Fixing structure, throttle valve control device, and method of assembling the throttle valve control device

Abstract

The purpose of the present invention is to provide an affixing structure with which it is possible to inhibit inclination of a tapping screw and stabilize the tapping screw position. Provided is an affixing structure for affixing a screw member 30, 31 to a screw affixing part 35, 36, wherein: the screw member 30, 31 is a tapping screw having a male screw part; the screw affixing part 35, 36 comprises a first female screw part 35GS, 36GS provided to the side on which the screw member 30, 31 enters and a second female screw part 35TS, 36TS provided to the side opposite from the side on which the screw member 30, 31 enters relative to the first female screw part 35GS, 36GS; and the first female screw part 35GS, 36GS has a complete thread of at least 1.5 threads.

Description

[Technical Field]

[0001] The present invention relates to a throttle valve control device, a fixing structure suitable for use in a throttle valve control device, and an assembly method for a throttle valve control device. [Background technology]

[0002] Patent Document 1 describes an invention for a boss for a self-tapping screw. The boss for a self-tapping screw in Patent Document 1 has a pilot hole formed therein into which the self-tapping screw is screwed, and a spiral inclined surface formed around the opening of the pilot hole (see paragraph 0023). The inclined surface is formed so as to extend radially from the inner wall surface of the pilot hole (see paragraph 0024). The inclination angle θ1 of the inclined surface is approximately the same as the lead angle θ2 of the self-tapping screw, and the circumferential distance from the start point to the end point of the inclined surface is the distance of approximately one revolution around the inner wall surface of the pilot hole, so that the side of the thread is stably supported by the inclined surface over the entire circumference (see paragraph 0040). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-36310 Summary of the Invention [Problem to be solved by the invention]

[0004] In the boss for the self-tapping screw in Patent Document 1, the circumferential distance from the start point to the end point of the inclined surface is only the distance of approximately one revolution around the inner wall surface of the pilot hole, and the inclined surface only supports the self-tapping screw by abutting against one side of the thread, so sufficient consideration has not been given to preventing the self-tapping screw from tipping over. Hereinafter, self-tapping screws will be referred to as tapping screws.

[0005] An object of the present invention is to provide a fixing structure that can suppress tilting of a tapping screw and stabilize the attitude of the tapping screw. [Means for solving the problem]

[0006] In order to achieve the above object, the fixing structure of the present invention comprises: A fixing structure for fixing a screw member to a screw fixing portion, the screw member is a tapping screw having a male thread portion, The screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on the opposite side of the inlet side with respect to the first female thread portion, The first female thread portion is The tapping screw is formed before being screwed in. At least 1.5 full threads death, The second female threaded portion holds the tapping screw by surface pressure generated by elastic deformation of the threads formed by screwing the tapping screw. do. The fixing structure of the present invention is A fixing structure for fixing a screw member to a screw fixing portion, the screw member is a tapping screw having a male thread portion, The screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on the opposite side of the inlet side with respect to the first female thread portion, the first female threaded portion has at least 1.5 full threads; The screw fixing portion has a tapered portion closer to the inlet than the first female thread portion and having the same taper angle as the tapered portion formed at the tip end of the screw member.

[0007] In order to achieve the above object, the throttle valve control device of the present invention comprises: The throttle valve includes a screw member that restricts the opening of the throttle valve to a predetermined angle, and a screw fixing portion that fixes the screw member, the screw member is a tapping screw having a male thread portion, The screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on the opposite side of the inlet side with respect to the first female thread portion, The first female thread portion and the second female thread portion are formed such that the height of the thread of the first female thread portion is lower than the height of the thread of the second female thread portion, The first female thread portion is The tapping screw is formed before being screwed in. At least 1.5 full threads death, The second female threaded portion holds the tapping screw by surface pressure generated by elastic deformation of the threads formed by screwing the tapping screw. do.

[0008] In order to achieve the above object, the method for assembling a throttle valve control device of the present invention comprises the steps of: a throttle valve fixed to the throttle shaft; an intake passage in which the throttle valve is disposed; a throttle body having the intake passage; a throttle gear fixed to the throttle shaft; a default lever configured coaxially with the throttle gear; a full-close screw for determining a full-close position of the throttle valve; a default screw for determining a default position of the throttle valve; a fully closed screw fixing portion to which the fully closed screw is fixed; a default screw fixing portion to which the default screw is fixed, a method for assembling a throttle valve control device, in which the fully-closed screw fixing portion and the default screw fixing portion are provided on the throttle body, A tapping screw is used for at least one of the fully closed screw and the default screw, Of the fully closed screw fixing portion and the default screw fixing portion, a screw fixing portion using the tapping screw is provided with a pilot hole having a diameter smaller than the outer diameter of the tapping screw, and a first female screw portion disposed on the inlet side of the tapping screw and having at least 1.5 full threads, The tapping screw is threaded into the prepared hole through the first female thread portion, and a second female thread portion is formed on the opposite side of the first female thread portion from the inlet side. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a fixing structure that can suppress tilting of a tapping screw and stabilize the attitude of the tapping screw. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 10 is a cross-sectional view of a tapping screw before being tightened. [Figure 2] FIG. 10 is a cross-sectional view of the tapping screw after it has been tightened. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a main part of a fastening portion of a tapping screw. [Figure 4] 1 is a cross-sectional view of a throttle valve control device used in a gasoline engine vehicle. [Figure 5] FIG. 2 is a perspective view of a gear cover of a throttle valve control device used in a gasoline engine vehicle. [Figure 6] 1 is a perspective view of the appearance of a throttle valve control device used in a gasoline engine vehicle. [Figure 7] FIG. 2 is a plan view of a gear storage chamber of a throttle valve control device used in a gasoline engine vehicle. [Figure 8] 1 is an exploded perspective view of a throttle valve control device used in a gasoline engine vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An embodiment of a fixing structure using a tapping screw will be described with reference to FIGS.

