JP3601545B2 - Automatic brake device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an automatic brake device, and more particularly, to an automatic brake device using a brake booster.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an automatic brake device using a brake booster, one having the following configuration is known. That is, a valve body slidably provided in the shell, a power piston provided in the valve body, a constant pressure chamber and a variable pressure chamber formed before and after the power piston, and a constant pressure chamber and a valve mechanism formed in the valve body. And a constant-pressure passage that communicates the constant-pressure chamber with the variable-pressure chamber through the valve mechanism and the variable-pressure passage; and a constant-pressure chamber provided in the constant-pressure chamber, with a rear end connected to a front-side end of the constant-pressure passage. A brake booster having a bellows connected to the shell and having a front end connected to a wall surface of the shell, a first conduit provided outside the shell and communicating with an internal space of the bellows; An automatic brake equipped with a control valve capable of selectively introducing a negative pressure or atmosphere into the interior space of the bellows through a first conduit and adjusting the atmospheric pressure introduced into the bellows. · The devices are known (e.g., Japanese Patent Laid-Open No. 4-262957).
In such a conventional automatic brake device, when air is introduced into the internal space of the bellows instead of a negative pressure in a state where the brake pedal is not depressed, the vacuum valve constituting the valve mechanism is opened. Is introduced into the variable pressure chamber through the constant pressure passage, the vacuum valve of the valve mechanism and the variable pressure passage. Thus, the brake booster can be operated without operating the brake pedal, and the function as the automatic brake device can be obtained.
[0003]
[Problems to be solved by the invention]
However, the above-described conventional device has a disadvantage that the automatic brake device cannot be operated while the brake pedal is being operated.
That is, when the brake pedal is operated, the vacuum valve constituting the valve mechanism is closed, and even if air is introduced into the bellows in this state, the constant pressure passage is closed by the vacuum valve, so that the inside of the bellows is closed. Cannot be introduced to the transformer chamber, and the brake booster cannot be operated as an automatic brake device.
By the way, conventionally, there is a case where it is desired to operate the automatic brake device from a state where the brake pedal is operated. For example, when a vehicle equipped with the above-mentioned conventional automatic braking device is running, the inter-vehicle distance to a vehicle traveling ahead is short, and the inter-vehicle distance is desired to be long. In this case, even if the driver operates the brake pedal to brake the vehicle and decelerates, the vehicle may not be decelerated as expected. In such a case, if the automatic braking device can be operated to apply braking to the vehicle, the inter-vehicle distance to the vehicle in front can be lengthened, and the effect is substantially the same as when the brake pedal is increased and depressed Can be obtained.
As described above, in the above-described conventional device, the automatic brake cannot be operated while the brake pedal is being operated. Therefore, there is a demand for an automatic brake device that operates even when the brake pedal is being operated. It was what was.
[0004]
[Means for Solving the Problems]
In view of such circumstances, the present invention provides a valve body slidably provided in a shell, a power piston provided in the valve body, and a negative pressure formed on the front side of the power piston in the shell. A constant-pressure chamber to be introduced, a variable-pressure chamber formed on the rear side of the power piston in the shell, a bellows chamber formed by an internal space of a bellows provided in the constant-pressure chamber, and a brake pedal provided in the valve body. When the brake pedal was not operated , the communication between the variable pressure chamber and the constant pressure chamber was simultaneously performed through the bellows chamber, and at the same time, the communication between the variable pressure chamber and the atmosphere was interrupted, and the brake pedal was operated. negative in a state and a valve mechanism for communicating the same time the variable pressure chamber when shut off communication between the variable pressure chamber and the constant pressure chamber through the bellows chamber to atmosphere A brake booster, and a control valve capable of selectively introducing a negative pressure or atmosphere to the variable pressure chamber via the bellows chamber and the valve mechanism, in a state where the brake pedal is not operated, In the automatic brake device, the atmosphere is introduced from the control valve to the variable pressure chamber via the bellows chamber and the valve mechanism, and the negative pressure type brake booster is operated.
The control valve is adapted to introduce the pressure-adjusted atmosphere from its output side into the bellows chamber, and further comprises a first connection passage directly connecting the variable pressure chamber and the output side of the control valve with the shell. And a first on-off valve is provided in the first connection passage, and when the pressure in the variable pressure chamber is smaller than the pressure of the atmosphere on the output side of the control valve in a state where the brake pedal is operated. The first on-off valve is opened so that the pressure-adjusted atmosphere can be introduced from the control valve into the variable pressure chamber via the first connection passage.
