Crankshaft assembly, RV speed reducer and industrial robot

Abstract

The invention discloses a crankshaft assembly, an RV speed reducer and an industrial robot, and relates to the technical field of speed reducers, the crankshaft assembly comprises a middle part, a first eccentric part, a second eccentric part, a first gasket, a first bearing and a second bearing, and a first eccentric groove and a second eccentric groove are formed in the two ends of the middle part respectively; the first eccentric part and the middle part are eccentrically arranged; the second eccentric part and the middle part are eccentrically arranged; the first gasket is sleeved on the middle part; the first bearing is installed on the first eccentric part and abuts against the first gasket. The second bearing is installed on the second eccentric part and abuts against the first gasket. By arranging the first gasket, abrasion of the first bearing and the second bearing is reduced, and the service life of the crankshaft assembly is prolonged; the outer diameter of the middle part is reasonably limited, and the first eccentric groove and the second eccentric groove are matched, so that the first bearing and the second bearing stably move while the first gasket is conveniently positioned and mounted, and the structural rationality of the middle part is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a crankshaft assembly, an RV reducer and an industrial robot. Background Art

[0002] RV reducers are precision reducers widely used in the field of high-precision transmission. The crankshaft assembly is a crucial transmission component in RV reducers, which mainly plays the role of transmitting power. The service life of the crankshaft assembly directly determines the service life of the RV reducer. In the prior art RV reducers, the cycloid wheel inside is mainly installed on the eccentric part of the crankshaft assembly through a needle bearing. This easily leads to the needle bearings on the inner side of the two adjacent cycloid wheels colliding and rubbing against each other when the RV reducer is working, increasing the friction loss of the crankshaft assembly, affecting the service life of the crankshaft assembly and the transmission accuracy of the crankshaft assembly. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a crankshaft assembly, which separates a first bearing and a second bearing by providing a first gasket, avoids the first bearing by providing a first eccentric groove, and avoids the second bearing by providing a second eccentric groove, thereby avoiding mutual friction between the first bearing and the second bearing, reducing wear of the first bearing and the second bearing, and effectively extending the service life of the crankshaft assembly.

[0004] The present invention also provides an RV reducer having the crankshaft assembly.

[0005] The present invention also provides an industrial robot having the RV reducer.

[0006] A crankshaft assembly according to a first embodiment of the present invention comprises:

[0007] An intermediate portion, a first eccentric portion, a second eccentric portion, a first gasket, a first bearing and a second bearing, wherein the intermediate portion is provided with a first eccentric groove and a second eccentric groove at two ends along the rotation axis, respectively, and the outer diameter of the intermediate portion is e; the first eccentric portion is connected to one end of the intermediate portion provided with the first eccentric groove, and is eccentrically arranged with the intermediate portion, the first central axis of the first eccentric portion is parallel to the rotation axis and the offset is b1, and the outer diameter of the first eccentric portion is g1; the second eccentric portion is connected to one end of the intermediate portion provided with the second eccentric groove, and is eccentrically arranged with the intermediate portion, the second central axis of the second eccentric portion is parallel to the rotation axis of the intermediate portion and the offset is b2, and the outer diameter of the second eccentric portion is g2; the first gasket is sleeved on the intermediate portion and can rotate relative to the intermediate portion; the first bearing is mounted on the first eccentric portion, and abuts against the first gasket; the second bearing is mounted on the second eccentric portion, and abuts against the first gasket;

[0008] Wherein, projected along the direction of the rotation axis, the projection of the first bottom wall of the first eccentric groove and the projection of part of the peripheral wall of the middle part form a first contour line around the rotation axis, and the first contour line is located within the projection of the first eccentric part; the projection of the second bottom wall of the second eccentric groove and the projection of part of the peripheral wall of the middle part form a second contour line around the rotation axis, and the second contour line is located within the projection of the second eccentric part; and satisfying: (1 / 2)*g1+(1 / 2)*g2-b1-b2<e<(1 / 2)*g1+b1+b2+(1 / 2)*g2.

[0009] The crankshaft assembly according to the embodiment of the present invention has at least the following beneficial effects:

[0010] By setting the first gasket, after the crankshaft assembly is assembled, the first bearing installed on the first eccentric part abuts against one side of the first gasket, and the second bearing installed on the second eccentric part abuts against the other side of the first gasket. During the rotation of the crankshaft assembly, the first gasket rotates relative to the middle part, and the two sides of the first gasket respectively abut and rub against the first bearing and the second bearing, thereby absorbing the impact of the first bearing and the second bearing, reducing the wear of the first bearing and the second bearing, extending the service life of the crankshaft assembly, and ensuring the transmission accuracy of the crankshaft assembly; by setting the first eccentric groove and the second eccentric groove, a first contour line formed by the projection of the first eccentric groove and the projection of part of the peripheral wall is projected along the direction of the rotation axis and is located within the projection of the first eccentric part, that is, along the radial direction of the middle part, the peripheral wall of one end of the middle part provided with the first eccentric groove is located in the first eccentric part The inner side of the peripheral wall can avoid interference between the end face of the middle part and the first bearing installed on the first eccentric part. Similarly, the second contour line surrounded by the projection of the second eccentric groove and the projection of part of the peripheral wall is located within the projection of the second eccentric part, which can avoid interference between the end face of the middle part and the second bearing installed on the second eccentric part. The outer diameter e of the middle part is limited to between (1 / 2)*g1+(1 / 2)*g2-b1-b2 and (1 / 2)*g1+b1+b2+(1 / 2)*g2, that is, along the radial direction of the middle part, the peripheral wall of the middle part is limited between the peripheral wall of the first eccentric part and the peripheral wall of the second eccentric part, and the first eccentric groove for avoiding the first bearing and the second eccentric groove for avoiding the second bearing are used to facilitate the positioning and installation of the first gasket while ensuring the stable movement of the first bearing and the second bearing, thereby effectively improving the structural rationality of the middle part.

