JPH038523Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a tandem master cylinder mainly used in two-system hydraulic brakes for automobiles.

(2) Prior Art Conventionally, in a master cylinder for an automobile, the rear end of a cylinder body having independent front and rear hydraulic chambers is attached to the vehicle body, as shown in, for example, Japanese Unexamined Patent Publication No. 167546/1983. In the cylinder body,
An oil reservoir having front and rear oil reservoir chambers separated by a partition wall is arranged adjacent to the rear hydraulic chamber, and a relief hole and a supply hole for the rear hydraulic chamber are opened in the bottom of the rear oil reservoir chamber, It is known that an oil passage projecting from the cylinder body communicates the rear oil reservoir chamber with the relief hole and supply hole of the front hydraulic chamber.

(3) Problems to be solved by the invention In the conventional master cylinder mentioned above, the oil sump is placed relatively close to the car body that supports the cylinder body, so the gap between the car body and the oil sump is large. , which is disadvantageous when attempting to install various auxiliary equipment between them.

This invention was made in view of these points,
Although the oil sump is placed at the front end of the cylinder body to maximize the distance between the vehicle body and the oil tank, an oil passage drilled into the cylinder body allows the front and rear oil sump chambers in the oil sump to be connected to the cylinder. It is an object of the present invention to provide a tandem type master cylinder that can reliably transfer hydraulic oil between front and rear hydraulic chambers in a main body.

B. Structure of the device (1) Means for solving the problems In order to achieve the above object, the present invention consists of a cylinder body having independent front and rear hydraulic chambers inside and whose rear end is supported by the vehicle body. An oil reservoir is connected to the front end,
This oil reservoir is provided with a front and rear oil reservoir chamber separated by a partition wall, and a first oil passage is bored in the cylinder body to connect the rear oil reservoir chamber to the relief hole and supply hole of the rear hydraulic chamber. A second oil passage communicating the front oil sump chamber with the relief hole and supply hole of the front hydraulic chamber is bored in the cylinder body passing below the bottom of the rear oil sump chamber. and the second oil passages are spaced apart from each other in the circumferential direction of the cylinder body.

(2) Effect According to the above configuration, although the oil reservoir is arranged at the front end of the cylinder body forward of the relief hole and supply hole of the hydraulic chamber,
With oil passages, hydraulic oil can be reliably exchanged between the front and rear oil sump chambers in the oil sump and the front and rear hydraulic chambers in the cylinder body, resulting in a smooth flow between the vehicle body and the oil sump. You can maximize the distance between

In addition, since the first and second oil passages are spaced apart from each other in the circumferential direction of the cylinder body, the wall thickness of the side wall of the cylinder body does not have to be particularly thick. You can also take enough.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a cylinder body 1 of a tandem-type master cylinder M for automobile brakes is shown.
is arranged at a constant angle θ tilted forward upward with respect to the horizontal line X, and the mounting flange 1a at the rear end
is fixed to the front surface of a dash board B that partitions the vehicle interior Rp and the engine room Re through bolts (not shown). At this time, in order to incline the cylinder body 1, inclining the master cylinder mounting surface Ba of the dash board B by a certain angle θ with respect to the vertical line Y as shown in the example shown in FIG.
Since the mounting flange 1a can be formed perpendicular to the axis of the cylinder body 1, it is easy to manufacture the cylinder body 1.
It is also advantageous in reducing the overall length of the cylinder body 1.

By arranging the cylinder body 1 so that it is tilted upward in the front, the space below the cylinder body 1 is expanded, and the engine or its auxiliary equipment can be easily installed there.

In the cylinder hole 2 of the cylinder body 1, independent front and rear hydraulic chambers 4, 4' are defined by a pair of front and rear pistons 3, 3' that slide into the cylinder hole 2, and these hydraulic chambers 4, 4' Output port 4 of
The two-system brake hydraulic circuit of the automobile is connected to a and 4a'.

