JP6321400B2 - Hermetic compressor - Google Patents

Description

  The present invention relates to a hermetic compressor mainly used in an electric refrigerator-freezer for home use.

  Conventionally, this type of hermetic compressor is provided with a protrusion on the front end surface of the piston, and when the piston is located at the top dead center, the protrusion enters the discharge hole of the valve plate, and the remaining working fluid remains in the compression chamber. The amount is reduced as much as possible to improve efficiency (for example, see Patent Document 1).

  The conventional hermetic compressor will be described below with reference to the drawings.

  FIG. 19 is a longitudinal sectional view of a conventional hermetic compressor described in Patent Document 1, and FIG. 20 is an enlarged cross-sectional view of a main part of a compression element of the conventional hermetic compressor described in Patent Document 1. .

  19 and 20, the sealed container 1 is provided with a suction pipe 2, stores the lubricating oil 3 at the bottom, and compresses the compressed gas 5 by sucking and compressing refrigerant gas (not shown). A compressor main body 13 composed of an electric element 11 including a rotor 7 and a stator 9 for driving the element 5 is supported and accommodated via an elastic body 15 such as a spring.

  The piston 17 is inserted into a substantially cylindrical cylinder block 19 so as to be slidable back and forth, and is connected to the crank pin 21 by a connecting rod 23 as a connecting means.

  The crank pin 21 is formed eccentric to a crank shaft 25 that is press-fitted and fixed to the rotor 7.

  A valve plate 27 that seals the opening end face of the cylinder block 19 is a discharge valve device that includes a suction port 31 that communicates with the cylinder block 19 by opening and closing the suction valve 29, and a discharge valve 33 and a discharge valve seat 35 shown in FIG. A discharge port 39 communicating with the cylinder block 19 by opening and closing 37 is provided, and a compression chamber 43 is formed.

  A cylinder head 45 forming a high pressure chamber (not shown) is fixed to the opposite side of the cylinder block 19 via a valve plate 27.

  As shown in FIG. 20, the piston 17 includes, on its compression chamber side end surface 41, a truncated cone-shaped projection 47 and a cylindrical projection 49 continuous to the truncated cone-shaped projection 47 in order from the compression chamber side end surface 41. The discharge port 39 of the valve plate 27 has a shape corresponding to the protrusion 51 of the piston 17.

  The operation and action of the hermetic compressor configured as described above will be described below.

  When the crankshaft 25 is rotationally driven by the rotation of the rotor 7 of the electric element 11, the piston 17 reciprocates in the compression chamber 43 of the cylinder block 19 through the connecting rod 23 by the eccentric movement of the crankpin 21. Perform the compression operation.

  In the discharge stroke of the piston 17, the compressed refrigerant gas (not shown) in the compression chamber 43 passes through the discharge port 39 and is discharged to the high pressure chamber (not shown) by opening and closing the discharge valve device 37. .

  At this time, the refrigerant gas flow passage cross-sectional area of the discharge port 39 is large at the initial stage of opening and closing of the discharge valve device 37 where the flow rate of the refrigerant gas (not shown) discharged through the discharge port 39 is large. At the end of the decrease, the convex portion 51 formed of the truncated cone-shaped protrusion 47 and the cylindrical protrusion 49 formed in order from the compression chamber side end face 41 of the piston 17 enters the discharge port 39, and therefore the refrigerant gas flow in the discharge port 39 The cross-sectional area of the road gradually decreases, the discharge efficiency of the compressed refrigerant gas is good, and the efficiency of the refrigerant compressor is high.

  That is, at the top dead center of the piston 17, the refrigerant gas remaining in the discharge port 39 is re-expanded in the next intake stroke, so that the amount of refrigerant gas to be sucked is reduced and lost. However, the convex part 51 which consists of the truncated cone-shaped projection part 47 and the cylindrical projection part 49 continuing to the truncated cone-shaped projection part 47 in order from the compression chamber side end face 41 is provided on the compression chamber side end face 41 of the piston 17. Therefore, since the convex portion 51 enters the discharge port 39 and reduces the amount of refrigerant gas remaining in the discharge port 39, the loss due to re-expansion is small and the efficiency of the refrigerant compressor is increased. is there.

JP 2010-90705 A

  However, in the conventional configuration, when the volume of the convex portion 51 is increased and the refrigerant gas remaining in the compression chamber 43 at the top dead center of the piston 17 is further reduced, the tip of the suction valve 29 and the piston 17 are sucked in the suction process. The compression chamber side end face 41 comes into contact with each other, and there is a problem in reliability such that abnormal noise or valve chipping occurs. Further, although the conventional technology can be expected to improve the efficiency of the compressor, there remains some room for improvement, such as disturbance in the flow of the refrigerant gas flowing toward the protrusion.

  The present invention has been made in view of such a point, and an object thereof is to provide a hermetic compressor having high reliability and high efficiency.

