Intake air controller for internal combustion engine and manufacturing the same

Abstract: A throttle assembly (30) including a bore wall (40) to which a seal member (60) is previously attached is inserted into a key-like slot (21) of an intake air passage body (20), and flanges (25, 35) are fixed to each other by screws (65). A bore inner wall (45) of the bore wall (40) is placed to correspond to an inner wall of an intake air passage (11), and the seal member (60) completely seals between the intake air passage body (20) and the throttle assembly (30). That is, the throttle assembly (30) including the seal member (60) is inserted into the key-like slot (21), so that the throttle assembly (30) is easily attached to the intake air passage body (20), a sealing mechanism therebetween is simplified, and a stress strain of the bore wall (40) is prevented.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention relates to an intake air controller suitable for use in an internal combustion engine, to which a throttle assembly including a throttle valve is attached, and to a method for assembling an intake air controller. 2. Description of Related Art: US-A-5,342,773 discloses an intake air controller for an internal combustion engine, to which a throttle assembly including a throttle valve is attached. The throttle assembly made of resin is attached to intake air passages of the intake air controller. A sealing mechanism between the throttle assembly and the intake air passages includes O-rings axially sealing therebetween and a U-shaped pin preventing the throttle assembly from separating from the intake air passage. However, according to US-A-5,342,773, since the throttle assembly is disposed between the intake air passages, both ends of the throttle assembly have to be sealed. Thus, the throttle assembly is not easily attached to the intake passages, and the sealing mechanism is complicated to prevent a stress strain. A further conventional intake air controller is known from JP-A-10-103089. A throttle assembly includes a throttle valve adjusting an amount of air flowing into an internal combustion engine. The throttle assembly is attached to an intake air passage body. A seal member seals between the throttle assembly and the intake air passage body. The throttle assembly comprises at one side an insertion portion. The insertion portion is inserted into an insertion hole of a throttle body slot of the intake air passage body. A clearance is provided between the insertion portion and the insertion hole. The insertion portion per se does not act as alignment member but is fixed to the intake air passage body by a screw. SUMMARY OF THE INVENTION It is an object of the present invention to provide an intake air controller and a method for assembling an intake air controller in which a throttle body can be easily attached while a correct position is guaranteed. According to the invention, this object is achieved by an intake air controller having the features of claim 1 and a method for assembling an intake air controller having the features of claim 7. Advantageous further developments are set out in the dependent claims. According to the present invention, the intake air controller is formed such that the throttle body can be easily attached to the intake air passage body, a sealing mechanism therebetween is simplified, and stress strain due to fixing force is prevented. The throttle assembly to which a seal member is previously attached is inserted into a slot, and first and second flanges are fixed to each other. That is, the throttle assembly including the seal member is inserted into the slot, so that the throttle assembly is easily attached to the intake air passage body, and a sealing mechanism therebetween is simplified. A first flange formed in the throttle body is fixed to a second flange formed in the intake air passage body by a screw, a snap fit, or a spring cramp. Thus, a sealing performance is improved and a bore wall is not distorted due to the fixing force, so that a throttle valve smoothly operates to attain an appropriate clearance between the throttle valve and the bore wall, thereby improving the control of the intake air flow amount. Since an additional insertion portion is installed into and held by a holder portion while no seal member is provided therebetween, the axis of the insertion portion is made to correspond to the axis of the holder portion. Thus, a clearance between the outer wall of the insertion portion and the inner wall of the slot is constantly maintained, so that the sealing performance of the seal member is highly improved. Further, the insertion portion is firmly supported by the holder portion, thereby preventing the insertion portion from vibrating due to an engine vibration. BRIEF DESCRIPTION OF THE DRAWINGS The object and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments thereof when taken together with the accompanying drawings in which: FIG. 1 is a perspective view showing an intake air passage body and