JPH0431899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to an improvement in a hydraulic pressure switching cylinder suitable for use in a brake device of a driving training vehicle or the like.

(Background of the Invention) This type of hydraulic pressure switching cylinder has been known, for example, from Publication of Utility Model Publication No. 52-48305 by the applicant of the present patent, and has already been used in the brake device of a driving training vehicle. ing.

FIG. 2 is a sectional view of the hydraulic pressure switching cylinder according to the above-mentioned prior art. In the example shown in FIG. 2, since a tandem type main master cylinder (not shown) corresponding to the first hydraulic pressure supply source is used, two hydraulic pressure switching cylinders 1, 1 having a similar structure are used. ' are arranged in parallel, and the two input ports 2,
2' and output ports 3, 3', respectively.
Furthermore, since a single system type single master cylinder is used as the auxiliary master cylinder (not shown) corresponding to the second hydraulic pressure supply source, a common input is provided to the two hydraulic pressure switching cylinders 1 and 1'. A port 4 is provided. The main master cylinder is operated by the trainee, and the auxiliary master cylinder is operated by the instructor.

A cylinder 5 is formed within the hydraulic pressure switching cylinder 1, and a hydraulic piston 6 is loaded so as to be movable back and forth. The hydraulic piston 6 divides the cylinder 5 into a first hydraulic chamber 7 that communicates with the input port 2 and the output port 3, and a second hydraulic chamber 8 that communicates with the input port 4. be done. 9, 10, 11 are communication holes, 1
2 is a nut screwed onto the open end of the cylinder 5.

The first hydraulic pressure chamber 7 is configured to move the hydraulic piston 6 away from the closed end 13 in the forward direction (rightward direction) by the hydraulic pressure of the auxiliary master cylinder supplied to the second hydraulic pressure chamber 8 through the input port 4. ), it will be compressed and
Further, the second hydraulic pressure chamber 8 is configured such that the moved hydraulic piston 6 is moved in the backward direction (to the left) by the hydraulic pressure of the main master cylinder supplied to the first hydraulic pressure chamber 7 through the input port 2. ), it is compressed.

The first hydraulic pressure chamber 7 has one end connected to the piston cap 1.
A known on-off valve 16 is installed, which engages with the valve cap 15 at its other end. The opening valve 1
6 is biased in the valve closing direction by the valve spring 17, is closed by moving the hydraulic piston 6 in the forward direction, and is opened by returning to the illustrated return position. 18 is a spring that urges the hydraulic piston 6 in the backward direction; 19 and 20 are seals attached to the hydraulic piston 6.

In the hydraulic pressure switching cylinder 1 described above, when the main master cylinder is driven by the trainee's depression of the main brake pedal, the input port 2, the communication hole 9, the first hydraulic chamber 7, the communication hole 10, and the output port Hydraulic pressure is supplied to the terminal brake device via 3. Furthermore, when the auxiliary master cylinder is driven by the instructor's depression of the auxiliary brake pedal, the hydraulic piston 6 is moved by the hydraulic pressure input into the second hydraulic chamber 8 through the input port 4 and the communication hole 11. It is pressed and moves forward, and at the same time as the on-off valve 16 is closed, the first
Due to the compression of the hydraulic chamber 7, hydraulic pressure is also supplied to the end brake device via the output port 3. Therefore, in a training vehicle equipped with the above-mentioned hydraulic pressure switching cylinder 1, the brakes can be operated independently from the trainee's side and the instructor's side to avoid danger. It has the advantage of being able to

However, during driving lessons,
Frequently, the instructor depresses the auxiliary brake pedal first, and then the trainee hurriedly depresses the main brake pedal. In such a case, if the conventional hydraulic pressure switching cylinder 1 described above is used, when the supply hydraulic pressure of the main master cylinder is higher than the supply hydraulic pressure of the auxiliary master cylinder, the hydraulic pressure of the main master cylinder will open the on-off valve 16. Since the valve is supplied to the first hydraulic pressure chamber 7 and the hydraulic piston 6 which is being moved in the forward direction is retreated,
Push-back hydraulic pressure is generated together with the auxiliary master cylinder to rapidly push back the auxiliary brake pedal, thereby expanding the volume of the first hydraulic pressure chamber 7 and increasing the depression of the main brake pedal. Therefore, there is a problem in that the pedal feel essential for brake control, that is, the appropriate pedal stroke, varies between the main brake pedal and the auxiliary brake pedal.

