TWM455099U - Ball screw device and bearing bush assembly thereof - Google Patents

Abstract

A bearing bush assembly of a ball screw is disclosed. The bearing bush assembly is mounted on the screw and includes two bearing bushes, an annular locating element and a preloading regulating element. Each of the bearing bushes respectively has a inner locating groove and a inner ball groove. The inner ball grooves are disposed corresponding to a plurality of outer ball groove. The annular locating elements are respectively disposed between the baring bushes, and the annular locating element is accommodated in the inner locating groove. The preloading regulating element is disposed between the baring bushes. The present invention also discloses a ball screw device.

Description

Ball screw device and its bearing sleeve assembly

This creation relates to a ball screw device and its bearing sleeve assembly.

Rotary ball screw is a device widely used in many mechanical devices. Its purpose is to provide precise transmission function, which can achieve the rotary motion and linear motion in mechanical operation, so that the loaded machine or object can be in a straight line. Actuate in the direction.

In the rotary ball screw of the prior art, a screw, a nut, a plurality of balls and a two bearing sleeve are mainly included. The surface of the screw has a spiral groove, and the inner surface of the nut also has a spiral inner groove to form a first ball passage with the screw. The two bearing sleeves are sleeved on the outer circumference of the nut, and the outer surface of the nut has two outer ball grooves, and forms a second ball passage with the inner ball grooves of the two bearing sleeves. The first ball channel and the second ball channel are provided with a plurality of balls. The balls can respectively assist the nut and the screw, and the relative rotation of the bearing sleeve and the nut, so that the mechanical components carried by the rotary ball screw can be linearly moved along the axial direction of the screw, and also because the rotary ball screw is simultaneously realized. The movement behavior of rotation and linear movement provides two different setting options: the screw is not fixed, the nut is fixed, or the nut is not fixed, and the screw is fixed.

However, regardless of the setting method, the ball screw is usually used in industries such as semiconductors and mechanical assembly that require high precision and high stability. A defect in the product. Among them, especially the smooth running of the ball in the ball channel is the main influencing factor, but the ball channel is composed of different components, so each component must be accurately matched with each other, in practice, two bearings After the sleeve is combined with the nut, it is necessary to have a stepless ball passage to maintain the smooth running of the ball.

Therefore, the accuracy of the outer surface of the bearing sleeve and its outer ball groove is the key to maintaining the stability of the rotary ball screw during operation. However, at present, the design of the bearing sleeve can only separately grind the outer surface of the two bearing sleeves and the inner ball groove, which will cause errors in the assembly of the two bearing sleeves. For example, when the outer surface of the two bearing sleeves is assembled, there is a situation of unevenness, and the combination with the loaded machine table or object causes an error, or the inner ball groove forms a step difference with the outer ball groove of the nut, thereby causing the ball screw. The operation is unstable and noisy, and even dangerous.

Therefore, how to provide a ball screw device and its components, after the two bearing sleeves are assembled with the nut, the outer surface of the bearing sleeve is not uneven, and a complete stepless ball passage is formed to ensure the application. At the time, the ball screw unit can perform precise and stable operation, and has become one of the important topics.

In view of the above problems, the purpose of the present invention is to provide a ball screw device and a bearing sleeve assembly thereof. After the two bearing sleeves and the nut are assembled, the outer surface of the bearing sleeve as a whole does not have unevenness and the internal formation is complete. There is no stepping ball passage to ensure precise and stable operation of the ball screw unit as a whole.

In order to achieve the above object, the bearing sleeve assembly of the ball screw device is sleeved on a nut, and the bearing sleeve assembly comprises two bearing sleeves, an annular positioning component and a pre-stressing adjustment component. The bearing sleeve has an inner positioning groove and an inner ball groove, and the inner ball groove and the screw A plurality of outer ball grooves of the cap are correspondingly arranged. The annular positioning element is sandwiched between the two bearing sleeves, and the annular positioning element is received in the inner positioning groove. The preload adjusting component is sandwiched between the two bearing sleeves.

