JPH112208A - Rodless cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform optimum design such that a slit is closed to reduce leakage of fluid, and the seal function of a slit part is easily studied. SOLUTION: The inner surfaces 10 on both sides in the direction of width of a cylinder hole 3 are formed in an arcuate surface and an inner surface 7 on the slit side continued thereto is formed in a flat surface. The edge part 26c of an inner seal band 25 is brought into pressure contact with the inner surfaces 10 on both sides in the direction of width, and a movement amount L is set to a proper movement amount. Study of a seal function is facilitated in a way that the movement amount L and the diameters R of the inner surfaces 10 on the both sides in the direction of width are made constant regardless of the shape of a cylinder hole, and optimum design is practicable. Further, a piston packing having a protrusion entering a dent 34 formed by using the inner seal band 25 and the inner surfaces 10 on both sides in the direction of width is fitted in the two ends of a piston slidably fitted in the cylinder hole 3. Leakage of fluid is prevented by the piston packing and the inner seal band 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for taking out the movement of a piston in a non-circular cylinder hole in which the curvature of the inner surface on the slit side is zero or extremely small, to the outside of the tube. The present invention relates to a fluid-operated rodless cylinder having an outer portion in the axial direction of a packing sealed with a thin flat inner seal band.

[0002]

2. Description of the Related Art As a slit tube type rodless cylinder having a non-circular cylinder hole such as an ellipse or an ellipse, an inner surface provided with a cylinder hole has a flat flat surface, and a thin flat metal strip is formed on the flat surface. (See Japanese Patent Application Laid-Open No. 50-97775).
issue). Further, fitting grooves for an elastic sealing material are provided on both sides of the longitudinal slit of the cylinder tube having a non-circular cylinder hole, and a relatively thick elastic sealing material is fitted into the fitting groove to close the slit. Kaihei 1-1
No. 04407 and No. 6-40324.
Although not a flat type cylinder, on both sides of the longitudinal slit of a cylinder tube having a circular cylinder hole,
An arc surface is formed with an arc smaller than the arc radius that forms the inner surface of the cylinder hole, and a thin seal band that is curved upward in an arc shape when the slit is turned upward is brought into contact with the arc surface to form the slit. Obstruction (Japanese Unexamined Patent Publication No. Sho 62
-46009), a flat inner seal band is bent upward on the inner surface on both sides of the slit of the cylinder tube having the circular cylinder hole by the internal pressure from the inside of the piston hole,
Utilizing the pressing force of the seal band itself in the direction of the inner surface due to the curvature, the edge portion in the width direction of the inner seal band is pressed against the inner surface to seal (Japanese Patent Publication No. Sho 61-5006).
No.) is also known.

[0003]

In the prior art, a flat metal strip is pressed against the flat inner surface of the cylinder hole on both sides of the slit without moving in the pressing direction. ) Greatly affects the sealing performance of both, and unless the flatness is maintained with high accuracy, the sealing performance cannot be stably increased. In this case, since the elastic sealing material is extremely thick compared to a thin sealing band typified by a steel band, the wall thickness of the slit forming wall of the cylinder tube is usually thick, and as a result, the non-circular cylinder Even if the cylinder tube of the rodless cylinder has a flat outer shape by adopting the hole, there is a problem that the height (thickness) is not so thin as compared with the slit type rodless cylinder employing the circular cylinder hole. . Furthermore, in the point that the cylinder hole is circular, the structure of the rodless cylinder differs from the present invention,
Since it is not a so-called flat type rodless cylinder, the height of the rodless cylinder increases.
In addition to the disadvantages of such an overall configuration, the thin seal band is curved upward when the slit is turned upward, and inside the piston, the seal band is held down from above by a roller in a direction to eliminate the curvature. As a result, the seal band is forcibly deformed and used, and as a result, the durability of the seal band is reduced. In addition, since the seal band that is curved in an arc is pressed against the arc surface, the sealing property cannot be effectively exhibited unless the two arc surfaces are in good agreement. Furthermore, since the seal band has a curved arc surface, it is difficult to predict the deformation of the seal band due to internal pressure, and it is extremely difficult to consider the seal function. I have a problem.

