JP2007255248A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor having smaller variations of performance and efficiency between respective compressors. <P>SOLUTION: The compressor has an intake valve 137 formed by an intake hole 131 drilled on a valve plate 119, an intake valve seat 132 formed on the outer periphery at a cylinder bore 114 side of the intake hole 131, and a sheetlike intake lead 136 for opening and closing the intake valve seat 132. The valve seat surface of the intake valve seat 132 is formed to come below the surface at a cylinder bore 114 side of the valve plate 119. Thus, a stable spring force in an opening direction is generated on the intake lead 136 in a closure state of the intake valve 137 so that height of the valve seat surface of the intake valve seat 132 is precisely finished by processing with the performance and efficiency of the compressor improved, and variations lessened between respective compressors. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compressor used in a refrigerator.

  Conventionally, this type of compressor has an improved intake valve device for higher efficiency (for example, see Patent Document 1).

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

  13 is a cross-sectional view showing a conventional compressor described in Patent Document 1, FIG. 14 is a cross-sectional view of a main part of the conventional compressor, FIG. 15 is a plan view of a suction lead of the conventional compressor, and FIG. It is a perspective view of the suction lead of the compressor of.

  13 to 16, the container 1 houses a stator 2, an electric element 4 including a rotor 3, and a compression mechanism 5 driven thereby.

  Next, details of the compression mechanism 5 will be described below.

  The crankshaft 10 includes a main shaft portion 11 press-fitted and fixed to the rotor 3 and an eccentric portion 12 formed eccentric to the main shaft portion 11. The block 13 has a substantially cylindrical cylinder bore 14 and a bearing portion 15 that supports the main shaft portion 11.

  The piston 16 loosely fitted in the cylinder bore 14 is connected to the eccentric portion 12 via a piston pin 17 by a connecting rod 18 as a connecting means. The end face of the cylinder bore 14 is sealed with a valve plate 19 and constitutes a compression chamber 20 together with the piston 16.

  The head 21 forms a high-pressure chamber and is fixed to the valve plate 19 on the side opposite to the cylinder bore 14. The suction tube 22 is fixed to the container 1 and connected to the primary side (not shown) of the apparatus, and guides a working fluid (not shown) into the container 1. The suction muffler 23 is sandwiched between the valve plate 19 and the head 21.

  The valve plate 19 includes a suction hole 31 and a suction valve seat 32, and connects the circular head 33, the base 34, the circular head 33, and the base 34 formed by providing a slit 24 in a thin spring steel material. A suction valve 37 is configured together with a suction lead 36 including an arm portion 35. The arm portion 35 is bent at a refracting portion 38 that forms an acute angle with the axis of the arm portion 35.

  The valve plate 19 has a discharge hole (not shown) and a discharge valve seat (not shown) on the side opposite to the cylinder bore 14, and constitutes a discharge valve (not shown) together with a discharge lead (not shown).

  The suction lead 36 is bolted to the block 13 together with the valve plate 19, the head gasket (not shown), and the head 21 via a plate gasket 50 having a circular cutout corresponding to the cylinder bore 14.

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

  When the electric element 4 is energized from an external power source, the rotor 3 rotates. The rotor 3 rotates the crankshaft 10, and the eccentric movement of the eccentric portion 12 drives the piston 16 from the connecting rod 18 of the connecting means through the piston pin 17, so that the piston 16 reciprocates in the cylinder bore 14 and is compressed. The mechanism 5 performs a predetermined compression operation.

  The working fluid introduced into the container 1 through the suction tube 22 is sucked from the suction muffler 23 through the suction valve 37 by this compression operation, continuously compressed in the compression chamber 20, and discharged from a discharge valve (not shown). Is done.

  When the working fluid is sucked into the compression chamber 20 through the suction valve 37, the bending portion of the refracting portion 38 of the suction lead 36 is bent so that the arm portion 35 and the circular head 33 of the suction lead 36 are closed when the suction valve 37 is closed. The spring force for opening the intake valve 37 is generated by elastic deformation.

