Gear shaft, gear transmission structure and gear box

Abstract

The utility model provides a gear shaft, a gear transmission structure and a gear box, and relates to the field of gear manufacturing. The gear shaft is used for being matched with an intermediate gear with an internal spline and comprises a shaft body, a gear body and an external spline. The gear body and the external spline are arranged in the axial direction of the shaft main body; the gear body is provided with an inclined tooth groove used for guiding oil. The outer spline comprises a plurality of outer tooth bodies, the outer tooth bodies are arranged around the axis of the shaft body at intervals, the ends, away from the shaft body, of the outer tooth bodies are provided with leading-in sections, and the outer spline is used for being inserted into the intermediate gear through the leading-in sections so that the outer spline can be meshed with the inner spline; the width of the leading-in section is gradually reduced in the direction from the tooth root of the outer tooth body to the tooth top of the outer tooth body, and the width of the leading-in section is gradually increased in the direction from the outer spline to the gear body. The guiding end face, away from the gear body, of the guiding-in section is an arc-shaped face. When the gear shaft and the intermediate gear are subjected to press fitting, the dependence on a positioning tool is small, the press fitting steps are simplified, the press fitting efficiency is improved, and the press fitting cost is reduced.

Description

Technical Field

[0001] The utility model relates to the field of gear manufacturing, in particular to a gear shaft, a gear transmission structure and a gear box. Background Art

[0002] In some reduction gearboxes, especially those for new energy vehicles, the gear shaft and the intermediate gear of the gearbox mostly use spline interference fit to transmit torque, where the spline on the gear shaft is an external spline and the spline on the intermediate gear is an internal spline. When assembling the gear shaft and the intermediate gear, the gear shaft needs to be pressed into the assembly inner hole of the intermediate gear. During the press-fitting process, it is necessary to ensure that the external spline and the internal spline are fully matched before pressing in, otherwise there will be a deviation in the pressing or the spline end will be crushed, resulting in iron filings.

[0003] In the existing technical solutions, in order to ensure the quality of press-fitting, different bevel angles are generally processed at the ends of the external splines or internal splines to reduce the contact area between the external splines and the internal splines during the alignment process before press-fitting and reduce the probability of interference. However, in actual application, the effect is still not ideal; therefore, in the actual press-fitting process, it is still necessary to use an additional pre-positioning gear alignment mechanism before press-fitting can be carried out, which increases the press-fitting operation steps, reduces assembly efficiency, and increases assembly costs. Utility Model Content

[0004] The utility model aims to provide a gear shaft, a gear transmission structure and a gear box, which can simplify the press-fitting operation steps, improve the assembly efficiency and reduce the assembly cost.

[0005] The embodiment of the utility model is achieved as follows:

[0006] In a first aspect, the utility model provides a gear shaft for cooperating with an intermediate gear having an internal spline, comprising:

[0007] A shaft body, a gear body and an external spline, wherein the gear body and the external spline are both formed on the outer peripheral surface of the shaft body, and the gear body and the external spline are arranged in the axial direction of the shaft body; the gear body is provided with an oblique tooth groove for guiding oil; the external spline comprises a plurality of external tooth bodies, and the plurality of external tooth bodies are arranged at intervals around the axis of the shaft body, and an introduction section is provided at one end of the external tooth body away from the shaft body, and the external spline is used to insert the intermediate gear through the introduction section so that the external spline is meshed with the internal spline;

[0008] The width of the introduction section gradually decreases in the direction from the root of the external tooth body to the top of the tooth of the external tooth body, and the width of the introduction section gradually increases in the direction from the external spline to the gear body; the guide end surface of the introduction section away from the gear body is set as an arc surface; wherein the width direction of the introduction section is consistent with the circumferential direction of the shaft body.

[0009] In an optional embodiment, the tooth top surface of the introduction section is configured as an arc-shaped surface.