[0005]
[Action]
According to such a configuration, even in the state in which the brake pedal is being operated, by opening the first on-off valve, introducing the atmosphere in which the pressure was adjusted to transformer chamber through the first connecting passage The negative pressure brake booster can be operated as an automatic braking device.
Therefore, for example, when it is desired to increase the inter-vehicle distance while the above-described vehicle is running, when the driver does not brake as much as expected even if the driver depresses the brake pedal to brake the vehicle, The vehicle can be braked by opening the first on-off valve and operating the automatic brake device. As a result, the same effect as when the number of steps is increased can be obtained, and an appropriate inter-vehicle distance can be maintained.
[0006]
【Example】
1 and 2, reference numeral 1 denotes a tandem brake booster, and a shell 2 in which a front plate 4 and a rear room 5 are arranged by a center plate 3 before and after the tandem brake booster. Are divided into two rooms. A cylindrical valve body 6 is slidably penetrated through the opening of the rear wall surface 2A of the shell 2 and the shaft of the center plate 3 via a sealing means while maintaining airtightness.
A front power piston 7 and a rear power piston 8 are connected to the outer periphery of the valve body 6 located in the front chamber 4 and the rear chamber 5, respectively. And the rear diaphragm 12 are respectively stretched. A constant pressure chamber A and a variable pressure chamber B are formed before and after the front diaphragm 11, and a constant pressure chamber C and a variable pressure chamber D are formed before and after the rear diaphragm 12.
A bellows 13 is disposed in the constant-pressure chamber A, and a rear end of the bellows 13 is connected to an outer periphery of a front end of the valve body 6 while maintaining airtightness. The end is connected to the front wall surface 2B of the shell 2 by a support member 9. The bellows 13 divides the inside of the constant-pressure chamber A into a bellows chamber A ′ serving as an internal space of the bellows 13 and a space outside thereof.
The valve body 6 is provided with a valve mechanism 14 for switching the communication between the constant pressure chambers A and C and the variable pressure chambers B and D. The valve mechanism 14 is formed at the right end of an annular first valve seat 15 formed on the valve body 6 and a valve plunger 16 slidably provided on the valve body 6 inside the annular first valve seat 15. An annular second valve seat 17 and a valve element 18 that is seated on both valve seats 15 and 17 by a spring are provided.
A vacuum valve 21 is formed by the first valve seat 15 and an annular seat portion of a valve body 18 which comes into contact with and separates from the first valve seat 15. A space on the outer peripheral side of the vacuum valve 21 is a first constant pressure passage formed in the valve body 6. 22 and the bellows chamber A '.
The bellows chamber A 'is connected via a conduit 23 to a control valve 24 which will be described in detail later, so that a negative pressure or atmosphere can be selectively introduced into the bellows chamber A'. Further, the inside of the constant-pressure chamber A, which is on the outer side of the bellows chamber A ', is always in communication with the negative pressure source via the conduit 25. Therefore, the inside of the constant-pressure chamber A, which is outside the bellows chamber A', Negative pressure is constantly introduced. The inside of the constant-pressure chamber A outside the bellows chamber A 'is always in communication with the constant-pressure chamber C via the second constant-pressure passage 26 provided at a position outside the vicinity of the outer peripheral bead portion 11a of the front diaphragm 11, and therefore, A negative pressure is always introduced into the constant pressure chamber A and the constant pressure chamber C outside the bellows chamber A '.
On the other hand, a space on the inner peripheral side of the vacuum valve 21 and on the outer peripheral side of the atmosphere valve 27 constituted by the second valve seat 17 and the annular seat portion of the valve element 18 which comes in contact with and separated from the second valve seat 17 is formed in the valve body 6. It communicates with a variable pressure chamber D via a first variable pressure passage 31 in the radial direction, and the variable pressure chamber D communicates with a variable pressure chamber B via a second variable pressure passage 32 formed in the valve body 6.
Further, the space on the inner peripheral side of the atmospheric valve 27 is communicated with the atmosphere through an atmospheric passage 33 formed by the inner peripheral surface of the valve body 6 and a filter 34 provided therein.
The right end of the valve plunger 16 is connected to an input shaft 35 linked to a brake pedal (not shown), and the left end of the valve plunger 16 faces a reaction disk 37 housed at the base of the output shaft 36. The left end of the output shaft 36 penetrates through the opening of the wall surface 2B of the shell 2 and is linked to a piston of a master cylinder (not shown).
