JPS6218713Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pump used as means for pumping fluid such as air, and more particularly to a pump whose driving source is negative pressure of the fluid.

As an example of exhaust gas purification for automobiles, etc., air is supplied to the exhaust system for exhaust gas purification by using the pulsating negative pressure generated within the exhaust system of the engine, as illustrated in Figure 1. Secondary air supply devices are widely used.

The secondary air supply device shown in the figure includes a reed valve 1 having an inflow port and an outflow port, and a reed made of an elastic thin plate is attached to one side of a base provided with a ventilation hole to open and close the ventilation hole. A check valve device, which is disposed in the internal cavity of the casing 2 to allow airflow from the inlet side to the outlet side and prevents airflow in the opposite direction, is connected to the exhaust system 3 of the engine (not shown). The device is placed between air cleaners and draws clean air into the exhaust system by the pulsating negative pressure generated in the exhaust system, and the clean air purifies the exhaust gas.

In the above-mentioned secondary air supply device, clean air is supplied by the suction force of the negative pressure within the exhaust system, so only the negative pressure portion of the pressure pulsations generated within the exhaust system is utilized. The positive pressure part does not contribute to the secondary air supply, and the negative pressure part of the pressure pulsation is generally smaller than the positive pressure part.
Depending on the secondary air supply device, it may not be possible to obtain a sufficient amount of secondary air supply, and furthermore, in the high-speed rotation region of the engine, there may be no negative pressure part in the pressure pulsations in the exhaust system. There are cases where the secondary air supply cannot be obtained, and in order to supply as much secondary air as possible, it is necessary to connect the area where the pressure pulsation is maximum. There will be restrictions on location selection.

The inventor considered the above-mentioned problems with the conventional secondary air supply system that utilizes the pulsating negative pressure in the exhaust system, and also focused on the almost constant negative pressure that occurs on the intake manifold side of the engine. As an operating source for a diaphragm pump that pressurizes and supplies fluid through the reciprocating action of a diaphragm, there is a device that performs the pumping action of the diaphragm by alternately applying the negative pressure and atmospheric pressure in the suction manifold described above. I devised it.

In the pump of the present invention, the drive chamber of the diaphragm pump that pressurizes fluid through reciprocating operation is connected to the negative pressure generating section of the intake manifold of the engine so that the air in the drive chamber is sucked into the intake manifold side. A ventilation hole that communicates the drive chamber with the atmosphere and a switching valve that alternately closes and opens the ventilation hole are installed, and while the switching valve remains closed, the air in the drive chamber is sucked to the negative pressure side and the diaphragm When the diaphragm performs a suction stroke and the switching valve opens, atmospheric pressure is introduced into the drive chamber to cause the diaphragm to perform a discharge stroke.
By alternately repeating the closing and opening of this switching valve, the diaphragm continues to perform the pumping action.

The changeover between closing and opening of the switching valve is achieved by making it possible to relatively move the connecting rod connected to the diaphragm and the valve stem connected to the switching valve in the axial direction by a certain distance, and by reciprocating stroke in the axial direction. are brought about by connecting them to each other with joint means that move simultaneously near their respective ends.

That is, at the beginning of the suction stroke of the diaphragm due to suction of negative pressure, the switching valve does not follow the movement of the diaphragm and remains closed, and when the suction stroke reaches near the end,
It moves with the movement of the diaphragm and becomes open, and as the switching valve opens, the pressure inside the drive chamber immediately becomes equal to atmospheric pressure, and the diaphragm performs a discharge operation due to the pressing force of the spring means that biases the diaphragm, and the switching valve opens. remains open at the beginning of the discharge stroke, moves with the diaphragm and returns to the closed state when the discharge stroke reaches the end, and the air in the drive chamber is sucked in again, causing the diaphragm to resume the suction stroke. It consists of:

While negative pressure is introduced into the drive chamber, the opening/closing of the switching valve that follows the suction/discharge stroke of the diaphragm described above and the switching of the discharge/suction stroke of the diaphragm that follows the opening/closing of the switching valve occur. The pressurization and supply of clean air continues repeatedly, and the pump operation stops when the introduction of negative pressure stops.

The illustrated embodiment will be described below.

In the embodiment shown in FIG. 2, an inlet 5 and an outlet 6 are provided at one end of the casing, which has a substantially cylindrical shape and has an internal cavity, and an operating negative pressure inlet 10 is provided in the middle. A partition plate 16 with a ventilation hole 17 is arranged on the opposite side, and a suction valve 7 and a discharge valve 8 are provided at the suction port 5 and the discharge port 6, and the partition plate 16 is arranged in the internal cavity and connected to the inner wall of the casing. The diaphragm 11 partitions the internal space into a pump chamber 12 that communicates with the suction port 5 and the discharge port 6, and a drive chamber 13 that communicates with the operating negative pressure inlet 10, and the diaphragm 11 is attached to the pump chamber 12 side. A switching valve 20 is provided with a spring means 15 disposed within the drive chamber 13 and has a substantially disk shape and opens and closes the ventilation hole 17.
is attached to the atmospheric side of the partition wall 16, and a valve rod 23 connected to the switching valve 20 passes through the partition wall 16 while maintaining sliding friction, and a connecting rod 21 connected to the center of the diaphragm 11 The valve stem 23 is
The switching valve 20 is capable of relative movement in the axial direction, and is combined so as to move simultaneously when near the end of the relative movement in the axial direction in each reciprocating direction.
A filter 25 is arranged on the atmosphere side.

