JP2982334B2 - Vacuum pump operation detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the operation of a vacuum pump.

[0002]

2. Description of the Related Art In some cases, a vacuum pump used for a brake booster is directly connected to an alternator rotated by a vehicle engine. In such a vacuum pump, the operation of the vacuum pump is stopped due to an abnormality in the drive transmission system of the alternator. Sometimes. In this case, conventionally, a decrease in the negative pressure of the vacuum tank connected to the vacuum pump is detected to indirectly confirm and warn the operation state of the vacuum pump.

That is, in FIG. 8 , P is a vacuum pump, and a vacuum tank 61 is connected to a suction port 11 of the pump P via a check valve 65. The booster 62 is connected to the vacuum tank 61 via a check valve 66. The vacuum tank 61 is provided with a pressure switch 63, and an alarm output of the pressure switch 63 is input to an alarm device 64.

In such an operation detection, the vacuum pump P
Is stopped and the alarm is output only when the negative pressure of the vacuum tank 61 is reduced, so that when the alarm is issued, there is a problem that the brake boosting effect is not exerted.

Therefore, for example, Japanese Utility Model Publication No. 64-7221 proposes a device for connecting a pressure introduction pipe for a pressure switch to a suction port and directly detecting a negative pressure in this portion.

[0006]

However, since the pressure fluctuation of the vacuum tank connected to the suction port directly spreads to the suction port, the above-mentioned proposed device temporarily reduces the negative pressure in the vacuum tank when the booster is activated. False detection may occur due to the effect of the drop. To avoid this, it is necessary to add a delay time to the operation of the pressure switch, but this reduces the response of detection.

Further, in the above proposed apparatus, when the vacuum pump is stopped, the pressure in the pump rapidly rises to the atmospheric pressure, so that the lubricating oil may flow backward toward the pressure switch.

Further, if the pressure introducing pipe leading to the pressure switch is disconnected, there is a problem that the pump function is impaired.

An object of the present invention is to provide a vacuum pump operation detecting device which solves the above problem and has good responsiveness and does not cause a risk of lubricating oil backflow or loss of pump function.

[0010]

To explain the structure of the present invention, a rotor 2 which rotates in an eccentric state is provided in a housing 1 having a circular inner periphery, and a space inside the housing 1 on the outer periphery of the rotor 2 is made to have a volume. Multiple pump chambers P0, P that shrink after expansion
1, a suction port 11 communicating with the vacuum tank is opened in the expansion pump chamber P2, which is formed into partitions P1 , P3 , and P4 , and gradually expands in volume, thereby sucking gas into the pump chamber P2 and gradually reducing the volume. in the vacuum pump P for compressing eject intake air from the shrink pump chamber P 4 to the discharge port 12, away from the inlet port 11 installed position,
The position (A) where the pump chambers P0, P1 , P2 start expanding.
Point) close to the vane interval from the suction port 11
The outer periphery of the rotor 2 is
Provided with a pipe member 3 which opens therethrough into the housing 1 wall within angular position closest to the ring first wall into the pump chamber P 0, aperture small diameter portion of the inner circumference to the pipe member 3 A part 31 is formed, and one end of a hose 4 is connected to an outer opening of the housing 1 of the pipe member 3.
Is connected to a connection port 51 of a pressure switch 5 provided at a position above the vacuum pump P.

In the apparatus having the above structure, the pipe member 3
Are located in the pump chambers P0, P
1, P2 is Ri Ah provided in allowed opening the housing 1 wall position (A point) closer to initiate expansion, opening of the pipe member 3
The position is further from the suction port 11 by the vane interval
The outer periphery of the rotor 2 is a housing
Because it is within the angular position closest to one wall, pie
The pump member 3 always sucks directly regardless of the rotational position of the rotor 2.
There is no communication with the port 11. Therefore, the vacuum
Pump operation can be detected regardless of the pressure inside the pump.
You. Therefore, it is hardly affected by the pressure fluctuation of the vacuum tank,
Therefore, even if the delay time is not given to the pressure switch 5, no malfunction occurs.

Further, since the throttle member 31 is partially formed in the pipe member 3, the suction negative pressure of the pump chamber P1 does not decrease even if the hose 4 comes off for some reason. The problem that the operation of the pump is impaired does not occur.

