Valve body, flow path switching valve, and automotive heat medium system

Abstract

To provide a valve element capable of suppressing occurrence of cracks and fissures on a synthetic resin forming a valve body near a press-fit fixed cylinder into which a drive shaft is press-fitted, and a flow path switching valve using the valve body.SOLUTION: A valve element that changes a communication state of a flow path through which liquid flows, comprises: a valve body made of synthetic resin, and comprising a press-fit fixed cylinder 41 made of metal inside; and a drive shaft 23 that is press-fitted and fixed into the press-fit fixed cylinder of the valve body, where a non-press-fit part 47 composed of a space having a predetermined shape is formed in one or both of the press-fit fixed cylinder and the drive shaft. Even when the press-fit fixed cylinder is deformed by the press-fitting of the drive shaft, the deformation can be absorbed by the non-press-fit part, and therefore, it is possible to suppress cracks and fissures on the synthetic resin forming the valve body in the vicinity of the press-fit fixed cylinder into which the drive shaft is press-fit.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a valve body provided in a liquid flow path, a flow path switching valve using this valve body, and a heat medium system using this flow path switching valve. For example, it relates to a valve body used for distributing cooling water for cooling heat sources such as internal combustion engines and lithium batteries to various heat auxiliary devices, a flow path switching valve using this valve body, and an automotive heat medium system using this flow path switching valve.

Background Art

[0002] In a general automobile, for the purpose of circulating cooling water to a radiator to dissipate the heat of the cooling water for cooling the internal combustion engine to the outside, or circulating high-temperature cooling water to a heating device to heat the interior of the vehicle, a flow path switching valve is used to distribute the cooling water to various heat auxiliary devices.

[0003] As a flow path switching valve for distributing the cooling water for cooling the internal combustion engine of such an automobile to various heat auxiliary devices, for example, it is described in Japanese Unexamined Patent Application Publication No. 2018-66402 (Patent Document 1). The flow path switching valve described in this Patent Document 1 is a rotary type flow path switching valve that rotatably accommodates a bottomed cylindrical valve body having a closing wall on one side and an opening on the other side in a housing main body, and switches the flow path according to the rotational position of this valve body. It opens by the overlap between the opening of the communication passage formed in the housing main body and the opening formed on the outer peripheral portion of the valve main body, and distributes the cooling water flowing in from the inlet, which is the open end of the valve main body, to various heat auxiliary devices of the automobile through the opening of the valve main body and the communication passage of the housing main body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the valve body used for the flow path switching valve as shown in FIGS. 10 and 11 of Patent Document 1, a drive shaft made of metal is press-fitted into a valve body made of synthetic resin and integrated. Here, in a configuration where a metal drive shaft is directly press-fitted into a synthetic resin valve body, it is difficult to obtain sufficient fixing force between the two.

[0006] Therefore, a press-fitting fixing cylinder (metal insert) made of metal is insert-molded and integrated with a valve body made of synthetic resin, and a metal drive shaft is press-fitted over the entire length of this press-fitting fixing cylinder to firmly fix the drive shaft and the valve body. Note that a retaining means or the like is formed around the outer periphery of the press-fitting fixing cylinder so as not to fall off from the valve body.

[0007] When a metal drive shaft is press-fitted into a metal press-fitting fixing cylinder, the press-fitting fixing cylinder is pushed and expanded outward in the outer peripheral direction by the movement of the drive shaft in the press-fitting process. Therefore, since the metal press-fitting fixing cylinder deforms so as to swell, it is necessary to absorb this deformation with the synthetic resin valve body. However, in the synthetic resin forming the valve body, it is not very possible to absorb the deformation of the press-fitting fixing cylinder.

[0008] For this reason, there has been a problem that the synthetic resin outside the press-fitting fixing cylinder cracks or breaks, resulting in poor product yield. In particular, cracks and fractures tend to occur in the strength reduction regions (for example, weld portions, void portions, gas accumulation portions) due to mold forming when the press-fitting fixing cylinder is integrally molded.

[0009] An object of the present invention is to provide a valve body capable of suppressing cracks and fractures in the synthetic resin forming the valve body near the press-fitting fixing cylinder into which the drive shaft is press-fitted, a flow path switching valve using this valve body, and an automotive heat medium system using this flow path switching valve.

Means for Solving the Problems

[0010] The main feature of the present invention is a valve body that changes the communication state of a flow path through which a liquid flows. The valve body is formed of a synthetic resin and includes a valve body main body having a press-fitting and fixing cylinder made of metal inside, and a drive shaft press-fitted and fixed to the press-fitting and fixing cylinder of the valve body main body. A non-press-fitting portion formed of a space having a predetermined shape is formed in either one or both of the press-fitting and fixing cylinder and the drive shaft.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a valve body that suppresses the occurrence of cracks and fissures in the synthetic resin forming the valve body main body near the press-fitting and fixing cylinder into which the drive shaft is press-fitted, and a flow path switching valve using the same.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples within the technical concept of the present invention are also included in its scope.

[0014] Before explaining the embodiments of the present invention, the configuration of a flow path switching valve to which the present invention is applied will be described with reference to FIGS. 1 to 9. As described above, in the following description, the case of using the cooling water of an internal combustion engine as the heat medium is exemplarily shown. However, the present invention is not limited to the cooling water of an internal combustion engine, and is also applicable to a heat medium for cooling a heat source such as a lithium battery.

[0015] In FIG. 1, cooling water is supplied from a cooling water pump 02 to a cylinder jacket of an internal combustion engine 01. The cooling water that has cooled the cylinder jacket is sent to a flow path switching valve 10, and a part of it is returned to the suction side of the cooling water pump 02 again for constant circulation via a thermostat. The remaining cooling water is sent to heat auxiliary devices such as a heating device 03, a radiator 04, and an oil cooler 05. Note that these heat auxiliary devices are shown by way of example, and other heat auxiliary devices may be used.

[0016] And the distribution of the cooling water to these heat auxiliary devices is controlled by an electronic flow path switching means 06. For example, water temperature information from a water temperature sensor 07 provided in the flow path switching valve 10, operation state information of the internal combustion engine 01, and operation state information of various operation devices in the vehicle interior are input to the electronic flow path switching means 06, and the flow path to each heat auxiliary device is switched according to a control signal calculated by the electronic flow path switching means 06.

[0017] As will be described later, an electric motor is built into the flow path switching valve 10, and the rotation of this electric motor is controlled by a control signal from the electronic flow path switching means 06. A valve body is fixed to the electric motor, and by rotating the valve body, cooling water is made to flow through a communication path connected to each heat auxiliary device formed in the flow path switching valve 10, and the cooling water from the internal combustion engine is distributed to each heat auxiliary device.

