CN116323098A

CN116323098A - Valve seat, method of manufacturing the same, and disk valve device

Info

Publication number: CN116323098A
Application number: CN202180063730.4A
Authority: CN
Inventors: 福泽觉
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2020-09-30
Filing date: 2021-08-25
Publication date: 2023-06-23
Also published as: WO2022070694A1

Abstract

The invention provides a valve seat of a disk valve device and a disk valve device, which can reduce reject ratio and cost. The valve seat (2) of the disk valve device is made of synthetic resin, one surface of the valve seat (2) is a sliding surface sliding with the valve core, an anti-sliding surface (6) serving as the other surface is in contact with the shell through a gasket, a surface (7) in contact with the gasket in the anti-sliding surface (6) and a surface (8) around the water through hole (5) are grinding surfaces, and surfaces except the grinding surfaces in the anti-sliding surface (6) are concave surfaces (9) recessed relative to the grinding surfaces.

Description

Valve seat, method of manufacturing the same, and disk valve device

Technical Field

The present invention relates to a valve seat of a disc valve device for switching a flow path and a flow rate of a fluid, a method for manufacturing the same, and a disc valve device. Further, the present invention relates to a disk valve such as a valve seat and a valve body.

Background

A disk valve device for switching a flow path and a flow rate is used in a warm/cold water mixing faucet, a refrigerant valve device, a human body local cleaning device, and the like (patent documents 1 to 4). The valve body as a movable disk of the disk valve device is slidably disposed with respect to a valve seat as a fixed disk, and grooves and holes serving as flow paths are formed in the valve seat and the valve body.

In order to prevent fluid leakage and reduce slip torque, the sliding surfaces of the valve seat and the valve body are precisely polished. In order to facilitate the formation of complex shapes of the valve seat and the valve body and to reduce the sliding torque, injection molded articles of lubricating synthetic resin are used.

The disk valve device includes a disk valve unit including a valve seat and a valve body, and a gasket in a housing. The sliding-preventing surface, which is the surface of the valve seat opposite to the sliding surface, is pressed against and fixed to the bottom surface of the housing via a rubber gasket (hereinafter, the sliding-preventing surface is also referred to as a fixed surface). The valve seat is non-rotatably positioned within the housing. The valve seat is formed with a plurality of through holes (water passage holes) for water passage, which pass through from the sliding surface to the sliding surface. A flow path for supplying tap water to the disk valve is formed at the lower part of the housing, and the flow path and the water through hole are communicated through the hole of the gasket. Water leakage is prevented by the gasket through the valve seat and the waterway of the housing.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2001-336648

Patent document 2: japanese patent laid-open No. 2007-270863

Patent document 3: japanese patent No. 5615993

Patent document 4: japanese patent laid-open publication No. 2011-42981

Disclosure of Invention

Problems to be solved by the invention

For example, the sliding-preventing surface of the valve seat needs to be formed into a smooth surface for sealing with the gasket, but in the case where the valve seat is an injection molded article of synthetic resin, there is a possibility that the flatness is lowered due to shrinkage. The reduction in planarity due to shrinkage may be solved by grinding.

However, even if the anti-slip surface is precisely injection molded without shrinkage or finished by grinding, the synthetic resin product is easily damaged, and therefore, there is a possibility that the surface is damaged in the process until the product is completed. For example, when the surface is roughened by damage to the sliding surface, a gap is formed between the sliding surface and the gasket, and thus the sealing performance is lowered, which may cause water leakage. Therefore, the valve seat is inspected after the manufacture of the valve seat, and the valve seat with damage on the sliding surface and the sliding-preventing surface is eliminated.

In the case of the valve seat, damage to the sliding surface is a cause of water leakage, and is eliminated regardless of the degree of damage. On the other hand, it is considered that the damage of the sliding surface does not affect the sealing performance and other functions of the surface other than the surface in contact with the gasket. However, in the appearance inspection by a person, it is difficult to determine whether the surface is a portion that does not affect the function or a portion that is affected even if the surface is damaged, and when it is confirmed that the sliding surface is damaged, the valve seat is practically excluded regardless of the position. Therefore, in the conventional valve seat, it is difficult to reduce the failure rate of the valve seat due to damage.

However, in addition to the anti-slip surface (fixed surface) of the valve seat, the slip surface of the valve seat is also finished by grinding. Therefore, the polishing margins are provided on the sliding surface side and the anti-sliding surface side of the molded body (molding material) before polishing, respectively, and the thickness of the molding material is formed to be thicker than the thickness of the valve seat after polishing by the amount of the polishing margins.

Conventionally, a double-sided polishing machine has been used for polishing a sliding surface and an anti-sliding surface of a valve seat. However, in the valve seat after polishing, the polishing amount on the sliding surface side and the polishing amount on the anti-sliding surface side are unbalanced, and a desired polishing margin may not be obtained. This is because the sliding surface and the anti-sliding surface are designed differently (in planar shape and concave-convex shape) and there is a large difference in the actual polishing area between the two surfaces of the molded body, and therefore the polishing height of the surface having a large polishing area is smaller than that of the surface having a small polishing area. The polishing height here refers to a height of each surface that is scraped off by polishing.

Conventionally, as described above, the unbalance of the polishing amounts on the sliding surface side and the anti-sliding surface side is corrected by repairing the molding die. That is, when the sliding surface side and the anti-sliding surface side are polished simultaneously by the double-sided polishing machine, if the polishing remaining amount on one surface is polished and the polishing remaining amount on the other surface remains, the remaining polishing remaining amount on the other surface is hollowed into the mold cavity forming one surface. In general, from the viewpoint of production efficiency, a molding die is formed with a plurality of cavities so that a plurality of products can be obtained. Therefore, the time and cost required for repairing the molding die may be enormous, resulting in an increase in the product cost. In addition, it is considered that in the repair of the primary molding die, the unbalance in the polishing amounts on the sliding surface side and the anti-sliding surface side cannot be corrected, and in this case, the second and third repairs are required, and in this case, the completion of the molding die is delayed, a predetermined production start timing is delayed, and the like.

Further, when polishing is performed on the sliding surfaces of the synthetic resin valve seat and the valve body, polishing burrs are generated so as to reduce the opening areas of the grooves and holes formed in the valve seat and the valve body. The resulting polishing burr may cause a decrease in flow rate, and may peel off during use and bite into the sliding surface. Therefore, the grinding burr needs to be removed. For example, patent document 3 discloses that a recessed portion is provided in an opening portion of an orifice so that the opening of the orifice is not narrowed or blocked by grinding burrs.