The formation of the throttle 31 and the provision of the pressure switch 5 above the vacuum pump P prevent the lubricating oil from flowing back to the pressure switch 5 when the pump is stopped.

[0014]

FIG. 7 shows a main structure of a brake booster using a vacuum pump having an operation detecting device according to the present invention.

The difference from the conventional device is that a pressure switch 5 connected to the vacuum pump P by a hose 4 is provided, and the alarm output of the pressure switch 5 is output together with the alarm output of the existing pressure switch 63 of the vacuum tank 61 and a buzzer. The information is input to an alarm device 64 having an indicator light and the like.

The vacuum pump P is, for example, a vane pump as shown in FIG. 1, and is integrally connected to a rotating shaft 21 of an alternator (not shown) and rotates eccentrically in a housing 1 having a circular inner periphery (in the figure). Arrow direction) circular rotor 2
Is provided. The rotor 2 has a plurality of outer circumferences (this embodiment
4) The vanes 22 are protruded at regular intervals at positions, and the tips of the vanes 22 abut against the inner periphery of the housing 1, and the volume gradually increases between the vanes 22 with the rotation of the rotor 2. A plurality of pump chambers P0 to be reduced ,
P1, P2, P3 , and P4 are sectioned.

A suction port 11 is formed on the wall of the housing 1 by communicating with an expansion pump chamber P2 whose capacity gradually increases. The suction port 11 is connected to the vacuum tank 61 through the check valve 65 described above.
In communication with The discharge port 12 in the housing 1 wall gradually brought communicated with the contraction pump chamber P 4 in which the volume is reduced
Are formed, and the discharge port 12 is open to the atmosphere. Thus, the air in the vacuum tank 61 is
, And is compressed and discharged to the discharge port 12 when the pump chamber P2 reaches the position of the pump chamber P4 via the position of the pump chamber P3. This allows
The evacuation of the vacuum tank 61 is performed.

[0018] Now, the pump chamber P 0 that initiated the volumetric expansion are pipe member 3 is driving fixed and brought through the housing first wall to the vertical direction. For more details, see the pipe section
The material 3 is provided on the wall of the housing 1 between the points C and G in the figure.
Have been. The point C is located between the intake port 11 and the vane 22.
At an angular position separated by the installation interval (90 ° in this embodiment)
In addition, at point G, the outer periphery of the rotor 2 is the inner peripheral wall of the housing 1.
At the closest angle position to In addition, the pipe member 3 is formed at the base end located outside the housing 1 and has a reduced inner diameter as shown in FIGS.

Above the vacuum pump P, a known pressure switch 5 is fixed at an appropriate position on the vehicle body by a bracket 52. A connection port 51 of the pressure switch 5 and a base end of the pipe member 3 are connected to a hose 4 by a hose 4. It is connected with.
The pressure switch 5 closes the contact when the degree of vacuum falls below a certain level (point B in FIG. 4) and issues an alarm output.

In the operation detecting device having the above structure, when the rotor 2 starts rotating, the internal pressure of the pump chamber P1 immediately decreases, the degree of vacuum increases (solid line in FIG. 4), and the pressure switch 5
Opens the contacts. Rotor 2 keeps rotating and vane pump P
Since the inside of the pump chamber P1 is maintained at a sufficient negative pressure as long as is normally operated, no alarm output is issued from the pressure switch 5.

When the rotation of the rotor 2 stops due to an abnormality in the drive transmission system of the alternator or the like, the internal pressure of the pump chamber P1 rapidly recovers to the atmospheric pressure, the degree of vacuum drops below the point B, and the contact point of the pressure switch 5 changes. Closed and an alarm output is issued.

As described above, since the negative pressure in the pump chamber is directly detected, a malfunction of the pump can be promptly detected. Incidentally, the broken line in FIG. 4 indicates the pressure change in the vacuum tank 61, and the rise and fall of the degree of vacuum with respect to the start / stop of the pump has a large time delay.

