JPS6240220B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake control valve used in an air brake system for a tractor and trailer combination vehicle, and particularly for a combination vehicle equipped with a spring brake chamber operated by a dual brake valve. The present invention relates to a brake control valve used for operating a spring brake part of a spring brake chamber in an air brake system for use in a commercial air brake system.

Conventionally, air brake systems for tractors and trailers are equipped with a spring brake chamber operated by a dual brake valve, and the spring brake part of the spring brake chamber is operated by a hand control valve. BACKGROUND OF THE INVENTION Brake systems for tractors and trailer-coupled vehicles are known which have a side brake system part and a trailer side brake system part connected to the tractor side brake system part via a service line and an emergency line. In this system, there is a slight pressure difference between the two outlet ports of the dual brake valve, the high pressure side outlet port is connected to the spring brake chamber for the rear wheels, and the low pressure side outlet port is connected to the spring brake chamber for the front wheels. The brake chamber is connected. Further, in the trailer-side brake system portion, the service line and the emergency line are connected to the brake chamber for the trailer wheels via a relay emergency valve.

In the conventional air brake system mentioned above, when the dual brake valve is stepped on while driving, pressure air is sent to the brake chamber and spring brake chamber at a pressure proportional to the amount of depression, applying brakes to the front and rear wheels of the tractor. . In addition, the high-pressure side outlet port pressure of the dual brake valve is transmitted to the relay emergency valve via the service line, and pressurized air at a pressure proportional to the amount of depression is also sent to the trailer wheel brake chamber. The brakes are applied in a similar way to the rear wheels of a tractor.

In addition, when the hand control valve is operated in the event of a service brake failure, parking or stopping, or starting on a slope, the pressure air compressing the spring in the spring brake part of the spring brake chamber is released by an amount proportional to the rotation angle of the operating handle. The air is exhausted, the pressure is reduced, and the force of the spring applies the brakes to the rear wheels of the tractor. When the vehicle is parked or stopped, the operating handle of the hand control valve is rotated as far as possible, and the pressurized air in the spring brake section is completely exhausted. When the operating lever is returned to its original position, the spring brake section is again supplied with pressurized air, the spring is compressed again, and the brake is released.

Furthermore, if the emergency line is damaged and reaches atmospheric pressure due to damage to the connection between the tractor and trailer, pressurized air is sent to the brake chamber for the trailer wheels by the action of the relay emergency valve, and the pressure air is sent to the trailer wheels. The system automatically applies the emergency brake to prevent unexpected accidents.

In the above air brake system for a coupled vehicle, the high pressure side outlet port of the dual brake valve and the service line are connected via a special trailer control relay valve, and the hand control valve is connected via a special trailer control relay valve. The outlet port of the relay valve is also connected to the service line, and when the dual brake valve is operated, a pressure approximately equal to the high pressure side outlet port pressure is generated in the relay valve, and that pressure is transmitted to the relay emergency valve via the service line. In addition to applying the brakes to the trailer, when the hand control valve is operated, the above relay valve generates air pressure that increases in proportion to the amount of pressure reduction, and that pressure is sent to the relay emergency valve via the service line. A system has been proposed in which a brake similar to that applied to the rear wheels of a tractor is applied to the trailer wheels.

The trailer control relay valve proposed above is disclosed in a patent application entitled "Trailer Control Relay Valve" (Japanese Unexamined Patent Publication No. 12859/1983) filed by the applicant on the same date as the present application.

In the preferred embodiment of the trailer control relay valve disclosed in this same application, the low pressure side outlet port of the dual brake valve is also connected to the service line via the relay valve, and normally the dual brake valve is connected to the service line via the relay valve. The high-pressure side outlet port of It operates in response to the pressure at the outlet port and transmits approximately the same pressure to the service line for added safety.

