JPH0343692A - Oil supply device in oil rotation vacuum pump - Google Patents

Abstract

PURPOSE:To regulate automatically the quantity of oil to be fed according to an oil viscosity change activated in response to an oil temperature, by providing a relief hole, a regulation valve and a resistance portion increasing the resistance of oil flow, at the middle of an oil supply passage supplying oil from an oil supply pump, to the inside of the cylinder chamber of a vacuum pump. CONSTITUTION:A two step type rotation fan rotation vacuum pump conducts exhaust by opening pushingly an exhaust valve 15 through the 2nd exhaust opening 14 after sucking into the inside of a cylinder chamber 6 through an exhaust passage 12 gas which has been sucked into the inside of a cylinder chamber 5 by the rotation of rotors 7,8 through the 1st step air suction opening 10. And at this time, oil from an oil pump 1 is being fed under pressure into respective cylinder chambers 5, 6 through oil supply passages 2, 3. In this instance, a relief hole 20 communicating with an oil sink is provided at a position near the pump 1 at the oil supply passage 2, and a regulation valve 21 whose opening is increased according to pressure on the pump 1 side, and a resistance portion 22 whose purpose is to increase the flow resistance of oil, are provided respectively at the oil supply passage 2 between the relief hole 20 and the cylinder chamber 5, and at the oil supply passage 2 between the relief hole 20 and the regulating valve 21.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an oil rotary vacuum pump in which the amount of oil supplied to a cylinder chamber is reduced in accordance with a change in oil viscosity, for example, in accordance with a decrease in viscosity. The present invention relates to a lubrication device that allows a pump to operate satisfactorily.

(Prior Art) A conventional oil supply system for an oil rotary vacuum pump is comprised of an oil pump 1 and an oil supply path 2.3, as schematically shown in FIG. The figure shows a two-stage rotary oil rotary vacuum pump, in which a 10th cylinder 7 and a 20th cylinder 8 are housed in a cylinder chamber 5.6 formed in a casing 4, and are connected to a common rotating shaft 9. It is designed to be driven. As the rotor rotates, gas is sucked into the cylinder chamber 5 from the first stage intake port 10 and exhausted from the first stage exhaust port ll to the exhaust passage 12,
Intake is drawn into the cylinder chamber 6 through the second stage intake port 13 connected to the exhaust passage 12, and the exhaust valve 15 is drawn through the second stage exhaust port 14.
It is designed to be pushed open against a spring to exhaust gas.

(Problem to be solved by the invention) In a conventional vacuum pump of this type, the cylinder chamber 5.6
The oil supplied within has two important roles. It has a lubricating effect and a sealing effect.

If we simply consider only the two effects, a larger amount of oil would be better, but if we also consider the performance of the vacuum pump, a higher amount of oil would be detrimental. These are the operating noise and the vacuum level reached. When the amount of oil in the cylinder is large, the operating noise becomes higher as it approaches the ultimate vacuum, and when the amount of oil is too large, the operating noise becomes higher.

That is, when the amount of oil is appropriate, the two-stage vacuum pump clears the order of IO-'Torr, but if the amount of oil is too large, the limit is on the order of 10-'Torr. On the other hand, if the amount of oil is too small, the oil film will break and the sealing effect will be reduced, resulting in a lower ultimate vacuum and poor lubrication, resulting in seizure.

Normally, when the temperature is low, the viscosity of oil is high and it is difficult to flow, and when the temperature is high, the viscosity is low and it is easy to flow. Such a change in viscosity due to oil temperature is a bad condition for the vacuum pump. In other words, when the vacuum pump is started, the oil temperature is low, so the circulation of the oil is poor, and the above-mentioned adverse effects are caused when the amount of oil is too small.
In other words, there is a problem that the rise to the ultimate vacuum is poor and there is a risk of seizure, and as the temperature of the oil rises, the above-mentioned adverse effects of using too much oil, that is, the noise increases and the degree of vacuum decreases. There is a problem with coming.

An oil temperature control device that keeps the oil temperature within an appropriate range could be considered as a solution to this problem, but this usually requires both heating means and cooling means. This is not desirable because it requires a large assembly and increases equipment costs.