[0012] FIG. 1 is a cross-sectional view of tapping screws 30 and 31 before they are tightened. The fixing structure according to the present invention is configured in the fixing portion (fastening portion) of the adjusting screw. The fixing portion of the adjusting screw is used in a motor-driven throttle-type throttle valve control device (hereinafter referred to as a throttle valve control device) for a gasoline engine, but the fixing structure (fastening structure) of the present invention can be applied to fixing portions that use tapping screws other than the fixing portion of the adjusting screw.

[0013] In the throttle valve control device employed in this embodiment, the fully closed opening degree and default opening degree of the throttle valve are adjusted using a fully closed stopper 30 and a default stopper 31. Screws (adjustment screws) are used for the fully closed stopper 30 and the default stopper 31. The screw that constitutes the fully closed stopper 30 is called the "fully closed screw," and the screw that constitutes the default stopper 31 is called the "default screw."

[0014] The base member 37 is provided with a fully-closing screw fixing portion 35 to which the fully-closing screw 30 is fastened, and a default screw fixing portion 36 to which the default screw 31 is fastened. The fully-closing screw 30 and the default screw 31 are fastened to the fully-closing screw fixing portion (fully-closing screw fastening portion) 35 and the default screw fixing portion (default screw fastening portion) 36, and the positions of the fully-closing screw tip portion 30H and the default screw tip portion 31H are adjusted by adjusting the feed amount of the screws at this time.

[0015] Here, self-tapping type screws (tapping screws) are used for the fully closed screw 30 and the default screw 31. There are various types of tapping screws, but when using them in a location where a drive unit is located nearby, such as inside the gearbox of a throttle valve control device, it is desirable to use a type of tapping screw that does not produce chips. Among these types of tapping screws, there are those with triangular threads that reduce tightening torque and make plastic processing easier, and whose thread pitch is the same as that of a normal machine screw. Using such tapping screws can improve the workability of the throttle valve control device assembly work.

[0016] The pilot hole 35H provided in the fully closed screw fixing portion 35 has a fully closed screw pilot hole thread forming portion 35D1, a fully closed screw pilot hole entrance-side parallel portion 35D2, a fully closed screw pilot hole tapered portion 35T, and a fully closed screw pilot hole guide screw portion (first female thread portion) 35GS. The fully closed screw pilot hole thread forming portion 35D1 is the portion where the tapping screw forms its threads, and the holding force of the tapping screw can be ensured by the surface pressure generated by the elastic deformation remaining in the base member even after thread formation. The fully closed screw pilot hole guide screw portion 35GS is provided in the pilot hole 35H on the side that will be the entrance of the fully closed screw 30.

[0017] When the thread roots are formed in the base member 37, the material that was in the roots flows to the thread crests. For this reason, it is important to set the diameter of the pilot hole 35H (hereinafter referred to as the pilot hole diameter) to an appropriate size. To ensure the holding force of the tapping screw after fastening while preventing excessive tightening torque, it is desirable to set the pilot hole diameter to a diameter approximately halfway between the crest diameter and the root diameter of the tapping screw.

[0018] At the entrance of the pilot hole 35H, there are provided a fully closed screw pilot hole entrance-side parallel portion 35D2, a fully closed screw pilot hole tapered portion 35T, and a fully closed screw pilot hole guide screw portion 35GS in order to stabilize the posture of the tapping screw before tightening. The fully closed screw pilot hole entrance-side parallel portion 35D2 has a diameter φ35D2 that is slightly larger than the outer diameter φ30 of the fully closed screw 30, which contributes to stabilizing the posture of the fully closed screw 30.

[0019] Furthermore, when the tip of the totally closing screw 30 is inserted into the prepared hole 35H, the tapered portion 35T of the totally closing screw pilot hole guides the totally closing screw 30 so that the axis of the prepared hole 35H coincides with the axis of the totally closing screw 30. For this reason, a tapered portion 30T is formed at the tip of the totally closing screw 30, and the tapered portion 35T of the totally closing screw pilot hole and the tapered portion 30T of the totally closing screw 30 are formed at the same taper angle.

