JP2001303984A - Manufacturing method for throttle body for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a throttle body for an engine capable of easily manufacturing and reducing manufacturing costs by improving dimensional accuracy. SOLUTION: A correction pin 50 is inserted in bearing parts 41 and 42, and a cylinder part 20 and holding parts 31 and 32 are integrally formed with a resin material. After forming, the correction pin 50 is pulled out from the bearing parts 41 and 42, a throttle shaft is inserted therein, and a throttle valve is fixed on the throttle shaft. This can make the shaft center of the bearing parts 41 and 42 be an accurate and correspondent state, and improve the dimensional accuracy of the throttle body. Furthermore, a housing 11 is integrally formed, and compared with separate forming, this can reduce manufacturing man-hours in the throttle body 10, manufacture it easily, and reduce the manufacturing cost without necessity for joining the cylinder part 20 to the holding parts 31 and 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine (hereinafter referred to as "internal combustion engine").
The present invention relates to a method of manufacturing an engine throttle body that forms an air passage of an “internal combustion engine”.

[0002]

2. Description of the Related Art In recent years, it has been known that a housing of a throttle body is formed of resin in order to reduce the weight and cost of a throttle device. However, the throttle body needs to be formed into a complicated shape including irregularities such as a bearing portion of a throttle shaft and a mounting portion of an opening sensor.

Here, both ends of the throttle shaft are supported by the housing of the throttle body via the bearing. In order to hold the bearing portion, a concave portion is formed at two places in the housing, that is, at a portion where the throttle shaft is supported by the housing. When these two concave portions (hereinafter, referred to as holding portions) are formed, separate molds are separately prepared for resin-molding the respective holding portions, and the holding portions are generally formed by the molding dies. is there.

[0004]

However, the above-mentioned 2)
In the case where the holding portions are formed by separate molding dies, the shaft centers of both the molding dies must be set with very high precision and not molded with resin. There is a risk that the mind will be misaligned. In this case, even if the throttle shaft can be inserted into the bearing, the rotation of the throttle shaft due to the misalignment of the two bearings may cause an increase in the throttle shaft rotation torque, which may cause an extra drive loss when driving the throttle shaft. There is. Furthermore, since the two molds are precisely installed, the production cost may increase.

[0005] Even if the axis of the molding die for forming the two holding portions can be very accurately installed, the tolerance of the two bearings that hold both ends of the throttle shaft may result. In addition, there is a possibility that the shaft center at the portion supporting both ends of the throttle shaft is shifted. Note that Japanese Patent Application Laid-Open
As disclosed in Japanese Patent Publication No. 173227, a cylindrical portion of a housing formed of a composite material using a synthetic resin as a matrix and a holding portion of a throttle shaft formed separately from the housing are joined by welding or the like. A method of manufacturing a throttle body capable of preventing deformation of an intake passage has been proposed.

In this conventional technique, the holding portion of the throttle shaft is not formed by using the above-described dedicated mold. However, even in this prior art, if the holding portion formed separately from the cylindrical portion of the housing is not accurately joined to the cylindrical portion, the axis of the bearing portion that holds the throttle shaft is shifted. Further, even if the holding portion can be joined with high accuracy, the axial center of the two support portions of the throttle shaft eventually shifts due to the axial deviation due to the tolerance of the bearing portion itself. That is, even in the above-described conventional technology, there is still a problem that the axes of the two support portions that support the throttle shaft are not aligned.

Further, in the above-mentioned prior art, it is necessary to manufacture the holding portion of the throttle shaft separately from the cylindrical portion of the housing and further join the cylindrical portion and the holding portion. However, there is a problem that the number increases. The present invention has been made in order to solve such a problem, and the center of the support portion that reliably supports both ends of the throttle shaft at two points is not affected by the misalignment of the center of the bearing or the like. It is an object of the present invention to provide a method for manufacturing a throttle body for an engine that is possible. Another object of the present invention is to provide a method of manufacturing an engine throttle body that is easy to manufacture and can reduce manufacturing costs.

