JPH037596Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oil supply device for an oil rotary vacuum pump.

[Prior Art] As described in Japanese Patent Publication No. 58-7840, an oil rotary vacuum pump pumps oil in an oil reservoir into a cylinder chamber while rotating a rotor fixed to a rotor shaft in the cylinder chamber. The negative pressure is introduced into the cylinder chamber. This allows the vacuum pump to
An oil film is formed between the rotor and the cylinder interior wall to ensure rotor lubrication and airtightness between the rotor and the cylinder interior wall.

[Problems that Koan attempts to solve] However, the conventional oil rotary vacuum pump described above sucks the oil in the oil reservoir chamber into the cylinder chamber by the negative pressure in the cylinder chamber, so it is difficult to operate the vacuum pump. It is difficult to introduce oil stably into the cylinder chamber at all times. Further, the negative pressure remaining in the cylinder chamber when the vacuum pump is stopped continues to suck oil, introducing a large amount of oil into the cylinder chamber, making it difficult to restart the vacuum pump smoothly.

In addition, in conventional oil rotary vacuum pumps, the amount of oil supplied into the cylinder chamber is not adjusted according to changes in oil temperature, so the oil temperature changes from a low temperature at startup to a high temperature during steady operation. If the oil migrates and the viscosity of the oil decreases, it is likely that an oil film will break inside the cylinder chamber. This lack of oil film impairs the lubricity and airtightness of the vacuum pump, degrading pump performance.

The purpose of the present invention is to stabilize the supply state of oil into the cylinder chamber and to stably maintain pump performance such as lubricity and airtightness even when the oil temperature changes.

[Means for Solving the Problems] The present invention provides an oil supply system for an oil rotary vacuum pump that can supply oil from an oil reservoir into a cylinder chamber while a rotor fixed to a rotor shaft is rotated within the cylinder chamber. The device includes an oil supply pump connected to the rotor shaft and capable of pumping oil in the oil reservoir chamber into the cylinder chamber through an oil supply path, and an oil supply pump that is connected to the oil supply path to maintain negative pressure in the cylinder chamber during vacuum pump operation. As the temperature of the oil increases, the on-off valve opens and closes against negative pressure in the cylinder chamber when the vacuum pump is stopped, and the relief passage is formed by branching from the upstream side of the oil supply path where the on-off valve is installed. and passage resistance adjusting means provided with a passage resistance adjuster made of a shape memory alloy that increases the passage resistance of the relief passage.

[Operation] According to the present invention, the oil supply pump is driven in conjunction with the operation of the oil rotary vacuum pump, and the oil in the oil reservoir chamber that is pressure-fed by the oil supply pump is supplied into the cylinder chamber through the on-off valve. becomes. The on-off valve opens when the vacuum pump is in operation and closes when the vacuum pump is stopped. Therefore, during operation of the vacuum pump, oil is always stably supplied into the cylinder chamber immediately after starting. Furthermore, when the vacuum pump is stopped, unnecessary inflow of oil into the cylinder chamber can be reliably blocked. Furthermore, according to the present invention, as the oil temperature rises,
The shape memory alloy passage resistance adjuster increases the resistance of the relief passage, suppressing oil relief and increasing the supply of oil into the cylinder chamber. Even if the temperature decreases, the oil film will not run out. Therefore, even if the oil temperature changes, pump performance such as lubricity and airtightness does not change, and it is possible to stably maintain pump performance from startup to steady operation.

Note that Japanese Utility Model Application Publication No. 18879/1987 proposes a compressor oil supply device in which a shape memory alloy on-off valve is provided in an oil supply hole that supplies oil to the low pressure side of a compression element. However, this shape memory alloy on-off valve only has the function of switching and setting the oil supply hole to either fully open or fully closed. For this reason, the opening degree is not adjusted in the range of fully closed to fully open in response to changes in oil temperature, and the amount of oil supplied is not controlled to increase or decrease.

[Example] Fig. 1 is a sectional view showing the main parts of an oil rotary vacuum pump to which the present invention is applied, Fig. 2 is a cutaway view of a part along the - line in Fig. 1, and Fig. 3 The figure is a sectional view taken along the line - in FIG. 1, FIGS. 4A and 4B are sectional views showing the operating mode of the passage resistance adjusting valve, and FIG. 5 is a line diagram showing resistance changes in the relief passage.

The oil rotary vacuum pump 10 has a pump housing 11
An oil reservoir chamber 12 is formed inside the oil reservoir chamber 12, and a rotor cylinder 13 is arranged inside the oil reservoir chamber 12. A rotor shaft 15 is provided in the cylinder chamber 14 of the rotor cylinder 13.
A rotor 16 fixed to is rotatably housed. 17 is a bearing, and 18 is a seal member.

