JPH0356438Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a brake device, and particularly relates to a brake device that is used as an auxiliary brake device when parking or stopping on a slope or slope. The present invention relates to effective brake systems for use in vehicles equipped with working machines.

[Conventional technology]

2. Description of the Related Art In recent years, vehicles equipped with working machines such as construction-related machines have become increasingly larger. For this reason, there is a concern that when parking a vehicle on a slope or slope at a work site such as a construction site, the braking force of the vehicle's normal parking brake may not be sufficient.

In such cases, countermeasures such as putting wheel chocks in place are taken, but not only does it take time and effort to change the parking/parking position, but there are still problems in terms of safety measures.

On the other hand, as a brake device for such a vehicle equipped with a large working machine, there is one in which the service brake is equipped with a hydraulic brake booster, as shown in FIG.

In Fig. 5, 1 is a hydraulic brake booster;
2 is a main pump unit that is driven by the engine E and supplies hydraulic pressure to the hydraulic brake booster 1; 3 is a reservoir tank; 4 is an electric pump that doubles the hydraulic brake when the oil supply system of the main pump unit 2 breaks down. The power device 1 is configured to supply hydraulic pressure. A flow switch 5 is configured to detect a failure in the main pump unit 2 system and operate the electric pump 4. 6 is a brake pedal, and when the pedal is depressed, the hydraulic brake booster 1 is activated. Reference numeral 7 denotes a brake actuation device consisting of a master cylinder, a wheel cylinder, a drum brake, etc., and is configured to be actuated by the hydraulic brake booster 1.

In a brake system for a vehicle equipped with a large working machine equipped with such a brake booster, when parking or stopping on a slope or slope as described above, the hydraulic brake booster 1 is activated by stepping on the brake pedal 6.
All you have to do is activate it.

[Problem that the invention attempts to solve]

However, in a brake device equipped with such a hydraulic brake booster, the operator must continue to press the brake pedal while the machine is parked, and the engine output is not sufficient to operate the machine. There is a problem that it cannot be used when the engine is in use or when the engine is stopped.

Furthermore, not all types of large vehicles require a brake system that utilizes such a brake booster.

Therefore, if such a brake device can be appropriately attached to a necessary vehicle, it will be extremely advantageous in terms of production of vehicle brake devices.

An object of the present invention is to provide a brake device that can automatically operate a brake booster when desired.

[Means for solving problems]

The brake device according to the present invention includes a brake booster 8 that operates the brake actuating device 7, and the brake booster 8 is slidably fitted into the cylinder 11 and is moved forward. Power piston 14 that generates braking force
and a plunger 2 that moves the power piston 14 forward by generating a pressure difference between the fluid supply side and the fluid discharge side of the power piston 14 in the cylinder 11 by moving forward according to the depression of the brake pedal 9.
2, and a pump unit 2 that is driven by the engine E and supplies fluid to the cylinder 11 during normal times.
and an electric pump 40 that supplies fluid to the cylinder 11 during non-normal times, the brake booster 8 includes a cylinder device 42,
42A is provided, and this cylinder device 4
2, 42A is configured to advance the plunger 22 by the output of the electric pump 40 when specified, and is configured in a cartridge type so that it can be attached to any brake booster 8. do.

[Effect]

The cylinder devices 42 and 42A, which are configured in a cartridge type, are brake boosters 8 for use in vehicles equipped with working machines that require strong auxiliary braking force.
It will be attached to.

In the brake device 8 to which the cylinder devices 42 and 42A are attached, the electric pump 40 is activated and pressure is applied to the cylinder device 42 when a parking brake or the like is applied.
When the plunger 22 is moved forward by the cylinder device 42, the power piston 14 of the brake booster 8 sends out hydraulic pressure, so the brake actuating device 7 is activated, and the brake state of the large vehicle when parking or stopping is activated. will be created.

