JP2022057185A - Seal for flow rate control valve and flow rate control valve device - Google Patents

Abstract

To provide a seal or the like for a flow rate control valve which can be inexpensively manufactured, is suppressed in the wear damage of a slide-contacting rotor, and excellent in low leak performance, low friction performance, and low wear performance.SOLUTION: A seal 6 for an annular flow rate control valve which is used in a flow rate control valve device 1 having a housing 2 having an introduction part 5 for receiving cooling water, and a resin-made rotor 4 arranged in the housing 2, having a spherical or cylindrical external peripheral face, and rotating with respect to the housing 2. The seal 6 for the annular flow rate control valve which is arranged between the rotor 4 and the introduction part 5 in the housing 2, and slide-contacts with the external peripheral face 4a of the rotor 4. The seal 6 is a molding composed of a fluorine resin composition, a cross section shape of a seal face 6a of the seal 6 which slide-contacts with the rotor 4 is formed into a substantially-semi circular shape, and a part of the seal face 6a line-contacts with the rotor 4.SELECTED DRAWING: Figure 1

Description

The present invention provides a flow control valve seal used in a flow control valve device that adjusts the flow rate and flow path of cooling water from an internal combustion engine, and a seal thereof, in order to improve fuel efficiency by increasing the thermal efficiency of the automobile. The present invention relates to a flow control valve device.

Conventionally, an automobile is provided with a circulation flow path for circulating cooling water to cool an engine. The circulation flow path has a plurality of flow paths such as a flow path for circulating the cooling water to the radiator and a flow path for circulating the cooling water to the heater core of the air conditioner. A flow rate control valve device for controlling the flow rate of the cooling water is arranged in the circulation flow path, and the flow rate of the cooling water in each flow path is adjusted by this valve device.

As a flow control valve device, for example, Patent Document 1 has an introduction port for receiving cooling water from an internal combustion engine, a housing having a discharge portion protruding to send out cooling water, and a wall portion having a spherical outer surface. A flow control valve device that includes a rotor that rotates around a rotating shaft core that extends perpendicular to the introduction port inside the housing, and an annular seal that is provided at the discharge section and is in sliding contact with the outer surface of the rotor. Is disclosed. This Patent Document 1 describes that a thermoplastic resin such as polytetrafluoroethylene (PTFE) resin can be used as the material of the annular seal.

Patent Document 2 proposes an electric water valve using a sealing member having a circumferential main lip located inside and a circumferential auxiliary lip concentric with the main lip and located outside. There is. It is described that this sealing member is made of a rubber material and an elastic synthetic resin material, and that a coating layer of a fluororesin sheet such as PTFE is formed on the friction surface for the purpose of reducing friction.

Japanese Unexamined Patent Publication No. 2016-188693 Japanese Unexamined Patent Publication No. 2015-218775

In recent years, as fuel efficiency regulations for automobiles have become stricter, the installation of flow control valve devices that adjust the flow rate and flow path of cooling water from internal combustion engines has been promoted in order to improve fuel efficiency by increasing thermal efficiency. There is. As in Patent Document 1, PTFE resin is used for the annular seal used in this device, but there is room for improvement in terms of seal durability and cost. Further, since the PTFE resin has a high melt viscosity and is difficult to be injection molded, machining is required to form an annular seal having a complicated shape, resulting in high cost. In addition, there is an increasing demand for improving the sealing performance of the cooling water and reducing the frictional resistance with the rotor as the mating material.

Patent Document 2 states that a seal member made of an elastic synthetic resin material such as a rubber material can be coated with a fluororesin sheet such as PTFE, but a specific method for fixing the fluororesin sheet to the seal member is Not mentioned.

The present invention has been made in view of such circumstances, and is a seal for a flow control valve which can be manufactured at low cost, has less wear damage to the rotor in sliding contact, and is excellent in low leak property, low friction property, and low wear property. And to provide a flow control valve device with its seal.

The seal for a flow control valve of the present invention (hereinafter, also simply referred to as “seal”) is provided inside a housing having an introduction portion for receiving cooling water and a discharge portion for delivering cooling water, and is spherical. Alternatively, it is used in a flow control valve device having a cylindrical outer peripheral surface and having a rotor made of resin that rotates with respect to the housing, and is used in the housing between the rotor and the introduction portion or the discharge portion. An annular flow rate control valve seal that is provided in the rotor and is in sliding contact with the outer peripheral surface of the rotor. The flow rate control valve seal is a molded body made of a fluororesin composition and is in sliding contact with the rotor. The axial cross-sectional shape of the sealing surface of the valve seal is substantially semicircular, and a part of the sealing surface is in line contact with the rotor.