a throttle assembly comparative example; FIG. 2 is a bottom view showing the throttle assembly comparative example; FIG. 3 is a perspective view showing an intake air passage body and a throttle assembly of a further comparative example; FIG. 4 is a perspective view showing an intake air passage body and a throttle assembly of a further comparative example; FIG. 5 is a perspective view showing an intake air passage body and a throttle assembly of a further comparative example; FIG. 6 is a bottom view showing the throttle assembly of Fig. 5; FIG. 7 is a perspective view showing an intake air passage body and a throttle assembly (first embodiment); FIG. 8 is a perspective view showing an intake air passage body and a throttle assembly (second embodiment); FIG. 9 is a bottom view showing the throttle assembly (third embodiment); FIG. 10 is a perspective view showing an intake air passage body and a throttle assembly of a further comparative example, and FIG. 11 is a bottom view showing the throttle assembly of Fig. 10. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS (Comparative Example) In the comparative example, as shown in FIG. 1, an intake air controller 100 is used for an internal combustion engine, and includes an intake air passage body 20 and a throttle assembly 30. The intake air passage body 20 is formed within an intake air passage block 10 including an air passage 11. The intake air passage body 20 is made of resin, and the throttle assembly 30 is attached to the intake air passage body 20. The intake air passage body 20 includes a key-like slot 21 and a flange 25. The key-like slot 21 is perpendicularly formed to an air-flow direction in the air passage 11, and the flange 25 is formed around the key-like slot 21. The key-like slot 21 includes a cylindrical hole 21a at the bottom thereof. The throttle assembly 30 includes a throttle valve 31, a bore wall 40 made of resin, a throttle shaft 32, a motor chamber 50, and a flange 35. The throttle valve 31 adjusts an amount of intake air flowing into the engine. The throttle shaft 32 supports the throttle valve 31 with respect to the bore wall 40. The motor chamber 50 contains an electric motor (not illustrated) and a throttle position sensor (not illustrated). The electric motor is connected to the throttle shaft 32 and drives the throttle valve 31. The throttle position sensor detects an actual opening position of the throttle valve 31. The flange 35 is to be attached to the flange 25 of the intake air passage body 20. The bore wall 40 defines a cylindrical portion 41 and a side wall 42, and the flange 35 defines a root portion 35a where the bore wall 42 protrudes. As shown in FIGS. 1 and 2, a single rubber seal member 60 is provided at the cylindrical portion 41, side wall 42, and the root portion 35a of the flange 35. An assembly procedure of the intake air controller 100 of the present embodiment will be explained with reference to FIGS. 1 and 2. The bore wall 40 including the cylindrical portion 41 and the side wall 42 is inserted into the key-like slot 21 of the flange 25 perpendicularly to the intake air-flow direction. At this time, a return spring urges the throttle valve 31 at the original position thereof, so that the throttle valve 31 is entirely placed within the bore wall 40 in the air-flow direction. Thus, when the bore wall 40 is being inserted into the key-like slot 21, the edge of the throttle valve 31 does not contact the inner surface of the key-like slot 21. When the bore wall 40 is completely inserted into the key-like slot 21 and the cylindrical portion 41 is inserted into the cylindrical hole 21a, the seal member 60 is located between the cylindrical portion 41, the side wall 42 and the inner surface of the key-like slot 21, and is located between the root portion 35a and the top surface of the flange 25 of the intake air passage body 20. The flange 35 of the throttle assembly 30 includes four screw holes 39, and the flange 25 of the intake air passage body 20 also includes four screw holes 29. Screws 65 fix the flange 35 of the throttle assembly 30 to the flange 25 of the intake air passage body 20 through the screw holes 29, 39. In this way, a bore inner wall 45 of the bore wall 40 is placed to correspond to the inner wall of the intake air passage 11, and the seal member 60 completely seals between the intake air passage body 20 and the throttle assembly 30. After that, the electric motor and the throttle position sensor are electrically connected to an outside control unit through a connector 70 and a wire harness. The intake air amount into the engine is adjusted based on the opening position of the throttle valve 31 with respect to the bore inner wall 45. As described above, the bore wall 40 to which the seal member 60 is previously attached is inserted into the key-like slot 21. That is, the throttle assembly 20 including the seal member 60 is inserted into the key-like slot 21 perpendicularly to the air -flow direction in the intake air passage 11, so that the