An object of the present invention is to solve the above-mentioned problem based on the change in viscosity due to temperature of oil in a vacuum pump without using a large-scale device.

(Means for Solving the Problems) This invention provides an oil supply device having an oil supply device configured to forcefully feed oil in an oil reservoir chamber into a cylinder chamber via an oil supply path by an oil supply pump connected to a rotor shaft. In the rotary vacuum pump, a relief hole communicating with an oil reservoir chamber is provided in the middle of the oil supply path, and a valve is biased in a valve closing direction by a spring in the oil supply path between the relief hole and the cylinder chamber. A regulating valve configured to increase its opening degree in accordance with the magnitude of pressure on the oil supply pump side is provided to increase oil flow resistance in the oil supply path between the relief hole and the regulating valve. The invention is characterized in that it is provided with a resistance section that causes the

[For production]

According to the above means, when the vacuum pump is started, the oil supply pump also operates, or when the initial oil temperature is low, the amount of oil supplied to the cylinder chamber is large, and when the oil temperature becomes high due to 11 continuous operation, etc. In this state, the oil supply device operates so that the amount of oil supplied to the cylinder chamber is reduced. In other words, when the oil temperature is low, the viscosity is high, so it is difficult to discharge from the relief hole, and the oil pressure on the oil supply path side.

The flow becomes high, opening the regulating valve wide and increasing the flow.

On the other hand, since the viscosity is low at oil temperature or commercial conditions,
It is easily discharged from the relief hole, the oil pressure on the oil supply path side becomes low, and the opening of the regulating valve becomes small, reducing l1tt. The presence of the flower part stabilizes the oil pressure of the oil supply path and keeps the valve body stable.

The amount of oil supplied becomes stable.

(Example) An example of the present invention will be described with reference to FIGS. 1 and 2. This embodiment was implemented in the conventional two-stage rotary vane type oil rotary vacuum pump explained using FIG. 20. Regulating valve 21. A resistor section 22 is provided, and since the other parts are the same as those shown in FIG. 3, they will be designated by the same reference numerals and their explanation will be omitted.

The relief hole 20 is provided in the oil supply path 2 at a position close to the oil supply pump 1 so as to communicate with an oil reservoir chamber (not shown). The size of the hole is determined by the resistance of the oil supply path 2 and the pump l.
Although it is determined based on the capacity etc. of the oil supply path 2, it is necessary to ensure that an appropriate supply pressure is obtained on the oil supply path 2 side. Note that this relief hole 2
0 may be constituted by a valve whose opening degree can be adjusted as necessary.

As shown in an enlarged view in FIG. 2, the regulating valve 21 is provided with a valve body 26 in a valve chamber 27 that slides while fitting into a fixed vibrator 25, and one end wall of the valve chamber 27 is connected to a valve seat 28. As this valve seat 2
8, the valve body 26 is pressed by the spring 29, and the valve seat 28 side of the valve body 26 is connected to the recess 30 communicating with the tip opening of the vibrator 25.
is formed. The tip end of the vibrator 25 on the side of the valve body 26 is obliquely cut off to form the tip opening, and a sealing member 31 made of fluororesin or hard rubber is fitted to the base end or its outer periphery. It is fixedly supported so as to be located at the center of the inner hole 32 formed in the casing 4 via the casing 4. In the figure, reference numeral 33 denotes a spring chamber, which is formed between the inner hole 32 and the valve chamber 27 so as to coaxially continue therewith.

The resistance part 22 is provided in the middle of the oil supply path 2 from the relief hole 20 to the regulating valve 21, and includes a circular hole 34, a screw 35 fitted in the circular hole 34, and a screw 35 inserted in the inner hole 32. The screw member 36 inserted into the 4! has been completed.