As a result, the delay in opening the suction lead 36 due to sticking of the suction valve seat 32 and the circular head 33 due to the oil viscosity is avoided, and the amount of working fluid (not shown) sucked into the compression chamber 20 is increased, thereby improving efficiency. improves.
JP-A-60-227075

  However, in the above-described conventional configuration, the bending process of the refracting portion 38 plastically deforms the thin plate, so that the amount of refraction is not stabilized due to wear of the spring back of the thin plate or the bending jig, etc., and the capacity and efficiency of the compressor vary between individuals. Had problems.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a compressor with small variations in capacity and efficiency between individuals.

  In order to solve the above-described conventional problems, the compressor according to the present invention is such that the valve seat surface of the intake valve seat is formed lower than the cylinder bore side surface of the valve plate, and the height of the valve seat surface of the intake valve seat is high. Since the thickness can be accurately obtained by processing, a stable spring force in the opening direction is generated in the suction lead when the suction valve is closed.

  In the compressor of the present invention, the height of the valve seat surface of the suction valve seat is finished with high precision by machining, and a stable spring force in the opening direction is generated in the suction lead when the suction valve is closed. Responsiveness is improved, performance and efficiency are improved, and variation among individuals can be reduced.

  The invention according to claim 1 includes a block in which a cylinder bore is formed, a piston that reciprocates within the cylinder bore, and a valve plate that is arranged to seal the cylinder bore opening end of the block, A suction valve formed by a suction hole formed in the valve plate, a suction valve seat formed on an outer periphery of the suction hole on the cylinder bore side, and a thin plate-like suction lead that opens and closes the suction valve seat; And the intake valve seat has a valve seat surface formed lower than the surface of the valve plate on the cylinder bore side, and the height of the valve seat surface of the intake valve seat is precisely finished by machining. In the closed state of the suction lead, a stable spring force is generated in the opening direction, improving the response of the suction lead, improving performance and efficiency, and variation among individuals It can be reduced.

  The invention according to claim 2 is the invention according to claim 1, wherein the valve plate is provided with a suction valve seat and an inclined portion directed from the peripheral portion to a portion corresponding to the base portion of the suction lead. The increase in re-expansion volume is suppressed as compared with the case where the portion corresponding to the base portion of the suction lead is continued, and the performance and efficiency are further improved in addition to the effect of the invention of claim 1.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the valve seat surface of the intake valve seat is inclined in accordance with the inclination when the intake lead is closed, and the intake valve is closed. 3. In addition to the effects of the invention according to claim 1, the suction lead collides with the valve seat surface of the suction valve seat at the same time substantially in the entire circumference and has good sealing performance when closed. Durability is improved and performance and efficiency are improved.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the peripheral portion and the end of the inclined portion are located within the extension range of the cylinder bore, and the assembled state The surface of the valve plate is outside the extension range of the cylinder bore to which the suction lead is pressed, so that the suction lead can be prevented from being deformed by pressing, and when the suction valve is closed, a constant spring in the opening direction is applied to the suction lead. Since force is generated, in addition to the effects of the invention according to any one of claims 1 to 3, the variation in performance and efficiency among individuals can be further reduced.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the suction lead is formed by providing a slit in a thin plate-shaped spring steel material. Since the suction lead can be bolted together with parts such as a valve plate, productivity is further improved in addition to the effects of the invention according to any one of claims 1 to 4.

  Embodiments of a compressor according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
1 is a cross-sectional view of a compressor according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view of main parts of the compressor according to the same embodiment, and FIG. 3 is a cross-sectional view of main parts of the compressor according to the same embodiment. FIG. 4 is an enlarged view, FIG. 4 is a plan view showing a valve plate of the compressor in the same embodiment, FIG. 5 is a plan view showing a suction lead of the compressor in the same embodiment, and FIG. 6 is in the same embodiment. It is a top view which shows the plate gasket of a compressor.

  1 to 6, a container 101 contains a stator 102, an electric element 104 including a rotor 103, and a compression mechanism 105 driven by the electric element 104.

  Next, details of the compression mechanism 105 will be described below.

  The crankshaft 110 includes a main shaft portion 111 press-fitted to the rotor 103 and an eccentric portion 112 formed eccentrically with respect to the main shaft portion 111. The block 113 has a substantially cylindrical cylinder bore 114 and a bearing portion 115 that supports the main shaft portion 111.

