Throttle valve device

Abstract

Throttle valve device with: a body (300) which defines within itself a passage (320) and an engine compartment (330); a wave (402) which extends in the passage of the body in a direction perpendicular to the passage; a pair of bearings (405, 406) arranged on both sides of the passage of the body, the pair of bearings rotatably supporting the shaft; a valve (400) which rotates together with the shaft to selectively open and close the passage; a motor (100) which is arranged in the engine compartment of the body, wherein the motor rotates in response to an electrical signal; a valve gear (210) which is arranged coaxially with the shaft in the body, wherein the valve gear is connected to the shaft via a lever (401) such that the valve gear transmits a rotation of the motor to the shaft; a coil spring (450) arranged between the valve gear and the valve in the body, the coil spring applying a preload force when the rotation of the motor is transmitted to the shaft; a first guide (460) that covers one side of the coil spring; and a second guide (461) covering the other side of the coil spring; wherein at least one of the first and second leaders has the following: a circular holder (462) which faces an end face (453, 454) of the coil spring; a spring end retaining section (468) which projects outwards from the circular holder and is designed to hold a spring end (451, 452) of the coil spring; a hub (463) rotatably connected to the shaft; and a connecting section (465) that connects the hub and the circular holder, wherein The first guide is in contact with the lever only at one end face of the hub, if at least one of the first guides and the second guide is the first guide, and the second guide with one (406) of the pair of bearings located near the valve gear is in contact at an end face of the hub, if at least one of the first guide and the second guide is the second guide.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a throttle valve device that can be used as, for example, an electronic throttle device for controlling intake air of an engine, an EGR valve used in an exhaust gas circulation system, an intake passage pressure control valve for a diesel engine, and a negative pressure control valve for controlling hydrogen concentration of a fuel cell. More specifically, the present disclosure relates to a throttle valve device that maintains a valve at a slightly open position (hereinafter, this position is referred to as a "valve intermediate opening position") rather than at a fully closed position where the valve is fully closed by a coil spring that biases the valve. BACKGROUND

[0002] For example, in an electronic throttle device, when the motor of the electronic throttle device does not generate driving force, the throttle valve is operated to stop at the valve intermediate opening position instead of at a fully closed position to close the intake passage, so that the vehicle can perform emergency running even if a failure occurs in an engine control unit that controls an operating state of the engine or in the electronic throttle.

[0003] In the electronic throttle device described in Patent Literature 1 (JP 2003-120335 A), a coil spring is used, and resin-made guides are arranged at both ends of the coil spring. When the throttle valve is rotated from the intermediate valve opening position to the fully closed position, one of the two resin-made guides serves as a stopper, and the other of the two resin-made guides rotates together with the coil spring. Conversely, when the throttle valve is rotated from the intermediate valve opening position to the fully opened position, the other of the two guides serves as a stopper, while one of the two guides rotates together with the coil spring.

[0004] However, in the electronic throttle device described in Patent Literature 1, one of the two guides on the body or the valve gear slides when the throttle valve rotates. Therefore, the resistance due to the sliding results in a large hysteresis, as indicated by a line "a" in Fig. 13, and therefore, it is difficult to accurately control rotation of the throttle valve in an opening direction or a closing direction across the valve intermediate opening position.

[0005] JP 2019 - 120 253 A discloses a throttle valve device comprising a body defining therein a passage and a motor compartment; a shaft extending in the passage of the body in a direction perpendicular to the passage; a pair of bearings arranged on both sides of the passage of the body, the pair of bearings rotatably supporting the shaft; a valve rotating together with the shaft to selectively open and close the passage; a motor arranged in the motor compartment of the body, the motor rotating in response to an electrical signal; a valve gear arranged coaxially with the shaft in the body, the valve gear being connected to the shaft via a lever such that the valve gear transmits rotation of the motor to the shaft.a coil spring disposed between the valve gear and the valve in the body, the coil spring applying a biasing force when the rotation of the motor is transmitted to the shaft; and a guide. A lever of the guide is, among other things, in contact with more than one end surface of the hub. DE 38 77 200 T2 discloses another similarly constructed throttle valve device. In this case, however, a guide is not in contact with a pair of bearings. SUMMARY

[0006] In view of the foregoing, an object of the present disclosure is to reduce a sliding resistance of a resin-made guide with respect to a body and a valve gear when the guide rotates.

