JP5428290B2 - Ball screw integrated linear motion guide unit - Google Patents

Description

The present invention relates to a ball Lumpur screw integrated linear guide unit.

As a conventional example of a ball Lumpur screw integrated linear guide unit, for example, it includes a table transfer device described in Patent Document 1. In the device of this document, a ball screw having a screw shaft and a nut, a linear guide having a guide rail and a slider are integrated, and a ball screw hole (nut) is directly formed in the slider, and is perpendicular to the longitudinal direction of the guide rail. The cross section is concave (U-shaped), and the slider is guided along the axial direction of the screw shaft while being accommodated in the concave portion.

  The guide rail of this device has a rolling surface that constitutes a rolling passage of the rolling element on the inner side surface of each sleeve portion arranged to face each side surface of the slider. The slider has a rolling surface that is disposed opposite to the rolling surface of the guide rail and constitutes the rolling passage, a return passage of the rolling element, and a direction changing path that communicates the return passage and the rolling passage. Have. The rolling element is a ball, has two-to-four rows of rolling passages, and the intersection of the load action lines of the ball rows rolling on the two rows of rolling passages of each sleeve is the rolling passage in the width direction. It exists inside.

Patent Document 2 and Patent Document 3 below describe a ball screw-integrated linear motion guide unit in which rollers are incorporated as rolling elements. By using a roller as a rolling element, load capacity and rigidity can be increased while ensuring weight reduction and compactness compared to the case of using a ball.
The ball screw-integrated linear motion guide unit described in Patent Document 2 has two-to-four rows of rolling passages, and has a load acting line of a roller row that rolls in two rows of rolling passages of each sleeve portion. The intersection exists inside the rolling passage in the width direction. However, the ball screw is formed as a separate member from the inner rail (slider) and is fixed to the recess of the inner rail. That is, the ball screw nut is not directly formed on the slider.

In the ball screw integrated linear motion guide unit described in Patent Document 3, a female thread portion (slider nut) of the bearing block is formed by insert molding.
Japanese Patent Publication No.8-18209 FIG. 24 of JP-A-2002-227839 Japanese Patent No. 3431354

An object of the present invention, rolling Oite the ball Lumpur screw integrated linear guide unit using rollers as the moving object, cost and without problems productivity decreases, to be secured in weight and compact That is.

In order to solve the above-mentioned problems, the present invention provides a guide rail having a U-shaped cross section, a slider disposed in a U-shaped recess of the guide rail, and between the guide rail and the slider. A plurality of rolling elements arranged in the slider, a nut formed in parallel with the guide rail in the slider, a screw shaft passing through the nut, and a ball screw disposed between the nut and the screw shaft. And the guide rail has a rolling surface that constitutes a rolling path of the rolling element on the inner side surface of each sleeve portion arranged to face each side surface of the slider, The slider is disposed opposite to the rolling surface of the guide rail and constitutes the rolling passage, a return passage of the rolling element, and a direction changing path that communicates the return passage and the rolling passage. The rolling elements are rollers, and each sleeve has two Intersection of roller rows of the load action line rolling the rolling path of the is present on the inner side of the said rolling path in a width direction, wherein the nut is formed directly on the slider, said slider, said rolling surface are those helical groove of the nut are formed in separate steps, during said rolling surface and said roller is a specification no clearance, the ball screw unit is a specification in which a gap, before Symbol screw A ball screw integrated linear motion guide unit is provided in which a slider is fed by a ball screw mechanism by the operation of a shaft and the slider is guided by a linear guide mechanism so that the slider linearly moves relative to a guide rail.

Thus, according to the ball screw-integrated linear motion guide unit of the present invention, the intersection of the load action lines of the roller trains rolling the two rows of rolling passages of each sleeve portion is the rolling passage in the width direction. Because it exists more inside (DF contact structure), it is superior in alignment than the case where the intersection is outside the rolling passage in the width direction (DB contact structure) Also, the force generated by applying a twisting force is small. Therefore, even if a relative positional shift occurs between the roller rolling surface and the nut spiral groove (ball screw ball rolling groove) formed in separate processes with respect to the slider, It is possible to suppress a decrease in life due to the application of force. Accordingly, there is no need to make the relative positional accuracy of the roller rolling surface and the spiral groove of the nut high with respect to the slider, so that problems of cost increase and productivity reduction do not occur.

In addition, the intersection of the load acting lines of the roller rows that roll in the two rows of rolling passages of each sleeve is present inside the rolling passage in the width direction (DF contact structure), The roller return passage can be arranged compactly in the vertical direction in the slider.
Moreover, since the nut which comprises a ball screw is directly formed in the slider, the dimension of a slider can be made small compared with the nut formed with the slider and another member. Further, the cost is lower than that in which the nut is formed on the slider by insert molding.

