JPH08113140A - Protective device of vane type vacuum pump for diesel engine - Google Patents

Abstract

PURPOSE: To prevent the suction of a lubricating oil by a vacuum pump through an exhaust port. CONSTITUTION: A vane type vacuum pump 3 provided in an engine 15, operated by the engine 15 to suck the air in spaces 46 and 47 at the front side and the rear side in a booster 32, and to exhaust the air in the engine 15 so as to make the spaces 46 and 47 at the front side and the rear side in the same negative pressure, is provided. A switch valve 70 to open the rear side space 47 to the atmosphere depending on the depressing of a brake pedal 54, and to make the front side and the rear side spaces 46 and 47 at the same negative pressure by the vane type vacuum pump 3, depending on releasing the depressing of the brake pedal 54, is provided. And a throttle valve 71 to connect the vane type vacuum pump 3 to the atmosphere through the switch valve 70 so as to suck a minute amount of air, when the brake pedal 54 is not depressed, is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for a vane vacuum pump for a diesel engine, and more particularly, to a vane vacuum device provided in a diesel engine and operated by the diesel engine to suck air in a brake booster. The present invention relates to a protection device for a pump.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 5 to 7, a brake booster 1 for operating a brake system in a diesel vehicle 15 is mounted on a vehicle. A vacuum pump 3 is connected to the brake booster 1 via a connecting pipe 2 for sucking the air in the brake booster 1. The vacuum pump 3 is a vane type vacuum pump, and a circular housing space 5 is formed in the pump housing 4. A rotor 6 is rotatably arranged at a position offset from the center of the arrangement space 5. Further, a plurality of accommodating portions 7 are formed in the radial direction of the rotor 6. A blade 9 is slidably disposed in the accommodating portion 7 along the accommodating portion 7, and the tip of the blade 9 always slides on the inner peripheral surface of the disposing space 5. A plurality of (four in this case) space portions 10 are defined by the blade 9 in the arrangement space portion 5.

The pump housing 4 has a connecting pipe 2
A suction port 12 and a discharge port 13 connected to are formed. Since the rotor 6 is offset from the center of the installation space portion 5, when the rotor 6 rotates due to the rotation of the gear 14 in the vacuum pump 3, the blade 9
The volume of the space portion 10 partitioned and formed is changed.

Therefore, the air sucked from the suction port 12 is sucked into the space 10 and then discharged to the outside through the discharge port 13. As a result, the inside of the brake booster 1 becomes a negative pressure due to the operation of the vacuum pump 3.

The vacuum pump 3 is attached to the diesel engine 15. That is, the diesel engine 15 includes an engine body 15a, a gear case cover 17 that covers the front and bottom surfaces of the engine body 15a, and an oil pan 20. The vacuum pump 3 is attached to a gear case cover 17. Then, the gear 1 of the vacuum pump 3 is connected to the idle gear 16 which is rotated by the operation of the diesel engine 15.
4 is meshed. Also, the idle gear 16 and the gear 1
4 below the gear case cover 17 that covers the oil pan 2.
0 is attached and the lubricating oil 21 is stored. The discharge port 13 formed in the pump housing 4 of the vacuum pump 3 is in communication with the inside of the diesel engine 15, that is, the inside of the gear case cover 17 and the oil pan 20.

When the diesel engine 15 operates, the lubricating oil 21 stored in the oil pan 20 circulates. A part of the lubricating oil 21 flows down along the surface of the engine body 15a, and the idle gear 16 and the gear 14
Will be supplied to.

[0007]

By the way, when the vacuum pump 3 sucks the air inside the brake booster 1, the air from the space portion 10 connected to the discharge port 13 is removed as shown by the dotted arrow in FIG. Air is discharged into the diesel engine 15 via the discharge port 13. However, when the inside of the brake booster 1 becomes a negative pressure and there is nothing to suck, the space 10 of the vacuum pump 3 also becomes a negative pressure. When the space 10 having a negative pressure communicates with the inside of the diesel engine 15 through the discharge port 13, the lubricating oil 21 and the gear case cover fall along the inner side surface of the gear case cover 17 as indicated by the solid arrow. The lubricating oil 21 floating in 17 is sucked into the space 10.

Then, the volume of the space 10 connected to the discharge port 13 by the rotor 6 and the blade 9 is further compressed. At this time, the lubricating oil 21 sucked into the space 10 via the discharge port 13 is compressed. However, the lubricating oil 21
Since it cannot be compressed unlike air, the lubricating oil 21 that cannot be compressed forcibly slides the blade 9 against the urging force of the spring 8 and tries to move to the outside of the space 10.

