JPH0614631U - Packing - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a packing that can satisfactorily seal even a housing having a large variation in inner diameter. [Structure] The shaft 6 is inserted into the housing 8. The ring-shaped packing 1 made of a rubber-like elastic body is mounted in the packing mounting groove 7 of the shaft 6. The packing 1 has a fixed lip 5 and a seal lip 4 formed in an annular shape on one end surface thereof. The seal lip 4 includes a first lip portion 2 and a second lip portion 2 having different diameters.
And a lip portion 3. When the inner peripheral surface of the housing 8 is located above a, the first lip portion 2 abuts on the housing 8 and seals. When the inner peripheral surface of the housing 8 is located on the position b, the first lip portion 2 undulates, but the second lip portion 3 abuts the housing 8 favorably, so that the sealing performance is secured. Therefore, even if there is a large variation in the inner diameter of the housing 8, it is possible to deal with this with only one packing 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a packing, and more particularly to a packing that is provided between two members that can move relative to each other so as to seal the two members.

[0002]

[Prior art and its problems]

 Conventionally, as this type, as shown in FIG. 3, for example, a packing has been already known which is provided between a shaft 26 and a housing 28, which are capable of relative movement, to seal between both members.

That is, the packing 21 shown in FIG. 3 is a so-called U-ring, and a fixing lip 25 that can abut the shaft 26 and a housing 28 are provided on one end surface of an annular rubber-like elastic body. Since the seal lips 24 capable of contacting with each other are formed in an annular shape, by mounting the packing 21 in the packing mounting groove 27 of the shaft 26, the packing 21 is provided between the shaft 26 and the housing 28. An intervening member is provided to seal between the two members.

In FIG. 3, a housing 28 is inserted into the housing 28 with the shaft 26 being slightly separated, and supports the shaft 26 in a rotatable and reciprocating state.

The shaft 26 inserted into the housing 28 is formed with an annular packing mounting groove 27 that opens to the outer peripheral surface thereof, and the packing 21 is mounted inside the packing mounting groove 27. There is.

The packing 21 is a so-called U-ring, which is made of a rubber-like elastic body having a good sealing property and is formed in an annular shape as a whole. A fixing lip 25 is formed on the inner peripheral side of one end surface of the packing 21. However, the seal lips 24 are formed annularly on the outer peripheral side.

Then, the packing 21 is mounted in the packing mounting groove 27 of the shaft 26, and the shaft 26 mounted with the packing 21 is inserted into the housing 28 so that the outer peripheral portion of the packing 21 is the inner peripheral surface of the housing 28. The packing 21 is arranged so that the inner surface of the packing 21 abuts on the outer surface of the shaft 26.

By mounting the packing 21 in the packing mounting groove 27 formed in the shaft 26 as in the above-described configuration, the packing 21 is interposed between the shaft 26 and the housing 28. A packing 21 seals between the shaft 26 and the housing 28 in a relatively movable state.

First, when the packing 21 is mounted in the packing mounting groove 27 of the shaft 26, the fixing lip 25 of the packing 21 fixes the packing 21 in the packing mounting groove 27 by tightening the shaft 26 by its elastic force. At the same time, a sealing property can be obtained on the contact surface with respect to the shaft 26.

On the other hand, the seal lip 24 of the packing 21 slidably abuts on the inner peripheral surface of the housing 28 by its elastic force, so that the abutment surface has a sealing property. Therefore, as a result, the packing 21 seals between both members.

Here, when pressure is introduced into the packing attachment groove 27 from the annular gap formed between the shaft 26 and the housing 28, this pressure is generated between the fixed lip 25 of the packing 21 and the seal lip 24. The fixed lip 25 and the seal lip 24 are guided to the space formed between them so as to spread to the mating member side.

Then, the fixing lip 25 of the packing 21 presses the bottom surface of the packing mounting groove 27 formed on the shaft 26, and the seal lip 24 of the packing 21 presses the inner peripheral surface of the housing 28. Therefore, the pressing force at this time ensures the sealability on the contact surfaces of the fixed lip 25 and the seal lip 24 with respect to the mating member.

However, in the conventional packing as described above, there is a fear that so-called undulation may occur in the seal lip 24.