In this embodiment, the pipe member 3 for detecting pressure is used.
Is provided near the position where the pump chamber P1 starts to expand, away from the suction port 11, and is not affected by a temporary decrease in the degree of vacuum in the vacuum tank 61 when the brake booster is activated.
Therefore, it is not necessary to add a delay time to the pressure detection, and the pump operation can be detected with good responsiveness. Also,
The area between the points C and G in the figure where the
The first pump chamber P0) has a negative pressure during the operation of the pump.
When the pump stops, the discharge port 1
Negative pressure drops fastest when air flows in from 2
(Shaded area in FIG. 5). Also, this area is the suction port
Direct suction port because it is more than vane interval from 11
No communication with the pump 11 and the earliest
The negative pressure rises (shaded area in FIG. 6). And this
By providing the pipe member 3 in the area, when the pump is stopped
Negative pressure drop and negative pressure rise at pump startup with pressure switch
Faster detection enables quicker pump operation detection
You.

Further, since the throttle portion 31 is formed in a part of the pipe member 3, even if the hose 4 comes off, the suction negative pressure of the pump chamber P1 does not decrease and the pump operation is not impaired. .

Further, the above-mentioned constricted portion 31 is formed, and
By providing the pressure switch 5 above the vacuum pump P, lubricating oil does not flow back to the pressure switch 5 when the pump is stopped.

Since the connection between the pressure switch and the pipe member is made of a hose, the flexibility of piping is high and the connection is easy.

In the above embodiment, the vacuum pump does not need to be provided with an alternator, and the pressure switch can be fixed by another method such as caulking. Instead of driving and fixing the pipe member, a structure in which the pipe member is fixed to the housing wall with screws and sealed with packing may be used.

It is a matter of course that an alarm detecting device dedicated to the operation detecting device may be provided.

[0029]

[0030]

[0031]

According to the operation detecting device for a vacuum pump of the present invention, it is possible to quickly and surely detect a malfunction of the pump, to lose the pump function due to the disconnection of the detecting hose, or to prevent the pressure switch from being operated. There is no problem such as backflow of the pump lubricating oil.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vacuum pump incorporating an operation detecting device according to the present invention.

FIG. 2 is a longitudinal sectional view of a pipe member.

FIG. 3 is a front view of a base side of the pipe member.

FIG. 4 is a diagram showing a change over time of a pump chamber pressure of a vacuum pump.

FIG. 5 is a diagram showing a negative pressure drop time at each angular position.
You.

FIG. 6 is a diagram showing a negative pressure rise time at each angular position.
You.

FIG. 7 is a brake booster incorporating the operation detection device of the present invention .
FIG.

FIG. 8 is a configuration diagram of a conventional brake booster.

[Explanation of symbols]

Reference Signs List 1 housing 11 suction port 12 discharge port 2 rotor 3 pipe member 4 hose 5 pressure switch 51 connection port P vacuum pump P0, P1, P2, P3 , P4 pump room

────────────────────────────────────────────────── ─── Continuing on the front page (72) Noboru Ikoma, 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Corporation (72) Inventor Hiroki Yoshimura 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nihon Denso Co., Ltd. (56) References JP-A-59-208192 (JP, A) JP-A-59-42423 (JP, A) JP-A-57-8428 (JP, A) J. 55-11466 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) F04C 23/00-29/10 331 F04C 18/30-18/352 F04B 37/14 G01L 19 / 00 G01L 21/00

Claims (1)

(57) [Claims] A plurality of rotors, which rotate in an eccentric state, are provided in a housing space having a circular inner periphery, and a plurality of vanes provided at equal intervals on the outer periphery of the rotor reduce a space in the housing after volume expansion. A suction port communicating with the vacuum tank is opened in the expansion pump chamber which is formed in the pump chamber and gradually expands in volume to suck gas into the pump chamber, and suction air from the contraction pump chamber in which the volume gradually decreases to the discharge port In a vacuum pump that compresses and discharges the pump, near the position where the pump chamber starts expanding, away from the suction port
And an angle separated by a vane interval from the suction port.
The outer periphery of the rotor is closest to the housing wall
A pipe member penetrating therethrough and opening into the pump chamber is provided in a housing wall within a close angle position , and a small-diameter throttle portion is formed in a part of an inner periphery of the pipe member, and the pipe member is provided outside the housing. An operation detection device for a vacuum pump, wherein one end of a hose is connected to the opening, and the other end of the hose is connected to a connection port of a pressure switch provided at a position above the vacuum pump.