  The piston 116 loosely fitted in the cylinder bore 114 is connected to the eccentric portion 112 via a piston pin 117 by a connecting rod 118 as a connecting means. The end face of the cylinder bore 114 is sealed with a valve plate 119 and constitutes a compression chamber 120 together with the piston 116.

  The head 121 forms a high-pressure chamber and is fixed to the side of the valve plate 119 opposite to the cylinder bore 114. The suction tube 122 is fixed to the container 101 and connected to the primary side (not shown) of the apparatus, and guides a working fluid (not shown) into the container 101. The suction muffler 123 is sandwiched between the valve plate 119 and the head 121.

  The valve plate 119 includes a suction hole 131 and a suction valve seat 132. The suction lead 136 includes a reed valve including a circular head 133 formed by providing a slit 124 in a thin plate-shaped spring steel material, a base 134, and an arm 135 connecting the circular head 133 and the base 134. The suction lead 136 and the valve plate 119 constitute a suction valve 137.

  The valve seat surface 132a of the suction valve seat 132 is formed lower than the surface 119a on the cylinder bore 114 side of the valve plate 119 (A shown in FIG. 3), and is spaced from the position of the suction lead 136 in the unstressed state. Can do.

  An inclined portion 139 whose height increases from the peripheral portion 138 of the suction valve seat 132 toward the direction corresponding to the arm portion 135 and the base portion 134 of the suction lead 136 is provided. At this time, the end 140 on the base 134 side of the inclined portion 139 is within the imaginary line of the extension range 146 of the cylinder bore 114.

  The valve plate 119 has a discharge hole (not shown) and a discharge valve seat (not shown), and constitutes a discharge valve (not shown) together with a discharge lead (not shown).

  The suction lead 136 is bolted to the block 113 together with the valve plate 119, a head gasket (not shown), and the head 121 via a plate gasket 150 having a circular cutout corresponding to the cylinder bore 114.

  About the compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the electric element 104 is energized from an external power source, the rotor 103 rotates. The rotor 103 rotates the crankshaft 110, and the eccentric motion of the eccentric portion 112 drives the piston 116 from the connecting rod 118 of the connecting means through the piston pin 117, whereby the piston 116 reciprocates in the cylinder bore 114, and is compressed. The mechanism 105 performs a predetermined compression operation.

  The working fluid introduced into the container 101 through the suction tube 122 is sucked into the compression chamber 120 from the suction muffler 123 via the suction valve 137 by this compression operation, and is continuously compressed in the compression chamber 120 and discharged (see FIG. It is discharged from (not shown).

  When the working fluid is sucked into the compression chamber 120 via the suction valve 137, the valve seat surface 132a of the suction valve seat 132 is located at a position lower than the surface 119a on the cylinder bore 114 side of the valve plate 119. When the valve is closed, a spring force for opening the suction valve 137 is generated by elastic deformation in the arm portion 135 and the circular head 133 of the suction lead 136.

  As a result, sticking due to oil viscosity between the valve seat surface 132a of the suction valve seat 132 and the circular head 133, and sticking due to oil viscosity between the surface 119a of the valve plate 114 and the inclined portion 139 and the arm portion 135. Since the opening delay of the suction lead 136 due to attachment can be prevented and the response is improved, the amount of working fluid (not shown) sucked into the compression chamber 120 is increased, and the capacity and efficiency are improved.

  At this time, the step dimension between the surface 119a of the valve plate 119 on the cylinder bore 114 side and the valve seat surface 132a of the suction valve seat 132 is determined by the thickness and shape of the circular head 133 and arm portion 135 of the suction lead 136. There are optimum specifications depending on the constants, eigenvalues, the area of the valve seat surface 132a of the suction valve seat 132, and the sticking due to oil viscosity, but it is experimental that it is generally within the range of 0.1 mm to 0.7 mm. I understood. On the contrary, a large level difference exceeding 0.7 mm causes deterioration of the sealing performance when closed. The determined step size can be accurately reproduced by machining, and as a result, variation in ability and efficiency between individuals is improved. In order to suppress variation between individuals, it is preferable to manage the dimensions within a range of 0.2 mm with respect to the determined optimum step size.

