WO1995016144A1

WO1995016144A1 - Bearing structure

Info

Publication number: WO1995016144A1
Application number: PCT/JP1994/002082
Authority: WO
Inventors: Akira Takahashi; Toru Hashimoto; Mitsuhiro Miyake; Kiyoshi Shinjo; Shigeo Tsukakoshi; Hisakazu Miya; Naoto Nishimoto
Original assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha; Mikuni Corporation; Tokyo Roki Corporation
Priority date: 1993-12-10
Filing date: 1994-12-12
Publication date: 1995-06-15
Also published as: JPH07167141A

Abstract

A bearing structure for radially rotatably supporting a rotating shaft disposed in a valve body serving as a shell unit wherein a truncated cone-shaped fitting hole (25) which has an axis in the same direction as that of the rotating shaft (21a) is provided in the valve body and wherein the rotating shaft is supported by means of a tubular member (23) which has therein an insertion hole (23a) into which the rotating shaft (21a, 31a) is fittingly inserted in such a manner as to freely rotate therein, has an external shape of a truncated cone, and is fittingly inserted into the fitting hole (25). With this bearing structure, it is possible to secure a desired bearing function irrespective of the deformation resulting from expansion and/or contraction of bearing constituent members due to change in ambient temperatures.

Description

Mechano-bearing structure Technical field

The present invention relates to a bearing structure for supporting a rotating shaft of a butterfly valve used for an intake device of an internal combustion engine mounted on, for example, an automobile, and more particularly, to a (radial) bearing structure for supporting the rotating shaft in a radial direction. About.

Background art

For example, as a bearing structure for supporting a rotating shaft of a multiple butterfly valve used in an intake device of an internal combustion engine, there is one as shown in FIG.

As shown in the figure, the valve body 1 of the intake device is provided with a rotary shaft insertion hole 1b penetrating through the intake passages in a direction orthogonal to the six intake passages. In each intake passage, a rotating shaft 2a for firmly supporting the valve body 2 is inserted into the fitting hole 1b from one end of the valve body 1, whereby the rotating shaft 2a is rotatably supported. Structure. In other words, the inner peripheral wall of the fitting hole 1b provided in the valve body 1 itself serves as a bearing, and the inner peripheral wall of the fitting hole 1b has a lubricating metal dry bearing. There is a type that press-fits the bearing and acts as a bearing.

In such a bearing structure, the rotating shaft 2a and the valve It is assumed that the bearings have different clear coefficients due to the difference in thermal expansion coefficient when they are made of different materials such as steel and aluminum, or that they are made of the same material. However, even if the bearing clearance fluctuates due to the difference in the amount of expansion and contraction due to the shape, it is not possible to compensate for such fluctuation in the clearance, and therefore, the rotating shaft 2a has the bearing hole. A rattling sound may be generated in the vehicle, or a sudden state may occur when the rotation resistance of the rotation shaft 2a increases due to the close contact state.

On the other hand, as one of today's automobile development policies, the development of fuel-efficient vehicles by reducing the weight of vehicles or the development of low-cost vehicles by changing the material and simplifying the manufacturing process is being considered.

Therefore, as a part of the intake device, such as the valve body 1 or the rotating shaft 2a of the intake device, which was conventionally formed of a metal material such as aluminum or steel, the use of resin as a part of the study is considered. Have been.

However, if the above-mentioned components constituting the conventional intake device are simply made of resin, the resin material is inferior in mechanical strength, abrasion resistance, heat transfer property, etc. as compared with the metal material. New problems arise, such as a decrease in the molding accuracy of the component parts or a decrease in the assembly accuracy due to variations or the like. In view of the above-described problems of the prior art, the object of the present invention is to reduce the weight of the product and, particularly, to control the ambient temperature and the like. Regardless of the difference in the amount of expansion and contraction deformation of the bearing area due to the change, we will provide a bearing structure that can reliably achieve the original function of the bearing with high accuracy.

Disclosure of the invention

The present invention is a bearing structure for rotatably supporting a rotating shaft disposed in a shell in a radial direction thereof, wherein the shell has an axis in the same direction as the axis of the rotating shaft. A frustum-shaped fitting hole, wherein the rotating shaft has a fitting hole inside for rotatably fitting the fitting hole, and has a truncated cone-shaped outer shape; It is characterized in that it is supported by a fitted cylindrical member.

Further, it is characterized in that it has a regulating member for regulating the movement of the cylindrical member in the axial direction.

According to the bearing structure of the present invention, the rotating shaft is rotatably supported on the shell via the cylindrical member, and the cylindrical member having the outer shape of a truncated cone is formed on the shell. It is formed and fitted into a fitting hole which also has the shape of a truncated cone.

