JPH10318209A - Rodless cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rodless cylinder being of structure wherein play hardly occurs to a bearing structure having a number of rolling bodies contained in a rolling state in an infinite circulation passage, resulting in continuence of reciprocation of a driven part with high precision without play, and an installation space is comparatively small. SOLUTION: Grooves 31 for guiding inside load ball are formed in the two sides of a driven part 5 having a through-part 25 extending through a cylinder tube 3. Guide grooves 34 for an outside load ball are formed in the two inner sides of a groove recessed part 33 formed in a guide rail 1. A number of rolling bodies 37 are located in a rolling state between the guide groove 31 and 34 positioned facing each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rodless cylinder for transferring, supplying or removing parts or products in a process such as processing or assembly.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS.
A pair of grooves 52 are provided on the side surface of the cylinder tube 51, and ball ways 54 are provided on the inner side surfaces of the substantially U-shaped guide arms 53 disposed so as to straddle the cylinder tube 51 so as to face the grooves 52, respectively. Infinite circulation path 5 consisting of this groove 52 and ballway 54
5 is a rodless cylinder in which a number of ball-shaped rolling elements 56 are rotatably accommodated.

However, in this rodless cylinder, an internal piston (not shown) and a guide arm 5 are provided on the top plate of the cylinder tube 51 over its entire length.
3 is provided with a slit (not shown) for passing a connecting portion (not shown) for connecting the third member 3. Therefore, when an external force acts in a direction in which the width of the slit increases or decreases, the cylinder tube 51 is relatively easily deformed. The guide arm 53 having a substantially U-shape has a relatively short length in the reciprocating direction as illustrated. Therefore, when an external force acts in a direction in which the distance between the two ends of the U-shape increases or decreases, the guide arm 53 is also relatively easily deformed.

Accordingly, in the rodless cylinder, since the cylinder tube 51 and the guide arm 53 are relatively easily deformed when subjected to a force, play is generated between the groove 52 and the rolling element 56. In addition, there is a problem that the life of a piston or a piston seal (not shown) sliding inside the cylinder tube 51 is adversely affected.

[0005] From the viewpoint of abrasion resistance, the cylinder tube 51 is subjected to a heat treatment so that the surface of the groove 52 has a required hardness, and then is finished to a precise shape by grinding.
However, during grinding, the cylinder tube 51 is deformed due to the pressing of the grindstone. Therefore, in order to obtain the required accuracy, a single grinding allowance must be made very small. In addition, unlike guide rails of ordinary linear bearings, the cylinder tube 51 is easily deformed by heat treatment and has a shape that is difficult to correct, and inevitably increases the grinding allowance of the groove 52 and increases the processing cost. Further, it is extremely difficult to correct distortion generated in a cylinder chamber (not shown).

Further, Japanese Patent Application Laid-Open No.
In the rodless cylinder disclosed in Japanese Patent Publication No. 269515, although the strength of the bearing structure (linear motion bearing) is sufficient, the cylinder tube and the guide rail are arranged in parallel in the width direction when viewed in plan. However, there is a disadvantage that the installation space in the width direction is relatively large.

[0007]

SUMMARY OF THE INVENTION In view of the above, the present invention has been made in view of the above points, and it is difficult for the bearing structure in which a large number of ball-shaped rolling elements are rotatably accommodated in an infinite circulation path to generate backlash. It is an object of the present invention to provide a rodless cylinder having a structure in which a table continues to reciprocate with high precision without play and has a relatively small installation space.

In addition to the above, a shock absorber or a stopper for adjusting the end position of the driven table so as to be adjustable or a sensor or a switch for detecting that the driven table has moved to a predetermined position and sending a signal to the outside is provided. Even so, an object of the present invention is to provide a rodless cylinder having a relatively small installation space.

