JP2613337B2 - Rodless cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rodless cylinder which can operate smoothly without being particularly affected by a horizontal load.

[0002]

2. Description of the Related Art In recent years, various types of rodless cylinders have been adopted as a work transfer device in a factory or the like.

[0003] The rodless cylinder can shorten the stroke length as compared with a cylinder having a rod, and therefore occupies a small area and is easy to handle. In addition, dust and the like can be prevented from entering the cylinder as compared with a cylinder having a rod, and as a result, a high-level positioning operation and the like can be performed.

For example, US Pat. No. 4,373,427 or German Patent 3,124,915 discloses such a rodless cylinder. In particular, German Patent 31249
In the rodless cylinder according to No. 15, a guide groove is provided between the outer peripheral surface of the cylinder tube and the upper surface of the cylinder in which the slit is defined, and a leg extending from both ends of the slide table to the cylinder tube side in the guide groove. It is configured such that different guide means provided on the portion are engaged. According to German Patent No. 3124915, when a lateral force is applied, the guide means are engaged with each other to prevent the slit from widening.

[0005]

However, according to the above-mentioned German Patent 3,124,915, it is necessary to extend the legs from the slide table further outward than the outer surface of the cylinder tube, and to hold the guide means. Therefore, when the guide means are engaged with each other when a lateral force is applied, one end face of the cylinder tube forcibly defining the slit is forced to the other end face of the cylinder tube for defining the mating slit. And the bore diameter is reduced as a whole, forcing the piston to stop. That is, it has been pointed out that the application of a lateral force causes a stop state of the piston, which unexpectedly stops the transfer action on the work, which is extremely dangerous.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and in particular, it is possible to prevent the bore diameter from being reduced even when a lateral force acts on the slide table. It is an object of the present invention to provide a rodless cylinder capable of smoothly reciprocating the slide table without causing the slide table.

[0007]

In order to achieve the above object, the present invention comprises a cylinder and a slide table, and the cylinder reciprocates in a cylinder tube and a bore defined in the cylinder tube. A slit extending in the longitudinal direction of the cylinder tube and communicating the outside with the bore, the slit being associated with a first seal member engaged with the piston and the slide table. is closed by a second sealing member that case, the said cylinder tube and the slide table, a vertical load acting on the piston of the reciprocating guides the slide table during operation and said sliding table
Second bearing at the first holding mechanism and a horizontal direction which is supported in a direction
In addition to providing a holding mechanism, the cylinder tube
With the slit on one side of the ride table side,
In the direction crossing the virtual vertical plane passing through the axis of the tube
An extended set of recesses is defined and the slide table
Extension direction of the set of recesses on one surface of the cylinder tube side
Forming a protruding portion extending in the same direction as the
Section is provided with the second holding mechanism, and the slide table
When a horizontal force is applied, the second holding mechanism moves
It is characterized in that the bore diameter of the cylinder is supported in the direction of increasing the bore diameter .

[0008]

According to the rodless cylinder of the present invention, the load acting on the slide table is supported to reduce the bore inner diameter.
A first holding mechanism and a second holding mechanism capable of preventing a reduction in diameter are provided. For example, when a force is applied to the slide table in a vertical direction, the force is received by the first holding mechanism. When a force acts in the direction, the force can be received by the second holding mechanism.
Therefore, even if the lateral force is applied particularly unexpected, cut with reliably prevented that the bore inner diameter is reduced.

[0009]

1, a reference numeral 10 indicates a rodless cylinder according to a first embodiment of the present invention. The rodless cylinder 10 has a cylinder tube 12 and a slide table 14. It has a bore 16 extending in the longitudinal direction inside the cylinder tube 12 (see FIG. 2),
The bore 16 is in communication with the outside through a slit 18 defined in the end face. As shown in FIG. 3, the sensor mounting elongated grooves 20a and 20b and the lead wire storing elongated grooves 2 extend in the longitudinal direction on both side surfaces of the cylinder tube 12.
0c and 20d are defined, and fluid bypass passages 22a and 22b for the centralized piping are similarly defined to extend in the longitudinal direction.

[0010] In FIG. 3, the upper surface 24a, 24b is provided along the horizontal direction on <br/> portion of the cylinder tube 12,
The upper surface 24a, a first recess by cutting the inner side of 24b 2
8. The second recess 30 is formed. The side surfaces 32a, 32b defining the first and second concave portions 28, 30 are formed at a predetermined angle, for example, 45 degrees, opposite to each other with respect to the vertical direction.
° is inclined.