  In order to solve the above-described conventional problems, the hermetic compressor according to the present invention has a protrusion provided on a tip surface of the piston facing the valve plate, and the protrusion is located when the piston is located at the top dead center. It is formed so as to be inserted into the discharge hole of the valve plate, and further passes through the position facing the discharge hole from the outer peripheral edge portion of the front end surface to the front end surface of the piston facing the valve plate. A groove having a predetermined width extending toward the position facing the tip is formed.

  Thereby, the refrigerant gas can be efficiently guided to the discharge hole by the groove having a predetermined width while avoiding contact between the tip of the suction valve and the tip surface of the piston when the piston is located at the top dead center. A highly efficient hermetic compressor can be provided while maintaining high reliability.

  The hermetic compressor of the present invention avoids contact between the tip of the suction valve and the tip of the piston at the top dead center position of the piston, improves reliability, and further improves the efficiency of the electric compressor. Can do.

1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention. The exploded perspective view of the compression element of the hermetic compressor in Embodiment 1 The perspective view of the piston of the hermetic compressor in Embodiment 1 The principal part enlarged view of the valve plate of the hermetic compressor in Embodiment 1 (A)-(d) The schematic diagram explaining the operation | movement of the hermetic type compressor in Embodiment 1. FIG. (A)-(d) is a schematic diagram for description of contrast for demonstrating the operation effect of the hermetic compressor in Embodiment 1. FIG. Vertical sectional view of a hermetic compressor according to Embodiment 2 of the present invention The exploded perspective view of the compression element of the hermetic compressor in Embodiment 2 The perspective view of the piston of the hermetic compressor in Embodiment 2 The principal part enlarged view of the valve | bulb plate of the hermetic compressor in Embodiment 2 (A)-(d) The schematic diagram explaining operation | movement of the hermetic type compressor in Embodiment 2. FIG. (A)-(d) is a schematic diagram for description of contrast for demonstrating the operation effect of the hermetic compressor in the second embodiment. Vertical sectional view of a hermetic compressor according to Embodiment 3 of the present invention The exploded perspective view of the compression element of the hermetic compressor in Embodiment 3 The perspective view of the piston of the hermetic compressor in Embodiment 3 The principal part enlarged view of the valve | bulb plate of the hermetic compressor in Embodiment 3 (A)-(d) The schematic diagram explaining operation | movement of the hermetic type compressor in Embodiment 3. (A)-(d) is the schematic diagram for description of contrast for demonstrating the operation effect of the hermetic type compressor in Embodiment 3. Vertical section of a conventional hermetic compressor Expanded sectional view of the main part of the compression element of a conventional hermetic compressor

  A first invention includes an electric element, a compression element driven by the electric element, and a sealed container in which the electric element and the compression element are accommodated, wherein the compression element forms a cylinder block. A piston that reciprocates in the compression chamber, a valve plate that is disposed so as to close an open end of the compression chamber, and that has a suction hole and a discharge hole that communicate with the outside of the compression chamber, and the valve A suction valve that opens and closes the suction hole of the plate, and a protrusion is provided on a front end surface of the piston facing the valve plate, and the protrusion is a valve when the piston is located at a top dead center. The piston is formed so as to be inserted into the discharge hole of the plate, and further, the piston tip surface passes through the position facing the discharge hole of the valve plate from the outer peripheral edge thereof, It is constituted of a groove of a predetermined width extending toward the position facing the lube distal end portion is formed.

  Accordingly, during the compression stroke in which the piston operates from the bottom dead center to the top dead center, the working fluid located near the inner peripheral surface of the compression chamber (outer peripheral edge portion of the piston tip surface) away from the discharge hole Thus, it is possible to guide to the position facing the discharge hole on the tip surface of the piston, and to efficiently guide to the discharge hole by the tip portion of the groove.

  Further, during the suction stroke in which the piston moves from top dead center to bottom dead center, even if the tip of the suction valve and the tip surface of the piston approach, the tip of the suction valve and the tip surface of the piston are Contact can be avoided, and it can be made highly reliable without causing abnormal noise or valve chipping.

In the second invention, in particular, the groove having a predetermined width on the tip surface of the piston according to the first invention is configured such that the central axis thereof passes through the center point of the piston, thereby providing a highly efficient hermetic compressor. be able to.

  In the third invention, in particular, the piston of the first invention has a trapezoidal shape in which the width of the front end surface is narrow, the discharge hole side is narrow, and the suction valve front end side is wide, and the central axis of the trapezoid passes through the center point of the piston. It is configured, and a more efficient hermetic compressor can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 is a longitudinal sectional view of a hermetic compressor according to Embodiment 1 of the present invention, FIG. 2 is an exploded perspective view of a compression element of the hermetic compressor according to Embodiment 1, and FIG. FIG. 4 is a perspective view of a piston of the hermetic compressor in the first embodiment, and FIG. 4 is an enlarged view of a main part of the compression element of the hermetic compressor in the first embodiment. FIGS. 5A to 5D are schematic views for explaining the operation of the hermetic compressor in the first embodiment, and FIGS. 6A to 6D are hermetic compressors in the first embodiment. It is a schematic diagram for description of comparison for demonstrating the operation effect.

