JPH0640324Y2 - Rotless dress cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention is a slit groove in which a connecting portion protruding from the outer periphery of a piston is formed in the cylinder by reciprocating the piston fitted in the cylinder with pressurized air. The present invention relates to a rodless cylinder adapted to reciprocate along the axis, and more particularly, to a rodless cylinder having an improved structure of a portion which seals around a piston with a seal ring.

Problems to be Solved by Conventional Techniques and Inventions In recent years, as an air cylinder that can reduce the mounting space in the length direction of the cylinder, instead of the conventional rod-type air cylinder, a cylinder whose both ends are sealed has an inner surface. To the outer surface of the slit groove over the entire length and both sides of the inner surface of the slit groove are trimmed to a certain depth over the entire length, and a seal band made of an elastic material that closes the slit groove is fitted to the side groove. The both ends of the piston, and then fix the both ends to the cylinder, and insert the seal band into the insertion passage that is transparently provided inside the piston fitted in the cylinder, and connect the protruding portion of the piston to the outside from the slit groove. By projecting and supplying air to the front chamber or rear chamber of the piston, the connecting portion is reciprocated along the slit groove while inserting the seal band into the insertion passage. The so-called rodless cylinder has come to be used.

In this rodless cylinder, it is difficult to accurately match the inner surface of the seal band with the inner surface of the cylinder, and the seal band slightly protrudes from the inner surface of the cylinder. At the edge, a gap is formed between the lip and the lip of the seal ring fitted around the piston, and pressurized air may leak to reduce the operating efficiency. This gap can be eliminated by increasing the pressing force of the lip of the seal ring and bringing both side edges of the seal band into close contact with the inner surface of the cylinder.However, if the pressing force of the lip is increased, sliding against the cylinder will occur. It has the disadvantage of increasing resistance and likewise decreasing operating efficiency.

Therefore, the applicant of the present application, in Japanese Patent Application No. 62-36083,
The pressing force of the lip of the seal ring made of an elastic material that seals the circumference of the piston by fitting it on the outer periphery of the piston and pressing the lip against the inner surface of the cylinder and the seal strip is applied to other parts. By making it larger than the part, the side edges of the seal band are crushed to eliminate the gap, and the sliding resistance of the piston as a whole is kept small so that the operating efficiency is not lowered. However, since the pressing force is increased only on the seal band side of the seal ring, the sliding resistance on the seal band side of the seal ring becomes relatively larger than that on the opposite side. The balance of sliding resistance over the entire circumference is lost, and the seal ring slides in a twisted state and rubs against the inner peripheral surface of the cylinder, causing uneven wear on the lip on the seal band side. There is a possibility that the leakage occurs in the period, it had been still left room for improvement.

Means for Solving the Problems The rodless cylinder of the present invention has been devised in view of such circumstances, and it is fitted to the outer circumference of the piston to press the lip against the inner surface of the cylinder and the seal band. The seal ring lip made of an elastic material that seals around the piston thereby presses the pressing force between the part that contacts both side edges of the seal band and the part that is symmetrical on the opposite side of the seal band from the other part. It has a larger structure.

The operation and effect of the present invention With the above-mentioned structure, since the pressing force of the portion of the lip of the seal ring which contacts both side edges of the seal band is large, both side edges of the seal band are protruded when the seal band projects to the inner surface of the cylinder. Is squeezed, and both side edges of the seal band and the part where the cylinder and the lip gather are in close contact with each other with no gap, and the front chamber and the rear chamber are not only kept airtight, but the opposite of the seal band side. Since the pressing force of the lip located at the symmetrical position to the above is also increased, the seal ring receives the same sliding resistance on the seal band side and the opposite side, and the sliding resistance is balanced over the entire circumference. The seal ring is prevented from sliding without twisting and uneven wear of the lip is prevented, and it is possible to perform an airtight function for a long period of time, and most of the other parts of the lip contact the inner circumference of the cylinder. In this case, since the pressing force is small, the sliding resistance of the piston as a whole can be suppressed to a small value, and there is an effect that there is almost no risk of a decrease in operating efficiency.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

The rodless cylinder of this embodiment is divided by a piston 5 in a cylinder 2 in which a slit 3 which extends from the hollow 3 whose both ends are closed to reach the outer surface is formed over the entire length and an elongated piston 5 is fitted in the hollow 3. The front chamber 6 and the rear chamber 7 are
By alternately supplying and exhausting air from the ports 8 and 8, the connecting portion 9 with the piston 5 protruding from the upper portion thereof is formed.
Reciprocating in a state of penetrating into the slit groove 4, the table 10 attached to the upper end of the connecting portion 9 is linearly reciprocally driven along the slit groove 4, and at the same time, both ends of the cylinder 2 A rubber seal band 15 for closing the slit groove 4 fitted to the side grooves 11, 11 formed by cutting off both sides of the inner surface of the slit groove 4 to a fixed depth on the upper surface of both ends of the piston 5. It is adapted to be inserted through an insertion passage 16 formed so as to come into contact with and penetrate into the center thereof. The circumferential fitting grooves 17 and 17 formed on the outer circumferences of both ends of the piston 5 respectively,
A rubber seal seal 20 is fitted to the inner peripheral surface of the cylinder 2 and the lower surface of the seal band 15 to keep the front chamber 6 and the rear chamber 7 airtight.

