KR101261136B1 - compressor - Google Patents

Abstract

The present invention relates to a compressor that can greatly improve the compression efficiency by minimizing the dead space during refrigerant compression and preventing an increase in discharge resistance. In the present invention, the piston protrusion 131 has a substantially truncated conical shape, the outer surface of which is concave, and the curve C passing through the first, second and third reference points S, T, and U is the piston 30. It is a rotating body formed when rotated about the central axis (L) of. The first, second and third reference points S, T, and U are defined in detail in the detailed description. According to the present invention, the ratio of the reduction in the cross-sectional area of the discharge passage is smaller than the decrease rate of the dead volume during refrigerant compression, thereby securing the discharge passage while reducing the dead volume, thereby improving the cooling performance of the compressor. .

Description

Compressor

The present invention relates to a compressor, and more particularly, to a compressor that can significantly improve the compression efficiency by minimizing the dead space during refrigerant compression and preventing an increase in the refrigerant discharge resistance.

The compressor used in the automobile air conditioning system sucks the evaporated refrigerant from the evaporator and transfers it to the condenser at a high temperature and high pressure state which is easy to be liquefied.

Such a compressor includes a reciprocating type for compressing a refrigerant and a reciprocating type for performing compression while the piston and the like reciprocate, and a rotary type for performing compression while the scroll and the like rotate. The reciprocating type includes a crank type for transmitting a driving force of a driving source to a plurality of pistons using a crank, a swash plate type for transferring a rotating shaft provided with a swash plate, and a wobble plate type using a wobble plate. Rotary types include rotary rotary axes with vane rotary vanes, scrolling with rotary scrolls and fixed scrolls.

1 shows a configuration of a general swash plate compressor in cross section. As shown in the figure, the skeleton and appearance of the compressor 10 are formed by the front head 11, the front cylinder block 12 and the rear cylinder block 12 ′, and the rear head 13. These are arranged in the order of the front head 11, the front cylinder block 12, the rear cylinder block 12 'and the rear head 13 in this order.

The front head 11 has a substantially cylindrical shape and has a discharge chamber 11a formed therein. The discharge chambers 11a are opened toward the front cylinder block 12, respectively. The discharge chamber 11a is formed over a substantially ring-shaped region. The discharge chamber 11a is formed to be selectively connected to each cylinder bore 12a of the front cylinder block 12 through a valve assembly 20 to be described below.

The front head 11 penetrates through the center of the shaft hole (O) is formed. The shaft hole (O) is installed through the rotating shaft 14 to be described below.

The front cylinder block 12 and the rear cylinder block 12 'are coupled to the front head 11 and the rear head 13, respectively. A plurality of cylindrical cylinder bores 12a are formed in the front cylinder block 12 and the rear cylinder block 12 'in the direction of forming the shaft support hole 15 with the shaft support hole 15 as the center. . Of course, the cylinder bore 12a is formed at a position corresponding to the front cylinder block 12 and the rear cylinder block 12 ', respectively. The cylinder bore 12a and the shaft support hole 15 are connected to each other through a suction passage 15 ', respectively. The suction passage 15 ′ allows the refrigerant delivered through the inside of the rotating shaft 14 to be transferred to the cylinder bores 12a, respectively.

Discharge passages (not shown) are formed in the front cylinder block 12 and the rear cylinder block 12 ′ so as to communicate with the discharge chambers 11a and 13a of the front head 11 and the rear head 13, respectively. The discharge passage serves as a passage for discharging the refrigerant compressed in the cylinder bore 12a to the outside.

Refrigerant flow between the front head 11 and the front cylinder block 12 and between the discharge head 11a or 13a and the cylinder bore 12a between the rear head 13 and the rear cylinder block 12 '. The valve assembly 20 for controlling the is provided. That is, the valve assembly 20 controls the refrigerant flow from the cylinder bore 12a to the discharge chamber 11a or 13a.

The valve assembly 20 is provided with a valve plate 21. The valve plate 21 is formed in a substantially disk shape, and the valve plate 21 is formed with a discharge hole 21 'at a position corresponding to each cylinder bore 12a.

A discharge valve 22 is provided on one surface of the valve plate 21 facing the front head 11 and one surface of the valve plate 21 facing the rear head 13. The discharge valve 22 is a material capable of elastic deformation and elastically deforms according to the internal pressure of the cylinder bore 12a to open and close the discharge hole 21 '.

