Planetary roller screw pair

Abstract

The utility model discloses a planetary roller lead screw pair, which belongs to the technical field of transmission devices, and adopts the technical scheme that the planetary roller lead screw pair comprises a sleeve, a roller mechanism is arranged in the sleeve, a lead screw is arranged in the roller mechanism, the roller mechanism comprises internal thread rings which are respectively in threaded connection with the front side and the rear side in the sleeve, and the lead screw is arranged in the sleeve. The roller mechanism is arranged, the inner threaded ring is in threaded connection with the sleeve and is connected with the fixed shaft and the first roller, stable radial and circumferential support is provided for the first roller, the auxiliary rotating structure is matched with the first roller, and the first roller can be supported in the radial direction and the circumferential direction, so that the stability of the roller mechanism is improved, and the service life of the roller mechanism is prolonged. According to the planetary roller lead screw pair, constraint movement on the lead screw is increased, it is ensured that the first roller and the auxiliary rotating structure can stably move around the lead screw under the complex working conditions of high speed and heavy load or frequent starting and stopping, and the working reliability and the bearing capacity of the planetary roller lead screw pair are remarkably improved.

Description

Technical Field

[0001] The utility model relates to the technical field of transmission devices, and particularly relates to a planetary roller screw pair. Background Art

[0002] A planetary roller screw pair is a mechanical transmission device that can convert rotational motion and linear motion into each other. The rolling elements of the planetary roller screw pair are planetary rollers. Compared with the commonly used ball screw pair, the planetary roller screw pair has the transmission characteristics of multiple points, multiple pairs, and multiple bodies, which determines its advantages of large thrust, high precision, high rigidity, long service life, good dynamic performance, convenient installation and maintenance, etc.

[0003] Due to the helix angle, there is an inclined moment on the roller. If the circumferential direction is not fixed, the roller will slide or even spin under the action of the inclined moment, which will seriously affect the working reliability and load-bearing capacity of the planetary roller screw. And due to the complex structure of the planetary roller screw, it is difficult to install and disassemble it. Moreover, during long-term high-speed movement between the screw rod, the roller, and the nut, the screw rod, the roller, and the nut are easily worn, which will reduce the service life and transmission efficiency of the planetary roller screw;

[0004] The existing patent (publication number: CN210531536U) discloses a planetary roller screw pair. In this utility model, the outer end face of the retaining ring is sleeved inside the internal gear ring, and the end teeth are meshed with the internal gear ring to ensure the coordinated operation of the nut and the roller, reduce the sliding between the roller and the screw rod and the nut, improve the working reliability and load-bearing capacity of the planetary roller screw pair, and the shaft collar is snap-fitted in the first mounting hole, and the installation and disassembly of the shaft collar are simple and convenient.

[0005] In view of the above problems, the existing patent gives a solution. However, in complex working conditions, the inclined moment generated by the helix angle of the roller in the existing planetary roller screw pair may still cause it to slide or spin. For example, in application scenarios such as high-speed heavy load or frequent start-stop, it is difficult to completely suppress the unstable movement of the roller only by the existing fixing method, which will further affect the working reliability and load-bearing capacity of the planetary roller screw pair.

[0006] Therefore, a planetary roller screw pair is proposed. Summary of the Utility Model

[0007] The purpose of the utility model is to provide a planetary roller screw pair, which can solve the problem that in complex working conditions of the existing planetary roller screw pair, the inclined moment generated by the helix angle of the roller may still cause it to slide or spin. For example, in application scenarios such as high-speed heavy load or frequent start-stop, it is difficult to completely suppress the unstable movement of the roller only by the existing fixing method, which will further affect the working reliability and load-bearing capacity of the planetary roller screw pair.

[0008] To achieve the above object, the present utility model provides the following technical solution: A planetary roller screw pair, comprising a sleeve, wherein a roller mechanism is arranged inside the sleeve, and a lead screw is arranged inside the roller mechanism.

