Bilinear matching ball-and-socket joint
By introducing a bilinear mating structure into the ball and socket joints, the problem of difficult to take into account both machining accuracy and lubrication reliability in the prior art is solved, and the ball and socket joint design for high-precision and low-lubricating media is realized, which improves the motion performance of the robot joint.
Patent Information
- Application Number
- CN202422463718.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2034-10-11
AI Technical Summary
The machining accuracy and lubrication reliability of the existing ball and socket joint structures are difficult to take into account, resulting in limited coordination accuracy and movement effect.
A bilinear matching ball and socket joint structure is adopted, and the first and second linear parts are arranged in the ball and socket cavity, and the outer spherical surface of the ball head is linearly matched to reduce the use of lubricating media, reduce processing difficulty and improve coordination accuracy.
While ensuring processing accuracy, it reduces the limitation of lubrication reliability on the movement effect, and improves the coordination accuracy and movement performance of the ball and socket joints.
Smart Images
Figure CN223049231U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of robot motion joints, and particularly relates to a bilinear matching ball socket joint. Background Art
[0002] There are a large number of joint structures in the body structure of a robot. As the core moving components of the robot, with the continuous improvement of the requirements for the efficiency of robot products, the requirements for the matching accuracy of its joint structures are also continuously increasing.
[0003] The main factors affecting the matching accuracy of joint structures are: machining accuracy and lubrication reliability. The ball head and ball bowl of the existing ball socket joint structure are mostly in global surface contact, which poses extremely high requirements for machining accuracy. Any machining error or deformation at any contact position will affect the matching accuracy of the ball socket joint structure. Lubrication reliability is related to machining accuracy. The existing ball socket joint structures generally still require lubrication. Some ball socket joints with global surface contact need to be filled with lubricating media on the mating surfaces due to their large self-weight and insufficient surface finish, resulting in the actual motion effect being limited by lubrication reliability. Therefore, a ball socket joint with a new matching structure is needed. Summary of the Utility Model
[0004] In order to solve the above problems existing in the prior art, the utility model provides a bilinear matching ball socket joint. The technical problems to be solved by the utility model are realized through the following technical solutions:
[0005] The utility model provides a bilinear matching ball socket joint, comprising: a ball bowl, which is provided with a ball socket cavity inside, and a first linear part and a second linear part are arranged on the inner surface of the ball socket cavity, and the first linear part is located on the second linear part; the first linear part and the second linear part are coaxially arranged and both protrude inward from the inner surface of the ball socket cavity, both the first linear part and the second linear part are annular, and the radius of the first linear part is greater than the radius of the second linear part; a ball head, at least part of which is located inside the ball socket cavity, and the ball head is rotatably connected to the ball bowl; the ball head has an outer spherical surface, and the outer spherical surface is linearly matched with the first linear part and the second linear part respectively; a connecting rod, connecting the ball head.
[0006] In an embodiment of the utility model, the range of the distance l between the first linear part and the second linear part is: 1 / 6r ≤ l ≤ 5 / 6r; wherein, r is the radius of the outer spherical surface of the ball head.
[0007] In an embodiment of the utility model, the range of the radius r2 of the second linear part is: 1 / 6r1 ≤ r2 ≤ 5 / 6r1; wherein, r1 is the radius of the first linear part.
[0008] In an embodiment of the utility model, the angle α between the connection line of the coplanar projections of the first linear part and the second linear part in the horizontal direction and the horizontal plane is 45°.
[0009] In an embodiment of the present utility model, the depth h of the ball socket cavity is greater than the radius r of the outer spherical surface of the ball head.
[0010] In an embodiment of the present utility model, the bottom of the ball bowl is connected to a first connecting portion. A first connecting hole is provided on the first connecting portion along the vertical direction, and the central axis of the first connecting hole coincides with the central axis of the first linear portion or the second linear portion.
[0011] In an embodiment of the present utility model, the ball head is provided with a second connecting hole and is connected to a connecting rod through the second connecting hole. The extension line of the central axis of the connecting rod passes through the center of the ball of the ball head.
[0012] In an embodiment of the present utility model, internal threads are provided in the second connecting hole, external threads are provided at at least one end of the connecting rod, and the internal threads cooperate with the external threads.
[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0014] For the double-linear matching ball socket joint of the present utility model, a first linear portion and a second linear portion are provided in the ball socket cavity of the ball bowl. The outer spherical surface of the ball head is linearly matched with the first linear portion and the second linear portion, which reduces the processing difficulty while improving the matching accuracy. Using double-linear matching can also reduce or eliminate the use of lubricating media, which reduces the limitation of lubrication reliability on the movement effect of the ball socket joint while ensuring the processing accuracy.
[0015] The above description is only an overview of the technical solution of the present utility model. In order to understand the technical means of the present utility model more clearly, it can be implemented according to the content of the description. In order to make the above and other purposes, features and advantages of the present utility model more obvious and understandable, the following preferred embodiments are specifically given and described in detail in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a schematic structural diagram of a double-linear matching ball socket joint provided by an embodiment of the present utility model;
[0017] Figure 2 is a cross-sectional structural view of a double-linear matching ball socket joint provided by an embodiment of the present utility model.
