GB2391907A

GB2391907A - Shaft bearing arrangement in a variable air intake system for i.c. engines

Info

Publication number: GB2391907A
Application number: GB0316686A
Authority: GB
Inventors: Masao Ino; Tetsuji Yamanaka; Takashi Chaya; Toshio Hayashi
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2002-07-29
Filing date: 2003-07-16
Publication date: 2004-02-18
Anticipated expiration: 2023-07-16
Also published as: GB0316686D0; GB2391907B; JP2004060525A

Abstract

Valve members 30 for respective intake passages 131-134 are mounted on a shaft 40 driven by an actuator 60-62 and held in an end bearing 51 and intermediate bearings 52 in the intake manifold 10. The intermediate bearings may be integral with the manifold 10. The far end of the shaft 40 from the actuator 60 has a cover portion 42 that rotates in sliding contact with an end bearing member 51, eg made of a metal such as aluminium or iron, so that the bearing has high accuracy of form and the clearance between the cover portion 42 and the end bearing member 51 can be made smaller than the clearance at the intermediate bearings 52. Any deviation between axes of the cover portion 42 and the end bearing member 51 may be absorbed by an elastic bush 53 disposed between the end bearing member 51 and the intake manifold 10. Since the cover 42 and the end bearing member 51 are made of different materials, a marginal FV value is increased, and abrasion is reduced. It is stated that the end bearing or intermediate bearings may be roller bearings.

Description

VARIABLE AIR INTAKE SYSTEM

The present invention relates to a variable air intake system in particular, although not exclusively, of an 5 internal combustion engine Conventionally, a variable air intake system for improving engine torque by variably setting length of an intake air passage in accordance with a rotation speed of an internal combustion engine has been proposed. When the 10 rotation speed of the engine is low, the intake air passage is lengthened. When the rotation speed of the engine is high, the intake air passage is shortened. Thus, the torque is improved regardless of the rotation speed of the engine.

In such a variable air intake system, for instance, 15 branched intake air passages having different passage lengths are formed. Thus, a total length and a cross-sectional area of the intake passage are changed by opening or closing the branched intake passages with valve members respectively. As an example of the valve member for opening and closing the 20 intake air passage of the variable air intake system, a butterfly valve disclosed in DE29916333U1 is publicly known.

As shown in Fig. 3, a prior art intake manifold 100 branches in

accordance with a number of cylinders of an engine, providing intake air passages 101-104. Valve members 105 are disposed 25 respectively in the branching intake air passages 101-104.

The valve member 105 rotates around a driving shaft member 106 The driving shaft member 106 is constituted with a shaft 107

and a cover 108 covering an outer periphery of the shaft 107.

An end of the driving shaft member 106 on an actuator 109 side is rotatably held by a bearing 110, for instance. Thus, the driving shaft member 106 is rotatably held by the intake 5 manifold 100.

Lately, in view of weight reduction and improvement of thermal insulation and designing flexibility, polyamide resins are widely used as materials of parts constituting the air intake system such as the intake manifold 100 and the cover 10 108 of the driving shaft member 106, instead of metals.

However, in the case where resins are used, accuracy of form is decreased in comparison with the case where metals are used. Therefore, if a clearance provided between the driving shaft member 106 and the bearing part 111 of the 15 intake manifold 100 is made small, the driving shaft member 106 and a bearing part 111 of the intake manifold 100 may contact each other, increasing sliding resistance. In order to inhibit an increase in the sliding resistance, a large clearance should be provided between the driving shaft member 20 106 and the intake manifold 100. As a result, an end of the driving shaft member 106 opposite from the actuator, that is, an end on the intake air passage 101 side, becomes a free end, whose motion is not restricted by the bearing part 111.