Therefore, there is a problem that the blade 9 is worn, the suction / discharge efficiency of the vacuum pump 3 is deteriorated, and the life of the vacuum pump 3 is shortened. Further, when the diesel engine 15 is rotating at a high speed, the circulation amount of the lubricating oil 21 becomes large, so that there is a problem that the lubricating oil 21 is easily sucked into the space 10 via the discharge port 13 of the vacuum pump 3. .

As a countermeasure against this, it is conceivable to increase the number of blades 9 provided on the rotor 6 to reduce the volume of each space portion 10 to reduce the compression rate. However, if the number of blades 9 is increased, the vacuum pump 3
There is a problem that not only the number of parts for assembling the pump becomes large, but also the work for assembling the vacuum pump 3 becomes very troublesome.

The present invention has been made to solve the above problems. A first object of the present invention is to prevent a vacuum pump from sucking lubricating oil through a discharge port so as to prevent suction.
It is an object of the present invention to provide a vane vacuum pump protection device for a diesel engine, which can improve the discharge efficiency, prolong the life, prevent the increase in the number of parts, and facilitate the assembling work.

A second object is to provide a vane vacuum pump protection device for a diesel engine which can prevent the vacuum pump from sucking the lubricating oil through the discharge port only when the circulating amount of the lubricating oil is large. To provide.

A third object is a diesel engine which does not affect the operation of the brake booster, prevents the vacuum pump from sucking the lubricating oil through the discharge port, and can suppress the generation of blow-by gas as much as possible. An object is to provide a protection device for a vane vacuum pump for an engine.

[0014]

In order to solve the above problems, the invention according to claim 1 uses a front spring for moving a piston which is divided into a front space portion and a rear space portion to the rear space portion. A booster arranged in the side space and a diesel engine, which is operated by the diesel engine to suck air in the front or front and rear side spaces and discharge the air from a discharge port to front or A vane-type vacuum pump with negative pressure in the front and rear spaces, and open the rear space to the atmosphere when the brake pedal is depressed, and vane the front and rear spaces when the brake pedal is released. The switching valve that keeps the same negative pressure with the vacuum pump and the vane through the switching valve when the brake pedal is not depressed. The vacuum pump is connected to the atmosphere, and its gist that a throttle valve for sucking a small amount of air.

According to a second aspect of the present invention, a booster in which a spring for moving a piston, which is divided into a front side space portion and a rear side space portion, to the rear side space portion is arranged in the front side space portion, and a booster provided in the diesel engine, are arranged in the diesel engine. A vane vacuum which is installed and operates by the diesel engine to suck air in the front or front and rear side spaces and discharge the air from a discharge port to make the front or front and rear side spaces a negative pressure. A switching valve that connects the pump and the space on the rear side to the atmosphere based on the depression of the brake pedal, and turns the front or front and rear spaces to a negative pressure by suction of the vane vacuum pump based on the release of the depression on the accelerator pedal. And the brake detection means to detect the depression of the brake pedal and the vane type vacuum pump. When the brake pedal is not depressed based on the detection signal from the brake detection means and the switching valve that connects to the air to suck air, the switching valve is controlled to open and close to connect the vane vacuum pump to the atmosphere. The gist of the present invention is to include a switching valve control means for sucking a small amount of air.

According to a third aspect of the present invention, the engine speed detecting means for detecting the engine speed of the diesel engine is provided, and the engine speed is predetermined based on the detection signal from the engine speed detecting means. When the brake pedal is not stepped on based on the detection signal from the brake detection means, the switching valve control means controls the opening and closing of the switching valve to connect the vane vacuum pump to the atmosphere and to release a small amount of air. The point is to make it suck.

[0017]

According to the first aspect of the invention, the front and rear spaces of the booster are connected to the vane vacuum pump via the switching valve when the brake pedal is not depressed. When the diesel engine operates in this state, the vacuum pump sucks the air in the front and rear spaces to make the same negative pressure. Then, the vacuum pump discharges the sucked air into the diesel engine through the discharge port. Since the front and rear space parts have the same negative pressure, the piston is moved to the rear space part by the biasing force of the spring, and the braking operation is not performed. When the brake pedal is depressed in this state, the switching valve opens the rear side space of the booster to the atmosphere, so that a pressure difference is generated between the front side space and the rear side space. Therefore, the piston moves to the front space and the braking operation is performed.

