JP4953442B2 - Linear motion bearing device - Google Patents

Description

  The present invention relates to a linear motion bearing device, and more particularly to correction of a positional deviation of a retainer interposed between a shaft and a sleeve inserted through the shaft.

Conventionally, as shown in FIG. 6 , the linear motion bearing device 100 includes a cylindrical retainer 130 holding a rolling element 131 in a gap S between a shaft portion 120 and a sleeve 110 inserted through the shaft portion 120. The moving body 130 is brought into rolling contact with the outer peripheral surface of the shaft portion and the inner peripheral surface of the sleeve so that the linear motion reciprocation between the shaft portion 120 and the sleeve 110 is smoothly performed. At this time, the retainer 130 moves, for example, by a half of the movement amount (L) of the shaft portion 120 (L / 2) as the shaft portion 120 and the sleeve 110 move relative to each other, but actually the rolling element 131 is moved. In order to cause a minute slip, the position may gradually shift in the axial direction.

Therefore, in the conventional linear bearing device 100, the pin 140 is attached outwardly to the side wall of the retainer 130, the recessed portion 111 is formed on the inner peripheral surface of the sleeve, and the pin 140 is disposed in the recessed portion 111. In addition, a spring 150 that urges the pin 140 up and down is disposed to prevent the retainer 130 from being displaced in the linear motion direction (Patent Document 1).
JP 2002-96298 A

  However, the conventional linear motion bearing device 100 has a problem that the strength of the sleeve 110 is weakened because the recess 110 is provided in the sleeve 110. As a result, the pressing force (preload) applied to each rolling element 131 from the sleeve inner peripheral surface varies, and it becomes difficult to maintain the linear motion accuracy with high accuracy.

  Further, for example, if the number of the recesses 111 is increased in the circumferential direction in order to increase the number of the springs 150, or if the length of the recesses 111 is increased to ensure the length of the springs 150, the sleeve 110 may be deformed. .

  In view of the above circumstances, an object of the present invention is to provide a linear motion bearing device that enables correction of a positional deviation of a retainer without causing a decrease in strength of a sleeve.

The linear motion bearing device according to the present invention includes:
A linear motion bearing device in which a cylindrical retainer is disposed in a gap between a shaft portion and a sleeve fitted to the shaft portion, and a rolling element is held by the retainer,
On the side wall of the retainer, an arrangement space for a coil spring serving as an elastic body is provided,
The arrangement space is opened to at least one of the side wall end faces in both openings of the retainer,
A push pin that is inserted through the entire area of the coil spring disposed in the arrangement space and engages one end of the coil spring is provided, and the push pin protrudes from the side wall end surface,
The protruding tip of the push pin is disposed so as to be able to contact a lid member attached to the opening of the sleeve or a large-diameter convex portion provided on the outer peripheral surface of the shaft portion.

With the above configuration, when the retainer is moved in the axial direction along with the relative linear motion reciprocation between the shaft portion and the sleeve, the protruding tip of the push pin comes into contact with the cover member of the sleeve or the convex portion of the shaft portion. Thus, the elastic body in the arrangement space is compressed. When the external force applied to the retainer is released and the retainer is stopped from moving in the axial direction, the retainer is returned to the original position by the biasing force of the elastic body. Accordingly, it is possible to correct the positional deviation so that the retainer is automatically returned to the original reference position.
Further, since the push pin is inserted through the entire area of the coil spring, the coil spring is guided by the push pin and compressed without buckling. Therefore, it is possible to surely correct the displacement of the retainer by the biasing force of the coil spring in the axial direction.

The retainer is formed in a polygonal cylinder, and a bent portion of a side wall of the retainer has a pocket portion serving as an arrangement space for arranging the coil spring, a convex portion formed on the wall, and an axis at the convex portion. An insertion hole penetrating in the direction and communicating with the pocket portion and through the push pin is provided,
It is desirable that one end of the coil spring is locked to a locking member attached to the push pin, and the other end is locked to the peripheral edge of the insertion hole.
As a result, the retainer can be corrected for misalignment without reducing the strength of the entire retainer.