In order to achieve the above object, the present invention further provides a ball screw device comprising a screw, a nut, a bearing sleeve, an annular positioning component and a preload adjusting component. The nut is sleeved on the screw, and the first ball passage is arranged between the nut and the screw, and the outer surface of the nut has a plurality of outer ball grooves. The bearing sleeves respectively have an inner positioning groove and an inner ball groove, and the inner ball groove is correspondingly arranged with the ball groove outside the nut. The annular positioning element is sandwiched between the two bearing sleeves, and the annular positioning element is received in the inner positioning groove. The preload adjusting component is sandwiched between the two bearing sleeves. Wherein, the two bearing sleeves, an annular positioning component and a pre-stressing adjustment component together form a bearing sleeve assembly.

In a preferred embodiment of the present invention, one of the outer surfaces of the annular positioning member abuts against one of the side walls of the inner positioning groove.

In a preferred embodiment of the present invention, the annular positioning member is received in the inner positioning recess in a manner concentric with the two bearing sleeves.

In a preferred embodiment of the present invention, the inner diameter of the preloading adjustment member is greater than the outer diameter of the annular positioning member.

In a preferred embodiment of the present invention, the two bearing sleeves and the preload adjusting members are fixed to each other in a screw locking manner.

According to the above description, according to the ball screw device and the bearing sleeve assembly thereof, the design of the positioning groove and the annular positioning component in the bearing sleeve and the annular positioning component are accommodated in the inner positioning groove The relative position of the two bearing sleeves is fixed by the annular positioning element. The design of the bearing sleeve assembly allows the two bearing sleeves to be ground in the manner of the assembly, and Grinding the inner wall surface to form an inner ball groove, so as to avoid the error caused by the prior art two bearing sleeves being placed in different times, using different jigs or fractional grinding, thereby causing high and low variations on the surface or joint after assembly. The situation is not the same. Therefore, the outer surface of the ball screw device formed by the present invention has high precision, and can be closely matched with the machine table or other objects to maintain the stability of the equipment during operation.

In addition, the design of the bearing sleeve assembly can further grind the inner wall surface of the two bearing sleeves to form the inner ball groove, which can also reduce the height error caused by the split grinding of the inner ball grooves of different bearing sleeves, thereby reducing After the bearing sleeve and the nut are assembled, there is a problem of a step difference between the internal components.

[study]

no

[this creation]

1‧‧‧Ball screw device

11‧‧‧ screw

111, 123‧‧‧ spiral groove

12‧‧‧ Nuts

121‧‧‧Outer ball groove

122‧‧‧through hole

13a, 13b‧‧‧ bearing sleeve

131a, 131b‧‧‧ inside ball groove

Positioning groove in 132a, 132b‧‧

133a, 133b‧‧‧ side wall

134a, 134b‧‧‧ outer surface

135a, 135b‧‧‧ inner wall

14‧‧‧Ring positioning elements

141‧‧‧ outer surface

15‧‧‧Preloading adjustment components

16‧‧‧ balls

17‧‧‧Dust-proof parts

18‧‧‧End cover

181‧‧‧Return path

19‧‧‧Ball retainer

A‧‧‧ bearing sleeve assembly

F‧‧‧ fixture

P‧‧‧Drive connector

S1‧‧‧ screw hole

S2‧‧‧ screws

S10~S40‧‧‧Steps

1 is a schematic view of a ball screw device according to an embodiment of the present invention.

2 is an exploded perspective view of the ball screw device shown in FIG. 1.

3 is a schematic cross-sectional view of the ball screw device shown in FIG. 1.

4A is a partial cross-sectional view of the bearing sleeve assembly of FIG. 3.

4B is an exploded perspective view of the bearing sleeve and the preload adjusting member shown in FIG. 4A.

FIG. 5 is a flow chart showing the steps of a method for grinding a bearing sleeve assembly according to an embodiment of the present invention.

6 is a flow chart showing the steps of a method of grinding a bearing sleeve assembly according to another embodiment of the present invention.

FIG. 7 is a schematic view showing the installation manner of step S34 shown in FIG. 6.

Hereinafter, a ball screw device and a bearing sleeve assembly thereof according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

1 is a schematic view of a ball screw device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the ball screw device shown in FIG. 1. Referring to FIG. 1 and FIG. 2 simultaneously, the ball screw device 1 includes a screw 11, a nut 12, two bearing sleeves 13a, 13b, an annular positioning member 14, and a preload adjusting member 15. The screw 11 is a cylindrical rod body, and its outer surface has a spiral groove 111 continuously wound along the longitudinal axis. The nut 12 is an annular cylinder having a plurality of outer ball grooves 121, and a through hole 122 is formed in the center of the nut 12, and the inner surface of the nut 12 near the through hole 122 has a spiral groove 123 and a spiral The pitch and groove surface configuration of the groove 123 is the same as or similar to the spiral groove 111 of the screw 11. When the nut 12 is sleeved on the screw 11 through the through hole 122, the spiral groove 123 of the nut 12 and the spiral groove 111 of the screw 11 can correspond to each other to form a first ball passage.