An oil reservoir R is connected to the upper side of the frontmost end of the cylinder body 1. This oil sump R consists of an auxiliary oil sump 5 cast together with the cylinder body 1, and a main oil sump 6 made of transparent synthetic resin whose lower end is fitted and connected to the outer periphery of this auxiliary oil sump 5. 6 has a larger volume than the auxiliary oil sump 5, and is provided with a single cap 8 at its upper end.

The auxiliary oil reservoir 5 is formed by a partition wall 9 that is integral with the cylinder body 1.
The interior is divided into a front oil sump chamber 5a and a rear oil sump chamber 5b.
Both oil reservoir chambers 5a and 5b communicate with a main oil reservoir 6.

The main oil sump 6 is provided with an oil level sensor 10, which issues an activation signal to an alarm (not shown) when the oil level of the hydraulic oil stored in the oil sump R drops below a specified lower limit level. There is.

The upper wall of the cylinder body 1 includes a rear oil reservoir chamber 5b.
Relief hole 11' and supply hole 12' of rear hydraulic chamber 4'
a first oil passage 13 that communicates with the front oil reservoir chamber 5a and a second oil passage 1 that communicates the front oil reservoir chamber 5a with the relief hole 11 and supply hole 12 of the front hydraulic chamber 4 through the bottom of the rear oil reservoir chamber 5b.
4 (see Figures 2 and 4) are drilled, and both oil passages 1
3 and 14 are arranged spaced apart from each other in the circumferential direction of the cylinder body 1 (see FIG. 3).

Further, both oil passages 13 and 14 are connected to the corresponding oil reservoir chamber 5.
It is arranged parallel to the cylinder hole 2 so as to have an upward slope toward a and 5b.

The first oil passage 13 is bored from the rear end face of the cylinder body 1, and the second oil passage 14 is bored from the front end face of the cylinder body 1, respectively, by means of a cone, and each perforation port is closed by a spherical blind plug 15, 16. (See Figures 1 and 2). In addition, the relief holes 11, 11' and the supply hole 1
2 and 12' are perforated from the outer circumferential surface of the cylinder body 1 with a drill, and their perforation openings are also spherical blind plugs 17 and 1.
7' and 18, 18' (second,
(See Figure 4).

In the vehicle interior Rp, a brake pedal (not shown) is connected to the rear piston 3' via a procedure rod 19.

In FIG. 1, when the rear piston 3' and the front piston 3 are sequentially pushed forward via the push rod 19 by pressing the brake pedal, the pistons 3, 3' move into the relief holes 11, 3'.
11', hydraulic pressure is generated in each hydraulic chamber 4, 4' as the pistons 3, 3' move forward, and is outputted from the output ports 4a, 4a' and transmitted to the corresponding brake hydraulic circuit. , activates the brakes on each wheel. Furthermore, when the pistons 3, 3' are retracted, hydraulic oil is supplied to the front and rear hydraulic chambers 4, 4' from the front and rear oil reservoir chambers 5a, 5b through the supply holes 12, 1.
2', and the excess replenishment is returned to the front and rear oil sump chambers 5a, 5b through the relief holes 11, 11'.

During such operation, the first and second oil passages 13, 14
If bubbles are generated in the oil passages 13 and 14, the oil sump R
Since the air bubbles are sloped upward toward the front and rear oil reservoir chambers 5a and 5b, the air bubbles can be quickly discharged to the front and rear oil reservoir chambers 5a and 5b.

Now, if an oil leak failure occurs in the hydraulic circuit of the front hydraulic chamber 4 system, even if the hydraulic oil in the main oil reservoir 6 and the front oil reservoir chamber 5a of the auxiliary oil reservoir 5 dries up, the auxiliary oil reservoir Since the hydraulic oil remains in the rear oil sump chamber 5b of the oil sump 5, both pistons 3 and 3'
As the rear hydraulic chamber 4' moves forward, the pressure in the rear hydraulic chamber 4' can be increased, and the hydraulic circuit of the system can be operated normally.