Intake air passing through the intake air passages 101 25 104 pulsates due to the rotation of the engine. Therefore, the valve members 105 disposed in the intake air passages 101 104 vibrate due to the pulsation. Specifically, if the valve -2-

member 105 on the intake passage 101 side, which provides the free end, is applied with intake air pressure caused by the pulsation, the end of the driving shaft member 106 opposite from the actuator will vibrate greatly. As a result, 5 collision velocity between the driving shaft member 106 and the intake manifold 100 bearing the driving shaft member 106 may increase.

An outer periphery of the driving shaft member 106 is covered by covers 108 made of a resin. Therefore, in the end 10 of the driving shaft part 106 opposite from the actuator, the cover 108 made of the resin contacts the bearing part 111, which is made of a resin, of the intake manifold 100. At a part where members made of resins contact each other, a marginal PV value representing a sliding ability is low.

15 Therefore, abrasion will progress between the driving shaft member 106 and the bearing part 111. If the abrasion progresses, the clearance provided between the driving shaft member 106 and the bearing part 111 will be enlarged. As a result, swinging of the driving shaft member 106 due to the 20 vibration will be enlarged, and the collision velocity between the driving shaft member 106 and the bearing part 111 will increase further, generating abnormal noise.

It is therefore an object of the present invention to provide a variable air intake system capable of preventing 25 vibration and abnormal noise by reducing abrasion.

According to an aspect of the present invention, in a variable air intake system, a clearance formed between an end -3-

bearing member and a driving shaft member is smaller than another clearance formed between an intermediate bearing member and the driving shaft member. Therefore, swinging at a portion of the driving shaft member opposite from an actuator 5 is reduced. Thus, even in the case in which a valve member, specifically a valve member disposed far from the actuator, vibrates due to pulsation of intake air, collision between the driving shaft member and the end bearing member is alleviated.

Thus, abrasion of the driving shaft member and the end bearing 10 member is reduced. Therefore, vibration due to the swinging of the driving shaft member and generation of abnormal noise due to the collision between the driving shaft member and the end bearing member can be prevented.

According to another aspect of the present invention, 15 materials of the driving shaft member and the end bearing member of the variable air intake system are different from each other. Thus, the abrasion of the driving shaft member and the end bearing member is reduced by selecting the material of the end bearing member so that a marginal PV value 20 is increased, in accordance with the material of the driving shaft member. Thus, the vibration due to the swinging of the driving shaft member and the generation of the abnormal noise due to the collision between the driving shaft member and the end bearing member can be prevented. In addition to the end 25 bearing member, the intermediate bearing member may be made of a material different from that of the driving shaft member.

According to another aspect of the present invention, in

the variable air intake system, a portion of the driving shaft member where the driving shaft member is held by the end bearing member is made of a resin. On the other hand, the end bearing member is made of a metal. Therefore, a marginal PV 5 value between the driving shaft member and the end bearing member is increased and the abrasion of the driving shaft member and the end bearing member is inhibited. Therefore, the vibration due to the swinging of the driving shaft member and the generation of the abnormal noise due to the collision 10 between the driving shaft member and the end bearing member can be prevented. Since the end bearing member is made of the metal, an accuracy of form of the end bearing member is improved. Therefore, the clearance formed between the driving shaft member and the end bearing member is lessened.

15 According to yet another aspect of the present invention, an elastic member is disposed between the end bearing member and the intake manifold of the variable air intake system. By disposing the elastic member, even in the case where the clearance between the driving shaft member and the end bearing 20 member is lessened, deviation between the axes of the driving shaft member and the end bearing member is absorbed.

Therefore, sliding resistance between the driving shaft member and the end bearing member is reduced and the abrasion of the driving shaft member and the end bearing member is reduced.

25 As a result, the swing due to the vibration of the driving shaft member and the generation of the abnormal noise due to the collision between the driving shaft member and the end -5-

bearing member can be prevented. In addition, by disposing the elastic member, the vibration of the driving shaft member can be absorbed.