Further, when the seal band is bent by the internal pressure along the inner surface of the arc, an elastic force is applied to the edge in the width direction to return the bending, and the force presses the edge against the inner surface. The edge portion of the seal band is pressed against the inner surface by the pressing force to seal between the inner surface and the inner surface in a state like a line contact. Therefore, when examining the sealing function, the amount of deflection of the seal band is an extremely important factor, and the sealing function is deteriorated even if the amount of upward bending of the seal band is too small or too large. Because the amount of movement (the amount of deflection) when the internal pressure is applied to the inner seal band is set to an appropriate value, the seal is sealed at the edge of the seal band. However, since the cylinder hole is circular, the inner surface radius of the seal band changes for rodless cylinders with different cylinder hole diameters. There has been a problem that the amount of bending must be considered and the design takes time. The problem of the present invention is that the curvature of the inner surface of the slit side is zero or extremely small, and the slit of the rodless cylinder of the non-circular cylinder hole which is extremely small is closed with less fluid leakage, and the sealing function of the slit portion can be easily studied. It is an object of the present invention to obtain a slit sealing device which is a rodless cylinder which can be designed optimally and which is much thinner than a conventional flat cylinder. Also,
Another object of the present invention is to provide a slit sealing device that can be easily designed even when flat cylinders having different cylinder hole shapes are manufactured.

[0005]

In order to solve the above-mentioned problems, the movement of the piston in the non-circular cylinder hole inside the tube is taken out of the tube through a longitudinal slit provided in the cylinder tube. The slit is a fluid-pressure operated rodless cylinder in which the outer portion in the axial direction from the piston packing at both ends of the piston is closed with a thin flat inner seal band, and the non-circular cylinder hole has a slit-side inner surface having a curvature on the slit side. In a rodless cylinder that is zero or extremely small, the inner surfaces of both sides in the width direction of the slit are formed with a curvature larger than the curvature of the inner surface of the slit side, and are used as the surfaces that the ends in the width direction of the inner seal band contact. Claim 1). Alternatively, through a longitudinal slit provided in the cylinder tube, the movement of the piston in the non-circular cylinder hole inside the tube is taken out of the tube, and the slit is formed in an axially outer portion than the piston packing at both ends of the piston. A non-circular cylinder hole, wherein the curvature of the inner surface on the slit side is zero or extremely small, wherein the non-circular cylinder hole is closed by a thin flat inner seal band. A recess is formed on both sides in the width direction to connect the slit side inner surface and the slit, and the recess inner surface is a surface with which the width direction end of the inner seal band is in contact, and the recess is flat in the width direction of the inner seal band. Depth at which the inner surface of the cylinder hole of the inner seal band is almost flush with the inner surface of the slit side when the ends are in contact Wherein there (claim 4). Specifically, the distance between the outer surface of the inner seal band and the inner opening of the slit in a state where both ends of the inner surface on both sides in the width direction are in contact with each other is set to an appropriate movement amount that minimizes fluid leakage from the slit. Item 2).

According to this, when an internal pressure is applied, the inner seal band can be bent in the slit direction to seal at the widthwise end, and compared to the case where the inner seal band is pressed against a flat surface, the inner seal band on both sides in the width direction can be formed. Even if the surface roughness in the axial direction is not maintained as precisely as the surface roughness in the direction along the arc of the inner surface on both sides in the width direction, a high sealing function can be exhibited, and the molding of cylinder tubes with non-circular cylinder holes is easy. Become. In addition, since the flat inner seal band is bent, the amount of bending and thereby the elastic force generated at the end in the width direction of the inner seal band can be easily studied, and the study of the sealing function can be easily performed. Furthermore, when the non-circular cylinder hole has a flat shape, the inner seal band is thin, so that the thickness of the slit forming wall of the cylinder tube can be reduced as compared with the conventional case using a thick resin band, The overall thickness of the rodless cylinder is reduced.