On the other hand, when the brake pedal is not depressed, the vane type vacuum pump is connected to the atmosphere via the throttle valve. Therefore, the vane vacuum pump sucks a small amount of air through the throttle valve. Therefore,
The vane type vacuum pump compresses a small amount of air sucked through the throttle valve and discharges the compressed air into the diesel engine through the discharge port. Therefore, it is possible to prevent the vacuum pump from sucking the lubricating oil that lubricates the diesel engine. In addition, since the amount of sucked air is very small, the amount of air discharged from the discharge port into the diesel engine is also very small.

According to the second aspect of the invention, the front and rear spaces of the booster are connected to the vane vacuum pump via the switching valve when the brake pedal is not depressed. When the diesel engine operates in this state, the vacuum pump sucks the air in the front and rear spaces to make the same negative pressure.
Then, the vacuum pump discharges the sucked air into the diesel engine through the discharge port. Since the front side space and the rear side space have the same negative pressure, the piston is moved to the rear side space by the biasing force of the spring, and the braking operation is not performed. When the brake pedal is depressed in this state, the switching valve opens the rear side space of the booster to the atmosphere, so that a pressure difference is generated between the front side space and the rear side space. Therefore, the piston moves to the front space and the braking operation is performed.

On the other hand, when the switching valve control means determines that the brake pedal is not stepped on the basis of the detection signal from the brake detection means, the switching valve control means controls the opening / closing of the switching valve. Therefore, the vane vacuum pump sucks a small amount of air when the switching valve is controlled to be opened. Therefore, the vane vacuum pump compresses a small amount of air sucked through the throttle valve and discharges it from the discharge port to the inside of the diesel engine. Therefore, it is possible to prevent the vacuum pump from sucking the lubricating oil that lubricates the diesel engine. Further, when the brake pedal is depressed, the opening / closing control of the switching valve is stopped, so that it is possible to prevent the operation of the booster from being adversely affected. Moreover, since the amount of air sucked by the vacuum pump is very small, the amount of air discharged from the discharge port into the diesel engine is also very small.

According to the third aspect of the present invention, the switching valve control means controls the opening and closing of the switching valve when the engine speed is high, the lubricating oil circulation amount is large, and the brake pedal is not depressed. Connect a vacuum pump to the atmosphere. Then, a small amount of air is sucked by the vacuum pump. Therefore, when the amount of lubricating oil is large, it is possible to prevent the vane vacuum pump from sucking the lubricating oil. Further, since the switching valve opening / closing control is performed only when the engine speed is high and the brake pedal is not depressed, it is possible to reduce the opening / closing control of the switching valve to reduce the amount of air to be sucked. It will be possible.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. The vacuum pump and the brake booster have basically the same configurations as those of the conventional technique, and therefore, the same reference numerals are used in the description.

As shown in FIG. 1, a vehicle 25 is equipped with a diesel engine 15. A vane type vacuum pump (hereinafter, simply referred to as a vacuum pump) 3 is provided inside a diesel engine (hereinafter, simply referred to as an engine) 15, and the vacuum pump 3 is operated by the operation of the engine 15. ing.
The vacuum pump 3 is connected to the brake booster 1 via a connection pipe 2.

Further, the vehicle 25 is equipped with a master cylinder 26 as a brake device for decelerating or stopping the vehicle 25. A brake piston 27 is arranged in the master cylinder 26. A first hydraulic chamber 28 and a second hydraulic chamber 29 are formed in the master cylinder 26 by the brake piston 27. Master cylinder 2
The first hydraulic chamber 28 of No. 6 is connected to a brake device (not shown) provided on each wheel 30 of the vehicle 25.

The brake booster 1 comprises a switching valve 31 and a booster 32. A diaphragm 33 is provided inside the switching valve 31, and a valve member 34 that moves up and down is provided at the center of the diaphragm 33. The lower end of the valve member 34 projects outside the lower end of the switching valve 31.
A communication hole 35 is formed at the upper end of the valve member 34.

Due to the diaphragm 33 and the valve member 34, the switching valve 31 has a first compartment 36 and a second compartment 37.
Are formed respectively. The switching valve 31 is formed with a connection hole 40 that connects the outside with the first compartment 36. Further, a valve body 41 is provided in the first compartment 36 so as to close the connection hole 40 to partition it from the outside or open the connection hole 40 to communicate with the outside.