  According to the linear motion bearing device of the present invention, the retainer is corrected for displacement so that it automatically returns to the original reference position, so that there is no displacement with respect to the sleeve and the shaft portion. Accordingly, there is no deviation in the positional relationship between the rolling element held by the retainer, the shaft portion, and the sleeve, and the relative linear motion reciprocation between the shaft portion and the sleeve can be performed stably and smoothly. . In addition, since it is not necessary to form a recess in the sleeve as in the prior art, it is possible to correct the displacement of the retainer without reducing the strength of the sleeve. As a result, it is possible to correct the displacement of the retainer while maintaining the linear motion accuracy with high accuracy.

Embodiments of the present invention will be described below with reference to the drawings.
( Reference example )
As shown in FIGS. 1 (a) and 1 (b), in a linear motion bearing device 1 according to a reference example , a cylindrical sleeve 3 having a shaft insertion hole 30 having a polygonal cross section is inserted into a polygonal shaft portion 2. A retainer 5 made of a polygonal cylinder holding a large number of rollers (rolling elements) 4 is disposed in the gap S between the shaft portion 2 and the sleeve 3. The shaft portion 2 has a hexagonal outer peripheral surface, and the inner peripheral surface of the sleeve 3 is also formed in a hexagonal shape in accordance with the outer peripheral surface of the shaft portion 2. Ring-shaped lid members 35 a and 35 b are attached to both openings of the sleeve 3.

  The retainer 5 is made of, for example, resin or the like, and is formed of a hexagonal cylindrical body in accordance with the shape of the gap S between the shaft portion 2 and the sleeve 3. A roller 4 is provided on each flat portion of the side wall 50. A large number of holes 51 for holding are arranged in parallel. Accordingly, the large number of rollers 4 held by the retainer 5 are arranged in series corresponding to the positions of the respective flat surface portions 21 on the outer peripheral surface of the shaft portion 2, and each flat surface portion 21 on the outer peripheral surface of the shaft portion 2 and the inner peripheral surface of the sleeve 3. It faces each other in the rolling contact state between each flat surface portion 31. The gap S between the flat surface portion 21 of the shaft portion 2 and the flat surface portion 31 of the sleeve 3 is formed to be slightly narrower than the roller diameter of the roller 4, and each roller 4 is connected to the shaft portion 2 and the sleeve 3. Is maintained in a state in which a preload is applied.

  The retainer 5 is provided with a position shift correction mechanism on the side wall 50 for correcting a position shift in the axial direction. That is, in the retainer 5, pocket portions 53 are formed in the six bent portions 52 of the side wall 50 so as to penetrate inside and outside. In addition, insertion holes 55 a and 55 b that penetrate in the axial direction and communicate with the pocket portion 53 are provided in the side wall portions 54 a and 54 b on both upper and lower sides of each pocket portion 53. A coil spring (elastic body) 6 is accommodated in each pocket portion 53, and a push pin 7 protruding in the axial direction from the side wall end face 56b of the retainer 5 is inserted and disposed in the insertion hole 55b on one side (FIG. 1). (See the cross section of (b)).

  Then, one end of the coil spring 6 is locked to the end edge portion of the push pin 7 facing the pocket portion 53. That is, the push pin 7 has a locking member 71 such as an E-ring attached to an end edge portion disposed in the pocket portion 53, and one end of the coil spring 6 is in contact with the locking member 71. The other end of the coil spring 6 is in contact with a plug member 72 that closes the insertion hole 55a on the other side. Therefore, the protrusion length of the push pin 7 from the side wall end surface 56b of the retainer 5 is set by the locking member 71 being brought into contact with the notch end surface 531b of the pocket portion 53 by the bias of the coil spring 6 (see FIG. (Refer to the cross section of 1 (b)). The protruding length of the push pin 7 may be set to a length in which the protruding tip 70 is in contact with the lid member 35a (35b) attached to the sleeve 3 in advance, or from the lid member 35a (35b). The length may be set at a predetermined interval. The push pins 7 protrude from the upper and lower side wall end faces 56a and 56b alternately in the circumferential direction at each of the six bent portions 52 of the retainer 5.