〔Example〕

FIG. 1 is a hydraulic circuit diagram showing a brake device according to an embodiment of the present invention, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is a longitudinal sectional view thereof.

In this embodiment, the brake system includes a brake booster 8, to which an oil pump unit 2 is connected. The oil pump unit 2 is equipped with an oil pump 2a driven by the vehicle's engine E, and the oil pump 2a is designed to force-feed oil from a reservoir tank 3 to a brake booster 8 via a throttle valve 2b. . This unit 2 is provided with a relief valve 2c via a second throttle valve 2d.

In this embodiment, the brake booster 8 includes a cylinder 11, and a supply path 12 connected to the oil pump unit 2 at one end (hereinafter referred to as the rear side) of the cylinder 11. Similarly, a discharge passage 13 is provided at the front end of the cylinder 11 so as to supply pressure oil to the inside of the cylinder 11, and to discharge pressure oil from the inside of the cylinder 11.

A power piston 14 is fitted between the supply passage 12 and the discharge passage 13 inside the cylinder 11 so as to be slidable in the front-rear direction, and a push rod 15 is arranged on the power piston 14 so that their center lines substantially coincide with each other. At the same time, the rear end portions are fitted and connected. A plurality of passages 16 are opened around the axis of the power piston 14 so as to connect a first chamber 17 and a second chamber 18 on both sides of the power piston 14. A valve plate 19 is fitted at the rear position and arranged substantially perpendicular to the axis. A valve port 20 is concentrically opened in the valve plate 19, and the valve port 20 communicates with a first chamber 17 and a second chamber 18 on both sides of the power piston 14 via a passage 16. There is. A valve seat 21 is cut into the rear opening edge of the valve port 20, and the valve seat 21 is formed in a female tapered shape that widens at the rear.

Plungers 22 are arranged on the rear end wall of the cylinder 11 so that their center lines substantially coincide with each other, and their front ends are inserted into the interior of the cylinder 11.
It is supported so as to be slidable in the front-rear direction. A brake rod 24 interlocked with the brake pedal 9 is connected to the rear end of the plunger 22 so as to butt against each other, and the brake rod 24 and the cylinder 11
A boot 25 is stretched between the ends of the plunger 22 so as to cover the outside of the plunger 22.

A valve portion 26 is cut at the front end of the plunger 22 so as to face the valve port 20 in the first chamber 17 of the cylinder 11, and the valve portion 26 has a male taper shape that substantially corresponds to the female taper shape of the valve seat 21. It is formed. A check valve 27 is incorporated inside the front end of the plunger 22.
7 is configured to open only from the second chamber 18 side communicating with the discharge path 13 to the first chamber 17 side communicating with the supply path 2.

A reaction spring 28 is disposed outwardly at the front end of the plunger 22, and this spring 28 has its front end connected to the power piston 14.
The valve plate 19 is pressed against a spring receiver 29 whose rear end is engaged with a protrusion 30 on the outer periphery of the plunger 22 in a stored force state. This spring 28 causes the plunger 22
This means that the power piston 19 and the power piston 19 are always urged in the direction of separating from each other.

Further outward of the reaction spring 28 at the front end of the plunger 22, a sleeve 31 as a position regulating means is disposed concentrically, and a plurality of through holes 32 are provided in the body of the sleeve 31 to communicate the inside and outside. It has been established to allow The sleeve 31 is fixedly supported by the power piston 14 by being locked with a snap spring 33 at its front end, and its rear end abuts on a protrusion 30 protruding from the outer periphery of the plunger 22 so as to be removable from the rear. It is configured as follows. That is, although the sleeve 31 allows the plunger 22 to move back and forth,
The plunger 22 is configured to limit the distance in the direction in which the plunger 22 moves away from the power piston 14.
The regulation value of the interval by the sleeve 31 is set to be approximately equal to the initial clearance C between the valve seat 21 and the valve portion 26.