  Further, in order to make the length of the arm portion 135 of the suction lead 136 effective, it is necessary to increase the range of the peripheral portion 138 and the inclined portion 139 that determine the movable range of the suction lead 136 toward the valve plate 119 side. By increasing the height of the inclined portion 139 from the peripheral portion 138 toward the direction corresponding to the arm portion 135 and the base portion 134 of the suction lead 136, an increase in the re-expansion volume is suppressed, and a decrease in the capacity and efficiency of the compressor is suppressed. be able to.

  Further, the positions of the peripheral portion 138 and the terminal end 140 of the inclined portion 139 are within the extension range 146 of the cylinder bore 114, so that the portion of the valve plate 119 that is pressed by the plate gasket 150 in the assembled state is disposed in the cylinder of the valve plate 119. Since the surface 119a on the bore 114 side is in close contact, the suction lead 136 is not deformed, and the spring force when the suction lead 136 is closed does not vary between individuals, so that variation in ability and efficiency between individuals is improved. .

  In addition, since the suction lead 136 does not block the valve seat surface 132a of the suction valve seat 132 in the non-stressed state, the valve seat surface of the suction valve seat 132 during the period when the rotation speed of the rotor 103 increases at the time of starting the compressor. Appropriate leakage occurs in the seal portion between 132a and the suction lead 136 to act as an unloader to improve the startability of the compressor.

  In addition, since the suction lead 136 is formed by providing a slit 124 in a thin plate-shaped spring steel material, the suction lead 136 is assembled via the plate gasket 150 through the plate gasket 150 during assembly, the head plate (not shown), the head. Since the bolts can be fastened to the block 113 together with 121, the productivity is improved.

(Embodiment 2)
7 is a cross-sectional view of the compressor according to the second embodiment of the present invention, FIG. 8 is a cross-sectional view of the main portion of the compressor according to the same embodiment, and FIG. 9 is a cross-sectional view of the main portion of the compressor according to the same embodiment. FIG. 10 is an enlarged view, FIG. 10 is a plan view showing a valve plate of the compressor in the same embodiment, FIG. 11 is a plan view showing a suction lead of the compressor in the same embodiment, and FIG. 12 is in the same embodiment. It is a top view which shows the plate gasket of a compressor.

  7 to 12, a container 201 contains a stator 202, an electric element 204 including a rotor 203, and a compression mechanism 205 driven thereby.

  Next, details of the compression mechanism 205 will be described below.

  The crankshaft 210 includes a main shaft portion 211 press-fitted and fixed to the rotor 203 and an eccentric portion 212 formed eccentric to the main shaft portion 211. The block 213 has a substantially cylindrical cylinder bore 214 and a bearing portion 215 that supports the main shaft portion 211.

  The piston 216 loosely fitted in the cylinder bore 214 is connected to the eccentric portion 212 via a piston pin 217 by a connecting rod 218 as a connecting means. The end face of the cylinder bore 214 is sealed with a valve plate 219 and constitutes a compression chamber 220 together with the piston 216.

  The head 221 forms a high pressure chamber and is fixed to the side of the valve plate 219 opposite to the cylinder bore 214. The suction tube 222 is fixed to the container 201 and connected to the primary side (not shown) of the apparatus, and guides a working fluid (not shown) into the container 201. The suction muffler 223 is sandwiched between the valve plate 219 and the head 221.

  The valve plate 219 includes a suction hole 231 and a suction valve seat 232. The suction lead 236 includes a reed valve including a circular head 233 formed by providing a slit 224 in a thin plate-shaped spring steel material, a base 234, and an arm 235 that connects the circular head 233 and the base 234. The suction lead 236 and the valve plate 219 constitute a suction valve 237.

  The valve seat surface 232a of the suction valve seat 232 is formed lower than the surface 219a on the cylinder bore 214 side of the valve plate 219 (B shown in FIG. 9), and is spaced from the position of the suction lead 236 in the unstressed state. Can do.