By making the curvature and the appropriate amount of movement constant regardless of the shape (including the size) of the non-circular cylinder hole (claim 3), if the optimum design is made for one cylinder hole shape, the curvature The appropriate movement amount can be applied to the rodless cylinder having another non-circular cylinder hole without any change, and the design labor can be reduced.

Preferably, the inner seal band is a seal band which is attracted to the cylinder tube by a magnetic attraction force, wherein the inner seal band is a thin steel band having elasticity, and the inner surfaces at both ends thereof are directed in the edge direction. It is chamfered and the end thickness is 0.1 mm or less.
7). According to this, the durability of the inner seal band itself is much better than that of the resin or other material, and the sealing property at the edge portion can be maintained high for a long period of time.

The piston packing is provided with a projection on the outer lip which enters into a recess formed by both ends of the inner seal band and the surface, and a portion of the base of the packing on the back side of the outer lip corresponding to the projection has a thick portion. (Claim 8). According to this, when the fluid pressure is high, the opening due to the fluid pressure of the lip and the restoring elasticity of the thick portion, and also when the fluid pressure is low, due to the restoring elasticity of the thick portion,
Since the piston packing is pressed against the widthwise end of the inner seal band and the inner surfaces on both sides in the widthwise direction, the fluid pressure is low,
Irrespective of the high pressure, the part where the piston packing and the inner end of the inner seal band in the width direction and the inner surfaces on both sides in the width direction are reliably sealed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to FIGS. The cylinder tube (body) 2 of the rodless cylinder 1 is formed by extruding or drawing a non-magnetic material (for example, aluminum alloy) and has a non-circular (oblong) cylinder hole 3.
A slit 4 is formed over the entire length in the longitudinal direction. As viewed in cross section, the cylinder tube 2 has, in addition to the cylinder hole 3 and the slit 4, a mounting groove 5 for mounting an end member and a sensor mounting groove 6 on the outer surfaces of the left and right side walls in parallel with the cylinder hole 3. Is formed.

As shown in FIGS. 4 and 5, the cylinder hole 3 has flat surfaces on the slit-side inner surfaces 7, 7 and the slit-side inner surface 8, which faces the slit 4, and the slit-side inner surfaces 7, 7 and the slit. The opposing inner surface 8 is continued by arcuate (semicircular) inner surfaces 9, 9 on both sides of the slit 4, and the slit-side inner surfaces 7, 7 have an arc-shaped cross section on both sides in the width direction of the slit 4. Both widthwise inner surfaces 10, 10 at which both ends in the width direction of the seal band 25 are in contact, are continuously formed, and the band receiving recesses are formed by the inner surfaces 10, 10 in the widthwise direction. The centers of the arcs forming the surfaces of the inner surfaces 10 on both sides in the width direction are respectively located in planes including the left and right slit surfaces 4a, 4a constituting the slit 4. In addition, the slit-side inner surface 7 may be formed to have an extremely small curvature in addition to the flat surface, and the width-direction inner surfaces 10 and 10 may be formed with a curvature larger than the curvature of the slit-side inner surface 7.

Both longitudinal end portions of the cylinder tube 2 are closed by left and right end caps 11, 11 to form a cylinder chamber 13 between the left and right end caps 11, 11.
The left and right end caps are the same except that the left and right shapes are symmetrical.
1 will be described. In FIGS. 1 and 2,
The end cap 11 and the cylinder tube 2 are connected to the fitting shaft portion 14 of the end cap 11 by a cylinder gasket 15.
A self-tapping screw (for example, as defined in JIS (Japanese Industrial Standards) B-1122), which is inserted into the end of the cylinder hole 3 and is fastened by forming a female screw in the lower hole by screwing in the hole. The end cap 1 is screwed into the end of the mounting groove 5 for mounting the end member.
The first cylinder tube 2 is connected to the cylinder tube 2 while determining its position in the width direction. There are three connection points for the end cap 11 with respect to the fluid supply / discharge port (not shown) formed on the side surface of the end cap 11 with the tapping screw 16.