When the radial thickness of the flow control valve seal is L and the axial cross-sectional shape of the seal surface is a substantially semicircular radius R, the mathematical formula R = 0.5L to L is satisfied. It is a feature.

The introduction portion or the discharge portion is cylindrical, and the flow control valve seal is mounted on the inner diameter side or the outer diameter side of the introduction portion or the discharge portion.

A protrusion is provided on the outer diameter side of the introduction portion or the discharge portion, and when the seal for the flow rate control valve is attached, the inner diameter surface of the seal is deformed, so that the introduction portion or the discharge portion is formed. It is characterized in that the seal for the flow rate control valve is coupled.

The introduction portion or the discharge portion is an injection molded product of a polyphenylene sulfide resin composition or a semi-aromatic polyamide resin composition.

The fluororesin composition is characterized by containing 3 to 30% by volume of a non-fibrous filler with respect to the entire composition, the balance being a fluororesin, and no fibrous filler.

The flow control valve device of the present invention has a housing having an introduction portion for receiving cooling water and a discharge portion for delivering cooling water, and a spherical or cylindrical outer peripheral surface provided inside the housing. A resin rotor that rotates with respect to the rotor and an annular flow control valve seal that is provided between the rotor and the introduction portion or the discharge portion in the housing and is in sliding contact with the outer peripheral surface of the rotor. The flow control valve device provided, wherein the rotor is an injection molded body of a polyphenylene sulfide resin composition, and the seal for the flow control valve is a molded body made of a fluororesin composition, and the flow rate is in sliding contact with the rotor. The cross-sectional shape of the sealing surface of the control valve seal in the axial direction is substantially semicircular, and a part of the sealing surface is in line contact with the rotor.

Since the seal for the flow rate control valve of the present invention is a molded body made of a fluororesin composition, it is excellent in alkali resistance and low water absorption, and deterioration of the resin can be suppressed even in an environment in contact with cooling water. As a result, it can be manufactured at low cost, and there is little wear damage to the rotor that is in sliding contact, and it is excellent in low leakage and low friction. Further, the seal of the present invention has a substantially semicircular cross-sectional shape in the axial direction of the seal surface of the flow control valve seal that is in sliding contact with the rotor, and a part of the seal surface is in line contact with the rotor. It has a small contact area, excellent low friction, and low torque.

Further, the shape of the seal can be made as simple as possible, and the seal unit of a desired design can be obtained by giving the introduction portion or the discharge portion a degree of freedom in shape as an injection molded body. As a result, it is not always necessary to make the seal itself into a complicated shape. Further, by simplifying the seal shape, even if the fluororesin composition is a PTFE resin that cannot be injection molded, the seal can be manufactured by automatic molding, and the cost is reduced.

When the radial thickness of the flow control valve seal is L and the axial cross-sectional shape of the seal surface is a substantially semicircular radius R, the formula R = 0.5L to L is satisfied. While maintaining the line contact between a part of the rotor and the rotor, the close contact between the rotor and the seal is also maintained. This results in excellent low friction and low torque.

Since the introduction part or the discharge part is cylindrical and the flow control valve seal is attached to the inner diameter side or the outer diameter side of the introduction part or the discharge part, the contact area between the introduction part or the discharge part and the seal increases. Excellent for low leakage.

A protrusion is provided on the outer diameter side of the introduction part or the discharge part, and when the flow control valve seal is attached, the inner diameter surface of the seal is deformed, so that the introduction part or the discharge part and the flow control valve seal are provided. Is bonded, so it becomes a unit that is firmly bonded (hereinafter referred to as a seal unit). Therefore, when the inner diameter surface of the seal is restrained by the protrusion and sliding occurs between the seal surface and the outer peripheral surface of the rotor, rattling is less likely to occur. In addition, the sealing surface is difficult to rotate in the rotation direction of the rotor. Further, it is possible to improve the sealing property not only between the seal and the rotor but also between the seal and the introduction portion or the discharge portion. As a result, the low leakage property is further excellent.

Since the introduction part or the discharge part is an injection molded product of a polyphenylene sulfide resin composition or a semi-aromatic polyamide resin composition, it is excellent in heat resistance, alkali resistance, water absorption and the like, and low leakage property is maintained for a longer period of time.

