JPH0449551Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a reserve tank for an automobile brake master cylinder.

(Prior Art) Conventionally, as shown in FIG. 3, a sealed reserve tank 2 for a master cylinder 1 employed in a hydraulic brake system of an automobile has a float within a tank body 3 that follows the liquid level L1. A main body 4 is provided, and when the float main body 4 is lowered to its lowest position, a magnet 5 fixed to the lower part of the float main body 4 is
A sensor (proximity switch, etc.) 6 provided on the bottom 3a of the tank body 3 detects this and warns the driver of a drop in the liquid level, which has been put into practical use.

By the way, as shown on the left side of Fig. 4b, even if the float body 4 descends to its lowest point and an alarm is issued, the minimum liquid level _L2 must be maintained, so the float A height ₂ corresponding to the liquid level L ₂ is required below the water line F of the main body 4, and the total height ₁ of the float main body 4 has to be increased. Furthermore, in order to secure the capacity of the tank, which is reduced by the height ₂ , the diameter _d1 of the float body 4 had to be made thinner.

Therefore, since the float body 4 is tall, the liquid level _L1 drops from the floating state on the left side of Figure 4a to _L2 , and becomes the lowest position on the left side of Figure 4b. When this happens, it protrudes upward from the bottom 3a of the tank body 3 by a height corresponding to the total height ₁ .
A diaphragm 7, which is provided at the opening of the tank body 3 and follows changes in the liquid level, is connected to the float body 4.
When the liquid level drops below the set level, a vacuum is generated in the tank, and if there is a leak, air will be sucked in from that area. The brakes may become ineffective.

This problem can be solved by setting the height of the tank body high enough to avoid interference, but this requires wasted space inside the tank, which goes against the demand for compactness that corresponds to lower bonnets. .

Further, since the float main body 4 is thin, the center of gravity is at an upper position, making it unstable against external factors such as vibration, and there is a risk of malfunction.

(Purpose of the invention) This invention was devised to solve the above-mentioned conventional problems, and allows the overall height of the tank to be set low, while also reliably avoiding interference between the diaphragm and the float when the liquid level drops. It is an object of the present invention to provide a reserve tank for a brake master cylinder for an automobile, which can operate stably even in the presence of vibrations, etc.

(Structure of the invention) For this reason, the present invention has a float main body 1 which stores brake fluid in a sealed state and is equipped with a diaphragm on the upper part that follows the liquid level.
4 is lowered by a predetermined amount, the float body 14 connects the lower magnet 15 to the bottom 13 of the tank body 13.
In the reserve tank of a brake master cylinder for an automobile, which is configured to detect a drop in the liquid level by the sensor 16 of FIG. A locking portion 21a is provided at the upper end of the guide shaft, and an upwardly convex concave portion is formed at the center of the diaphragm, while a sleeve 20 with a magnet 15 attached to the lower end is provided on the guide shaft. The upper end of the sleeve 20 has a collar portion 20a.
, while the float body 14 has a height of
₃ is set below the height of the required minimum liquid level, and the diameter d ₂ is set larger than the height ₃ to ensure the required buoyancy. A guide hole 14a is provided which is slightly larger than the diameter of the collar of the sleeve, and a small diameter hole is provided at the lower end of the guide hole 14a, which is smaller in diameter than the collar of the sleeve and slightly larger than the diameter of the sleeve body. The highest position of the float is determined by engaging the small diameter hole of the float with the collar 20a of the sleeve and stopping the collar with the locking portion 21a of the guide shaft. If the float falls further below the specified amount above, the float is relatively lowered by the height of the sleeve while the magnet is in contact with the bottom of the tank body, until the float reaches its lowest position where it does not interfere with the diaphragm. To provide a reserve tank for a brake master cylinder for an automobile, which is configured to take the following values.

(Effects of the invention) According to the invention, the float can be made into a flat structure, and when the liquid level drops below the set level, the float can be lowered further, so the overall height of the reserve tank can be lowered. In addition, interference between the diaphragm and the float can be reliably avoided, and brake operation can be reliably guaranteed.

Further, since the float is guided in the vertical direction by the guide shaft and the sleeve, the float can be raised and lowered stably and smoothly, and the reliability of the brake master cylinder can be ensured.

(Example) As shown in FIGS. 1 and 2, the sealed reserve tank 12 includes a cylindrical tank body 13, and a bottom 13a of the tank body 13 is provided with liquid supply ports 13b, 13b. master cylinder 1
1 is connected to the tank body 13, and a cap 18 is screwed onto the upper part of the tank body 13.
A diaphragm 17 is sandwiched between the tank body 13 and the tank body 13 via a back-up spring 19. This diaphragm 17 descends as the liquid level falls.