A piston 45 is arranged in the booster 32, and a front space 46 and a rear space 47 are formed in the booster 32 by the piston 45. Here, the direction in which the piston 45 moves during the braking operation is the front side, and the direction in which the piston 45 moves during the release of the braking operation is the rear side. The piston 45 is installed in the front space 46 and the rear space 47 is
A spring 49 is arranged to urge it to move to the side. The piston 45 is provided with a piston rod 50,
The piston rod 50 is connected to the brake piston 27 of the master cylinder 26.

The second compartment 37 of the switching valve 31 and the front space 46 of the booster 32 are connected to the vacuum pump 3 via the connecting pipe 2. Also, the switching valve 3
The 1st 1st division room 36 is connected to the rear side space part 47 through the communicating pipe 51.

A brake pedal 54 is provided on the driver's seat of the vehicle 25. The brake pedal 54 is provided with hydraulic piping 55. The hydraulic pipe 55 is connected to the second hydraulic chamber 29 of the master cylinder 26. Further, the hydraulic pipe 55 is provided with a branch pipe 56, and the opening end 56 of the branch pipe 56 is provided.
The lower end of the valve member 34 of the switching valve 31 is inserted in a.

The hydraulic pipe 55, the branch pipe 56, and the first and second hydraulic chambers 28 and 29 of the master cylinder 26 are filled with hydraulic oil 58. Therefore, when the brake pedal 54 is depressed, pressure is applied to the hydraulic oil 58.

When the brake pedal 54 is not depressed, the valve member 34 descends and is separated from the valve element 41. At this time, the valve body 41 closes the connection hole 40 to partition the outside from the first partitioned chamber 36. Further, the first partition chamber 36 and the second partition chamber 37 communicate with each other through the communication hole 35 of the valve member 34.

In this state, if the vacuum pump 3 is operated by the diesel engine 15, the first and second compartments 36 and 37 will have the same negative pressure. Therefore, the front and rear space portions 46 and 47 of the booster 32 also have the same negative pressure. Therefore, the front and rear space portions 46, 47
Since there is no pressure difference between the two, the piston 45 moves to the rear space 47 side by the urging force of the spring 49. Therefore, the brake piston 27 is connected via the piston rod 50.
Also moves to the second hydraulic chamber 29 side. As a result, no pressure is applied to the hydraulic oil 58 on the side of the first hydraulic chamber 28, so the brake device provided on each wheel 30 of the vehicle 25 does not operate.

On the other hand, when the brake pedal 54 is depressed, pressure is applied to the hydraulic oil 58, so that the master cylinder 2
The brake piston 27 of No. 6 moves to the first hydraulic chamber 28 side. Therefore, pressure is applied to the hydraulic oil 58 in the first hydraulic chamber 28. Further, when pressure is applied to the hydraulic oil 58, the valve member 34 rises and pushes the valve body 41 upward. Then, the communication hole 35 of the valve member 34 is closed by the valve body 41, and the connection hole 40 is opened by the valve body 41 so that the first partitioned chamber 36 is connected to the outside.

Therefore, the rear side space portion 47 of the booster 32 is
Is connected to the first compartment 36 via the communication pipe 51, so that the rear side space 47 is at atmospheric pressure. Further, since the front side space portion 46 is connected to the vacuum pump 3 via the connection pipe 2, the front side space portion 4 is
6 is negative pressure.

As a result, the piston 45 moves to the front space 46 side against the biasing force of the spring 49 due to the pressure difference between the front space 46 and the rear space 47. By this movement of the piston 45, the brake piston 27 is further moved to the second hydraulic chamber 28 side via the piston rod 50.
Therefore, the hydraulic oil 58 in the second hydraulic chamber 28 is further pressurized so that the brake device mounted on the vehicle 25 operates.

The connection pipe 2 is provided with a switching valve 60. The switching valve 60 is provided with a pipe 61. The connection pipe 2 and the pipe 61 are connected by the operation of an electromagnetic valve (not shown) provided in the switching valve 60, and the connection pipe 2 is connected to the outside. or,
When the operation of the solenoid valve stops, the connecting pipe 2 and the pipe 61
Are separated from each other, and the connection pipe 2 is cut off from the outside.