The cylinder chamber 13 is divided into front and rear cylinder chambers 13A and 13B by a piston 18 having piston ends 18b at both ends of a piston body 18a. The piston 18 is integrally formed with a piston yoke 19 penetrating the slit 4. The piston yoke 1
9 extends right and left outside the cylinder tube 2,
It is a piston mount 20. In the piston mount 20, a band passing space 21 through which the outer seal band 26 passes is closed by a cover member 22 made of a resin material.
A moving body 23 is constituted by the piston 18, the piston yoke 19, and the piston mount 20. The piston body 18a, the piston yoke 19, and the piston mount 20 are entirely formed of a single member made of an aluminum alloy. On the outer periphery of the lower end of the piston mount 20,
A scraper 24 is attached around the entire circumference to prevent dust from entering through a gap between the upper surface of the cylinder tube 2 (the outer surface on the slit opening direction side) and the lower surface of the piston mount 20.

The inner and outer seal bands 25 and 26 for closing the slit 4 from the inside and the outside pass through the upper and lower sides of the piston yoke 19, and both ends reach the left and right end caps 11 and 11, respectively. The inner and outer seal bands 25 and 26 are thin elastic bands having elasticity, and are made of a magnetic material such as a steel band. Inner / outer seal band 2
As is well known, 5 and 26 have a width larger than the width of the slit 4. Each of the seal bands 25, 26 has both ends thereof at the corresponding band fitting holes 2 of the end cap 11.
7 and 28, and the mounting pins 3 are inserted from outside with the mounting holes (not shown) provided at both longitudinal ends of the seal bands 25 and 26 and the pin holes 29 of the end cap 11 aligned.
0 is fitted into the pin hole 29 and connected to the end cap 11.

Magnets 31 for attracting the inner and outer seal bands 25 and 26 are arranged on both sides of the slit 4 on the outer surface of the cylinder tube 2 along the length thereof.
Except for the portion passing through the piston yoke 19, the inner seal band 25 closes the slit 4 from the inside by the magnetic attraction force and the fluid pressure applied to the cylinder chamber 13, and the outer seal band 26 has the magnetic attraction force. To close the slit 4 from the outside.

As shown in FIG. 5, the inner seal band 25 is chamfered at both ends in the width direction of an inner side surface 25a facing the cylinder hole 3 toward an edge portion 25c. The widthwise end of the side surface 25b is an edge portion 25c that presses against the inner surfaces 10, 10 on both sides in the width direction of the slit 4, and the edge portion 25c is not deformed in the longitudinal direction with high precision, for example, by shaper processing. , Is formed. A recess 34 is formed by both end portions of the inner seal band 25 and the inner surfaces 10 on both sides in the width direction. The thickness of the end of the inner seal band 25 is preferably 0.02 to 0.05 mm, and is formed to 0.1 mm or less. When the inner seal band 25 is flat, the inner side surface 25a is flush with the slit-side inner surfaces 7,7. Slit side surface 25 of inner seal band 25
The amount of movement L, which is the distance between b and the inner opening of the slit 4, is set to an appropriate amount of movement that reduces the fluid leakage from the slit to such a degree that there is no practical problem. This appropriate movement amount is determined by experiments or the like.

Thus, for one cylinder hole shape in which the inner surface 7 on the slit side is flat or the curvature is set to be extremely small, the predetermined inner surfaces 1 on both sides in the axial direction can reduce the amount of leakage.
When the curvature of 0 and 10 and one appropriate movement amount are determined, the same value of the curvature and the appropriate movement amount is applied, and another cylinder in which the slit-side inner surface 7 is flat or whose curvature is set to be extremely small is determined. Needless to say, even when applied to a hole-shaped one, the sealing function is satisfied.
The inner radius R and the amount of movement L on both sides in the width direction corresponding to different cylinder hole shapes with different pressure receiving areas that produce different cylinder outputs.
It is not necessary to set a new value, and the optimum design of the sealing performance of the slit portion can be easily performed. By the way, the radius R is 2
When the amount of movement was 5 mm and the amount of movement L was 0.125 mm, the amount of leakage of the pressurized fluid from the slit 4 was small and practical.
In the first aspect of the present invention, it is not denied that the width-direction inner surface radius R and the movement amount L are not made the same and are examined each time.