However, although providing a recessed portion in the opening of the orifice as in patent document 3 can cope with preventing a flow rate from decreasing, the occurrence of the polishing burr itself cannot be eliminated, and thus the possibility of peeling of the polishing burr during use cannot be eliminated. In the case where the grinding burr bites into the sliding surfaces of the valve seat and the valve body, the sliding surfaces may be damaged and the liquid may leak. In addition, in the human body local cleaning device, there is a concern that the peeled polishing burr blocks the front end hole of the cleaning nozzle, and the function is reduced, which affects the human body.

In this way, when the synthetic resin disk valve is polished, polishing burrs are generated in the opening portions of the groove portion and the hole portion. Therefore, in order to avoid the problem caused by the grinding burr, shot blasting, drum rolling, deburring by manual work, and the like are required, which causes an increase in cost. For example, the polishing Mao Cineng of the outer peripheral portion of the sliding surface is removed by rolling with a roller, but the polishing burrs of the hole portion cannot be removed by a discontinuous brush.

The invention provides a valve seat of a disk valve device and a disk valve device capable of reducing reject ratio and cost in appearance inspection. Further, an object of the present invention is to provide a method for manufacturing a valve seat, which is excellent in sealability and productivity without unbalance in the polishing amounts of both surfaces when polishing the sliding surface side and the fixed surface side (anti-sliding surface side) of the valve seat. Further, an object of the present invention is to provide a synthetic resin disk valve that does not generate polishing burrs even in the disk valve of the disk valve device.

Means for solving the problems

The valve seat of the disk valve device according to the present invention is characterized in that the valve seat is made of synthetic resin, one surface of the valve seat is a sliding surface sliding with the valve body, an anti-sliding surface serving as the other surface is in contact with the housing via a gasket, at least a surface contacting the gasket is a polished surface, and surfaces other than the polished surface are recessed surfaces with respect to the polished surface.

Further, the anti-slip surface may have a surface around the water passage hole as a polishing surface, in addition to a surface in contact with the pad. Here, the periphery of the water passage hole means a region having a width of a predetermined range from the inner edge of the water passage hole, specifically, a region having a width of at least 0.5mm or less from the inner edge of the water passage hole, which surrounds the water passage hole when the sliding prevention surface is viewed from above.

The concave surface is a surface which is lower by 0.05mm to 1.0mm in a direction perpendicular to the polishing surface.

The surface connecting the concave surface and the polishing surface is an inclined surface inclined by 20 DEG to 45 DEG with respect to the polishing surface.

The valve seat is a molded body of a resin composition comprising a polyphenylene sulfide (PPS) resin or a polyether ether ketone (PEEK) resin as a base resin.

Wherein the resin composition further comprises Polytetrafluoroethylene (PTFE) resin. The resin composition further comprises a spherical filler.

Wherein the resin composition does not contain a fibrous filler.

The method for manufacturing a valve seat of the present invention is a method for manufacturing a synthetic resin valve seat of a disk valve device in which a valve body is slid with respect to a valve seat to switch a flow path and a flow rate of a fluid, one surface of the valve seat is a sliding surface sliding with the valve body, and the other surface is a fixed surface (anti-sliding surface) fixed to a housing via a gasket, and is characterized by comprising a polishing step of polishing both surfaces of an object to be polished to form the sliding surface and the fixed surface, and a difference between a polishing area on a sliding surface side and a polishing area on a fixed surface side of the object to be polished is within-20% to 20% of a polishing area on the sliding surface side.

Here, the "polishing area on the sliding surface side of the polishing object" refers to the area of the surface actually polished on the sliding surface side of the polishing object, and the "polishing area on the fixed surface side of the polishing object" refers to the area of the surface actually polished on the fixed surface side of the polishing object. The difference D between the polishing areas can be represented by the following formula (1).

Difference D (%) = ((polishing area on fixed surface side-polishing on sliding surface side) area)/(polishing of sliding surface side area)) x 100. Cndot. 1

The polishing in the polishing step is performed simultaneously on both surfaces of the object to be polished. Further, the polishing is performed by a double-sided grinder.

The method for manufacturing the polishing device is characterized by comprising a molding step of injection molding a resin composition to obtain a molded body to be the object to be polished, wherein the molding step is performed such that the polishing area on the fixed surface side is larger than the polishing area on the sliding surface side.

The molding has a recess formed in a surface of the molding on the fixed surface side, the recess being formed deeper than a polishing margin of the surface.

The disk valve device of the present invention is characterized in that the valve seat is the valve seat of the present invention, and the disk valve device includes a valve seat, a valve body, and a packing in contact with the valve seat.

The disk valve according to the present invention is a synthetic resin disk valve used in a disk valve device for switching a flow path and a flow rate of a fluid and sliding with a disk valve on the opposite side, wherein a sliding surface of the disk valve is a polished surface formed with a recess, the recess is at least one of a groove portion and a hole portion into which the fluid is introduced, and the disk valve has an inclined portion inclined by 10 ° to 25 ° with respect to the polished surface around an opening portion of the recess of the polished surface.

Wherein the width of the inclined portion of the polishing surface is in the range of 5 μm to 500 μm.

ADVANTAGEOUS EFFECTS OF INVENTION

The valve seat of the disk valve device of the present invention is made of synthetic resin, one surface of the valve seat is a sliding surface with the valve body, the other surface is an anti-sliding surface having a surface contacting with the gasket, at least the surface contacting with the gasket is a polished surface, and the surface except the polished surface in the anti-sliding surface is a concave surface recessed relative to the polished surface, so that in the case of damage such as a bump on the anti-sliding surface, whether the surface is a part which has no influence on the function can be easily judged. In this way, in the appearance inspection, it is not necessary to eliminate damage to a portion that does not affect the function as a defective product, and the defective rate can be reduced.

In addition, by taking the surface around the water passage hole as a polishing surface, the distance between the water passage hole of the valve seat and the water passage hole of the housing is made closer, except for the surface in contact with the pad, of the anti-slip surface. Accordingly, excessive water pressure is easily prevented from acting on the gasket, and water is easily prevented from leaking out of the gasket.

Since the concave surface is a surface 0.05mm to 1.0mm lower in the direction perpendicular to the polishing surface, it is easier to distinguish whether or not it is a flaw in a portion that does not affect the function, and the time required for the appearance inspection can be shortened.

