Ball screw pair

Abstract

The present invention discloses a ball screw pair, comprising a screw shaft, a screw nut, balls and a ball deflector. The helical teeth of the screw shaft and the screw nut are arranged in a cross manner in the axial direction, so that a spiral channel is formed on both sides of the helical teeth respectively, and the two spiral channels are both load travel channels and load-free return channels of the balls; spiral grooves are provided on both side surfaces of the helical teeth of the screw shaft and the screw nut as spiral motion raceway surfaces of the balls, and the contact angle α between the balls and the raceway surfaces in the spiral channel is greater than 45°; a ball deflector is provided at each end of the helical teeth of the screw nut, so that the balls can move from any side of the helical teeth of the screw nut to the other side, so as to form a complete ball circulation channel; when the ball screw pair has two or more ball circulation channels, the helical teeth of the screw nut are divided into two or more sections, and each section of the helical teeth and the deflectors at both ends thereof can form a complete ball circulation channel.

Description

Technical field:

[0001] The invention belongs to the technical field of mechanical transmission, and relates to a ball screw pair using balls as rolling bodies. Background technology:

[0002] The ball screw pair is a spiral transmission mechanism with balls as rolling elements, in which multiple balls are located between the screw shaft and the screw nut to bear and transmit the load. Compared with the sliding screw pair, the ball screw pair has the advantages of high transmission efficiency and high transmission accuracy, so the ball screw pair is widely used in machine tools and other fields.

[0003] In the ball screw pair of the prior art, the outer cylindrical surface of the screw shaft and the inner cylindrical surface of the screw nut both have a spiral groove with a V-shaped cross section, and these two spiral grooves form a ball spiral motion channel with a quadrilateral cross section in a mouth-to-mouth manner. In the normal section of the spiral channel, the angle between the line connecting the ball center and the raceway contact point and the vertical line of the spiral groove rotation axis is called the contact angle α. Generally, as the contact angle α increases, the load-bearing capacity and axial stiffness of the ball screw pair become greater, and the transmission efficiency becomes higher. However, in the prior art, the contact angle α of the ball screw pair is generally not greater than 45°, thereby limiting the improvement of the load-bearing capacity, axial stiffness and transmission efficiency of the ball screw pair. Summary of the invention:

[0004] The object of the present invention is to provide a ball screw pair with a contact angle α greater than 45°, thereby improving the bearing capacity, axial rigidity and transmission efficiency of the ball screw pair.

[0005] The technical solution of the present invention to solve the technical problem is:

[0006] A ball screw pair includes a screw shaft, a screw nut, balls and a ball reverser. The outer cylindrical surface of the screw shaft and the inner cylindrical surface of the screw nut are both provided with helical teeth, and the helical teeth of the screw shaft and the helical teeth of the screw nut are arranged in a cross manner in the axial direction, that is, the helical teeth of the screw shaft are located between the tooth grooves of the helical teeth of the screw nut, and the helical teeth of the screw nut are located between the tooth grooves of the helical teeth of the screw shaft; both side surfaces of the helical teeth of the screw shaft and the two side surfaces of the helical teeth of the screw nut are provided with spiral grooves, and the spiral direction and lead of the spiral grooves are the same as those of the spiral teeth; the spiral grooves on the side surfaces of the spiral teeth are used as the spiral motion raceway surface of the balls, and the two spiral grooves on the side surfaces of the spiral teeth of the screw shaft and the two spiral grooves on the side surfaces of the spiral teeth of the screw nut are aligned with each other. The spiral grooves form two spiral ball motion channels, which are respectively recorded as ball spiral channel one and ball spiral channel two; there is a ball reverser at each end of the screw nut spiral teeth, and the ball reverser forms a ball reverse channel at each end of the screw nut spiral teeth, which are recorded as ball reverse channel one and ball reverse channel two. The balls can move from either side of the nut spiral teeth to the other side through these two reverse channels; the ball spiral channel one, the ball spiral channel two, the ball reverse channel one and the ball reverse channel two together form a complete ball circulation channel, and multiple balls form a motion circulation chain in a complete ball circulation channel.

[0007] The ball spiral channel one and the ball spiral channel two are both the load travel channel of the ball and the no-load return channel of the ball; when the ball screw pair is subjected to axial load, one channel of the ball spiral channel one and the channel two through which the ball transmits the axial load is the load travel channel of the ball, and the other channel simultaneously serves as the no-load return channel of the ball; when the axial load is reversed, the original ball load travel channel is transformed into the ball no-load return channel, and at the same time, the original ball no-load return channel is transformed into the ball load travel channel; an axial gap is provided between the ball and the spiral raceway surface of the screw shaft or the spiral raceway surface of the screw nut, and the size of the axial gap can allow the ball to move smoothly in its no-load return channel.

[0008] In the ball spiral channel one and the ball spiral channel two, the contact points of the balls with the spiral raceway surfaces of the screw shaft and the spiral raceway surfaces of the screw nut when transmitting axial loads are both located within the normal sections of the spiral channels, and within the normal sections of the two spiral channels, the angles between the lines connecting the centers of the balls and the raceway contact points and the perpendiculars to the axes of rotation of the spiral channels are in opposite directions, that is, the directions of the contact angles α are in opposite directions.

[0009] The normal cross-sectional profile of the spiral groove on the side surface of the spiral tooth of the screw shaft includes a single arc shape and a double arc shape. The normal cross-sectional profile of the single arc groove is mainly composed of one arc segment, and the normal cross-sectional profile of the double arc groove is mainly composed of two arc segments; similarly, the normal cross-sectional profile of the spiral groove on the side surface of the spiral tooth of the screw nut also includes a single arc shape and a double arc shape; the groove on the side surface of the spiral tooth of the screw nut has a transitional curved surface at both ends of the spiral tooth of the screw nut.

[0010] The ball reverse guiding action surfaces on the ball deflector are all located between the tooth grooves of the helical teeth of the screw shaft and face the end faces of the helical teeth of the screw nut; when only one side of the ball deflector has a ball reverse guiding action surface, it is recorded as a single reverse face ball deflector; when both sides of the ball deflector have ball reverse guiding action surfaces, it is recorded as a double reverse face ball deflector; the two reverse guiding action surfaces on the double reverse face ball deflector respectively face the end faces of the helical teeth of the screw nut on both sides of the deflector; the upper and lower end faces of the ball deflector located in the helical tooth grooves of the screw shaft are both spiral surfaces, and their leads are the same as the lead of the helical teeth of the screw shaft, and there are geometric gaps between these two end faces and the adjacent side faces of the helical teeth of the screw shaft.

[0011] The ball screw pair may have two or more complete ball circulation channels. When the ball screw pair has two or more complete ball circulation channels, the screw nut helical teeth are divided into two or more discontinuous sections in the spiral direction, and both ends of each section of the screw nut helical teeth have transitional curved surfaces; there is a gap between any two adjacent end faces of the screw nut helical teeth, and a double-reverse-face ball deflector is arranged in the gap, and the ball spiral channel 1 and the ball spiral channel 2 are both divided into two or more sections by the double-reverse-face ball deflector; each section of the screw nut helical teeth and the ball deflectors at both ends form a complete ball circulation channel, and multiple balls can form a motion circulation chain in each circulation channel.

[0012] The ball screw pair can adopt a floating ball deflector. The floating ball deflector means that the ball reverse guide surface on the ball deflector can float along the spiral tooth groove of the screw shaft when impacted by the ball, and has stiffness and damping that meet the use requirements in the floating direction; when the floating ball deflector has only one ball reverse guide surface, it is recorded as a single reverse surface floating ball deflector; when it has two reverse guide surfaces, it is recorded as a double reverse surface floating ball deflector; when the ball screw pair adopts a floating ball deflector, the single reverse surface ball deflector and the double reverse surface ball deflector are replaced by a single reverse surface floating ball deflector and a double reverse surface floating ball deflector respectively.

