JPH03194174A - Suction valve mechanism of reciprocative compressor - Google Patents

Abstract

PURPOSE:To provide a suction valve with capability of quick opening by forming a suction hole in a valve plate interposed between a cylinder block and a housing, giving a larger roughness to that area of the suction hole which is mating with the suction valve, than the other areas, and thereby weakening the tight contacting force of the suction valve with the valve plate. CONSTITUTION:In a reciprocative compressor, for ex. a compressor with swinging swash plate, a piston 1 to be engaged with the swash plate when a rotary shaft rotates, is reciprocated within a cylinder bore 2 formed in a cylinder bock 3, and thereby the fluid sucked from a suction hole 10 provided in a valve plate 9 is compressed and discharged via a discharge hole 11. These suction hole 10 and discharge hole 11 are opened and shut by a suction valve 12 and a discharge valve 13 consisting for ex. of a reed valve. Therein the surface roughness of the valve plate 9 shall for ex. range between 1-2Rz, and that area of the suction hole 10 which contacts the foremost seal part 12a of the suction valve 12 shall have a surface roughness for ex. of 15Rz, and thus a ring-shaped rough surface part A is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION 1] Industrial Application Field The present invention relates to a suction valve mechanism for a reciprocating compressor that performs compression by reciprocating movement of a piston.

[Prior Art] This type of reciprocating compressor, for example, a rocking swash plate compressor (
In the wobble type compressor), as shown in Figure 3,
A cylinder bore 2 in which the piston 1 is accommodated so as to be able to slide back and forth.
A front housing 5 having a crank chamber 4 formed therein is fixed to the front end surface of the cylinder block 3, and a rear housing 8 having a suction chamber 6 and a discharge chamber 7 formed therein is fixed to the rear end surface thereof. Bolt through 9 (
(not shown). The valve grate 9 has the suction chamber 6 and the discharge chamber 7 connected to the cylinder bore 2.
A suction hole 10 and a discharge hole 11 that communicate with each other are formed respectively, and the suction hole 1 is formed on the cylinder block 3 side.
A suction valve 12 that opens and closes the discharge hole 1 is located on the discharge chamber 7 side.
Discharge valves 13 for opening and closing the discharge valves 1 and 1 are respectively provided. In order to prevent the suction valve 12 and the discharge valve 13 from bending toward the opening side more than necessary, a retainer 14 is provided on the back side of the discharge valve 13, and the suction valve 14 is provided at the end of the cylinder bore 2.
A locking recess 15 is formed for locking the tip of 2. Further, the return refrigerant gas from the external cooling circuit is directly introduced into the suction chamber 6 from a suction boat 16 that opens into the suction chamber 6.

[Problems to be Solved by the Invention] Lubricating oil exists in the form of mist in the pressure am, and the surfaces of the valve plate 9 and the suction valve 12 are coated with the lubricating oil. Further, in the conventional compressor, the valve plate 9 has a smooth surface (surface roughness of about 6Rz) to prevent seal leakage and obtain high volumetric efficiency. Therefore,
When the suction valve 12 is pressed against the valve plate 9 during the compression stroke, the suction valve 12 is in close contact with the valve plate 9 due to the surface tension of the lubricating oil that exists between the suction valve 12 and the valve plate 9. Become.

When the compression stroke shifts to the suction stroke, the suction valve 12 is not quickly separated from the valve plate 9, and the pressure in the suction chamber 6 overcomes the surface tension and adhesive force of the lubricating oil, as shown in FIG. As shown, the portion of the suction valve 12 corresponding to the suction hole 0 is bent so as to be convex toward the piston 1 side, and then separated from the valve plate 9.

Therefore, self-vibration occurs between when the suction valve 12 separates from the valve plate 9 and until it comes into contact with the locking recess 15, and this automatic vibration generates suction pulsation and causes the evaporator of the external cooling circuit to resonate. This has the disadvantage that it generates abnormal noise, which causes noise inside the vehicle.

Particularly in the case of a wobble-type compressor in which the refrigerant dregs returned from the external cooling circuit is directly introduced from the suction boat 16 into the suction chamber 6, the evaporator is likely to resonate due to suction pulsation.

Also, when operating a variable capacity compressor with a small capacity, the suction valve 1
Even if the suction valve 2 is opened, its tip may not come into contact with the locking recess 15. In that case, the self-excited vibration continues until the suction valve 12 is closed, and the problem becomes more pronounced. Although this inconvenience can be alleviated by reducing the depth of the locking recess 15, there arises a problem in that this creates suction resistance, lowers suction performance, and lowers cooling efficiency.

Further, in the case of a small capacity operation where the stroke of the piston is small, if the opening timing of the suction valve 12 is delayed, a predetermined amount of suction refrigerant gas may not be sucked into the compression chamber, and there is a possibility that the cooling efficiency will decrease.

The present invention has been made in view of the above problems, and includes:
The purpose is to prevent the resonance of the evaporator caused by the automatic vibration of the suction valve, and to reduce the generation of abnormal noise.
To provide a suction valve mechanism for a reciprocating compressor in which a suction valve is smoothly opened and closed even during small capacity operation and a predetermined amount of suction refrigerant gas is reliably sucked into a compression chamber.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a reciprocating pressure a'lI! which performs compression by reciprocating movement of a piston housed in a cylinder block. In A, the surface roughness of the portion corresponding to the suction valve around the suction side of the suction hole formed in the valve grate interposed between the cylinder block and the housing was made rougher than other portions.