Since the surface connecting the concave surface and the polishing surface is an inclined surface inclined by 20 ° to 45 ° with respect to the polishing surface, generation of polishing burrs during polishing can be suppressed, and even if polishing burrs are generated, the polishing burrs can be easily removed. This reduces the burden of the polishing burr removal process, and is less likely to cause damage to the valve seat, thereby reducing the reject ratio. In addition, the defect caused by peeling of the grinding burr from the portion in use is eliminated. That is, damage to the sliding surface due to biting of the grinding burr into the sliding surface of the valve seat and the valve body can be prevented, and water leakage can be prevented. In addition, the rubber gasket is not damaged by the grinding burr, and the sealing effect of the gasket can be maintained. In addition, for example, when the polishing device is used in a human body local cleaning device, it is possible to prevent the peeled polishing burr from clogging the tip hole of the cleaning nozzle and degrading the function, and further to eliminate the influence on the human body.

The valve seat is a molded article of a resin composition comprising a PPS resin or a PEEK resin as a base resin, and therefore has excellent sliding properties, low water absorption, excellent water resistance, and easy polishing.

Since the resin composition further contains a PTFE resin, the sliding characteristics can be further improved by polishing or the like. Further, since the resin composition further contains a spherical filler, anisotropy of orientation does not occur, and torque variation in the sliding direction is avoided. In addition, even if the spherical filler exposed to the sliding surface is detached, the running water is held in the concave portion of the detachment mark, so that the lubrication effect in water can be promoted, and the sliding property is more excellent.

The resin composition does not contain a fibrous filler, and therefore can equalize the surface roughness of the polished surface and stabilize the quality.

The method for manufacturing a valve seat according to the present invention includes a polishing step of polishing both surfaces of a polishing object to form a sliding surface and a fixed surface (anti-sliding surface) of the valve seat, wherein a difference between a polishing area on the sliding surface side and a polishing area on the fixed surface side of the polishing object is within-20% to 20% of the polishing area on the sliding surface side, and therefore, a difference between respective polishing speeds (a thickness which can be polished for a certain period of time) of the sliding surface side and the fixed surface side of the polishing object is within a predetermined range, and the polishing amounts of both surfaces are not unbalanced, and uniform polishing amounts can be achieved. As a result, the sealing performance between the valve body and the housing via the fixing portion of the gasket and the contact portion with the valve body is excellent. In addition, it is not necessary to repair the molding die with unbalance of the polishing amount, and the time and cost for repairing the die can be reduced, thereby improving productivity.

The polishing in the polishing step is performed simultaneously on both surfaces of the object to be polished, and for example, a double-sided grinder is used, so that the time required for polishing the valve seat can be shortened, and the productivity is improved.

In the valve seat, the shape of the sliding surface and the fixed surface tends to be large in the concave area of one of the sliding surfaces for switching the flow path of the valve body. In this way, in the object to be polished (molded body), the polishing area tends to be greatly increased as compared with the surface on the sliding surface side. Even in this case, since the molded body obtained in the molding step has the concave portion formed deeper than the polishing margin of the fixed surface side, the polishing area can be reduced by the concave portion, and the difference between the polishing areas can be easily made within a predetermined range.

The disk valve device of the present invention includes the valve seat, the valve body, and the packing in contact with the valve seat of the present invention in the housing, and as a result, cost reduction of the disk valve device can be expected.

The disk valve of the present invention is a synthetic resin disk valve, wherein the sliding surface is a polished surface formed with a recess, the recess is at least one of a groove portion and a hole portion for introducing a fluid, and an inclined portion inclined by 10 ° to 25 ° with respect to the polished surface is provided around an opening portion of the recess of the polished surface, so that generation of polishing burrs on the sliding surface can be suppressed. Therefore, the defect caused by peeling of the grinding burr in use is eliminated. That is, damage to the sliding surface caused by biting of the polishing burr into the sliding surfaces of the disc valve and the counter disc valve can be prevented, and leakage of liquid can be prevented. In addition, for example, when the polishing device is used in a human body local cleaning device, it is possible to prevent the peeled polishing burr from clogging the tip hole of the cleaning nozzle and degrading the function, and further to eliminate the influence on the human body.

Since the width of the inclined portion of the polishing surface is in the range of 5 μm to 500 μm, unnecessary interference with the opposite side disk valve can be prevented, and as a result, leakage of liquid can be prevented.

Drawings

Fig. 1 is a plan view of an example of a valve body of a disc valve device as viewed from the sliding surface side.

Fig. 2 is a plan view of an example of a valve seat of the disc valve device as seen from the sliding surface side.

Fig. 3 is a plan view of the valve seat of fig. 2 as seen from the side of the anti-slip surface.

Fig. 4 is an enlarged cross-sectional view of portions a and B of fig. 3.

Fig. 5 is an enlarged cross-sectional view for explaining the concave portion of the molded body.

Fig. 6 is a perspective view of another example of the valve body of the disc valve device as viewed from the sliding surface side.

Fig. 7 is a perspective view of another example of the valve seat of the disc valve device as seen from the sliding surface side.

Fig. 8 is an enlarged cross-sectional view of an inclined portion of a concave portion formed in a sliding surface.

Fig. 9 is a perspective view of the valve seat of test example A1.

Fig. 10 is a perspective view of the valve seat of test example A2.

Fig. 11 is a plan view of the disk-shaped molded body of test example C.

Fig. 12 is a cross-sectional view of a through hole formed in the disc-shaped molded body.

Fig. 13 is a side view of a body part cleaning device.

Fig. 14 is a schematic cross-sectional view of a body part cleaning device.

Detailed Description

As an example of the disc valve device of the present invention, a human body local cleaning device will be described with reference to fig. 13. The body part washing device 51 includes a housing 52, and a drive device 53, wherein the housing 52 includes a disk valve unit 60 as a flow path switching mechanism therein, and the drive device 53 drives the flow path switching mechanism in the housing 52. The flow path switching mechanism provided in the housing 52 is composed of a valve body 61 and a valve seat 62. The housing 52 is connected to a washing water supply device 54 for supplying washing water into the housing 52, a human body local washing nozzle 55 for ejecting the washing water supplied from the washing water supply device 54 to a human body local part, a nozzle washing water discharge portion 56 for washing the human body local washing nozzle 55, and a water discharge portion 57 for discharging the washing water.

The body part cleaning device 51 has the following structure: by driving the flow path switching mechanism inside the casing 52 by the driving device 53, the flow path inside the casing 52 is switched, and the cleaning water from the cleaning water supply device 54 is caused to flow to either the human body local cleaning nozzle 55 or the nozzle cleaning water discharge portion 56.

