JP4935636B2 - Tube presser and ball screw device using the same - Google Patents

Description

  The present invention relates to a tube presser for fixing a ball tube for circulating a ball of a ball screw device, and a ball screw device using the same.

  In the conventional ball screw device, a shaft raceway groove formed in a spiral shape on the outer peripheral surface of a screw shaft and a nut raceway groove opposed to the shaft raceway groove formed on an inner peripheral surface of a nut are screwed together via a plurality of balls. Then, both ends of the load path formed by the axial raceway groove and the nut raceway groove arranged opposite to each other are communicated by a communication path formed in the ball tube to form a circulation path, and one of the communication paths from the load path The ball is lifted and the ball in the circulation path is circulated while returning to the load path on the other side, and the ball tube with the communication path is inserted into the guide holes formed in the nuts at both ends. The end portions of the leg portions and the edge portions of the guide holes are elastically supported by coil springs each having an end portion fixed (see, for example, Patent Document 1).

Also, in a ball screw device having a similar configuration, a band-shaped metal plate is bent into a U shape, and a clamp member is provided with both ends extending horizontally outward to form mounting edges. The two coil springs are disposed between the head of the mounting bolt inserted through the hole of the mounting edge and the mounting surface of the nut, and the two coil springs elastically support the upper and lower sides of the mounting edge. (For example, refer to Patent Document 2).
Japanese Utility Model Publication No. 50-76280 (mainly, page 4, Fig. 4) Japanese Utility Model Publication No. 50-77664 (mainly, page 4-5, Fig. 6)

However, in the techniques of Patent Document 1 and Patent Document 2 described above, since the ball tube is elastically supported by the coil spring, the ball tube vibrates due to the vibration shock when the ball moves in the ball tube, There is a problem of increasing the noise of the ball screw device.
Moreover, since the structure is complicated, there is a problem that the cost of the ball screw device increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a tube presser capable of obtaining a stable high fixing force while suppressing the manufacturing cost.

In order to solve the above-described problems, the present invention provides a tube retainer for fixing a ball tube, wherein two side plates and a side plate are interposed between corner R portions having an arc radius smaller than the radius of the outer diameter of the ball tube. And connecting the outer diameter of the ball tube with three support portions of the two side plates and the top plate, and plastically deforming the support portion of the top plate when fixed. To do.

As a result, the present invention can stably support the outer diameter of the ball tube with the three support portions, can simplify the configuration of the tube presser and can suppress the manufacturing cost, and is stable. The effect that a high fixing force can be obtained is obtained.
Further, it is possible to reduce the noise of the ball screw device by suppressing the vibration caused by the vibration impact of the ball moving in the ball tube of the ball screw device using the tube presser by a high fixing force. .

  Embodiments of a tube presser according to the present invention and a ball screw device using the same will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing the ball screw device of the first embodiment, FIG. 2 is an explanatory view showing the upper surface of the tube presser of the first embodiment, and FIG. 3 is a view of the tube presser along the AA sectional line of FIG. It is explanatory drawing which shows a cross section.
In FIG. 1, 1 is a ball screw device.
Reference numeral 2 denotes a ball as a rolling element of the ball screw device 1, which is a sphere made of a steel material such as alloy steel.

Reference numeral 3 denotes a screw shaft of the ball screw device 1, which is a rod-shaped member made of a steel material such as alloy steel, and an axial raceway groove 4 having an arc-shaped cross-section is spirally formed with a predetermined lead on the outer peripheral surface thereof. Is formed.
Reference numeral 5 denotes a nut of the ball screw device 1, which is a cylindrical member made of a steel material such as alloy steel, and the inner peripheral surface thereof has a nut raceway groove 6 having an arcuate cross-sectional shape facing the shaft raceway groove 4. Is formed with the same lead as the shaft raceway groove 4, and a flange portion 7 for fixing the nut 5 to a moving table of a mechanical device (not shown) with a bolt or the like is provided at one end portion of the outer peripheral portion thereof. Yes.