throttle assembly 30 is easily attached to the intake air passage body 20, and a sealing mechanism therebetween is simplified. Further, the screws 65 fix the 35 to the flange 25 at positions far from the throttle vale 31 and the bore wall 40. Thus, the flange 35 is easily fixed to the flange 25, and the bore inner wall 45 is not distorted due to the fixing force, so that the bore radius of the bore inner wall 45 is accurately maintained. Thus, the electric motor smoothly operates the throttle valve 31 to attain an appropriate clearance between the throttle valve 31 and the bore inner wall 45, thereby improving the control of the intake air flow amount. In the above-described comparative example, the flange 35 of the throttle assembly 30 is fixed to the flange 25 of the intake air passage body 20 by the screws 65. Alternatively, the flange 35 may be fixed to the flange 25 by a snap fit or a spring cramp. As shown in FIG. 3, the flange 35 is fixed to the flange 25 by a snap fit. The snap fit includes concave portions 26 formed within the flange 25, and projections 36 formed within the flange 35. Each projection 36 is inserted into each concave portion 26 to fix the flange 35 to the flange 25. As shown in FIG. 4, the flange 35 of the throttle assembly 30 is fixed to the flange 25 of the intake air passage body 20 by spring cramps 90. The flange 25 includes four extending corners 27, and the flange 35 also includes four extending corners 37. The extending corners 27 and 37 are put together, and the spring cramps 90 are fit to cover both extending corners 27 and 37 while being elastically transformed, so that the flange 35 is fixed to the flange 25. (Further Comparative Example) In the further comparative example, as shown in FIG. 5, an intake air controller 100 is used for an internal combustion engine, and includes an intake air passage body 20 and a throttle assembly 30. The intake air passage body 20 is formed within an intake air passage block 10 including an air passage 11. The intake air passage body 20 is made of resin, and the throttle assembly 30 is attached to the intake air passage body 20. The bore wall 40 has a large thickness in the air flow direction in comparison with the bore wall 40 in the first embodiment, and is substantially formed in pentagon surrounding the bore inner wall 45 in cross section perpendicular to the air flow direction. That is, a bottom end 41 of the bore wall 40 in the second embodiment is not cylindrically formed. The intake air passage body 20 includes a slit-like slot 21 perpendicularly formed to an air-flow direction in the air passage 11, into which the bore wall 40 and the bottom end 41 thereof is installed. Therefore, as shown in FIGS. 5 and 6, the shape of single rubber seal member 60 provided at the bottom end 41, the side wall 42, and the root portion 35a of the flange 35 is simplified. As in the other comparative example, the screws 65 fix the flange 35 of the throttle assembly 30 to the flange 25 of the intake air passage body 20 through the screw holes 29, 39. Thus, a bore inner wall 45 of the bore wall 40 is placed to correspond to the inner wall of the intake air passage 11, and the seal member 60 completely seals between the intake air passage body 20 and the throttle assembly 30. After that, the electric motor and the throttle position sensor are electrically connected to an outside control unit through a connector 70 and a wire harness. The intake air amount into the engine is adjusted based on the opening position of the throttle valve 31 with respect to the bore inner wall 45. As described above, the bore wall 40 to which the seal member 60 is previously attached is inserted into the slit-like slot 21. That is, the throttle assembly 30 including the seal member 60 is inserted into the slit-like slot 21 perpendicularly to the air-flow direction in the intake air passage 11, so that the throttle assembly 30 is easily attached to the intake air passage body 20, and a sealing mechanism therebetween is simplified as in the other comparative example. (First Embodiment) In the first embodiment, as shown in FIG. 7, a cylindrical insertion portion 411 is formed at the bottom of the cylindrical portion 41 in the first embodiment. The diameter of the insertion portion 411 is smaller than that of the cylindrical portion 41, so that a step 412 is formed at the bottom surface of the cylindrical portion 41. An insertion hole 211 is formed at the bottom of the cylindrical hole 21a. The diameter of the insertion hole 211 is smaller than that of the cylindrical hole 21a, so that a step 212 is formed at the bottom surface of the cylindrical hole 21a. When the bore wall 40 is inserted into the key-like slot 21, the insertion portion 411 is fit or press-inserted into the insertion hole 211, and the step 412 engages with the step 212. According to the comparative example, since the elastic seal member 60 is provided with the cylindrical portion 41, the axis of the cylindrical portion 41 may incline with respect to the axis of the