The slit 18 communicates the bore 16 with the outside as described above. The side walls defining the slit 18 have stepped portions 36a, 36b so as to expand toward the bore 16.
Is provided. The surface extending upward from the inner side surface of the slit 18 is configured as a horizontal plane, and once it becomes vertical, the first and second concave portions 28, 3
Connects to 0.

Both ends of the cylinder tube 12 configured as described above are hermetically closed by end caps 40a, 40b in which ports 38a, 38b are defined (see FIG. 1).

Next, the slide table 14 will be described. As shown in FIGS. 3 and 4, the slide table 14 includes a relatively thick U-shaped plate 44, and both short-side ends 46 a and 46 b of the plate 44 are closer to the end of the cylinder tube 12. The end faces 48a, 48 protrude outward and surround the end of the cylinder tube 12.
b is disposed below the upper surfaces 24a and 24b of the cylinder tube 12. A magnetic sensor (position detection sensor) 50 for detecting the position of the slide table 14 is attached to a long groove 20 b provided on the side surface of the cylinder tube 12, and an end 46 of the slide table 14.
b, a magnetic body (driving body) 51 for driving the magnetic sensor 50 is disposed to face the magnetic sensor 50.

In FIG. 3, the lower surface of the slide table 14, the upper surfaces 24a and 24b of the cylinder tube 12 and the first
The slide table 14 is guided by the recess 28 and the second recess 30 during the reciprocating operation of the piston (described later), and the load acting on the slide table 14 is supported to prevent the inner diameter of the bore 16 from being reduced. A first holding mechanism 52 and a second holding mechanism 54 are provided. This first holding mechanism 5
The second holding mechanism 54 is capable of supporting a load acting on the slide table 14 in a vertical direction, while the second holding mechanism 54 is capable of supporting a load acting on the slide table 14 in a vertical direction. is there.

The first holding mechanism 52 includes a slide table 1
A plurality of rods 55a and 55b fixed to the lower surface of the rod 4 in a horizontal direction, and a guide roller (rotary body) 56 rotatably mounted on the distal ends of the rods 55a and 55b.
a, 56b and the upper surface 24a, 2b of the cylinder tube 12;
Rail members 58a, 58b fixed to the base member 4b and on which the guide rollers 56a, 56b roll. The position of the rolling surface (rolling portion) T between the guide rollers 56a and 56b and the rail members 58a and 58b is opposite to the bore 16 side with respect to the slit position S where the slit 18 is provided (in FIG. 3, (Upward) with a distance H1. On the other hand, the end surfaces 48a and 48b of the slide table 14 protrude below the rolling surface T by a distance H2 to prevent dust and the like from entering the rolling surface T from the lateral direction.

The second holding mechanism 54 includes a slide table 1
4, projections 59 a and 59 b formed at an angle of 45 ° in directions opposite to each other (in the direction away from each other in FIG. 3) with respect to the vertical direction.
9b, a plurality of rods 55c, 55d, guide rollers 56c, 56d rotatably mounted on the distal ends of the rods 55c, 55d, and the cylinder tube 12
The guide rollers 5 are fixed to the side surfaces 32a and 32b of the
Rail members 58c and 58d on which 6c and 56d roll. A slit 60 is formed in the protrusion 59b by cutting into the inside of the slide table 14, and the bolt 61 is inclined from the upper surface side of the slide table 14 and screwed into the protrusion 59b. The position of the guide roller 56d is adjustable in a direction intersecting with the axial direction.

A groove 62 extending in the longitudinal direction is defined through the center of the slide table 14, and the center of the groove 62 expands in a circular shape to form a space 64. Groove 62
As shown in FIG. 4, the plate body 44 has a curved concave portion 66 directed to the surface 44 a of the plate body 44 shown in FIG. 3 on the side opposite to the cylinder tube 12.

