JPH0426743Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a parking brake drum for a vehicle, and in particular, aims to improve vehicle speed detection accuracy by increasing strength and suppressing deformation of the vehicle speed detection convex part while having a vehicle speed detection function. Regarding the ivy parking brake drum. In other words, automatic transmission devices that automatically shift gears by controlling a mechanical clutch and a gear-type transmission using a microcomputer have been put into practical use, but such devices do not allow accurate control of the running conditions of the vehicle, especially the running speed of the vehicle. Good detection is extremely important. The present invention relates to an improvement of a device that detects pulses for detecting vehicle speed using irregularities provided on the parking brake drum.

Prior Art A conventional parking brake drum 1 of this type will be explained with reference to FIGS. 4 to 6. The parking brake drum 1 is formed into a cylindrical shape with an open end 1a on the transmission 2 side. The propeller shaft side wall portion 1b was fixed to the propeller shaft yoke 3, and a plurality of vehicle speed detection convex portions 1c were formed at regular intervals on the end portion 1a. A vehicle speed sensor 4 is attached to a part of the transmission 2 so as to face the vehicle speed detection protrusion 1c, and counts pulses generated from the vehicle speed detection protrusion 1c as the parking brake drum 1 rotates. It was now possible to measure vehicle speed with high accuracy. A pair of inwardly expanding shoes 5 are installed inside the parking brake drum 1, and by operating a parking brake lever (not shown), the cylindrical portion 1d of the parking brake drum 1 can be operated.
The parking brake can be applied by pressing the inner circumferential surface 1e of the vehicle.

However, according to the conventional example as described above, since a plurality of vehicle speed detection convex portions 1c are formed on the end portion 1a of the parking brake drum 1 itself, the parking brake is removed from the brake 5 as shown by arrow A in FIG. When a pressing force acts on the inner circumferential surface 1e of the cylindrical portion 1d of the drum 1, the cylindrical portion 1d deforms outward as shown by the imaginary line, and the end portion 1a expands. As a result of the deformation, a shift occurs in the positional relationship of the convex portion 1c with respect to the vehicle speed sensor 4, and there is a possibility that the accuracy of vehicle speed detection may deteriorate. Another disadvantage is that the strength of the parking brake drum 1 is reduced by the presence of the convex portion 1c.

Purpose The present invention was made in order to eliminate the above-mentioned problems of the prior art, and its purpose is to prevent the parking brake drum from forming a convex portion for detecting vehicle speed on the main body of the parking brake drum. The transmission side end of the brake drum body is formed flat to increase the strength of the parking brake drum against the pressing force of the parking brake. suppresses misalignment,
The object of the present invention is to maintain good vehicle speed detection accuracy. Another object of the present invention is to connect the propeller shaft side end of a cylindrical member having a plurality of vehicle speed detection convex parts formed at regular intervals on the transmission side end to the propeller shaft side wall of the parking brake drum body and the cylindrical part. By fixing it to the outer circumferential surface of the bent part in between, for example, in the case of welding, the welding strength can be reduced. Still another object is to provide a gap between the outer circumferential surface of the brake drum body and the inner circumferential surface of the cylindrical member, so that even if the parking brake drum body is deformed, the deformation is not used for vehicle speed detection. The purpose is to avoid affecting the convex portion.

Configuration In short, the present invention has a brake drum main body which is formed into a cylindrical shape with an open end on the transmission side, and the end thereof is formed flat, and the end between the propeller shaft side wall and the cylindrical portion of the brake drum main body is flat. The propeller shaft side end of a cylindrical member having a plurality of vehicle speed detection protrusions formed at regular intervals on the transmission side end is fixed to the outer peripheral surface of the bent part of the cylindrical member. be.

The present invention will be explained below based on embodiments shown in the drawings. 1 to 3, the parking brake drum 11 according to the present invention has a brake drum main body 21 formed in a cylindrical shape with an open end 21a on the side of the transmission 12. The end 21a of the brake drum body 21 is formed flat. At the same time, the brake drum body 21
propeller shaft side wall portion 21b and cylindrical portion 21d
A cylindrical member 18 in which a plurality of vehicle speed detection protrusions 18c are formed at regular intervals on the outer circumferential surface 21g of the bent portion 21f between the transmission 12 and the transmission 12 side end 18a.
The propeller shaft side end 18b of the propeller shaft is fixedly attached.

When the cylindrical member 18 is made of a magnetic material such as iron, the end portion 18b may be fixed to the brake drum body 21 by welding. In addition, when the cylindrical member 18 is made of non-magnetic material such as non-ferrous metal or synthetic resin,
Only the vehicle speed detecting convex portion 18c may be formed of a magnetic material such as iron, and the end portion 18b may be fixed to the brake drum body 21 by brazing, adhesive, or the like.

Also, the outer peripheral surface 21h of the brake drum body 21
and the inner peripheral surface 18c of the cylindrical member 18,
A gap C is provided so that the cylindrical member 18
The inner circumferential surface 18e thereof is formed to expand toward the transmission 12 side.