cylindrical hole 21a when the bore wall 40 is inserted into the key-like slot 21. Under such a condition, it is difficult to maintain the accuracy of clearance between the outer wall of the bore wall 40 and the inner wall of the key-like slot 21. If the clearance becomes over an allowable amount, the seal member 60 may not sufficiently seal between the intake air passage body 20 and the throttle assembly 20. Further, even when the clearance accuracy is maintained, since the seal member 60 is made of elastic rubber, the bore wall 40 may vibrate in the key-like slot 21 due to an engine vibration. When the bore wall 40 vibrates, the throttle valve 31 is not appropriately located with respect to the air passage 11, so that the intake air flow amount is not well controlled. However, according to the first embodiment, since the additional insertion portion 412 is installed into the insertion hole 211 while no seal member 60 is provided therebetween, the bore wall 40 is correctly placed against the key-like slot 21. That is, the axis of the cylindrical portion 41 is made to correspond to the axis of the cylindrical hole 21a. Thus, the clearance between the outer wall of the bore wall 40 and the inner wall of the key-like slot 21 is constantly maintained, so that the sealing performance of the seal member 60 is highly attained. The insertion portion 412 is firmly supported by the insertion hole 211, thereby preventing the bore wall 40 from vibrating due to the engine vibration. Further, the insertion hole 211 is formed at the bottom of the cylindrical hole 21a to hold the front end area of the insertion portion 411 in an insertion direction. Thus, it is not necessary to change the opening shape of the key-like slot 21. (Second Embodiment) In the second embodiment, as shown in FIGS. 8 and 9, an additional insertion portion 411 and an additional insertion hole 211 are provided at a throttle assembly of Figs.5 and 6. As in the first embodiment, the insertion portion 411 is fit or press inserted into the insertion hole 211 while no elastic seal member is provided therebetween. Here, as shown in FIG. 9, the seal member 60 located on the bottom surface of the bore wall 40 avoids the cylindrical insertion portion 411 such that the insertion portion 411 is directly contacts the insertion hole 211. (Further comparative example) In the further comparative example, as shown in FIGS. 10 and 11, ring-like gaskets 600a and 600b are provided on the front and rear walls of the bore wall 41 respectively, to surround the air intake bore instead of the seal member 60 in the fourth embodiment. (Modifications) In the above-described embodiments, the electric motor is used to drive the throttle valve 31. Alternatively, a link throttle mechanism may drive a throttle valve directly based on an accelerate stroke.

Claims: An intake air controller (100) for an internal combustion engine comprising: a throttle assembly (30), said throttle assembly (30) including a throttle valve (31) adjusting an amount of air flowing into said internal combustion engine, a throttle body portion (40), a throttle shaft (32) supporting said throttle valve (31) with respect to said throttle body portion (40), a driving mechanism connected to said throttle shaft (32) and driving said throttle valve (31), and a first flange (35); an intake air passage body (20) to which said throttle assembly (30) is attached, said intake air passage body (20) including an intake air passage (11) leading the air into said internal combustion engine, a throttle body slot (21) into which said throttle assembly (30) is inserted as a single unit, and a second flange (25) to which said first flange (35) is fixed; and a seal member (60); sealing between said throttle assembly (30) and said intake air passage body (20) perpendicularly to the flow direction of the air, wherein said throttle assembly (30) further comprises a bottom end portion at a bottom side of said throttle body portion (40) and an insertion portion (411), said bottom side being inserted into said throttle body slot (21), said insertion portion having a transverse dimension less than a corresponding transverse dimension of said bottom end portion, said seal member extending along a circumferential periphery of the throttle assembly, said seal member being received within and being in engagement with said throttle body slot of said intake air passage body so as to define a peripheral, circumferential seal between said intake air passage and said throttle assembly, said intake air passage body (20) further comprises a holder portion receiving said bottom end portion, and an insertion hole (211) into which said insertion portion (411) is inserted, said insertion portion (411) and said insertion hole (211) having a corresponding size and shape for aligning the throttle assembly (30) and the intake air passage body (20), said insertion portion (411) being directly disposed in said insertion hole (211) in the absence of a sealing member therebetween, whereby the insertion