Since the fluororesin composition contains 3 to 30% by volume of the non-fibrous filler with respect to the entire composition, the balance is the fluororesin, and the fibrous filler is not contained, the mating material with which the sealing material comes into contact is Even if the rotor is made of resin, it is less likely to wear and damage the rotor, and is excellent in low friction and low wear.

In the flow control valve device of the present invention, the rotor is an injection molded body of a polyphenylene sulfide resin composition, and the seal for the flow control valve is a molded body made of a fluororesin composition, so that the seal and the rotor are different resin materials. It will slide between each other. Therefore, it is possible to prevent an increase in wear due to a high friction coefficient, which is a concern in sliding between the same resin materials, and low friction and low wear can be obtained. Further, in the flow control valve device, the cross-sectional shape of the seal surface of the flow control valve seal that is in sliding contact with the rotor in the axial direction is substantially semicircular, and a part of the seal surface is in line contact with the rotor. It has a small contact area, excellent low friction, and low torque.

It is sectional drawing of the main part at the time of opening a valve of the flow rate control valve device of this invention. It is sectional drawing of an example of the seal for a flow rate control valve of this invention. It is sectional drawing of an example of the introduction part in the flow rate control valve device of this invention. It is sectional drawing of an example of the seal unit which combined the seal for the flow rate control valve of this invention, and the introduction part. It is sectional drawing of the seal for the flow rate control valve of the comparative example 1. FIG.

An example of a valve device to which the seal for a flow rate control valve of the present invention is applied will be described with reference to FIG. As shown in FIG. 1, the valve device 1 includes a housing 2, a rotating shaft 3 rotatably supported with respect to the housing 2, and a rotor 4 housed in the housing 2 and rotated integrally with the rotating shaft 3. , A seal 6 that is in sliding contact with the outer peripheral surface 4a of the rotor 4 is provided. The housing 2 is provided with an introduction unit 5 that receives the cooling water from the engine and a discharge unit (not shown) that sends the cooling water to each device such as a radiator. A fixing seal such as an O-ring is provided between the introduction portion 5 and the housing 2. FIG. 1 is a cross-sectional view of a main part of the valve device 1 on the introduction portion side. The rotating shaft 3 is connected to a motor (not shown).

A protrusion is provided on the outer diameter side of the rotor side end of the introduction portion 5. The seal 6 is attached to the rotor side end of the introduction portion 5 by means such as press fitting, and is inscribed in the outer diameter side of the introduction portion. As a result, the contact area between the introduction portion or the discharge portion and the seal is increased, and the low leakage property is excellent. A part of the sealing surface 6a of the seal 6 is pressed toward the outer peripheral surface 4a of the rotor 4 and is in line contact with the outer peripheral surface 4a of the rotor 4. This close contact state can prevent leakage of cooling water.

The rotor 4 is a spherical rotating rotor having a hollow portion inside, and the outer peripheral surface 4a in sliding contact with the seal 6 is formed in a convex spherical shape. The rotor 4 has a rotor opening 4b penetrating inside and outside, and the seal 6 has a seal opening penetrating the center. The rotation shaft 3 rotates in the direction of the arrow, and the rotor 4 also rotates accordingly. Due to the rotation, the rotor opening 4b and the seal opening communicate with each other to open the valve, and the rotor opening 4b and the seal opening do not communicate with each other to close the valve. In the valve open state of FIG. 1, the cooling water flowing in the direction of the black arrow is supplied into the rotor 4. In this way, by rotating the rotor 4, the valve opening and closing of the valve device 1 can be controlled, whereby the flow rate adjustment and the distribution adjustment of the cooling water are performed.

The rotor 4 is made of resin, and is, for example, an injection molded product of a resin composition using a thermoplastic resin as a base resin. The thermoplastic resin is not particularly limited, but it is preferable to use a thermoplastic resin other than the fluororesin, for example, PPS resin, polyamide 66 (PA66) resin, semi-aromatic PA resin, polyetheretherketone (PEEK) resin. Etc. can be used. As the semi-aromatic PA resin, a polyamide 9T resin and a polyamide 10T resin having a small water absorption rate are preferable. Among these resins, PPS resin, which has low water absorption, is excellent in heat resistance and alkali resistance, and is inexpensive, is more preferable.

