JPH0728404Y2 - Cushion packing for pressure cylinder - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement of a cushion packing used for a pressure cylinder such as an air cylinder or a hydraulic cylinder.

Technical Background of the Invention and Problems Thereof For example, as shown in FIG. 6, a cylindrical casing 3 and a rod cover 8 and a head cover 10 for sealing both ends of the casing 3 (both of them are referred to as “end cover”). Also referred to as a), a piston rod 4 and a small-diameter end portion of the piston rod 4 along the axial direction of the casing 3 in a space surrounded by
The piston 14 is fitted so as to project concentrically on the 4a, and is fitted to the small-diameter end portions 4a of the piston rods on both sides of the piston 14 so as to sandwich the piston 14 so as to be in sliding contact with the casing inner peripheral surface. A piston that is reciprocally supported by the casing 3, the end covers 8 and 10, and the piston rod 4 as the cushion collars 20 and 20 as two sliding contact members reciprocate integrally. 14
Cushion chambers 18, 18 are formed on both sides of the piston 14 by and.

The cushion packing for the pressure cylinder performs a cushion action for smoothly reciprocating the piston rod 4 (and further the piston 14) in the pressure cylinder 2 as shown in FIG.

As shown in FIG. 6, the cushion packing 6 is mounted in recessed grooves 12, 12 formed on the inner peripheral surfaces of the rod cover 8 and the head cover 10, respectively.

The cushion packing 6 receives the fluid pressure from the fluid pressure introducing (discharging) ports 24 and 26 provided in the end covers 8 and 10, respectively, and is fitted to the small-diameter end 4a of the piston rod 4 as described above. Cushion color (sliding contact member) 20,20
The cushion chamber 18 is sealed by being brought into pressure contact with the surface thereof, and the pressure in the cushion chamber 18 is increased, thereby performing a cushioning action of reciprocating movement of the piston rod 4. In addition, in order to apply a reciprocating force to the piston rod 4 and the piston 14 as described above, the rod cover 8 and the head cover 10 are formed with ports 24 and 26 for introducing (discharging) fluid pressure. , These port 2
A fluid pressure is introduced into or extracted from the piston chamber 17 through 4, 26 so that a pressure difference is provided before and after the piston 14, and the piston 14 and the piston rod 4 connected thereto are axially reciprocated in the casing 3.

In addition, in FIG. 6, the piston 14 is moved to the left,
A cushion chamber 18 surrounded by the piston 14, the casing 3 and the head cover 10 is formed on the right side of the piston 14, but a similar cushion chamber is formed when the piston moves to the right side.

As shown in FIG. 7A, in the conventional cushion packing 6 that performs the reciprocating cushioning action on the piston rod 4 as described above, the cushion main body 6a mounted in the recessed groove 12 is inserted into the cushion chamber 18 An outer lip 28 and an inner lip 30 are provided so as to open toward the side, and an annular protrusion 32 is formed on the end surface of the packing body 6a on the side opposite to the cushion chamber (No. Sho 61-28086). See the bulletin).

When performing the cushioning action, the pressure from the cushion chamber 18 side pushes the packing body 6a to bring the annular protrusion 32 into contact with the end face 12a of the concave groove 12 on the side opposite to the cushion chamber and the inner lip 30.
Abut on the cushion collars 20 and 20, and
The pressure on the side is increased and the speed of the piston 14 is moderated.

Next, when the piston rod 4 moves to the left,
As shown in FIG. 7 (B), a fluid pressure (cracking pressure) is introduced from the port 26 to apply a leftward pressure to the piston 14. At this time, the packing body 6a may be
Move to the left in 12 and move to the inside lip 30 of the packing body 6a.
Comes into contact with the end wall on the cushion chamber side.

However, in this case, the tip end portion of the inner lip 30 may be pushed between the rod cover 8 and the cushion collar 20 to cause the cushion packing to be caught.

When such a phenomenon occurs, the fluid pressure (cracking pressure) is not introduced into the piston chamber 17 and cannot act on the piston 14, resulting in malfunction. The cracking pressure is the pressure introduced into the piston chamber when the piston 14 starts to move.

DISCLOSURE OF THE INVENTION The present invention has been made in order to eliminate such inconveniences associated with the prior art, and is for a pressure cylinder that does not cause the cushion packing biting phenomenon, and thus has excellent durability and smooth cushioning action. The purpose is to provide a cushion packing.

