JPH0479865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic brake operation device with a braking force holding device that can automatically maintain the brake in an activated state when a vehicle is stopped.

[Conventional technology]

Generally, in a vehicle, when the brake pedal is depressed, the brakes are activated and the vehicle is in a braking state, and when the brake pedal is released, the brake operation is released and the vehicle is in a non-braking state. Therefore, when the vehicle is temporarily stopped on a slope, etc., it is usually necessary to operate a separate braking system such as the handbrake, and when starting again, the handbrake must be released while the vehicle is being stopped. , operations that required skill such as operating the accelerator and clutch were required.

In recent years, automatic brake operating devices that have a braking force retention device, which frees drivers from such complicated operating methods and allows them to perform safe and simple driving operations, have been developed. Even if the brake pedal is later released, the brake automatically maintains its braking state, and when the vehicle starts, the brake is automatically released in conjunction with the depression of the accelerator pedal, allowing for a smooth start. An automatic brake operating device (see, for example, Japanese Utility Model Application No. 56-83557 and Japanese Patent Application Laid-Open No. 60-11719) has been developed which has a braking force holding device.

For example, Japanese Utility Model Application Publication No. 56-83557 discloses a hydraulic pressure holding device for an automobile brake as shown in FIG. This automotive brake fluid pressure holding device is installed in a brake fluid pressure piping system in a vehicle that does not have a clutch pedal, such as an electromagnetic clutch vehicle or a torque converter vehicle, so that the hydraulic pressure is supplied to the brake even when the brake pedal 10 is released when braking on an uphill road. A hydraulic pressure holding valve 17 that continues to hold the hydraulic pressure is provided, and the hydraulic pressure holding valve is configured to release the brake hydraulic pressure holding in conjunction with depression of the accelerator pedal 18. However, this hydraulic pressure holding device for automobile brakes, that is, an automatic brake operation device with a braking force holding device, is not necessarily sufficient in terms of precise and smooth control and reliability. There are problems.

Furthermore, an automatic brake operating device having a braking force holding device has been developed as shown in FIGS. 5, 6A, and 6B. This will be explained below with reference to the drawings.

FIG. 5 shows the piping system in the automatic brake operating device, in which the high-pressure air accumulated in the main air tank 6 by the air pump is divided into two systems, the primary side and the secondary side, and is once accumulated in the sub-air tank 5, and is then used to brake the air. Lines 12, 14 via valve 3
is supplied to the electromagnetically operated check valve 3. High-pressure air is passed from the discharge side of the electromagnetically operated check valve 8 to the pipe line 1.
3 and 15, and are supplied to the primary and secondary air masters 2, respectively, and move the pistons within the air masters 2. The movement of the piston activates the wheel cylinder and applies braking to the wheel. The high-pressure air in the main air tank 6 is configured so that it can pass through the brake valve 3 only when the brake pedal 10 is depressed, and the discharge side of the brake valve 3 communicates with the atmosphere when the brake pedal 10 is released. There is.

The electromagnetically operated check valve 8 is connected via a conduit 11,
High-pressure air is separately supplied, and in response to the opening and closing of the solenoid valve activated by a signal from the control device 4, a passage closing means provided in the electromagnetically operated check valve 8 is activated by the high-pressure air, pipe line 12 and pipe line 13,
and is configured to block communication between the pipe line 14 and the pipe line 15.

Next, the electromagnetically operated check valve 8 will be explained with reference to FIGS. 6A and 6B. Here, since the electromagnetically operated check valve 8 is bilaterally symmetrical, only the right half, that is, the primary side will be described.

The electromagnetically operated check valve 8 has a cylinder 21,
A piston 22 is provided within the cylinder 21. A valve body 24 is attached to the tip of the piston 22 via a pin 23. Both the locking hole 50 of the pin 23 formed at the tip of the piston 22 and the pin locking hole 25 formed in the valve body 24 are connected to the pin 23.
The diameter is slightly larger than the diameter of valve body 24.
is attached to the piston 22 so as to be able to move slightly in the axial direction.

