JPS6115275Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a dry screw machine.

In general, a dry screw machine, such as a screw compressor, houses two rotors that mesh with each other in a non-contact state and rotate in a casing that has two parallel cylindrical holes that partially overlap each other in a cross section perpendicular to the axis. The suction side and the discharge side of the two rotors are each supported by the casing via bearings.

By the way, in this type of equipment, since the pressure on the suction side is low, it is possible to use a grease-filled bearing on the suction side, but in this case, the temperature rises due to heat conduction from the casing, and the grease leaks, causing lubrication. It has the disadvantage of causing defects. On the other hand, it is also possible to provide a splash lubrication bearing on the suction side, but even in this case, there is a drawback that lubricity is impaired due to overheating of the bearing.

Therefore, the present invention was developed to solve the above-mentioned drawbacks, and in order to secure the suction volume for cooling the bearing, the suction gas is sucked in from the radial direction of the rotor. For this reason, in the present invention, a passage is formed along the bearing that communicates with the suction port, and this passage communicates the cooling passage with the cylindrical hole in which the rotor is located, thereby promoting the introduction of suction gas. The purpose of the present invention is to provide a dry type screw machine that can simply dry-cool a bearing and prevent overheating.

In order to achieve the above object, the present invention accommodates two meshing rotors in a cylindrical hole in a casing, supports the shaft part of the rotor by a bearing, and extends radially from the bearing on the suction side to the rotor side. A suction port is formed in the casing of the rotor so as to close before the interdental volume of both rotors reaches its maximum, the suction port is communicated with a passage along the bearing, one end of the cooling passage is opened in the passage, and the other end is opened. The opening is made into a cylindrical hole near the position of both rotors where the interdental volume of both rotors is maximum.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIGS. 1 and 2, 1 is a casing of a dry screw compressor, and the casing 1 is a main body provided with two parallel cylindrical holes 2A and 2B that partially overlap each other in cross section perpendicular to the axis. part 2, and cover parts 3 and 4 attached to both ends of the main body part 2.
and cap parts 5, 6 attached to cover parts 3, 4.

Inside the two cylindrical holes 2A and 2B of the main body part 2,
Two rotors 7 and 8 are housed therein, which rotate while meshing with each other in a non-contact state, and shaft portions 7A and 7B at both ends of the male rotor 7 are supported by cover portions 3 and 4 via bearings 9 and 10, respectively. ing. here,
The suction side bearing 9 is a grease-filled bearing.
Although not shown, the female rotor 8 is similarly supported by the cover parts 3 and 4 via bearings. A suction side bearing 7A of the male rotor 7 protrudes outside the casing 1 and is connected to a drive source. On the other hand, a timing gear 11 is attached to the discharge side shaft portion 7B of the male rotor 7, and a cover 4
A chamber 12 surrounded by a cap 6 and a cap 6 contains lubricating and cooling oil. 13 is a shaft sealing device.

A suction port 14 and a discharge port 15 are formed in the main body portion 2 of the casing 1 . The suction port 14 opens into the cylindrical holes 2A, 2B so as to be closed before the interdental volume of both the rotors 7, 8 reaches its maximum. To explain this with reference to FIG. 3, FIG. 3 shows a developed state of the outer circumferences of both rotors 7 and 8 and the inner circumferential surfaces of the cylindrical holes 2A and B. In this figure, the rotor tooth tip line 16, 17 and rotor tooth tip line 1
The area surrounded by 8 and 19 indicates the area where the interdental volume is maximum, and the dotted area indicates the area where the suction port 14 is open. That is, here, the space between the rotor teeth becomes a sealed space at the positions of the rotor tooth tip lines 20 and 21, and compression is performed toward the discharge port 15 side. Note that the discharge port 15 opens at the rotor tooth tip lines 22, 23'.