Therefore, if the rotating shaft, the cylindrical member, and the shell body undergo thermal expansion, the cylindrical member moves along the inner surface of the fitting hole, that is, in the axial direction so as to absorb the increase in volume, and The optimal happiness can be maintained without reducing the clarity in the area. That is, by utilizing the wedge action of the cylindrical member having the tapered shape, a predetermined bearing function can be obtained regardless of changes in the ambient temperature. In addition, by providing a restricting member for restricting the movement of the cylindrical member in the horizontal direction, even if the cylindrical member moves due to thermal expansion or the like, the cylindrical member is restricted to a predetermined range, thereby preventing the cylindrical member from falling off.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing a bearing structure of a multiple butterfly valve in a conventional intake device, and FIG. 2 is an external plan view of an intake device employing a bearing structure according to the present invention. FIG. 3 is an external side view of the intake device at the arrow R in FIG. 2, FIG. 4 is an external side view of the intake device at the arrow L in FIG. 2, and FIG. FIG. 6 is a cross-sectional view of the intake device taken along a line BB in FIG. 2, FIG. 6 is a partial cross-sectional view showing a bearing structure according to the present invention, and FIG. It is a minute enlarged sectional view.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment in which the bearing structure of the present invention is applied to a support portion of a multiple butterfly valve provided in an intake device for an internal combustion engine will be described with reference to the drawings.

FIG. 2 shows a plan view of the external appearance of the air intake device, and as shown in the drawing, is made of a combination of resin die-cast products forming three regions I, 11 and 1II. That is, a branch portion (I) connected to the head intake port of the engine, a valve body (11) as a shell housing a multiple butterfly valve serving as an intake switching valve, a surge tank, The cover part (1 1 1) that forms the bypass intake passage is made by injection molding, etc. After that, each is integrally joined by vibration welding or the like on the joining flange surface.

FIG. 3 is a side view of the external appearance of the intake device shown in FIG. 2 as viewed in the direction of arrow R. As shown, a flange portion for mounting a throttle body for adjusting the output of the engine is shown. Along with 10, there is disposed an end bearing 20 that rotatably supports one end of a rotating shaft of the multiple butterfly valve.

FIG. 4 shows an external side view of the intake device shown in FIG. 2 as viewed in the direction of arrow L. As shown in the drawing, the outer surface has one end supported by an end bearing 20. An actuator 30 having a gear mechanism built therein is attached to the other end of the rotary shaft of the continuous butterfly valve.

FIG. 5 is a cross-sectional view taken along a line BB in FIG. 2, and a multiple butterfly valve for opening and closing the intake passage 10 is arranged in this region. As shown in this figure, a multiple butterfly valve arranged in a valve body (Π) as a shell has a valve body 21 and a rotating shaft 21a for supporting the same. It is integrally formed of a material. One end of the rotating shaft 2 la is rotatably supported by the end bearing 20, and the rotating shaft located between the valve bodies 21 is rotatably supported by the intermediate bearing 22. ing.

Further, the other end of the rotating shaft 21a is connected to an actuator for driving the multiple butterfly valve. This actiyue 30 When the worm gear 32 is rotated by a drive source (not shown), the worm wheel 31 that rotates with the worm gear 31 rotates, and the rotating shaft 2 1a that is integrally fixed to the worm wheel 31. Is to rotate. The inner surface of the worm wheel 31 is urged outward by a spring 33, and a flange portion 21b formed integrally with the rotating shaft 21a has a valve body 21b. It is in contact with the inner wall of (Π) and acts as a thrilling good luck.

Here, the connection structure between the rotating shaft 21a and the worm wheel 31 will be described. As shown in FIG. 6, the worm wheel 31 protrudes from the gear portion and has a fitting hole therein. A cylindrical member 31a having 31b is provided, while a fitting shaft 21c is provided at an end of the rotating shaft 21a. Then, the worm wheel 31 is assembled so that the fitting shaft 21c can be fitted and fitted into the fitting hole 31b, so that the two can be firmly and firmly fixed. ing.

Similarly, the other end of the rotating shaft 21a supported by the end bearing 20 and the intermediate $ bearing 22 is also rotatable by the cylindrical member 23 serving as the $ bearing. Supported.

Such a bearing portion is a feature of the present invention, and its structure will be described in detail below.