[0008]

According to the method for manufacturing a throttle body for an engine according to the first aspect of the present invention, a correcting shaft member is provided on a bearing portion of a shaft for fixing a valve member for controlling an opening degree of an air passage. Inserted, the bearing portion in which the correction shaft member is inserted is housed in a molding die, and a cylindrical portion having an air passage,
In addition, the holding portion for holding the bearing portion is integrally formed of a resin material, and after molding, the straightening shaft member is pulled out from the bearing portion into which the straightening shaft member has been inserted, and the shaft is inserted into the bearing portion from which the straightening shaft member is pulled out. Insert and secure the valve member to the shaft. The straightening shaft member is inserted into the bearing portion, and after molding, the straightening shaft member is pulled out of the bearing portion.

As a result, the axis between the bearing portions for holding the shaft is held in a very accurate state. Therefore, the axis of the portion that supports the throttle shaft in the bearing can be surely matched. Furthermore, by forming the cylinder and the holder integrally, there is no need to join the cylinder and the holder as compared with the case where the cylinder and the holder are formed separately, and the manufacturing process of the throttle body can be reduced. Therefore, the production is easy and the production cost can be reduced.

According to the method for manufacturing the throttle body for an engine according to the second aspect of the present invention, since the bearing portion has the bearing, the effect of preventing the valve member from sticking due to icing or adhesion of the deposit can be prevented as compared with the sliding bearing. Can be increased. Further, in the step of forming the cylindrical portion and the holding portion, by covering the axial end portion of the bearing with the covering member, it is possible to prevent the resin material from flowing into the rotating portion of the bearing and to prevent the bearing from rotating poorly. Can be prevented.

According to the method for manufacturing an engine throttle body according to the third aspect of the present invention, since the covering member has the peripheral wall covering the circumferential side portion of the bearing, the resin material flows into the rotating portion of the bearing during molding. This can reliably prevent the occurrence of rotation failure in the bearing. Furthermore, since the rotation preventing means for preventing the bearing from rotating is provided on the peripheral wall, it is possible to prevent the bearing from rotating in the resin at the time of molding, and to prevent the bearing from moving in the shaft thrust direction.

According to the method for manufacturing an engine throttle body of the present invention, the outer diameter of the shaft is smaller than the outer diameter of the portion accommodated in the cylindrical portion. Poor rotation of the shaft due to contact between the shaft and the tubular portion can be prevented. Therefore, it is possible to improve the control of the opening degree of the air passage by the valve member and to appropriately adjust the air flow rate in the air passage.

According to the method for manufacturing a throttle body for an engine according to the fifth aspect of the present invention, when the correction shaft member is pulled out of the bearing portion after molding, the correction shaft member is pulled out in one predetermined direction. The end of the holding portion in the direction opposite to the predetermined one direction can be sealed. For this reason, since a rotating part such as a shaft is not exposed to the outside, airtightness and liquid tightness with the outside can be improved, and there is no need to attach a special waterproof plug or the like. Therefore, the number of parts can be reduced with a simple configuration, and the manufacturing cost can be reduced.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (First Embodiment) FIG. 2 shows a throttle body for an engine according to a first embodiment of the present invention. The throttle body 10 shown in FIG. 2 is attached to the inlet side of a surge tank (not shown) provided in the intake system of the engine. The throttle body 10 includes a housing 11, a throttle shaft 13 as a shaft, and a throttle valve 14 as a valve member. The housing 11 includes a cylindrical portion 20 and holding portions 31 and 32, and is integrally formed by resin molding using a molding die.

The cylindrical portion 20 has a simple cylindrical shape without any irregularities, and has an intake passage 12 formed therein. The throttle valve 14 for adjusting the opening degree of the intake passage 12 is provided with a screw 1.
5, the throttle shaft 13 is fixed to the throttle body 10
Is rotatably supported. Through holes 21 and 22 through which the throttle shaft 13 is inserted are formed at positions corresponding to the holding portions 31 and 32 of the cylindrical portion 20. The cylindrical portion 20 is
In order to control the clearance formed with the throttle valve 14 with high precision, the roundness and the inner diameter are formed with high precision.

The throttle shaft 13 has a first large diameter portion 16, a small diameter portion 17, and a second large diameter portion 18. The first large diameter portion 16 is provided at one end of the throttle shaft 13,
It is supported by a bearing 41 described later. Small diameter part 17
Is connected to the first large diameter portion 16 and the second large diameter portion 18, and fixes the throttle valve 14 with screws 15. Second
The large diameter portion 18 is connected to the small diameter portion 17 and a lever 19 described later, and is supported by a bearing portion 42 described later. The first large diameter portion 16 and the second large diameter portion 18 have substantially the same outer diameter, and the small diameter portion 17 has the smallest outer diameter. That is, in the throttle shaft 13, the outer diameter of the portion accommodated in the cylindrical portion 20 is smaller than the outer diameter of the portion accommodated in the holding portions 31 and 32. The lever 19 connected to the second large diameter portion 18 is provided at the other end of the throttle shaft 13 and is connected to the other end of a cable (not shown) having one end connected to an accelerator pedal (not shown).