  As shown in FIGS. 1 to 3, the sealed container 101 stores oil 103 at the bottom, and further contains a refrigerant as a working fluid 105.

  The sealed container 101 is formed by drawing a steel plate and includes a suction pipe 107 and a discharge pipe 109. The suction pipe 107 is provided so as to penetrate the sealed container 101, and its upstream end is connected to the low pressure side (not shown) of the refrigeration cycle, and its downstream end communicates with the sealed container 101. The discharge pipe 109 is provided so as to penetrate the sealed container 101, and its upstream end communicates with a discharge muffler (not shown), and its downstream end is connected to the high-pressure side (not shown) of the refrigeration cycle. ing.

  In the sealed container 101, a compressor main body 115 including a compression element 111 and an electric element 113 that drives the compression element 111 is housed. The compressor main body 115 is elastically supported with respect to the closed casing 101 by a suspension spring 117.

  The compression element 111 includes a crankshaft 119, a cylinder block 121, a piston 123, a connecting means 125, and the like. The crankshaft 119 includes a main shaft 127 and an eccentric shaft 129.

  The electric element 113 is composed of a stator 131 fixed by bolts (not shown) below the cylinder block 121 and a rotor 133 disposed inside the stator 131 and shrink-fitted to the main shaft 127 and fixed. .

  The cylinder block 121 is integrally formed with a cylinder 137 that forms the compression chamber 135 and a bearing portion 139 that rotatably supports the main shaft 127.

  In addition, as shown in FIG. 2, the suction valve 141, the valve plate 143, and the cylinder head 145 are arranged in this order on the end surface of the cylinder 137, and the end surface of the cylinder 137 is sealed by the head bolt 147. To be fixed. The valve plate 143 is provided with a suction hole 149 and a discharge hole 151 that communicate between the inside and outside of the compression chamber 135. The suction valve 141 is configured to open and close the suction hole 149. The cylinder head 145 is configured to cover the valve plate 143.

  A discharge valve 153 that opens and closes the discharge hole 151 is fixed to a surface of the valve plate 143 that faces the cylinder head 145. A head space 155 is formed by the valve plate 143 and the cylinder head 145. Further, as shown in FIG. 1, a suction muffler 157 is gripped and fixed between the valve plate 143 and the cylinder head 145.

  Further, as shown in FIG. 3, a protrusion 163 is provided on the tip surface 159 of the piston 123 facing the valve plate 143 in the piston 123, and the protrusion 163 is formed when the piston 123 is located at the top dead center. It is formed so as to be inserted into the discharge hole 151 of the valve plate 143. Further, a belt-like (linear) groove 161 is provided on the distal end surface 159. As shown in FIGS. 2 and 3, the groove 161 is provided so as to extend from the position of the distal end surface 159 facing the suction valve tip 141 a of the suction valve 141 toward the position of the distal end surface 159 facing the discharge hole 151. It has been.

  The operation of the hermetic compressor configured as described above will be described below.

  The hermetic compressor causes the crankshaft 119 to rotate by causing a current to flow through the stator 131 to generate a magnetic field and rotating the rotor 133 fixed to the main shaft 127. Along with this, the piston 123 reciprocates in the cylinder 137 through the connecting means 125 rotatably attached to the eccentric shaft 129.

  As the piston 123 reciprocates, the working fluid 105 is sucked into the compression chamber 135 via the suction muffler 157, compressed, and then discharged from the discharge hole 151, through the head space 155 and the discharge pipe 109. It flows into a refrigeration cycle (not shown).

  Next, suction, compression, and discharge strokes of the working fluid 105 by the compressor main body 115 will be described with reference to FIGS.

  FIGS. 5A to 5D are schematic diagrams for explaining the operation of the hermetic compressor in the first embodiment, and FIGS. 6A to 6D are diagrams of the hermetic compressor in the first embodiment. FIG. 4 is a schematic diagram for explaining the operation, in which (a) shows the middle of the suction stroke, (b) shows the end of the suction stroke (near the bottom dead center), and (c) shows the middle of the compression stroke. , (D) show the discharge stroke (near top dead center), respectively.

  In the intake stroke, as shown in FIGS. 5A and 6A, the working fluid 105 in the compression chamber 135 is expanded by the piston 123 operating in the direction of the arrow x that increases the volume of the compression chamber 135. As a result, the pressure in the compression chamber 135 decreases. When the pressure in the compression chamber 135 falls below the pressure in the suction muffler 157, the suction valve 141 opens due to the difference between the pressure in the compression chamber 135 and the pressure in the suction muffler 157. Accordingly, the low-temperature working fluid 105 returned from the refrigeration cycle is once released from the suction pipe 107 into the sealed container 101, and then flows into the compression chamber 135 through the suction muffler 157.

