Planetary roller screw mechanism
By combining the worm gear and the planetary roller screw to form a high-speed reduction ratio mechanism, and using the meshing transmission of the worm gear and worm gear to have self-locking capabilities, the existing planetary roller screws are solved inappropriate in high load and low thrust speed occasions, achieving efficient high thrust output and cost savings.
Patent Information
- Application Number
- CN202422056345.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-08-23
AI Technical Summary
Existing planetary roller screws are not suitable for high load and low push speed occasions, making them difficult to manufacture and require a large motor, which increases space and cost, and lacks self-locking or braking capabilities.
Combining the worm gear and the planetary roller screw to form a high reduction ratio mechanism to convert the motor high speed into the planetary roller screw high thrust, and having self-locking ability through the meshing transmission of the worm gear and worm gear to avoid additional brakes.
It realizes high-reduction ratio transmission, has self-locking ability, saves costs, reduces the space for installing brakes, and improves the applicability of planetary roller screws in high load and low push speed occasions.
Smart Images
Figure CN222864024U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of planetary roller screws, in particular to a planetary roller screw mechanism. Background Art
[0002] At present, planetary roller screws are increasingly widely used due to their long life and high efficiency. However, some of the current planetary roller screws are not suitable for use in some high-load, low-speed applications. The reason is that low-lead planetary roller screws are difficult to manufacture, and large torques generally require large motors, which will increase the space and cost of large motors. In addition, the current planetary roller screws do not have self-locking or braking capabilities. It can be seen that the current planetary roller screws still have certain defects. Utility Model Content
[0003] In response to the technical problems of defects in existing planetary roller screws, the utility model provides a planetary roller screw mechanism, which combines a worm gear with a planetary roller screw to form a high reduction ratio mechanism, thereby converting the high speed of the motor into the high thrust of the planetary roller screw. At the same time, the meshing transmission of the worm gear gives the mechanism self-locking capability, eliminating the need for additional brakes, saving costs, and reducing the space for installing brakes.
[0004] The technical solution provided by the utility model is: a planetary roller screw mechanism, including a screw, a worm wheel is fixedly arranged on the screw, a worm is arranged on one side of the screw, and the worm wheel and the worm are meshed; a threaded section is arranged on the screw, the threaded section is located on one side of the worm wheel, a nut is arranged on the outer side of the threaded section, a plurality of rollers are arranged around the threaded section and the nut, the rollers are threadedly meshed with the threaded section and the nut, and a push rod is fixedly connected to the side of the nut away from the worm wheel.
[0005] Optionally, it also includes two retaining frames and two inner gear rings; the two inner gear rings are respectively fixed to the two ends of the nut, the inner ring of the inner gear ring is provided with inner teeth, and the two ends of the roller are respectively provided with outer teeth meshing with the inner teeth; the retaining frame is located on the inner side of the inner gear ring, and the two ends of the roller are respectively engaged with the two retaining frames.
[0006] Optionally, a nut sleeve is fixedly provided on the outside of the nut, and a cylinder is fixedly provided on the outside of the nut sleeve; a second cylinder head is fixedly provided on one side of the cylinder, and a first cylinder head is fixedly provided on the other side of the cylinder, and the worm wheel and at least part of the worm are located in the first cylinder head.
[0007] Optionally, an extension section is provided at one end of the lead screw close to the worm gear, a first angular contact ball bearing and a second angular contact ball bearing are provided between the extension section and the first cylinder head, and the first angular contact ball bearing and the second angular contact ball bearing are configured in the form of a DB combination.
[0008] Optionally, a shoulder is provided on the extension section, and the shoulder abuts against the end face of the second angular contact ball bearing. A locking piece is fixedly provided at the end of the extension section, and a bearing cover plate is fixedly provided on one side of the first cylinder head, and the bearing cover plate and the locking piece both abut against the end face of the first angular contact ball bearing.
[0009] Optionally, a front bearing cover and a rear bearing cover are provided on the first cylinder head, the worm passes through the front bearing cover and the rear bearing cover, the worm is sleeved with a front bearing near the front bearing cover, and the worm is sleeved with a rear bearing near the rear bearing cover, and the outer rings of the front bearing and the rear bearing are both in contact with the first cylinder head.