FIG. 5 shows the piston 70. The piston 70 includes a first pressure receiving surface 72 and a second pressure receiving surface 74 on the opposite side.
And cushion seals 76a, 76b inside thereof.
Is provided (see FIG. 6). Cylindrical piston 70
Belt separators 78a and 78b are fixed to the piston yoke 80 at the upper part of the piston yoke 80.
A roller 84 is fixed via a coupler 82 to the upper side. As shown in FIG. 6, in the inside of the slide table 14, scraper 84a, and 84b are provided, the coupler 82, the circular space has a planar circular shape 6
4. In FIG. 6, reference numeral 86 indicates a passage for a first seal member described later to enter the piston, and reference numeral 87 indicates a cushion ring.

FIG. 7 shows a seal member fitted to the steps 36a and 36b. The first sealing member 90 includes tongue pieces 92a, 92
b, and bulges 94a, 94b are further provided above the tongue pieces 92a, 92b. The bulges 94a, 9
The engagement piece 9 is directed upward from the base 4b so as to slightly expand.
6a and 96b extend. The bulging portions 94a, 94
b is for engaging the step portions 36a, 36b when an internal pressure is applied to the inside of the piston 70, and the engaging pieces 96a, 96b are further provided with inner surfaces 98a, 98b for defining the slit 18. Engages. This first seal member 9
Numeral 0 is integrally formed of a flexible synthetic resin body as a whole. On the other hand, the second sealing member 97
And is fitted into a groove 99 extending in a longitudinal direction from above a slit defined on the upper end surface of the cylinder tube 12. The first seal member 90 is
It penetrates into the passage 86 of the piston 70, and both ends thereof are
End caps 40a and 40b together with the sealing member 97
It is stuck to.

Next, the operation of the rodless cylinder 10 configured as described above will be described.

First, as shown in FIG. 3, after the cylinder tube 12 is arranged, the surface 44 of the slide table 14 is
The work is fixed to a. When compressed air is introduced from the port 38a, the compressed air presses the first pressure receiving surface 72 through a passage defined inside the cushion ring 87. Thereby, the piston 70 is displaced to the left (in the direction of arrow X) in FIG. At this time, the piston 70 is connected to the space 82 of the slide table 14 by the coupler 82.
, The slide table 14 is displaced integrally and is similarly moved to the left. At this time,
The belt separators 78a and 78b are connected to the first seal member 9
0 and the second sealing member 97 with the slide table 1
4. It acts to separate the piston 70 from each other. Therefore, the work placed on the slide table 14 is
Can be transported to the left. Port 38b
When compressed air is introduced into the air, the opposite operation is performed.

The roller 84 slides on the second seal member 97 during the transfer to facilitate the transfer.

In FIG. 3, when a relatively heavy work is fixed to the slide table 14, a vertical load F1 acts on the slide table 14.
Guide rollers 56a, 56 constituting the first holding mechanism 52
b and the rail members 58a, 58b, the vertical load F
1 can be effectively received. Furthermore, even if an unexpected load F2 is applied to the slide table 14 in the lateral direction,
Guide rollers 56c, 56d and rail members 58c, 58d which constitute the second holding mechanism 54 and are inclined with respect to the vertical direction
Thus, the load F2 can be reliably received.

At this time, the guide rollers 56c and 56d constituting the second holding mechanism 54 engage the rail members 58c and 58d toward the outside of the bore 16 when the load F2 acts on the slide table 14. Therefore, even when an unexpected load is applied to the slide table 14, it is possible to avoid a situation in which the inner diameter of the bore 16 is reduced and the piston 70 is stopped as shown in the related art. The effect is obtained.

Furthermore, the position of the rolling surface T between the guide rollers 56a, 56b and the rail members 58a, 58b constituting the first holding mechanism 52 is opposite to the slit 18 on the side opposite to the bore 16 side (in FIG. 3, (Upward).
For this reason, there is no need to form a bulging portion by protruding the guide rollers 56a and 56b largely downward from the slide table 14 so that the guide rollers 56a and 56b protrude toward the bore 16, and the entire slide table 14 is effectively formed to be thin. And the shape is simplified.

Next, a rodless cylinder 100 according to a second embodiment of the present invention will be described with reference to FIG. In addition,
The same reference numerals as those of the rodless cylinder 10 according to the first embodiment denote the same components, and a detailed description thereof will be omitted.

The rodless cylinder 100 has first and second holding mechanisms 102 and 104, and the first holding mechanism 102
Step-shaped synthetic resin body (wear-resistant portion) 1 fixed to 4b
06a, 106b and the synthetic resin bodies 106a, 106b
And sliding surfaces 108a and 108b slidingly in contact with each other. The synthetic resin bodies 106a and 106b and the sliding surfaces 108a and
The position of the sliding surface (sliding portion) P with respect to the slit 8b is set at a distance H1 on the side opposite to the bore 16 side with respect to the slit position S.

