Cylindrical helical gear, power transmission device and vehicle

Abstract

The invention provides a cylindrical helical gear, a power transmission device and a vehicle, and relates to the technical field of transmission structures. The cylindrical helical gear comprises a gear body, and a plurality of gear teeth are arranged on the periphery of the gear body. Noise reduction grooves are formed in the tooth tops of the gear teeth. A first position and a second position which are sequentially arranged at an interval are arranged between the first end and the second end in the axial direction of the gear body, and the noise reduction groove is located between the first position and the second position; and when the cylindrical helical gears are meshed, the resultant force F1 of the periodic wave power generated from the first end to the first position is 0, and the resultant force F2 of the periodic wave power generated from the second position to the second end is 0. According to the cylindrical helical gear, the noise reduction groove is formed, so that the occurrence moment of the peak value of the periodic wave power is delayed, and the periodic wave power in the section between the first position and the second position can be partially counteracted during superposition, and therefore, the resultant force of the periodic wave power in the section between the first position and the second position can be reduced; and the vibration noise can be reduced.

Description

Technical Field

[0001] This application relates to the field of transmission structure technology, and in particular to a cylindrical helical gear, a power transmission device, and a vehicle. Background Technology

[0002] Helical gears are widely used in automotive and electrical engineering fields. Unlike spur gears, the meshing contact line of a helical gear gradually moves along its axial direction during meshing. This characteristic causes the equivalent meshing stiffness of the gear pair to change periodically as the meshing point passes through the tooth surface. Simultaneously, due to the helix angle, there is an inherent phase difference in the meshing state at different positions on the tooth width. Therefore, helical gears generate a periodic wave force with sinusoidal amplitude and direction that varies with time during meshing.

[0003] Periodic wave forces induce vibrations in gear systems and radiate noise, thus affecting the NVH (Noise, Vibration, and Harshness) performance of the product. Currently, the common technical means to reduce vibration and noise caused by periodic wave forces is to improve machining and assembly accuracy. However, improving machining and assembly accuracy has limited effect on reducing periodic wave forces, which is detrimental to improving the NVH performance of cylindrical helical gears. Summary of the Invention

[0004] This application provides a cylindrical helical gear, a power transmission device, and a vehicle to reduce the vibration and noise problems caused by periodic wave dynamics of the cylindrical helical gear.

[0005] In a first aspect, this application provides a cylindrical helical gear, comprising:

[0006] A gear body, the outer periphery of which has multiple teeth;

[0007] The tooth tip is provided with a noise reduction groove, which extends through both sides of the tooth along the circumference of the gear body;

[0008] Along the axial direction of the gear body, the gear teeth have a first end and a second end, and a first position and a second position are arranged sequentially at intervals between the first end and the second end, and the noise reduction groove is located between the first position and the second position;

[0009] The first position and the second position satisfy the following: when the cylindrical helical gears are meshing, the resultant force F1 of the periodic oscillation force generated in the first section from the first end to the first position is 0, and the resultant force F2 of the periodic oscillation force generated in the second section from the second position to the second end is 0.

[0010] In one possible implementation, the formula for calculating the resultant force F1 of the periodic undulating forces generated within the first section is:

[0011] ;

[0012] The formula for calculating the resultant force F2 of the periodic undulating forces generated in the second section is:

[0013] ;

[0014] Where ω is the angular frequency, t is time, β is the helix angle of the cylindrical helical gear, m is the module of the cylindrical helical gear, z is the position coordinate along the axial direction of the gear body, A is the amplitude, and π is pi. L is the axial distance between the first end and the first position on the gear body, and L is the axial distance between the first end and the second end on the gear body. The distance between the first end and the second position along the axial direction of the gear body.

[0015] In one possible implementation, the distance between the first position and the second position along the axial direction of the gear body is... satisfy: ;

[0016] Where π is the mathematical constant pi, m is the module of the cylindrical helical gear, and β is the helix angle of the gear body.

[0017] In one possible implementation, the width w of the noise reduction groove in the axial direction of the gear body satisfies: ,in, The distance between the first position and the second position along the axial direction of the gear body.

