JPH0412845Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention is designed to connect a main master cylinder, an auxiliary master cylinder, and a slave cylinder so that at least one of the main master cylinder and the auxiliary master cylinder can be artificially The present invention relates to a switching cylinder that operates a slave cylinder when activated, and is used, for example, in a brake system for a training vehicle.

(Prior art) Conventionally, as this type of switching cylinder,
Some of these are shown in Japanese Utility Model Publication No.-48305 and Japanese Utility Model Application Publication No. 57-6663. This has a main inlet port connected to the main master cylinder, an auxiliary inlet port connected to the auxiliary master cylinder, and an outlet port connected to the slave cylinder, and an inner hole through which each of these ports communicates. a first chamber which is slidably assembled in the inner hole of the cylinder body in the axial direction and communicates with the main inlet port and the outlet port; A piston is divided into a second chamber with which an auxiliary inlet port communicates, and an annular projection is formed at the end on the side of the first chamber, and a valve is fitted into the annular projection of the piston and is disposed within the annular projection. a holder that forms a chamber and has a communication hole that communicates the valve chamber and the first chamber in the axial direction; a spring disposed within the valve chamber and cooperating with the piston to move the piston from its original position to the first position;
It is provided with an on-off valve that allows liquid to flow from the main inlet port to the outlet port and blocks communication between these two ports when the main inlet port moves a predetermined amount toward the chamber.

(Problem to be solved by the invention) By the way, in the conventional switching cylinder, when the piston is in its original position, communication from the main inlet port to the outlet port is through the on-off valve and the axial communication hole in the holder. When the piston is moved by a predetermined amount by the pressure fluid of the main master cylinder or the pressure fluid supplied from the auxiliary master cylinder to the second chamber to increase the fluid pressure in the first chamber, the hydraulic fluid flows into the holder. The hydraulic fluid flows through the axial communication hole of the piston, and there is no operation of the hydraulic fluid around the outer circumference of the annular protrusion of the piston, which is almost stationary. Therefore, in conventional switching cylinders, depending on how the switching cylinder is installed on the vehicle, when the switching cylinder is operated, air bubbles generated in the hydraulic fluid may accumulate around the annular protrusion of the piston, causing air to bleed. However, since the hydraulic fluid does not flow around the outside of the annular protrusion of the piston, it remains.Furthermore, foreign matter in the hydraulic fluid may accumulate near the on-off valve, reducing the sealing performance of the on-off valve. There was a problem that it caused problems such as insufficient power.

Therefore, the technical problem of the present invention is to prevent air bubbles in the hydraulic fluid generated when the switching cylinder is operated from remaining around the outside of the annular protrusion of the piston.

[Structure of the idea]

(Means for solving the problem) The technical means taken to solve the above-mentioned technical problem is that the valve chamber and the first chamber are arranged around the outer circumference of the annular protrusion of the piston near the annular protrusion of the piston. A communication path is provided between the main inlet port and the first chamber to guide the liquid flow from the main inlet port to the outer circumference of the annular protrusion of the piston.

(Function) As a result, even if the switching cylinder is installed with its axial direction horizontal to the vehicle, the liquid flow from the main inlet port to the first chamber is guided to the outer circumference of the annular protrusion of the piston. Air bubbles in the hydraulic fluid will not remain around the outside of the annular protrusion, and even if the switching cylinder is installed with its axis vertical to the vehicle, foreign matter in the hydraulic fluid will be removed from the valve chamber by the annular protrusion of the piston. Since the fluid flows into the first chamber through the communication path provided near the opening/closing valve, foreign matter does not remain near the on-off valve. Therefore, it is possible to eliminate problems caused by foreign objects staying near the on-off valve and air bubbles remaining around the outer circumference of the annular protrusion of the piston (the above-mentioned insufficient braking force).

(Embodiment) An embodiment of the switching cylinder according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example in which the present invention is applied to a brake hydraulic system for a training vehicle, in which the main master cylinder 10 is integrated with a brake booster 11 and a brake pedal
A tandem master cylinder operated by a brake pedal 15 is employed as the auxiliary master cylinder 13, and a single cylinder operated by a brake pedal 15 separately from a brake booster 14 is employed. Also, first and second main inlet ports 20a and 20b are connected to the pressure chambers 10a and 10b of the main master cylinder 10 as the switching cylinder A, respectively.
, the auxiliary inlet port 20c connected to the pressure chamber 13a of the auxiliary master cylinder 13, and the first and A two-system switching cylinder having second outlet ports 20d and 20e is employed. In addition, the main master cylinder 10, brake booster 11, auxiliary master cylinder 13, brake booster 14, rear and front wheel cylinders 16, 16, 1
The configurations of 7, 17, etc. are publicly known.