  Thereafter, in the compression stroke, as shown in FIGS. 5B and 6B, when the operation of the piston 123 turns in the direction of the arrow y in which the volume of the compression chamber 135 decreases from the bottom dead center, the compression chamber 135 The internal pressure rises, and the suction valve 141 is closed by the difference between the pressure in the compression chamber 135 and the pressure in the suction muffler 157. Along with this, the compression chamber 135 is closed, and the piston 123 operates in a direction in which the volume of the compression chamber 135 further decreases, so that the working fluid 105 is allowed to flow as shown in FIGS. 5 (c) and 6 (c). Compressed and pressurized to a predetermined pressure.

In the discharge stroke, when the pressure of the working fluid 105 in the compression chamber 135 rises and becomes higher than the pressure in the head space 155 formed by the valve plate 143 and the cylinder head 145, FIGS. As shown in (d), the discharge valve 153 starts to open due to the pressure difference. As a result, the working fluid 105 inside the compression chamber 135 passes through the discharge hole 151 and flows out to the head space 155.

  Then, the working fluid 105 flows from the head space 155 through the discharge muffler (not shown) to the high pressure side (not shown) of the refrigeration cycle through the discharge pipe 109.

  When the pressure in the compression chamber 135 falls below the pressure in the head space 155, the discharge valve 153 is closed, and the compression chamber 135 is closed accordingly, and the piston 123 moves in the direction of the bottom dead center and enters the suction stroke again. Transition.

  Here, at the top dead center position of the piston 123, a clearance is formed between the piston 123 and the valve plate 143 so as to avoid interference therebetween, and a small volume remains in the compression chamber 135. .

  In other words, the working fluid 105 remains inside the compression chamber 135 due to this minute volume. Since the remaining working fluid 105 is not discharged, after the remaining working fluid 105 expands in the suction stroke, the new working fluid 105 flowing in from the suction muffler 157 through the suction hole 149 is mixed and compressed. It becomes. An operation of opening the suction valve 141 when the working fluid 105 flows from the suction muffler 157 through the suction hole 149 will be described.

  First, in the conventional configuration, the clearance between the piston 123 and the valve plate 143 for avoiding the interference between the piston 123 and the valve plate 143 is reduced, or the volume of the protrusion 163 is increased, so that the compression chamber 135 becomes minute. When an attempt is made to reduce the volume and improve the efficiency of the electric compressor, the remaining working fluid 105 expands in the suction stroke until the working fluid 105 flows from the suction muffler 157 through the suction hole 149. The time becomes extremely short, and in the region A of FIG. 4, the suction valve tip 141a of the suction valve 141 and the tip surface 159 of the piston 123 come into contact as shown in FIG. There was a problem in terms of reliability such that 141 was missing.

  However, in the compressor according to the first embodiment, the groove 161 is provided on the front end surface 159 of the piston 123, and the groove 161 is disposed on the front end surface 159 from the position facing the suction valve front end 141a of the suction valve 141. The surface 159 is configured to extend toward a position facing the ejection hole 151. Thus, even when the suction valve tip 141a of the suction valve 141 and the tip surface 159 of the piston 123 approach each other, the suction valve tip 141a of the suction valve 141 and the piston 123 are separated by the groove 161 as shown in FIG. The contact of the front end surface 159 can be avoided, and the working fluid 105 compressed by the groove 161 can be discharged from the discharge hole 151 as much as possible, which is more reliable and more efficient than the hermetic compression. Can be a machine.

(Embodiment 2)
FIG. 7 is a longitudinal sectional view of the hermetic compressor according to the second embodiment of the present invention, FIG. 8 is an exploded perspective view of the compression element of the hermetic compressor according to the second embodiment, and FIG. FIG. 10 is a perspective view of a piston of the hermetic compressor in the second embodiment, and FIG. 10 is an enlarged view of a main part of the compression element of the hermetic compressor in the second embodiment. 11A to 11D are schematic diagrams for explaining the operation of the hermetic compressor in the second embodiment, and FIGS. 12A to 12D are hermetic compressors in the second embodiment. It is a schematic diagram for description of comparison for demonstrating the operation effect.

  In the second embodiment, the center axis of the groove having a predetermined width on the piston front end surface passes through the center point of the piston, and the other configurations are the same as those of the first embodiment, but the same part. Will be described with the same numbers in the 200s.

  As shown in FIGS. 7 to 9, the sealed container 201 stores oil 203 at the bottom, and further contains a refrigerant as a working fluid 205.

  The sealed container 201 is formed by drawing a steel plate and includes a suction pipe 207 and a discharge pipe 209. The suction pipe 207 is provided so as to penetrate the sealed container 201, and its upstream end is connected to the low pressure side (not shown) of the refrigeration cycle, and its downstream end communicates with the sealed container 201. The discharge pipe 209 is provided so as to penetrate the sealed container 201, and its upstream end communicates with a discharge muffler (not shown), and its downstream end is connected to the high-pressure side (not shown) of the refrigeration cycle. ing.