The second holding mechanism 104 is composed of synthetic resin bodies (abrasion resistant parts) 110a, 110b having an arc-shaped cross section which are fixed to the side surfaces 32a, 32b of the cylinder tube 12, and circles which are in sliding contact with the synthetic resin bodies 110a, 110b. Arc-shaped sliding surface 1
12a and 112b. This synthetic resin body 106
a, 106b, 110a, and 110b are formed of a material having excellent sliding characteristics and wear resistance.

Therefore, in the rodless cylinder 100, the first and second holding mechanisms 102 and 104 constitute a slide bearing, and the sliding surface 10 of the slide table 14
8a and 108b and the sliding surfaces 112a and 112b are made of the synthetic resin bodies 106a and 106b and the synthetic resin body 110.
a, the slide table 14 can be smoothly moved by sliding on the upper and lower surfaces 110a and 110b. The slide table 14 or the cylinder tube 12 can be used without using the synthetic resin bodies 106a, 106b, 110a, and 110b.
It is also possible to coat a desired portion with a wear-resistant surface treatment layer such as a synthetic resin film or hard alumite coating.

Further, a rodless cylinder 120 according to a third embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals as those of the rodless cylinder 100 according to the second embodiment denote the same components, and a detailed description thereof will be omitted.

The rodless cylinder 120 has a second holding mechanism 122 that can be adjusted in position in addition to the first holding mechanism 102.
Is provided. The second holding mechanism 122 includes a synthetic resin body 110a fixed to the side surface 32a of the cylinder tube 12 and a sliding surface 112a slidably contacting the same, and a synthetic resin body 110b fixed to the side surface 32b and a swinging slidable contact with the same. And a member 124.

The oscillating member 124 is arranged so as to be able to oscillate on the slide table 14 with the spherical portion 124a as a fulcrum, and an arc-shaped sliding surface 126 which is in sliding contact with the synthetic resin body 110b is formed at one end thereof. At the same time, the receiving member 127 is engaged with the other end. The receiving member 127 is a pressing screw 12 that is screwed into the slide table 14 in the horizontal direction.
8 is engaged.

Therefore, in this rodless cylinder 120, in addition to having the same effect as the rodless cylinder 100 described above, in particular, the swinging member 124 constituting the second holding mechanism 122 has a spherical shape under the pressing action of the pressing screw 128. Part 124
By swinging around the fulcrum a, the arc-shaped sliding surface 126 can be adjusted in position with respect to the synthetic resin body 110b.

Further, a rodless cylinder 130 according to a fourth embodiment of the present invention will be described with reference to FIG. The rodless cylinder 10 according to the first embodiment
The same reference numerals as those of the rodless cylinder 100 according to the second embodiment denote the same components, and a detailed description thereof will be omitted.

The rodless cylinder 130 includes first and second holding mechanisms 132 and 134. The first holding mechanism 132 particularly applies a vertical load F3 acting on the slide table 14 via a work (not shown). And has guide rollers 56a and 56b and rail members 58a and 58b. Second holding mechanism 13
4 has a function of guiding the slide table 14, and includes side surfaces 32a, 32b of the cylinder tube 12.
Arc-shaped synthetic resin bodies 110a, 110 fixed to the
and a sliding bearing comprising arc-shaped sliding surfaces 112a and 112b slidingly contacting the synthetic resin bodies 110a and 110b.

In the rodless cylinder 130 configured as described above, the guide rollers 56a, 5a and 5b correspond to the portions supporting the vertical load F3 acting on the slide table 14.
6b and the rail members 58a, 58b (that is, the rolling portions) are made corresponding to the other portions by the synthetic resin bodies 110a,
110b and sliding surfaces 112a and 112b (that is, sliding portions) are selectively provided. For this reason, as the second holding mechanism 134, the synthetic resin bodies 110a, 110b
By selectively using a relatively inexpensive sliding bearing composed of the sliding surface 112a and the sliding surface 112b, the load acting on the slide table 14 can be effectively supported and smooth movement can be performed. Less cylinder 1
The effect that the cost reduction of the whole 30 can be easily attained is obtained.