  Reference numeral 8 denotes a ball tube, which is made of a steel material or the like and is a tube bent in a substantially U shape having an inner diameter through which the ball 2 can pass and having bent portions at two locations. The cylindrical leg portions 8a at both ends of the fitting holes 5b that reach the nut raceway grooves 6 provided on the flat surface 5a that are notched parallel to the axial direction are engaged with the nut raceway grooves 6, A return portion 8b between the leg portions 8a is fixed to the nut 5 by a tube presser 11 (described later) fastened by a bolt 9 to a screw hole formed in the flat surface 5a of the nut 5.

As a result, both ends of the spiral load path formed by the shaft raceway groove 4 and the nut raceway groove 6 are communicated by a communication path formed as the inner diameter of the ball tube 8 so that a circulation path through which the ball 2 circulates is obtained. By forming and rotating the screw shaft 3, the nut 5 reciprocates in the axial direction of the screw shaft 3, and the rotational motion of the screw shaft 3 is converted into the linear motion of the nut 5.
The circulation path of the present embodiment is formed at two locations in the axial direction of the screw shaft 3, and the directions of the return portions 8b of the respective ball tubes 8 are formed in different directions (see FIG. 2).

  The tube presser 11 of this embodiment is manufactured by bending a strip-shaped steel plate or the like, and as shown in FIGS. 2 and 3, each of the two side plates 12 inclined inward toward the top plate 14 and the side plates 12. A tube support portion 15 that is a gate-shaped groove formed in a trapezoidal shape with a top plate 14 that connects one end portion of the ball tube 8 via a corner R portion 13 having an arc radius smaller than the radius of the outer diameter of the ball tube 8; The inner surface of the side plate 12 and the top plate 14 of the tube support portion 15 is formed above the flat surface 5a of the nut 5 with a return portion 8b of the ball tube 8 in a predetermined group. A diameter smaller than the outer diameter Da of the return portion 8b when installed at the height Ht (the height from the plane 5a of the nut 5 at the center C of the return portion 8b of the ball tube 8 shown in FIG. 3). So that the circle with It is formed.

Thereby, when the ball tube 8 is fitted to the fitting hole 5b of the nut 5 with the leg portions 8a on both sides and assembled to the nut 5 with the tube presser 11, as shown in FIG. It is stably supported by a total of three support portions consisting of a support portion on the inner surface of the two side plates 12 supporting the side of the outer diameter Da of 8b and a support portion on the inner surface of the top plate 14 supporting the upper side. .
In this case, the inclined inner surfaces of the two side plates 12 are elastically deformed by the wedge effect by absorbing manufacturing errors and outer diameter errors (referred to as assembly errors) of the assembly height Ht of the ball tube 8, While the inner surface of the top plate 14 is supported by the elastic deformation of the corner R portion 13, it itself plastically deforms and absorbs the assembly error.

For this reason, the yield point load of the tube presser 11 is set to be lower than the yield point load in the crushing direction of the ball tube 8.
2 is the same as the cross-sectional shape on the right side shown in FIG.
The outer diameter Da of the ball tube 8 on which the above inscribed circle is based is the lower limit of the manufacturing tolerance of the outer diameter Da of the ball tube 8, and the predetermined assembly height Ht is determined by the lower limit of each dimensional tolerance related to assembly. It is desirable to set the lower assembly height Ht to be formed. In this way, the ball tube 8 can be stably supported by the tube retainer 11 of the present embodiment regardless of the manufacturing tolerance of the ball tube 8 or the like.

  As described above, the tube retainer 11 of the present embodiment connects the two side plates 12 inclined inward and the side plates 12 via the corner R portion 13 having an arc radius smaller than the radius of the outer diameter of the ball tube. A top-shaped tube support portion 15 formed by the top plate 14 and when the ball tube 8 is assembled at a predetermined assembly height Ht, the inner surface of the tube support portion 26 is the ball tube. Since the ball tube 8 is formed so as to be inscribed in a circle having a diameter smaller than the outer diameter Da of 8, the outer diameter Da of the ball tube 8 can be reduced by the wedge effect of the two side plates 12 and the plastic deformation of the top plate 14. While absorbing the assembly error, it can be stably supported by the three support portions by the respective inner surfaces, the structure of the tube presser 11 can be simplified, and the manufacturing cost can be suppressed and stable. High fixing force was can be obtained.

