JPS5827108Y2 - Diaphragm pump - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a diaphragm pump, and is particularly suitable for supplying secondary air.

Conventional diaphragm pumps convert the movement of an eccentric cam in an engine into reciprocating motion using a lever, and transmit the reciprocating motion to a diaphragm via a shaft, and are known as fuel pumps and vacuum pumps.

One end of the lever is pressed against the eccentric cam by a spring, and the other end is connected in such a way that force is applied only in one direction, either pushing up or pushing down the shaft to which the diaphragm is directly connected, and the diaphragm is returned to its original position. was supposed to be done by spring force.

In addition, in order to produce a larger discharge amount with low rotation specifications and to make it more compact, a flat or dish-shaped diaphragm 1 is used.
A diaphragm pump with double actuation type was also devised.

In the case of a fuel pump, the discharge process is operated by the force of a spring in order to obtain a predetermined discharge pressure, and the discharge pressure is 0.2 to 0.3 kg/d, and the discharge flow rate is also small. In the case of an air pump for secondary air supply, a discharge pressure of 0.5 to 0.6 kg/d is required, and the discharge amount is also 10 times that of a fuel pump, so a diaphragm is required for a double-side operating type. The set load of the return spring must also be strong enough to produce a discharge pressure of 0.5 to 0.6 kg/d.In this way, the drive lever will not have to push or pull the shaft to operate the discharge. The force is ``force due to discharge pressure + spring set load + inertia force''
Since the pump will not operate without a stronger force, the force required to drive the drive lever is intermittent but extremely large, resulting in large losses as a load on the engine.
In addition, there was a problem with durability due to high surface pressure at the contact portion.

Furthermore, even in a dual-acting type with a single flat or dish-shaped diaphragm, the diaphragm is repeatedly rotated in reverse and forward, which causes problems in durability, noise, etc.

Therefore, the present invention prevents the diaphragm from reversing and obtains the same discharge performance as the conventional double-acting type by providing two diaphragms, and increases the rigidity of the diaphragm by providing a recess on the pressure receiving surface of the diaphragm. It is an object of the present invention to provide a diaphragm pump that does not require a guide such as a bush or a shilling, and also does not require a return spring by directly connecting a disk supporting the center of two diaphragms to a connecting rod to cause the diaphragm to reciprocate. shall be.

The embodiments of the present invention will be explained below with reference to the drawings: 1.2.
3 is the first to third housings, 4 is an eccentric circular cam or crank driven by an engine (not shown), and 5 is a connecting rod.
A cam or crank 4 is slidably fitted through a bearing 6 such as a metal or a bearing, and then fixed by a bolt 7 and a nut 8.

A center disk 9 is fixed to the upper end of the connecting rod 5 by screws 13, and the center disk 9 and two support plates 11a.

11b are two diaphragms 10a made of rubber.

The center portion of 10b is sandwiched and fixed with screws 12a and 12b.

The peripheral edge of each diaphragm 10a, 10b is the first. Second.
The first diaphragm 10a and the third housing 3 are sandwiched between the third housings 1 and 2 and fixed with screws 21.
and form the first pump chamber 19a, and the second diaphragm 1
0b and the first housing 1 is a second pump chamber 19b.
1. Second diaphragm 10a.

A suction chamber 20 is formed between 10b and the second housing 2.

And the first. Discharge valves 1 are provided in the third housings 1 and 3, respectively.
6a and 16b are also the support plate 11a.

11b is provided with suction valves 17a and 17b, and the first. Discharge pipes 23a and 2 are provided in the third housings 1 and 3.
3b, a suction pipe 22 is connected to the second housing 2.

In addition, each valve 16a. A cushion 18 made of resin or rubber is placed on the valve seat surfaces of the valves 16b, 17a, and 17b.

Reference numeral 14a denotes a bellow made of oil- and gasoline-resistant hard resin, such as the well-known Teflon resin or rubber, and when the ring 15 is driven into the first housing 1, the flange 1 of the bellows 14 is
4a is fixed to the first housing 1 in an airtight manner.

The head of the bellows 14 is connected to the connecting rod 5 and the center disk 9.
and is airtightly fixed by tightening the screw 13.

The housing surface 1a of the diaphragm pump body is in close contact with the engine body and is attached with bolts (not shown).

As shown in FIG. 2, a diaphragm 10a.

A recess 100 having a semicircular cross section in a free state is formed in a part of the pressure receiving surface of 10b in an annular shape.

Two diaphragms 10a and 10b are disposed with their surfaces opposite to the surface on which the recess 100 is formed facing each other.

On the other hand, the first. Diaphragm 10 of the third housing
Convex bulges 1 b , 3 a corresponding to the shape of the recess 100 when the diaphragms 10 a , 10 b are displaced most toward the housings 3 , 1 are located opposite to the recesses 100 formed by the diaphragms 1 b , 10 b. is a pretense.

In the above configuration, when the engine is started, the cam or crank 4 rotates in proportion to the engine speed.

Since this cam or crank 4 is eccentric, the connecting rod 5 is forced to perform a rocking reciprocating motion, and the center disk 9 and diaphragms 10a, 10b, which are directly connected to the connecting rod 5, also reciprocate, and the first. The second pump chambers 19a, 19b are expanded and compressed alternately.

When the center disk 9 moves upward in the figure, the first pump chamber 19a is in the compression stroke, so the discharge valve 16a opens and air is discharged from the discharge pipe 26a, and the second pump chamber 19b is in the expansion stroke. The suction valve 17b opens, and air is sucked in from the suction pipe 25 through the suction chamber 20.