[0020] Furthermore, the thread pitch P35GS of the fully closed screw pilot hole guide screw portion 35GS and the thread pitch P30 of the fully closed screw 30 are the same pitch, which firmly stabilizes the posture of the fully closed screw 30 when it is tightened.

[0021] Here, the fully-closing screw pilot hole guide screw portion 35GS preferably has 1.5 or more complete threads to stabilize the tightening posture of the fully-closing screw 30. Here, the more threads there are, the more stable the posture of the fully-closing screw 30 becomes, but increasing the length of the fully-closing screw pilot hole guide screw portion 35GS may result in the fully-closing screw fixing portion 35 becoming larger, or shortening the length of the fully-closing screw pilot hole thread forming portion 35D1 may reduce the holding power of the fully-closing screw 30. For this reason, it is desirable to keep the fully-closing screw pilot hole guide screw portion 35GS to the minimum necessary length. Specifically, it is preferable that the fully-closing screw pilot hole guide screw portion 35GS have approximately 1.5 to 2 complete threads formed.

[0022] In this embodiment, a complete thread of more than 1.5 threads is formed in the fully closed screw pilot hole guide screw portion 35GS, so that when the fully closed screw 30 is inserted into the pilot hole 35H, the threads of the fully closed screw 30 fit into the valleys of the complete threads of the fully closed screw pilot hole guide screw portion 35GS, and both sides of the threads of the fully closed screw 30 are supported by the complete threads of the fully closed screw pilot hole guide screw portion 35GS. That is, the fully-closing screw pilot hole guide screw portion 35GS is formed to face a portion of the thread of the male thread portion of the fully-closing screw 30 from both sides of the thread. Therefore, the posture of the fully-closing screw 30 can be stabilized before the thread of the fully-closing screw 30 reaches the fully-closing screw pilot hole thread forming portion 35D1.

[0023] In addition, the fully closed screw pilot hole guide screw portion 35GS also has incomplete thread portions GSa and GSb formed before and after the complete thread portion, and the incomplete thread portion GSb formed before the complete thread portion also contributes to stabilizing the posture of the fully closed screw 30. Here, in order to machine the pilot hole 35H with a shape that combines such various portions, it is desirable to use an integrated cutting tool that can machine each portion simultaneously at once. This is because machining with an integrated cutting tool can prevent axial misalignment of each portion.

[0024] Next, the default screw 31 and the default screw fixing portion 36 will be described. The pilot hole 36H provided in the default screw fixing portion 36 has a default pilot hole thread forming portion 36D1, a default pilot hole entrance parallel portion 36D2, a default pilot hole tapered portion 36T, and a default pilot hole guide screw portion 36GS. The default pilot hole thread forming portion 36D1 is the portion where the tapping screw forms its threads, and the holding force of the tapping screw is ensured by the surface pressure generated by the elastic deformation remaining in the base member even after thread formation. The default pilot hole guide screw portion 36GS is provided in the pilot hole 36H on the side that will be the entrance of the default screw 31.

[0025] Here, it is important to set the diameter of the pilot hole 36H (hereinafter referred to as pilot hole diameter) to an appropriate size because the material that was in the roots of the threads flows to the crests when the roots of the threads are formed in the base member 37. To ensure the holding power of the tapping screw after fastening while preventing excessive tightening torque, it is desirable to set the pilot hole diameter to a diameter approximately halfway between the crest diameter and the root diameter of the tapping screw.

[0026] At the entrance of the pilot hole 36H, there are provided a default pilot hole entrance parallel portion 36D2, a default pilot hole tapered portion 36T, and a default pilot hole guide screw portion 36GS to stabilize the posture of the tapping screw before it is tightened. The default pilot hole entrance parallel portion 36D2 has a diameter φ36D2 that is slightly larger than the outer diameter φ31 of the default screw 31, which contributes to stabilizing the posture of the default screw 31.

[0027] Furthermore, when the tip of the default screw 31 is inserted into the pilot hole 36H, the default screw pilot hole tapered portion 36T guides the default screw 31 so that the axis of the pilot hole 36H coincides with the axis of the default screw 31. For this reason, a tapered portion 31T is formed at the tip of the default screw 31, and the default screw pilot hole tapered portion 36T and the tapered portion 31T of the default screw 31 are formed at the same taper angle.

[0028] Furthermore, the thread pitch P36GS of the default screw pilot hole guide thread portion 36GS and the thread pitch P31 of the default screw 31 are the same pitch, which firmly stabilizes the posture of the default screw 31 when it is tightened.