The switching valve 60 is connected to a controller 62 as a switching valve control means, and the controller 62 controls the electromagnetic valve of the switching valve 60 to open / close the switching valve 60. The controller 62 includes a rotation speed sensor 63 as engine speed detection means for detecting the engine speed of the diesel engine 15 and a brake pedal sensor 64 as brake detection means for detecting depression of the brake pedal 54. Connected.

Further, the controller 62 includes a timer circuit 6
5 are provided. The timer circuit 65 operates the switching valve 60 to set an opening time for connecting the connection pipe 2 to the outside and counts the time, and sets a closing time for stopping the switching valve 60 to shut off the connection pipe 2 from the outside and its setting. It is designed to count time. In this embodiment, the opening time is 3 seconds and the closing time is 5 minutes.

Further, the controller 62 is a rotation speed sensor 63.
Based on the detection signal from the engine, the engine speed of the diesel engine 15 is a predetermined speed (2 in this embodiment).
000 rpm) or more. Then, the controller 62 determines the brake pedal 5 based on the detection signal from the brake pedal sensor 64.
It is designed to judge whether or not 4 is depressed.

The engine speed of the diesel engine 15 is 2000 based on the detection signal from the speed sensor 63.
When the controller 62 determines that the brake pedal 54 is not depressed based on the detection signal from the brake pedal sensor 64, the controller 62 operates the switching valve 60 for 3 seconds to connect the connection pipe 2 to the pipe. It is designed to be connected to the outside through 61.

At this time, a very small amount of air is sucked into the connection pipe 2 and the negative pressure in the connection pipe 2 is reduced, but the negative pressure in the brake booster 1 substantially affects the function of the brake booster 1. It is suppressed to the extent that does not come out. This is because when a large amount of air is taken into the connection pipe 2, the negative pressure in the brake booster 1 decreases. If the brake pedal 54 is depressed in this state, the pressure difference between the front side space portion 46 and the rear side space portion 47 of the booster 32 becomes small, and it becomes difficult to move the piston 45 to the front side space portion 46.

After the switching valve 60 is operated for 3 seconds based on the count of the timer circuit 65, it is counted for 5 minutes based on the count of the timer circuit 65. After 5 minutes, the engine speed is 2000 rpm or more. If the brake pedal 54 is not depressed, the controller 62 again operates the switching valve 60 for 3 seconds.

Further, a very small amount of air sucked into the connection pipe 2 is sucked into the vacuum pump 3, compressed and discharged into the diesel engine 15 through the discharge port 13. That is, the air sucked by the vacuum pump 3 is compressed, so that an air flow is generated from the discharge port 13 to the outside.

When the vacuum pump 3 is operated by the operation of the engine 15, the air in the brake booster 1 is sucked through the connecting pipe 2. At this time, as shown in FIG. 2, unless the brake pedal 54 is depressed, the first and second compartments 36, 37 of the switching valve 31 are connected via the communication hole 35. Further, since the connection hole 40 is closed by the valve body 41, the front and rear space portions 46 and 47 of the booster 32 have the same negative pressure, and no pressure difference occurs.

Accordingly, the urging force of the spring 49 causes the piston 45 and the piston lot 50 to move to the rear space 4
Move to side 7. Therefore, the brake piston 27 of the master cylinder 26 moves to the second hydraulic chamber 29 side,
The hydraulic oil 58 in the first hydraulic chamber 28 is not pressurized. As a result, the brake device of the vehicle 25 does not operate.

On the other hand, as shown in FIG. 1, when the brake pedal 54 is depressed, the hydraulic oil 58 in the hydraulic pipe 55 and the branch pipe 56 is pressurized. Then, the master cylinder 26
The brake piston 27 moves to the first hydraulic chamber 28 side, and the hydraulic oil 58 in the first hydraulic chamber 28 is pressurized.

When the hydraulic oil 58 in the branch pipe 56 is pressurized, the valve member 34 rises and pushes the valve body 41 upward. Therefore, the communication hole 35 is closed by the valve body 41, and the first and second partitioned chambers 36 and 37 are partitioned. Further, since the valve body 41 is pushed upward, the connection hole 40 is opened and the first compartment 36 is communicated with the outside.
Therefore, the first compartment 36 and the rear space 47 are at atmospheric pressure.

