CN212564277U - Planetary roller screw with involute helicoid - Google Patents
Planetary roller screw with involute helicoid Download PDFInfo
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- CN212564277U CN212564277U CN202020542352.0U CN202020542352U CN212564277U CN 212564277 U CN212564277 U CN 212564277U CN 202020542352 U CN202020542352 U CN 202020542352U CN 212564277 U CN212564277 U CN 212564277U
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Abstract
The utility model relates to a planet roller lead screw with helicoid that gradually bursts at seams, including lead screw, nut, roller, be connected through the roller transmission between lead screw and the nut, and be transmission threaded connection between roller and lead screw, the nut, the thread flank of roller is the thread side of gradually bursting at seams, the thread flank of lead screw and nut is the thread side of gradually bursting at seams or the tangent plane. The side of the thread is composed of involute helicoids, one thread tooth is composed of a pair of involute helicoids, and the two involute helicoids are symmetrically distributed on two sides of the thread tooth. The utility model discloses make the contact of roller and lead screw, nut be line contact, promotion planet roller screw's bearing capacity that can be by a wide margin. In particular, the tooth shape of the mode can reduce adverse effects such as edge occlusion and reduction of bearing capacity under the conditions of large screw pitch and high transmission ratio.
Description
Technical Field
The utility model relates to a planet roller lead screw, especially a change rotary motion into linear motion's planet screw drive mechanism.
Background
Compared with a ball screw, the roller screw has the characteristics of stronger bearing capacity, higher speed, higher precision, longer service life, low maintenance cost and the like, thereby becoming one of the most critical basic parts in precision mechanical equipment such as aviation machinery, numerical control machines, precision instruments, meters and the like and being widely applied.
As shown in fig. 1, the planetary roller screw includes a screw 1, a nut 3, rollers 4, an inner gear ring 2, a planet carrier 5, a retainer ring 6, and the like. The planetary roller screw can be divided into three types, namely a standard type, a nut type and a circulating type according to the relative movement form among the rollers, the nut and the screw in the transmission process, wherein the standard type rollers and the nut are axially kept relatively static, the nut type rollers and the screw are axially kept relatively static, and the circulating type rollers move back and forth relative to the nut in an axial periodic mode.
In the specific movement process, the roller threads are respectively meshed with the screw threads of the lead screw and the nut threads to transmit power. When the screw rod rotates, the nut moves along the axis of the screw rod, and the rollers rotate and do planetary motion around the screw rod at the same time, and the axial moving speed of the rollers is kept the same as that of the nut. The rotational motion is converted into a linear motion by the above-mentioned motion.
During the transmission, the thread contact points of the plane profile are many, but the diameter of the contact point of the roller and the screw (nut) can not be kept constant. In order to obtain a precise lead, which must ensure stability and accuracy of the thread contact points, the thread profiles of the rollers and the screw (nut) should have at least one curved surface. In the conventional design, the screw 1 and the nut 3 are triangular threads having the same number of threads, and the normal (axial) profile is a straight line; whereas the rollers 4 are generally single-start threads with a normal (axial) profile in the form of a circular arc R. The profile angle a of the thread is typically 90, as shown in particular in fig. 2(a), (b), (c). A conventional roller screw nut engagement is shown in fig. 3. In order to ensure that the diameter of the contact point of the roller and the screw rod is kept constant, the traditional planetary roller thread form adopts a form that a straight line is in contact with an arc to ensure that the diameter of the contact point is kept constant. Because the screw threads of the roller and the screw rod rotate in the same direction, the contact point between the roller and the screw rod is near the pitch diameter of the screw threads, but not completely at the pitch diameter of the screw threads; ideally, the contact point between the roller and the nut is at the pitch diameter, however, in practice, the contact point may deviate from the ideal position due to machining and assembly errors. The deviation of the contact point enables the roller to slide on the contact point with the screw rod and the nut, and the transmission performance of the planetary roller screw, such as bearing, friction, abrasion, efficiency, lubrication and the like, is seriously influenced. Especially, the transmission ratio among the roller, the screw rod and the nut depends on processing and assembly seriously, and the transmission ratio is influenced by the installation center distance and deflection. Moreover, the tooth shape of the form causes the contact of the roller with the screw and the nut to be point contact, and the bearing capacity of the planetary roller screw is greatly reduced.