(Object of the Invention) The object of the present invention is to solve the above-mentioned problems and to apply push-back hydraulic pressure to the auxiliary master cylinder when the main master cylinder is operated while the auxiliary master cylinder is operating. It is an object of the present invention to provide a hydraulic pressure switching cylinder without any problems.

(Characteristics of the Invention) In order to achieve the above object, the present invention includes a hydraulic piston having a valve cylinder penetrating between a first hydraulic chamber and a second hydraulic chamber, and a main A valve rod is liquid-tightly mounted, the valve rod being moved in a backward direction relative to the hydraulic piston by input hydraulic pressure from a master cylinder and moved in a forward direction relative to the hydraulic piston by input hydraulic pressure from an auxiliary master cylinder; A first valve is provided at the end of the valve rod on the side of the first hydraulic pressure chamber to stop the flow of liquid from the first hydraulic chamber to the main master cylinder when the valve rod is moved in the forward direction. A second valve is provided at the chamber side end to suppress the flow of liquid from the second hydraulic pressure chamber to the auxiliary master cylinder when the cylinder is moved in the backward direction. When hydraulic pressure is input from the main master cylinder to the first hydraulic pressure chamber while the hydraulic piston and valve rod are moving forward, the valve rod moves back and prevents liquid from returning from the second hydraulic pressure chamber to the auxiliary master cylinder. It is characterized by suppressing, that is, cutting or squeezing.

(Embodiment of the invention) FIG. 1 is a sectional view showing an embodiment of the invention.

A driving training vehicle (not shown) is equipped with a main brake pedal 21 operated by a trainee from the driver's seat, and an auxiliary brake pedal 22 operated by an instructor from the passenger seat.

The main brake pedal 21 is a push rod 23.
and an auxiliary brake pedal 22 connected to a tandem master cylinder 25 via an auxiliary device 24.
Similarly, the push rod 26 and the assist device 27
It is connected to the single master cylinder 28 via.

Two output holes (not shown) of the tandem master cylinder 25 are connected to each other by conduits 29 and 29'.
Input ports 31 of the first hydraulic pressure switching cylinder 30 and the second hydraulic pressure switching cylinder 30' that are integrally formed;
31', respectively. The first and second hydraulic pressure switching cylinders 30 and 30' have similar structures and operate in the same manner.

The output port (not shown) of the single master cylinder 28 is connected by a conduit 32 to a common input port 33 of the first and second hydraulic pressure switching cylinders 30, 30'. The common input port 33 is communicated with the first hydraulic pressure switching cylinder 30 and the second hydraulic pressure switching cylinder 30', respectively, through input communication holes 34 and 35 which are branched.

In the first hydraulic pressure switching cylinder 30, a cylinder 39 is formed from the open end 37 side of the body 36 toward the closed end 38 side. 40 is a nut that seals the cylinder 39, and 41 is an input communication hole.

A hydraulic piston 42 is loaded into the cylinder 39 so as to be able to slide back and forth, and the hydraulic piston 42 has a first hydraulic chamber 43 on the open end 37 side and a second hydraulic chamber 44 on the closed end 38 side. It is formed. 45 and 46 are seals that come into sliding contact with the inner wall surface of the cylinder 39, and 47 is a return spring that urges the hydraulic piston 42 in the backward direction (to the left). The hydraulic piston 42 is
Normally, the return spring 47 presses against the stepped portion 48 formed on the closed end 38 side, and the illustrated return position is provided.

The hydraulic piston 42 is provided with a valve cylinder 49 formed coaxially with and penetrating the cylinder 39, and a valve rod 50 is inserted through the valve cylinder 49 so as to be movable back and forth. 51, 52
A seal 53 is in sliding contact with the outer peripheral surface of the valve rod 50, and a retainer 53 supports the seal 52.