Furthermore, in the above preferred embodiment, the air tank and the emergency line are also connected through the relay valve, so that if only the service line is damaged for some reason and the pressure no longer increases, In response to the operation of the brake valve, the emergency line is evacuated to atmospheric pressure, the relay emergency valve is operated, and the emergency brake is applied to the trailer wheels. The structure of the relay valve for trailer control that focuses on this function is disclosed in the "Relay Valve for Trailer Control" filed by the applicant on May 29, 1981.
It is disclosed in Japanese Patent Application No. 56-80931 (Japanese Patent Publication No. 62-4265) entitled.

However, in the air brake system for articulated vehicles that incorporates the trailer control relay valve described above, when the hand control valve is operated as described above, the brake is applied not only to the rear wheels of the tractor but also to the trailer wheels in proportion to the amount of rotation of the operating handle. Therefore, even when the operating handle is turned all the way to the fully operating position for parking or stopping, the brakes are naturally applied to the rear wheels of the tractor and the trailer wheels, but when parking or stopping, the brakes are not necessarily applied to the trailer wheels as well. It turns out that it is not always safe to suffer from this.

For example, when a coupled vehicle is parked on a slope, if you pull the operating handle of the hand control valve all the way as described above to apply the brakes to the rear wheels of the tractor and the trailer wheels, the rear wheels of the tractor will be braked by the spring brake part of the spring brake chamber. Since the brakes are applied by the force of the spring by discharging the pressurized air, there is no need to worry even if the air pressure drops due to a malfunction in the piping, etc. However, the trailer wheels do not need to worry about the brakes being applied by the force of the spring by discharging the pressurized air. Since the brake is applied, there is a possibility that the brake will be released if the air pressure decreases due to a failure in the piping or the like. Therefore, when the vehicle is initially parked, it is stopped on a slope by the braking force of both the rear wheels of the tractor and the trailer vehicle, but after the driver leaves the coupled vehicle, the air pressure decreases and the braking force of the trailer wheels decreases. If the brake is released, if the slope is steep, the braking force of the rear wheels of the tractor alone will not be enough to brake the entire connected vehicle, which could lead to a serious accident.

On the other hand, if you apply the brakes only to the rear wheels of the tractor when parking or stopping, you will know in advance if the slope is steep and the brakes on the rear wheels of the tractor alone will not be able to brake the entire connected vehicle. Accidents can be prevented by taking appropriate safety measures such as changing the parking position.

From the above-mentioned safety standpoint, some European countries require the adoption of a mechanism that prevents the trailer wheels from applying brakes when the vehicle is parked or parked.

An object of the present invention is to use the above-mentioned air brake system for tractors and trailer-coupled vehicles in place of the conventional hand control valve, and to use the air brake system in proportion to the amount of rotation of the operating handle until the operating handle is fully rotated to the fully operating position. The spring brake part of the spring brake chamber for the rear wheels of the tractor is depressurized and the pressure of the brake chamber for the trailer wheels is increased. When the operation handle is fully rotated to the fully operating position, the spring brake part is completely exhausted and the trailer wheel is completely evacuated. To provide a brake control valve which completely exhausts a wheel brake chamber and prevents the trailer wheels from being braked when parked or stopped.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a tractor-side brake device portion of an air brake system for a tractor and trailer coupled vehicle in which the brake control valve of the present invention is incorporated, and in the figure, the brake control valve of the present invention is designated by the reference numeral 2.

This tractor-side brake system portion has a dual brake valve 8 connected to air tanks 4 and 6, and a slight pressure difference exists between the pressures of its two outlet ports 10 and 12 of the dual brake valve 8. dual brake valve 8
The high-pressure side outlet port 10 of is connected to a rear wheel spring brake chamber 16 via a relay valve 14. A low pressure side outlet port 12 of the dual brake valve 8 is connected to a front wheel brake chamber (not shown). The brake control valve 2 of the present invention has an inlet port 18, a first outlet port 20, and a second outlet port 22, as described below. The inlet port 18 is connected to an air tank 24, and the first outlet port 20 is connected to an air tank 24. It is connected to a spring brake section 28 of the spring brake chamber 16 via a double check valve 26.