[0011] According to some embodiments of the present invention, the first bearing includes a first retaining frame, and the second bearing includes a second retaining frame. Along the direction of the rotation axis, the first retaining frame protrudes from the end surface of the first eccentric portion toward the middle portion, and the second retaining frame protrudes from the end surface of the second eccentric portion toward the middle portion. Both ends of the first gasket respectively abut the first retaining frame and the second retaining frame.

[0012] According to some embodiments of the present invention, the thickness of the first gasket is m, and the width of the middle portion is d, satisfying: 1mm≤m<(2 / 3)d.

[0013] According to some embodiments of the present invention, along the radial direction of the first gasket, the distance that the first gasket exceeds the outer circumference of the first bearing is n1, and the distance that the first gasket exceeds the outer circumference of the second bearing is n2, satisfying: n1≥0, n2≥0.

[0014] According to some embodiments of the present invention, the width of the middle portion is d, the width of the first eccentric groove is c1, and the width of the second eccentric groove is c2, satisfying: 2*c1<d≤4*c1, 2*c2<d≤4*c2.

[0015] According to some embodiments of the present invention, a width c1 of the first eccentric groove is equal to a width c2 of the second eccentric groove.

[0016] According to some embodiments of the present invention, the first bottom wall is configured as a first arc surface whose rotation center is the first central axis, and the diameter of the first arc surface is f1, satisfying: f1<g1.

[0017] According to some embodiments of the present invention, the second bottom wall is configured as a second arc surface whose rotation center is the second central axis, and the diameter of the second arc surface is f2, satisfying: f2<g2.

[0018] According to some embodiments of the present invention, the crank shaft assembly also includes a first support portion and a second support portion coaxially arranged with the middle portion, as well as a second gasket, a third gasket, a third bearing and a fourth bearing, the first support portion is connected to the first eccentric portion, the second support portion is connected to the second eccentric portion, the third bearing is installed on the first support portion, the fourth bearing is installed on the second support portion, the second gasket is sleeved on the first support portion and its two ends respectively abut against the end faces of the third bearing and the first eccentric portion, the third gasket is sleeved on the second support portion and its two ends respectively abut against the end faces of the fourth bearing and the second eccentric portion.

[0019] According to some embodiments of the present invention, the distance between the end surface of the first support portion away from the first eccentric portion and the end surface of the second support portion away from the second eccentric portion is h1, and the maximum distance between the third bearing and the fourth bearing is h2, satisfying: h1>h2.

[0020] According to some embodiments of the present invention, the distance between the end surface of the first eccentric portion away from the middle portion and the end surface of the second eccentric portion away from the middle portion is j1, and the maximum distance between the first bearing and the second bearing is j2, satisfying: j1>j2.

[0021] According to some embodiments of the present invention, the second gasket is capable of rotating relative to the first supporting portion, and along the radial direction of the second gasket, the distance that the second gasket exceeds the outer peripheral edge of the third bearing is k1, satisfying: k1≥2mm; and / or, the third gasket is capable of rotating relative to the second supporting portion, and along the radial direction of the third gasket, the distance that the third gasket exceeds the outer peripheral edge of the fourth bearing is k2, satisfying: k2≥2mm.

[0022] The RV reducer according to the second embodiment of the present invention includes the crankshaft assembly described in the above embodiment.

[0023] The RV reducer according to the embodiment of the present invention has at least the following beneficial effects:

[0024] The crankshaft assembly of the first aspect embodiment is adopted, and the crankshaft assembly reduces the wear of the first bearing and the second bearing, extends the service life of the crankshaft assembly, and ensures the transmission accuracy of the crankshaft assembly by setting an intermediate portion and installing a first gasket on the intermediate portion; by reasonably limiting the size of the intermediate portion, cooperating with the first eccentric groove for avoiding the first bearing and the second eccentric groove for avoiding the second bearing, while facilitating the positioning and installation of the first gasket, the stable movement of the first bearing and the second bearing is ensured, thereby effectively improving the structural rationality of the intermediate portion.

[0025] The industrial robot according to the third aspect of the present invention comprises the RV reducer described in the above embodiment.

[0026] The industrial robot according to the embodiment of the present invention has at least the following beneficial effects:

[0027] The RV reducer of the industrial robot, the crankshaft assembly reduces the wear of the first bearing and the second bearing, extends the service life of the crankshaft assembly, and ensures the transmission accuracy of the crankshaft assembly by setting an intermediate part and installing the first gasket on the intermediate part; by reasonably limiting the size of the intermediate part, cooperating with the first eccentric groove for avoiding the first bearing and the second eccentric groove for avoiding the second bearing, while facilitating the positioning and installation of the first gasket, the first bearing and the second bearing are ensured to move stably, effectively improving the structural rationality of the intermediate part.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0030] Figure 1 A schematic structural diagram of a crankshaft assembly according to an embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the assembly of a crankshaft assembly according to an embodiment of the present invention;

[0032] Figure 3 for Figure 2 Annotated drawing of radial dimensions of the middle crankshaft assembly;

[0033] Figure 4 for Figure 2 Annotated drawing of the axial dimensions of the middle crankshaft assembly;

[0034] Figure 5 for Figure 1 The cross-section at A in the middle;

[0035] Figure 6 for Figure 1 The cross-sectional view at B in the middle;

[0036] Figure 7 for Figure 3 Enlarged view of point C in the middle;

[0037] Figure 8 for Figure 3 Enlarged view of point D in the middle.