According to the ball screw integrated linear motion guide unit of the present invention, by using rollers as the rolling elements, the load capacity and rigidity of the ball screw integrated linear motion guide unit can be increased. By forming directly on the slider, there is no problem of cost increase or productivity reduction, and it is possible to ensure weight reduction and compactness.

According to the ball screw integrated linear motion guide unit of the present invention, without Oite, in cost and lower productivity problems on ball Lumpur screw integrated linear guide unit using rollers as rolling elements, lightweight And it is possible to ensure compactness.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a plan view showing a ball screw integrated linear motion guide unit corresponding to an embodiment of the present invention. FIG. 2 is a side view of FIG. 3 is a cross-sectional view taken along the line AA in FIG. 4 is a cross-sectional view taken along the line BB of FIG.
The ball screw integrated linear motion guide unit includes a guide rail 1, a slider 2, a screw shaft 3, a ball 4, and rollers 5.

The cross section perpendicular to the longitudinal direction of the guide rail 1 has a U-shape (U-shape) with the opening side up, and the slider 2 is housed in the recess 11. In the guide rail 1, a rolling surface 12 a that constitutes a rolling path of the roller 5 is formed on the inner surface of each sleeve portion 12 that is disposed to face each side surface of the slider 2. The upper and outer portions 12b of the respective sleeve portions 12 are chamfered larger than usual.
The slider 2 is formed with a female screw (nut) 21 penetrating in parallel with the guide rail 1. The nut 21 is formed by directly machining a spiral groove in the slider 2.

The screw shaft 3 passes through the nut 21, and the ball 4 is disposed between the screw shaft 3 and the screw shaft 3 in the nut 21. Both ends in the length direction of the screw shaft 3 are rotatably supported at both ends in the longitudinal direction of the guide rail 1. One end of the screw shaft 3 in the length direction (the portion protruding to the right end in FIGS. 1 and 2) is attached to the motor in use.
The slider 2 is divided into a slider body 2A, an end cap 2B, a lubricating component 2C, and a side seal 2D in the linear motion direction. A direction changing path is formed in the end cap 2B.

  As shown in FIG. 4, the lubricating component 2 </ b> C is formed by fixing sealing members 71 </ b> A and 71 </ b> B in which a polyethylene porous body is impregnated with lubricating oil to a mounting plate 72. The semicircular seal member 71 </ b> A is disposed at the peripheral portion of the screw shaft 3, and the substantially trapezoidal seal member 71 </ b> B is disposed so as to contact the rolling surface 12 a of the sleeve portion 12 of the guide rail 1. When fixed between the side seal 2D and the end cap 2B, the seal member 71A contacts the screw shaft 3 with an appropriate pressure by a spring coil, and the seal member 71B rolls with an appropriate pressure by a leaf spring 73. Contact surface 12a.

  A rolling surface 22a is formed on each side surface of the slider body 2A at a position facing the rolling surface 12a of the guide rail 1. These opposing rolling surfaces 12 a and 22 a constitute a rolling path of the roller 5. This rolling passage has two to four rows, and the intersection C of the load acting lines L1 and L2 of the roller row rolling on the two rows of rolling passages of each sleeve 12 is located inside the rolling passage in the width direction. Existing. A horizontal line LC passing through the intersection C is disposed below the center height (line L3) of the screw shaft 3 by a dimension K. The center height of the screw shaft 3 (line L3) is about ½ of the height H of the entire ball screw integrated linear motion guide unit. The angle (contact angle) between the horizontal line LC and the load action lines L1 and L2 is 45 °. A return passage 51 is also formed in the slider body 2A.

  In the guide rail 1, a through hole 15 for inserting a mounting bolt is formed in a bottom portion 13 sandwiched between both sleeve portions 12. The through hole 15 is formed at a boundary position with each sleeve portion 12 of the bottom portion 13 in the width direction. A meat stealing portion 16 is formed between the through holes 15 on the bottom surface of the bottom portion 13 of the guide rail 1. The guide rail 1 is in contact with the table (attached surface) 6 at a position other than the meat stealing portion 16.

  The guide rail 1 of this linear motion device is fixed to the table 6 by bolting using the attachment holes 15. Then, by operating the motor to rotate the screw shaft 3, the slider is passed through the ball screw mechanism (nut 21, screw shaft 3, ball 4) and the linear guide mechanism (rolling surfaces 12a, 22a, rollers 5). 2 moves along the axial direction with respect to the guide rail 1.