[0018] Reference numerals: 1 - ball bowl; 11 - ball socket cavity; 111 - first linear portion; 112 - second linear portion; 12 - first connecting portion; 121 - first connecting hole; 2 - ball head; 21 - second connecting hole; 3 - connecting rod. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] To further elaborate on the technical means and effects adopted by the present utility model to achieve the intended utility model purpose, the following provides a detailed description of a bilinear mating ball and socket joint proposed according to the present utility model in conjunction with the accompanying drawings and specific embodiments.
[0020] The foregoing and other technical contents, features, and effects of the present utility model can be clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding of the technical means and effects adopted by the present utility model to achieve the intended purpose can be obtained. However, the accompanying drawings are only for reference and illustration, and are not used to limit the technical solution of the present utility model.
[0021] Embodiment 1
[0022] As Figure 1 and Figure 2 shown, the present utility model provides a bilinear mating ball and socket joint, including: a ball bowl 1, a ball head 2, and a connecting rod 3.
[0023] In this embodiment, the ball bowl 1 is provided with a ball socket cavity 11 inside. On the inner surface of the ball socket cavity 11, a first linear portion 111 and a second linear portion 112 are provided. The first linear portion 111 is located on the second linear portion 112. The first linear portion 111 and the second linear portion 112 are coaxially arranged and both protrude inward from the inner surface of the ball socket cavity 11. Both the first linear portion 111 and the second linear portion 112 are annular, and the radius of the first linear portion 111 is greater than the radius of the second linear portion 112. The ball head 2 is at least partially located inside the ball socket cavity 11, and the ball head 2 is rotatably connected to the ball bowl 1. The ball head 2 has an outer spherical surface, and the outer spherical surface is linearly mated with the first linear portion 111 and the second linear portion 112 respectively. The connecting rod 3 is connected to the ball head 2.
[0024] Optionally, the ball socket cavity 11 can be of a spherical or hemispherical structure. Correspondingly, the inner surface of the ball socket cavity 11 excluding the first linear portion 111 and the second linear portion 112 can also be a spherical surface.
[0025] The working principle of the bilinear mating ball and socket joint of the present utility model is as follows: The annular first linear portion 111 and the second linear portion 112 are arranged at intervals inside the ball socket cavity 11. When the ball head 2 rotates, the outer spherical surface is always linearly mated with the first linear portion 111 and the second linear portion 112, and the ball head 2 is at least partially located inside the ball socket cavity 11 of the ball bowl 1.
[0026] In an optional embodiment, the range of the distance l between the first linear portion 111 and the second linear portion 112 is:
[0027] 1 / 6r ≤ l ≤ 5 / 6r (1);
[0028] where r is the radius of the outer spherical surface of the ball head 2.
[0029] In an alternative embodiment, the radius r1 of the first linear portion 111 matches the radius r of the outer spherical surface of the ball head 2, and a clearance fit may be provided therebetween.
[0030] Furthermore, the range of the radius r2 of the second linear portion 112 is:
[0031] 1 / 6r1 ≤ r2 ≤ 5 / 6r1 (2);
[0032] wherein, r1 is the radius of the first linear portion 111.
[0033] In an alternative embodiment, the angle α between the connecting line of the coplanar projections of the first linear portion 111 and the second linear portion 112 in the horizontal direction and the horizontal plane is 45°.
[0034] It should be noted that the connecting line of the projections of the first linear portion 111 and the second linear portion 112 is a virtual connecting line, that is, there is no direct structural connection or contact between the first linear portion 111 and the second linear portion 112 within the ball socket cavity 11. And to avoid interference, the connection portion between the first linear portion 111 and the second linear portion 112 is recessed outward, and the radius at the maximum recess position of the connection portion is greater than the radius r1 of the first linear portion 111.
[0035] In an alternative embodiment, the depth h of the ball socket cavity 11 is greater than the radius r of the outer spherical surface of the ball head 2, so as to ensure that at least a part of the outer spherical surface of the ball head 2 is located within the ball socket cavity 11, and after linear cooperation with the first linear portion 111 and the second linear portion 112 respectively, it can rotate freely and will not disengage during the free rotation process.
[0036] It is worth noting that the first linear portion 111 is used to limit the ball head 2 to ensure that the ball head 2 does not disengage from the cooperation, and is also used to assist in supporting the ball head 2; the second linear portion 112 is used to support the ball head 2 and is also used to assist in limiting.
[0037] In an alternative embodiment, the bottom of the ball bowl 1 is connected to the first connecting portion 12. A first connecting hole 121 is provided on the first connecting portion 12 in the vertical direction, and the central axis of the first connecting hole 121 coincides with the central axis of the first linear portion 111 or the second linear portion 112. Similar to the ball head 2, the ball bowl 1 can also be connected to its link structure through the first connecting hole 121.
[0038] Optionally, internal threads may be provided in the first connecting hole 121.
