JPS643832Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in scroll-type fluid machines that are used, for example, in air compressors, pumps, blowers, etc., and are capable of easily controlling no-load operation.

Conventionally, there has been a scroll type in which a fixed scroll having a wrap portion formed by an involute or a curve close to an involute and an orbiting scroll are overlapped with each other with the wrap portion inside, and the orbiting scroll is rotated so as not to apparently rotate relative to the fixed scroll. Fluid machines are known.

When this scroll-type fluid machine is used as an air compressor, the air sucked in from the suction port is sealed in the sealed space formed between the fixed scroll and the orbiting scroll, and as the orbiting scroll revolves, the sealed space is reduced. The structure is such that the compressed air is compressed by the scroll, and the compressed air is discharged from a discharge port formed in the center of the fixed scroll. When the air compressor mentioned above is operated with no load (unload operation), a method is used in which compressed air is not discharged from the discharge port by throttling the suction port and making the suction pressure negative. ing.

However, in the no-load operation method according to the conventional technology described above, the pressure in the closed space that becomes the pressurized chamber decreases, and the difference that acts between the side surface of the anti-lap part of the orbiting scroll, where atmospheric pressure acts, and the side surface of the closed space. The pressure increases the sliding surface pressure between the orbiting scroll and the fixed scroll. As a result, a galling phenomenon or a seizure phenomenon occurs on the sliding surface, which not only shortens the service life but also causes a decrease in compression efficiency during load operation. On the other hand, since the pressure balance between the orbiting scroll and the fixed scroll is disrupted, the drive shaft and crankshaft swing and rotate, resulting in uneven bearing wear. Furthermore, in order to eliminate the above-mentioned drawbacks, the amount of lubricating oil supplied must be significantly increased during no-load operation.

The present invention improves the drawbacks of the scroll-type fluid machines according to the prior art, and creates a sealed chamber that becomes a pressurized chamber by displacing the fixed scroll in the axial direction with respect to the casing when the inside of the pressure vessel reaches a predetermined pressure. It is an object of the present invention to provide a scroll type fluid machine configured so that all spaces are communicated with each other so that complete no-load operation can be performed.

In order to achieve this object, the present invention includes: a drive shaft rotatably supported with respect to a casing and having a crankshaft at its tip; an orbiting scroll rotatably supported by the crankshaft and having a lap part; , a fixed scroll having a lap portion that overlaps the wrap portion of the orbiting scroll with a predetermined angle shift and being slidable in the axial direction with respect to the casing; A pressurizing chamber is formed between each lap part, and a side surface of the opposite wrap part of the fixed scroll and the casing, and the fixed scroll is pressed against the fixed scroll and the orbiting scroll during load operation. a chamber for storing pressurized fluid discharged from the pressure chamber as back pressure through a discharge port provided in the scroll; and a chamber located within the chamber and stretched between the casing and the orbiting scroll, and the fixed A compression spring having a spring force slightly stronger than supporting the scroll's own weight and normally urging the fixed scroll toward the orbiting scroll, and a check valve connected to the chamber to store pressurized fluid. A pressure vessel is connected to the chamber, and when the pressure in the pressure vessel exceeds a set pressure, the back pressure in the chamber is released, and the pressure in the pressurization chamber is used to fix the pressure against the compression spring. It consists of a relief valve that separates the scroll from the orbiting scroll in the axial direction and allows the scroll to enter a no-load operating state.