portion (411) is provided solely as an alignment structure to square and center the throttle assembly within the air intake passage body through the throttle body slot during installation and in operation. An intake air controller according to claim 1, wherein said insertion portion (411) is press-inserted into said insertion hole (211). An intake air controller according to claim 1, wherein said holder portion holds a front end area of said bottom end portion in an insertion direction thereof. An intake air controller according to claim 1, wherein said insertion portion (411) protrudes from a bottom side of said bottom end portion. An intake air controller according to claim 1, wherein said bottom end portion is defined as a cylindrical portion at the bottom side of said throttle body portion (40), said insertion portion (411) protrudes from a bottom end of said cylindrical portion, a diameter of said insertion portion (411) is smaller than a diameter of said cylindrical portion, so that a first step (412) is formed at the bottom end of said cylindrical portion, said holder portion of said intake air passage body (20) defines a cylindrical hole (21a), said insertion hole (211) is formed at a bottom end of said cylindrical hole (21a), a diameter of said insertion hole (211) is smaller than a diameter of said cylindrical hole (21a), so that a second step (212) is formed at the bottom end of said cylindrical hole (21a), and when said insertion portion (411) is inserted into said insertion hole (211), said first step (412) engages with said second step (212). An intake air controller according to claim 1, wherein said throttle valve (31) is a butterfly type valve formed in a plate, said throttle body portion (40) is formed in a plate having a thickness in the flow direction of the air such that said throttle valve (31) is entirely placed within said throttle body portion (40) when said throttle valve (31) is at a closed position thereof. A method for assembling an intake air controller (100) for an internal combustion engine, said intake air controller (100) having a throttle assembly (30) including a throttle valve (31) adjusting an amount of air flowing into said internal combustion engine, a throttle body portion (40), a throttle shaft (32) supporting said throttle valve (31) with respect to said throttle body portion, a driving mechanism connected to said throttle shaft (32) and driving said throttle valve (31), a first flange (35), a bottom end portion at a bottom side of said throttle body portion (40), and an insertion portion (411),said bottom side being inserted into a throttle body slot (21),said insertion portion having a transverse dimension less than a corresponding transverse dimension of said bottom end portion, said intake air controller (100) having an intake air passage body (20) to which said throttle assembly (30) is attached, said intake air passage body (20) including an intake air passage leading the air into said internal combustion engine, the throttle body slot (21) into which said throttle assembly (30) is inserted perpendicularly to a flow direction of the air, a second flange (25) to which said first flange (35) is fixed, a holder portion for holding said bottom end portion, and an insertion hole (211) for receiving said insertion portion (411), said insertion portion (411) and said insertion hole (211) having a corresponding size and shape for aligning the throttle assembly (30) and the intake air passage body (20), and said intake air controller (100) having a seal member (60); sealing between said throttle assembly (30) and said intake air passage body (20) perpendicularly to the flow direction of the air, the method comprising: attaching said seal member (60); to said throttle assembly (30), said seal member extending along a circumferential periphery of the throttle assembly; inserting said throttle assembly (30) into said throttle body slot (21) of said intake air passage body (20) while inserting said insertion portion (411) into said insertion hole (211) without a seal member therebetween to thereby align said throttle assembly (30) and said intake air passage body (20) so that said bottom end portion is received and held by said holding portion, wherein the insertion portion (411) is used solely as an alignment structure to square and center the throttle assembly within the air intake passage body through the throttle body slot during installation and in operation, and wherein said sealing member is received within and is in engagement with said throttle body slot of said intake air passage body so as to define a peripheral, circumferential seal between said intake air passage and said throttle assembly; and fixing said first flange (35) to said second flange (25) while providing said seal member (60) between said throttle assembly (30) and said intake air passage body (20).

Inventors: TORII KATSUYA, TORII, KATSUYA
Applicants: DENSO CORP, DENSO CORPORATION
Application year: 2000
Main classification: F02D9
IPC codes: F02D9