The two outlet ports 10 and 12 of the dual brake valve 8 are connected to the service line 3 via the special trailer control relay valve 30 mentioned above.
2, and the second outlet port 22 of the brake control valve 2 is also connected to a service line 32 via a trailer control relay valve 30, and an air tank 34 is connected to the emergency line via this relay valve 30. 36.

Although not shown, a relay emergency valve of the trailer side brake system is connected to the service line 32 and the emergency line 36, and the brake chamber for the trailer wheels is connected to the brake chamber for the trailer wheels via this relay emergency valve. Air is now being sent.

The details of the trailer control relay valve 30 are disclosed in the patent application titled "Trailer Control Relay Valve" filed on the same day as the present application, as mentioned above, but in order to facilitate understanding of the brake control valve of the present invention, the details are simplified. Specifically, when the dual brake valve 8 is operated, the trailer control relay valve 30 operates in response to the higher pressure air from either of the two outlet ports 10 and 12, and is approximately equal to that pressure. Pressure is generated based on air from an air tank 34, and the pressure is transmitted to a relay emergency valve via a service line 32. Therefore, normally, a pressure approximately equal to the pressure at the high-pressure side forward outlet port 10 is transmitted to the relay emergency valve, and the pressure of the air sent to the spring brake chamber 16 and the pressure of the air sent to the trailer wheel air chamber are normally transmitted to the relay emergency valve. are approximately equal, and approximately equal braking force is applied to the rear wheels of the tractor and the wheels of the trailer. In the event of a failure in the rear wheel brake system to which the high-pressure side outlet port 10 is associated, a pressure approximately equal to the pressure at the low-pressure side outlet port 12 is sent to the service line 32, which also applies the brakes to the trailer wheels. be able to.

Furthermore, in the past, an ordinary hand control valve has been used instead of the brake control valve 2 of the present invention, and in this case, one outlet port of the hand control valve is connected to the spring brake section 2 of the spring brake chamber 16.
8 and is also connected to a trailer control relay valve 30. When the hand control valve is not operated, high pressure air from the air tank is directly sent to its outlet port, and when such high pressure air is acting on the trailer control relay valve 30, the service line 32 is maintained at atmospheric pressure. be done. When the operation handle of the hand control valve is operated, the pressure at the outlet port is reduced in proportion to the amount of operation, and in the spring brake chamber 16, the pressure air compressing the spring in the spring brake section 28 is reduced.
The brake is applied to the rear wheels of the tractor by the force of the spring, but the trailer control relay valve 30
In the system, an increased pressure proportional to the amount of pressure reduction is generated based on the pressure air from the air tank, and this pressure is transmitted to the relay emergency valve via the service line. Therefore, when the hand control valve is operated, air with a pressure approximately equal to the amount of pressure reduction in the spring brake section is sent to the trailer wheel brake chamber, and a braking force approximately equal to the braking force on the rear wheels of the tractor is also applied to the trailer wheels. be able to.

Next, the structure of the brake control valve 2 of the present invention will be explained with reference to FIGS. 2 to 4. The brake control valve 2 has an inlet port 18 and a first outlet port 20, and a a first valve arrangement portion 42 having an exhaust port 38 and an operating handle 40 variably operable between an inoperative position and a fully operative position; 1 passage 44 and a second passage 46 communicating with inlet port 18, and a second valve arrangement portion 48 having second outlet port 22 previously described.

The first valve assembly portion 42 has substantially the same construction as a conventional hand control valve, and communicates the first outlet port 20 with the inlet port 18 when the operating handle 40 is in the non-operating position. The first outlet port 20 communicates with the exhaust port 38 when in the fully operative position and when the operating handle 40 is in an intermediate operative position between the non-operative and fully operative positions.
is configured to communicate with the inlet port 18 and the exhaust port 38 in a controlled manner to reduce the pressure in the first outlet port 20 in proportion to the amount of operation of the operating handle 40.