The bent portions 52 of the retainer 5 on which the push pins 7 and the coil springs 6 are arranged are formed thick with protrusions 52a and 52b on the inside and outside of the side wall 50 (in FIG. 1 (a)). (See the enlarged part of.) The inner convex portion 52 a and the outer convex portion 52 b are formed in a bowl shape over the entire axial length of the retainer 5. The height of each inner convex portion 52a is set so that the inner diameter connecting these top portions substantially coincides with the outer diameter connecting each corner portion of the outer peripheral surface of the shaft portion 2. Moreover, the height of each outer convex part 52b is set to the height which does not contact the sleeve 3 inner peripheral surface.
As described above, the bent portions 52 of the retainer 5 are thickened with the protrusions 52a and 52b. Therefore, the bent portions 52 of the retainer 5 are provided with pocket portions 53 and insertion holes 55a and 55b. However, the strength of the bent portion 52 is ensured, and the strength of the retainer 5 as a whole is not reduced.

With the above-described configuration, according to the linear motion bearing device 1 of the reference example , when the retainer 5 is moved in the axial direction along with the relative linear motion reciprocation between the shaft portion 2 and the sleeve 3, the push pin 7 The protruding tip 70 contacts the lid members 35a and 35b of the sleeve 3, and the coil spring 6 in the pocket portion 53 is compressed. When the external force on the retainer 5 is released and the movement of the retainer 5 in the axial direction is stopped, the retainer 5 is returned to the original position by the biasing force of the coil spring 6. Therefore, it is possible to correct the displacement so that the retainer 5 is automatically returned to the neutral position (reference position) of the sleeve 3.

  At this time, the retainer 5 is held concentrically with the shaft portion 2 by the inner convex portions 52a being in contact with the respective corner portions of the outer peripheral surface of the shaft portion 2, so that the radial vibration of the retainer 5 is restricted. ing. Accordingly, the push pin 7 that is in contact with the lid members 35a and 35b is maintained in a straight posture without being inclined, and thus is smoothly moved into the insertion holes 55a and 55b.

  As described above, the retainer 5 is not displaced with respect to the sleeve 3 and the shaft portion 2, so that the positional relationship between the roller 4 held by the retainer 5 and the shaft portion 2 and the sleeve 3 is not displaced. The relative linear motion reciprocation between the shaft portion 2 and the sleeve 3 can be performed stably and smoothly. In addition, since it is not necessary to form the recessed portion 111 (see FIG. 8) as in the prior art in the sleeve 3, it is possible to surely correct the displacement of the retainer 5 without reducing the strength of the sleeve 3. it can. As a result, it is possible to correct the displacement of the retainer 5 while maintaining the linear motion accuracy with high accuracy.

Moreover, co Irubane 6 is accommodated in the side wall 50 of the retainer 5, the press pin 7 is protruded so as to extend side wall end face 56a of the retainer 5 from 56b axially, the diameters of the sleeve 3 is larger Nor. Therefore, even if a displacement correction mechanism for the retainer 5 is provided, the overall size of the apparatus is not increased.

The insertion holes 55a and 55b may be cut out on the outer side (or the inner side) of the side wall so that the push pin 7 does not protrude.
Moreover, as shown in FIG. 5, you may form the pocket part 53x by the concave notch open | released outside. In this case, since the pocket portion 53x is recessed, the side wall 50x of the retainer 5 forming the pocket portion 53x is not penetrated inward and outward, so that the strength of the retainer 5 can be ensured.

