JPH04341608A - Rectilinear motion guidance device - Google Patents

Abstract

PURPOSE:To improve load-resistance of a device by holding a number of balls which support a sliding base onto an orbit base by means of a specified ball chain over a whole length of an infinite circulation passage, thereby preventing interference and collision between the balls, and reducing a span between the balls. CONSTITUTION:In a rectilinear motion guidance device, a sliding base 21 is assembled onto an orbit base 20 through number of balls 8. An infinite circulation passage 22 including a loaded area 23 and an unloaded area 24 of the balls 8 is formed on the sliding base 21. The balls 8 are held by means of an endless ball chain 1. The ball chain 1 is composed of chain unit elements 2 each having one fixing end 6 which is prepared by fixing each one of ends of a pair of holding arms 3, 4 through a connection member 5, and the other free end 7. The fixed end and free end 7 of the adjacent chain unit element 2 are sequentially connected to each other, and thereby the chain 1 is endlessly formed. The portions of the balls 8 exposed between the holding arms 3, 4 are in rotatably contact to the loaded ball passage 23.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion guide device that utilizes rolling balls.

0002

2. Description of the Related Art Conventional linear motion guide devices of this type include those shown in FIGS. 18(a) and 18(b), for example. That is, sliding guide is provided between the slide table 110 and the track base 111 via balls 112 as rolling elements, and an endless circulation path 113 in which the balls 112 circulate endlessly is constructed. That is, the endless circulation path 113 includes a loaded ball path 114, an unloaded ball path 115, and a direction change path 1.
16, so that the ball 112 is endlessly circulated from the load area to the no-load area.

0003

However, in the case of the conventional example described above, the ball is pushed by the ball 112 that sequentially moves from the load area to the no-load area, especially in the no-load ball path 114 and the direction change path 116. Because of this, the balls 112 interfere and compete with each other, causing problems such as collision noise between the balls 112 being generated and smooth movement of the balls 112 being obstructed.

Therefore, in order to prevent the balls 112 from competing with each other, the ball 112 is held by a ball chain and inserted into the endless circulation path 113 so that the ball 112 is
It is conceivable to arrange and circulate 12.

As a conventional ball chain, the one shown in FIGS. 19(a) and 19(b), for example, is known. That is, a large number of unit chain elements 101 holding individual balls 100 are rotatably connected to each other via connecting pins 102 in an endless manner.

The unit chain element 101 is a ball 100
A link plate 1 provided with a holding hole 103 that rotatably holds the
04, and both ends of this link plate 104 were connected via a connecting pin 102 to form an endless ball chain.

However, in such a ball chain, the balls 100 are held in the holding holes 103 of the link plates 104, and since the joint portion is located between the link plates 104, the pitch P1 between the balls 100, 100 becomes large. . Therefore, there was a problem in that the number of balls 100 to which a load is applied is reduced, resulting in a decrease in load performance.

[0008] Also, the pitch P between the balls 100 and 100
1 is large, and if an attempt was made to construct an infinite circulation path using such a ball chain, there was a problem in that the radius of the direction change path would become large and compact circulation movement would not be possible.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to hold a ball all around by a ball chain in a linear motion guide device having an endless circulation path. By doing so, it ensures the aligned circulation of the balls and completely eliminates problems caused by interference between the balls, and when holding the balls by a ball chain, the pitch between the balls is made as small as possible and the curvature of the refractive circulation path is minimized. By configuring the ball chain to have a smaller radius, it is possible to improve load-bearing performance and to make the device configuration thinner to improve stability.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention comprises a track base and a slide base that is slidably assembled to the track base via a large number of balls. In the linear motion guide device, the ball is held by an endless ball chain. The ball chain is slidably inserted into the endless circulation path, and one end of a pair of holding arms arranged in parallel at a predetermined interval is fixed via a connecting member to form a fixed end. A chain unit element is constructed with the other end being a free end, and the free end of the next stage chain unit element is successively pivotally connected to the fixed end of the chain unit element so as to be connected endlessly, and the holding arm of each chain unit element is The ball is slidably held in between.