3 is a schematic cross-sectional view of the ball screw device shown in FIG. 1, please refer to FIG. 2 and FIG. 3 at the same time. The first ball passage is a main part of the ball circulation passage between the screw 11 and the nut 12, and accommodates a plurality of balls 16 (only some of the balls are shown in FIGS. 2 and 3), so that the nut 12 can be the screw 11 The axis rotates on the longitudinal axis to convert the rotational motion into a linear motion. It should be noted that the ball reflow method of the present invention is not limited to the outer circulation type, the inner circulation type or the end cover circulation type. In this embodiment, only the end cover circulation type is taken as an example, but this is not For the detailed description, please refer to the following. The arrangement of the screw and the nut and the formation of the groove are understood by those of ordinary skill in the art to which the present invention belongs, and therefore will not be described again.

In addition, as shown in FIG. 3, the bearing sleeves 13a, 13b are respectively sleeved on the nut 12 On both sides, the nut 12 has a plurality of outer ball grooves 121. In the embodiment, the nut 12 has two outer ball grooves 121, and the bearing sleeves 13a, 13b respectively have an inner ball groove 131a, 131b. And the configuration of the surrounding mode, the guiding distance and the groove corresponds to the outer ball groove 121, so that when the bearing sleeves 13a, 13b are sleeved on the nut 12, the inner ball grooves 131a, 131b can be grooved with the outer ball groove. 121 forms a second ball passage for receiving a plurality of balls 16 for enabling rotation of the nut 12 relative to the bearing sleeves 13a, 13b. The outer ball groove 121 is formed perpendicular to the axial direction of the screw 11. Of course, in other embodiments, the outer ball groove 121 may be inclined with respect to the axial direction of the screw 11 to have an angle. This creation is not limited here.

4A is a partial cross-sectional view of the bearing sleeve assembly shown in FIG. 3, and FIG. 4B is an exploded perspective view of the bearing sleeve and the preload adjusting member shown in FIG. 4A. Please refer to FIG. 3 to FIG. 4B at the same time. The two bearing sleeves 13a, 13b each have an inner positioning groove 132a, 132b, and the ball screw device 1 further has an annular positioning member 14. The annular positioning element 14 is interposed between the two bearing sleeves 13a, 13b, and the annular positioning elements 13a, 13b are received in the inner positioning grooves 132a, 132b. Preferably, the outer surface 141 of the annular positioning member 14 abuts against the side walls 133a, 133b of the inner positioning grooves 132a, 132b, and the annular positioning member 14 is received in the inner positioning concave manner concentrically with the two bearing sleeves 13a, 13b. In the grooves 132a, 132b, thereby the bearing sleeve 13a and the bearing sleeve 13b are positioned relative to one another, because of the annular positioning element 14, the tolerance of the alignment between the bearing sleeves 13a, 13b can be significantly reduced. Since the relative position between the annular positioning element 14 and the bearing sleeves 13a, 13b is preferably in a concentric relationship, the annular positioning element 14 may also be referred to as a concentric ring.

In addition, the preload adjusting member 15 is also interposed between the two bearing sleeves 13a, 13b, and the inner diameter of the preload adjusting member 15 is larger than the outer diameter of the annular positioning member 14, as shown in FIG. The pressure adjusting elements 15 are all clamped to the two bearing sleeves 13a, 13b, and are pre-stressed The integral element 15 is disposed on the outer periphery of the annular positioning element 14, but the pre-stressing adjustment element 15 is not in contact with the annular positioning element 14.

Preferably, the components are fixed to each other in a screw-lock manner. Therefore, the bearing sleeves 13a and 13b and the pre-stressing adjusting component 15 respectively have a plurality of screw holes S1, and the positions of the screw holes S1 correspond to each other and are screwed. S2 locks the bearing sleeves 13a, 13b and the preload adjusting element 15 to each other. The preload adjusting member 15 is preferably made of rigid iron to provide better rigidity and toughness, to facilitate control of the pressure between the bearing sleeves 13a, 13b during the manufacturing process, and to increase the overall operational stability of the ball screw device 1. The bearing sleeve assembly A is formed by assembling the two bearing sleeves 13a, 13b, the annular positioning member 14, and the preload adjusting member 15.