[0007] In a first aspect of the present disclosure, a throttle valve device includes a body, a shaft, a pair of bearings, a valve, a motor, a valve gear, a coil spring, a first guide, and a second guide. The body defines a passage and a motor compartment. The shaft extends within the passage of the body in a direction perpendicular to the passage. The pair of bearings is disposed on both sides of the passage of the body, and the pair of bearings rotatably supports the shaft. The valve rotates together with the shaft to selectively open and close the passage. The motor is disposed in the motor compartment of the body. The motor rotates in response to an electrical signal. The valve gear is disposed coaxially with the shaft in the body. The valve gear is connected to the shaft via a lever, such that the valve gear transmits rotation of the motor to the shaft.The coil spring is arranged between the valve gear and the valve in the body. The coil spring applies a biasing force when the rotation of the motor is transmitted to the shaft. The first guide covers one side of the coil spring. The second guide covers the other side of the coil spring. At least one of the first guide and the second guide has a circular holder facing an end surface of the coil spring, a spring end holding portion protruding outward from the circular holder and configured to hold a spring end of the coil spring, a hub rotatably connected to the shaft, and a connecting portion connecting the hub and the circular holder. The first guide is in contact with the lever only at one end surface of the hub when the at least one of the first guide and the second guide is the first guide.The second guide is in contact with one of the pair of bearings located closer to the valve gear on an end surface of the hub when the at least one of the first guide and the second guide is the second guide.

[0008] As a result, it is possible to reduce a contact area between the coil spring and the guide when the guide rotates.

[0009] In a second aspect of the present disclosure, the connecting portion of at least one of the first guide and the second guide has a thickness in an axial direction smaller than that of the hub and the circular holder such that a space is defined by the connecting portion, the hub and the circular holder.

[0010] As a result, a part of at least one of the valve gear and body components can be accommodated in the internal space, and thus the throttle valve device can be downsized.

[0011] In a third aspect of the present disclosure, the connecting portion and the hub form a T-shape in a cross section.

[0012] In a fourth aspect of the present disclosure, the connecting portion and the hub form an L-shape in a cross section.

[0013] In a fifth aspect of the present disclosure, at least one of the first guide and the second guide is the first guide, and the hub of the first guide is tapered toward the lever.

[0014] As a result, the contact area or contact surface between the first guide and the lever can be reduced.

[0015] In a sixth aspect of the present disclosure, at least one of the first guide and the second guide is the second guide, and the hub of the second guide is tapered toward the one of the pair of bearings.

[0016] As a result, the contact area between the second guide and the bearing can be reduced.

[0017] In a seventh aspect of the present disclosure, the connecting pin has a disk shape and has a radial rib formed on an outer surface of the connecting portion.

[0018] As a result, the strength of the connecting section can be increased.

[0019] In an eighth aspect of the present disclosure, the at least one of the first guide and the second guide is the first guide and the second guide, and a predetermined gap is formed between the hub of the first guide and the hub of the second guide.

[0020] Therefore, the sliding resistance between the first guide and the second guide can be eliminated.

[0021] In a ninth aspect of the present disclosure, the first guide and the second guide have the same shape.