[0011] Furthermore, it is preferable that the ball is slidably brought into contact with the connecting members of both the fixed end of the chain unit element holding the ball and the fixed end of the next stage chain unit element.

[0012] Furthermore, it is effective to make the contact surface of the connecting member with the ball a curved surface having a curvature approximately equal to the curvature of the ball surface.

[0013] Furthermore, it is preferable that the ball holding surface of the holding arm has a concave shape approximately equal to the curvature of the ball surface.

[0014] The chain unit element and the connecting member may be separated and independent, or may be integrally molded.

[0015] Still another invention is comprised of a track base and a slide base that is slidably assembled to the track base via a large number of balls, and the slide base has a load range of the balls. In a linear motion guide device provided with an endless circulation path that enables endless circulation between no-load areas, the ball is slidably inserted into the endless circulation path while being held by an endless ball chain, and the ball chain is inserted into the endless circulation path. is constituted by a chain unit element in which one end of a pair of holding arms arranged in parallel at a predetermined interval is fixed via a connecting member to serve as a fixed end, and the other end of the holding arm is a free end. The free end of the next stage chain unit element is successively pivotally connected to the fixed end of the unit element to form an endless connection, and a ball is slidably held between the holding arms of each of the chain unit elements. The portion exposed from between the holding arms is configured to be able to roll freely into contact with the rolling surface of the loaded ball rolling path in the load area, and
By creating an angle between the direction of chain bending and the direction in which the ball is held by the pair of holding arms, the direction of contact of the ball with the ball rolling surface in the load area and the direction of change of direction of the ball from the load area to the no-load area can be determined. It is characterized by an angle between it.

[0016] Here, the bending direction of the chain is the direction of the pivot axis in which each chain unit element is pivotally connected, and is the direction perpendicular to the circulation plane in which each chain unit element is bent and circulated. .

Further, the ball holding direction refers to a straight line direction passing through approximately the center of the holding arm to which each chain unit element is pivotally connected.

Furthermore, the contact angle line direction refers to the normal direction drawn to the contact portion with the ball rolling surface in the load area of the endless circulation path.

[0019]

[Operation] In the linear motion guide device having the above structure, since the balls are held by the ball chain over the entire length of the endless circulation path, the balls can be held at predetermined intervals without contact. In particular, it can be maintained at a predetermined interval within the unloaded ball passage and during direction changes between the loaded ball passage and the unloaded ball passage.
Interference between balls can be avoided.

[0020] By holding the balls between the holding arms of the chain unit elements, the span between the balls can be shortened compared to the conventional case where the balls are held in the holding holes of the link pieces. , the number of balls that carry the load increases, and the load-bearing performance improves.

[0021] Also, since the span between the balls becomes shorter,
The radius of curvature of the refractive circulation path of the ball chain can be reduced, and the sliding table forming the endless circulation path can be downsized.

Furthermore, if the pivot connection position between the chain unit elements is eccentric by a predetermined amount with respect to the center line connecting the centers of each ball, the ball chain can be refracted and circulated with this pivot connection position inside. This allows the radius of curvature to be further reduced.

