JPH0968279A - Swing piston - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swing piston which secures a following property of a lip of a piston ring to the inner peripheral surface even in a low temperature condition. SOLUTION: This swing piston consists of a piston main body 3 furnishing a connecting rod 6 connected to a crankshaft 9, and reciprocating in a cylinder while sliding and swaying; a piston ring 7 having a lip 7b provided to the piston main body 3, and to seal between the piston main body 3 and the cylinder 1; and a backup ring 8 with about a C-shape, provided to the piston main body 3, and being an energizing member to energize the lip 7b of the piston ring 7 to the cylinder 1. And the swing piston 2 in which the direction from the center of the backup ring 8 to the opening; and the long axis direction of the inner periphery of the cross section of the cylinder 1, when the inner periphery of the cross section of the cylinder 1 in the vertical direction to the axial direction of the piston main body 3 in the reciprocating movement while sliding and swaying in the cylinder 1 presents an elliptic form; are made coincide, is composed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing piston used in an air compressor, and more specifically,
The present invention relates to a swing piston used for an air compressor used for an air type vehicle height adjusting device for a vehicle.

[0002]

2. Description of the Related Art A conventional swing piston is an actual open shaft
As disclosed in Japanese Patent Laid-Open No. 32477/1997, a piston body provided with a connecting rod connected to a crankshaft and reciprocating while sliding and swinging in a cylinder and forming a convex spherical surface portion on the outer periphery, and the piston body And a piston ring having a lip portion that seals between the piston body and the cylinder, the piston ring sealing between the inner circumferential side fixed portion fixed to the piston body and the cylinder. The outer peripheral lip portion is formed into an annular plate-like body.

This swing piston is used in an air compressor used in an air type vehicle height adjusting device of a vehicle,
As the piston body slides and swings in the cylinder, the outer peripheral lip of the piston ring moves along the convex spherical surface of the piston body and the inner circumference of the cylinder due to the suction and discharge pressure acting in the cylinder. It is urged toward the surface and comes into sliding contact with the inner peripheral surface of the cylinder to seal between the piston body and the cylinder.

[0004]

However, the above-mentioned swing piston has a problem that when the piston ring is hardened at a low temperature, the outer peripheral lip portion is less able to follow the inner surface of the cylinder. .

SUMMARY OF THE INVENTION It is a technical object of the present invention to provide a swing piston in which the lip portion of the piston ring can follow the inner peripheral surface of the cylinder even in a low temperature state.

[0006]

In order to solve the above technical problems, the present invention provides a piston body which is provided with a connecting rod connected to a crankshaft and reciprocates while sliding and swinging in a cylinder. A piston ring provided on the piston body and having a lip portion for sealing between the piston body and the cylinder, and a biasing member provided on the piston body for biasing the lip portion of the piston ring toward the cylinder. A swing piston consisting of and was constructed.

Preferably, the inner circumference of the cylinder cross section of the piston body in the axial vertical direction in the movement of the piston body from the top dead center to the bottom dead center or from the bottom dead center to the top dead center in the cylinder. In response to the deformation of the circular shape from the elliptical shape to the circular shape again, the biasing member follows the swing from the circular shape to the elliptical shape and again to the circular shape, and swings to bias the lip portion toward the cylinder. Piston is preferred.

More preferably, the biasing member is substantially C-shaped, and the piston is in the direction from the center of the substantially C-shaped biasing member toward the opening and in the movement of the piston body in the cylinder. A swing piston in which the inner circumference of the cylinder cross section in the direction perpendicular to the axial direction of the main body has an elliptical shape and the major axis direction of the inner circumference of the ellipse is the same is desirable.

Further, it is preferable that the outer peripheral surface of the urging member is a swing piston having a spherical shape.

In the swing piston according to the first aspect of the present invention, the lip portion of the piston ring acts along the outer peripheral portion of the piston body and in the cylinder as the piston body reciprocates while sliding and swinging in the cylinder. The suction / discharge pressure and the urging force of the urging member urge the inner peripheral surface of the cylinder into sliding contact with the inner peripheral surface of the cylinder, thereby sealing between the piston body and the cylinder.

Further, at a low temperature, even if the piston ring hardens, the urging member urges the lip portion toward the inner peripheral surface of the cylinder, so that the lip portion can follow the inner peripheral surface of the cylinder. Does not decrease and reliably seals between the piston body and the cylinder.

