1. The utility model provides a glued structure is prevented to planetary gear's hole, characterized by, the axial cross-section profile of planetary gear's hole wall includes:

the middle section (1), the shape of the middle section (1) is a line segment, and the hole wall of an inner hole corresponding to the middle section (1) is used for being matched with a planet shaft;

the end face section (2), the middle section (1) and the planet gear end face are connected to the end face section (2), and the end face section (2) is a section of parabola or logarithmic function curve protruding towards the inner hole axis.

2. A planetary gear inner bore anti-gluing structure according to claim I, wherein the equation of the shape of the end surface section (2) is:

f(x)＝C(x/L)²+Dx+E；

in the formula: C. d, E is an empirical coefficient; x is the coordinate of the end surface section (2) from the joint (zero point) of the middle section (1) to each point of the end surface joint, which is parallel to the axis of the inner hole and is in unit mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point, perpendicular to the axis of the inner hole, from the joint (zero point) of the middle section (1) to the joint of the end face section (2) in the unit of mum.

3. A planetary gear inner bore anti-gluing structure according to claim 1, wherein the equation of the shape of the end surface section (2) is:

in the formula: A. b is an empirical coefficient; x is the coordinate of the end surface section (2) from the joint (zero point) of the middle section (1) to each point of the end surface joint, which is parallel to the axis of the inner hole and is in unit mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point, perpendicular to the axis of the inner hole, from the joint (zero point) of the middle section (1) to the joint of the end face section (2) in the unit of mum.

4. The inner hole gluing prevention structure of the planetary gear as claimed in claim I, wherein the ratio of the projection length of the end surface section (2) on the inner hole axis to the projection length of the middle section (1) on the inner hole axis is 0.05-0.35.

5. The inner hole gluing prevention structure of the planetary gear as claimed in claim 1, wherein the maximum value of the inner hole aperture corresponding to the end face section (2) is 50 μm to 1500 μm larger than the inner hole aperture corresponding to the middle section (1).

6. A planetary gear inner bore anti-gluing structure as claimed in any one of claims 1 to 5, wherein the inner bore wall corresponding to the middle section (1) is provided with a wear-resistant coating.

7. A planetary gear inner bore anti-seize structure as claimed in any one of claims 1 to 5, wherein the corresponding inner bore wall surface of the end face section (2) is a surface which is finely ground and polished.

Background

The planetary gear in the differential mechanism of automobile is a transmission part under the working condition of low speed and heavy load, and its internal hole and planetary shaft matched with it are a pair of friction rotating pairs. When the planet gear rotates around the planet shaft, enough lubricating oil must enter between the planet gear and the planet shaft to ensure that the planet gear and the planet shaft work normally, otherwise, dry friction occurs between the planet gear and the planet shaft, and abnormal high temperature is generated by a friction by-product, so that the planet gear and the planet shaft are glued, and even the planet gear and the planet shaft are bonded when the friction is serious. In the prior art, the inner hole of the planetary gear is a round straight hole, the two ends of the inner hole are chamfered and are in clearance fit with the planetary shaft, and lubricating oil in the clearance can meet the use requirement under the normal working condition. When the automobile is under a heavy load condition, the unit area load of the contact surface of the planetary gear and the planetary shaft is large, the lubricating oil in the gap cannot meet the lubricating requirement, and the friction pair is easy to overheat to cause gluing.

Some inventors have proposed some solutions to the above problems, for example, the utility model with the name of "planetary gear inner hole anti-bonding structure" disclosed in publication No. CN202209393U, the axial cross section of the inner hole wall of the planetary gear is an inward convex arc, the inner diameter between the highest points of the arc protrusions at both sides is equal to the nominal size and tolerance, and the inner diameter of the hole at both ends gradually increasing along the arc is greater than the nominal size by 0.01mm to 0.06 mm. The structure is beneficial to the infiltration of lubricating oil from the two ends of the inner hole of the planetary gear, and the adhesion of a friction pair caused by dry friction due to the insufficient lubricating oil is avoided. However, the contact stress between the planet gear and the matched shaft is easily overlarge due to the design of the inward convex arc-shaped structure, and a narrow region at the highest position of the inner hole bulge of the planet gear is firstly contacted with the matched shaft during bearing, so that a higher stress peak value is generated in the middle of the matched shaft. Excessive stress can lead to oil film fracture and further lead to increased abrasion of the planetary gear and the matched shaft in a contact area, and can also increase the risk of damage of the planetary gear and the matched shaft when heavy load or impact is applied.