The piston ends 1 at both ends of the piston 18
8b is provided with a fitting groove 36 into which the piston packing 35 is fitted. The piston packing 3 is inserted into the fitting groove 36.
5 are fitted. The piston packing 35 is in the cylinder hole 3
It has a larger similar shape. Piston packing 35
As shown in FIGS. 6 and 7, U has a substantially U-shaped cross-section formed of a base 37, an inner lip 38, and an outer lip 39, and having a gap 40 between the inner lip 38 and the outer lip 39. Packing. Inner lip 38 and base 37
The outer lip 39 presses the inner surface of the cylinder hole 4 and the inner seal band 25 from the inside in a state where the piston 18 is fitted in the cylinder hole 4. As shown in FIGS. 6 and 7, on the outer lip 39 on the inner seal band 25 side, a projection 41 a having a shape corresponding to the recess 34 between both ends in the width direction of the inner seal band 25 and both inner surfaces 10 in the width direction is provided. Is provided. The base 37 has a portion on the back side of the outer lip 39 on which the protrusion 41a is formed, which is formed in a thick portion 41b as compared with the other thickness of the base 37, and is continuous with the protrusion 41a. The thick portion 41b
From the connection point A of the inner lip 38 and the outer lip 39
Piston packing 2 on the opposite side of the lip opening direction
5 is compressed when it is inserted into the piston hole 3,
The seal between the inner surface 10 in the width direction and the inner seal band 25 is pressed against the inner surface 10 in the width direction by the restoring elasticity due to the compression stiffness greater than the compression stiffness of the other base portions not b.

The piston packing 35 is formed of rubber and has a rubber hardness (HS70) of a general piston packing.
However, the surface of the piston packing 35 may be subjected to a chemical conversion treatment (for example, chlorination treatment) to improve durability and lubricity, or the rubber hardness (HS70) may be used to improve sealing performance. Rubber hardness (H)
(About S60), and the surface of the piston packing 35 may be subjected to the above-described chemical conversion treatment in order to compensate for the reduced durability.

Reference numeral 42 denotes an external damper, which is attached to the end cap 11 on the side facing the piston mount 20 and abuts against the piston mount 20 at the stroke end of the piston mount 20 to absorb its kinetic energy.

The rodless cylinder 1 is an end cap 1
Pressure fluid from a supply / discharge port (not shown) provided on one side is supplied / discharged to the front and rear cylinder chambers 13A, 13B, whereby the piston 18, that is, the moving body 23 moves left and right. Hollow 34
The fluid pressure acts on the outer lip 39 at the protrusion 41 a of the piston packing 35 that has entered the outer lip 39, and the outer lip 39 is pressed outward and presses against the width-direction inner surfaces 10 and the inner seal band 25 from the inside. 8, the piston packing 35 extends from the connection point A between the outer lips 38 and 39 to the point B where the pressure contact between the thick portion 41b, the inner surface 10 on both sides in the width direction, and the inner seal band 25 starts.
The solid portion of the base 37 is formed on both sides in the width direction by the compression stiffness increased by providing the thick portion 41b.
0 and press against the inner seal band 25. In this manner, the gathered portion of the piston packing 35, the inner surfaces 10 on both sides in the width direction, and the end of the inner seal band 25 is sealed by pressing the outer lip 39 by the fluid pressure and restoring elasticity by the thick portion 41b. Of course, the outer lip 39 also presses against the inner periphery of the other cylinder hole 3 to seal the portion.