A communication hole (not shown) is formed at a position corresponding to the discharge passage of the valve plate 21. The communication hole serves to connect with the discharge passage.

The front cylinder block 12 and the rear cylinder block 12 'is formed with a recessed portion formed on the surface coupled to each other to form a swash plate chamber (16). In the swash plate chamber 16, the swash plate 17 provided on the rotation shaft 14 is rotatably positioned.

A rotating shaft 14 is installed through the center of the front head 11, the front cylinder block 12 and the rear cylinder block 12 '. The flow passage 14 ′ through which the refrigerant flows is formed in the rotation shaft 14. The flow passage 14 ′ is elongated in the longitudinal direction of the rotation shaft 14 inside the rotation shaft 14. An inlet 14a and an outlet 14b are formed on the outer surface of the rotation shaft 14. The inlet 14a connects the swash plate chamber 16 and the flow passage 14 ', and the outlet 14b is the suction passage 15' of the front cylinder block 12 and the rear cylinder block 12 '. It is formed at a position that can be connected to). The position of the outlet 14b should be formed in accordance with the compression order of the refrigerant proceeding in each cylinder bore 12a.

The shaft seal 18 is inserted into one side of the rotating shaft 14 to be in close contact with the inner surface of the shaft through hole (O) of the front head (11). The shaft seal 18 serves to prevent the refrigerant from leaking between the rotating shaft 14 and the shaft through hole (O). The shaft seal 18 is formed of a rubber material capable of elastic deformation.

An approximately disk-shaped swash plate 17 is inclined with respect to the extending direction of the rotating shaft 14 on the rotating shaft 14. A plurality of shoes 19 surrounding the edge of the swash plate 17 is installed. The shoe 19 is configured to move along the edge of the swash plate 17.

On the other hand, a piston 30 is installed in the cylinder bore 12a so as to reciprocate linearly. The piston 30 has a substantially cylindrical shape corresponding to the inside of the cylinder bore 12a, and both ends thereof are located in the cylinder bore 12a of the front cylinder block 12 and the rear cylinder block 12 ', respectively. That is, both ends of each of the pistons 30 serve to compress the refrigerant in the cylinder bore 12a. The piston 30 is the middle portion thereof is coupled to the shoe 19, the linear reciprocating motion in accordance with the rotation of the swash plate 17.

Meanwhile, as the piston 30 reciprocates, a piston protrusion 31 formed to be selectively inserted into the discharge hole 21 ′ protrudes from the piston 30 on the close contact surface in close contact with the valve plate 21. Is formed. When the piston 30 reciprocates, the piston 30 is in contact with the valve plate 21 and cannot proceed any further, resulting in a cylindrical body formed by the discharge hole 21 ′. The piston protrusion 31 is formed to improve the compression performance of the compressor by reducing such a dead volume.

Meanwhile, the rear head 13 is mounted on one surface of the rear cylinder block 12 '. The discharge chamber 13a is formed in the rear head 13. The discharge chamber 13a is formed over a substantially ring-shaped area. The discharge chamber 13a is opened toward the rear cylinder block 12 ', respectively. The discharge chamber 13a is selectively connected to the cylinder bores 12a formed in the rear cylinder block 12 'through the valve plate 21.

Pulley 40 is rotatably installed on one side of the front head (11). The pulley 40 is formed in a substantially cylindrical shape. The pulley 40 is rotated by receiving the driving force of the engine through a belt (not shown).

The field coil 41 is built in the pulley 40. The field coil 41 generates suction magnetic flux when the power is applied to allow the disk 46 to be described below to closely adhere to the friction surface 40 ′ of the pulley 40.

Meanwhile, a hub 43 is installed at one end of the rotary shaft 14, and a damper 44 is provided at the hub 43. The damper 44 absorbs the shock generated during power transmission between the rotary shaft 14 and the pulley 40. The damper 44 is provided to move the disk 46 in a position facing the friction surface 40 ′ of the pulley 40.

The operation of the compressor having such a structure will be described. When the driving force of the engine is transmitted to the pulley 40 through the belt, the pulley 40 is rotated. However, if power is not applied to the field coil 41, the disk 46 is not in close contact with the friction surface 40 'of the pulley 40, so that the rotation shaft 14 does not rotate.

