JPH0636308Y2 - Locking piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a locking piston suitable for use in an oil-free reciprocating machine such as an air compressor for a vehicle height adjusting device.

[Conventional technology]

In general, a locking piston of this type is integrally provided with a connecting rod connected to a crankshaft, and a piston main body that reciprocates while swinging in a cylinder, and the piston main body is provided with the piston main body and the piston main body. It is composed of a lip ring that seals the space. The structure for assembling the piston body and the lip ring is disclosed in JP-A-59-136586 or JP-A-59-231261.
The one shown in Japanese Patent Publication is known. Among these conventional techniques, the one disclosed in the above-mentioned Japanese Patent Laid-Open No. 59-136586 is such that a seal sleeve is held by a piston portion and an L-shaped rising from the sleeve portion and slidably contacts a cylinder wall. It is formed into a cup shape from the lip range and is attached to the piston portion, while it is described in Japanese Patent Laid-Open No. 59-2312.
The one disclosed in Japanese Patent No. 61 is composed of a rocking piston having a spherical outer periphery, and the piston ring is integrally assembled with the piston.

[Problems to be solved by the invention]

In the locking piston disclosed in Japanese Patent Laid-Open No. 59-136586 among the above-mentioned conventional techniques, the space between the sleeve portion of the seal sleeve and the lip range is bent in an L-shape, and the rocking piston sways. Since bending deformation is repeated with the cylinder wall due to the movement, this portion has a drawback that it is early fatigued and easily damaged. Further, since the tip end side of the lip range is always in line contact with the cylinder wall, there is a drawback that the tip end side is heavily worn and the life of the seal member is short.

On the other hand, in the rocking piston shown in Japanese Patent Laid-Open No. 59-231261, since the piston ring made of a metal material is adapted to the cylinder bore along with the rocking of the rocking piston, the outer circumference of the piston ring has a spherical shape with high accuracy. It is necessary to finish it, and there is a drawback that it is difficult to process the piston ring. Further, since the piston ring is fixed to the piston and does not have a diametrical expansion force in the direction of pressure contact with the cylinder side, if the piston ring wears during repeated sliding with respect to the cylinder bore, There is a drawback in that the sealing performance with the cylinder bore is reduced.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. The present invention provides a lip ring made of a flexible material on the piston body to improve the sealability between the cylinder and the lip. An object of the present invention is to provide a locking piston capable of preventing the lip portion of the ring from being unevenly worn and improving the durability of the lip ring.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a piston body that is integrally provided with a connecting rod that is connected to a crankshaft, and that reciprocates while swinging in a cylinder, and that is provided in the piston body. In a rocking piston comprising a lip ring for sealing between the outer circumference of the cylinder and the inner circumference of the cylinder, a convex spherical surface having an arcuate cross section is formed on the outer circumference of the piston body, and the lip ring is made of a flexible material. , A radially outer fixed portion that is fixed to the piston body and a convex spherical surface portion of the piston body that surrounds the convex spherical portion from the outside, and projects outward in the radial direction from the fixed portion, and the tip is a free end. It is formed as an annular plate body from the outer peripheral lip portion, and the lip portion is flexibly deformed along the convex spherical surface portion of the piston main body to thereby form the cylinder and the piston. It is adopted comprising a characteristic structure in that so as to seal between the emission body.

[Action]

With the above configuration, when the lip ring made of a flexible material is inserted into the cylinder together with the piston body, the lip portion of the lip ring is flexibly deformed along the convex spherical surface portion of the piston body. When reciprocating while swinging, the lip part of the lip ring can be backed up by the convex spherical surface part of the piston body, the lip part can be reinforced from the back side, and the lip part that curves along the convex spherical surface part It is possible to make sliding contact over the entire surface, and to prevent partial wear of the lip portion.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 and 2 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hollow cylindrical cylinder, and a valve seat member (not shown) having a suction valve and a discharge valve is provided on the axial upper side of the cylinder 1. The suction valve may be provided in the piston body 3 described later.