  As described above, in this embodiment, the top plate that connects the two side plates and the side plate to the tube presser for fixing the ball tube via the corner R portion having an arc radius smaller than the radius of the outer diameter of the ball tube. And the ball tube outer diameter is supported by the three support portions of the two side plates and the top plate, thereby stabilizing the outer diameter Da of the ball tube with the three support portions with one component. Thus, the structure of the tube presser can be simplified to reduce the manufacturing cost, and a stable high fixing force can be obtained.

In addition, it is possible to reduce the noise of the ball screw device by suppressing the vibration due to the vibration impact of the ball moving in the ball tube of the ball screw device using the tube presser by a high fixing force.
Furthermore, by forming the side plate of the tube retainer so as to incline inward toward the top plate, the side of the outer diameter of the ball tube is stabilized while absorbing the assembly error by the wedge effect of the two side plates. Can be supported.

  Furthermore, since the support portion of the top plate of the tube presser is plastically deformed when fixed, the upper portion of the outer diameter of the ball tube can be stably supported while absorbing the assembly error.

FIG. 5 is an explanatory view showing the upper surface of the fixing member of the second embodiment, and FIG. 6 is an explanatory view showing a cross section of the tube presser along the BB cross section line of FIG.
In addition, the same part as the said Example 1 attaches | subjects the same code | symbol, and abbreviate | omits the description.
In FIG. 5, reference numeral 21 denotes a fixing member, which is formed by cutting a steel material or the like into a prismatic shape by cutting, and is formed in the middle of the guide groove 22 for loosely fitting the outer diameter Da of the return portion 8 b of the ball tube 8. A storage portion 24 for storing the tube retainer 23 of the present embodiment, a stepped bolt hole 25 for inserting a bolt 9 for fastening the fixing member 21 into a screw hole formed in the flat surface 5a of the nut 5; Is formed.

  As shown in FIG. 6, the tube presser 23 of the present embodiment is manufactured by bending a steel plate or the like, and between the two side plates 12 inclined to the inside, as in the first embodiment. A trapezoidal tube-shaped tube support portion 26 is formed with the top plate 14 connected via the corner R portion 13, and the side plate 12 of the tube support portion 26 and the inner surface of the top plate 14 are flat surfaces of the nut 5. When the return portion 8b of the ball tube 8 is installed at a predetermined assembly height Ht above 5a, a circle having a diameter smaller than the outer diameter Da of the return portion 8b is formed so as to be inscribed, and the top plate Above 14, an escape portion 27 is provided for securing a deformation allowance due to plastic deformation of the top plate 14.

Further, the depth of the storage portion 24 of the fixing member 21 is formed to a depth obtained by subtracting a predetermined pressing allowance from the total height of the tube presser 23.
Thereby, when the ball tube 8 is assembled to the nut 5 by the fixing member 21 in which the tube pressing member 23 is accommodated in the accommodating portion 24 by fitting the leg portions 8a on both sides into the fitting holes 5b of the nut 5. As shown in FIG. 7, the support plate on the inner surface of the two side plates 12 of the tube presser 23 pressed in the height direction by the storage portion 24 supports the side of the outer diameter Da of the return portion 8 b, and the top plate The upper part is supported by the support part on the inner surface of 14, and is supported stably by a total of three support parts.

