JPH062652A - Multistage compression unit - Google Patents

Abstract

PURPOSE:To promote the easing of stress concentration in making the extent of surface pressure in a contacting part smaller by setting the contact of a connection between a piston, having a labyrinth sealing mechanism, and a connecting rod down to a line contact. CONSTITUTION:In a final stage piston 13 of this multistage compression unit, a groove 38 forming a labyrinth sealing mechanism on an impulse surface is installed and a high pressure fluid in a compression space 33 is amde so as not to be leaked into this space as a pressure differential between pressure in this compression space 33 and an interspace in the center of a cylinder block grows larger. The piston 13 is rotatably engaged in a recess 39 of a connecting rod 19 by a pin 40, while it comes into contact with a roller 41 housed in this recess, whereby it secures the degree of freedom for reciprocation without receiving any deformation of a turning shaft on a cylinder 6. In addition, z rear end face 37 of the piston 13 is formed into a semi-cylindrical form, while it is engaged with the recess 39 of the connecting rod 19, through which the roller 41, where pressing force in time of a compression stroke acts, the rear end face 37 are made into a line contact, thus surface pressure is made reducible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multistage compression device,
In particular, it relates to improvement of a piston coupling device of a high-stage compression device.

[0002]

2. Description of the Related Art In a conventional multi-stage compressor, cylinders are arranged in a radial direction with respect to a rotating shaft, and the cylinders are opposed to each other to sequentially compress fluid with a pair of pistons to obtain a high-pressure working fluid. (For example, US Pat. No. 5,033,940).

[0003]

However, in the conventional multi-stage compressor, the piston of the high-stage compressor is formed to have a labyrinth seal mechanism, and the connecting rod and the piston are connected by a spherical body. The contact between the connecting rod and the piston becomes point contact, and there are problems that the connecting rod is scratched at high load and the piston rotates in the cylinder to impair the labyrinth seal function.

The present invention solves the above problems,
An object of the present invention is to provide a multi-stage compression device in which the contact between the connecting portion of the piston having the labyrinth seal mechanism and the connecting rod is brought into line contact to reduce the surface pressure of the contact portion to reduce the concentration of stress.

[0005]

SUMMARY OF THE INVENTION The present invention provides a multi-stage compressor having a plurality of pistons having reciprocating compression elements, and at least one of the compression elements having a piston provided with a labyrinth seal mechanism. A compression device having the labyrinth seal mechanism is configured by a cylinder, a piston arranged in the cylinder and having an end surface formed into a curved surface having an arcuate cross section, and a connecting rod for reciprocally sliding the piston in the cylinder. A recess for accommodating a part of the piston is provided in the recess, and a roller that comes into line contact with the curved surface of the piston is accommodated in the recess.

[0006]

The present invention is constructed as described above,
The piston with the labyrinth seal mechanism and the connecting rod are connected linearly to disperse the stress generated by the front and rear ends of the piston with a large pressure difference so that the stress is not concentrated at the joint between the piston and the connecting rod. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a multi-stage compression device showing an embodiment of the present invention. FIG. 2 is an enlarged sectional view of an essential part showing a piston of the high-stage compression device of the present invention.

A cylinder block 1 is provided with four cylinders 3, 4, 5, 6 so as to form a space 2 in the center thereof. These cylinders are radially arranged at intervals of 90 °, and the cylinders 3,
5 and 4, 6 are facing each other. A rotary shaft 7 is arranged at the center of the space 2. This crankshaft is provided with two cranks 8 and 9 which are 90 ° out of phase with each other.

In the cylinders 3, 4, 5 and 6, pistons 10, 11, 12 and 13 are reciprocally arranged. Reference numerals 14 and 15 denote piston connecting mechanisms, which are connecting rods 16, 17, 18, and 19 connected to the pistons 10, 11, 12, and 13, and yokes 20 and 21 respectively connected to these connecting rods. In the yoke, the sliders 22 and 23 are configured to slide back and forth at right angles to the piston reciprocating direction according to the eccentric rotation of the cranks 8 and 9. Holes 24 and 25 are formed in the center of the slider so as to pass through the cranks 8 and 9, respectively.

The open ends of the cylinders 3, 4, 5 and 6 are closed by cylinder heads 26, 27, 28 and 29, respectively.
Pistons 10, 11, 1 are provided in the cylinders 3, 4, 5, 6.
The compression chambers 30, 31, 32, and 33 are formed by 2 and 13. These compression chambers are sequentially connected by passages 34, 35, 36 formed in the cylinder block 1. These passages are adapted to communicate from the discharge side of each compression chamber 30, 31, 32, 33 to the suction side. Each compression chamber 3
The volumes of 0, 31, 32, and 33 are gradually reduced from the cylinder 3 to the cylinder 6 to form a four-stage compression mechanism. The piston 13 that slides back and forth in the highest stage cylinder 6 is formed in a cylindrical shape, and the rear end surface 37 is formed in a semi-cylindrical curved surface. Moreover, the groove 38 is formed on the sliding surface of the piston 13 to form a labyrinth seal mechanism.