Furthermore, the valve body 24 is always biased to the right in the figure by a spring 26 provided within the piston 22. A supply port 28 having a valve seat 27 is formed at the tip of the cylinder 21, and the supply port 28 is connected to the sub-air tank 5 via the aforementioned pipe 12 and brake valve 3 (see FIG. 5). . A discharge port 29 is further formed at the tip of the cylinder 21, and the discharge port 29 is connected to the air master 2 described above (see FIG. 5) via a conduit 13.

A spring 31 is provided in the pressure chamber 30 formed by the cylinder 21 and the piston 22, and the action of the spring 31 normally moves the piston 22 and the valve body 24 in the direction away from the valve seat 27. It is pressed to the position shown in Figure 6 A.

A solenoid valve 32 is attached to the center of the cylinder 21. The solenoid valve 32 has a solenoid 33 and a plunger 34, and the plunger 34 is connected to a rod 35 extending vertically downward. Below the rod 35, there are two
Two valve chambers 37 and 38 are provided, and two opposing valve bodies 39 are provided in the two valve chambers 37 and 38.
and 40 are arranged. And two valve bodies 39
and 40 are connected to each other by a rod 41, and the rods 35 and 41 are coaxially connected integrally via a connecting member 42.

A spring 43 is disposed within the valve chamber 38, and the action of the spring 43 causes the plunger 34 and the rod 3 to
5. A valve operating member 44 consisting of a connecting member 42, a valve body 39, a rod 41 and a valve body 40 is normally biased upward, and the valve chamber 38 and passage 36 are closed by the valve body 40. The valve chamber 37 communicates with an atmospheric chamber 46 at the rear of the piston 22 through a through hole 45 provided in the cylinder 21 , and the passage 36 communicates with an atmospheric chamber 46 at the rear of the piston 22 through an operating air passage 47 . It communicates with room 48. Further, the valve chamber 38 is connected to the high pressure air line 11 (see FIG. 5) via a supply port 49.

The operation of the electromagnetically operated check valve 8 is as follows. When the solenoid valve 32 is not energized, the valve operating member 44 is in the position shown in FIG. 6A. In that position, the valve body 40 causes the valve chamber 38 to
Communication between the valve chamber 37 and the passage 36 is cut off, and the atmospheric chamber 46 and the pressure chamber 48 at the rear of the piston 22 communicate with the atmosphere from the valve chamber 37 via the through hole 45 and the working air passage 47, respectively. Therefore, the piston 22 and the valve body 24 are urged to the most retracted position shown in FIG. 6A by the action of the spring 31.

By depressing the brake pedal 10, high pressure air flows from the conduit 12 through the supply port 28 into the pressure chamber 30 through the brake valve, and further into the pressure chamber 30 through the discharge port 2.
9, passes through the conduit 13, and flows into the air master 2. This results in a braking action. When the brake pedal 10 is released, the line 12 opens as usual.
is open to the atmosphere.

When the vehicle stops, a certain period of time later, the control device 4 issues a signal to turn on the solenoid valve 32. As a result, the high pressure air flows into the pressure chamber 48 and moves the piston 22, causing the valve body 24 to
The communication between the pipe line 12 and the pressure chamber 30 is cut off.
In this state, release the brake pedal 10 and
Even if the brake actuator 2 is connected to the atmosphere, the pipe 13 communicating with the brake actuator side is blocked from the atmosphere by the valve body 24, so the inside of the pipe 13 is maintained at a high pressure state. The brake will continue to be applied. Therefore, even if the brake pedal is released while the vehicle is temporarily stopped on a slope or the like, there is no risk that the vehicle will start moving on its own, and there is no need to pull the handbrake.

Further, when the accelerator or clutch is operated to start the vehicle, the control device 4 senses this and turns off the solenoid valve 32. When the solenoid valve 32 is turned off, the solenoid operated check valve 8 returns to the state shown in FIG. is opened to the atmosphere, the brake operation is released, and it is possible to start the vehicle. Therefore, there is no need to operate the accelerator or clutch while loosening the handbrake as in the conventional case.

The operation of the electromagnetically operated check valve 8 is as described above, but the following measures are further taken. That is,
Normally, in a vehicle brake system, when the brake is activated, a pressure approximately equal to the pressure in the main air tank 6 is generated in the air master 2 and the pipes 12 and 13, and if this state is maintained for a long time,
This causes problems such as seizure on the brake friction surface and mechanical damage on the sealing surface. for that,
In consideration of the need to maintain brake operation for a long period of time, a means is provided to maintain the pressure in high-pressure parts such as the air master 2 at a value lower than the pressure required for brake operation when the vehicle is running. .