[0009]

In order to achieve the above object, a rodless cylinder according to a first aspect of the present invention reciprocates in a cylinder tube made of a non-magnetic material and in the cylinder tube by supplying fluid pressure. A piston having a required number of permanent magnets, and a penetrating portion that penetrates the cylinder tube, reciprocates according to the piston by the magnetic force of the permanent magnet, and has guide grooves for inner load balls on both side surfaces. A driven portion, and a groove-shaped concave portion along the reciprocating direction of the driven portion, and a guide groove for an outer load ball provided on both inner side surfaces of the concave portion so as to face the guide groove for the inner load ball. A number of ball-shaped rolling members rotatably accommodated in an infinite circulation path including a guide rail and a straight path including the inner load ball guide groove and the outer load ball guide groove. And to have a body.

A rodless cylinder according to a second aspect of the present invention includes a cylinder tube made of a non-magnetic material, a piston reciprocating in the cylinder tube by supplying a fluid pressure, and having a required number of permanent magnets. A penetrating portion that penetrates the cylinder tube, reciprocates according to the piston by the magnetic force of the permanent magnet, has a guide groove for an inner load ball on each side surface, and a pair of guide holes for a no-load ball therein. A driven table provided in parallel with the inner load ball guide groove, and a circulation path fixed to both end surfaces of the driven table and communicating the inner load ball guide groove and the no-load ball guide hole therein are provided. A pair of end lids, a groove-shaped recess along the reciprocating direction of the driven table, and outer load ball guides on both inner side surfaces of the recess. And a guide rail provided so as to face the inner load ball guide groove, and an infinite circulation path including the inner load ball guide groove, the outer load ball guide groove, a circulation path, and a no-load ball guide hole. And a number of ball-shaped rolling elements movably housed therein.

According to a third aspect of the present invention, there is provided the rodless cylinder according to the second aspect, wherein an end cover is fixed to the driven table by a bolt, and a head of the bolt is moved by the moving of the driven table. A shock absorber that regulates the end position in an adjustable manner or a stopper receiver that comes into contact with the stopper is adopted.

According to a fourth aspect of the present invention, there is provided the rodless cylinder according to the second aspect, wherein an end cover is fixed to the driven table by a bolt, and the head of the bolt is fixed to the driven table by a predetermined distance. The sensor or switch that detects that it has moved to the position and sends a signal to the outside is to be detected.

[0013] In the rodless cylinder according to the first aspect of the present invention having the above structure, guide grooves for inner load balls are provided on both side surfaces of the driven portion, respectively, and both of the groove-shaped concave portions provided on the guide rail are provided. A guide groove for an outer load ball is provided on each of the inner side surfaces, and a number of ball-shaped rolling elements are respectively rotatably interposed between the two pairs of guide grooves facing each other. The driven part is driven by a magnetic force with respect to the piston, and has a penetrating part that penetrates the cylinder tube.However, since there is no need to provide a slit as in the conventional case, a conventional cylinder having a slit is used. Its strength is increased compared to tubes. In addition, the guide rail often has a groove-shaped recess and is formed in a substantially U-shaped cross section, but since the guide rail has a length that covers the entire length of the reciprocating motion of the driven portion, the guide rail is relatively short. The strength of the guide arm is higher than that of the guide arm. Therefore, even when an external force acts, the driven portion and the guide rail are less likely to be deformed, and play is less likely to occur in the bearing structure.

Further, in the rodless cylinder according to the first aspect of the present invention having the above-described structure, guide grooves for inner load balls are provided on both side surfaces of a driven portion having a through portion through which the cylinder tube is inserted. In addition, guide grooves for outer load balls are provided on both inner side surfaces of the groove-shaped concave portion provided on the guide rail, and a large number of ball-shaped rolling elements are provided between the two pairs of guide grooves facing each other. Since it is freely interposed, the cylinder tube inserted through the penetrating part of the driven part and the guide rail that guides the reciprocating motion of the driven part through the rolling elements are arranged to overlap vertically. Therefore, compared to a conventional rodless cylinder in which a cylinder tube and a guide rail are arranged in parallel in the width direction, the installation space in the width direction can be reduced.