[0018] FIG. 2 shows the appearance of the flow path switching valve 10. A connection pipe 12A connected to the cylinder jacket, a connection pipe 12B connected to the heating device 03, a connection pipe 12C connected to the radiator 04, and a connection pipe 12D connected to the oil cooler 05 are provided on a housing body 11. Also, cooling water flows into the flow path switching valve 10 from the internal combustion engine 01, and the cooling water is distributed to the connection pipes 12A to 12D by a valve body provided inside the housing body 11.

[0019] The flow path switching valve 10 is provided with a cover 17 that covers a thermostat filled with wax, and controls the cooling water flowing through the connection pipe 12A according to the temperature. Further, electronic flow path switching means 06 is fixed to the top of the housing body 11 of the flow path switching valve 10, and controls an electric motor housed inside the housing body 11.

[0020] FIG. 3 shows the configuration of the flow path switching valve 10 shown in FIG. 2 when disassembled and viewed obliquely. The housing body 11 is formed with a valve housing portion (see FIGS. 6 and 7, etc.) that houses a hollow cylindrical valve body 14, and a motor housing portion 16 that houses an electric motor 15. Further, the electronic flow path switching means 06 is fixed to the housing body 11 from the outside by fixing bolts, and is configured in a so-called integrated electromechanical type.

[0021] Furthermore, around the housing body 11, a connection pipe 12A connected to the cylinder jacket, a connection pipe 12B connected to the heating device 03, a connection pipe 12C connected to the radiator 04, and a connection pipe 12D connected to the oil cooler 05 are attached. Note that a cover 17 that covers the thermostat 13 is integrally formed on the connection pipe 12C. Here, a seal member 18 and a compression spring 19 are disposed between the housing body 11 and each of the connection pipes 12B to 12D. The seal member 18 is formed in a circular cylindrical shape with both ends open, and its front end surface is pressed against and in contact with the outer peripheral portion 20 of the valve body 14 by the compression spring 19.

[0022] The valve body 14 is formed of a synthetic resin formed in a bottomed cylindrical shape, and openings 21 connected to the above-described connection pipes 12A to 12D are formed in its outer peripheral portion 20. Therefore, the cooling water pumped from the cooling water pump 02 and flowing from the internal combustion engine as indicated by the arrow CA flows out to the connection pipes 12A to 12B through the openings 21.

[0023] On one side of the valve body 14, a closing wall 22 is provided. This closing wall 22 is fixed to the drive shaft 23 and is rotated within the valve housing of the housing body 11 in synchronization with the rotation of the drive shaft 23. In synchronization with this rotation, the valve body 14 selects the connection relationship with each connection pipe 12A - 12D (switches the flow path). Incidentally, since the degree of overlap between the opening 21 and the opening of the sealing member 18 can be controlled according to the rotational state of the valve body 14, it may also operate to control the flow rate.

[0024] The electric motor 15 and the valve body 14 are connected by a worm gear mechanism. That is, a worm wheel 24 is fixed to the end of the drive shaft 23 opposite to the side where the valve body 14 is fixed, and this worm wheel 24 meshes with a worm 25 formed on one side of the worm shaft. Also, a worm wheel 26 formed on the other side of the worm shaft meshes with a worm 27 fixed to the electric motor 15. Therefore, when the electric motor 15 rotates, this rotation is transmitted to the drive shaft 23 through the worm 27 ⇒ worm wheel 26 ⇒ worm 25 ⇒ worm wheel 24, and finally rotates the valve body 14.

[0025] Also, a cover provided with an electronic flow path switching means 06 is fixed to the housing body 11 so as to cover the electric motor 15 and the worm gear mechanism. The control signal from the electronic flow path switching means 06 is given to the electric motor 15 to operate it to perform a predetermined rotational operation.

[0026] Figs. 4 and 5 show the configuration of the valve body 14, which is entirely made of synthetic resin by injection molding. The valve body 14 is formed in a bottomed cylindrical shape with a closing wall 22 formed on one side and an opening 31 formed on the other side. A plurality of openings 21 are formed in the circular outer peripheral portion 20 of the valve body 14, which are selectively connected to the respective connection pipes 12A to 12D, and are configured to allow the cooling water flowing into the interior of the outer peripheral portion 20 from the opening 31 to flow out to the respective connection pipes 12A to 12D. The selection of the connection state between the openings 21 formed in the outer peripheral portion 20 and the respective connection pipes 12A to 12D is appropriately combined according to the heat repair devices to be connected.

[0027] The closing wall 22 is formed with a circular drive shaft fixing portion 32 that projects axially inward of the outer peripheral portion 20 near the center, and the drive shaft 23 shown in Fig. 3 is fixed to the drive shaft fixing portion 32. An insert-molded metal press-fitting fixing cylinder (see Fig. 8) is embedded in the drive shaft fixing portion 32, and the drive shaft 23 is press-fitted into this press-fitting fixing cylinder so that the valve body 14 and the drive shaft 23 are integrated (this configuration will be described with reference to Fig. 8). Therefore, the rotation of the electric motor 15 is decelerated and increased in force via the worm gear mechanism and applied to the drive shaft 23, and further rotates the valve body 14.

[0028] The closing wall 22 around the drive shaft fixing portion 32 is divided into two regions: a flat region portion 33 that is the first region portion and an inclined region portion 34 that is the second region portion. The inclined region portion 34 is formed in an inclined shape toward the opening 31 side of the valve body 14 with a predetermined inclination from the outer peripheral edge of the closing wall 22 toward the drive shaft fixing portion 32 located on the axis of the valve body 14. On the other hand, the flat region portion 33 is formed in a flat shape perpendicular to the axial direction along the radial direction of the valve body 14.

[0029] Therefore, a step is formed between the flat region portion 33 and the inclined region portion 34, and on this step portion, a first regulating wall 35Mi and a second regulating wall 35Mx that function as regulated portions and are formed in a substantially right-angled triangle shape when viewed in the axial direction are formed along the axial direction. The first regulating wall 35Mi and the second regulating wall 35Mx are formed radially in the radial direction and are in surface contact with a first regulating piece 39Mi and a second regulating piece 39Mx, which will be described later.

[0030] Further, since the first regulating wall 35Mi and the second regulating wall 35Mx extend inward from the flat region portion 33 toward the opening portion 31 side in the axial direction of the valve body 14, they do not affect the size of the internal shape of the valve housing portion 28.

[0031] Here, the first regulating wall 35Mi has a function of determining a first regulating position, which is an initial rotation position, in cooperation with a first regulating portion, which will be described later, and the second regulating wall 35Mx has a function of determining a second regulating position, which is a maximum rotation position, in cooperation with a second regulating portion, which will be described later. And although the angles of these regulating positions are arbitrary, they are determined to be about 170° at the angle of the flat region portion 33.