Then, the rear side space 47 becomes atmospheric pressure and the front side space 46 becomes negative pressure, and a pressure difference is generated. Therefore, the piston 45 moves toward the front space portion 46 side against the biasing force of the spring 49. This piston 4
5, the brake piston 27 of the master cylinder 26 is further moved through the piston rod 50 to move the first hydraulic chamber 2
Move to side 8. Therefore, the hydraulic oil 58 in the first hydraulic chamber 28
Is further pressurized, the brake device is further operated, and the rotation of the wheels 30 is decelerated or stopped.

Next, the operation of the vane type vacuum pump protection device constructed as described above will be described with reference to the flow chart shown in FIG. The controller 62 determines whether the engine speed of the engine 15 is 2000 rpm or more based on the detection signal from the rotation speed sensor 63 (step 1). Engine speed is 2000 rp
If it is less than m, the controller 62 uses 2000 rpm
Wait for the above to happen. And the controller 62
Determines that the engine speed has reached 2000 rpm or more based on the detection signal from the rotation speed sensor 63, then determines whether the brake pedal 54 is depressed based on the detection signal from the brake pedal sensor 64. Yes (step 2).

When it is detected that the brake pedal 54 is depressed based on the detection signal from the brake pedal sensor 64, the controller 62 causes the step 1
And the above process is repeated again.

When the controller 62 determines that the brake pedal 54 is not depressed based on the detection signal from the brake pedal sensor 64, the controller 62 operates the switching valve 60 to connect the connecting pipe 2 to the pipe 61. It is connected to the outside through (step 3). At this time, the timer circuit 65 counts the open time.

The controller 62 is the switching valve 6
When 0 is operated, it is determined whether the brake pedal 54 is depressed based on the detection signal from the brake pedal sensor 64 (step 4). Then, when the brake pedal 54 is not depressed, the controller 62 continuously operates the switching valve 60. After that, the controller 62 determines based on the count of the timer circuit 65 whether or not it is equal to or longer than the opening time (3 seconds) during which the switching valve 60 is operated (step 5). When the controller 62 determines that the operating time of the switching valve 60 is not equal to or longer than the opening time, the process proceeds to step 3 and the controller 62 keeps the switching valve 60 in an operating state.

When the operating time of the switching valve 60 is equal to or longer than the opening time, the controller 62 stops the operation of the switching valve 60 and shuts off the connection pipe 2 so as not to connect it to the outside. (Step 6). Then, in step 4, if the brake pedal 54 is depressed while the switching valve 60 is operating, the controller 62 causes the step 6
Then, the operation of the switching valve 60 is stopped and the connection pipe 2 is shut off so as not to be connected to the outside. At this time, the timer circuit 65 counts the time when the switching valve 60 is stopped.

After that, the controller 62 controls the timer circuit 6
It is determined whether or not the time counted by 5 and the blocking time (5 minutes) match or exceed (step 7). When the time counted by the timer circuit 65 does not match or exceed the blocking time, the controller 62 waits until it matches or exceeds the blocking time.

When the controller 62 determines that the time counted by the timer circuit 65 matches or exceeds the blocking time, it determines whether the engine 15 has stopped (step 8). When the engine 15 is stopped, the controller 62 ends the above process. Then, when the engine 15 is operating, the controller 62 proceeds to step 1 and performs the same processing as above.

Therefore, when the switching valve 60 is operated by the controller 62 and the connection pipe 2 is connected to the outside through the pipe 61, the inside of the connection pipe 2 has a negative pressure, and therefore air is in the connection pipe 2. Is sucked into.

The air sucked into the connecting pipe 2 is sucked by the vacuum pump 3. This air is compressed by the vacuum pump 3 and discharged from the discharge port 13 into the engine 15. Also, the switching valve 60
Since the operating time is short, the amount of air sucked into the connection pipe 2 is very small. Although the amount of air sucked into the connection pipe 2 is very small, if the vacuum pump 3 compresses the air, a slight flow of the air discharged from the discharge port 13 into the engine 15 is formed. Therefore, the lubricating oil 22 that lubricates the engine 15 into the space 10 through the discharge port 13
Can be prevented from being inhaled.

Therefore, the lubricating oil 22 can be prevented from being compressed in the space portion 10 of the vacuum pump 3. As a result, the blade 9 of the vacuum pump 3
Can be prevented from being worn, the suction / discharge efficiency of the vacuum pump 3 can be improved, and the life can be extended. Moreover, since the lubricating oil 22 can be prevented from being sucked into the space 10, it is not necessary to reduce the volume of the space 10. As a result, the number of blades 9 can be reduced,
It is possible to prevent an increase in the number of parts and facilitate assembly work.