(Embodiment 1 )
In the first embodiment, as shown in FIG. 2 , in the retainer 5, the core 8 through which the coil spring 6 is inserted is disposed in the pocket portion 53.
That is, the one shown in FIG. 2 is of a type in which the push pin 7 protrudes from the retainer 5, and a core portion 80 is formed to be continuous with the push pin 7 and through which the coil spring 6 in the pocket portion 53 is inserted. . Others are the same as the above reference example (see FIG. 1). The length of the core portion 80 is preferably such that even if all the protruding portions of the push pin 7 are immersed in the insertion hole 55b on one side, the core portion from the other insertion hole 55a to the outside of the retainer 5 is provided. 80 is a length that does not protrude. In this case, the coil spring 6 is compressed without being buckled by being guided by the core portion 80, and thus, the positional deviation correction of the retainer 5 can be reliably performed by the biasing force of the coil spring 6 in the axial direction.

(Embodiment 2 )
In the second embodiment, as shown in FIG. 3 , in the retainer 5, the push pin 7 or the coil spring 6 protrudes from both the upper and lower insertion holes 55 a and 55 b of the pocket portion 53.
That is, in the one shown in FIG. 3 , the push pin 7 longer than the axial length of the retainer 5 is disposed through the upper and lower insertion holes 55a and 55b so that both ends protrude from the side wall end surfaces 56a and 56b of the retainer 5, respectively. A locking member 71 such as an E-ring is attached to the center position of the push pin 7, and the two coil springs 6 a and 6 b are inserted into both sides straddling the locking member 71 and disposed in the pocket portion 53. In this case, position shift correction in the forward direction or the return direction of the retainer 5 can be performed at all locations where the push pins 7 are arranged. Others are the same as the above reference example (see FIG. 1).

(Embodiment 3 )
In the third embodiment, as shown in FIG. 4 , in the retainer 5, a pair of upper and lower flange portions 9 a and 9 b facing the axial direction is formed on the outer peripheral surface of the side wall 50, and the space between these flange portions 9 a and 9 b is a coil spring. 6 becomes a pocket portion 53 in which 6 is arranged. The upper and lower flange portions 9a and 9b are provided with insertion holes 55a and 55b penetrating in the axial direction. And although not shown in FIG. 4 , the coil spring 6 is arrange | positioned in the pocket part 53 between these collar parts 9a and 9b, and from this insertion hole 55a (55b) of one collar part 9a (9b), this coil spring 6 and projecting the push pin 7 for engaging (e.g., see FIG. 1), constituting the positional shift correcting mechanism of the above mentioned. Others are the same as those in the reference example and the first and second embodiments.

The flanges 9a and 9b are formed in the bent portion 52 of the retainer 5 of the hexagonal cylindrical body, and the recess 32 in the bent portion of the inner peripheral surface of the sleeve 3 having a hexagonal cross section (see FIG. 1A). ). And the external shape of the collar parts 9a and 9b is also circular arc shape according to the shape of the recess 32 of the sleeve 3 inner peripheral surface. Accordingly, the flanges 9a and 9b do not contact the inner peripheral surface of the sleeve 3.
Further, the positions of the upper and lower flange portions 9a and 9b may be formed along the opening of the retainer 5, or may be formed at an intermediate position (shown by a dotted line in FIG. 4 ). Further, it may be formed at both the opening and the intermediate position.

In the case of the third embodiment, the pocket portion 53 is formed without cutting out the side wall 50 of the retainer 5, so that the pocket portion 53 of the coil spring 6 can be formed while ensuring the strength of the retainer 5. Further, the pocket portion 53 can be easily formed without using a complicated mold when the retainer 5 is manufactured by injection molding or the like.

(Other)
The present invention is not limited to the above embodiment, and various design changes can be made.
For example, positional shift correcting mechanism by pins 7 press the coil spring 6 may also be provided in one location or any plurality of locations of the retainer 5. For example, the positional deviation correction mechanism may be provided at three equal intervals in the circumferential direction of the retainer 5, may be provided at two locations at the opposed positions, or may be provided at only one location.