A return spring 38 is provided between the valve body 6 and the wall surface 2B of the shell 2 so that the valve body 6 can be returned to the non-operating position in the drawing.
Next, as shown in FIG. 1, the control valve 24 of the present embodiment includes a relay valve 41 for introducing a negative pressure or an adjusted atmospheric pressure into the bellows chamber A ′, and a relay valve 41 whose operation is controlled by the control device 39. A pair of solenoid valves 43 and 43 'for moving the piston 42 of 41 forward and backward.
The relay valve 41 includes a piston 42 movably provided in a casing 41A. A first pressure chamber 44 is formed below the piston 42, and a second pressure chamber 45 is formed above the piston 42. Make up. The second pressure chamber 45 communicates with both solenoid valves 43 and 43 ′ via a conduit 46.
A first passage 41a is formed in the casing 41A so as to be continuous from the first pressure chamber 44, and one end of the conduit 23 is connected to the first passage 41a.
A second vertical passage 41b is formed below the first pressure chamber 44 and is continuous with the first pressure chamber 44. A substantially cylindrical valve body 47 is provided in the second passage 41b. A first valve seat 42a is formed at a lower end portion of the piston 42 facing the seat portion of the valve body 47, and a second valve seat 41c is formed at a step portion of the second passage 41b.
The piston 42 is urged upward by a spring 48, and the valve body 47 is also urged upward by a spring 51.
Since the second passage 41b communicates with the constant pressure chamber A outside the bellows chamber A 'through the conduit 52 connected to the second passage 41b, a negative pressure is always introduced to the inside of the valve body 47. ing.
In the non-operating state of the relay valve 41 shown in FIG. 1, the valve body 47 is seated on the second valve seat 41c and is separated from the first valve seat 42a. A pressure is introduced, and thus a negative pressure is also introduced via the conduit 23 into the bellows chamber A ′.
The casing 41A has a third passage 41d communicating with a second passage 41b on the outer side of the valve body 47. The third passage 41d has a predetermined passage through a vacuum regulator 53 described later. Atmosphere reduced to pressure is introduced.
In the non-operating state of the tandem brake booster 1 having the above configuration, the control device 39 closes the left electromagnetic valve 43 and opens the right electromagnetic valve 43 ′. Therefore, since the negative pressure is introduced into the second pressure chamber 45 of the relay valve 41 via the electromagnetic valve 43 ′ on the right side and the conduit 46, the piston 42 urged by the spring 48 is moved to the non-operating position in the drawing. Has stopped.
In this non-operating state, the first valve seat 42a is separated from the valve body 47 and the valve body 47 is seated on the second valve seat 41c. Negative pressure is introduced. That is, the negative pressure is introduced into the entire constant pressure chamber A including the bellows chamber A '.
When the tandem brake booster 1 is not operated, the atmospheric valve 27 is closed and the vacuum valve 21 is open. Therefore, the negative pressure introduced into the bellows chamber A ′ is the first constant pressure. In addition to the passage 22 and the vacuum valve 21, the gas is introduced into each of the transformation chambers B and D via both transformation passages 31 and 32.
When the brake pedal (not shown) is depressed from this state, the input shaft 35 is advanced, so that the vacuum valve 21 is closed, while the atmospheric valve 27 is opened, and the air valve 27 is opened via the atmospheric valve 27 and both the variable pressure passages 31 and 32. Atmosphere is introduced into the transformation chambers B and D. Therefore, the power pistons 427 and 8 and the entire valve body 6 are moved forward by the differential pressure generated between the constant pressure chambers A and C and the variable pressure chambers B and D, so that the tandem brake booster 1 is used as conventionally known. Boosting action can be obtained.
The tandem brake booster 1 can function as an automatic brake device with respect to the operation of the normal tandem brake booster 1 described above. That is, when the tandem brake booster 1 in which the brake pedal is not depressed is given a command to the control device 39 to function as an automatic brake device, the control device 39 causes the pair of solenoid valves to operate. 43 and 43 ′ are alternately opened and closed to introduce the air adjusted to a required pressure into the second pressure chamber 45 via the conduit 46.
As a result, the piston 42 of the relay valve 41 is pushed down against the spring 48, so that the first valve seat 42a is seated on the valve body 47, while the valve body 47 is separated from the second valve seat 41c. As a result, the atmosphere is introduced into the bellows chamber A 'instead of the negative pressure. Note that the air introduced into the bellows chamber A ′ has a pressure corresponding to the adjusted air introduced into the second pressure chamber 52.