[0029] Here, the default pilot hole guide screw portion 36GS preferably has 1.5 or more complete threads to stabilize the tightening posture of the default screw 31. Here, the more threads there are, the more stable the posture of the default screw 31. However, increasing the length of the default pilot hole guide screw portion 36GS may result in a larger default screw fixing portion 36, or shortening the length of the default pilot hole thread forming portion 36D1 may reduce the holding power of the default screw 31. For this reason, it is desirable to keep the default pilot hole guide screw portion 36GS to the minimum necessary length. Specifically, it is preferable that the default pilot hole guide screw portion 36GS have approximately 1.5 to 2 complete threads formed.

[0030] In this embodiment, the default pilot hole guide thread portion 36GS is formed with more than 1.5 full threads. Therefore, when the default screw 31 is inserted into the pilot hole 36H, the threads of the default screw 31 fit into the roots of the full threads of the default pilot hole guide thread portion 36GS, and both side surfaces of the threads of the default screw 31 are supported by the full threads of the default pilot hole guide thread portion 36GS. In other words, the default pilot hole guide thread portion 36GS is formed to face a portion of the threads of the male thread portion of the default screw 31 from both side surfaces of the threads. Therefore, the posture of the default screw 31 can be stabilized before the threads of the default screw 31 reach the default pilot hole thread forming portion 36D1.

[0031] Additionally, the default screw pilot hole guide thread portion 36GS also has incomplete thread portions GSa and GSb formed before and after the complete thread portion, but the incomplete thread portion GSb formed before the complete thread portion also contributes to stabilizing the posture of the default screw 31. Here, in order to machine the pilot hole 36H with a shape that combines each of these portions, it is desirable to use an integrated cutting tool that can machine each portion simultaneously at once. This is because machining with an integrated cutting tool can prevent axial misalignment of each portion.

[0032] Fig. 2 is a cross-sectional view of the tapping screws 30 and 31 after they have been tightened. Fig. 3 is an enlarged cross-sectional view of the main part of the tightening portion of the tapping screw 30. When the totally closed screw 30 is tightened into the pilot hole 35H of the totally closed screw fixing portion 35, the cross section of the totally closed screw 30 has a triangular shape, so a totally closed screw gap 35C, which is a partial gap, is formed between the totally closed screw formed female thread portion (second female thread portion) 35TS formed by tightening the totally closed screw 30 and the totally closed screw 30. Here, on the totally closed screw gap 35C side, a totally closed screw thread portion small diameter portion 30S1 where the outer diameter of the triangular totally closed screw 30 is small is arranged, and on the side without the gap, a totally closed screw portion large diameter portion 30S21 where the outer diameter is large is arranged.

[0033] Furthermore, the fully closed screw forming female thread portion 35TS formed by tightening the fully closed screw 30 has a complete thread, but the fully closed screw pilot hole guide screw portion 35GS, which has a thread cut in advance, does not have a complete thread because its tip diameter is only up to the pilot hole diameter. Here, even if the pilot hole diameter is large and the fully closed screw forming female thread portion 35TS does not have a complete thread, the thread height of the fully closed screw pilot hole guide screw portion 35GS will be lower than the thread height of the fully closed screw forming female thread portion 35TS.

[0034] The fully closed screw forming female thread portion 35TS is provided on the opposite side of the fully closed screw 30 from the inlet side with respect to the fully closed screw prepared hole guide thread portion 35GS.

[0035] On the other hand, when the default screw 31 is tightened into the pilot hole 36H of the default screw fixing portion 36, the cross section of the default screw 31 has a triangular shape, and therefore a default screw gap portion 36C, which is a partial gap, is formed between the default screw forming female thread portion 36TS formed by tightening the default screw 31 and the default screw 31. Here, on the default screw gap portion 36C side, a default screw portion small diameter portion 31S1 is arranged, which has a triangular cross section and a small outer diameter of the default screw 31, and on the side where there is no gap, a default screw portion large diameter portion 31S2 is arranged, which has a larger outer diameter.

[0036] Furthermore, the default thread forming female thread portion 36TS formed by tightening the default screw 31 has a complete thread, but the default screw pilot hole guide screw portion 36GS, which has a pre-threaded thread, does not have a complete thread because its tip diameter is only as large as the pilot hole diameter. Here, even if the pilot hole diameter is large and the default thread forming female thread portion 36TS does not have a complete thread, the thread height of the fully closed screw pilot hole guide screw portion 35GS will be lower than the thread height of the fully closed screw forming female thread portion 35TS.

[0037] The default thread forming female thread portion 36TS is provided on the opposite side of the default screw hole guide thread portion 36GS from the inlet side of the default screw 31.

[0038] This fixing structure of the fully closed screw 30 and the default screw 31 adjustably regulates the positions of the fully closed screw tip 30H and the default screw tip 31H that abut against the fully closed stopper member 12 and the default stopper member 33.