If the hydraulic circuit of the rear hydraulic chamber 4' system fails, the same effect as described above will occur, except that hydraulic oil remains in the front oil reservoir chamber 5a of the auxiliary oil reservoir 5.

In such a tandem type master cylinder, the front oil reservoir chamber 5a of the oil reservoir R is replaced with the rear oil reservoir chamber 5b.
Because it is linked to the relief hole 11 and supply hole 12 of the front hydraulic chamber 4 via the second oil passage 14 passing through the bottom of the
The front end of the oil sump R can be placed in the cylinder body 1, the distance between the oil sump R and the dash board B can be widened to the maximum, and various accessories can be easily arranged between them.

Furthermore, although there are parts of the first and second oil passages 13 and 14 that are arranged parallel to each other, since both oil passages 13 and 14 are spaced apart in the circumferential direction of the cylinder body 1, the side wall of the cylinder body 1 is made particularly thick. Both oil lines 1
3 and 14, and by extension, a sufficient distance between each oil passage 13, 14 and the cylinder hole 12.

C. Effects of the invention As described above, according to the invention, an oil reservoir is connected to the front end of the cylinder body, which has independent front and rear hydraulic chambers inside and whose rear end is supported by the vehicle body. A front oil reservoir chamber and a rear oil reservoir chamber partitioned by a partition wall are provided in the reservoir, and a first oil passage is bored in the cylinder body to communicate the rear oil reservoir chamber with a relief hole and a supply hole of the rear hydraulic chamber, Further, a second oil passage communicating the front oil reservoir chamber with the relief hole and supply hole of the front hydraulic chamber is bored in the cylinder body through the bottom surface of the rear oil reservoir chamber, and these first and second oil passages Since the oil passages are spaced apart from each other in the circumferential direction of the cylinder body, the front end of the oil sump can be placed in the cylinder body, maximizing the distance between the vehicle body and the oil sump, making it convenient to install various accessories between them. You can get used to it.

In addition, even without making the side wall of the cylinder body particularly thick, it is possible to maintain sufficient spacing not only between the first and second oil passages but also between them and the cylinder hole, thereby preventing mutual communication through the blowhole. Therefore, the occurrence of casting defects in the cylinder body is extremely small.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of a tandem type master cylinder installed in an automobile, Fig. 2 is a plan view of the cylinder body,
3 is a cross-sectional view taken along the line -- in FIG. 2, FIG. 4 is a cross-sectional view taken along the line -- in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line -- in FIG. B...Dutsche board that is part of the vehicle body, M...
...Tandem type master cylinder, R...Oil sump, 1...
...Cylinder body, 2...Cylinder hole, 3, 3'...
...Front, rear piston, 4, 4'...Front, rear hydraulic chamber, 5a, 5b...Front, rear oil sump chamber, 9...Partition wall, 11, 11'...Relief hole, 12, 12'... Replenishment holes, 13, 14...first and second oil passages.

Claims (1)

[Scope of utility model registration request] An oil reservoir R is connected to the front end of the cylinder body 1, which has independent front and rear hydraulic chambers 4, 4' and whose rear end is supported by the vehicle body B. Inside this oil reservoir R, a partition wall 9 is installed. Front and rear oil storage chambers 5a, 5 divided by
b, and a first oil passage 13 is bored in the cylinder body 1, which communicates the rear oil reservoir chamber 5b with the relief hole 11' and supply hole 12' of the rear hydraulic chamber 4'. 5a to the relief hole 11 and supply hole 12 of the front hydraulic chamber 4 is bored in the cylinder body 1 through the bottom surface of the rear oil reservoir chamber 5b. A tandem type master cylinder characterized in that two oil passages 13 and 14 are spaced apart from each other in the circumferential direction of the cylinder body 1.