  An inclined portion 239 whose height increases from a peripheral portion 238 of the suction valve seat 232 toward a direction corresponding to the arm portion 235 and the base portion 234 of the suction lead 236 is provided. At this time, the end 240 of the inclined portion 239 on the base portion 234 side is within the imaginary line of the extension range 246 of the cylinder bore 214.

  Further, the valve seat surface 232a of the suction valve seat 232 has an inclination in accordance with the inclination when the suction lead 236 is closed, and the peripheral portion 238 and the inclined portion 239 are not higher than the position when the suction lead 236 is closed.

  The valve plate 219 has a discharge hole (not shown) and a discharge valve seat (not shown), and constitutes a discharge valve (not shown) together with a discharge lead (not shown).

  The suction lead 236 is bolted to the block 213 together with the valve plate 219, the head gasket (not shown), and the head 221 through a plate gasket 250 having a circular cutout corresponding to the cylinder bore 214.

  About the compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the electric element 204 is energized from an external power source, the rotor 203 rotates. The rotor 203 rotates the crankshaft 210, and the eccentric movement of the eccentric portion 212 drives the piston 216 from the connecting rod 218 of the connecting means via the piston pin 217, whereby the piston 216 reciprocates in the cylinder bore 214 and compresses. The mechanism 205 performs a predetermined compression operation.

  The working fluid introduced into the container 201 through the suction tube 222 is sucked from the suction muffler 223 through the suction valve 237 by this compression operation, continuously compressed in the compression chamber 220, and discharged from a discharge valve (not shown). Is done.

  When the working fluid is sucked into the compression chamber 220 through the suction valve 237, the valve seat surface 232a of the suction valve seat 232 is at a lower position than the surface 219a on the cylinder bore 214 side of the valve plate 219. At the time of closing, a spring force for opening the suction valve 237 is generated by elastic deformation in the arm portion 235 and the circular head portion 233 of the suction lead 236.

  As a result, sticking due to oil viscosity between the valve seat surface 232a of the suction valve seat 232 and the circular head 233 and sticking due to oil viscosity between the surface 219a of the cylinder bore 214 of the valve plate 219 and the inclined portion 239 and the arm portion 235. Since the opening delay of the suction lead 236 due to attachment can be prevented and the responsiveness is improved, the amount of working fluid (not shown) sucked into the compression chamber 220 is increased, and the performance and efficiency are improved.

  At this time, the step size of the valve plate surface 219a of the valve plate 219 on the cylinder bore 214 side and the valve seat surface 232a of the suction valve seat 232 is determined by the plate thickness and shape of the circular head 233 and the arm 235 of the suction lead 236. Although there are optimum specifications depending on the constants and eigenvalues, the area of the valve seat surface 232a of the suction valve seat 232, and the difference in sticking due to the oil viscosity, it is experimentally that it is generally within the range of 0.1 mm to 0.7 mm. I understood. On the contrary, a large level difference exceeding 0.7 mm causes deterioration of the sealing performance when closed. The determined step size can be accurately reproduced by machining, and as a result, the variation in performance and efficiency among individuals is improved. In order to suppress variation between individuals, it is preferable to manage the dimensions within a range of 0.2 mm with respect to the determined optimum step size.

  In order to make the length of the arm portion 235 of the suction lead 236 effective, it is necessary to increase the range of the peripheral portion 238 and the inclined portion 239 that determine the movable range of the suction lead 236 toward the valve plate 219. By increasing the height of the inclined portion 239 from the peripheral portion 238 toward the direction corresponding to the arm portion 235 and the base portion 234 of the suction lead 236, an increase in the re-expansion volume is suppressed, and a decrease in the capacity and efficiency of the compressor is suppressed. be able to.

  Further, by setting the positions of the peripheral portion 238 and the end 240 of the inclined portion 239 within the extension range 246 of the cylinder bore 214, the cylinder of the valve plate 219 is not provided in the portion where the suction lead 236 is pressed by the plate gasket 250 in the assembled state. Since the surface 219a on the side of the bore 214 is in close contact, the suction lead 236 is not deformed, and the spring force when the suction lead 236 is closed does not vary between individuals, so that variation in ability and efficiency between individuals is improved. .