In this case, the inclined inner surfaces of the two side plates 12 are elastically deformed by absorbing the assembly error of the ball tube 8 by the wedge effect, and the inner surface of the top plate 14 is supported by the elastic deformation of the corner R portion 13. , Itself is plastically deformed to absorb assembly errors.
As described above, the tube retainer 23 of this embodiment connects the two side plates 12 inclined inward and the side plates 12 via the corner R portion 13 having an arc radius smaller than the radius of the outer diameter of the ball tube. A top-shaped tube support portion 26 formed with the top plate 14 is assembled to the nut 5 while being housed in the housing portion 24 of the fixing member 21, and the ball tube 8 has a predetermined assembly height. Since the inner surface of the tube support portion 26 is inscribed in a circle having a smaller diameter than the outer diameter Da of the ball tube 8 when assembled to the height Ht, the outer diameter Da of the ball tube 8 is While the assembly effect is absorbed by the wedge effect of the two side plates 12 and the plastic deformation of the top plate 14, it can be stably supported by the three support portions by the respective inner surfaces, and the structure of the tube presser 23 can be configured. Simplification It is possible to suppress the manufacturing cost Te, it is possible to obtain a stable and high fixing force.

Further, it is possible to reduce the noise of the ball screw device 1 by suppressing the vibration due to the vibration impact of the ball 2 moving in the ball tube 8 of the ball screw device 1 using the tube presser 23 with a high fixing force. it can.
As described above, in this embodiment, the tube presser having the same configuration as in the first embodiment is housed in the housing portion of the fixing member so as to fix the ball tube. Similar effects can be obtained.

FIG. 8 is an explanatory view showing the appearance of the tube presser of Example 3, and FIG. 9 is an explanatory view showing a cross section of the tube presser.
FIG. 9 is a cross-sectional view similar to that of FIG. Further, the same parts as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In FIG. 8, reference numeral 30 denotes a tube presser, which is made of a soft material such as a resin material or a soft metal material as in the first embodiment, and has a corner R portion 13 between two side plates 12 and the side plates 12. A tube support portion 34 having a plurality of ribs 32 formed on the inner surface of a gate-shaped frame 31 formed in a rectangular shape with the top plate 14 connected via the fixing plate 21 as shown in FIG. When the outer surface of the frame 31 is fitted and attached to the storage portion 24, the inner surface of the rib 32 of the tube support portion 34 provided on the side plate 12 and the top plate 14 is above the flat surface 5a of the nut 5. In addition, when the return portion 8b of the ball tube 8 is installed at a predetermined assembly height Ht, a circle having a diameter smaller than the outer diameter Da of the return portion 8b is formed so as to be inscribed.

  Thus, when the ball tube 8 is assembled to the nut 5 by the fixing member 21 in which the leg portions 8a on both sides are fitted into the fitting holes 5b of the nut 5 and the tube presser 30 is accommodated in the accommodating portion 24. As shown in FIG. 10, the two side plates 12 of the tube presser 30 fitted to the storage portion 24 and the support portion on the inner side surface of the rib 32 provided on the top plate 14, the outer diameter Da of the return portion 8 b. The sides and the upper side are supported, and are stably supported by a total of three support portions.

In this case, the inner surfaces of the ribs 32 of the two side plates 12 are elastically deformed by absorbing the assembly error of the ball tube 8, and the inner surfaces of the ribs 32 of the top plate 14 are plastically deformed to absorb the assembly error. To do.
The material of the soft material forming the tube presser 30 and the number and width of the ribs 32 are such that the ball tube 8 does not cause harmful deformation in the support portion of the rib 32 provided on the top plate 14. May be determined so as to be within a range in which the soft material is elastically deformed without plastic deformation at the support portion of the rib 32 provided on the side plate 12.

  As described above, the tube retainer 30 of the present embodiment includes the two side plates 12 provided with the ribs 32 on the inside, and the corner R portion 13 having an arc radius smaller than the radius of the outer diameter of the ball tube between the side plates 12. And the top plate 14 provided with the ribs 32 to be connected to each other, and has a portal tube support portion 34 formed in the housing portion 24 of the fixing member 21 and assembled to the nut 5. When the tube 8 is assembled at a predetermined assembly height Ht, the inner surface of the rib 32 of the tube support portion 34 is formed so as to be inscribed in a circle having a diameter smaller than the outer diameter Da of the ball tube 8. Therefore, the outer diameter Da of the ball tube 8 is reduced at three locations by the respective inner surfaces while absorbing assembly errors by elastic deformation of the ribs 32 of the two side plates 12 and plastic deformation of the ribs 32 of the top plate 14. At the support Can be constant to support, it is possible to suppress the manufacturing cost by simplifying the structure of the tube pressing member 30, it is possible to obtain a stable and high fixing force.

