JP6047694B2 - Linear motion bearing device - Google Patents

Description

  The present invention relates to a linear bearing device including a retainer that is interposed between a shaft portion and a sleeve inserted through the shaft portion and rotatably holds a number of rolling elements.

  As a linear motion bearing device, a polygonal cylindrical retainer is loosely fitted in a gap between a polygonal shaft portion of the outer peripheral surface and a polygonal sleeve whose inner peripheral surface is inserted along the outer peripheral surface of the shaft portion. Some retainers hold a number of roller-like rolling elements (see Patent Document 1). In this linear motion bearing device, the rolling element is interposed between the outer peripheral surface of the shaft portion and the inner peripheral surface of the sleeve in a preloaded state and brought into rolling contact, so that the shaft portion and the sleeve are repeatedly and linearly reciprocated lightly and lightly. Can move.

JP 2008-232175 A

  In the linear motion bearing device, since the rolling element is interposed between the shaft portion and the sleeve, a preload is applied to the rolling element so that no gap is generated between the shaft portion and the sleeve and the rolling element. In this case, since the rolling element is elastically deformed by pressing the shaft part and the sleeve against the rolling element, a large rush shock occurs when the rolling element enters between the shaft part and the sleeve. Therefore, adjustment may be difficult when the linear motion bearing device is used for a precision mold.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a linear motion bearing device that reduces a rush shock that occurs when a rolling element held by a retainer enters the sleeve, and enables good sliding. And

In the linear motion bearing device of the present invention, an outer peripheral surface is formed into a polygonal shape by a plurality of flat portions, the shaft portion is inserted, and an inner peripheral surface is formed by a plurality of flat portions in accordance with the outer peripheral surface of the shaft portion. A sleeve formed in a polygonal shape, a retainer that is loosely fitted in a gap between the shaft portion and the sleeve, and is formed into a polygonal cylindrical body by a plurality of plane portions according to the shape of the gap, and each plane of the retainer A linear motion bearing used for precision molds, comprising a roller-like rolling element that is rotatably held in contact with the shaft portion and the sleeve in a large number of holding holes formed through the shaft in the axial direction of the shaft portion A device,
The holding hole is formed such that the center position of each holding hole adjacent in the retainer circumferential direction is shifted in the axial direction of the shaft by a distance of 1/10 to 1/2 of the radius of the rolling element. To do.

With the above configuration, the rolling elements adjacent to each other in the circumferential direction of the retainer are arranged in the retainer holding holes with the axial center position slightly shifted in the axial direction of the shaft, so that each rolling element enters the sleeve together with the retainer. When doing so, the rolling elements arranged in the circumferential direction enter the sleeve with a slight time difference.
As a result, the rolling elements arranged in the circumferential direction of the retainer, for example, after the half of the rolling elements start to enter the sleeve, the remaining half of the rolling elements start to enter the sleeve immediately after almost no time. The magnitude of the inrush shock is smaller than when all the rolling elements arranged in the circumferential direction enter the sleeve at the same time. Therefore, adjustment when the linear motion bearing device is used for a precise mold is facilitated.

It is preferable that the retainer cuts a central portion in the longitudinal direction of the partition portion formed between the holding holes arranged in the axial direction in each plane portion to form a communication pocket portion that connects the holding holes.
By forming the communication pocket portion in the partition portion of the retainer in this way, the communication pocket portion serves as an oil reservoir for lubricating the rolling element, and the sliding member can slide well with respect to the shaft portion and the sleeve. it can.

  In particular, when every other communication pocket portion is formed with respect to the partition portions arranged in the axial direction of the shaft portion, it is possible to satisfactorily lubricate the rolling elements and suppress a decrease in the strength of the retainer. be able to.

  Furthermore, when the oil-containing resin is filled in the communication pocket portion, oil can be reliably lubricated to the rolling elements.

Further, in the linear motion bearing device of the present invention, the shaft portion is formed with the flat portion and the curved portion alternately on the outer peripheral surface, and the sleeve has the flat portion and the curved portion on the inner peripheral surface in accordance with the outer peripheral surface of the shaft portion. Alternately formed, the retainer is formed alternately with the flat surface portion and the curved surface portion in accordance with the shape of the gap between the shaft portion and the sleeve, and inward of the axial direction axial end portions of the outer peripheral surface of each curved surface portion, It is preferable that a rib extending in the circumferential direction is formed.
Thus, the strength of the retainer can be improved by forming the rib extending in the circumferential direction on the curved surface portion of the retainer.