As described above, since the vacuum valve 21 is open when the tandem brake booster 1 is not in operation, the atmosphere introduced into the bellows chamber A 'thereafter flows into the first constant pressure passage 22, the vacuum valve 21 and Atmosphere is introduced into the two transformation chambers B and D via the two transformation paths 31 and 32. Therefore, both the power pistons 7, 8 and the valve body 6 are advanced, and the tandem brake booster 1 can be operated without depressing the brake pedal, so that a function as an automatic brake device can be obtained.
Since the air introduced into the bellows chamber A 'also acts on the first pressure chamber 44 of the relay valve 41, the piston 42 is urged upward by the air introduced into the first pressure chamber 44. . Therefore, the atmospheric pressure in the first pressure chamber 44 for urging the piston 42 upward and the urging force of the spring 48 balance the atmospheric pressure in the second pressure chamber 45 pushing the piston 42 downward. Then, at that time, both the valve seats 41c and 42a are simultaneously seated on the valve body 47, and at this time, the atmosphere in the bellows chamber A 'stops.
However, in the configuration described above, the tandem brake booster 1 cannot be operated as an automatic brake device while the brake pedal is being operated. In other words, when the brake pedal is operated, even if air is introduced into the bellows chamber A ′ to make the tandem brake booster 1 function as an automatic brake device, the bellows is closed because the vacuum valve 21 is closed. This is because the atmosphere in the chamber A ′ cannot be introduced into the transformation chambers B and D.
Therefore, in the present embodiment, on the premise of the above-described configuration, the tandem brake booster 1 is improved so that it can function as an automatic brake device even when the brake pedal is operated. .
That is, in the present embodiment, one end 54a of the conduit 54 is connected to the middle of the conduit 23, and one end 54a of the conduit 54 is connected to the first passage 41a of the relay valve 41 via the conduit 23 on the upstream side of the connection part. On the other hand, the other end 54b of the conduit 54 is connected to the position of the opening of the wall surface 2A of the shell 2 and communicates with the transformation chamber D. An electromagnetic valve 55 which is opened and closed by the control device 39 is provided in the conduit 54. Instead of connecting the one end 54a of the conduit 54 to the middle of the conduit 23, the one end 54a may be directly connected to the first passage 41a of the relay valve 41, or may be directly connected to the bellows chamber A '.
Further, a first differential pressure sensor 56 as pressure detecting means is provided between the conduit 54 and the conduit 25. The first differential pressure sensor 56 compares the pressure in the constant pressure chamber A outside the bellows chamber A ′ with the pressure in the variable pressure chamber D, and inputs the result to the control device 39. Has become. Further, a second differential pressure sensor 57 is provided as a pressure detecting means even when it passes through the conduit 52 and the conduit 23, and the pressure in the bellows chamber A 'and the pressure in the constant pressure chamber A on the outside of the bellows chamber A' are provided. Are compared, and the result is input to the control device 39.
Further, in this embodiment, the pressure of the atmosphere introduced into the third passage 41d of the relay valve 41 is reduced to a predetermined pressure by the regulator 53.
That is, the third passage 41d of the relay valve 41 is opened to the atmosphere via the conduit 61, and a vacuum regulator 53 having a conventionally known configuration is disposed in the conduit 61. The vacuum regulator 53 can introduce a negative pressure from a negative pressure source, and the vacuum regulator 53 lowers the atmosphere introduced into the third passage 41d to a predetermined pressure.
A conduit 61 on the upstream and downstream sides of the vacuum regulator 53 is communicated with another conduit 62, and an electromagnetic valve 63 controlled to be opened and closed by the control device 39 is provided in the conduit 62.
In the above configuration, the control device 39 controls the operation of the solenoid valves 55 and 63 as follows based on the input results from the two differential pressure sensors 56 and 57.
That is, the control device 39 normally closes the solenoid valves 55 and 63 as shown in FIG. Therefore, the variable pressure chamber D and the bellows chamber A ′ do not communicate with each other, and the atmosphere reduced to a predetermined pressure by the vacuum regulator 53 is introduced into the third passage 41 d of the relay valve 41.
