JP2010144921A - Relief valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relief valve capable of preventing a first body from being welded to a valve element by ultrasonic welding while having a casing formed by welding first and second bodies by ultrasonic welding. <P>SOLUTION: A first body 32 and a second body 33 are formed of a thermoplastic resin (polyetherimide resin) made of the same material. A valve element 40 is formed of a thermoplastic resin (polybutylene terephthalate resin) made of a material different from that forming the first body 32 and second body 33. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a casing in which a first body made of a resin material in which a gas inlet is formed and a second body made of a resin material in which a gas outlet is formed are welded by ultrasonic welding. Related to relief valve.

  For example, during operation of a refrigerant compressor used in a refrigerant circuit of a vehicle air conditioner, the discharge chamber provided in the refrigerant compressor is in a high pressure state, but the pressure in the discharge chamber exceeds a predetermined value and becomes abnormally high. In this case, it is necessary to reduce the pressure in the discharge chamber and prevent the refrigerant compressor from being destroyed. For this reason, the refrigerant compressor is equipped with a relief valve for releasing the refrigerant gas in the discharge chamber to the outside (see, for example, Patent Document 1).

The relief valve of Patent Document 1 includes a cup-shaped body (first body), a pressure inlet (inlet) is formed at the center bottom of the body, and a valve seat is formed at the inner periphery of the pressure inlet. Is formed. A valve body is housed in the body, and a compression coil spring is housed inside the valve body guide portion of the valve body. A plate (second body) having a passage (discharge port) at the center is fixed to the upper opening of the body.
JP 2001-12628 A

  In the relief valve disclosed in Patent Document 1, a synthetic resin valve body made of the same material as that of the body is housed in the body and a compression coil spring is housed, and then the upper part of the body is made of the same material as the body. It is manufactured by welding a plate made of synthetic resin by ultrasonic welding. However, when the body and the plate are welded by ultrasonic welding, the body and the plate are vibrated by the ultrasonic vibration, and the valve body in the body vibrates accordingly, and the body and the valve body come into contact with each other. End up. When the body and the valve body are made of the same synthetic resin as in Patent Document 1, frictional heat due to ultrasonic vibration is generated on the contact surface between the body and the valve body, and the contact surface between the body and the valve body. Melted and welded to each other, and there was a problem that the valve body could not move in the body.

  An object of the present invention is to prevent the first body and the valve body from being welded by ultrasonic welding while having a casing formed by welding the first body and the second body by ultrasonic welding. It is to provide a relief valve that can be used.

  In order to achieve the above-mentioned object, the invention according to claim 1 includes a first body made of a resin material in which a gas inflow port is formed, and a second body made of a resin material in which a gas discharge port is formed. Is a relief valve that includes a casing welded by ultrasonic welding, and that houses a valve body that opens and closes the inflow port in the casing, wherein the first body and the second body are made of the same material. The gist of the invention is that the valve body is made of a material different from the resin material forming the first body and the second body.

  Ultrasonic welding has the property of melting and joining materials of the same material, and when intensive expansion and contraction occurs on the contact surfaces of materials of the same material due to ultrasonic vibration transmitted to each material. Friction heat is generated on the contact surface. Then, the contact surfaces are melted, the contact surfaces are joined, and materials of the same material are welded together by ultrasonic welding. Therefore, when the valve body is formed of a material different from the resin material forming the first body and the second body, a concentrated expansion and contraction motion is caused on the contact surface between the first body and the valve body during ultrasonic welding. Even if frictional heat is generated and the first body and the valve body are not melted, the first body and the valve body are not welded to each other. Therefore, even if the casing is formed by ultrasonic welding, it is possible to prevent the first body and the valve body from being welded by ultrasonic welding.

  According to the present invention, it is possible to prevent the first body and the valve body from being welded by ultrasonic welding while including the casing formed by welding the first body and the second body by ultrasonic welding. it can.

Hereinafter, an embodiment in which the present invention is embodied in a relief valve used in a refrigerant circuit of a vehicle air conditioner will be described with reference to FIG.
First, the refrigerant circuit of the vehicle air conditioner will be described.