[0010] Optionally, a sliding bearing is sleeved on the outer side of the push rod near the second cylinder head, and the outer ring of the sliding bearing abuts against the second cylinder head.
[0011] Optionally, a flat portion is provided on the inner side of the cylinder, and an anti-rotation plane is provided on the outer side of the nut sleeve, and the flat portion abuts against the anti-rotation plane.
[0012] Optionally, a fixing rod is fixedly connected between the first cylinder head and the second cylinder head, and the fixing rod is located outside the cylinder barrel.
[0013] Beneficial Effects
[0014] The technical solution provided by the utility model has the following beneficial effects compared with the prior art: in response to the technical problems of defects in the existing planetary roller screws, the utility model combines the worm gear with the planetary roller screw to form a high reduction ratio mechanism, thereby realizing the conversion of the high speed of the motor into the high thrust of the planetary roller screw. At the same time, the meshing transmission of the worm gear gives the mechanism a self-locking ability, without the need for additional brakes, saving costs and reducing the space for installing the brakes. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a schematic structural diagram of a planetary roller screw mechanism proposed in an embodiment of the utility model.
[0016] Figure 2 The present invention is a schematic cross-sectional view of a planetary roller screw mechanism according to an embodiment of the present invention.
[0017] Figure 3This is a schematic diagram of the internal structure of a planetary roller screw mechanism proposed in an embodiment of the utility model.
[0018] Figure 4 This is a schematic diagram of the structure of the cylinder barrel proposed in an embodiment of the utility model. DETAILED DESCRIPTION
[0019] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.
[0020] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant utility model, rather than to limit the utility model. It should also be noted that, for the convenience of description, only the parts related to the utility model are shown in the accompanying drawings. The words "first", "second", etc. described in the present utility model are set for the convenience of describing the technical solution of the present utility model, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present utility model. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments in the present application can be combined with each other. In the description of the present utility model, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model 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 cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not have contradictions or conflicts, all of which are within the scope of protection required by the present utility model.
[0021] Example 1
[0022] Combined with Figure 1-4The present embodiment proposes a planetary roller screw mechanism, including a screw 32, a worm wheel 321 is fixedly arranged on the screw 32, a worm 31 is arranged on one side of the screw 32, and the worm wheel 321 and the worm 31 are meshed; a threaded section is arranged on the screw 32, the threaded section is located on one side of the worm wheel 321, a nut 34 is arranged on the outer side of the threaded section, a plurality of rollers 33 are arranged around the threaded section and the nut 34, the rollers 33 are threadedly meshed with the threaded section and the nut 34, and a push rod 19 is fixedly connected to the side of the nut 34 away from the worm wheel 321.
[0023] In response to the technical problems of defects in existing planetary roller screws, this embodiment proposes a planetary roller screw mechanism, which combines a worm gear with a planetary roller screw to form a high reduction ratio mechanism, thereby converting the high speed of the motor into the high thrust of the planetary roller screw. At the same time, the meshing transmission of the worm gear gives the mechanism self-locking capability, eliminating the need for additional brakes, saving costs, and reducing the space for installing brakes.
[0024] The planetary roller screw mechanism of this embodiment has a worm 31 as an input end, and the end of the worm 31 is connected to a driving device such as a motor to connect high-speed and low-torque power. The worm 31 meshes with the worm wheel 321, and further converts the external high-speed and low-torque power into low-speed and high-torque with a high reduction ratio. Since the worm wheel 321 is fixedly connected to the screw 32, the low-speed and high-torque can be converted into a high-thrust and low-speed movement of the push rod 19 through the screw 32, the roller 33 and the nut 34. In an optional embodiment, the worm wheel 321 and the screw 32 can be an integrated structure.
[0025] The lead screw 32, roller 33 and nut 34 constitute a part consistent with the traditional planetary roller screw, and further include two retaining frames 35 and two inner gear rings 36; the two inner gear rings 36 are respectively fixed to the two ends of the nut 34, the inner ring of the inner gear ring 36 is provided with inner teeth, and the two ends of the roller 33 are respectively provided with outer teeth meshing with the inner teeth; the retaining frame 35 is located on the inner side of the inner gear ring 36, and the two ends of the roller 33 are respectively engaged with the two retaining frames 35.