[Operation] Therefore, in the compressor of the present invention, when the pressure in the cylinder bore decreases due to the forward movement of the piston from the open state of the suction valve,
The refrigerant gas in the suction chamber enters the portion of the valve plate with large surface roughness around the suction hole. This pushes away the lubricating oil present between the suction valve and the valve plate, weakening the adhesion of the suction valve to the valve plate, and making it easier to open the suction valve. Therefore, the suction valve separates from the valve plate before it flexes enough to cause self-oscillation, and self-oscillation of the suction valve is prevented, eliminating suction pulsation and evaporator resonance.

[Example] An example embodying the present invention will be described below with reference to FIGS. 1 and 2. In the apparatus of this embodiment, the structure of the valve plate 9 is different from that of the conventional apparatus, but the structure of other parts is the same, and the same parts are given the same reference numerals and the explanation thereof will be omitted.

A plurality of suction holes 10 and discharge holes 11 (only some of which are shown) are formed in the iron valve plate 9 at positions corresponding to the cylinder bores 2. The valve plate 9 is formed so that its surface has a surface roughness of 1 to 2 Rz, and the surface roughness is formed at the portion around the suction chamber 6 side of the suction hole 10 that contacts the tip seal portion 12a of the suction valve 12. A ring-shaped rough surface portion A is formed so that the roughness is 15Rz.

Note that a bolt insertion hole 17 is formed between each suction hole 10.

Now, as shown by the solid line in FIG. 2, from the open state in which the suction valve 12 is in contact with the valve plate 9 while covering the suction hole 10 of the valve plate 9, the piston 1 is actuated to open the cylinder bore (compression chamber) 2. When the pressure decreases, the refrigerant gas in the suction chamber 6 enters between the suction valve 12 and the valve plate 9 while displacing the lubricating oil present between the two. As a result, the adhesion force of the discharge valve 12 to the valve plate 9 becomes weaker, and the suction valve becomes easier to open.The seal portion 12a of the suction valve 12 is easily separated from the valve plate 9, and the suction hole 10 is opened. In other words, the suction valve 12 quickly separates from the valve grate 9 before it is deflected enough to cause self-excited vibration, unlike the conventional device, and is maintained in the open state shown by the chain line in FIG. 2 without causing automatic vibration. be done. Therefore,
Suction pulsation caused by self-excited vibration of the suction valve 12 is eliminated,
Resonance of the evaporator and generation of abnormal noise due to suction pulsation are prevented.

The rough surface portion A around the suction hole 10 is formed not in the entire portion corresponding to the seal portion 12a of the suction valve 12, but in such a way as to exclude the portion corresponding to the outer periphery of the seal portion 12a. The necessary sealing performance is ensured by the contact between the peripheral edge of the rough surface portion A and the seal portion 12a, and no leakage occurs during the compression stroke.

Noise levels were measured under the following operating conditions when the surface roughness of the rough surface portion A was 12Rz and 21Rz.

Compressor rotation speed...700 ru Suction pressure...2 kg/cJ Discharge pressure ・
・・3 kg/cjl As a result, surface roughness 12 R7
, the noise level was reduced by 2 dB (decibel), and when the surface roughness was 21Rz, it was reduced by 5 dB.

Note that the present invention is not limited to the above embodiments,
For example, the surface roughness of the valve plate 9 may be set to around 6Rz as in the conventional one, or the shape of the rough surface portion A may not be annular with a uniform width, but may vary in width depending on the portion. Furthermore, if the compressor performs compression by the reciprocating movement of the piston, it is not limited to the wobble type compressor.
It may also be applied to other compressors such as s.

[Effects of the Invention] As described in detail below, according to the present invention, when the suction valve is opened, the adhesion force of the suction valve to the valve plate is weakened and the suction valve is opened quickly. No vibration occurs, suction pulsation and resonance of the evaporator are eliminated, and the generation of abnormal noise associated with it is prevented. Further, even when the variable displacement compressor is operating at a small capacity, the suction valve is smoothly opened and closed, and a predetermined amount of refrigerant gas is reliably sucked into the compression chamber. In addition, the surface roughness of the area corresponding to the outer circumference of the suction valve is small, so
The required sealing performance of the suction valve is ensured.

[Brief explanation of drawings]

1 and 2 show an embodiment embodying the present invention, in which FIG. 1 is a sectional view taken along line I-I in FIG. 2, FIG. 2 is a sectional view of main parts, and FIG. FIG. 4 is a cross-sectional view of the wobble-type compacting machine, and is a cross-sectional view of the main part of the conventional device showing the middle of the suction stroke. Piston 1, cylinder bore 2, cylinder block 3, suction chamber 6, rear housing 8, valve plate 9, suction hole 10, suction valve 12, seal portion 12a, rough surface portion A.

Claims (1)

[Claims] 1. In a reciprocating compressor that performs compression by reciprocating movement of a piston housed in a cylinder block, the part corresponding to the suction valve around the suction side of the suction hole formed in the valve plate interposed between the cylinder block and the housing. The suction valve mechanism of a reciprocating compressor has a surface rougher than other parts.