[0013] The single-reverse floating ball reverser is mainly composed of a back plate, a floating block, an adjustment block, a fixed block, an elastic element, a wedge key and a cover plate; the back plate is fixed on the lead screw nut, and a guide groove is provided on the inner side of the back plate, and the guide track of the guide groove is a spiral line, and its lead is the same as the lead of the spiral tooth groove of the lead screw shaft; the floating block and the adjustment block are both provided with guide surfaces, and the guide surfaces can make the floating block and the adjustment block move along the guide groove on the back plate; the fixed block is fixed on the lead screw nut, the wedge key is located between the fixed block and the adjustment block, and the elastic element is located between the adjustment block and the floating block, and the position of the wedge key is adjusted to make the adjustment block The block moves along the guide groove on the back plate, thereby changing the distance between the adjustment block and the floating block and the deformation of the elastic element; the floating block is provided with a ball reverse guiding surface, and the elastic element applies a pre-tightening force to the floating block after being deformed by pressure, so that the floating block can float along the guide groove of the back plate when impacted by the ball; the upper and lower end faces of the floating block and the upper and lower end faces of the adjustment block are all spiral surfaces, and the lead of the spiral surfaces is the same as the lead of the spiral teeth of the screw shaft; the cover plate is located on the outer side of the large end of the wedge key, and an adjusting gasket is provided between the cover plate and the fixed block, and the position of the wedge key is adjusted by changing the thickness of the adjusting gasket.

[0014] The double-reverse-surface floating ball reverser is mainly composed of a back plate, a floating block 1, a floating block 2, a wedge key, an elastic element and an adjusting gasket; the inner side of the back plate is provided with a guide groove, the guide track of the guide groove is a spiral line, and the lead of the spiral line is the same as the lead of the spiral teeth of the screw shaft; the floating block 1 and the floating block 2 are both provided with floating guide surfaces, and the floating guide surfaces can enable the floating blocks to move along the guide grooves on the back plate; the floating block 1 and the floating block 2 are respectively provided with a ball reverse guide channel, and the two ball reverse guide channels respectively face the end faces of the spiral teeth of the screw nut on both sides of the reverser; the upper and lower end faces of the floating block 1 and the floating block 2 are both spiral surfaces, and the leads of the spiral surfaces are the same as the leads of the spiral teeth of the screw shaft; the elasticity of the elastic element The action part and the wedge-shaped part of the wedge-shaped key are both located between the floating block one and the floating block two, and the deformation of the elastic element is adjusted by the wedge-shaped key. After the elastic element is deformed by pressure, a preload is applied to the floating block. A through hole is provided in the middle of the back plate, and the elastic action part of the elastic element and the wedge-shaped part of the wedge-shaped key are both inserted into the inner side of the back plate from the through hole in the middle of the back plate. The fixed ends of the elastic element and the wedge-shaped key are both located on the outer side of the back plate, and the adjustment gasket is located between the fixed ends of the elastic element and the wedge-shaped key. The relative position between the wedge-shaped key and the elastic element is adjusted by changing the thickness of the adjustment gasket, so that the deformation of the elastic element and the size of the preload can be changed. The wedge-shaped key, the elastic element and the adjustment gasket are all fixed on the back plate of the double-reverse-surface floating ball reverser.

[0015] In the ball circulation channel of the ball screw pair, a separator can be arranged between adjacent balls, and the separator can separate adjacent balls; the two side surfaces of the ball separator in contact with the balls are both concave spherical surfaces, and the radii of the two concave spherical surfaces are both larger than the ball radius.

[0016] The screw shaft adopts double screw nut pre-tightening and adjustment, and the double screw nut pre-tightening of the ball screw pair includes double nut tooth difference pre-tightening, double nut thread pre-tightening, and double nut gasket pre-tightening.

[0017] Beneficial effects of the present invention:

[0018] 1. The ball screw pair of the present invention arranges the screw shaft helical teeth and the screw nut helical teeth in a cross manner in the axial direction, and spiral grooves are provided on both side surfaces of the screw shaft helical teeth and the screw nut helical teeth as the spiral motion raceway surfaces of the balls, thereby forming two ball spiral motion channels on both sides of the spiral teeth; multiple balls move in these two spiral channels and transmit axial loads; compared with the ball screw pair of the prior art, this structure can make the angle between the line connecting the ball center and the raceway contact point and the perpendicular line of the spiral channel rotation axis greater than 45°, thereby significantly increasing the contact angle α.

[0019] 2. In the normal sections of spiral channel 1 and spiral channel 2 of the ball screw pair described in the present invention, because the angles between the line connecting the ball center and the raceway contact point and the perpendicular line of the spiral channel rotation axis are in opposite directions, that is, the directions of the contact angles α are opposite, the balls in these two channels can be used to transmit axial loads in opposite directions respectively.

[0020] 3. By arranging a ball reverser at both ends of the screw nut spiral teeth, the ball spiral channels on both sides of the screw nut spiral teeth are connected at both ends of the screw nut spiral teeth, thereby forming a complete ball circulation channel around the spiral teeth of the screw nut. In a complete ball circulation channel, multiple balls form a motion circulation chain. When the ball screw pair is subjected to axial load, one of the spiral channels located on both sides of the screw shaft and the screw nut spiral teeth serves as the load travel channel of the ball, and the other serves as the no-load return channel of the ball at the same time. When the axial load is reversed, the original ball load travel channel is transformed into the ball no-load return channel, and the original ball no-load return channel is transformed into the ball load travel channel. Therefore, these two spiral channels are both the load travel channel of the ball and the no-load return channel of the ball. When any one of them serves as the load travel channel of the ball, the other serves as the no-load return channel of the ball at the same time, so there is no need to design another ball return channel. The axial clearance between the ball and the screw shaft or the screw nut allows the ball to move smoothly in its unloaded return channel, so that the ball can smoothly return to the starting end of its loaded travel channel.

[0021] 4. The ball spiral motion raceway surface on the side surface of the helical teeth of the screw nut described in the present invention has transitional curved surfaces at both ends thereof, thereby improving the smoothness of the ball movement when it reverses at both ends of the helical teeth of the screw nut.

[0022] 5. The reverse guiding surfaces on the ball reverser described in the present invention are located between the tooth grooves of the helical teeth of the screw shaft and at both ends of the helical teeth of the screw nut, so the ball can move from either side of the helical teeth of the screw nut to the other side at both ends of the helical teeth of the screw nut; and because the spiral channels on both sides of the helical teeth of the screw nut are the load travel channel and the no-load return channel of the ball, the ball does not need to cross the top of the helical teeth of the screw shaft, nor does it need to leave the tooth grooves of the helical teeth of the screw shaft during the reverse and return process.

[0023] 6. The upper and lower end faces of the ball deflector located in the spiral tooth groove of the screw shaft are both spiral surfaces, and there are geometric gaps between these two end faces and the adjacent spiral tooth surfaces of the screw shaft, thereby avoiding geometric interference between the ball deflector and the spiral teeth of the screw shaft.

[0024] 7. The ball screw pair of the present invention may have two or more complete ball circulation channels. When the ball screw pair has two or more complete ball circulation channels, the screw nut helical teeth are divided into two or more sections in the spiral direction, and there is a gap between any two adjacent sections of the screw nut helical teeth, and a double reverse surface ball deflector is arranged in the gap. Because the double reverse surface ball deflector simultaneously divides the ball spiral channel 1 and the ball spiral channel 2 into two ends or multiple sections, and there are ball reverse guiding surfaces on both sides of the double reverse surface ball deflector, each section of the screw nut helical teeth and the ball deflectors at both ends form a complete ball circulation channel. Because a ball circulation chain can be formed in each circulation channel, the ball screw pair may have two or more ball circulation chains. When the ball screw pair is provided with two or more ball circulation chains, the length of a single ball circulation chain can be shortened, which is conducive to reducing the movement resistance of the ball in the circulation channel.