5 Features and advantages of an embodiment will be appreciated, as well as methods of operation and the function of the related parts, from a study of the following detailed description, the appended claims, and the drawings, all of

which form a part of this application. In the drawings: 10 Fig. 1 is a cross-sectional view showing a variable air intake system according to an embodiment of the present invention; Fig. 2 is a cross-sectional view showing an engine having the variable air intake system according to the 15 embodiment; and Fig. 3 is a cross-sectional view showing a prior art

conventional variable air intake system.

Referring to Fig. 2, a variable air intake system 20 according to an embodiment of the present invention is illustrated. The variable air intake system according to the embodiment is disposed in an intake system of an engine. As shown in Fig. 2, the air intake system 1 has an intake manifold 10. The intake manifold 10 connects an air connector 25 11 and cylinders of an engine main body 20.

Intake air drawn through an intake duct (not shown) flows into the air connector 11 through an air cleaner and a -6

throttle valve (not shown) and is divided into intake passages provided by the intake manifold 10 via a surge tank 10a. The intake manifold 10 is divided in accordance with a number of the cylinders of the engine main body 20 from the surge tank 5 10a on an outlet side of the air connector 11 connected with the throttle valve. The intake manifold 10 is formed in the form of a single piece with a polyamide resin.

A total length of an intake passage 12 for low rotation speed to the engine main body 20 is formed to be greater than 10 that of an intake passage 13 for high rotation speed. The divided low rotation speed intake passage 12 and the high rotation speed intake passage 13 are integrated in a downstream portion of the intake manifold 10 along the intake air flow, that is, at the engine main body 20 side. A valve 15 member 30 for changing a cross-sectional area of the intake passage 13 by opening or closing the intake passage 13 is disposed in the high rotation speed intake passage 13. When the valve member 30 blocks the intake passage 13, the intake air is supplied to the engine main body 20 through the low 20 rotation speed intake passage 12. On the other hand, when the valve member 30 opens the intake passage 13, the intake air is supplied to the engine main body 20 through the high rotation speed intake passage 13, which provides a relatively low flow resistance. More specifically, by changing the cross 25 sectional area of the intake passage 13, the flow rate of the intake air passing through the intake passage 13 is changed and the total length of the intake passage through which the -7-

intake air passes is changed.

As shown in Fig. 1, the high rotation speed intake passage 13 is divided in accordance with a number of cylinders of the engine main body 20. The valve members 30 are disposed 5 in respective intake passages 131-134. The valve member 30 can rotate around a driving shaft member 40. The driving shaft member 40 is constituted with a shaft 41 and covers 42 covering the shaft 41. The shaft 41 is made of a metal such as iron and has a cross section in the shape of a polygon. If 10 the intake manifold 10 directly holds the shaft 41 having a cross section in the shape of a polygon, the shaft 41 cannot rotate smoothly. Therefore, the shaft 41 is covered by the covers 42 having a cylindrical periphery, and is held by the intake manifold 10 through the covers 42.

15 The shaft 41 penetrates the valve members 30. Each valve member 30 is made of a polyamide resin and is integrated with the cover 42. The valve member 30 and the cover 42 are formed with a shaft hole 43, which the shaft 41 penetrates.

The cross section of the shaft hole 43 is formed in generally 20 the same shape as the cross section of the shaft 41, which is formed in the shape of a polygon. Therefore, when the shaft 41 is inserted into the shaft hole 43, relative movement among the shaft 41, the valve member 30 and the cover 42 is restricted. 25 The driving shaft member 40 is rotatably held by the intake manifold 10 through a bearing member. The bearing member includes an end bearing member 51 for holding an end of -8-

the driving shaft member 40 on a side opposite from an actuator 60, which drives the valve members 30 through the shaft 41. The bearing member also includes intermediate bearing members 52 for holding the driving shaft member 40 5 between the actuator 60 and the end bearing member 51.

In the embodiment, the intermediate bearing member 52 is formed separately from the intake manifold 10. Alternatively, the intermediate bearing member 52 may be integrated with the intake manifold 10, that is, the intake manifold 10 by itself 10 may provide the intermediate bearing member 52. The intermediate bearing member 52 is made of a polyamide resin, for instance. The intermediate bearing member 52 holds the driving shaft member 40 to the intake manifold 10 rotatably.