Furthermore, the ball exposed surfaces exposed on opposite sides between the holding arms of the chain unit elements come into rolling contact with the ball rolling surfaces, so that the bending direction of the chain and
If the ball holding directions by the pair of holding arms are the same, the position of the ball passage in the no-load area of the ball circulation path must be located on an extension of the contact angle line of the ball. However, if an angle is created between the direction of refraction of the chain and the direction in which the ball is held by the pair of holding arms, an angle can be created between the direction of the contact angle line of the ball and the direction of the refraction circulation surface of the chain. The position of the ball passage in the no-load area can be set at an arbitrary position shifted from the extension line of the ball contact angle line.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the illustrated embodiments. 1 to 3 showing a linear motion guide device according to a first embodiment of the present invention, this linear motion guide device includes a track 20 and a track 20 that is slidably connected to the track 20 via a large number of balls 8. It is composed of a sliding table 21 to be assembled. Each ball 8 is incorporated into an endless circulation path 22 formed in the sliding table 21, and this endless circulation path 22 is shown in FIG.
As shown in FIG. 2, from a linear loaded ball passage 23 and an unloaded ball passage 24 extending parallel to each other, and arcuate direction change paths 25 and 26 connecting both ends of the loaded ball passage 23 and the unloaded ball passage 24. This endless circulation path 2
A ball chain 1 holding a ball 8 is incorporated into the ball chain 2. The linear motion guide device in the illustrated example has two
It is a four-direction equal load type with a total of four rows of balls arranged vertically and horizontally symmetrically, and the rated load on the top, bottom, left and right sides is equal.
Four endless circulation paths 22, . . . are provided, and one ball chain 1, . That is, jetties 27, 27 extending in the longitudinal direction are provided on the left and right side surfaces of the track base 20, and ball rolling surfaces 25 are provided at both upper and lower corners of the jetties, while ball rolling surfaces 25 are provided on the inner surface of the sliding base 21. A ball rolling surface 29 corresponding to the rolling surface 28 is provided, and the balls 8 held by the ball chain 1 are rotatably interposed between these ball rolling surfaces 28 and 29 to support the load. This ball rolling surface 28,2
Reference numeral 9 denotes a circular arc groove, in which the ball 8 contacts at two points and rolls. This ball 8 and each ball rolling surface 28, 29
In other words, the normal line of the contact part of the ball 8 with each ball rolling surface 28, 29 with respect to the horizontal line H passing through the center of the left and right jetties 27, 27 with the rolling surface horizontal (hereinafter referred to as contact angle). The angle formed with the angle line X) is approximately 45 degrees. Moreover, in this illustrated example, the contact structure is such that the left and right contact angle lines X, X, . The direction of each endless circulation path 22, . . . extends in the direction of the contact angle line X of the balls 8, and the no-load ball passages 24, . In addition, the ball direction changing paths 25 and 26 are
side covers 21b attached to both end surfaces of the sliding table main body 21a;
21b. As shown in FIGS. 4 to 7, the ball chain includes a large number of chain unit elements 2,...
It is composed of endlessly connected.

The chain unit element 2 is composed of a pair of holding arms 3 and 4 arranged in parallel at a predetermined interval, and a connecting pin 5 as a connecting member for fixing one end of the holding arms 3 and 4. Then, the side to be connected and fixed is a fixed end 6, and the other end is a free end 7, and the next stage chain unit elements 2 are successively pivotally connected to the fixed end 6 of this chain unit element 2, and connected in an endless manner. .

Holding arms 3 and 4 of each of the chain unit elements 2
While holding the ball 8 between them, the ball 8 is brought into contact with the connecting pins 5 of both the fixed end 6 of the chain unit element 2 holding this ball 8 and the fixed end 6 of the next stage chain unit element 2. There is.

The connecting pin 5 is composed of a shaft portion 9 interposed between the holding arms 3 and 4, and pivot shafts 10 and 11 projecting from both end surfaces of the shaft portion 9. and holding arm 3
The pivot shafts 10, 11 are rotatably inserted into the pin holes 12, 13 of , 4.

The holding arms 3, 4 are composed of curved pieces 31, 41 that are in contact with the surface of the ball 8, and joint pieces 32, 33; 42, 43 that extend to both ends of the curved pieces 31, 41. In this embodiment, the curved pieces 31, 41 and the joint pieces 32, 33; 42, 43 are formed to have the same width.

Then, the pin holes 12, 13 of the joint pieces 32, 42 on the fixed end side of one chain unit element 2 are inserted into the pin holes 12, 13 of the joint pieces 33, 43 on the free end 7 side of the next stage chain unit element 2. The pin holes 14 and 15 are overlapped and the pivot pins 10 and 11 are rotatably inserted, and the pivot shafts 10 and 1
The tip of 1 is crushed so that the width expands, and the crushed head 1
6 and 17 are designed to prevent it from coming off.

In this embodiment, the joint pieces 33, 43 on the free end side of the next stage are superimposed on the outside of the joint pieces 32, 42 on the fixed end side of the chain unit element 2.