On the other hand, in the second chamber 18 in the cylinder 11, a return spring 34 is interposed in a stored state between the power piston 14 and an end plate 35 fitted into the front end face opening of the cylinder 11. The power piston 14 is always urged rearward by the spring 34.

A master cylinder 36 is provided on the front end surface of the cylinder 11.
are fixedly connected to each other so that their center lines substantially coincide with each other, and the piston 37 of the master cylinder 36
The front end of the push rod 15, which is connected to the power piston 14, passes through an end plate 35 and abuts against it.

A detour path 38 is provided in the cylinder 11 to bypass the valve port 20 so as to communicate between the supply path 12 and the discharge path 13, and a relief valve 39 is provided in the detour path 38.

An electric pump 40 is connected to the cylinder 11, and the electric pump 40 is configured to circulate oil in the reservoir tank 3 to the first chamber 17 and the second chamber 18 of the cylinder 11. Further, the cylinder 11 is equipped with a flow switch 41, and this switch 41 is connected to the main pump unit 2.
When pressure oil is being circulated to the first chamber 17 and second chamber 18, it is turned OFF, and when a failure occurs in the oil supply system of the main pump unit 2, etc.
The electric pump 40 is configured to be turned on to operate the electric pump 40.

The brake device for a vehicle equipped with a large working machine configured as described above includes the cylinder 11.
For example, a cylinder device (hereinafter referred to as an auxiliary cylinder device) that is used auxiliary when parking or stopping on a slope or slope is installed at the end of the plunger 22 side of the plunger 22.
42 is incorporated, and the auxiliary cylinder device 42 is configured in a cartridge type. That is, the auxiliary cylinder device 42 has a main body 42a in which a cylinder chamber 43 surrounding the rear end of the plunger 22 is formed.
The main body 42a is screwed onto the rear end of the plunger 22 in the cylinder 11. An auxiliary piston part 44 is integrally molded in a stepped shape at the rear end of the plunger 22 in the cylinder chamber 43, and the plunger 22 is configured as a cartridge type by being separate from the power piston 14 and push rod 15. has been done.

A fuel filler port 45 is provided in the cylinder chamber 43 at a position facing the rear end surface of the auxiliary piston portion 44 . An auxiliary hydraulic circuit 46 is connected to the oil supply port 45 , and this circuit 46 is connected to the discharge side of the electric pump 40 via an electromagnetic switching valve 47 .
This auxiliary hydraulic circuit 46 is also configured to be detachable from the electric pump 40, so that it is of a cartridge type. The electromagnetic switching valve 47 is configured to be switched at a predetermined time to be described later to supply pressure oil from the electric pump 40 to the cylinder chamber 43 of the auxiliary cylinder device 42, and to discharge pressure oil from the cylinder chamber 43 at other times. ing.

Note that 48 is a pressure switch, which is configured to stop the electric pump 40 when the pressure in the auxiliary hydraulic circuit 46 exceeds a set value, thereby preventing seizure accidents. 49,50
51 is a check valve, and 51 is a throttle valve, which ensures the advance of the plunger 22 by the auxiliary cylinder device 42 by making the oil pressure value in the cylinder chamber 43 of the auxiliary cylinder device 42 slightly higher than the oil pressure value in the first chamber 17 of the cylinder 11. I try to do that. 52 is a parking switch, and 53 is a switch for operating the auxiliary cylinder device, which is linked to, for example, the parking switch 52, and is turned on when the auxiliary cylinder device 42 is to be activated when parking on a slope or slope. , and is configured to substantially command braking using a brake booster. 54 is a relay coil, and 55 is a relay switch.

Next, the effect will be explained.

When the brake is not activated, the valve portion 26 of the plunger 22 faces the valve port 20 of the power piston 14 with a preset initial distance C therebetween.

In this state, the pressure oil supplied from the oil pump unit 2 to the first chamber 17 via the supply port 12 by the drive of the engine E is supplied to the valve port 20,
It flows into the second chamber 18 through the passage 16 and the discharge passage 1
By discharging from 3, it circulates inside the cylinder 11.