[0039] As described above, when the fully closed screw 30 and the default screw 31 form the thread roots, the material that was in the roots flows to the thread crests. As a result, the thread heights of the fully closed screw pilot hole guide screw portion 35GS and the default screw pilot hole guide screw portion 36GS are lower than the thread heights of the fully closed screw-forming female thread portion 35TS and the default screw-forming female thread portion 36TS. In Figure 3, the difference between the thread height of the fully closed screw pilot hole guide screw portion 35GS and the thread height of the fully closed screw-forming female thread portion 35TS is shown as δ35, and the difference between the thread height of the default screw pilot hole guide screw portion 36GS and the thread height of the default screw-forming female thread portion 36TS is shown as δ36.

[0040] For this reason, the fully-closing screw fixing portion 35 has two types of female thread portions 35GS, 35TS of different heights, and the default screw fixing portion 36 has two types of female thread portions 36GS, 36TS of different heights. The fully-closing screw fixing portion 35 has a first female thread portion 35GS with a low height arranged on the inlet side of the fully-closing screw 30, and a second female thread portion 35TS with a high height arranged on the outlet side of the fully-closing screw 30. Furthermore, the default fixing portion 36 has a first female thread portion 36GS with a low height arranged on the inlet side of the default screw 31, and a second female thread portion 36TS with a high height arranged on the outlet side of the default screw 31.

[0041] Next, an example in which the fixing structure of this embodiment is applied to a throttle valve control device for a gasoline engine will be specifically described with reference to FIGS.

[0042] In conventional throttle valve control devices, adjustment of the two opening degrees, fully closed and default, was performed by adjusting the angle of the stopper by adjusting the drive-in amount of the adjustment screw. This adjustment involved tightening the nut after adjusting the adjustment screw, which resulted in the problem of slight deviations in the opening degree when the nut was tightened. Furthermore, when a self-tapping screw was used to solve this problem and elimination of nut tightening was implemented, the posture of the self-tapping screw when tightened became unstable, making it prone to tilted tightening. When tilted tightening of the self-tapping screw occurs, it becomes impossible to tighten the self-tapping screw (tapping screw) and the accuracy of the opening degree adjustment decreases.

[0043] By adopting the fixing structure of this embodiment, the posture of the tapping screw is stabilized at the beginning of tightening, which makes it possible to improve the positional accuracy of the screw tip and reduce the variation in tightening torque. This allows for highly accurate tightening control of the tapping screw and improves the angular accuracy of the stopper. As a result, the flow rate accuracy of the throttle valve control device can be improved.

[0044] Fig. 4 is a cross-sectional view of a throttle valve control device used in a gasoline engine vehicle. Fig. 5 is a perspective view of a gear cover 24 of a throttle valve control device used in a gasoline engine vehicle. Fig. 6 is a perspective view of the exterior of a throttle valve control device used in a gasoline engine vehicle. Fig. 7 is a plan view of a gear storage chamber 40 of a throttle valve control device used in a gasoline engine vehicle. Fig. 8 is an exploded perspective view of a throttle valve control device used in a gasoline engine vehicle.

[0045] The configuration of the motor-driven throttle valve control device will now be described. As shown in FIG. 1, an intake passage 1 (hereinafter referred to as a bore) and a motor housing 20A that accommodates a motor 20 are integrally molded in an aluminum die-cast throttle valve assembly (hereinafter referred to as a throttle body) 6.

[0046] A metal throttle shaft 3 is disposed in the throttle body 6 along the diameter line of the bore 1. The gear-side end of the throttle shaft 3 is rotatably supported by a needle bearing 9, and the opposite-gear-side end is rotatably supported by a ball bearing 10. The needle bearing 9 and ball bearing 10 are press-fitted and fixed into bearing bosses 7 and 8 provided on the throttle body 6. In this way, the throttle shaft 3 is rotatably supported relative to the throttle body 6.

[0047] A slit is provided in the throttle shaft 3, and a throttle valve (hereinafter referred to as the throttle valve) 2, which is a metal disk, is inserted into the slit and fixed to the throttle shaft 3 with screws 4 and 5. Thus, when the throttle shaft 3 rotates, the throttle valve 2 rotates, which in turn changes the cross-sectional area of ​​the intake passage and controls the intake air flow rate to the engine.

[0048] The motor housing 20A is formed substantially parallel to the throttle shaft 3, and the brush type DC motor 20 is housed in the motor housing 20A. The motor 20 is fixed by fastening a screw 18 (see FIG. 8) into a hole 20C (see FIG. 8) in a bracket 20B (see FIG. 8). A wave washer 19 is installed at the end of the motor 20, and the wave washer 19 holds the motor 20 in place.

[0049] The openings of the bearing bosses 7, 8 are sealed with needle bearings 9 and ball bearings 10, which form a shaft seal and are configured to maintain airtightness. The end on the bearing boss 8 side is sealed with a cap 11, which prevents the end of the throttle shaft 3 and the ball bearing 10 from being exposed. This prevents air from leaking from the bearings or lubricating oil from the bearings from leaking into the outside air or into the sensor chamber, which will be described later.