The length of the shaft portion 9 of the connecting pin 5 is shorter than the diameter of the ball 8, and the positions of the heads 16, 17 of the pivot shafts 10, 11 are closer to the outermost diameter positions of the curved pieces 31, 41. It is also located inside. The holding surfaces on the inner periphery of the curved pieces 31 and 41 that are in contact with the ball 8 surface have a curved surface shape with a curvature that is almost the same as the curvature of the ball 8 surface.

On the other hand, the outer peripheral shape of the shaft portion 9 of the connecting pin 5 is as follows:
It has a drum shape with a diameter larger on both sides than the center, and its outer line in the direction of the central axis is formed into a curved surface that is approximately equal to the curvature of the surface of the ball 8. Thus, the ball 8 is surrounded by the curved pieces 31, 41 of the pair of holding arms 3, 4 and the connecting pins 5, 5, and is held in a four-point contact state. The contact portion of the ball 8 is held so that the frictional resistance is ideally zero so as not to impede the rolling motion of the ball 8, and also to prevent it from falling off.

Next, the movement of the ball 8 when the sliding table 21 moves will be explained.

When the slide table 21 moves relative to the track table 20, the slide table 21 of the load ball passage 23 of the endless circulation path 22 moves.
and the ball rolling surfaces 28 and 29 of the track 20, the ball 8
,... roll while supporting the load and move in the direction of movement of the sliding table 21.

Due to the movement of the ball 8 in this load range, each chain unit element 2, ... moves together with the ball 8 in the direction of movement of the sliding table 21, and the ball chain 1
Circulate endlessly within. By this movement of the ball chain 1, the balls 8 are sequentially supplied into the loaded ball passage 23 from the unloaded ball passage 24 from the rear end of the sliding table 21 in the moving direction through the ball direction changing passage 25.

In the entire stroke of the loaded ball passage 23, the direction change passages 25 and 26, and the unloaded ball passage 24 of the endless circulation path 22, each ball 8 is held by the chain unit element 2, and the balls 8 are held together by the chain unit element 2. move in alignment without interfering with each other.

The hole diameters of the direction change paths 25 and 26 and the unloaded ball path 24 are determined by the holding arms 4 and 2 of each chain unit element 2.
The diameter is larger than that of the ball 8 so that the ball 4 can move smoothly.

Each ball 8 has chain unit elements 2, 2
Since the connecting pins 5,... of the balls 8,... are brought into contact with each other, and the span P between the balls 8,... is made as small as possible, the loaded ball passage 2
A large number of balls 8, . . . can be interposed between the balls 3 and 3. Therefore, the load shared by each ball 8, . . . one by one can be reduced, and the withstand load can be increased.

Furthermore, since the span P between the balls 8, . It can be made smaller. As a result, the distance L between the loaded ball passage 23 and the unloaded ball passage 24 can be shortened, so that the size of the sliding table 21 can be further reduced.

[0040] In this way, it was possible to realize a linear motion guide device that has a large load-bearing capacity, is compact, and has a low center of gravity.

FIG. 8 shows an integrated structure of the chain unit elements of the apparatus of the first embodiment.

That is, in the chain unit element 2' shown in FIG. 8(a), a connecting pin 5' that connects the fixed ends 6' of the holding arms 3' and 4' is integrally molded with the holding arms 3' and 4'. Pivot pins 10', 11' are formed protruding from the joint pieces 32', 42' on the fixed end side. On the other hand, the joint pieces 33', 43 on the free end side of the holding arms 3', 4'
' are provided with pin holes 14', 15' into which pivot pins 10', 11' are rotatably inserted.

The chain unit element 2A' shown in FIG. 8(b) also has a pair of holding arms 3A', 4A' and a connecting pin 5A'.
However, in this configuration example, unlike the above configuration example, the pivot pin 10A'11A' that pivotally connects each chain unit element 2A' is connected to the chain unit element 2A'. The free ends of the pair of holding arms 3A', 4A' are formed to protrude inward so as to face each other, and the locking holes 14A are formed at the fixed ends of the next stage chain unit elements.
', 15A' are snap-engaged and pivotally connected in sequence.