With this configuration, when the pressure inside the pressure vessel is below the set pressure, the interior of the chamber is in a predetermined pressurized state, so the back pressure and compression spring acting on the side opposite to the wrap of the fixed scroll, The fixed scroll is pressed and compression operation can be performed. On the other hand, if the pressure inside the pressure vessel exceeds the set pressure,
When the relief valve opens and the room is communicated with the atmosphere, the fixed scroll is pushed away from the orbiting scroll by the pressure inside the pressurized chamber against the compression spring, and the entire pressurized chamber is is connected and enters a no-load operation state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a first embodiment of the present invention, in which a casing 1 includes a bearing portion 1A and a cylindrical portion 1B.
and a lid portion 1C are formed, and a lid member 2 is fixedly provided at the tip of the cylindrical portion 1B. 3 is the lid part 1
A drive shaft is provided through C, and a crankshaft 4 is provided integrally with the drive shaft 3, and the axial center of the drive shaft 3 and the axial center of the crankshaft 4 are eccentric by a distance δ. . The drive shaft 3 is supported by a bearing portion 1A of the casing 1 by a bearing 5 such as an angular ball bearing. Here, the outer ring of the bearing 5 is press-fitted into the bearing portion 1A, and the inner ring is press-fitted into the drive shaft 3, so that the drive shaft 3 is attached to the casing 1 so that it cannot be displaced in the axial direction and the radial direction. It is being Note that the bearing 5 is configured as a front-to-front combination bearing or a back-to-back combination bearing as shown in the figure,
The bearing 5 is filled with lubricating oil.

Reference numeral 6 indicates an orbiting scroll provided on the same axis as the crankshaft 4, and the orbiting scroll 6 has an end plate 6.
A, a wrap portion 6B erected on the mirror plate 6A,
It consists of a bearing part 6C formed on the side opposite to the lap of the end plate 6A, and the lap part 6B is formed in an involute or a curve close to an involute (see FIG. 2). Similarly to the bearing 5, the crankshaft 4 is supported by a bearing 7 such as an angular ball bearing. Here, the outer ring of the bearing 7 is press-fitted into the bearing hole 6C of the orbiting scroll 6, and the inner ring is press-fitted into the crankshaft 4, so that the orbiting scroll 6 is moved axially and radially with respect to the crankshaft 4. Mounted so that it cannot be displaced.

Further, one or more key grooves 8 are formed in the inner peripheral surface of the cylindrical portion 1B of the casing 1, and a fixed scroll 9 is provided in the casing 1 so as to be slidable in the axial direction while being guided by the key grooves 8. is provided. The fixed scroll 9 includes an end plate 9A, a lap portion 9B erected on the end plate 9A, and a protrusion 9C that fits into the keyway 8. The wrap portion 9B is formed into an involute or a curve close to an involute, and the wrap portion 9B is formed in the shape of an involute or a curve close to an involute.
When the orbiting scroll 6 rotates, each of the lap parts 6B and 9B creates a plurality of pressurizing chambers 1.
0,10 are formed. A half-moon-shaped suction port 11 is formed at the end of the wrap portion 9B (see FIG. 2), and a discharge port 12 is formed at the center of the end plate 9A.

A chamber 13 is formed between the side surface of the fixed scroll 9 opposite to the lap and the lid member 2, a discharge port 12 is opened in the chamber 13, and a plurality of compression springs 14, 14 are installed in the chamber 13. is stretched, and the fixed scroll 9 is biased to the left in FIG. 1 by the spring 14. Here, the compression spring 14 is fixed scroll 9
A spring is used that is slightly stronger than it can support its own weight.

Furthermore, 15 is an auxiliary crank provided between the casing 1 and the orbiting scroll 6, and the auxiliary crank 15 is shifted in position as shown in FIG.
There are several. In the auxiliary crank 15, the axes of the shaft 15A on the casing 1 side and the shaft 15B on the orbiting scroll 7 side are eccentric by a distance δ,
Each of the shafts 15A, 15B is supported by, for example, a needle bearing. Therefore, when the drive shaft 3 rotates, the orbiting scroll 6 is rotated by the auxiliary crank 15.
The fixed scroll 9 revolves around the axis of the fixed scroll 9 with a radius δ.