  In the sealed container 201, a compressor body 215 including a compression element 211 and an electric element 213 that drives the compression element 211 is housed. The compressor body 215 is elastically supported with respect to the sealed container 201 by a suspension spring 217.

  The compression element 211 includes a crankshaft 219, a cylinder block 221, a piston 223, a connecting means 225, and the like. The crankshaft 219 includes a main shaft 227 and an eccentric shaft 229.

  The electric element 213 includes a stator 231 fixed by bolts (not shown) below the cylinder block 221 and a rotor 233 that is disposed inside the stator 231 and is shrink-fitted and fixed to the main shaft 227. .

  The cylinder block 221 is integrally formed with a cylinder 237 that forms the compression chamber 235 and a bearing portion 239 that rotatably supports the main shaft 227.

  Further, as shown in FIG. 8, the suction valve 241, the valve plate 243, and the cylinder head 245 are arranged in this order on the end surface of the cylinder 237, and the end surface of the cylinder 237 is sealed by the head bolt 247. To be fixed. The valve plate 243 is provided with a suction hole 249 and a discharge hole 251 that communicate between the inside and outside of the compression chamber 235. The suction valve 241 is configured to open and close the suction hole 249. The cylinder head 245 is configured to cover the valve plate 243.

  A discharge valve 253 that opens and closes the discharge hole 251 is fixed to a surface of the valve plate 243 that faces the cylinder head 245. A head space 255 is formed by the valve plate 243 and the cylinder head 245. In addition, as shown in FIG. 7, a suction muffler 257 is gripped and fixed between the valve plate 243 and the cylinder head 245.

  Further, a protrusion 263 is provided on the front end surface 259 of the piston 223 that faces the valve plate 243 in the piston 223, and the protrusion 263 has a discharge hole 251 in the valve plate 243 when the piston 223 is located at the top dead center. It is formed so that it can be inserted into. Further, a belt-like (linear) groove 261 is provided on the distal end surface 259.

As shown in FIG. 9, the groove 261 is provided so as to extend from a position where the suction valve 241 faces the suction valve tip 241 a on the tip surface 259 toward a position facing the discharge hole 251 on the tip surface 259. Furthermore, in the second embodiment, the center axis of the groove 261 is wide so as to pass through the center point of the piston 223.

  The operation of the hermetic compressor configured as described above will be described below.

  The hermetic compressor causes a current to flow through the stator 231 to generate a magnetic field, and rotates the rotor 233 fixed to the main shaft 227, whereby the crankshaft 219 rotates. Along with this, the piston 223 reciprocates in the cylinder 237 via the connecting means 225 rotatably attached to the eccentric shaft 229.

  As the piston 223 reciprocates, the working fluid 205 is sucked into the compression chamber 235 via the suction muffler 257 and compressed, and then discharged from the discharge hole 251 through the head space 255 and the discharge pipe 209. It flows into a refrigeration cycle (not shown).

  Next, suction, compression, and discharge strokes of the working fluid 205 by the compressor body 215 will be described with reference to FIGS. 11 and 12.

  11A to 11D are schematic diagrams for explaining the operation of the hermetic compressor in the second embodiment, and FIGS. 12A to 12D are hermetic compressors in the second embodiment. 4A and 4B are schematic diagrams for explaining the operation, in which (a) is in the middle of the suction stroke, (b) is the end of the suction stroke (near the bottom dead center), and (c) is in the middle of the compression stroke. (D) shows the discharge stroke (near top dead center), respectively.

  In the suction stroke, as shown in FIGS. 11A and 12A, the piston 223 operates in the direction of the arrow x increasing the volume of the compression chamber 235, so that the working fluid 205 in the compression chamber 235 expands. As a result, the pressure in the compression chamber 235 decreases. When the pressure in the compression chamber 235 falls below the pressure in the suction muffler 257, the suction valve 241 opens due to the difference between the pressure in the compression chamber 235 and the pressure in the suction muffler 257. Accordingly, the low-temperature working fluid 205 returned from the refrigeration cycle is once released from the suction pipe 207 into the sealed container 201, and then flows into the compression chamber 235 through the suction muffler 257.

  Thereafter, in the compression stroke, as shown in FIGS. 11B and 12B, when the operation of the piston 223 turns from the bottom dead center in the direction of the arrow y in which the volume of the compression chamber 235 decreases, And the suction valve 241 is closed by the difference between the pressure in the compression chamber 235 and the pressure in the suction muffler 257. Accordingly, the compression chamber 235 is closed, and the piston 223 further moves in the direction in which the volume of the compression chamber 235 decreases, so that the working fluid 205 is allowed to flow as shown in FIGS. 11 (c) and 12 (c). Compressed and pressurized to a predetermined pressure.