[0009] The roller mechanism includes internal thread rings respectively threadedly connected to the front side and the rear side inside the sleeve. A fixed shaft is rotatably connected to the inner side of the internal thread ring. A first roller is fixedly connected to the outer side of the fixed shaft. The first roller is located on the outer side of the lead screw. An auxiliary rotation structure is arranged inside the internal thread ring, and the auxiliary rotation structure is located on the outer side of the lead screw.

[0010] Preferably, the auxiliary rotation structure includes positioning rods arranged at the triangle inside the internal thread ring, and the outer sides of the positioning rods penetrate through the inside of the internal thread ring.

[0011] Preferably, a second roller is rotatably connected to the outer side of the positioning rod. The second roller is located inside the adjacent first roller, and the second roller is located on the outer side of the lead screw.

[0012] Preferably, connection plates are fixedly connected to both the front side and the rear side of the positioning rod, and the connection plates are fixedly connected to the outer side of the internal thread ring.

[0013] Preferably, the sleeve includes an outer tube arranged on the outer side of the internal thread ring, and the outer tube is located on the outer sides of the first roller and the second roller.

[0014] Preferably, a thread groove is formed inside the outer tube, and the thread groove is threadedly connected to the outer side of the internal thread ring.

[0015] Preferably, a flange is fixedly connected to the front side of the outer tube, and the flange is located on the outer side of the lead screw.

[0016] Preferably, connection holes are formed in the front side of the flange, and a wear-resistant coating is applied inside the connection holes.

[0017] Preferably, the outer side of the internal thread ring is in a spiral arc shape, and the surface of the internal thread ring is in a concave-convex state.

[0018] Preferably, the surfaces of both the first roller and the second roller are in an arc shape, and the inner sides of the first roller and the second roller are both in contact with the outer side of the lead screw.

[0019] Compared with the prior art, the beneficial effects of the present utility model are:

[0020] 1. By providing a roller mechanism, this application utilizes the threaded connection between the internal thread ring and the sleeve, as well as its connection with the fixed shaft and the first roller, to provide stable radial and circumferential support for the first roller. At the same time, through the cooperation of the auxiliary rotation structure with the first roller, the constrained movement of its lead screw is further increased, ensuring that the first roller and the auxiliary rotation structure can stably move around the lead screw under complex working conditions of high speed, heavy load, or frequent start-stop, significantly improving the working reliability and load-bearing capacity of the planetary roller screw pair;

[0021] 2. By providing an auxiliary rotation structure, this application realizes strengthening the movement support and limiting of its lead screw. At the same time, it also further strengthens the stability of the first roller, adding a solid foundation to the entire roller mechanism. The first roller and the auxiliary rotation structure work together to ensure that the movement around the lead screw is more stable and orderly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the overall structure diagram of the planetary roller screw pair of the present utility model;

[0023] Figure 2 is the structure diagram of the lead screw of the present utility model;

[0024] Figure 3 is the structure diagram of the sleeve of the present utility model;

[0025] Figure 4 is the structure diagram of the roller mechanism of the present utility model;

[0026] Figure 5 is the structure diagram of the auxiliary rotation structure of the present utility model;

[0027] Figure 6 is the structure diagram of the wear-resistant coating of the present utility model.

[0028] In the figure, 1. Sleeve; 101. Outer tube; 102. Thread groove; 2. Roller mechanism; 201. Internal thread ring; 202. Fixed shaft; 203. First roller; 204. Auxiliary rotation structure; 2041. Positioning rod; 2042. Second roller; 2043. Connection plate; 3. Lead screw; 4. Flange plate; 5. Connection hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0030] Please refer to Figure 1-6 , the present utility model provides the following technical solutions:

[0031] A planetary roller screw pair includes a sleeve 1, a roller mechanism 2 is arranged inside the sleeve 1, and a lead screw 3 is arranged inside the roller mechanism 2;

[0032] The roller mechanism 2 includes internal thread rings 201 respectively threadedly connected to the front side and the rear side inside the sleeve 1. A fixed shaft 202 is rotatably connected to the inner side of the internal thread ring 201. A first roller 203 is fixedly connected to the outer side of the fixed shaft 202. The first roller 203 is located on the outer side of the lead screw 3. An auxiliary rotation structure 204 is arranged inside the internal thread ring 201, and the auxiliary rotation structure 204 is located on the outer side of the lead screw 3.