SUMMARY OF THE INVENTION To achieve the above object, a cushion packing for a pressure cylinder according to the present invention is provided in an end cover of a pressure cylinder having a substantially cylindrical casing and end covers sealing both ends of the casing. A packing that is mounted axially movably in a groove formed in the circumferential direction of the circumferential surface, and is a concentric circular protrusion formed on the outer circumferential surface of the piston rod that reciprocates in the axial direction in the casing. Pressure to perform a cushioning action by sealing each cushion chamber formed on both sides of the piston, which is formed by partitioning with the casing, the end cover, and the piston reciprocatingly supported by the piston rod and slidingly contacting the surface of the contact member. In a cylinder cushion packing, a packing body mounted in the groove and a projection on the packing body side of the packing body sandwiching the recess. Between the outer lip and the inner lip, an outer lip and an inner lip that are provided, an annular protrusion formed on the end surface of the packing body opposite to the cushion chamber, and a portion of the outer lip that is cut away. And a communication passage that communicates the outer peripheral space of the packing body with each other, and the outer lip and the inner lip are connected by a reinforcing rib.

According to the cushion packing according to the present invention,
When the cracking pressure acts, the cushion packing moves to one side inside the concave groove, but this fluid pressure passes around the cushion packing and enters the recess formed between the outer lip and the inner lip. Reach Since the outer lip and the inner lip are connected by the reinforcing ribs, the both lips are integrated, deformation of the inner lip is prevented, and the biting phenomenon of the cushion packing is prevented. . Therefore, the fluid pressure flows into the cushion chamber through the gap between the sliding contact member and the end cover, and the piston operates smoothly.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a sectional view of a main part showing a cushion packing according to an embodiment of the present invention, FIG. 2 is a front view of the same embodiment, and FIGS. 3 and 4 are lines III-III, IV-IV in FIG. FIG. 5 is a sectional view taken along with FIG. 5, which is an explanatory view of the operating state of the embodiment described above.

As shown in FIG. 1, a cushion packing P according to an embodiment of the present invention has a circumferential groove 12 formed in a rod cover 8 or a head cover 10 of a pressure cylinder 2 as shown in FIG. It is mounted inside so that it can move axially. In the present embodiment, the concave groove 12 is formed at the inner peripheral side end portion of the head cover 10 (or the rod cover 8).

The cushion packing P according to the present embodiment has a packing main body 6a having a substantially rectangular cross section, and an annular projection 50 extending continuously in the circumferential direction is provided on the end surface of the packing main body 6a on the side opposite to the cushion chamber. The annular projection 50 is formed integrally with the main body 6a, and abuts against the end surface 12a of the recessed groove 12 opposite to the cushion chamber to perform a sealing action. Also, on the end surface of the packing body 6a on the cushion chamber side,
An outer lip 51 and an inner lip 52 projectingly provided so as to open toward the cushion chamber side from 6a are integrally formed with the packing main body 6a with a recess 53 interposed therebetween.

A part of the outer lip 51 is cut out to form a communication passage 54 that connects the recess 53 formed between the outer lip 51 and the inner lip 52 and the packing body outer peripheral space,
Further, since the chamfered portion 12c is formed on the inner diameter side portion of the cushion chamber side end surface 12b of the concave groove 12, a fluid passage is formed around the cushion packing P.

There should be a gap between the outer peripheral surface of the packing body 6a and the groove 12.
Although 55 is formed and the fluid can flow in the axial direction therethrough, a groove for an outer peripheral surface flow passage that allows the fluid to flow in the axial direction may be formed on the outer peripheral surface of the packing body 6a.

Particularly, in this embodiment, the outer lip 51 and the inner lip 52 are
The ribs 51 and 52 are partially integrated with each other by connecting them with a reinforcing rib 56, which prevents the inner lip 52 from being deformed and prevents the above-mentioned trapping phenomenon of the cushion packing. . Moreover, if you do this,
Since it is not necessary to bury a reinforcing metal ring or the like inside the main body 6a of the cushion packing P, the manufacturing process of the cushion packing P is easy and the manufacturing cost does not increase. It should be noted that such a reinforcing rib 56 is also formed integrally with the packing body 6a. Next, the operation will be described.

As shown in FIG. 1, when a fluid pressure is applied from the cushion chamber 18 side, this fluid pressure enters through the gap between the rod cover 8 and the cushion collar 20 and is pushed to the right with the cushion packing P. But in this case, some of the fluid pressure is
Since it flows through the gap between the cushion packing P and the inner peripheral surface of the recessed groove 12, a large load does not act on the cushion packing P at the start of sealing, and the cushion packing can be prevented from turning over. .