In this state, when the necessity of operation of the air conditioning system occurs and the compressor needs to be driven, the control system of the user or the vehicle provides a signal for the operation of the air conditioning system. When the operation of the air conditioning system is started and the refrigerant needs to be compressed, the field coil 41 generates suction magnetic flux while power is applied to the field coil 41.

When power is applied to the field coil 41, the disk 46 is in close contact with the friction surface 40 ′ of the pulley 40 by the suction magnetic flux of the field coil 41. Accordingly, the rotational force of the pulley 40 is transmitted to the rotation shaft 14 through the disk 46, the damper 44, and the hub 43.

When the rotational force of the pulley 40 is transmitted to the rotation shaft 14 as described above, the rotation shaft 14 rotates to linearly reciprocate the piston to compress the refrigerant.

At this time, as the rotary shaft 14 rotates, the flow passage 14 'inside the rotary shaft 14 is connected to the cylinder bore 12a through the outlet 14b and the suction passage 15'. The connection between the flow passage 14 ′ and the cylinder bore 12a allows the refrigerant sucked into the swash plate chamber 16 to be transferred to the cylinder bore 12a. For reference, the refrigerant is sucked into the cylinder bore 12a when the piston 30 is located at the bottom dead center of the corresponding cylinder bore 12a. As such, when the refrigerant is delivered to the cylinder bore 12a, the piston 30 of the corresponding cylinder bore 12a moves in the direction of the valve plate 21, and compression of the refrigerant occurs.

Thus, when the refrigerant is compressed in the cylinder bore 12a, the pressure inside the cylinder bore 12a becomes relatively high, and the refrigerant is discharged to the discharge chambers 11a and 13a. The refrigerant discharged into the discharge chambers 11a and 13a is transferred to a condenser (not shown) through an external discharge port.

The refrigerant delivered to the condenser through the discharge port is delivered to the compressor again through a condenser (not shown), an expansion valve (not shown), and an evaporator (not shown). In the compressor the refrigerant is compressed by repeating the process described above.

At this time, the piston protrusion 31 is formed to improve the compression performance of the compressor by reducing the dead volume as already described. However, the coolant discharge resistance is increased by narrowing the coolant discharge flow path from the cylinder bore 12a to the discharge chambers 11a and 13a by the formation of the piston protrusion 31 when the compressor 10 is driven as described above. Compressor performance improvement due to the reduction of the dead volume has been minimal.

Accordingly, in order to improve the performance of the compressor by reducing the dead volume during refrigerant compression by forming the piston protrusion 31, the shape of the piston protrusion 31 which can minimize the refrigerant discharge resistance during refrigerant discharge and the discharge hole for accommodating the same ( 21 ') it is important to design the shape precisely.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, to provide a compressor that improves the refrigerant compression efficiency of the compressor by reducing the dead volume during refrigerant compression in the compressor and at the same time prevent the increase in discharge resistance will be.

Another object of the present invention is to provide a compressor having improved cooling performance of the compressor by securing a discharge flow path while reducing the dead volume during refrigerant compression in the compressor.

According to a feature of the present invention for achieving the above object, the present invention is a cylinder block formed with a plurality of cylinder bores therein, and the discharge chamber is coupled to the cylinder block in communication with the cylinder bore is formed A rear plate, a valve plate 21 having a discharge hole 21 'communicating with the cylinder bore and the discharge chamber, and a piston protrusion selectively inserted into the discharge hole 21' according to a linear reciprocating motion. 131 is integrally formed to protrude and includes a piston 30 for compressing the refrigerant by linearly reciprocating in the cylinder bore, the discharge hole 21 ′ penetrates vertically through the valve plate 21. It consists of a part 21b and the taper part 21a which forms the inclined surface from the valve plate 21 to the said through part 21b, The said piston protrusion 131 is the said piston 30 from the said piston 30. Virtual base portion 31a which protrudes in parallel to the direction of motion of the circumference and has a diameter which decreases with a constant slope as the cross section perpendicular to the direction of motion of the piston 30 moves away from the piston 30, As the cross section perpendicular to the direction of movement of the piston 30 moves away from the virtual base portion 31a, the diameter of the cross section of the virtual base portion 31a decreases with a constant slope smaller than a slope that decreases. And a virtual protrusion 31b, wherein the piston protrusion 131 has a curve C passing through the first, second, and third reference points S, T, and U, the center axis of the piston 30. L is a rotating body formed when rotated around the first reference point (S) is the point where the outer surface of the virtual base portion 31a and the front end of the piston 30, the second reference point (T) is Between the straight line passing through the first and third reference points (S, U) and the central axis (L) The third reference point (U) is a point that is present at the tip of the protrusion (31b), and the first, second and third reference point (S, T, U) on the same plane The virtual base portion 31a and the virtual protrusion portion 31b for deriving the first, second and third reference points S, T, and U are defined as follows. .