[0026] In an optional embodiment, a nut sleeve 37 is fixedly disposed on the outside of the nut 34, and a cylinder 15 is fixedly disposed on the outside of the nut sleeve 37; a second cylinder head 18 is fixedly disposed on one side of the cylinder 15, and a first cylinder head 13 is fixedly disposed on the other side of the cylinder 15, and the worm wheel 321 and at least part of the worm 31 are located in the first cylinder head 13. Thus, the planetary roller screw mechanism constitutes an integrated complete structure.
[0027] Since the planetary roller screw mechanism of this embodiment is ultimately to achieve high thrust and low thrust speed movement of the push rod 19, the screw 32 will serve as the main load-bearing component. On the basis of the above-mentioned embodiment, further improvements can be made: an extension section 30 is provided at one end of the screw 32 close to the worm gear 321, and a first angular contact ball bearing 21 and a second angular contact ball bearing 25 are provided between the extension section 30 and the first cylinder head 13, and the first angular contact ball bearing 21 and the second angular contact ball bearing 25 are configured in the form of a DB combination. In this embodiment, the first angular contact ball bearing 21 and the second angular contact ball bearing 25 are in the form of a DB combination, that is, a back-to-back combination of angular contact ball bearings, and the first angular contact ball bearing 21 and the second angular contact ball bearing 25 in the back-to-back combination can withstand radial and axial loads in both directions. At this time, the first angular contact ball bearing 21 and the second angular contact ball bearing 25 can withstand the axial force of the screw 32 and provide radial positioning, thereby ensuring the stability of the planetary roller screw mechanism when it is working.
[0028] In a further embodiment, a stop shoulder is provided on the extension section 30, and the stop shoulder abuts against the end face of the second angular contact ball bearing 25, a locking member 11 is fixedly provided at the end of the extension section 30, a bearing cover plate 12 is fixedly provided on one side of the first cylinder head 13, and both the bearing cover plate 12 and the locking member 11 abut against the end face of the first angular contact ball bearing 21. In this embodiment, the locking member 11 is located at the front side of the first bearing, and works together with the bearing cover plate 12 to prevent the lead screw 32 from being pulled out. At the same time, the bearing cover plate 12 can transmit the force exerted on the first angular contact ball bearing 21 and the second angular contact ball bearing 25 to the first cylinder head 13.
[0029] And, in one embodiment, the first cylinder head 13 is provided with a front bearing cover 16 and a rear bearing cover 17, the worm 31 penetrates the front bearing cover 16 and the rear bearing cover 17, the worm 31 is sleeved with a front bearing 22 near the front bearing cover 16, the worm 31 is sleeved with a rear bearing 23 near the rear bearing cover 17, and the outer rings of the front bearing 22 and the rear bearing 23 are both in contact with the first cylinder head 13. At this time, by arranging the front bearing 22 and the rear bearing 23 at the front and rear ends of the worm 31, and assembling the worm 31 by the front bearing cover 16 and the rear bearing cover 17, radial positioning can be provided for the worm 31, and the worm 31 can be prevented from coming out.
[0030] It can be seen from the above embodiments that the nut 34 is fixedly connected to the nut sleeve 37, and the nut sleeve 37 is fixedly connected to the push rod 19, so that the thrust is output from the push rod 19 to the outside through the movement of the nut 34. In order to ensure the stability of the movement of the push rod 19, in one embodiment, a sliding bearing 24 is sleeved on the outer side of the push rod 19 near the second cylinder head 18, and the outer ring of the sliding bearing 24 abuts against the second cylinder head 18. In this case, the sliding bearing 24 can provide radial positioning for the push rod 19, the nut sleeve 37 and the nut 34 that are fixedly connected to each other, and reduce the friction resistance when the push rod 19 moves.
[0031] In one embodiment, a flat portion 151 is provided inside the cylinder 15, and an anti-rotation plane 38 is provided outside the nut sleeve 37, and the flat portion 151 abuts against the anti-rotation plane 38. Thus, the nut 34 abuts against the flat portion 151 inside the cylinder 15 through the anti-rotation plane 38, thereby preventing the nut 34 from rotating with the lead screw 32.