As shown in FIG. 7, the outer peripheral surface of the cylindrical member 31a of the worm wheel 31 fitted and fixed to the fitting shaft portion 21c of the rotating shaft 2la and the valve body (Π) Circle formed on Similarly, an outer wall surface 23 b having a truncated cone shape is provided between the fitting hole 25 having a truncated frustum shape, and a cylindrical member 31 a serving as a rotation shaft is provided at the center. A cylindrical member 23 having a fitting hole 23 a for fitting is fitted. That is, the rotating shaft (columnar member) is supported by the valve body (Π) via the cylindrical member 23.

Here, since the cylindrical member 23 is fitted into the fitting hole 25 having a truncated cone shape like the outer wall thereof, a wedge action is generated on the fitting surface. That is, due to an increase in the ambient temperature, etc., the fitting hole 25 of the cylindrical member 3 la (rotating shaft), the cylindrical member 23 and the valve body (Π) undergoes expansion deformation. When the amount of expansion deformation of the cylindrical member 31a and the cylindrical member 23 is larger than the amount of expanded deformation, as shown in FIG. The cylindrical member 23 is moved in the direction of arrow S by the contact surface direction component H of the contacting force W. By the movement of the cylindrical member, the outer peripheral surface of the cylindrical member 31 a (rotating shaft) does not engage with the inner wall surface (bearing surface) of the fitting hole 23 a of the cylindrical member 23. The desired euphoria can be obtained by maintaining the clarity.

For example, if the structure is such that the direct rotation is supported by a hole formed in the valve body as in the conventional example, or if a cylindrical member is not a truncated cone but a mere cylinder, No wedge effect occurs, especially when the amount of expansion due to rotation is large. If it is large, the clearance on the Yuuki receiving surface will be small, and it may be difficult to rotate by the rotation $.

On the other hand, in the present invention, by interposing the cylindrical member 23 having a truncated cone shape as described above, it is possible to ensure a predetermined bearing function regardless of the difference in the amount of expansion and contraction deformation of each component. it can.

In addition, as shown in FIG. 7, a restricting member 24 for restricting the movement of the cylindrical member 23 to a predetermined range is disposed so as to abut on one end surface 23 c of the cylindrical member 23. Thus, the tubular member 23 can be prevented from falling out of the fitting hole 25.

Next, a procedure for assembling the bearing will be described. First, after the multiple butterfly valve is arranged and fixed in the valve body by the intermediate bearing 22 or the like, the cylindrical member 23 is fitted into the fitting hole 25 and fitted. At this time, a stopper wall 26 is formed at the tip of the fitting hole 25 so that the other end surface 23 d of the cylindrical member comes into contact with the cylindrical member 23, thereby restricting the amount of fitting of the cylindrical member 23. You may. Then, with the ring-shaped regulating member 24 loosely fitted to the cylindrical member 31 a of the worm wheel 31, the worm wheel 31 is connected and fixed to the rotation $ 2 la. This constitutes a bearing that supports the other end of the rotating shaft of the multiple butterfly valve in the radial direction. Although the above-mentioned regulating members 24 are provided independently of each other, a configuration in which the inner end surface of the worm wheel 31 is used as the regulating portion may be employed. Further, the regulating member 24 is formed using an elastic material to prevent the cylindrical member 23 from rattling due to engine vibration. May be taken.

As described above, according to the bearing structure of the present invention, a frusto-conical fitting hole having an axis in the same direction as the axis of the rotating shaft is formed in the valve body as a shell. Fitted into the fitting hole The rotating shaft is rotatably supported by the fitting hole (bearing hole) provided in the external truncated cone-shaped cylindrical member to be fitted. Even if each member expands and deforms, the cylindrical member having the shape of a truncated cone moves in the axial direction by wedge action, so that a predetermined clearance can always be secured in the bearing region. However, a desired bearing function can be maintained.

In addition, by providing a regulating member for regulating the movement of the cylindrical member in the axial direction, the cylindrical member can be prevented from falling out of the fitting hole, and the desired bearing function can be maintained as described above.

Industrial applicability

As described above, the bearing structure according to the present invention can be used as a radial bearing that supports a rotating shaft that fixes a butterfly valve of an intake device for an internal combustion engine, and that supports other rotating shafts. It is useful for use as a radial bearing that is mounted on a rotating shaft, and is particularly suitable for mounting from the axial direction of the rotating shaft.

Claims

a Range of request

1. A supporting structure for rotatably supporting a rotating shaft disposed in a shell in a radial direction thereof, wherein the shell has a truncated cone shape having an axis in the same direction as the axis of the rotating shaft. The rotating shaft has a fitting hole in which the rotating shaft can be rotatably inserted, and has a truncated conical outer shape, and is fitted into the fitting hole. A bearing structure characterized by being supported by a cylindrical member provided.

2. The bearing structure according to claim 1, further comprising a regulating member for regulating movement of the cylindrical member in the axial direction.