JPH0647100U - Helicopter blade mounting structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the strength of bearings against thrust load due to centrifugal force. Prevent insufficient bearing lubrication due to grease scattering. [Structure] A plurality of angular contact ball bearings 21 are mounted in series on the inner peripheral surface of a hub grip 7 fitted with a shaft 2 to disperse and handle a thrust load. The O-ring 32 is attached to the outer peripheral surface of the bearing holding ring 15 attached to the end surface of the shaft 2 so that the grease of the bearing does not scatter. The grip cup 34 is attached to the outer peripheral surface of the hub grip 7 so that the grease of the plurality of bearings 21 is not biased toward the outer bearing and the inner bearing is insufficiently lubricated due to the centrifugal force.
From there, it is desirable to supply the grease 33 to the inner end of the inner angular ball bearing 21 through the grease passage 35 penetrating the peripheral wall of the hub grip 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a helicopter blade mounting structure, and more particularly to improving durability against a thrust load due to centrifugal force.

[0002]

[Prior art]

 A conventional mounting structure of this type will be described with reference to FIG. One end of a plurality of shafts 2 is attached to a rotating shaft 1 of the helicopter by a mounting member 3 at right angles to the axial direction of the rotating shafts, and the other ends of the shafts 2 (only one is shown in the figure). One end of a cylindrical hub grip 7 is fitted around each of the parts via radial ball bearings 4 and 5 and a thrust ball bearing 6, and the blade is attached to the inner peripheral surface of the other end of the hub grip 7. The bases of the (blades) 8 are fitted together and fixed to each other by the bolt 9 and the nut 10.

The radial ball bearings 4 and 5 resist the load due to gravity acting in the radial direction around the axis of the hub grip 7, and the thrust ball bearing 6 resists the thrust load 13 due to the centrifugal force. Each of the hub grips 7 allows the hub grip 7 to rotate around the shaft 2 in the circumferential direction. The thrust load 13 due to the centrifugal force acts on the corner portion of the thrust ball bearing 6 from the step portion 7 a formed on the inner surface of the hub grip 7.

The rotation of the hub grip 7 is necessary to twist the blade 8 and change its posture. The radial ball bearing 5 and the thrust ball bearing 6 are fitted to the other end of the shaft 2, and a bearing retaining ring 15 is fixed to the end surface of the shaft 2 with bolts 14 to prevent the shaft from coming off. The mounting member 3 is fixed to the peripheral surface of the large-diameter front end portion of the rotating shaft 1 by a bolt (not shown) while being engaged with the shaft 2.

[0005]

In the conventional blade mounting structure, the thrust load 13 due to the centrifugal force is received by one thrust ball bearing 6. Recently, however, the overall mounting structure including the bearings has been made smaller and lighter, but the thrust ball bearings have a new problem of insufficient strength.

In addition, due to centrifugal force during rotation, the grease held in the bearing is moved in the direction of centrifugal force, and eventually it scatters, resulting in insufficient lubrication, which may result in insufficient durability. there were. A first object of the present invention is to improve the strength of the bearing against a thrust load due to the centrifugal force, and a second object thereof is to prevent insufficient durability of the bearing due to insufficient lubrication.

[0007]

[Means for Solving the Problems]

 (1) One end of a plurality of shafts is attached to the rotating shaft of a helicopter at right angles to the axial direction of the rotating shaft, and one end of a cylindrical hub grip is mounted around the other end of the shafts through a bearing. In a blade mounting structure of a helicopter, which is fitted into each other, and a base of a blade is fitted and fixed to an inner peripheral surface of the other end of the hub grip, the invention of claim 1 provides a plurality of angular balls as the bearing. Bearings are mounted in series on the inner peripheral surface of the hub grip.

(2) According to a second aspect of the invention, in the blade mounting structure for a helicopter according to the first aspect, an O-ring is provided on the outer peripheral surface of a bearing retaining ring attached to the other end surface of the shaft. It is attached so as to contact the inner surface of the grip. (3) In the invention of claim 3, in the blade mounting structure of the helicopter according to (1) or (2), a grease cup is attached to the outer peripheral surface of the hub grip, and the grease contained in the grease cup is attached. Supplying to the bearing through a grease passage extending through the peripheral wall of the hub grip.