Further, it is preferable to add glass fiber to the resin composition used for the rotor 4 in order to obtain high strength, high elasticity and high dimensional accuracy. The PPS resin containing glass fiber is more preferable because it has excellent high strength and high elasticity. When the glass fiber is blended, the blending amount thereof is 10 to 50% by mass, preferably 20 to 40% by mass, based on the entire resin composition. If the amount of glass fiber is more than the predetermined amount, the seal will be worn and damaged, and if it is less than the predetermined amount, sufficient strength cannot be obtained. In addition, additives such as inorganic substances can be added to this resin composition in order to eliminate anisotropy and improve dimensional accuracy.

The introduction portion 5 is made of resin, and is, for example, an injection-molded article having a cylindrical shape of a resin composition using a thermoplastic resin as a base resin. By using an injection molded body, it is possible to handle complicated shapes. The thermoplastic resin is not particularly limited, and for example, a PPS resin, a polyamide 66 (PA66) resin, a semi-aromatic PA resin, a polyetheretherketone (PEEK) resin, and the like can be used. As the semi-aromatic PA resin, a polyamide 9T resin and a polyamide 10T resin having a small water absorption rate are preferable. Among these resins, PPS resin, which has low water absorption, is excellent in heat resistance and alkali resistance, and is inexpensive, is more preferable.

Although FIG. 1 shows the configuration on the introduction portion side, the basic configuration on the discharge portion side is the same. Specifically, a seal is provided between the rotor 4 and the cylindrical discharge portion (not shown) in the housing 2, and the seal is pressed toward the rotor 4 to the outer peripheral surface 4a. It is in close contact. This seal has the same shape and material as the seal 6 of FIG. The discharge unit is provided in the housing 2 at a position (for example, a position opposite to the introduction unit 5 in FIG. 1) at a predetermined distance from the introduction unit 5 in the circumferential direction in which the rotor 4 rotates.

An example of the seal for the flow rate control valve of the present invention will be described with reference to FIG. FIG. 2 is an axial sectional view of the seal. As shown in FIG. 2, the seal 6 has a substantially cylindrical shape, and is composed of a cylindrical portion 6b that is coupled to the introduction portion 5 (see FIG. 1) and a seal portion 6c having a sealing surface 6a that makes line contact with the rotor. To. The sealing surface 6a has a substantially semicircular cross-sectional shape in the axial direction and has a predetermined radius of curvature. Hereinafter, the radius of curvature is also referred to as a radius. Assuming that the radial thickness of the cylindrical portion 6b of the seal 6 is L, the radius R of the semicircle of the seal surface 6a can be arbitrarily set as long as it is 0.5 L or more. As R, for example, it is preferable to satisfy the mathematical formula R = 0.5L to L. When R> L, the contact area between the sealing surface and the outer peripheral surface of the rotor becomes large, and the torque may increase.

The seal surface and the outer peripheral surface of the rotor have a predetermined width in the radial direction at a portion where the seal is elastically deformed and is in line contact with each other. The line contact portion is a narrow annular shape, and the radial width is preferably 0.01 to 1.00 mm, for example. Since the width of the line contact portion is in the range of 0.01 to 1.00 mm, the contact area is small with respect to the entire sealing surface, so that low torque is maintained and low leakage is also excellent. The width of the line contact portion is more preferably 0.05 to 0.5 mm, further preferably 0.1 to 0.5 mm.

As described above, the introduction portion 5 shown in FIG. 3 is provided with a protrusion 5a on the outer diameter side thereof. Specifically, the protrusion 5a is provided at the rotor side end of the introduction portion 5. When the seal is attached by means such as press-fitting so as to inscribe the outer diameter side of the rotor side end of the introduction portion 5, pressure is applied from the protrusion 5a to the inner diameter surface of the seal to cause deformation, and the introduction portion is deformed. 5 and the seal can be firmly bonded. The protrusion 5a may be provided over the entire circumference of the outer diameter side of the rotor side end portion of the introduction portion 5, and may be provided on the circumference of the outer diameter surface of the rotor side end portion at predetermined intervals in the axial direction. It may be provided in several places. In order to improve the sealing property between the seal and the introduction portion 5, it is preferable that the protrusion 5a is provided over the entire circumference. The radial height h of the protrusion is not necessarily limited, but is preferably 0.2 to 1 mm, more preferably 0.3 to 0.7 mm. If it exceeds 1 mm, the deformation of the seal becomes excessive and there is a risk of breakage.