[0050] A throttle gear 12 is fixed to the end of the throttle shaft 3 on the gear cover 24 side. The throttle gear 12 is made up of a metal plate 13 and a resin gear portion 14 that is resin-molded onto the metal plate 13.

[0051] The metal plate 13 is press-fitted onto the throttle shaft 3 through a hole provided in the center. A nut 15 is screwed onto the metal plate 13 to secure it to the throttle shaft 3. The tip of the throttle shaft 3 not only functions as a press-fit portion, but also as a nut guide portion, guiding the nut 15 to the screw-fit portion. Thus, the metal plate 13 and the resin gear portion 14 molded onto it rotate integrally with the throttle shaft 3.

[0052] The bore side of the throttle gear 12 is held in place by a return spring 32 formed by a helical spring and a default spring 34. A default lever 33 is disposed between these two types of springs.

[0053] One side of the return spring 32 wraps around the bearing boss 7, and its tip is held in a notch formed in the throttle body 6. The other end is held in a hook portion provided on the bearing boss 7 side of the default lever 33. A default spring 34 is held in the throttle gear side hook portion of the default lever 33, and the other end of the default spring 34 is held in the hook portion of the throttle gear 12.

[0054] In addition, a default screw 31 (see Figure 8) is fixed to the side wall of the throttle body 6, and the initial position of the default lever 33 is mechanically set by the default screw 31 coming into contact with the end of the default lever 33.

[0055] An intermediate gear 23 is rotatably inserted into a metal gear shaft 21 that is press-fitted into the throttle body 6 and meshes between a gear 22 attached to the rotating shaft of the motor 20 and a gear 12 fixed to the throttle shaft 3. The intermediate gear 23 is made up of a large-diameter gear 23A that meshes with the gear 22 and a small-diameter gear 23B that meshes with the throttle gear 12. Both gears 23A and 23B are molded integrally by resin molding. These gears 22, 23A, 23B, and 12 constitute a reduction gear mechanism.

[0056] Thus, the rotation of the motor 20 is transmitted to the throttle shaft 3 via this reduction gear mechanism.

[0057] These reduction gear mechanisms and spring mechanisms are covered by a resin gear cover 24. A groove is formed around the periphery of the open end of the gear cover 24, and when the gear cover 24, with a seal member 28 attached to this groove, is placed over the throttle body 6, the seal member 28 comes into close contact with the end face of a frame formed on the side of the throttle body 6 around the gear storage chamber 40, sealing off the inside of the gear storage chamber 40 from the outside air. In this state, the gear cover 24 is fixed to the throttle body 6 with six clips 25.

[0058] Here, after the throttle shaft 3 is assembled to the throttle body 6, the height of the excitation conductor 16 can be adjusted by press-fitting the resin rotor 17 into the throttle shaft 3. This allows the clearances between the excitation conductor 16 and the excitation conductor 26 and the signal detection conductor 27 to be adjusted with high precision, making it possible to obtain a highly accurate non-contact rotation angle detection device.

[0059] As shown in Figure 7, 6A, 6B, and 6C are walls for positioning the gear cover 24 (see Figure 5). By placing the gear cover 24 over the throttle body 6 so that these three walls align with the protrusions 24A, 24B, and 24C (see Figure 5) of the gear cover 24, the excitation conductor 26 (see Figure 1) and the signal detection conductor 27 (see Figure 1) are positioned opposite the rotating side conductors.

[0060] The full-open stopper 29 mechanically determines the full-open position of the throttle gear 12, and is composed of a protrusion formed integrally with the side wall of the throttle body 6. When the notched end of the throttle gear 12 comes into contact with this protrusion 29, the throttle shaft 3 cannot rotate beyond the full-open position. This determines the maximum value of the rotational position of the fixed-side conductor (excitation conductor 16) fixed to the end of the throttle shaft 3.

[0061] 8, a full-closing screw 30 is fixed (fastened) to the full-closing screw fixing portion 35, and the end of the throttle gear 12 comes into contact with the full-closing screw 30 at the full-closed position. In other words, the full-closed position of the throttle gear 12 is mechanically determined by the full-closing screw 30. When the throttle gear 12 is in contact with the full-open stopper 29 (see FIG. 7) and the full-close screw 30, the output of the signal detection conductor becomes a full-open value and a full-close value.

[0062] Additionally, a default screw 31 is fixed (fastened) to the default screw fixing portion 36, and an end of a default lever 33 configured coaxially with the throttle gear 12 comes into contact with the default screw 31 at the default position. In other words, the default position of the default lever 33 is mechanically determined by the default screw 31. Here, since the default screw 31 is assembled from the outside of the gearbox, a pre-coated adhesive is applied to the threaded portion, and as the adhesive begins to harden when tightened, it hardens, thereby ensuring airtightness inside the gearbox.