[0010] Based on the above scheme, by setting the tooth top surface of the introduction section as an arc surface, during the process of press-fitting the gear shaft and the intermediate gear, the introduction section first enters the assembly inner hole of the intermediate gear, and the guide end surface of the introduction section first contacts the end of the internal spline of the intermediate gear. Under the guidance of the guide end surface, the gear shaft can adaptively rotate relative to the intermediate gear to achieve adaptive adjustment of the circumferential position, thereby reducing the probability of interference between the guide end surface and the end of the internal spline, which is conducive to the guide end surface entering the tooth groove of the internal spline. Then, as the introduction section continues to be inserted into the internal spline, the arc-shaped tooth top surface and the internal spline are in point contact, with a small contact area and small friction, and also has a guiding effect, so that the external spline and the internal spline are further aligned, and it is not easy to cause the spline end to be damaged due to bias. The press-fitting is convenient and reliable, and the matching quality of the internal spline and the external spline is high.

[0011] In an optional embodiment, the tooth top surface has an angle with the axis of the shaft body, and the distance between the tooth top surface and the axis of the shaft body gradually decreases in the direction from the gear body to the external spline, and the lowest position of the tooth top surface is not higher than the position of the tooth top circle of the external tooth body.

[0012] Based on the above scheme, since there is an angle between the tooth top surface and the axis of the shaft body, during the process of inserting the lead-in section into the internal spline, at first, the distance between the tooth top surface and the bottom wall of the tooth groove of the internal spline is large, and interference is not easy to occur. As the insertion depth of the lead-in section increases, the tooth top surface gradually contacts the bottom wall of the tooth groove of the internal spline, and guides the gear shaft to adaptively move in the radial direction relative to the intermediate gear, thereby compensating for the radial position offset and aligning the radial positions of the gear shaft and the intermediate gear, ensuring smooth press fitting and improving the press fitting quality.

[0013] In an optional embodiment, the angle between the tooth top surface and the axis of the shaft body is set between 15-30°.

[0014] Based on the above scheme, the inclination angle of the tooth top surface is in the range of 15-30°. Under the premise of ensuring that the lead-in section is easy to insert into the internal spline, it is convenient for both the processing of the tooth top surface and the design of the structural dimensions of the lead-in section. The length and height of the lead-in section are moderate to ensure that the tooth shape of the external spline meets the set requirements.

[0015] In an optional embodiment, the shaft body includes a first shaft segment, a second shaft segment and a third shaft segment connected in sequence, the outer diameter of the second shaft segment is larger than the outer diameters of the first shaft segment and the third shaft segment, the gear body is arranged on the outer circumferential surface of the first shaft segment, and the external spline is arranged on the outer circumferential surface of the second shaft segment; the guide end face protrudes from the end face of the second shaft segment connected to the third shaft segment.

[0016] Based on the above scheme, the guide end face is protruded from the end face of the second shaft segment. During the press-fitting process of the gear shaft and the intermediate gear, the third shaft segment gradually approaches the intermediate gear. The third shaft segment has a small outer diameter and a small coverage area, and the probability of collision with the intermediate gear is small. The third shaft segment can smoothly enter the assembly inner hole of the intermediate gear, playing a role in preliminary positioning. As the press-fitting action proceeds further, the guide end face of the lead-in segment first contacts the internal spline. Since the guide end face is convexly arranged on the end face of the second shaft segment, the guide end face can intervene in the guide earlier and the guide effect is better.

[0017] In an optional embodiment, the introduction section includes a first guide side surface and a second guide side surface, and the first guide side surface and the second guide side surface are arranged in the width direction of the introduction section, and the first guide side surface and the second guide side surface are both connected to the tooth top surface of the introduction section, and the first guide side surface, the second guide side surface and the tooth top surface converge on the side of the tooth top surface close to the gear body, and the width of the portion where the tooth top surface is connected to the first guide side surface and the second guide side surface gradually increases in the direction from the gear body to the external spline.

[0018] Based on the above solution, when the introduction section is inserted into the internal spline of the intermediate gear, both the first guide side surface and the second guide side surface can contact the internal spline to play a correction role, which is beneficial to the radial direction of the press-fitting action.