[0025] 8. When the ball screw pair of the present invention adopts the floating ball reverser, the impact and vibration of the ball on the reverser during the reversal process can be reduced.

[0026] 9. The floating block of the single-reverse floating ball reverser described in the present invention can move along the guide groove on the inner side of the back plate. Because the back plate is fixed relative to the screw nut, and the adjustment block is usually fixed relative to the back plate, and there is an elastic element support between the floating block and the adjustment block, the floating block can float along the guide groove on the inner side of the back plate when impacted by the ball, which can reduce the vibration caused by the ball impacting the floating block; because the guide trajectory of the guide groove on the inner side of the back plate is a spiral line, and its lead is the same as the lead of the spiral tooth groove of the screw shaft, the moving trajectory of the floating block is also a spiral line, and its lead is also the same as the lead of the spiral tooth groove of the screw shaft. Because the upper and lower end faces of the floating block are both spiral surfaces, and the leads of these two spiral end faces are the same as the lead of the spiral tooth groove of the screw shaft, the floating block will not have geometric interference with the spiral tooth surface of the screw shaft during the floating process; the distance between the floating block and the adjustment block and the compression deformation of the elastic element can be adjusted by the wedge key, so that the size of the floating block preload can be adjusted. In addition, a damping element may be arranged between the floating block and the adjusting block of the single-reverse surface floating ball deflector, so as to further reduce the vibration caused by the impact of the ball.

[0027] 10. The two floating blocks of the double reverse surface floating ball deflector of the present invention can both move along the guide groove on the inner side of the back plate. Because there is an elastic element support between the two floating blocks, the two floating blocks can both float along the guide groove on the inner side of the back plate when impacted by the ball, thereby reducing the vibration caused by the impact of the ball. Because the guide track of the guide groove on the inner side of the back plate is a spiral line, and its lead is the same as the lead of the spiral tooth groove of the screw shaft, the floating track of the two floating blocks is also a spiral line, and its lead is the same as the lead of the spiral tooth groove of the screw shaft; and because the upper and lower end surfaces of the floating block are both spiral surfaces, and its lead is also the same as the lead of the spiral tooth groove of the screw shaft, the two floating blocks will not have geometric interference with the spiral teeth of the screw shaft during the floating process. The deformation of the elastic element can be changed by the wedge key, so that the preload of the two floating blocks can be adjusted. In addition, a damping element can also be set between the two floating blocks of the double reverse surface floating ball deflector, which can further reduce the vibration caused by the impact of the ball.

[0028] 11. In the ball circulation channel of the ball screw pair described in the present invention, a separator is arranged between adjacent balls to avoid contact or collision between the balls, thereby helping to reduce vibration and noise. The two sides of the ball separator that contact the balls are both concave spherical surfaces, and the radius of the concave spherical surface is greater than the radius of the balls, so that the balls can be tangentially contacted with the side of the separator, thereby helping to reduce the friction between the two. Description of the drawings:

[0029] Figure 1It is a cross-sectional view of the internal structure of the ball screw pair provided by the present invention.

[0030] Figure 2 It is a structural schematic diagram of the helical teeth of the screw shaft of the ball screw pair provided by the present invention.

[0031] Figure 3 It is a structural schematic diagram of the helical teeth of the screw nut of the ball screw pair provided by the present invention.

[0032] Figure 4 It is a schematic diagram of the relative position relationship between the balls of the ball screw pair provided by the present invention and the helical teeth of the screw shaft and the helical teeth of the screw nut in the spiral channel.

[0033] Figure 5 and Figure 6 It is a schematic diagram of the positional relationship between the balls of the ball screw pair provided by the present invention at both ends of the helical teeth of the screw nut and the single-reverse surface ball reverser.

[0034] Figure 7 It is a schematic diagram of a ball circulating motion chain of the ball screw pair provided by the present invention.

[0035] Figure 8 and Fig. 9 It is a schematic structural diagram of the vicinity of both ends of the helical teeth of the screw nut of the ball screw pair provided by the present invention.

[0036] Fig.10 and Fig.11 It is a structural view of a single-reverse-face ball reverser of a ball screw pair provided by the present invention.

[0037] Fig.12 It is a schematic diagram of the relative position relationship between the screw shaft of the ball screw pair provided by the present invention and the single-reverse surface ball reverser.

[0038] Fig.13 It is a schematic diagram of the maximum axial clearance between the ball and the screw shaft or the screw nut in the spiral channel of the ball screw pair provided by the present invention.

[0039] Fig.14 and Fig.15 : is a schematic diagram of the normal cross-sectional profile of the groove on the side surface of the helical teeth of the screw shaft and the screw nut of the ball screw pair provided by the present invention, wherein: Fig.14 It is a schematic diagram of the cross-sectional profile of a single arc channel. Fig.15 It is a schematic diagram of the cross-sectional profile of a double arc channel.

[0040] Fig.16 It is a schematic diagram of the segmented structure of the helical teeth of the screw nut when the ball screw pair provided by the present invention has two complete ball circulation channels.

[0041] Fig.17 The figure is an outer structural view of the screw nut when the ball screw pair provided by the present invention has two complete ball circulation channels.

[0042] Fig.18 The structure of the double reverse surface ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0043] Fig.19 The structure of the double reverse surface ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0044] Fig. 20 and Fig.21 It is a schematic diagram of the positional relationship between the screw nut helical teeth, balls and a reverser when the ball screw pair provided by the present invention has two ball circulation chains, wherein the two ball circulation chains are respectively located on both sides of the double-reverse-face ball reverser.

[0045] Fig. 22 It is a schematic diagram of the inner structure of the single-reverse floating ball reverser provided by the present invention.

[0046] Fig.23 The figure is a schematic diagram of the inner structure of the single-reverse floating ball reverser provided by the present invention after the floating block is removed.

[0047] Fig.24 It is a schematic diagram of the back plate structure of the single-reverse floating ball reverser provided by the present invention.

[0048] Fig.25a The structure of the floating block of the single-reverse floating ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0049] Fig.25b The structure of the floating block of the single-reverse floating ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0050] Fig.26a The structural diagram of the adjustment block of the single-reverse floating ball reverser provided by the present invention is Figure 1 .

[0051] Figure 26b The structural diagram of the adjustment block of the single-reverse floating ball reverser provided by the present invention is Figure 2 .

[0052] Fig.26c The structural diagram of the adjustment block of the single-reverse floating ball reverser provided by the present invention is Figure 3 .

[0053] Fig. 27 It is a structural schematic diagram of the plate spring of the single-reverse floating ball reverser provided by the present invention.

[0054] Fig.28 The utility model is a schematic diagram of the assembly relationship between the back plate, the wedge key and the adjustment block of the single-reverse surface floating ball reverser provided by the present invention.

[0055] Fig.29 The utility model is a schematic diagram of the assembly relationship between the back plate, the wedge key and the fixed block of the single-reverse surface floating ball reverser provided by the present invention.

[0056] Fig.30 The figure is a schematic diagram of the assembly relationship between the back plate, the fixing block and the cover plate of the single-reverse floating ball reverser provided by the present invention.

[0057] Fig.31a The structure of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0058] Fig.31b The structure of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0059] Fig.32 It is a schematic diagram of the inner structure of the double-reverse-surface floating ball reverser provided by the present invention after the two floating blocks are removed.

[0060] Fig.33 The utility model is a cross-sectional schematic diagram of the assembly relationship between the back plate, the plate spring, the wedge key, the spring pressure plate and the adjustment gasket of the double-reverse-surface floating ball reverser provided by the present invention.

[0061] Fig.34a The back plate structure of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0062] Fig.34b The back plate structure of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0063] Fig.35a The structure of the floating block of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0064] Fig.35b The structure of the floating block of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0065] Fig.36a The structure of the floating block 2 of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 1 .

