Nut driving type ball screw pair coupled with hyperbolic tangent and algebraic sine

Abstract

The utility model discloses a hyperbolic tangent and algebraic sine coupled nut driving type ball screw pair which comprises a ball screw and a ball nut, an inner spiral raceway is arranged on an inner hole of the ball nut, an outer spiral raceway is arranged on the outer cylindrical surface of the ball screw, and the inner spiral raceway and the outer spiral raceway are matched with each other to form a spiral raceway. The outer cylindrical surface of the ball screw is provided with a ball return channel which is sunken towards the center of the ball screw between two adjacent outer spiral raceways, the ball return channel and the outer spiral raceways of the ball screw are integrally designed, and the ball return channel and the outer spiral raceways form a circulating raceway; according to the internal circulation roller screw assembly, the ball screw outer spiral raceway and the ball return channel are integrally designed, the ball screw assembly is compact in structure and smooth in operation, uniformity and consistency of a ball screw and a ball nut are better, reliability and operation stability of the ball screw assembly are improved, and the service life of the ball screw assembly is prolonged. And the noise and vibration phenomena during high-speed operation of the ball screw pair are greatly reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to ball screw pair technical field, especially a nut drive type ball screw pair of hyperbolic tangent and algebraic sine coupling. BACKGROUND

[0002] Ball screw pair is a kind of rolling function component that can convert rotary motion into linear motion or linear motion into rotary motion, it has been widely used in industrial field due to its high transmission efficiency, high precision, small friction wear and other characteristics, and has become one of the key functional components in the industry fields such as numerical control machine tool, aerospace, automobile manufacturing, 3C electronics and medical equipment.

[0003] Ordinary screw pair is only matched with screw and nut, it relies on sliding friction, and has large friction coefficient and low transmission efficiency, so it is not suitable for application in occasions with high motion precision requirement and large load requirement, ball screw pair is generally used in such occasions, according to different ball circulation modes, ball screw pair can be divided into internal circulation type ball screw pair, plug tube type external circulation ball screw pair, spiral groove type external circulation ball screw pair and end cover type external circulation ball screw pair, wherein internal circulation type ball screw pair has the advantages of short ball circulation chain, flexible reverse, compact structure, good rigidity, reliable use, long service life and small matching outer diameter of ball nut, the commonly used internal circulation type ball screw pair adopts the structure that reverse device hole is opened in ball nut, ball return channel is designed on reverse device, and reverse device is embedded into reverse device hole of ball nut, but due to the existence of reverse device, ball screw pair vibrates violently and generates large noise during high-speed operation, which affects the running stability and reliability of ball screw pair, therefore, it is urgent to design spiral raceway and ball return channel in one piece in internal circulation ball screw pair.

[0004] The general use method of ball screw pair is to drive ball screw to rotate by servo control motor, so as to drive ball nut to move axially, which is called positive transmission, and this kind of ball screw pair is called positive type ball screw pair, the effective outer spiral raceway length of ball screw of positive type ball screw pair is greater than the sum of the length of effective inner spiral raceway of ball nut and effective stroke of ball screw pair, therefore, ball circulation device of ball screw pair needs to be arranged on inner spiral raceway of ball nut and move axially with ball nut, the above structural features make the outer diameter size of positive type ball screw pair relatively large, and it is difficult to realize micro and lightweight design under the condition of guaranteeing the load capacity, service life and precision of ball screw pair.

[0005] The reverse ball screw pair is driven by a servo motor to rotate the ball nut to drive the ball screw to move axially, which is called reverse transmission, also called ball nut driven ball screw pair. The effective inner spiral raceway length of the ball nut of the ball nut driven ball screw pair is greater than the sum of the effective outer spiral raceway length of the ball screw and the effective stroke of the ball screw pair, so the ball return channel of the ball screw pair can be arranged on the outer spiral raceway of the ball screw and move axially with the ball screw. However, the ball screw pair with the ball return channel arranged on the ball screw still has a mechanical structure of a ball stopper on the ball screw, which is fixed on the ball screw by a set screw, resulting in insufficient reliability and running stability of the ball screw pair.