Next, 16 is a pipe connected to the chamber 13, this pipe 16 branches into pipes 17 and 18, and one pipe 1
7 is connected to a pressure vessel 19, and a check valve 20 is provided in the middle of the pipe 17 to allow pressurized fluid to flow only to the pressure vessel 19. The other pipe 18 is connected to a relief valve 21 which is an air pilot type spring return type two-position switching valve, and as shown in FIG. 1, the relief valve 21 is normally in a position that closes the pipe 18. Pilot portion 21 of the relief valve 21
A is connected to the pressure vessel 19 via piping 22,
A pilot valve 23 is provided in the middle of the pipe 22. The pilot valve 23 includes a valve body 23B that is seated on and off the valve seat 23A, and a pressure setting spring 23C that sets the opening pressure of the valve body 23B and normally seats the valve body 23B on the valve seat 23A. It is configured. Note that the pressure vessel 19 is provided with a stop valve 24 and is connected to air-using equipment via the stop valve 24.

In the scroll fluid machine configured as described above, in the initial state where the motor (not shown) is not started, the fixed scroll 9 is urged toward the orbiting scroll 6 by the compression spring 14, and the full pressure is applied. The chamber 10 is in a non-communicating state and the compression operation can be started. Therefore, when the motor is rotated, the rotation is caused by the drive shaft 3, the crankshaft 4, and the bearing 7.
It is transmitted to the orbiting scroll 6 via. The axial center of the orbiting scroll 6 is coaxial with the crankshaft 4, the axial center of the fixed scroll 9 is coaxial with the drive shaft 3, and both axes are eccentric by a distance δ, and the axial center of the auxiliary crank 15 is eccentric. Since the shafts 15A and 15B are also eccentric by a distance δ, the orbiting scroll 6 performs a circular motion relative to the fixed scroll 9. The air sucked in through the suction port 11 is gradually compressed within the pressurizing chamber 10 and is discharged into the chamber 13 through the discharge port 12.

At this time, the moment force acting on the orbiting scroll 6 by the compressed air in the pressure chamber 10 is transmitted as torque to the auxiliary crank 15, and the pushing force in the axial and radial directions is applied to the crankshaft 4 via the bearing 7. It is further transmitted from the drive shaft 3 to the casing 1 via the bearing 5.

Next, the compressed air from the chamber 13 is transferred to the pipes 16, 1
7. It is stored in the pressure vessel 19 via the check valve 20 and is sent to the relief valve 21 via the pipes 16 and 18. However, since the relief valve 21 is in the closed state as shown, compressed air is sent only to the pressure vessel 19.

When the amount of compressed air used by the air-using equipment connected to the stop valve 24 is large and the pressure inside the pressure vessel 19 is lower than the set pressure set on the spring 23C of the pilot valve 23, the fixed scroll 9 The protrusion 9C is guided to the keyway 8 and pushed to the left in the figure by the back pressure of the chamber 13 and the spring 14 acting on the side surface of the anti-lap portion. For this reason, the pressurizing chamber 10
becomes a closed space, compresses the air from the suction port 11, and performs normal load operation.

However, when the pressure inside the pressure vessel 19 increases,
The pressure acts on the valve body 23B of the pilot valve 23 through the pipe 22, and opens the valve body 23B against the force of the spring 23C. As a result, the compressed air is released from the relief valve 2.
1, and the relief valve 21
is switched to the atmosphere communication position, and the compressed air in the chamber 13 is released to the atmosphere and becomes low pressure.

When the air sucked in from the suction port 11 is compressed in the pressurizing chamber 10 in this state, the fixed scroll 9 is pressed to the right in the figure against the compression spring 14, that is, in the direction away from the orbiting scroll 6, a gap is formed between the lap parts 6B and 9B, and the pressurized chambers 10 are all in a communicating state. Compression function deteriorates rapidly. In other words, it becomes a no-load operating state.

When the amount of compressed air used increases and the pressure inside the pressure vessel 19 decreases, the pilot valve 23
C, the valve body 23B closes and the relief valve 21 is switched to the position shown in the figure. As a result, the pressure inside the chamber 13 gradually increases due to the compressed air discharged from the pressurizing chamber 10, and the fixed scroll 9 is displaced to the left in the figure by the back pressure inside the chamber 13 and the spring 14. , resume normal load operation.