[0038] Figure numbers: middle part 100; first eccentric groove 101; first arc surface 1011; first contour line 1012; second eccentric groove 102; second arc surface 1021; second contour line 1022; first processing section 110; second processing section 120; positioning section 130; first eccentric part 200; first bearing 210; first retaining frame 211; first crescent 220; second crescent 230; second eccentric part 300; second bearing 310; second retaining frame 311; third crescent 320; fourth crescent 330; first gasket 400; first support part 500; third bearing 510; second support part 600; fourth bearing 610; second gasket 700; third gasket 800. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0040] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0041] In the description of the present invention, "a plurality" means more than two. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0042] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0043] Reference Figures 1 to 3 As shown, an RV reducer according to an embodiment of the present invention comprises an intermediate portion 100, a first eccentric portion 200, a second eccentric portion 300, a first gasket 400, a first bearing 210 and a second bearing 310. The intermediate portion 100 is provided with a first eccentric groove 101 and a second eccentric groove 102 at both ends along the rotation axis a0, respectively. The first eccentric groove 101 and the second eccentric groove 102 divide the intermediate portion 100 into a first processing section 110, a second processing section 120 and a positioning section 130 between the first processing section 110 and the second processing section 120. The first eccentric groove 101 is formed on one side of the first processing section 110, and the second eccentric groove 102 is formed on one side of the second processing section 120. The outer diameter of the middle part 100 at the positioning section 130 is e, that is, when the first eccentric groove 101 and the second eccentric groove 102 are not processed, the middle part 100 is a cylinder with an outer diameter of e, and the first gasket 400 is mounted on the positioning section 130. The inner hole (not shown in the figure) of the first gasket 400 and the positioning section 130 are clearance-matched to enable the first gasket 400 to rotate relative to the middle part 100.

[0044] The first eccentric portion 200 is connected to the first processing section 110 provided with the first eccentric groove 101, and the first eccentric portion 200 is eccentrically arranged with the middle portion 100, that is, the first central axis a1 of the first eccentric portion 200 is parallel to the rotation axis a0 but not colinear, and the offset of the first central axis a1 and the rotation axis a0 is b1, that is, along the radial direction of the positioning section 130, the distance between the first central axis a1 and the rotation axis a0 is b1; the second eccentric portion 300 is connected to the second processing section 120 provided with the second eccentric groove 102, and the second eccentric portion 300 is eccentrically arranged with the middle portion 100, that is, the second central axis a2 of the second eccentric portion 300 is parallel to the rotation axis a0 but not colinear, and the offset of the second central axis a2 and the rotation axis a0 is b2, that is, along the radial direction of the positioning section 130, the distance between the second central axis a2 and the rotation axis a0 is b2.

[0045] Reference Figure 2 As shown, it can be understood that the first bearing 210 includes a first retaining frame 211, and the first retaining frame 211 can control the relative position between the rolling elements in the first bearing 210, thereby improving the working stability of the first bearing 210. The second bearing 310 includes a second retaining frame 311, and the second retaining frame 311 can control the relative position between the rolling elements in the second bearing 310, thereby improving the working stability of the second bearing 310. Along the direction of the rotation axis a0, the first retaining frame 211 protrudes from the end surface of the first eccentric portion 200 facing the middle portion 100, and the second retaining frame 311 protrudes from the end surface of the second eccentric portion 300 facing the middle portion 100. The first bearing 210 is abutted against one end surface of the first gasket 400 through the first retaining frame 211, and the second bearing 310 is abutted against the other end surface of the first gasket 400 through the second retaining frame 311.

[0046] The first gasket 400 has been subjected to surface smoothing treatment before assembly, and has good roughness. The first retainer 211 and the second retainer 311 are provided to make the first bearing 210 and the second bearing 310 respectively abut against the two ends of the first gasket 400; since the first gasket 400 has good roughness, the wear of the first bearing 210 and the second bearing 310 can be effectively reduced. At the same time, when the crankshaft assembly is in operation, the first gasket 400 rotates relative to the positioning section 130, reducing the relative sliding between the first bearing 210, the second bearing 310 and the first gasket 400, and reducing the friction of the first bearing 210 and the second bearing 310. In addition, the positioning section 130 positions the first gasket 400 along the radial direction of the first gasket 400, and the first bearing 210 and the second bearing 310 cooperate to position the first gasket 400 from both sides of the first gasket 400 along the axial direction of the first gasket 400, completing the positioning and installation of the first gasket 400, which can effectively improve the installation stability of the first gasket 400.