[0006] As shown in the application No. 202410902557.8, the reverse ball screw pair has a ball stopper outside the reverse groove, the reverse groove and the inner side of the ball stopper form a reverse raceway that communicates with adjacent raceways, and the ball stopper is positioned in the groove by embedding the protrusion in the groove. Due to the presence of the ball stopper, the ball screw pair vibrates violently and generates loud noise during high-speed operation, which affects the running stability and reliability of the ball screw pair. Therefore, it is urgent to integrate the spiral raceway and the ball return channel in the internal circulation ball screw pair. Practical new type content

[0007] The utility model discloses to solve the shortcoming in the prior art, provide a ball nut driven internal circulation ball screw pair that ball return channel and ball screw outer spiral raceway are integrated design, it is small when high -speed operation vibration, low noise, can realize high DN value, with high reliability and long life etc.

[0008] The technical solution for realizing the utility model is as follows:

[0009] A nut driven ball screw pair coupled by hyperbolic tangent and algebraic sine, comprising a ball screw and a ball nut, an inner spiral raceway is arranged on the inner hole of the ball nut, an outer spiral raceway is arranged on the outer cylindrical surface of the ball screw, and the inner spiral raceway and the outer spiral raceway cooperate to form a spiral raceway; characterized in that the outer cylindrical surface of the ball screw is provided with a ball return channel recessed towards the center of the ball screw between two adjacent outer spiral raceways, the ball return channel and the outer spiral raceway of the ball screw are integrated design, and the ball return channel and the outer spiral raceway form a circulating raceway; a plurality of balls are arranged in the circulating raceway, when the ball nut rotates, the balls in the circulating raceway drive the ball screw to move axially relative to the ball nut, thereby realizing the ball nut driven ball screw pair.

[0010] Preferably, the return bead channel of the return bead curve is a "hyperbolic tangent and algebraic sine" coupling, the return bead curve is a spatial three-dimensional curve, and the return bead curve is obtained by the intersection of two cylindrical surfaces, which are Ω1 and Ω2; wherein the projection curve of the return bead curve in the xoy plane is the directrix of the Ω1 surface, which is a hyperbolic tangent curve; the projection curve of the return bead curve in the zox plane is the directrix of the Ω2 surface, which is a first algebraic sine curve; the function equations of the directrices of the cylindrical surfaces Ω1 and Ω2 are as follows:

[0011] The function equation of the directrix of the cylindrical surface Ω1 is: The function equation of the directrix of the cylindrical surface Ω2 is: y = -K x x sin(D w x);

[0012] Wherein, d is the ball pitch of the ball screw pair, h P is the lead, w D is the diameter of the steel ball, and θ is the lead angle.

[0013] Preferably, one side of the outer helical raceway of the ball screw is provided with a front limit spiral groove, and the other side is provided with a rear limit spiral groove; the spiral lines of the front limit spiral groove and the rear limit spiral groove are variable lead spiral lines, and the maximum lead value is still less than the lead angle of the ball screw pair.

[0014] Preferably, the parametric equation of the variable lead spiral line is:

[0015]

[0016] In the formula, t is time, ω is the angular velocity of circular motion, θ is the initial angle, and a and b are constants.

[0017] Preferably, the outer helical raceway of the ball screw is provided with a plurality of circulating raceways, the centers of the return bead channels of the plurality of circulating raceways are on the same spiral line, and the return bead channels on the circulating raceways are uniformly distributed in the circumferential direction of the ball screw.

[0018] Preferably, the number of the return bead channels is 3 to 6, and the return bead channels cooperate with the outer helical raceway of the ball screw to form 3-6 circulating raceways; the plurality of circulating raceways are uniformly distributed in the axial direction of the ball screw, and the return bead channels are uniformly arranged in the circumferential direction of the ball screw and are in a spiral shape.