[next]

)는 1.5 이상 3 이하의 범위 내로 한정되며, 상기 밸브플레이트(21)의 수직방향과 상기 테이퍼부(21a)의 경사면이 이루는 각과 상기 가상의 기저부(21a)의 경사면이 상기 피스톤(30)의 운동방향과 이루는 각 사이의 차(

)는 -10 이상 10 이하의 범위 내임.The ratio R _{A of the} cross-sectional area of the piston 30 perpendicular to the direction of movement of the piston 30 and the maximum cross-sectional area of the virtual base portion 31a is limited within the range of 0.4 or more and 0.5 or less. The ratio between the angle at which the inclined surface of the protrusion 31b forms the movement direction of the piston 30 and the angle at which the inclined surface of the virtual base portion 31a forms the movement direction of the piston 30 (

) Is limited to the range of 1.5 or more and 3 or less, and the angle between the vertical direction of the valve plate 21 and the inclined surface of the tapered portion 21a and the inclined surface of the virtual base portion 21a are the movement of the piston 30. The difference between the direction and the angle

) Ranges from -10 to 10.

In addition, the second reference point T may be a point where the outer surface of the base portion 31a and the protrusion 31b meet.

And the curve (C) is characterized in that the circular arc having a constant radius of curvature.

According to the compressor according to the present invention, the following effects can be obtained.

That is, the compressor according to the present invention has the advantage that the refrigerant compression efficiency of the compressor is improved by reducing the dead volume during refrigerant compression in the compressor and preventing the discharge resistance from increasing.

In addition, the compressor according to the present invention ensures the discharge passage while reducing the dead volume by decreasing the cross-sectional area reduction ratio of the discharge passage to the reduction rate of the dead volume during refrigerant compression. As a result, the refrigerant may be discharged more smoothly, thereby improving the cooling performance of the compressor.

1 is a cross-sectional view showing the configuration of a typical rotary suction (Rotary Suction) compressor.
Figure 2a is a perspective view showing the protrusion shape of the compressor piston according to the first embodiment of the present invention.
FIG. 2B is a cross-sectional view showing the cross-sectional shape of the compressor piston shown in FIG. 2A; FIG.
Figure 3a is a perspective view showing the shape of the compressor valve plate according to the first embodiment of the present invention.
3B is a cross-sectional view showing a cross-sectional shape of the discharge hole of the compressor valve plate shown in FIG. 3A.
4 is a graph showing a change in compressor performance according to the first embodiment of the present invention.
5 is a partial cross-sectional view showing the insertion process of the piston projection of the compressor into the discharge hole according to the first embodiment of the present invention.
6 is a cross-sectional view showing a cross-sectional shape of a compressor piston according to a second embodiment of the present invention.
7 is a graph for comparing the cross-sectional area reduction rate of the discharge flow path of the first embodiment and the second embodiment in the present invention.

Hereinafter, a first embodiment of a compressor according to the present invention will be described in detail with reference to the accompanying drawings. In particular, hereinafter, the main part of the present invention will be described, and other components of the compressor are similar to those described in the background art, and thus the description thereof will be omitted below. The same or similar configuration as the compressor described in the background will be described using the same reference numerals.

Figure 2a is a perspective view showing the projection shape of the compressor piston according to the first embodiment of the present invention, Figure 2b is a cross-sectional view showing a cross-sectional shape of the compressor piston shown in Figure 2a, Figure 3a is a first embodiment of the present invention 3 is a perspective view showing the shape of the compressor valve plate according to the embodiment, and FIG. 3B is a cross-sectional view showing the cross-sectional shape of the discharge hole of the compressor valve plate shown in FIG. 3A. 4 is a graph showing a change in compressor performance according to the first embodiment of the present invention.