[0032] Also, although the inclined region portion 34 is formed, this inclined region portion 34 may be a flat region portion. A step is formed with the above-described flat region portion 33, and the first regulating wall 35Mi and the second regulating wall 35Mx may be formed in this portion. However, by forming the inclined region portion 34, it is easier for the cooling water to flow toward the communication passage 29 formed in the housing body 11.

[0033] Next, the configuration of the valve housing portion 28 in which the valve body 14 is housed will be described with reference to FIGS. 6 and 7.

[0034] In FIGS. 6 and 7, a valve housing portion 28 having a circular cross-section perpendicular to the axial direction is formed in the housing body 11. The valve housing portion 28 is composed of a cylindrical side wall 36 and an end wall 37 that closes one side of the side wall 36, and the opposite side of the end wall 37 is an open end. Therefore, in a state where the valve body 14 is housed in the valve housing portion 28, the closing wall 22 side of the valve body 14 is housed so as to face the end wall 37 of the valve housing portion 28.

[0035] Near the center of the end wall 37, a bearing fixing portion 38 extending axially inward toward the inside of the valve housing portion 28 is formed. By this bearing fixing portion 38, the drive shaft 23 shown in FIG. 3 is rotatably supported. Also, a first regulating piece 39Mi and a second regulating piece 39Mx that function as regulating portions and extend axially inward from the end wall 37 to a predetermined position of the bearing fixing portion 38 are integrally formed with the end wall 37.

[0036] The first regulating piece 39Mi and the second regulating piece 39Mx are formed in a plate shape, and their hypotenuses extend from a predetermined position in the axial direction of the bearing fixing portion 38 to the outer peripheral edge of the end wall 37, and are formed in a substantially right-angled triangle shape when viewed in the axial direction. Therefore, the shapes of the first regulating piece 39Mi and the second regulating piece 39Mx and the first regulating wall 35Mi and the second regulating wall 35Mx are substantially the same.

[0037] And in a state where the valve body 14 is incorporated into the valve housing portion 28, the first regulating piece 39Mi and the second regulating piece 39Mx are housed in the inclined region portion 34 of the valve body 14, and in the formation range of the inclined region portion 34, the rotation operation of the valve body 14 is not restricted. When the valve body 14 further rotates and comes into contact with the first regulating wall 35Mi and the second regulating wall 35Mx, the rotation operation of the valve body 14 is restricted.

[0038] As shown in FIG. 7, the first regulating piece 39Mi and the second regulating piece 39Mx extend radially in the radial direction from the center of the bearing fixing portion 38, and when they come into contact with the first regulating wall 35Mi and the second regulating wall 35Mx, they are in surface contact. Therefore, the stress acting per unit area of the regulating pieces 39Mi, 39Mx and the regulating walls 35Mi, 35Mx can be reduced, and the durability can be enhanced.

[0039] FIG. 8 shows the B-B cross section of FIG. 2, and FIG. 9 shows the C-C cross section of FIG. 2. In FIGS. 8 and 9, the valve body 14 is housed in a valve housing portion 28 formed in the housing body 11. A drive shaft 23 is fixed to a drive shaft fixing portion 32 of the valve body 14, and this drive shaft 23 is inserted through a bearing fixing portion 38 of the housing body 11 and is pivotally supported by a sliding bearing 40. Inside the drive shaft fixing portion 32 of the valve body 14, a cylindrical press-fitting fixing cylinder 41 made of metal is integrally formed by insert molding into the drive shaft fixing portion 32 made of synthetic resin.

[0040] A worm wheel 24 is fixed to an end portion of the drive shaft 23 on the opposite side of the portion where the valve body 14 is fixed, and rotational motion is transmitted from a worm 25. These worm wheel 24 and worm 25 are hermetically covered by a cover 42 provided with an electronic flow path switching means 06. Further, an annular sliding bearing 43 is fitted and fixed to the inner peripheral surface on the open end side of the valve housing portion 28 of the housing body 11, and slidably supports the outer peripheral portion 20 of the open portion 31 of the valve body 14.

[0041] Furthermore, a pressure relief passage 44 is formed in an end face wall portion 37 facing the inclined region portion 34 of the valve body 14, which communicates the space formed by the sliding bearing 40 of the bearing fixing portion 38, the housing body 11, and the cover 42. Thereby, the pressure near the sliding bearing 40 is released to the atmosphere side.

[0042] Here, as shown in FIG. 9, since the communication passage 29 to which the connection pipe 12B connected to the heating device 03 is attached is formed near the end face wall 37, in order to smooth the flow of the cooling water, the communication passage 29 is formed within the operating range of the inclined region portion 34 of the valve body 14 so as to reduce the flow path resistance. Therefore, since the cooling water can flow into the communication passage 29 along the inclined surface of the inclined region portion 34, it can flow smoothly into the communication passage 29 without being greatly affected by the flow path resistance at this portion.

[0043] In the above, the cooling water CA from the internal combustion engine flows through the connection pipe 12C toward the radiator 04 and through the connection pipe 12D toward the oil cooler 05 in FIG. 8. Similarly, as shown in FIG. 9, the cooling water CA from the internal combustion engine flows through the connection pipe 12B toward the heating device 03. Incidentally, these connection pipes 12A to 12D and the respective openings 21 formed in the valve body 14 are selectively connected according to the rotational state of the valve body 14.

[0044] By the way, as shown in FIGS. 8 and 9, the drive shaft 23 is press-fitted into the press-fitting fixing cylinder 41 embedded in the drive shaft fixing portion 32 over the entire axial length of the press-fitting fixing cylinder 41. When the metal drive shaft 23 is press-fitted into the metal press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 is pushed outward in the outer peripheral direction by the movement of the drive shaft 23 in the press-fitting process. For this reason, since the metal press-fitting fixing cylinder 41 deforms so as to bulge, it is necessary to absorb this deformation with the synthetic resin valve body 14. However, the synthetic resin forming the valve body 14 cannot be expected to deform enough to absorb the deformation of the press-fitting fixing cylinder. For this reason, there has been a problem that the synthetic resin outside the press-fitting fixing cylinder 41 cracks or breaks, resulting in poor product yield.

[0045] Therefore, in the present invention, in order to suppress cracks and fissures from occurring in the synthetic resin forming the drive shaft fixing portion 32 near the press-fitting fixing cylinder 41 into which the drive shaft 23 is press-fitted, a press-fitting fixing cylinder 41 embedded in the drive shaft fixing portion 32 formed of synthetic resin and a drive shaft 23 press-fitted into the press-fitting hole of the press-fitting fixing cylinder 41 are provided. A configuration is proposed in which a non-press-fitting portion formed of a space having a predetermined shape for releasing the deformation of the press-fitting fixing cylinder caused by the press-fitting of the drive shaft 23 is provided on one or both of the press-fitting fixing cylinder 41 and the drive shaft 23 that are offset from each other. Hereinafter, typical embodiments of the present invention will be described.

