JPS6024344B2 - Keisink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casing, and more particularly to a casing formed from a light metal material by die casting.

For example, in various devices such as automatic door devices, a variable speed gear mechanism is used as a mechanism to change the rotational output of an appropriate drive source such as an electric motor to an appropriate speed and transmit it to a driven part. .

This transmission gear mechanism generally includes a gear box serving as a casing that rotatably supports a plurality of various gears and a mirror to which these gears are fixed, and also supports the gears. . The ball support of the ball to the gear box forms a mounting portion having a circular inner peripheral surface on the inner wall of the gear box, and a bearing member having a circular outer peripheral surface is attached to the ball, and such a bearing member is attached to the ball. This is accomplished by mounting on the mounting section. Recently, it has been proposed and put into practical use that a casing such as the gear box is formed from a light metal material such as aluminum or an aluminum-based alloy by die casting.

However, in the die-cast state, the bearing member cannot be properly mounted to the mounting portion as required due to the existence of a draft on the circular inner circumferential surface of the mounting portion. Therefore, after die-casting the secondary casing, it is necessary to perform precision machining on the circular inner circumferential surface of the mounting portion, and due to such precision machining, the manufacturing cost of the casing becomes considerably high. Ta. On the other hand, as a structure that can be directly used in the die-cast state without performing precision processing, Jitsuneki No. 50-180653 discloses that the wall on which the mounting part is formed also has a structure inside the circular shape of the mounting part. An opening that matches the circumferential surface is formed, and the so-called draft angle between the entrance and the circular inner circumferential surface of the mounting portion is formed such that the inner diameter gradually decreases from the outer wall surface toward the tip of the mounting portion. It is disclosed that light direction through grooves are formed in a cylindrical wall portion at circumferentially spaced intervals.

In the structure disclosed in Japanese Utility Model Application Publication No. 50-806533, the bearing part is press-fitted into the mounting part from the outer wall side, and at this time, due to the presence of the groove, the cylinder of the mounting part is The shaped wall portion is elastically steered outward, and the bearing member is thus elastically held in the mounting portion. However, the above-mentioned structure disclosed in Japanese Patent Publication No. 50-80653 is also not fully satisfactory; Because of this, the outer circumferential surface of the bearing member is not brought into contact with the circular inner circumferential surface of the mounting part over the entire width in the direction of the flywheel, and the supporting action of the bearing part by the mounting part is only partially supported in the direction of the flywheel. Therefore, the retention of the competitive parts is insufficient,
The vibration of the bearing member and the generation of noise caused by this are observed.'o) Since the bearing member is held using the elastic mirror of the mounting part, the holding strength of the bearing member is also important from this point of view. However, if the two mounting parts are arranged close to each other, the elastic deformation of both parts will interfere with each other, so it is not possible to arrange the two mounting parts close to each other. ,〇It is necessary to provide a plurality of relatively thin flap pieces in the die-casting mold to define the above-mentioned groove, but there is a large risk that such flap pieces will break in a short period of time, etc. There are some shortcomings. The present invention has been made in view of the above facts, and its main purpose is to provide a casing formed from a light metal material by die-casting, without performing precision machining on the mounting part after die-casting. The bearing member can be press-fitted into the mounting part in the as-die-cast state without causing any problems, and in particular, a relatively large force in a predetermined angular direction is applied to the shaft, so that the mounting To provide a new and superior casing that can sufficiently reliably and firmly hold or support a press-fitted bearing member even when a relatively large force is applied locally at a predetermined angular position on the circular inner circumferential surface of the part. It is to be.

According to the present invention, as a casing that achieves the above object, the casing is molded from a light metal material by die-casting, the inner wall surface of which is formed with a mounting portion having a circular inner circumferential surface, and the casing is made of a light metal material by die-casting. In a casing in which a bearing member having a circular outer circumferential surface for rotatably supporting the shaft is press-fitted into the mounting part: a portion of the circular inner circumferential surface of the mounting part having an angular range of approximately 180 degrees or less; A plurality of support protrusions extending in the axial direction are formed at opposite intervals in the circumferential direction, and the protrusion height in all directions of the diameter of the support protrusions is as follows:
There is provided a casing characterized in that the angular range is gradually lowered as it moves away from the center.

A more detailed description will be given below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, a casing formed by die-casting from a suitable light metal material such as aluminum or an aluminum-based alloy has a mounting part on the inner surface of its side wall 2 that is similar to the mounting part in a conventional casing. Similarly, a mounting portion 6 having a circular inner circumferential surface 4 is formed.

On the circular inner circumferential surface 4 of the mounting part 6, lights are arranged at equal intervals in the direction of the wall.
A plurality of (eight in the illustrated case) support protrusions 20 are formed. The radial protrusion heights of these support protrusions 20 are substantially the same. When molding the casing by die-casting, in order to perform die cutting, a draft angle is applied to each of the plurality of support protrusions 20 formed therein as well as the circular inner peripheral surface of the mounting portion 6. However, it is desirable that the draft angle in each of the plurality of support protrusions 20 be generated on both circumferential side surfaces of the support protrusion 20 and not on the inner surface of the support protrusion 20 in the hook direction.

That is, in each of the support protrusions 20, the support protrusions 20 are arranged on both sides of the support protrusion 20 in the width direction so that the width in the circumferential direction of the support protrusion gradually increases from the receiving end (protruding end) to the bottom end (base end) of the mounting portion 6. Although a draft angle is generated on the surface, the support protrusion 20
There is virtually no draft on the inner surface in the radial direction of each of the support protrusions 20, so the diameter ○3 of the circle defined by the inner surface in the radial direction of each of the support protrusions 20 does not vary in the rattan direction and is made uniform. is desirable. In the mounting portion 6 as described above, the inner diameter D of the circular inner circumferential surface 4 is set to be slightly larger than the outer diameter ○2 of the circular outer circumferential surface 12 of the bearing section 14 to be mounted thereon.