First, the piston protrusion 31 of the compressor 10 according to the first embodiment of the present invention will be described in more detail with the protrusion shape of the compressor piston according to the first embodiment of the present invention. Protrudes parallel from the piston 30 in a reciprocating linear motion direction. In addition, the piston protrusion 31 has a circular cross section perpendicular to the direction of movement of the piston 30.

를 이루는 기저부(31a)와 상기 피스톤(30)의 운동 방향과 각

을 이루는 돌출부(31b)로 구성된다. 즉, 상기 기저부(31a)와 상기 돌출부(31b)는 선단으로 향할수록 상기 피스톤(30)의 운동 방향에 수직인 원형의 단면의 직경이 점차 작아지도록 형성된다. 여기서 각

는 각

보다 큰 값을 갖는다. 또한 상기 피스톤돌기(31)는 상기 피스톤(30)으로부터 전체적으로 높이 H₁을 갖도록 형성되며, 상기 기저부(31a)는 높이 h₁을 갖는다. 따라서 상기 돌출부(31b)만의 높이는 (H₁-h₁)이 된다. The piston protrusion 31 is formed integrally with the piston 30, and is formed to be inclined in two stages, the movement direction and the angle of the piston 30

Movement direction and angle of the base portion 31a and the piston 30 forming a

Consists of a protrusion (31b) forming a. That is, the base portion 31a and the protrusion portion 31b are formed such that the diameter of the circular cross section perpendicular to the direction of movement of the piston 30 gradually decreases toward the tip. Where each

Is each

Has a greater value. In addition, the piston protrusion 31 is formed to have a height H ₁ as a whole from the piston 30, the base portion 31a has a height h ₁ . Therefore, the height of only the protrusion part 31b becomes (H ₁ -h ₁ ).

In addition, when the diameter of the piston 30 in the cross section perpendicular to the direction of movement of the piston 30 is D, the base portion 31a has a diameter that is constantly reduced from the maximum diameter d ₁ to the minimum diameter d ₂ , The protrusion 31b has a diameter that constantly decreases from the maximum diameter d ₂ to the minimum diameter d ₃ of its tip.

Meanwhile, as shown in FIGS. 3A and 3B, the discharge hole 21 ′ of the valve plate 21 selectively accommodates the piston protrusion 31 according to the forward and backward reciprocating motion of the piston 30. A through portion 21b penetrating the plate 21 vertically and a tapered portion 21a forming an inclined surface from the valve plate 21 to the through portion 21b.

를 이룸으로써 도면에 도시된 바와 같이 상기 관통부(21b)를 향할수록 일정하게 감소하는 직경을 갖는다. 반면 상기 관통부(21b)는 상기 밸브플레이트의 수직 방향과 평행한 면으로 이루어짐으로써 그 직경이 d₄로 일정하다. 여기서 상기 밸브플레이트의 높이를 H₂, 상기 관통부의 높이를 h₂로 한다. The inclined surface by the tapered portion 21a is perpendicular to the vertical direction of the valve plate.

As shown in the figure, as shown in the figure, the diameter decreases constantly toward the through part 21b. On the other hand, since the through part 21b is made of a surface parallel to the vertical direction of the valve plate, its diameter is constant as d ₄ . Here, the height of the valve plate is H ₂ , and the height of the through part is h ₂ .

In order to more specifically limit the shapes of the piston protrusion 31 and the discharge hole 21 'to reduce the dead volume during refrigerant compression and to prevent the discharge resistance from increasing, the following equations Define the argument by

는 상기 피스톤(30)의 압축 방향 단면적의 넓이

와 상기 피스톤돌기(31)의 최대 직경에 의한 상기 피스톤돌기(31)의 최대 단면적의 넓이

사이의 비율을 정의한 것이고, 수학식 2에 나타낸 인자

는 상기 기저부(31a)가 상기 피스톤(30)의 운동 방향과 이루는 경사각

와 상기 돌출부(31b)가 상기 피스톤(30)의 운동 방향과 이루는 경사각

사이의 비율을 하나의 독립된 인자로 정의한 것이다. Where the factor shown in equation (1)

Is the width of the cross-sectional area in the compression direction of the piston (30)

And the width of the largest cross-sectional area of the piston protrusion 31 by the maximum diameter of the piston protrusion 31.

