JPS5926124Y2 - Transmission case - Google Patents

Description

[Detailed description of the invention] This invention relates to a transmission case for a vehicle, and is specifically designed to prevent various abnormal noises radiated from the case body into the vehicle interior due to vibrations caused by gear engagement within the case body. It is related to the structure of

Conventionally, when the case body generates vibrations of 800 Hz or more due to the meshing vibrations of the gears, the vibrations are radiated into the vehicle interior as various abnormal noises.

As a countermeasure to this problem, reinforcing the shape of the case body or using ribs may be considered.

However, relying only on the shape of the case body is an insufficient countermeasure, and if rib reinforcement is carelessly implemented, the overall external surface of the case body will become flat due to the ribs, resulting in Strong vibrations are likely to occur.

In view of these conventional circumstances, this idea was created to create a transmission case that suppresses the noise caused by the above radiation by most effectively combining the shape of the case body and reinforcing ribs. The purpose is to provide

Next, the configuration of this invention will be explained in detail according to an embodiment shown in the drawings.

First, to describe the general phenomenon related to the radiated noise of the 1-Lance transmission case, this case picks up the internal gear meshing sound and impact sound, and each surface vibrates in the range of 800Hz to 2000Hz, usually in 4 nodes. vibration modes are likely to occur.

Suppressing this vibration mode reduces the above-mentioned radiated sound.

And the l-rance transmission case is 100Hz~
It is essential to increase the bending rigidity in the vertical direction in order to reduce the abnormal noise usually called "muffled noise" at 200 Hz, and to reduce high-frequency abnormal noise, the cross-sectional area of the case must be increased. The goal is to make it as small as possible.

When these conditions are met, the cross-sectional shape of the case takes on a kind of elliptical shape with narrow upper and lower surfaces and wide left and right sides.

However, even if the cross-sectional shape of the case changes greatly from an elliptical shape to a rectangular shape, the vibration mode of this case hardly changes.

Therefore, in this embodiment, first, each surface of the case body 1 is made curved as a means to suppress the above-mentioned vibration mode.

That is, one side of the case body 1 is largely curved inward to form the recess 2.

In particular, since the vibration level of the right side surface in the cross-sectional view of FIG. 2 is high, the recess 2 is formed on this side surface.

Furthermore, two annular ribs 3 are formed on the outer periphery of the case body 1.

These annular ribs 3 are shaped to emphasize the recess 2 and the bulge on the opposite side.

Furthermore, it is preferable that these annular ribs 3 are set to be parallel to each other as much as possible.

Further, thick ribs 4 are formed on the upper and lower surfaces of the case body 1 so as to increase the bending rigidity in the vertical direction.

These ribs 4 serve as a countermeasure against the "muffled sound" mentioned above.

However, on both side surfaces of the case body 1, two to three ribs 5 which are continuous over both end surfaces of the case body 1 are formed.

These ribs 5 are formed thinner than the ribs 4 described above.

In addition, in order to suppress the basic vibration mode on each surface of the case body 1, each of the ribs 4 and 5 described above is combined with the reinforcing parts 6 at both end edges of the case body 1. The width of the groove is the maximum at the point where the groove is located, and the width gradually decreases from there toward the center.

Thereby, the cross-sectional area of each surface of the case body 1 (7) can be set small regardless of the presence of the ribs 4 and 5, and at the same time, the vicinity of the nodes of the vibration mode can be strengthened.

This is effective in reducing the high-frequency noise mentioned above, and also increases the rigidity of the joint between the case body 1 and the clutch housing.

As described above, this idea reduces the weight of the case body and at the same time significantly reduces the radiated noise caused by internal gear noise by making the case body curved and arranging ribs at the most effective locations on its outer periphery. can be suppressed.

[Brief explanation of drawings]

The drawings show an embodiment of this invention, with FIG. 1 being an external perspective view of the case body, and FIG. 2 being a sectional view thereof. 1...Case body, 2...Recess, 3.
...Annular rib, 4,5...Rib.

Claims (1)

[Scope of utility model registration request] One side of the case body is curved inward, and two annular ribs are placed on the outer periphery in a shape that emphasizes the curvature of the side. Continuous ribs are formed on both sides of the case body, and the ribs on the top and bottom are thicker than the ribs on both sides, and the width of each rib is the maximum at both ends of the case body. The transmission case is characterized by being set to be the smallest in the center.