In addition to the above, in the rodless cylinder according to the second aspect of the present invention having the above-mentioned structure, the endless circulation path for rotatably accommodating a large number of ball-shaped rolling elements is formed on the side surface of the driven table. And a guide groove for an outer load ball formed on the inner side surface of a recess provided in the guide rail, and a circulation path formed on an end cover fixed to an end face of the driven table. , And a combination with a guide hole for a no-load ball formed inside the driven table.
A straight guide groove for the inner loaded ball is formed over the entire length of the driven table together with the guide hole for the unloaded ball. Therefore, the length of the guide groove for the inner load ball is set relatively long, and a number of rolling elements can be arranged here, so that the rigidity and accuracy of the bearing structure can be further improved.

[0016] In addition, in the rodless cylinder according to the third aspect of the present invention having the above-described structure, the end cover is fixed to the driven table by a bolt, and the head of the bolt is attached to the driven table. It functions as a shock absorber that regulates the end position of the movement so as to be adjustable or a stopper receiver that contacts the stopper. Accordingly, the shock absorber or the stopper is accordingly arranged on the extension of the reciprocating direction of the driven table, so that even if the shock absorber or the stopper is provided, the installation space in the width direction of the rodless cylinder is increased. Nothing.

In the rodless cylinder according to the fourth aspect of the present invention, the end cover is fixed to the driven table by a bolt, and the head of the bolt moves the driven table to a predetermined position. It functions as an object to be detected by a sensor or a switch which sends a signal to the outside by detecting the fact. Accordingly, since the sensor or the switch is arranged on the extension of the reciprocating direction of the driven table, the installation space in the width direction of the rodless cylinder may be expanded even if the sensor or the switch is provided. Absent.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front view of a rodless cylinder according to the embodiment, FIG. 2 is a partially cutaway plan view, FIG. 3 is an enlarged right side view, FIG. 4 is an enlarged sectional view taken along line AA in FIG. FIG. 5 is a sectional view taken along line BB in FIG. 1, and FIG. 6 is an enlarged sectional view of the piston.

Guide rail (also referred to as guide rail) 1
End plates 2 are fixed to both ends in the longitudinal direction, respectively, and a cylinder tube 3 is installed between the pair of end plates 2 in parallel with the guide rail 1. A piston 4 is inserted inside the cylinder tube 3 so as to be able to reciprocate, and a driven portion 5 driven by the piston 4 is inserted into the cylinder tube 3. A linear bearing (also referred to as a linear ball bearing) 6 is provided between 5 and the guide rail 1. The guide rail 1, the pair of end plates 2, and the cylinder tube 3 are provided together with the fixed portion 7 on the installation side of the rodless cylinder.
Has formed.

As shown in FIG. 6, a piston 4 has an annular magnetic pole member 9 and an annular permanent magnet 10 between a pair of nonmagnetic piston members 8 in the axial direction.
Are alternately arranged, a tie rod 11 made of a non-magnetic material is inserted in the center, and nuts 12 are tightened from both ends to integrate these components. The permanent magnets 1 arranged in the axial direction with the magnetic pole member 9 interposed therebetween
0 makes the same poles face each other in the axial direction. A piston seal 13 and a wear ring 14 are attached to the outer periphery of one of the piston members 8 on the left side in the figure, and an O-ring 15 is attached to the inner periphery. A wear ring 16 is mounted on the outer periphery of the other piston member 8 on the right side in the drawing, and an O-ring 17 is mounted on the inner periphery.

The cylinder tube 3 in which the piston 4 is inserted so as to be reciprocally movable is formed of a non-magnetic material into a cylindrical shape. End covers 18 are respectively fitted to both ends of the cylinder tube 3, and the end covers 18 are fitted to the end plates 2, respectively. Each of the end covers 18 has O-rings 19 and 20 mounted on its outer periphery, and a passage 21 penetrating in the axial direction is provided inside. Each of the end plates 2 is provided with a piping port 22 communicating with the passage 21.