Disclosure of Invention
In order to further improve planet roller screw's bearing capacity, and eliminate because processing, the intermeshing between the influence planet roller screw such as assembly, lead screw, the nut three, guarantee that the drive ratio between the three does not receive the influence of contact point position in transmission process, the utility model provides a planet roller screw with helicoid that gradually bursts at seams, this planet roller screw inherits the helical gear transmission's that gradually bursts at seams advantage, greatly reduced the roller, lead screw, the transmission of nut three receives the assembly, the influence of processing, guarantee driven stability, simultaneously, the planet roller screw that has the helicoid that gradually bursts at seams, contact between them is line contact, can improve planet roller screw's bearing capacity greatly.
In order to achieve the above purpose, the technical scheme of the utility model is that: the utility model provides a planet roller lead screw of helicoid screw gradually bursts at seams, includes lead screw, nut, roller, is connected through the roller transmission between lead screw and the nut, and is transmission threaded connection between roller and lead screw, the nut, the thread flank of roller is the thread side of spiraling at seams, the thread flank of lead screw and nut is the thread side or the straight line face of spiraling at seams.
Furthermore, the side surface of the thread is composed of involute helicoids, one thread tooth is composed of a pair of involute helicoids, and the two involute helicoids are positioned on the two sides of the thread tooth and symmetrically distributed.
Further, when the screw thread turning directions of the roller and the nut are the same and the screw thread rising angles are equal, the thread thicknesses of the end face thread forms of the roller and the nut at the screw thread middle diameter are equal; the ratio of the involute base circles of the roller and the nut satisfies the following relation:
wherein k is1Number of thread starts of nut, k2Number of thread starts of roller, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
Further, when the lead screw adopts a triangular thread with a linear profile or a thread with an involute spiral surface, the number of thread heads is the same as that of the nuts; the base radius of the involute of the end surface of the lead screw is related to the roller and the nut, and the specific relationship is as follows:
Rs＝Rn-2Rr
wherein R issIs the involute base radius of the screw rod, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
Further, when the screw thread turning directions of the roller and the screw thread are the same, and the thread rising angles are equal, the tooth thicknesses of the end face tooth forms of the roller and the screw thread at the middle diameter of the screw thread are equal; the ratio of the roller to the base circle of the involute of the screw rod satisfies the following relationship:
wherein k issNumber of thread starts of the screw, krNumber of thread starts of roller, RrThe base radius of involute of roller, RsThe involute base radius of the screw.
Further, when the nut adopts a triangular thread with a linear profile or a thread with an involute spiral surface, the number of thread heads is the same as that of the screw rod; the base radius of the involute of the end surface of the nut is related to the roller and the screw rod, and the specific relationship is as follows:
Rn＝Rs+2Rr
wherein R isnBase radius of involute of nut, RsInvolute base radius of screw, RrIs the involute base radius of the roller.
Further, the screw rod and the nut are threads with the same number of heads, and the side surface of each thread is a linear surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
Furthermore, the screw rod and the nut are threads with the same number of heads, and the side surface of each thread is an involute thread rotary surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
Furthermore, the screw rod and the nut are threads with the same number of heads, the thread side surface of the screw rod is an involute thread rotary surface, and the thread side surface of the nut is a linear surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
Furthermore, the screw rod and the nut are threads with the same number of heads, the thread side surface of the screw rod is a linear surface, and the thread side surface of the nut is an involute thread rotary surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
The utility model has the advantages that:
the utility model provides a pair of involute helicoid planet roller screw thread that is helical engagement each other, in the meshing scope of allowwing, no matter lay them on how centre-to-centre spacing and crossing angle, its transmission speed ratio is invariable, is that centre-to-centre spacing and crossing angle divide equally promptly, transmission error and the unstability that greatly reduced installation manufacturing led to.
The tooth shape of the form enables the contact of the roller with the screw rod and the nut to be line contact, and the bearing capacity of the planetary roller screw can be greatly improved. In particular, the tooth shape of the mode can reduce adverse effects such as edge occlusion and reduction of bearing capacity under the conditions of large screw pitch and high transmission ratio.
Drawings
FIG. 1 is a schematic diagram of a prior art planetary roller screw assembly;
FIG. 2 is a prior art planetary roller screw profile;
wherein: (a) a roller, (b) a nut, (c) a screw;
FIG. 3 is a diagram of the engagement of a roller, a nut and a screw in a conventional planetary roller screw;
FIG. 4 is an involute helicoid thread drawing;
FIG. 5 is an involute helicoid view;
FIG. 6 is a thread end profile of an involute thread profile;
FIG. 7 is a schematic view of an involute profile modification;
fig. 8 is a meshing diagram of the involute profile roller, the nut and the lead screw of the utility model.