Example

[0046] Next, a first embodiment of the present invention will be described with reference to FIG. 10. In this embodiment, the drive shaft 23 is press-fitted into the middle of the press-fitting fixing cylinder 41, and a non-press-fitting portion 47 is formed between the tip surface 23F of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41 to release the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23. In the following embodiments, the portion where the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41 are in contact will be treated as the "press-fitting region" and the description will proceed.

[0047] In FIG. 10, a sliding bearing 40 is provided inside the bearing fixing portion 38, and the drive shaft 23 is rotatably supported by this sliding bearing 40. The drive shaft 23 is made of metal, and in this embodiment, it is made of a stainless steel material containing no zinc. A sealing material 45 is interposed in the bearing fixing portion 38 on the valve body 14 side of the sliding bearing 40. Similarly, a sealing material 46 is interposed in the bearing fixing portion 38 on the side opposite to the valve body 14 of the sliding bearing 40. This prevents cooling water from leaking to the cover 42 side.

[0048] At the center of the synthetic resin valve body 14, a frustum-shaped drive shaft fixing portion 32 is formed, and near the center thereof, a metal press-fitting fixing cylinder 41 is integrally embedded by insert molding. An annular projection 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, whereby the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0049] And the drive shaft 23 is press-fitted and fixed into the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference. However, the tip surface 23F on the press-fitting side of the drive shaft 23 does not reach the tip surface 41F of the press-fitting fixing cylinder 41, and it is not press-fitted all the way to the middle of the press-fitting fixing cylinder 41 to form a non-press-fitted portion 47 having a predetermined distance (D1).

[0050] The reason is that by forming the non-press-fitted portion 47 which is a space of a predetermined shape formed by the press-fitting hole 41H between the tip surface 23F of the drive shaft 23 and the tip surface 41F of the press-fitting fixing cylinder 41, it has a function of relieving the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Incidentally, the predetermined shape is not particularly limited as long as it has a function of relieving the deformation of the press-fitting fixing cylinder 41. The same applies to the following other embodiments.

[0051] That is, when the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 expands and deforms due to the press-fitting of the drive shaft 23, but this deformation is absorbed by the non-press-fitted portion 47 which is a space of a predetermined shape, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be relieved. Thereby, it is possible to suppress the occurrence of cracks and breaks in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0052] In particular, when insert molding the press-fitting fixing cylinder 41 with the drive shaft fixing portion 32, synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fissures are likely to occur. Therefore, in the present embodiment, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a non-press-fitting portion 47 is formed to release the force due to the deformation and expansion of the press-fitting fixing cylinder 41 by press-fitting, so that the occurrence of cracks and fissures in the strength reduction region can be suppressed.

[0053] In addition, the axial length (D1) of the drive shaft 23 of the non-press-fitting portion 47 only needs to be determined to ensure the fixing force by press-fitting and to release the force due to the deformation and expansion of the drive shaft 23 by press-fitting.

Example

[0054] Next, a second embodiment of the present invention will be described with reference to FIG. 11. In this embodiment, the drive shaft 23 from the middle to the tip surface 23F to be press-fitted is made thinner to form a small-diameter portion 48, and between the small-diameter portion 48 of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, a non-press-fitting portion 49 is formed to release the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23.

[0055] In addition, in FIG. 11, the same reference numerals as those in FIG. 10 indicate the same components, and their functions are also the same. Therefore, duplicate descriptions may be omitted.

[0056] In FIG. 11, a frustum-shaped drive shaft fixing portion 32 is formed at the center of a valve body 14 made of synthetic resin, and a press-fitting fixing cylinder 41 made of metal is integrally embedded near the center thereof by insert molding. An annular projection 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, whereby the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0057] And the drive shaft 23 is press-fitted and fixed into the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference fit. However, between the midway point on the press-fitting side to the tip surface 23F in the press-fitting region of the drive shaft 23, a small-diameter portion 48 with a predetermined length (D2) is provided, and a non-press-fitting portion 49 formed of an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 49 is rectangular. Note that such an annular space is also an example of a predetermined shape.

[0058] In this way, by forming the non-press-fitting portion 49 formed of the annular space between the press-fitting hole 41H of the press-fitting fixing cylinder 41 and the small-diameter portion 48 from the midway point of the drive shaft 23 to the tip surface 23F, a function of releasing the force generated by the deformation of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23 is provided. Note that the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fitting fixing cylinder 41 and is in a flush relationship.

[0059] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 expands and deforms due to the press-fitting of the drive shaft 23, but this deformation is absorbed by the non-press-fitting portion 49 formed of the annular space, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. Thereby, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0060] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fissures are likely to occur. For this reason, in this embodiment, a non-press-fitting portion 49 that releases the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23 is formed between the small-diameter portion 48 located on the tip side of the drive shaft fixing portion 32 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, so that the occurrence of cracks and fissures in the strength reduction region can be suppressed.

Example

[0061] Next, a third embodiment of the present invention will be described with reference to FIG. 12. In this embodiment, a tapered portion 50 is formed by gradually shortening the diameter from the middle to the tip surface 23F of the drive shaft 23 to be press-fitted, and a non-press-fitting portion 51 that releases the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23 is formed between the tapered portion 50 of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41.

[0062] In addition, in FIG. 12, the same reference numerals as those in FIG. 10 indicate the same components, and their functions are also the same. Therefore, duplicate explanations may be omitted.

[0063] In FIG. 12, a conical frustum-shaped drive shaft fixing portion 32 is formed in the central portion of the valve body 14 made of synthetic resin, and a metal press-fitting fixing cylinder 41 is integrally embedded by insert molding in the vicinity of the central portion thereof. An annular protrusion 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, so that the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the side opposite to the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the side opposite to the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0064] The drive shaft 23 is press-fitted and fixed into the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference fit. However, between the middle of the press-fitting side of the press-fitting region of the drive shaft 23 and the tip surface 23F, it is formed as a tapered portion 50 having a predetermined length (D3) whose diameter gradually decreases, and a non-press-fitting portion 51 formed of an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 51 is triangular. Note that such an annular space is also an example of a predetermined shape.

[0065] In this way, by forming the non-press-fitting portion 51 formed of the annular space by the tapered portion 50 between the middle of the drive shaft 23 and the tip surface 23F, it has a function of releasing the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Note that the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fitting fixing cylinder 41 and is flush.

[0066] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 undergoes expansion and deformation due to the press-fitting of the drive shaft 23, but this deformation is absorbed by the non-press-fitting portion 51 formed of the annular space, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress cracks and fractures from occurring in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0067] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fractures are likely to occur. Therefore, in this embodiment, by forming the non-press-fitting portion 51 that releases the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23 between the tapered portion 50 on the tip side of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, it is possible to suppress the occurrence of cracks and fractures in the strength reduction region.