FIG. 9 shows another example of the configuration of the ball chain, and the same components as those of the ball chain of the first embodiment are given the same reference numerals and will be explained as follows.
In this example, the chain unit element 202 pivot shaft 21
The position of 0,211 is eccentric by a predetermined amount e with respect to the center line connecting the centers of each ball 8. Then, the ball chain 201 is connected endlessly so that the pivot shafts 210 and 211 are on the inside, and the circulation radius R is as shown in FIG.
0, the balls 8, 8 can be made small enough to come into close contact with each other.

That is, the fixed end portions 206 of the holding arms 203, 204 of each chain unit element 202 are integrally molded via a stay portion 205 as a connecting member. The stay portion 205 is provided eccentrically outward with respect to the center line O connecting the ball centers, and the pivot shafts 210 and 211 fit into the inner edges of the fixed ends 206 of the holding arms 203 and 204. Pin holes 212 and 213 are bored.

The free ends 2 of the holding arms 203 and 204 of the next chain unit element 201 are inserted into the pin holes 212 and 213.
Pivot shafts 210 and 211 that protrude outward are rotatably inserted into 07.

The pivot shafts 210 and 211 are connected to each holding arm 2.
The pivot shafts 210, 211 are inserted into the pin holes 212, 213 from the inside of the ball chain 201, so that there is no risk of the pivot shafts 210, 211 coming off even if a tensile force is applied to the ball chain 201.

The ball 8 has each chain unit element 202,
... are connected and then assembled by press-fitting between the holding arms 203 and 204.

By using such a ball chain, the circulation radius of the ball chain can be made smaller, and a more compact linear motion guide device can be realized.

FIGS. 11 and 12 show a linear motion guide device according to a second embodiment of the present invention. In this embodiment as well, the same components as those in the first embodiment will be described with the same reference numerals.
As shown in FIG. 2, an angle is formed between the direction in which the ball 8 is held by the holding arms 303 and 304 that hold the ball 8 of the ball chain and the direction in which the ball chain 301 is bent.

That is, the refraction direction is in the direction of the pivot axis A of the connecting portion between each chain unit element 302, and extends at right angles to the refraction circulation surface C of the ball chain 301.
If a line connecting the centers of the holding arms 303 and 304 that hold the ball 8 is a holding axis B, this holding axis B is inclined at a predetermined angle with respect to the pivot axis A.

Looking at this point from another perspective, each holding arm 30
This means that the direction of the ball exposed portion exposed from between 3 and 304 is at an angle with respect to the direction perpendicular to the circulation plane C where the chain refracts and circulates. Here, the ball exposure direction refers to the ball center O and the pair of mutually opposing holding arms 303, 3.
Opposite ball exposed surfaces 8A exposed during 04
, 8B.

As shown in FIG. 11, the circulation surface C of the ball chain 301 is inclined in a direction approaching the horizontal line H with respect to the contact angle lines X and X of the balls 8, and the no-load ball passage 322, 323 is made narrower, the height of the sliding table 21 is made lower, and the sliding table 21 is constructed as a low center of gravity type.

That is, when the ball chain is assembled into the ball circulation path 22 of the linear motion guide device, the ball exposed surfaces exposed on opposite sides between the holding arms 304 and 305 of the ball chain unit element 302 are the ball rolling surface 28. ，
29 in a rotatable manner.

As in the first embodiment, the direction of the pivot axis A, which is the chain bending direction, and the pair of holding arms 303, 30
If the direction of the holding axis B, which is the ball holding direction according to 4, or the direction of the orthogonal line E, which is orthogonal to the direction of the exposed axis D, which is the direction of the ball exposed part, is the same, the endless circulation path 2 of the ball is the same.
The contact angle line X direction of the ball and the refractive circulation surface C of the chain in the load range of No.
The position of the no-load ball passage 24 in No. 2 is the contact angle line of the ball
It has no choice but to be established as an extension of the

However, as in this example, it is possible to make an angle in the direction perpendicular to the chain bending direction and the ball holding direction by the pair of holding arms 304, 305 or the direction of the ball exposed portion, so that the ball of the linear motion guide device Circulation route 22
The position of the no-load ball passage 24 can be set at any position shifted from the extension line of the ball contact angle line A narrower and more compact linear motion guide device can be provided.