[0047] Reference Figure 2 and Figure 3As shown, it can be understood that the crankshaft assembly also includes a first support portion 500 and a second support portion 600 coaxially arranged with the positioning section 130, as well as a second gasket 700, a third gasket 800, a third bearing 510 and a fourth bearing 610, the first support portion 500 is connected to the side of the first eccentric portion 200 away from the first processing section 110, the second support portion 600 is connected to the side of the second eccentric portion 300 away from the second processing section 120, the third bearing 510 is installed on the first support portion 500, and the fourth bearing 610 is installed In the second support portion 600, the second gasket 700 is mounted on the first support portion 500 and is located between the third bearing 510 and the first bearing 210, and the two ends of the second gasket 700 respectively abut the end surfaces of the third bearing 510 and the first eccentric portion 200 that are away from the middle portion 100. The third gasket 800 is mounted on the second support portion 600 and is located between the fourth bearing 610 and the second bearing 310, and the two ends of the third gasket 800 respectively abut the end surfaces of the fourth bearing 610 and the second eccentric portion 300 that are away from the middle portion 100.

[0048] The first support part 500 transmits the power of the crankshaft assembly to the output shaft (not shown in the figure) through the third bearing 510, and the second support part 600 transmits the power of the crankshaft assembly to the support flange (not shown in the figure) through the fourth bearing 610. The first support part 500, the second support part 600, the third bearing 510 and the fourth bearing 610 cooperate to complete the power output of the RV reducer. By setting the second gasket 700, the third bearing 510 and the first bearing 210 are separated, so as to avoid mutual friction and collision between the third bearing 510 and the first bearing 210 during the operation of the RV reducer, thereby reducing the wear of the third bearing 510 and the first bearing 210; by setting the third gasket 800, the fourth bearing 610 and the second bearing 310 are separated, so as to avoid mutual friction and collision between the fourth bearing 610 and the second bearing 310 during the operation of the RV reducer, thereby reducing the wear of the fourth bearing 610 and the second bearing 310; the first gasket 400, the second gasket 700 and the third gasket 800 cooperate to separate the first bearing 210, the second bearing 310, the third bearing 510 and the fourth bearing 610 one by one, thereby effectively improving the independence of each bearing in the crankshaft assembly and improving the structural rationality of the crankshaft assembly.

[0049] Reference Figure 1 and Figure 3As shown, it can be understood that, projected along the direction of the rotation axis a0, the projection of the first bottom wall of the first eccentric groove 101 and the projection of the part of the peripheral wall of the middle part 100 connected to the first bottom wall form a closed first contour line 1012, and the first contour line 1012 is arranged around the rotation axis a0. Since the first eccentric part 200 is eccentrically arranged, this will cause the first eccentric part 200 to form a larger first crescent body 220 on the side of the rotation axis a0 close to the first central axis a1, and the first crescent body 220 on the side of the rotation axis away from the first central axis a1. A second crescent body 230 with a smaller volume is formed on one side, the first crescent body 220 and the second crescent form an integrally formed first eccentric portion 200, and the first eccentric groove 101 is milled out on the peripheral wall of the first processing section 110 after the tool (not shown in the figure) processes the first eccentric portion 200. Therefore, the first eccentric groove 101 needs to be processed from the edge of the middle portion 100 on the side of the rotation axis a0 away from the first central axis a1 to avoid the first processing section 110 protruding radially from the second crescent body 230 along the positioning section 130, so as to ensure that the first processing section 110 is A processing section 110 is recessed radially inwardly along the positioning section 130 on one side of the second crescent 230. At this time, the first contour line 1012 is located within the projection of the first eccentric portion 200. The projection of the second bottom wall of the second eccentric groove 102 and the projection of the part of the peripheral wall connected to the middle part 100 of the second bottom wall form a closed second contour line 1022. The second contour line 1022 is arranged around the rotation axis a0. Since the second eccentric portion 300 also forms a third crescent with a larger volume on the side of the rotation axis a0 close to the second central axis a2, 320, a smaller fourth crescent 330 is formed on the side of the rotation axis away from the second center axis a2, and the second eccentric groove 102 needs to be processed starting from the edge of the middle portion 100 on the side of the rotation axis a0 away from the second center axis a2 to avoid the second processing section 120 protruding radially out of the fourth crescent 330 along the positioning section 130, and ensure that the second processing section 120 is recessed radially inward along the positioning section 130 on one side of the fourth crescent 330. At this time, the second contour line 1022 is located within the projection of the second eccentric portion 300.

[0050] The outer diameter of the first eccentric portion 200 is g1, and the outer diameter of the second eccentric portion 300 is g2, which satisfies: (1 / 2)*g1+(1 / 2)*g2-b1-b2<e<(1 / 2)*g1+b1+b2+(1 / 2)*g2. Wherein, (1 / 2)*g1-b1+(1 / 2)*g2-b2 is the maximum distance between the second crescent 230 and the fourth crescent 330, and (1 / 2)*g1+b1+b2+(1 / 2)*g2 is the maximum distance between the first crescent 220 and the third crescent 320. The outer diameter e of the positioning segment 130 is limited to between (1 / 2)*g1+(1 / 2)*g2-b1-b2 and (1 / 2)*g1+b1+b2+(1 / 2)*g2, that is, along the radial direction of the positioning segment 130, the peripheral wall of the positioning segment 130 is limited between the peripheral wall of the first eccentric portion 200 and the peripheral wall of the second eccentric portion 300. On the one hand, it can avoid that the outer diameter of the positioning segment 130 is too short, which cannot effectively position and install. On the other hand, the outer diameter e of the positioning section 130 is reasonably limited and the first eccentric groove 101 and the second eccentric groove 102 are set. The first eccentric groove 101 can avoid the first bearing 210 at the second crescent 230, and the second eccentric groove 102 can avoid the second bearing 310 at the fourth crescent 330, thereby avoiding the circumferential wall of the positioning section 130 protruding from the first crescent 220 and / or the third crescent 320 along the radial direction of the positioning section 130, resulting in the end face of the middle part 100 interfering with the first bearing 210, and / or the movement of the second bearing 310, thereby ensuring the stable rotation of the first bearing 210 and the second bearing 310. At the same time, in addition to playing a avoidance role when the crank shaft assembly is working, the first eccentric groove 101 and the second eccentric groove 102 can also play a avoidance role when the crank shaft assembly is assembled, thereby preventing the middle part 100 from blocking the assembly of the first bearing 210 and the second bearing 310, facilitating the positioning and installation of the first bearing 210 and the second bearing 310, and effectively improving the structural rationality of the middle part 100.