Next, a rodless cylinder 150 according to a fifth embodiment of the present invention will be described with reference to FIG. The same reference numerals as those of the rodless cylinder 10 according to the first embodiment and the rodless cylinder 100 according to the second embodiment denote the same components, and a detailed description thereof will be omitted.

The rodless cylinder 150 has a cylinder tube 12 suspended by a horizontal member 152, a work (not shown) mounted thereon, and a vertical load F4.
And a slide table 14 provided with a slide table. The cylinder tube 12 and the slide table 14 are provided with first and second holding mechanisms 154, 156. The first holding mechanism 154 includes step-shaped synthetic resin bodies 106a and 106b.
And sliding surfaces 108a and 108b that are in sliding contact with the synthetic resin bodies 106a and 106b.
The guide rollers 56c and 56d and the rail members 58c are provided to support the vertical load F4 acting on the slide table 14.
58d.

Therefore, in the rodless cylinder 150,
Rodless cylinder 130 according to the third embodiment described above
By using a sliding bearing for the first holding mechanism 154, the same effect as that of the rodless cylinder 130 can be obtained.

Further, a rodless cylinder 170 according to a sixth embodiment of the present invention will be described with reference to FIG. The same reference numerals as those of the rodless cylinder 10 according to the first embodiment and the rodless cylinder 100 according to the second embodiment denote the same components, and a detailed description thereof will be omitted.

In the rodless cylinder 170, since the load center overhangs the upper surface of the slide table 14 to dispose a work (not shown), a moment M is applied to the slide table 14 by the vertical load F5 of the work. Works. In order to support the moment M, first and second holding mechanisms 172 and 174 are provided.

The first holding mechanism 172 has a moment M
A guide roller 56a and a rail member 58a are provided corresponding to a portion supporting the sliding member, and a relatively inexpensive sliding bearing (sliding portion) comprising a synthetic resin body 106b and a sliding surface 108b is provided on the opposite side of the rolling portion. ) Is provided. On the other hand, the second
The holding mechanism 174 includes a guide roller 56d and a rail member 58d corresponding to a portion supporting the moment M,
A relatively inexpensive sliding bearing (sliding portion) comprising a synthetic resin body 110a and a sliding surface 112a is provided on the side opposite to the rolling portion.

Thus, the rodless cylinder 130,
In 150 and 170, various rolling parts are provided corresponding to the parts supporting the load acting on the slide table 14, and other parts are provided with sliding bearings which are relatively inexpensive sliding parts. Thus, the slide table 14 can be smoothly moved without being affected by the load, and the cost can be effectively reduced.

The rodless cylinders 130, 1
Reference numerals 50 and 170 are exemplarily shown. For example, even if the slide table 14 moves in the vertical direction or the state of attachment of the work is different, portions supporting the load acting on the slide table 14 are provided. The same effect can be obtained by providing a rolling part corresponding to the above, and adopting a sliding part in other parts.

[0045]

According to the present invention, even when load is applied excessively heavy lateral to the slide table as described above, it can be reliably prevented that the bore inner diameter is reduced, the slide table and piston A smooth operation is achieved without being stopped. Even if an unexpected lateral force is applied, the diameter of the slit is expanded by the second holding mechanism.
Since the directional force is supported, it is possible to effectively prevent the inner diameter of the bore from being reduced, and to prevent the piston from being stopped during the transfer of the workpiece.

[Brief description of the drawings]

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

FIG. 2 is an explanatory perspective view of a cylinder tube of the rodless cylinder.

FIG. 3 is a vertical sectional view of a slide table and a cylinder tube of the rodless cylinder.

FIG. 4 is an explanatory perspective view of a slide table constituting the rodless cylinder.

FIG. 5 is an explanatory perspective view of a piston of the rodless cylinder.

FIG. 6 is a side vertical sectional view of the rodless cylinder.

FIG. 7 is a partially omitted longitudinal sectional view showing an engagement state between a first seal member and a slit of the rodless cylinder.