On the other hand, the float main body 14 has a diameter d ₂ larger than that of the conventional float body 14 instead of having a lower overall height ₃ to ensure the required buoyancy, and a guide hole 14 is provided at the axial center position.
a, and the magnet 15 is fixed to the lower part of the support sleeve 20.
The upper part of the float body 14 is fitted into the guide hole 14a of the float body 14 so as to be able to move up and down, and the small diameter part provided at the lower end of the guide hole 14a is prevented from coming off by the upper edge flange part 20a. Support so that it can be raised and lowered. In addition, the above float body 1
The height of No. 4 is set sufficiently lower than the liquid level L ₂ in the state shown in Figure 2 when the liquid level drops and an alarm is issued, and even when the liquid level falls below the set level,
The diaphragm 17 is prevented from interfering with the float body 14.

The support sleeve 20 to which the float body 14 and the magnet 15 are assembled is fitted into a guide shaft 21 provided at the center of the bottom of the tank body 13 so as to be able to rise and fall freely, and is prevented from coming off by a hook portion 21a provided at the upper end.
The height of the guide shaft 21 is set at the highest position of the float body 14, that is, when the sleeve 20 is at the hook portion 21a.
The magnet 15 is set to be able to be lifted to a predetermined height above the bottom surface of the tank when the tank is locked. As shown in FIG. 1, an upwardly convex recess is formed in the center of the diaphragm 17, so that when the diaphragm 17 is lowered, the guide shaft 1
7 so as not to interfere with the upper end 17a.

A sensor 16 is provided at the bottom 13a of the tank body 13 where the guide shaft 21 is located.

With the above configuration, normally the float body 14 follows the liquid level L ₁ and the magnet 15 is lowered by its own weight, so the total height of these
₁ is the same as the conventional total height ₁ , so it functions in the same way as the conventional one (see the right side of Figure 4a).

Next, when the liquid level _L1 drops to _L2 , the sensor 16 activates the magnet 15 as in the conventional case.
is detected, and the driver is alerted to the drop in the liquid level (see the right side of Figure 4b).

If the diaphragm 17 operates further downwards due to a further drop in the liquid level from this liquid level _L2 (see the two-dot chain line on the right side of Fig. 4b), the float body 14 moves from the lowest position to the magnet. Since the diaphragm 17 can be further lowered by a length ₄ until it comes into contact with the float body 15, the operation of the diaphragm 17 is no longer restricted by the float body 14.

Further, since the float main body 14 is flat, the center of gravity is at a lower position, so it is stable against external factors such as vibration.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a reserve tank equipped with a float according to the present invention, Figure 2 is a sectional view of the main part of a reserve tank with the float body in the lowest position, Figure 3 is a sectional view of a conventional reserve tank, and Figure 3 is a sectional view of a conventional reserve tank. 4a and 4b are operation explanatory diagrams that compare and show the operating states of the float main body according to the present invention and the conventional float main body. The guide shaft is omitted. 12... Reserve tank, 13... Tank body, 13a... Bottom, 14... Float body, 1
5...Magnet, 16...Sensor, 20...
Support sleeve, L ₁ , L ₂ ...Liquid level, F...
Water line, ₁ , ₂ , ₃ , ₄ ...Length, d ₁ , d ₂ ...
…diameter.

Claims (1)

[Claims for Utility Model Registration] Brake fluid is contained in a sealed state, and a diaphragm that follows the liquid level is provided at the upper part, and when the float body 14 that follows the liquid level descends by a predetermined amount, In the reserve tank of an automobile brake master cylinder, in which the magnet 15 is detected by a sensor 16 on the bottom part 13a of the tank body 13 to warn of a drop in the liquid level, there is a required minimum liquid level in the center of the bottom of the tank body 13. A guide shaft 21 higher than the height of the level is provided upright, a locking portion 21a is provided at the upper end of the guide shaft, an upwardly convex recess is formed at the center of the diaphragm, and a lower end of the guide shaft is provided. A sleeve 20 to which a magnet 15 is attached is fitted in such a way that it can be raised and lowered freely, and the upper end of the sleeve 20 has a collar portion 20a.
, while the float body 14 has a height of
₃ is set below the required minimum liquid level, and the diameter d ₂ is set larger than the height ₃ to ensure the required buoyancy. A guide hole 14a is provided that is slightly larger than the diameter of the collar of the sleeve, and a small diameter hole that is smaller in diameter than the collar of the sleeve and slightly larger than the diameter of the sleeve body is provided at the lower end of the guide hole 14a. The highest position of the float is determined by engaging the small diameter hole of the float with the collar 20a of the sleeve and stopping the collar with the locking portion 21a of the guide shaft. When the float drops further below the above-mentioned predetermined amount, the float is relatively lowered by the height of the sleeve while the magnet is in contact with the bottom of the tank body, until the float reaches its lowest position where it does not interfere with the diaphragm. A reserve tank for an automotive brake master cylinder configured to take .