[0066] Fig.36bThe structure of the floating block 2 of the double reverse surface floating ball reverser provided by the present invention is shown in FIG. Figure 2 .

[0067] Fig.37 It is a schematic diagram of the plate spring structure of the double reverse surface floating ball reverser provided by the present invention.

[0068] Fig.38 It is a schematic diagram of the wedge key structure of the double reverse surface floating ball reverser provided by the present invention.

[0069] Fig.39 It is a structural schematic diagram of a ball separator of a ball screw pair provided by the present invention;

[0070] Fig.40 It is a schematic diagram of the positional relationship between any two adjacent balls and the separator when the ball screw pair provided by the present invention has a ball separator.

[0071] In the drawings of the present invention, the bolts, screws and locating pins involved are not shown, but this does not mean that there are no bolts, screws and locating pins in the relevant assembly.

[0072] Description of reference numerals:

[0073] In the figure, 1. screw shaft; 1c. center line of the screw shaft; 11. helical teeth on the screw shaft; 11a, 11b. grooves on the side of the helical teeth of the screw shaft; 2. screw nut; 21. helical teeth on the screw nut; 21a, 21b. grooves on the side of the helical teeth of the screw nut; 21c, 21d. transitional curved surfaces at both ends of the helical teeth of the screw nut; 22, 23. threaded holes on the screw nut for installing a single-reverse ball reverser; 24, 25. wedge-shaped positioning surfaces on the screw nut for installing a single-reverse ball reverser; 26. windows on the screw nut for installing a double-reverse ball reverser; 27, 28. positioning holes on the screw nut for installing a double-reverse ball reverser 5; 29, 30. positioning holes on the screw nut for installing a double-reverse ball reverser Threaded hole of the deflector 5; 3. Ball; 4. Single-reverse ball deflector; 41. Ball reverse guide groove on the single-reverse ball deflector; 42, 43. Screw holes on the single-reverse ball deflector; 4a, 4b. Upper and lower end faces of the single-reverse ball deflector located in the spiral tooth groove of the screw shaft; 4c. Wedge-shaped positioning surface on the single-reverse ball deflector; 4d. Inner side of the ball deflector 4; 5. Double-reverse ball deflector; 51, 52. Reverse guide groove on the double-reverse ball deflector; 53, 54. Positioning holes on the double-reverse ball deflector; 55, 56. Threaded holes on the double-reverse ball deflector; 5a, 5b. Upper and lower end faces of the double-reverse ball deflector located in the spiral tooth groove of the screw shaft Lower end surface; 61. Back plate of the one-way floating ball reverser; 611. Guide groove on the inner side of the back plate of the one-way floating ball reverser; 612. Keyway on the back plate of the one-way floating ball reverser; 62. Floating block of the one-way floating ball reverser; 621. Reverse guide channel on the floating block of the one-way floating ball reverser; 62a, 62b. Upper and lower end surfaces of the floating block of the one-way floating ball reverser; 62c, 62d. Guide surface of the floating block of the one-way floating ball reverser; 63. Adjustment block of the one-way floating ball reverser; 63a, 63b. Upper and lower end surfaces of the adjustment block of the one-way floating ball reverser; 63c, 63d. 63e. The guide surface on the adjusting block of the single-reverse floating ball reversal device; 631. The spring positioning groove on the adjusting block of the single-reverse floating ball reversal device; 64. The fixing block of the single-reverse floating ball reversal device; 65. The leaf spring of the single-reverse floating ball reversal device; 651. The main elastic action part of the leaf spring 65; 652. The fixed end of the leaf spring 65; 66. The wedge key of the single-reverse floating ball reversal device; 67. The cover plate of the single-reverse floating ball reversal device; 71. The back plate of the double-reverse floating ball reversal device; 711. The guide groove on the inner side of the back plate of the double-reverse floating ball reversal device; 712. The through hole in the middle of the back plate of the double-reverse floating ball reversal device; 72, 73.Two floating blocks of the double reverse surface floating ball reverser; 721, 731. Ball reverse guide grooves on the floating blocks 72 and 73; 722, 732. Spring deformation guide grooves on the floating blocks 72 and 73; 72a, 72b. Upper and lower end surfaces of the floating block 72; 72c, 72d. Floating guide surface on the floating block 72; 73a, 73b. Upper and lower end surfaces of the floating block 73; 73c, 73d. Floating guide surface on the floating block 73; 74, 75. Plate springs of the double reverse surface floating ball reverser; 741. Elastic action portion of the plate spring 74; 742. The fixed end of the plate spring 74; 76. The wedge key of the double reverse floating ball reverser; 761. The wedge-shaped part of the wedge key 76; 762. The fixed end of the wedge key 76; 77. The plate spring pressure plate; 78. The adjustment gasket; 8. The ball separator; 8a, 8b. The concave curved surfaces on both sides of the ball separator that contact the balls; A, B. The direction of the axial load on the ball screw pair; r1. The main arc that constitutes the normal section profile of the single arc groove; r2, r3. The main arc that constitutes the normal section profile of the double arc groove; Δ. The maximum axial clearance between the ball and the screw shaft or the helical teeth of the screw nut. . Specific implementation method:

[0074] The specific embodiments of the present invention will be described in detail below based on the accompanying drawings.

[0075] Figure 1 When the ball screw pair has only one complete ball circulation channel, the ball screw pair comprises a screw shaft 1, a screw nut 2, a plurality of balls 3 and two ball deflectors 4, wherein the two ball deflectors 4 are respectively located at the two ends of the helical teeth of the screw nut.

[0076] Figure 2 The outer cylindrical surface of the screw shaft 1 has a spiral tooth 11, and both sides of the spiral tooth 11 have spiral grooves, denoted as 11a and 11b, which are both spiral motion raceway surfaces of the ball 3. The material of the screw shaft can be selected from metal materials such as GCr15, and the processing of the spiral tooth 11 can be achieved by turning or milling.

[0077] Figure 3 The inner cylindrical surface of the lead screw nut has a spiral tooth 21, and both sides of the spiral tooth have spiral grooves, which are respectively denoted as 21a and 21b. The two grooves are both spiral motion raceway surfaces of the ball. The material of the lead screw nut can be selected from metal materials such as GCr15, and the processing of the spiral tooth 21 can be achieved by turning or milling.

[0078] Figure 4The helical teeth 11 of the screw shaft and the helical teeth 21 of the screw nut are arranged in a cross manner in the axial direction and have the same lead size, thereby forming two spiral channels on both sides of the helical teeth, and multiple balls move in these two spiral channels and transmit axial loads.

[0079] Figure 5 and Figure 6 The two single-reverse surface ball reversers 4 form a ball reverse channel at both ends of the screw nut helical teeth, respectively, so that the balls move from one side of the screw nut helical teeth to the other side of the screw nut helical teeth, thereby forming a complete ball circulation channel.

[0080] Figure 7 When the ball screw pair has only one complete ball circulation channel, multiple balls form a circulating motion chain in the circulation channel.

[0081] Figure 8 and Fig. 9 The two ends of the screw nut helical tooth 21 are provided with transitional curved surfaces 21c and 21d, and have wedge-shaped positioning surfaces and threaded holes for mounting the ball reverser 4. The screw nut helical tooth can be machined by turning, and the wedge-shaped positioning surfaces 24 and 25 can be machined by milling.

