Shear stress at thin walls, [τ]—Allowable shear stress of the material, MPa; Allowable shear stress of commonly used materials is shown in Table 1;

[0136]

[0137] In formula (2):

[0138] D—Outer diameter at wall thickness, mm;

[0139] d—Inner diameter at the wall thickness point, mm;

[0140] Table 1 Allowable Shear Stress of Commonly Used Materials

[0141] Material grade Allowable shear stress [τ] 45 155 40Cr 200 42CrMo 240 38CrMoAl 280

[0142] Therefore, the inner diameter d at the wall thickness can be calculated:

[0143] Right now

[0144] The first type of flange-type active end spline bushing used in this embodiment: the outer diameter of the bushing tooth section is D2 (D2 equals the outer diameter D at the wall thickness), leaving space for the flange connection bolts, satisfying the following:

[0145] D2≤D4-D5-20··············(4)

[0146] In equation (4):

[0147] D4—Bolt hole spacing, mm;

[0148] D5—Diameter of bolt through hole, mm;

[0149] Substituting D2 into formula (3), the maximum value of the bushing inner diameter D3 (D3 equals the inner diameter d at the wall thickness) is calculated.

[0150] It should be noted that the maximum value of the inner diameter d at the wall thickness of the active end spline bushing of this invention is calculated. When the bushing's d is constant, the thinnest thickness of the bushing can be calculated. The thin-walled bushing can effectively reduce weight, resulting in a lighter weight and lower moment of inertia. In addition, a smaller inner diameter d of the bushing allows for a larger tooth diameter of the spline shaft it mates with, ensuring tooth strength and allowing for a wider range of choices in the design of the number of teeth and module. However, the inner diameter d of the bushing cannot be too small and must meet minimum safe operating conditions.

[0151] In this embodiment, the driving end spline is an involute spline or a rectangular spline. Preferably, the driving end spline is an involute spline, and the tooth surface strength σ p Satisfy the following formula:

[0152]

[0153] In the formula:

[0154] T – Transmitted torque, Nm;

[0155] z — the number of teeth in the spline;

[0156] l — Working (fitting) length of the spline teeth, mm;

[0157] dm —The average circle diameter, in mm, is equal to the pitch circle diameter, i.e., d. m =D0;

[0158] D0—Pitch circle diameter, mm, D0 = mz;

[0159] h——Key tooth working height, mm, involute spline h=m (α=30°) (m is the module);

[0160] ψ—Coefficient of uneven load between teeth, generally taken as ψ = 0.7 to 0.8, with a smaller value when there are many teeth (a large number of teeth when Z ≥ 44 teeth);

[0161] σ pp — Allowable compressive stress of spline, MPa.

[0162] Furthermore, the spline engagement portion has a length L, and the width of the spline decreases at a certain angle from the shaft end to the engagement end (view from the driving end to the driven end), thereby forming a taper A2. The stress reduction value Y2 obtained by the spline engagement component at the driving end satisfies the following formula: Y2%=-801122*(A2 / L) 2 +7956.8*(A2 / L)-0.2*(d / D).

[0163] Combination Figure 11 As shown, the active end spline shaft 420 is a solid shaft or a hollow shaft. The inner hole of the active end spline shaft 420 is provided with an inner keyway 421, which is keyed to the external power receiving equipment (rolls in the rolling mill).

[0164] 2. Selection of involute splines

[0165] In this embodiment, the active end spline bushing and the active end spline shaft cooperate to improve the load-bearing capacity of the involute spline in two main ways: 1) Select a larger pitch circle diameter D and increase the length l of the spline teeth; 2) Increase the pitch circle diameter D, increase the module m or increase the number of teeth z, while keeping the spline length l unchanged.