Regarding what is shown in FIG. 6A and FIG. 6B, F1 = [air pressure P1 in the pressure chamber 48 x effective pressure receiving area S1 of the piston on the pressure chamber 48 side] and F2 =
Due to the difference F = F1 - F2 of [air pressure P2 in the pressure chamber 30 x effective pressure receiving area S2 of the piston on the pressure chamber 30 side + force f of the spring 31], the piston 22
While moving from the position shown in Figure A to the position shown in Figure 6B, a predetermined pressure drop occurs in the pipe line 13, and at the point when the communication between the pipe line 13 and the pipe line 12 is cut off, the brake actuator is activated. It is designed so that the pressure on the pipe line 13 side is maintained at a pressure value that does not cause problems such as seizure on the yuator side. That is, the piston 22
and the valve body 24 function as a kind of pressure regulating valve that can be balanced.

In the electromagnetically operated check valve 8, the brake pedal 10 is depressed to stop the vehicle, and after a certain period of time has elapsed, the electromagnetic valve 32 is turned on by a signal from the control device 4, and the high pressure air from the pipe line 11 flows into the pressure chamber 48.
Since the piston 22 and the valve body 24 are normally designed so that F1<F2 when the fluid flows into the air, the piston 22 and the valve body 24 remain at the open position shown in FIG. 6A, and the brake pedal 10 is gradually released. As a result, the pressure P in the pressure chamber 30 gradually decreases, and the piston 22 moves rightward in the figure, and after a predetermined pressure drop, it finally reaches the position shown in FIG. Communication between line 13 and conduit 12 is cut off.

[Problem to be solved by the invention] However, in the piping structure of the prior art, the electromagnetically operated check valve 8 is connected from the main air tank 6.
The valve body 24 cuts off communication between the pipe line 12 and the pipe line 13 due to the pressure of the high pressure air supplied to the supply port 49 of the brake actuator. The structure is such that it is maintained. That is, the value of the air pressure maintained on the brake actuator side is determined by the magnitude of the pressure of high pressure air from the main air tank 6.

Therefore, if the pressure in the main air tank 6 drops even slightly below the specified pressure, the pressure maintained within the pipe 13 will also drop, and as a result, a large braking force will not be obtained. For example, if the main air tank pressure is 8Kg/cm ² (specified pressure), the pressure maintained in the pipe 13 communicating with the brake actuator side will be 2Kg/cm ² . Main air tank pressure is 7Kg/
cm ² , the pressure maintained in pipe 13 is
The weight decreases to 1.75Kg/cm ² .

In addition, the electromagnetically operated check valve 8 is operated by high pressure air supplied from the main air tank 6 to the supply port 49 through one pipe 11, so that the left and right valve bodies 24, 24
moves to the position shown in FIG.
Thereby, the structure is such that the inside of the pipe line 13 and the pipe line 15 communicating with the brake actuator side are maintained in a high pressure state. Therefore, if a failure occurs at even one point in the conduit 11, the insides of the conduit 13 and conduit 15 will not be maintained at a high pressure state, and the brake actuator on the primary side will not act as the brake actuator on the secondary side. Both Yueta will also lose their function as braking force retention devices.

Furthermore, if the brake pedal 10 is suddenly released while the solenoid valve 32 is on,
The pipe line 12 is instantly opened to the atmosphere,
As a result, the pressure chamber 30 and the pipe line 13 are also instantly opened to the atmosphere, and the pressure on the brake actuator side, that is, inside the air master 2, decreases rapidly. Moreover, in order for the piston 22 and the valve body 24 to reach the line blocking position shown in FIG. 6B from the most retracted position shown in FIG. Yes, it takes a certain amount of time.

Therefore, when the brake pedal 10 is suddenly released, due to the relationship between the sudden pressure drop on the brake actuator side, that is, on the pipe line 13 and air master 2 side, and the time required for the valve body 24 to close. At the time when the communication between the pipe line 13 and the pipe line 12 was cut off by the valve body 24, there was a possibility that the pressure in the pipe line 13 and the air master 2 would already drop below a predetermined pressure.