Swinging degree of the driving shaft member 4Q due to intake 15 pulsation is smaller at an intermediate part of the driving shaft member 40 than at the end on the intake passage 131 side Therefore, it is not required to reduce the size of the clearance formed between the outer periphery of the cover 42 of the driving shaft member 40 and the inner periphery of the 20 intermediate bearing member 52. Therefore, the intermediate bearing member 52 can be formed even if it is made of a resin with a low accuracy of form.

At another end of the driving shaft member 40 opposite from the end bearing member 51, the actuator 60 for driving 25 the valve members 30 is disposed. The actuator 60 includes a housing 61 made of a polyamide resin and a motor 62. The motor 62 is connected with an ECU (not shown). The ECU _9_

provides intermittent power supply to the motor 62 in order to control the drive of the valve members 30. Driving force of the motor 62 is transmitted to the shaft 41 through a driving gear 63 disposed on the end of the shaft 41 opposite from a 5 bush. The driving gear 63 includes a tooth part 64 and a cylinder part 65. The tooth part 64 and the cylinder part 65 are integrally made of a polyamide resin, for instance. The tooth part 64 can mesh with a pinion (not shown), which is 10 attached to the motor 62. The cylinder part 65 is formed so that the cylinder part 65 protrudes toward the intake manifold 10 side from the tooth part 64. The cylinder part 65 is formed with an insertion hole 66 on its inner periphery, to which the shaft 41 is inserted. The insertion hole 66 is 15 formed generally in the same shape as the cross section of the shaft 41, which is formed in the shape of a polygon. Thus, relative movement between the driving gear 63 and the shaft 41 is restricted. A bearing 67 is disposed between the driving gear 63 and the intake manifold 10. The bearing 67 holds the 20 shaft 41 through the driving gear 63. Thus, the bearing 67 holds the end of the driving shaft member 40 on the actuator 60 side to the intake manifold 10 through the driving gear 63.

Next, the end of the driving shaft member 40 opposite from the actuator 60 will be explained in detail.

25 The end bearing member 51 is formed with a metal such as aluminum or iron in the shape of a ring. An elastic bush 53 as an elastic member is disposed between the end bearing -10

member 51 and the intake manifold 10. The end bearing member 51 is made of a metal. Therefore, in the driving shaft member 40, the cover 42 held by the end bearing member 51 is made of a material different from the material of the end bearing 5 member 51. More specifically, the cover 42 is made of a resin, and the end bearing member 51 is made of a metal. Therefore, a marginal PV value between the cover 42 of the driving shaft member 40 and the end bearing 51 is improved, and abrasion is reduced. In addition, since the end bearing member 51 is made 10 of a metal, the accuracy of form of the end bearing member 51 is improved. Therefore, a clearance formed between the outer periphery of the cover 42 of the driving shaft member 40 and the inner periphery of the end bearing member 51 can be reduced. As a result, the clearance formed between the cover 15 42 of the driving shaft member 40 and the end bearing member 51 can be made smaller than the clearance formed between the cover 42 of the driving shaft member 40 and the intermediate bearing member 52.

The elastic bush 53 is made of a material having elasticity, 20 such as rubber. By disposing the elastic bush 53 between the end bearing member 51 and the intake manifold 10, deviation between axes of the driving shaft member 40 and the end bearing member 51 is absorbed by the elastic bush 53. As explained above, in the case where the end bearing member 51 25 is made of a metal and the clearance between the driving shaft member 40 and the end bearing member 51 is reduced, sliding resistance between the driving shaft member 40 and the end -11-

bearing member 51 will increase if a coaxiality between the driving shaft member 40 and the end bearing member 51 is low.