[0018] In one possible implementation, the depth h of the noise reduction groove satisfies: Where m is the module of the cylindrical helical gear.

[0019] In one possible implementation, a noise reduction groove is provided between the first position and the second position, and the noise reduction grooves on each of the gear teeth are located on the same circumference along the circumference of the gear body.

[0020] In one possible implementation, at least two noise reduction grooves are provided between the first position and the second position, and the corresponding noise reduction grooves on each gear tooth are located on the same circumference along the circumference of the gear body.

[0021] In one possible implementation, the noise reduction groove is any one of a rectangular groove, a trapezoidal groove, a triangular groove, or an arc-shaped groove.

[0022] Secondly, this application provides a power transmission device, including a device body and at least one pair of meshing gears, wherein at least one of the gears is a cylindrical helical gear as described in any of the above embodiments.

[0023] Thirdly, this application provides a vehicle, including a vehicle body and a power transmission device as described in the above embodiment, wherein the power transmission device is disposed on the vehicle body.

[0024] The cylindrical helical gear, power transmission device, and vehicle provided in this application achieve zero resultant force of periodic ripple forces generated in a first section from the first end to the first position and zero resultant force of periodic ripple forces generated in a second section from the second position to the second end during gear meshing. Furthermore, a noise-reducing groove is provided between the first and second positions to reduce the local meshing stiffness within the section between the first and second positions. When the meshing point of the gear teeth moves past the noise-reducing groove, the locally reduced meshing stiffness causes greater elastic deformation of the gear teeth, requiring the gear body to rotate at a larger angle. This delays the peak occurrence of the periodic ripple force, achieving phase delay. The phase delay allows the periodic ripple forces within the section between the first and second positions to partially cancel each other out during superposition, thereby reducing the resultant force of the periodic ripple forces within the section between the first and second positions, and consequently reducing vibration noise, thus improving the NVH performance of the cylindrical helical gear. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] Figure 1 This is a schematic diagram of the cylindrical helical gear in one of the embodiments of this application from one perspective;

[0027] Figure 2 for Figure 1 A schematic diagram of the cylindrical helical gear from another perspective;

[0028] Figure 3 for Figure 2 A schematic diagram of the structure of one of the gear teeth;

[0029] Figure 4 This is a comparison chart showing the verification of the original scheme without noise reduction slots and the optimized scheme with noise reduction slots.

[0030] Explanation of reference numerals in the attached figures:

[0031] 100 - Cylindrical helical gear; 110 - Gear body; 120 - Gear teeth; 130 - Noise reduction groove; 140 - First section; 150 - Second section;

[0032] 200 - First end; 300 - Second end; 400 - First position; 500 - Second position. The foregoing figures illustrate specific embodiments of this application, which will be described in more detail below. These figures and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] The terms "first," "second," "third," "fourth," etc., used in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0037] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or components is not necessarily limited to those steps or components that are explicitly listed, but may include other steps or components that are not explicitly listed or that are inherent to such process, method, product, or device.

[0038] When helical gears mesh, they generate a periodic wave dynamic force whose amplitude and direction vary sinusoidally over time. This periodic wave dynamic force can cause structural vibration and radiate noise, thus affecting the product's NVH performance.

[0039] Currently, the common technical approach to reduce vibration noise generated by periodic wave forces is to improve the machining and assembly accuracy of cylindrical helical gears. However, improving machining and assembly accuracy has limited effect on reducing periodic wave forces, thus hindering the improvement of NVH performance of cylindrical helical gears.

[0040] Based on this, embodiments of this application provide a cylindrical helical gear, a power transmission device, and a vehicle to reduce vibration noise caused by periodic wave dynamics, thereby improving NVH performance. The structure of the cylindrical helical gear is described below with reference to the accompanying drawings.

[0041] like Figure 1 and Figure 2 As shown, the cylindrical helical gear 100 of this application embodiment includes a gear body 110, and the outer periphery of the gear body 110 has a plurality of teeth 120. The tooth tip of the teeth 120 is provided with a noise reduction groove 130, and the noise reduction groove 130 extends through both sides of the teeth 120 in the circumferential direction of the gear body 110.