As shown in fig. 13, in the disc valve unit 60, a valve seat 62 (fixed disc) is fixed so as not to be rotatable with respect to the housing 52, a valve body 61 (movable disc) is rotatable with respect to the valve seat 62, and the valve body 61 and the valve seat 62 are arranged so that respective sliding surfaces are slidable with respect to each other. The valve body 61 is rotatable while sliding around the center of its circular shape as a rotation axis, and the valve body 61 and the hole and groove of the valve seat 62 overlap or are offset from each other, thereby changing the flow path and flow rate of water. The disk valve of the present invention may be a valve body of a disk valve device or a valve seat.

The internal structure of the body part washing apparatus will be described with reference to fig. 14. Fig. 14 is a schematic cross-sectional view taken along the rotation axis direction of the driving device. As shown in fig. 14, the housing 52 accommodates: a valve body 61 rotated by the driving device 53; a valve seat 62 fixed to the housing 52 so as not to rotate and having a water passage hole communicating with the human body partial cleaning nozzle and the nozzle cleaning water discharge portion; and a gasket 58 having a structure corresponding to the shape and position of the water passage hole. The gasket 58 connects the valve seat 62 and the flow path of the housing 52, and allows the cleaning water to flow to the human body partial cleaning nozzle, the nozzle cleaning water discharge portion, and the water discharge portion. As described above, the valve seat 62 is arranged in such a manner that one face thereof is arranged opposite to the valve body 61, and the other face thereof is opposite to the packing 58. The anti-slip surface 62a of the valve seat 62 opposite the gasket 58 contacts the housing 52 via the gasket 58.

As an example of the disc valve provided in the disc valve device of the present invention, fig. 1 shows a valve body, and fig. 2 shows a valve seat. Fig. 1 is a plan view of the valve body, showing a sliding surface side sliding with the valve seat. The sliding surface 1a is a polished surface smoothly polished by a mechanical method such as a double-sided grinder. As shown in fig. 1, a recess 1b including grooves and holes of various shapes is formed in the sliding surface 1a of the valve body 1. The concave portion 1b constitutes a flow path (water passage) of tap water.

Next, fig. 2 is a plan view of the valve seat, showing a sliding surface side sliding with the valve body. The sliding surface 3 of the valve seat 2 and a part of the anti-sliding surface on the back side of the sliding surface 3 are polished surfaces that are smoothly polished by a mechanical method such as a double-sided grinder. As shown in fig. 2, grooves 4 and water holes 5 of various shapes that constitute a water passage are formed in the sliding surface 3 of the valve seat 2. In fig. 2, the water passage 5 is a through hole penetrating from the sliding surface 3 to the anti-sliding surface.

The structure of the sliding surface side of the valve body and the valve seat, which is treated with the polishing burr, will be described later.

Fig. 3 is a plan view of the anti-slip surface side of the valve seat shown in fig. 2. The respective water passage holes 5 on the side of the sliding prevention surface are divided by a packing that contacts the valve seat 2. By contact with the gasket, water is prevented from leaking from the housing when the disc valve device is in use. In fig. 3, the anti-slip surface 6 is composed of a surface (contact surface) 7 that contacts the pad, a surface (peripheral surface) 8 around the water passage hole 5, and a concave surface 9. The contact surface 7 and the peripheral surface 8 are abrasive surfaces. The concave surface 9 is formed by recessing a surface other than the polishing surface (non-polishing surface) by a predetermined depth with respect to the polishing surface. The polishing surface is also referred to herein as a convex surface, and in fig. 3, the convex surface is a surface where the contact surface 7 and the peripheral surface 8 are combined.

As shown in fig. 3, the peripheral surface 8 of the water passage hole 5 is not necessarily a polished surface (convex surface), and may be a surface recessed from the contact surface 7. In this case, the peripheral surface 8 is formed by a surface continuous with the concave surface 9. However, since the water flow is difficult to deviate from the water passage by making the peripheral surface 8 a polishing surface and the water passage holes 5 close to the case, excessive water pressure is not applied to the pad, and water leakage from the pad is easily prevented.

Here, since the valve seat 2 is made of synthetic resin, the surface may be damaged in the manufacturing process. For example, in a cleaning step of a drum process after polishing with a double-sided grinder, a polishing burr removing step of a sand blast process, or the like, a dent as a bump may be left on a polished surface. In particular, if a dent is left on the sealing surface (the contact surface 7 with the gasket) of the anti-slip surface, the sealability is lowered, and water leakage may occur. In contrast, in the example of fig. 3, the surface of the sliding prevention surface 6 of the valve seat 2 other than the polishing surface (including at least the contact surface 7) is formed as the concave surface 9 recessed from the polishing surface, and therefore, the valve seat whose polishing surface is not damaged but damaged other than the polishing surface can be used as a conforming product. As a result, the reject ratio of the valve seat is reduced, and the production efficiency is improved.

In fig. 3, the depth of the concave surface 9 in the direction perpendicular to the polishing surface is not particularly limited, but the concave surface 9 is preferably a surface 0.05mm to 1.0mm lower than the polishing surface. In the case where the difference in height is less than 0.05mm, management in the polishing process may become complicated, and in the case where the difference in height is greater than 1.0mm, the thickness between the concave surface 9 and the groove portion of the sliding surface may become thin. As shown in fig. 3, a plurality of concave surfaces 9 are formed on the anti-slip surface 6. The depth of the concave surface 9 with respect to the polishing surface may be set to a constant depth for all the concave surfaces or may be set to be different for each concave surface. The depth may be set to vary depending on the position of each concave surface. Further, the concave surface 9 is more preferably a surface 0.1mm to 0.5mm lower than the polished surface.

The valve seat 2 is an injection molded article of a resin composition, and the concave surface 9 is an injection molded surface. That is, the anti-slip surface 6 of the valve seat 2 is formed by injection molding, and then the convex surface (the contact surface 7 and the peripheral surface 8) is finished by grinding. Thus, the convex surface is formed by setting a grinding allowance by injection molding. The grinding allowance is about 0.05 mm-0.3 mm. Therefore, it is preferable that the difference in height between the convex surface and the concave surface of the sliding prevention surface before polishing after injection molding is 0.1mm to 1.3mm. If the polishing margin is less than 0.05mm, there is a possibility that black skin remains on the polished surface due to shrinkage, and if the polishing margin is greater than 0.3mm, the polishing time becomes longer, and the production efficiency may be lowered.