A swing piston according to a second aspect is the swing piston according to the first aspect.
In addition to the action of the swing piston, in the cylinder of the piston body, in the movement from the top dead center to the bottom dead center and from the bottom dead center to the top dead center in the sliding and swinging reciprocating motion, the piston body axial direction The inner circumference of the cylinder in the vertical direction has a circular shape at the top dead center and an elliptical shape in which the major axis extends as the swing angle of the piston body increases in the process from the top dead center to the bottom dead center. At the bottom dead center, the shape is circular again, and in the process from the bottom dead center to the top dead center, the shape is elliptical as in the process from the top dead center to the bottom dead center. The biasing member has a shape substantially equal to the shape of the cylinder inner circumference, and biases the outer peripheral side lip portion of the piston ring toward the cylinder inner circumferential surface, and the lip portion makes sliding contact with the cylinder inner circumferential surface,
Seal between the piston body and the cylinder.

A swing piston according to a third aspect is the swing piston according to the second aspect.
In addition to the action of the swing piston described above, the urging member has a substantially C-shape, and the piston body slides and oscillates in the direction from the center of the substantially C-shaped urging member toward the opening. By matching the major axis direction of the cylinder inner circumference when the cylinder inner circumference of the cylinder cross section in the direction perpendicular to the axial direction of the piston body in the reciprocating motion is elliptical,
In the motion of reciprocating while sliding and swinging from top dead center to bottom dead center and from bottom dead center to top dead center in the cylinder of the piston body, the substantially C-shaped urging member moves to the top dead center. Then, while receiving a pressing force from the inner circumference of the cylinder to present a circular shape, the outer lip of the piston ring is urged toward the inner circumference of the cylinder.
In the process from top dead center to bottom dead center, the inner circumference of the cylinder cross section in the direction perpendicular to the axial direction of the piston body has an elliptical shape in which the major axis extends as the swing angle of the piston body increases.
When the swing angle of the piston body increases, the substantially C-shaped biasing member expands outward while expanding the opening about the portion facing the opening of the substantially C-shaped biasing member. When the oscillating angle of the piston body is reduced by urging the lip portion toward the cylinder inner peripheral surface while exhibiting a substantially elliptical shape whose major axis is the direction from the center of the C-shaped urging member to the opening Is the direction from the center of the substantially C-shaped urging member toward the opening as the major axis, as the substantially C-shaped urging member narrows inward while narrowing the opening due to the pressing force from the inner circumference of the cylinder. The lip portion is urged toward the inner peripheral surface of the cylinder while exhibiting a substantially elliptical shape. Energized, and in the process from bottom dead center to top dead center, it is roughly elliptical like the process from top dead center to bottom dead center. It urges the lip portion into the cylinder peripheral surface while exhibiting.

Therefore, in the axially vertical direction of the piston body in the reciprocating motion while sliding and swinging from the top dead center to the bottom dead center and from the bottom dead center to the top dead center in the cylinder of the piston body. Following the deformation of the inner circumference of the cylinder cross section, the urging member presents a shape that is substantially equal to the shape of the inner circumference of the cylinder, while urging the outer peripheral lip of the piston ring toward the inner peripheral surface of the cylinder, It makes sliding contact with the inner surface of the cylinder and seals between the piston body and the cylinder.

A swing piston according to a fourth aspect is the swing piston according to the first aspect.
In addition to the action of the swing piston according to any one of claims 3 to 3, since the outer peripheral surface of the biasing member has a spherical shape, there is no risk of damaging the piston ring.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

(Embodiment 1) FIG. 1 is a sectional view of a swing piston of an air compressor used in an air type vehicle height adjusting device for a vehicle of this embodiment, and FIG. 2 is a configuration of the swing piston of FIG. It is a perspective view for every part. Figure 1,
In FIG. 2, reference numeral 1 denotes a hollow cylindrical cylinder of an air compressor for a vehicle, and a valve seat member (not shown) having an intake valve and a discharge valve is provided on the axial upper side of the cylinder 1.

Reference numeral 2 denotes a swing piston which is slidably and oscillated in the cylinder 1 so as to be capable of reciprocating. The swing piston 2 includes a piston body 3 integrally having a connecting rod 6 and a piston ring 7. , And a backup ring 8.

The piston body 3 is composed of a piston upper portion 4 and a piston lower portion 5, an annular step portion 4a is formed on the lower surface outer peripheral side of the piston upper portion 4, and an annular step portion 5a is formed on the upper surface outer peripheral side of the piston lower portion 5. And the connecting rod 6 is integrally provided at the center of the lower surface.