Example

[0068] Next, a fourth embodiment of the present invention will be described with reference to FIG. 13. In this embodiment, a small-diameter portion 52 is provided in the middle of the drive shaft 23, and a press-fitting portion 53 is formed again on the tip side of this portion. Further, the diameter is gradually reduced from this point to the tip surface 23F at the tip to form a tapered portion 55. And, between the small-diameter portion 52 of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, and between the tapered portion 55 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, non-press-fitting portions 53 and 56 are formed to release the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23.

[0069] In addition, in FIG. 13, the same reference numerals as those in FIG. 10 indicate the same parts, and since their functions are also the same, duplicate explanations may be omitted.

[0070] In FIG. 13, a conical drive shaft fixing portion 32 is formed at the center of the synthetic resin valve body 14, and a metal press-fitting fixing cylinder 41 is integrally embedded by insert molding near the center thereof. An annular protrusion 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, whereby the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0071] And, the drive shaft 23 is press-fitted and fixed in the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference fit. However, a small-diameter portion 52 is formed over a predetermined length (D4) in the middle of the press-fitting side of the drive shaft 23, and a press-fitting portion 53 is formed again at the tip thereof. And, a non-press-fitting portion 54 formed of an annular space is formed between the small-diameter portion 52 and the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 54 is rectangular. Note that such an annular space is also an example of a predetermined shape.

[0072] Further, from this press-fitting portion 53 to the tip surface 23F of the drive shaft 23, a tapered portion 55 is formed over a predetermined length (D5), and a non-press-fitting portion 56 having an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 56 is substantially triangular.

[0073] In this way, by forming the non-press-fitting portion 54 formed by the small-diameter portion 52 and having an annular space between the middle of the drive shaft 23 and the tip surface 23F, and the non-press-fitting portion 56 formed by the tapered portion 55 from the press-fitting portion 53 to the tip surface 23F and having an annular space, it has a function of releasing the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Incidentally, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fitting fixing cylinder 41 and is flush with it.

[0074] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 expands and deforms due to the press-fitting of the drive shaft 23. This deformation is absorbed by the non-press-fitting portion 54 and the non-press-fitting portion 56 having an annular space, and the force caused by the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0075] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a weld portion, a void portion, a gas accumulation portion) is generated, and cracks and fractures are likely to occur. For this reason, in this embodiment, by forming a non-press-fitting portion 56 that releases the force caused by the deformation and expansion of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23 between the tapered portion 55 on the tip side of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, the occurrence of cracks and fractures in the strength reduction region can be suppressed.

[0076] Furthermore, in the present embodiment, a non-press-fitting portion 54 is also formed near the axial center of the press-fitting fixing cylinder 41 (here, the region where the annular protrusion 41P for preventing detachment exists). Therefore, by forming the press-fitting portion 53 on the tip side of the drive shaft 23, even if the press-fitting fixing cylinder 41 expands and deforms, the non-press-fitting portion 54 absorbs the force due to the expansion and deformation, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

Example

[0077] Next, a fifth embodiment of the present invention will be described with reference to FIG. 14. In this embodiment, a press-fitting portion 57 is formed in the middle of the drive shaft 23 to be press-fitted, and the drive shaft 23 on the bearing fixing portion 38 side (the side opposite to the tip of the drive shaft) from this press-fitting portion 57 is made into a small-diameter portion 58. Further, from the press-fitting portion 57 to the tip surface 23F, the diameter is gradually reduced to form a tapered portion 59. Between the small-diameter portion 58 of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, and between the tapered portion 59 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, non-press-fitting portions 60 and 61 for releasing the force generated by the deformation of the press-fitting fixing cylinder 41 due to the press-fitting portion 57 of the drive shaft 23 are formed.

[0078] In addition, in FIG. 14, the same reference numerals as those in FIG. 10 indicate the same components, and since their functions are also the same, duplicate explanations may be omitted in some cases.

[0079] In FIG. 14, a frustum-shaped drive shaft fixing portion 32 is formed in the central portion of the valve body 14 made of synthetic resin, and a metal press-fitting fixing cylinder 41 is integrally embedded by insert molding near the central portion thereof. An annular protrusion 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, and thus, the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the side opposite to the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the side opposite to the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0080] And in the middle of the drive shaft 23, here a press-fitting portion 57 is formed on the tip side. This press-fitting portion 57 is press-fitted and fixed into the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference fit. And the drive shaft 23 on the side of the bearing fixing portion 38 from the press-fitting portion 57 is made into a small-diameter portion 58, and a non-press-fitting portion 60 with a predetermined length (D6) formed of an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 60 is rectangular. Incidentally, such an annular space is also an example of a predetermined shape.

[0081] Also, between the press-fitting portion 57 formed in the middle of the drive shaft 23 and the tip surface 23F, it is made into a tapered portion 59 with a predetermined length (D7) whose diameter gradually becomes shorter, and a non-press-fitting portion 61 formed of an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 61 is triangular.

[0082] In this way, by making the drive shaft 23 on the side of the fixing portion 58 from the press-fitting portion 57 formed in the middle of the drive shaft 23 into a small-diameter portion 58, forming a non-press-fitting portion 60 formed of an annular space by the small-diameter portion 58, and a non-press-fitting portion 61 formed of an annular space by the tapered portion 50 from the press-fitting portion 57 to the tip surface 23F, it has a function of releasing the force generated by the deformation of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23. Incidentally, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fitting fixing cylinder 41 and is in a flush relationship.

[0083] And when the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 undergoes expansion and deformation due to the press-fitting of the drive shaft 23, but this deformation is absorbed by the non-press-fitting portions 60 and 61 formed of annular spaces, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. Thereby, it is possible to suppress the occurrence of cracks and breaks in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0084] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fissures are likely to occur. Therefore, in this embodiment, between the tapered portion 59 on the tip side of the drive shaft 23 and the press-fitting hole 41H of the press-fitting fixing cylinder 41, a non-press-fitting portion 61 is formed to release the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23, thereby suppressing the occurrence of cracks and fissures in the strength reduction region.

[0085] Furthermore, in this embodiment, a non-press-fitting portion 60 is also formed on the side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41. Therefore, by forming the press-fitting portion 57 on the tip side of the drive shaft 23, even if the press-fitting fixing cylinder 41 expands and deforms, the force due to the expansion and deformation is absorbed by the non-press-fitting portion 60, and the force due to the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fissures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

Example

[0086] Next, a sixth embodiment of the present invention will be described with reference to FIG. 15. This embodiment is characterized in that a space is formed from the tip surface 23F of the drive shaft 23 to be press-fitted along the axis of the drive shaft 23 toward the bearing fixing portion 38 to form a non-press-fitting portion 62, thereby releasing the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23.