In a portion not corresponding to the piston packing 35, the inner seal band 2
5 protrudes toward the slit 4, and the edge portion 25 c due to the bending of the inner seal band 25 is pressed against the inner surface 10 on both sides in the width direction and the pressure of the pressurized fluid. When the piston 18 moves in this state by pressing against the inner surfaces 10 on both sides to prevent leakage of the pressurized fluid, the piston packing 35
, The inner seal band 25 and the piston packing 35 maintain the sealing property in the cylinder chamber 6. In the present configuration in which the sealing is performed at the edge portion 25c, even if the surface roughness in the axial direction of the inner surface 10 in the width direction is lower than the surface roughness in the direction along the arc of the inner surface 10 in the width direction, the sealing property can be maintained. , Thereby the flatness (two-dimensional direction)
The molding of the cylinder tube 2 can be easily performed as compared with the conventional one which requires the surface roughness of the cylinder tube 2 to be high precision.

When the pressure fluid acting on the front and rear cylinder chambers 13A and 13B is high, the pressure contact force of the outer lip 39 is proportional to the pressure.
Receives a strong pressing force in the direction of pressing against the inner surface of the cylinder hole 3, the inner surfaces 10 on both sides in the width direction, and the inner seal band 38, so that the sealing property is high in combination with the restoring elasticity of the thick portion 41 b.
Further, since the sealing property of the outer lip 39 is proportional to the pressure, when the pressure fluid is low pressure, the sealing property of the outer lip 39 is reduced, but the thick portion 41b is not affected by the pressure of the pressure fluid, Due to the squeeze effect due to the increase in the compression stiffness (the sealing effect due to the resilient elasticity generated by the compression of the thick portion 41b of the packing 35), the sealing performance is maintained because the thick portion 41b is strongly pressed against the gathering portion. . The thick portion 41b is provided only at a position corresponding to the protrusion 41a, and the outer lip 39 of the other portion has a gap 40 between the inner lip 38 and the outer lip 39.
As a result, the outer lip 39 can be deformed toward the center of the cylinder hole 3 and the restoring elasticity of the lip is small.
As compared with the pressing force of 1a, the sliding resistance of the entire piston 18 is small, and the piston 18 can be operated smoothly.

The shape of the cylinder hole 3 of the cylinder tube 2 may be as shown in FIGS. 10 to 12, wherein the slit-side inner surfaces 7, 7 are flat or have extremely small curvature, and The other inner surfaces may have any shape as long as the inner surfaces 10 on both sides are arc-shaped larger than the curvature of the inner surfaces 7, 7 on the slit side.

In another example of the present invention, as shown in FIG. 13, on both sides in the width direction of the slit 4, a small angle with respect to the slit-side inner surface 7, not the band-housing recess formed by the inner surface of the arc as described above. Planes 10A, 10 intersecting at
B, and a band accommodating depression in which the slit 4 and the slit-side inner surface 7 are continuous may be formed. 13, the inner surface 25 of the seal band 25 in a flat state is shown.
a forms the same plane as the flat slit-side inner surface 7, and
The distance between the outer surface 25b of the seal band and the inner opening of the slit is set to the appropriate amount of movement as described above. For this reason, the band accommodating recess is very shallow.

[0026]

As described above, according to the present invention, in a rodless cylinder having a non-circular cylinder hole in which the curvature of the inner surface on the slit side is zero or extremely small, the inner surfaces on both sides in the width direction of the slit are connected to the slit side. It is formed with a curvature larger than the curvature of the inner surface, and it is a surface where the width direction end of the inner seal band is in contact, or a band receiving recess which connects the slit side inner surface and the slit on both sides in the width direction of the slit is formed. The inner surface of the housing recess is a surface with which the width direction end of the inner seal band contacts, and the band housing recess is formed in the cylinder hole of the inner seal band in a state where the width direction end of the inner seal band is in a flat state. Since the side surface was set to a depth almost flush with the slit side inner surface,
When the internal pressure is applied, the inner seal band can be bent in the slit direction to seal at the width direction end, and the axial surface roughness of the width direction inner surface on both sides in comparison with the case of pressing in a plane, There is an advantage that a high sealing function can be exhibited and a cylinder tube having a non-circular cylinder hole can be easily formed without maintaining the surface roughness in a direction along the arc surface of the inner surface in the width direction on both sides with high accuracy. . In addition, since the flat inner seal band is bent, the amount of bending and thereby the elastic force generated at the width direction end of the inner seal band can be easily examined,
Examination of the sealing function is facilitated.