[0019] Preferably, the front end of the outer cylindrical surface of the ball nut is provided with a pin hole, the rear end of the outer cylindrical surface of the ball nut is provided with a screw hole, and the lower side of the screw hole is provided with a counterbore.

[0020] Preferably, the pin hole of the ball nut is provided with an elastic cylindrical pin, and the screw hole of the ball nut is provided with a cross slot head screw, and the cross slot head screw is sunk in the counterbore of the ball nut.

[0021] Preferably, the outer circle of one end of the ball nut is provided with external threads, and the outer circle of the ball nut is provided with a positioning groove.

[0022] Preferably, the protruding shaft of the ball screw is provided with a mounting through hole, and the front view of the mounting through hole is circular, and the cross section is elliptical.

[0023] Compared with the prior art, the utility model has the following remarkable advantages:

[0024] (1) The utility model discloses a ball screw outer spiral raceway and ball return channel integrated design's internal circulation roller screw pair, and the ball screw pair structure is compact, and the operation is smooth, and because the existence of reverser part is avoided, the uniformity and consistency of the ball screw and the ball nut are better, and the reliability and operation stability of the ball screw pair are improved, and the noise and vibration phenomenon of the ball screw pair high-speed operation are greatly reduced.

[0025] (2) The ball return curve of the ball return channel adopts the intersection of the cylindrical surface with the hyperbolic tangent function and the first algebraic sine function as the guide line, stress concentration points are eliminated, and vibration and noise under high-speed working conditions are solved from the root.

[0026] (3) The ball nut driving type internal circulation ball screw pair of the utility model, the helical limiting screw grooves are processed on the two sides of the outer cylindrical surface of the ball screw, in the process that the ball nut rotates and drives the ball screw to carry out axial reciprocating linear motion, when the ball screw moves to the front end limit position, the end face of the front limiting screw groove of the ball screw will line contact the side face of the elastic cylindrical pin in the pin hole of the ball nut, or the end face of the rear limiting screw groove of the ball screw will first contact the thread side face of the cross slot head screw in the screw hole of the ball nut, thereby realizing the front and rear mechanical limiting function in the operation of the ball screw pair. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the description below only show some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0028] Figure 1 The structure diagram of the present application.

[0029] Figure 2 The structure diagram of the ball screw in the present application.

[0030] Figure 3 The structure diagram of the ball nut in the present application.

[0031] Figure 4 The structure diagram of a row of balls in the present application.

[0032] Figure 5 The structure diagram of the ball return channel in the present application.

[0033] In the figure: 1-ball screw; 11-mounting through hole; 12-front limit spiral groove; 13-rear limit spiral groove; 14-outer spiral raceway; 15-ball return channel; 16-outer cylindrical surface; 17-protruding shaft; 2-ball nut; 21-pin hole; 22-counterbore; 23-screw hole; 24-inner spiral raceway; 26-outer thread; 27-positioning groove; 3-elastic cylindrical pin; 4-cross slot head screw; 5-ball. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0035] Embodiment 1:

[0036] As Figure 1 , Figure 2 and Figure 3As shown, the utility model discloses a nut drive type ball screw pair coupled with hyperbolic tangent and algebraic sine, including ball screw 1, ball nut 2, elastic cylindrical pin 3, cross slot disc head screw 4 and ball 5, the outer cylindrical surface 16 of ball screw 1 is provided with outer spiral raceway 14, the inner hole of ball nut 2 is provided with the inner spiral raceway 24 matched with the outer spiral raceway 14 of ball screw 1, the outer cylindrical surface 16 of ball screw 1 is provided with return ball channel 15, return ball channel 15 is located between the adjacent outer spiral raceway 14 of ball screw 1 and recesses to the center of ball screw 1, return ball channel 15 is integrative design with outer spiral raceway 14, and return ball channel 15 and outer spiral raceway 14 are connected to form circulating raceway, a plurality of balls 5 are arranged in circulating raceway, form ball movement chain, ball movement chain transmits force and movement, ball nut 2 rotates, and ball screw 1 is driven to make axial linear motion relative to ball nut 2 through the ball 5 of circulating raceway, the installation through-hole 11 is formed on the extension shaft 17 of ball screw 1, the front view of installation through-hole 11 is circular, and the section is oval, and installation through-hole 11 can be installed with external parts.