[0063] The above-described embodiment has been described as a motor-driven throttle valve control device (motor-driven throttle valve control device) for a gasoline engine vehicle equipped with an inductive non-contact rotation detection device, but the present invention can also be applied to a motor-driven throttle valve control device for a diesel engine vehicle. The present invention can also be applied to a sensor that detects the rotation angle of an accelerator as a rotation angle detection sensor. The present invention can also be applied to a rotation angle detection device for an actuator that controls movable vanes in a turbocharger. The present invention can also be applied to a rotation angle detection device for a gear shift actuator in an automatic transmission. The present invention can also be applied to a rotation angle detection device for a 2WD / 4WD switching actuator.

[0064] The above-described embodiment of the present invention has the following features. Note that the fully-closing screw 30 and the fully-closing screw fixing portion 35 and the default screw 31 and the default screw fixing portion 36 described in the above-described embodiment have similar configurations, and therefore will be described as a "screw member" and a "screw fixing portion" when there is no need to distinguish between them.

[0065] (1) A fixing structure for fixing the screw members 30, 31 to the screw fixing portions 35, 36, The screw members 30 and 31 are tapping screws having male threads, The screw fixing portions 35, 36 include first female thread portions 35GS, 36GS provided on the inlet side of the screw members 30, 31, and second female thread portions 35TS, 36TS provided on the opposite side of the inlet side of the screw members 30, 31 from the first female thread portions 35GS, 36GS, The first female threaded portions 35GS, 36GS have at least 1.5 full threads.

[0066] (2) The first female threaded portions 35GS, 36GS are formed with threads that face both sides of the threads of part of the male threaded portions of the screw members 30, 31.

[0067] (3) The first female threaded portions 35GS, 36GS and the second female threaded portions 35TS, 36TS are formed such that the thread height of the first female threaded portions 35GS, 36GS is lower than the thread height of the second female threaded portions 35TS, 36TS.

[0068] (4) The screw fixing portions 35, 36 are provided with tapered portions 35T, 36T, which are located closer to the entrance of the screw members 30, 31 than the first female thread portions 35GS, 36GS and have the same taper angle as the tapered portions 30T, 31T formed at the tip ends of the screw members 30, 31.

[0069] (5) A throttle valve control device, The device comprises a throttle valve (2), screw members (30, 31) that restrict the opening of the throttle valve (2) to a predetermined angle, and screw fixing portions (35, 36) that fix the screw members (30, 31), The screw members 30 and 31 are tapping screws having male threads, The screw fixing portions 35, 36 include first female thread portions 35GS, 36GS provided on the inlet side of the screw members 30, 31, and second female thread portions 35TS, 36TS provided on the opposite side of the inlet side of the screw members 30, 31 from the first female thread portions 35GS, 36GS, The first female threaded portions 35GS, 36GS and the second female threaded portions 35TS, 36TS are formed such that the thread height of the first female threaded portions 35GS, 36GS is lower than the thread height of the second female threaded portions 35TS, 36TS, The first female threaded portions 35GS, 36GS have at least 1.5 full threads.

[0070] (6) an intake passage 1 in which a throttle valve 2 fixed to a throttle shaft 3 is disposed; a throttle body 6 having an intake passage 1; a throttle gear 12 fixed to the throttle shaft 3; a default lever 33 configured coaxially with the throttle gear 12; The screw fixing portions 35, 36 are provided on the throttle body 6, The screw members 30, 31 include a full-close screw 30 that determines the full-close position of the throttle valve 2 and a default screw 31 that determines the default position of the throttle valve 2, The screw fixing portions 35, 36 include a fully closing screw fixing portion 35 to which the fully closing screw 30 is fixed and a default screw fixing portion 36 to which the default screw 31 is fixed.

[0071] (7) a throttle valve 2 fixed to a throttle shaft 3; an intake passage 1 in which a throttle valve 3 is disposed; a throttle body 6 having an intake passage 1; a throttle gear 12 fixed to the throttle shaft 3; A default lever 33 configured coaxially with the throttle gear 12; a full-close screw 30 for determining the full-close position of the throttle valve 3; A default screw 31 that determines the default position of the throttle valve 3; a fully closed screw fixing portion 35 to which the fully closed screw 30 is fixed; a default screw fixing portion 36 to which the default screw 31 is fixed; The fully closed screw fixing portion 35 and the default screw fixing portion 36 are used in an assembly method of a throttle valve control device provided in the throttle body 6, A tapping screw is used for at least one of the fully closed screw 30 and the default screw 31, Of the fully closed screw fixing portion 35 and the default screw fixing portion 36, the screw fixing portion using a tapping screw is provided with a pilot hole 35H, 36H having a diameter smaller than the outer diameter of the tapping screw, and a first female screw portion 35GS, 36GS arranged on the inlet side of the tapping screw and having at least 1.5 full threads, Tapping screws are threaded into the prepared holes 35H, 36H through the first female thread portions 35GS, 36GS, and second female thread portions 35TS, 36TS are formed on the side opposite to the inlet side of the tapping screws relative to the first female thread portions 35GS, 36GS.

