JPS62153581A - Reciprocating compressor - Google Patents

Abstract

PURPOSE:To remove the lateral load of a piston, by disposing a guide coupled to a crank pin and moving in the vertical and lateral directions, in a guide sliding only in the vertical direction so that the later mentioned guide transmits the drive force of the crank pin to a piston coupling section. CONSTITUTION:A vertically and laterally movable first slider 35 coupled to a crank pin 33 through a bearing 54, is disposed, slidably in the lateral direction, in a second slider 36 slidable only in the vertical direction on a slide guide 59 which is disposed on cylinders 31, 31a. Further, the vertical outer surfaces of the second slider guide 36 abut against the abutting parts 58, 58a of a piston coupling section 44, and therefore, the force of the crank pin 33 is transmitted to pistons 32, 32a. With this arrangement no lateral load produced by the crank pin 33 is transmitted to the pistons 32, 32a due to slips on the abutting parts 58, 58a.

Description

[Detailed Description of the Invention] <Industrial Application Field> - This invention relates to a reciprocating compressor, and in particular to a self-lubricating material that reduces piston lateral load, prevents wear of piston rings and rider rings, and is oil-free. It is a material that facilitates the application of

<Prior art> As a conventional reciprocating compressor, for example, Japanese Patent Application Laid-Open No. 58-1043
There is one described in 'i' No. 4 publication. This has a configuration as shown in FIGS. 5 and 6. That is, the reciprocating compressor 1 rotates a drive shaft 3 via a pulley 2, and a pin 4 eccentrically provided on the drive shaft 3 engages a piston body 5.
are reciprocated to alternately suck gas into the cylinder chambers 6, 7, compress it, and discharge it. In the figure, 12 is a suction valve, and 13 is a discharge valve.

The piston body 5 has pistons 8.9 at both the upper and lower ends in the figure.
The pistons 8 and 9 are integrally connected by a connecting part 10, and the connecting part 10 has a long hole 11 bored in a direction perpendicular to the piston axis at an intermediate position. .

The pin 4 is inserted into the elongated hole 11, and the circular motion of the pin 4 in the direction of the piston axis is applied to the piston body 5 through the elongated hole 11, causing the piston body 5 to reciprocate. be. The outer circumference of the piston 8.9 is provided with a general piston ring and a rider ring.

This reciprocating compression 'a1 is caused by the piston body 5 of the pin 4 moving in a circular motion drawing a circular locus 14 in FIG.
The contact position for the piston 8.9 reciprocates in the lateral direction within the elongated hole 11 away from the central axis 15 of the piston 8.9, but the piston 8.
．． The force transmitted to piston 9 exerts a moment on piston 8.9, creating a lateral load on piston 8.9. This lateral load has the problem of increasing wear on the piston ring and rider ring.

As a structure for reducing such a lateral load on the piston without increasing the size of the device, there is an offset method described in Japanese Utility Model Publication No. 10446/1983, which uses a connecting rod.

To explain the offset method, in the case of a normal symmetrical type that is not an offset method, the central axis 19 of the cylinder passes through the center 18 of the circular locus 17 drawn by the crank pin 16, as shown in Figure 7. On the other hand, in the case of the offset method, as shown in FIG. 8, the center 18 of the circular locus 17 and the central axis 19 of the cylinder are shown as eccentricity e in the figure, so that the rotation direction (direction of arrow 21) and (top dead center) side) eccentrically in the opposite direction. In the configurations shown in FIGS. 7 and 8, when gas pressure is applied to the piston, the piston forces A, , A' are
It is divided into two directional forces C and C' and a lateral load BXB' in a direction perpendicular to one central axis of the cylinder. At the same crank angle, these two factors are different between the symmetrical type and the offset type. In other words, in the compression stroke, the lateral load B' of the offset type is smaller than the lateral load B of the symmetrical type.

However, even with this offset method, the lateral load is at most IA compared to a symmetrical type. Moreover, it cannot be applied to the type of compressor that does not use a connecting rod as shown in FIGS. 5 and 6.