Reference numeral 2 denotes a rocking piston provided in the cylinder 1 so as to be capable of reciprocating while swinging, and the rocking piston 2 is composed of a piston body 3 and a lip ring 9 described later. That is, the piston body 3 has a disc shape, and an annular step portion 4A is formed on the outer peripheral side of the upper surface, and a lower rod 4 integrally provided with a connecting rod 7 described later at the center of the lower surface, A fixing screw on the upper surface of the lower piston portion 4
Thick disk-shaped upper piston part 6 fixed by 5, 5
It consists of and. Further, according to the present embodiment, the outer circumference of the upper piston portion 6 is curved from the center P of the piston body 3 over a range of inclination angles θ ₂ and θ _{3 that} are equal to the swing angle θ ₁ of the connecting rod 7, which will be described in detail later. It is a convex spherical surface portion 6A formed in an arcuate cross section with a radius R ₁ .

On the other hand, the axially lower end side of the connecting rod 7 projecting from the lower piston portion 4 is connected to a crank shaft 8 connected to an output shaft (not shown) of the motor. The axis O, O of the connecting rod 7 swings with respect to the axis O ', O'of the cylinder 1 within the range of the swing angle θ _{1 by} the rotation of.

Next, 9 is a lip ring that seals between the piston body 3 and the cylinder 1. The lip ring 9 is made of a flexible resin material having self-lubricating property, such as fluororesin.
As shown in the figure, it is formed as a flat annular plate-like body, and is fitted into the annular step portion 4A of the lower piston portion 4, and the upper piston portion 6
The fixed portion 9A on the inner peripheral side fixed by the fixed portion 9A and the fixed portion 9A that projects radially outward from the fixed portion 9A and has a free end, and has a predetermined length so as to surround the convex spherical surface portion 6A of the upper piston portion 6 from the outside. It is composed of a lip portion 9B on the outer peripheral side which is formed with a certain dimension.

The lip ring 9 of this embodiment is formed as described above, and after the fixing portion 9A is fitted to the annular step portion 4A of the lower piston portion 4, the upper piston portion 6 is fixed on the lower piston portion 4 by stacking it. By fixing with screws 5, 5, the locking piston 2 is assembled with the lip portion 9B of the lip ring 9 protruding radially from the outer peripheral side of the piston body 3. Then, by inserting the locking piston 2 into the cylinder 1 by bending the lip portion 9B upward so as to surround the convex spherical surface portion 6A of the upper piston portion 6 and deforming it.
It is possible to form the lip ring 9 in which the lip portion 9B bends in a spherical shape along the convex spherical surface portion of the upper piston portion 6.

According to the locking piston 2 configured as described above,
While the piston body 3 reciprocates in the cylinder 1, it oscillates within the range of the maximum inclination angle θ ₂ (θ ₃ ) with respect to the axes O ′ and O ′ of the cylinder 1, so that the inner peripheral surface of the cylinder 1 The lip portion 9B of the lip ring 9 sandwiched between the convex spherical surface portion 6A of the main body 3 and the center P of the piston main body 3 is bent into a spherical surface having a radius of curvature R ₂ . Since the distance of the radius R ₂ is equal to ½ of the inner diameter of the cylinder 1, when the piston body 3 reciprocates while swinging in the cylinder 1,
The lip portion 9B of the lip ring 9 can be backed up by curving it into a convex spherical surface with the convex spherical surface portion 6A of the piston body 3, and the lip portion 9B can be reinforced from the back side, and the lip portion 9B that curves along the convex spherical surface portion The portion slidingly contacting the inner peripheral surface of the cylinder 1 moves in accordance with the swing of the piston body 3, whereby the lip portion substantially slidably contacts the inner surface of the cylinder, so that the lip portion 9B is a convex spherical surface of the piston body 3. Partial uneven wear between the portion 6A and the cylinder 1 can be effectively prevented.

Further, the lip portion 9B is fitted into the cylinder 1 in a bent and deformed state, and is a free end with respect to the convex spherical surface portion 6A of the piston body 3, so that the piston body 3 has an axis line of the cylinder 1. Even if inclined with respect to O'and O ', the lip portion 9B can be brought into close contact with the inner wall of the cylinder 1 by the restoring force in the radial expansion direction.
Moreover, since a high pressure acts between the convex spherical surface portion 6A and the lip portion 9B, a high sealing property can be maintained even if the lip portion 9B becomes thin due to wear.