  As shown in FIG. 1A, the refrigerant circuit 10 includes a refrigerant compressor 11 that compresses a refrigerant gas as a gas, a condenser C that cools a high-pressure refrigerant gas from the refrigerant compressor 11, and a condenser C An expansion valve V that throttles the refrigerant, and an evaporator E that evaporates the refrigerant from the expansion valve V are provided.

  The housing of the refrigerant compressor 11 includes a cylinder block 12, a front housing 13 joined to the front side of the cylinder block 12, and a rear housing 14 joined to the rear side of the cylinder block 12. In the rear housing 14, a discharge chamber Da and a suction chamber Sa are formed. In FIG. 1A, the right side of the refrigerant compressor 11 is defined as the rear side, and the left side is defined as the front side.

  A suction passage 16 is formed in the rear housing 14. One end of the suction passage 16 communicates with the suction chamber Sa and the other end of the suction passage 16 is connected to the evaporator E in the refrigerant circuit 10. A discharge passage 17 is formed in the rear housing 14. One end of the discharge passage 17 communicates with the discharge chamber Da, and the other end of the condenser C in the refrigerant circuit 10 is connected to the other end. The refrigerant compressor 11 compresses the refrigerant gas sucked from the suction chamber Sa in a compression chamber (not shown), and discharges the compressed high-pressure refrigerant gas to the discharge chamber Da. The refrigerant gas discharged into the discharge chamber Da flows into the condenser C from the discharge passage 17. Further, the refrigerant that has passed through the expansion valve V and the evaporator E flows from the suction passage 16 into the suction chamber Sa.

  A mounting hole 15 is formed in the rear housing 14. One end of the mounting hole 15 communicates with the discharge chamber Da and the other end is open to the atmosphere outside the refrigerant compressor 11. As shown in FIG. 1B, the discharge hole Da side of the mounting hole 15 is a large-diameter portion 15a, and the atmosphere side from the large-diameter portion 15a is a small-diameter portion 15b having a smaller diameter than the large-diameter portion 15a. . Furthermore, the contact part 15e is extended toward the inner side of the small diameter part 15b in the edge part by the side of the atmosphere in the small diameter part 15b. A locking step 15c is formed on the peripheral surface of the mounting hole 15 between the large-diameter portion 15a and the small-diameter portion 15b over the entire circumference of the mounting hole 15, and from the large-diameter portion 15a to the discharge chamber Da. On the side, an engagement recess 15 d is provided over the entire circumference of the mounting hole 15. A relief valve 30 is mounted in the mounting hole 15. The relief valve 30 releases the refrigerant gas in the discharge chamber Da to the atmosphere for the purpose of reducing the pressure in the discharge chamber Da when the discharge chamber Da has an abnormally high pressure.

Next, the configuration of the relief valve 30 will be described.
The outline of the relief valve 30 is formed by a casing 31 having a substantially cylindrical shape. The casing 31 is formed by welding and integrating a first body 32 having a substantially cylindrical shape and a second body 33 having a substantially cylindrical shape by ultrasonic welding.

  The first body 32 and the second body 33 are each made of a thermoplastic resin (for example, a polyetherimide resin), which is a resin material of the same material, and is manufactured by injection molding. At the end of the first body 32 on the second body 33 side, a cylindrical first cylindrical portion 321 is provided. In addition, a cylindrical second tube portion 322 having an outer diameter larger than that of the first tube portion 321 and an inner diameter equal to that of the first tube portion 321 is provided at the center of the first body 32. The tube portion 321 is provided continuously. Further, in the first body 32, a cylindrical shape whose outer diameter is larger than that of the second cylinder part 322 and whose inner diameter is the same as that of the second cylinder part 322 is provided at the end opposite to the first cylinder part 321. The third cylinder part 323 is provided continuously to the second cylinder part 322.

  In the first body 32 configured as described above, a first body side stepped portion 322a is formed by the end surface of the second cylindrical portion 322 on the first cylindrical portion 321 side. In addition, an engagement flange 34 is formed over the entire circumference of the outer peripheral surface of the casing 31 at the edge of the first body 32 opposite to the second cylinder 322 side of the third cylinder 323. The joint portion 34 can be engaged with the engagement recess 15 d of the mounting hole 15.