The holding portions 31 and 32 project radially outward from the cylindrical portion 20, and through holes 33 and 34 for holding bearing portions 41 and 42 for supporting the throttle shaft 13 are formed in the through holes 21 and 22. It is formed penetrating the holding parts 31 and 32 so as to communicate with each other. The bearing portion 41 is a slide bearing, which is held on the inner wall of the through hole 33 and rotatably supports the first large diameter portion 16 of the throttle shaft 13. The bearing portion 42 is a bearing having a bearing 44 such as a ball bearing or a needle bearing. The bearing portion 42 is held on the inner wall of the through hole 34 and rotatably supports the second large diameter portion 18 of the throttle shaft 13.

Next, a method of manufacturing the throttle body 10 will be described with reference to FIGS. (1) As shown in FIG. 1, at the time of molding the housing 11, after the correction pins 50 are inserted into the bearing portions 41 and 42, these are housed in the resin molding die 100, or the bearing portions 41 and 42 are After being accommodated in the mold 100, the straightening pin 50 is inserted into the bearing portions 41 and 42. Then, the cylindrical portion 20 and the holding portions 31 and 32 are integrally formed. Here, the straightening pin 50 as a straightening shaft member is connected to the first large diameter portion 16 of the throttle shaft 13 shown in FIG.
It has an outer diameter substantially the same as that of the large diameter portion 18 substantially uniformly over the entire length in the axial direction. Therefore, the outer diameter of the correction pin 50 is larger than the outer diameter of the small diameter portion 17 of the throttle shaft 13. (2) After molding, straightening pins 50 are inserted from bearings 41 and 42.
And press-fit an oil seal (not shown) into the holding portions 31 and 32.

(3) As shown in FIG.
Are inserted into the through holes 21 and 22 so that the first large diameter portion 16 and the second large diameter portion 18 of the throttle shaft 13 are supported by the bearing portions 41 and 42. Then, the throttle valve 14 is sandwiched between the throttle shafts 13 and fixed with screws 15.

Next, the operation of the throttle body 10 manufactured in the above steps (1) to (3) will be described. When the accelerator pedal is depressed, the cable moves by an amount corresponding to the amount of depression of the accelerator pedal, and the lever 19 and the throttle shaft 13 are rotationally driven by an amount corresponding to the amount of movement of the cable, The throttle valve 14 rotates by an angle equal to this rotation angle. The amount of intake air according to the opening of the throttle valve 14 passes through the intake passage 12 and is sucked into the cylinder by the pumping action of the engine piston.

At this time, the throttle shaft 13 is
Since the outer diameter of the portion accommodated in the holding portion 31 and 32 is smaller than the outer diameter of the portion accommodated in the holding portions 31 and 32, the throttle shaft 13
Rotation failure of the throttle shaft 13 due to contact between the housing 11 and the resin housing 11 can be prevented. Therefore,
The control of the opening degree of the intake passage 12 by the throttle valve 14 is improved, and the air flow rate in the intake passage 12 can be adjusted favorably. Further, since the bearing portion 42 has the bearing 44, the effect of preventing the throttle valve 14 from sticking due to icing or deposit adhesion can be enhanced as compared with the case where both the bearing portions 41 and 42 are formed as sliding bearings. .

In the first embodiment of the present invention described above, the straightening pin 50 is inserted into the bearing portions 41 and 42,
The cylindrical portion 20 and the holding portions 31 and 32 are integrally formed of a resin material. After the shaping, the straightening pin 50 is pulled out from the bearing portions 41 and 42, and the throttle shaft 13 is inserted into the bearing portions 41 and 42. Throttle valve 14
Is fixed.

By performing resin molding while holding the bearing portions 41 and 42 on the straightening pin 50, the shaft centers of the bearing portions 41 and 42 holding the throttle shaft 13 are aligned accurately. Thus, the bearing portions 41 and 42 are held by the holding portions 31 and 32, respectively.