[0033] In this embodiment: By arranging the sleeve 1, the roller mechanism 2 and the lead screw 3, when an external driving force acts on the lead screw 3 to make it rotate, a spiral fit between the lead screw 3 and the first roller 203 generates an axial force, prompting the first roller 203 to have a movement tendency along the axial direction of the lead screw 3. At this time, the internal thread ring 201 is firmly positioned inside the sleeve 1 through threaded connections with the front side and the rear side inside the sleeve 1. The fixed shaft 202 rotatably connected to its inner side provides a reliable radial support for the first roller 203, enabling the first roller 203 to stably perform circular motion around the lead screw 3. At the same time, the auxiliary rotation structure 204 inside the internal thread ring 201 further optimizes the movement process and works in coordination with the first roller 203. When the first roller 203 rotates driven by the lead screw 3, the auxiliary rotation structure 204 rotates synchronously, precisely guiding and restricting the movement of the lead screw 3. Under complex working conditions such as high-speed heavy load or frequent start-stop, this structural design can effectively resist the tilting moment generated by the helix angle, prevent the first roller 203 and the auxiliary rotation structure 204 from sliding or self-rotating. The first roller 203 and the auxiliary rotation structure 204 jointly move stably around the lead screw 3, ensuring that the planetary roller screw pair accurately and efficiently converts rotational motion into linear motion, while significantly improving the working reliability and load-bearing capacity, reducing wear between components, and extending the service life of the entire device.

[0034] Specifically, as Figure 5 shown, the auxiliary rotation structure 204 includes a positioning rod 2041 arranged at the triangle inside the internal thread ring 201, and the outer side of the positioning rod 2041 penetrates through the inside of the internal thread ring 201.

[0035] Specifically, as Figure 5 shown, a second roller 2042 is rotatably connected to the outer side of the positioning rod 2041. The second roller 2042 is located inside the adjacent first roller 203, and the second roller 2042 is located on the outer side of the lead screw 3.

[0036] Specifically, as Figure 5As shown, the front and rear sides of the positioning rod 2041 are fixedly connected with connecting plates 2043 , and the connecting plates 2043 are fixedly connected to the outer side of the internal thread ring 201 .

[0037] In this embodiment: the positioning rod 2041 in the auxiliary rotation structure 204 is triangularly distributed inside the internal thread ring 201 and penetrates the outside, thereby laying a foundation for accurate positioning and stable support for the roller mechanism 2; the second roller 2042, which is rotatably connected to the positioning rod 2041 and located on the inner side of the adjacent first roller 203, cooperates with the first roller 203 to share the load of the screw 3, reduces the pressure of the first roller 203, reduces wear, enhances the bearing capacity of the roller mechanism 2, ensures stable operation under complex working conditions, extends the life of the first roller 203, and improves the overall durability of the device; the connecting plate 2043 is fixed to the front and rear sides of the positioning rod 2041 and connected to the internal thread ring 201, enhances the rigidity of the component connection, prevents relative displacement between the positioning rod 2041 and the internal thread ring 201, stabilizes the motion constraint of the second roller 2042, thereby improving the motion reliability and accuracy of the planetary roller screw pair, and reducing the risk of failure.

[0038] Specifically, Figure 3 As shown, the sleeve 1 includes an outer tube 101 arranged outside the inner thread ring 201 , and the outer tube 101 is located outside the first roller 203 and the second roller 2042 .

[0039] Specifically, Figure 3 As shown, a thread groove 102 is formed inside the outer tube 101 , and the thread groove 102 is threadably connected to the outer side of the inner thread ring 201 .