The relationship between the convex surface and the concave surface of the sliding prevention surface will be described with reference to fig. 4. Fig. 4 shows a cross-sectional view of a portion a and a portion B surrounded by a broken line in fig. 3, respectively. Fig. 4 (a) is an enlarged cross-sectional view of the boundary portion between the concave surface 9 and the contact surface 7. As shown in fig. 4 (a), it is preferable to provide a slope on the wall surface which is the boundary between the concave surface 9 and the contact surface 7. In fig. 4 (a), the inclined surface 10 connecting the concave surface 9 and the contact surface 7 is inclined at 40 ° with respect to the contact surface 7. The inclined surface 10 is preferably inclined at 20 ° to 45 ° with respect to the contact surface 7. This makes it easy to suppress the occurrence of polishing burrs, and to remove polishing burrs even when polishing burrs are generated. More preferably, the inclination angle of the inclined surface 10 is 25 ° to 40 °.

In addition, in the enlarged cross-sectional view of fig. 4 (b), the boundary between the concave surface 9 and the surrounding surface 8 is also shown. As shown in fig. 4 (b), a slope is preferably provided on the wall surface which is the boundary between the concave surface 9 and the peripheral surface 8. In fig. 4 (b), the inclined surface 11 connecting the concave surface 9 and the peripheral surface 8 is inclined at 40 ° with respect to the peripheral surface 8. The inclined surface 11 is preferably inclined at 20 ° to 45 °, more preferably 25 ° to 40 °, with respect to the peripheral surface 8.

As shown in fig. 4, by providing an inclined surface connecting the concave surface 9 and the convex surface (the contact surface 7 and the peripheral surface 8) at the boundary between the concave surface 9 and the convex surface, the occurrence of polishing burrs is more easily suppressed than in the case of providing an upright wall surface. The inclined surface may be provided at one of the boundary between the concave surface 9 and the contact surface 7 and the boundary between the concave surface 9 and the surrounding surface 8, but is preferably provided at the boundary between both sides. In this case, the surfaces connecting the concave surface 9 and the convex surface are all formed as inclined surfaces. In addition, in the case where the inclined surface is formed at the boundary, the inclined surface may be formed only around the convex surface, but since the polishing residue is likely to remain at the corner of the concave surface 9, the time for the cleaning process is likely to be long, and therefore, it is preferable that the inclined surface is formed so as to connect the concave surface 9 and the convex surface. The inclination angles of the inclined surfaces may be the same as each other or may be different from each other.

An example of a method for manufacturing a valve seat according to the present invention will be described below. The production method of the present invention is not limited to the method described below.

The manufacturing method of the present invention comprises: a molding step of injection molding the resin composition to obtain a molded body (polishing object); and a polishing step of polishing both surfaces of the molded body to form a sliding surface 3 (see fig. 2) and an anti-sliding surface (fixed surface) 6 (see fig. 3). In the present invention, the difference between the polishing area on the sliding surface side and the polishing area on the fixed surface side of the polishing object before polishing is within-20% to 20% of the polishing area on the sliding surface side. That is, the polishing area actually polished on the sliding surface side of the object to be polished is substantially equal to the polishing area actually polished on the fixed surface side. This can prevent uneven polishing amount caused by polishing. The difference in polishing area is preferably within a range of-15% to 15%, more preferably within a range of-10% to 10%. The difference is calculated by the above formula (1).

In the present invention, the size relationship between the polishing area on the sliding surface side and the polishing area on the fixed surface side is not particularly limited.

In the molding step, molding pellets obtained by melt-kneading a resin composition described later are used and molded into a predetermined shape by a known injection molding method. For example, in consideration of the flow path design of the disk valve, the polishing rate in the polishing step, and the like, the sliding surface and the fixed surface are provided with irregularities, respectively. The molded article obtained in the molding step serves as an object to be polished in the subsequent polishing step. Therefore, in the molding step, the molded article is molded so that the difference between the polishing areas is within-20% to 20%. For example, as shown in fig. 3, the difference in polishing area is adjusted by molding a molded body having a concave surface recessed from the polishing surface on the fixed surface side (anti-slip surface side).

In general, in the valve seat, the sliding surface for switching the flow path with the valve body is more complicated in terms of the shapes of the sliding surface and the fixed surface. As a result, one of the sliding surfaces formed into the concave area tends to be large. Therefore, in the object to be polished, the polishing area actually to be polished tends to be larger on the fixed surface side than on the sliding surface side, and the difference between the polishing areas tends to be large.

In response to this, it is preferable to form a concave portion in the surface of the molded body on the fixed surface side, and to reduce the polishing area on the fixed surface side. The recess may also be referred to as an adjustment recess for adjusting the polishing area. By forming the concave portion, the polishing area on the fixed surface side is easily made substantially equal to the polishing area on the sliding surface side. Fig. 5 shows an enlarged cross-sectional view of the recess of the molded body. Fig. 5 shows a state before polishing of the valve seat shown in fig. 4 (a).

As shown in fig. 5, a concave portion 13 is formed in a surface 12a of the molded body 12 on the fixed surface side. Depth D of the recess 13 _a Grinding allowance D formed to be larger than surface 12a on fixed surface side _b Deep. Depth D _a Is from the surface 12a on the fixed surface side to the concave surface 13a as the surface that is not polished. For example, the polishing margin D on the fixed surface side _b In the case of 0.2mm, the depth D _a Is formed larger than 0.2mm, for example, 0.3mm. Depth D _a Is formed to be larger than the grinding allowance D _b For example, 0.03mm to 0.5mm.

In fig. 5, the polishing margin D is removed from the molded body 12 _b The surface of the number of (a) is a contact surface 7 (see fig. 4 (a)). The concave surface 13a of the concave portion 13 is the concave surface 9 of the valve seat (see fig. 4 (a)).

The recess 13 of the molded body 12 can be formed by changing the shape of the cavity of the injection molding die. The recess 13 is formed by a convex portion of the cavity. In order to prevent burrs from being generated by polishing, it is preferable to provide a slope on the wall surface 13b that is a boundary between the concave portion 13 and the surface 12a on the fixed surface side. The inclination is preferably 20 ° to 45 °, more preferably 25 ° to 40 °, with respect to the surface 12a on the fixed surface side, which is the surface to be polished.

The position of forming the recess on the surface of the molded body on the fixed surface side is not particularly limited, but is preferably formed on the valve seat other than the surface 7 (see fig. 3) in contact with the gasket and the surface 8 (see fig. 3) around the water passage hole 5. In general, the fixing surface is a flat surface except for the concave portion of the water passage, but there is no functional problem in that the fixing surface is concave except for the portion in contact with the pad, and thus the concave portion may be formed at this portion. In other words, since the portion in contact with the pad cannot be recessed, the polishing area is adjusted in relation to the contact area of the pad. Therefore, it may be difficult to make the difference between the polishing areas zero.

In the polishing step, both surfaces of the molded body are polished simultaneously, for example, using a double-sided grinder. The polishing residue on each surface was removed by this polishing.