Furthermore, it is preferable that the rib formed on each curved surface portion of the retainer is formed continuously with any partition portion in the circumferential direction. In this case, it is preferable to form with respect to the partition part in which the communication pocket part is not formed.
By comprising in this way, since a rib is continuously formed in a partition part, the intensity | strength of a retainer can be improved further more favorably.

Further, in the linear motion bearing device of the present invention, the shaft portion is formed with the flat portion and the curved portion alternately on the outer peripheral surface, and the sleeve has the flat portion and the curved portion on the inner peripheral surface in accordance with the outer peripheral surface of the shaft portion. Alternatingly formed, the retainer is formed alternately with the flat surface and the curved surface according to the shape of the gap between the shaft and the sleeve, and extends in the axial direction at both axial ends of the outer periphery of each curved surface. Ribs can also be formed.
In this way, by forming ribs at both axial ends of the retainer in the axial direction, the strength of the retainer can be improved, and the thickness of the retainers in the axial direction at both ends in the axial direction is increased. It can be used as a spring receiver for a spring that urges the end of the retainer to hold it at a fixed position between the shaft and the sleeve.

  According to the linear motion bearing device of the present invention, it is possible to reduce a rush shock that occurs when a rolling element rotatably held by the retainer enters the sleeve, and there is no decrease in the strength of the retainer. Sliding can be performed smoothly.

It is a side view which shows the external appearance of the linear motion bearing apparatus by this Embodiment 1. It is sectional drawing of the linear motion bearing apparatus by this Embodiment 1. It is a perspective view of the retainer used for the linear motion bearing device by this Embodiment 1. It is a front view of the retainer used for the linear motion bearing device by this Embodiment 1. It is a perspective view of the retainer used for the linear motion bearing device by this Embodiment 2. It is a perspective view of the retainer used for the linear motion bearing device by this Embodiment 3.

[Embodiment 1]
Embodiment 1 of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, in the linear motion bearing device 1 according to the first embodiment, a cylindrical sleeve 3 having an insertion hole 31 having a polygonal cross section is inserted into a shaft portion 2 having a polygonal outer peripheral surface. In the gap between the shaft portion 2 and the sleeve 3, a retainer 5 </ b> A made of a polygonal cylinder holding a number of rollers 4 (rolling elements) is loosely fitted.

  The shaft portion 2 has a long hexagonal sleeve sliding portion 23 whose outer peripheral surface alternately has flat portions 21 and curved surface portions 22, and an end portion 24 formed on one end side of the sleeve sliding portion 23. Prepare. In the sleeve 3, the hexagonal sleeve sliding portion 23 of the shaft portion 2 is inserted, and the inner peripheral surface of the insertion hole 31 alternates between the flat surface portion 32 and the curved surface portion 33 according to the outer peripheral surface of the sleeve sliding portion 23. It has a hexagonal shape.

  The retainer 5A is loosely fitted in the gap between the shaft portion 2 and the sleeve 3, and is formed of a hexagonal cylinder having alternating flat portions 51 and curved portions 52 in accordance with the shape of the gap. In each planar portion 51 of the retainer 5A, a large number of holding holes 53 are formed side by side so as to penetrate the shaft portion in the axial direction and hold the roller 4 rotatably. In these holding holes 53, the roller 4 is rotatably held so as to contact the outer peripheral surface of the shaft portion 2 and the inner peripheral surface of the sleeve 3. Accordingly, a large number of rollers 4 rotatably held in the holding holes 53 of the retainer 5A are arranged corresponding to the positions of the flat portions 21 of the shaft portion 2, and the flat portions 21 of the shaft portion 2 and the flat surfaces of the sleeve 3 are arranged. It faces the rolling contact state between the part 32. The gap between the flat surface portion 21 of the shaft portion 2 and the flat surface portion 32 of the sleeve 3 is formed to be slightly narrower than the roller diameter of the roller 4, and each roller 4 has a gap between the shaft portion 2 and the sleeve 3. Inside, it is held in a preloaded state.

  As shown in FIG. 4, the plurality of holding holes 53 formed in each flat portion 51 of the retainer 5 </ b> A are arranged so that the center position of the holding holes 53 adjacent to the circumferential direction of the retainer 5 </ b> A is the radius of the roller 4 in the axial direction of the shaft portion. Are formed at a distance (a) equal to or less than ½ of the distance. The distance (a) is preferably 1/6 to 1/10 of the radius. For example, the distance (a) can be about 1/8 of the radius. As described above, the rollers 4 arranged in the circumferential direction of the retainer 5 </ b> A are separated from each other after the half roller 4 starts to enter the sleeve 3 from the outside of the sleeve 3 during the relative movement of the shaft portion 2 and the sleeve 3. a) Since the remaining half of the roller 4 starts to enter the sleeve 3 with a delay of a considerable amount of time, the magnitude of the rush shock into the sleeve 3 is that all the rollers 4 (rolling elements) arranged in the circumferential direction At the same time, it becomes smaller than the case where entry into the sleeve 3 starts.