  On the other hand, at the end of the second body 33 on the first body 32 side, a cylindrical first tube portion 331 is provided, and the first tube portion 331 has a second tube with an inner diameter of the first body 32. The outer diameter of the portion 322 is larger. In addition, a cylindrical second tube portion 332 having an inner diameter smaller than that of the first tube portion 331 is provided continuously to the first tube portion 331 at the center of the second body 33. Furthermore, a fitting recess 332 b is formed on the end surface of the second cylinder portion 332 on the first body 32 side over the entire circumference of the second cylinder portion 332. In the second body 33, a second body side step 332a is formed on the end surface of the second cylinder 332 located between the first cylinder 331 and the fitting recess 332b. Further, a locking step portion 36 is formed on the outer peripheral surface of the second body 33.

  The first body side step 322a of the first body 32 and the second body side step 332a of the second body 33 are welded by ultrasonic welding to form the welded portion 50, and the first body 32 The casing 31 is formed by welding the second body 33. In the casing 31, the first tube portion 321 of the first body 32 is fitted with the fitting recess 332 b of the second body 33. Further, the first cylinder portion 331 of the second body 33 is positioned on the outer peripheral side of the second cylinder portion 322 in the first body 32. Furthermore, an end surface 332 c of the second cylinder portion 332 in the second body 33 is positioned on the inner peripheral side of the first cylinder portion 321 in the first body 32. Further, in the casing 31, there is a gap across the entire circumference of the casing 31 between the outer peripheral surface of the first cylindrical portion 321 in the first body 32 and the inner peripheral surface of the fitting recess 332 b facing the outer peripheral surface. Is formed. And this clearance gap becomes the accommodating part 51 in which the molten resin generate | occur | produced in the case of ultrasonic welding is accommodated.

  In the relief valve 30 provided with the casing 31, the second body 33 side is inserted into the mounting hole 15 from the large diameter portion 15 a side. The relief valve 30 is inserted into the mounting hole 15 until the locking step portion 36 is locked to the locking step 15c, and the engagement flange portion 34 is engaged with the engagement recess 15d. The relief valve 30 is mounted in a state where movement of the mounting hole 15 in the axial direction is prevented by the engagement between the engagement flange 34 and the engagement recess 15d. Therefore, the relief valve 30 is mounted in the mounting hole 15 so that the first body 32 side is positioned on the discharge chamber Da side and the second body 33 side is positioned on the atmosphere side.

  In the relief valve 30, a valve chamber 37 is formed in the casing 31. A refrigerant gas inflow port 38 is formed at one end in the axial direction of the casing 31 on the discharge chamber Da side end surface (one end surface) of the first body 32, and the inflow port 38 connects the discharge chamber Da and the valve chamber 37. Communicate. In the casing 31, a cylindrical valve seat 39 is erected around the inflow port 38 toward the inside of the valve chamber 37. In order to accurately mold the valve seat 39 during the injection molding of the first body 32, the mold for molding the inside of the first body 32 can be extracted from the first body 32. It is preferable to be as short as possible. Shortening the drawing length means shortening the distance between the valve seat 39 and the first body side stepped portion 322a. Therefore, in this embodiment, the first body 32 and the second body 33 are divided. The position of the welded portion 50 is substantially the center of the casing 31 in the axial direction.

  At the other end in the axial direction of the casing 31, a refrigerant gas discharge port 45 is formed at the end surface (the other end surface) of the second body 33 on the atmosphere side, and the discharge port 45 communicates the valve chamber 37 with the atmosphere. Yes. Moreover, in the casing 31, the periphery of the discharge port 45 is a stopper portion 33a.