A first valve 54 for opening and closing communication between the first hydraulic pressure chamber 43 and the input communication hole 41 is attached to the end of the valve rod 50 on the first hydraulic pressure chamber 43 side, and a first valve 54 is attached to the end of the valve rod 50 on the side of the second hydraulic pressure chamber 44. A second valve 55 that opens and closes communication between the second hydraulic pressure chamber 44 and the input communication hole 34 is formed in the section. 56 is an annular stopper fixed to the valve rod 50 by a circlip 57;
is a valve spring that urges the valve rod 50 in the forward direction (to the right) via the stopper 56. Normally, the stopper 56 is pressed against the second hydraulic chamber 44 side of the hydraulic piston 42 in the return position by the valve spring 58, thereby causing the valve rod 50 to close the first valve 54 and the second valve 54.
A neutral position is provided in which both valve 55 is opened.

59 is an output communication hole, 60 is an output port, 61 is a conduit, and 62 and 63 are rear wheel end brake devices. Similarly, on the hydraulic pressure switching cylinder 30' side, the output port 60' and the front wheel end brake devices 64, 65 are connected by a conduit 61'.

The operation of the embodiment shown in FIG. 1 will be explained below.

During a driving lesson, when the main brake pedal 21 is depressed by the trainee, the hydraulic pressure generated in the tandem master cylinder 25 is transferred to the conduits 29, 2.
9', to the input ports 31, 31' of the hydraulic pressure switching cylinders 30, 30', respectively, and from the respective output ports 60, 60' to the terminal brake devices 64, 65 on the front wheel side via conduits 61, 61'. It is supplied to the end brake devices 62 and 63 on the rear wheel side, and brake operation is performed.

During the brake operation as described above, the same hydraulic pressure as that of the terminal brake devices 62 and 63 is supplied to the first hydraulic chamber 43 of the hydraulic pressure switching cylinder 30, but the hydraulic pressure that is in pressure contact with the stepped portion 48 is The piston 42 is not moved in the backward direction (to the left), and only the valve rod 50 is moved until the communication hole 34 and the second hydraulic chamber 44 no longer communicate with each other. Since the expansion of the volume in the first hydraulic pressure chamber 43 due to the movement of the valve rod 50 is extremely small, the main brake pedal 21
There is no change in the amount of pedal effort, and appropriate braking operation can be performed.

The instructor will install the auxiliary brake pedal 2.
2 is depressed first, the hydraulic pressure generated in the single master cylinder 28 is supplied to the second hydraulic pressure chamber 44 via the conduit 32, the common input port 33, and the communication hole 34 (which communicates with the communication hole 35). (The second hydraulic pressure chamber on the hydraulic pressure switching cylinder 30' side is not shown).

Due to the hydraulic pressure supplied to the second hydraulic pressure chamber 44,
The hydraulic piston 42 is moved in the forward direction (to the right) from the illustrated return position against the return spring 47. Following this movement, the stopper 56
and the valve rod 50 are also moved in the same direction from the illustrated neutral position by the hydraulic pressure supplied to the second hydraulic pressure chamber 44 and the force of the valve spring 58, first the first valve 54 closes, and the first valve 54 closes. The outflow of liquid from the hydraulic pressure chamber 43 to the tandem master cylinder 25 is immediately cut off. After the first valve 54 is closed, the hydraulic piston 4
2 is advanced by the hydraulic pressure supplied to the second hydraulic chamber 44, and by compression of the first hydraulic chamber 43, the terminal brake device 6 on the rear wheel side connected to the output port 60 is moved forward by the hydraulic pressure supplied to the second hydraulic chamber 44.
2,63 is operated. This operation is performed in the same way in the hydraulic pressure switching cylinder 30', and the end brake device 6 on the front wheel side connected to the output port 60'
4,65 will also be operated.

During the above operation, when the main brake pedal 21 is depressed by the trainee and a hydraulic pressure greater than that of the single master cylinder 28 is supplied from the tandem master cylinder 25 to each input port 31, 31', the first The valve 54 is opened, and the hydraulic pressure in the first hydraulic pressure chamber 43 becomes larger than the hydraulic pressure in the second hydraulic pressure chamber 44 (the first hydraulic pressure switching cylinder 30' side
valves not shown).

The above-mentioned hydraulic pressure in the first hydraulic pressure chamber 43 is applied to the hydraulic piston 4
2 to move the valve rod 50 in the backward direction (to the left), but the valve rod 50
When the hydraulic piston 42 moves backward, the second valve 55 is closed and the flow of liquid from the second hydraulic pressure chamber 44 to the communication hole 34 is immediately cut off. Reducing the volume of the pressure chamber 44 and reducing the first hydraulic pressure chamber 43
The volume expansion of is stopped. Therefore, an increase in the amount of depression of the main brake pedal 21 connected to the first hydraulic pressure chamber 43 and a push back of the auxiliary brake pedal 22 connected to the second hydraulic pressure chamber 44 are prevented.

