JPS63116971A - Portless type master cylinder device - Google Patents

Abstract

PURPOSE:To reduce an unavailable stroke of a piston as well as to aim at improvement in responsiveness, by installing a flow limiting device in an interconnecting passage between an inlet valve and a booster chamber, in the case of a vehicle brake master cylinder device or the like. CONSTITUTION:A push rod 49 makes piston members 3 and 4 go to the left against springs 7 and 8 by pedal operation, and when a piston cup 43 passages through a port 21, a first booster chamber 14 is intercepted from a reservoir 20 and thereby its pressure goes up. And, a rod 34 goes away from a stopper 23, a valve element 30 takes a valve seat part 32 by dint of a spring 33, and a second booster chamber 15 is intercepted from a reservoir port 24, thus its pressure goes up. During this while, the booster chamber 15 is interconnected to a reservoir interconnecting chamber 17, a fluid flows after being throttle by a throttle hole 28, and owing to this throttle effect, there is no difference between a dynamic stroke and static stroke of the piston and, what is more, a sudden pressure rise at time of valve closing of the valve element 30 or an inlet valve is avoided. Thus, an unavailable stroke of the piston is reduced, and responsiveness is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a master cylinder device used in a hydraulic brake device or a hydraulic clutch device in vehicles such as automobiles, and particularly relates to a master cylinder device of a portless type having an inlet valve. It concerns a master cylinder device.

BACKGROUND ART As a brake master cylinder device or a clutch master cylinder device used in vehicles such as automobiles, a pressure increasing chamber having an outlet port is provided on one side of a piston member, and a reservoir communication chamber is provided on the other side of the piston member. A one-way seal structure is incorporated in the member to prevent the flow of fluid from the pressurizing chamber to the reservoir communication chamber and to permit the flow of fluid in the opposite direction, and when the piston member is in the initial position, that is, the brake pedal or the clutch pedal When the pressurizing chamber is released, the valve is opened to communicate the pressurizing chamber and the reservoir communication chamber, and when the piston member is moved from the initial position by depression of a brake pedal or a clutch pedal, the valve is closed and communicating the pressurizing chamber and the reservoir. A portless master cylinder device having an inlet valve that cuts off communication with a communication chamber is already well known.
This is shown, for example, in Japanese Utility Model Application Publication No. 56-135348.

Problems to be Solved by the Invention In the above-mentioned portless type master cylinder device,
Even when the brake pedal or clutch pedal is depressed, the fluid in the booster chamber escapes to the reservoir communication chamber until the inlet valve closes, and this fluid flow is not substantially restricted, so the dynamic stroke of the piston and the static There is no difference in stroke, and the moment the inlet valve closes, the flow of fluid as mentioned above is suddenly cut off, so when the pedal is pressed quickly, the fluid pressure in the cylinder chamber rises rapidly. It is said that the non-resistance type master cylinder device has poor pedal operation feel compared to the conventional type master cylinder device.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an improved portless master cylinder device that provides a pedal operation feeling comparable to that of a conventional master cylinder device.

Means for Solving the Problems According to the present invention, a pressurizing chamber having an outlet port is provided on one side of the piston member, and a reservoir communication chamber is provided on the other side, and the piston member A one-way seal structure is incorporated in the pressurizing chamber to prevent the flow of fluid from the pressurizing chamber to the reservoir communication chamber and permitting the opposite fluid flow. In a portless master cylinder device having an inlet valve that communicates with a reservoir communication chamber and closes when the piston member moves from the initial position to cut off communication between the pressurization chamber and the reservoir communication chamber, This is achieved by a portless master cylinder device characterized in that a flow restriction means is provided in a communication passage connecting the inlet valve and the pressurizing chamber.

Effects and Effects of the Invention According to the above-described configuration, the fluid in the pressurizing chamber escapes to the reservoir communication chamber until the inlet valve closes.
This fluid flow is throttled by the flow restriction means, which creates a difference between the dynamic stroke and static stroke of the piston, similar to a typical conventional master cylinder device, and also causes the inlet valve to close. There is no sudden sudden rise in fluid pressure, and the same pedal operation feeling as a conventional master cylinder device can be obtained. Also, as mentioned above,
By restricting the flow of fluid, the invalid stroke of the piston is reduced and responsiveness is improved.

When the brake pedal or clutch pedal is released, the piston member returns to its initial position,
At this time, the return of the fluid from the outlet boat to the pressurizing chamber may be delayed due to flow path resistance or the like, and the pressurizing chamber may temporarily become in a negative pressure state. At this time, the fluid in the reservoir communication chamber pushes open the inlet valve and flows into the boosting chamber, and also flows through the one-way seal structure of the piston member to the boosting chamber. The flow is not obstructed and the pressurization chamber is not brought into a large negative pressure state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of embodiments with reference to the accompanying drawings.