The switching cylinder A is connected to each of the above-mentioned ports 20a to 20a.
20e, and each port 20a, 20
Inner hole 20f and each port 20 with which c and 20d communicate
Inner hole 20g and both inner holes 20 where d and 20d communicate
Communication hole 20 that connects the right end of f, 20g in the drawing
The cylinder body 20 includes a cylinder body 20 having a diameter h, pistons 31 and 41 assembled in the cylinder body 20, on-off valves Va and Vb, and a control valve Vo.

Each piston 31, 41 has piston cups 39a to 39c, 49 fitted at three locations on its outer periphery, respectively.
Inner hole 20 of cylinder body 20 by a to 49c
The first chambers R11, R21 and the second chambers R12, R22 are installed in the inner holes 20f, 20g so as to be slidable in the axial direction in a fluid-tight manner.
(They communicate with each other through the communication hole 20h.) The springs S11 and S21 urge the second chambers R12 and R22 to elastically fix the chambers at the original position shown in the figure. ing. Each piston 31, 41 also has a main inlet port 20.
annular grooves 31a, 41a communicating with a, 20b are formed, respectively, and each annular groove 31a, 41a
Cross-shaped communication holes 31c and 41c are formed to communicate with the first chambers R11 and R21 and the left ends of the inner holes 31b and 41b provided in the axis, respectively, and the right ends of the inner holes 31b and 41b are formed respectively. The cylindrical plugs 33, 43 are inserted through the gaskets 32, 42 into the parts.
are assembled airtightly and liquidtightly, and each inner hole 31
b, 41b have plungers 34, 44, rod 3
5 and 45 and springs S12 and S22 are assembled, respectively. Further, annular protrusions 31g, 41g are formed at the left ends of the pistons 31, 41 in the drawing, and several communicating passages 31f, 41f are provided radially in the annular protrusions 31g, 41g.

Each plunger 34, 44 has each inner hole 31b, 4
Each inner hole 31b, 41b is assembled slidably in the axial direction in an airtight and liquidtight manner.
There are third chambers R13, R23 and air chambers R14, R2 inside.
4 respectively. Each rod 35, 45
is urged to the left in the figure by springs S12 and S22, and is in contact with each plunger 34 and 44, and the right end in the figure is slidable in the axial direction to each plug 33 and 43, and is airtight and liquid-tight. They are tightly assembled and protrude into each of the second chambers R12 and R22.

Each on-off valve Va, Vb is connected to each first chamber R11, R21.
The annular protrusions 31g and 4 of each piston 31 and 41 open and close the communication between the communication holes 31c and 41c.
Valve chambers Rv ₁ and Rv ₂ formed by the holders 36 and 46 fitted to the holders 36 and 46 (the first chambers R11 and R21 are connected to each other by several axial communication holes 36a and 46a provided in the holders 36 and 46) The plugs 21 and 2, which form part of the cylinder body 20, are disposed in the holders 36 and 46 so as to be slidable in the axial direction.
2 or regulated by retainers 37, 47, and the left end in the figure is connected to holders 36, 4.
6 and urges the valve bodies 38, 48 to the right in the figure, and each piston 3.
It is constituted by valve seats 31e and 41e formed at step portions 1 and 41 on which valve bodies 38 and 48 can be seated.

In addition, in a passage that communicates the second chamber R12 and the auxiliary inlet port 20c at the lower part of the figure, that is, in the plug 23 that constitutes a part of the cylinder body 20, the second chamber R12 and the auxiliary inlet port 20c are normally connected.
The auxiliary inlet port 20 operates when pressurized fluid is supplied to the first chamber R11 by the operation of the main master cylinder 10.
A control valve Vo is interposed to allow liquid flow from the auxiliary inlet port 20c to the second chamber R12 and to restrict communication between the auxiliary inlet port 20c and the second chamber R12. In this embodiment, detailed explanation of the control valve Vo will be omitted.

The operation of this embodiment having the above configuration will be explained.