Further, it is possible to reduce the noise of the ball screw device 1 by suppressing the vibration due to the vibration impact of the ball 2 moving in the ball tube 8 of the ball screw device 1 using the tube presser 30 with a high fixing force. it can.
As described above, in the present embodiment, the tube retainer provided with a plurality of ribs on the inner surface of the portal frame is housed in the housing portion of the fixing member to fix the ball tube. The same effect as in the second embodiment can be obtained.

In each of the above-described embodiments, the ball tube is described as a single tube. However, as shown in FIG. 11, the ball tube 40 is divided into half pieces substantially along the moving direction of the ball. The same effect can be obtained even when the ball tube 40 is a combination of 40a and 40b.
In each of the above embodiments, the side plate of the tube retainer is inclined inward to form the tube support part in a trapezoidal cross-sectional shape. However, the cross-sectional shape of the tube support part is formed in a rectangular shape. May be. Even in this case, when the ball tube is fixed, the side plate is pushed and inclined, and the side of the ball tube can be supported by the wedge effect, and the same effect as the above embodiment can be obtained. it can.

Further, in each of the above embodiments, the directions of the return portions of the two ball tubes are described as being formed in different directions. However, the directions may be the same, and there may be one or more ball tubes. Also good.
Further, in each of the above embodiments, the screw shaft of the ball screw device is rotated and the nut is moved in the axial direction. However, in the ball screw device of the type in which the nut is rotated and the screw shaft is moved in the axial direction. The same effect can be obtained even when the present invention is applied.

Explanatory drawing which shows the ball screw apparatus of Example 1. Explanatory drawing which shows the upper surface of the tube presser of Example 1. Explanatory drawing which shows the cross section of the tube presser along the AA cross section line of FIG. Explanatory drawing which shows the assembly | attachment state of the ball tube of Example 1. FIG. Explanatory drawing which shows the upper surface of the fixing member of Example 2. Explanatory drawing which shows the cross section of the tube presser along the BB cross section line of FIG. Explanatory drawing which shows the assembly | attachment state of the ball tube of Example 2. FIG. Explanatory drawing which shows the external appearance of the tube presser of Example 3. Explanatory drawing which shows the cross section of the tube presser of Example 3. Explanatory drawing which shows the assembly | attachment state of the ball tube of Example 3. Explanatory drawing which shows the other form of a ball tube

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ball screw apparatus 2 Ball 3 Screw shaft 4 Axis raceway groove 5 Nut 5a Plane 5b Fitting hole 6 Nut raceway groove 7 Flange part 8, 40 Ball tube 8a Leg part 8b Return part 9 Bolt 11, 23, 30 Tube presser 12 Side plate 13 Corner R portion 14 Top plate 15, 26, 34 Tube support portion 16 Bolt hole 17 Mounting portion 21 Fixing member 22 Guide groove 24 Storage portion 25 Stepped bolt hole 27 Escape portion 31 Frame body 32 Rib 40a, 40b Split piece

Claims (3)

In the tube presser that fixes the ball tube,
Providing two side plates and a top plate connecting between the side plates via a corner R portion having an arc radius smaller than the outer radius of the ball tube;
A tube retainer characterized in that the outer diameter of the ball tube is supported by three support portions of the two side plates and the top plate, and the support portion of the top plate is plastically deformed when fixed . In claim 1,
The tube presser, wherein the side plate is inclined inward toward the top plate. Ball screw device characterized by using the tube retainer of claim 1 or claim 2.