Therefore, the deviation between the driving shaft member 40 and the end bearing member 51 is absorbed by the elastic bush 5 53, so that the coaxiality between the driving shaft member 40 and the end bearing member 51 is improved and the sliding resistance is reduced. If the driving shaft member 40 vibrates due to the pulsation of the intake air passing through the intake passages 131-134, the elastic bush 53 10 absorbs the vibration of the driving shaft member 40. Thus, the shock due to the collision between the driving shaft member 40 and the end bearing member 51 is alleviated.

As explained above, in the embodiment, the end of the driving shaft member 40 opposite from the actuator 60 is held 15 by the end bearing member 51 made of a metal. Therefore, the clearance formed between the driving shaft member 40 and the end bearing member 51 is reduced and the vibration of the driving shaft member 40 due to the intake pulsation is reduced Therefore, generation of abnormal noise due to the collision 20 between the driving shaft member 40 and the end bearing member 51 can be prevented. Since the cover 42 and the end bearing member 51, which contact each other at the part of the driving shaft member 40 opposite from the actuator, are made of different materials, the marginal PV value is increased.

25 Therefore, the abrasion of the driving shaft member 40 and the end bearing member 51 can be reduced.

In the embodiment, the elastic bush 53 is disposed -12

between the end bearing member 51 and the intake manifold 10.

Therefore, even in the case where the clearance between the driving shaft member 40 and the end bearing member 51 is reduced, the deviation between the axes of the driving shaft 5 - member 40 and the end bearing member 51 is absorbed by the elastic bush 53. Therefore, the increase in the sliding resistance between the driving shaft member 40 and the end bearing member 51 can be inhibited. In addition, the elastic bush 53 absorbs the shock generated in the collision between 10 the driving shaft member 40 and the end bearing member 51.

Therefore, the abrasion between the driving shaft member 40 and the end bearing member 51 can be reduced.

In the embodiment, an example in which only the end bearing member for holding the end of the driving shaft member 15 opposite from the actuator is made of a material different from the material of the driving shaft member is explained.

Alternatively, in addition to the end bearing member, the intermediate bearing members may be made of a metal like the end bearing member and may be disposed in the intake manifold 20 through elastic members. In the embodiment, the case in which the end bearing member is formed in the shape of a ring is explained. Alternatively, as the end bearing member or the intermediate bearing member, a ball bearing or the like may be employed. 25 The present invention should not be limited to the disclosed embodiment, but may be implemented in many other ways without departing from the spirit of the invention.

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Claims

1. A variable air intake system including an intake manifold providing an intake air passage, a valve member, which rotates around a driving shaft member and changes a croes-sectional area of the intake air passage, an actuator for driving the valve member, an end bearing member for holding the driving shaft member to the intake manifold at an end of the driving shaft member opposite from the actuator, and an intermediate bearing member for holding the driving shaft member to the intake manifold at a position between the actuator and the end bearing member, -

the end bearing member and the driving shaft member providing a smaller clearance therebetween than another clearance provided between the intermediate bearing member and the driving shaft member.

2. A variable air intake system as in claim 1, wherein the driving shaft member is made of a material different from that of the end bearing member.

3. A variable air intake system as in claim 2, wherein I- the driving shaft member is made of a material different from that of the intermediate bearing member.

4. A variable air intake system as in claim 2 or 3, wherein I -14

the driving shaft member has a portion made of a resin, at which the driving shaft member is held by the end bearing member, and the end bearing member is made of a metal.

5. A variable air intake system as in any one of claims 1 to 4, comprising Ian elastic member disposed between the end bearing member and the intake manifold.

6. A variable air intake system as in claim 2 or 3, wherein the driving shaft member has a portion made of a resin, at which the driving shaft member is held by the intermediate bearing member, and the intermediate bearing member is made of a metal.

7. A variable air intake system as in any one of claims 1, 2, 3 and 6, comprising I I an elastic member disposed between the intermediate bearing member and the intake manifold.

8. A variable air intake system substantially as described herein and with reference to figures 1 and 2 of the drawings hereof.

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