In the illustrated embodiment, the vehicle speed detection convex portion 18c of the cylindrical member 18 is formed radially outward, but it may be formed toward the transmission 12 side as in the conventional example. is clear.

In addition, the propeller shaft yoke 3, vehicle speed sensor 4, and pair of inwardly expanding shoes 5 are the same as those in the conventional example shown in FIG. 4, so a description thereof will be omitted.

Function The present invention is constructed as described above, and its function will be explained below. Vehicle speed detection convex portion 18c
The cylindrical member 18 formed with is fixed to the brake drum body 21, and the vehicle speed detection convex portion 18c is disposed facing the vehicle speed sensor 4, so that when the brake drum body 21 rotates, magnetic material is removed. The interaction between the vehicle speed detection convex portion 18c and the vehicle speed sensor 4 generates one pulse per convex portion, and by measuring this pulse per unit time, the vehicle speed of the wheel can be measured. can.

Also, if you use the parking brake,
As in the conventional example, as shown in FIG. 3, a force that causes the cylindrical portion 21d to expand is applied from the pair of inwardly expanding shoes 5 to the inner circumferential surface 21e of the brake drum body 21 as indicated by arrow A. Since the transmission side end portion 21a is formed flat, stress concentration does not occur at the end portion, and therefore the strength of the end portion is increased compared to the conventional example. The amount by which the cylindrical portion 21d is deformed by such a force is reduced.

Furthermore, even if the cylindrical portion 21d is deformed, a gap C is formed between the inner circumferential surface 18e of the cylindrical member 18 and the outer circumferential surface 21h of the brake drum body 21. The vehicle speed detection convex portion 18c is not affected by the vehicle speed detection convex portion 18c with respect to the vehicle speed sensor 4.
The position of the vehicle does not change, so it is possible to maintain good accuracy in detecting the vehicle speed by the vehicle speed sensor 4 at all times. In addition, only the propeller shaft side end 18b of the cylindrical member 18 is located at the bent portion 2 of the brake drum body.
Since it is fixed to the outer circumferential surface 21g of 1f by means such as welding, the amount of deformation in this part is small, so there is no need to increase the strength of the fixing means such as welding, and sufficient strength can be obtained. It is something that can be done.

Effects As described above, the present invention forms the transmission side end of the parking brake drum body flat by not forming a convex portion for detecting vehicle speed on the parking brake drum body, so that the parking brake drum body is not pushed by the parking brake. It is possible to increase the strength of the parking brake drum against pressure, and as a result, it is possible to suppress positional deviation of the vehicle speed detection convex portion with respect to the vehicle speed sensor, resulting in the effect that vehicle speed detection accuracy can be maintained satisfactorily. In addition, the propeller shaft side end of the cylindrical member, which has a plurality of vehicle speed detection convex portions formed at regular intervals on the transmission side end, is connected to the bent portion between the propeller shaft side wall of the parking brake drum body and the cylindrical member. Since it is fixed to the outer circumferential surface, it is possible to obtain the effect that, for example, in the case of welding, the welding strength can be reduced. Furthermore, since a gap is provided between the outer circumferential surface of the brake drum body and the inner circumferential surface of the cylindrical member, even if the parking brake drum body is deformed, the deformation will not affect the vehicle speed detection convex portion. The effect is that there is no

[Brief explanation of the drawing]

1 to 3 relate to an embodiment of the present invention; FIG. 1 is a vertical sectional view of main parts showing the mutual relationship between the parking brake drum, a pair of inwardly expanding shoes, the vehicle speed sensor, and the transmission; Figure 2 is a perspective view of the parking brake drum, Figure 3 is an enlarged vertical cross-sectional view of the main parts of the parking brake drum, Figures 4 to 6 relate to the conventional example, and Figure 4 is a vertical cross-section similar to Figure 1. Figure 5 is a perspective view similar to Figure 2, Figure 6 is a perspective view similar to Figure 2;
The figure is an enlarged longitudinal sectional view similar to FIG. 3. 11 is a parking brake drum, 12 is a transmission, 18 is a cylindrical member, 18a is an end on the transmission side, 18b is an end on the propeller shaft side, 18c is a convex portion for detecting vehicle speed, 18e is an inner peripheral surface, 21 21a is the transmission side end, 21b is the propeller shaft side wall, 21d is the cylindrical part, 21f is the bent part,
21g is the outer circumferential surface of the bent portion, 21h is the outer circumferential surface of the cylindrical portion, and C is the gap.

Claims (1)

[Claims for Utility Model Registration] 1. A brake drum body which is formed into a cylindrical shape with an open end on the transmission side. The propeller shaft side end of a cylindrical member having a plurality of vehicle speed detection convex parts formed at regular intervals on the transmission side end is fixed to the outer peripheral surface of the bent part between the parts. parking brake drum. 2. The parking brake drum according to claim 1, wherein a gap is provided between the outer peripheral surface of the brake drum body and the inner peripheral surface of the cylindrical member.