Next, FIG. 13 shows another example of the structure of the ball chain applied to the linear motion guide device of this second embodiment.

Similar to the above configuration example, this ball chain also has a connecting pin and a pair of holding arms integrally molded from resin, but unlike the above configuration example, in this configuration example,
A pivot shaft 411 that pivotally connects each chain unit element,
A pair of holding arms 403, 404 of chain unit element 402
Free end portions 433 and 443 are formed to protrude inward so as to face each other.

Locking holes 412 into which the pivot shaft 411 is fitted are provided at both ends of the fixed end portions 432 and 442 of the chain unit element 402. The pivot shaft 411 is composed of a shaft main body 413 that projects with a constant thickness, and a triangular retaining head 414 that projects from the tip of the shaft main body 413 to a larger diameter than the shaft main body 413. On the other hand, locking hole 4
The shape of numeral 12 also follows the shape of the pivot shaft 411, and a triangular retaining portion 415 into which the retaining head 414 fits is formed at the rear end thereof.

[0060] A holding arm 403 that holds the ball 8
, 404 and the bending direction of the ball chain 401.

That is, the refraction direction is in the direction of the pivot axis A of the connecting portion between each chain unit element 402, and extends at right angles to the refraction circulation surface C of the ball chain 401.
If a line drawn in a direction connecting the centers of the holding arms 403 and 404 that hold the ball 8 is defined as a holding axis B, this holding axis B is inclined at a predetermined angle with respect to the pivot axis A.

Looking at this point from another perspective, each holding arm 40
This means that the direction of the ball exposed portion exposed from between 3 and 404 is angled with respect to the direction perpendicular to the circulation plane C where the chain refracts and circulates. Here, the ball exposure direction refers to the ball center O and the pair of mutually opposing holding arms 403, 4.
Opposite ball exposed surfaces 8A exposed during 04
, 8B. FIGS. 14 to 17 show linear motion guide devices according to still other embodiments. All of these embodiments use a ball chain 301 having the same configuration as the second embodiment,
An angle is set between the chain refraction direction and the ball holding direction, an angle is set between the chain refraction circulation surface and the ball contact angle line, and the position of the no-load ball passage is set at an arbitrary position. It is. Hereinafter, the same components as in the first and second embodiments will be described with the same reference numerals.

First, FIG. 14 shows a third embodiment of the present invention, and this embodiment device also has two rows of ball circulation paths on the left and right sides, upper and lower, but this example has different ball contact angles. The contact structure is such that the line X gradually closes inward and opens inward. In this example as well, the contact angle of the ball is approximately 45 degrees.

When the chain bending direction A and the ball holding direction B are the same, it is necessary to set the position of the unloaded ball passage 24 almost on the extension line of the contact angle line X. The unloaded ball passages 24, 24 cannot be placed overlapping each other at the same position, and the ball chain 30
The radius of curvature of 1 cannot be lower than a certain value, so
The minimum radius of curvature and contact angle geometrically determine the minimum possible span between the upper and lower two rows of load ball passages 23, 23, making it impossible to achieve compactness.

However, if an angle is set between the chain bending direction A and the ball holding direction B as shown in the illustrated example,
There is no need to locate the unloaded ball passage 24 on the extension line of the contact angle line, and the span between the two upper and lower rows of loaded ball passages can be maintained regardless of the size of the contact angle and the minimum radius of curvature of the direction change path of the ball chain. can be made smaller, and a more compact device can be realized.

FIG. 15 shows a fourth embodiment of the present invention. This fourth embodiment has particularly high support rigidity against loads from above, and although it has two rows of balls on the left and right, the contact angle is adjusted so that the upper load ball receives the load from above. is set at 90 degrees to the horizon. On the other hand, the load ball provided on the lower side is configured to contact the horizontal line at an angle of approximately 45 degrees. In this case as well, by providing an angle between the chain bending direction and the ball holding direction, the position of the no-load ball passage can be set at an arbitrary position shifted with respect to the extension line of the contact angle line.

A fifth embodiment of the present invention is shown in FIGS. 16 and 17.