Therefore, both ends of the throttle shaft 13 are
The axis of the portion supported at the location can be accurately aligned. For this reason, for example, the two bearing portions 41, 4
2. It is possible to suppress an increase in the rotation torque of the throttle shaft 13 that occurs when the throttle shaft 13 is inserted in a state where the shaft 2 is displaced, and to give an extra drive loss to a motor or the like that drives the throttle shaft 13. Can be prevented. Further, in the first embodiment, the cylindrical portion 20 and the holding portion 3
By integrally molding 1 and 32, there is no need to join the cylindrical portion 20 and the holding portions 31 and 32 as compared with the case where they are molded separately, and the manufacturing process of the throttle body 10 can be reduced. Therefore, the production is easy and the production cost can be reduced.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
And FIG. In the second embodiment, the axial end and the circumferential side surface of the bearing 44 of the first embodiment shown in FIG. 1 are covered with a covering member, and the same components as those of the first embodiment are denoted by the same reference numerals. . In the second embodiment, as shown in FIG. 3, when molding the housing 11, the axial end and the circumferential side of the bearing 44 are covered with a collar 60, and the correction pin 50 is inserted into the bearing 42 and the collar 60. Then, the housing 11 is formed integrally. Here, as shown in FIG.
1 and a peripheral wall 62. The side wall 61 has a hole 65, and the inner diameter of the hole 65 is
Or slightly larger than the outer diameter of the straightening pin 50. Therefore, the side wall 61 can cover the axial end of the bearing 44. The peripheral wall 62 has a groove 63 on the outer surface, and is subjected to a non-slip process such as a so-called knurl process. The anti-slip processing prevents the bearing 44 from rotating in the resin during molding. That is, the collar 60 has a rotation preventing means. Further, the peripheral wall 62 can cover a peripheral side portion of the bearing 44. After molding, an engine throttle body is manufactured by the same steps as steps (2) and (3) of the first embodiment.

In the second embodiment, the axial end of the bearing 44 is covered by the side wall 61 of the collar 60 during molding, so that the resin material is prevented from flowing into the rotating portion of the bearing 44, and The occurrence of poor rotation can be prevented.

Further, in the second embodiment, the color 60
Since the peripheral wall 62 covers the circumferential side of the bearing 44, it reliably prevents the resin material from flowing into the rotating portion of the bearing 44 during molding, thereby reliably preventing the rotation failure of the bearing 44. be able to. Furthermore, in the second embodiment, since the peripheral wall 62 of the collar 60 is subjected to anti-slip processing, the bearing 44 is prevented from rotating in the resin during molding, and the bearing 44 is prevented from rotating in the shaft thrust direction. Movement can be prevented.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
Shown in In the third embodiment, the collar 60 of the second embodiment shown in FIG. 3 is formed so as to cover only the axial end of the bearing 44, and the same components as those of the second embodiment are denoted by the same reference numerals. In the third embodiment, as shown in FIG. 4, when molding the housing 11, the axial end of the bearing 44 is covered with a collar 70, and the correction pin 50 is attached to the bearing 42.
Then, the housing 11 is integrally formed by inserting the gate into the opposite side of the collar 70 from the bearing 70. At this time, the molding pressure causes the collar 70 to
4, so that the resin material can be prevented from flowing into the rotating portion of the bearing 44. Here, the collar 70 as a covering member has a disk shape having a hole 75. The inner diameter of the hole 75 is equal to or slightly larger than the outer diameter of the straightening pin 50. Also in the third embodiment, the bearing 4 is formed at the time of molding.
By covering the end of the bearing 4 in the axial direction with the collar 70, it is possible to prevent the resin material from flowing into the rotating part of the bearing 44, and to prevent the bearing 44 from rotating poorly.

(Fourth Embodiment) FIG. 6 shows a fourth embodiment of the present invention.
And FIG. In the fourth embodiment, the end of the holding portion 31 of the first embodiment shown in FIGS. 1 and 2 is sealed, and the same components as those in the first embodiment are denoted by the same reference numerals. In the fourth embodiment, as shown in FIG. 7, the holding portion 131 is formed such that a hole 133 for holding a bearing portion 41 that supports the throttle shaft 13 communicates with the through hole 21. The end of the hole 133 on the side opposite to the through-hole is sealed by the sealing portion 45.