The protrusion 5a can be easily provided on the outer diameter side of the introduction portion at the time of injection molding. By attaching a seal to this introduction portion, as described above, the introduction portion 5 and the seal are firmly bonded to each other to form a seal unit. Therefore, by simplifying the shape of the seal as much as possible and taking advantage of the degree of freedom in the shape of the introduction portion, the seal unit can be made into a desired design.

By connecting the seal and the introduction portion, the seal unit 7 shown in FIG. 4 can be obtained. In the seal unit 7, since the inner diameter surface of the seal 6 is restrained by the protrusion 5a, rattling is less likely to occur when sliding occurs between the seal surface 6a and the outer peripheral surface of the rotor. Further, the sealing surface 6a is difficult to rotate in the rotation direction of the rotor.

When opening and closing the valve device, the rotor rotates with the seal pressed. Since the seal is fixed and the seal surface is always in sliding contact with the outer peripheral surface of the rotor, wear is more likely to proceed than the outer peripheral surface of the rotor. Further, since the seal needs to be in close contact with the curved surface shape of the rotor, appropriate deformability is required. Further, since an aqueous solution (antifreeze) of PH7 to 11 containing ethylene glycol or the like as a main component is generally used for the cooling water, the seal 6 in contact with the cooling water has alkali resistance and low water absorption. Desired.

Since the fluororesin composition used for the seal for the flow control valve of the present invention has low elasticity and low hardness, it is easily deformed along the curved (spherical or cylindrical) outer peripheral surface of the resin rotor and is sealed. Cheap. Further, the fluororesin is excellent in alkali resistance and low water absorption, and deterioration of the resin can be suppressed even in an environment where it comes into contact with cooling water. As a result, it can be manufactured at low cost, and there is little wear damage to the rotor that is in sliding contact, and it is excellent in low leakage and low friction.

Fluororesin is easily worn by itself, but wear resistance can be improved by blending an appropriate filler. Since the fluororesin composition of the present invention contains a non-fibrous filler and does not contain a fibrous filler, the resin rotor as a mating material is less likely to be abraded and damaged, and low friction and low wear characteristics can be obtained.

Seals include PTFE resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) resin, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, tetrafluoroethylene-ethylene copolymer (ETFE) resin, etc. It is a molded body of a fluororesin composition based on a fluororesin typified by. As the fluororesin composition, especially when it is based on PTFE resin, the seal has low elasticity and low hardness, so that it is easily deformed along the curved (spherical or cylindrical) outer peripheral surface of the resin rotor. It is preferable because it is easy to seal.

The molding method is not particularly limited, and injection molding, extrusion molding, automatic molding and the like can be adopted. By simplifying the shape of the seal, even if the above-mentioned fluororesin is a PTFE resin that is difficult to be injection-molded, the seal can be manufactured by automatic molding, and the cost is reduced. In the automatic molding referred to here, the powder of the PTFE resin composition whose fluidity as a powder is enhanced by granulation is put into a press die, a large number of premolded bodies are produced at room temperature in a high cycle, and then PTFE is formed. It refers to a manufacturing method in which a calcined product is obtained by heat-treating it at a temperature equal to or higher than the melting point of the resin. As the granulation method of the PTFE resin composition, either dry granulation or wet granulation may be used. In the case of automatic molding, if ungranulated powder is used as it is, the fluidity of the powder is poor and it becomes difficult to uniformly fill the mold.

When molding PFA resin, FEP resin, ETFE resin, etc., for example, the raw materials are dry-mixed with a Henshell mixer, ball mixer, ribbon blender, Ladyge mixer, Ultra Henshell mixer, etc., and then a twin-screw extruder, etc. After melt-kneading with a melt extruder to obtain molding pellets, molding can be performed by injection molding.

The molecular structure of the PTFE resin is represented by-(CF ₂ -CF ₂ ) n- (n is an integer), and molding powder produced by suspension polymerization, fine powder produced by emulsion polymerization, and the like can be used. The molding powder produced by suspension polymerization has a higher molecular weight than the fine powder produced by emulsion polymerization, and is more preferable from the viewpoint of wear resistance.

Further, the base resin of the fluororesin composition of the present invention includes a general PTFE resin and a perfluoroalkyl ether group (-CpF ₂ p-O-) (p is an integer of 1-4) or a polyfluoroalkyl group (H). A modified PTFE resin into which (CF ₂ ) q-) (q is an integer of 1-20) or the like can also be used.