The driven portion 5 includes a driven table 23 having a substantially rectangular shape and a pair of end covers 24 fixed to both ends of the driven table 23, respectively.
Is provided with a through-hole 25 having a circular cross section in which the cylinder tube 3 is inserted so as to be relatively displaceable. The driven table 23 is formed of a magnetic material into a substantially rectangular shape, and the end covers 24 are formed of resin. The end cover 24 is fixed to the driven table 23 by two reamer bolts 26 each.
A metal guide ring 27 is interposed between the end cover 24 and the reamer bolt 26 so that the resin end cover 24 is not destroyed by the tightening.

The penetrating portion 2 inside the driven table 23
5, the same number of magnetic pole members 28 as the number of magnetic pole members 9 are provided facing the magnetic pole members 9, and the magnetic pole portions 28 are provided at both axial ends of the magnetic pole member group. It is kept coaxial with the cylinder tube 3 and the magnetic pole portion 28
A wear ring 29 for maintaining a predetermined interval between the cylinder and the cylinder tube 3 is mounted. Magnetic pole member 9 and magnetic pole portion 28
Are attracted to each other by a magnetic force, so that the driven portion 5 is driven by the piston 4 that is moved by being pressed by the compressed air supplied into the cylinder tube 3. End cover 2
A scraper 30 for preventing external dust from entering the magnetic pole portion 28 is provided on the periphery of the opening of the through portion 25 in FIG.
Are mounted so as to slide on the outer peripheral surface of the cylinder tube 3.

The linear bearing 6 is configured as follows.

First, guide grooves 31 for inner load balls are provided on both side surfaces of the driven table 23, and a pair of guide holes 32 for non-loaded balls are formed inside the driven table 23. And are provided in parallel. The guide groove 31 for the inner load ball is provided linearly over the entire length of the driven table 23, and has a substantially arc-shaped cross section. The no-load ball guide hole 32 is provided linearly over the entire length of the driven table 23, and has a substantially circular cross section.

On the upper surface of the guide rail 1, a groove-like concave portion 33 for reciprocatingly receiving the lower portion of the driven portion 5 is provided over the entire length of the guide rail 1. This concave portion 3 facing in parallel at a distance of
Guide grooves 3 for outer load balls on both inner side surfaces of
4 is provided so as to face the guide groove 31 for the inner load ball. The outer load ball guide groove 33 is provided over the entire length of the guide rail 1, and has a substantially arc-shaped cross section. A hole-shaped circulation path 35 for connecting the inner load ball guide groove 31 and the no-load ball guide hole 32 is provided inside each of the pair of end covers 24 fixed to the end of the driven table 23. I have. The circulation path 35 has a substantially U-shaped plane, and is formed to have a substantially circular cross section.

The guide groove 31 for the inner load ball, the guide groove 34 for the outer load ball, the circulation path 35, and the endless circulation path 36 formed by the guide hole 32 for the no-load ball,
A large number of ball-shaped rolling elements 37 are rotatably and densely accommodated in the parallel direction with substantially no gap. The infinite circulation path is 36,
A straight path comprising an inner load ball guide groove 31 and an outer load ball guide groove 34;
And a pair of circulation paths 35 that endlessly connect the two straight paths. Each of the inner load ball guide groove 31, the outer load ball guide groove 34, and the rolling element 37 is subjected to heat treatment to obtain a predetermined hardness, and then ground to have a precise size and shape. Have been.

A screw hole 38 is provided in each of the pair of end plates 2, and a shock absorber 39 is screwed into each of the screw holes 38 toward the driven portion 5 so as to be able to advance and retreat. Each of the shock absorbers 39 is disposed substantially coaxially with the left and right reamer bolts 26 on the upper side in FIG. 5, so that the heads of the reamer bolts 26 regulate the movable end position of the driven table 23 so as to be adjustable. It functions as a stopper receiver that comes into contact with the shock absorber 39. Alternatively, the shock absorber 39 may be a bolt-shaped stopper having no cushioning function.