[0019] In a second aspect, the utility model provides a gear transmission structure, the gear transmission structure comprising:

[0020] The intermediate gear and the gear shaft according to any one of the aforementioned embodiments, wherein the intermediate gear is provided with an assembly inner hole, the hole wall of the assembly inner hole is provided with an internal spline, the gear shaft is inserted into the assembly inner hole, and the external spline on the gear shaft is meshed with the internal spline.

[0021] In an optional embodiment, the internal spline includes a plurality of internal tooth bodies arranged at intervals around the axis of the intermediate gear, and the plurality of external tooth bodies and the plurality of internal tooth bodies are alternately arranged in sequence in the circumferential direction of the intermediate gear; the external tooth body has two end portions in the axial direction of the intermediate gear, and at least one of the two end portions is provided with a chamfer.

[0022] Based on the above solution, since the external spline is provided with a guide section, combined with the chamfer on the internal spline, the probability of interference generated when the two are docked can be further reduced, thereby reducing the difficulty of press fitting, eliminating the need for additional positioning tooling, reducing the difficulty of press fitting, and reducing the cost of press fitting.

[0023] In an optional embodiment, the chamfer is configured as a rounded corner or a chamfered corner.

[0024] Based on the above solution, the chamfering can be set as needed, and the processing is flexible.

[0025] In a third aspect, the utility model provides a gear box, the gear box comprising:

[0026] The gear transmission structure according to any one of the preceding embodiments.

[0027] The beneficial effects of the embodiments of the utility model are:

[0028] In summary, the gear shaft provided in the present embodiment is provided with an introduction section at the end of the external tooth body of the external spline for plugging with the internal spline, the width of the introduction section gradually decreases in the direction from the tooth root of the external tooth body to the tooth top of the external tooth body, and the width of the introduction section gradually increases in the direction from the external spline to the gear body, and the guide end face of the introduction section away from the gear body is provided as an arc surface, so that when the gear shaft and the intermediate gear are press-fitted, the end of the gear shaft with the introduction section is aligned with the intermediate gear, and in the process of the gear shaft and the intermediate gear approaching each other, the introduction section first contacts with the internal spline on the intermediate gear, and the guide end face of the introduction section is an arc surface, and the contact with the internal spline is a point contact, with a small contact area and small friction force, and under the action of obstruction, when the press-fitting force is applied to make the two continue to approach, under the guidance of the guide end face, the gear shaft can adaptively rotate relative to the intermediate gear, so that the internal spline is aligned with the external spline, so that the internal spline and the external spline can be smoothly clamped together, and it is not easy to have bias pressure, and it is not easy to damage the internal spline and the external spline, thereby improving the safety of press-fitting. At the same time, the additional positioning and alignment tooling is eliminated, which reduces the difficulty of operation and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of a gear shaft according to an embodiment of the present utility model;

[0031] Figure 2It is a schematic isometric view of a gear shaft according to an embodiment of the utility model;

[0032] Figure 3 for Figure 1 Schematic cross-sectional view along the AA direction;

[0033] Figure 4 for Figure 1 A cross-sectional schematic diagram along the BB direction;

[0034] Figure 5 for Figure 1 Schematic cross-sectional view along CC direction;

[0035] Figure 6 A schematic diagram of an intermediate gear according to an embodiment of the present utility model;

[0036] Figure 7 Schematic diagram of the gear transmission structure of an embodiment of the present utility model.

[0037] icon:

[0038] 001-gear shaft; 100-shaft body; 101-first shaft section; 102-second shaft section; 103-third shaft section; 120-gear body; 121-external teeth; 122-oblique tooth grooves; 140-external splines; 141-external tooth body; 142-introduction section; 143-guide end face; 144-tooth top face; 145-first guide side face; 146-second guide side face; 002-intermediate gear; 200-internal splines; 201-chamfer. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0042] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0043] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0044] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] In the prior art, when assembling the gear shaft 001 and the intermediate gear 002, it is necessary to align and mesh the external spline 140 on the gear shaft 001 with the internal spline 200 on the intermediate gear 002. It is difficult to align the two structures by themselves, and bias pressure is likely to occur during the press-fitting process, resulting in damage to the internal spline 200 and the external spline 140. Therefore, it is generally necessary to configure a special press-fitting positioning tool to adjust the position of the internal spline 200 and the external spline 140. This is cumbersome, inefficient, and costly.