  Further, since the axial center positions of the rollers 4 adjacent to each other in the circumferential direction are only shifted in the axial direction of the shaft portion by a slight distance (a), the entry of the rollers 4 at the same stage in the circumferential direction into the sleeve 3 starts. Although there is a time lag corresponding to the distance (a), it occurs almost simultaneously. Therefore, for example, compared to a case where the rollers 4 in adjacent rows are shifted in the axial direction by the roller radius, the interval at which the rush shock occurs is larger become longer. For example, the time interval from the occurrence of a rush shock when the first-stage roller 4 enters to the time when the second-stage roller 4 enters the rush shock becomes longer. Therefore, the rush shock is reduced and the adjustment when the linear motion bearing device 1 is used for a precision mold is facilitated, the length of the retainer 5A is not unnecessarily increased, and the axial direction of the shaft portion of the retainer 5A is reduced. Since there is no stepped notch portion due to the holding hole 53 at the end, the strength does not decrease.

  Further, in the retainer 5 </ b> A, a partition portion 54 is formed between the holding holes 53 arranged in the axial direction of each shaft portion 51. And every other partition part 54 arranged in the axial direction of the shaft part is formed with a communication pocket part 55 that cuts the center part in the longitudinal direction of the partition part 54 and communicates the upper and lower holding holes 53 with each other.

Since the inside of the communication pocket portion 55 serves as an oil reservoir for holding a lubricant such as lubricating oil, the lubricating oil held in the communication pocket portion 55 is supplied to the roller 4, and the friction resistance in the roller 4 is reduced. Can be maintained for a long time. As a result, the lubricating oil accumulated in the communication pocket portion 55 improves the sliding of the roller 4 with respect to the shaft portion 2 and the sleeve 3. In the first embodiment, since every other communication pocket portion 55 is formed with respect to the partition portions 54 arranged in the axial direction of the shaft portion, the lubricating oil can be satisfactorily supplied to the roller 4, and the communication A decrease in strength of the retainer 5A due to the formation of the pocket portion 55 can be suppressed.
In addition, you may make it fill these communicating pocket parts 55 with an oil-containing resin. In this case, it is possible to reliably supply the lubricating oil to the roller 4.

  As shown in FIGS. 3 and 4, intermediate ribs 56 extending in the circumferential direction are formed on the outer peripheral surface of each curved surface portion 52 of the retainer 5 </ b> A inward from both axial end portions in the axial direction. These intermediate ribs 56 are formed so as to be continuous in the circumferential direction with any of the partition portions 54 where the communication pocket portions 55 are not formed. Thus, by forming the intermediate rib 56 on each curved surface portion 52, the strength of the retainer 5A can be improved. In particular, since the intermediate rib 56 is formed continuously to the partition portion 54 where the communication pocket portion 55 is not formed, the strength of the retainer 5A can be improved satisfactorily.

  Further, end ribs 57 are formed at both ends in the axial direction of the outer peripheral surface of each curved surface portion 52 of the retainer 5 </ b> A so as to continue to the adjacent curved surface portion 52 via the flat surface portion 51. By forming the end ribs 57 at both axial ends of the retainer 5A in the axial direction, the strength of the retainer 5A can be increased, and the thickness of the cylindrical portion of the retainer 5A is increased at the portion where the end ribs 57 are formed. Since the thickness increases, the retainer 5A is urged into the sleeve 3 by interposing a coil spring between the flange portion of the end portion 24 formed on the end portion 24 of the shaft portion 2 and the end surface of the retainer 5A. Misalignment can be prevented, and this end rib 57 can be used as a spring support.

  According to the linear bearing device 1 as described above, the roller 4 held by the retainer 5A enters the sleeve 3 when the shaft portion 2 and the sleeve 3 move relative to each other without the sleeve 3 becoming unnecessarily long. Since the inrush shock at the time can be reduced and the sliding resistance can be reduced, a light and light linear motion can be stably obtained over a long period of time.