[0039] In an alternative embodiment, the ball head 2 is provided with a second connection hole 21 and is connected to the connecting rod 3 through the second connection hole 21. The extension line of the central axis of the connecting rod 3 passes through the center of the ball of the ball head 2, and the position of the connecting rod 3 is set opposite to the center of the ball head 2, which is beneficial to controlling the rotation of the ball head 2 in the ball socket 1 through the connecting rod 3 and preventing control deviation caused by eccentricity.
[0040] In an alternative embodiment, internal threads are provided in the second connection hole 21, and external threads are provided at at least one end of the connecting rod 3, and the internal threads are matched with the external threads. In addition, to improve the reliability of the threaded connection, thread glue can be first applied to the internal threads and then connected to the external threads of the connecting rod 3. After the thread glue is cured, the ball head 2 and the connecting rod 3 are connected as a whole.
[0041] Optionally, the ball bowl 1 and the ball head 2 can be made of a hard material with a relatively high hardness. Good surface finish can be achieved through processing techniques such as grinding, and lubricating media can be used less or not at all. Although its relatively high hardness also increases the processing difficulty, since the outer spherical surface of the bilinear mating ball socket joint in this embodiment only linearly mates with the first linear part 111 and the second linear part 112, the requirement for machining accuracy is lower than that of global spherical surface contact, but the mating accuracy is improved. Exemplarily, the ball bowl 1 can be made of ceramic materials, including alumina, zirconia, silicon nitride, boron nitride or titanium nitride. Similarly, the ball head 2 can also be made of ceramic materials.
[0042] It should be noted that in this embodiment, the materials used for the ball bowl 1 and the ball head 2 are not limited. In addition to the above-mentioned ceramic materials, similar hard materials can also be used. At the same time, lubricating media can also be used between the ball bowl 1 and the ball head 2, and the type of lubricating media used is not limited either. In addition, wear-resistant layers made of hard materials can be provided on the inner surface of the ball socket cavity 11 and the outer spherical surface of the ball head 2, and the thickness of the wear-resistant layer can be 0.1 mm to 2 mm, such as: 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm.
[0043] In the bilinear mating ball socket joint of the present invention, a first linear part and a second linear part are provided in the ball socket cavity of the ball bowl, and the outer spherical surface of the ball head linearly mates with the first linear part and the second linear part, which reduces the processing difficulty while improving the mating accuracy. Using bilinear mating can also use less or no lubricating media, which reduces the limitation of lubrication reliability on the movement effect of the ball socket joint while ensuring the machining accuracy.
[0044] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant is intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed. Without more limitations, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or device comprising the element. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 construed as a limitation of the present invention.
[0045] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.
Claims
1. A bilinear ball-and-socket joint, characterized in that: include: A ball bowl (1) is provided with a socket cavity (11) therein, wherein a first linear portion (111) and a second linear portion (112) are provided on the inner surface of the socket cavity (11), wherein the first linear portion (111) is located on the second linear portion (112); the first linear portion (111) and the second linear portion (112) are coaxially arranged and both protrude inwardly from the inner surface of the socket cavity (11); the first linear portion (111) and the second linear portion (112) are both annular, and the radius of the first linear portion (111) is greater than the radius of the second linear portion (112); A ball head (2) is at least partially located in the ball socket cavity (11), and the ball head (2) is rotatably connected to the ball bowl (1); the ball head (2) has an outer spherical surface, and the outer spherical surface is linearly matched with the first linear portion (111) and the second linear portion (112) respectively; A connecting rod (3) is connected to the ball head (2).
2. The bilinear ball-and-socket joint according to claim 1, characterized in that: The range of the distance l between the first linear portion (111) and the second linear portion (112) is: 1 / 6r≤l≤5 / 6r; Wherein, r is the radius of the outer spherical surface of the ball head (2).
3. The bilinear ball-and-socket joint according to claim 1, characterized in that: The radius r2 of the second linear portion (112) is in the range of: 1 / 6r1≤r2≤5 / 6r1; Wherein, r1 is the radius of the first linear portion (111).
4. The bilinear ball-and-socket joint according to claim 1, characterized in that: The angle α between a line connecting coplanar projections of the first linear portion (111) and the second linear portion (112) along the horizontal direction and a horizontal plane is 45°.
5. The bilinear ball-and-socket joint according to claim 1, characterized in that: The depth h of the ball socket cavity (11) is greater than the radius r of the outer spherical surface of the ball head (2).
6. The bilinear ball-and-socket joint according to claim 1, characterized in that: The bottom of the ball bowl (1) is connected to a first connecting portion (12), a first connecting hole (121) is provided on the first connecting portion (12) in a vertical direction, and a central axis of the first connecting hole (121) coincides with a central axis of the first linear portion (111) or the second linear portion (112).
7. The bilinear ball-and-socket joint according to claim 1, characterized in that: The ball head (2) is provided with a second connecting hole (21), and is connected to the connecting rod (3) via the second connecting hole (21); an extension line of the central axis of the connecting rod (3) passes through the center of the ball head (2).
8. The bilinear ball-and-socket joint according to claim 7, characterized in that: The second connecting hole (21) is provided with an internal thread, and at least one end of the connecting rod (3) is provided with an external thread, and the internal thread cooperates with the external thread.