1 and 2 show one embodiment in which the portless type master cylinder device according to the present invention is applied as a tandem master cylinder. In the figure, reference numeral 1 indicates a cylinder body, and the cylinder body has a relatively elongated cylinder bore 2 closed at one end. A first piston member 3 and a second piston member 4 are provided within the cylinder bore 2 so as to be movable in the axial direction.

Retainer 5 attached to one end of first piston member 3
Helical compression springs 7 and 8 are provided between the retainer 6 attached to the other end of the second piston member 4 and the end wall of the cylinder bore 2, respectively. ing. A stopper ring 9 is attached to the open end of the cylinder bore 2, and the stopper ring prevents the first piston member 3 from being pulled out of the cylinder bore 2. The first piston member 3 has two piston lands 10 and 11, and the second piston member 4 has two piston lands 12 and 13.

A first pressurizing chamber 1 is provided between the piston land 10 of the first piston member 3 and the piston land 12 of the second piston member 4.
4, and a second pressurizing chamber 15 is formed between the piston land 13 of the second piston member 4 and the end wall of the cylinder bore 2, respectively.

A reservoir communication chamber 16 is formed between the piston lands 10 and 11 of the first piston member 1, and another reservoir communication chamber 17 is formed between the piston lands 12 and 13 of the second piston member 4. ing.

The reservoir communication chamber 16 always communicates with the fluid reservoir port 18 formed in the cylinder body 1 regardless of the movement of the first piston member 3, and further communicates with the fluid reservoir port 18 through the reservoir connection port 19 provided in the cylinder body 1. It communicates with 20. The cylinder body 1 is provided with an orifice port 21 that communicates with the first pressurizing chamber 14 and the reservoir connection port 19 when the first piston member 3 is in the initial position as shown.

Further, although not shown in the figure, the cylinder body 1 is provided with an outlet port that communicates with the first pressurizing chamber 14 .

The second piston member 4 is provided with an elongated hole 22 that is long in the axial direction thereof, and a stopper pin 23 fixed to the cylinder body 1 passes through this elongated hole 22. The stopper pin 23 is activated by the second piston member 4 being biased rightward in the figure by the spring force of the compression coil spring 8.
As shown in the figure, the second piston member 4 is engaged with the left end portion of the elongated hole 22 to set the initial position (rightmost position) of the second piston member 4. The reservoir communication chamber 17 is always in communication with the fluid reservoir port 24 provided in the cylinder body 1 regardless of the movement of the second piston member 4, and further communicates with the fluid reservoir 20 through the reservoir connection port 25 provided in the cylinder body 1. It is connected to the. Further, the cylinder body 1 (; is provided with an outlet port 26 that communicates with the second pressurizing chamber 15.

The second piston member 4 has a cylindrical inlet valve chamber 2.
7 is provided, and the inlet valve chamber 27 communicates with the second pressurizing chamber 15 via the throttle hole 28 on one side, and a communication line provided along the axial direction of the second piston member 4 on the other side. It communicates with the reservoir communication chamber 17 via the hole 29 and the elongated hole 22 .

The inlet valve chamber 27 is provided with a valve element 30 as an inlet valve, and the valve element 30 is connected to the inlet valve chamber 27 of the communication hole 29 by a rubber backing member 31.
By seating on the valve seat portion 32 around the open end thereof, communication between the inlet valve chamber 27 and the communication hole 29 is cut off. The valve element 30 is urged to the right in the figure by the spring force of the compression coil spring 33 provided in the inlet valve chamber 27, that is, in the valve closing direction where it is seated on the valve seat portion 32, and the second piston member 4 When is in the initial position as shown in the figure, the rod 34 integral with the valve element 30 abuts the stopper pin 23 at its tip, so that the valve is in the valve open position a predetermined stroke away from the valve seat portion 3.2. It is supposed to be done.

Incidentally, piston cups 42 to 46, which are rubber seal members, are provided at each piston land portion of the first piston member 3 and the second piston member 4.

Also, the piston lands 10 and 13 have communication holes 47 and 4, respectively.
8 are provided, and these communication holes are connected to the reservoir communication chamber 16 by the check action of the piston cups 43 and 46, respectively.
．． Only the flow of fluid from 17 to the first and second pressurizing chambers 14 and 15 is allowed. That is, each of the first piston member 3 and the second piston member 4 includes a one-way seal structure that prevents the flow from the pressurizing chamber toward the reservoir communication chamber and allows the opposite flow.

When the brake pedal or the clutch pedal is released, both the first piston member 3 and the second piston member 4 are in the initial position as shown in FIG. It communicates with the fluid reservoir 20 through. Also, at this time, since the rod 34 is in contact with the stopper pin 23, the valve element 30 is displaced to the left in the figure against the spring force of the compression coil spring 33, and is moved to the valve open position away from the valve seat portion 32. be.