[0037] The ball circulating mode of the inner circulating ball screw pair in the embodiment is inconsistent with the prior art, and the prior art mostly has a reverser structure, which is installed on the ball screw 1 or the ball nut 2 by means of screws or cooperation, and has the defects of stress concentration and easy wear at the position thereof. In the embodiment, the return ball channel 15 of the ball 5 is directly machined on the ball screw 1 to form an integrated design. Specifically, the ball 5 performs spiral movement along the outer spiral raceway 14 of the ball screw 1. Without any limitation, the ball 5 will directly roll out and fall from one end of the ball screw 1, which requires the limitation of the return ball channel 15 to force the ball 5 to return to the starting position. According to the different forms of the return ball channel 15, different types of ball screw pairs are formed. After the ball 5 moves along the outer spiral raceway 14 of the ball screw for more than half of a spiral, the movement trajectory follows the guide of the return ball channel 15, crosses the inner spiral raceway 24 of the ball nut 2, and finally returns to the starting position of the circulating raceway. The ball 5 moves back and forth and circulates in this way. In the embodiment, the number of the return ball channels 15 is four, which cooperates with the outer spiral raceway 14 of the ball screw 1 to form four circulating raceways. The four circulating raceways are uniformly distributed in the axial direction of the ball screw 1, and the return ball channels 15 are uniformly arranged in the circumferential direction of the ball screw 1 and in a spiral shape.

[0038] The return bead channel 15 in the embodiment is processed according to the characteristics of the return bead curve, which is a three-dimensional curve in space and can be obtained by the intersection of two cylindrical surfaces, namely Ω1 and Ω2. The projection curve of the return bead curve in the xoy plane is the directrix of the Ω1 surface, which is a hyperbolic tangent curve; the projection curve of the return bead curve in the zox plane is the directrix of the Ω2 surface, which is a first algebraic sine curve. The directrix equations of the cylindrical surfaces Ω1 and Ω2 are as follows:

[0039] The function equation of the directrix of the cylindrical surface Ω1 is as follows:

[0040] The function equation of the directrix of the cylindrical surface Ω2 is as follows: y = -K x x sin (D w x);

[0041] Wherein: d is the pitch of the ball screw pair, h P is the lead, w D is the diameter of the steel ball, and D is the lead angle.

[0042] In the embodiment, the outer spiral raceway 14 of the ball screw is provided with a front limit position spiral groove 12 on one side and a rear limit position spiral groove 13 on the other side; the spiral lines of the front limit position spiral groove 12 and the rear limit position spiral groove 13 are variable pitch spiral lines, and the maximum lead value is still less than the lead angle of the ball screw pair. The parametric equation of the variable pitch spiral line is as follows:

[0043]

[0044] In the formula, t is time, ω is the angular velocity of circular motion, θ is the initial angle, and a and b are constant.

[0045] In the process of rotating the ball nut to drive the ball screw to move axially and linearly, when the ball screw moves to the front end limit position, the end surface of the front limit position spiral groove of the ball screw will line contact the side surface of the elastic cylindrical pin located in the ball nut pin hole, or the end surface of the rear limit position spiral groove of the ball screw will first contact the thread side surface of the cross slot disc head screw located in the ball nut screw hole, thereby realizing the front and rear mechanical limiting function in the running of the ball screw pair.