[0166] However, due to space limitations in this invention, the increase in the spline tooth length l (working length) of the short universal coupling is limited. In comparison, increasing the pitch circle diameter of the spline is more efficient. To avoid crushing (static connection) or excessive wear (dynamic connection) of the spline tooth working surface, the tooth surface strength should be calculated according to formula (5):

[0167]

[0168] In the formula:

[0169] T – Transmitted torque, Nm;

[0170] z — the number of teeth in the spline;

[0171] l — Working (fitting) length of the spline teeth, mm;

[0172] d m —The average circle diameter, in mm, is equal to the pitch circle diameter, i.e., d. m =D0;

[0173] D0—Pitch circle diameter, mm, D0 = mz;

[0174] h——Key tooth working height, mm, involute spline h=m (α=30°) (m is the module);

[0175] ψ—Coefficient of uneven load between teeth, generally taken as ψ = 0.7 to 0.8, with a smaller value when there are many teeth (a large number of teeth when Z ≥ 44 teeth);

[0176] σ pp — Allowable extrusion stress of spline, MPa, see Table 3;

[0177]

[0178] Example 4

[0179] like Figure 12 and Figure 13 As shown, the structure of this embodiment is basically the same as that of embodiment 1, except that: this embodiment uses a straight-shoulder driven end spline bushing 320, the outer diameter of the bushing tooth D2 (D2 is equal to the outer diameter D at the wall thickness) is equal to the rotation diameter D1 of the joint. After selecting a suitable material, substitute it into formula (3):

[0180]

[0181] Calculate the maximum value of the bushing inner diameter D3 (D3 equals the inner diameter d at the wall thickness).

[0182] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A short universal joint with adjustable length, comprising at least one joint component consisting of a cross-shaped assembly (100) and two connected flange forks (200), said joint component being capable of connecting a driving end power output device and a driven end power receiving device; characterized in that, It also includes a driven end spline fitting component (300) connected to the driven end power receiving device, the driven end spline fitting component (300) including a driven end spline bushing (310) and a driven end spline shaft (320); the driven end spline bushing (310) is interference-fitted with the driven end spline shaft (320); the outer diameter D at the wall thickness of the driven end spline bushing (310) and the inner diameter d at the wall thickness satisfy the following formula: ················（1） ·············（2） get: ··············（3） In the formula: T c —Calculate the torque, kN·m; W t —Torsion section modulus; τ—Shear stress at wall thickness, MPa; [τ]—Allowable shear stress of the material, MPa; The driven end splined bushing engagement portion has a length l Furthermore, the width of the spline decreases at a certain angle from the shaft connection end to the meshing end, forming a taper A1. The stress reduction value Y1 obtained by the driven end spline bushing from the shaft connection end to the meshing end satisfies the following formula: Y1% = -801122 * (A1 / l ) 2 + 7956.8 *(A1 / l ) - 0.2*(d / D).

2. The adjustable-length short universal coupling according to claim 1, characterized in that, The driven end spline is an involute spline or a rectangular spline.

3. The adjustable-length short universal coupling according to claim 2, characterized in that, The driven end spline is an involute spline, and the tooth surface strength is... Satisfy the following formula: ···············（4） In the formula: T—— Transmitted torque, Nm; z —— The number of teeth on a spline; l—— Working length of spline teeth, mm; —— The average circle diameter, in mm, is equal to the pitch circle diameter of the involute spline. ; —— Pitch circle diameter, mm ; h—— Key tooth working height, mm, involute spline h = m；α =30°; m Modulus; ψ—— The load unevenness coefficient between teeth is generally taken as... ψ =0.7~0.8, take the smaller value when there are many teeth: Z≥44 teeth is a large number of teeth; —— Allowable compressive stress of spline, MPa.

4. The adjustable-length short universal coupling according to claim 3, characterized in that, The driven end spline shaft (320) is a solid shaft or a hollow shaft.

5. The adjustable-length short universal coupling according to claim 4, characterized in that, The driven end spline shaft (320) has an inner keyway A (321) in its inner hole, which is connected to an external power receiving device via a key.

6. The adjustable-length short universal coupling according to claim 5, characterized in that, It includes two joint components, the flange forks (200) of which are connected and fixed by fasteners.

7. The adjustable-length short universal coupling according to any one of claims 1-6, characterized in that, It also includes a drive end spline mating component (400), which includes a drive end spline bushing (410) and a drive end spline shaft (420), wherein the drive end spline bushing (410) is interference-engaged with the drive end spline shaft (420).

8. The adjustable-length short universal joint according to claim 7, characterized in that, The active end spline is an involute spline or a rectangular spline.

9. The short universal joint with adjustable length according to claim 8, characterized in that, The active end spline shaft (420) is either a solid shaft or a hollow shaft.

10. The adjustable-length short universal joint according to claim 9, characterized in that, The inner hole of the active end spline shaft (420) is provided with an inner keyway B (421), which is connected to the external power output device by a key.

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