[0042] Along the axial direction of the gear body 110, the gear tooth 120 has a first end 200 and a second end 300, and a first position 400 and a second position 500 are arranged sequentially between the first end 200 and the second end 300. The noise reduction groove 130 is located between the first position 400 and the second position 500.

[0043] The first position 400 and the second position 500 satisfy the following: when the cylindrical helical gear 100 is engaged, the resultant force F1 of the periodic oscillating force generated in the first section 140 from the first end 200 to the first position 400 is 0, and the resultant force F2 of the periodic oscillating force generated in the second section 150 from the second position 500 to the second end 300 is 0.

[0044] The cylindrical helical gear 100 of this application divides the gear teeth 120 into three segments via a first position 400 and a second position 500 between the first end 200 and the second end 300. Since the resultant force of the periodic undulating forces generated in the first segment 140 from the first end 200 to the first position 400 is zero, and the resultant force of the periodic undulating forces generated in the second segment 150 from the second position 500 to the second end 300 is also zero, the periodic undulating forces in the first segment 140 and the second segment 150 do not generate vibration noise.

[0045] Furthermore, by setting a noise reduction groove 130 in the intermediate section between the first position 400 and the second position 500, the local meshing stiffness in the intermediate section is reduced. When the meshing point of the gear tooth 120 moves through the noise reduction groove 130, the locally reduced meshing stiffness causes the gear tooth 120 to produce greater elastic deformation. The gear body 110 needs to rotate a larger angle to achieve the same meshing force, which delays the peak time of the periodic ripple force, thereby delaying the phase of the periodic ripple force change curve.

[0046] The phase delay allows the periodic wave forces in the section between the first position 400 and the second position 500 to partially cancel each other out when superimposed, thereby reducing the resultant force of the periodic wave forces in the middle section between the first position 400 and the second position 500, which in turn helps to reduce vibration noise and improve the NVH performance of the cylindrical helical gear 100.

[0047] Each tooth 120 has a tooth tip surface and two opposing meshing surfaces. The tooth tip surface is located on the side of the tooth away from the gear body 110, and the two meshing surfaces are respectively located on two opposite sides of the tooth tip surface. The noise reduction groove 130 is recessed relative to the tooth tip surface and extends through the two meshing surfaces. Therefore, the opening of the noise reduction groove 130 is located on the tooth tip surface and the two meshing surfaces.

[0048] In one possible implementation, the formula for calculating the resultant force F1 of the periodic undulating forces generated within the first segment 140 is:

[0049] .

[0050] The formula for calculating the resultant force F2 of the periodic undulating forces generated within the second 150 section is:

[0051] .

[0052] Where ω is the angular frequency, t is time, β is the helix angle of the cylindrical helical gear 100, m is the module of the cylindrical helical gear 100, z is the position coordinate along the axial direction of the gear body 110, A is the amplitude, and π is pi. L is the axial distance between the first end 200 and the first position 400 on the gear body 110, and L is the axial distance between the first end 200 and the second end 300 on the gear body 110. The distance between the first end 200 and the second position 500 along the axial direction of the gear body 110 is denoted by A. Here, A represents the maximum amplitude of the wave force, i.e., the peak value of the amplitude. Amplitude A determines the upper limit of the intensity that the periodic wave force can reach throughout the entire oscillation period.

[0053] Specifically, for an ideal pair of cylindrical helical gears 100, the function expression for the position z of the periodic wave force along the axial direction of the gear body 110 is as follows:

[0054] .

[0055] Where ω is the angular frequency, t is time, β is the helix angle of the cylindrical helical gear 100, m is the module of the cylindrical helical gear 100, z is the position coordinate along the axial direction of the gear body 110, and A is the amplitude. Integrating the periodic wave force of the first segment 140 along the axial direction of the gear body 110, the resultant force F1 of the periodic wave force generated by the first segment 140 can be obtained by the following formula:

[0056] ;

[0057] get:

[0058] .

