JP7133373B2 - two stage compressor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-stage air compressor. A two-stage air compressor in which a ring is provided, and a lip ring is provided for maintaining the airtightness of the compression chamber in the swinging type second piston that compresses the air in the second-stage cylinder. It is about structure.

A compressor is generally known as a device for generating compressed air. In Patent Document 1 (Japanese Patent Laid-Open No. 2014-029140), as a prior invention by the applicant of the present application, a portable two-stage compressor provided with rocking pistons called "locking pistons" on the first stage side and the second stage side. is proposed. FIG. 3 shows the two-stage compressor, which is the invention of the prior application.

(Configuration of two-stage compressor)
A two-stage air compressor comprises a crankcase 1, a first-stage cylinder 2 (low-pressure cylinder) provided in the crankcase, and an oscillating piston 3 that oscillates and reciprocates with respect to the first-stage cylinder. , a second-stage cylinder 4 (high-pressure cylinder) provided in the crankcase 1, an oscillating piston 5 that reciprocates while oscillating with respect to the second-stage cylinder, and a motor 7 for driving the piston. , has a motor shaft 8 that rotates integrally with its rotor. The two-stage compressor is also permanently mounted on a pair of twin-barreled air tanks 12 for storing the compressed air produced.

Cylinders 2 and 4 are formed in a cylindrical shape, and cylinder heads 21 and 41 are mounted on the tip sides of the cylinders, respectively, in the same manner as in the prior art. A suction chamber for sucking air and a discharge chamber for discharging compressed air are defined in the cylinder heads 21 and 41, respectively. Piston bodies of oscillating type pistons 3 and 5 are accommodated in the cylinders 2 and 4, respectively, and compression chambers are defined in the respective cylinders.

When the motor 7 is driven, the pistons 3 and 5 connected to the motor shaft 8 reciprocate. During this reciprocating motion, the entirety of the pistons 3 and 5 repeatedly oscillates relative to the cylinders 2 and 4, respectively. A ring (described later) is always in sliding contact.

Each of the pistons 3 and 5 repeats a suction stroke in which air is sucked into the compression chamber from the suction chamber and a compression stroke in which the air in the compression chamber is compressed and discharged to the discharge chamber to generate compressed air. The intake valve opens only during the intake stroke, drawing intake air into the compression chamber.

The air compressed in the first-stage cylinder 2 is delivered to the second-stage side through the discharge chamber of the cylinder head 21 and further compressed in the second-stage cylinder 4 . The high-pressure compressed air generated by the second-stage cylinder 4 is discharged through the discharge chamber of the cylinder head 41 and stored in the external air tank 12 . Compressed air stored in the air tank 12 is used for applications such as a nail driver.

(Structure of oscillating piston)
Next, based on FIG. 4, the configuration of the piston 5 provided in the second-stage cylinder 4 (cylinder for high pressure) will be described in detail. The piston on the first stage side has almost the same configuration as the piston on the second stage side except for the difference in size, so the description thereof will be omitted.

Piston 5 is an oscillating piston commonly referred to as a "locking piston". As shown in FIG. 4, the piston 5 is composed of a piston body 51 housed in the cylinder 4 and a piston rod 52 integral with the piston body. A lip ring 53 (sealing member) for sealing between the piston body 51 and the cylinder 4 is attached to the piston body 51 and fixed by a substantially disk-shaped fixing member 54 .

A circular recess is formed on the upper surface side (the side facing the compression chamber) of the piston body 51 so as to engage with the fixing member 54 in a concave-convex manner. A piston rod 52 integral with the piston body 51 extends from the back side of the piston body 51 . An annular portion 55 is provided on the base end side of the piston rod 52 and is connected to the motor shaft 8 via a bearing 56 and a crankshaft 57 . Since the piston rod 52 and the piston body 51 are integrally formed, the piston body 51 is accommodated in the cylinder 4, and the piston 5 as a whole swings with respect to the cylinder 4. reciprocate.

The piston main body 51 and the fixed member 54 are combined so that the lip ring 53 is interposed therebetween. The lip ring 53 is sandwiched between the piston body 51 and the fixed member 54 , and in this state, the fixed member 54 is screwed to the piston body 51 .

(Function of rippling)
The lip ring 53 functioning as a sealing material is made of a flexible resin material. While the piston body 51 reciprocates and swings left and right within the cylinder, the outer edge of the lip ring 53 is elastically deformed and is always in sliding contact with the inner peripheral surface of the cylinder over the entire circumference without gaps. As a result, the space between the piston and the cylinder is airtightly sealed, and the compressed air in the compression chamber above the piston is prevented from leaking through the gap between the outer periphery of the piston body and the cylinder.

JP 2014-029140 A

In the above-described two-stage compressor, when the piston stops, compressed air remains in the compression chamber inside the cylinder, and in particular, high-pressure compressed air remains in the compression chamber of the second-stage cylinder. Since the air pressure remaining in the second-stage cylinder after the piston stops is high, it interferes with the reciprocating motion of the piston in the cylinder and prevents the compressor from restarting.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a two-stage air compressor for generating high pressure air, the two-stage compressor having a structure that enables quick and reliable restart. That's what it is.
Another object of the present invention is to provide a two-stage compressor having a structure capable of solving problems caused by high-pressure air remaining in the compression chamber of the second-stage cylinder.

For example, the purpose of
An oscillating first piston for compressing the air in the first-stage cylinder is provided with a lip ring for keeping the compression chamber airtight, and the oscillating-type first piston compresses the air in the second-stage cylinder. A two-stage compressor in which the lip ring is also attached to the second piston is permanently installed on a pair of air tanks, and the second-stage intake valve has a notch provided in the upper end surface of the cylinder as a stopper. This is achieved by a two-stage compressor structure having an air pressure relief hole in the compression chamber of the cylinder for venting to the atmosphere (when the first piston stops).

In the two-stage compressor structure, the air pressure release hole may be provided within a range where the second-stage intake valve can come into surface contact with the stopper of the notch provided in the upper end surface of the cylinder.

Further, the two-stage compressor structure may be designed such that the minimum diameter of the air pressure relief hole passage is 1/100 or less of the cylinder diameter.

Further, the two-stage compressor structure may be designed so as to satisfy d/D≦1/100, where d is the minimum diameter of the air pressure relief hole passage and D is the diameter of the cylinder.

In the two-stage compressor of the present invention, the compression chamber of the second-stage cylinder is provided with an air pressure relief hole for opening to the atmosphere. The compression chamber of the cylinder can be rapidly released to the atmosphere. Therefore, it is possible to eliminate obstacles when the piston resumes reciprocating motion (obstruction due to air pressure remaining in the cylinder after the piston stops), and the compressor can be quickly restarted.

Also, in the two-stage compressor of the present invention, the air vent hole for releasing the inside of the second-stage cylinder to the atmosphere is provided at a position that does not directly touch the lip ring of the piston (that is, at this position in the cylinder). , Wear powder from the lip ring is less likely to clog the air vent hole.

Further, in the present invention, the air pressure release hole is formed within a predetermined range (within a range where the intake valve can come into surface contact with a stopper in the notch provided in the upper end surface of the cylinder). By adopting such a structure, while the piston is reciprocating, the intake valve, which is elastically deformed in tandem with the reciprocating movement, constantly hits (repeats) the air pressure release hole. You can expect a "cleaning effect" for In other words, due to the cleaning effect of knocking off the abrasion powder generated from the lip ring that maintains airtightness, the intake valve on the second stage comes into contact with the air pressure release hole and accumulates (wear powder) in the vicinity of the air pressure release hole, causing hole clogging. can be prevented.

If the present invention is not adopted, the minimum diameter of the air pressure relief hole passage is limited to 1/100 or more of the cylinder diameter (0.0122=0.5/41 mm) due to fear of hole clogging. For example, to make a 0.3mm air pressure release hole, the cylinder diameter must be 30mm or less. However, less than one-hundredth (0.007=0.3/41) was made possible by the above-mentioned "cleaning effect" according to the present invention. In other words, the present invention is a technique for minimizing the reduction in filling performance during compression due to the air pressure relief hole.

1 is a diagram showing a first embodiment of a two-stage air compressor (two-stage compressor) according to the present invention; FIG. FIG. 2 is a diagram showing a second embodiment of a two-stage air compressor (two-stage compressor) according to the present invention; It is a figure which shows schematic structure of a two-stage air compressor (two-stage compressor). FIG. 2 is an enlarged view showing a schematic configuration of a second-stage air compression section provided in a two-stage air compressor (two-stage compressor);

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for releasing air pressure in a compression chamber of a second-stage cylinder to the atmosphere in a two-stage air compressor (two-stage compressor).
Since the two-stage compressor of the present invention has the same basic structure as the prior art shown in FIG. 3, the description of the prior art is cited for common points, and the same reference numerals are used in the accompanying drawings. Therefore, the description of the prior art is also used for the configuration of the oscillating type piston having the lip ring and the operation during the compression operation.
Specific embodiments of the present invention will be described below, omitting differences from the prior art.

(First embodiment)
A first embodiment of the present invention will be described mainly based on FIG.
Refer to FIGS. 3 and 4 for configurations common to the prior art.

The two-stage compressor of the first embodiment is similar to the conventional technology shown in FIGS. 3 and 4,
An oscillating piston 3 for compressing the air in the first-stage cylinder 2 is provided with a lip ring for keeping the compression chamber airtight, and the oscillating piston compresses the air in the second-stage cylinder 4. 5 is also provided with a lip ring for keeping the compression chamber airtight.

Further, the two-stage compressor of the first embodiment has an air pressure relief hole 43 for releasing the inside of the second-stage cylinder 4 to the atmosphere. This air pressure release hole 43 is formed in the compression chamber of the second stage cylinder 4 . That is, an air pressure release hole 43 is formed in the second stage cylinder 4 so as to communicate with the compression chamber. Also, the air pressure release hole 43 communicates with the atmosphere through an air pressure release passage 45, and releases the air pressure in the compression chamber of the cylinder 4 after stopping the compressor and before restarting the cylinder. Plays the role of opening to the atmosphere.

As described above, in the two-stage compressor of the present embodiment, the compression chamber of the second-stage cylinder 4 is provided with the air pressure release hole 43 for opening to the atmosphere, so that the air remaining in the compression chamber of the second-stage cylinder 4 is Compressed air that can be generated can be quickly discharged from the inside of the cylinder and released to the atmosphere. Therefore, there is no obstacle (obstruction due to air pressure) when the piston 5 resumes reciprocating motion, and the compressor can be quickly restarted.

Further, as shown in FIG. 1, the air pressure release hole 43 employed in this embodiment is located below the top dead center of the piston and at a position where the lip ring 53 touches (inner peripheral surface of the cylinder 4). An air vent hole 43 is formed. By adopting such a feature, an effect of good compression efficiency above the air vent hole 43 can be expected.

However, since the lip ring 53 of the reciprocating piston 5 is in direct contact with the inner wall of the cylinder 4, wear powder of the lip ring 53 generated along with the reciprocating motion tends to clog the air vent hole 43, and the hole There is a possibility that the air vent hole 43 will not function due to clogging.

Further, when the lip ring 53 of the reciprocating piston 5 stops at a position above the air vent hole 43 (a position closer to the top dead center than the air vent hole 43), the air vent hole 43 moves outside the compression chamber. (i.e. below the compression chamber). When the piston 5 stops at the position where the air vent hole 43 is out of the compression chamber, the air vent hole 43 cannot function substantially, and the air pressure remaining in the compression chamber restarts the compressor. It may be difficult to start.

Therefore, when there is a concern about clogging of the air vent holes described above, obstruction of restarting of the compressor, etc., it is also possible to adopt the second embodiment described below.

(Second embodiment)
A second embodiment of the present invention will be described mainly based on FIG.
Refer to FIGS. 3 and 4 for configurations common to the prior art.

The two-stage compressor of the second embodiment is also similar to the conventional technology shown in FIGS. 3 and 4,
An oscillating piston 3 for compressing the air in the first-stage cylinder 2 is provided with a lip ring for keeping the compression chamber airtight, and the oscillating piston compresses the air in the second-stage cylinder 4. 5 is also provided with a lip ring for keeping the compression chamber airtight.

Further, the two-stage compressor of the second embodiment is
an intake valve 47 for opening and closing an intake port communicating with the second-stage cylinder 4;
a notch 49 functioning as a stopper for the intake valve 47;
- An air pressure release hole 44 for opening to the atmosphere,
have.

The intake valve 47 is composed of an elastically deformable plate-shaped member. This intake valve 47 opens and closes an intake port communicating with the second-stage cylinder 4 each time the second-stage piston 5 repeats reciprocating motion (repeatedly elastically deformed and returned to its original shape in conjunction with the movement of the piston). . When the intake valve 47 is not elastically deformed (that is, in its original state), it closes the intake port. Then, the intake valve 47 is elastically deformed to follow the piston 5 (intake stroke of the piston), thereby opening the intake port and sucking the air compressed on the first stage side into the second stage cylinder 4 .
This intake valve is also provided with the two-stage compressor of the first embodiment described above, but the description thereof is omitted in the first embodiment.

The notch 49 is formed in the upper end face of the second stage cylinder 4 . Since the concave portion is formed by cutting the upper end face of the second-stage cylinder 4, it is called a "notch portion". The notch 49 functions as a stopper for the intake valve 47 interlocked with the piston 5 . Specifically, the bottom (bottom surface) of the notch 49 functions as a stopper. During the intake stroke of the piston 5, the intake valve 47 is elastically deformed to open, and is stopped by hitting the bottom of the notch 49 as a stopper.
The notch portion may be provided in the two-stage compressor of the first embodiment described above.

The air pressure release hole 44 communicates with the atmosphere through an air pressure release passage 46, and serves to release the air pressure in the compression chamber of the cylinder 4 to the atmosphere after the compressor is stopped and before it is restarted. bear. However, the air pressure release hole 44 employed in this embodiment is significantly different from the air pressure release hole 43 provided in the first embodiment described above in the points described below.

In the second embodiment, an air vent hole 44 for opening to the atmosphere is formed in the second stage cylinder 4 at a position where the lip ring 53 of the piston 5 does not come into contact. In other words, the lip ring 53 does not come into contact with the air vent hole 44 during the reciprocating motion of the piston 5 .
By providing the air vent hole 44 at a position that does not directly touch the lip ring 53 of the piston 5 in this manner, the abrasion powder of the lip ring 53 is less likely to clog the air vent hole 44 .

In the second embodiment, the air pressure release hole 44 is formed at a predetermined position of the notch 49 (within a range where the intake valve 47 can make surface contact with the stopper of the notch 49 provided on the upper end surface of the cylinder 4). It is That is, the air pressure release hole 44 is formed at the bottom (stopper) of the notch 49 and at a position where the intake valve 47 elastically deformed following the intake stroke of the piston 5 hits.
By adopting such a structure, while the piston 5 is reciprocating, the intake valve 47, which is repeatedly elastically deformed in conjunction with the piston 5, constantly hits (repeatedly hits) the air pressure relief hole 44. A cleaning effect for the air pressure release hole 44 can be expected. In other words, the abrasion powder generated from the lip ring 53 for maintaining airtightness is prevented from remaining in the vicinity of the air pressure release hole and causing hole clogging due to the cleaning effect of contacting the intake valve 47 on the second stage side and knocking it off. .
Further, while the piston 5 is reciprocating, the intake valve 47 is elastically deformed in conjunction with the reciprocating motion, but as soon as the piston 5 stops, the intake valve 47 returns to its original shape (a shape that is not elastically deformed). A gap is provided between the notch 49 and the bottom surface (air pressure relief hole 44). That is, when the piston 5 stops reciprocating, the original intake valve 47, which is not elastically deformed, faces the air pressure relief hole 44 with a gap (a gap through which compressed air can flow). The valve 47 never closes the air pressure relief hole 44 . Therefore, when the piston 5 stops, the inside of the cylinder 4 is reliably released to the atmosphere through the air pressure release hole 44 without being obstructed by the intake valve 47 . That is, while the piston 5 is reciprocating, the intake valve 47 repeatedly hits the air pressure release hole 44, but once the piston 5 stops, the intake valve 47 is released from elastic deformation and returns to its original shape. Since a gap is provided between the notch 49 and the air pressure release hole 44 at the bottom of the notch 49, the inside of the cylinder is reliably released to the atmosphere.

Further, in the second embodiment, the minimum diameter of the passage 46 communicating with the air pressure relief hole 44 is 1/100 or less of the diameter of the second stage cylinder. That is, d/D≤1/100 where d is the minimum diameter of the passage 46 communicating with the air pressure release hole 44 and D is the diameter of the second stage cylinder.

If the present invention is not adopted, the minimum diameter of the air pressure relief hole passage is limited to 1/100 or more of the cylinder diameter (0.0122=0.5/41 mm) due to fear of hole clogging. For example, to make a 0.3mm air pressure release hole, the cylinder diameter must be 30mm or less. However, the above-mentioned "cleaning effect" according to the present invention was made possible by less than one-hundredth (0.007=0.3/41). In other words, the present invention is a technique for minimizing the reduction in filling performance during compression due to the air pressure relief hole.

1 Crankcase 2 Cylinder on first stage (cylinder on low pressure side)
3 Oscillating type piston on the first stage side (Oscillating type first piston)
4 Cylinder on second stage (cylinder on high pressure side)
5 Oscillating type piston on the second stage side (Oscillating type second piston)
7 Motor 8 Motor shaft 12 Air tank 21 Cylinder head 41 Cylinder head 43 Air pressure release hole 44 Air pressure release hole 45 Air pressure release passage (path)
46 Air pressure release flow path (passage)
47 intake valve (intake valve)
49 Notch (stopper/concave portion with a shape that looks like a notch)
51 Piston body 52 Piston rod 53 Lip ring (seal member)
54 Fixed member 55 Annular portion 56 Bearing 57 Crankshaft

Claims (4)

An oscillating first piston for compressing the air in the first-stage cylinder is provided with a lip ring for maintaining airtightness in the compression chamber, and an oscillating-type first piston for compressing the air in the second-stage cylinder. In a two-stage compressor in which the second piston is also provided with a lip ring for maintaining airtightness in the compression chamber,
The compression chamber of the second-stage cylinder is provided with an air pressure release hole for opening to the atmosphere,
A two-stage compressor , wherein the air pressure relief hole is provided in the second-stage cylinder at a position where the lip ring does not come into contact with the air pressure relief hole . An oscillating first piston for compressing the air in the first-stage cylinder is provided with a lip ring for maintaining airtightness in the compression chamber, and an oscillating-type first piston for compressing the air in the second-stage cylinder. In a two-stage compressor in which the second piston is also provided with a lip ring for maintaining airtightness in the compression chamber,
an intake valve for opening and closing an intake port communicating with the second-stage cylinder;
a notch provided in the upper end surface of the second-stage cylinder and functioning as a stopper for the intake valve;
an air pressure release hole for opening to the atmosphere, provided in the second-stage cylinder at a position where the lip ring of the second piston does not contact;
A two-stage compressor comprising: In the two-stage compressor according to claim 2,
A two-stage compressor according to claim 1, wherein the air pressure release hole is provided within a range where the intake valve can come into surface contact with a stopper of a notch provided in an upper end surface of the second-stage cylinder. In the two-stage compressor according to claim 3,
A two-stage compressor, wherein the minimum diameter of the passage communicating with the air pressure relief hole is one-hundredth or less of the diameter of the second-stage cylinder.

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