JPS6134923Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a negative pressure supply device for vehicles.
For example, it is effective for use as a negative pressure supply device that supplies negative pressure to the negative pressure chamber of a negative pressure booster brake.

[Conventional technology]

For example, as a conventional negative pressure supply device,
There is one described in the specification of No. 58907 (Utility Model Application Publication No. 50-155610). This negative pressure supply device has a decompression chamber formed only on one side of the diaphragm, and a suction chamber and a discharge chamber that communicate with this depressurization chamber via a suction check valve and a discharge check valve. The sides are exposed to the atmosphere. The suction chamber communicates with a negative pressure chamber of the brake device, and the discharge chamber communicates with an intake manifold of the engine or is open to the atmosphere.

[Problem that the invention attempts to solve]

However, with the above-mentioned device, one side of the diaphragm is exposed to the atmosphere, so if the diaphragm breaks, the atmosphere will flow into the decompression chamber formed on the other side of the diaphragm. Then, if the discharge chamber is in communication with the engine's intake manifold, the intake check valve is closed, but since the discharge chamber is always under negative pressure, the atmospheric air flowing into the decompression chamber is used for discharge. Push open the check valve and let it flow into the engine's intake manifold. As a result, the ratio of the intake air amount of the engine changes, causing a problem in that the combustion state of the engine changes.

Furthermore, even if the discharge chamber is open to the atmosphere, the suction check valve is closed, so the negative pressure supply path that leads negative pressure to the negative pressure chamber of the brake booster is cut off. As a result, there is a problem in that the negative pressure in the negative pressure chamber of the brake booster decreases every time the brake is operated, and the driver feels uncomfortable when the brake pedal is depressed.

[Cause analysis of the problem]

The problem mentioned above is that the suction chamber, discharge chamber, and decompression chamber are formed only on one side of the diaphragm, and the other side is open to the atmosphere, so if the diaphragm breaks, the atmosphere on the other side will pass through the broken part. This is due to a technical reason that the gas flows into the decompression chamber, suction chamber, and discharge chamber.

[Technical issues of invention]

The technical problem of the present invention is to prevent atmospheric air from flowing into the chambers where negative pressure is applied (in the conventional example, the suction chamber, discharge chamber, and decompression chamber) even if the diaphragm is damaged.

[Means for solving problems]

In order to achieve the above technical problem, the present invention takes the following measures. That is, in a vehicle equipped with a negative pressure actuator, a reciprocating member reciprocates within a housing, a pump chamber defined on one side of the reciprocating member, and a pump chamber defined on the other side of the reciprocating member. a first backflow prevention valve disposed in a passage communicating the pump chamber and the negative pressure actuator; and a second backflow prevention valve disposed in the passage communicating the pump chamber and the crank chamber. a prevention valve, and a third check valve disposed in a passage communicating between the crank chamber and a negative pressure outlet port of the engine, and the first to third check valves are connected from the negative pressure actuator side. The negative pressure supply device for a vehicle is characterized in that fluid is passed only in the direction toward the negative pressure extraction port.

[Operation] If the reciprocating member is damaged and the pump chamber and crank chamber communicate with each other, the negative pressure from the negative pressure outlet port of the engine is introduced into the crank chamber via the third check valve. Only the negative pressure in the crank chamber is introduced into the pump chamber through the damaged part of the reciprocating member, and atmospheric air does not flow into the pump chamber.

[Effect of idea]

In this invention, a pump chamber is provided on one side of the reciprocating member.
A crank chamber is formed on the other side, and negative pressure from the engine's negative pressure outlet port is introduced into the crank chamber, so even if the negative pressure in the pump chamber increases due to the operation of the reciprocating member, There is almost no differential pressure between the opposite sides of the reciprocating member. Therefore, the drive load due to the differential pressure when the reciprocating member reciprocates is small, and therefore the drive power can be significantly reduced, which is a unique effect.

(Example) An example of the present invention shown in the drawings will be described below.

In FIG. 1, 10 is an engine, 11 is an intake pipe, 12 is an exhaust pipe, 13 is a throttle valve, 1
4 is a negative pressure outlet port provided downstream of the throttle valve 13. 20 is the brake pedal, 3
0 is a master back that serves as a negative pressure actuator for reducing the pressing force on the brake pedal 20; 40;
1 is a master cylinder that generates hydraulic pressure when the brake pedal 20 is operated, 50a and 50b are front brakes and rear brakes that operate in response to hydraulic pressure from the master cylinder 40, and 100 is a diaphragm vacuum that supplies negative pressure to the master back 30. pump, 60 is an electric motor that drives this pump 100, 70 is a relay having a relay coil 71 and relay contacts 72, 80 is an on-vehicle battery,
90 is a key switch.

Next, the master back 30, the master cylinder 40
and vacuum pump 100 will be explained in detail.