As described above, when the tandem brake booster 1 in which the brake pedal is not depressed is given a command to the control device 39 to function as an automatic brake device, the control device 39 The air after being adjusted to a required pressure is introduced into the second pressure chamber 45 via the conduit 46 by alternately opening and closing the pair of solenoid valves 43 and 43 ′. As a result, the atmosphere reduced in pressure by the vacuum regulator 53 is introduced into the bellows chamber A 'instead of the negative pressure, so that the tandem brake booster 1 can be operated without depressing the brake pedal.
As described above, in the present embodiment, when the tandem brake booster 1 functions as an automatic brake device from a state where the brake pedal is not depressed, the atmosphere introduced into the bellows chamber A ′ is reduced to a predetermined pressure by the vacuum regulator 53. It has been lowered to Therefore, if the brake pedal is not depressed, the relay valve 41 or the solenoid valve 43 (43 ') breaks down, the piston 42 of the relay valve 41 is pushed down, and the air in the third passage 41d is released from the bellows chamber. When introduced to A ', the tandem brake booster 1 is operated as an automatic brake regardless of the driver's intention. However, in this case, since the atmosphere introduced into the bellows chamber A 'and the transformation chambers A and D is reduced to a predetermined pressure by the vacuum regulator 53, the deceleration is so gentle that the driver does not feel uneasy. The vehicle will be braked. In other words, even if the tandem brake booster 1 operates at the time of the above-described failure, it is possible to obtain a deceleration that does not cause anxiety to the driver. On the other hand, in the case of the above-described failure, if the air that has not been reduced by the vacuum regulator 53 is directly introduced into the bellows chamber A ′ and the transformation chambers A and D, the deceleration will be abrupt and the driver will be uneasy. The drawback is that you will have a problem.
Next, a case where the brake pedal is operated (the vacuum valve 21 is closed) and the tandem brake booster 1 functions as an automatic brake device will be described. In this case, a certain degree of air has already been introduced into both the transformation chambers A and D.
In this case, when a command to make the tandem brake booster 1 further function as an automatic brake device is given to the control device 39, the control device 39 controls the solenoid valves 43 and 43 'to lower the piston 42 of the relay valve 41. Then, air is introduced into the bellows chamber A '.
When the pressure in the variable pressure chamber D is smaller than the pressure in the bellows chamber A ′ due to the input from the two differential pressure sensors 56 and 57 to the control device 39, the control device opens the solenoid valve 55, 63 is also released.
As a result, the atmosphere in the bellows chamber A 'is directly introduced into the transformer chamber D via the conduit 54, so that the tandem brake booster 1 is provided despite the fact that the vacuum valve 21 of the valve mechanism 14 is closed. Can further function as an automatic brake device to apply braking to the vehicle. At this time, since the air that has not been reduced by the vacuum regulator 53 is introduced into the third passage 41 d of the relay valve 41 due to the opening of the electromagnetic valve 63, the air is introduced into the transformation chamber D through the conduit 54. The flow rate of the introduced atmosphere is increased. Therefore, in this case, a large deceleration can be obtained when braking the vehicle.
Then, after opening the electromagnetic valve 55, the control device 39 changes the atmospheric pressure in the variable pressure chamber D to the atmospheric pressure in the bellows chamber A 'based on the input results from the two differential pressure sensors 56 and 57. When it is found that the values have become the same, both the electromagnetic valves 55 and 63 are closed.
According to the present embodiment, for example, when the vehicle equipped with the brake device of the present embodiment is running, the inter-vehicle distance to a vehicle traveling ahead is short, and the inter-vehicle distance is desired to be long. It is suitable for cases and the like. In other words, when the inter-vehicle distance between the vehicle and the vehicle traveling in front is short, the driver depresses the brake pedal to apply a brake to his own vehicle and decelerates, but at that time, the driver does not decelerate as expected. Sometimes. At this time, since the brake pedal is depressed, the vacuum valve 21 is closed, and from this state, the piston 42 of the relay valve 41 is pushed down to operate the automatic braking device, and the atmosphere is introduced into the bellows chamber A '. Even if it is introduced, the air is blocked by the vacuum valve 21 so that the air in the bellows chamber A 'is not introduced into the variable pressure chamber as it is.
However, at this time, as described above, the control device 39 opens the solenoid valves 55 and 63 based on the detection results of the two differential pressure sensors 56 and 57. Therefore, since the atmosphere in the bellows chamber A 'is introduced into the transformer chamber D, the output of the tandem brake booster 1 can be increased by causing the tandem brake booster 1 to function as an automatic brake device. Therefore, the vehicle is braked by the amount of the output increase, so that the same effect as when the brake pedal is increased and depressed can be obtained, whereby the appropriate inter-vehicle distance can be maintained.