[0022] As a result, assembly time can be shortened, assembly setup costs can be reduced, and component costs can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosure, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims, and the accompanying drawings. Fig. Figure 1 is a vertical cross-sectional view of an electronic choke. Fig. 2 is a front view of a body. Fig. 3 is a perspective view showing a coil spring and first and second guides. Fig. 4 is a front view of a first guide. Fig. 5 is a side view of the first guide shown in Fig. 4 is shown. Fig. 6 is a cross-sectional view taken along a line VI-VI in Fig. 4. Fig. 7 is a rear view of the first guide shown in Fig. 4 is shown. Fig. 8 is a front view of the coil spring arranged in the first guide. Fig. 9 is a side view of the first guide shown in Fig. 8 is shown. Fig. 10 is an enlarged view of a section X in Fig. 6. Fig. 11 is a cross-sectional view of the first and second guides before assembly. Fig. 12 is a cross-sectional view of the first and second guides after assembly. Fig. Figure 13 is a diagram showing hysteresis. Fig. 14 is a cross-sectional view of a guide according to a modification. Fig. 15 is a cross-sectional view of a guide according to another modification. Fig. 16 is a front view showing a valve gear of Fig. 2 shows. Fig. 17 is a cross-sectional view taken along a line XVII-XVII in Fig. 16. Fig. 18A is a cross-sectional view along line XVIII-XVIII of Fig. 17 at an intermediate valve opening position. Fig. 18B is a cross-sectional view along line XVIII-XVIII of Fig. 17 in a fully closed position. Fig. 18C is a cross-sectional view taken along a line XVIII-XVIII of Fig. 17 in a fully open position. Fig. 19A is a cross-sectional view taken along a line XIX-XIX in Fig. 17 at the valve intermediate opening position. Fig. 19B is a cross-sectional view taken along a line XIX-XIX in Fig. 17 in the fully closed position. Fig. 19C is a cross-sectional view along line XIX-XIX in Fig. 17 in the fully open position. DETAILED DESCRIPTION

[0024] An embodiment in which the present disclosure is applied to an electronic throttle device will be described below with reference to the drawings. As described above, the throttle valve device of the present disclosure can be widely used as a throttle valve device such as an EGR valve, a diesel engine intake passage pressure control valve, and a fuel cell negative pressure control valve. Therefore, the terms throttle shaft, throttle valve, and the like are used because the present invention is applied to the electronic throttle device, but the uses of the shaft and valve are not necessarily limited to the throttle.

[0025] Fig. 1 is a vertical cross-sectional view of the electronic throttle device. An outline of the electronic throttle device 1 will be described with reference to Fig. 1. The electronic throttle device 1 is arranged in an engine compartment and controls a flow rate of intake air drawn into an engine. An engine control unit (not shown) calculates an optimal intake amount according to a driver's accelerator pedal operation, an engine rotation state, and the like, and outputs a rotation amount according to the calculation results to the engine 100.

[0026] The motor 100 is arranged in a motor compartment 330 of a body 300, and the rotation of the motor 100 is transmitted to a reduction mechanism 200 via a pinion 102 that is press-fitted and fixed to a motor shaft 101. As shown in Fig. 2, in the reduction mechanism 200, a large-diameter gear portion 202 of an intermediate gear 201 meshes with the motor pinion 102. The intermediate gear 201 is supported to be rotatable around the intermediate shaft 203. The intermediate shaft 203 is press-fitted and fixed in a fitting hole 301 of the body 300.

[0027] A small-diameter gear portion 204 of the intermediate gear 201 meshes with tooth portions 211 formed in an arc shape on an outer peripheral surface of the valve gear 210, and the rotation of the motor pinion 102 is transmitted to the valve gear 210 via the intermediate gear 201. Therefore, the reduction mechanism 200 includes the motor pinion 102, the large-diameter gear portion 202 and the small-diameter gear portion 204 of the intermediate gear 201, and the tooth portions 211 of the valve gear 210. The reduction rate is such that when the motor shaft 101 rotates 28 times, a tooth portion 211 of the valve gear 210 advances clockwise or counterclockwise.