A second screw hole 40 is provided in each of the pair of end plates 2, and a proximity sensor 41 is screwed into the screw hole 40 so as to be able to advance and retreat toward the driven portion 5. Each of the proximity sensors 41 is disposed substantially coaxially with the left and right reamer bolts 26 on the upper and lower sides in FIG. 5, so that the heads of the reamer bolts 26 detect that the driven table 23 has moved to the movement end position. And functions as a detection target of the proximity sensor 41 that sends a signal to the outside. The proximity sensor 41 may be a limit switch instead.

When the rodless cylinder is used in an environment where there is a lot of dust or the like, a dust seal (not shown) is provided on the driven table 23 and the end cover 24 to prevent dust from interfering with the rolling portion of the rolling element 37. Is preferred.

The driven table 23 is provided with a required number of taps 42 on its upper surface, and this upper surface is used as a mounting surface for mounting works, tools, and the like. However, the driven table 23 is accommodated in the recess 33 of the guide rail 1 with only its lower part floating, and most of the rest is in the recess 3.
3 is protruding outside. Therefore, by newly providing a tap (not shown) on the side surface protruding from the concave portion 33, the side surface can be used as a mounting surface.

Next, the operation of the rodless cylinder having the above configuration will be described.

FIG. 5 shows that a compressed air supply source and a switching valve (not shown) are compressed into a right cylinder chamber 43 in the cylinder tube 3 defined by the piston 4 via a piping port 22 and a passage 21 on the right side in the figure. A state is shown in which air is supplied, and the cylinder chamber 44 on the opposite side, that is, the left side is opened to the atmosphere via the left side passage 21, the piping port 22, and the switching valve. In this state, the piston 4 is pressed leftward by the compressed air, and the driven table 23 driven by the piston 4 is driven.
Is stopped when the head of the upper left reamer bolt 26 contacts the upper left shock absorber 39. The lower left proximity sensor 41 also detects the head of the lower left reamer bolt 26, and a signal that the driven table 23 is stopped at one of the movement end positions is transmitted to the outside by a signal. When an external force acts on the driven table 23 in this state, the driven table 23, the cylinder tube 3, the guide rail 1, and the like are not deformed because the linear bearing 6 strongly supports the external force. In addition, even when the linear bearing 6 supports the external force, the driven table 23 can smoothly move relative to the guide rail 1 via the linear bearing 6.

Next, by switching a switching valve (not shown), compressed air is supplied to the left cylinder chamber 44 through the piping port 22 and the passage 21 on the left side of the drawing, and the right cylinder chamber 43 is connected to the right passage 21, When the air is released to the atmosphere via the piping port 22 and the switching valve, the piston 4 is pressed rightward by the compressed air, and the driven table 23 is simultaneously driven rightward. In the driven table 23, the head of the reamer bolt 26 on the upper right is the same as the shock absorber 39 on the upper right.
At this time, the head of the lower right reamer bolt 26 is also detected by the lower right proximity sensor 41, and a signal that the driven table 23 has stopped at the other end position of movement is transmitted to the outside by a signal. . When an external force acts on the driven table 23 in this state, the linear bearing 6 strongly supports the external force.
There is no deformation of the cylinder tube 3 or the guide rail 1 or the like. In addition, even when the linear bearing 6 supports the external force, the driven table 23 can smoothly move relative to the guide rail 1 via the linear bearing 6.

The rodless cylinder is characterized in that the following effects are achieved by the above-described configuration.