[0059] To make the resultant force F1 equal to 0, the following conditions must be met:

[0060] .

[0061] Simplifying, we obtain the distance between the first end 200 and the first position 400 along the axial direction of the gear body 110, which is also the ideal tooth width. The calculation formula is:

[0062] .

[0063] Where n1 is a natural number, π is pi, m is the module of the cylindrical helical gear 100, and β is the helix angle of the cylindrical helical gear 100. The unit of module is mm.

[0064] Integrating the periodic wave force of the second segment 150 along the axial direction of the gear body 110, the resultant force F2 of the periodic wave force generated by the second segment 150 can be obtained by the following formula:

[0065] ;

[0066] get:

[0067] .

[0068] To make the net force F2 equal to 0, the following conditions must be met:

[0069] ;

[0070] Simplifying, we obtain the distance between the second position 500 and the second end 300 along the axial direction of the gear body 110, which is also the ideal tooth width. The calculation formula is:

[0071] .

[0072] Among them, reference Figure 3 , Let n2 be the distance between the first end 200 and the second position 500 along the axial direction of the gear body 110, n2 be a natural number, π be pi, m be the module of the cylindrical helical gear 100, and β be the helix angle of the cylindrical helical gear 100. Following the order of n taking values ​​of 0, 1, 2, etc., the gears satisfying the above conditions will be... and The values ​​are arranged in ascending order, forming the ideal tooth width sequence: a1, a2, a3, etc. The unit for module here is mm.

[0073] Due to limitations such as external dimensions, the actual tooth width of the gear 120, that is, the distance between the first end 200 and the second end 300 in the axial direction of the gear body 110, generally does not meet the above-mentioned ideal tooth width conditions.

[0074] In this embodiment, by setting the first position 400 and the second position 500, the resultant force of the wave forces in the first segment 140 and the second segment 150 are both zero. Thus, the resultant force of the periodic wave forces of the entire cylindrical helical gear 100 is completely determined by the resultant force of the periodic wave forces in the intermediate segment between the first position 400 and the second position 500.

[0075] In one possible implementation, such as Figure 2 As shown, the noise reduction groove with a depth h of 130 satisfies: Where m is the module of the cylindrical helical gear 100. Here, the unit of module is mm. The determination of the depth h range of the noise reduction groove 130 is based on the following research findings and derivations: When no noise reduction groove 130 is formed at a certain position on the gear tooth 120 along the axial direction of the gear body 100, the periodic wave dynamic can be expressed as... Where ω is the angular frequency, t is the time, A is the amplitude, and φ is the initial phase at that position. Phase is a physical quantity that describes the state or position of a periodic fluctuation at a specific moment.

[0076] After creating a noise reduction groove 130 at the top of the gear tooth 120, the periodic wave dynamic function at that location is: .

[0077] Where h is the depth of the noise reduction slot 130. Therefore, the setting of the noise reduction slot 130 introduces a phase delay. To achieve mutual cancellation of periodic wave forces along the axial direction of the gear body 110, the phase difference between the periodic wave force after the noise reduction groove 130 is opened and the original periodic wave force without the noise reduction groove 130 needs to be between 2π / 3 and 4π / 3, that is, satisfy the following equation:

[0078] .

[0079] By solving this inequality, the design range of the depth h of the noise reduction groove 130 can be obtained: .

[0080] Specifically, the lower limit of the depth h of the noise reduction groove 130 is 2m / 9, which helps to avoid the problem of poor cancellation effect of the resultant force of periodic wave dynamics due to the depth h of the noise reduction groove 130 being too shallow. The upper limit of the depth h of the noise reduction groove 130 is 4m / 9, which helps to prevent performance instability caused by excessive delay, and also helps to prevent the depth h of the noise reduction groove 130 from being too deep, which would weaken the bending strength of the gear tooth 120.

[0081] In one possible implementation, the distance between the first position 400 and the second position 500 in the axial direction of the gear body 110 is... satisfy: Where π is the mathematical constant pi, m is the module of the cylindrical helical gear 100, and β is the helix angle of the cylindrical helical gear 100. The unit of module is mm.