[0028] Semicircular arc-shaped magnets 220 and 221 are arranged in an inner circumference of a cup-shaped central portion 212 of the valve gear 210, and the magnets 220 and 221 form a magnetic circuit. A disc-shaped lever 401 is arranged in a deep portion (the lower side in Fig. 1) of the cup-shaped central portion 212 of the valve gear 210. The magnets 220 and 221 and the lever 401 are insert-molded with the valve gear 210.

[0029] The lever 401 is fixed to one end of the throttle shaft 402 by swaging. Therefore, the valve gear 210 is connected to the throttle shaft 402 via the lever 401, and rotation of the valve gear 210 is transmitted to the throttle shaft 402. A disc-shaped throttle valve 400 is fixed to the throttle shaft 402 by screws 403, and the throttle valve 400 increases or decreases the opening area of ​​an intake passage 320 formed in the body 300 according to its rotation.

[0030] An open end 303 (the upper side in Fig. 1) The body 300 is covered with a cover 500. The cover 500 is made of a resin such as polybutylene terephthalate, and ribs are formed at specific locations to increase its strength. A pair of rotation angle sensors 510, which are Hall ICs, are arranged in the cover 500 at positions corresponding to an axis 407 of the throttle shaft 402. The rotation angle sensor 510 is fixed to the cover 500. However, a pair of arc-shaped magnets 220 and 221, which are insert-molded with the valve gear 210, are arranged on an outer periphery of the rotation angle sensor 510. Then, the magnets 220, 221 rotate around the axis 407 according to the rotation of the throttle shaft 402. Accordingly, the magnetic circuit is moved to a position corresponding to the rotation angle of the throttle valve 400.The rotation angle sensor 510 detects the change in the magnetic force caused by the position change in the magnetic circuit and thus detects an opening degree of the throttle valve 400. Then, the detected position information is fed back to an engine control unit (not shown).

[0031] The throttle shaft 402 is rotatably supported in the body 300 by bearings 405 and 406 arranged on both sides of the throttle valve 400. The bearing 405 is a plain bearing, and the bearing 406 is a ball bearing. An opening 302 of the body 300 for the throttle shaft 402 is an opening for the bearing 405 to be inserted and is covered by the cover 310.

[0032] A space 321 for accommodating the valve gear 210 is formed in the body 300, and a coil spring 450 for urging the throttle shaft 402 is arranged in this space 321. As in Fig. 3, the coil spring 450 has a cylindrical shape and both ends 451, 452 thereof are bent to protrude radially outward.

[0033] Fig. 4 is a front view of the first guide 460, and Fig. 5 is a side view of the first guide 460. As in Fig. 4 and Fig. As shown in Fig. 5, a circular retainer 462 is formed in the first guide 460 to have a corresponding shape of the coil spring 450. An end surface 453 of the coil spring 450 is housed in the retainer 462. The first guide 460 has a boss formed in the center thereof, and the throttle shaft 402 is fit with clearance into a center hole 464 of the boss 463. In other words, the first guide 460 is rotatably arranged around the throttle shaft 402.

[0034] The hub 463 and the holder 462 of the first guide 460 are connected by a disc-shaped connecting portion 465. Ribs 466 and 467 for increasing strength are formed on both surfaces of the connecting portion 465. As shown in Fig. 4, eight ribs 466 are formed on a surface of the connecting portion 465 over the entire length in the radial direction from the hub 463 to the holder 462. The ribs 466 are arranged at intervals of 45 degrees in the circumferential direction. As shown in Fig. 6 and Fig. As shown in Fig. 7, eight ribs 467 are formed on the other surface of the connecting portion 465 only around the holder 462. The ribs 467 are arranged at 45-degree intervals in the circumferential direction. Fig. 6 is a cross-sectional view along a line VI-VI of Fig. 4, but it is upside down with reference to Fig. 1 shown.

[0035] A spring end holding portion 468 is formed to radially protrude from the circular holder 462 of the first guide 460. The spring end holding portion 468 has a holding surface 4681 that contacts the spring end 451, a hole 4682 through which the spring end 451 is inserted, and a protector 4683 that covers the spring end 451. The hole 4682 improves an assembly process of the coil spring 450, and the protector 4683 prevents the coil spring 450 from falling off.