Separately, self-lubricating piston rings and rider rings, such as those used in conventional oil-free compressors, are subject to severe wear when subjected to large lateral loads, and their lifespan is significantly shortened.

<Problems to be Solved by the Invention> In a conventional compressor in which a long hole is provided in the piston body and a pin is inserted through the long hole and rotated to drive the piston back and forth, A load is generated, which causes the problem of significantly shortening the wear of the self-lubricating piston ring and rider ring.

The technical problem of this invention is to reduce the conventional size of a compressor that does not use a connecting rod, that is, a type that drives a piston reciprocatingly by inserting a rotating pin into a long hole provided in a conventional piston body. The purpose is to remove the lateral load acting on the piston without overturning it.

Means for Solving the Problems> The means of the present invention is to provide a pair of cylinders with their central axes aligned and with their cylinder heads facing outward, and to accommodate both cylinders slidably within the cylinders. are provided with a pair of pistons connected by a connecting portion, and a pin perpendicular to a predetermined plane containing the central axis of the cylinder is driven to rotate along the predetermined plane to reciprocate the piston via the connecting portion. In the reciprocating compressor configured as above, the opposing portion is formed in the connecting portion so as to face each other at a distance on the central axis of the cylinder between the two pistons, and the central portion is Rotatably supported by a pin and centered in the cylinder? il r,'+Force inward dimension A first slider formed to have a dimension sufficiently smaller than the interval dimension of the opposing portion, and a first slider provided on the cylinder side so as to move in the direction of the cylinder center axis between the two cylinders. a first slider guide that guides the first slider by moving along the predetermined plane and in a direction perpendicular to the cylinder center axis; and a second slider having an abutting portion that abuts on the cylinder center axis.

Function> In this invention, the first slider also makes a turning movement due to the turning movement of the pin. The rotational movement of the first slider is
The first slider can move along the first slide guide of the second slider in a predetermined direction perpendicular to the cylinder center axis, and the second slider can move along the second slider guide in the direction of the cylinder center axis. be done. That is, the first slider reciprocates in a direction perpendicular to the cylinder center axis relative to the piston and second slider while both the piston and the second slider reciprocate along the cylinder center axis. The pivoting motion of the first slider gives the second slider a reciprocating motion in the direction along the cylinder center axis, and the reciprocating motion is given to the piston through the opposing portion of the connecting portion. Since the opposing portion is located on the cylinder center axis, the line of action of the force applied to the piston in the direction of the cylinder center axis through the opposing portion always coincides with the cylinder center axis, that is, the piston center axis.

Furthermore, since the gas pressure acting on the piston always acts equally on the piston, the acting force can be replaced with an acting force along the piston center axis.

Therefore, the acting force from the pin that drives the piston against the gas pressure and the reaction force due to the gas pressure always act along the same straight line, and no moment is generated by these two forces.

Note that the movement of the first slider in the direction perpendicular to the cylinder center axis only moves the point of application of the force applied to the second slider, and the application of the force applied from the second slider to the piston side moves. The point remains that the abutting part of the second slider and the opposing part on the piston side always move on the cylinder center axis, so this is a factor that causes lateral loads to act on the piston side during the force transmission process between them. There isn't.

<Example> A first example is shown in FIGS. 1 and 2. In the figure, 3
0 indicates the entire compressor, 31.31a indicates the cylinder, 32
．． 32a is a piston, 33 is a pin, 35 is a first slider, and 36 is a second slider.

As illustrated, the cylinders 31.31a are integrally formed with the cylinder heads facing outward and the central axes y of each cylinder aligned. Each cylinder head is provided with a valve seat plate 40.40a, and each cylinder head is provided with a valve seat plate 40.
1a and discharge valves 41 and 42a are provided.

The pistons 32.32a each have a corresponding cylinder 31.32a.
31a, forming a cylinder chamber 43.43a. Both pistons 32.32a are integrally connected by a joint casting. The connecting portion 44 has a flat arm shape that includes the cylinder center axis y on each piston side, but the intermediate portion is curved away from the cylinder center axis y to form a substantially U-shaped side surface, as shown in FIG. It is curved and wide as shown by the dotted line in FIG. 1, and has an elongated hole 45 through which the pin 33 passes. In addition, each piston 3 is connected to this connecting portion 44 on the cylinder center axis y.
Opposing part 37.37a at the position facing from the 2.32a side
A protrusion is provided as a protrusion. In the figure, 46.46a is a built-up part for balance.