[0051] In addition, the first eccentric groove 101 and the second eccentric groove 102 do not need to cooperate with other components, and the precision requirements of the first eccentric groove 101 and the second eccentric groove 102 are relatively low, which can effectively reduce the processing cost of the crank shaft assembly; and the first eccentric groove 101 and the second eccentric groove 102 can also play a role in oil storage, providing sufficient lubrication for the crank shaft assembly during operation.

[0052] It should be added that the outer diameter e of the positioning section 130 is mainly related to the inner diameter of the first gasket 400. The larger the inner diameter of the first gasket 400, the larger the outer diameter e of the positioning section 130. The smaller the inner diameter of the first gasket 400, the smaller the outer diameter e of the positioning section 130. The outer diameter e of the positioning section 130 is not specifically limited here. It is sufficient as long as the first gasket 400 can be accurately positioned along the radial direction of the positioning section 130.

[0053] Reference Figure 2 and Figure 4 As shown, it can be understood that the distance between the end face of the first eccentric portion 200 away from the middle portion 100 and the end face of the second eccentric portion 300 away from the middle portion 100 is j1, that is, the distance between the end faces on both sides of the first eccentric portion 200 and the second eccentric portion 300 opposite to each other is j1, and the maximum distance between the first bearing 210 and the second bearing 310 is j2, that is, the installation dimension of the first bearing 210 and the second bearing 310 is j2, satisfying: j1>j2. The distance j1 between the opposite side end faces of the first eccentric portion 200 and the second eccentric portion 300 is greater than the installation dimension j2 of the first bearing 210 and the second bearing 310, that is, along the radial direction of the first eccentric portion 200, the end face of the first eccentric portion 200 away from the middle portion 100 protrudes from the end face of the first bearing 210 away from the second bearing 310, and the end face of the second eccentric portion 300 away from the middle portion 100 protrudes from the end face of the second bearing 310 away from the first bearing 210. On the one hand, when the crankshaft assembly is assembled, the second gasket 700, the third gasket 800 and other components can be axially positioned by the opposite side end faces of the first eccentric portion 200 and the second eccentric portion 300, which effectively improves the assembly convenience and assembly precision of the crankshaft assembly; on the other hand, it is ensured that a certain gap is reserved between the first bearing 210 and the second gasket 700, and a certain gap is reserved between the second bearing 310 and the third gasket 800, so as to facilitate the free rotation of the first bearing 210 and the second bearing 310 and improve the smoothness of the operation of the crankshaft assembly.

[0054] It should be noted that the third bearing 510 and the fourth bearing 610 are usually set as needle bearings, thereby directly eliminating the need to consider the axial size matching requirements when selecting tapered roller bearings due to the need to axially preload the tapered roller bearings. At the same time, after the third bearing 510 and the end face of the first eccentric part 200 cooperate to axially position the second gasket 700, other components of the RV deceleration, such as the first main bearing between the crankshaft assembly and the output shaft (not shown in the figure), are axially positioned through the second gasket 700; after the fourth bearing 610 and the end face of the second eccentric part 300 cooperate to axially position the third gasket 800, other components of the RV deceleration, such as the second main bearing between the crankshaft assembly and the support flange (not shown in the figure), are axially positioned through the third gasket 800. The cooperation of the needle roller type third bearing 510, the needle roller type fourth bearing 610, the second gasket 700 and the third gasket 800 eliminates the processing accuracy requirements required for the end faces of the first eccentric part 200 and the second eccentric part 300 of other components of the RV reducer, greatly reduces the axial dimensional accuracy requirements of the first support part 500 and the second support part 600 and the axial installation dimensional accuracy requirements of the output shaft and the support flange, thereby reducing the processing difficulty and assembly difficulty of the crankshaft assembly.

[0055] Reference Figure 3 and Figure 4 As shown, it can be understood that the second gasket 700 and the first support part 500 are clearance-fitted so that the second gasket 700 can rotate relative to the first support part 500, and along the radial direction of the second gasket 700, the distance that the second gasket 700 exceeds the outer peripheral edge of the third bearing 510 is k1, satisfying: k1≥2mm; and / or, the third gasket 800 and the second support part 600 are clearance-fitted so that the third gasket 800 can rotate relative to the second support part 600, and along the radial direction of the third gasket 800, the distance that the third gasket 800 exceeds the outer peripheral edge of the fourth bearing 610 is k2, satisfying: k2≥2mm. The distance that the second gasket 700 exceeds the outer circumference of the third bearing 510 is limited to 2 mm or more, ensuring that the second gasket 700 has enough area on the outside of the part that abuts the third bearing 510 to contact and bear force with the first main bearing and other components; the distance that the third gasket 800 exceeds the outer circumference of the third bearing 510 is limited to 2 mm or more, ensuring that the third gasket 800 has enough area on the outside of the part that abuts the fourth bearing 610 to contact and bear force with the second main bearing and other components. Reasonably limiting the distance k1 that the second gasket 700 exceeds the outer circumference of the third bearing 510 and the distance k2 that the third gasket 800 exceeds the outer circumference of the fourth bearing 610 facilitates the assembly of the RV reducer, reasonably bears the stress of the main bearing and other components, and effectively improves the structural stability of the RV reducer.

