JPH06185466A - Diaphragm vacuum pump - Google Patents

Abstract

PURPOSE:To improve compression efficiency by eliminataing stagnation of gas in a recessed part created by bending and deforming along an air intake hole and an air exhaust hole. CONSTITUTION:Rotation of an electric motor is transmitted to a diaphragm 8 through an eccentric shaft 4 and a connecting rod 6. In air intake space 17 formed in a pump head 10, a rubber valve 11 is fixed by a valve holding body 12 having an air intake hole 19a, and in air exhaust space 18, a rubber valve 11 is fixed by a valve holding body 12a having air exhaust holes 20a and 4Oa. When a pump is operated, air is sucked through air intake holes 19a and 19, and is exhausted through air exhaust holes 20 and 20a, but at this time, gas in a valve recess 11b bent and deformed by the air intake hole 19a and the air exhaust hole 20 is sucked or exhausted through a newly arranged air intake hole 49 and the air exhaust hole 40a without causing stagnation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm vacuum pump, and more particularly to a diaphragm vacuum pump having an improved structure near a plate-like valve to prevent a decrease in compression efficiency due to air stagnation.

[0002]

2. Description of the Related Art A conventional diaphragm vacuum pump is constructed, for example, as shown in FIGS. FIG. 2 is a plan view of the diaphragm vacuum pump, and FIG. 3 is a side view of the diaphragm vacuum pump with a part thereof cut away. In the figure, a pair of casings 2, 2 are arranged on both sides of the electric motor 1 and the casing 2 is fixed to the electric motor 1 by a plurality of fixing bolts (only one is shown in the figure) 2a. There is. Rotating shafts 3 are attached to both sides of the electric motor 1 so as to be located inside the casing 2. (The figure shows only one side.)

An eccentric shaft 4 is fixed to the outer circumference of the rotary shaft 3 by a set screw 4a, and a connecting rod 6 is connected to the outer circumference of the eccentric shaft 4 via a ball bearing 5a. It is fixed in the radial direction. Further, a flywheel 7 is fixed to the end of the rotary shaft 3 on the axially outer side of the eccentric shaft 4 by a set screw 7a. The inner peripheral portion of the diaphragm 8 is fixed to the front end portion of the connecting rod 6 so as to be sandwiched by the diaphragm holding body 9, and the outer peripheral portion of the diaphragm 8 is fixed to the front end portion of the casing 2 by the pump head 10. It is fixed so that it is sandwiched between.

At the outer end of the pump head 10 in the radial direction, a plate valve 11 made of rubber is sandwiched between valve holding bodies 12 and fixed by a countersunk screw 12a.
The inner side in the radial direction of is the compression chamber 13. At the outer end (upper end in the figure) of the pump head 10, a pump head cover 15 is capped with a head gasket 14 sandwiched therebetween. As shown in FIG. 2, the pump head 10 has a partition wall 16 to partition the outer space of the valve 11 into two spaces, one serving as an intake space 17 and the other serving as an exhaust space 18. The pump head 10 has an intake hole 19 and an exhaust hole 2
0 indicates that the valve holder 12 has an intake hole 19a and an exhaust hole 20a.
Are formed and are opened and closed by the valve 17, respectively. The intake hole 19 is formed by the intake pipe 2
1, the exhaust hole 20 is connected to the exhaust pipe 22.

The above-described structure is similarly provided on the pair of casings 2 and 2, and the hose nipple 2
3, the elbow 24, and the tube 25, respectively. In the figure, 27 is a casing cover, 28 is a handle, 29 is a base plate, 30 is a rubber leg, and 31 is a rubber plate.
Is a motor cover, 32 is a switch, and 33 is an operating time integrating type hour meter.

How to connect the intake space 17 and the exhaust space 18 formed in the above-mentioned pair of pump heads 10 will be described.
This will be described with reference to FIGS. 5 and 6. The hatched portion in the figure corresponds to the intake space 17, and the other corresponds to the exhaust space 18. FIG. 5 shows a connection method for three-stage compression, and FIG. 6 shows a connection method for four-stage compression. The arrows in the figure show how the gas flows.