Disclosure of Invention

The invention aims to provide an inner hole gluing prevention structure of a planetary gear, wherein the inner hole structure is favorable for lubricating oil to permeate from two ends of an inner hole; the contact area between the inner hole and the planet shaft is large, and the contact stress between the planet gear and the planet shaft during bearing can be reduced.

The technical scheme of the invention is as follows:

an anti-gluing structure for an inner hole of a planetary gear, the axial cross-sectional profile of the inner hole wall of the planetary gear comprising:

the middle section is in a line segment shape, and the hole wall of an inner hole corresponding to the middle section is used for being matched with the planet shaft;

the end face section is connected with the middle section and the end face of the planetary gear and is in the shape of a section of parabola or logarithmic function curve protruding towards the axis of the inner hole.

The gluing structure is prevented to planetary gear's hole of this scheme, interlude shape is the line segment, and the hole pore wall that the interlude corresponds is used for cooperating with the planet axle, and the regional contact with the planet axle of the interlude of planetary gear hole when bearing ensures that planetary gear hole and planet axle have sufficient area of contact, and the contact stress of planetary gear and planet axle is too big when avoiding bearing. The terminal surface section is connected interlude and planetary gear terminal surface, and the terminal surface section shape is one section parabola or logarithmic function curve protruding towards the hole axis, and the shape of terminal surface section more is close streamlined, is favorable to lubricating oil to permeate from hole both ends, makes the formation oil film between planetary gear and the planet axle easily, reduces the two risk that takes place dry friction and lead to the veneer.

Preferably, the equation for the shape of the end face section is:

f(x)＝C(x/L)²+Dx+E；

in the formula: C. d, E is an empirical coefficient; x is the coordinate of each point parallel to the axis of the inner hole from the middle section joint (zero point) to the end surface joint of the end surface section, and the unit is mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point of the end surface section from the middle section joint (zero point) to the end surface joint, which is vertical to the axis of the inner hole and has the unit of mum. The parabolic equation is simple to calculate and high in precision, and the shape of the end face section is a section of parabola, so that the machining precision of the inner hole wall corresponding to the end face section can be controlled.

Preferably, the equation for the shape of the end face section is:

in the formula: A. b is an empirical coefficient; x is the coordinate of each point parallel to the axis of the inner hole from the middle section joint (zero point) to the end surface joint of the end surface section, and the unit is mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point of the end surface section from the middle section joint (zero point) to the end surface joint, which is vertical to the axis of the inner hole and has the unit of mum. The slope change of the logarithmic function curve is obvious, the maximum value of the hole diameter of the inner hole corresponding to the end surface section is larger under the same condition, and the shape of the end surface section is a section of logarithmic function curve, so that the promotion effect of lubricating oil permeating from the two ends of the inner hole is improved.

Preferably, the ratio of the projection length of the end surface section on the inner hole axis to the projection length of the middle section on the inner hole axis is 0.05-0.35. The larger the projection length of the end surface section on the axis of the inner hole is, the more favorable the lubricating oil is to permeate from the two ends of the inner hole, and the more favorable the dry friction between the planetary gear and the planetary shaft can be avoided. The larger the projection length of the middle section on the axis of the inner hole is, the larger the contact area of the inner hole of the planetary gear and the planetary shaft is, and the smaller the contact stress of the inner hole and the planetary shaft is. The two requirements are in conflict, so the ratio of the projection length of the end surface section on the inner hole axis to the projection length of the middle section on the inner hole axis is properly selected according to the situation.