[0046] The inner hole of the ball nut 2 is provided with an inner spiral raceway 24 in the embodiment, the inner spiral raceway 24 and the outer spiral raceway 14 and the plurality of ball return channels 15 of the ball screw 1 jointly constitute a plurality of circulating raceways of the balls 5. The front end of the outer cylindrical surface of the ball nut 2 is provided with a pin hole 21, the rear end is provided with a counterbore 22, a screw hole 23 is arranged at the position corresponding to the counterbore 22; the elastic cylindrical pin 3 can be installed in the pin hole 21 of the ball nut 2, so that the elastic cylindrical pin 3 does not hinder the installation and use of the outer thread 26, the cross slot head screw 4 is screwed in the screw hole 23 of the ball nut 2, the cross slot head screw 4 is sunk in the counterbore 22 of the ball nut 2, so that the nut of the cross slot head screw 4 does not protrude on the outer cylindrical surface of the ball nut 2, which is helpful for the cooperation of the ball nut 2 and external parts; two blocks are cut off on the maximum outer circle of the ball nut 2, forming a positioning groove 27, which is convenient for the machining and manufacturing of the ball nut 2; the outer cylindrical surface of the ball nut 2 is provided with an outer thread 26, so that the nut can be installed and cooperated with external parts.

[0047] In conclusion, the utility model adopts the inner circulating roller screw pair of the ball screw outer spiral raceway and ball return channel integrated design, the ball screw pair structure is compact, the operation is smooth, because no reverser part exists, the uniformity and consistency of the ball screw and the ball nut are better, and meanwhile the reliability and operation stability of the ball screw pair are improved, and the noise and vibration phenomenon of the ball screw pair during high-speed operation is greatly reduced.

[0048] In the utility model, the ball return curve of the ball return channel is formed by the intersection of the cylindrical surface with the tangent function of hyperbolic tangent and the algebraic sine function as the guide line, which eliminates the stress concentration point and solves the vibration and noise under high-speed working condition from the root. The ball return curve is coupled by the function of hyperbolic tangent-algebraic sine, which unifies the contradictory requirements of ball kinematics optimization, dynamics noise reduction and contact mechanics strengthening in a single spatial curve, realizes the deep collaborative innovation of mechanical structure-mathematical model, and realizes the precise control of the ball motion characteristics through function coupling. The value is not only to eliminate the reverser, but also to create a new paradigm of "function driven design" for precision transmission components. It provides a new technical route for the development of high DN value, ultra-precision and long-life ball screw pairs.

[0049] In the utility model, the ball nut driving type inner circulating ball screw pair, the outer cylindrical surface of the ball screw is provided with spiral limiting spiral grooves on both sides, in the process that the ball nut rotates and drives the ball screw to move axially and reciprocally, when the ball screw moves to the front limit position, the end face of the front limiting spiral groove of the ball screw will first contact the side face of the elastic cylindrical pin in the pin hole of the ball nut, or the end face of the rear limiting spiral groove of the ball screw will first contact the thread side of the cross slot head screw in the screw hole of the ball nut, thereby realizing the front and rear mechanical limiting function during the operation of the ball screw pair.

[0050] It should be pointed out finally that: the above only for the preferred embodiments of the utility model have, and do not limit the utility model, although the utility model is described in detail with reference to the foregoing embodiments, for the person skilled in the art, it still can modify the technical scheme recorded in the foregoing each embodiment, or equivalent replacement to part of technical features. Any modification, equivalent replacement, improvement etc. that is made within the spirit and principle of the utility model, should be included in the protection scope of the utility model.

Claims

1. A nut-driving ball screw pair of "tanh and algebraic sine" coupling, comprising a ball screw (1) and a ball nut (2), an inner spiral raceway (24) is arranged on the inner hole of the ball nut (2), an outer spiral raceway (14) is arranged on the outer cylindrical surface (16) of the ball screw (1), and the inner spiral raceway (24) and the outer spiral raceway (14) cooperate to form a spiral raceway; characterized in that, The outer cylindrical surface (16) of the ball screw (1) is provided with a ball returning channel (15) recessed to the center of the ball screw between two adjacent outer spiral raceways (14), the ball returning channel (15) is designed in an integrated manner with the outer spiral raceway (14) of the ball screw (1), the ball returning channel (15) and the outer spiral raceway (14) form a circulating raceway; a plurality of balls (5) are arranged in the circulating raceway, when the ball nut (2) rotates, the ball screw (1) is driven to move axially relative to the ball nut (2) through the balls (5) in the circulating raceway, so that the ball screw pair driven by the ball nut is realized.