Wherein, the bearing sleeves 13a, 13b and the annular positioning element 14 can be assembled after grinding to improve the mutual positioning accuracy, and the grinding processing method can be carried out according to the grinding processing method shown in FIG. FIG. 5 is a flow chart showing the steps of a method for grinding a bearing sleeve assembly according to an embodiment of the present invention. Referring to FIG. 5 and FIG. 4A and FIG. 4B , the method for grinding the bearing sleeve assembly of the bead screw device of the embodiment may include the following steps: grinding the side walls of the positioning groove in one of the two bearing sleeves respectively ( S10) grinding an outer surface of the annular positioning component (S20); assembling two bearing sleeves, an annular positioning component, and a pre-stressing adjustment component, wherein the annular positioning component is disposed in the positioning groove of the two bearing sleeves, and the outer surface is Abutting against a side wall of the inner positioning groove, and the annular positioning member is sandwiched between the two bearing sleeves (S30); grinding the inner wall surface of each bearing sleeve to form an inner ball groove (S40).

In step S10, the side walls 133a, 133b of the positioning grooves 132a, 132b in the two bearing sleeves 13a, 13b are respectively ground (as shown in Fig. 4A). In actual operation, the bearing sleeves 13a, 13b may be made of a metal material, and when formed in a mold, the overall structure of the bearing sleeves 13a, 13b is formed. The type is placed on the lathe to form the inner positioning grooves 132a, 132b, and the side walls 133a, 133b of the positioning grooves 132a, 132b in the mold forming are rough and uneven, thereby forming a flat structure by grinding. As shown in FIG. 4B, the side walls 133a, 133b include right angle wall faces of the inner positioning grooves 132a, 132b. In addition to the grinding side walls 133a, 133b, the outer surfaces 134a, 134b of the two bearing sleeves 13a, 13b may also be first ground (or simply ground), that is, the outer surface of the rear formed bearing sleeves 13a, 13b. The burrs of 134a, 134b are removed in a grinding manner to help reduce tolerances, and then, when assembled with the annular positioning element 14, the concentricity of the bearing sleeves 13a, 13b with the annular positioning element 14 is achieved. It should be noted that, in this embodiment, the two bearing sleeves 13a and 13b are not identical specifications, but in other embodiments, two identical bearing sleeves may be used. .

In step S20, the outer surface 141 of the annular positioning member 14 is ground such that the outer surface 141 of the annular positioning member 14 forms a flat structure, and the outer surface 141 includes the outer circumference and the two sides of the annular positioning member 14 (as shown in FIG. 4B). The bearing sleeves 13a, 13b and the annular positioning element 14 can be mated with each other. Of course, this creation does not exclude the grinding of the inner circumference of the annular positioning element 14 to further improve the accuracy.

In step S30, the two bearing sleeves 13a, 13b, the annular positioning element 14, and the preload adjusting element 15 are assembled to form the bearing sleeve assembly A. The annular positioning element 14 is disposed in the inner positioning grooves 132a and 132b of the two bearing sleeves 13a and 13b. For the description of the pre-stressing adjustment element 15 being sandwiched between the two bearing sleeves 13a and 13b, reference may be made to the foregoing, and no further details are provided herein. In step S10 and step S20, the outer surface 141 of the annular positioning member 14 and the side walls 133a, 133b of the inner positioning grooves 132a, 132b have been ground to a flat surface, so that the outer surface 141 of the annular positioning member 14 and the inner positioning concave The side walls 133a, 133b of the grooves 132a, 132b can accurately abut each other.