Detailed Description
The present invention will be further explained with reference to the accompanying drawings and examples.
As shown in fig. 4 and 8, the utility model discloses a planetary roller screw with involute helicoid threads, including screw 1, nut 3, roller 4, be connected through roller 4 transmission between screw 1 and the nut 3, and be connected for transmission threaded connection between roller 4 and screw 1, the nut 3. The thread side of the roller 4 is an involute thread rotary surface JL, and the thread side of the screw rod 1 and the nut 3 is the involute thread rotary surface JL or a linear surface L.
As shown in fig. 4, the flank of the thread is constituted by an involute spiral face JL. One thread tooth is composed of a pair of involute helicoids JL, and the two involute helicoids JL are positioned at two sides of the thread tooth and distributed symmetrically. The number of threads of the lead screw, i.e. the number of starts of the thread, is dependent on the specific design.
As shown in fig. 5, in general, a curved surface composed of a tangent to a cylindrical spiral is called an involute spiral surface. The spiral line becomes base circle spiral line T, and the cylinder that this spiral line belonged to is base cylinder U, and the tangent line of base circle spiral line is straight generating line W.
An important property of the involute helicoid is that its end section (as in figure 6) is involute J, the base radius of which is the radius of the base cylinder. It should be noted that only the end cross section is involute, and the normal cross section is not involute. Thus, the end involute of the planetary roller spindle thread of the involute spiral can be initially produced, by which the involute spiral is formed with an involute spiral motion around the spiral.
In the specific implementation, the thread directions of the roller and the nut are the same and the lead angles are the same for the standard product. In the design process, in order to ensure the stability of mutual meshing between the two, the design is generally as follows: (1) the tooth thickness of the end face tooth forms of the two threads at the middle diameter of the thread is equal; (2) the ratio of the base circle of the involute of the two satisfies the following relation:
wherein k is1Number of thread starts of nut, k2Number of thread starts of roller, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
The screw rod can be designed by adopting a triangular thread with a straight profile or a thread with an involute helicoid, and the number of the heads of the screw rod is the same as that of the nut. If an involute helicoid is adopted, the base radius of the involute on the end face of the screw rod is related to the roller and the nut, and the specific relationship is as follows:
Rs＝Rn-2Rr
wherein R issIs the involute base radius of the screw rod, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
In addition, when the screw rod and the roller are meshed with each other, the screw rod needs to be modified, and the specific method is to establish an equidistant involute of an initial involute, wherein the equidistant involute and the initial involute have the same base circle, the equidistant involute and the initial involute are different only in starting point, and simultaneously the thread form angle alpha of the thread can be ensured to be kept unchanged, so that the property is very beneficial to the transmission of the thread. As shown in fig. 7The involute profile is translated from position M1 to position M2, and tooth thickness is changed from B 'B to B'xBxBut the tooth form angle and the tooth profile shape are not changed.
In the nut type product, the screw thread directions of the roller and the screw rod are the same, and the lead angles are the same. In the design process, in order to ensure the stability of mutual meshing between the two, the design is generally as follows: (1) the tooth thickness of the end face tooth forms of the two threads at the middle diameter of the thread is equal; (2) the ratio of the base circle of the involute of the two satisfies the following relation:
wherein k issNumber of thread starts of the screw, krNumber of thread starts of roller, RrThe base radius of involute of roller, RsThe involute base radius of the screw.
The nut can be designed by adopting a triangular thread with a straight line profile or a thread with an involute helicoid, and the number of the heads of the nut is the same as that of the screw rod. If an involute helicoid is adopted, the base radius of the involute on the end surface of the nut is related to the roller and the screw rod, and the specific relationship is as follows:
Rn＝Rs+2Rr
wherein R isnThe involute base radius of the nut.
The mutual meshing relationship among the roller, the screw rod and the nut is shown in figure 8 by applying the involute tooth form. This involute helicoid build is equally applicable to other forms of planetary roller screws.
Wherein: (1) the screw rod 1 and the nut 3 are threads with the same number of heads, and the side surface of each thread is a linear surface L; the roller 4 is a single thread, and the side surface of the thread is an involute thread rotating surface JL. (2) The screw rod 1 and the nut 3 are threads with the same number of heads, and the side surface of each thread is an involute thread rotating surface JL; the roller 4 is a single thread, and the side surface of the thread is an involute thread rotating surface JL. (3) The screw 1 and the nut 3 are threads with the same number of heads, the thread side surface of the screw is an involute thread rotating surface JL, and the thread side surface of the nut 3 is a linear surface L; the roller 4 is a single thread, and the side surface of the thread is an involute thread rotating surface JL. (4) The screw 1 and the nut 3 are threads with the same number of heads, the thread side surface of the screw is a linear surface L, and the thread side surface of the nut 3 is an involute thread rotating surface JL; the roller 4 is a single thread, and the side surface of the thread is an involute thread rotating surface JL.