In the master bag 30, a diaphragm 32 to which a plate 31 is attached is connected to a housing 33 and a cover 34.
First and second pressure chambers 35a and 35b are formed on both sides of the diaphragm 32. The plate 31 has a cylinder 31a and a rod chamber 31b, and is also formed with first and second communicating holes 31c, 31d and a sliding hole 31e. Rod 36 interlocked with brake pedal 20
One end of the rod 3 is inserted into the sliding hole 31e.
The valve member 37 has a first valve body 37a that opens and closes the first communication hole 31c and a second valve body 37b that opens and closes the second communication hole 31d.
is slidably mounted. The plate 31 and the diaphragm 32 are connected to the first spring 38a.
The valve member 37 is biased to the right in the figure by the second spring 38b, and the valve member 37 is biased to the left in the figure by the second spring 38b. 39a and 39b are seal members.

The master cylinder 40 includes first and second pistons 42 and 43 in a bottomed cylindrical housing 41.
are inserted, and two seal members 42a, 42b, 43a, 43b are inserted into each piston 42, 43.
is installed. A first spring 45a is installed in a first piston chamber 44a formed between the first piston 42 and the bottom of the housing 41, and this chamber 44a is located within a first reservoir 46a and a front brake 50a. will be contacted. Further, a second spring 45b is installed in a second piston chamber 44b formed between both pistons 42 and 43, and this chamber 44b is connected to a second reservoir 46b and a rear brake 50b.
will be contacted.

In the vacuum pump 100, the lower end of a connecting rod 104 and a bearing 106 are inserted into one end of a crankshaft 102 which is rotated by an electric motor 60, and are fixed with a hexagonal nut 108. The upper part of the cooking rod 104 has a flange part 1.
04a and a space 104b is formed so that a non-return valve (described later) can freely move, and a passage 104c that communicates the space 104b with the crank chamber 110 is formed. A diaphragm 112 made of a rubber material is held at its outer periphery by the lower housing 14 and the upper housing 116, and is also attached to the flange 104 of the connecting rod 104.
The center portion is held between the plate 118 and the plate 118. The diaphragm 112 and the lower housing 114 form the aforementioned crank chamber 110, and the diaphragm 112 and the upper housing 116 form a pump chamber 120. A cover 124 integrally formed with a pipe 122 is attached above the upper housing 116 to cover the chamber 12.
b is formed, and this cover 124 has a chamber 126
A pressure switch 128 is built in to open and close the circuit between the coil 71 of the relay 70 and the battery 80 by sensing the pressure. Lower housing 114
Two openings are formed at the bottom of the opening, an electric motor 60 is airtightly attached to one opening, and a plate 130 is airtightly attached to the other opening. It is covered with a molded cover 134. The pump chamber 120 described above can communicate with the first pressure chamber 35a of the master bag 30 via the first communication hole 136 formed in the housing 116 and the chamber 126, and can communicate with the first pressure chamber 35a of the master bag 30 through a second communication hole 136 formed in the plate 118. It is possible to communicate with the negative pressure extraction port 14 through the hole 138, the space 104b, the passage 104c, the crank chamber 110, and a third communication hole 140 formed in the plate 130. The upper housing 116 has a first communication hole 13.
The first check valve 142 opens and closes the second communication hole 138 in the plate 118, and the second check valve 142 opens and closes the second communication hole 138 in the plate 118.
A third non-return valve 144 is provided on the plate 130.
The third check valve 14 opens and closes the communication hole 140 of the
6 are attached respectively. These check valves 142, 144, and 146 are all assembled so as to allow fluid to flow only from the first pressure chamber 35a of the master bag 30 toward the negative pressure outlet port 14. The connecting rod 104, housings 114, 116, plates 118, 130, and covers 124, 134 are made of aluminum, for example.

Next, the operation will be explained. When the key switch 90 is turned on and the engine 10 is rotating,
When the pressure in the chamber 126 becomes negative pressure (negative pressure close to atmospheric pressure) smaller than the set negative pressure or becomes atmospheric pressure, the pressure switch 128 is turned on, current flows through the relay coil 71, the relay contact 72 is turned on, and the electric motor is turned on. 6
0, and the vacuum pump 100 is driven. The rotation of the electric motor 60 is caused by the vacuum pump 1.
This is converted into a reciprocating motion by the crankshaft 102 and connecting rod 104 of 00, and is transmitted to the diaphragm 112. When the diaphragm 112 is pushed upward in the figure, the first check valve 14
2 closes and the second check valve 144 opens, the air in the pump chamber 120 is discharged to the crank chamber 110 side, and when the diaphragm 112 is pulled downward, the first check valve 142 opens and the second check valve 144 opens. The check valve 144 closes, and the air inside the master bag 30 is sucked into the pump chamber 120. At this time, the third check valve 146 operates according to the pressure difference between the negative pressure outlet port 14 and the crank chamber 110. Note that when the pressure in the chamber 126 becomes a negative pressure greater than the set negative pressure, the pressure switch 128 is turned off and the electric motor 6 is turned off.
Although the power consumption is reduced by stopping the power supply to the master bag 30, in any case, the negative pressure necessary for its proper operation is maintained within the master bag 30.