[0056] Reference Figure 2 and Figure 4As shown, it can be understood that the distance between the end face of the first support portion 500 away from the first eccentric portion 200 and the end face of the second support portion 600 away from the second eccentric portion 300 is h1, that is, the distance between the end faces on both sides of the first support portion 500 and the second support portion 600 opposite to each other is h1, and the maximum distance between the third bearing 510 and the fourth bearing 610 is h2, that is, the installation dimension of the third bearing 510 and the fourth bearing 610 is h2, satisfying: h1>h2. The distance h1 between the opposite side end faces of the first support portion 500 and the second support portion 600 is greater than the installation dimension h2 of the third bearing 510 and the fourth bearing 610, that is, along the radial direction of the first support portion 500, the end face of the first support portion 500 away from the first eccentric portion 200 protrudes from the end face of the third bearing 510 away from the second gasket 700, and the end face of the second support portion 600 away from the second eccentric portion 300 protrudes from the end face of the fourth bearing 610 away from the third gasket 800. On the one hand, when the crankshaft assembly is assembled, other components of the RV reducer, such as the panel (not shown in the figure) on the support flange and other components can be axially positioned on the crankshaft assembly as a whole through the opposite side end faces of the first support portion 500 and the second support portion 600, further improving the assembly convenience and assembly precision of the crankshaft assembly; on the other hand, the axial space between the third bearing 510 and the fourth bearing 610 and the baffle or other gaskets (not shown in the figure) is not limited, ensuring the free rotation of the third bearing 510 and the fourth bearing 610, thereby improving the smoothness of the operation of the crankshaft assembly.

[0057] Reference Figure 3 and Figure 5 As shown, it can be understood that the first bottom wall is configured as a first arc surface 1011 whose rotation center is the first center axis a1, that is, the first bottom wall and the first eccentric portion 200 are coaxial, and the diameter of the first arc surface 1011 is f1, that is, the outer diameter of the first processing section 110 is f1, satisfying: f1<g1. Since the first eccentric groove 101 is formed by milling the peripheral wall of the first processing section 110 with the edge of the second crescent 230 as a reference after the first eccentric portion 200 is processed, the first bottom wall of the first eccentric groove 101 is configured as a first circular arc surface 1011 coaxial with the first eccentric portion 200, and the diameter f1 of the first circular arc surface 1011 is smaller than the outer diameter g1 of the first eccentric portion 200, that is, the tool processes the first processing section 110 radially inwardly along the first eccentric portion 200 to form the first eccentric groove 101, and the rotation center of the crankshaft assembly remains unchanged, which can facilitate continuous processing of the tool, effectively reduce the processing requirements of the crankshaft assembly, and improve the production efficiency of the crankshaft assembly.

[0058] Reference Figure 3 and Figure 6As shown, it can be understood that the second bottom wall is configured as a second arc surface 1021 with the rotation center being the second center axis a2, that is, the second bottom wall and the second eccentric portion 300 are coaxial, and the diameter of the second arc surface 1021 is f2, that is, the outer diameter of the second processing section 120 is f2, satisfying: f2<g2. Since the second eccentric groove 102 is formed by milling the peripheral wall of the second processing section 120 with the edge of the fourth crescent 330 as a reference after the second eccentric portion 300 is processed, the second bottom wall of the second eccentric groove 102 is configured as a second arc surface 1021 coaxial with the second eccentric portion 300, and the diameter f2 of the second arc surface 1021 is smaller than the outer diameter g2 of the second eccentric portion 300, that is, the tool processes the second processing section 120 radially inwardly along the second eccentric portion 300 to form the second eccentric groove 102, and the rotation center of the crankshaft assembly remains unchanged, which can facilitate continuous processing of the tool, further reduce the processing requirements of the crankshaft assembly, and improve the production efficiency of the crankshaft assembly.

[0059] It should be noted that the first arc surface 1011 and the peripheral wall of the first processing section 110 are usually smoothly transitioned, and the second arc surface 1021 and the peripheral wall of the second processing section 120 are also smoothly transitioned, that is, the first contour line 1012 and the first contour line 1012 are both smooth curves, which can avoid the formation of steps between the first bottom wall and the peripheral wall of the first processing section 110 or between the second bottom wall and the peripheral wall of the second processing section 120, which affects the tool retraction; it can also ensure that the appearance of the middle part 100 is natural and smooth, effectively improving the appearance of the middle part 100.

[0060] Reference Figure 1 and Figure 7 As shown, it can be understood that the thickness of the first gasket 400 is m, and the width of the middle part 100 is d, which satisfies: 1mm≤m<(2 / 3)d. The thickness m of the first gasket 400 is limited to more than 1mm to ensure that the first gasket 400 has sufficient strength to bear the impact of the first bearing 210 and the second bearing 310, effectively extending the service life of the first gasket 400; the thickness m of the first gasket 400 is limited to less than 2 / 3 times the width d of the middle part 100 to avoid the first gasket 400 occupying too much space outside the middle part 100, resulting in too small axial activity space of the first bearing 210 and the second bearing 310, and the first gasket 400 excessively squeezes the first bearing 210 and the second bearing 310. The friction of the first bearing 210 and the second bearing 310 is further reduced.