FIG. 8 is a longitudinal sectional view of a rodless cylinder according to a second embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a rodless cylinder according to a third embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a rodless cylinder according to a fourth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of a rodless cylinder according to a fifth embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a rodless cylinder according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Rodless cylinder 12 ... Cylinder tube 14 ... Slide table 16 ... Bore 28, 30 ... Recess 52, 54 ... Holding mechanism 56a-56d ... Guide roller 58a-58d ... Rail member 70 ... Piston 100 ... Rodless cylinder 102, 104 ... holding mechanism 106a, 106b ... synthetic resin body 108a, 108b ... sliding surface 110a, 110b ... synthetic resin body 112a, 112b ... sliding surface 120 ... rodless cylinder 122 ... holding mechanism 124 ... swinging member 126 ... sliding surface 128: pressing screw 130: rodless cylinder 132, 134: holding mechanism 150: rodless cylinder 152, 154: holding mechanism 170: rodless cylinder 172, 174: holding mechanism

Continuation of the front page (56) References JP-A-1-247812 (JP, A) JP-A-63-190908 (JP, A) JP-A-2-186107 (JP, A) JP-A-1-210613 (JP) JP-A-58-163819 (JP, A) JP-A-1-121705 (JP, U) JP-A-60-182522 (JP, U) JP-A 64-45008 (JP, U) JP-A 58-89287 (JP, U)

Claims (10)

(57) [Claims] A cylinder and a slide table,
The cylinder has a cylinder tube and a piston that reciprocates in a bore defined in the cylinder tube, and defines a slit extending in the longitudinal direction of the cylinder tube to communicate the bore with the outside. The slit is closed by a first seal member that engages with a piston and a second seal member that engages with the slide table, and the slide table is provided between the cylinder tube and the slide table when the piston reciprocates. Information to and vertically the load acting on the slide table
Second bearing at the first holding mechanism and a horizontal direction which is supported in a direction
In addition to providing a holding mechanism, the cylinder tube
With the slit on one side of the ride table side,
In the direction crossing the virtual vertical plane passing through the axis of the tube
An extended set of recesses is defined and the slide table
Extension direction of the set of recesses on one surface of the cylinder tube side
Forming a protruding portion extending in the same direction as the
Section is provided with the second holding mechanism, and the slide table
When a horizontal force is applied, the second holding mechanism moves
A rodless cylinder characterized in that the bore diameter of the cylinder is supported in a direction to increase the bore diameter . 2. The rodless cylinder according to claim 1 , wherein the second holding mechanism includes a set of rail members and a set of rotating bodies.
And the set of rotating bodies is placed sideways on a slide table.
A rodless cylinder characterized in that when a load in the direction acts, the rodless cylinder rolls by pressing against the set of rail members toward the outside of the bore. 3. The rodless cylinder according to claim 1, wherein at least one of the rotating bodies constituting the first and / or second holding mechanism is configured to be position-adjustable in a direction intersecting the axial direction thereof. A rodless cylinder characterized in that: 4. The rodless cylinder according to claim 1, wherein an end crossing the moving direction of the slide table projects outward from an end of the cylinder tube and surrounds the end of the cylinder tube. A rodless cylinder characterized by being made. 5. The rodless cylinder according to claim 4, wherein a position detecting sensor is mounted on a side surface of the cylinder tube, and a driving body for driving the position detecting sensor is provided at an end of the slide table. A rodless cylinder, which is disposed so as to face the cylinder. 6. The rodless cylinder according to claim 1, wherein the first holding mechanism and the second holding mechanism have a wear resistance in which the sliding surface extending in the longitudinal direction of the cylinder tube is in sliding contact with the sliding surface. A rodless cylinder characterized by comprising a part. 7. The rodless cylinder according to claim 6, wherein at least a sliding surface and a wear-resistant portion constituting the second holding mechanism are provided on both sides of a bore defined in the cylinder tube, and are provided with a slide. A rodless cylinder, which is disposed so as to engage with each other outward of the bore when a load acts on the table. 8. The rodless cylinder according to claim 6, wherein at least one of the sliding surfaces or the wear-resistant portions is configured to be position-adjustable with respect to the wear-resistant portions or the sliding surfaces in sliding contact therewith. A rodless cylinder. 9. The rodless cylinder according to claim 6, wherein a swing member is provided on the slide table, a sliding surface is provided at one end of the swing member, and the other end of the swing member is provided. A rodless cylinder characterized in that a pressing screw is engaged with the cylinder. 10. The rodless cylinder according to claim 1, wherein the first and second holding mechanisms have a rolling portion corresponding to a portion supporting a load acting on the slide table and a rolling portion corresponding to other portions. A rodless cylinder characterized by selectively providing sliding portions.