  In the discharge stroke, when the pressure of the working fluid 205 in the compression chamber 235 increases and becomes higher than the pressure in the head space 255 formed by the valve plate 243 and the cylinder head 245, FIGS. As shown in (d), the discharge valve 253 starts to open due to the pressure difference. As a result, the working fluid 205 inside the compression chamber 235 passes through the discharge hole 251 and flows out to the head space 255.

  Then, the working fluid 205 flows from the head space 255 to the high pressure side (not shown) of the refrigeration cycle via the discharge muffler (not shown).

  When the pressure in the compression chamber 235 falls below the pressure in the head space 255, the discharge valve 253 is closed, and accordingly, the compression chamber 235 is closed, and the piston 223 moves in the direction of the bottom dead center and enters the suction stroke again. Transition.

  Here, at the top dead center position of the piston 223, a clearance is formed between the piston 223 and the valve plate 243 so as to avoid the interference therebetween, and a minute volume remains in the compression chamber 235. .

  That is, the working fluid 205 remains inside the compression chamber 235 due to this minute volume. Since the remaining working fluid 205 is not discharged, after the remaining working fluid 205 expands, the new working fluid 205 flowing from the suction muffler 257 through the suction hole 249 is mixed and compressed in the suction stroke. It becomes. An operation of opening the suction valve 241 when the working fluid 205 flows from the suction muffler 257 through the suction hole 249 will be described.

  First, in the conventional configuration, the clearance between the piston 223 and the valve plate 243 for avoiding the interference between the piston 223 and the valve plate 243 is reduced, or the volume of the protrusion 263 is increased, so that the compression chamber 235 can be made minute. When an attempt is made to reduce the volume and improve the efficiency of the electric compressor, the remaining working fluid 205 expands in the suction stroke until the working fluid 205 newly flows from the suction muffler 257 through the suction hole 249. The time becomes extremely short, and in the region B in FIG. 10, the suction valve tip 241a of the suction valve 241 and the tip surface 259 of the piston 223 are in contact with each other as shown in FIG. There was a problem in terms of reliability such that the valve 241 was missing.

  However, in the compressor according to the second embodiment, the groove 261 is provided on the front end surface 259 of the piston 223, and the groove 261 is disposed on the front end surface 259 from the position facing the suction valve front end 241a of the suction valve 241. The surface 259 extends toward the position facing the discharge hole 251, and the center axis of the groove 261 is wide so that it passes through the center point of the piston 223. As a result, even when the suction valve tip 241a of the suction valve 241 and the tip surface 259 of the piston 223 approach each other, the suction valve tip 241a of the suction valve 241 and the piston 223 are separated by the groove 261 as shown in FIG. The contact of the front end surface 259 can be avoided, and the working fluid 205 compressed by the wider groove 261 can be discharged from the discharge hole 251 as efficiently as possible, which is more reliable and more efficient than before. It is possible to provide a high-pressure hermetic compressor.

(Embodiment 3)
FIG. 13 is a longitudinal sectional view of a hermetic compressor according to Embodiment 3 of the present invention, FIG. 14 is an exploded perspective view of a compression element of the hermetic compressor according to Embodiment 2, and FIG. FIG. 16 is a perspective view of a piston of the hermetic compressor in the third embodiment, and FIG. 16 is an enlarged view of a main part of the compression element of the hermetic compressor in the third embodiment. 17A to 17D are schematic views for explaining the operation of the hermetic compressor in the third embodiment, and FIGS. 18A to 18D are hermetic compressors in the third embodiment. It is a schematic diagram for description of comparison for demonstrating the operation effect.

  In the third embodiment, the width of the piston front end surface is a trapezoid in which the discharge hole side is narrower and the suction valve front end side is wider, and the central axis of the trapezoid passes through the center point of the piston. The configuration is the same as that of the first embodiment, but the same parts will be described with the same numbers in the 300s.

   As shown in FIGS. 13 to 15, the sealed container 301 stores oil 303 at the bottom, and further contains a refrigerant as a working fluid 305.

The sealed container 301 is formed by iron plate drawing and includes a suction pipe 307 and a discharge pipe 309. The suction pipe 307 is provided so as to penetrate the sealed container 301, and an upstream end thereof is connected to a low-pressure side (not shown) of the refrigeration cycle, and a downstream end thereof communicates with the sealed container 301. The discharge pipe 309 is provided so as to pass through the sealed container 301, and its upstream end communicates with a discharge muffler (not shown), and its downstream end is connected to the high-pressure side (not shown) of the refrigeration cycle. ing.

  In the sealed container 301, a compressor main body 315 including a compression element 311 and an electric element 313 that drives the compression element 311 is housed. The compressor body 315 is elastically supported with respect to the sealed container 301 by suspension springs 317.