[0061] Reference Figure 7 and Figure 8As shown, it can be understood that since the volume of the second crescent 230 of the first eccentric portion 200 on the side of the rotation axis a0 away from the first central axis a1 is smaller, that is, the distance between the outer edge of the second crescent 230 and the rotation axis a0 is shorter, the first bearing 210 at the second crescent 230 will be closer to the rotation axis a0 than the first bearing 210 at other positions. At this time, the first gasket 400 protrudes radially from the first bearing 210 at the second crescent 230 along the positioning section 130. Specifically, along the radial direction of the first gasket 400, the distance that the first gasket 400 exceeds the outer peripheral edge of the first bearing 210 is n1, that is, the thickness of the portion of the first gasket 400 protruding from the first bearing 210 at the second crescent 230 is n1; similarly, the distance that the first gasket 400 exceeds the outer peripheral edge of the second bearing 310 is n2, that is, the thickness of the portion of the first gasket 400 protruding from the second bearing 310 at the fourth crescent 330 is n1; satisfying: n1≥0, n2≥0. The thickness n1 of the portion of the first gasket 400 protruding from the first bearing 210 and the thickness n2 of the portion of the first gasket 400 protruding from the second bearing 310 are limited to be greater than 0, ensuring that the first gasket 400 has sufficient area at the second crescent 230 to contact the first bearing 210 and sufficient area at the fourth crescent 330 to contact the second bearing 310, thereby optimizing the stress distribution of the crankshaft assembly and further improving the structural stability of the crankshaft assembly.

[0062] In addition, the first eccentric portion 200 and the second eccentric portion 300 are centrally symmetrical, that is, the first bearing 210 at the second crescent 230 and the second bearing 310 and the first gasket 400 at the fourth crescent 330 are centrally symmetrical. Therefore, the thickness n1 of the portion protruding from the first bearing 210 and the thickness n2 of the portion protruding from the second bearing 310 of the first gasket 400 are generally equal, that is, the first gasket 400 and the positioning section 130 are coaxial to ensure the positioning accuracy of the first gasket 400.

[0063] Continue to refer to Figure 7 and Figure 8As shown, it can be understood that the width of the middle portion 100 is d, the width of the first eccentric groove 101 is c1, that is, the width of the first processing section 110 is c1, and the width of the second eccentric groove 102 is c2, that is, the width of the second processing section 120 is c2, which satisfies: 2*c1<d≤4*c1, 2*c2<d≤4*c2. Adding the above formulas and simplifying them, the following formula can be obtained: 0<d-(c1+c2)≤(c1+c2), where d-(c1+c2) is the length of the positioning section 130, and the length of the positioning section 130 is limited to above 0, that is, along the radial direction of the middle portion 100, the thickness of the positioning section 130 is not 0, that is, along the radial direction of the middle portion 100, the first eccentric groove 101 and the second eccentric groove 102 are not connected, thereby avoiding the presence of a gap in the peripheral wall of the positioning section 130, resulting in the positioning section 130 lacking the first gasket 40 at the gap. 0, thereby avoiding the radial positioning of the first gasket 400 when the crankshaft assembly rotates at high speed due to the lack of radial positioning of the first gasket 400, and the radial shaking of the first gasket 400, and effectively improving the working stability of the first gasket 400; the length of the positioning section 130 is limited to less than the total length of the first processing section 110 and the second processing section 120, to avoid the total length d of the middle section being too long, the distance between adjacent cycloid wheels being too large, resulting in increased torque at both ends of the middle section 100, easy damage to the middle section 100, unstable power transmission, and other problems. By reasonably limiting the width of the middle section 100 to d, while improving the working stability of the first gasket 400, the structural layout of the crankshaft assembly is optimized, the structural tightness of the crankshaft assembly is further improved, and the processing cost of the high crankshaft assembly can be reduced.

[0064] Reference Figure 3 , Figure 7 and Figure 8 As shown, it can be understood that the width c1 of the first eccentric groove 101 and the width c2 of the second eccentric groove 102 are equal. The first bottom wall is the first arc surface 1011 set around the first central axis a1, and the second bottom wall is the second arc surface 1021 set around the second central axis a2. The first central axis a1 and the second central axis a2 are symmetrical about the rotation axis a0, and the first arc surface 1011 and the second arc surface 1021 are symmetrical along the projection center of the rotation axis a0. The width c1 of the first eccentric groove 101 and the width c2 of the second eccentric groove 102 are set to be equal, that is, the first eccentric groove 101 and the second eccentric groove 102 are set to be symmetrical, which can effectively improve the symmetry of the middle part 100, further optimize the structural layout, and facilitate the production and processing of the crankshaft assembly.

[0065] The RV reducer of the second embodiment of the present invention includes the crankshaft assembly of the first embodiment. The crankshaft assembly reduces the wear of the first bearing 210 and the second bearing 310 by setting the middle part 100 and installing the first gasket 400 on the middle part 100, prolongs the service life of the crankshaft assembly, and ensures the transmission accuracy of the crankshaft assembly; by reasonably limiting the size of the middle part 100, coordinating the first eccentric groove 101 that avoids the first bearing 210 and the second eccentric groove 102 that avoids the second bearing 310, while facilitating the positioning and installation of the first gasket 400, the first bearing 210 and the second bearing 310 are ensured to move stably, effectively improving the structural rationality of the middle part 100.