In particular, if the brake is pressed strongly when stopping the vehicle on a slope such as a slope, the pressure value on the conduit 13 side may become higher, and in such a case, the brake pedal 10 may be suddenly depressed. If the brake actuator is released immediately, it is likely to cause an unnecessarily low pressure drop on the brake actuator side, which may result in the brakes not being able to "squeeze" too much, and depending on the inclination of the slope, the vehicle may start to move, potentially causing a serious accident. I was afraid it wouldn't happen.

Therefore, it may be possible to make the sliding resistance of the piston 22 extremely small, but in that case, the piston 22 would react sensitively to the air pressure in the main air tank, causing the main air tank pressure to drop. In this case, the phenomenon of a decrease in the pressure maintained within the conduit 13 becomes noticeable.

As mentioned above, the above problem arises because the electromagnetically operated check valve 8 is structured so that the amount of pressure maintained on the brake actuator side is controlled by the high pressure air supplied from the main air tank 6. This is due to the fact that

The purpose of this invention is to solve the above problems, and to control the pressure held on the brake actuator side to a predetermined value using air pressure supplied from the brake valve. The automatic brake operating device with a braking force holding device is characterized in that the holding pressure does not decrease due to changes in the main air tank pressure, and it is not affected by the sliding resistance of the piston in the electromagnetic operated check valve as in the past. It is to provide.

[Means for solving problems]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention provides an automatic brake operating device with a braking force holding device that includes a closing means for holding air pressure from an air source and acting on a brake actuator by operating a brake valve, wherein the closing means is A first passage and a second passage that enable communication between the brake valve and the brake actuator, a solenoid valve that selectively communicates or blocks the first passage and the second passage, and an air pressure in the first passage. a valve device that opens the second passage when the air pressure is below a predetermined value and closes the second passage when the predetermined value is exceeded; The present invention relates to an automatic brake operating device with a braking force holding device characterized by having a double check valve that communicates a second passage with a discharge port.

Further, in this automatic brake operation device with a braking force retention device, the closing means maintains the pressure on the brake actuator side at a pressure lower than the pressure required for brake operation when the vehicle is running.

Further, in this automatic brake operating device with a braking force holding device, the closing means constitutes a slope stop/start valve.

Moreover, in this automatic brake operating device with a braking force retention device, the slope stop/start valve is configured integrally with a primary side valve and a secondary side valve symmetrically.

[Effect]

The automatic brake operating device with a braking force holding device according to the present invention is constructed as described above and operates as follows. That is, when the solenoid valve is in the off state, the first passage and the second passage are not in communication, but when the solenoid valve is in the on state,
The first passage and the second passage are in communication. At this time, if the air pressure supplied into the first passage from the supply port is below a predetermined value, the second passage is opened by the action of the valve device, so the air pressure in the first passage is The air pressure in the second passage is equal. Therefore, the discharge port and the second passage communicate with each other due to the function of the double check valve. Eventually, the air flowing into the supply port from the brake valve is supplied to the air master through the first passage, the second passage, and the discharge port.

When the air pressure supplied into the first passage from the supply port exceeds a predetermined value, the valve device operates to close the second passage, and a predetermined value of air pressure is maintained in the second passage. Therefore, the air pressure in the first passage becomes higher than the air pressure in the second passage. Therefore, the discharge port and the first passage communicate with each other due to the action of the double check valve.

Eventually, the air flowing into the supply port from the brake valve is supplied to the air master through the first passage and the discharge port, while a predetermined value of air pressure is maintained in the second passage. .

When the brake pedal is released in this state, the air in the air master passes through the first passage and exits from the brake valve to the atmosphere. When the air pressure in the first passage reaches a predetermined value, the air pressure in the first passage and the second passage become equal, so that the discharge port and the second passage communicate with each other due to the action of the double check valve. Since the second passage is closed by the valve device, a predetermined air pressure is maintained from the air master to the second passage.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic brake operating device with a braking force holding device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a piping system in an automatic brake operating device with a braking force holding device according to the present invention. Main air tank 6 by air pump
The high pressure air accumulated in is divided into two systems, a primary side and a secondary side, and is supplied to the sub air tank 5 and the brake valve 3. The slope stop/start valve 1 serving as a closing means discharges air supplied from the brake valve 3 through the pipe line 12 to the pipe line 13, and discharges air supplied from the brake valve 3 via the pipe line 14 to the pipe line 15. Exhale. The air discharged from the conduit 13 is supplied to the air master 2 on the primary side, and the air discharged from the conduit 15 is supplied to the air master 2 on the secondary side, and a piston (not shown) in each air master 2 is supplied. move. Then, the movement of the piston causes the wheel cylinder to operate and brake the wheel (not shown).