Therefore, at this time, the second pressurization chamber 15 communicates with the fluid reservoir 20 via the throttle hole 28, the inlet valve chamber 27, the communication hole 29, the elongated hole 22, the reservoir communication chamber 17, the fluid reservoir boat 24, and the reservoir connection boat 25,
It is in a state where fluid can be replenished from the fluid reservoir 20. When the brake pedal or clutch pedal is depressed, the bushing rod 49 pushes the first piston member 3 and the second piston member 4 to the left in the figure against the spring force of the compression coil springs 7 and 8. to move to the left. When the piston cup 43 passes through the orifice port 21 due to this movement, the first pressurizing chamber 14 is isolated from the fluid reservoir 20, and the internal pressure of the first pressurizing chamber 14 increases as the first piston member 3 moves.

Further, as the second piston member 4 moves to the left in the drawing, the rod 34 moves away from the stopper pin 23 to the left in the drawing, and the spring force of the compression coil spring 33 causes the valve element to
0 is displaced to the right in the figure relative to the second piston member 4, and when the second piston member 4 moves from the initial position to the left in the figure by a predetermined amount, the valve element 30 closes the valve with its rubber backing member 31. The user sits on the seat portion 32 and closes the valve. As a result, communication between the second pressurizing chamber 15 and the fluid reservoir boat 24 is cut off, and as the second piston member 4 moves to the left in the figure, the internal pressure of the second pressurizing chamber 15 increases. 1. The valve element 30, that is, the inlet valve, does not close until the second piston member 4 moves leftward by a predetermined amount from the initial position. During this period, the second pressurization chamber 15 is in communication with the reservoir communication chamber 17, and the fluid in the second pressurization chamber 15 escapes to the reservoir communication chamber 17, but the second pressurization chamber 15 and the reservoir communication chamber 1
7, the flow of fluid escaping from the second pressurizing chamber 15 to the reservoir communication chamber 17 is restricted due to the throttle hole 28 in the fluid flow path between the piston and the piston. In addition, a sudden rise in fluid pressure at the moment when the valve element 30 closes is avoided, and in addition, the dead stroke of the piston is reduced and responsiveness is improved.

When the brake pedal or the clutch pedal is released, the first piston member 3 and the second piston member 4 are returned to their initial positions as shown by the spring forces of the compression coil springs 7 and 8, respectively. At this time, the return of the fluid from the outlet boat 26 to the second pressurizing chamber 15 may be delayed due to flow path resistance, etc., and the second pressurizing chamber 15 may temporarily become in a negative pressure state. The water pushes open the valve element 30 and flows into the second boosting chamber 15, and also pushes open the piston cup 46 through the communication hole 48, so that it flows into the second boosting chamber 15. As a result, the second pressurization chamber 15 and the inlet valve chamber 2
7, the flow of the fluid described above is not obstructed, and the second pressurization chamber 15 is prevented from being in a large negative pressure state.

The fluid flowing into the second pressurizing chamber 15 at the initial stage of the piston return returns to the reservoir communication chamber 17 through the throttle passage hole 34 when the second piston member 4 returns to near the initial position and the valve element 30 opens. This prevents residual pressure from remaining for a long time when the pedal is released.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to these, and it is understood that various embodiments can be made within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment in which the portless type master cylinder device according to the present invention is applied as a tandem master cylinder device, and FIG. 2 is a schematic view of the portless type master cylinder device shown in FIG. 1. FIG. 1... Cylinder body, 2... Cylinder bore, 3.
...First piston member, 4...Second piston member, 5
．． 6... Retainer, 7.8... Compression coil spring, 9
...Stopper ring, 10-13...Piston land, 14...First pressurizing chamber, 15...Second pressurizing chamber, 1
6.17...Reservoir communication chamber, 18...Fluid reservoir port, 19...Reservoir connection port, 20.
... Fluid IJ f-bar, 21... Orifice port, 22... Long hole. 23... Stopper pin, 24... Fluid reservoir port, 25... Reservoir connection port, 26... Outlet port, 27... Inlet valve chamber, 2
8... Throttle hole, 29... Communication hole, 30... Valve element, 31... Rubber backing member, 32... Valve seat portion,
33... Compression coil spring, 34... Rod, 42~
46...Piston cup, 47.48...Communication hole,
49...Push rod

Claims (1)

[Claims] A pressurizing chamber having an outlet port is provided on one side of the piston member, and a reservoir communication chamber is provided on the other side,
A one-way seal structure is built into the piston member to prevent the flow of fluid from the pressurization chamber to the reservoir communication chamber and to allow the flow of fluid in the opposite direction, and when the piston member is in the initial position, the valve opens and the pressure increases. A portless master cylinder device having an inlet valve that communicates between the chamber and the reservoir communication chamber and closes when the piston member moves from the initial position to cut off communication between the pressurization chamber and the reservoir communication chamber. A portless master cylinder device, characterized in that a flow restriction means is provided in a communication passage connecting the inlet valve and the pressurizing chamber.