That is, in the so-called lip type packing 21 as described above, the crushing margin of about 30% at maximum is set in the radial direction in order to obtain the pressing force against the mating member, Generally, a predetermined elastic force is obtained with respect to the member, but when the packing 21 is arranged between both members, the crushing amount of the packing 21 exceeds about 40%. Then, as shown in FIG. 4, the tip of the seal lip 24 is deformed in a wavy manner.

When the seal lip 24 has a waviness in this way, a gap is created between the seal lip 24 and the housing 28 due to the waviness, so that the sealing property is significantly deteriorated. It will be.

In particular, when the inner diameter of the housing 28 has a large variation, when the housing 28 having a small inner diameter is used, the inner peripheral surface of the housing 28 and the packing mounted on the shaft 26 are attached. The distance between the surface facing the bottom surface of the groove 27 may be very small, and as a result, the crushed amount of the packing 21 may exceed 40%.

Therefore, in the conventional case, in order to make the distance between the inner peripheral surface of the housing 28 and the opposing surface of the bottom surface of the packing mounting groove 27 a predetermined dimension, the tolerance of the inner diameter of the housing 28 is reduced. There was a problem that it had to be set.

It is an object of the present invention to solve the above problems and to provide a packing that can satisfactorily seal even when a housing having a large variation in inner diameter is used.

[0019]

[Means for solving problems]

 In order to solve the above-mentioned problems, this invention is an annular rubber-like elastic body which is fitted in an annular packing mounting groove formed in a shaft which is relatively movable in a housing and seals between both members. The packing is formed of an annular seal lip that can come into contact with the housing, and the seal lip has a plurality of lip portions having different diameters.

[0020]

[Action]

 By adopting the above-mentioned means, the present invention is able to flexibly cope with the case of using a housing having a large variation in the inner diameter dimension of each, and perform good sealing.

That is, since the seal lip of this packing has a plurality of lip portions having different diameters from each other, when a housing having a large inner diameter is to be sealed, the lip portion having a relatively large diameter is used. Contacts the inner surface of the housing to seal the contact surface, and when sealing a housing with a small inner diameter, the lip with a relatively small diameter contacts the inner surface of the housing. It comes in contact with and seals this contact surface.

At this time, in the past, since the seal lip was formed by one lip portion, when sealing a housing having a small inner diameter, the crushing amount of the packing becomes large and the waviness at the tip portion of the seal lip However, in this invention, since the lip portions having different diameters are formed in a plurality of steps, even if the lip portion having a large diameter is wavy, The lip portion having a smaller diameter than this is preferably brought into contact with the inner peripheral surface of the housing to achieve good sealing.

Along with this, even when a plurality of housings having different diameters are sealed, if a plurality of lip portions having a diameter corresponding to the inner diameter of the housings are formed to form the seal lip, the seal lip is formed. However, since it is possible to flexibly respond to the inner diameters of the respective housings, one packing can be commonly used for housings having a plurality of inner diameter sizes.

[0024]

【Example】

 Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a diagram showing an embodiment of a packing according to the present invention. That is, the packing 1 shown in FIG. 1 is made of an annular rubber-like elastic body, and when it is fitted in the packing fitting groove 7 of the shaft 6, it is interposed between the shaft 6 and the housing 8 to seal the two members. On one end surface of the packing 1, a fixed lip 5 that can come into contact with the shaft 6 and a seal lip 4 that can come into contact with the housing 8 are formed in an annular shape. Reference numeral 4 denotes a first lip portion 2 that protrudes outward, and a tip portion that protrudes outward from a portion inside the first lip portion 2 and that has a tip portion inward from the tip portion of the first lip portion 2. And a second lip portion 3 located at.

The packing 1 is sealed by the first lip portion 2 when the inner diameter of the housing 8 is large, and is sealed by the second lip portion 3 when the inner diameter of the housing 8 is small. ing.

In FIG. 1, the shaft 6 is inserted into the housing 8 with a slight space therebetween, and is supported by the housing 8 in a rotatable and reciprocating manner.

The shaft 6 inserted into the housing 8 is formed with an annular packing mounting groove 7 opening to the outer peripheral surface of the shaft 6, and the packing 1 is mounted inside the packing mounting groove 7. ing.

The packing 1 is made of a rubber-like elastic body having a good sealing property, and is formed in an annular shape having a substantially U-shaped cross section as a whole. The packing is provided on the inner peripheral side of one end surface of the packing 1. A fixed lip 5 that can come into contact with the bottom surface of the mounting groove 7 is formed annularly, and a seal lip 4 that can come into contact with the inner peripheral surface of the housing 8 is formed annularly on the outer peripheral side.