[0066] The industrial robot of the third embodiment of the present invention includes the RV reducer of the second embodiment.

[0067] Since the industrial robot adopts all the technical solutions of the RV reducer of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

[0068] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A crankshaft assembly, characterized in that: include: A middle part, with a first eccentric groove and a second eccentric groove respectively provided at two ends along the rotation axis, and the outer diameter of the middle part is e; A first eccentric portion, connected to one end of the middle portion provided with the first eccentric groove, and eccentrically arranged with the middle portion, wherein a first central axis of the first eccentric portion is parallel to the rotation axis and the offset is b1, and an outer diameter of the first eccentric portion is g1; A second eccentric portion, connected to one end of the middle portion provided with a second eccentric groove, and eccentrically arranged with respect to the middle portion, a second central axis of the second eccentric portion is parallel to the rotation axis of the middle portion and the offset is b2, and an outer diameter of the second eccentric portion is g2; A first gasket, mounted on the middle portion and capable of rotating relative to the middle portion; a first bearing, mounted on the first eccentric portion and abutting against the first gasket; a second bearing, mounted on the second eccentric portion and abutting against the first gasket; Wherein, projected along the direction of the rotation axis, the projection of the first bottom wall of the first eccentric groove and the projection of part of the peripheral wall of the middle portion form a first contour line around the rotation axis, and the first contour line is located within the projection of the first eccentric portion, and the projection of the second bottom wall of the second eccentric groove and the projection of part of the peripheral wall of the middle portion form a second contour line around the rotation axis, and the second contour line is located within the projection of the second eccentric portion; And it satisfies: (1 / 2)*g1+(1 / 2)*g2-b1-b2<e<(1 / 2)*g1+b1+b2+(1 / 2)*g2.

2. The crankshaft assembly according to claim 1, characterized in that: The first bearing includes a first retaining frame, and the second bearing includes a second retaining frame. Along the direction of the rotation axis, the first retaining frame protrudes from the end surface of the first eccentric portion toward the middle portion, and the second retaining frame protrudes from the end surface of the second eccentric portion toward the middle portion. Both ends of the first gasket respectively abut the first retaining frame and the second retaining frame.

3. The crankshaft assembly according to claim 1 or 2, characterized in that: The thickness of the first gasket is m, and the width of the middle portion is d, satisfying: 1mm≤m<(2 / 3)d.

4. The crankshaft assembly according to claim 1, characterized in that: Along the radial direction of the first gasket, the distance that the first gasket exceeds the outer circumference of the first bearing is n1, and the distance that the first gasket exceeds the outer circumference of the second bearing is n2, satisfying: n1≥0, n2≥0.

5. The crankshaft assembly according to claim 1, characterized in that: The width of the middle portion is d, the width of the first eccentric groove is c1, and the width of the second eccentric groove is c2, satisfying: 2*c1<d≤4*c1, 2*c2<d≤4*c2.

6. The crankshaft assembly according to claim 5, characterized in that: The width c1 of the first eccentric groove is equal to the width c2 of the second eccentric groove.

7. The crankshaft assembly according to claim 5, characterized in that: The first bottom wall is configured as a first arc surface whose rotation center is the first central axis. The diameter of the first arc surface is f1, and the following satisfies: f1<g1.

8. The crankshaft assembly according to claim 5, characterized in that: The second bottom wall is configured as a second arc surface whose rotation center is the second central axis, and the diameter of the second arc surface is f2, satisfying: f2<g2.

9. The crankshaft assembly according to claim 1, characterized in that: The crankshaft assembly also includes a first support portion and a second support portion coaxially arranged with the middle portion, as well as a second gasket, a third gasket, a third bearing and a fourth bearing, the first support portion is connected to the first eccentric portion, the second support portion is connected to the second eccentric portion, the third bearing is installed on the first support portion, the fourth bearing is installed on the second support portion, the second gasket is sleeved on the first support portion and its two ends respectively abut against the end surface of the third bearing and the first eccentric portion, the third gasket is sleeved on the second support portion and its two ends respectively abut against the end surface of the fourth bearing and the second eccentric portion.

10. The crankshaft assembly according to claim 9, characterized in that: The distance between the end surface of the first support portion away from the first eccentric portion and the end surface of the second support portion away from the second eccentric portion is h1, and the maximum distance between the third bearing and the fourth bearing is h2, satisfying: h1>h2.

11. The crankshaft assembly according to claim 9, characterized in that: The distance between the end surface of the first eccentric portion away from the middle portion and the end surface of the second eccentric portion away from the middle portion is j1, and the maximum distance between the first bearing and the second bearing is j2, satisfying: j1>j2.

12. The crankshaft assembly according to claim 9, characterized in that: The second gasket is rotatable relative to the first support portion. In the radial direction of the second gasket, the distance of the second gasket beyond the outer peripheral edge of the third bearing is k1, and the following conditions are satisfied: k1 ≥ 2 mm; and / or, The third gasket is rotatable relative to the second supporting portion. Along the radial direction of the third gasket, the distance that the third gasket exceeds the outer circumference of the fourth bearing is k2, and the following condition is satisfied: k2≥2mm. 13.RV reducer, characterized by: A crankshaft assembly comprising any one of claims 1 to 12.

14. An industrial robot, characterized in that: Including the RV reducer as described in claim 13.

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