2. The nut drive type ball screw pair coupled with "tangent hyperbolic and algebraic sine" according to claim 1, characterized in that, The ball returning curve of the ball returning channel (15) is coupled by "hyperbolic tangent and algebraic sine", the ball returning curve is a three-dimensional space curve, and the ball returning curve is obtained by the intersection of two cylindrical surfaces, the two cylindrical surfaces are denoted as Ω1 and Ω2; wherein the projection curve of the ball returning curve in the xoy plane is the directrix of the Ω1 surface, which is a hyperbolic tangent curve; the projection curve of the ball returning curve in the zox plane is the directrix of the Ω2 surface, which is a first-order algebraic sine curve; the directrix equations of the cylindrical surfaces Ω1 and Ω2 are as follows: The functional equation of the directrix of the cylindrical surface curve Ω1 is: The function equation of the directrix of the cylindrical curved surface Ω2 is: y = -Kx x sin(D w x); wherein, d is the ball pitch in the ball screw pair, P h is the lead, w is the ball diameter, is the lead angle.

3. The Nut Drive Ball Screw Assembly with Coupling of Hyperbolic Tangent and Algebraic Sine as claimed in claim 1, wherein, The outer spiral raceway (14) of the ball screw (1) is provided with a front limiting spiral groove (12) on one side and a rear limiting spiral groove (13) on the other side; the spiral lines of the front limiting spiral groove (12) and the rear limiting spiral groove (13) are variable lead spiral lines, and the maximum lead value is still smaller than the lead angle of the ball screw pair.

4. The nut drive ball screw pair of claim 3, wherein The parameter equation of the variable lead spiral line is as follows: In the formula, t is time, ω is the angular velocity of circular motion, θ is the initial angle, and a and b are constant.

5. The Nut Drive Ball Screw Assembly with Coupling of Hyperbolic Tangent and Algebraic Sine as claimed in claim 1, wherein, The outer spiral raceway (14) of the ball screw (1) is provided with a plurality of circulating raceways, the centers of the ball returning channels (15) of the plurality of circulating raceways are on the same spiral line, and the ball returning channels (15) on the circulating raceways are uniformly distributed in the circumferential direction of the ball screw (1).

6. The nut drive ball screw pair of the coupled "tanh and algebraic sine" according to claim 5, characterized in that, The number of the ball returning channels (15) is 3 to 6, and the ball returning channels (15) and the outer spiral raceway (14) of the ball screw (1) form 3-6 circulating raceways; the plurality of circulating raceways are uniformly distributed in the axial direction of the ball screw (1), and the ball returning channels (15) are uniformly arranged in the circumferential direction of the ball screw (1) and are in a spiral shape.

7. The Nut Drive Ball Screw Assembly with Coupling of Hyperbolic Tangent and Algebraic Sine as claimed in claim 1, wherein, The front end of the outer cylindrical surface of the ball nut (2) is provided with a pin hole (21), the rear end of the outer cylindrical surface of the ball nut (2) is provided with a screw hole (23), and the lower portion of the screw hole (23) is provided with a counterbore (22).

8. The nut drive ball screw pair of claim 7, wherein The pin hole (21) of the ball nut (2) is provided with an elastic cylindrical pin (3), and the screw hole (23) of the ball nut (2) is provided with a cross slot head screw (4), and the cross slot head screw (4) is sunk in the counterbore (22) of the ball nut (2).

9. The Nut Drive Ball Screw Assembly of claim 1, wherein, One end of the outer circle of the ball nut (2) is provided with an external thread (26), and the outer circle of the ball nut (2) is provided with a positioning groove (27).

10. The Nut Drive Ball Screw Assembly of claim 1, wherein, The protruding shaft (17) of the ball screw (1) is provided with a mounting through hole (11), the front view of the mounting through hole (11) is circular, and the cross section is elliptical.

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