The air pressure switch 7 includes a conduit 12 connecting the slope stop/start valve 1 and the brake valve 3;
14, and when the brake pedal 10 is released, the brake valve 3 communicates with the atmosphere and is turned on. The signal at this time is control device 4
sent to. The control device 4 sends a signal to turn on the solenoid valve 90 of the hill stop/start valve 1 after a certain period of time after the vehicle has stopped. The stop lamp is configured to light up only when a signal from the air pressure switch 7 is input to the control device 4 and the solenoid valve 90 is in the on state.

Next, the slope stop/start valve 1 as a closing means
The specific structure of will be explained with reference to FIGS. 2 and 3. The slope stop/start valve 1 has a symmetrical structure with respect to the line -, with the right side, shown in FIG. 3, being the primary side, and the left side, shown in FIG. 2, being the secondary side. FIG. 2 shows the secondary slope stop/start valve 1 with the solenoid valve 90 in an OFF state, and FIG. 3 shows the primary slope stop/start valve 1 with the solenoid valve 90 in an ON state.

This slope stop/start valve 1 consists of a solenoid valve 90, a valve device (a double check valve 91 and an air valve 92), a check valve 93, and a supply port 94 connected to conduits 12 and 14 connected to the brake valve 3; and a discharge port 95 connected to the pipe lines 13 and 15 connected to the air master 2. Further, the slope stop/start valve 1 is connected to the first passage A.
and second passages B, D, E, F (upper chamber B, chamber D,
It has a room E and a passage F).

The solenoid valve 90 has a solenoid 101 and a plunger 102, and the plunger 102 is connected to a rod 103 extending vertically downward. A piston 104 is provided below the rod 103, and this piston 104 connects a rod 107 to a valve body 106 disposed in a valve chamber 105. A spring 108 is disposed within the valve chamber 105, and a plunger 102, a rod 103,
Valve operating member 110 consisting of piston 104, valve body 106, rod 107 and diaphragm 109
is normally biased upward by the action of spring 108. Note that the diaphragm 109 is connected to the valve chamber 10.
5 is divided into an upper chamber B and a lower chamber C.

When the solenoid valve 90 is in the off state, the valve body 1
06 is in contact with the upper valve seat 111 and the valve chamber 105
At the same time, the lower chamber C of the supply port 9 is communicated with the atmosphere.
The communication between the first passage A that communicates with the upper chamber B and the upper chamber B is cut off.

Further, when the solenoid valve 90 is in the on state,
The valve operating member 110 moves downward, and as it moves, the valve body 106 comes into contact with the lower valve seat 112 to cut off communication between the lower chamber C and the atmosphere, and at the same time, connect the upper chamber B and the first passage A. to contact you.

The double check valve 91 is the piston valve 11
3 and a spring 114 that urges the piston valve 113 upward. If the air pressure in the first passage A is a, and the air pressure in the second passage F is f, then when a>f, air flows from the first passage A toward the air master 2, and when a≦f. At times, air flows from the second passageway F towards the air master 2.

The air valve 92 includes two valve bodies 116 and 117 connected by a rod 115 and a valve body 116,
It consists of a spring 119 disposed in the chamber 118 to urge the chamber 117 upward and a diaphragm 120 that divides the chamber 118 into upper and lower halves. When the pressure of the air supplied from the brake valve 3 to the chamber 118 is less than 2 kg/cm ² , the valve element 117 is separated from the valve seat 121, but when it exceeds 2 kg/cm ² , the valve element 117 is separated from the valve seat 121.
7 comes into contact with the valve seat 121. Note that the lower chamber of chamber 118 communicates with the atmosphere.