[0082] Here, the distance between the intermediate segment between the first position 400 and the second position 500 is... Less than ,in, Based on the tooth width calculation formula The tooth width when n=1. This can be understood as the length corresponding to a complete cycle of the periodic wave dynamic in the axial direction of the gear body 110.

[0083] In this embodiment of the application, the width of the middle section is... The phase difference is limited to the length of a complete wave cycle. When the intermediate interval is less than a complete cycle, the phase difference of the wave forces at each point between the first position 400 and the second position 500 will not cover the full range from 0° to 360°, thus avoiding the complex situation where the cancellation effects cancel each other out due to complete phase. By setting the noise reduction slot 130, a dominant phase delay is introduced, providing a basis for achieving the cancellation of the resultant force of the periodic wave forces.

[0084] In addition, a narrower intermediate range means that the residual periodic wave dynamics resultant force that needs to be canceled is relatively small. After phase intervention through the noise reduction slot 130, the periodic wave dynamics can be canceled more easily, thereby weakening it to a lower level, thus creating conditions for reducing the periodic wave dynamics resultant force.

[0085] In one possible implementation, the width w of the noise reduction groove 130 in the axial direction of the gear body 110 in this embodiment of the application satisfies: .in, The distance between the first position 400 and the second position 500 in the axial direction of the gear body 110. Here, the setting of the width w range of the noise reduction groove 130 in the axial direction of the gear body 110 is conducive to ensuring that the noise reduction groove 130 generates sufficient phase modulation effect on the meshing point passing through its area.

[0086] Among them, making This ensures that the noise reduction groove 130 covers a sufficiently long portion of the middle section, rather than a narrow gap, thus ensuring that the noise reduction groove 130's intervention on the wave force is effective. Additionally, it makes... This ensures that the tooth tip area without the noise reduction groove 130 is still retained in the middle section. This allows the gear teeth 120 to have basic meshing and load-bearing capacity in the middle section, which helps to avoid the transmission function being weakened due to the excessive width w of the noise reduction groove 130, thus helping to achieve a balance between noise reduction and transmission reliability.

[0087] In one possible implementation, the noise reduction groove 130 is located in the middle between the first position 400 and the second position 500. This facilitates the determination of the position of the noise reduction groove 130, and also allows the phase delay effect generated by the noise reduction groove 130 to uniformly affect the wave dynamic distribution throughout the entire intermediate section, which helps to form destructive interference conditions in the intermediate section, thereby achieving a better resultant force cancellation effect and thus helping to reduce vibration noise.

[0088] Of course, it should be noted that the position of the noise reduction groove 130 is not limited to the middle of the first position 400 and the second position 500. In specific implementation, the position of the noise reduction groove 130 can still be adjusted according to the usage requirements.

[0089] In one possible implementation, such as Figure 1 and Figure 2 As shown, a noise reduction groove 130 is provided between the first position 400 and the second position 500. Along the circumference of the gear body 110, the noise reduction grooves 130 on each gear tooth 120 are located on the same circumference. Here, the noise reduction grooves 130 on each gear tooth 120 being located on the same circumference means that each noise reduction groove 130 is located on the same cross section in the radial direction of the gear body 110.

[0090] This configuration ensures that the stiffness reduction point and phase delay point of each tooth 120 are at exactly the same position. During rotation, the stiffness change experienced by each tooth during each meshing and the resulting wave force cancellation process of the cylindrical helical gear 100 are consistent and repeatable. This improves the smoothness of the entire operating cycle of the cylindrical helical gear 100, thereby achieving the technical effect of reducing vibration and noise.

[0091] Furthermore, locating the noise reduction grooves 130 on each gear tooth 120 on the same circumference facilitates the machining of the noise reduction grooves 130. In practice, using a standard groove machining tool (such as a forming lathe tool or grinding tool), the noise reduction grooves 130 on each gear tooth 120 can be machined by making one pass along the same circumference of the gear body 110. This not only improves the machining efficiency of the noise reduction grooves 130 but also enhances the machining accuracy.