[0040] In this embodiment: by setting the outer tube 101 and the thread groove 102, the outer tube 101 is located outside the first roller 203 and the second roller 2042, and the internal thread groove 102 is threadedly connected with the internal thread ring 201, providing external protection and support for the roller mechanism 2, ensuring that the internal thread ring 201 is firmly installed, preventing displacement and shaking, blocking impurities, reducing wear and jamming, maintaining a good working condition, and extending the service life of the planetary roller screw pair.

[0041] Specifically, Figure 3 As shown, a flange 4 is fixedly connected to the front side of the outer tube 101 , and the flange 4 is located on the outside of the screw rod 3 .

[0042] Specifically, Figure 3 As shown, a connection hole 5 is opened on the front side of the flange 4, and the inside of the connection hole 5 is coated with a wear-resistant coating.

[0043] In this embodiment: By providing the flange 4 and the connection hole 5, the flange 4 on the front side of the outer tube 101 is located outside the lead screw 3. The connection hole 5 thereon facilitates connection and positioning with external devices, ensuring the correct position in the mechanical system, effectively transmitting external loads, guaranteeing connection reliability and stability, and enhancing the collaborative working ability of the entire mechanical system. At the same time, the wear-resistant coating in the connection hole 5 on the front side of the flange 4 reduces the friction coefficient during installation and disassembly, reduces the wear and corrosion of the inner wall of the connection hole 5, maintains dimensional accuracy and surface quality, and ensures the tight fit of the bolts.

[0044] Specifically, as Figure 6 shown, the outer side of the internal thread ring 201 is in a spiral arc shape, and the surface of the internal thread ring 201 is in a concave-convex state.

[0045] Specifically, as Figure 4 、 Figure 5 shown, the surfaces of the first roller 203 and the second roller 2042 are both in an arc shape, and the inner sides of the first roller 203 and the second roller 2042 are both in contact with the outer side of the lead screw 3.

[0046] In this embodiment: Due to the spiral arc shape and concave-convex surface of the outer side of the internal thread ring 201, it closely cooperates with the thread groove 102 of the sleeve 1. The concave-convex surface increases the friction force to prevent loosening, improves the installation stability of the roller mechanism 2, the spiral arc shape optimizes the force distribution, and reduces the risk of damage. Also, the surfaces of the first roller 203 and the second roller 2042 are in an arc shape and the inner sides are in contact with the lead screw 3, forming a line contact or an approximate line contact, reducing the friction resistance, lowering the energy loss, enhancing the transmission efficiency, making the movement smooth, reducing wear and jamming, prolonging the service life of the first roller 203, the second roller 2042 and the lead screw 3, and ensuring the long-term stable and efficient operation of the planetary roller screw pair.

[0047] Working principle: When the planetary roller screw pair is operating, an external driving force causes the lead screw 3 to rotate. The lead screw 3 is helically engaged with the first roller 203 to generate an axial force, pushing the first roller 203 to have a tendency of axial movement. At this time, the inner thread ring 201 is positioned therein through threaded connections on the front and rear sides with the sleeve 1, and its inner fixed shaft 202 provides radial support for the first roller 203 to ensure the stable movement of the first roller 203 around the circumference of the lead screw 3. This is the basis for motion conversion. The auxiliary rotation structure 204 inside the inner thread ring 201 is crucial. The positioning rods 2041 are distributed in a triangular shape and penetrate through the inner thread ring 201 to construct a stable framework for precise positioning and support. The second roller 2042 is located inside the adjacent first roller 203 and is rotatably connected to the positioning rod 2041. When the first roller 203 rotates with the lead screw 3, the second roller 2042 cooperates to share the load, making the forces on the first roller 203 and the second roller 2042 uniform, reducing wear, and enhancing the load-bearing capacity. The connecting plate 2043 is fixed to the front and rear of the positioning rod 2041 and is connected to the inner thread ring 201 to enhance the rigidity of the auxiliary rotation structure 204. The outer tube 101 of the sleeve 1 is located outside the first roller 203 and the second roller 2042, and its thread groove 102 is threadedly connected to the inner thread ring 201. It not only protects the first roller 203 and the second roller 2042 from impurity intrusion, reduces wear and jamming, and maintains a good working state, but also ensures the firm installation of the inner thread ring 201, stabilizes the overall structure, and extends the service life. The flange 4 on the front side of the outer tube 101 is located outside the lead screw 3, and is convenient for connecting and positioning with external equipment through the connection hole 5, ensuring the correct position in the mechanical system, effectively transmitting the external load, and enhancing the cooperative working ability of the system. The wear-resistant coating in the connection hole 5 of the flange 4 reduces the friction coefficient during installation and disassembly, reduces wear and corrosion, maintains the precision and quality of the connection hole 5, ensures the tight fit of the bolts, improves the convenience and reliability of installation and use, extends the life of the flange 4, and reduces the maintenance cost. In short, the cooperation of each component enables the planetary roller screw pair to resist the tilting moment under complex working conditions. At the same time, it prevents the first roller 203 and the second roller 2042 from sliding or spinning, precisely and efficiently converts motion, improves the working reliability, load-bearing capacity, reduces wear, extends the life, and ensures the stable operation of mechanical equipment.