The check valve 93 is arranged between the valve body 122 and the chamber E, and urges the valve body 122 upward to remove the valve seat 123.
The spring 124 is brought into contact with the spring 124. If pressure is applied from chamber D to chamber E while the valve body 117 of the air valve 92 is away from the valve seat 121, the valve body 122 can be moved away from the valve seat 123 against the force of the spring 124.

Next, the slope stop/start valve 1 incorporated in the automatic brake operating device with a braking force holding device of the present invention will be described.
The operation of this will be explained. As shown in Figure 2,
When the solenoid valve 90 is in the off state, the valve body 10
6 contacts the upper valve seat 111 to shut off the upper chamber B and the first passage A, and at the same time separates from the lower valve seat 112 to open the lower chamber C to the atmosphere.

When the brake pedal 10 is depressed in this state, the air supplied from the brake valve 3 is transferred to the supply port 94.
The air flows into the passage A, and the air pressure a of the passage A and the passage F
Since a relationship a>f is created between the air pressure f of
more discharged. In this way, normal brake operation is performed.

When the pressure of the air supplied from the brake valve 3 exceeds 2 kg/cm ² , the air pressure causes the valve body 117 of the air valve 92 to come into contact with the valve seat 121 and cut off communication between the chambers D and E. The air pressure in chamber E and passage F will be 2 kg/cm ² . Therefore, since the relationship between the air pressure a in the passage A and the air pressure f in the passage F is a>f, the piston valve 113 of the double check valve 91 blocks communication between the passage F and the discharge port 95,
Air flows from passage A to air master 2 through discharge port 95. At the same time, the air pressure in chamber E and passage F is maintained at 2 kg/cm ² .

As shown in FIG. 3, when the solenoid valve 90 is in the on state, the valve body 106 comes into contact with the lower valve seat 112, thereby cutting off communication between the lower chamber C and the atmosphere, and at the same time, the upper chamber C is turned on. B and passage A communicate with each other.

When the brake pedal 10 is depressed, the air supplied from the brake valve 3 flows through the supply port 94 to the passage A.
and further flows into chamber D through upper chamber B. When the pressure of the air supplied from the brake valve 3 is 2 kg/cm ² or less, the force of the spring 119 is stronger than the pressure acting on the valve body 116 of the air valve 92, so the valve body 117 separates from the valve seat 121. ,
At the same time, the valve body 122 of the check valve 93 also
24 and separates from the valve seat 123, the air that has flowed into the chamber D further flows into the chamber E and the passage F.

At this time, air pressure a in passage A and air pressure f in passage F
Since the relationship is a=f, the piston valve 113 of the double check valve 91 moves upward, so that the air flowing into the passage F further passes through the discharge port 95.
and is supplied to the air master 2 via pipes 13 and 15. After all, if the pressure of the air supplied from the brake valve 3 is less than 2 kg/cm ² , the air will flow from the supply port 94 to the passage A to the upper chamber B to the chamber D.
→Chamber E → Passage F → Flows to discharge port 95.

When the brake pedal 10 is released and the brake valve 3 is opened to the atmosphere, air flows from the air master 2 to the discharge port 95. However, until the air pressure in the first passage A reaches 2 kg/cm ² , air in the passage A is released. Since the pressure a and the air pressure f in the passage F have a relationship of a>f, the discharge port 95 and the passage A remain in communication, so that the air flowing from the air master 2 to the discharge port 95 is It exits through passage A to brake valve 3. At this time, since the piston valve 113 of the double check valve 91 blocks communication between the discharge port 95 and the passage F, the air pressure in the chamber E and the passage F is 2.
remains at Kg/ ^cm2 .

When the air pressure flowing from the air master 2 to the discharge port 95 reaches 2 kg/cm ² , the air pressure a in the passage A and the passage F
Since the air pressure f is in the relationship a=f, the piston valve 113 of the double check valve 91 cuts off communication between the discharge port 95 and the first passage A, and
and passage F are communicated. Therefore, the air that has flowed into the discharge port 95 flows into the passage F.