[0082] Fig.10 and Fig.11 , a ball reverse guide groove 41 is provided on the side of the ball deflector 4 facing the end face of the helical tooth of the screw nut, and the surface of the groove is the reverse guide action surface of the ball; the upper end face, lower end face 4a and 4b of the ball deflector 4 located in the helical tooth groove of the screw shaft are all helical surfaces, and their lead is the same as the lead of the helical tooth of the screw shaft 1; a wedge-shaped positioning surface 4e is provided on one side of the ball deflector 4, and the wedge-shaped positioning surface 4e cooperates with the wedge-shaped surface 24 or 25 on the screw nut to realize the positioning of the ball deflector 4 on the screw nut; the ball deflector 4 has screw holes 41 and 42, and the screw holes 41 and 42 respectively cooperate with the threaded holes 22 and 23 on the screw nut to realize the fastening of the ball deflector 4 on the screw nut by screws. The ball deflector 4 can be made of metal materials such as CrWMn or engineering plastics such as high-strength nylon, and its processing can be realized by casting and powder metallurgy.

[0083] Fig.12 The reverse guide part on the ball deflector 4 is located in the spiral tooth groove of the screw shaft. At the same time, in order to avoid direct contact between the ball deflector 4 and the screw shaft, there are geometric gaps between the two spiral end faces 4a and 4b of the ball deflector 4 and the spiral teeth of the screw shaft. Similarly, there is a geometric gap between the inner side surface 4d of the ball deflector 4 and the screw shaft.

[0084] Fig.13In the spiral channel of the ball, there is an axial gap Δ between the ball and the spiral raceway surface of the screw shaft or the spiral raceway surface of the screw nut. The axial gap enables the ball to move smoothly in the no-load return channel, thereby allowing the ball to smoothly return to the starting end of the load travel channel.

[0085] Fig.14 and Fig.15 The normal cross-sectional profile of the grooves on the helical tooth side surfaces of the screw shaft 1 and the screw nut 2 are divided into two types: one is a single arc shape and the other is a double arc shape. The normal cross-sectional profile of the single arc groove is mainly composed of a segment of arc r1; the normal cross-sectional profile of the double arc groove is mainly composed of two segments of arc r2 and r3.

[0086] Fig.16 When the ball screw pair has two ball circulation channels, the screw nut helical teeth 21 are divided into two sections along the spiral direction, and there is a window 26 for installing the double reverse surface ball reverser 5 between the two sections of the helical teeth.

[0087] Fig.17 On the outside of the screw nut, there are positioning pin holes 27, 28 and threaded holes 29, 210 for installing the double reverse surface ball reverser.

[0088] Fig.18 and Fig.19 , there is a groove 51 and 52 on each side of the double reverse surface ball deflector 5, and the surfaces of these two grooves are the reverse guiding surfaces of the balls. Similar to the single reverse surface ball deflector 4, the upper end face, lower end face 5a and 5b of the double reverse surface ball deflector 5 located in the spiral tooth groove of the screw shaft are all spiral surfaces, and the lead is the same as the lead of the spiral teeth of the screw shaft. In order to avoid sliding friction between the double reverse surface ball deflector 5 and the screw shaft, there are geometric gaps between the spiral end faces 5a and 5b and the spiral teeth of the screw shaft. In addition, there are positioning pin holes 53, 54 and screw holes 55, 56 on the double reverse surface ball deflector 5, and the positioning pin holes 53, 54 and screw holes 55, 56 are respectively matched with the positioning pin holes 27, 28 and threaded holes 29, 210 on the outside of the screw nut, and are used to fix the ball deflector on the screw nut by positioning pins and screws. The double-reverse-face ball deflector 5 can be manufactured using metals such as CrWMn or engineering plastics such as high-strength nylon, and can be manufactured through processing methods such as casting or powder metallurgy.

[0089] Fig. 20 and Fig.21Through the window 26 on the screw nut, the reverse guiding part of the double reverse surface ball reverser 5 extends from the outside of the screw nut to the inside of the screw nut, and faces the helical tooth end faces of the screw nut on both sides respectively, thereby forming a complete ball circulation channel on both sides of the double reverse surface ball reverser 5, and forming two ball circulation motion chains in these two circulation channels.

[0090] Fig. 22 and 23 The figure shows the inner structure of the single-reverse floating ball deflector implemented in the present invention. The back plate 61 and the fixed block 64 are both fixed on the lead screw nut, and the floating block 62 and the adjustment block 63 can move along the guide groove inside the back plate 61. Because there is a plate spring 65 between the adjustment block 63 and the floating block 62, and the position of the adjustment block 63 relative to the fixed block 64 is usually unchanged, the floating block can float along the guide groove inside the back plate when impacted by the ball.

[0091] Fig.24 The structure of the back plate 61 of the single-reverse floating ball deflector implemented in the present invention is shown. A dovetail spiral guide groove 611 is provided on the inner side of the back plate 61, and its lead is the same as the lead of the spiral tooth of the screw shaft. Because the guide groove 611 can withstand the overturning moment, the floating block 62 and the adjustment block 63 will not be separated from the guide groove when moving along the guide groove. A key groove 612 is provided on the side of the back plate 61 close to the fixed block 64, and the wedge key 66 penetrates from the outer side of the back plate 71 to the inner side through the key groove. The back plate 61 can be made of high-strength engineering plastics and metals, and the blank is manufactured by casting or powder metallurgy, and then finely processed by forming milling or grinding.

[0092] Fig.25a and 25b The structure of the floating block 62 of the single-reverse floating ball deflector implemented in the present invention is shown. A groove 621 for guiding the ball to reverse is provided on one side of the floating block 62; the upper end face, the lower end face 62a and 62b of the floating block 62 are all helical surfaces with the same lead as the helical teeth of the screw shaft; the outer side of the floating block 62 has dovetail guide surfaces 62c and 62d for matching with the guide groove 611 on the inner side of the back plate 61. The floating block 62 can be made of high-strength engineering plastics and metals, and the blank is manufactured by casting or powder metallurgy, and then finished by milling and grinding.

[0093] Fig.26a , Figure 26b and Fig.26cThe structure of the adjustment block 63 of the single-reverse floating ball deflector implemented in the present invention is shown, wherein the side close to the fixed block 64 has a wedge surface 63e for cooperating with the wedge key 66, and the side close to the floating block 62 has a groove 631 for limiting the displacement of the fixed end of the leaf spring 65. The adjustment block 63 can be made of materials such as engineering plastics and metals, and the part blank is manufactured by casting or powder metallurgy, and then finished by milling.

[0094] Fig. 27 The structure of the leaf spring 65 of the single-reverse floating ball reverser implemented in the present invention is shown, wherein one end 652 with a folded edge is a fixed end, the other end is a free end, and the bent portion 651 in the middle is the main elastic deformation portion of the leaf spring.

[0095] Fig.28 The assembly position relationship among the back plate, wedge key and adjustment block of the single-reverse floating ball reverser implemented in the present invention is shown.

[0096] Fig.29 The assembly position relationship among the back plate, wedge key, adjustment block and fixed block of the single-reverse floating ball reverser implemented in the present invention is shown.

[0097] Fig.30 The figure shows the assembly position relationship between the back plate, the fixing block and the cover plate of the single-reverse floating ball deflector implemented in the present invention.

[0098] Fig.31a and 31b The structure of the double reverse surface floating ball reverser implemented in the present invention is shown, and both the floating blocks 72 and 73 can float along the guide groove 711 on the inner side of the back plate 71.

[0099] Fig.32 and Fig.33 The structure of the double reverse surface floating ball deflector implemented in the present invention after the floating blocks 72 and 73 are removed is shown. The elastic action parts of the two leaf springs 74 and 75 are both located between the two floating blocks 72 and 73, and the wedge-shaped part of the wedge-shaped key 76 is located between the elastic action parts of the two leaf springs, and the deformation of the leaf springs is adjusted by the wedge-shaped key 76. A spring pressure plate 77 and an adjustment gasket 78 are provided between the fixed ends of the leaf springs 74 and 75 and the fixed ends of the wedge-shaped block 76, and the position of the wedge-shaped key 76 is adjusted by changing the thickness of the adjustment gasket 78.