[0036] Fig. 8 and Fig. 9 shows a portion of the coil spring 450 disposed in the circular holder 462 and the spring end holding portion 468 of the first guide 450. In this state, the spring end 451 is engaged with the first guide 460, but at the same time, the spring end 452 is also engaged with the second guide 461. In this state, the coil spring 450 is preloaded. Due to the preload, the spring end 451 is pressed against the holding surface 4681.

[0037] Fig. 10 is an enlarged view of a section X in Fig. 6. As in Fig. 10, the hub 463 is directed toward an outer side (the lower side in Fig. 19). The width of the hub 463 has a minimum value at an outermost portion 4631. Furthermore, since the outermost portion 4631 has a corner with a curved surface, the essential width thereof is further reduced.

[0038] The above description is made with respect to the first guide 460, but since the second guide 461 has the same shape as the first guide 460, the description of the first guide 460 can be applied to the second guide 461. Also in the relationship between Fig. 6 and Fig. 1 is the first guide 460 based on Fig. 6, but the second guide 461 has the same shape as in Fig. 1 is shown.

[0039] In this way, by forming the first guide 460 and the second guide 461 to have the same shape, it is not necessary to classify the first guide 460 and the second guide 461 at the time of assembly, and as a result, assembly time can be reduced. Furthermore, by having the same shape, the cost of assembly equipment can be reduced, and the cost of components can be reduced.

[0040] However, the second guide 461 is used in an opposite direction with respect to the first guide 460. Therefore, as shown in Fig. 3, the circular holder 462 of the first guide 460 houses and holds one end surface 453 of the coil spring 450, while the circular holder portion 462 of the second guide 461 houses and holds the other end surface 454 of the coil spring 450.

[0041] As in Fig. 1, the first guide 460, the coil spring 450 and the second guide 461 are arranged around the throttle shaft 402 at a rear side (the lower side in Fig. 1) of the valve gear 210. Then, the outermost portion 4631 of the hub 463 of the first guide 460 is brought into contact with the metal-made lever 401, and the outermost portion 4631 of the hub 463 of the second guide 461 is fitted with an inner ring 4061 (see Fig. 1) of the ball bearing 406. Note that 4062 denotes an outer ring of the ball bearing, and 4063 denotes a ball in the drawings.

[0042] As described later, the body 300 is formed with a spring receiver that contacts the spring end holding portion 468 of the first guide 460 and the spring end holding portion 468 of the second guide 461 to receive the spring force of the coil spring 450. Furthermore, when each of the spring end holding portions 468 contacts the respective spring receiver, the throttle valve 400 maintains the intake passage 320 in an intermediate valve opening state by the biasing force of the coil spring 450. Although this intermediate valve opening state is in a closed position, the throttle valve 400 does not completely close the intake passage 320 to allow emergency driving in the event of a failure. That is, the intake passage 320 is slightly open, allowing a predetermined amount of intake air to flow into the intake passage 320.

[0043] Next, the assembly process of the coil spring 450 will be described. When the coil spring 450 is not preloaded, the first guide 460 and the second guide 461 are substantially separated from each other by the coil spring 450, as shown in Fig. 11. Even in the state of Fig. 11, the circular holder 462 of the first guide 460 accommodates one end surface 453 of the coil spring 450, while the spring end holding portion 468 holds the spring end 451. Furthermore, the circular holder 462 of the second guide 461 accommodates the other end surface 454 of the coil spring 450, while the spring end holding portion 468 holds the spring end 452.

[0044] From this state, a preload is applied to the coil spring 450, so that the spring end holding portion 468 of the first guide 460 is brought into contact with the spring receiver of the valve gear 210 and the spring end holding portion 468 of the second guide 461 is brought into contact with the spring receiver of the body 300. In this state, as shown in Fig. 12, a gap between the first guide 460 and the second guide 461 is narrowed. However, in this example, even if the gap is narrowed by the pressure of the coil spring 450, a certain gap a may still be formed between the boss 463 of the first guide 460 and the boss 463 of the second guide 461.