The ratio between

Is the inclination angle of the base portion 31a and the direction of movement of the piston 30

And the inclination angle between the protrusion 31b and the movement direction of the piston 30

The ratio between is defined as an independent factor.

는 상기 밸브플레이트(21)의 상기 테이퍼부(21a)가 상기 밸브플레이트(31)의 수직 방향, 즉 상기 피스톤(30)의 운동방향과 이루는 각

과 상기 피스톤돌기(31)의 상기 기저부(31a)와 상기 피스톤(30)의 운동방향이 이루는 각

사이의 차를 하나의 인자로 정의한 것이다. And the factor shown in Equation 3 above.

Is an angle between the tapered portion 21a of the valve plate 21 and the vertical direction of the valve plate 31, that is, the movement direction of the piston 30.

And an angle formed between the base portion 31a of the piston protrusion 31 and the movement direction of the piston 30.

The difference between the two is defined as a factor.

All of these defined factors are ratios or differences between specific values, which makes them applicable to various types or sizes of compressor piston protrusions and discharge holes.

With respect to the factors defined as above, the embodiment of the present invention limits the range of the above factors that can maximize the performance of the compressor 10.

The graph shown in FIG. 4 shows the relationship between the values of the three factors defined above, the volumetric efficiency (%) and the compressor coefficient of efficiency (COP) of the compressor.

는 대략 0.41의 값 부분에서 최대 체적 효율과 최대 성능 계수를 나타낸다. 그리고

는 -10에서 10도가 넘지 않는 범위 내에서 선택되는 것이 유리하다.As you can see in the graph

Represents the maximum volumetric efficiency and the maximum coefficient of performance in the value portion of approximately 0.41. And

Is advantageously selected within the range of -10 to no more than 10 degrees.

는 대략 2.5를 넘어서는 부분에서 높은 효율을 보임을 확인할 수 있다.Also

It can be seen that the high efficiency is shown in the portion exceeding approximately 2.5.

Based on these results, the numerical range of each of the above factors is limited as follows.

≤ 0.50.4 ≤

≤ 0.5

≤ 31.5 ≤

≤ 3

≤ 10
-10 ≤

≤ 10

In addition, the following parameters can be further defined.

The factor G _h represented by Equation 4 may be defined as a height difference between the height of the tapered portion 21a of the valve plate 21 and the protrusion 31b of the piston protrusion 31. Such G _h is helpful for compressor performance when it is adjusted within the range of 0 to 0.15.

Further, even when the piston protrusions 31 are formed, the piston protrusions 31 are accommodated in the discharge holes 21 ′ in order to prevent an increase in the refrigerant discharge resistance when the compressor 10 compresses the refrigerant. The minimum discharge effective diameter in the step is the width of the discharge flow path formed between the valve plate 21 and the discharge valve 22 when the discharge valve 22 is fully opened (hereinafter referred to as discharge effective diameter D _ed ). It is preferable to become above.

Here, the step in which the piston protrusion 31 is accommodated as the discharge hole 21 ′ may be divided into three stages as shown in FIG. 5, and the minimum discharge effective diameter is the piston in each stage shown in FIG. The narrowest cross-sectional area of the refrigerant discharge flow path formed between the projection 31 and the discharge hole 21 'is defined as a numerical value.

First, step (a) shown on the left side of FIG. 5 illustrates a step in which the tip of the piston protrusion 31 starts to enter the tapered portion 21a of the discharge hole 21 '.

Accordingly, the step (a) the minimum discharge effective diameter (D _e1) in the following is calculated by the following equation.

The minimum discharge effective diameter (D _e1) at the step (a) as identified in the equation (5) becomes a value obtained by subtracting the minimum cross-sectional area of the projecting portion (31b) at the maximum cross-sectional area of the tapered portion (21a).

In addition, the minimum ejection effective diameter D _e2 in step (b) illustrated in FIG. 5 is calculated as follows.

As confirmed in Equation 6, in step (b), the D _e2 is the minimum diameter d of the protrusion part 31b of the piston protrusion 31 in the cross-sectional area of the through part 21b of the valve plate 21. It becomes the value which subtracted the minimum cross-sectional area by ₃ .

Furthermore, the discharge minimum effective diameter (D _e3) in the step (c) shown in Figure 5 are the following operations in the same way.