That is, in brief, the base 50 of the operating handle 40
is rotatably mounted on a housing 52 in a sealed manner, and a shaft 54 extending into the housing 52 is integrally provided at the center of the base 50, and a pin 56 is fixedly fixed to the shaft 54 through the shaft 54 in a radial direction. . An operating piston 58 is housed in the housing 52 so as to be able to reciprocate in a sealed manner, and a face cam 60 is placed on the operating piston 58 to face the pin 56 . At a position corresponding to the non-operating position of the operating handle 40, the pin 56 engages with a higher cam surface of the face cam 60, and the operating piston 58 is moved by the spring 62.
is pushed down to its initial position against the force of
When the operating handle 40 is rotated, the operating piston 58
is pushed upward by the force of the spring 62 along the cam surface of the face cam 60, and the operation handle 4
In the position corresponding to the fully operated position of 0, the pin 56 engages the lower cam surface of the face cam 60 and the operating piston 58 is raised to its full height position as shown in FIG. The face cam is configured to be able to reciprocate on the axis together with the operating piston 58, but not rotate. The lower end of the operating piston 58 is a valve seat 64, which can engage with a valve surface 68 of a valve body 66, which will be described later, and together constitute a first seat valve.

A control piston 70 is also housed within the valve housing 52 so as to be able to reciprocate in a sealed manner, and a valve body 66 is supported in a central portion of the control piston 70 so as to be slidable in a sealed manner. A central hole 76 is formed in the valve body 66 passing through the valve stem portion 72, and the central hole 76 connects the first outlet port 20 to the exhaust port 38 when the first seat valves 64, 68 are open. It is designed to communicate. Also, the control piston 70
Another valve seat 78 is provided on the inner peripheral portion of the valve body 66 to face the valve surface 68 of the valve body 66 and surround the valve seat 64, and the valve seat 78 and the valve surface 68 constitute a second seat valve. . The control piston 70 is provided with a communication hole 80 as shown, and the second seat valve 68,
When 78 is open, it communicates the first outlet port 20 with the inlet port 18. Note that 82 and 84 are springs that press and hold the control piston 70 and the valve body 66 upward, respectively.

When the operating handle 40 is in the non-operating position,
The operating piston 58 has been pushed down to its initial position as described above, and the first seated valves 64, 6
8 is closed, the second seat valve 68, 78 is opened, the first outlet port 20 communicates with the inlet port 18, and the pressure P ₁ of the first outlet port 20 is maintained at the pressure of the air tank. . Operation handle 40
When the piston 58 is rotated to its fully operative position, the piston 58 is pushed up to its highest position, as described above, and the first seated valve 64,6 is rotated as shown in FIG.
8 is opened and the second seated valves 68, 78 are closed, placing the first outlet port 20 in communication with the exhaust port 38, so that the pressure P ₁ at the first outlet port 20 is at atmospheric pressure. When the operating handle 40 is in an intermediate operating position between the non-operating position and the fully operating position, the operating piston 58 is pushed up by a distance proportional to the amount of rotation thereof by the action of the face cam 60, and the first seat valve is instantaneously pushed up. 64, 68 and close the second seat valve 68, 78, but the first outlet port 2
When the pressure at 0 decreases, the control piston 70 also rises,
Close the first seat valves 64, 68 again. Therefore, the pressure P ₁ at the first outlet port 20 is reduced in proportion to the amount of operation of the operating handle 40 .

A spring 86 is built into the base 50 of the operating handle 40, and the inner tip 8 of the operating handle 40
8 is pressed against the housing 52, and the housing 52 is formed with a recess 90, as shown in FIG. 90 and is locked at that position.