[0046] In view of this, the designer provides a gear shaft 001 that can adaptively adjust its position during the press-fitting process so as to align with the intermediate gear 002, reduce dependence on additional positioning tooling, simplify the press-fitting steps, improve press-fitting efficiency, and reduce press-fitting costs.

[0047] Please combine Figure 1-Figure 5In this embodiment, the gear shaft 001 is used to cooperate with the intermediate gear 002 having the internal spline 200, and the gear shaft 001 includes a shaft body 100, a gear body 120 and an external spline 140. The gear body 120 and the external spline 140 are both formed on the outer peripheral surface of the shaft body 100, and the gear body 120 and the external spline 140 are arranged in the axial direction of the shaft body 100; the gear body 120 is provided with an oblique tooth groove 122 for guiding oil; the external spline 140 includes a plurality of external tooth bodies 141, and the plurality of external tooth bodies 141 are arranged at intervals around the axis of the shaft body 100, and an introduction section 142 is provided at one end of the external tooth body 141 away from the shaft body 100, and the external spline 140 is used to pass through the introduction section 142 is inserted into the intermediate gear 002 so that the external spline 140 is meshed with the internal spline 200; the width of the introduction section 142 gradually decreases in the direction from the root of the external tooth body 141 to the top of the tooth of the external tooth body 141, and the width of the introduction section 142 gradually increases in the direction from the external spline 140 to the gear body 120; the guide end face 143 of the introduction section 142 away from the gear body 120 is set as an arc surface; wherein, the width direction of the introduction section 142 is consistent with the circumference of the shaft body 100.

[0048] Based on the above solution, the press-fitting method of the gear shaft 001 and the intermediate gear 002 provided in this embodiment includes, for example:

[0049] Please combine Figure 1 , Figure 2 , Figure 6 and Figure 7 When the gear shaft 001 and the intermediate gear 002 are press-fitted, one end of the gear shaft 001 with the introduction section 142 is aligned with the intermediate gear 002. When the gear shaft 001 and the intermediate gear 002 are approaching each other, the introduction section 142 first contacts the internal spline 200 on the intermediate gear 002. The guide end face 143 of the introduction section 142 is an arc surface, and the contact with the internal spline 200 is a point contact, with a small contact area and small friction. Under the action of resistance, when the press-fitting force is applied to make the two continue to approach, under the guidance of the guide end face 143, the gear shaft 001 can adaptively rotate relative to the intermediate gear 002, so that the internal spline 200 is aligned with the external spline 140, so that the internal spline 200 and the external spline 140 can be smoothly clamped together, and it is not easy to have bias pressure, and it is not easy to damage the internal spline 200 and the external spline 140, thereby improving the safety of press-fitting. At the same time, the additional positioning and alignment tooling is omitted, the difficulty of operation is reduced, and the cost is saved.

[0050] The following embodiments illustrate the details of the gear shaft 001 provided in the present application by way of examples.

[0051] In this embodiment, optionally, the gear shaft 001 includes an integrated shaft body 100, a gear body 120 and an external spline 140. The gear body 120 and the external spline 140 are both arranged on the outer circumferential surface of the shaft body 100. The shaft body 100, the gear body 120 and the external spline 140 are integrally formed, with few seams, high overall structural strength, not easily damaged during use, and long service life.

[0052] Please combine Figure 3 Optionally, the shaft body 100 is set to a stepped shaft structure, and the shaft body 100 includes a first shaft section 101, a second shaft section 102 and a third shaft section 103 connected in sequence, and the first shaft section 101, the second shaft section 102 and the third shaft section 103 are all cylindrical sections, and the outer diameter of the first shaft section 101 and the outer diameter of the third shaft section 103 are both smaller than the outer diameter of the second shaft section 102, and the outer diameters of the first shaft section 101 and the third shaft section 103 can be set to be equal. The gear body 120 is formed on the outer peripheral surface of the first shaft section 101, and the part of the first shaft section 101 away from the second shaft section 102 protrudes from the gear body 120. The external spline 140 is formed on the outer peripheral surface of the second shaft section 102. An annular process groove is formed between the first shaft section 101 and the second shaft section 102, and an annular process groove is formed between the second shaft section 102 and the third shaft section 103.