  In addition, since the suction lead 236 does not block the valve seat surface 232a of the suction valve seat 232 in the non-stressed state, the valve seat surface of the suction valve seat 232 during the period when the rotational speed of the rotor 203 increases when the compressor is started. Appropriate leakage occurs in the seal portion between the 232a and the suction lead 236 to act as an unloader, thereby improving the startability of the compressor.

  Further, the suction lead 236 is formed by providing a slit in a thin plate-shaped spring steel material. During assembly, the suction lead 236 is connected to the valve plate 219, the head gasket (not shown), the head 221 via the plate gasket 250. In addition, since the bolts can be fastened to the block 213, productivity is improved.

  Further, when the suction lead 236 collides with the suction valve seat 232 when the suction lead 236 is closed, the valve seat surface 232a of the suction valve seat 232 is formed with a sloped surface that matches the slope of the suction lead 236 when closed. In addition, by making the inclined portion 239 lower than the closed position of the suction lead 236, the circular head 233 of the suction lead 236 collides almost entirely over the entire circumference of the valve seat surface 232a of the suction valve seat 232. As a result, it is possible to prevent the suction lead 236 from coming into contact with each other and to suppress an impact applied to the suction valve seat 232 and the suction lead 236, thereby improving durability. Further, since the suction lead 236 is seated almost simultaneously over the entire circumference substantially parallel to the valve seat surface 232a of the suction valve seat 232, the sealing performance is improved, and the performance and efficiency are improved.

  Note that the inclination when the suction lead 236 is closed can be obtained by actual measurement or CAE.

  As described above, the compressor according to the present invention finishes the height of the suction valve seat with high accuracy by machining, so that a stable spring force in the opening direction is generated in the suction lead in the closed state of the suction valve. Since it is efficient and can reduce variation among individuals, it can be applied to uses such as air conditioning and vending machines in addition to refrigerators.

Sectional drawing of the compressor in Embodiment 1 of this invention Sectional drawing of the principal part of the compressor of the embodiment Cross-sectional enlarged view of the main part of the compressor of the embodiment The top view which shows the valve plate of the compressor of the embodiment The top view which shows the suction | inhalation lead of the compressor of the embodiment The top view which shows the plate gasket of the compressor of the embodiment Sectional drawing of the compressor in Embodiment 2 of this invention Sectional drawing of the principal part of the compressor of the embodiment Cross-sectional enlarged view of the main part of the compressor of the embodiment The top view which shows the valve plate of the compressor of the embodiment The top view which shows the suction | inhalation lead of the compressor of the embodiment The top view which shows the plate gasket of the compressor of the embodiment Cross section of a conventional compressor Cross section of the main part of a conventional compressor Plan view showing suction lead of a conventional compressor A perspective view showing a suction lead of a conventional compressor

Explanation of symbols

113, 213 Block 114, 214 Cylinder bore 116, 216 Piston 119, 219 Valve plate 119a, 219a Surface 124, 224 Slit 131, 231 Suction hole 132, 232 Suction valve seat 132a, 232a Valve seat surface 134, 234 Base 136, 236 Suction lead 137, 237 Suction valve 138, 238 Peripheral part 139, 239 Inclined part 140, 240 Termination 146, 246 Extension range

Claims (5)

  A suction hole having a block formed with a cylinder bore, a piston that reciprocates within the cylinder bore, and a valve plate disposed so as to seal the cylinder bore opening end of the block. And a suction valve seat formed on the outer periphery of the suction hole on the cylinder bore side, and a thin-plate suction lead that opens and closes the suction valve seat, and a valve of the suction valve seat A compressor in which a seat surface is formed lower than a surface of the valve plate on the cylinder bore side.   The compressor according to claim 1, wherein the valve plate is provided with a suction valve seat and an inclined portion directed from a peripheral portion to a portion corresponding to a base portion of the suction lead.   The compressor according to claim 1 or 2, wherein the valve seat surface of the suction valve seat is inclined in accordance with the inclination when the intake lead is closed.   The compressor according to any one of claims 1 to 3, wherein the peripheral portion and the end of the inclined portion are located within an extension range of the cylinder bore.   The compressor according to any one of claims 1 to 4, wherein the suction lead is formed by providing a slit in a thin plate-shaped spring steel material.

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