[Embodiment 2]
In the first embodiment, the intermediate ribs 56 are formed in two places on the upper and lower sides. However, the intermediate ribs 56 may be formed on either the upper or lower side like the retainer 5B of the second embodiment shown in FIG.

[Embodiment 3]
Further, unlike the retainer 5C of the third embodiment shown in FIG. 6, the intermediate ribs may not be formed, only the end ribs 57 at both ends in the axial direction of the shaft may be formed, and the communication pocket portion may not be formed. In the third embodiment, a communication pocket portion can also be formed.

[Other]
Further, although the retainer is not shown, it is also possible to prevent the intermediate rib and the end rib from being formed.
Moreover, it is possible not to form the communication pocket portion in the partition portion of the retainer, or it is possible to form the communication pocket portion in all the partition portions.
In addition to the hexagon, the shape of the retainer may be various polygonal shapes such as a square and an octagon according to the shapes of the shaft portion and the sleeve.

[Application example]
The linear motion bearing device according to each embodiment described above can be applied to, for example, a pair of left and right linear motion guides in a die set of a mold. In addition, the linear motion bearing device of the present invention can be applied to various linear motion guides such as table conveyance in addition to the die set.

  The linear motion bearing device of the present invention is not limited to the above embodiment, and the above embodiment is merely an example, and does not limit the scope of the claims. That is, the technology described in the claims is not limited to the embodiment described with reference to the above description and drawings, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Linear motion bearing apparatus 2 Shaft part 3 Sleeve 4 Roller 5A, 5B, 5C Retainer 21 Flat part 22 Curved part 23 Sleeve sliding part 24 End part 31 Insertion hole 32 Flat part 33 Curved part 51 Flat part 52 Curved part 53 Holding hole 54 Partition 55 Communication Pocket 56 Intermediate Rib 57 End Rib

Claims (7)

A shaft portion whose outer peripheral surface is formed in a polygonal shape by a plurality of flat portions, a sleeve through which the shaft portion is inserted, and an inner peripheral surface is formed in a polygonal shape by a plurality of flat portions in accordance with the outer peripheral surface of the shaft portion, A retainer that is loosely fitted in the gap between the shaft portion and the sleeve, and that is formed into a polygonal cylindrical body by a plurality of flat portions according to the shape of the gap, and penetrates each flat portion of the retainer in the axial direction of the shaft portion A linear motion bearing device used for precision molds, comprising a plurality of formed holding holes and a roller-like rolling element that is rotatably held in contact with the shaft portion and the sleeve,
The holding hole is a linear motion bearing device in which the center positions of the holding holes adjacent to each other in the circumferential direction of the retainer are shifted in the axial direction of the shaft by a distance of 1/10 or more and 1/2 or less of the radius of the rolling element. . The linear motion bearing device according to claim 1,
The retainer is a linear motion bearing device in which a communication pocket portion is formed by cutting a central portion in a longitudinal direction of a partition portion formed between holding holes arranged in the axial direction of the shaft portion in each plane portion to communicate the holding holes with each other. . The linear motion bearing device according to claim 2,
The communication pocket portion is a linear motion bearing device that is formed every other partition portion arranged in the axial direction of the shaft portion. In the linear motion bearing device according to claim 2 or 3,
A linear motion bearing device in which the communicating pocket portion is filled with an oil-containing resin. The linear motion bearing device according to any one of claims 1 to 4,
The shaft portion is formed with alternately flat and curved portions on the outer peripheral surface,
According to the outer peripheral surface of the shaft portion, the sleeve is alternately formed with flat portions and curved surface portions on the inner peripheral surface,
The retainer has ribs extending in the circumferential direction inward from the axial end portions of the axial portion on the outer peripheral surface of each curved surface portion, in which the flat surface portion and the curved surface portion are alternately formed according to the shape of the gap between the shaft portion and the sleeve. A linear motion bearing device in which is formed. In the linear motion bearing device according to claim 5,
The linear motion bearing device in which the rib formed on the retainer is continuously formed in the circumferential direction with any partition portion. In the linear motion bearing device according to any one of claims 1 to 6,
The shaft portion is formed with alternately flat and curved portions on the outer peripheral surface,
According to the outer peripheral surface of the shaft portion, the sleeve is alternately formed with flat portions and curved surface portions on the inner peripheral surface,
In the retainer, flat portions and curved surface portions are alternately formed in accordance with the shape of the gap between the shaft portion and the sleeve, and ribs extending in the circumferential direction are formed at both axial end portions of the outer peripheral surface of each curved surface portion. Linear motion bearing device.

Images