Next, describing the structure of the second valve device 48, the housing 92 of the second valve device portion 48
is formed integrally with the housing 52 of the first valve device part 42, so that the first passage 44 and the second passage 46 are formed as holes in the partition 94 forming part of the housing 52, 92. . Second
The valve system portion 48 is broadly divided into a first position that communicates the second outlet port 22 with the first passageway 44 and a first position that communicates the second outlet port 22 with the first passageway 46 .
an operating device 98 for operating a valve mechanism 96 movable between a second position in communication with the valve mechanism 96;

The operating device 98 has an actuating member 100 integral with the operating handle 40, which in the illustrated embodiment is a projection projecting from the base 50 of the operating handle. The operating device 98 also has a plunger 106 consisting of a small diameter portion 102 and a large diameter portion 104, the large diameter portion 104 is located within the housing 92, and the small diameter portion 102 is supported by the housing 92 in a sealed and slidable manner. , a tip 108 of the small diameter portion 102 projects outward beyond the housing 92. When the pressure around the large diameter portion 104 is equal to or higher than atmospheric pressure, the plunger 106 is always held in the raised position shown in FIG. 2 due to the pressure difference. The protrusion 100 of the operating handle base 50 engages the tip 10 of the plunger 106 when the operating handle 40 is moved to the fully operated position.
The protrusion 100 is provided at an angular position such that it is above the plunger 1 when the operating handle 40 is moved to the fully operating position.
A cam surface 110 is formed that engages the tip 108 of the 06 and pushes it down. The valve mechanism 96 has a valve stem portion 114 on the opposite side of the valve face 112.
The valve body 116 is slidably supported by the housing 92 at the valve stem portion 114 via a support stand 118 in a sealed manner. Valve face 112 is preferably made of a resilient material.
The valve body 116 is also formed with a central hole 120 that can pass through the valve stem portion 114 and allow the first passage 44 to communicate with the second outlet 22 . The plunger 106 described above is movable coaxially with the valve body 116, and the large diameter portion 10 of the plunger 106
A valve seat 122 is provided at the tip of 4 so as to face the valve surface 112, and the valve surface 112 and the valve seat 12
2 constitutes a first seat valve that opens and closes the central hole 120. As previously mentioned, the plunger 106 is normally in the raised position, so the first seated valve 112, 122 is open and the second outlet port 2 is opened.
2 communicates with the first passage 44. The housing 92 also includes a large diameter portion 104 of the plunger 106.
Another valve seat 124 is integrally provided surrounding the outside of the valve and facing the valve surface 112 , and the valve surface 112 and the valve seat 124 open and close the communication passage 126 between the second passage 46 and the second outlet port 22 . It constitutes a second seat valve. The valve body 116 is constantly pressed upward by the spring 128, and the second
The seat valves 112 and 124 of the second outlet port 122 and the second passage 46 are closed to block communication between the second outlet port 122 and the second passage 46.

Regarding the operation of the second valve device portion 48, when the operating handle 40 is in the non-operating position and the intermediate operating position, the cam surface 110 of the protrusion 100 does not engage the small-diameter tip 108 of the plunger 106, so that the As shown in FIG. 2, plunger 106 is maintained in its raised position, first seated valves 112, 122 remain open and second outlet port 22 communicates with first passageway 44.
Therefore, the pressure P ₂ at the second outlet port 22 is equal to the first
has the same value as the pressure P ₁ at the first outlet port 20 of the valve device part 42 of . That is, when the operating handle 40 is in the non-operating position, the second outlet port 22
The pressure _P2 is maintained at the high pressure in the air tank, and when the operating handle 40 is in the intermediate operating position, the second
The pressure at the outlet port 22 of the pump decreases in proportion to the manipulated variable.