The seal lip 4 has two annular lip portions having different diameters, that is, a first lip portion 2 and a second lip portion 3. One of the lip portions, the first lip portion 2 is formed so as to project outward from the outer peripheral side of one end surface of the packing 1.

The other second lip portion 3 of the lip portions is formed so as to project outward from the root portion of the first lip portion 2. At this time, the tip portion of the second lip portion 3 should be located inward of the tip portion of the first lip portion 2 so that the outer diameter of the second lip portion 3 becomes smaller than that of the first lip portion 2. Be smaller than the outer diameter of.

Then, the packing 1 is mounted in the packing mounting groove 7 of the shaft 6, and the shaft 6 mounted with the packing 1 is inserted into the housing 8 so that the outer peripheral portion of the packing 1 is inside the housing 8. The packing 1 is arranged such that the packing 1 is in contact with the peripheral surface and the inner peripheral surface of the packing 1 is in contact with the outer peripheral surface of the shaft 6, respectively.

Next, the operation of the above will be described.

By mounting the packing 1 in the packing mounting groove 7 formed on the shaft 6 as in the above-described configuration, the packing 1 is interposed between the shaft 6 and the housing 8, and as a result, A seal is provided between the shaft 6 and the housing 8 in a relatively movable state.

First, when the packing 1 is mounted in the packing mounting groove 7 of the shaft 6, the fixing lip 5 of the packing 1 fixes the packing 1 in the packing mounting groove 7 by tightening the shaft 6 by its elastic force. Thus, the contact surface with respect to the shaft 6 has a sealing property.

On the other hand, the seal lip 4 of the packing 1 is slidably brought into contact with the inner peripheral surface of the housing 8 by its elastic force, so that the abutting surface is provided with a sealing property. Therefore, as a result, both members are sealed by the packing 1 in a state where both members are relatively movable.

Here, when pressure is introduced into the packing mounting groove 7 through the annular gap formed between the shaft 6 and the housing 8, this pressure is generated between the fixing lip 5 of the packing 1 and the seal lip 4. The fixed lip 5 and the seal lip 4 act to spread to the mating member side by being guided to the empty space formed in.

Then, the fixing lip 5 of the packing 1 presses the bottom surface of the packing mounting groove 7 formed on the shaft 6, and the seal lip 4 of the packing 1 presses the inner peripheral surface of the housing 8. Therefore, due to the pressing force at this time, sealing performance is ensured on the contact surfaces of the fixed lip 5 and the seal lip 4 with respect to the mating member.

Further, the packing 1 described above can cope with the case where there is a large variation in the inner diameter of each housing 8.

That is, the seal lip 4 of the packing 1 has a first lip portion 2 having a relatively large outer diameter and a second lip portion 3 having a smaller diameter than the first lip portion 2. Therefore, when sealing the housing 8 whose inner diameter is relatively large within the permissible dimension, the first lip portion 2 makes contact with the inner peripheral surface of the housing 8 for sealing, and the inner diameter is within the permissible dimension. When the housing 8 which is formed relatively small inside is sealed, the second lip portion 3 suitably contacts the inner peripheral surface of the housing 8 to seal.

First, as shown in FIG. 1, when the inner diameter of the housing 8 is formed with the maximum allowable tolerance and the inner peripheral surface of the housing 8 is located on the chain double-dashed line a, for example, the seal lip The first lip portion 4 of No. 4 comes into contact with the inner peripheral surface of the housing 8 in a state of being slightly compressed within the range of the crushing margin of about 30%, whereby a suitable sealing state can be obtained. Become.

Then, when the inner diameter of the housing 8 is formed with the minimum allowable tolerance and the inner peripheral surface of the housing 8 is located on the chain double-dashed line b, the first lip portion 2 of the seal lip 4 is Since the squeezing amount exceeds 40%, undulation occurs at the tip portion and a gap is formed between the crushing portion and the inner peripheral surface of the housing 8, but at this time, the second lip portion 3 of the seal lip 4 is formed. However, since it comes into contact with the inner peripheral surface of the housing 8 in a slightly compressed state within a range of about 30% of the crushing margin, this ensures a good sealed state.