In FIG. 1, reference numeral 23 denotes a suction side bearing cooling passage for cooling the suction side bearing 9. In order to promote the introduction of suction gas from the suction port 14 by the rotation of the rotors 7 and 8, a cooling passage 23 is used to cool the suction side bearing 9. One end 23A of the passage 23 communicates with the suction port 14 via a passage 24 along the suction side bearing 9, and the other end 23B is in the vicinity of the position where the rotor interdental volume is maximum, that is, in this case, the rotor tooth tip line. It opens into the cylindrical hole 2A of the casing 1 near the hole 18.

In the above embodiment, when the rotors 7 and 8 are rotated, the volume between the rotor teeth changes from the suction side to the discharge side as shown in FIG. Here, the space between the rotor teeth is closed to the suction port 14 at a position where the volume is indicated by Vs in the figure. At this time, since the cooling passage 23 communicates with the suction port 14 via the passage 24, the suction gas flows from the suction port 14 to the passage 2 from the position Vs to the maximum volume Vmax.
4 and the cooling passage 23, and is sucked between the teeth of the rotor. Therefore, the suction stroke is performed without any trouble, and the suction side bearing 9 is effectively cooled.

When the rotor interdental volume reaches the maximum volume Vmax,
Since the opening 23B of the cooling passage 23 is closed, the suction gas is then compressed. When the discharge amount and the amount of gas used are the same amount, the pressure changes as shown in FIG. 4 with respect to the rotor rotation angle. That is,
While the volume reaches Vd from Vs through Vmax, the pressure rises from atmospheric pressure Ps to Pd and is discharged.

Although one embodiment has been described above, the present invention is not limited to the above embodiment, and includes, for example, the following modifications.

While the conventional suction port opening position is at the rotor tooth tip lines 16 and 18 in FIG. 3, in the above embodiment, the opening position is at the rotor tooth tip line 20 and 21, that is, a position delayed by one tooth. However, the delay is not limited to this, and may be a delay of 1.5 teeth, 0.5 teeth, etc.

The suction side bearing may be a splash oil supply bearing, and in this case, the cooling passage 23 may be formed to cool the lubricating oil of this bearing.

The present invention can be applied to dry screw machines other than screw compressors.

As is clear from the above description, the present invention forms a suction port in the casing so that it is closed before the interdental volume of both rotors reaches its maximum, and closes the suction port near the position where the interdental volume of both rotors reaches its maximum. Since the cylindrical hole of the casing is characterized by opening a passage for cooling the suction side bearing, the suction side bearing can efficiently take in suction gas from the radial direction of the rotor. The bearing is effectively cooled, and overheating due to heat in the casing is prevented. Therefore, it is possible to ensure the life of the suction side bearing. Furthermore, since the cooling performance of the suction side bearing portion is improved, it becomes easier to employ a grease-filled bearing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view taken along line B-B in FIG. 2, showing an embodiment in which the present invention is applied to a dry screw compressor. FIG. 2 is a sectional view taken along line A-A in FIG. 1. FIG. 3 is a developed view of the outer periphery of the two rotors and the inner periphery of the cylindrical hole of the casing shown in FIG. 2; Figure 4 is the first
FIG. 3 is a diagram showing the relationship between the rotor rotation angle, the rotor interdental volume, and the pressure in the illustrated embodiment. 1... Casing, 2A, 2B... Cylindrical hole,
7, 8...Rotor, 14...Suction port, 23...
...Suction side bearing cooling passage.

Claims (1)

[Scope of utility model registration request] Two rotors that mesh and rotate without contacting each other are accommodated in a casing having two parallel cylindrical holes that partially overlap each other in a cross section perpendicular to the axis, and both ends of the shaft portions of the rotors are connected to bearings. A suction port is provided in the casing located on the rotor side and radially from one of the two bearings, and air is supplied from the radial direction of both rotors through the suction port. In the dry screw machine, a suction port is formed in the casing so as to close before the interdental volume of both the rotors reaches a maximum, and a suction port is formed between the bearing and the casing, and the suction port is connected to the suction port and the bearing is connected to the suction port. A cooling passage is provided in the passage along which one end is open and the other end is opened in the cylindrical hole near the position of the rotor where the interdental volume of both rotors is maximum. Characteristic dry screw machine.