As confirmed in Equation (7), in the step (c), D _e3 is the maximum diameter d of the protrusion part 31b of the piston protrusion 31 in the cross-sectional area of the through part 21b of the valve plate 21. It becomes the value which subtracted the maximum cross-sectional area by ₂ .

In three stages in which the piston protrusion 31 is accommodated in the discharge hole 21 ′, values of the three minimum discharge effective diameters calculated as described above are formed between the valve plate 21 and the discharge valve 22. It is preferable to be more than the discharge effective diameter D _ed .

Next, a detailed configuration of the second embodiment of the present invention will be described with reference to the accompanying drawings. In particular, the following description mainly focuses on the main part of the second embodiment of the present invention, and detailed description of the same configuration as that of the first embodiment and the background art is omitted.

6 is a cross-sectional view of the projection shape of the compressor piston according to the second embodiment of the present invention, Figure 7 is a graph for comparing the cross-sectional area reduction rate of the discharge flow path of the first embodiment and the second embodiment in the present invention Is shown.

As shown in FIG. 6, the piston protrusion 131 is formed to protrude from the tip of the piston 30. First, in the second embodiment of the present invention, the shape of the piston protrusion 131 will be described based on FIG. 6. The piston protrusion 131 passes through the first, second, and third reference points S, T, and U. Curve (C) is a rotating body formed when rotated about the central axis (L) of the piston (30). That is, the piston protrusion 131 is formed in a substantially truncated conical shape, the outer surface of which is concave.

The three reference points S, T, and U are defined by factors for forming the base portion 31a and the protrusion 31b of the first embodiment described above. For reference, in FIG. 6, the base portion 31a and the protrusion portion 31b of the first embodiment are indicated by dotted lines.

First, the first reference point S is a point where the outer surface of the base portion 31a and the tip of the piston 30 meet with reference to FIG. 6.

And the second reference point (T) is defined as any one point between the straight line passing through the first reference point (S) and the third reference point (U) and the central axis (L). In this case, the second reference point T is preferably determined as a point where the outer surface of the base portion 31a and the protrusion 31b meet.

Finally, the third reference point U is a point that becomes the tip of the protrusion 31b. It is natural that the three reference points S, T, and U are coplanar with respect to FIG. 6.

As such, when the first, second and third reference points S, T, and U are set by the factors described in the first embodiment, the curve C passing through these three reference points S, T, and U is set. This may be made, the piston protrusion 131 of the second embodiment of the present invention may be defined as a rotating body formed by rotating the curve (C) based on the central axis (L) of FIG.

In this case, the curve C may be an arc having a constant radius of curvature.

Next, effects according to the shape of the piston protrusion 131 according to the second embodiment of the present invention will be described with reference to FIG.

When the refrigerant is compressed, the piston moves forward toward the valve plate, and the X axis of the graph shown in FIG. 7 represents the forward movement distance of the piston. 7 is a graph measuring the rate of reduction of the cross-sectional area of the discharge passage according to the forward movement distance of the piston, showing a comparison between the first embodiment and the second embodiment of the present invention. For reference, the volume reduction rate in the graph of Figure 7 shows the volume reduction rate of the cylinder bore according to the forward movement of the piston.

As can be seen from the graph of Fig. 7, there is a section in which the discharge flow path cross-sectional area reduction rate (graph slope) in the second embodiment is smaller than in the first embodiment. The small rate of reduction in the cross-sectional area of the discharge passage during the forward movement of the piston for compressing the refrigerant means that the discharge passage can be more easily secured.

That is, according to the second embodiment of the present invention, the ratio of the reduction in the cross-sectional area of the discharge passage to the reduction rate of the dead volume during refrigerant compression is reduced, thereby ensuring the discharge passage while reducing the dead volume. As a result, the refrigerant is discharged more smoothly, thereby improving the cooling performance of the compressor.

For reference, Claim 1 defines the second embodiment of the present invention as a claim, the first embodiment to derive the first, second and third reference point (S, T, U) of the second embodiment of the present invention Since the concept of the base portion 31a and the protrusion 31b described in FIG. 1 is borrowed, the terms of the virtual base portion 31a and the virtual protrusion 31b are used in claim 1.

The scope of the present invention is not limited to the embodiments described above, but may be defined by the scope of the claims, and those skilled in the art may make various modifications and alterations within the scope of the claims It is self-evident.