A recess 39 for accommodating the rear end side of the piston 13 is provided at the tip of the connecting rod 19. The piston 13 housed in this recess is the pin 40 and the connecting rod 1
It is rotatably locked at 9. A cylindrical roller 41 that contacts the rear end surface 37 of the piston 13 is housed in the recess 39. The roller and the rear end surface are in line contact with each other. The connecting rod 19 is guided in the sliding direction by a guide piece 42 fixed to the cylinder block 1.

In the multi-stage compression device thus constructed, the piston 1 sliding in the cylinders 3, 4, 5, 6
0, 11, 12, and 13 are driven by the rotating shaft 7 and the piston connecting mechanisms 14 and 15 with their phases shifted by 90 °. Therefore, the fluid that has flowed into the cylinder 3 from the space 2 of the cylinder block 1 in the compression chamber 30
The first stage of compression is performed and is discharged to the passage 34 via the cylinder head 26. The fluid in this passage flows into the compression chamber 31 of the cylinder 4 and flows into the piston 11
And the second stage compression is performed, and is discharged to the passage 35 via the cylinder head 27. Further, the fluid in this passage flows into the compression chamber 32 of the cylinder 5 and flows into the piston 12
And the third stage compression is performed, and is discharged to the passage 33 via the cylinder head 28. Finally, the fluid in this passage flows into the compression chamber 33 of the cylinder 6 and the piston 1
After being compressed in 3, the fourth stage of compression is performed and discharged to the outside. Further, the piston 13 at the final stage of the multi-stage compression device is the compression chamber 30, 31, 32, 3 of each cylinder 3, 4, 5, 6.
Even if the compression ratio in 3 is small, the pressure of the fluid compressed in the compression chamber 33 of the cylinder 6 at the final stage becomes considerably high, and the pressure between this compression chamber and the central space 2 of the cylinder block 1 is increased. When the pressure difference becomes large, a groove 38 forming a labyrinth seal mechanism is provided on the sliding surface so that the high pressure fluid in the compression chamber 33 does not leak into the space 2. This labyrinth seal mechanism increases the resistance by the expansion action of the fluid flowing through the groove 35 formed on the sliding surface of the piston 13 to reduce the fluid leakage.

The piston 13 is a recess 39 of the connecting rod 19.
A pin 40 is rotatably locked in the inside of the cylinder 6 and is brought into contact with a roller 41 housed in the recess, so that the cylinder 6 can freely slide back and forth without being affected by the deformation of the rotary shaft 7. I am trying to secure the degree. Moreover, the rear end surface 37 of the piston 13 is formed in a semi-cylindrical shape, and
By being locked in the recess 39 of the connecting rod 19 via the roller 41, the roller 41, which is acted upon by the pressing force during the compression stroke, comes into line contact with the rear end surface 37 to reduce the surface pressure.

According to the present invention, the connecting portion between the piston 13 having the labyrinth seal mechanism and the connecting rod 19 is provided with a degree of freedom so that the seal mechanism is not damaged.
The surface pressure of the connecting part is reduced to prevent scratches due to stress.

[0016]

As described above, according to the present invention, there are provided a plurality of reciprocating compressors, and at least one of the compressors has a piston provided with a labyrinth seal mechanism. In the above, the compression device having the labyrinth seal mechanism is configured by a cylinder, a piston having an end surface formed into a curved surface having an arcuate cross section, and a connecting rod for reciprocally sliding the piston in the cylinder. The connecting rod is provided with a recess for accommodating a part of the piston, and the roller that makes line contact with the curved surface of the piston is accommodated in this recess, so that the connecting rod and the piston are brought into line contact with the roller, and during the compression stroke. The pressure concentration due to the pressing force on the contact can be mitigated, scratches can be less likely to occur on the contact part, and the rotation of the piston in the cylinder can be suppressed to reduce It is possible to prevent the deterioration of Nsushiru mechanism.

[Brief description of drawings]

FIG. 1 is a sectional view of a multi-stage compression device showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an essential part showing a piston of the high-stage side compression device of the present invention.

[Explanation of symbols]

 6 Cylinder 13 Piston 19 Connecting rod 39 Recess 41 Roller

Claims (1)

[Claims] 1. A plurality of reciprocating compressors, and
In a multi-stage compression device in which a labyrinth seal mechanism is provided in a piston of at least one of these compression devices, a compression device having the labyrinth seal mechanism is provided with a cylinder, and an end face arranged in the cylinder is a curved surface having an arcuate cross section. And a connecting rod that reciprocally slides the piston in the cylinder.The connecting rod is provided with a recess for accommodating a part of the piston, and a roller that makes a line contact with the curved surface of the piston is accommodated in the recess. A multi-stage compression device characterized in that