When the operating handle 40 is moved to the fully operated position, the cam surface 110 of the protrusion 100 engages and depresses the small diameter tip 108 of the plunger 106, causing the first seated valve 112, as shown in FIG.
122 and at the same time the second seat valve 112,
Open 124. Therefore the second outlet port 2
2 is communicated with the first passage 46, and the pressure P ₂ at the second outlet port 22 suddenly rises again to the high pressure of the air tank. At this time, as mentioned above, the first
The pressure P ₁ at the first outlet port 20 of the valve device section 42 is at atmospheric pressure.

The relationship between these pressures P ₁ and P ₂ is shown in a graph as shown in FIG.

As mentioned above, brake control valve 2
A first outlet port 20 of the spring brake chamber 16 is connected to a spring brake portion 28 of the spring brake chamber 16, and a second outlet port 22 is connected to a trailer control relay valve 30. Therefore, the operating handle 40 of the brake control valve 2
When the operation handle 40 is in the intermediate operation position, the reduced pressure is transmitted to the trailer control relay valve 30 in proportion to the amount of operation, and as described above, the trailer control relay valve 30 absorbs the pressure. In response to the decrease in , an increased pressure proportional to the decrease is generated based on the pressure air from the air tank 34, and the pressure is transmitted to the relay emergency valve via the service line 32,
Air of similar pressure is sent to the trailer wheel brake chamber. Therefore, a braking force approximately equal to the braking force applied to the rear wheels of the tractor by the spring brake portion 28 is also applied to the tractor wheels.

Furthermore, when the operating handle 40 of the brake control valve 2 is moved to the fully operating position to park or stop the coupled vehicle, the pressurized air in the spring brake section 28 connected to the first outlet port 20 is completely exhausted, and the rear wheel of the tractor is The parking brake is applied, but the high pressure of the air tank 24 acts again on the trailer control relay valve 30 connected to the second outlet port 2'2, so the relay valve 3
0 connects service line 32 back to the atmosphere;
The pressure air acting on the relay emergency valve is exhausted, the pressure air in the trailer wheel brake chamber is exhausted, and the brakes applied to the trailer wheels are released.

The brake control valve of the invention thus provides, in addition to a first valve device part of similar construction to a conventional hand control valve having an inlet port 18 and a first outlet port 20, a non-operating part of the operating handle. A second valve device part is provided having a second outlet port 22 which communicates with the first outlet port 20 in the position and the intermediate operating position and which communicates with the inlet port 18 in the fully operating position of the operating handle 40. When the operating handle 2 is moved to the fully operating position and the vehicle is parked or parked, the brakes are not applied to the trailer wheels but only to the rear wheels of the tractor.
If the slope is steep and the brakes on the rear wheels of the tractor alone cannot brake the entire connected vehicle, this can be known in advance and accidents can be prevented by taking appropriate safety measures such as changing the parking position. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a tractor-side brake device part of an air brake system for tractors and trailer-coupled vehicles incorporating one embodiment of the brake control valve of the present invention, and FIG.
FIG. 3 is a sectional view of the brake control valve shown in the figure, showing the state when the operating handle 40 is in the non-operating position; FIG. 2 is a sectional view similar to FIG. 2, and FIG. 4 is a partially sectional top view of the brake control valve of FIG. 1;
2 is a sectional view taken along the line ``-'' of FIG. 4, FIG. 3 is a sectional view taken similarly along the line ``-'', and FIG. 5 shows the first and second outlets of the brake control valve. It is a graph showing the relationship between port pressures P ₁ and P ₂ and the angular position of the operating handle. In the figure, code 2...brake control valve,
8...Dual brake valve, 10...High pressure side outlet port, 12...Low pressure side outlet port, 14...Relay valve, 16...Spring brake chamber, 1
8... Inlet port, 20... First outlet port, 22
...Second outlet port, 28...Spring brake section, 30...Relay valve for trailer control, 32...
Service line, 36... Emergence line, 3
8...Exhaust port, 40...Operation handle, 42...First valve device portion, 44...First passage, 46...Second
passage, 48...second valve device portion, 96...valve mechanism, 98...operating device, 100...actuating member (protrusion).