  The compression element 311 includes a crankshaft 319, a cylinder block 321, a piston 323, a connecting means 325, and the like. The crankshaft 319 includes a main shaft 327 and an eccentric shaft 329.

  The electric element 313 includes a stator 331 fixed by a bolt (not shown) below the cylinder block 321 and a rotor 333 that is disposed inside the stator 331 and is shrink-fitted to the main shaft 327 and fixed. .

  The cylinder block 321 is integrally formed with a cylinder 337 that forms the compression chamber 335 and a bearing portion 339 that rotatably supports the main shaft 327.

  Further, as shown in FIG. 14, a suction valve 341, a valve plate 343, and a cylinder head 345 are arranged in this order on the end surface of the cylinder 337, and the end surface of the cylinder 337 is sealed with a head bolt 347. To be fixed. The valve plate 343 is provided with a suction hole 349 and a discharge hole 351 that communicate between the inside and outside of the compression chamber 335. The suction valve 341 is configured to open and close the suction hole 349. The cylinder head 345 is configured to cover the valve plate 343.

  A discharge valve 353 that opens and closes the discharge hole 351 is fixed to a surface of the valve plate 343 facing the cylinder head 345. A head space 355 is formed by the valve plate 343 and the cylinder head 345. Further, as shown in FIG. 13, a suction muffler 357 is gripped and fixed between the valve plate 343 and the cylinder head 345.

  Further, a protrusion 363 is provided on the tip surface 359 of the piston 323 facing the valve plate 343 in the piston 323, and the protrusion 363 has a discharge hole 351 in the valve plate 343 when the piston 323 is located at the top dead center. It is formed so that it can be inserted into.

  Further, in the third embodiment, a trapezoidal groove 361 is provided on the front end surface 359 of the piston 323. As shown in FIG. 15, the groove 361 is provided so as to extend from the position facing the tip 341 a of the suction valve 341 on the tip surface 359 toward the position facing the discharge hole 351 on the tip surface 359, and The groove 361 has a trapezoidal shape in which the position of the suction valve 341 facing the suction valve tip 341a is wide, and the central axis of the trapezoid is provided so as to pass through the center point of the piston.

  The operation of the hermetic compressor configured as described above will be described below.

In the hermetic compressor, a current is passed through the stator 331 to generate a magnetic field, and the rotor 333 fixed to the main shaft 327 is rotated, whereby the crankshaft 319 is rotated. Along with this, the piston 323 reciprocates in the cylinder 337 via the connecting means 325 rotatably attached to the eccentric shaft 329.

  As the piston 323 reciprocates, the working fluid 305 is sucked into the compression chamber 335 via the suction muffler 357, compressed, and then discharged from the discharge hole 351, through the head space 355 and the discharge pipe 109. It flows into a refrigeration cycle (not shown).

  Next, suction, compression, and discharge strokes of the working fluid 305 by the compressor main body 315 will be described with reference to FIGS. 17 and 18.

  17A to 17D are schematic diagrams for explaining the operation of the hermetic compressor in the third embodiment, and FIGS. 18A to 18D are hermetic compressors in the second embodiment. 4A and 4B are schematic diagrams for explaining the comparison, in which (a) is in the middle of the suction stroke, (b) is the end of the suction stroke (near the bottom dead center), and (c) is the compression stroke. In the middle, (d) shows the discharge stroke (near top dead center).

  In the suction stroke, as shown in FIGS. 17A and 18A, the piston 323 operates in the direction of the arrow x that increases the volume of the compression chamber 335, so that the working fluid 305 in the compression chamber 335 expands. As a result, the pressure in the compression chamber 335 decreases. When the pressure in the compression chamber 335 falls below the pressure in the suction muffler 357, the suction valve 341 opens due to the difference between the pressure in the compression chamber 335 and the pressure in the suction muffler 357. Accordingly, the low-temperature working fluid 305 that has returned from the refrigeration cycle is once released from the suction pipe 307 into the sealed container 301, and then flows into the compression chamber 335 through the suction muffler 357.

  Thereafter, in the compression stroke, as shown in FIGS. 17B and 18B, when the operation of the piston 323 turns in the direction of the arrow y in which the volume of the compression chamber 335 decreases from the bottom dead center, And the suction valve 341 is closed by the difference between the pressure in the compression chamber 335 and the pressure in the suction muffler 357. Accordingly, the compression chamber 335 is closed, and the piston 323 further moves in the direction in which the volume of the compression chamber 335 decreases, so that the working fluid 305 is made to flow as shown in FIGS. 17 (c) and 18 (c). Compressed and pressurized to a predetermined pressure.

  In the discharge stroke, when the pressure of the working fluid 305 in the compression chamber 335 increases and becomes higher than the pressure in the head space 355 formed by the valve plate 343 and the cylinder head 345, FIG. 17 (d) and FIG. As shown in (d), the discharge valve 353 starts to open due to the pressure difference. As a result, the working fluid 305 inside the compression chamber 335 passes through the discharge hole 351 and flows out to the head space 355.