[0092] In another possible implementation, at least two noise reduction grooves 130 are provided between the first position 400 and the second position 500. Along the circumference of the gear body 110, the corresponding noise reduction grooves 130 on each gear tooth 120 are located on the same circumference. Here, "the corresponding noise reduction grooves 130 on each gear tooth 120 are located on the same circumference" means that the number of noise reduction grooves 130 arranged along the axial direction of the gear body 110 determines the number of circumferential arrangements. "Multiple noise reduction grooves 130 located on the same circumference" means that each noise reduction groove 130 is located on the same radial section of the gear body 110.

[0093] For example, there are two noise reduction slots 130 arranged at intervals between the first position 400 and the second position 500. At this time, multiple noise reduction slots 130 located near the first position 400 are located on the same circumference. Multiple noise reduction slots 130 located near the second position 500 are located on the same circumference.

[0094] By setting at least two noise reduction grooves 130 between the first position 400 and the second position 500, the noise reduction grooves 130 can divide the middle section into at least three sub-segments, and phase intervention and wave dynamic cancellation can be performed in each sub-segment, thereby achieving a better noise reduction effect. In addition, similar to the scheme of setting a single noise reduction groove 130, multiple corresponding noise reduction grooves 130 are located on the same circumference, which also helps to improve the processing efficiency and processing accuracy of the noise reduction grooves 130.

[0095] In addition, in this embodiment, the noise reduction groove 130 is any one of a rectangular groove, a trapezoidal groove, a triangular groove, or an arc-shaped groove.

[0096] Specifically, along the circumference of the gear tooth body 110, the projection of the noise reduction groove 130 onto the meshing surface of the gear tooth 120 is rectangular, trapezoidal, triangular, or arc-shaped.

[0097] like Figure 2 and Figure 3 As shown, in a first possible embodiment, the noise reduction groove 130 is a rectangular groove. That is, the noise reduction groove 130 has two groove walls arranged opposite each other along the axial direction of the gear body 110, and a bottom wall connected between the bottom ends of the two groove walls. Both groove walls are perpendicular to the bottom wall, and the width of the noise reduction groove 130 is equal in the depth direction. The noise reduction groove 130 can also be a square groove (in which case the height of the groove wall is equal to the width of the groove bottom along the axial direction of the gear body 110), or it can be a rectangular groove (in which case the height of the groove wall and the width of the groove bottom along the axial direction of the gear body 110 are not equal).

[0098] Here, the projection of the noise reduction groove 130 onto the meshing surface of the gear tooth 120 is a rectangle with an open top. This makes the noise reduction groove 130 a rectangular groove, which is easy to obtain through standard machining methods such as turning and grinding, resulting in good machining consistency and easy machining shape.

[0099] In this embodiment, when the noise reduction groove 130 is a trapezoidal groove, it still has two groove walls and one bottom wall. Both groove walls are inclined relative to the bottom wall. The width of the noise reduction groove 130 gradually increases or decreases along the direction from the tooth tip to the bottom wall. In this case, the projected shape of the noise reduction groove 130 is a trapezoid with an open top, which also has the advantage of being easy to process and shape.

[0100] In the third embodiment, when the noise reduction groove 130 is a triangular groove, it has two groove walls arranged opposite each other along the axial direction of the gear body 110. The two groove walls are inclined and their bottom ends intersect. The width of the noise reduction groove 130 gradually decreases along the direction from the tooth tip to the bottom of the noise reduction groove 130. At this time, the projection of the noise reduction groove 130 on the meshing surface of the gear tooth 120 is a triangle with an open top, which also has the advantage of being easy to process and form.

[0101] In the fourth embodiment, the noise reduction groove 130 is an arc-shaped groove, and the entire groove wall of the noise reduction groove 130 is arc-shaped, such as a semi-circular arc groove.

[0102] It is understood that the shape of the noise reduction groove 130 is not limited to the shape described above. In specific implementation, the shape of the noise reduction groove 130 can be adjusted according to the usage requirements.