In the above-mentioned three-stage compression (FIG. 5), the intake spaces 17 of the two pump heads 10 formed in the one casing 2 are connected in parallel and integrated. Similarly, the exhaust spaces 18 are combined into one and connected to the intake spaces 17 of the two pump heads 10 formed in the other casing 2, and the exhaust space 18 is formed in the same casing 2 as the other pump head. It is connected to the space 17 for intake. Further, in the four-stage compression (FIG. 6), two pump heads 10 formed on one casing 2 are connected in series, and the exhaust space 18 of the second stage and the other casing 2 are formed. Is connected to the first stage intake space 17 of the two pump heads 10 connected in series.

Further, gas flows into the intake space 17 from the intake pipe 21 provided at the upper end of the pump head cover 15 located on the right side in FIGS. 2 and 3, and flows into the compression chamber 13 via the valve 11. On the other hand, the compressed gas is exhausted from the exhaust pipe 20 provided at the upper end of the pump head cover 6 located on the left side.

[0009]

The conventional structure described above has the following problems. That is, the valve 11 is opened and closed by the reciprocating movement of the connecting rod 6 when the pump is operating, but is located in the intake space 17 during the descending stroke (intake process) of the connecting rod 6 in FIGS. 4A and 4B. The valve 11 opens the intake hole 19a of the valve holder 12 and intakes air into the compression chamber 13 through the intake hole 19 of the pump head 10 in the direction of the arrow (FIG. (B)). At this time, the valve 11 located in the other exhaust space 18 closes the exhaust hole 20 of the pump head 10. Therefore, the valve 11 is bent along the exhaust hole 20 like 11a to form a recess 11b.

On the other hand, during the ascending stroke (exhaust stroke) of the connecting rod 6, the valve 11 located in the intake space 17 is
The valve 11 located in the other exhaust space 18 while closing the intake hole 19a of the valve holder 12 is the exhaust hole 2 of the pump head 10.
0 is opened and air is exhausted through the exhaust hole 20a of the valve holder 12a. At this time, the valve 11 in the intake space 17 is
A dent 11b is formed by bending along 9a. As a result, during pump operation, when the valve 11 of the intake space 17 is in the open state ((b) in the figure), the gas contacts the upper wall of the intake hole on the pump head 10 and gas is trapped in the recess 11b. As a result, the effective pump exhaust action is hindered, and the compression efficiency is reduced.

The present invention solves the above problems,
An object of the present invention is to provide a diaphragm vacuum pump capable of preventing the deterioration of compression efficiency by improving the shape of the intake hole and the exhaust hole to eliminate the stagnation of the gas.

[0012]

To achieve the above object, the present invention provides a connecting rod that reciprocates the rotation of an electric motor through an eccentric shaft, and a diaphragm fixed to the head of the connecting rod. And a pump head for fixing the outer periphery of the diaphragm, a rubber plate valve arranged on the upper surface of the pump head, and a valve holder for fixing the valve, and the pump head is provided on the pump head. It is characterized in that the intake hole and the exhaust hole provided in the valve holder are also formed in the movable portion of the valve.

[0013]

When the vacuum pump is operated, the connecting rod reciprocates the rotation of the electric motor through the eccentric shaft. The valve opens and closes due to the reciprocating motion of the connecting rod, and a recess is formed along the intake hole and the exhaust hole. To be done. Therefore, it is possible to prevent a decrease in compression efficiency.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1A is a partial cross-sectional side view of a diaphragm vacuum pump showing one embodiment of the present invention, and FIGS. 1B and 1C.
FIG. 4 is an explanatory view of a main part of a valve part. In the figure, the same reference numerals as those shown in FIGS. 4 (a) and 4 (b) indicate the same or similar parts, the description thereof will be omitted, and the parts different from those of the figure will be mainly described.

In this embodiment, an intake hole 49 is newly provided in the movable part of the valve, which is closer to the support portion of the valve 11, of the conventional intake hole 19 located in the intake space 17 of the pump head 10. On the other hand, the intake space 1 is separated by the partition wall 16.
7 and the valve holder 1 located in the exhaust space 18 arranged side by side
In the movable part of the valve 2a inside the valve 11 near the support part,
Unlike the conventional example (FIG. 5) in that the exhaust hole 40a is newly provided, there is no change in other points.

The new intake hole 49 and the new exhaust hole 40a
Is formed smaller than the movable part of the valve 11,
These valves 11 are prevented from being drawn into the intake hole 49 and the exhaust hole 40a.