[0053] At the same time, the outer diameter of the gear body 120 is greater than the outer diameter of the external spline 140. The gear body 120 is configured as a helical gear, that is, the gear body 120 has a plurality of external teeth 121 evenly spaced and arranged in the circumferential direction thereof, and each external tooth 121 is arranged obliquely, that is, the length direction of each external tooth 121 has an angle with the axis of the shaft body 100, so that the tooth grooves defined between adjacent external teeth 121 are oblique tooth grooves 122. During the rotation of the gear body 120, when the lubricating oil moves to the oblique tooth grooves 122, it can move toward the bearing driven by the oblique tooth grooves 122, thereby effectively lubricating the bearing.

[0054] In this embodiment, optionally, the external spline 140 includes a plurality of external tooth bodies 141, the extension direction of each external tooth body 141 is consistent with the extension direction of the shaft body 100, and the plurality of external tooth bodies 141 are evenly spaced and arranged in the circumferential direction of the shaft body 100, and tooth grooves are formed between adjacent external tooth bodies 141. The structure of each external tooth body 141 is set to be the same, and in this embodiment, in order to avoid repeated description, the structure of one external tooth body 141 is taken as an example for description.

[0055] Please combine Figure 2-Figure 5Optionally, the portion of the outer tooth body 141 close to the third shaft segment 103 is set as an introduction segment 142, and the introduction segment 142 has an end close to the third shaft segment 103, which is called the guide end of the outer tooth body 141, and the end face of the guide end is called the guide end face 143. The width of the introduction segment 142 gradually decreases in the direction from the tooth root of the outer tooth body 141 to the tooth top of the outer tooth body 141, and the width of the introduction segment 142 gradually increases in the direction from the external spline 140 to the gear body 120. The guide end face 143 of the introduction segment 142 away from the gear body 120 is set as an arc surface, and the guide end face 143 protrudes from the end face of the second shaft segment 102 connected to the third shaft segment 103 in the axial direction of the shaft body 100. The guide end face 143 is designed to protrude from the end face of the second shaft section 102. During the press-fitting process of the gear shaft 001 and the intermediate gear 002, the third shaft section 103 gradually approaches the intermediate gear 002. The third shaft section 103 has a small outer diameter and a small coverage area, and the probability of collision with the intermediate gear 002 is small. The third shaft section 103 can smoothly enter the assembly inner hole of the intermediate gear 002, playing a role in preliminary positioning. As the press-fitting action proceeds further, the guide end face 143 of the introduction section 142 first contacts the internal spline 200. Since the guide end face 143 is convexly arranged on the end face of the second shaft section 102, the guide end face 143 can intervene in the guidance earlier and the guiding effect is better.

[0056] Furthermore, the tooth top surface 144 of the introduction section 142, that is, the outer side surface facing away from the second shaft section 102, is set as an arc surface. The tooth top surface 144 has an angle with the axis of the shaft body 100, and the distance between the tooth top surface 144 and the axis of the shaft body 100 gradually decreases in the direction from the gear body 120 to the external spline 140, and the lowest position of the tooth top surface 144 is not higher than the position of the tooth top circle of the external tooth body 141. Further, in this embodiment, there is an angle α between the tooth top surface 144 and the axis of the shaft body 100, wherein the angle α is set in the range of 15-30°, that is, the inclination angle of the tooth top surface 144 can be set in the range of 15-30°, for example, the inclination angle of the tooth top surface 144 can be set to 15°, 22°, 5° or 30°, etc. In this way, when the introduction section 142 is inserted into the internal spline 200 of the intermediate gear 002, the introduction section 142 first enters the assembly inner hole of the intermediate gear 002, and the guide end face 143 of the introduction section 142 first contacts the end of the internal spline 200 of the intermediate gear 002. Under the guidance of the guide end face 143, the gear shaft 001 can adaptively rotate relative to the intermediate gear 002 to achieve adaptive adjustment of the circumferential position, thereby reducing the probability of interference between the guide end face 143 and the end of the internal spline 200, which is conducive to the guide end face 143 entering the tooth groove of the internal spline 200. Then, as the introduction section 142 continues to be inserted into the internal spline 200, the arc-shaped tooth top surface 144 is in point contact with the internal spline 200, with a small contact area and low friction, and also has a guiding effect, so that the external spline 140 and the internal spline 200 are further aligned, and it is not easy to have a bias pressure that causes the spline end to be damaged. The press-fitting is convenient and reliable, and the internal spline 200 and the external spline 140 have a high quality of fit.