After the polishing step, if necessary, shot blasting, barreling, or the like may be performed, or the polishing burr may be removed and the projection material may be cleaned.

Next, the structure of the sliding surface side of the valve body and the valve seat will be described. As another example of the disk valve included in the disk valve device of the present invention, fig. 6 shows a valve body, and fig. 7 shows a valve seat. Fig. 6 shows a sliding surface side sliding with the valve seat, and fig. 7 shows a sliding surface side sliding with the valve body. In the following description, a valve seat is used as a disk valve, but the same applies to a valve body. In fig. 7, the sliding surface 23 of the valve seat 22 is a smooth polished surface polished by a mechanical method such as a double-sided grinder.

As shown in fig. 7, a recess 24 is formed in a sliding surface (polishing surface) 23 of the valve seat 22, and the recess 24 is formed of various grooves and holes that form a fluid flow path. The groove portion is a recess portion which does not penetrate to the anti-slip surface side, and the hole portion is a recess portion which penetrates to the anti-slip surface side. In fig. 7, a predetermined inclination angle is provided around the opening 25 of the recess 24. Here, the opening periphery 25 is a region at the boundary between the sliding surface 23 and the inner edge of the concave portion 24, and is a region having a width within 1mm of the edge of the concave portion 24 when the sliding surface 23 is viewed in plan.

Fig. 8 shows an enlarged view of a cross section of the valve seat 22 in the thickness direction around an opening (not shown) of the recess 24 of the valve seat 22. The angle θ of the inclined portion 26 around the opening portion is an angle of an inner angle of the inclined portion 26 with respect to the sliding surface (polishing surface) 23.

The angle θ is preferably 10 ° to 25 °, more preferably 15 ° to 25 °. If the angle θ is less than 10 °, it becomes difficult to manage the tilt left after grinding, and if it is more than 25 °, it may be difficult to obtain an effect of preventing generation of grinding burrs. In addition, the control of the inclined portion left after polishing is difficult because the dimensional change of the width w of the inclined portion left on the polishing surface by polishing is large, and therefore high accuracy is required for the control of the polishing amount. The angle θ is preferably 10 ° to 25 °, and may be fixed over the entire circumference of the recess 24 or may be set differently depending on the location. In addition, the concave portions may be set to be different from one concave portion to another.

The width w of the sliding surface 23 of the inclined portion is in the range of 5 μm to 500. Mu.m, preferably in the range of 5 μm to 300. Mu.m, and more preferably in the range of 5 μm to 100. Mu.m. The width w is a length in the horizontal direction of the inclined portion 26, which is divided into the depth direction and the horizontal direction when the inclined portion 26 is viewed from a cross section in the thickness direction of the valve seat 22, and is a length in the radial direction which is radial from the inner edge of the recess 24 when the sliding surface 23 is viewed from above. If the width w is less than 5 μm, it becomes difficult to visually confirm whether or not the inclination is present, and it takes time to perform the polishing step. On the other hand, if the width w is larger than 500 μm, there is a possibility that the leakage may occur. The width w may be constant over the entire circumference of the recess 24, or may be set differently depending on the location. In addition, the concave portions may be set to be different from one concave portion to another.

The structure of the sliding surface of the valve body and the valve seat shown in fig. 6 and 7 can also be applied to the valve body and the valve seat shown in fig. 1 and 2.

The disk valve of the present invention is an injection molded article of a resin composition comprising a base resin having sliding properties. As the base resin, for example, polyacetal resin, polyimide resin, polyamide resin, fluororesin, PPS resin, PEEK resin, or the like can be used. Particularly, PPS resins and PEEK resins are preferable because they have a low water absorption, excellent water resistance, and easy polishing. The resin composition may be composed of only a base resin (100% of the base resin), and a filler such as a solid lubricant or a spherical filler described below may be appropriately blended into the base resin.

As the filler, for example, a solid lubricant such as graphite, molybdenum disulfide, or PTFE resin is preferably blended in order to improve the lubricating property. Among them, PTFE resins are preferable because of their high lubricity imparting effect. The blending amount of the solid lubricant is 5 to 60 parts by mass, preferably 10 to 45 parts by mass, and more preferably 20 to 30 parts by mass, relative to 100 parts by mass of the base resin. If the amount is less than 5 parts by mass, the effect of improving the lubricity is hardly obtained, and if it exceeds 60 parts by mass, the damage to the polishing surface tends to be increased, the reject ratio tends to be high, and even if the polishing surface is inclined, the occurrence of polishing burrs tends to be difficult to be prevented.

Further, the filler is composed of a spherical filler such as spherical graphite or glass beads, whereby the sliding characteristics are stabilized and easily obtained. The reason for this is that since anisotropy does not occur in the mating direction, the slip torque does not change depending on the slip direction. In addition, even if the spherical filler is cut into a hemispherical shape by grinding and the hemispherical filler exposed on the sliding surface falls off by a subsequent process such as rolling by a roller, tap water is held in the concave portion of the falling trace during use, and the lubrication effect in water is improved. The amount of the spherical filler to be blended is 5 to 30 parts by mass, preferably 5 to 20 parts by mass, based on 100 parts by mass of the base resin. If it is less than 5 parts by mass, it is difficult to obtain a reinforcing effect, and if it exceeds 30 parts by mass, the low friction may be lowered.

As the spherical filler, glass beads are preferably used. The average particle diameter of the glass beads is not particularly limited, but is preferably 5 μm to 100. Mu.m, more preferably 5 μm to 50. Mu.m. The average particle diameter of the glass beads is, for example, a number average particle diameter calculated from the measured particle diameter by extracting and measuring glass beads as objects of the particle diameter from an image obtained by observation with an electron microscope.

The resin composition preferably does not contain a fibrous filler such as glass fiber or carbon fiber. If fibrous fillers are contained, the surface roughness after grinding may become uneven.

In view of these, as the resin composition for forming the disk valve, a resin composition containing 20 to 30 parts by mass of a PTFE resin and 5 to 20 parts by mass of glass beads per 100 parts by mass of a base resin of PPS resin or PEEK resin and containing no fibrous filler is particularly preferable. The average particle diameter of the glass beads is preferably 5 μm to 50. Mu.m.

In one embodiment of the disk valve device of the present invention, there is provided a synthetic resin disk valve unit for switching a flow path and a flow rate of a fluid, the disk valve unit comprising a spool and a valve seat which slide with each other, each sliding surface of the spool and the valve seat being a polished surface formed with a recess, the recess being at least one of a groove portion and a hole portion into which the fluid is introduced, the spool and the valve seat having an inclined portion inclined by 10 ° to 25 ° with respect to the polished surface around an opening portion of the recess of each polished surface. In this case, the valve element and the valve seat can each appropriately adopt the above-described structure.