In both FIGS. 16 and 17, the linear motion guide and feed is also of a separate type, and the track base 20A
and a sliding base 21A that is slidably assembled to the side surface of the track base 20A via two rows of upper and lower balls 8. The diagram shows a set of track base 20A and sliding base 21A.
Although only shown in the figure, two sets are usually prepared and arranged parallel to each other, and one sliding table 21A is equipped with a table (not shown).
One side of the table is fixed, and the other sliding table 21A is fixed to the other side of the table to guide the table.

The apparatus shown in FIG.
When A is on the inside, the contact structure is such that the contact angle line X of the ball 8 gradually widens toward the outside. By creating an angle between the chain bending direction A and the ball holding direction B, the no-load ball passage 24 provided in the sliding table 21A is placed inside the extension line of the contact angle line X. The vertical height of the sliding table 21A is made as small as possible.

On the other hand, the device shown in FIG. 17 has an inward-opening contact structure in which the contact angle line X of the ball 8 gradually widens inward, and other configurations and functions are shown in FIG. Since it is the same as the previous one, the explanation will be omitted.

[0071]

[Effects of the Invention] The present invention has the structure and operation described above, and since the balls are held by the ball chain over the entire length of the endless circulation path, the balls are held within the no-load ball passage and between the loaded ball passage and the no-load ball passage. Even when changing direction, the balls can be held at specified intervals, avoiding interference between the balls, completely preventing noise and competition due to ball collisions, and ensuring smooth alignment and circulation of the balls. It can be performed.

Furthermore, since the balls are held between the holding arms of the chain unit elements, the span between the balls can be shortened compared to the conventional case where the balls are held in the holding holes of the link pieces, and the load can be reduced. The number of loaded balls increases, and the load-bearing performance improves.

Furthermore, since the span between the balls is shortened, the radius of curvature of the refractive circulation path of the ball chain can be reduced, and the device configuration can be made compact.

Furthermore, if the pivot connection position between the chain unit elements is eccentric by a predetermined amount with respect to the center line connecting the centers of each ball, the ball chain can be refracted and circulated with this pivot connection position inside. By doing so, the radius of curvature can be further reduced.

Furthermore, when the bending direction of the chain and the direction in which the ball is held by the pair of holding arms are the same, the position of the ball passage in the no-load area of the ball circulation path must be provided on the extension line of the contact angle line of the ball. You won't get any more. However, if an angle is created between the direction of refraction of the chain and the direction in which the ball is held by the pair of holding arms, an angle can be created between the direction of the contact angle line of the ball and the direction of the refraction circulation surface of the chain. The position of the ball passage in the no-load area can be set at an arbitrary position shifted from the extension line of the ball contact angle line.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a linear motion guide device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of one endless circuit of FIG. 1;

FIG. 3 is a schematic perspective view of the linear motion guide device of FIG. 1;

4 is a plan cross-sectional view of a portion of the ball chain of the device of FIG. 1; FIG.

FIG. 5 is a plan view of FIG. 4;

6 is a front view showing the state of the circulation radius of the balls of the ball chain in FIG. 4; FIG.

7(a) is a perspective view of the chain unit element of the ball chain in FIG. 1, FIG. 7(b) is an exploded perspective view of FIG. 7(a), and FIG. 7(c) is a perspective view of the connected state. It is.

8(a) is a perspective view of an integrally molded type of chain unit element in FIG. 4, and FIG. 8(b) is a perspective view of another embodiment of the integrally molded type.

9 shows another example of the configuration of the ball chain shown in FIG. 4, in which FIG. 9(a) is a partial perspective view, and FIG. 9(b) is a perspective view of a chain unit element.

FIG. 10 is a front view showing the state of the circulation radius of the ball chain in FIG. 9;

FIG. 11 is a front sectional view of a linear motion guide device according to a second embodiment of the present invention.

12(a) is a partial perspective view of the ball chain of the apparatus shown in FIG. 11, and FIG. 12(b) is a front view of the chain unit element.

FIG. 13 shows chain unit elements of a ball chain of another configuration incorporated in the device of FIG. 11;
Figure (a) is a perspective view, figure (b) is a front view, figure (c)
is a left side view, (d) is a right side view, (e) is a cross-sectional view taken along line A--A in (b), and (f) is a plan view.