When the above-mentioned embodiment is used as a secondary air supply device for purifying engine exhaust gas, the inlet 5 is connected to an air cleaner which is a clean air supply source, and the discharge port 6 is connected to a secondary air supply destination. It is connected to a certain exhaust system, and the operating negative pressure inlet 10 is connected to, for example, a negative pressure generating part of an intake manifold of an engine via a control means, so as to perform the pumping action described below.

When negative pressure is introduced into the drive chamber 13 through the operating negative pressure inlet 10 by the control means, the diaphragm 1
1 is attracted toward the partition wall 16 to start the suction stroke, and at the beginning of the suction stroke, the connecting rod 21 of the diaphragm 11 and the switching valve 20
The valve stems 23 move relative to each other, and the switching valve 20 continues to close the ventilation hole 17 due to the friction of the valve stem 23 against the through hole of the partition wall 16.
The suction stroke of the diaphragm 11 due to negative pressure suction in the valve 3 is continued, and when the suction stroke reaches near the end, the connecting rod 21 and the valve stem 23
are brought into abutting state and move simultaneously, the blockage of the ventilation hole 17 by the switching valve 20 is rapidly released and the atmosphere is introduced into the drive chamber 13, so that the suction effect on the diaphragm 11 is released and the diaphragm 11 is urged toward the pump chamber 12 by the spring means 15 to start a discharge stroke.

At the beginning of the discharge stroke, the connecting rod 21 and the valve rod 23 move relative to each other, and the switching valve 20 remains open due to contact friction between the valve rod 23 and the through hole of the partition wall 16, so that the diaphragm 11 The discharge stroke continues, and when the discharge stroke reaches near the end, the relative movement of the connecting rod 21 and the valve rod 23 ends, and the switching valve 20 follows the discharge stroke of the diaphragm 11 and closes the vent hole 17. Therefore, the air in the drive chamber 13 is sucked through the operating negative pressure inlet 10,
Diaphragm 11 begins the suction stroke again.

As described above, the pump of the present invention has an inlet with a suction valve and a discharge outlet with a discharge valve at one end, and a partition wall with a ventilation hole at the other end. The internal space is divided into a pump chamber communicating with the suction port and the discharge port and a drive chamber communicating with the working negative pressure inlet. A switching valve for opening and closing the ventilation hole is arranged on the atmospheric side of the partition wall, and a connecting rod and a switching valve are connected to the diaphragm. The valve stem is coupled to the valve stem and passes through the partition wall, and the valve stem is connected so as to be relatively movable by a certain distance, thereby producing the following effects.

It is possible to cause the diaphragm to operate the pump simply by connecting the operating negative pressure inlet to a negative pressure source and introducing negative pressure into the drive chamber.

That is, by connecting the operating negative pressure inlet to the negative pressure generating part of the engine's intake manifold, for example, and connecting the discharge port to the secondary air supply target part to introduce steady negative pressure into the drive chamber, the drive chamber The diaphragm, which is attracted to the negative pressure of Near the end of the discharge stroke, the suction stroke is restarted by closing the switching valve caused by the connecting rod and the valve stem, so while the negative pressure continues to be introduced into the drive chamber, The diaphragm continues to pump.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing an outline of an example of a secondary air supply device according to the prior art, and FIG. 2 is a sectional view of an embodiment of the present invention. 1...Reed valve, 2...Casing, 3...
...Exhaust system, 5...Intake port, 6...Discharge port, 7...
Suction valve, 8...Discharge valve, 10...Working negative pressure inlet, 11...Diaphragm, 12...Pump chamber,
13... Drive chamber, 15... Spring means, 16... Partition wall, 17... Vent hole, 20... Switching valve, 21...
...Joint rod, 23...Valve stem, 25...Filter.

Claims (1)

[Scope of utility model registration request] A partition wall 16 having ventilation holes 17 is disposed at one end to form an internal cavity, and the partition wall 1
A casing is provided with an inlet 5 and an outlet 6 at the opposite end of the casing, and an operating negative pressure inlet 10 is attached in the middle, an inlet valve 7 that opens and closes the inlet 5, and A discharge valve 8 that opens and closes, and an internal space of the casing that connects the suction port 5 and the discharge port 6.
a pump chamber 12 communicating with the operating negative pressure inlet 1;
0, a diaphragm 11 with a connecting rod 21 extending toward the partition wall 16, and a switch attached to the atmosphere side of the partition wall 16 for opening and closing the ventilation hole 17. A valve 20, a valve rod 23 coupled to the switching valve 20, passing through the partition wall 16, and connected to the connecting rod 21 so as to be movable a certain distance, and the diaphragm 11 toward the pump chamber 12 side. Spring means 1 for biasing
5.