[0032] In other embodiments, a fixing rod 14 is fixedly connected between the first cylinder head 13 and the second cylinder head 18, and the fixing rod 14 is located outside the cylinder barrel 15. In this embodiment, the setting of the fixing rod 14 can further ensure the overall rigidity of the planetary roller screw mechanism, so that it is better suitable for high thrust and low thrust speed usage scenarios.
[0033] Combined with the above description, the planetary roller screw mechanism of this embodiment realizes a high reduction ratio transmission without increasing the axial space occupied by the reducer. A combination of a roller 33, a screw 32 and a nut 34 with a larger lead can also be used to achieve a large thrust effect, effectively reducing the manufacturing cost of the planetary roller screw. In addition, the meshing transmission of the worm wheel 321 and the worm 31 provides a self-locking capability, does not require additional brakes, saves costs, and reduces the space for installing the brake. In addition, the planetary roller screw mechanism of this embodiment makes full use of the diameter difference between the screw 32 and the nut 34 to arrange the worm wheel 321 and the worm 31, further reducing the space occupied.
[0034] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creative design without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.
Claims
1. A planetary roller screw mechanism, characterized in that: It comprises a lead screw, a worm wheel is fixedly arranged on the lead screw, a worm is arranged on one side of the lead screw, and the worm wheel and the worm are meshed; The lead screw is provided with a threaded section, the threaded section is located on one side of the worm wheel, a nut is provided on the outer side of the threaded section, a plurality of rollers are arranged around the threaded section and the nut, the rollers are threadably engaged with the threaded section and the nut, and a push rod is fixedly connected to the side of the nut facing away from the worm wheel.
2. A planetary roller screw mechanism according to claim 1, characterized in that: It also includes two retaining frames and two inner gear rings; the two inner gear rings are respectively fixed to the two ends of the nut, the inner ring of the inner gear ring is provided with inner teeth, and the two ends of the roller are respectively provided with outer teeth meshing with the inner teeth; the retaining frame is located on the inner side of the inner gear ring, and the two ends of the roller are respectively engaged with the two retaining frames.
3. A planetary roller screw mechanism according to claim 1, characterized in that: A nut sleeve is fixedly arranged on the outer side of the nut, and a cylinder is fixedly arranged on the outer side of the nut sleeve; a second cylinder head is fixedly arranged on one side of the cylinder, and a first cylinder head is fixedly arranged on the other side of the cylinder, and the worm wheel and at least part of the worm are located in the first cylinder head.
4. A planetary roller screw mechanism according to claim 3, characterized in that: An extension section is provided at one end of the lead screw close to the worm gear, a first angular contact ball bearing and a second angular contact ball bearing are provided between the extension section and the first cylinder head, and the first angular contact ball bearing and the second angular contact ball bearing are configured in the form of a DB combination.
5. A planetary roller screw mechanism according to claim 4, characterized in that: The extension section is provided with a shoulder, which abuts against the end face of the second angular contact ball bearing, and a locking piece is fixedly provided at the end of the extension section. A bearing cover plate is fixedly provided on one side of the first cylinder head, and the bearing cover plate and the locking piece both abut against the end face of the first angular contact ball bearing.
6. A planetary roller screw mechanism according to claim 3, characterized in that: A front bearing cover and a rear bearing cover are provided on the first cylinder head, the worm runs through the front bearing cover and the rear bearing cover, a front bearing is sleeved on the worm near the front bearing cover, and a rear bearing is sleeved on the worm near the rear bearing cover, and the outer rings of the front bearing and the rear bearing are both in contact with the first cylinder head.
7. A planetary roller screw mechanism according to claim 3, characterized in that: A sliding bearing is sleeved on the outer side of the push rod near the second cylinder cover, and the outer ring of the sliding bearing abuts against the second cylinder cover.
8. A planetary roller screw mechanism according to claim 3, characterized in that: A flat portion is arranged on the inner side of the cylinder barrel, and an anti-rotation plane is arranged on the outer side of the nut sleeve, and the flat portion abuts against the anti-rotation plane.
9. A planetary roller screw mechanism according to claim 3, characterized in that: A fixing rod is fixedly connected between the first cylinder head and the second cylinder head, and the fixing rod is located outside the cylinder barrel.