That is, first, in the rodless cylinder having the above structure, the guide groove 31 for the inner load ball is provided on each of both side surfaces of the driven table 23 and the groove-shaped concave portion provided on the guide rail 1. Outer load ball guide grooves 34 are provided on both inner side surfaces of the pair 33, respectively. A large number of ball-shaped rolling elements 37 are respectively rotatably interposed between the two pairs of guide grooves 31, 34 facing each other. Thus, a linear bearing 6 is formed. The driven table 23 is driven by the magnetic force with respect to the piston 4 and has a hole-shaped through portion 25 through which the cylinder tube 3 is inserted. However, since there is no need to provide a slit as in the related art, Its strength is increased compared to a conventional cylinder tube having a slit. The guide rail 1 has a groove-shaped concave portion and is formed in a substantially U-shaped cross section. However, since the guide rail 1 has a length corresponding to the entire length of the reciprocating motion of the driven table 23, the length is relatively short. The strength of the guide arm is higher than that of the guide arm. Therefore, even if an external force acts, the driven table 23 and the guide rail 1 are hardly deformed, and the linear bearing 6 is hardly rattled. Therefore, it is possible to provide a rodless cylinder in which the driven table 23 reciprocates with high accuracy for a long period of time. If the driven table 23 and the guide rail 1 are hard to deform, the cylinder tube 3 does not deform, and the life of the piston 4 and the piston seal 13 is extended.

Further, in addition to the above, in the rodless cylinder having the above structure, a large number of ball-shaped rolling elements 3 are provided.
Endless circulating path 36 for rotatably accommodating therein the inner load ball guide groove 31 formed on the side surface of the driven table 23.
A guide groove 34 for an outer load ball formed on an inner side surface of a concave portion 33 provided in the guide rail 1;
Circulation path 35 formed in the end cover 24 fixed to the end face 3
And a guide hole 32 for a no-load ball formed in the driven table 23. In the driven table 23, a guide groove 31 for a straight inner load ball is provided. The guide hole 32 and the driven table 23 are formed over the entire length of the driven table 23. Therefore, the length of the guide groove 31 for the inner load ball is set relatively long, and since a large number of the rolling elements 37 are arranged here, the rigidity and accuracy of the linear bearing 6 can be further improved. The substantially rectangular driven table 23 and the guide rail 1 having a substantially U-shaped cross section have a small distortion due to quenching and are relatively easy to correct.
The production cost does not increase as compared with a normal linear bearing.

In addition to the above, in the rodless cylinder having the above structure, the guide grooves for inner load balls are respectively formed on both side surfaces of the driven table 23 having the hole-shaped through portion 25 through which the cylinder tube 3 is inserted. In addition, an outer load ball guide groove 34 is provided on each of both inner side surfaces of a groove-shaped concave portion 33 provided on the guide rail 1, and between the two pairs of guide grooves 31, 34 facing each other. Since a large number of ball-shaped rolling elements 37 are rotatably interposed to constitute the linear bearing 6,
The cylinder tube 3 inserted into the through portion 25 of the driven table 23 and the guide rail 1 for guiding the reciprocating motion of the driven table 23 via the linear bearing 6 are arranged so as to overlap vertically. Therefore, the installation space in the width direction can be reduced as compared with the conventional rodless cylinder in which the cylinder tube and the guide rail are arranged in parallel in the width direction.

In addition, in the rodless cylinder having the above-described structure, the end cover 24 is fixed to the driven table 23 by the reamer bolt 26, and the head of the reamer bolt 26 serves as the moving end of the driven table 23. It functions as a stopper receiver that comes into contact with the shock absorber 39 that regulates the position to be adjustable. Therefore, since the shock absorber 39 is disposed on an extension of the driven table 23 in the reciprocating direction, the installation space in the width direction of the rodless cylinder does not increase even if the shock absorber 39 is provided. Therefore, it is possible to provide a still smaller rodless cylinder having the additional function of the shock absorber 39.

In addition, in the rodless cylinder having the above-described structure, the end cover 24 is fixed to the driven table 23 by the reamer bolt 26, and the head of the reamer bolt 26 is fixed to the driven table 23 by a predetermined amount. It functions as an object to be detected by the proximity sensor 41 that detects that it has moved to the position and sends a signal to the outside. Therefore, since the proximity sensor 41 is disposed on an extension of the driven table 23 in the reciprocating direction, even if the proximity sensor 41 is provided, the installation space in the width direction of the rodless cylinder does not increase. Therefore, it is possible to provide a small-sized rodless cylinder having the additional function of the proximity sensor 41.