Therefore, according to this embodiment, when the piston body 3 reciprocates while swinging in the cylinder 1, the lip portion 9B of the lip ring 9 made of a flexible material is replaced by the convex spherical surface portion 6A of the piston body 3. Reinforcement from the back side can prevent partial uneven wear of the lip portion 9B, and the tip side of the lip portion 9B, which is a free end, is brought into sliding contact with the inner peripheral surface of the cylinder 1 for high sealing performance. It can be secured, and reliability and durability can be greatly improved.

Further, since the convex spherical surface portion 6A of the piston body 3 is surrounded by the lip portion 9B without directly contacting the inner peripheral surface of the cylinder 1, it is not necessary to process the convex spherical surface portion 6A with high precision, and it is possible to process the convex spherical surface portion 6A. The workability of can be improved.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of the second embodiment is that it constitutes a locking piston 21, and has a fixing portion 22A on the inner peripheral side and a lip portion 22B on the outer peripheral side. The lip portion 22B of the lip ring 22 consisting of is slightly curved toward the upper piston portion 6B. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof is cited.

With this configuration, the locking piston 21
When inserting into the cylinder 1, the lip portion 22B of the lip ring 22 can be relatively easily deformed and fitted into the cylinder 1, so that the assembling workability can be improved and the first embodiment The sealability similar to that of the lip ring 9 can be maintained.

In each of the above-described embodiments, the lower piston portion 4 is provided with the annular step portion 4A for fitting the lip rings 9 and 22, but the upper piston portion 6 is provided with the annular step portion on the lower surface side. Is also good.

[Effect of device]

Since the present invention is configured as described in detail above, when the piston body reciprocates while swinging in the cylinder, the lip portion of the lip ring made of a flexible material is projected along the convex spherical surface portion of the piston body. While being curved in a spherical shape, the inner peripheral surface of the cylinder can be evenly slid over the entire surface, and partial wear of the lip portion of the lip ring can be effectively prevented. The lip portion of the lip ring is flexibly deformed along the convex spherical surface of the piston body and is inserted into the cylinder, so that a restoring force in the radial direction can always be applied. The tip end side of the portion can be brought into sliding contact with the inner peripheral surface of the cylinder to ensure high sealing performance, and the reliability and durability of the locking piston can be significantly improved. Further, it is not necessary to process the convex spherical surface portion of the piston body with high accuracy, and workability during processing can be improved.

[Brief description of drawings]

1 and 2 show a first embodiment of the present invention.
FIG. 2 is a vertical cross-sectional view showing the locking piston inserted into the cylinder, FIG. 2 is an enlarged view of a main part of the locking piston before the cylinder is inserted, and FIG. 3 is a locking piston according to the second embodiment. It is a principal part enlarged view shown similarly to a figure. 1 ... Cylinder, 3 ... Piston body, 6A ... Convex spherical surface, 7 ...
Connecting rod, 8 ... crankshaft, 9,22 ... lip ring, 9A, 22A ... fixed part, 9B, 22B ... lip part.

Claims (1)

[Scope of utility model registration request] 1. A piston body integrally provided with a connecting rod connected to a crankshaft and reciprocating while swinging in a cylinder; and an outer circumference of the piston body and an inner circumference of the cylinder provided in the piston body. And a lip ring that seals the space between the piston body and the piston body, and a convex spherical portion having an arc-shaped cross section is formed on the outer periphery of the piston body, and the lip ring is fixed to the piston body by a flexible material. A circle from the inner peripheral side fixed portion and the outer peripheral side lip portion that projects radially outward from the fixed portion with a length dimension that surrounds the convex spherical surface portion of the piston body from the outside, and the tip is a free end. It is formed as an annular plate body, and the lip portion flexibly deforms along the convex spherical surface portion of the piston body to seal between the cylinder and the piston body. Locking pistons, characterized in that the the.