Power plants – Pressure fluid source and motor – Pulsator
Reexamination Certificate
2000-04-18
2002-08-27
Look, Edward K. (Department: 3745)
Power plants
Pressure fluid source and motor
Pulsator
C060S585000
Reexamination Certificate
active
06438955
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a master cylinder, which is suitable for use in a clutch operating unit, a brake operating unit, or the like.
FIG. 26
is a cross sectional view showing one example of a master cylinder related to the present invention, which is disclosed in Japanese Patent Provisional Publication No. 10-53120. This master cylinder
1
has a piston
3
which is freely slidably fitted in a cylinder hole
2
a
formed in a cylinder body
2
, and by the piston
3
and the cylinder body
2
, a pressure generating chamber
4
and a hydraulic fluid waiting chamber
5
are sectioned. To the piston
3
, a valve mechanism
6
and a throttle valve mechanism
7
are attached on the extension of the axis. In the valve mechanism
6
, a flange
10
integrated with a rod
9
is separated from a circular member
11
to open an axial hole
12
as the piston
3
retreats to the restoration position by a return spring
8
provided in the pressure generating chamber
4
, and the flange
10
comes into contact with the circular member
11
to close the axial hole
12
as the piston
3
advances from the restoration position.
Furthermore, the throttle valve mechanism
7
is equipped with a floating member
13
having a throttle hole
13
a
, and when there is a flow of hydraulic fluid running toward a reservoir through the axial hole
12
from the pressure generating chamber
4
, it moves the floating member
13
to the throttled operating position where the throttling effect is exhibited to the flow of the hydraulic fluid, and when there is a flow of hydraulic fluid running toward the pressure generating chamber
4
through the axial hole
12
from the reservoir, it moves the floating member
13
to the unthrottled operating position where no throttling effect is exhibited to the flow of the hydraulic fluid.
Then, from the state where the valve mechanism
6
is open, the piston
3
operates, and it moves to the left in the figure and advances, so that the valve mechanism
6
may be closed, and the continuity between the pressure generating chamber
4
and the supplement passage
5
is cut off. After that, the piston
3
further moves to the left, and consequently, pressure is generated in the pressure generating chamber
4
, and the hydraulic fluid is discharged from an output port
14
. Until the valve mechanism
6
is closed after the start of advancing of the piston
3
, the hydraulic fluid in the pressure generating chamber
4
escapes to the supplement passage
5
through the throttle valve mechanism
7
and the valve mechanism
6
by the advancing of the piston
3
. By the flow of the hydraulic fluid at that moment, the floating member
13
of the throttle valve mechanism
7
closes a connecting hole
15
a
of a case
15
. As a result of this, the hydraulic fluid in the pressure generating chamber
4
escapes to the supplement passage
5
through the throttle hole
13
a
of the floating member
13
, so that the amount of the hydraulic fluid escaping to the supplement passage
5
from the pressure generating chamber
4
may be reduced when compared with that in the case when the flow of the hydraulic fluid escaping to the supplement passage
5
from the pressure generating chamber
4
is not throttled.
However, in the above master cylinder
1
, a throttle valve mechanism
7
is provided on the extension of the axis of the piston
3
, and therefore, there has been such a problem that the piston
3
becomes long, and the whole of the master cylinder
1
becomes large-sized, and the structure becomes complex, and the number of pieces of necessary parts is increased.
OBJECT AND SUMMARY OF THE INVENTION
The present invention is made due to the above problems, and it is an object thereof to provide a master cylinder, in which the function of a throttle valve mechanism can be exhibited without making the whole of the master cylinder large-sized and the structure is simple and the number of pieces of parts can be reduced.
In order to attain the above object, the present invention provides a master cylinder, in which a piston is freely slidably provided in a cylinder hole formed in the cylinder body and by the above piston and the above cylinder body, a pressure generating chamber is sectioned, and a fluid passage for connecting the pressure generating chamber and a reservoir in order to supplement the hydraulic fluid to the pressure generating chamber is provided, and the hydraulic fluid pumped in the above pressure generating chamber when the piston operates is discharged to the output port, wherein a throttle passage which throttles the flow of the hydraulic fluid to the reservoir from the pressure generating chamber when the above piston operates is formed in the fluid passage, and a throttle valve mechanism which allows the hydraulic fluid to flow to the pressure generating chamber from the reservoir by opening a valve when the fluid pressure in the pressure generating chamber becomes lower than the pressure in the reservoir is provided in the fluid passage.
Furthermore, in the present invention, the throttle valve mechanism may be constituted by having a floating valve body, and a valve seat with and from which the floating valve body is brought into contact and is separated may be provided on the connecting portion to the cylinder body of the reservoir, and a fluid passage which supplements the hydraulic fluid to the pressure generating chamber from the reservoir when the valve of the throttle valve mechanism opens may be formed in either the throttle valve mechanism or the cylinder body, and a throttle passage can be provided in the fluid passage in parallel with the floating valve body, and the throttle valve mechanism may have a ball valve which performs opening and closing by the flow of the hydraulic fluid in the fluid passage and by its own weight and a throttle passage which is formed in parallel with the ball valve, and the ball valve may have a ball-shaped floating valve body; a valve seat with and from which the floating valve body is brought into contact and is separated; a slant face continuous with the valve seat and slanted in the direction in which the floating body rises when sitting, a waiting seat where the floating valve body is waiting apart from the valve seat when not operating; and a stopper which regulates a position where the floating valve body is waiting apart from the valve seat, and it is also possible that a circular piston guide is arranged around the periphery of the piston and the fluid passage is formed in the piston guide and a throttle passage which connects the fluid passages before and after the ball valve to make a detour is provided in the above piston guide.
Furthermore, the present invention provides a master cylinder, in which a piston is freely slidably provided in a cylinder hole formed in the cylinder body and by the piston and the cylinder body, a pressure generating chamber is sectioned and a fluid passage for connecting the pressure generating chamber and reservoir in order to supplement the hydraulic fluid is provided and the hydraulic fluid pumped in the pressure generating chamber when the piston operates is discharged to the output port, wherein a circular piston guide and a seal member may be arranged around the periphery of the piston and a circular chamber communicating with the reservoir may be constituted between the piston guide and the seal member and in the circular chamber, a circular floating valve body with a throttle passage for throttling the flow of the hydraulic fluid and a seating face with which the floating valve body comes into contact may be provided.
Also, the present invention provides a master cylinder, in which a cylindrical piston is freely slidably provided in a cylinder hole formed in the cylinder body and by the piston and the cylinder body, a pressure generating chamber is sectioned and a fluid passage for connecting the pressure generating chamber and reservoir in order to supplement the hydraulic fluid is provided and the hydraulic fluid pumped in t
Chiba Shusaku
Sugimoto Riichirou
Alston & Bird LLP
Bosch Braking Systems Co. Ltd.
Kershteyn Igor
Look Edward K.
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