When the brake pedal 20 is not depressed, both pressure chambers 35a, 3 of the master bag 30
5b communicate with each other through both communication holes 31c and 31d, the diaphragm 32 and the like are held in the illustrated position by the first spring 38a. on the other hand,
When you step on the brake pedal 20, the rod 36 first
Since the valve member 37 moves to the left in the figure, the first
The valve body 37a closes the first communication hole 31c and isolates both pressure chambers 35a and 35b, and the second valve body 37b
is located on the left side of the second communication hole 31d in the figure and opens the second pressure chamber 35b to the atmosphere. Therefore, the plate 31 and the diaphragm 32 are moved to the left in the figure by the force due to the pressure difference between the pressure chambers 35a, 35b and the pedal depression force. This movement of the plate 31 causes the two pistons 42 and 43 of the master cylinder 40 to operate, and each piston chamber 44
The hydraulic pressure of the brake oil in a and 44b is increased,
The high oil pressure is sent to each brake 50a, 50b to perform braking.

By the way, abnormally high pressure (positive pressure) may be generated in the intake pipe 11 due to the backfire of the engine 10, and in that case, the third check valve 14
6 is closed, high pressure does not act on the crank chamber 110, and damage to the diaphragm 112 is prevented. Further, the third check valve 146 also serves to prevent fuel vapor from entering the crank chamber 110.

Furthermore, even if the diaphragm 112 is damaged for some reason, each check valve 142, 14
4 and 146 as described above, the negative pressure of the negative pressure outlet port 14 will surely act on the master bag 30 and the function of the master bag 30 will be maintained, and since the crank chamber 110 does not communicate with the atmosphere,
There is no possibility that atmospheric air will flow into the intake pipe 11 through the negative pressure outlet port 14 and cause engine malfunction.

Note that the pressure switch 128 in the above embodiment
may be installed facing the first pressure chamber 35a of the master bag 30, or may be installed in a passage connecting the pressure chamber 35a and the chamber 126 of the vacuum pump 100. In addition, each check valve 14
2, 144, 146 may be replaced with a so-called reed valve made of a thin steel plate, for example. Furthermore, a negative pressure tank may be provided between the vacuum pump 100 and the master bag 30. Furthermore, instead of the master bag 30, a brake device using a so-called booster that operates to pull the pistons 42, 43 of the master cylinder 40 during braking may also be used.
The present invention is applicable. The structure of the booster is similar to the master bag 30 and is well known, so a description thereof will be omitted.

FIG. 2 shows another example of the vacuum pump, which differs from the previous embodiment in that a pump 150 is used instead of the diaphragm 112.
A piston cylinder 152 is used to maintain airtightness, and in order to prevent sliding wear and reduce frictional force, the piston cylinder 152 is made of tetrafluoroethylene-based material that is resistant to sliding wear and has low frictional force. A formed cylinder liner 154 is provided. In addition,
Parts that are the same as or equivalent to those in the previous embodiment are given the same reference numerals.

The present invention is applicable not only to master bags and boosters, but also as a negative pressure supply device for negative pressure actuators used in exhaust gas purification devices and air conditioning devices, for example.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the device of the present invention, and FIG. 2 is a sectional view showing another example of the vacuum pump. 10...Engine, 14...Negative pressure extraction port,
30...Master back forming a negative pressure actuator,
100... Vacuum pump, 110... Crank chamber, 112... Diaphragm forming a reciprocating member, 114, 116... Housing, 120...
Pump chamber, 142...first check valve, 144
. . . second check valve, 146 . . . third check valve, 150 …… piston forming a reciprocating member.

Claims (1)

[Scope of utility model registration claims] (1) In a vehicle equipped with a negative pressure actuator,
a reciprocating member that reciprocates within a housing; a pump chamber defined on one side of the reciprocating member; a crank chamber defined on the other side of the reciprocating member; A first disposed in a passage communicating with the negative pressure actuator.
a second check valve disposed in a passage communicating the pump chamber and the crank chamber; and a second check valve disposed in the passage communicating the crank chamber and the negative pressure outlet port of the engine. 3, wherein the first to third check valves allow fluid to pass only in a direction from the negative pressure actuator side to the negative pressure outlet port side. (2) The negative pressure supply device for a vehicle according to claim 1, wherein the reciprocating member is a diaphragm. (3) The negative pressure supply device for a vehicle according to claim 1, wherein the reciprocating member is a piston. (4) Negative pressure supply for a vehicle according to any one of claims 1 to 3, characterized in that the third check valve is integrally attached to the vacuum pump. Device.