[0045] Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, the same parts are given the same reference numerals, and repetitive descriptions are omitted.
[0046] Figure 4 It is a partial cross-sectional view of the gear-driven turbo compressor provided by the present invention corresponding to FIG. 1B. In this figure, the gear-driven turbo compressor 10 of the present invention has a large gear 12, a small gear 14, an impeller 16, a thrust ring 18, and a thrust bearing 20.
[0047] In this figure, the gear-driven turbo compressor 10 of the present invention is a four-stage compressor, but the present invention is not limited to this. It can be a single-stage compressor, or a compressor of 2, 3, or 5 stages or more. machine.
[0048] The large gear 12 is driven by an unillustrated external drive device (motor, engine, or turbine) to rotate around the shaft center of the large gear shaft 11. The large gear 12 is preferably a spur gear, a helical gear or a herringbone gear with about 10 times more teeth than the small gear 14 in order to increase the speed of the small gear 14, but the present invention is not limited by this, as long as it has a speed increasing function, it can be used It is other gears.
[0049] The small gear 14 meshes with the large gear 12 and rotates at a high speed with the shaft center of the pinion shaft 13 as the center. Only one pinion gear 14 is shown on the left side of the figure, but for a 4-stage compressor, it is better to provide other pinion gears on the right side of the figure.
[0050] The impeller 16 is fixed on the pinion shaft 13 and rotates at a high speed around its axis. In this example, the impeller 16 is provided at both ends of the pinion shaft 13, but it may be provided at only one end. In addition, the casing (compressor casing) surrounding the impeller and the gas flow path are omitted in this figure.
[0051] The thrust ring 18 is fixed around the pinion shaft 13, supports the side surface of the large gear 12 in a slidable manner, and transmits the axial force of the pinion shaft 13 to the large gear 12. In this example, the thrust ring 18 clamps the teeth of the large gear 12 in the axial direction, but when the impeller 16 is only provided at one end of the pinion shaft 13, a thrust ring 18 can also be provided to bear Its axial force.
[0052] As for the gap between the thrust ring 18 and the tooth portion of the large gear 12, as long as it can slide with low resistance with lubricating oil, it is set to a sufficiently small gap (for example, 0.1 to 0.2 mm).
[0053] The thrust bearing 20 bears the axial force acting on the large gear shaft 11. In this example, the thrust bearing 20 can also bear the radial force acting on the large gear shaft 11, but the present invention is not limited by this.
[0054] Figure 4 Among them, 22 is a radial bearing that receives the radial force of the pinion shaft 16. The radial bearing 22 is preferably a sliding bearing, to which lubricating oil is supplied through a circulation path not shown.
[0055] In addition, 23 is a gas seal, which makes it difficult for the gas pressurized by the impeller 16 to flow to the outside of the casing. The gas seal 23 may adopt a labyrinth seal, a dry gas seal, an oil film seal, a mechanical seal, and the like.
[0056] Figure 4 Among them, the gear-driven turbo compressor 10 of the present invention also has an axial movement limiter 30. The axial movement limiter 30 can limit the movement amount of the pinion shaft 13 supported by the thrust bearing 20 when the pinion shaft 13 moves in the axial direction beyond a predetermined threshold a. This situation occurs when the thrust bearing 20 is excessively worn or the thrust ring fails (falling off, etc.).
[0057] In this figure, the axial movement limiter 30 is mounted on the inner side of the gear box 15 containing the large gear 12 and the small gear 14, and has an outer surface located from the thrust ring 18 (in this example, the auxiliary thrust ring 17 The outer surface) is a sliding surface (31 to be described later) at a position separated by a predetermined threshold a (not shown).
[0058] The auxiliary thrust ring 17 is not indispensable, and may be integrally formed with the thrust ring 18.
[0059] The predetermined threshold a is preferably set in accordance with the requirement to substantially avoid excessive contact between the impeller 16 and the casing (not shown).