The lower end side in the axial direction of the connecting rod 6 is a crankshaft 9 connected to an output shaft (not shown) of the motor.
It is connected to.

The piston ring 7 for sealing between the piston body 3 and the cylinder 1 is fitted to the annular step portion 5a of the piston lower portion 5 and is fixed by the piston upper portion 4 on the inner peripheral side, and the fixing portion. Is integrally formed on the outer periphery of 7a,
It is composed of an outer peripheral lip portion 7b that seals between the piston body 3 and the cylinder 1, and is made of a resin material having a self-lubricating property and flexibility such as Teflon, etc. Is formed in.

The backup ring 8 as a biasing member has a substantially C shape, and the outer peripheral surface of the backup ring 8 has a spherical shape.

The fixed portion 7a of the piston ring 7 is fitted into the annular step portion 5a of the piston lower portion 5, and then a substantially C-shaped backup ring 8 is arranged on the upper surface side of the piston ring 7, and the piston lower portion 5 is provided with the piston upper portion. By stacking and fixing 4 together, a substantially C-shaped backup ring 8 is arranged in the annular step portion 4a between the piston upper portion 4 and the piston ring 7, and the piston body 3 is radially outward from the outer peripheral side. The swing piston 2 is assembled with the lip portion 7b of the piston ring 7 protruding.

On the upper surface of the piston upper portion 4, a hole 4 for mounting a pin 10 for positioning the backup ring 8 is provided.
b is provided. The pin 10 is assembled in the mounting hole 4b and engages with the opening 8a of the substantially C-shaped backup ring 8, and the piston body 3 of the backup ring 8 is engaged.
By restricting the rotation with respect to the direction of the backup ring 8 from the center toward the opening 8a (the arrow direction in FIG. 2) and the direction perpendicular to the crankshaft 9, that is, the cylinder 1 of the piston body 3 described later. When the inner periphery of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the piston body 3 in the inner movement has an elliptical shape, the inner periphery is aligned with the major axis direction of the inner periphery.

A state in which the assembled swing piston 2 is bent and deformed upward so as to surround the outer circumference of the piston upper portion 3 and press the backup ring 8 inward. Then, the lip portion 7b is bent along the outer periphery of the piston upper portion 4 by inserting into the cylinder 1 and the backup ring 8 tries to restore to the original state. It is possible to form the piston ring 7 that is urged toward the inner peripheral surface of 1.

The swing piston 2 slides in the cylinder 1 from the top dead center to the bottom dead center (lower side in FIG. 1) when the motor is driven, so that the swing piston 2 moves from the intake valve. Atmosphere is sucked into the compression space surrounded by the upper part and the cylinder 1, and the air in the compression space is compressed and discharged by sliding from the bottom dead center to the top dead center (upper side in FIG. 1). Exhaust the atmosphere from the valve.

As the swing piston 2 slides in the cylinder 1, the outer peripheral lip portion 7b of the piston ring 7 is formed.
Is urged toward the inner peripheral surface of the cylinder 1 along the outer peripheral portion of the piston body 3 and by the suction / discharge pressure acting in the cylinder 1 and the urging force of the backup ring 8. It makes sliding contact with the inner peripheral surface and seals between the piston body 3 and the cylinder 1.