In order to improve the frictional wear characteristics in the cooling water, it is preferable to add a filler resistant to the alkaline aqueous solution of PH7 to 11 to the fluororesin composition. Examples of the filler include carbon fiber, graphite, PTFE resin, inorganic substances (mica, talc, calcium carbonate, etc.), whiskers (calcium carbonate, potassium titanate, etc.) and the like. Among these fillers, it is preferable to use a non-fibrous filler, and in this case, it is more preferable not to contain the fibrous filler from the viewpoint of aggression to the rotor as the mating material.

The non-fibrous filler may be any other than the fibrous filler having an aspect ratio such as carbon fiber, glass fiber, and whisker, and examples thereof include amorphous granular, spherical, scaly, and plate-shaped fillers. Among these, granular and spherical fillers having no anisotropy are preferable.

Graphite is preferably used as the non-fibrous filler. Graphite has the effect of imparting low friction and low wear characteristics in cooling water. Although scaly, granular or spherical graphite can be used, it is more preferable to use granular graphite or spheroidal graphite which does not increase the elastic modulus of the fluororesin composition. The average particle size of graphite is not limited, but is preferably 3 to 50 μm, more preferably 10 to 30 μm. If it exceeds 50 μm, the tensile elongation property of the fluororesin composition deteriorates. The average particle size can be measured by using, for example, a particle size distribution measuring device using a laser light scattering method or the like. The seal made of a fluororesin composition in which graphite is blended with the above-mentioned base resin is less likely to wear and damage the resin rotor, and stable sealing properties can be obtained for a long period of time. In addition, since it has excellent alkali resistance, it can be used for a long time without deterioration.

When a PFA resin, which is a molten fluororesin, a FEP resin, or an ETFE resin is used as the base resin of the fluororesin composition, a PTFE resin may be blended as a filler. The average particle size of the PTFE resin is not particularly limited, but is preferably 10 to 50 μm.

A well-known resin additive may be added to the fluororesin composition to the extent that the effect of the present invention is not impaired. Examples of this additive include friction property improving agents such as boron nitride, molybdenum disulfide, and tungsten disulfide, and colorants such as carbon powder, iron oxide, and titanium oxide.

The resin composition used for the seal of the present invention contains 70 to 100% by volume of the above-mentioned base resin with respect to the entire resin composition. When the filler is blended in the resin composition, a composition in which the filler is 3 to 30% by volume and the balance is the base resin is preferable, and a composition in which the filler is 5 to 20% by volume and the balance is the fluororesin is more preferable. preferable. As the filler, it is preferable to use a non-fibrous filler. If the filler exceeds 30% by volume, the tensile elongation characteristics of the fluororesin composition may deteriorate.

In the flow control valve device of the present invention, the seal for the flow control valve is a molded body of a fluororesin composition, and the rotor is an injection molded body of a PPS resin composition. Therefore, the seal and the rotor are made of different resin materials. It becomes sliding. Therefore, it is possible to prevent an increase in wear due to a high friction coefficient that is expected in sliding between the same resin materials, and good low friction and low wear can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. The configurations of the resin compositions of Examples and Comparative Examples and the results of the wear test are shown in Table 2.

Examples 1 to 4 and Comparative Example 1
An annular preformed body was prepared by automatic molding using the PTFE resin composition blended in the blending ratio (% by volume) shown in Table 2. The fired body obtained by heat-treating this preformed body was used in an experiment as a seal for a flow control valve. There are two types of seal shapes: the shape of the seal 6 of the present invention shown in FIG. 2 (Examples 1 to 4) and the shape of the seal 8 shown in FIG. 5 (Comparative Example 1). In the case of FIG. 2, there are two types of relationships between R and L, one is when R = 0.5L and the other is when R = L.