The vacuum pump 10 has a rotor shaft 15 and a rotor 16 arranged eccentrically with respect to the central axis of the cylinder chamber 14 as shown in FIG. 3, and a pair of vanes 19 arranged at two positions in the diametrical direction of the rotor 16. ing. A projectile body 20 is disposed between both vanes 19 in a pinched state. The rotor 16 presses both vanes 19 against the inner surface of the cylinder chamber 14 by the elastic force of the elastic body 20, and the rotor 16 moves the vanes 19 to the rotor 1.
It rotates as it moves in and out of 6 and performs a pumping action. An intake passage 21 communicates with the suction area of the cylinder chamber 14, and an intake passage 22 communicates with the exhaust area of the cylinder chamber 14. As a result, the vacuum pump 10 sucks air in, for example, a vacuum chamber connected to the intake passage 21 and discharges the sucked air into the exhaust passage 22. The air discharged into the exhaust passage 22 is discharged into the oil in the oil reservoir chamber 12 via the exhaust valve 23 and then discharged into the space above the oil level in the oil reservoir chamber 12 .

An oil supply pump 24 is disposed on the side of the rotor cylinder 13 from which the rotor shaft 15 protrudes. The oil supply pump 24 is connected to the rotor cylinder 1
A pump chamber 26 is formed inside a pump housing 25 fixed to the pump housing 3 . A rotor 27 fixed to an end of the rotor shaft 15 is rotatably housed in the pump chamber 26 .

The oil supply pump 24 has the rotor shaft 15 and the rotor 27 eccentrically arranged with respect to the central axis of the pump chamber 26 as shown in FIG. A protruding vane 28 is provided. The vane 28 is located in the pump chamber 2
The length is approximately equal to the inner diameter of No. 6. The rotor 27 rotates while moving both ends of the vane 28 into and out of the rotor 27, with both ends of the vane 28 in contact with the inner surface of the pump chamber 26, thereby performing a pumping action. An oil suction passage 29 communicates with a suction area of the pump chamber 26, and an oil supply passage 30 communicates with a discharge area of the pump chamber 26. Thereby, the oil supply pump 24 sucks oil in the oil reservoir chamber 12 connected to the oil suction passage 29 and pumps it to the oil supply passage 30 . The oil forced into the oil supply path 30 is supplied to the low-pressure side of the cylinder chamber 14 via an on-off valve 31 that is interposed in the oil supply path 30 . In addition, 24A is pump chamber 2
6 to the sealing member 18 side.

Here, the on-off valve 31 is composed of a valve body 32 and an elastic body 33 that resists the negative pressure of the cylinder chamber 14 and springs the valve body 32 in the closing direction. The on-off valve 31 opens under a condition in which the negative pressure generated in the cylinder chamber 14 overcomes the elastic force of the elastic body 33 when the vacuum pump 10 is in operation. Furthermore, when the vacuum pump 10 is stopped, the on-off valve 31 closes under a condition in which the elastic force of the elastic body 33 overcomes the negative pressure remaining in the cylinder chamber 14 .

Further, the oil supply pump 24 is provided with a relief passage 34 upstream of a portion of the oil supply path 30 where the on-off valve 31 is disposed. The relief passage 34 is provided with a passage resistance adjustment valve 35 as passage resistance adjustment means. Passage resistance adjustment valve 3
5 forms a valve seat 37 in a valve housing 36 provided at the outlet of the relief passage 34;
6 is provided with a valve body 38 and a coiled passage resistance adjuster 30. The passage resistance adjustment valve 35 is
By changing the clearance of the valve body 38 with respect to the valve seat 37, the passage resistance of the relief passage 34 can be adjusted. The passage resistance adjuster 39 is made of a shape memory alloy such as a Ti-Ni alloy, and maintains a contracted state when the oil temperature is below a certain temperature (Fig. 4A), and expands when the oil temperature exceeds a certain temperature. (Figure 4B). That is, the passage resistance adjuster 39 increases the passage resistance of the relief passage 34 during operation of the vacuum pump 10 as the oil temperature rises.

Note that 40 is a nozzle provided in the housing. The nozzle 40 is used with its nozzle diameter selected.

Next, the operation of the above embodiment will be explained.

When the vacuum pump 10 is stopped, the valve body 32 of the on-off valve 31 is closed by the elastic force of the elastic body 33 that overcomes the negative pressure remaining in the cylinder chamber 14.