When only the brake pedal 12 is depressed, pressure fluid is supplied from the pressure chamber 10a of the main master cylinder 10 to the first main inlet port 20a of the switching cylinder A, and at the same time, pressure fluid is supplied from the pressure chamber 10b of the main master cylinder 10 to the switching cylinder A. Pressure fluid is supplied to the second main inlet port 20b. However,
At this time, in the switching cylinder A, the third chamber R13 is passed from the first main inlet port 20a to the annular groove 31a of the piston 31 and the communication hole 31c.
The plunger 34 and the rod 35 are pushed to the right in the figure against the spring S12 by the pressure fluid flowing into the valve, and although the control valve Vo operates, the other members do not move as shown. For this reason,
The pressure fluid supplied to the first main inlet port 20a flows through the annular groove 31a of the piston 31 and the communication hole 31c.
The piston 31,
41 through the communication passages 31f, 41f provided in the annular protrusions 31g, 41g and the axial communication holes 36a, 46a of the holders 36, 46, the first
It is supplied to the chamber R11, and is further supplied to both rear wheel cylinders 16, 16 from the first outlet port 20d.
supplied to. On the other hand, the pressure fluid supplied to the second main inlet port 20b is connected to the annular groove 41a of the piston 41 and the communication hole 41c, and the on-off valve that is in the open state.
Annular protrusion 31 of piston 31, 41 through Vb
Communication passages 31f, 41f provided in g, 41g and axial communication holes 36a, 4 of holders 36, 46
6a to the first chamber R21 in the upper part of the drawing, and further supplied to both front wheel cylinders 17, 17 from the second outlet port 20e.

In this state, when the brake pedal 15 is depressed and a higher pressure fluid is supplied to the auxiliary inlet port 20c than the fluid being supplied to both the main inlet ports 20a and 20b, the same pressure fluid flows into the lower part of the figure. The liquid is supplied to the second chamber R12 shown in the lower part of the figure through the control valve Vo that allows liquid to flow to the second chamber R12, and from the second chamber R12 to the communication hole 20h.
It is supplied to the second chamber R22 in the upper part of the figure through the air.
For this reason, each piston 31, 41 is connected to each second chamber R1.
2, R22 is pushed to the left in the figure by the pressing force of the internal hydraulic pressure against the pressing force of each spring S11, S21 and the respective first chambers R11, R21 internal hydraulic pressure. When each piston 31, 41 is pushed from its original position to the left in the drawing by a predetermined amount, the valve seats 31e, 41e formed on each piston 31, 41, each retainer 37, 47, and each spring S13, S
23, the valve bodies 38, 48 held at the positions shown come into contact with each other, and the on-off valves Va, Vb are closed. Therefore, thereafter, each second
The hydraulic pressure in the chambers R12 and R22 is
1 to the respective first chambers R11, R21, and the same hydraulic pressure is transmitted to the rear wheel cylinders 16, 16 and the front wheel cylinders 17, 17 through the respective outlet ports 20d, 20e. Note that when each of the pistons 31, 41 described above is pushed from the original position shown in the figure by a predetermined amount to the left in the figure, an amount of pressurized fluid corresponding to the amount of movement of each piston 31, 41 flows into each main inlet port 20a, 20b. is returned to each pressure chamber 10a, 10b of the main master cylinder 10,
The amount is as shown in each valve body 38, 48 and valve seat 31.
Since it corresponds to the distance between e and 41e (lift amount of the valve body) and is small, no problem occurs.

Further, in this embodiment, when only the brake pedal 15 is depressed, the auxiliary master cylinder 1
Pressure fluid is supplied from the pressure chamber 13a of No. 3 to the auxiliary inlet port 20c of the switching cylinder A via the booster 14. At this time, since all the members in the switching cylinder A are in the positions shown in the figure, the pressure fluid supplied to the auxiliary inlet port 20c passes through the control valve Vo, which allows free flow, to the second chamber R12 in the lower part of the figure. In addition to being supplied to
It is supplied from the second chamber R12 to the second chamber R22 in the upper part of the figure through the communication hole 20h. Therefore, each piston 31, 41 is connected to each spring S11, S21.
The on-off valves Va, Vb are pushed to the left in the figure against the
is closed, and the subsequent movement of each piston 31, 41 to the left in the figure causes pressure to flow from each first chamber R11, R21 to rear wheel cylinders 16, 16 and front wheel cylinders 17, 17 through each outlet port 20d, 20e. liquid is supplied.