  In the valve chamber 37, a valve body 40 and a compression spring 44 including a coil spring are accommodated. The valve body 40 has a substantially cylindrical shape and is made of a thermoplastic resin (for example, polybutylene terephthalate resin) that is different from the thermoplastic resin that forms the first body 32 and the second body 33. A seal rubber 41 is attached to the end face of the valve body 40 on the valve seat 39 side. Further, a gas passage 37 a is formed between the peripheral surface of the valve body 40 and the inner peripheral surface of the first body 32 facing the peripheral surface, and the valve body 40 is in contact with and away from the valve seat 39. It is possible to move to. And the valve body 40 opens and closes the inflow port 38 by contacting / separating with respect to the valve seat 39. FIG. In order to smoothly move the valve body 40 in the valve chamber 37, the inner surface of the valve chamber 37 in which the outer peripheral surface of the valve body 40 may slide within the movable range of the valve body 40. Further, it is preferable that the welded portion 50 (joint surface) between the first body 32 and the second body 33 is not exposed. Therefore, in the present embodiment, the valve body 40 is moved only inside the first body 32 in order to move the valve body 40 in the valve chamber 37 where the welding portion 50 is not exposed. Therefore, an end surface 332 c that restricts unnecessary movement of the valve body 40 to the atmosphere side is disposed in the first body 32, and the welded portion 50 that is a division position of the first body 32 and the second body 33. Is arranged at the approximate center in the axial direction of the casing 31 and on the outer peripheral side of the end face 332c.

  Further, in the valve body 40, a guide groove 40c for guiding the compression spring 44 is recessed in the central portion of the end face facing the end face where the seal rubber 41 is mounted. A plurality of cutouts 40d are formed on the end surface of the valve body 40 on which the seal rubber 41 is attached and the end surface facing away from the end surface. In the valve chamber 37, one end side of the compression spring 44 is accommodated in the guide groove 40c of the valve body 40, one end of the compression spring 44 abuts on the bottom surface of the guide groove 40c, and the other end of the compression spring 44 is Abutting against the stopper portion 33 a of the casing 31. The compression spring 44 biases the valve body 40 toward the valve seat 39 in the direction of closing the inflow port 38.

  The other end of the casing 31 is in contact with the contact portion 15 e of the mounting hole 15. Also, the end surface of the first body 32 on the second tube portion 322 side of the third tube portion 323 and the end surface of the second body 33 opposite to the side where the locking step portion 36 of the first tube portion 331 is formed. Between the two, a seal member 42 is interposed. Note that the sealing member 42 prevents the refrigerant gas in the discharge chamber Da from reaching the welding portion 50.

  Therefore, the welding part 50 which is the division | segmentation position of the 1st body 32 and the 2nd body 33 in this embodiment forms the valve seat 39 accurately, makes the movement of the valve body 40 smooth, and a welding part. In order to satisfy all that 50 is located on the atmosphere side of the seal member 42, the casing 31 is substantially in the center in the axial direction.

  Next, the function of the relief valve 30 configured as described above will be described. Now, unless the inside of the discharge chamber Da of the refrigerant compressor 11 is abnormally high, the force in the valve opening direction acting on the valve body 40 based on the pressure in the discharge chamber Da is small. Therefore, the spring force of the compression spring 44 is dominant in positioning the valve body 40, and the valve body 40 is in contact with the valve seat 39. Therefore, the communication between the inlet 38 and the valve chamber 37 is not blocked by the valve body 40, and the refrigerant gas in the discharge chamber Da is not released from the relief valve 30 to the atmosphere.

  From this state, if the inside of the discharge chamber Da tries to rise to an abnormally high pressure for some reason, the force in the valve opening direction acting on the valve body 40 based on the pressure in the discharge chamber Da becomes excessive. Therefore, the valve body 40 moves against the spring force of the compression spring 44 and moves away from the valve seat 39. The valve body 40 separated from the valve seat 39 is in contact with the end surface 332 c of the second cylindrical portion 332 in the second body 33, so that the movement of the valve body 40 is restricted. Therefore, the communication between the inlet 38 and the valve chamber 37 is opened by the valve body 40, and the refrigerant gas in the discharge chamber Da passes through the inlet 38, the valve chamber 37, the gas passage 37 a, the notch 40 d and the outlet 45. It is discharged into the atmosphere, and an abnormal pressure rise in the discharge chamber Da is prevented. The position of the end surface 332c is that the valve body 40 is separated from the valve seat 39, and the refrigerant gas in the discharge chamber Da flows into the valve chamber 37 by a flow rate sufficient to prevent an abnormal pressure increase in the discharge chamber Da. It is a position that satisfies the required opening.