According to the present embodiment, the tandem brake booster 1 can be operated as an automatic brake device even while the brake pedal is being operated.
In the above embodiment, the pressures in the variable pressure chamber D and the bellows chamber A 'are compared based on the input results from the two differential pressure sensors 56 and 57. However, the variable pressure chamber D and the bellows chamber A' are compared. May be provided with pressure detecting means, respectively, and input to the control device 39.
The present invention can be applied to a single type booster including a pair of constant pressure chambers and a variable pressure chamber in the shell 2 instead of the tandem brake booster 1 in the above embodiment.
[0007]
【The invention's effect】
As described above, according to the present invention, an effect is obtained that the automatic brake device can be operated even from the state where the brake pedal is operated.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is an enlarged sectional view of a main part in FIG.
Reference Signs List 1 tandem brake booster 7 front power piston 8 rear power piston 13 bellows 23 conduit (first conduit) 24 control valve 39 control device 41 relay valve 42 piston 43, 43 'solenoid valve 44 first pressure chamber 45 second pressure chamber 42a first valve seat 41c second valve seat 47 valve body 48 spring (first spring)
51 spring (second spring) 53 vacuum regulator 54 conduit (second conduit) 55 solenoid valve (open / close valve)
56 first differential pressure sensor 57 second differential pressure sensor 63 solenoid valve

Claims (5)

A valve body slidably provided in the shell, a power piston provided in the valve body, a constant-pressure chamber formed on the front side of the power piston in the shell to introduce a negative pressure; A variable pressure chamber formed on the rear side of the power piston, a bellows chamber formed by the internal space of the bellows provided in the constant pressure chamber, and a brake pedal provided in the valve body and operated in conjunction with the brake pedal. In the absence state, the variable pressure chamber and the constant pressure chamber are communicated with each other through the bellows chamber, and at the same time, the communication between the variable pressure chamber and the atmosphere is cut off.When the brake pedal is operated, the pressure is reduced through the bellows chamber. A negative pressure type brake booster having a valve mechanism for interrupting communication between the pressure chamber and the constant pressure chamber while simultaneously communicating the variable pressure chamber with the atmosphere; A control valve capable of selectively introducing negative pressure or atmosphere through the bellows chamber and the valve mechanism.When the brake pedal is not operated, the bellows chamber and the valve mechanism are moved from the control valve. In the automatic brake device, which introduces the atmosphere into the transformation chamber via the negative pressure type brake booster,
The control valve is adapted to introduce the pressure-adjusted atmosphere from its output side into the bellows chamber, and further comprises a first connection passage directly connecting the variable pressure chamber and the output side of the control valve with the shell. And a first on-off valve is provided in the first connection passage, and when the pressure in the variable pressure chamber is smaller than the pressure of the atmosphere on the output side of the control valve in a state where the brake pedal is operated. An automatic brake device, wherein the first on-off valve is opened so that the pressure-adjusted atmosphere can be introduced from the control valve into the variable pressure chamber via the first connection passage. Pressure control means for reducing the atmosphere connected to the input side of the control valve to a predetermined pressure is provided, and an air passage for directly introducing the air to the input side of the control valve is provided. The automatic brake device according to claim 1, wherein the automatic brake device is provided. The control valve has a relay valve unit for introducing atmospheric pressure or negative pressure with adjusted pressure into the bellows chamber, and an electromagnetic valve for supplying a control pressure for controlling the operation of the relay valve unit to the relay valve unit. The automatic brake device according to claim 1 or 2, wherein The relay valve portion includes a piston slidably provided in the housing, a first pressure chamber provided on one side of the piston and connected to an output side of the control valve, and another side of the piston. A second pressure chamber connected to the solenoid valve and a communication state between the second pressure chamber and the first pressure chamber in conjunction with advance and retreat of the piston. 4. The method according to claim 3, further comprising: a switching valve for introducing a negative pressure or a pressure-adjusted atmosphere on the input side to the first pressure chamber when the first pressure chamber is communicated with the first pressure chamber. Automatic brake device as described. When the pressure on the output side of the control valve is lower than the pressure in the variable pressure chamber, the first on-off valve is closed. When the pressure on the output side is higher than the pressure in the variable pressure chamber, the first on-off valve is closed. The automatic brake device according to any one of claims 1 to 4, wherein the brake is released.

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