(Correspondence between the invention and the embodiments) The tandem master cylinder 25 shown in FIG. 1 corresponds to the main master cylinder of the present invention, and the single master cylinder 28 corresponds to the auxiliary master cylinder.

(Modification) In the embodiment shown in FIG. 1, the dual hydraulic pressure switching cylinders 30, 30' are arranged in parallel, but they may be arranged coaxially on the left and right from the common input port 33. , and if both the main master cylinder and the auxiliary master cylinder are of the same type,
A single hydraulic pressure switching cylinder 30 is used.

When the second valve 55 is closed, the second hydraulic pressure chamber 44
Although the flow of the liquid from the to the communication hole 34 is cut off, a valve that operates to throttle the flow of the liquid may also be used. In this case, since the auxiliary brake pedal 22 is pushed back slowly, the depression force on the auxiliary brake pedal 22 can be adjusted while sensing the degree to which the main brake pedal 21 is depressed.

(Effects of the Invention) As described above, according to the present invention, the hydraulic piston is formed with a valve cylinder that penetrates between the first hydraulic pressure chamber and the second hydraulic pressure chamber, and the valve cylinder is provided with a second hydraulic pressure chamber. 1. A valve rod is fluid-tightly mounted so that the valve rod is moved in a backward direction relative to the hydraulic piston by input hydraulic pressure from a hydraulic pressure supply source, and is moved in a forward direction relative to the hydraulic piston by input hydraulic pressure from an auxiliary master cylinder. A first valve is provided at the end of the valve rod on the side of the first hydraulic pressure chamber, and a first valve is provided to stop the flow of liquid from the first hydraulic pressure chamber to the main master cylinder when the valve rod is moved in the forward direction. A second valve is provided at the end of the hydraulic pressure chamber that suppresses the flow of liquid from the second hydraulic chamber to the auxiliary master cylinder when the cylinder is moved in the backward direction. When the master cylinder is operated, it is possible to prevent the generation of pushback hydraulic pressure acting on the auxiliary master cylinder.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a sectional view showing a conventional example. 21...Main brake pedal, 22...Auxiliary brake pedal, 25...Tandem master cylinder, 28...Single master cylinder, 30,
30'...Liquid pressure switching cylinder, 31, 31'...
Input port, 33...Common input port, 36...Body,
39...Cylinder, 42...Hydraulic piston, 43
...First hydraulic pressure chamber, 44...Second hydraulic pressure chamber, 45,4
6...Seal, 47...Return spring, 4
9... Valve cylinder, 50... Valve rod,
51, 52... Seal, 54... First valve, 55...
...Second valve, 56...Stopper, 58...Valve spring, 60, 60'...Output port, 62, 63,
64, 65...Terminal brake device.

Claims (1)

[Claims] 1 A first hydraulic pressure chamber connected to the main master cylinder for input, a second hydraulic chamber connected for input to the auxiliary master cylinder, and a hydraulic pressure chamber in the first hydraulic pressure chamber and the second hydraulic pressure chamber. A hydraulic pressure switching cylinder is provided with a hydraulic piston that receives pressure from the front and rear, and has an output port connected to a terminal brake device in the first hydraulic pressure chamber, wherein the hydraulic piston is connected to the first hydraulic pressure chamber. A valve cylinder penetrating between the second hydraulic pressure chambers is formed, and the valve cylinder is moved in a backward direction relative to the hydraulic piston by input hydraulic pressure from the main master cylinder, and receives input liquid from the auxiliary master cylinder. A valve rod that is moved in the forward direction relative to the hydraulic piston by pressure is fluid-tightly loaded, and when the valve rod is moved in the forward direction, the end portion of the valve rod on the first hydraulic pressure chamber side is moved from the first hydraulic pressure chamber. A first valve is provided at the end on the second hydraulic pressure chamber side to stop the flow of liquid to the main master cylinder, and when the valve is moved in the backward direction, the flow of liquid from the second hydraulic chamber to the auxiliary master cylinder is provided. A hydraulic pressure switching cylinder characterized by being provided with a second valve that suppresses flow.