  Then, the working fluid 305 flows from the head space 355 through the discharge muffler (not shown) to the high pressure side (not shown) of the refrigeration cycle through the discharge pipe 309.

  When the pressure in the compression chamber 335 falls below the pressure in the head space 355, the discharge valve 353 is closed, and the compression chamber 335 is closed accordingly, and the piston 323 moves in the direction of the bottom dead center and enters the suction stroke again. Transition.

  Here, at the top dead center position of the piston 323, a clearance is formed between the piston 323 and the valve plate 343 to avoid interference between the piston 323 and a small volume remains in the compression chamber 335. .

In other words, the working fluid 305 remains in the compression chamber 335 due to this minute volume. Since the remaining working fluid 305 is not discharged, after the remaining working fluid 305 expands in the suction stroke, the working fluid 305 newly flowing from the suction muffler 357 through the suction hole 349 is mixed and compressed. It becomes. The operation of opening the suction valve 341 when the working fluid 305 flows from the suction muffler 357 through the suction hole 349 will be described.

  First, in the conventional configuration, the clearance between the piston 323 and the valve plate 343 for avoiding interference between the two is reduced, or the volume of the protrusion 363 is increased, so that the compression chamber 335 is made minute. When an attempt is made to reduce the volume and improve the efficiency of the electric compressor, the remaining working fluid 305 expands in the suction stroke until the working fluid 305 newly flows from the suction muffler 357 through the suction hole 349. In the region C in FIG. 16, the suction valve tip 341a of the suction valve 341 and the tip surface 359 of the piston 323 are in contact with each other as shown in FIG. There was a problem in reliability such as lack of.

  However, in the compressor according to the third embodiment, the groove 361 is provided on the tip surface 359 of the piston 323, and the groove 361 is disposed on the tip surface 359 from the position facing the suction valve tip 341a of the suction valve 341. The groove 361 has a trapezoidal shape in which the position of the suction valve 341 facing the suction valve tip 341a is wider, and the central axis of the trapezoid is The configuration passes through the center point. Thus, even when the suction valve tip 231a of the suction valve 341 and the tip surface 359 of the piston 323 approach each other, as shown in FIG. 17A, the suction valve tip 341a of the suction valve 341 and the piston 323 are separated by the groove 361. The contact of the front end surface 359 can be avoided, and the working fluid 305 compressed by the trapezoidal groove 361 can be smoothly guided toward the discharge hole 351 and discharged from the discharge hole 251 more efficiently. It is possible to provide a hermetic compressor with higher reliability and higher efficiency than before.

  As described above, since the hermetic compressor according to the present invention has high reliability and high efficiency, it is widely used as a hermetic compressor such as a refrigerator, a freezer showcase, a dehumidifier air conditioner, and a vending machine. Can be applied.

101, 201, 301 Sealed container 103, 203, 303 Oil 105, 205, 305 Working fluid 107, 207, 307 Suction pipe 109, 209, 309 Discharge pipe 111, 211, 311 Compression element 113, 213, 313 Electric element 115, 215, 315 Compressor body 117, 217, 317 Suspension spring 119, 219, 319 Crankshaft 121, 221, 321 Cylinder block 123, 223, 323 Piston 125, 225, 325 Connecting means 127, 227, 327 Main shaft 129, 229, 329 Eccentric shaft 131,231,331 Stator 133,233,333 Rotor 135,235,335 Compression chamber 137,237,337 Cylinder 139,239,339 Bearing part 141,241,341 Inlet valve 141a, 241a, 341a Suction valve tip 143, 243, 343 Valve plate 145, 245, 345 Cylinder head 147, 247, 347 Head bolt 149, 249, 349 Suction hole 151, 251, 351 Suction hole 153, 253, 353 Discharge valve 155, 255, 355 Head space 157, 257, 357 Suction muffler 159, 259, 359 End face 161, 261, 361 Groove 163, 263, 363 Protrusion

Claims (1)

An electric element;
A compression element driven by the electric element;
A sealed container in which the electric element and the compression element are accommodated;
The compression element is
A cylinder block forming a compression chamber,
A piston that reciprocates in the compression chamber;
A valve plate that is disposed so as to close the open end of the compression chamber, and in which a discharge hole that communicates with the outside of the compression chamber is formed;
A suction valve for opening and closing the suction hole of the valve plate,
A protrusion is provided on the tip surface of the piston facing the valve plate,
The protrusion is formed so as to be inserted into the discharge hole of the valve plate when the piston is located at the top dead center.
A front end surface of the piston facing the valve plate passes through a position facing the discharge hole of the valve plate from an outer peripheral edge of the front end surface, and further extends toward a position facing the front end of the suction valve. A width groove is provided ,
The groove has a trapezoidal shape in which the discharge hole side is narrow and the suction valve tip side is wide, and the trapezoidal central axis passes through the center point of the piston .

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