[0087] In addition, in FIG. 15, the same reference numerals as those in FIG. 10 indicate the same components, and their functions are also the same. Therefore, duplicate explanations may be omitted.

[0088] In Fig. 15, a frustum-shaped drive shaft fixing portion 32 is formed at the center of a valve body 14 made of synthetic resin, and a press-fit fixing cylinder 41 made of metal is integrally embedded near the center thereof by insert molding. An annular protrusion 41P for preventing detachment is formed on the outer peripheral portion of the press-fit fixing cylinder 41, whereby the press-fit fixing cylinder 41 is configured not to drop off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fit fixing cylinder 41 are in a positional relationship of the same plane (so-called flush surface). By forming a space along the axis of the drive shaft 23 toward the bearing fixing portion 38 to form a non-press-fitting portion 62, And a space serving as the non-press-fitting portion 62 is formed from the tip surface 23F of the drive shaft 23 along the axis of the drive shaft 23 toward the bearing fixing portion 38. The space serving as the non-press-fitting portion 62 has a depth of a predetermined length (D8) along the axis of the drive shaft 23 and has a diameter shorter than the diameter of the drive shaft 23. Also, the space formed in the drive shaft 23 is an example of a predetermined shape.

[0089] Thus, by forming the non-press-fitting portion 62 formed by the space formed at the tip portion of the drive shaft 23, it has a function of releasing the force generated by the deformation of the press-fit fixing cylinder 41 due to the press-fitting of the drive shaft 23. Incidentally, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fit fixing cylinder 41 and is in a flush relationship.

[0090] When the drive shaft 23 is press-fitted into the press-fit hole 41H of the press-fit fixing cylinder 41, the press-fit fixing cylinder 41 undergoes expansion and deformation due to the press-fitting of the drive shaft 23, but this deformation is absorbed by the non-press-fitting portion 62 formed by the space formed in the drive shaft 23, and the force due to the deformation of the press-fit fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fit fixing cylinder 41 can be released. Thereby, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fit fixing cylinder 41 of the drive shaft fixing portion 32.

[0091] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through the gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fissures are likely to occur. Therefore, in this embodiment, by forming a non-press-fitting portion 62 on the tip side of the drive shaft 23 to release the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23, the occurrence of cracks and fissures in the strength reduction region can be suppressed.

[0092] In addition, the non-press-fitting portion 63 formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41 by the tapered portion formed at the tip of the drive shaft 23 can exhibit the same operations and effects as those of the other embodiments described above.

[0093] In several embodiments described above, a non-press-fitting portion having a predetermined shape is formed on the side of the drive shaft. However, a non-press-fitting portion having a predetermined shape can also be formed on the side of the press-fitting fixing cylinder. Hereinafter, an embodiment in which a non-press-fitting portion having a predetermined shape is formed on the side of the press-fitting fixing cylinder will be described. The same reference numerals denote the same components, and their functions are also the same, so duplicate explanations may be omitted.

Example

[0094] Next, a seventh embodiment of the present invention will be described with reference to FIG. 16. In this embodiment, a non-press-fitting portion 64 formed of an annular space surrounding the tip portion of the drive shaft 23 is formed on the tip surface 41F of the press-fitting fixing cylinder 41 into which the drive shaft 23 is press-fitted, in order to release the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23.

[0095] In addition, in FIG. 16, the same reference numerals as those in FIG. 10 denote the same components, and their functions are also the same, so duplicate explanations may be omitted.

[0096] In FIG. 16, a frustum-shaped drive shaft fixing portion 32 is formed at the center of a valve body 14 made of synthetic resin, and a press-fitting fixing cylinder 41 made of metal is integrally embedded near the center thereof by insert molding. An annular projection 41P for preventing detachment is formed on the outer peripheral portion of the press-fitting fixing cylinder 41, whereby the press-fitting fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0097] The drive shaft 23 is press-fitted and fixed into the press-fitting hole 41H of the press-fitting fixing cylinder 41 with a predetermined interference. And the press-fitting hole 41H of the press-fitting fixing cylinder 41 located between the middle of the drive shaft 23 and the tip surface 23F has a predetermined length (D8) with respect to the drive shaft 23 and is an enlarged hole 41E-1 having a predetermined diameter forming an annular space. That is, the diameter of the enlarged hole 41E-1 of the press-fitting fixing cylinder 41 is set larger than the diameter of the drive shaft 23, whereby an annular space is formed. Incidentally, such an annular space is also an example of a predetermined shape.

[0098] This annular space becomes a non-press-fitting portion 64 that releases the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23 described above, and can suppress the occurrence of cracks and fissures in the strength reduction region. Thus, by forming the non-press-fitting portion 64 composed of the annular space formed by the enlarged hole 41E-1 between the middle of the drive shaft 23 and the tip surface 23F, it has a function of releasing the force generated by the deformation of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Incidentally, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fitting fixing cylinder 41 and is in a flush relationship.

[0099] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 expands and deforms due to the press-fitting of the drive shaft 23. However, this deformation is absorbed by the non-press-fitting portion 64 formed by the annular space of the press-fitting fixing cylinder 41, and the force caused by the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing on the outer periphery of the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0100] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fractures are likely to occur. Therefore, in this embodiment, by forming a non-press-fitting portion 64 on the side of the enlarged hole 41E-1 of the drive shaft 23 and the press-fitting fixing cylinder 41 to release the force caused by the deformation and expansion of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23, the occurrence of cracks and fractures in the strength reduction region can be suppressed.

Example

[0101] Next, the eighth embodiment of the present invention will be described with reference to FIG. 17. In this embodiment, in the vicinity of the axial center of the press-fitting fixing cylinder 41 into which the drive shaft 23 is press-fitted, a non-press-fitting portion 65 formed by an annular space surrounding the drive shaft 23 is formed to release the force generated by the deformation of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23.

[0102] In addition, in FIG. 17, the same reference numerals as those in FIG. 10 indicate the same components, and their functions are also the same. Therefore, duplicate explanations may be omitted.

[0103] In Fig. 17, a frustum-shaped drive shaft fixing portion 32 is formed at the center of a valve body 14 made of synthetic resin, and a press-fit fixing cylinder 41 made of metal is integrally embedded near the center thereof by insert molding. An annular projection 41P for preventing detachment is formed on the outer peripheral portion of the press-fit fixing cylinder 41, whereby the press-fit fixing cylinder 41 is configured not to fall off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fit fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0104] The drive shaft 23 is press-fitted and fixed into the press-fit hole 41H of the press-fit fixing cylinder 41 with a predetermined interference. The press-fit hole 41H of the press-fit fixing cylinder 41 located in the middle of the drive shaft 23 has a predetermined length (D9) between it and the drive shaft 23 and is an enlarged hole 41E-2 having a predetermined diameter that forms an annular space. That is, the diameter of the enlarged hole 41E-2 of the press-fit fixing cylinder 41 is set larger than the diameter of the drive shaft 23, whereby an annular space of length (D9) is formed. Incidentally, such an annular space is also an example of a predetermined shape.