6 is a flow chart showing the steps of a method for grinding a bearing sleeve assembly according to another embodiment of the present invention. Referring to FIG. 4A, FIG. 4B and FIG. 6 simultaneously, the bearing sleeve 13a and the bearing sleeve 13b are mutually coupled by the annular positioning member 14. After the positioning, the step S32 is further included to grind the outer surfaces 134a, 134b of the two bearing sleeves 13a, 13b. Preferably, the outer surface 134a and the outer surface 134b are simultaneously ground. While the outer surfaces 134a, 134b include the outer periphery of the bearing sleeves 13a, 13b (as shown in Figure 4B), the outer surfaces 134a, 134b of the abrasive bearing sleeves 13a, 13b allow the bearing sleeves 13a, 13b to be combined with a machine or other object. At the same time, it can closely cooperate with each other, and at the same time, the grinding can avoid the step difference which may be generated by the fractional grinding, reduce the generation of the error, and achieve the high precision requirement. In addition, if the bearing sleeves 13a, 13b have been subjected to the base grinding before being combined into the bearing sleeve assembly A, and then through this fine grinding (relative to the base grinding, the grinding is combined into the bearing sleeve assembly A and the tolerance has been passed through the base grinding) The reduction, so the grinding is more detailed, so it is called), can further improve the overall accuracy of the device.

In step S40, the inner wall faces 135a, 135b of the bearing sleeves 13a, 13b are ground to form an inner ball groove 131a, 131b, respectively. Preferably, the inner wall faces 135a, 135b are simultaneously ground, and the same, while grinding After the combination of the split grinding bearing sleeves 13a, 13b can be avoided, the inner ball grooves 131a, 131b may have a height error, and after the bearing sleeves 13a, 13b and the nut 12 are assembled, the inner ball grooves 131a, 131b and The outer ball groove 121 of the nut 12 forms a step (as shown in FIG. 3).

FIG. 7 is a schematic view showing the installation manner of step S34 shown in FIG. 6. Please refer to FIG. 6 and FIG. 7 together with FIG. 4A. In actual operation, before grinding the inner wall surfaces 135a and 135b of the bearing sleeves 13a and 13b (step S40), step S34 may be further included to install the bearing. One of the sleeves 13a, 13b is end to a jig F, and the assembled two bearing sleeves 13a, 13b, the ring-shaped positioning element 14 and the pre-stressing adjustment element 15, that is, the fixed bearing sleeve assembly A, are fixed.

For example, in step S34, one end of the bearing sleeve 13b of the assembled assembly A assembled in step S30 is fixed by the jig F, and then proceeds to step S40. Or the end of the bearing sleeve 13b (or the bearing sleeve 13a) which is ground in step S32 is fixed by the jig F, and then proceeds to step S40, and the inner side of the two bearing sleeves 13a, 13b is protruded by the grinding tool, and simultaneously grinded inside. The wall faces 135a, 135b form inner ball grooves 131a, 131b. Since the bearing sleeve 13b is placed in the jig F after the outer surface 133b is finished, the calibration effect can be achieved, and the inner ball grooves 131a and 131b are formed by the post-grinding, and the inner ball grooves 131a and 131b can be further improved. Precision. Further, the accuracy of the inner ball grooves 131a and 131b is increased, and as shown in FIG. 3, the precision after combining with the ball grooves 121 other than the nut 12 can be further improved.

However, the above-mentioned grinding processing method is through the novel structure of the present invention, that is, the annular positioning member 14 is added and accommodated in the inner positioning grooves 132a, 132b of the bearing sleeves 13a, 13b to form the bearing sleeve assembly A, Only high-precision machining operations can be performed.

In addition, as shown in FIG. 1 to FIG. 3, in the present embodiment, the ball screw device 1 can further have two dustproof members 17 and two end caps 18, and is mounted on the nut 12. The end cap 18a further has a return path 181 which is coupled to the first ball passage to form a closed ball return path. In addition, a transmission connecting member P may be disposed outside one of the nuts 12 to receive power supply. Of course, in other embodiments, the transmission connector can also be assembled to other components, such as the end cap, which is not limited herein. In addition, the dustproof member 17 can prevent dust or debris from falling into the first ball passage or the second ball passage to affect the operation of the ball. In particular, the dust guard 17 can be located on the nut 12 and below the bearing sleeve 13 (away from the end of the annular positioning element 14) or, in other embodiments, at the junction of the nut 12 and the end cap 18. . Of course, the setting, the number, the size, or the size of the dustproof member 17, the end cover 18, and the transmission connecting member P are also not Restricted by creation.

Referring to FIG. 2 and FIG. 3 at the same time, the ball screw device 1 can further have a ball retainer 19 having a plurality of holes to assist in fixing the balls 16 accommodated in the second ball passage to avoid pre-assembly or disassembly. When the ball 19 is dropped, the ball 16 can be further fixed in position to reduce unnecessary shaking.