[0045] Therefore, the contact by the first guide 460 and the contact by the second guide 461 in an assembled state are only the contact between the outermost portion 4631 of the hub 463 of the first guide 460 and the metal-made lever 401 and the contact between the outermost portion 4631 of the hub 463 of the second guide 461 and the inner ring 4061 of the ball bearing 406. Therefore, as described below, a sliding resistance generated during rotation is drastically reduced.

[0046] When the throttle valve 400 opens the intake passage 320 to increase the engine speed, one end 451 of the coil spring 450 is held at one position, while the other end 452 thereof moves according to the rotation of the throttle shaft 402. In response to this movement, the coil spring 450 applies a restoring force to the throttle shaft 402, the valve gear 210, and ultimately the engine 100.

[0047] Therefore, when the valve is rotated from the intermediate opening position to the fully open position, the first guide 460 does not rotate, and only the second guide 461 rotates. As a result, a relative positional change occurs between the first guide 460, which does not rotate, and the throttle shaft 402, which rotates. However, due to the positional change of the first guide 460, sliding along the axial direction of the throttle shaft 402 is performed only between the outermost portion 4631 of the hub 463 and the metal-made lever 401, and therefore, the contact area for sliding becomes extremely small. This applies to the rotation of the throttle valve 400 when the throttle valve 400 returns from the fully open position to the valve intermediate opening position.

[0048] On the other hand, when the throttle valve 402 closes the intake passage 320 to bring the engine into an idling state, the throttle shaft 402 rotates from the valve intermediate opening position to the fully closed position. In this case, the other end 452 of the coil spring 450 is held at one position, and the one end 451 moves according to the rotation of the throttle shaft 402, unlike the fully opening process described above. Then, the coil spring 450 applies an opening force to the throttle shaft 402, the valve gear 210, and finally the engine 100 according to this movement.

[0049] Similarly to the fully open situation, the position change relative to the throttle shaft 402 occurs in the guide held in position, which in this case is the second guide 461. Sliding along the axial direction of the throttle shaft 402 according to the change in the position of the second guide 461 during relative rotation is performed between the outermost portion 4631 of the hub 463 of the second guide 461 and the inner ring 4061 of the ball bearing 406. Also in this case, the contact area during sliding is extremely small. This relative position change is the same when the throttle valve 402 returns from the fully closed position to the valve intermediate opening position.

[0050] This movement is made with reference to Fig. 16 to 19 described. Fig. 16 shows a section of the valve gear 210 in Fig. 2 at a position of the valve intermediate opening position. Fig. 17 is a cross-sectional view along line XVII-XVII in Fig. 16, and Fig. 18 and Fig. 19 are cross-sectional views along a line XVIII-XVIII and XIX-XIX in Fig. 17. Fig. 18A and Fig. 19A show the valve intermediate opening position, Fig. 18B and Fig. 19B show the fully closed position, and Fig. 18C and Fig. 19C shows the fully open position.

[0051] As in Fig. 18A and Fig. 18B, the spring end holding portion 468 of the first guide 460, which holds the spring end 451, is in contact with a locking pin 305 of the body 300, and the valve gear 210 simply separates away from the spring end holding portion 468 during a period between the valve intermediate opening position ( Fig. 18A) and the fully closed position ( Fig. 18B). In contrast, the spring end holding portion 468 moves in the clockwise direction through the valve gear 210 during a period from the valve intermediate opening position ( Fig. 18A) to the fully open position ( Fig. 18C).