In addition, in the rodless cylinder having the above structure, the upper surface of the driven table 23 is a mounting surface (mounting surface) for a work or a tool, so that the mounting surface becomes wider. The degree of freedom in equipment design can be improved. In addition, since the driven table 23 has surfaces on both sides of which taps can be cut, the use of these both sides as mounting surfaces can further improve the degree of freedom in equipment design.

[0043]

The present invention has the following effects.

That is, in the rodless cylinder according to the first aspect of the present invention having the above-described structure, guide grooves for inner load balls are provided on both side surfaces of the driven portion, respectively, and the groove-shaped grooves provided on the guide rail are provided. Guide grooves for outer load balls are respectively provided on both inner side surfaces of the concave portion, and a large number of ball-shaped rolling elements are rotatably interposed between the two pairs of guide grooves facing each other. The driven part is driven by a magnetic force with respect to the piston, and has a penetrating part that penetrates the cylinder tube.However, since there is no need to provide a slit as in the conventional case, a conventional cylinder having a slit is used. Its strength is increased compared to tubes. In addition, the guide rail often has a groove-shaped recess and is formed in a substantially U-shaped cross section, but since the guide rail has a length that covers the entire length of the reciprocating motion of the driven portion, the guide rail is relatively short. The strength of the guide arm is higher than that of the guide arm. Therefore, even when an external force acts, the driven portion and the guide rail are less likely to be deformed, and the bearing structure is less likely to rattle. Therefore, it is possible to provide a rodless cylinder in which the driven portion continuously reciprocates with high precision for a long period of time. If the driven portion and the guide rail are not easily deformed, the cylinder tube will not be deformed, and the life of the piston and the piston seal will be extended.

Further, in the rodless cylinder according to the first aspect of the present invention having the above-mentioned structure, guide grooves for inner load balls are provided on both side surfaces of a driven portion having a through portion through which the cylinder tube is inserted. In addition, guide grooves for outer load balls are provided on both inner side surfaces of the groove-shaped concave portion provided on the guide rail, and a large number of ball-shaped rolling elements are provided between the two pairs of guide grooves facing each other. Since it is freely interposed, the cylinder tube inserted through the penetrating part of the driven part and the guide rail that guides the reciprocating motion of the driven part through the rolling elements are arranged to overlap vertically. Therefore, the installation space in the width direction can be reduced as compared with the conventional rodless cylinder in which the cylinder tube and the guide rail are arranged in parallel in the width direction.

In addition to the above, in the rodless cylinder according to the second aspect of the present invention having the above structure, the endless circulation path for rotatably accommodating a large number of ball-shaped rolling elements is formed on the side surface of the driven table. And a guide groove for an outer load ball formed on the inner side surface of a recess provided in the guide rail, and a circulation path formed on an end cover fixed to an end face of the driven table. , And a combination with a guide hole for a no-load ball formed inside the driven table.
A straight guide groove for the inner loaded ball is formed over the entire length of the driven table together with the guide hole for the unloaded ball. Therefore, since the length of the guide groove for the inner load ball is set relatively long, and a large number of rolling elements can be arranged here, the rigidity and accuracy of the bearing structure can be further improved.

In addition, in the rodless cylinder according to the third aspect of the present invention having the above-described structure, the end lid is fixed to the driven table by a bolt, and the head of the bolt is attached to the driven table. It functions as a shock absorber that regulates the end position of the movement so as to be adjustable or a stopper receiver that contacts the stopper. Accordingly, the shock absorber or the stopper is accordingly arranged on the extension of the reciprocating direction of the driven table, so that even if the shock absorber or the stopper is provided, the installation space in the width direction of the rodless cylinder is increased. Nothing. Therefore, it is possible to provide a still smaller rodless cylinder having the additional function of the shock absorber or the stopper.

In the rodless cylinder according to the fourth aspect of the present invention having the above structure, the end cover is fixed to the driven table by a bolt, and the head of the bolt moves the driven table to a predetermined position. It functions as an object to be detected by a sensor or a switch which sends a signal to the outside by detecting the fact. Accordingly, since the sensor or the switch is arranged on the extension of the reciprocating direction of the driven table, the installation space in the width direction of the rodless cylinder may be expanded even if the sensor or the switch is provided. Absent. Therefore, it is possible to provide a still smaller rodless cylinder having the additional function of a sensor or a switch.