[0103] To verify the technical effect of the noise reduction groove 130 in the embodiments of this application, a pair of mating cylindrical helical gears 100 are used for comparison. The driving gear has 29 teeth, the driven gear has 81 teeth, the gear module m is 1.48 mm, the tooth width of the gear teeth 120 (the distance between the first end 200 and the second end 300 in the axial direction of the gear body 110) is 40 mm, and the helix angle β of the cylindrical helical gear 100 is 25.5°.

[0104] To meet the ideal tooth width conditions Where n is a natural number, when different n is selected, the tooth width l arranged in ascending order to form the ideal tooth width sequence are 0mm, 10.8mm, 21.6mm, 32.4mm, 43.2mm, 54mm, 64.8mm, etc.

[0105] Select the length of the first segment, 140, from the above ideal tooth width sequence. The length of the second section 150 This determines the first position 400 and the second position 500. For example, the length of the first segment 140. The length of the second section is 150 mm, which is 32.4 mm. It is 40mm (coinciding with the second end 300).

[0106] The noise reduction groove 130 is located at an intermediate position between the first position 400 and the second position 500. At this time, the axial distance l between the noise reduction groove 130 and the first end 200 on the gear body 110 satisfies: The value of l is 36.2 mm.

[0107] The width w of the noise reduction groove 130 can be set to half the axial distance between the first position 400 and the second position 500 on the gear body 110, that is, the width w of the noise reduction groove 130: That is, the width w is 3.8mm. The depth h of the noise reduction groove 130 is: h=m / 3, and the calculated depth h is 0.5mm.

[0108] Simulations verified the original scheme without noise reduction slot 130 and the optimized scheme with noise reduction slot 130. The simulation results are as follows. Figure 4 As shown. Figure 4 The horizontal axis represents time, measured in seconds (s), illustrating a time segment during the rotation of the cylindrical helical gear 100. The vertical axis represents the magnitude of the resultant force of the periodic wave dynamics, measured in kilometers (N).

[0109] from Figure 4It can be seen that the original scheme has a larger resultant force amplitude of periodic fluctuations and a larger difference between the peaks and troughs, resulting in greater fluctuations in the curve. The optimized scheme weakens the resultant force amplitude of periodic fluctuations and reduces the difference between the peaks and troughs, making the curve of the optimized scheme smoother.

[0110] Depend on Figure 4 As can be seen, in the optimized scheme with noise reduction groove 130, the resultant amplitude of the periodic oscillation force is reduced. Specifically, compared to the original scheme without noise reduction groove 130, the optimized scheme with noise reduction groove 130 reduces the amplitude of the periodic oscillation force. Specifically, at a speed of 600 rpm, the amplitude of the 29th-order oscillation force of the cylindrical helical gear 100 can be reduced from 3.1 N to 0.4 N. Therefore, by creating noise reduction groove 130 on the gear teeth 120, the vibration and noise problems of the cylindrical helical gear during meshing can be solved, thereby improving NVH performance.

[0111] In this embodiment of the circular helical gear, by providing noise reduction grooves 130 at the first position 400 and the second position 500, the resultant force F1 of the periodic undulating force in the first section 140 between the first end 200 and the first position 400 is 0, and the resultant force F2 of the periodic undulating force in the second section 150 between the second position 500 and the second end 300 is 0. This allows the periodic undulating force of the cylindrical helical gear 100 at the meshing position to be better canceled along the axial direction of the gear body 110, thereby reducing the magnitude of the resultant force of the periodic undulating force of the cylindrical helical gear 100 and thus reducing the vibration noise caused by the periodic undulating force of the cylindrical helical gear 100.

[0112] In addition, compared with the existing technology for improving the machining and assembly accuracy of the cylindrical helical gear 100, the solution of setting the noise reduction groove 130 has the advantages of simple structure and easy implementation while reducing the vibration noise caused by periodic wave dynamics.

[0113] This application also provides a power transmission device, including a device body and at least one pair of meshing gears, wherein at least one gear is a cylindrical helical gear 100 as described in any of the above embodiments.