When this fluid pressure pushes the cushion packing P further to the right, the annular protrusion 50 abuts on the end surface 12a of the rod cover 8 on the side opposite to the cushion chamber, and both lips 51, 52 are expanded to open the cushion chamber 18. Make a seal. As a result, a cushioning action is performed to prevent the piston 14 from suddenly colliding with the rod cover 8.

On the other hand, as shown in FIG. 5, when fluid pressure (cracking pressure) acts from the side opposite to the cushion chamber, this fluid pressure enters through the gap between the rod cover 8 and the piston rod 4, and the cushion packing P is left. Push outwards, outward lip
51 and the inner lip 52 are brought into contact with the cushion chamber side end surface 12b of the concave groove 12. In this case, since the outer lip 51 and the inner lip 52 are prevented from being deformed by the reinforcing ribs 56, the cushion packing P, particularly the inner lip 52, does not contact the rod cover 8 even if pressure is applied by fluid pressure. The phenomenon of being caught in the gap between the cushion collar 20 and the cushion collar 20 is prevented.

Further, in this embodiment, since the communication path 54 is formed in the outer lip 51 and the chamfered portion 12c is formed in the inner diameter side portion of the cushion chamber side end surface 12b of the recessed groove 12, the periphery of the cushion packing P is formed. A fluid passage will be formed in this. That is, the fluid pressure passes around the cushion packing P, between the communication passage 54 formed in the outer lip 51, the recess 53, the tip of the inner lip 52 and the chamfered portion 12c, and the rod cover 8.
Through the gap between the cushion collar 20 and the cushion collar 20 to reach the cushion chamber 18. Therefore, when the fluid pressure (cracking pressure) flows into the cushion chamber 18, the piston 14 starts to move smoothly.

Further, a large load does not act on the cushion packing P at the start of the sealing, so that the cushion packing can be prevented from being turned over, and the cushion function becomes smooth.

It should be noted that the present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the present invention. For example, the sliding contact member may be not only the cushion collar 20 formed separately from the piston rod 4 but also the integrally formed piston rod 4 itself, and the sliding contact with the cushion packing P is possible. Any contact member may be used.

Effects of the Invention As described above, according to the present invention, since the outer lip and the inner lip are connected by the reinforcing ribs, the both lips are integrated, the inner lip is prevented from being deformed, and the cushion packing The biting phenomenon is prevented, and as a result, the cracking pressure flows into the cushion chamber through the gap between the sliding contact member and the end cover, and the piston operates smoothly. In addition, the packing is not cracked or turned over, and the durability is greatly improved, and the cushioning effect is smooth.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part showing a cushion packing according to an embodiment of the present invention, FIG. 2 is a front view of the same embodiment, and FIGS. 3 and 4 are lines III-III, IV-IV in FIG. 5 is a sectional view taken along the line of FIG. 5, FIG. 5 is an explanatory view of an operating state of the embodiment, FIG. 6 is a sectional view of an essential part showing a conventional cushion packing, and FIGS. It is a figure. 2 ... Pressure cylinder member, 6a ... Packing body, 8, 10 ...
… End cover, 12 …… Concave groove, 12a, 12b …… End surface, 12c ……
Chamfer, 18 …… Cushion chamber, 20 …… Sliding contact member, 50 ……
Annular protrusion, 51 …… outer lip, 52 …… inner lip, 53…
… Recesses, 54 …… Communications, 56 …… Reinforcing ribs.

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. A pressure cylinder comprising a substantially cylindrical casing and end covers for sealing both ends of the casing, wherein an axial direction is provided in a groove formed in the circumferential direction of the inner peripheral surface of the end cover. A packing that is movably mounted, and appropriately slidably contacts a sliding contact member surface that is concentrically formed on the outer peripheral surface of a piston rod that reciprocates in the axial direction in the casing, and the casing and the end cover. A pressure cylinder cushion packing for partitioning and forming a cushion chamber formed on both sides of the piston, which is defined by a piston supported by the piston rod and reciprocating, and a packing body mounted in the groove. And an outer lip and an inner lip projecting on the cushion chamber side of the packing main body with a recess in between, and an anti-cushion chamber side of the packing main body. A ring-shaped projection formed on the surface, and a communication passage communicating between the recess formed between the outer lip and the inner lip and the packing body outer peripheral space by cutting out a part of the outer lip. A cushion packing for a pressure cylinder, wherein a reinforcing rib connects the outer lip and the inner lip. 2. The chamfered portion 12c is formed in the concave groove on the inner diameter side of the cushion chamber side end face 12b, and the pressure cylinder cushion packing according to claim 1 is mounted in the concave groove. Pressure cylinder.