When the non-circular cylinder hole has a flat shape, the inner seal band is thin, so that the thickness of the slit forming wall of the cylinder tube is smaller than that of the conventional case using a thick resin band. The rodless cylinder can be made thinner.

In a rodless cylinder having a non-circular cylinder hole in which the curvature of the inner surface on the slit side is zero or extremely small, the curvature (radius) of the inner surface in one width direction on both sides in a certain cylinder hole shape. If the appropriate movement amount (bending amount) of the inner seal band corresponding to this is determined, those curvatures and bending amounts can be applied to another cylinder hole shape as it is, so that the same sealing effect can be obtained. Since it can be expected, the trouble of studying the amount of bending etc. corresponding to different cylinder hole shapes is reduced each time,
This has the effect of reducing man-hours required for design.

When the seal band is made of a steel band, the durability is remarkably higher than that of a resin band or other material, and the sealing property at the edge portion can be maintained high for a long period of time.

Further, a projection is provided at the tip of the lip which enters into the recess formed between both ends of the inner seal band and the surface, and a portion of the base of the packing corresponding to the projection is formed in a thick portion at the back side of the lip. With the piston packing described above, high sealing performance can be maintained over a wide range of fluid pressure from low pressure to high pressure due to the seal by the pressing action of the lip and the squeeze effect of the thick portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rodless cylinder embodying the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a diagram showing a cross-sectional shape of a cylinder tube.

FIG. 5 is an enlarged view of a portion V in FIG. 4;

FIG. 6 is a front view of the piston packing.

FIG. 7 is an enlarged cross-sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is an explanatory diagram showing a fitting state of the piston packing to the piston end.

FIG. 9 is an explanatory view showing a mounted state of a piston packing.

FIG. 10 is a sectional view showing another shape of a cylinder hole.

FIG. 11 is a sectional view showing another shape of a cylinder hole.

FIG. 12 is a sectional view showing another shape of a cylinder hole.

FIG. 13 is a view showing the shape of another band accommodation recess.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rodless cylinder 2 Cylinder tube 3 Cylinder hole 4 Slit 7 Inner surface on slit side 10 Inner surface on both sides in width direction 18 Piston 25 Inner seal band 25a Inner surface 25b Outer surface 34 Depression 35 Piston packing 39 Outer lip 41a Projection 41b Thick portion L Movement amount (Appropriate travel distance)

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[Procedure amendment]

[Submission date] May 15, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006] According to this, when an internal pressure is applied, the inner seal band can be bent in the slit direction to seal at the end in the width direction , which is higher than in a case where the inner seal band is pressed against a flat surface. The function can be exhibited, and the molding of a cylinder tube having a non-circular cylinder hole becomes easy. In addition, since the flat inner seal band is bent, the amount of bending and thereby the elastic force generated at the end in the width direction of the inner seal band can be easily studied, and the study of the sealing function can be easily performed. Furthermore, when the non-circular cylinder hole has a flat shape, the inner seal band is thin, so that the thickness of the slit forming wall of the cylinder tube can be reduced as compared with the conventional case using a thick resin band, The overall thickness of the rodless cylinder is reduced.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

In a portion not corresponding to the piston packing 35, the inner seal band 2
5 protrudes toward the slit 4, and the edge portion 25 c due to the bending of the inner seal band 25 is pressed against the inner surface 10 on both sides in the width direction and the pressure of the pressurized fluid. When the piston 18 moves in this state by pressing against the inner surfaces 10 on both sides to prevent leakage of the pressurized fluid, the piston packing 35
, The inner seal band 25 and the piston packing 35 maintain the sealing property in the cylinder chamber 6. In this configuration in which sealing is performed at the edge portion 25c , high sealing performance
Can be maintained, so that flatness (two-dimensional direction)
The molding of the cylinder tube 2 can be easily performed as compared with the conventional one which requires the surface roughness of the cylinder tube 2 to be high precision.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