For example, the piston protrusion of the present invention may be formed on a piston installed in a variable displacement swash plate compressor. That is, the variable displacement swash plate compressor includes a cylinder block having a plurality of cylinder bores, a piston installed in the cylinder bore to compress the working fluid by linear reciprocating motion, and a crank chamber coupled to the front of the cylinder block. A front head to be formed, a rear head coupled to the rear of the cylinder block to form a suction chamber and a discharge chamber therein, a drive shaft rotatably supported by the cylinder block, and coupled to the drive shaft in the crank chamber together. And a valve plate having a swash plate which is rotated and transmits power to the piston, and a discharge hole communicating with the cylinder bore and the discharge chamber, wherein the piston protrusion of the present invention may be integrally formed on the piston.

10: Compressor 11: Fronthead
11a: discharge chamber 12: front cylinder block
12 ': rear cylinder block 12a: cylinder bore
13: rear head 14: axis of rotation
14a: entrance 14b: exit
15: shaft supporter 15 ': suction passage
16: Judge Room 17: Judge
18: Holiday 19: Shoe
20: valve assembly 21: valve plate
21 ': discharge hole 21a: tapered portion
21b: through part 22: discharge valve
30: piston 31, 131: piston protrusion
31a: base 31b: protrusion
40 ': Friction surface 41: Field coil
43: hub 44: damper
46: disks S, T, U: first, second and third reference points

Claims (3)

A cylinder block having a plurality of cylinder bores formed therein, a rear head coupled to the cylinder block to form a discharge chamber communicating with the cylinder bore therein, and a discharge hole communicating with the cylinder bore and the discharge chamber 21 ') Formed valve plate 21 and the piston protrusion 131 selectively inserted into the discharge hole 21' according to the linear reciprocating motion is integrally formed and linear reciprocating motion in the cylinder bore to cool the refrigerant It includes a piston 30 for compressing,
The discharge hole 21 'includes a through portion 21b penetrating the valve plate 21 vertically and a tapered portion 21a forming an inclined surface from the valve plate 21 to the through portion 21b. Lose,
The piston protrusion 131 protrudes in parallel to the direction of movement of the piston 30 from the piston 30, and as the cross section perpendicular to the direction of movement of the piston 30 moves away from the piston 30. The virtual base portion 31a formed to have a diameter decreasing with a constant slope, and the cross section perpendicular to the direction of movement of the piston 30 moves away from the virtual base portion 31a of the virtual base portion 31a. An imaginary protrusion 31b formed to have a diameter that decreases at a constant slope smaller than the slope at which the diameter of the cross section is reduced,
The piston protrusion 131 is formed when the curve (C) passing through the first, second and third reference point (S, T, U) is rotated about the central axis (L) of the piston 30 Is full,
The first reference point S is a point where the outer surface of the virtual base portion 31a and the tip of the piston 30 meet, and the second reference point T passes through the first and third reference points S and U. It is an arbitrary point which exists between a straight line and the said central axis L, The said 3rd reference point U is a point used as the front-end | tip of the said projection part 31b, The said 1st, 2nd and 3rd reference point S , T, U) are coplanar,
And the virtual base portion (31a) and the virtual protrusion portion (31b) for deriving the first, second and third reference points (S, T, U) are defined as follows.
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The ratio R _{A of the} cross-sectional area of the piston 30 perpendicular to the direction of movement of the piston 30 and the maximum cross-sectional area of the virtual base portion 31a is limited within the range of 0.4 or more and 0.5 or less. The ratio between the angle at which the inclined surface of the protrusion 31b forms the movement direction of the piston 30 and the angle at which the inclined surface of the virtual base portion 31a forms the movement direction of the piston 30 (

) Is limited to the range of 1.5 or more and 3 or less, and the angle formed between the vertical direction of the valve plate 21 and the inclined surface of the tapered portion 21a and the inclined surface of the virtual base portion 21a are the movement of the piston 30. The difference between the direction and the angle

) Ranges from -10 to 10. The compressor as claimed in claim 1, wherein the second reference point (T) is a point where the outer surface of the base portion (31a) and the protrusion portion (31b) meet. The compressor as claimed in claim 1 or 2, wherein the curve C is a circular arc having a constant radius of curvature.

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