[0048] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A planetary roller screw pair, comprising a sleeve (1), characterized in that: A roller mechanism (2) is arranged inside the casing (1), and a lead screw (3) is arranged inside the roller mechanism (2); The roller mechanism (2) includes internal thread rings (201) respectively threadedly connected to the front side and the rear side inside the casing (1). A fixed shaft (202) is rotatably connected to the inner side of the internal thread ring (201). A first roller (203) is fixedly connected to the outer side of the fixed shaft (202). The first roller (203) is located on the outer side of the lead screw (3). An auxiliary rotation structure (204) is arranged inside the internal thread ring (201), and the auxiliary rotation structure (204) is located on the outer side of the lead screw (3).

2. The planetary roller screw pair according to claim 1, characterized in that: The auxiliary rotation structure (204) includes positioning rods (2041) arranged in a triangle inside the internal thread ring (201), and the outer sides of the positioning rods (2041) penetrate through the inside of the internal thread ring (201).

3. The planetary roller screw pair according to claim 2, characterized in that: A second roller (2042) is rotatably connected to the outer side of the positioning rod (2041). The second roller (2042) is located inside the adjacent first roller (203), and the second roller (2042) is located on the outer side of the lead screw (3).

4. A planetary roller screw pair according to claim 2, characterized in that: Connection plates (2043) are fixedly connected to both the front side and the rear side of the positioning rod (2041), and the connection plates (2043) are fixedly connected to the outer side of the internal thread ring (201).

5. A planetary roller screw pair according to claim 1, characterized in that: The casing (1) includes an outer tube (101) arranged on the outer side of the internal thread ring (201), and the outer tube (101) is located on the outer sides of the first roller (203) and the second roller (2042).

6. The planetary roller screw pair according to claim 5, wherein: Thread grooves (102) are formed inside the outer tube (101), and the thread grooves (102) are threadedly connected to the outer side of the internal thread ring (201).

7. A planetary roller screw pair according to claim 5, characterized in that: A flange plate (4) is fixedly connected to the front side of the outer tube (101), and the flange plate (4) is located on the outer side of the lead screw (3).

8. A planetary roller screw pair according to claim 7, characterized in that: Connection holes (5) are formed in the front side of the flange plate (4), and wear-resistant coatings are applied inside the connection holes (5).

9. A planetary roller screw pair according to claim 1, characterized in that: The outer side of the internal thread ring (201) is in a spiral arc shape, and the surface of the internal thread ring (201) is in a concave-convex state.

10. A planetary roller screw pair according to claim 3, characterized in that: The surfaces of the first roller (203) and the second roller (2042) are both in an arc shape, and the inner sides of the first roller (203) and the second roller (2042) are both in contact with the outer side of the lead screw (3).

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