[0105] This annular space becomes a non-press-fitting portion 65 that releases the force due to the deformation and expansion of the press-fit fixing cylinder 41 caused by the press-fitting of the drive shaft 23 described above, and can suppress the occurrence of cracks and fissures in the synthetic resin around the press-fit fixing cylinder 41. Thus, by forming a non-press-fitting portion 64 consisting of an annular space formed by the enlarged hole 41E-2 in the middle of the drive shaft 23, it has a function of releasing the force generated by the deformation of the press-fit fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Incidentally, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fit fixing cylinder 41 and is in a flush relationship.

[0106] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 undergoes expansion and deformation due to the press-fitting of the drive shaft 23. However, this deformation is absorbed by the non-press-fitting portion 65 formed by the annular space of the press-fitting fixing cylinder 41, and the force caused by the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing around the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0107] Also, similar to the embodiment shown in FIGS. 13 and 14, between the tip end surface 23F of the drive shaft 23, a tapered portion 66 having a predetermined length with a gradually decreasing diameter is provided, and a non-press-fitting portion 67 formed by an annular space is formed between the tapered portion 66 and the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section of the non-press-fitting portion 61 along the axial direction is triangular.

[0108] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, the synthetic resin is injected through a gate from the side opposite to the tip end surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip end surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fractures are likely to occur. Therefore, in this embodiment, by forming a non-press-fitting portion 67 that releases the force caused by the deformation and expansion of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23, the occurrence of cracks and fractures in the strength reduction region can be suppressed.

Example

[0109] Next, a ninth embodiment of the present invention will be described with reference to FIG. 18. In this embodiment, on the side of the bearing fixing portion 38 of the press-fitting fixing cylinder 41 into which the drive shaft 23 is press-fitted (the side opposite to the tip of the drive shaft), a non-press-fitting portion 68 formed by an annular space surrounding the drive shaft 23 is formed to release the force generated by the deformation of the press-fitting fixing cylinder 41 due to the press-fitting of the drive shaft 23.

[0110] Still, in FIG. 18, the same reference numerals as those in FIG. 10 denote the same components and have the same functions, so duplicate explanations may be omitted in some cases.

[0111] In FIG. 18, a frustum-shaped drive shaft fixing portion 32 is formed at the center of a valve body 14 made of synthetic resin, and a press-fit fixing cylinder 41 made of metal is integrally embedded by insert molding near the center thereof. An annular projection 41P for preventing detachment is formed on the outer peripheral portion of the press-fit fixing cylinder 41, so that the press-fit fixing cylinder 41 is configured not to drop off from the drive shaft fixing portion 32. The tip surface 32F on the opposite side of the bearing fixing portion 38 of the drive shaft fixing portion 32 and the tip surface 41F on the opposite side of the bearing fixing portion 38 of the press-fit fixing cylinder 41 are in a positional relationship of the same surface (so-called flush surface).

[0112] The drive shaft 23 is press-fitted and fixed into a press-fit hole 41H of the press-fit fixing cylinder 41 with a predetermined interference fit. The press-fit hole 41H of the press-fit fixing cylinder 41 on the side of the bearing fixing portion 38 of the drive shaft 23 is an enlarged hole 41E-3 having a predetermined length (D10) and a predetermined diameter forming an annular space between the drive shaft 23. That is, the diameter of the enlarged hole 41E-3 of the press-fit fixing cylinder 41 is set larger than the diameter of the drive shaft 23, thereby forming an annular space of length (D10). Still, such an annular space is also an example of a predetermined shape.

[0113] This annular space becomes a non-press-fitting portion 68 that releases the force due to the deformation and expansion of the press-fit fixing cylinder 41 caused by the press-fitting of the drive shaft 23 described above, and can suppress the occurrence of cracks and fractures in the synthetic resin around the press-fit fixing cylinder 41. In this way, by forming a non-press-fitting portion 64 composed of an annular space formed by the enlarged hole 41E-3 in the middle of the drive shaft 23, it has a function of releasing the force generated by the deformation of the press-fit fixing cylinder 41 caused by the press-fitting of the drive shaft 23. Still, the tip surface 23F of the drive shaft 23 reaches the tip surface 41F of the press-fit fixing cylinder 41 and is in a flush relationship.

[0114] When the drive shaft 23 is press-fitted into the press-fitting hole 41H of the press-fitting fixing cylinder 41, the press-fitting fixing cylinder 41 expands and deforms due to the press-fitting of the drive shaft 23. However, this deformation is absorbed by the non-press-fitting portion 68 formed by the annular space of the press-fitting fixing cylinder 41, and the force caused by the deformation of the press-fitting fixing cylinder 41 acting on the synthetic resin of the drive shaft fixing portion 32 existing around the press-fitting fixing cylinder 41 can be released. As a result, it is possible to suppress the occurrence of cracks and fractures in the synthetic resin located on the outer periphery of the press-fitting fixing cylinder 41 of the drive shaft fixing portion 32.

[0115] Also, similar to the embodiment shown in FIGS. 13 and 14, between the tip surface 23F of the drive shaft 23, it is formed as a tapered portion 69 having a predetermined length with a gradually decreasing diameter, and a non-press-fitting portion 70 formed of an annular space is formed between the press-fitting hole 41H of the press-fitting fixing cylinder 41. The cross-section along the axial direction of the non-press-fitting portion 70 is triangular.

[0116] Also in this embodiment, when the press-fitting fixing cylinder 41 is insert-molded with the drive shaft fixing portion 32, synthetic resin is injected through a gate from the side opposite to the tip surface 32F of the drive shaft fixing portion 32. However, on the side of the tip 32F of the drive shaft fixing portion 32 and the tip surface 41F of the press-fitting fixing cylinder 41, a strength reduction region (for example, a welded portion, a void portion, a gas accumulation portion) is generated, and cracks and fractures are likely to occur. For this reason, in this embodiment, by forming the non-press-fitting portion 70 that releases the force due to the deformation and expansion of the press-fitting fixing cylinder 41 caused by the press-fitting of the drive shaft 23, it is possible to suppress the occurrence of cracks and fractures in the strength reduction region.

[0117] By the way, among the spaces of a predetermined shape forming the non-press-fitting portion described above, in the space opened to the outside, it also has the function of storing foreign matters contained in the fluid, thereby suppressing the occurrence of a phenomenon in which foreign matters are bitten into the seal portion when the valve body rotates.