As shown in FIG. 6, when molding the housing 111, the correction pins 50 are inserted into the bearing portions 41 and 42, and then these are housed in the resin molding die 200 or the bearing portions 41 and 42 are After being accommodated in the mold 200, the straightening pin 50 is inserted into the bearing portions 41 and 42. Then, the cylindrical portion 20 and the holding portions 131 and 32 are integrally formed. After the molding, the straightening pin 50 is pulled out from the bearings 41 and 42 in the rightward direction in FIG. 6, that is, in one predetermined direction, and an oil seal (not shown) is pressed into the holding portion 32. After that, the throttle body 110 for the engine is manufactured by a process similar to the process (3) of the first embodiment.

In the fourth embodiment, the end of the holding portion 131 can be sealed by the sealing portion 45 by pulling out the straightening pin 50 from the bearing portions 41 and 42 in one predetermined direction after molding. . Therefore, the throttle shaft 13
Since the rotating parts such as are not exposed to the outside, airtightness and liquid tightness with the outside can be enhanced, and it is not necessary to attach a special waterproof plug or the like. Therefore, the number of parts can be reduced with a simple configuration, and the manufacturing cost can be reduced.

In the first and fourth embodiments of the present invention described above, a sliding bearing is employed for the bearing 41 and a bearing is employed for the bearing 42. However, in the present invention, the sliding bearings are provided for both bearings. Alternatively, a bearing may be employed. Further, in the first and fourth embodiments of the present invention, the throttle shaft 13 has a stepped shape having the first large diameter portion 16, the small diameter portion 17, and the second large diameter portion 18. May have a shape having a substantially uniform outer diameter over the entire length in the axial direction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a method of manufacturing a throttle body according to a first embodiment of the present invention and illustrating a state when a housing is formed.

FIG. 2 is a sectional view showing a throttle body according to a first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part illustrating a method of manufacturing a throttle body according to a second embodiment of the present invention and illustrating a state when a housing is formed.

FIG. 4 is a perspective view showing a collar according to a second embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view of a main part illustrating a method of manufacturing a throttle body according to a third embodiment of the present invention, illustrating a state when a housing is formed.

FIG. 6 is a cross-sectional view illustrating a method of manufacturing a throttle body according to a fourth embodiment of the present invention, illustrating a state when a housing is formed.

FIG. 7 is a sectional view showing a throttle body according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference numerals 10, 110 Throttle body 11, 111 Housing 12 Intake passage (air passage) 13 Throttle shaft (shaft) 14 Throttle valve (valve member) 20 Cylindrical portion 31, 32, 131 Holding portion 41, 42 Bearing portion 44 Bearing 45 Sealing portion 50 Straightening Pin (Shaft Member for Straightening) 60, 70 Collar (Coating Member) 61 Side Wall 62 Peripheral Wall 100, 200 Resin Mold

Claims (5)

[Claims] 1. A method of manufacturing a throttle body for an internal combustion engine for adjusting an air flow rate of an air passage formed therein, comprising: a straightening portion provided on a bearing portion of a shaft for fixing a valve member for controlling an opening degree of the air passage. And a step of inserting the correction shaft member, the bearing portion in which the correction shaft member is inserted is housed in a molding die, and a cylindrical portion having an air passage, and a holding portion holding the bearing portion are integrally formed of a resin material. Molding, after molding, withdrawing the straightening shaft member from the bearing portion into which the straightening shaft member has been inserted, and inserting the shaft into the bearing portion from which the straightening shaft member has been pulled out. Fixing the valve member to the shaft. A method for manufacturing a throttle body for an internal combustion engine, comprising: 2. The method for manufacturing a throttle body for an internal combustion engine according to claim 1, wherein the bearing has a bearing, and in the forming step, an axial end of the bearing is covered with a covering member. . 3. The bearing according to claim 2, wherein the covering member has a peripheral wall that covers a peripheral side portion of the bearing, and rotation preventing means provided on the peripheral wall to prevent rotation of the bearing. A method for manufacturing a throttle body for an internal combustion engine. 4. The internal combustion engine according to claim 1, wherein the shaft has an outer diameter of a portion accommodated in the cylindrical portion smaller than an outer diameter of a portion accommodated in the holding portion. Manufacturing method of throttle body for engine. 5. The method for manufacturing a throttle body for an internal combustion engine according to claim 1, wherein in the step of pulling out the correction shaft member, the correction shaft member is pulled out in one predetermined direction.