Moreover, the structure which makes the side which makes the push pin 7 protrude may protrude only with respect to the side which raise | generates this position shift, when the retainer 5 raises position shift to one direction side. For example, when the linear motion bearing device 1 is arranged upright in the vertical direction and the retainer 5 is displaced downward due to gravity, the push pin 7 may be protruded only downward.

  Further, in the retainer 5, the pocket portion 53 and the insertion holes 55 a and 55 b communicating with the pocket portion 53 may be formed at appropriate positions on the side wall 50 as long as they are axial positions where no rolling elements such as the rollers 4 are arranged.

In addition, the sleeve 3 may not be provided with the cover members 35a and 35b, but may be provided with a large-diameter convex portion on the shaft portion 2 so that the protruding tip 70 of the push pin 7 contacts the large-diameter convex portion. .

In addition to the hexagon, the shape of the retainer 5 may be various polygonal shapes such as an octagon or a circle according to the shapes of the shaft portion 2 and the sleeve 3.
Moreover, the roller 4 which is a rolling element can use various types of rollers 4 such as a cylindrical shape, a drum shape, a drum shape, and a needle roller 4, and the rolling element is not limited to the roller 4 and uses a ball. But you can.
In addition, the linear motion bearing device 1 of the present invention can be applied to linear motion guides of various devices including a linear motion guide mechanism such as a die set device or a table transport device.

It is a figure which shows the structure of the linear motion bearing apparatus by a reference example , the figure (a) is a top view in the state which removed the cover member of the sleeve, and the figure (b) is one in which a part of sleeve and a retainer were notched. FIG. FIG. 3 is a schematic cross-sectional view showing the configuration of the retainer of the linear motion bearing device according to Embodiment 1 . 6 is a schematic cross-sectional view showing a configuration of a retainer of a linear motion bearing device according to Embodiment 2. FIG. 6 is a schematic cross-sectional view showing a configuration of a retainer of a linear motion bearing device according to Embodiment 3. FIG. It is a cross-sectional schematic diagram which shows the modification of a pocket part . It is a partial cross section figure which shows the structure of the conventional linear motion bearing apparatus .

DESCRIPTION OF SYMBOLS 1 Linear motion bearing apparatus 2 Shaft part 3 Sleeve 4 Roller 5 Retainer 6 Coil spring 7 Push pin 8 Core 9a, 9b Gutter part 35a, 35b Sleeve cover member 50 Side wall 52 Bending part 53 Pocket part 54a, 54b Side wall part 55a, 55b Insertion hole 56a, 56b Side wall end face 57 Through hole 70 Projection tip 80 Center part F Screw plug (clamp)
S gap

Claims (2)

A linear motion bearing device in which a cylindrical retainer is disposed in a gap between a shaft portion and a sleeve fitted to the shaft portion, and a rolling element is held by the retainer,
On the side wall of the retainer, an arrangement space for a coil spring serving as an elastic body is provided,
The arrangement space is opened to at least one of the side wall end faces in both openings of the retainer,
A push pin that is inserted through the entire area of the coil spring disposed in the arrangement space and engages one end of the coil spring is provided, and the push pin protrudes from the side wall end surface,
A linear motion bearing device in which a protruding tip of the push pin is disposed so as to be able to contact a lid member attached to an opening of the sleeve or a large-diameter convex portion provided on an outer peripheral surface of the shaft portion. The linear motion bearing device according to claim 1,
The retainer is formed in a polygonal cylinder, and a bent portion of a side wall of the retainer has a pocket portion serving as an arrangement space for arranging the coil spring, a convex portion formed on the wall, and an axis at the convex portion. An insertion hole penetrating in the direction and communicating with the pocket portion and through the push pin is provided,
A linear motion bearing device in which one end of the coil spring is locked to a locking member attached to the push pin, and the other end is locked to a peripheral edge of the insertion hole .