[0118] In the above-described embodiments, an embodiment in which a non-press-fitting portion is formed on the drive shaft or the press-fitting fixing hole has been shown, but it is also possible to form non-press-fitting portions on both the drive shaft and the press-fitting fixing hole. In this case, any one of the first to sixth embodiments may be combined with any one of the seventh to ninth embodiments.

[0119] As described above, according to the present invention, there is provided a valve body that changes the communication state of a flow path through which a liquid flows, the valve body being formed of a synthetic resin and including a valve body main body having a metal press-fitting fixing cylinder inside, and a drive shaft press-fitted and fixed to the press-fitting fixing cylinder of the valve body main body, wherein a non-press-fitting portion due to a gap is formed in either one or both of the press-fitting fixing cylinder and the drive shaft in the radial direction with respect to the axis of the drive shaft.

[0120] According to this, it is possible to provide a valve body that suppresses the occurrence of cracks and fissures in the synthetic resin forming the valve body main body near the press-fitting fixing cylinder into which the drive shaft is press-fitted, and a flow path switching valve using the same.

[0121] Note that the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, or replace other configurations for a part of the configuration of each embodiment.

Explanation of Reference Numerals

[0122] 10... Flow path switching valve, 11... Housing body, 12A, 12B, 12C, 12D... Connection pipes, 13... Thermostat, 14... Valve body, 15... Electric motor, 16... Motor housing part, 17... Cover, 18... Sealing member, 19... Compression spring, 20... Outer peripheral part, 21... Opening, 22... Closing wall, 23... Drive shaft, 24... Worm wheel, 25... Worm, 26... Worm wheel, 27... Worm, 28... Valve housing part, 29... Communication path, 30... Internal passage, 31... Open part, 32... Fixed part, 33... Flat area part, 34... Inclined area part, 35Mi... First regulating wall, 35Mx... Second regulating wall, 36... Side wall, 37... End face wall, 38... Bearing fixing part, 39Mi... First regulating piece, 39Mx... Second regulating piece, 40... Slide bearing, 41... Press-fitting fixing cylinder, 41H... Press-fitting hole, 47... Non-press-fitting part, 48... Small diameter part, 50... Taper part, 52... Small diameter part, 53... Press-fitting part, 49, 51, 54, 60, 62, 64, 65, 68... Non-press-fitting parts.

Claims

1. A valve element that changes the communication state of a flow path through which a liquid flows, a valve body made of synthetic resin, having one end closed by a closing wall and the other end open by an opening, and having a bottomed cylindrical shape extending in an axial direction, the one end of which is closed by a closing wall and the other end open by an opening, the outer periphery of which is formed with an opening through which a fluid flows out, the closing wall having a circular drive shaft fixing part formed near the center thereof with a tip end surface protruding into the inside of the outer periphery, the drive shaft fixing part having a metal press-fitted fixing cylinder inside, and the metal drive shaft press-fitted and fixed into a press-fit hole of the press-fitted fixing cylinder from the side opposite to the tip end surface of the drive shaft fixing part, the press-fitted fixed cylinder is insert-molded into the drive shaft fixing portion to be integrated therewith, and a gate through which the synthetic resin is injected during the insert molding is provided on the opposite side of the tip end surface of the drive shaft fixing portion, a press-fitting region where the drive shaft is press-fitted into the press-fitting hole of the press-fitting fixed cylinder is formed inside the drive shaft fixing portion on the opposite side to the tip end surface, A non-press-fit portion consisting of a space of a predetermined shape is formed inside the tip end surface side of the drive shaft fixing portion in either the press-fit fixed cylinder or the drive shaft, or in both. A valve body characterized by:

2. A valve body as described in claim 1, The drive shaft is made of stainless steel that does not contain zinc. A valve body characterized by:

3. A valve body as described in claim 1, The drive shaft is press-fitted partway into the press-fit hole of the press-fit fixed barrel, and the space serving as the non-press-fit portion is formed between the tip of the drive shaft and the press-fit hole of the press-fit fixed barrel. A valve body characterized by:

4. A valve body as described in claim 1, the drive shaft includes the press-fit region that is press-fitted into the press-fit hole of the press-fit fixed barrel, and a small diameter portion that has a diameter smaller than that of the press-fit region, The annular space serving as the non-press-fit portion is formed between the small diameter portion of the drive shaft and the press-fit hole of the press-fit fixed barrel. A valve body characterized by:

5. A valve body as described in claim 1, the drive shaft includes a press-fit region that is press-fitted into the press-fit hole of the press-fit fixed cylinder, and a tapered portion whose diameter gradually decreases from the press-fit region toward a tip end of the drive shaft, The annular space serving as the non-press-fit portion is formed between the tapered portion of the drive shaft and the press-fit hole of the press-fit fixed barrel. A valve body characterized by:

6. A valve body as described in claim 1, Inside the drive shaft on the tip side of the drive shaft, a space serving as the non-press-fitting portion is formed along the axis of the drive shaft. A valve body characterized by this.

7. A valve body according to claim 1, wherein Inside the tip surface side of the drive shaft fixing portion, in the press-fitting hole of the press-fitting fixing cylinder, a non-press-fitting portion formed of an annular space surrounding the drive shaft is formed. A valve body characterized by this.

8. A valve body according to any one of claims 1 to 7, wherein The non-press-fitting portion is a space inside the tip surface side of the drive shaft fixing portion that allows deformation of the press-fitting fixing cylinder due to press-fitting of the drive shaft into the press-fitting hole. A valve body characterized by this.

9. A valve body according to any one of claims 1 to 8, and a valve housing including a cylindrical side wall having one end closed by an end face wall facing the closing wall of the valve body and the other end being an open end, and a valve housing including a valve housing portion in which the valve body is rotatably housed around the axis of the valve body, and a communication passage that is opened in the valve housing portion and connected to external auxiliary machines. Near the center of the end face wall of the housing, a bearing fixing portion is formed that extends axially toward the inside of the valve housing portion and faces the drive shaft fixing portion. A flow path switching valve characterized by this.

10. An automotive heat medium system including a fluid pump that pressurizes and pumps a fluid serving as a heat medium for cooling a heat source, and a flow path switching valve that sends the fluid from the fluid pump to a plurality of auxiliary machines, or a flow path switching valve that sends the fluid from the plurality of auxiliary machines to the fluid pump. An automotive heat medium system characterized by using the flow path switching valve according to claim 9 as the flow path switching valve.

11. In the automotive heat medium system according to claim 10, The heat source is an internal combustion engine, and the auxiliary machines are at least a radiator, a heating device, and an oil cooler. The flow path switching valve selectively distributes the cooling water of the internal combustion engine to the radiator, the heating device, and the oil cooler. An automotive heat medium system characterized by this.

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