In addition, the present invention further provides a bearing sleeve assembly of a ball screw device, which is sleeved on a nut, and the bearing sleeve assembly comprises two bearing sleeves, an annular positioning component and a preload adjusting component. The bearing sleeves respectively have an inner positioning groove and an inner ball groove, and the inner ball groove is correspondingly arranged with a plurality of outer ball grooves of the nut. The annular positioning element is sandwiched between the two bearing sleeves, and the annular positioning element is received in the inner positioning groove. The preload adjusting component is sandwiched between the two bearing sleeves. For specific component structures and features, reference may be made to the foregoing, and details are not described herein.

In summary, according to the ball screw device and the bearing sleeve assembly of the present invention, by designing the positioning groove and the annular positioning component in the bearing sleeve, and accommodating the annular positioning component in the inner positioning groove, The relative position of the two bearing sleeves is fixed by the annular positioning element. The design of the bearing sleeve assembly enables the two bearing sleeves to be ground in the manner of the assembly, and the inner wall surface is ground to form an inner ball groove, so as to avoid the prior art two bearing sleeves being placed and used differently. Errors caused by fixtures or fractional grinding, resulting in uneven or uneven surfaces or joints after assembly. Therefore, the outer surface of the ball screw device formed by the present invention has high precision, and can be closely matched with the machine table or other objects to maintain the stability of the equipment during operation.

In addition, the design of the bearing sleeve assembly can further grind the inner wall surface of the two bearing sleeves to form the inner ball groove, which can also reduce the inner ball groove division of different bearing sleeves. The problem caused by the high degree of error caused by the grinding, thereby reducing the problem of forming a step difference between the internal components after the bearing sleeve and the nut are assembled.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of this creation shall be included in the scope of the appended patent application.

1‧‧‧Ball screw device

11‧‧‧ screw

111‧‧‧Spiral groove

12‧‧‧ Nuts

121‧‧‧Outer ball groove

13a, 13b‧‧‧ bearing sleeve

131a, 131b‧‧‧ inside ball groove

Positioning groove in 132a, 132b‧‧

14‧‧‧Ring positioning elements

15‧‧‧Preloading adjustment components

16‧‧‧ balls

17‧‧‧Dust-proof parts

18‧‧‧End cover

19‧‧‧Ball retainer

P‧‧‧Drive connector

S1‧‧‧ screw hole

S2‧‧‧ screws

Claims (10)

A bearing sleeve assembly of a ball screw device is sleeved on a nut, comprising: two bearing sleeves respectively having an inner positioning groove and an inner ball groove, the inner ball groove and a plurality of outer balls of the nut The groove is correspondingly disposed; an annular positioning component is sandwiched between the two bearing sleeves, and the annular positioning component is received in the inner positioning groove; and a pre-stressing adjustment component is sandwiched between the two bearing sleeves between. The bearing sleeve assembly of claim 1, wherein an outer surface of the annular positioning member abuts against a side wall of the inner positioning groove. The bearing sleeve assembly of claim 1, wherein the annular positioning member is received in the inner positioning grooves concentrically with the two bearing sleeves. The bearing sleeve assembly of claim 1, wherein the inner diameter of the preload adjusting member is larger than the outer diameter of the annular positioning member. The bearing sleeve assembly of claim 1, wherein the two bearing sleeves and the preload adjusting member are fixed to each other in a screw locking manner. A ball screw device comprising: a screw; a nut disposed on the screw, and a first ball passage between the nut and the screw, the outer surface of the nut having a plurality of outer ball grooves; A bearing sleeve assembly includes: two bearing sleeves respectively having an inner positioning groove and an inner ball groove, wherein the inner ball groove is corresponding to the outer ball grooves of the nut; An annular positioning component is interposed between the two bearing sleeves, and the annular positioning component is received in the inner positioning groove; and a pre-stressing adjustment component is sandwiched between the two bearing sleeves. The ball screw device of claim 6, wherein an outer surface of the annular positioning member abuts against a side wall of the inner positioning groove. The ball screw device of claim 6, wherein the annular positioning member is received in the inner positioning grooves concentrically with the two bearing sleeves. The ball screw device of claim 6, wherein the inner diameter of the preload adjusting member is larger than the outer diameter of the annular positioning member. The ball screw device of claim 6, wherein the two bearing sleeves and the preload adjusting member are fixed to each other in a screw locking manner.