The screw member 36 has a threaded groove 37 on the outer periphery of a short columnar body, and has diametrical grooves 38 and 39 at both ends. The circular hole 34 coaxially communicates with the inner hole 32, has an end reaching the outer surface of the casing 4, and has a female threaded portion 40 at the end. The screw 35 is screwed into the female threaded portion 40, one end abuts against the screw member 36, and the other end protrudes outside and is fixed by being screwed into the nut 4. The oil supply path 2 on the oil supply pump l side communicates with the inner side of the female threaded portion 40 of the circular hole 34. The oil sent from the oil supply pump 1@ is connected to the screw 35.
The threaded member passes through a thin spiral passage formed by the thread groove and the inner surface of the circular hole 34, and further passes through a thin spiral passage formed by the groove 39 of the threaded member 36, the circular hole 32 and the threaded groove 37, and the threaded member. 36 and reaches one end of the circular hole of the vibrator 25.

A vacuum pump having a lubricating device configured in this way is
Upon starting, the oil supply pump 1 is operated and oil is supplied to the cylinder chamber 6 and then to the cylinder chamber 5. The temperature of ordinary oil is low at the beginning of operation and gradually rises.

If the amount of oil discharged from the oil supply pump l is constant or the temperature of the oil is low, the viscosity of the oil is high and the relief hole 2
Since it is difficult to be relieved from zero, the oil pressure that reaches the recess 30 of the valve body 26 is relatively high pressure. As a result, the valve body 26 is lifted significantly, and an amount of oil corresponding to the lift and pressure is supplied to the cylinder chamber 6. When the temperature of the oil is high, the oil has a low viscosity and is easily relieved from the relief hole 20, so the oil pressure that reaches the recess 30 of the valve body 26 is relatively low. As a result, the lift of the valve body 26 becomes smaller than when the oil is at a low temperature, and an amount of oil corresponding to the lift and pressure is supplied to the cylinder chamber 6. That is, when the oil temperature is low, for example at the beginning of operation, the amount of yuzu supplied to the cylinder chamber 6 is relatively large, and when the oil temperature is high, for example during long-time #I operation, the amount of oil supplied to the cylinder chamber 6 is relatively large. The supply amount will be relatively small.

Therefore, as a vacuum pump, the amount of oil supplied is increased when the oil temperature is low and the rotation is poor, and less when the oil temperature is high and the rotation is good. This solves the problem of supply amount depending on temperature.

In the above embodiment, the spring 29 can be made to correspond to oils having different characteristics by changing the spring constant.

(Effects of the Invention) According to the present invention, by providing a relief hole, a resistance portion, and a regulating valve in an oil supply path having a relatively simple configuration,
Since the amount of oil supplied into the cylinder chamber is automatically adjusted to the appropriate amount according to changes in viscosity due to oil temperature, the amount of oil supplied into the cylinder chamber is automatically adjusted to the appropriate amount according to changes in viscosity due to oil temperature. Problems caused by insufficient supply due to low oil temperature, or problems caused by oversupply due to rise in oil temperature during continuous operation are eliminated. That is, there is no risk of seizure of the vacuum pump, low noise, high ultimate vacuum (1), and an oil supply system that is easy to achieve and is advantageous in terms of cost.

[Brief explanation of drawings]

Figure 1 shows one embodiment of this invention! FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a longitudinal front view showing the general structure of an example of a conventional vacuum pump. l...Oil supply pump, 2...Oil supply path, 4...
...Casing, 6...Cylinder chamber of second stage vacuum pump, 8...Rotor of second stage vacuum pump, 9...
・Rotating shaft, 20...Relief hole, 21...Adjusting valve, 22...Resistance part, 26...Valve body, 29...
... Spring, 31... Seal member, 35... Spring, 36... Spring member, 37... Spring groove, 38.
39...Groove. ! P11 Figure 3

Claims (1)

[Claims] (1) In an oil rotary vacuum pump having an oil supply device configured to forcefully feed oil in an oil reservoir chamber into a cylinder chamber via an oil supply path by an oil supply pump connected to a rotor shaft, the oil supply path A relief hole communicating with the oil reservoir chamber is provided in the middle, and a valve body biased in the valve closing direction by a spring is provided in the oil supply path between the relief hole and the cylinder chamber to reduce the pressure on the oil supply pump side. A regulating valve is provided whose opening degree increases depending on the size of the regulating valve, and a resistance portion is provided in the oil supply path between the relief hole and the regulating valve to increase oil flow resistance. Refueling device.