[0100] Fig.34a34b shows the structure of the back plate 71 of the double reverse surface floating ball deflector implemented in the present invention, with a guide groove 711 on the inner side of the back plate, and a through hole 712 in the middle of the back plate, which is used to allow the leaf springs 74, 75 and the wedge key 76 to extend from the outer side of the back plate to the inner side of the back plate. The back plate 71 can be made of materials such as engineering plastics and metals, and the blank can be manufactured by casting or powder metallurgy, and then the through hole 712 and the guide groove 711 and other structures can be processed by milling, grinding and other methods.

[0101] Fig.35a , Fig.35b , Fig.36a and Fig.36b The structure of two floating blocks 72 and 73 of the double reverse-surface floating ball deflector implemented in the present invention is shown. There is a groove on both floating blocks to guide the ball reverse, and the two grooves face the spiral tooth end faces of the screw nut on both sides of the deflector respectively; the upper end face and the lower end face of the two floating blocks are spiral surfaces, and the lead is the same as the lead of the spiral teeth of the screw shaft; there are spring deformation guide grooves 722 and 732 on the side of the two floating blocks close to the leaf spring, which are used to constrain the displacement of the free end of the leaf spring. The floating blocks 72 and 73 can be manufactured using high-strength engineering plastics and metals, and the blanks can be manufactured by casting or powder metallurgy, and then finished by milling or grinding.

[0102] Fig.37 The structure of the plate spring 74 of the double reverse floating ball reverser of the present invention is shown, and there are two through holes at its fixed end 742 for screw fastening. The structure of the plate spring 75 is the same as that of 74.

[0103] Fig.38 The structure of the wedge-shaped key 76 of the double-reverse-surface floating ball reverser implemented in the present invention is shown, and there are four countersunk holes at its fixed end 762, which are also used for screw fastening.

[0104] Fig.39 The figure shows the positional relationship between two adjacent balls and the intermediate separator when the ball screw pair of the present invention has a ball separator. In a ball circulating chain, the number of separators is determined according to the use requirements.

[0105] Fig.40 The structure of the ball separator 8 implemented in the present invention is shown, and its two side surfaces 8a and 8b in contact with the balls are both concave spherical surfaces, and the radii of the two concave spherical surfaces are both larger than the radius of the balls.

[0106] A ball screw pair includes a screw shaft 1, a screw nut 2, balls 3 and a ball reverser 4. The screw shaft 1 has helical teeth 11 on its outer cylindrical surface, and the screw nut 2 has helical teeth 21 on its inner cylindrical surface. The helical teeth 11 of the screw shaft and the helical teeth 21 of the screw nut are arranged in a cross manner in the axial direction, that is, the helical teeth 11 of the screw shaft are located between the tooth grooves of the helical teeth 21 of the screw nut, and the helical teeth 21 of the screw nut are also located between the tooth grooves of the helical teeth 11 of the screw shaft, thereby forming two spiral channels on both sides of the spiral teeth, namely, the spiral channel 1 and the spiral channel 2 of the balls. There are spiral grooves (11a, 11b, 21a, 21b) on the side surfaces of the helical teeth of the screw shaft and the helical teeth of the screw nut, and the surfaces of these grooves are the spiral motion raceway surfaces of the balls. There is a single-reverse ball reverser 4 at both ends of the screw nut helical teeth 21. The ball reverser 4 forms a ball reverse channel at both ends of the screw nut helical teeth, namely, ball reverse channel 1 and ball reverse channel 2. Through these two reverse channels, the balls can be guided from either side of the screw nut helical teeth to the other side, thereby forming a complete roller circulation channel around the screw nut helical teeth. In a complete ball circulation channel, multiple balls are arranged to form a ball circulation chain.

[0107] The spiral channel 1 and the spiral channel 2 are both the load travel channel of the ball and the unloaded return channel of the ball, that is, when the ball screw pair is subjected to an axial load in any direction (direction A or direction B), one of the ball spiral channel 1 and the ball spiral channel 2 that transmits the axial load is the load travel channel of the ball, and the other is also the unloaded return channel of the ball. When the axial load is reversed, the original load travel channel becomes the unloaded return channel, and the original unloaded return channel becomes the load travel channel. The maximum axial clearance between the ball and the spiral raceway surface of the screw shaft or the spiral raceway surface of the screw nut allows the ball to move smoothly in its unloaded return channel.

[0108] In the spiral channel 1 and the spiral channel 2, the contact angles α of the balls when transmitting axial loads are in opposite directions, so the balls in the two channels can be used to transmit axial loads in opposite directions respectively.

[0109] The normal cross-sectional profiles of the grooves on the helical tooth side surfaces of the screw shaft 1 and the screw nut 2 are both single arc and double arc. The normal cross-sectional profile of the single arc groove is mainly composed of a segment of arc (r1), and the normal cross-sectional profile of the double arc groove is mainly composed of two segments of arc (r2 and r3). ​​When the screw shaft 1 and the screw nut 2 are matched, the normal cross-sectional profiles of the grooves on the helical tooth side surfaces are the same.

[0110] The two ends of the screw nut helical tooth 21 have transitional curved surfaces 21c and 21d.

[0111] The ball screw pair is allowed to have two or more complete ball circulation channels. When the ball screw pair has two or more complete ball circulation channels, the screw nut helical teeth 21 are divided into two or more discontinuous sections in the spiral direction, and both ends of each section of the screw nut helical teeth have transitional curved surfaces; there is a gap between any two adjacent end faces of the screw nut helical teeth, and a double reverse surface ball deflector 5 is set in the gap; because the ball spiral channel 1 and the spiral channel 2 are divided into two or more sections by the double reverse surface ball deflector 5, each section of the screw nut helical teeth and the ball deflectors (4 or 5) at both ends form a complete ball circulation channel, and a ball circulation chain can be provided in each circulation channel.

[0112] The reverse guide groove 41 on the single reverse face ball reverser 4 and the reverse guide grooves 51 and 52 on the double reverse face ball reverser 5 are both located between the tooth grooves of the helical teeth of the screw shaft and face the end faces of the helical teeth of the screw nut. The upper end faces and lower end faces of the reverse guide parts of the ball reversers 4 and 5 are both helical surfaces with the same lead as the helical teeth of the screw shaft, and there are geometric gaps between the adjacent helical teeth of the screw shaft.

[0113] The ball screw pair allows the use of a floating ball reverser. When the ball screw pair uses a floating ball reverser, the single-reverse surface ball reverser 4 and the double-reverse surface ball reverser 5 are replaced by a single-reverse surface floating ball reverser and a double-reverse surface floating ball reverser, respectively.

[0114] The single-reverse floating ball reverser is mainly composed of a back plate 61, a floating block 62, an adjusting block 63, a fixed block 64, a plate spring 65, a wedge key 66 and a cover plate 67; the back plate 61 and the fixed block 64 are fixed to the lead screw nut by screws, and a guide groove 611 is provided on the inner side of the back plate 611, and the guide track of the guide groove 611 is a spiral line, and the lead is the same as the lead of the spiral tooth of the lead screw shaft; the floating block 62 and the adjusting block 63 are provided with a guide surface 611. 2c, 62d, 63c and 63d, these guide surfaces are matched with the guide groove 611 on the inner side of the back plate 61, so that the floating block and the adjusting block can move along the guide groove 611 of the back plate; the wedge key 66 is located between the fixed block 64 and the adjusting block 63, and the wedge surface of the wedge key 66 is matched with the wedge surface 63e of the adjusting block 63; the plate spring 65 is located between the adjusting block 63 and the floating block 62, and the fixed end 652 of the plate spring 65 is embedded in the groove 63 of the adjusting block 63. 1, when the plate spring 65 undergoes elastic deformation, the position of its fixed end 652 is relatively fixed, while the other end can move freely on the adjustment block; by adjusting the position of the wedge key 66, the adjustment block 63 can be moved along the back plate guide groove 611, so that the distance between the adjustment block 63 and the floating block 62 and the compression deformation of the plate spring 65 can be changed; the floating block 62 has a channel 621 for guiding the ball to move in the reverse direction, and when the ball just enters the reverse channel, the floating block 62 can float along the back plate guide groove 611 under the impact of the ball; the upper end surface and the lower end surface (62a, 62b, 63a and 63b) of the floating block 62 and the adjustment block 63 are all helical surfaces, and the lead is the same as the lead of the helical teeth of the screw shaft; the cover plate 67 is located outside the large end of the wedge key 66, and an adjustment gasket is provided between the cover plate 67 and the fixed block 64 and the back plate 61, and the position of the wedge key 66 can be adjusted by changing the thickness of the adjustment gasket.