On the other hand, the diameter ○3 of the circle defined by the inner surfaces of the plurality of support protrusions 20 in the flea direction is the circular outer circumferential surface 1 of the bearing member 14.
It is set slightly smaller than Gaiyo D2 of No. 2. The projecting height of the plurality of support protrusions 20 in the direction of the hook depends on the inner groove D of the circular inner circumferential surface 4, the outer diameter D2 of the circular outer circumferential surface 12, and the material used for die-casting the casing. Generally speaking, it is about 5/100 to 10/10 magnetic force (in order to clearly illustrate the support protrusion 20, the radial protrusion height of the support protrusion 20 is exaggerated in the drawing). ). In the casing as described above, the ratchet 10 to which a gear (not shown) is fixed is rotatably supported in the mounting portion 6 without any machining after die casting. The bearing part 14 is attached by press fitting such as pressed iron.

In this way, due to the press-fitting of the bearing member 14, the plurality of support protrusions 20 are forcibly deformed so that the diameter D3 is made equal to the outer diameter D2 of the outer peripheral surface of the bearing member 14, and thus the bearing member 14 is mounted in the mounting section 6. Although the casing provided with the mounting portion 6 as described above is fully satisfactory under normal usage conditions, a relatively large force is applied to the shaft 10' in a predetermined angular direction, and therefore When a large force is applied locally to a predetermined angular position on the circular inner circumferential surface of the attachment part, there is a buccal direction that causes the following problem.

That is, a gear (not shown) housed within the casing is brought into engagement with another gear (not shown) also housed within the casing. When two gears are to be engaged with each other, as is well known to those skilled in the art, each gear, and therefore the shaft to which each gear is fixed, and the bearing member that supports the shaft, each have two gears. A force acts in the direction of mutual separation, that is, in the direction of the center of gravity. Therefore, bearing part village 1
4 is press-fitted into the mounting part 6, the mounting part 6 has a specific angular direction (
For example, force is applied from the bearing member 14 to the mounting portion 6 in a concentrated direction (for example, in the direction indicated by an arrow 22 in FIG. 5). Therefore, if the force concentrated in the specific angular direction and acting on the mounting part 6 is quite large, and if there is a support protrusion in and near the specific angular direction, a large force will act on the support protrusion, As a result, the support protrusion is further deformed, causing play in mounting the bearing member, and in some cases, there is a risk that the support protrusion may be damaged. According to the present invention, the following improvements are made in order to solve such problems. Referring to FIG. 3, which shows a specific example of a casing constructed according to the present invention, according to the present invention, the plurality of support protrusions 20' are formed on the circular inner circumferential surface 4 of the mounting portion 6. It is disposed not over the entire circumference, but locally in a portion of the circular inner circumferential surface 4 within an angle range of approximately 180 degrees or less. The protruding height of the plurality of support protrusions 20' is gradually reduced as the distance from the center of the above-mentioned angular range increases. In the casing configured according to the present invention, the circular inner circumferential surface 4 of the mounting portion 6 has an angle range of at least approximately 180 degrees centered on the direction indicated by the arrow 22 corresponding to the scale center direction of the gear. No support protrusions are provided, and the plurality of support protrusions 20' do not support the circular shape of the mounting portion 6 in an angular range of approximately 180 degrees or less centered on the direction opposite to the direction indicated by the arrow 22. It is arranged locally on the inner peripheral surface 4.

In such a second specific example, there is no support protrusion in the direction indicated by the arrow 22 and in the vicinity thereof, and the circular outer circumferential surface of the bearing member is in contact with the circular inner circumferential surface 4 of the mounting portion 6 in such a portion. The above-mentioned force, which comes into direct contact and acts concentratedly in the direction indicated by the arrow 22, is directly transmitted to the circular inner circumferential surface 4 of the mounting portion 6 itself, which has considerably greater strength than the support protrusion. Therefore, even if the force acting concentratedly in the direction of the arrow 22 is considerably large, the bearing member device will not play or the mounting portion will not be damaged.

[Brief explanation of the drawing]

FIG. 1 is a partial front view showing a mounting portion of a casing in which support protrusions are arranged at intervals over the entire circumference of a circular inner circumferential surface of the mounting portion. FIG. 2 is a partial sectional view of the mounting portion shown in FIG. 1. FIG. 3 is a partial front view showing the mounting portion of the casing constructed according to the present invention. 2... Side wall of the casing, 4...
...Circular inner circumferential surface of the mounting part, 6...Circular inner peripheral surface of the mounting part,
14...Bearing member, 20 and 22...
Support protrusion. Figure 1, figure 2, figure 3

Claims (1)

[Claims] 1 A casing formed from a light metal material by die-casting, the inner wall of which is formed with a mounting portion having a circular inner circumferential surface, and a circular outer circumferential surface for rotatably supporting the shaft. In a casing in which a bearing member having a surface is press-fitted into the mounting portion; a portion of the circular inner circumferential surface of the mounting portion having an angular range of approximately 180 degrees or less has an axial line at intervals in the circumferential direction; A casing characterized in that a plurality of support protrusions are formed extending in the angular range, and the height of the radial protrusion of the support protrusions gradually decreases as the distance from the center of the angular range increases.