Next, FIG. 3 shows a second embodiment of the present invention,
Components that are the same as those in the first embodiment are given the same reference numerals. In the figure, reference numeral 31 indicates a relief valve consisting of an electromagnetic pilot spring return type two-position switching valve. A pilot portion 31A of the relief valve 31 is electrically connected to a pressure switch 32, and the pressure switch 32 It is connected to the pressure vessel 19 via. Then, the pressure switch 32 issues a pilot signal when the pressure inside the pressure vessel 19 reaches a predetermined set pressure.

The present embodiment is configured as described above, but the pressure inside the pressure vessel 19 gradually increases and the pressure switch 19 is activated.
When turned ON, a pilot signal is transmitted to excite the pilot portion 31A of the relief valve 31 and switch it to the atmosphere communication position. As a result, the fixed scroll 9 is displaced to the right in the figure while the protrusion 9C is guided by the keyway 8, resulting in a no-load operating state.

When the pressure inside the pressure vessel 19 decreases, the pressure switch 32 is turned OFF and the relief valve 31 is switched to the position shown in the figure again, and the fixed scroll 9 is again pushed to the left in the figure as in the first embodiment described above. and restarts load operation.

The scroll type fluid machine according to the present invention has been described in detail above, and has the following effects.

Since the pressure in the pressure vessel is detected, the fixed scroll is slid in the axial direction, and the gap between the fixed scroll and the orbiting scroll is used to perform no-load operation, the no-load operation can be controlled reliably. be able to.

During no-load operation, the end plate sliding surfaces of the fixed scroll and the orbiting scroll are separated from each other, so that unreasonable surface pressure is not applied to the end plate sliding surfaces as in the prior art, and galling and seizure phenomena can be prevented.

During no-load operation, the pressure relationship between the front and rear of the orbiting scroll and the fixed scroll is balanced at approximately atmospheric pressure, so operation can be continued with the same pressure balance as during load operation.

The bearing provided between the orbiting scroll and the crankshaft receives all the loads acting on the orbiting scroll in the axial and radial directions, and the orbiting scroll and fixed scroll are kept in contact with each other even during no-load operation. Since it can be configured, it is easy to apply to oil-free fluid machines.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of a scroll-type fluid machine according to the present invention, FIG. 1 is a partially sectional system diagram, and FIG. 2 is in the direction indicated by the − arrow in FIG. 1. The sectional view and FIG. 3 are also partial system diagrams showing the second embodiment. 1... Casing, 3... Drive shaft, 4... Crankshaft, 6... Orbiting scroll, 8... Keyway,
9... Fixed scroll, 10... Pressurized chamber, 11...
...Suction port, 12...Discharge port, 13...Chamber, 15...
... Auxiliary crank, 19 ... Pressure vessel, 20 ... Check valve, 21, 31 ... Relief valve, 23 ... Pilot valve, 32 ... Pressure switch.

Claims (1)

[Scope of utility model registration request] a drive shaft that is rotatably supported with respect to the casing and has a crankshaft at its tip; an orbiting scroll that is rotatably supported by the crankshaft and has a lap portion; a fixed scroll having overlapping lap parts and slidable in the axial direction with respect to the casing; and a pressurized chamber formed between each lap part while the orbiting scroll revolves with respect to the fixed scroll. is formed between the side surface of the anti-lap part of the fixed scroll and the casing, and during load operation, the pressure is applied via a discharge port provided in the fixed scroll in order to press the fixed scroll toward the orbiting scroll. A chamber for storing pressurized fluid discharged from the pressure chamber as back pressure; a compression spring that normally biases the fixed scroll toward the orbiting scroll; a pressure vessel connected to the chamber via a check valve to store pressurized fluid; When the pressure in the container exceeds the set pressure, the back pressure in the chamber is released, and the pressure in the pressurized chamber moves the fixed scroll away from the orbiting scroll in the axial direction against the compression spring, and the A scroll-type fluid machine consisting of a relief valve that allows it to enter a loaded operating state.