[0115] The double reverse surface floating ball reverser is mainly composed of a back plate 71, a floating block 72, a floating block 73, plate springs 74 and 75, a wedge key 76, a spring pressure plate 77 and an adjusting gasket 78; a guide groove 711 is provided on the inner side of the back plate 71, and the guide track of the guide groove 711 is a spiral line, and the lead is the same as the lead of the screw shaft helical tooth 11; floating guide surfaces 72c, 72d, 73c and 73d are provided on the floating blocks 72 and 73, and the floating guide surfaces 72c, 72d, 73c, 73d are all matched with the guide groove 711 of the back plate, so that the floating block can move along the guide groove 711 of the back plate; there is a ball reverse guide groove on each of the floating blocks 72 and 73, and the two grooves face the end faces of the helical teeth of the screw nut on both sides of the reverser 7 respectively; the two plate springs 7 4 and 75 have the same structure, and they and the wedge key 76 are both located between the two floating blocks 72 and 73, and the deformation of the leaf springs 74 and 75 can be adjusted by the wedge key 76; a through hole 712 is provided in the middle of the back plate 71, and the wedge-shaped part of the wedge key 76 and the elastic action part of the leaf springs 74 and 75 are both penetrated from the outside of the back plate to the inside of the back plate through the hole 712; the spring pressure plate 77 and the adjusting gasket 78 are both located between the fixed ends of the leaf springs 74, 75 and the wedge key 76, and the position of the wedge key 76 relative to the leaf springs 74 and 75 can be adjusted by changing the thickness of the adjusting gasket 78, thereby adjusting the deformation of the leaf spring and the size of the preload; the wedge key 76, the leaf springs 74 and 75, the spring pressure plate 77 and the adjusting gasket 78 are all fixed to the back plate 71 by screws.

[0116] The fixing method of the single-reverse surface floating ball reverser on the screw nut 2 is the same as the fixing method of the non-floating single-reverse surface ball reverser 4 on the screw nut 2; the fixing method of the double-reverse surface floating ball reverser on the screw nut 2 is the same as the fixing method of the non-floating double-reverse surface ball reverser 5 on the screw nut 2.

[0117] In the ball circulation channel of the ball screw pair, a ball separator 8 is allowed to be arranged between adjacent balls. When there is a separator 8 between the balls, direct contact or collision between adjacent balls can be avoided, which is conducive to reducing vibration and noise; the two side surfaces 8a and 8b on the ball separator 8 that contact the balls are both concave spherical surfaces, and the radius of the two concave spherical surfaces is greater than the ball radius.

[0118] The ball screw pair implemented by the present invention is not limited to a structure with only one or two ball circulation channels, but also includes a structure with multiple ball circulation channels. When the ball screw pair has n (n>2) ball circulation channels, the screw nut helical teeth 21 are divided into n discontinuous sections along the spiral direction, and there is a double reverse surface ball deflector between any two adjacent sections of the screw nut helical teeth, and there is also a ball deflector at the starting end of the first screw nut helical tooth and the terminal end of the last screw helical tooth. At this time, the total number of ball deflectors is n+1. In order to make the structure of the ball screw pair compact, the ball deflectors are evenly distributed in the circumferential direction of the screw nut. For example, when the ball screw pair has two, three or four ball circulation channels, the equally spaced angles of the ball deflectors in the circumferential direction of the screw nut are 180°, 120° and 90° respectively.

[0119] The screw shaft 1 of the ball screw pair implemented in the present invention is not limited to a solid shaft, but also includes a hollow shaft.

[0120] The balls of the ball screw pair implemented in the present invention are not limited to metal balls, but also include non-metal balls such as ceramics.

[0121] Damping elements can be arranged between the floating block 62 and the adjusting block 63 of the single-reverse-surface floating ball reverser and between the two floating blocks 72 and 73 of the double-reverse-surface floating ball reverser to further reduce the vibration and noise caused by the ball impacting the reverser.

[0122] When the ball screw pair of the present invention is subjected to axial loads in opposite directions, the screw shaft or screw nut may experience axial movement due to the existence of its internal axial clearance. To this end, a double screw nut adjustment and pre-tightening method can be used to avoid this. The so-called double screw nut adjustment and pre-tightening method is to assemble two screw nuts on the same screw shaft, and by adjusting the axial position between the two screw nuts, the balls in the two screw nuts are subjected to pre-tightening forces in opposite directions. Because the contact angles of the balls subjected to the pre-tightening forces in the two screw nuts are in opposite directions, the balls in the two screw nuts can respectively withstand axial loads in opposite directions, thereby avoiding the axial movement that occurs when there is only one screw nut. In the prior art, the double screw nut adjustment and pre-tightening method of the ball screw pair includes a double nut tooth difference adjustment and pre-tightening method, a double nut thread adjustment and pre-tightening method, a double nut gasket adjustment and pre-tightening method, etc. The ball screw pair implemented by the present invention can also be adjusted and pre-tightened by these methods.

[0123] The ball screw pair provided by the present invention is not limited to the above-mentioned embodiments, but also includes other embodiments that can realize its structure and function.

[0124] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements of the present invention by relevant technical personnel in the field should be expanded within the scope of protection determined by the claims of the present invention.