The seal ring 20 has a base portion that is in close contact with the bottom surface of the fitting groove 17.
Corresponding lips 22 are formed on the outer peripheral side of the gap 21 with gaps 23, and as shown in FIGS. 2 and 3, the lips 22 are formed at the portions corresponding to both side edges of the seal band 15. Base 21
By forming the solid portions 24a, 24a filling the gap 23 with the strong pressure portions 25a, 25a, the above-mentioned seal band
Similarly, the gap 23 between the lip 22 and the base 21 is formed in the solid portions 24b and 24b at the portions corresponding to both side edges of the seal ring 15 and at the symmetrical positions with respect to the horizontal center line of the seal ring 20. The strong pressure portions 25b, 25b are formed by filling the ridge 22 with the lips 22 by being crushed slightly in the radial direction over the entire circumference between the inner peripheral surface of the cylinder 2 and the bottom surface of the fitting groove 17. The base 21 is fitted in a deformed state so as to approach the base 21.

In the strong pressure portions 25a, 25a corresponding to both side edges of the seal band 15 of the seal ring 20, since the gap 23 is filled with the solid portions 24a, 24a, the compression stiffness is large and the resilience of the lip 22 is large. Is strong, and both side edges of the seal band 15 projecting in a stepped manner on the inner surface side of the cylinder 2 are crushed by the lip 22 so that the cylinder 2 is smoothly connected, and a gap is formed between the connection portion and the lip 22. The airtightness is maintained and
Further, since the strong pressure portions 25b and 25b are similarly formed at positions vertically symmetrical to the above-mentioned strong pressure portions 25a and 25a to strongly press the inner peripheral surface of the cylinder 2, the seal ring 20 is well balanced on both the upper and lower sides. By receiving the same sliding resistance, it is possible to prevent the seal ring 20 from sliding without twisting and uneven wear of the lip 22, and in most other cases where the gap 23 is left, the gap 23 Since the lip is narrowed and easily deformed, the resilience of the lip 22 is small, and the pressing force against the inner peripheral surface of the cylinder 2 and the lower surface of the seal band 15 is weak, so that the sliding resistance is small and the seal ring 20 as a whole is small. Since the sliding resistance of the cylinder 2 is kept small and the gap 23 remains, the inner peripheral surface of the cylinder 2 and the lower surface of the seal band 15 are smooth even if the pressing force of the lip 22 is weak, so that airtightness is maintained. , All around the seal ring 20 Connexion airtight is maintained.

Further, since the seal ring 20 has a vertically symmetrical shape, it is not necessary to pay attention to the vertical direction when fitting it into the fitting groove 17 of the piston 5, and the assembly can be carried out efficiently.

FIG. 4 shows another embodiment, in which the bottoms of the fitting grooves 37 formed at both ends of the piston 5a are the portions 34a, 34a corresponding to both side edges of the seal band 15 and the portions which are vertically symmetrical to the portions 34a, 34a. 34
b and 34b are raised and the depth thereof is shallower than other portions, and a seal ring formed in this fitting groove 37 by forming a gap 33 between the lip 32 and the base 31 over the entire circumference. 30 is crushed and fitted in the radial direction, and the portion corresponding to the shallow portions 34a and 34b of the fitting groove 37 of the seal ring 30 has a larger restoring amount because the crushed amount is larger than the other portions. Strong pressure portions 35a and 35b are formed, and the upper pressure portion 35a strongly presses both side edges of the seal belt 15 to
The gap between the connection portion of 5 and the cylinder 2 and the lip 32 is eliminated, and the upper strong pressure portion 35b balances the upper and lower sliding resistances so that the seal ring 30 can slide without twisting. .

[Brief description of drawings]

1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is an end view of the AA line of FIG. 1, FIG. 3 is a partially cutaway perspective view of a seal ring, and FIG. 4 is another embodiment. FIG. 3 is an end view corresponding to FIG. 2 above, according to an example. 2: Cylinder, 4: Cut groove, 5, 5a: Piston, 6: Front chamber,
7: rear chamber, 9: connecting part, 11: side groove, 15: seal band, 16: insertion passage, 17, 37: fitting groove, 20, 30: seal ring, 22, 32: lip, 25a, 25b, 35a , 35b: High pressure part

Front Page Continuation (72) Yoshio Shido, Yoshio Shidou, 3005 Hayasaki, Kita Sotoyama, Komaki City, Aichi Prefecture, KK Day Co., Ltd. ) References JP-A-56-124711 (JP, A) JP-A-62-184208 (JP, A) Actual break-in 63-142404 (JP, U)

Claims (3)

[Scope of utility model registration request] Claims: 1. A slit groove is formed on the inner surface of a cylinder whose both ends are hermetically closed, opening to the outer surface over the entire length, and both sides of the inner surface of the slit groove are formed on the inner groove by shaving a fixed depth over the entire length. While fitting a seal band made of an elastic material that closes the slit groove to fix both ends of the seal band to the cylinder,
The seal band is inserted into an insertion passage transparently provided inside the piston fitted in the cylinder, and a connecting portion protruding from the piston is projected outside from the slit groove to form a front chamber or a rear chamber of the piston. In the rodless cylinder in which the connecting portion is reciprocally moved along the slit while inserting the seal band into the insertion passage by supplying air to the piston, the rod is fitted to the outer periphery of the piston. A portion of the lip of the seal ring made of an elastic material that seals around the piston by pressing the lip against the inner surfaces of the cylinder and the seal band, and a portion of the lip that contacts both side edges of the seal band, and the seal band of the portion. A rodtless cylinder characterized in that the pressing force with a symmetrical portion on the opposite side is made larger than that of the other portion. 2. The rodless cylinder according to claim 1, wherein the compression stiffness of the seal ring is partially increased. 3. The rodless cylinder according to claim 1, wherein the depth of the fitting groove of the seal ring provided around the piston is partially reduced.