[0114] The power transmission device can be a gearbox, reducer, etc., and the device body can be a housing, etc. The number of gears can be determined according to the usage requirements. This power transmission device uses at least one cylindrical helical gear as described above, which helps to reduce the vibration and noise of the power transmission device, thereby improving the NVH performance of the power transmission device.

[0115] This application also provides a vehicle, including a vehicle body and the power transmission device described above. The power transmission device is disposed on the vehicle body. For example, the power transmission device described above is included in a vehicle's gearbox or reducer.

[0116] The vehicle described in this application, by setting up the power transmission device as described above, helps to reduce vibration and noise generated in gear transmission, thereby improving the vehicle's NVH performance and comfort.

[0117] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0118] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A cylindrical helical gear, characterized in that, include: Gear body (110), the outer periphery of which has a plurality of teeth (120). The tooth tip of the gear (120) is provided with a noise reduction groove (130), and the noise reduction groove (130) extends through both sides of the gear (120) along the circumference of the gear body (110). Along the axial direction of the gear body (110), the gear teeth (120) have a first end (200) and a second end (300), and a first position (400) and a second position (500) are arranged sequentially at intervals between the first end (200) and the second end (300), and the noise reduction groove (130) is located between the first position (400) and the second position (500); The first position (400) and the second position (500) satisfy the following: when the cylindrical helical gear (100) is engaged, the resultant force F1 of the periodic undulating force generated in the first section (140) from the first end (200) to the first position (400) is 0, and the resultant force F2 of the periodic undulating force generated in the second section (150) from the second position (500) to the second end (300) is 0.

2. The cylindrical helical gear according to claim 1, characterized in that, The formula for calculating the resultant force F1 of the periodic undulating forces generated within the first section (140) is as follows: ； The formula for calculating the resultant force F2 of the periodic undulating forces generated within the second section (150) is as follows: ； Where ω is the angular frequency, t is time, β is the helix angle of the cylindrical helical gear (100), 200 is the module of the cylindrical helical gear (100), z is the position coordinate along the axial direction of the gear body (110), A is the amplitude, and π is pi. L is the axial distance between the first end (200) and the first position (400) on the gear body (110), and L is the axial distance between the first end (200) and the second position (500) on the gear body (110). The distance between the first end (200) and the second position (500) in the axial direction of the gear body (110).

3. The cylindrical helical gear according to claim 2, characterized in that, The distance between the first position (400) and the second position (500) in the axial direction of the gear body (110) satisfy: ; Wherein, π is pi, m is the module of the cylindrical helical gear (100), and β is the helix angle of the gear body (110).

4. The cylindrical helical gear according to claim 3, characterized in that, The width w of the noise reduction groove (130) in the axial direction of the gear body (110) satisfies: ,in, The distance between the first position (400) and the second position (500) in the axial direction of the gear body (110).

5. The cylindrical helical gear according to any one of claims 1 to 4, characterized in that, The depth h of the noise reduction groove (130) satisfies: Where m is the module of the cylindrical helical gear (100).

6. The cylindrical helical gear according to any one of claims 1 to 4, characterized in that, A noise reduction groove (130) is provided between the first position (400) and the second position (500), and the noise reduction grooves (130) on each of the gear teeth (120) are located on the same circumference along the circumference of the gear body (110).

7. The cylindrical helical gear according to any one of claims 1 to 4, characterized in that, There are at least two noise reduction grooves (130) between the first position (400) and the second position (500), and the noise reduction grooves (130) on each gear tooth (120) are located on the same circumference along the circumference of the gear body (110).

8. The cylindrical helical gear according to any one of claims 1 to 4, characterized in that, The noise reduction groove (130) is any one of a rectangular groove, a trapezoidal groove, a triangular groove or an arc groove.

9. A power transmission device, characterized in that, It includes a device body and at least one pair of meshing gears, at least one of the gears being a cylindrical helical gear (100) as claimed in any one of claims 1 to 8.

10. A vehicle, characterized in that, It includes a vehicle body and the power transmission device as described in claim 9, wherein the power transmission device is disposed on the vehicle body.

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