Further, in the present embodiment, when the engine speed of the engine 15 is 2000 rpm or more and the lubricating amount of the lubricating oil 22 is large, the vacuum pump 3 easily sucks the lubricating oil 22, so only at that time. Three
A small amount of air is sucked in to prevent the lubricating oil 22 from being sucked. As a result, the opening / closing operation of the switching valve 60 can be suppressed as much as possible and the amount of air discharged from the discharge port 13 by the vacuum pump 3 can be reduced, so that the increase of blow-by gas can be suppressed as much as possible. Also, since the amount of air sucked into the connection pipe 2 is very small, the negative pressure of the brake booster 1 is reduced, and the assisting force of the brake booster 1 when the brake pedal 54 is depressed is prevented from being significantly reduced. be able to.

Further, if the brake pedal 54 is depressed while the switching valve 60 is operating, the operation of the switching valve 60 is immediately stopped. As a result, when the brake pedal 54 is depressed,
It is possible to suppress a decrease in negative pressure, obtain a sufficient assisting force by the brake booster 1, and decelerate or stop the vehicle 25.

In this embodiment, the switching valve 60 is opened when the rotation speed of the engine 15 is 2000 rpm or more and the brake pedal 54 is not depressed. In addition to this, the switching valve 60 is opened only when the brake pedal 54 is not depressed as necessary. When the brake pedal 54 is depressed, the switching valve 6
It is also possible to configure 0 to be closed.

Further, in the present embodiment, although the engine 15 determines the high rotation state by the rotation speed sensor 63, the oil temperature of the lubricating oil 22 is measured by the oil temperature sensor, and the controller 62 detects the oil temperature based on the detection signal. It is also possible to configure the switching valve 60 to be controlled to open and close.

Since the opening / closing control of the switching valve 60 is performed based on the timer circuit 65, the opening / closing control of the switching valve 60 can be easily performed.

Further, the opening time of the switching valve 60 is set to 3 seconds and the closing time is set to 5 minutes, but this time setting can be arbitrarily changed as required. Next, another example of the present invention will be described. The same members as those in the above-described embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 4, a switching valve 70 as a switching valve is connected to the brake pedal 54. At this time, the vacuum pump 3 is connected to the rear space 47 of the booster 32 via the switching valve 70 and directly to the front space 46. or,
The vacuum pump 3 is connected via a switching valve 70 to a throttle valve 71 that is open to the atmosphere. The throttle valve 71 adjusts the amount of air sucked by the vacuum pump 3, but the suction amount is extremely small.

When the brake pedal 54 is depressed, the switching valve 70 operates and the vacuum pump 3 is connected only to the front space 46. The rear space 47 of the booster 32 is connected to the outside and is open to the atmosphere.

When the brake pedal 54 is not depressed, the vacuum pump 3 is connected to the front and rear space portions 46 and 47 of the booster 43 and the throttle valve 71. Therefore, the vacuum pump 3 sucks a very small amount of air through the throttle valve 71 and also sucks air in the front and rear space portions 46, 47. Therefore, the front and rear spaces 46 and 47 have the same negative pressure, so that the piston 45 is urged by the urging force of the spring 49.
Moves to the rear space 47. Therefore, the braking operation is not performed.

Further, since the vacuum pump 3 sucks a very small amount of air through the throttle valve 71, this air is discharged from the discharge port 1.
3 is discharged into the engine 15. As a result, it is possible to prevent the lubricating oil 22 from being sucked.

When the brake pedal 54 is depressed, the switching valve 70 operates. Therefore, the vacuum pump 3 is connected only to the front space 46, and the rear space 47 is open to the atmosphere. As a result, the piston 45 moves to the front space 46 against the urging force of the spring 49, and brakes.

Also in the structure of this another example, the lubricating oil 22 can be prevented from being sucked by the vacuum pump 3 from the discharge port 13. Next, technical ideas other than the claims, which are understood from the above-described embodiments, will be described below along with their effects.

(1) A timer circuit according to claim 2 or 3, wherein the switching valve is provided with a short opening time such that the negative pressure of the booster does not decrease and a closing time until the pressures in the front and rear spaces are stabilized. The switching valve control means controls the switching valve based on the opening time and the closing time set in the timer circuit.

Since the switching valve controls the switching valve based on the opening time and closing time set in the timer circuit, the switching valve can be easily controlled to open and close.