Claims

1. A ball screw pair, comprising a screw shaft, a screw nut, a ball and a ball reverser, wherein the outer cylindrical surface of the screw shaft and the inner cylindrical surface of the screw nut are both provided with helical teeth, and the helical teeth of the screw shaft and the helical teeth of the screw nut are arranged in a cross manner in the axial direction, that is, the helical teeth of the screw shaft are located between the tooth grooves of the helical teeth of the screw nut, and the helical teeth of the screw nut are located between the tooth grooves of the helical teeth of the screw shaft; spiral grooves are provided on both side surfaces of the helical teeth of the screw shaft and the two side surfaces of the helical teeth of the screw nut, and the spiral direction and lead of the spiral grooves are the same as those of the spiral teeth; the spiral grooves on the side surfaces of the spiral teeth are used as the spiral motion raceway surface of the ball, and the two spiral grooves on the side surfaces of the spiral teeth of the screw shaft are provided with a spiral groove. The groove and the two spiral grooves on the side of the spiral teeth of the screw nut form two spiral ball movement channels, which are respectively recorded as ball spiral channel 1 and ball spiral channel 2; there is a ball reverser at each end of the spiral teeth of the screw nut, and the ball reverser forms a ball reverse channel at each end of the spiral teeth of the screw nut, which are recorded as ball reverse channel 1 and ball reverse channel 2. The balls can move from any side of the nut spiral teeth to the other side through these two reverse channels; the ball spiral channel 1, the ball spiral channel 2, the ball reverse channel 1 and the ball reverse channel 2 together form a complete ball circulation channel, and multiple balls form a motion circulation chain in a complete ball circulation channel; The normal cross-sectional profile of the spiral groove on the side surface of the spiral tooth of the screw shaft is in the shape of a single arc or a double arc, the normal cross-sectional profile of the single arc groove is mainly composed of one arc, and the normal cross-sectional profile of the double arc groove is mainly composed of two arcs; similarly, the normal cross-sectional profile of the spiral groove on the side surface of the spiral tooth of the screw nut is also in the shape of a single arc or a double arc; the groove on the side surface of the spiral tooth of the screw nut has a transitional curved surface at both ends of the spiral tooth of the screw nut; The reverse guiding action surfaces on the ball deflector are all located between the tooth grooves of the helical teeth of the screw shaft and face the end faces of the helical teeth of the screw nut; when only one side of the ball deflector has a ball reverse guiding action surface, it is recorded as a single reverse surface ball deflector; when both sides of the ball deflector have ball reverse guiding action surfaces, it is recorded as a double reverse surface ball deflector, and the two reverse guiding action surfaces on the double reverse surface ball deflector face the end faces of the helical teeth of the screw nut on both sides of the deflector respectively; the upper end face and the lower end face of the ball deflector located in the helical tooth grooves of the screw shaft are both spiral surfaces, and their leads are the same as the leads of the helical teeth of the screw shaft, and there are geometric gaps between these two end faces and the adjacent side faces of the helical teeth of the screw shaft; The ball screw pair adopts a floating ball deflector, and the ball reverse guiding surface on the floating ball deflector can float along the spiral tooth groove of the screw shaft under the impact load of the ball, and has stiffness and damping that meet the use requirements in the floating direction; when the floating ball deflector has only one ball reverse guiding surface, it is recorded as a single reverse surface floating ball deflector; when it has two reverse guiding surfaces, it is recorded as a double reverse surface floating ball deflector; when the ball screw pair adopts a floating ball deflector, the single reverse surface ball deflector or the double reverse surface ball deflector is replaced by a single reverse surface floating ball deflector or a double reverse surface floating ball deflector respectively; The single-reverse surface floating ball reverser includes a back plate, a floating block, an adjustment block, a fixed block, an elastic element, a wedge key and a cover plate; the back plate is fixed on the lead screw nut, and a guide groove is provided on the inner side of the back plate, and the guide track of the guide groove is a spiral line, and the lead of the spiral line is the same as the lead of the spiral tooth groove of the lead screw shaft; the floating block and the adjustment block are both provided with guide surfaces, and the guide surfaces can make the floating block and the adjustment block move along the guide groove on the back plate; the fixed block is fixed on the lead screw nut, the wedge key is located between the fixed block and the adjustment block, and the elastic element is located between the adjustment block and the floating block, and the position of the wedge key is adjusted to make the adjustment block move along the guide groove The floating block moves along the guide groove on the back plate, thereby changing the distance between the adjustment block and the floating block and the deformation of the elastic element; the floating block has a ball reverse guiding action surface, and the elastic element applies a pre-tightening force to the floating block after being compressed and deformed, so that the floating block can float along the guide groove of the back plate when impacted by the ball; the upper end face and lower end face of the floating block and the upper end face and lower end face of the adjustment block are all spiral surfaces, and the lead of the spiral surface is the same as the lead of the spiral teeth of the screw shaft; the cover plate is located outside the large end of the wedge key, and an adjusting gasket is provided between the cover plate and the fixed block, and the position of the wedge key is adjusted by changing the thickness of the adjusting gasket; The double reverse surface floating ball reverser comprises a back plate, a floating block 1, a floating block 2, a wedge key, an elastic element and an adjusting gasket; the inner side of the back plate is provided with a guide groove, the guide track of the guide groove is a spiral line, and the lead of the spiral line is the same as the lead of the spiral teeth of the screw shaft; the floating block 1 and the floating block 2 are both provided with floating guide surfaces, and the floating guide surfaces can enable the floating blocks to move along the guide grooves on the back plate; the floating block 1 and the floating block 2 are respectively provided with a ball reverse guide channel, and the two ball reverse guide channels respectively face the end faces of the spiral teeth of the screw nut on both sides of the reverser; the upper end face and the lower end face of the floating block 1 and the floating block 2 are both spiral surfaces, and the lead of the spiral surfaces is the same as the lead of the spiral teeth of the screw shaft; the elastic action of the elastic element The wedge-shaped part of the wedge-shaped key and the elastic part of the wedge-shaped key are both located between the floating block one and the floating block two, and the deformation of the elastic element is adjusted by the wedge-shaped key. After the elastic element is deformed by pressure, a preload is applied to the floating block; a through hole is provided in the middle of the back plate, and the elastic action part of the elastic element and the wedge-shaped part of the wedge-shaped key both penetrate into the inner side of the back plate from the through hole in the middle of the back plate; the fixed ends of the elastic element and the wedge-shaped key are both located on the outer side of the back plate, and the adjusting gasket is located between the fixed ends of the elastic element and the wedge-shaped key. By changing the thickness of the adjusting gasket, the relative position between the wedge-shaped key and the elastic element is adjusted, thereby changing the deformation of the elastic element and the size of the preload; the wedge-shaped key, the elastic element and the adjusting gasket are all fixed on the back plate of the double-reverse-surface floating ball reverser.

2. The ball screw pair according to claim 1, characterized in that: The ball screw channel 1 and the ball screw channel 2 are both loaded travel channels for the balls and unloaded return channels for the balls; When the ball screw pair is subjected to an axial load, one of the ball screw channels 1 and 2 for transmitting the axial load is a load-carrying channel for the ball, and the other channel is simultaneously a load-free return channel for the ball; When the axial load is reversed, the original ball load travel channel is transformed into the ball no-load return channel, and at the same time, the original ball no-load return channel is transformed into the ball load travel channel; an axial gap is provided between the ball and the spiral raceway surface of the screw shaft or the spiral raceway surface of the screw nut, and the size of the axial gap can allow the ball to move smoothly in its no-load return channel.

3. The ball screw pair according to claim 1, characterized in that In the ball spiral channel one and the ball spiral channel two, the contact points of the balls with the spiral raceway surfaces of the screw shaft and the spiral raceway surfaces of the screw nut when transmitting axial loads are both located within the normal sections of the spiral channels, and within the normal sections of the two spiral channels, the angles between the lines connecting the centers of the balls and the raceway contact points and the perpendiculars to the axes of rotation of the spiral channels are in opposite directions, that is, the directions of the contact angles α are in opposite directions.

4. The ball screw pair according to claim 1, characterized in that: The ball screw pair has multiple complete ball circulation channels, the screw nut helical teeth are divided into two or more discontinuous sections in the spiral direction, and both ends of each section of the screw nut helical teeth have transitional curved surfaces; there is a gap between the end faces of any two adjacent sections of the screw nut helical teeth, and a double-reverse-face ball reverser is arranged in the gap, and the ball spiral channel 1 and the ball spiral channel 2 are both divided into two or more sections by the double-reverse-face ball reverser; each section of the spiral teeth of the screw nut and the ball reversers at both ends form a complete ball circulation channel, and multiple balls form a motion circulation chain in each circulation channel.

5. The ball screw pair according to any one of claims 1 to 4, characterized in that In the ball circulation channel of the ball screw pair, ball separators are respectively arranged between adjacent balls to separate adjacent balls. The two side surfaces of the ball separators in contact with the balls are both concave spherical surfaces, and the radii of the two concave spherical surfaces are both larger than the ball radius.

6. The ball screw pair according to any one of claims 1 to 4, characterized in that: The screw nut pair adopts double screw nut adjustment and pre-tightening, and the double screw nut adjustment and pre-tightening method of the ball screw pair includes double nut tooth difference adjustment pre-tightening, double nut thread adjustment pre-tightening, and double nut gasket adjustment pre-tightening.

7. The ball screw pair as claimed in claim 5, characterized in that: The screw nut pair adopts double screw nut adjustment and pre-tightening, and the double screw nut adjustment and pre-tightening method of the ball screw pair includes double nut tooth difference adjustment pre-tightening, double nut thread adjustment pre-tightening, and double nut gasket adjustment pre-tightening.

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