The pin 33 is connected to a drive shaft 47 that is rotationally driven by a motor.
The drive shaft 47 is eccentrically installed in the cylinder 31.
31a is supported via a bearing on an axis perpendicularly crossing the cylinder center axis y. When the drive shaft 47 is rotated, the pin 33 turns in a circular locus 49 shown in FIG. pin 33
passes through the first slider 35, the second slider 36, and the connecting portion I, and its end beyond which it passes is eccentrically coupled to the driven shaft 50.

The portion where the pin 33 passes through the connecting portion 44 is the elongated hole 45.
It is. The driven shaft 50 is supported by a bearing 51 on the opposite side of the intermediate position of the cylinder 31.31a with its axis aligned with the drive shaft 47.

The first slider 35 is a substantially rectangular plate-like body, and the pin 33 passes through the center of the plate surface.
3 via a needle bearing 54, and the edge portions corresponding to the two opposing sides of the quadrangle have a dimension between the edges that is sufficiently smaller than the spacing dimension of the opposing portion 37.37a. sliding surfaces 55 that are parallel to each other and whose edges are parallel to each other.
．． 55a.

The second slider 36 is a horizontally elongated groove-shaped member having a U-shaped cross section, and its longitudinal middle portion is inserted inside the U-shaped bent portion of the connecting portion 44, and the second slider 36 is attached to the bottom wall of the groove. A long hole 56 coinciding with the long hole 45 is drilled in the corresponding portion, and the pin 33 passes through the long hole 56, and the inner surfaces on both sides of the portion corresponding to the groove side walls are formed as first slig guides 57.57g. and the first slider 35 is housed inside so as to be able to slide in the direction of the groove, and the outer surface of the portion corresponding to the groove side wall abuts the opposing portion 37.37a at the contact portion 58.58a, Both ends in the longitudinal direction are guided by second slide guides 59.59 provided on the inner surface of the intermediate portion of the cylinder 31.31a parallel to the cylinder center axis my, so that the cylinder moves along the cylinder center axis y. The first slider guide 5 pa of the second slider 36, 5
The direction 7a is along the turning surface of the pin 33 and perpendicular to the cylinder center axis yK. However, the inner surfaces of the elongated holes 45 and 56 do not contact the pin 33, and the short diameters are similar to the pin 33.
The diameter of pin 33 is also a little larger, and expands in the long axis direction along its short axis width, and the long axis is slightly larger than the sum of the turning diameter of pin 33 and the diameter of pin 33.

In the figure, 60 is a washer, 62.63 is a bearing box, 64.6
4a is a piston ring. Note that the first slider 35
The first slider guide 57.57a is not limited to a rectangular shape.
It may also be a cylindrical roller that rolls and contacts.

In this reciprocating compressor 30, when the drive shaft 47 is rotationally driven, the pin 33 rotates, and the first slider 35 rotates accordingly. The turning movement of the first slider 35 is caused by the first slider guides 5'i, 5 of the second slider 36.
7a in a direction perpendicular to the cylinder center axis y, and also reciprocates in the direction along the cylinder center axis y together with the second slider 36 and the piston 32.32a. At this time, the reciprocating movement of the piston 32.32g in the direction along the cylinder center axis y sucks in gas through the iC suction valve 41.41a in the cylinder chamber 43.43a, compresses it, and discharges it through the discharge valve 42.42a. Dispense. Then, the first slider 3 is moved from the pin 33 at that time.
5. The line of action of the component of the force transmitted to the piston 32.32a side via the second slider 36 in the direction of the piston center axis always passes through the cylinder center axis y. That is, the force is transmitted from the second slider 36 to the piston 32.32a side through the contact portion 58.58a of the second slider and the opposing portion 37.37a that is always in contact with this on the cylinder center axis y.
This is because it is done through. Also piston 32.32
There is no component of the force transmitted to the a side in the direction perpendicular to the piston center axis y.

Therefore, no lateral loads act on the pistons 32, 32a of this reciprocating compressor 1. This greatly reduces wear and extends the life of self-lubricating piston rings and rider rings when used.

A second embodiment is shown in FIGS. 3 and 4. The main differences between the second embodiment and the first embodiment are that the driven shaft 50 is omitted and the pin 33 is a cantilevered pin 33', and that the connecting portion of the piston 32.32a is The point is that the connecting member 70 is formed separately from the piston.

Since the pin 33' is supported on a cantilever, the drive shaft 4
The width of the bearing 48 of No. 7 is increased, and the long hole force through which the pin 33' passes through the connecting portion Off 0 and the second slider 36 is eliminated. In addition, 71.71a in the figure is a rider ring.

Since other points are the same as those in the first embodiment, parts equivalent to those in the first embodiment are indicated by the same reference numerals in the drawings, and description thereof will be omitted. Further, the operation is similar to that of the first embodiment, and similarly, when a self-lubricating piston ring or rider ring is used, the bruising caused by the piston ring is alleviated.

In the above embodiment, the opposing portions 37.37a are formed as raised portions, and the contact portions 58.58a are simply flat surfaces, but the shape is not particularly limited, and the point is that the contact is close to a point. It is enough if you can get it.

<Effects of the Invention> According to the present invention, it is possible to eliminate the lateral load on the piston in a reciprocating compressor that does not use a connecting rod, which is advantageous for downsizing, thereby reducing wear when using a self-lubricating piston ring or rider ring. This has the effect of significantly reducing the Therefore, it is possible to use the compressor as an oil-free compressor used for compressing special gases, and it also has the effect of being compact and compact with the same capacity.

[Brief explanation of drawings]

FIG. 1 shows a first embodiment of the invention, and s+-3 in FIG.
+ sectional view, Figure 2 is a partial longitudinal side view of the first embodiment, Figure 3 is a partial vertical side view of the first embodiment.
The figure shows a second embodiment of the invention.
! 4 is a partial vertical view (near side view,
Figure 5 shows an example of a conventional reciprocating compressor.
-351 side view, Figure 6 is a partial cross-sectional side view of a conventional example, Figure 7 is an explanatory diagram of lateral load B of a type of compressor that uses a conventional connecting rod, and Figure 8 is a conventional connecting rod. FIG. 2 is an explanatory diagram of lateral load B' when a compressor using an offset type is used. 30... Reciprocating compressor, 31.31a... Cylinder, 32.32a... Piston, 33.33'...
Pin, 35...First slider, 36...Second slider, 37.37a...Opposing part, 44.70...Connection part (connection member), 47...Drive shaft, 57.57a...・・・
First slider guide, 58.58a... Contact portion, five... Second slider guide, y... Cylinder center axis. Patent applicant Osamu Shiraki Air Brake Co., Ltd.
Person Tetsu Shimizu and 2 other father-in-laws 1 Figure 2nd CI + Figure 7 Hikara 8th

Claims (1)

[Claims] (1) A pair of cylinders is provided with their central axes aligned and the cylinder heads facing outward, and a pair of pistons are provided that are slidably housed within the cylinders and are connected by a connecting portion. , a reciprocating compressor configured such that a pin perpendicular to a predetermined plane containing the central axis of the cylinder is driven to rotate along the predetermined plane to reciprocate the piston via the connecting portion, an opposing portion formed in the connecting portion so as to face each other at a distance on the center axis of the cylinder between the pistons, and a center portion rotatably pivoted to the pin so that the cylinder center axis direction dimension is opposite to the above. The slider is guided by a first slider formed to have a size sufficiently smaller than the interval between the two cylinders, and a second slider guide provided on the cylinder side so as to move in the direction of the cylinder center axis between the two cylinders. A first slider guide is provided on the inside for guiding the first slider to move along the predetermined plane and in a direction perpendicular to the cylinder center axis; A reciprocating compressor, comprising: a second slider having an abutting portion in contact with the second slider.