Next, when the brake pedal is depressed and the brake rod 24 is pushed, the power piston 14
is strongly urged rearward by the return spring 34, so the plunger 22 moves forward against the reaction 28 so as to approach the power piston 14.

As the plunger 22 approaches the power piston 14, the valve part 26 narrows the valve port 20, so a pressure difference is generated between the first chamber 17 and the second chamber 18 on both sides of the power piston 14. As a result, the power piston 14 is moved forward strongly. If the brake pedal continues to be depressed, the valve portion 26 will continue to repeatedly throttle the valve port 20, so the power piston 14 will actuate the brake by pushing the piston 37 of the master cylinder 36 via the push rod 15. It will be possible to

At this time, the engine E causes the oil pump 2a to
As long as the flow switch 41 is driven and pressure oil is supplied from the oil pump unit 2 to the first chamber 17, the flow switch 41 maintains the OFF state by detecting pressure oil. Therefore, the electric pump 40 remains in a stopped state.

For some reason, oil pump unit 2
When the supply of oil to the first chamber 17 is stopped, the flow switch 41 detects this and
It becomes ON state. Since the electric pump 40 is activated by turning on the switch 41, pressurized oil is supplied to the first chamber 17 by the electric pump 40. Therefore, even if a failure should occur in the oil pump unit 2 or the like, pressurized oil to the first chamber 17 is ensured, brake operation is ensured, and safety is maintained.

By the way, as mentioned above, in a large vehicle equipped with the cartridge type auxiliary cylinder device 42, when parking or stopping on a slope or slope, the brake booster 8 is automatically activated without depressing the brake pedal. If you want to activate the brake and leave it on, when the parking switch 52 is turned on, the brake booster switch 53 is turned on.
As a result, the electromagnetic switching valve 47 is switched. At this time, since the pressure switch 48 is on, the relay coil 54 is excited and the relay switch 55 is turned on. As a result, the electric pump 40
is operated, and pressure oil is supplied to the cylinder chamber 43 in the auxiliary cylinder device 42 via the electromagnetic switching valve 47.

When the cylinder chamber 43 is refueled, a pressing force acts on the auxiliary piston section 44, so that the plunger 22
moves forward, and the power piston 14 moves forward, thereby operating the brake.

This allows the brakes to be maintained automatically without the need to keep pressing the brake pedal, making it possible to park the vehicle on slopes or slopes for long periods of time.

In this case, since an engine-based oil pump is not used, the engine can be stopped or it can be used in a working machine.

Note that the throttle valve 51 is connected to the auxiliary cylinder chamber 43 and the first
Since it is interposed between the chamber 17 and the auxiliary piston section 44, the hydraulic pressure applied to the auxiliary piston section 44 can be increased.
The effective area can be kept small.

When it is desired to release the brake state, when the parking switch 52 is turned OFF, the brake booster switch 53 is turned OFF, so the electromagnetic switching valve 47 is switched, and the electric pump 40 is turned OFF.
stops. Along with this, the plunger 22 is pushed back by the return spring 34, and the pressure oil in the cylinder chamber 43 is discharged into the reservoir tank 3 via the electromagnetic switching valve 47. As a result, the plunger 22 is restored, the power piston 14 is moved back, and the brake is released.

By the way, even if the vehicle is a large vehicle, if it does not carry heavy structures such as working machines, strong auxiliary braking force from a brake booster is not required when parking or stopping on a slope or slope. In such large vehicles, it is sufficient to be equipped with a normal brake booster, so as mentioned above, it is economically disadvantageous to attach an auxiliary cylinder device to the brake booster.