[0060] The gear-driven turbo compressor 10 of the present invention also has a non-contact distance sensor 24 that measures the axial movement of the large gear shaft 11 (in this example, the large gear 12). The non-contact distance sensor 24 is a magnetic sensor, an eddy current sensor, an electrostatic capacitance sensor, an optical sensor, etc., capable of detecting the axial movement of the large gear shaft 11 or the large gear 12 in a non-contact manner.
[0061] The output of the non-contact distance sensor 24 is input to a control device through a control circuit not shown. The control device always monitors the axial movement of the large gear shaft 11 and stops the compressor when an excessive axial movement occurs.
[0062] According to the above configuration of the present invention, the pinion shaft 13 supported by the thrust bearing 20 of the large pinion shaft 11 is provided with the axial movement limiter 30 which limits the axial movement amount when the pinion shaft 13 supported by the thrust bearing 20 of the large gear shaft 11 moves beyond the predetermined threshold a. Therefore, during normal operation, the thrust bearing 20 of the large gear shaft 11 makes the axial movement of the pinion shaft 13 below the predetermined threshold a, and the axial movement limiter 30 does not work, only when the predetermined threshold a is exceeded. When the axial movement is too large, it works and restricts its axial movement.
[0063] Therefore, when the large gear shaft 11 undergoes excessive axial movement, it is possible to basically avoid excessive contact between the impeller 16 and the casing.
[0064] Figure 5A , Figure 5B It is a drawing showing a specific example of the axial movement limiter 30 of the present invention, Figure 5A Is a cross-sectional view, Figure 5B It is its B-B cross-sectional view.
[0065] As shown in the figure, the axial movement limiter 30 is a hollow ring-shaped member that can be divided into two parts up and down, and is installed on the circular through-hole of the radial bearing 22 for receiving the radial force of the pinion shaft 13 In the hole.
[0066] In addition, the axial movement limiter 30 has a through hole 32 under which the lubricating oil discharged from the radial bearing 22 passes.
[0067] The sliding surface 31 of the axial movement limiter 30 is cast with white metal to reduce the resistance during sliding. As long as it is a bearing material or coating material used for a sliding bearing with good compatibility, other materials may be used for the sliding surface 31. In addition, as for the sliding surface 31, the base material of the axial movement limiter 30 may be surface-hardened, or the base material may not be treated.
[0068] The axial movement limiter 30 is provided at a position capable of supporting the pinion shaft 13 (more directly, the auxiliary thrust ring 17) of the gear box.
[0069] In addition, in order to facilitate the adjustment processing of the axial movement limiter 30 when the axial position of the sliding surface 31 of the axial movement limiter 30 needs to be fine-tuned, it is made to be able to be easily removed from the gear box 15 Removed and installed structure. That is, the mounting structure of the axial movement limiter 30 is to insert the axial movement limiter 30 into the groove of the gear box. In this case, it is better to fit the upper half of the axial movement limiter 30 into the groove of the upper gear box, and fix the slit portion 33 to the upper gear box.
[0070] In addition, the axial movement limiter 30 also plays a role in preventing the oil discharged from the bearing from splashing into the gear box.
[0071] The installation of the axial movement limiter 30 can also be fastened with bolts without being inserted into the groove. In addition, the axial movement limiter 30 may be provided on the large gear shaft 11.
[0072] According to the above configuration, during normal operation, the axial clearance between the axial movement limiter 30 and the thrust ring 18 (or the auxiliary thrust ring 17) can be guaranteed, but if the pinion shaft 13 moves axially, then The gap is reduced. Therefore, when the axial movement reaches an excessively large value, the gap will become zero, and the sliding surface 31 of the axial movement limiter 30 is in contact with the outer surface of the thrust ring 18 (or auxiliary thrust ring 17) to limit The occurrence of greater axial movement.
[0073] Of course, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope not departing from the gist of the present invention.