[0009]

Embodiment An embodiment of the present invention is shown in FIGS. 1 and 2 in which parts corresponding to those in FIG. In this invention, instead of the conventional radial ball bearing 5 and thrust ball bearing 6, a plurality (four in the example in the figure) of angular ball bearings 21 are mounted in series on the inner peripheral surface of the hub grip 7. The angular contact ball bearing 21 is a bearing capable of simultaneously bearing a radial load due to gravity and a thrust direction centrifugal force (direction in which the centrifugal force acts on the blade 8 etc. due to rotation of the rotating shaft 1) due to centrifugal force. As shown in detail in FIG. 2, the balls 24 are sandwiched between the spherical inner surfaces of the inner race 22 and the outer race 23. The thrust load 13 is sequentially transmitted from the outer end surface of the ring-shaped flange 36 formed on the inner peripheral surface of the hub grip 7 to each outer race 23 of the plurality of angular ball bearings 21, and as shown by a load action line 25. The outer race 23, the ball 24, and the inner race 22 act on the common shaft 2. As described above, the thrust load 13 due to the centrifugal force is dispersed by the plural angular ball bearings 21, which are responsible for each, and finally collected on the common shaft 2. Therefore, the force acting on each angular contact ball bearing 21 is reduced to 1 / n (n is the number of bearings in series) as compared with the case where only one bearing is used, and the durability is improved.

Further, in order to prevent the grease retained in the bearing from scattering due to centrifugal force, an O-ring 32 for sealing is embedded in the outer peripheral surface of the bearing restraining ring 15, and the inner periphery of the hub grip 7 is Mounted to face. In this example, the grease held by the plurality of angular contact ball bearings 21 is further offset by centrifugal force to the outer side, that is, the bearing on the side of the retaining ring 15, and the inner side, that is, the bearing on the side of the rotating shaft 1 causes insufficient lubrication. In order to replenish the grease, a grease cup 34 filled with grease 33 is attached to the outer peripheral surface of the hub grip 7, and the grease 33 is passed through a grease passage 35 penetrating the peripheral wall of the hub grip 7 to provide the inner angular ball bearing 21. Is supplied to the end face of. The grease passage 35 is formed in a ring-shaped flange 36 on the inner peripheral surface of the hub grip 7, and supplies grease to a grease reservoir 37 between the inner peripheral surface of the flange 36 and the peripheral surface of the shaft 2. The grease 33 is gradually replenished from the inner bearing to the outer bearing by centrifugal force.

In this example, the radial ball bearing 4 is fitted to the inner peripheral surface of the hub grip 7 on the side of the rotary shaft 1 in the same manner as in the conventional example, but the angular load of the radial ball bearing 21 simultaneously causes the thrust load and the thrust load at the same time. Since it has been received, it may be omitted.

[0012]

[Effect of device]

 According to this invention, since the plurality of angular ball bearings 21 are mounted in series on the inner peripheral surface of the hub grip 7 that fits with the projecting end portion of the shaft 2, the thrust load 13 due to the centrifugal force is applied to the plurality of bearings. Since it is distributed and handled by the bearing, the durability of the bearing against thrust load is improved as a whole.

When the O-ring 32 is attached to the outer peripheral surface of the bearing retaining ring 15 attached to the tip of the shaft 2, the grease retained on the bearing is scattered by the centrifugal force, resulting in insufficient lubrication and durability. The lack of sex is prevented. Further, when the grease cup 34 is attached to the outer peripheral surface of the hub grip 7 and the grease is replenished to the bearing, the grease is biased to the outer bearing by the centrifugal force, and the inner bearing causes insufficient grease, that is, insufficient lubrication. There is no fear, and the lack of durability due to insufficient lubrication of the bearing can be prevented more completely.

[Brief description of drawings]

1A and 1B are views showing an embodiment of the present invention, in which FIG. 1A is a vertical sectional view and FIG. 1B is a sectional view taken along line CC of FIG.

FIG. 2 is a detailed vertical sectional view of a main part of FIG.

FIG. 3 is a vertical cross-sectional view showing a conventional blade mounting structure.

Claims (3)

[Scope of utility model registration request] 1. A helicopter rotary shaft having one end of a plurality of shafts mounted at right angles to an axial direction of the rotary shaft,
One end of a cylindrical hub grip is fitted around each of the other ends of the shafts via a bearing, and the bases of the blades are fitted and fixed to the inner peripheral surfaces of the other ends of the hub grips. A blade mounting structure for a helicopter, wherein a plurality of angular contact ball bearings are mounted in series on an inner peripheral surface of the hub grip as the bearing. 2. The helicopter blade mounting structure according to claim 1, wherein an O-ring is attached to an outer peripheral surface of a bearing retaining ring attached to the other end surface of the shaft so as to be in contact with an inner peripheral surface of the hub grip. It is characterized by being. 3. The blade mounting structure for a helicopter according to claim 1, wherein a grease cup is attached to an outer peripheral surface of the hub grip, and grease contained in the grease cup penetrates a peripheral wall of the hub grip. The bearing is supplied through the grease passage.