[0026]

As described above, according to the present invention, in a rodless cylinder having a non-circular cylinder hole in which the curvature of the inner surface on the slit side is zero or extremely small, the inner surfaces on both sides in the width direction of the slit are connected to the slit side. It is formed with a curvature larger than the curvature of the inner surface, and it is a surface where the width direction end of the inner seal band is in contact, or a band receiving recess which connects the slit side inner surface and the slit on both sides in the width direction of the slit is formed. The inner surface of the housing recess is a surface with which the width direction end of the inner seal band contacts, and the band housing recess is formed in the cylinder hole of the inner seal band in a state where the width direction end of the inner seal band is in a flat state. Since the side surface was set to a depth almost flush with the slit side inner surface,
When an internal pressure is applied, the inner seal band can be bent in the slit direction to seal at the end in the width direction, so that a higher sealing function can be exhibited as compared with a case where the inner seal band is pressed against a flat surface . Also, since the flat inner seal band is bent, the amount of bending and
Thereby, the elastic force generated at the end in the width direction of the inner seal band can be easily studied, and the study of the sealing function can be easily performed.

Claims (8)

[Claims] 1. A movement of a piston in a non-circular cylinder hole inside a tube is taken out of the tube through a longitudinal slit provided in a cylinder tube, and the slit is more axially moved than a piston packing at both ends of the piston. A fluid-pressure operated rodless cylinder having an outer portion covered with a thin flat inner seal band, wherein the non-circular cylinder hole has a curvature of a slit side inner surface of zero or
In a rodless cylinder that is extremely small, the width-direction inner surfaces of both sides of the slit are formed with a curvature larger than the curvature of the slit-side inner surface, and the width-wise end of the inner seal band is a surface that contacts. Rodless cylinder. 2. The distance between the outer surface of the inner seal band and the inner opening of the slit in a state where both ends are in contact with the surface is set to an appropriate amount of movement to minimize fluid leakage from the slit. The rodless cylinder according to claim 1, wherein 3. The non-circular cylinder according to claim 2, wherein the curvature and the appropriate movement amount are constant irrespective of the shape of the non-circular cylinder hole.
The rodless cylinder described. 4. A movement of a piston in a non-circular cylinder hole inside the tube is taken out of the tube through a longitudinal slit provided in the cylinder tube, and the slit is more axially moved than a piston packing at both ends of the piston. A fluid-pressure operated rodless cylinder having an outer portion covered with a thin flat inner seal band, wherein the non-circular cylinder hole has a curvature of a slit side inner surface of zero or
In a rodless cylinder that has been made extremely small, a band housing recess is formed on both sides in the width direction of the slit, the band housing recess continuing the slit-side inner surface and the slit. In the state where the width direction end of the inner seal band in a flat state is in contact with the band receiving recess, the inner side surface of the cylinder hole of the inner seal band has a depth substantially flush with the inner surface of the slit side. Characterized rodless cylinder. 5. The distance between the outer surface of the inner seal band and the inner opening of the slit in a state where both ends are in contact with the surface is set to an appropriate amount of movement to minimize fluid leakage from the slit. The rodless cylinder according to claim 4, wherein 6. The rodless cylinder according to claim 1, wherein the inner seal band is a seal band that is attracted to the cylinder tube by magnetic attraction. 7. The rodless device according to claim 6, wherein the inner seal band is a thin steel band, and the inner surfaces at both ends are chamfered in the edge direction, and the thickness at the ends is 0.1 mm or less. Cylinder. 8. The piston packing is provided with a projection on the outer lip which enters into a recess formed by both ends of the inner seal band and the surface, and a portion of the base of the packing on the back side of the outer lip corresponding to the projection is thick. 8. The rodless cylinder according to claim 7, wherein the rodless cylinder is formed in a meat portion.