Preferably, the maximum value of the bore diameter corresponding to the end face section is 50-1500 μm larger than the bore diameter corresponding to the middle section. The difference value of the bore diameter maximum value corresponding to the end face section and the bore diameter corresponding to the middle section is increased in a certain range, so that lubricating oil can permeate from the two ends of the bore, the contact area between the planetary gear and the planetary shaft during heavy load can be reduced when the value is continuously increased, the contact stress during heavy load is increased, and therefore the value comprehensively takes the proper value of the promoting effect of lubricating oil permeating from the two ends of the bore and the working condition of the planetary gear.

Preferably, the inner hole wall surface corresponding to the intermediate section is a surface after phosphating treatment. The inner hole wall surface corresponding to the middle section is a surface after phosphating treatment, a phosphating layer can be formed on the surface of the middle section after phosphating treatment, the phosphating layer has a self-lubricating effect, the friction coefficient of the contact surface of the planet shaft and the planet gear can also be reduced, the abrasion of the planet gear is favorably reduced, and the service life of the planet gear is prolonged.

Preferably, the inner hole wall surface corresponding to the end surface section is a surface after fine grinding treatment. The inner hole wall surface corresponding to the end surface section is a surface after fine grinding treatment, so that the viscous resistance of lubricating oil when penetrating from the two ends of the inner hole can be reduced, and the lubricating oil is favorable for penetrating from the two ends of the inner hole.

The invention has the beneficial effects that: the shape of the end surface section is beneficial to the infiltration of lubricating oil from two ends of an inner hole, so that an oil film is easily formed between the planetary gear and the planetary shaft, and the risk of gluing the planetary gear and the planetary shaft due to dry friction is reduced; the middle section area of the inner hole of the planet gear is contacted with the planet shaft during bearing, so that the sufficient contact area between the inner hole of the planet gear and the planet shaft is ensured, and the overlarge contact stress between the planet gear and the planet shaft during bearing is avoided.

Drawings

FIG. 1 is a schematic diagram of the present invention.

FIG. 2 is a schematic view of a planetary gear bore of the prior art.

Figure 3 is a schematic view of the planetary gear inner bore of the patent publication CN 202209393U.

FIG. 4 is a schematic view of the contact stress of the inner hole wall of the planetary gear under light load.

FIG. 5 is a schematic view of the contact stress of the inner hole wall of the planetary gear under light load in the prior art.

FIG. 6 is a schematic view showing the contact stress of the planetary gear inner hole wall at light load in the patent publication No. CN 202209393U.

FIG. 7 is a schematic view of the contact stress of the inner hole wall of the planetary gear in heavy load according to the present invention.

FIG. 8 is a schematic view of the contact stress of the inner hole wall of the planetary gear under heavy load in the prior art.

FIG. 9 is a schematic view showing the contact stress of the inner hole wall of the planetary gear at the time of heavy load in the patent publication No. CN 202209393U.

FIG. 10 is a partial schematic view of the present invention in a coordinate system.

In the figure:

a middle section 1;

end face section 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are clearly explained and illustrated below with reference to the accompanying drawings, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present invention.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present scheme, and are not construed as limiting the scheme of the present invention.

These and other aspects of embodiments of the invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the embodiments of the invention may be practiced, but it is understood that the scope of the embodiments of the invention is not limited thereby. On the contrary, the embodiments of the invention include all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto.

In the description of the present invention, it is to be understood that the terms "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., and "several" means one or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral connections, either mechanical or electrical, or communicating with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The first embodiment is as follows: as shown in fig. 1 to 10, an inner hole anti-gluing structure of a planetary gear, an axial cross-sectional profile of an inner hole wall of the planetary gear includes:

the middle section 1 is in a line shape, and the hole wall of an inner hole corresponding to the middle section 1 is matched with the planet shaft;

the end face section 2 is connected with the middle section 1 and the end face of the planetary gear, and the end face section 2 is in the shape of a parabola protruding towards the axis of the inner hole.