Further, in the movement of reciprocating while sliding and swinging from the top dead center to the bottom dead center and from the bottom dead center to the top dead center in the cylinder 1 of the piston main body 3, the piston main body 3
The inner circumference of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the cylinder 1 has a circular shape at the top dead center, and in the process from the top dead center to the bottom dead center, the major axis changes as the swing angle of the piston body 3 increases. It has an elongated elliptical shape, and once again has a circular shape at bottom dead center. In the process from bottom dead center to top dead center, it has an elliptical shape similar to the process from top dead center to bottom dead center, and is approximately C-shaped. Of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the piston body 3 in the direction from the center of the backup ring 8 toward the opening and in the reciprocating motion of the piston body 3 in the cylinder 1 while sliding and swinging. By matching the major axis direction of the inner circumference of the cross section of the cylinder 1 when the inner circumference has an elliptical shape, the substantially C-shaped backup ring 8 exerts a pressing force from the inner circumference of the cylinder 1 at the top dead center. While receiving the circular shape, the lip portion 7b is urged to the inner peripheral surface of the cylinder 1 to reach the top dead center. In the process from the bottom dead center to the bottom dead center, the inner circumference of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the piston body 3 has an elliptical shape in which the major axis extends as the swing angle of the piston body 3 increases. When the swing angle of the main body 3 increases, the substantially C-shaped backup ring 8 expands the opening 8a outward with the portion facing the opening 8a of the substantially C-shaped backup ring 8 as the center. The lip portion 7b is urged toward the inner peripheral surface of the cylinder 1 while exhibiting a substantially elliptical shape having a major axis extending from the center of the substantially C-shaped backup ring 8 toward the opening 8a to swing the piston body 3. When the angle decreases, the pressing force is applied from the inner circumference of the cylinder 1 to approximately C
The letter-shaped backup ring 8 narrows inward while narrowing the opening 8a, and exhibits a substantially elliptical shape whose major axis is the direction from the center of the substantially C-shaped backup ring 8 toward the opening 8a and the lip 7b. Is urged to the inner peripheral surface of cylinder 1,
At the bottom dead center, the lip portion 7b is urged toward the inner peripheral surface of the cylinder 1 again while receiving a pressing force from the inner circumference of the cylinder 1 to form a circular shape. In the process from the bottom dead center to the top dead center, Similar to the process of reaching the dead point, the lip portion 7b has a substantially elliptical shape.
Is urged to the inner peripheral surface of the cylinder 1.

Therefore, the backup ring 8 follows the deformation of the inner circumference of the cross section of the cylinder 1 described above.
The outer peripheral lip portion 7b of the piston ring 7 is urged toward the inner peripheral surface of the cylinder 1 while exhibiting a shape substantially equal to the inner peripheral shape of the cross section of the piston 1. A seal is provided between the main body 3 and the cylinder 1.

In addition, since the outer peripheral surface of the backup ring 8 has a spherical shape, the lip portion 7 of the piston ring 7 is
There is no risk of damaging the inner peripheral side of b.

Therefore, according to the swing piston 2 of the present embodiment, the outer peripheral lip portion 7b of the piston ring 7 is normally operated by the suction and discharge pressure acting in the cylinder 1 and the backup ring 8 to prevent the cylinder 1 from moving. Since it is urged toward the inner peripheral surface, it comes into sliding contact with the inner peripheral surface of the cylinder 1 and seals between the piston body 3 and the cylinder 1.

Further, at low temperature, even if the piston ring 7 hardens, the backup ring 8 urges the outer peripheral side lip portion 7b toward the inner peripheral surface of the cylinder 1, so that the cylinder portion 1 of the lip portion 7b. The ability to follow the inner peripheral surface of is not deteriorated, and the piston body 3 and the cylinder 1 are reliably sealed.

In addition, the backup ring 8 has a substantially C shape, and the sliding direction and the swinging direction of the piston body 3 in the cylinder 1 from the center of the substantially C shape backup ring 8 toward the opening. Since the inner circumference of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the piston body 3 in the reciprocating motion is the elliptical shape, the long axis direction of the inner circumference of the cross section of the cylinder 1 coincides with the swing piston. The backup ring 8 can more reliably follow the deformation of the inner circumference of the cross section of the swing piston 2 of the cylinder 1 in the direction perpendicular to the axial direction due to the movement of 2, and backs up the outer peripheral lip portion 7b of the piston ring 7. Ring 8 is more cylinder 1
Is urged toward the inner peripheral surface of the cylinder 1 to be in sliding contact with the inner peripheral surface of the cylinder 1 to more reliably seal between the piston body 3 and the cylinder 1.

Further, since the outer peripheral surface of the backup ring 8 has a spherical shape, there is no fear of damaging the inner peripheral side of the piston ring 7.

In the present embodiment, the rotation of the backup ring 8 with respect to the piston body 3 is restricted by assembling the pin 10, and the direction from the center of the substantially C-shaped backup ring 8 toward the opening and the piston body 3 are controlled. 3 inner circumference of the cross section of the cylinder 1 when the inner circumference of the cross section of the cylinder 1 in the direction perpendicular to the axial direction of the piston body 3 in the reciprocating motion while sliding and swinging in the cylinder 1 has an elliptical shape However, instead of assembling the pin 10, a convex portion that engages with the opening of the backup ring 8 is provided on the piston upper portion 4, and the piston of the backup ring 8 is formed by this engaging convex portion. By restricting the rotation with respect to the main body 3, the piston body 3 moves forward and backward in the direction from the center of the substantially C-shaped backup ring 8 toward the opening and while the piston main body 3 slides and swings in the cylinder 1. The piston body 3 in the kinematic motion
The major axis direction of the inner circumference of the cross section of the cylinder 1 when the inner circumference of the cross section of the cylinder 1 in the direction perpendicular to the axial direction is elliptical may be matched.

Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-mentioned aspects, but includes various aspects according to the principle of the present invention.

[0037]

As described above, according to the invention of claim 1, in the normal state, the outer peripheral lip portion of the piston ring is formed by the suction and discharge pressure acting in the cylinder and the biasing member. Since it is urged toward the inner peripheral surface, it makes sliding contact with the inner peripheral surface of the cylinder and seals between the piston body and the cylinder. Further, at low temperature, even if the piston ring hardens, the urging member urges the outer peripheral lip portion toward the inner peripheral surface of the cylinder, so that the followability of the lip portion to the inner peripheral surface of the cylinder is improved. Seals between the piston body and the cylinder without lowering. Therefore, it is possible to provide a swing piston in which the lip portion of the piston ring can follow the inner peripheral surface of the cylinder even in a low temperature state.

According to the invention of claim 2, in addition to the effect of the swing piston of claim 1, in the axial vertical direction of the swing piston of the cylinder accompanying the reciprocating motion of the swing piston while sliding and swinging. The biasing member can more reliably follow the deformation of the inner circumference of the cross section of the piston ring, and the lip portion of the piston ring is more biased toward the inner circumference surface of the cylinder to make sliding contact with the inner circumference surface of the cylinder. Seal between the body and cylinder.

Therefore, it is possible to provide the swing piston in which the lip portion of the piston ring can follow the inner peripheral surface of the cylinder even in a low temperature state.

According to the invention of claim 3, a better form of the swing piston of claim 2 is shown. That is, the urging member has a substantially C shape, and the axial direction of the piston body in the direction from the center of the urging member toward the opening and the reciprocating motion of the piston body in the cylinder while sliding and swinging. Since the inner circumference of the cylinder cross section in the vertical direction has an elliptical shape and the long axis direction of the inner circumference of the cylinder cross section is matched, the swing piston reciprocates while sliding and swinging. The backup ring can more reliably follow the deformation of the inner circumference of the cross section of the cylinder swing piston in the direction perpendicular to the axial direction, and the lip portion of the piston ring is urged toward the inner circumference surface of the cylinder. It makes sliding contact with the inner surface of the cylinder and seals between the piston body and the cylinder.

Therefore, it is possible to provide the swing piston in which the lip portion of the piston ring can follow the inner peripheral surface of the cylinder even in a low temperature state.

According to the invention of claim 4, in addition to the effect of the swing piston according to any one of claims 1 to 3, since the outer peripheral surface of the biasing member has a spherical shape, It is possible to provide a swing piston in which there is no risk of damaging the peripheral portion side and the lip portion of the piston ring can follow the inner peripheral surface of the cylinder even in a low temperature state.

[Brief description of drawings]

FIG. 1 is a sectional view of a swing piston of the present embodiment.

FIG. 2 is a perspective view of each component of the swing piston shown in FIG.

[Explanation of symbols]

 1 Cylinder 2 Swing Piston 3 Piston Body 6 Connecting Rod 7 Piston Ring 7b Lip 8 Backup Ring 8a Open 9 Crankshaft

Claims (4)

[Claims] 1. A piston body provided with a connecting rod connected to a crankshaft and reciprocating while sliding and swinging in a cylinder, and a piston body provided in the piston body for sealing between the piston body and the cylinder. A swing piston including a piston ring having a lip portion, and a biasing member that is provided in the piston body and biases the lip portion of the piston ring toward the cylinder. 2. The inner circumference of the cylinder cross section of the piston body in the axial vertical direction when the piston body moves from top dead center to bottom dead center or from bottom dead center to top dead center in the cylinder. The urging member follows the deformation from a circular shape to an elliptical shape and then to a circular shape again, and urges the lip portion toward the cylinder while again exhibiting a circular shape from a circular shape to an elliptical shape. 1 swing piston. 3. The biasing member has a substantially C shape, and the substantially C
The same when the inner circumference of the cylinder cross section in the direction perpendicular to the axial direction of the piston body in the movement of the piston body in the cylinder from the center of the character-shaped biasing member toward the opening has an elliptical shape. The swing piston according to claim 2, wherein the elliptical inner circumference is aligned with the major axis direction. 4. The swing piston according to claim 1, wherein an outer peripheral surface of the biasing member has a spherical shape.