According to the ball screw-integrated linear motion guide unit of this embodiment, the intersection C of the load action lines of the roller rows that roll in the two rows of the rolling passages of each sleeve portion 12 is in the width direction. (DF contact structure) is excellent in alignment and the force generated by applying a twisting force is small. For this reason, as a result of forming the rolling surface 22a of the roller 5 and the spiral groove of the nut 21 (rolling groove of the ball screw ball) in separate steps with respect to the slider 2, a relative displacement occurs between the two. However, it is possible to suppress a decrease in the life due to the application of the twisting force. Therefore, since it is not necessary to make the relative positional accuracy of the rolling surface 22a of the roller 5 and the spiral groove of the nut 21 high with respect to the slider 2, there is no problem of cost increase or productivity reduction. In addition, since the contact angle is 45 °, it is possible to receive loads in the vertical direction and the horizontal direction with a good balance.

Further, in the ball screw integrated linear motion guide unit of this embodiment, the upper and outer portions 12b of the respective sleeve portions 12 are chamfered larger than usual. Since the thickness of the upper portion of the sleeve portion 12 has little influence on the deformation that the sleeve portion 12 opens in the width direction, the sleeve portion 12 opens in the width direction by chamfering the upper and outer portions 12b of the sleeve portion 12 greatly. The guide rail 1 can be reduced in weight while suppressing deformation.

In the ball screw integrated linear motion guide unit of this embodiment, the center height (line LC) of the two rows of rolling passages is disposed below the center height (line L) of the screw shaft 3. ing. That is, the positions of the rolling surfaces 12 a and 22 a are arranged near the boundary position with the bottom portion 13 of the sleeve portion 12. Therefore, even when the slider 2 receives a load and the sleeve 12 of the guide rail 1 is opened and deformed, the rolling surfaces 12a and 22a caused by the inclination of the rolling surfaces 12a and 22a are formed at the contact portions with the contact portion 5. It is possible to minimize the unevenness of the surface pressure distribution and the life reduction due to edge loading.
Further, according to the ball screw integrated linear motion guide unit of this embodiment, the nut 21 constituting the ball screw is directly formed on the slider 2, and therefore the nut 21 is formed as a separate member from the slider 2. Compared with, the size of the slider 2 can be reduced. Therefore, the weight reduction and compactness obtained by using the roller 5 as a rolling element are ensured. Further, the cost can be reduced in comparison with the case where the nut 21 is formed on the slider 2 by insert molding.

Further, according to the ball screw integrated linear motion guide unit of this embodiment, since the lubricating component 2C is incorporated in the slider 2, the lubricating performance is ensured for a long period of time, and the sealing performance of the side seal 2D is also long-term. Since it is secured across, the life is extended.
The linear guide portion has a specification with no gap between the rolling surfaces 12a and 22a and 5 in order to prevent the workpiece mounted on the slider 2 from rattling, but the ball screw portion has a slight gap. By making it a specification, it may be made to move smoothly with a light frictional force, or it may be a light preload specification in applications where repeated positioning accuracy is important.

It is a top view which shows the ball screw integrated linear motion guide unit equivalent to one Embodiment of this invention. It is a side view of FIG. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG.

DESCRIPTION OF SYMBOLS 1 Guide rail 11 Recessed part 12 Sleeve part 12a Rolling surface of guide rail 12b Upper and outer part of sleeve part 13 Bottom part 15 Mounting hole 16 Meat stealing part 2 Slider 2A Slider body 2B End cap 2C Lubricating part 2D Side seal 21 Nut 22a Slider Rolling surface 3 Screw shaft 4 Ball 5 Roller 6 Table (Mounted surface)
71A, 71B Seal member 72 Mounting plate 73 Leaf spring

Claims (1)

A guide rail having a U-shaped cross section;
A slider disposed in a U-shaped recess of the guide rail;
A plurality of rolling elements disposed between the guide rail and the slider;
A nut formed in the slider in parallel with the guide rail;
A screw shaft passing through the nut;
A ball constituting a ball screw disposed between the nut and the screw shaft;
Have
The guide rail has a rolling surface that constitutes a rolling passage of the rolling element on an inner surface of each sleeve portion disposed to face each side surface of the slider,
The slider is disposed opposite to the rolling surface of the guide rail and constitutes the rolling passage, a return passage of the rolling element, and a direction changing path that communicates the return passage and the rolling passage. Have
The rolling element is a roller, and the intersection of the load acting lines of the roller rows that rolls in the two rows of rolling passages of each sleeve portion exists inside the rolling passage in the width direction,
The nut is formed directly on the slider;
In the slider, the rolling surface and the spiral groove of the nut are formed in separate steps,
It is a specification with no gap between the rolling surface and the roller, the ball screw part is a specification with a gap,
A ball screw integrated linear motion guide unit in which the slider is fed by a ball screw mechanism by the operation of the screw shaft and the slider is guided by a linear guide mechanism so that the slider linearly moves relative to the guide rail.

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