[0057] Furthermore, the introduction section 142 includes a first guide side surface 145 and a second guide side surface 146 which are symmetrically arranged in the circumferential direction of the shaft body 100, and the first guide side surface 145 and the second guide side surface 146 which are away from the second shaft section 102 are both close to the middle part of the external tooth body 141, so that the width of the introduction section 142 gradually decreases in the direction from the tooth root of the external tooth body 141 to the tooth top of the external tooth body 141. At the same time, the first guide side surface 145 and the second guide side surface 146 are both connected to the tooth top surface 144 of the introduction section 142, and the first guide side surface 145, the second guide side surface 146 and the tooth top surface 144 are converged on the side of the tooth top surface 144 close to the gear body 120, and the width of the portion where the tooth top surface 144 is simultaneously connected to the first guide side surface 145 and the second guide side surface 146 gradually increases in the direction from the gear body 120 to the external spline 140. When the introduction section 142 is inserted into the internal spline 200 of the intermediate gear 002 , both the first guide side surface 145 and the second guide side surface 146 can contact the internal spline 200 , playing a correction role and facilitating the radial direction of the press-fitting action.

[0058] The gear shaft 001 provided in this embodiment has a structural design of the introduction section 142. When the gear shaft 001 and the intermediate gear 002 are press-fitted, the guide end face 143 of the introduction section 142 first contacts the internal spline 200 of the intermediate gear 002. The contact area between the guide end face 143 and the internal spline 200 is small, and the formed obstruction is small, which is conducive to realizing the adaptive adjustment of the position of the gear shaft 001 and the internal spline 200 under the action of the press-fitting force, reducing the difficulty of assembly and improving the assembly efficiency. At the same time, the dependence on the press-fitting positioning tooling is reduced during the press-fitting process, reducing the cost.

[0059] Please combine Figure 6 and Figure 7 This embodiment also provides a gear transmission structure, which includes an intermediate gear 002 and the gear shaft 001 of the above embodiment, wherein the intermediate gear 002 is provided with an assembly inner hole, and an inner spline 200 is provided on the hole wall of the assembly inner hole, and the gear shaft 001 is inserted into the assembly inner hole, and the outer spline 140 on the gear shaft 001 is meshed with the inner spline 200. The gear transmission structure has high efficiency and low cost during assembly.

[0060] In this embodiment, optionally, the internal spline 200 includes a plurality of internal teeth arranged at intervals around the axis of the intermediate gear 002, and the plurality of external teeth 141 and the plurality of internal teeth are arranged alternately in the circumferential direction of the intermediate gear 002; the external teeth 141 have two ends in the axial direction of the intermediate gear 002, and at least one of the two ends is provided with a chamfer 201. The chamfer 201 can be a rounded corner or a chamfered corner. The press-fitting quality can be further improved by the cooperation between the external spline 140 and the internal spline 200.

[0061] This embodiment also provides a gear box, which includes the gear transmission structure of the above embodiment and has at least the advantages of simple assembly and low cost.