The raw materials used for the PTFE resin composition are shown below.
(1) PTFE
Mitsui Chemours Fluoro Products Co., Ltd .: Teflon (registered trademark) 7-J
(2) Graphite Nippon Graphite Industry Co., Ltd .: CGB-20 (average particle size: 20 μm)
(3) Glass fiber Asahi Fiber Glass Co., Ltd .: MF06MB120

Using the various seals produced, a frictional wear test with a spherical rotor (PPS resin composition containing 40% by mass of glass fiber) was performed. The seal is attached to the outer diameter side of a cylindrical component (PPS resin composition containing 40% by mass of glass fiber) imitating the introduction part of the flow control valve device of the present invention to form a seal unit, which is pressed against the rotor. installed. After that, the rotor was driven, a frictional wear test was performed under the test conditions shown in Table 1, the rotational torque and the amount of wear of the seal were measured, and the presence or absence of wear damage to the rotor was visually confirmed. The LLC in Table 1 is an automobile engine cooling water, and its main component is ethylene glycol.
Rotor: φ60 (outer diameter)
Seal: φ25 (outer diameter) x φ19 (inner diameter) x 4 mm (height)
Turning, surface roughness Ra 1 μm

Comparing Examples 1 to 4 having the seal shape of the present invention shown in FIG. 2, Example 1 (PTFE: 100% by volume) has a larger amount of wear than Examples 2 and 3. rice field. In Example 2 (PTFE: 95% by volume, graphite: 5% by volume) and Example 3 (PTFE: 80%, graphite: 20% by volume), both torque and wear amount showed low values, showing good results. rice field. In Example 4 (PTFE: 90% by volume, glass fiber: 10% by volume), wear damage of the rotor was observed.

Comparative Example 1 (PTFE: 95% by volume, graphite: 5% by volume) having the shape shown in FIG. 5 showed a higher torque than Example 2 having the same mixing ratio, although the amount of wear was small.

The flow rate control valve seal of the present invention can be manufactured at low cost, and has excellent wear resistance, low leakage property, low friction property, and low wear property of the rotor that is in contact with the sliding contact. Therefore, the flow rate control valve that controls the flow rate of the cooling water. Can be widely used in equipment.

1 Valve device 2 Housing 3 Rotating shaft 4 Rotor 5 Introductory part 5a Protrusion part 6, 8 Seal 7 Seal unit

Claims (7)

A housing having an introduction part for receiving cooling water and a discharge part for sending out cooling water, and a resin rotor provided inside the housing and having a spherical or cylindrical outer peripheral surface and rotating with respect to the housing. Used in flow control valve devices equipped with
An annular flow rate control valve seal provided between the rotor and the introduction portion or the discharge portion in the housing and in sliding contact with the outer peripheral surface of the rotor.
The seal for the flow rate control valve is a molded body made of a fluororesin composition.
The cross-sectional shape of the seal surface of the flow control valve seal that is in sliding contact with the rotor in the axial direction is substantially semicircular.
A seal for a flow control valve, characterized in that a part of the sealing surface is in line contact with the rotor. When the radial thickness of the flow control valve seal is L and the axial cross-sectional shape of the seal surface is a substantially semicircular radius R, the mathematical formula of R = 0.5L to L is satisfied. The seal for a flow control valve according to claim 1, wherein the seal is characterized. The introduction portion or the discharge portion is cylindrical and has a cylindrical shape.
The seal for a flow rate control valve according to claim 1 or 2, wherein the seal for the flow rate control valve is mounted on the inner diameter side or the outer diameter side of the introduction portion or the discharge portion. A protrusion is provided on the outer diameter side of the introduction portion or the discharge portion, and when the seal for the flow rate control valve is attached, the inner diameter surface of the seal is deformed to form the introduction portion or the discharge portion. The seal for a flow rate control valve according to claim 3, wherein the seal for the flow rate control valve is coupled. The flow rate control valve according to any one of claims 1 to 4, wherein the introduction portion or the discharge portion is an injection molded product of a polyphenylene sulfide resin composition or a semi-aromatic polyamide resin composition. Seal for. The fluororesin composition is characterized by containing 3 to 30% by volume of a non-fibrous filler with respect to the entire composition, the balance being a fluororesin, and no fibrous filler. The seal for a flow control valve according to any one of claims 5 and 5. A housing having an introduction part for receiving cooling water and a discharge part for sending out cooling water, and a resin rotor provided inside the housing and having a spherical or cylindrical outer peripheral surface and rotating with respect to the housing. A flow rate control valve device provided between the rotor and the introduction portion or the discharge portion in the housing and provided with an annular flow rate control valve seal that is in sliding contact with the outer peripheral surface of the rotor.
The rotor is an injection molded product of a polyphenylene sulfide resin composition.
The seal for the flow rate control valve is a molded body made of a fluororesin composition.
The cross-sectional shape of the seal surface of the flow control valve seal that is in sliding contact with the rotor in the axial direction is substantially semicircular.
A flow control valve device characterized in that a part of the sealing surface is in line contact with the rotor.

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