In the inner hole gluing prevention structure of the planetary gear, the middle section 1 is a line segment, the hole wall of the inner hole corresponding to the middle section 1 is used for being matched with a planetary shaft, the middle section 1 area of the inner hole of the planetary gear is contacted with the planetary shaft during bearing, so that the sufficient contact area between the inner hole of the planetary gear and the planetary shaft is ensured, and the overlarge contact stress between the planetary gear and the planetary shaft during bearing is avoided (specifically, fig. 4 and 6 can be compared with fig. 7 and 9). The end face section 2 is connected with the middle section 1 and the end face of the planetary gear, the shape of the end face section 2 is a parabola protruding towards the axis of the inner hole, the shape of the end face section 2 is more close to streamline, lubricating oil is favorably infiltrated from two ends of the inner hole, an oil film is easily formed between the planetary gear and the planetary shaft, and the risk that the dry friction causes gluing is reduced.

Further, the equation for the shape of the end face section 2 is: f (x) C (x/L)²+Dx+E；

In the formula: C. d, E is an empirical coefficient; x is the coordinate of each point parallel to the axis of the inner hole from the joint (zero point) of the middle section 1 to the joint of the end face section 2, and the unit is mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point of the end surface section 2 from the connecting part (zero point) of the middle section 1 to the connecting part of the end surface, which is vertical to the axis of the inner hole and has the unit of mum. The parabolic equation is simple to calculate and high in precision, and the shape of the end surface section 2 is a section of parabola, so that the processing precision of the inner hole wall corresponding to the end surface section 2 can be controlled.

Furthermore, the ratio of the projection length of the end surface section 2 on the inner hole axis to the projection length of the middle section 1 on the inner hole axis is 0.05-0.35. The larger the projection length of the end surface section 2 on the axis of the inner hole is, the more favorable the lubricating oil is to penetrate from the two ends of the inner hole, and the more favorable the dry friction between the planetary gear and the planetary shaft can be avoided. The larger the projection length of the middle section 1 on the inner hole axis is, the larger the contact area of the inner hole of the planetary gear and the planetary shaft is, and the smaller the contact stress of the inner hole and the planetary shaft is. The two requirements are in conflict, so the ratio of the projection length of the end surface section 2 on the inner hole axis to the projection length of the middle section 1 on the inner hole axis is properly selected according to the situation.

Furthermore, the maximum value of the bore diameter of the inner bore corresponding to the end face section 2 is 50-1500 μm larger than that of the inner bore corresponding to the middle section 1. The difference value of the bore diameter maximum value corresponding to the end surface section 2 and the bore diameter corresponding to the middle section 1 is increased in a certain range, so that lubricating oil can permeate from the two ends of the bore, the contact area between the planetary gear and the planetary shaft during heavy load can be reduced when the value is continuously increased, and the contact stress during heavy load is increased, so that the value comprehensively takes the proper value of the promotion effect of the lubricating oil permeating from the two ends of the bore and the working condition of the planetary gear.

Furthermore, the wall surface of the inner hole corresponding to the middle section 1 is a surface after phosphating treatment. The inner hole wall surface corresponding to the middle section 1 is a surface after phosphating treatment, a phosphating layer can be formed on the surface after phosphating treatment, the phosphating layer has a self-lubricating effect, the friction coefficient of the contact surface of the planet shaft and the planet gear can be reduced, the abrasion of the planet gear is reduced, and the service life of the planet gear is prolonged.

Further, the inner hole wall surface corresponding to the end surface section 2 is a surface after fine grinding treatment. The inner hole wall surface corresponding to the end surface section 2 is a surface after fine grinding treatment, so that the viscous resistance of lubricating oil when penetrating from the two ends of the inner hole can be reduced, and the lubricating oil is favorable for penetrating from the two ends of the inner hole.

The second embodiment is as follows: as shown in fig. 1 to 10, an inner hole anti-gluing structure of a planetary gear, an axial cross-sectional profile of an inner hole wall of the planetary gear includes:

the middle section 1 is in a line shape, and the hole wall of an inner hole corresponding to the middle section 1 is matched with the planet shaft;

the end face section 2 is connected with the middle section 1 and the end face of the planetary gear, and the end face section 2 is in the shape of a logarithmic function curve protruding towards the axis of the inner hole.