[0062] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A gear shaft, used to cooperate with an intermediate gear (002) having an internal spline (200), characterized in that: include: A shaft body (100), a gear body (120) and an external spline (140), wherein the gear body (120) and the external spline (140) are both formed on the outer peripheral surface of the shaft body (100), and the gear body (120) and the external spline (140) are arranged in the axial direction of the shaft body (100); the gear body (120) is provided with an oblique tooth groove (122) for guiding oil; the external spline (140) includes a plurality of external tooth bodies (141), and the plurality of external tooth bodies (141) are arranged at intervals around the axis of the shaft body (100); an introduction section (142) is provided at one end of the external tooth body (141) away from the shaft body (100), and the external spline (140) is used to be inserted into the intermediate gear (002) through the introduction section (142), so that the external spline (140) is meshed with the internal spline (200); The width of the introduction section (142) gradually decreases in the direction from the tooth root of the external tooth body (141) to the tooth top of the external tooth body (141), and the width of the introduction section (142) gradually increases in the direction from the external spline (140) to the gear body (120); the guide end surface (143) of the introduction section (142) away from the gear body (120) is set as an arc surface; wherein the width direction of the introduction section (142) is consistent with the circumferential direction of the shaft body (100).

2. The gear shaft according to claim 1, characterized in that: The tooth top surface (144) of the introduction section (142) is configured as an arc-shaped surface.

3. The gear shaft according to claim 2, characterized in that: The tooth top surface (144) has an included angle with the axis of the shaft body (100), and the distance between the tooth top surface (144) and the axis of the shaft body (100) gradually decreases in the direction from the gear body (120) to the external spline (140), and the lowest position of the tooth top surface (144) is not higher than the position of the tooth top circle of the external tooth body (141).

4. The gear shaft according to claim 3, characterized in that: The angle between the tooth top surface (144) and the axis of the shaft body (100) is set between 15-30 degrees.

5. The gear shaft according to any one of claims 1 to 4, characterized in that: The shaft body (100) comprises a first shaft segment (101), a second shaft segment (102) and a third shaft segment (103) which are connected in sequence; the outer diameter of the second shaft segment (102) is larger than the outer diameters of the first shaft segment (101) and the third shaft segment (103); the gear body (120) is arranged on the outer peripheral surface of the first shaft segment (101); the external spline (140) is arranged on the outer peripheral surface of the second shaft segment (102); and the guide end surface (143) protrudes from the end surface of the second shaft segment (102) which is connected to the third shaft segment (103).

6. The gear shaft according to claim 1, characterized in that: The introduction section (142) comprises a first guide side surface (145) and a second guide side surface (146), the first guide side surface (145) and the second guide side surface (146) are arranged in the width direction of the introduction section (142), the first guide side surface (145) and the second guide side surface (146) are both connected to the tooth top surface (144) of the introduction section (142), the first guide side surface (145), the second guide side surface (146) and the tooth top surface (144) converge on a side of the tooth top surface (144) close to the gear body (120), and the width of a portion where the tooth top surface (144) is connected to both the first guide side surface (145) and the second guide side surface (146) gradually increases in a direction from the gear body (120) toward the external spline (140).

7. A gear transmission structure, characterized in that: The gear transmission structure comprises: An intermediate gear (002) and a gear shaft (001) according to any one of claims 1 to 6, wherein the intermediate gear (002) is provided with an assembly inner hole, an internal spline (200) is provided on the hole wall of the assembly inner hole, the gear shaft (001) is inserted into the assembly inner hole, and the external spline (140) on the gear shaft (001) is meshed with the internal spline (200).

8. The gear transmission structure according to claim 7, characterized in that: The internal spline (200) includes a plurality of internal tooth bodies arranged at intervals around the axis of the intermediate gear (002), and the plurality of external tooth bodies (141) and the plurality of internal tooth bodies are alternately arranged in sequence in the circumferential direction of the intermediate gear (002); the external tooth body (141) has two end portions in the axial direction of the intermediate gear (002), and at least one of the two end portions is provided with a chamfer (201).

9. The gear transmission structure according to claim 8, characterized in that: The chamfer (201) is configured as a rounded corner or a chamfered corner.

10. A gear box, characterized in that: The gearbox comprises: The gear transmission structure according to any one of claims 7 to 9.

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