[0052] The movement of the second guide 461 is in Fig. 19A and Fig. 19B. The spring end holding portion 468, which holds the spring end 452, moves in the counterclockwise direction inside a movement groove 306 of the body 300 according to the rotation of the valve gear 210 during a period between the valve intermediate opening position ( Fig. 19A) and the fully closed position ( Fig. 19B). On the other hand, the spring end holding portion 468 is held in engagement with a locking end 307, which is one end of the moving groove 306 of the body 300, during a period from the valve intermediate opening position ( Fig. 19A) to the fully open position ( Fig. 19C). Thus, the spring end holding portion 468 does not move.

[0053] As described above, according to the present embodiment, when the throttle valve 402 is moved against the biasing force of the coil spring 450 to the fully open position from the valve intermediate opening position as a middle position, and when the throttle valve 402 is rotated with the biasing force of the coil spring 450 to the valve intermediate opening position from the fully open position, sliding occurs with only a small contact area between the outermost portion 4631 of the boss 463 of the first guide 460 and the metal lever 401.In contrast, when the throttle valve 402 is rotated against the biasing force of the coil spring 450 to the fully closed position from the valve intermediate opening position and when the throttle valve 402 is rotated with the biasing force of the coil spring 450 to the valve intermediate opening position from the fully closed position, sliding occurs only with a small contact area between the outermost portion 4631 of the boss 463 of the second guide 461 and the inner ring 1061.

[0054] In particular, since sliding occurs through the two guides 460 and 461 on the respective hub 463, the sliding occurs with a minimum radius, and the sliding moment due to sliding resistance can also be minimized. Furthermore, since the lever 401 and the inner ring 4061 are made of a dense metal, the friction coefficient is small, and the sliding resistance for the guides 460 and 461, which are made of a resin, can be further reduced. Therefore, as shown in Fig. 13, the hysteresis is significantly reduced. It should be noted that in Fig. 13 "a" denotes a hysteresis of a comparative structure in which the resin guide slides in full contact with the body 300 and the valve gear 210, and "b" denotes a hysteresis of this embodiment.

[0055] Although the bearing 406 is a ball bearing in this embodiment, the bearing 406 may be a plain bearing similar to the bearing 405. Even in this case, the friction coefficient is small and the sliding resistance for the second guide 461 is also small. Alternatively, the plain bearing may be made of a sintered metal impregnated with oil.

[0056] Furthermore, in this embodiment, the spring end 452 of the coil spring 450 moves close to the second guide 461 during rotation from the valve intermediate opening position to the fully closed position, and the spring end 451 moves close to the first guide 460 during rotation from the valve intermediate opening position to the fully closed position. However, the operation of the coil spring 450 may be reversed. Although the rotation of the motor 100 is reversed, the operation is the same as in this embodiment. As shown in Fig. As can be seen from Figure 13, the amount of rotation of the throttle shaft 402 is larger when the throttle valve 403 rotates from the intermediate valve opening position to the fully open position than from the intermediate valve opening position to the fully closed position. The friction coefficient of the bearing 406 is smaller than that of the lever 401. Therefore, the hysteresis reduction effect can be further increased by moving the spring end 452 of the coil spring 450, which is close to the second guide 461, when rotating from the intermediate valve opening position to the fully open position.

[0057] Although the above-described embodiment is a preferred embodiment, the shape of the hub 463 can be changed in various ways. It can be T-shaped, as in Fig. 14, or L-shaped, as shown in Fig.15. Since the space 469 is formed between the boss 463 and the connecting portion 465, regardless of whether the boss 463 is T-shaped or L-shaped, the axial length of the throttle shaft 402 of the electronic throttle device 1 can be reduced by effectively utilizing the space 469 to accommodate the protruding portion of the body 300 or the valve gear 210 therein.

[0058] Furthermore, in the example described above, the very small gap a is formed between the first guide 460 and the second guide 461. However, if hubs 463 of both guides 460 and 461 come into contact with each other due to an assembly error, such slight contact may be acceptable.