When the vacuum pump 10 is operating, the oil supply pump 2
4 is driven, and the valve body 32 of the on-off valve 31 is opened by the negative pressure in the cylinder chamber 14 that overcomes the elastic force of the elastic body 33.

That is, in the case of the vacuum pump 10, the oil supply pump 24 is operated in conjunction with the operation of the vacuum pump 10.
is driven, and the oil in the oil reservoir chamber 12, which is pumped by the oil supply pump 24, is transferred to the cylinder chamber 14 via the on-off valve 31.
It will be supplied to The on-off valve 31 opens when the vacuum pump 10 is in operation and closes when the vacuum pump 10 is stopped.
Therefore, when the vacuum pump 10 is in operation, oil is always stably supplied to the cylinder chamber 14 immediately after starting. Moreover, when the vacuum pump 10 is stopped, unnecessary inflow of oil into the cylinder chamber 14 can be reliably blocked.

Additionally, if the oil temperature rises and exceeds a certain temperature during operation of the vacuum pump 10, as shown in FIG. 4B,
The passage resistance adjuster 39 is extended and the clearance of the valve body 38 with respect to the valve seat 37 is reduced to reduce the relief passage 3.
Increases the resistance of 4. The resistance change state of the relief passage 34 due to the expansion of the passage resistance adjuster 39 is as follows:
As shown in FIG. 5, the resistance is gradually increased after the oil temperature exceeds a certain temperature 01, and after reaching a certain temperature 02, the obtained maximum resistance is maintained.

Note that when the oil temperature becomes low again after the passage resistance adjuster 39 has expanded due to a rise in oil temperature, the discharge pressure of the oil supply pump 24 acts as a bias coil, and the passage resistance adjuster 39 and contract the valve body 38.
The resistance of the relief passage 34 is reduced by increasing the clearance as shown in FIG. 4B to FIG. 4A. That is, in the case of the vacuum pump 10,
As the oil temperature rises, the shape memory alloy passage resistance adjuster 39 increases the resistance of the relief passage 34, suppressing oil relief and increasing the amount of oil supplied to the cylinder chamber 14. However, even if the viscosity of the oil decreases due to a rise in oil temperature, the oil film will not break. Therefore, even if the oil temperature changes, the lubricity
It is possible to stably maintain pump performance from startup to steady operation without changing pump performance such as airtightness.

[Effect of filial plan] As described above, the present invention has the following effect when the rotor fixed to the rotor shaft is rotated in the cylinder chamber.
In a supply device for an oil rotary vacuum pump that can supply oil in an oil reservoir into a cylinder chamber, an oil supply pump that is connected to a rotor shaft and can pump oil in an oil reservoir into a cylinder chamber through an oil supply path. , an on-off valve interposed in the oil supply path, which opens due to negative pressure in the cylinder chamber when the vacuum pump is operating, and closes in response to negative pressure in the cylinder chamber when the vacuum pump is stopped; A passage resistance adjusting means includes a passage resistance adjuster made of a shape memory alloy that increases the passage resistance of the relief passage as the temperature of the oil increases as the temperature of the oil increases. It was made so that it would become so. Therefore, the oil supply state into the cylinder chamber is stabilized,
Even if the oil temperature changes, it is possible to stably maintain pump performance such as lubricity and airtightness.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the main parts of an oil rotary vacuum pump to which the present invention is applied, Fig. 2 is a partially cutaway view taken along the - line in Fig. 1, and Fig. 1
4A and 4B are sectional views showing the operating mode of the passage resistance adjusting valve, and FIG. 5 is a line diagram showing resistance changes in the relief passage. 10... Oil rotary vacuum pump, 12... Oil reservoir chamber, 14...
Cylinder chamber, 15... Rotor shaft, 16... Rotor, 2
4... Oil supply pump, 31... Opening/closing valve, 34... Relief passage, 35... Passage resistance adjustment valve, 39... Passage resistance adjuster.

Claims (1)

[Scope of utility model registration request] In an oil supply device for an oil rotary vacuum pump that can supply oil from an oil reservoir into a cylinder chamber while a rotor fixed to the rotor shaft is rotating in the cylinder chamber, the An oil supply pump that can pump oil into the cylinder chamber through an oil supply path, and an oil supply pump that is interposed in the oil supply path and opens by the negative pressure in the cylinder chamber when the vacuum pump is operating, and is opened by the negative pressure in the cylinder chamber when the vacuum pump is stopped. A relief passage is formed by branching from the upstream side of the oil supply path with respect to the opening/closing valve installation part.
A oil supply device for an oil rotary vacuum pump, comprising: passage resistance adjusting means including a passage resistance adjuster made of a shape memory alloy that increases the passage resistance of a relief passage as the temperature of oil rises.