In the disk valve device of the present invention, when the valve body is made of a synthetic resin, the respective resin compositions used for the valve body and the valve seat may be the same resin composition or may be different from each other. From the viewpoint of simplifying the manufacturing process, the respective resin compositions for the valve body and the valve seat are preferably the same resin composition. The resin compositions different from each other are different in composition, and include not only the case where the respective materials constituting the valve body and the valve seat are different, but also the case where the respective materials are the same and the composition ratio is different. For example, the base resin of the valve seat may be PPS resin, and the base resin of the valve body may be PEEK resin.

Examples

Test example A

In order to verify the effect of providing a concave surface on the surface other than the polished surface of the valve seat, the valve seat was manufactured and inspected in the following order.

(1) A valve seat having a concave surface on the anti-slip surface (test example A1: see FIG. 9) and a valve seat having no concave surface on the anti-slip surface (test example A2: see FIG. 10) were injection molded using the same resin composition. The resin composition used was a resin composition containing 25 parts by mass of a PTFE resin and 15 parts by mass of glass beads per 100 parts by mass of a PPS resin. The sliding surfaces of the valve seats were the same shape in test example A1 and test example A2.

(2) The sliding surface and the anti-sliding surface are ground by a double-sided grinder, and the thickness dimension of the valve seat is finished. The grinding allowance is 0.2mm on the sliding surface side and the anti-sliding surface side. In the valve seat 31 of test example A1 in fig. 9, the concave surface 31d is a surface lower by 0.2mm in the direction perpendicular to the polished surface (the contact surface 31b and the peripheral surface 31 c). The surface connecting the concave surface 31d and the polishing surface is an inclined surface of 40 °.

(3) Then, shot blasting and barreling are performed on each valve seat, and removal of the grinding burr and cleaning of the projection material are performed.

(4) The valve seat with the damaged polished surface was removed as a defective product by performing an appearance inspection on each valve seat obtained by a person. The ratio of defective parts to all valve seats produced was calculated as the defective ratio, and the defective ratios of each of test example A1 and test example A2 were compared. As a result, the reject ratio of test example A1 was about 3/5 of that of test example A2. In the valve seat of test example A1, the number of products that can be used as acceptable products at the time of appearance inspection increases, so that the reject ratio can be reduced. In addition, no polishing burr remained on the edge of the sliding surface of test example A1.

Test example B

The influence of the difference in polishing area between the surfaces actually polished on the two surfaces of the object to be polished was confirmed.

(1) The same resin composition was used to mold a molded article having a concave portion on the surface on the fixing surface side (test examples B1 and B2) and a molded article having no concave portion on the surface on the fixing surface side (test example B3) by injection molding. The resin composition used was a resin composition containing 25 parts by mass of a PTFE resin and 15 parts by mass of glass beads per 100 parts by mass of a PPS resin. In test example B1, a recess shown in fig. 9 was formed on the surface on the fixed surface side by additional processing so that the difference between the polishing area on the sliding surface side and the polishing area on the fixed surface side was 20% (the polishing area on the fixed surface side was 20% larger than the polishing area on the sliding surface side). In test example B2, the recess shown in fig. 9 was formed on the surface on the fixed surface side by additional processing so that the difference between the polishing area on the sliding surface side and the polishing area on the fixed surface side was 10% (the polishing area on the fixed surface side was 10% greater than the polishing area on the sliding surface side). In test example B3, the molded state was maintained without additional processing of the fixing surface. The difference between the polishing area on the sliding surface side and the polishing area on the fixed surface side was 70% (the polishing area on the fixed surface side was 70% larger than the polishing area on the sliding surface side).

The polishing margins of the molded bodies of test examples B1 to B3 were 0.2mm each. The depth of the recess formed in the fixed surface side of the molded bodies of test example B1 and test example B2 was 0.4mm. Further, on the surface of the molded bodies of test example B1 and test example B2 on the fixed surface side, an inclination of 40 ° was formed with respect to the planar portion on the wall surface at the boundary between the polished surface (planar portion) and the concave portion. The sliding surfaces of the valve seats were the same shape in test examples B1 to B3.

(2) The sliding surface side surface and the fixed surface side surface of the obtained molded body were polished by a double-sided grinder, and the thickness dimension was finished.

(3) Then, the polished compact is shot-blasted and barred, and the polishing burr is removed and the projection material is cleaned.

(4) The polishing amounts on the sliding surface side and the fixed surface side were measured for the valve seat manufactured through the steps (1) to (3) above. The results are shown in Table 1.

TABLE 1

As shown in Table 1, the difference between the polishing amounts on the sliding surface side and the fixed surface side in test example B1 and test example B2 was 0.024mm and 0.010mm, respectively, and the polishing amounts were the levels having no influence on the water discharge amount. On the other hand, the difference between the polishing amounts on the sliding surface side and the fixed surface side in test example B3 was 0.130mm, which is a level that affects the water discharge amount. Therefore, it is considered that the mold needs to be repaired in the case of test example B3.

Test example C

In order to examine the relationship between the inclination angle of the periphery of the opening portion of the concave portion with respect to the sliding surface of the disk valve and the occurrence of polishing burrs, the following test was performed using a disk-shaped molded body simulating the disk valve.

An injection molded article (diameter. Phi. 20mm, thickness 4 mm) was obtained by injection molding using a resin composition containing 25 parts by weight of a PTFE resin and 15 parts by weight of glass beads (average particle diameter 20 to 30 μm) per 100 parts by weight of a PPS resin. The both surfaces of the obtained injection molded article were polished by a predetermined amount by a double-sided grinder. After polishing, abrasive grains adhering to the surface of the injection molded article were removed by roller polishing, and a disk-shaped molded article was obtained.

Fig. 11 shows top views of the front and back surfaces of the obtained disk-shaped molded body. The surfaces on which the inclined portions of test examples C1 to C6 described later are formed are referred to as front surfaces, and the surfaces on which the inclined portions of test examples C7 to C12 are formed are referred to as rear surfaces. Fig. 11 (a) is a front view, and fig. 11 (b) is a rear view.

As shown in fig. 11, through holes (recesses) 34 to 39 having a diameter of 1.5mm are formed in each of the front and rear surfaces of the disc-shaped molded body 33, and a tilt of a predetermined angle shown in table 2 is formed around the openings of the front and rear surfaces of the through holes 34 to 39.