In the inner hole gluing prevention structure of the planetary gear, the middle section 1 is a line segment, the hole wall of the inner hole corresponding to the middle section 1 is used for being matched with a planetary shaft, the middle section 1 area of the inner hole of the planetary gear is contacted with the planetary shaft during bearing, so that the sufficient contact area between the inner hole of the planetary gear and the planetary shaft is ensured, and the overlarge contact stress between the planetary gear and the planetary shaft during bearing is avoided (specifically, fig. 4 and 6 can be compared with fig. 7 and 9). The terminal surface section 2 is connected interlude 1 and planetary gear terminal surface, and terminal surface section 2 shape is one section logarithmic function curve protruding towards the hole axis, and terminal surface section 2's shape is more close streamlined, is favorable to lubricating oil to form the oil film from hole both ends infiltration, makes planetary gear and planet axle between easy, reduces the two risk that takes place dry friction and lead to the veneer.

Further, the equation for the shape of the end face section 2 is:

in the formula: A. b is an empirical coefficient; x is the coordinate of each point parallel to the axis of the inner hole from the joint (zero point) of the middle section 1 to the joint of the end face section 2, and the unit is mm; l is the length of the inner hole of the planetary gear, and the unit is mm; and f (x) is the coordinate of each point of the end surface section 2 from the connecting part (zero point) of the middle section 1 to the connecting part of the end surface, which is vertical to the axis of the inner hole and has the unit of mum. The slope change of the logarithmic function curve is obvious, the maximum value of the hole diameter of the inner hole corresponding to the end surface section is larger under the same condition, and the shape of the end surface section 2 is a section of logarithmic function curve, which is favorable for improving the promotion effect of lubricating oil permeating from the two ends of the inner hole.

Furthermore, the ratio of the projection length of the end surface section 2 on the inner hole axis to the projection length of the middle section 1 on the inner hole axis is 0.05-0.35. The larger the projection length of the end surface section 2 on the axis of the inner hole is, the more favorable the lubricating oil is to penetrate from the two ends of the inner hole, and the more favorable the dry friction between the planetary gear and the planetary shaft can be avoided. The larger the projection length of the middle section 1 on the inner hole axis is, the larger the contact area of the inner hole of the planetary gear and the planetary shaft is, and the smaller the contact stress of the inner hole and the planetary shaft is. The two requirements are in conflict, so the ratio of the projection length of the end surface section 2 on the inner hole axis to the projection length of the middle section 1 on the inner hole axis is properly selected according to the situation.

Furthermore, the maximum value of the bore diameter of the inner bore corresponding to the end face section 2 is 50-1500 μm larger than that of the inner bore corresponding to the middle section 1. The difference value of the bore diameter maximum value corresponding to the end surface section 2 and the bore diameter corresponding to the middle section 1 is increased in a certain range, so that lubricating oil can permeate from the two ends of the bore, the contact area between the planetary gear and the planetary shaft during heavy load can be reduced when the value is continuously increased, and the contact stress during heavy load is increased, so that the value comprehensively takes the proper value of the promotion effect of the lubricating oil permeating from the two ends of the bore and the working condition of the planetary gear.

Furthermore, the wall surface of the inner hole corresponding to the middle section 1 is a surface after phosphating treatment. The inner hole wall surface corresponding to the middle section 1 is a surface after phosphating treatment, a phosphating layer can be formed on the surface after phosphating treatment, the phosphating layer has a self-lubricating effect, the friction coefficient of the contact surface of the planet shaft and the planet gear can be reduced, the abrasion of the planet gear is reduced, and the service life of the planet gear is prolonged.

Further, the inner hole wall surface corresponding to the end surface section 2 is a surface after fine grinding treatment. The inner hole wall surface corresponding to the end surface section 2 is a surface after fine grinding treatment, so that the viscous resistance of lubricating oil when penetrating from the two ends of the inner hole can be reduced, and the lubricating oil is favorable for penetrating from the two ends of the inner hole.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.