Claims (1)

[Scope of Claims] 1. A tractor-side brake device portion equipped with a spring brake chamber operated by a dual brake valve, and a tractor-side brake device portion connected to the tractor-side brake device portion via a service line and an emergency line. A trailer control relay valve is also disposed in the tractor side brake device part, and the trailer control relay valve generates a pressure approximately equal to the outlet port pressure of the dual brake valve when the dual brake valve is operated. and transmits the pressure to the service line, and when the spring brake portion of the spring brake chamber is depressurized, an increased pressure proportional to the amount of pressure reduction is generated and the pressure is transmitted to the service line. and a brake control valve used in an air brake system for a trailer-coupled vehicle, an inlet port connected to an air tank, a first outlet port connected to a spring brake portion of the spring brake chamber, and an exhaust port communicating with the atmosphere. and an operating handle variably movable between an inoperative position and a fully operative position, the operating handle communicating the first outlet port with the inlet port when the operating handle is in the inoperative position; is in the fully operational position, the first
an outlet port in communication with the exhaust port, and when the operating handle is in an intermediate operating position between the non-operating position and the fully operating position, the first outlet port communicates with the exhaust port for operating the operating handle. a first valve device portion configured to reduce the pressure in the first outlet port in proportion to the amount of operation of the operating handle by communicating with the first outlet port in proportion to the amount of operation of the operating handle; a first passageway communicating with;
a second passage communicating with the inlet port; a second outlet port connected to the trailer control relay valve; a first position communicating the second outlet port with the first passage; and the second passage. a second valve arrangement portion comprising: a valve mechanism movable between a second position for communicating an outlet port of the valve with the second passage; and a second valve arrangement portion comprising an operating arrangement for operating the valve arrangement; The device includes an actuating member integral with the operating handle for maintaining the valve mechanism in the first position when the operating handle is in the non-operating position and the intermediate operating position, and for maintaining the valve mechanism in the first position when the operating handle is in the fully operating position. A brake control valve, wherein the brake control valve is configured to move the valve mechanism to the second position at certain times. 2. The valve mechanism of the second valve device portion is:
a valve body that is slidably supported in a sealed manner with respect to the housing by a valve stem portion on a side opposite to the valve face; a central hole is formed that can communicate with an outlet of the valve body, the operating device having a plunger movable coaxially with the valve body, and the valve mechanism also having a valve body of the valve body at an inner end of the plunger. a valve seat provided to face a surface, the valve surface and the valve seat forming a first seat valve that opens and closes the central hole; A valve seat is provided integrally with the housing so as to face a valve surface, and the valve surface and the valve seat of the housing are connected to a second passageway for opening and closing a communication passage between the second passageway and the second outlet port. constitutes a seat valve,
2. The brake control valve according to claim 1, wherein said valve body is elastically supported so as to normally close said second seat valve. 3. The valve body has the same shape and dimensions as a valve body used to control communication between the first outlet port and the inlet port and the exhaust port in the first valve device part. Brake control valve described in range 2. 4. The actuating member integrated with the operating handle is a projection protruding from the base of the operating handle, and the plunger has a small diameter part and a large diameter part, and the large diameter part is located within the housing. The small diameter portion is slidably supported by the housing in a sealed manner, the tip of the small diameter portion protrudes outward beyond the housing, and the valve seat is formed at the tip of the large diameter portion. said first seated valve comprising said first seated valve being held in an open position by pressure acting on the large diameter portion of said plunger, and a protrusion on said operating handle causing said first seated valve to open when said operating handle is moved to said fully operated position. engage the protruding tip and push it down,
4. The brake control valve according to claim 2, further comprising a cam surface that acts to close the first seat valve and simultaneously open the second seat valve.