As described above, in this embodiment, the piston 3
When the switching cylinder A is operated, the hydraulic fluid is transferred from the valve chambers Rv ₁ and Rv ₂ to the
Since the flow also flows around the outer circumferences of the annular protrusions 31g and 41g of the pistons 31 and 41 in the chambers R ₁₁ and R ₂₁ , even if the switching cylinder A is installed with its axial direction horizontal to the vehicle, the hydraulic fluid will not flow during operation. The air bubbles generated therein will not remain around the outer periphery of the annular protrusions 31g, 41g, and the braking force will not be insufficient due to the air bubbles remaining. Furthermore, in this embodiment, even if the switching cylinder A is installed with its axial direction perpendicular to the vehicle, foreign matter in the hydraulic fluid will not be present in the valve chambers Rv ₁ ,
From Rv ₂ , go through the communication passages 31f and 41f and enter the 1st room.
Since the flow flows into R ₁₁ and R ₂₁ , foreign matter does not accumulate near the on-off valves Va and Vb.
There is no possibility of insufficient control power due to malfunction of Va or Vb.

As described above, in this embodiment, the pistons 31, 41
Valve chambers Rv ₁ and Rv ₂ are provided in the annular protrusions 31g and 41g.
From the annular protrusions 31g and 41 in the first chambers R ₁₁ and R ₂₁
g radial communication path 31f that communicates around the outer periphery;
41f is provided _, but as shown in _FIG .
A groove may be provided from the end face to the outer periphery so as to communicate the periphery of the outer periphery, and a communication path 41h may be formed by the gap formed between the holders 36 and 46. Similarly, as shown in FIG. holder 36,
46 pistons 31, 41 annular projections 31g, 4
Grooves are provided at several places on the fitting surface between the valve chambers Rv ₁ and Rv ₂ to the outer periphery of the annular protrusions 31g and 41g, and gaps are formed between the annular protrusions 31g and 41g. The communication path 46b may be formed by. In FIGS. 2 and 3, the same members as those in FIG. 1 are designated by the same numbers, and both figures show an example in which the piston 41 shown in the upper part of FIG. 1 is used.

[Effect of idea]

According to the present invention, insufficient braking force caused by air bubbles in the hydraulic fluid remaining around the outer periphery of the annular protrusion of the piston and foreign matter in the hydraulic fluid retained near the on-off valve can be reduced by applying the switching cylinder to the vehicle. This can be reliably resolved without any restrictions on installation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a switching cylinder according to the present invention used in a brake hydraulic system for a training vehicle, and FIGS. 2 and 3 are cross-sectional views showing other embodiments of the present invention. 10... Main master cylinder, 13... Auxiliary master cylinder, 16, 17... Slave cylinder,
20...Cylinder body, 20a, 20b...Main inlet port, 20c...Auxiliary inlet port, 20d, 20e...Outlet port,
20f, 20g... Inner hole, 31, 41... Piston, 31f, 41f... Communication path, 31g, 41g
...Annular protrusion, 41h...Communication path, 36, 46...
...Holder, 46b...Communication path, A...Switching cylinder, _S11 , _S21 ...Spring, _R11 , _R21 ...First
Chamber, R ₂₁ , R ₂₂ ...Second chamber, Va, Vb...Opening/closing valve,
Chambers Rv ₁ , Rv ₂ ...Valve chambers.

Claims (1)

[Scope of utility model registration request] A cylinder that has a main inlet port connected to the main master cylinder, an auxiliary inlet port connected to the auxiliary master cylinder, and an outlet port connected to the slave cylinder, and has an inner hole through which each port communicates. a first chamber that is slidably assembled in the inner hole of the cylinder body in the axial direction and communicates with the main inlet port and the outlet port; and the auxiliary inlet port. a piston partitioned into a communicating second chamber and having an annular protrusion formed at its first chamber side end; a piston fitted into the annular protrusion of the piston to form a valve chamber within the annular protrusion; a holder having a communication hole that communicates the valve chamber and the first chamber in the axial direction; a spring that is stretched in the first chamber and biases the piston toward the second chamber through the holder; Disposed within the valve chamber and linked to the piston so that the main inlet port and outlet port communicate with each other when the piston is in the original position, and the piston moves a predetermined amount from the original position toward the first chamber. In a switching cylinder equipped with an on-off valve that allows liquid to flow from the main inlet port to the outlet port and blocks communication between these two ports when A communication passage communicating between the valve chamber and the outer periphery of the piston annular protrusion of the first chamber is provided, and a liquid flow from the main inlet port to the first chamber is guided to the outer periphery of the annular protrusion. Features a switching cylinder.