Fig. 12 shows a cross section in the thickness direction of the disc-shaped molded body 33 in which the through hole 38 of the inclined portion of test example C5 is formed, as an example of a cross section of the through hole. The inclined portion of test example C5 is formed on the front side of the through hole 38, and the inclined portion of test example C9 is formed on the rear side. In addition, since the surface before polishing is polished to be horizontal, the angle of inclination before and after polishing is unchanged.

The presence or absence of polishing burrs at each inclined portion of the disc-shaped molded body 33 was confirmed by a microscope (magnification 100). The results are also shown in Table 2.

TABLE 2

The number of disc-shaped molded bodies having polishing burrs was counted among 10 in each test, and the presence or absence of polishing burrs in the inclined portion was evaluated based on the following criteria.

O: full-automatic grinding burr-free machine

Delta: has 1 to 9 grinding burrs

X: all have grinding burrs

As shown in table 2, by forming an inclined portion of 10 ° to 25 ° with respect to the polishing surface around the opening portion of the through hole as the recess portion of the polishing surface, the occurrence of polishing burrs can be prevented.

Next, an injection molded article was molded using a PEEK resin (resin composition made of only PEEK resin) containing no filler and using the same mold as in the above test C. The injection molded article was subjected to the same double-sided polishing as in test C, and the abrasive grains adhering to the surface of the injection molded article were removed by barrel polishing. The obtained disk-shaped molded body was observed with a microscope (magnification: 100 times), and the presence or absence of polishing burrs at each inclined portion was confirmed. As a result, the state of the polishing burr was confirmed to have the same tendency as in table 2.

Industrial applicability

The valve seat of the disc valve device of the present invention can reduce the reject ratio and can be expected to reduce the cost, and therefore can be widely used as a valve seat of a disc valve device such as a warm/cold water mixing faucet or a human body local cleaning device. In the method for manufacturing the valve seat of the disk valve device of the present invention, even if both the sliding surface side surface and the fixed surface side surface of the molded body are simultaneously processed by polishing, the same amount can be polished separately. Therefore, repair of the molding die due to uneven polishing amount is not required, and time and cost for repairing the die can be prevented from being wasted. The disk valve according to the present invention is a synthetic resin disk valve, but since the polishing burr generated when the polishing surface is not generated, the problem caused by peeling of the polishing burr during use can be eliminated, and the disk valve can be widely used as a disk valve for a refrigerant valve device, a human body local cleaning device, or the like.

Description of the reference numerals

1 valve core (disk valve)

2 valve seat (disk valve)

3 sliding surface

4 groove part

5 water holes

6 anti-slip surface (fixed surface)

7 contact surface

8 peripheral surface

9 concave surface

10. Inclined surface

11. Inclined surface

12 shaped body (object to be polished)

13 concave part

21 valve core (disk valve)

22 valve seat (disk valve)

23. Sliding surface

24. Concave part

25. Around the opening

26. Inclined part

31. Valve seat

33. Disc-shaped molded body

34-39 through holes

51 human body local cleaning device (disk valve device)

52. Shell body

53. Driving device

54. Cleaning water supply device

55. Nozzle for cleaning local part of human body

56. Cleaning water discharge part

57. Drainage part

58. Gasket for a vehicle

60. Disk valve unit

61 valve core (disk valve)

62 valve seat (disk valve)

Claims

1. A valve seat of a disk valve device for switching a flow path and a flow rate of a fluid by sliding a valve body relative to the valve seat, characterized in that,

the valve seat is made of synthetic resin, one surface of the valve seat is a sliding surface sliding with the valve core, the sliding preventing surface as the other surface is contacted with the shell through a gasket,

at least a surface of the anti-slip surface in contact with the pad is a polishing surface, and a surface of the anti-slip surface other than the polishing surface is a concave surface recessed from the polishing surface.

2. The valve seat of claim 1, wherein said abrasive surface is a surface in contact with said gasket and a surface around the water passage hole.

3. The valve seat of claim 1, wherein the concave surface is a surface 0.05mm to 1.0mm lower in a direction perpendicular to the polishing surface.

4. The valve seat of claim 1, wherein a surface connecting said concave surface and said polishing surface is an inclined surface inclined from said polishing surface by 20 ° to 45 °.

5. The valve seat of a disc valve apparatus according to claim 1, wherein the valve seat is a molded body of a resin composition having a polyphenylene sulfide resin or a polyether ether ketone resin as a base resin.

6. The valve seat of a disc valve device according to claim 5, wherein the resin composition contains at least one of polytetrafluoroethylene resin and a spherical filler.

7. The valve seat of a disc valve device according to claim 5, wherein the resin composition does not contain a fibrous filler.

8. A method for manufacturing a valve seat made of synthetic resin for a disk valve device which switches a flow path and a flow rate of a fluid by sliding a valve body with respect to the valve seat,

one surface of the valve seat is a sliding surface sliding with the valve core, the other surface is a fixing surface fixed on the shell through a gasket,

The manufacturing method is characterized by comprising a polishing step of polishing both surfaces of an object to be polished to form the sliding surface and the fixed surface, wherein a difference between a polishing area on the sliding surface side and a polishing area on the fixed surface side of the object to be polished is within-20% to 20% of the polishing area on the sliding surface side.

9. The method of manufacturing a valve seat according to claim 8, wherein polishing in the polishing step is performed simultaneously on both surfaces of the polishing target.

10. The method of manufacturing a valve seat according to claim 9, wherein the polishing in the polishing step is performed by a double-sided grinder.

11. A method of manufacturing a valve seat according to claim 8,

the manufacturing method includes a molding step of injection molding a resin composition to obtain a molded body to be the polishing object, before the polishing step, wherein the molded body is formed such that a polishing area on the fixed surface side is larger than a polishing area on the sliding surface side.

12. The method of manufacturing a valve seat according to claim 11, wherein the molded body has a recess formed in a surface of the molded body on the fixed surface side, the recess being formed deeper than a polishing margin of the surface.

13. A disk valve device comprising a valve seat, a valve body, and a packing in contact with the valve seat in a housing,

the valve seat is as claimed in claim 1.

14. A disk valve which is a synthetic resin disk valve used in a disk valve device for switching a flow path and a flow rate of a fluid and which slides with a disk valve on the opposite side,

the sliding surface of the disk valve is a grinding surface formed with a concave portion, the concave portion is at least one of a groove portion and a hole portion for introducing the fluid,

the disc valve has an inclined portion inclined by 10 DEG to 25 DEG with respect to the polishing surface around an opening portion of the recess portion of the polishing surface.

15. A disc valve according to claim 14,

the width of the inclined portion of the polishing surface is in the range of 5 μm to 500 μm.