Note that when the center disk 9 moves downward, the discharge valve 16
b is opened and air is discharged from the second pump chamber 19b, and at the same time, the suction valve 17a is sucked in.

Here, in a pump that performs reciprocating motion with rocking as in this example, the diaphragms 10a and 1ob are connected to the housing 3.
, even when the diaphragm 10a is displaced to the 1 side.
, 10b are displaced in an inclined state with respect to the housings 3 and 1.

Therefore, acceleration also occurs in the recesses 100 formed in the diaphragms 10a, 10b in a direction perpendicular to the reciprocating direction.

Normally, this acceleration component is the diaphragm 10a.

This causes torsional strain in the recess 100 of the diaphragm 10b, which is extremely harmful, but in the pump of this example, this acceleration component can be used to prevent the diaphragms 10a and 10b from colliding.

That is, an acceleration component in a direction perpendicular to the reciprocating direction is generated in the diaphragms 10a and 10b.
, 10b gradually come into contact with the convex portions 3a, 1b of the housing from their ends, thereby preventing them from making impactful contact all at once.

Furthermore, since the housings 1 and 3 have protrusions 1b and 3a, there is no put space in the pump chambers 19b and 19a, and the efficiency of the pump is also maximized.

In this way, one reciprocation of the center disk 9 performs two ejection operations, so the amount of ejection is nearly twice that of one ejection action per reciprocation. 7) The outer diameter can be reduced to about half, and the two diaphragms 10a, 10
Since b is disposed on one end side of the connecting rod 5, the length in the vertical direction in the figure hardly increases, so that the pump can be made smaller.

Furthermore, by directly connecting the connecting rod 5 to the cam or crank 4, the diaphragms 10a, 10b can be forcibly moved back and forth, so there is no need for a spring to return the diaphragms 10a, 10b. Since the required driving force is sufficient, the driving force is averaged, and the maximum value is about 1/2 or less of that of a conventional cam lever mechanism, so the engine load can be significantly reduced.

Furthermore, the two diaphragms 10a and 10b are in the recess 10.
0, and this recess 100 allows the diaphragm 10a to
, 10b, there is no need for bushings or cylinders to prevent lateral deformation of the diaphragms 10a, 10b due to the swinging and reciprocating movement of the connecting rod 5.

Further, since pressure is applied to each diaphragm 10a, 10b in only one direction, there is no fear of reversal, which is advantageous in terms of durability, sound, etc.

The cam or crank 4 may be integrated with the engine crankshaft or camshaft, or a crank mechanism may be provided in the pump body to drive the pump by a pulley.

In addition, in order to increase the rigidity and stroke, the recess 10
It is most desirable that the shape of 0 be semicircular in the free state, but it goes without saying that it does not necessarily have to be semicircular.

As mentioned above, the present invention simplifies the structure because it eliminates the need for guides and return springs such as bushes or cylinders to prevent rocking of the diaphragm, and eliminates the need for return springs. This has the excellent effect of reducing the driving force by more than half.

Further, since pressure is applied to each of the two diaphragms in only one direction, it is possible to prevent the diaphragms from reversing and to obtain a discharge performance equivalent to that of a conventional dual-action pump.

Moreover, since both diaphragms are arranged on one end side of the connecting rod, the pump can be implemented without increasing the size of the pump.

Furthermore, an annular recess is formed on the pressure-receiving surface of the diaphragm, and the housing is bulged with a convex part that corresponds to the shape of the small part when the diaphragm is displaced.This increases the rigidity of the diaphragm and prevents the diaphragm from colliding with the housing. The durability of the diaphragm is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing the shape of the diaphragm shown in FIG. 1 in a free state. 1.2, 3...Housing, 4...Eccentric circular cam or crank, 5...Connecting rod, 9...
...Center disk, 10a, 10b...
...Diaphragm, 19a, 19b...Pump chamber, 100...Recess.

Claims (4)

[Scope of utility model registration request] (1) A pair of diaphragms in which a concave portion is formed in an annular shape on a pressure receiving surface, a convex portion is formed in the opposite surface, and the membrane pressure is approximately equal, and the pair of diaphragms are formed in such a manner that the convex portion is formed in the pair of diaphragms. A center disk whose surfaces face each other and integrally support the center portions of each; a connecting rod that swings the pair of diaphragms back and forth through the center disk; and a surface in which a concave portion of each of the pair of diaphragms is formed. A housing is disposed facing each other and has a convex portion formed in a portion facing the recessed portion to correspond to the shape of the recessed portion when the diaphragm is displaced the most, and the housing and the pair of diaphragms are formed. a pair of pump chambers, a suction port for introducing air into the pump chamber, a suction valve for opening and closing the suction port, a discharge port for discharging air from the pump chamber, and a discharge valve for opening and closing the discharge port. A diaphragm pump, wherein one end of the connecting rod projects outside the pump chamber and is fitted into an eccentric circular cam or crank that rotates outside the pump chamber. (2) The diaphragm pump according to claim 1, wherein the suction port and the suction valve are provided on the center disk. (3) The diaphragm pump according to claim 1 or 2, wherein the discharge port and the discharge valve are provided in the housing. (4) The diaphragm pump according to any one of claims 1 to 3, wherein the pump chamber and the connecting rod are separated by a bellows.