FIG. 14 is a front sectional view of a linear motion guide device according to a third embodiment of the present invention.

FIG. 15 is a front sectional view of a linear motion guide device according to a fourth embodiment of the present invention.

FIG. 16 is a front sectional view of a linear motion guide device according to a fifth embodiment of the present invention.

FIG. 17 is a front sectional view of a linear motion guide device of another embodiment of the device of FIG. 16;

FIG. 18 shows a conventional linear motion guide device, in which FIG. 18(a) is a front sectional view and FIG. 18(b) is a side sectional view.

FIG. 19 shows a conventional ball chain, with FIG. 19(a) being a partial front view and FIG. 19(b) being a plan sectional view.

[Explanation of symbols]

1,201,301 Ball chain 2,202,3
02 Chain unit element 3,203,303 Holding arm 4,204,304 Holding arm 5 Connecting pin 6,206 Fixed end 7,207 Free end 8 Balls 10, 11 Pivot shaft 20 Track base 21 Sliding base 22 Endless circulation path 23 Loaded ball passage 24 Unloaded ball passage 25, 26 Ball direction change path H Horizontal line Surface D Exposure axis E Orthogonal line O Ball center

Claims (8)

[Claims] Claim 1: Consisting of a track base and a slide base that is slidably assembled to the track base via a number of balls, the slide base has a cross section between a load range of the balls and a non-load range of the balls. In a linear motion guide device provided with an endless circulation path that enables endless circulation of the ball, the ball is slidably inserted into the endless circulation path while being held by an endless ball chain, and the ball chain is Consisting of a chain unit element in which one end of a pair of holding arms arranged in parallel at a predetermined interval is fixed via a connecting member to serve as a fixed end, and the other end of the holding arm is a free end, the chain unit element The free ends of the next stage chain unit elements are successively pivotally connected to the fixed end of the chain unit element to form an endless connection, and a ball is slidably held between the holding arms of each of the chain unit elements, and the ball is held in the holding position. A linear motion guide device characterized in that a portion exposed from between the arms is configured to be able to roll freely into contact with a rolling surface of a loaded ball rolling path in a loaded region. 2. The linear motion according to claim 1, wherein the ball is slidably brought into contact with the connecting members at both the fixed end of the chain unit element holding the ball and the fixed end of the next stage chain unit element. Guidance device. 3. The linear motion guide device according to claim 1, wherein the contact surface of the connecting member with the ball has a curved shape substantially equal to the curvature of the ball surface. 4. The linear motion guide device according to claim 1, wherein the ball holding surface of the holding arm has a concave shape substantially equal to the curvature of the ball surface. 5. The linear motion guide device according to claim 1, wherein the chain unit element and the connecting member are separated and independent. 6. The linear motion guide device according to claim 1, wherein the chain unit element and the connecting member are integrally molded. 7. The linear motion guide according to claim 1, wherein the pivot connection position between the chain unit elements is eccentric by a predetermined amount with respect to a center line connecting the centers of each ball. Device. 8. Consisting of a track base and a sliding base that is slidably assembled to the track base via a number of balls,
In the linear motion guide device, the sliding table is provided with an endless circulation path that allows the balls to circulate endlessly between a loaded area and a non-loaded area, with the balls being held by an endless ball chain. Each of the ball chains is slidably inserted into the endless circulation path, and the ball chain fixes one end of a pair of holding arms arranged in parallel at a predetermined interval via a connecting member to form a fixed end, and the other end of the holding arm. The fixed end of the chain unit element is successively pivotally connected to the free end of the next chain unit element to form an endless connection between the holding arms of each chain unit element. The ball is slidably held in the holding arm, and the portion of the ball exposed between the holding arms is configured to be able to roll freely into contact with the rolling surface of the loaded ball rolling path in the load area, and the chain bending By creating an angle between the direction and the direction in which the ball is held by the pair of holding arms, an angle can be created between the contact angle line direction of the ball with the ball rolling surface in the load range and the refractive circulation surface of the chain. A linear motion guide device featuring: