JPH11210628A - Air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the heat radiating property of a valve seat member, as well as to improve the corrosion resistance of the valve seat member. SOLUTION: This reciprocating compressor 10 has a cylinder 12 in which a piston 11 reciprocates; a cylinder head 15 having a suction passage 13 and a discharge passage 14; and a valve seat member 18 provided between the cylinder 12 and the cylinder head 15. The valve seat member 18 is formed of a stainless steel member with a corrosion resistance. As a result, not only the abrasion of the valve seat member 18 is prevented, but also it is not necessary to plate metallically the surface of the valve seat member 18, and the generation of a poor valve closing resulting from the peeling of the plating is also prevented. At the upper and the lower surfaces of the valve seat member 18, the first packing 25 and the second packing 26 are assembled in the compressive condition. The first packing 25 and the second packing 26 are formed of a graphite member with a high heat conductivity, and the heat of the valve seat member 18 is transmitted and radiated to the cylinder head 15 and the cylinder 12 through the packings 25 and 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air compressor,
In particular, the present invention relates to an air compressor configured to extend the life of a valve seat member and increase the heat radiation effect.

[0002]

2. Description of the Related Art As an air compressor, there is a reciprocating compressor which sucks, compresses and discharges air by reciprocating pistons. This type of reciprocating compressor includes a cylinder in which a piston reciprocates, a cylinder head having a suction passage and a discharge passage, and a valve seat member interposed between the cylinder and the cylinder head. The valve seat member is formed in a flat plate shape, and is provided with a suction port communicating with the suction passage and a discharge port communicating with the discharge passage. A suction valve seat for opening and closing the suction port and a suction valve plate which is separated from and seated on the suction valve seat in accordance with the reciprocating operation of the piston are mounted on the lower surface side of the valve seat member. Also, on the upper surface side of the valve seat member, a discharge valve seat for opening and closing the discharge port,
A discharge valve plate is attached and detached from the discharge valve seat according to the reciprocating motion of the piston.

A conventional valve seat member is made of a steel plate (SS400), and its surface, suction valve seat and discharge valve seat are N-type.
i-P alloy plating is applied. On the upper and lower surfaces of the valve seat member, a first packing for sealing between the cylinder and a second packing for sealing between the cylinder head and the cylinder head are assembled in a compressed state. Leakage of air from between the head is prevented. Therefore, the valve seat member is mounted on the upper surface of the cylinder via the first packing made of asbestos material, and the cylinder head is mounted on the upper surface of the valve seat member via the second packing made of asbestos material.

Since the compressed air passes through the discharge port of the valve seat member and is discharged to the discharge passage by the reciprocating motion of the piston,
The temperature around the discharge port of the valve seat member increases. The temperature around the suction port of the valve seat member is lower than that around the discharge port because the outside air is introduced and cooled. Since the valve seat member is mounted in a state sandwiched between the cylinder and the cylinder head as described above, it is difficult to radiate heat.
Therefore, a steel plate having a high thermal conductivity (SS4
00), whereby heat around the discharge port of the valve seat member generated by the compression operation of the piston is cooled by air flowing into the suction port of the valve seat member.

[0005]

However, in the conventional air compressor, since the valve seat member is made of a steel plate (SS400), if the Ni-P alloy plating on the surface is peeled off, the valve seat member is easily corroded, and the valve seat member is made of a material. Rust generated on the suction valve seat and discharge valve seat makes it impossible to completely shut off the suction port or discharge port when the suction valve plate or discharge valve plate closes, resulting in a decrease in compression efficiency due to air leakage. become.

For this reason, formation of a valve seat member from a corrosion-resistant stainless steel is being studied. However, when the valve seat member is formed of a stainless steel material, the heat conductivity of the stainless steel material is as small as about の of that of the steel plate (SS400). Occurs. When the heat generated by the compression operation of the piston becomes difficult to radiate in this way, the temperature around the valve seat member and the discharge port rises,
The temperature of the compressed air stored in the air tank rises. Therefore, the apparent pressure of the compressed air discharged from the discharge port is increased, and the amount of the discharged air is reduced, which causes a problem that the efficiency of the air compressor is reduced.

Therefore, an object of the present invention is to provide an air compressor which has solved the above-mentioned problems.

[0008]

In order to solve the above problems, the present invention has the following features. The present invention provides a cylinder in which a piston reciprocates, a cylinder head having a suction passage and a discharge passage, and a suction interposed between the cylinder and the cylinder head, communicated with the suction passage and opened and closed by a suction valve plate. A valve seat member provided with a port and a discharge port communicated with the discharge passage and opened and closed by a discharge valve plate; a first packing for sealing between the cylinder and the valve seat member; A second packing that seals between the valve seat member and the valve seat member, wherein the valve seat member is formed of stainless steel, and at least one of the first packing and the second packing is graphite. It is characterized by being formed of a material.

Therefore, according to the present invention, the valve seat member is formed of stainless steel, and at least one of the first packing and the second packing is formed of graphite, so that the valve seat member can be prevented from being corroded. At the same time, heat generated by the compression operation of the piston can be conducted to the cylinder head and the cylinder via the graphite material having a high thermal conductivity, so that the heat radiation effect can be enhanced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the air compressor according to the present invention. FIG. 2 is a plan view showing a state in which a suction valve plate and a discharge valve plate are attached to a valve seat member. As shown in FIGS. 1 and 2, a reciprocating compressor 10 includes a cylinder 12 in which a piston 11 reciprocates,
It has a cylinder head 15 having a suction passage 13 and a discharge passage 14, and a valve seat member 18 interposed between the cylinder 12 and the cylinder head 15. Also, the valve seat member 18
Are provided with a suction port 16 communicating with the suction passage 13 and a discharge port 17 communicating with the discharge passage 14. The suction port 16 is provided along the center line of the valve seat member 18, and a pair of discharge ports 17 are provided on both sides thereof.

A suction valve plate 19 that opens the valve seat 16a of the suction port 16 in conjunction with the downward movement of the piston 11 is attached to the lower surface of the valve seat member 18. Suction valve plate 1
Reference numeral 9 denotes a free end that opens and closes in opposition to the suction port 16, and the other end is fixed to the valve seat member 18 by a parka tack 19a. Further, the piston 11 is provided on the upper surface of the valve seat member 18.
The discharge valve plate 20 that opens the valve seat 17a of the discharge port 17 in conjunction with the upward movement is mounted in a "C" shape. Above the discharge valve plate 20, a discharge valve plate restricting member 24 for restricting the valve opening operation position of the discharge valve plate 20 is fixed to the valve seat member 18 by mounting bolts 22.

The discharge valve plate 20 has one end fixed to the valve seat member 18 by a mounting bolt 22 and the other end free. Therefore, the free end sides of the suction valve plate 19 and the discharge valve plate 20 are displaced to the valve closing position or the valve opening position due to the pressure difference caused by the reciprocating motion of the piston 11. Valve seat member 1
Numeral 8 is made of a corrosion-resistant stainless steel (SUS430). Therefore, the valve seat member 18 is prevented from being corroded, the surface of the valve seat member 18 does not need to be plated, and a valve closing failure due to peeling of the plating is prevented.

The discharge port 17 of the valve seat member 18 is provided on the upper surface of the valve seat member 18 so as to face the discharge valve plate 20.
, A circular concave portion 21 is formed. The circular recess 21 is cut by an end mill or the like. That is, when cutting is performed using an end mill having the same diameter as the inner diameter of the circular concave portion 21, it is only necessary to fix the valve seat member 18 on a table (not shown) of a milling machine and feed the end mill that is rotationally driven in the axial direction. The circular recess 21 can be processed.

[0014] Therefore, in the process of forming the circular concave portion 21, secondary processing such as grinding is not required as compared with the conventional press working, so only cutting by an end mill is required, and the number of processing steps is reduced to increase production efficiency. Can be. Thereby, the manufacturing cost when processing the valve seat member 18 can be reduced. In the refueling type reciprocating air compressor having the above-described configuration, the piston ring 23 fitted on the outer periphery of the piston 11 slides in the cylinder 12 as the piston 11 reciprocates, and the inner wall of the cylinder 12 The lubricating oil adhering to the surface is scraped off, but a part of the lubricating oil becomes vapor (atomized state) and is included in the compressed air. As a result, the lubricating oil is carbonized to generate carbonized powder.

Accordingly, dust such as the above-mentioned carbonized powder of the lubricating oil accumulates between the discharge valve plate 20 and the valve seat member 18, whereby the deposits are formed when the discharge valve plate 20 is displaced to the closed position. There is a risk that the vehicle will get on the vehicle and the discharge port 17 cannot be completely closed. Therefore, in the reciprocating air compressor, a circular recess 21 is formed between the mounting bolt 22 and the discharge port 17 to prevent a valve closing failure due to the deposit. As a result, the discharge valve plate 20 is prevented from climbing on deposits such as carbonized powder, and the free end side is in close contact with the valve seat of the discharge port 17 due to the valve closing operation of the discharge valve plate 20, thereby reducing the compression efficiency during the compression operation. Can be secured.

On the upper and lower surfaces of the valve seat member 18, a first packing 25 for sealing between the cylinder 12 and a second packing 2 for sealing between the cylinder head 15 are provided.
6 are assembled in a compressed state, and air leakage from between the cylinder 12 and the cylinder head 15 is prevented. The first packing 25 and the second packing 26 are formed of a graphite material having high thermal conductivity. The graphite material is made of graphite having a layered structure in which hexagonal mesh planes of carbon atoms are regularly stacked, and has a property that thermal conductivity is better than asbestos material.

FIG. 3 is a plan view of the first packing 25. As shown in FIG. 3, since the first packing 25 is interposed between the lower surface of the valve seat member 18 and the cylinder 12,
A substantially circular opening 25a facing the piston 11 in the center
A mounting hole 25b as an escape hole of a parka tack 19a for fixing the suction valve plate 19;
2 and an insertion hole 25c for inserting a bolt (not shown) for fastening to 2.

FIG. 4 is a plan view of the second packing 26. As shown in FIG. 4, since the second packing 26 is interposed between the upper surface of the valve seat member 18 and the cylinder head 15, a suction opening 26 a provided at a position facing the suction port 16 is provided. A suction opening 26b provided at a position facing the discharge port 17 and the discharge valve plate 20 and an insertion hole 26c for inserting a bolt (not shown) for fastening the cylinder head 15 to the cylinder 12 penetrate. doing.

FIG. 5 shows a temperature change and a discharge air amount change when the valve seat member 18 is made of stainless steel, and a temperature change and a discharge air amount when the first packing 25 and the second packing 26 are made of graphite material. It is a figure showing a change. The temperature change and the discharge air amount when the combination of the materials of the valve seat member 18, the first packing 25, and the second packing 26 are changed as shown in FIG. Here, experimental results were obtained for two types, the change condition A and the change condition B.

The change condition A is that the material of the valve seat member 18 is changed from “steel plate (SS400), Ni—P alloy plating” to “stainless steel (SUS430)”, and the first packing 25 and the second packing 26 Material is "asbestos material"
This is the case when it is left as it is. The change condition B is a case where the material of the first packing 25 and the second packing 26 is changed from “asbestos material” to “graphite material” with respect to the change condition A.

When the change condition A is performed as described above, since the thermal conductivity of the stainless steel (SUS430) is about half that of the steel plate (SS400), the discharge passage 14
Temperature rises by 5.8 deg, and the temperature of the discharge port 17 rises by 26.6 deg. At the same time, the discharge passage 14
, The amount of air discharged from was decreased by -1.7 L / min. Therefore, the material of the valve seat member 18 is changed to stainless steel, and the valve seat 16a of the suction port 16 and the valve seat 1 of the discharge port 17 are changed.
It can be seen that simply preventing the corrosion of 7a increases the temperature of the discharge passage 14 and the discharge port 17, reduces the amount of discharged air, and reduces the air compression efficiency.

As described above, when the temperature of the discharge passage 14 and the discharge port 17 rises, the compressed air expands due to the temperature, and the apparent pressure rises, so that the air tank (shown in FIG. When the pressure in (z) reaches the upper limit, the operation switches to unload operation. However, even though the pressure of the air tank (not shown) has reached the upper limit, the pressure decreases as the temperature decreases, and the actual amount of compressed air discharged decreases.

On the other hand, when the modification B of the present invention is performed,
Although the material of the valve seat member 18 was stainless steel (SUS430), the temperature of the discharge passage 14 decreased by -6.7 deg, and the temperature of the discharge port 17 decreased by -18.8 deg. At the same time, the amount of air discharged from the discharge passage 14 is
It increased by 2.3 L / min. Therefore, the material of the valve seat member 18 is changed to stainless steel, and the valve seat 16 of the suction port 16 is changed.
a and the valve seat 17a of the discharge port 17 can be prevented from being corroded, and a decrease in the heat radiation effect due to a decrease in the thermal conductivity due to the stainless steel material can be prevented. That is, the material of the valve seat member 18 is made of stainless steel having a low thermal conductivity, and the material of the first packing 25 and the second packing 26 is changed from asbestos material to graphite material having higher thermal conductivity. Valve seat member 18 associated with air compression operation of piston 11
Can be transmitted to the cylinder 12 and the cylinder head 15 via the first packing 25 and the second packing 26.

Therefore, the heat of the valve seat member 18 is transferred to the cylinder 1
The heat is radiated from the radiating fins 12a and the radiating fins 15a of the cylinder head 15. Thereby, the valve seat member 18
Of the compressed air can be prevented from decreasing due to a decrease in the temperature of the compressed air. That is, since the temperature rise of the valve seat member 18 is reduced, the amount of vapor of the lubricating oil adhering to the inner wall of the discharge port 17 and the inner wall of the discharge-side elbow communicated with the discharge port 17 is reduced. The amount can be suppressed. Furthermore, since the carbonized powder does not accumulate on the inner wall of the discharge port 17 and the inner wall of the discharge side elbow, the temperature rise itself of the discharge port 17 and the discharge side elbow is suppressed, and the generation of carbonized powder can be further prevented. This allows
The discharge amount of the compressed air passing through the discharge port 17 and the discharge-side elbow can be secured.

In the above embodiment, the first packing 25 and the second packing 26 that contact the upper and lower surfaces of the valve seat member 18 are described.
The case where both were changed from asbestos material to graphite material having higher thermal conductivity was given as an example. However, the present invention is not limited thereto, and only one of the first packing 25 and the second packing 26 is made of graphite material. It may be formed. In this case, the heat of the valve seat member 18 is dissipated by the radiation fins 12a of the cylinder 12 or the radiation fins 1 of the cylinder head 15.
The heat is radiated from any one of 5a.

[0026]

As described above, according to the present invention, the valve seat member is formed of stainless steel, and at least one of the first packing and the second packing is formed of graphite material. Corrosion can be prevented, and the heat generated by the compression operation of the piston can be conducted to the cylinder head and the cylinder through the graphite material having high thermal conductivity to enhance the heat radiation effect. Therefore, the temperature of the valve seat member can be transmitted to the cylinder and the cylinder head via the packing. Therefore, heat of the valve seat member generated by the air compression operation of the piston is radiated from the radiation fins of the cylinder and the radiation fins of the cylinder head. As a result, a rise in the temperature of the valve seat member is reduced, and a decrease in the discharge amount of the compressed air can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of an air compressor according to the present invention.

FIG. 2 is a plan view showing a state in which a suction valve plate and a discharge valve plate are attached to a valve seat member.

FIG. 3 is a plan view of the first packing 25. FIG.

4 is a plan view of a second packing 26. FIG.

FIG. 5 shows a temperature change and a discharge air amount change when the valve seat member 18 is made of stainless steel;
FIG. 7 is a diagram showing a change in temperature and a change in the amount of discharged air when the packing 26 is made of a graphite material.

[Explanation of symbols]

 Reference Signs List 10 reciprocating compressor 11 piston 12 cylinder 13 suction passage 14 discharge passage 15 cylinder head 16 suction port 16a valve seat 17 discharge port 17a valve seat 18 valve seat member 19 suction valve plate 20 discharge valve plate 25 first packing 26 second Packing

Claims (1)

[Claims] 1. A cylinder in which a piston reciprocates, a cylinder head having a suction passage and a discharge passage, interposed between the cylinder and the cylinder head, communicated with the suction passage and opened and closed by a suction valve plate. A valve seat member provided with a suction port and a discharge port communicated with the discharge passage and opened and closed by a discharge valve plate; a first packing for sealing between the cylinder and the valve seat member; and the cylinder head. A second packing that seals between the valve seat member and the air compressor, wherein the valve seat member is formed of stainless steel, and at least one of the first packing and the second packing is formed. An air compressor characterized by being formed of a graphite material.