The present invention is not limited to the above-mentioned examples, and various modifications and changes which can be made by those skilled in the art without creative work are protected by the present invention within the scope defined by the claims of the present invention.
Claims (10)
1. The utility model provides a planet roller lead screw with involute helicoid, includes lead screw, nut, roller, is connected through roller transmission between lead screw and the nut, and is transmission threaded connection, its characterized in that between roller and lead screw, the nut: the thread side surface of the roller is an involute thread rotary surface, and the thread side surfaces of the lead screw and the nut are involute thread rotary surfaces or linear surfaces.
2. A planetary roller screw with involute helicoids, according to claim 1, wherein: the side of the thread is composed of involute helicoids, one thread tooth is composed of a pair of involute helicoids, and the two involute helicoids are symmetrically distributed on two sides of the thread tooth.
3. A planetary roller screw with involute helicoids, according to claim 1, wherein: when the screw thread turning directions of the roller and the nut are the same and the screw thread rising angles are equal, the tooth thicknesses of the end face tooth forms of the roller and the nut at the middle diameter of the screw thread are equal; the ratio of the involute base circles of the roller and the nut satisfies the following relation:
wherein k is1Number of thread starts of nut, k2Number of thread starts of roller, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
4. A planetary roller screw with involute helicoids, according to claim 1, wherein: when the screw rod adopts a triangular thread with a linear profile or a thread with an involute helicoid, the number of the thread heads is the same as that of the nuts; the base radius of the involute of the end surface of the lead screw is related to the roller and the nut, and the specific relationship is as follows:
Rs＝Rn-2Rr
wherein R issIs the involute base radius of the screw rod, RrThe base radius of involute of roller, RnThe involute base radius of the nut.
5. A planetary roller screw with involute helicoids, according to claim 1, wherein: when the thread turning directions of the roller and the screw rod are the same and the thread lifting angles are equal, the thread thicknesses of the end face thread forms of the roller and the screw rod at the middle diameter of the thread are equal; the ratio of the roller to the base circle of the involute of the screw rod satisfies the following relationship:
wherein k issNumber of thread starts of the screw, krNumber of thread starts of roller, RrThe base radius of involute of roller, RsThe involute base radius of the screw.
6. A planetary roller screw with involute helicoids, according to claim 1, wherein: when the nut adopts triangular threads with linear profile or threads with involute helicoids, the number of the thread heads is the same as that of the screw rod; the base radius of the involute of the end surface of the nut is related to the roller and the screw rod, and the specific relationship is as follows:
Rn＝Rs+2Rr
wherein R isnInvolute of nutRadius of base circle, RsInvolute base radius of screw, RrIs the involute base radius of the roller.
7. A planetary roller screw with involute helicoids, according to claim 1, wherein: the screw rod and the nut are threads with the same number of heads, and the side surface of each thread is a linear surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
8. A planetary roller screw with involute helicoids, according to claim 1, wherein: the screw rod and the nut are threads with the same number of heads, and the side surface of each thread is an involute thread rotary surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
9. A planetary roller screw with involute helicoids, according to claim 1, wherein: the screw rod and the nut are threads with the same number of heads, the thread side surface of the screw rod is an involute thread rotary surface, and the thread side surface of the nut is a linear surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
10. A planetary roller screw with involute helicoids, according to claim 1, wherein: the screw rod and the nut are threads with the same number of heads, the thread side surface of the screw rod is a linear surface, and the thread side surface of the nut is an involute thread rotary surface; the roller is a single-head thread, and the side surface of the thread is an involute thread rotary surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020542352.0U CN212564277U (en) | 2020-04-13 | 2020-04-13 | Planetary roller screw with involute helicoid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020542352.0U CN212564277U (en) | 2020-04-13 | 2020-04-13 | Planetary roller screw with involute helicoid |
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| Publication Number | Publication Date |
|---|---|
| CN212564277U true CN212564277U (en) | 2021-02-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020542352.0U Active CN212564277U (en) | 2020-04-13 | 2020-04-13 | Planetary roller screw with involute helicoid |
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| CN (1) | CN212564277U (en) |
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2020
- 2020-04-13 CN CN202020542352.0U patent/CN212564277U/en active Active
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