Therefore, in the past, since there was only one lip portion of the seal lip, the inner diameter of the housing should be allowed only within the range from the tip of the lip portion to the crushing amount of 30%. However, in the packing 1 described above, since the lip portion of the seal lip 4 is formed at two places, the inner diameter of the housing 8 is smaller than the tip of the first lip portion 2 of the seal lip 4. The crushing amount from the portion to the second lip portion 3 can be allowed within a range of about 30%.

In other words, in the packing 1, even if the inner diameters of the housing 8 vary greatly, the distance between the facing surfaces of the inner peripheral surface of the housing 8 and the bottom surface of the packing mounting groove 7 in FIG. If it is within the range of m to n, it can be suitably sealed.

Further, the packing 1 can be commonly used for two types of housings 18a 1 and 18b 2 having different inner diameters.

That is, when the housing 18a having a relatively large inner diameter is used, the first lip portion 2 of the seal lip 4 abuts and seals on the inner peripheral surface of the housing 18a. When a housing 18b formed smaller than the housing 18a is used, the second lip portion 3 of the seal lip 4 comes into contact with the inner peripheral surface of the housing 18b to seal.

First, as shown in FIG. 2, the tolerance of the inner diameter of the housing 18a is set between c and d in the figure, and for example, the inner peripheral surface of the housing 18a is located on the two-dot chain line A. In such a case, the first lip portion 2 of the seal lip 4 comes into contact with the inner peripheral surface of the housing 18a in a slightly compressed state within the range of the crushing amount of about 30%. A suitable sealed state will be obtained.

Then, a tolerance of the inner diameter of the housing 18b having an inner diameter smaller than that of the housing 18a is set between e and f in the figure, and for example, the inner peripheral surface of the housing 18b is positioned on the chain double-dashed line B. In this case, since the crushing amount of the first lip portion 2 of the seal lip 4 exceeds 40%, undulation occurs at the tip portion and a gap is generated between the inner peripheral surface of the housing 18b. However, at this time, the second lip portion 3 of the seal lip 4 comes into contact with the inner peripheral surface of the housing 18b in a slightly compressed state within the range of about 30% of the crushing amount. Therefore, a good sealing condition will be secured.

Therefore, in the past, since there was only one lip portion of the seal lip, in order to seal a plurality of types of housings having different inner diameters, the packing in which the outer diameter of the seal lip is set according to the inner diameter of the housing is used. However, in the packing 1 described above, since the lip portion of the seal lip 4 is formed in two places, it is necessary to prepare two types of housings 18a and 18b having different inner diameters. You can share it with others.

In the above embodiment, the lip portion of the seal lip 4 is formed at two places, the first lip portion 2 and the second lip portion 3, but the present invention is not limited to this. That is, the seal lip 4 may be any one as long as it has a plurality of lip portions having different diameters.

[0051]

[Effect of device]

 As described above, in the conventional packing, the seal lip that seals the inner peripheral surface of the housing has only a single lip portion, so if the inner diameter of the housing is small, the seal lip It may not be possible to deal with large variations in the inner diameter of individual housings due to the undulations that occur in the seal. Since it has multiple different lip parts, even if waviness occurs in the lip part with a large diameter when packing is used when there are variations in the inner diameter of each housing, It is possible to cope with a small lip portion, and as a result, the sealing performance can be improved.

In addition, in accordance with this, in the past, since the seal lip had only one lip portion, for the housings of different diameters, the packing of different size was used. In this invention, since the seal lip has a plurality of lip portions having different diameters, one packing can be used for housings of various different diameter sizes. effective.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a packing according to the present invention.

FIG. 2 is a diagram for explaining the operation of the packing according to the present invention.

FIG. 3 is a diagram showing a conventional example.

4 is a diagram showing a cross-sectional view taken along the line CC in FIG.

[Explanation of symbols]

 1, 21 ... packing 2 ... first lip part 3 ... second lip part 4, 24 ... seal lip 5, 25 ... fixed lip 6, 26 ... shaft 7, 27 ... packing mounting groove 8, 18a, 18b, 28 ... Housing

Claims (1)

[Scope of utility model registration request] 1. A ring-shaped packing mounting groove (7) formed in a shaft (6) movably provided in a housing (8) to seal between both members (6) and (8). A packing made of an annular rubber-like elastic body, which forms an annular seal lip (4) capable of contacting the housing (8), and a plurality of lip parts ( Packing characterized in that it has two or three).