[0072] (8) The first female thread portions 35GS, 36GS and the second female thread portions 35TS, 36TS are formed such that the height of the threads of the first female thread portions 35GS, 36GS is lower than the height of the threads of the second female thread portions 35TS, 36TS.

[0073] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations. Furthermore, it is possible to add, delete, or replace part of the configuration of the embodiments with other configurations. [Explanation of symbols]

[0074] 1...intake passage, 2...throttle valve, 3...throttle shaft, 6...throttle body, 12...throttle gear, 30...threaded member (fully closed thread), 30T...tapered portion of fully closed thread 30, 31...threaded member (default thread), 31T...tapered portion of default thread 31, 33...default lever, 35...screw fixing portion (fully closed thread fixing portion), 35GS...first female threaded portion (fully closed thread pilot hole guide screw portion), 35H...pilot hole of fully closed thread fixing portion 35, 35TS...second female threaded portion (fully closed thread formed female thread portion), 36...screw fixing portion (default screw fixing portion), 36GS...first female threaded portion (default screw pilot hole guide screw portion 36GS), 36H...pilot hole of default screw fixing portion 35, 36TS...second female threaded portion (default thread formed female thread portion).

Claims

1. A fixing structure for fixing a screw member to a screw fixing portion, the screw member is a tapping screw having a male thread portion, the screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on an opposite side of the inlet side with respect to the first female thread portion, The first female thread portion has at least 1.5 full threads formed before the tapping screw is screwed in, The second female thread portion is a fixing structure that holds the tapping screw by surface pressure generated by elastic deformation of the threads formed by screwing the tapping screw.

2. A fixing structure for fixing a screw member to a screw fixing part, the screw member is a tapping screw having a male thread portion, the screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on an opposite side of the inlet side with respect to the first female thread portion, the first female threaded portion has at least 1.5 full threads; A fixing structure in which the screw fixing portion has a tapered portion on the inlet side of the first female thread portion, the tapered portion having the same taper angle as the tapered portion formed at the tip end of the screw member.

3. The fixing structure according to claim 1 or 2, The first female threaded portion has a fixing structure in which threads are formed so as to face both sides of a portion of the threads of the male threaded portion.

4. The fixing structure according to claim 1 or 2, The first female thread portion and the second female thread portion have a fixing structure in which the height of the threads of the first female thread portion is lower than the height of the threads of the second female thread portion.

5. The throttle valve includes a screw member that restricts the opening of the throttle valve to a predetermined angle, and a screw fixing portion that fixes the screw member, the screw member is a tapping screw having a male thread portion, the screw fixing portion includes a first female thread portion provided on an inlet side of the screw member and a second female thread portion provided on an opposite side of the inlet side with respect to the first female thread portion, The first female thread portion and the second female thread portion are formed such that the height of the thread of the first female thread portion is lower than the height of the thread of the second female thread portion, The first female thread portion has at least 1.5 full threads formed before the tapping screw is screwed in, The second female threaded portion holds the tapping screw by surface pressure generated by elastic deformation of the threads formed by screwing the tapping screw.

6. 6. The throttle valve control device according to claim 5, an intake passage in which the throttle valve fixed to a throttle shaft is disposed; a throttle body having the intake passage; a throttle gear fixed to the throttle shaft; a default lever configured coaxially with the throttle gear, The screw fixing portion is provided on the throttle body, The screw member includes a full-close screw that determines a full-close position of the throttle valve, and a default screw that determines a default position of the throttle valve, The throttle valve control device has, as the screw fixing portion, a full-closing screw fixing portion to which the full-closing screw is fixed, and a default screw fixing portion to which the default screw is fixed.

7. a throttle valve fixed to the throttle shaft; an intake passage in which the throttle valve is disposed; a throttle body having the intake passage; a throttle gear fixed to the throttle shaft; a default lever configured coaxially with the throttle gear; a full-close screw for determining a full-close position of the throttle valve; a default screw for determining a default position of the throttle valve; a fully closed screw fixing portion to which the fully closed screw is fixed; a default screw fixing portion to which the default screw is fixed, a method for assembling a throttle valve control device, in which the fully-closed screw fixing portion and the default screw fixing portion are provided on the throttle body, A tapping screw is used for at least one of the fully closed screw and the default screw, Of the fully closed screw fixing portion and the default screw fixing portion, a screw fixing portion using the tapping screw is provided with a pilot hole having a diameter smaller than the outer diameter of the tapping screw, and a first female screw portion is formed in advance, the first female screw portion being disposed on the inlet side of the tapping screw and having at least 1.5 full threads, A method for assembling a throttle valve control device, comprising threading the tapping screw through the first female thread portion into the prepared hole, and forming a second female thread portion on the opposite side of the first female thread portion from the inlet side.

8. 8. The method for assembling a throttle valve control device according to claim 7, A method for assembling a throttle valve control device, wherein the first female thread portion and the second female thread portion are formed such that the thread height of the first female thread portion is lower than the thread height of the second female thread portion.

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