[0059] Furthermore, in the above example, the first guide 460 and the second guide 461 have the same shape to reduce the total assembly process time, the assembly equipment cost, and the component cost. However, if it is necessary to make the shapes of the first guide 460 and the second guide 461 different from each other due to the shape of the valve gear 210 or the body 300, it is inevitable to allow the shape change. In this case, it is inevitable that one of the first guide 460 and the second guide 461 at a minimum comes into contact with the body 300 or the valve gear 210 at a position different from the boss 463. Furthermore, in the above example, the connecting portion has a disc shape, but it may have another shape.

[0060] A throttle valve device has a body (300), a shaft (402), a pair of bearings (405, 406), a valve (400), a motor (100), a valve gear (210), a coil spring (450), a first guide (460) and a second guide (461). At least one of the first guide (460) and the second guide (461) has a circular holder (462) facing an end surface (453, 454) of the coil spring (450), a spring end holding portion (468) projecting outward from the circular holder (462) and configured to hold a spring end (451, 452) of the coil spring (450), a hub (463) rotatably connected to the shaft (402), and a connecting portion (465) connecting the hub (463) and the circular holder (462). The first guide (460) is in contact with a lever (401) only at one end surface of the hub (463).The second guide (461) is in contact with one (406) of the pair of bearings close to the valve gear (210) on an end surface of the hub (463).

Claims

[1] Throttle valve device with: a body (300) defining therein a passage (320) and an engine compartment (330); a shaft (402) extending in the passage of the body in a direction perpendicular to the passage; a pair of bearings (405, 406) arranged on both sides of the passage of the body, the pair of bearings rotatably supporting the shaft; a valve (400) rotating together with the shaft to selectively open and close the passage; a motor (100) disposed in the motor compartment of the body, the motor rotating in response to an electrical signal; a valve gear (210) arranged coaxially with the shaft in the body, the valve gear being connected to the shaft via a lever (401) such that the valve gear transmits rotation of the motor to the shaft; a coil spring (450) disposed between the valve gear and the valve in the body, the coil spring applying a biasing force when the rotation of the motor is transmitted to the shaft; a first guide (460) covering one side of the coil spring; and a second guide (461) covering the other side of the coil spring; wherein at least one of the first guide and the second guide has the following: a circular holder (462) facing an end surface (453, 454) of the coil spring; a spring end holding portion (468) projecting outwardly from the circular holder and configured to hold a spring end (451, 452) of the coil spring; a hub (463) rotatably connected to the shaft; and a connecting portion (465) connecting the hub and the circular holder, wherein the first guide is in contact with the lever only at one end surface of the hub when at least one of the first guide and the second guide is the first guide, and the second guide is in contact with one (406) of the pair of bearings located close to the valve gear on an end surface of the hub when the at least one of the first guide and the second guide is the second guide. [2] The throttle valve device according to claim 1, wherein the connecting portion (465) of at least one of the first guide and the second guide has a thickness in an axial direction smaller than that of the boss (463) and the circular holder such that a space (469) is defined by the connecting portion, the boss and the circular holder. [3] The throttle valve device according to claim 2, wherein the connecting portion and the boss form a T-shape in a cross section. [4] The throttle valve device according to claim 2, wherein the connecting portion and the boss form an L-shape in a cross section. [5] Throttle valve device according to one of claims 1 to 4, wherein at least one of the first guide and the second guide is the first guide, and the hub of the first guide is tapered towards the lever. [6] Throttle valve device according to one of claims 1 to 5, wherein at least one of the first guide and the second guide is the second guide, and the hub of the second guide is tapered towards one of the pair of bearings. [7] A throttle valve device according to any one of claims 1 to 6, wherein the connecting portion has a disc shape and has a radial rib (466, 467) formed on an outer surface of the connecting portion. [8] Throttle valve device according to one of claims 1 to 7, wherein at least one of the first guide and the second guide is the first guide and the second guide, and a certain gap (a) is formed between the hub of the first guide and the hub of the second guide. [9] A throttle valve device according to any one of claims 1 to 8, wherein the first guide and the second guide have a same shape.

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