  The relief valve 30 is manufactured as follows. The first body 32 and the second body 33 are assembled in a state where the valve body 40 and the compression spring 44 are accommodated in the first body 32, and an ultrasonic vibration source (for example, a horn) (not shown) is attached to the second body 33. Ultrasonic vibration is transmitted to the first body 32 and the second body 33 by being applied to the end surface on the axial direction side. Then, due to this ultrasonic vibration, intensive expansion and contraction motion occurs on the contact surfaces of the first body side step 322a and the second body side step 332a, which are contact surfaces of the first body 32 and the second body 33. At the same time, frictional heat due to ultrasonic vibration is generated on the contact surface between the first body side step 322a and the second body side step 332a. And while the contact surface of the 1st body side step part 322a and the 2nd body side step part 332a fuse | melts, the contact surfaces of the 1st body side step part 322a and the 2nd body side step part 332a join. Therefore, the first body 32 and the second body 33 are welded by ultrasonic welding to form the welded portion 50, and the relief valve 30 is manufactured. The melted molten resin flows out to the storage unit 51 and is stored in the storage unit 51.

In the above embodiment, the following effects can be obtained.
(1) The first body 32 and the second body 33 are made of the same material thermoplastic resin (polyetherimide resin), and the valve body 40 is a thermoplastic resin that forms the first body 32 and the second body 33. It consists of a thermoplastic resin (polybutylene terephthalate resin) of a different material. When the first body 32 and the second body 33 are welded by ultrasonic welding, the first body 32 and the second body 33 are vibrated by ultrasonic vibration, and the valve body 40 in the casing 31 is also vibrated. And the 1st body 32 and the valve body 40 will contact. Here, ultrasonic welding has the property of melting and joining materials of the same material. However, the first body 32 and the valve body 40 are made of different thermoplastic materials (polyetherimide resin and polybutylene terephthalate resin). Therefore, when the first body 32 and the second body 33 are welded by ultrasonic welding, even if the first body 32 and the valve body 40 are contacted by ultrasonic vibration, the first body 32 and the valve body 40 are The first body 32 and the valve body 40 are not welded to each other without melting. As a result, it is possible to prevent the valve body 40 from moving in the casing 31.

  (2) The valve body 40 is made of a thermoplastic resin (polybutylene terephthalate resin) made of a material different from the thermoplastic resin forming the first body 32 and the second body 33. Therefore, compared with the case where the valve body 40 is made of a material such as metal or ceramic, for example, the valve body 40 can be easily processed and the valve body 40 can be reduced in weight.

  (3) The valve body 40 separated from the valve seat 39 comes into contact with the end surface 332 c of the second cylindrical portion 332 in the second body 33. Therefore, unnecessary movement of the valve body 40 to the atmosphere side is restricted, and when the valve body 40 that has been opened returns to the position of the valve seat 39 by the biasing force that acts on the inlet 38 side of the compression spring 44, It can suppress that the valve body 40 returns to the position of the valve seat 39, tilting.

In addition, you may change the said embodiment as follows.
In embodiment, the material of the valve body 40 is good also as materials, such as a metal or a ceramic, for example.

In the embodiment, the material of the valve body 40 may be a synthetic resin different from the polybutylene terephthalate resin.
In embodiment, the material of the 1st body 32 and the 2nd body 33 is good also as resin different from polyetherimide resin.

  The present invention has been embodied in the refrigerant compressor 10 in the refrigerant circuit 10 of the vehicle air conditioner. However, the present invention is not limited to this. For example, the relief valve 30 is used as a refrigerant circuit of an air conditioner other than the vehicle air conditioner. You may equip with the compressor used for the compressor used for refrigerant circuits other than an air conditioner, and equipment (for example, hydraulic pumps) other than a compressor.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) The relief valve according to claim 1, wherein the valve body is made of a resin material that is different from a resin material forming the first body and the second body.

(A) is the schematic which shows a refrigerant circuit, (b) is sectional drawing which shows the relief valve in a mounting hole.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 30 ... Relief valve, 31 ... Casing, 32 ... 1st body, 33 ... 2nd body, 38 ... Inflow port, 40 ... Valve body, 45 ... Release port.

Claims (1)

A resin material first body in which a gas inlet is formed and a resin material second body in which a gas outlet is formed are welded by ultrasonic welding, and the inlet is provided. A relief valve that houses a valve body that opens and closes inside the casing,
The first body and the second body are made of the same resin material, and the valve body is made of a material different from the resin material forming the first body and the second body. Relief valve.

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