Therefore, in such a case, economic disadvantage can be avoided by replacing the cylinder with an auxiliary cylinder device 42A as shown in FIG. That is, the auxiliary cylinder device 42A shown in FIG.
It is not equipped with a brake booster and only forms part of the cylinder body in a normal brake booster. Therefore, adding the auxiliary cylinder device 42A does not impose any economic burden.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be modified without departing from the gist thereof.
It goes without saying that various changes are possible.

For example, the piston portion of the auxiliary cylinder device is not limited to being formed in a stepped shape on the plunger, but may be formed in a flange shape.

If a sufficient effective area of the auxiliary piston part can be secured in the plunger, the throttle valve in the auxiliary hydraulic circuit may be omitted.

In the embodiment described above, the case where the vehicle is used for parking a large vehicle on a slope or on a slope has been described, but it can also be used in other situations.

[Effect of idea]

As explained above, according to the present invention, it is possible to operate the brake booster without continuously depressing the brake pedal, so that large vehicles such as vehicles equipped with working machinery can be driven safely and easily onto slopes and slopes. It can be easily moved and parked.

Furthermore, since the hydraulic pressure from the electric pump is used as the operating power source for parking and stopping, it becomes possible to use the power of the engine as power for the working machine or to stop the engine.

By configuring the cylinder device in a cartridge type, it can be attached to a desired brake booster as appropriate, so it can be installed only in brake devices for large vehicles that truly require strong auxiliary braking force. Therefore, a vehicle that does not require an auxiliary brake can be equipped with only a normal brake booster, and economic disadvantages can be avoided.

Further, by providing the throttle valve in the cylinder device, the effective area of the piston portion of the cylinder device with respect to the plunger can be suppressed to a small value, so that a decrease in the strength of the plunger can be suppressed.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing a brake device according to an embodiment of the present invention, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is a partially cutaway front view thereof. FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention. FIG. 5 is a hydraulic circuit diagram showing a conventional example. 2... Oil pump unit, 3... Reservoir tank, 8... Brake booster, 9... Brake pedal, 11... Cylinder, 12... Supply path,
13...Discharge passage, 14...Power piston, 15
...Push rod, 16 ... Passage, 17 ... First chamber, 18 ... Second chamber, 19 ... Valve plate, 20 ... Valve port, 21 ... Valve seat, 22 ... Plunger, 23 ... Bearing Member, 24...brake rod, 25...boot, 26...valve part, 27...
Check valve, 28...reaction spring,
31...Sleeve, 33...Snat spring, 3
4... Return spring, 35... End plate, 36... Master cylinder, 37... Piston, 38... Detour, 39... Relief valve, 40
...Electric pump, 41...Flow switch, 42
... Auxiliary cylinder device, 42a ... Auxiliary cylinder body, 42A ... Auxiliary cylinder device, 43 ... Cylinder chamber, 44 ... Auxiliary piston part, 45 ... Oil filler port, 46 ... Auxiliary hydraulic circuit, 47 ... Electromagnetic Switching valve, 48...Pressure switch, 49, 50...Check valve, 51...Throttle valve, 52...Parking switch, 53...Auxiliary cylinder device operation switch, 54...Relay coil, 55...Relay switch .

Claims (1)

[Claims for Utility Model Registration] The brake booster 8 is provided with a brake booster 8 that operates the brake actuator 7, and the brake booster 8 is slidably fitted into the cylinder 11 and is moved forward. A power piston 14 that generates braking force, and a plunger that moves the power piston 14 forward by creating a pressure difference between the fluid supply side and the fluid discharge side of the power piston 14 in the cylinder 11 when the brake pedal 9 is pressed forward. 22 and driven by engine E,
A pump unit 2 supplies fluid to the cylinder 11 during normal times, and a pump unit 2 supplies fluid to the cylinder 11 during abnormal times.
In the brake device, the brake booster 8 includes a cylinder device 42,
42A is provided, and this cylinder device 4
2, 42A is configured to advance the plunger 22 by the output of the electric pump 40 when specified, and is configured in a cartridge type so that it can be attached to any brake booster 8. brake equipment.