At this time, the valve body 122 of the check valve 93 comes into contact with the valve seat 123 and the communication between the chambers E and D is cut ^off . air pressure is maintained. When air is further released from the brake valve 3 to the atmosphere and the air pressure in the first passage A becomes 2 kg/cm ² or less, the lower valve body 117 of the air valve 92 separates from the valve seat 121, but the check valve 93 closes the chamber D. Communication with room E remains blocked. Therefore, even if the brake pedal 10 is released while the vehicle is temporarily stopped on a slope or the like, there is no risk that the vehicle will start moving on its own.

When the accelerator pedal is depressed, the control device 4 senses this and turns off the solenoid valve 90. Solenoid valve 90
When the valve is turned off, the valve operating member 110 moves upward as shown in FIG. 2, and the communication between the upper chamber B and the passage A is cut off by the valve body 106. At the same time, the lower chamber C is communicated with the atmosphere, so that the air held therein from the chamber E and passage F to the air master 2 is released to the atmosphere. As a result, the brake is released.

〔Effect of the invention〕

The automatic brake operating device with a braking force holding device according to the present invention is configured as described above, and has the following effects. In other words, since the slope stop/start valve is used as a closing means that is activated by high pressure air supplied from the main air tank when the brake valve is activated, it is held on the air master side when temporarily stopped on a slope etc. A predetermined value of air pressure can always be maintained without being affected by a drop in air pressure in the main air tank.

In addition, in the electromagnetically operated check valve in the prior art, a pressure difference occurs between the discharge port side and the supply port side due to the sliding resistance of the valve body. There was a problem that the air pressure sent from the check valve to the air master was smaller, and as a result, a sufficiently large braking force could not be obtained.However, in the slope stop/start valve as the closing means in this invention, Because the double check valve allows air to flow directly from the brake valve to the air master or brake actuator, there is no pressure differential between the brake actuator and the brake valve.

Therefore, since the output pressure of the brake valve is directly output to the brake actuator, there is an advantage that a reliable and sufficiently large braking force can be obtained compared to the prior art.

Furthermore, since the slope stop/start valve incorporated in the automatic brake operation device with brake force holding device according to the present invention has a structure in which a double check valve, a solenoid valve, an air valve, and a check valve are assembled into one piece, it is easy to assemble it into the piping system. can be done easily. Further, since the pipe line from the main air tank used in the electromagnetically operated check valve in the prior art is not required, there is an advantage that the piping structure is simple.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the piping system of an automatic brake operating device with a braking force holding device according to the present invention;
3 and 3 are cross-sectional views of a slope stop/start valve used in an automatic brake operating device with a braking force retention device, FIG. 4 is a schematic diagram showing the piping system of a conventional automatic brake operating device with a braking force retention device, and FIG. Figure 5 is a schematic diagram showing the piping system of the prior art automatic brake operating device with braking force holding device, and Figures 6A and 6B show the electromagnetically operated check valve used in the piping system of Figure 5. FIG. 1...Slope stop/start valve (closing means), 2...
... Air master, 3 ... Brake valve, 4 ... Control device, 6 ... Main air tank, 90 ... Solenoid valve, 91 ... Double check valve, 92, 93
... Valve device, 94 ... Supply port, 95 ... Discharge port, A ... First passage, B, D, E, F ... Second passage (B is the upper chamber, D and E are the chambers, F is aisle), C...
...lower chamber.

Claims (1)

[Scope of Claims] 1. An automatic brake operation device with a braking force holding device, which includes a closing means for holding air pressure from an air source and acting on a brake actuator by operating a brake valve, wherein the closing means comprises: A first passage and a second passage that enable communication between the brake valve and the brake actuator, a solenoid valve that selectively communicates or blocks the first passage and the second passage, and air pressure in the first passage. a valve device that opens the second passage when the air pressure is below a predetermined value and closes the second passage when the air pressure exceeds the predetermined value; An automatic brake operating device with a braking force retention device, comprising a double check valve that communicates the second passage with the discharge port. 2. The braking force according to claim 1, wherein the closing means maintains the pressure on the brake actuator side at a pressure lower than the pressure required for brake operation when the vehicle is running. Automatic brake operating device with holding device. 3. The automatic brake operating device with a braking force holding device according to claim 1, wherein the closing means is a slope stop/start valve. 4. The automatic brake operating device with a braking force holding device according to claim 3, wherein the slope stop/start valve is configured integrally with a primary side valve and a secondary side valve symmetrically.