[Brief description of the drawings]

FIG. 1 is a front view of a rodless cylinder according to an embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of the rodless cylinder.

FIG. 3 is an enlarged right side view of the rodless cylinder.

FIG. 4 is an enlarged sectional view taken along line AA in FIG. 1;

FIG. 5 is a sectional view taken along line BB in FIG. 1;

FIG. 6 is an enlarged sectional view of a piston.

FIG. 7 is a front view of a rodless cylinder according to a conventional example.

FIG. 8 is an enlarged sectional view taken along line CC in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Guide rail 2 End plate 3 Cylinder tube 4 Piston 5 Follower 6 Linear bearing 7 Fixed part 9 Magnetic pole member 10 Permanent magnet 13 Piston seal 23 Follower table 24 End cover 25 Penetration 26 Reamed bolt (bolt) 28 Magnetic pole 31 Internal load ball Guide groove 32 No-load ball guide hole 33 Recess 34 Outer load ball guide groove 35 Circulation path 36 Infinite circulation path 37 Rolling element 39 Job absorber 41 Proximity sensor (sensor)

Claims (4)

[Claims] Cylinder tube made of non-magnetic material (3)
A piston (4) reciprocating in the cylinder tube (3) by the supply of fluid pressure and having a required number of permanent magnets (10); and a through portion (25) inserted through the cylinder tube (3). )
A driven portion (5) reciprocating in accordance with the piston (4) by the magnetic force of the permanent magnet (10), and having a guide groove (31) for an inner load ball on each side surface; ) Along the reciprocating direction of the groove (3).
3) a guide rail (1) provided on both inner side surfaces of the concave portion (33) with guide grooves (34) for outer load balls so as to face the guide grooves (31) for inner load balls, A number of ball-shaped rolling elements (37) rotatably accommodated in an infinite circulation path (36) including a straight path composed of the inner load ball guide groove (31) and the outer load ball guide groove (34). And a rodless cylinder. 2. A cylinder tube made of a non-magnetic material (3).
A piston (4) reciprocating in the cylinder tube (3) by the supply of fluid pressure and having a required number of permanent magnets (10); and a through portion (25) inserted through the cylinder tube (3). )
And reciprocates according to the piston (4) by the magnetic force of the permanent magnet (10), and has guide grooves (31) for inner load balls on both sides, and a pair of guide holes (32) for non-load balls inside. ) Parallel to the inner load ball guide groove (31), and a driven table (23) fixed to both end surfaces of the driven table (23), and the inner load ball guide groove (31) inside. And the circulation path (3) connecting the no-load ball guide hole (32).
5) a pair of end lids (24), and a groove-like recess (33) along the reciprocating direction of the driven table (23), and external loads on both inner side surfaces of the recess (33). A guide rail (1) having a ball guide groove (34) facing the inner load ball guide groove (31); an inner load ball guide groove (31); and an outer load ball guide groove (31). 34), a number of ball-shaped rolling elements (37) rotatably accommodated in an infinite circulation path (36) comprising a circulation path (35) and a guide hole (32) for a no-load ball. And a rodless cylinder. 3. The rodless cylinder according to claim 2, wherein an end cover (24) is attached to the driven table (23) by a bolt (26).
The head of the bolt (26) is fixed to the driven table (2
3) A rodless cylinder characterized in that it is a shock absorber (39) that regulates the movement end position in an adjustable manner or a stopper receiver that comes into contact with a stopper. 4. The rodless cylinder according to claim 2, wherein an end cover (24) is attached to the driven table (23) by a bolt (26).
The head of the bolt (26) is fixed to the driven table (2
3) A rodless cylinder characterized in that it is used as a sensor (41) or an object to be detected by a switch, which detects that the device has moved to a predetermined position and sends a signal to the outside.