According to this embodiment, as in the conventional example (FIG. 5), the valve 11 is opened and closed by the reciprocating movement of the connecting rod 6 by the rotation of the eccentric shaft 3 during the operation of the vacuum pump, and the connecting rod is opened. During the descent (intake) stroke of 6, the valve 11 in the exhaust space 18 is bent and deformed (11a) along the exhaust hole 20 of the pump head 10 to form a recess 11b, but the gas in the recess 11b is During the ascending (exhaust) stroke, the exhaust gas passes through the exhaust hole 40a newly provided in the valve holder 12a, and is exhausted as shown in FIG. 1 (c). Similarly, during the ascending (exhaust) stroke of the connecting rod 6, the valve 11 in the intake space 17 is curved and deformed (11a) along the intake hole 19a of the valve holder 12 to form a recess 11b. The gas in the portion 11b is introduced through the intake hole 49 newly provided in the pump head 10 during the descending (intake) stroke.
As shown in FIG. 1 (b), the air is sucked in without delay. Therefore, it is possible to prevent a decrease in compression efficiency due to air stagnant in the recess 11b of the valve 11 in the conventional example.

The present invention is not limited to the above-mentioned embodiment. For example, a groove that communicates with the conventional intake hole 19 and the exhaust hole 20a may be provided on the wall where the recessed portion comes into contact, and the gas in the recessed portion 11b may be guided to the intake hole 19 and the exhaust hole 20a. Further, the intake hole 19 and the exhaust hole 20a may be formed as one larger hole, and a part of the hole may be arranged so as not to be pulled in by the movable part of the valve 11 so as to be caught in the recessed part.

Next, the results of measuring the ultimate pressure will be shown. The measuring device is Nippon Vacuum Technology Co., Ltd., GP-2A
Pirani vacuum gauge was used. As the measuring method, after connecting the gauge head of the vacuum gauge to the intake pipe 21 so that no air leaked out, the diaphragm vacuum pump was operated and the indicated value after 1 minute was taken as the measured value. Further, as the objects of measurement, the three-stage compression product of the present example is 5, the three-stage compression conventional product is five, the four-stage compression of the present embodiment product is five, and the four-stage compression conventional product is five. It is a stand. The measurement result is shown in FIG. As is apparent from FIG. 7, in the case of the products of this embodiment, the ultimate pressure is improved in comparison with the conventional products.

[0020]

As described above, according to the present invention,
A connecting rod that reciprocates the rotation of the electric motor through an eccentric shaft, a diaphragm fixed to the head of the connecting rod, a pump head that fixes the outer periphery of the diaphragm, and a pump head that is arranged on the upper surface of the pump head. A rubber plate-shaped valve and a valve holder for fixing the valve are provided, and an intake hole provided in the pump head and an exhaust hole provided in the valve holder are provided in a movable portion of the valve. Due to the formation, even if the valve contacts the upper wall when the valve is open, there is no stagnation of gas, and it is possible to prevent a reduction in compression efficiency.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, (a) is a side view showing a diaphragm vacuum pump with a part thereof cut away, and (b).
And (c) are explanatory views of the main part of the valve part.

FIG. 2 is a view showing a conventional example, and is a plan view of a diaphragm vacuum pump.

FIG. 3 is a side view showing a conventional example in which a diaphragm vacuum pump is partially cut away.

FIG. 4 is a view showing a conventional example, (a) is a side view showing a diaphragm vacuum pump with a part thereof cut away, and (b) is an explanatory view of a main part of a valve portion.

FIG. 5 is a schematic diagram showing a connection example of piping for three-stage compression.

FIG. 6 is a schematic view showing an example of connection of piping for four-stage compression.

FIG. 7 is a diagram showing a result of measuring ultimate pressures of the diaphragm vacuum pump of the present embodiment and a conventional diaphragm vacuum pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 3 Rotating shaft 4 Eccentric shaft 6 Connecting rod 8 Diaphragm 10 Pump head 11 Plate valve 12, 12a Valve holding body 13 Compression chamber 17 Intake space 18 Exhaust space 19 Intake hole 20 Exhaust hole 21 Intake pipe 22 Exhaust pipe 40a Exhaust hole 49 Intake hole

Claims (1)

[Claims] 1. A connecting rod that reciprocates the rotation of an electric motor through an eccentric shaft, a diaphragm fixed to the head of the connecting rod, a pump head that fixes the outer periphery of the diaphragm, and a pump head of the pump head. A rubber plate valve disposed on the upper surface and a valve holder for fixing the valve are provided, and an intake hole provided in the pump head and an exhaust hole provided in the valve holder are Diaphragm vacuum pump characterized in that it is also formed in the movable part of.