[0073]

As described above in detail, according to the first aspect of the present invention, the vane vacuum pump can prevent the lubricating oil from being sucked through the discharge port, so that the wear of the blade can be prevented. As a result, the suction / discharge efficiency can be improved and the life of the vane type vacuum pump can be extended. Moreover, since it is not necessary to increase the number of blades, it is possible to suppress an increase in the number of parts of the vane type vacuum pump and facilitate the assembling work. Further, since the amount of air sucked in is very small, the amount of air released into the diesel engine is also very small, and the generation of blow-by gas can be suppressed.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, when the brake pedal is depressed, the opening / closing control of the switching valve is stopped, which adversely affects the operation of the booster. You can choose not to give.

According to the invention described in claim 3, in addition to the effect of the invention described in claim 2, when the rotation speed of the diesel engine is a predetermined rotation speed or more and the brake pedal is not depressed, By letting the vane vacuum pump suck a small amount of air, it is possible to prevent the vane vacuum pump from sucking the lubricating oil. At this time, although the amount of lubrication oil is large, suction of the lubrication oil can be reliably prevented. Moreover, since the opening / closing control of the switching valve is reduced, the amount of air sucked is small and the generation of blow-by gas can be suppressed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram in which a brake system of a diesel engine is provided with a vacuum pump protection device.

FIG. 2 is an explanatory diagram in which a brake system of a diesel engine is provided with a vacuum pump protection device.

FIG. 3 is a flow chart for explaining the operation of the vacuum pump protection device.

FIG. 4 is a configuration diagram showing a configuration of a vacuum pump protection device as another example.

FIG. 5 is a perspective view in which a vacuum pump is connected to a brake booster.

FIG. 6 is a partial cross-sectional view showing a simplified internal configuration of a vacuum pump.

FIG. 7 is a partial sectional view of a vacuum pump attached to a diesel engine.

[Explanation of symbols]

3 ... Vane type vacuum pump, 13 ... Discharge port, 15 ...
Diesel engine, 31 ... switching valve, 32 ... booster,
46 ... Front side space part, 47 ... Rear side space part, 49 ...
Spring 54, brake pedal 60, switching valve 62, controller as switching valve control means 63, rotation speed sensor as engine speed detection means 64, brake pedal sensor as brake detection means 70, switching Switching valve as a valve,
71 ... Throttle valve

Claims (3)

[Claims] 1. A booster in which a spring for moving a piston, which is divided into a front space portion and a rear space portion, to a rear space portion is arranged in the front space portion, and a booster arranged in a diesel engine. Of the vane-type vacuum pump that sucks the air in the front or front and rear side spaces and discharges the air from the discharge port to make the front or front and rear side spaces a negative pressure, and the brake pedal When the rear side space is opened to the atmosphere based on the depression, and the switching valve that makes the front and rear spaces the same negative pressure by the vane vacuum pump when the brake pedal is released, and the brake pedal is not depressed. , A throttling device that connects a vane vacuum pump to the atmosphere through a switching valve to suck in a small amount of air Protective device for vane vacuum pump for diesel engine equipped with valve. 2. A booster in which a spring for moving a piston that divides a front space portion and a rear space portion to a rear space portion is arranged in the front space portion, and a booster arranged in a diesel engine. Of the vane-type vacuum pump that sucks the air in the front or front and rear side spaces and discharges the air from the discharge port to make the front or front and rear side spaces a negative pressure, and the brake pedal The rear side space is connected to the atmosphere based on the depression, and the switching valve that depresses the accelerator pedal to release the front or front and rear side spaces to a negative pressure by the suction of the vane vacuum pump, and the brake pedal is depressed. The brake detection means to detect the When the brake pedal is not stepped on based on the switching valve to be sucked and the detection signal from the brake detection means, the switching valve is controlled to be opened and closed to connect the vane vacuum pump to the atmosphere to suck a small amount of air. A vane vacuum pump protection device for a diesel engine, comprising a switching valve control means. 3. The engine speed detecting means for detecting the engine speed of a diesel engine according to claim 2, wherein the engine speed is equal to or higher than a predetermined speed based on a detection signal from the engine speed detecting means. Next to
Moreover, when the brake pedal is not stepped on based on the detection signal from the brake detection means, the switching valve control means controls the opening and closing of the switching valve to connect the vane vacuum pump to the atmosphere and suck a small amount of air. Protective device for vane vacuum pump for diesel engine.