JPH0638437U - Bearing device of transmission shaft in brush cutter - Google Patents

Abstract

(57) [Abstract] [Purpose] The pipe 54 of the brush cutter 50 including a transmission shaft 53 for transmitting the rotational driving force of the rotational drive source 51 to the rotary blade 52, and a pipe 54 into which the transmission shaft 53 is inserted. A bearing device for rotatably supporting the transmission shaft 53 inside,
(EN) A bearing device which does not damage the transmission shaft 53, has a long service life, and requires little replacement. A bearing body 2 which constitutes an inner diameter portion of a bearing device and is in sliding contact with the transmission shaft 53 on the inner surface side thereof, and an outer diameter portion of the bearing device, which is press-fitted into an appropriate position in the pipe 54 to form the bearing. A bearing support body 3 for supporting the body 2 is formed, and the bearing body 2 is formed so that the center portion in the length direction of the inner surface thereof rises.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is attached to the front end of the operating rod 54 from a prime mover 51 inserted in the pipe-shaped operating rod 54 of the brush cutter 50 as shown in FIG. 5 and provided at the rear end of the operating rod 54. The present invention relates to a bearing device that rotatably supports a transmission shaft 53 that transmits a rotational driving force to the cutting blade 52 in the operating rod 54.

[0002]

[Prior art]

 In the bearing device 40 as described above, since the operating rod 54 is long, the power transmission shaft 53 inserted in the operating rod 54 is easily bent. In order to support the transmission shaft 53, a plurality of them are provided at appropriate positions within the operating rod 54.

As shown in FIG. 4, the conventional bearing device 40 is generally composed of a bearing body 41 that constitutes an inner diameter portion thereof and a bearing support body 42 that constitutes an outer diameter portion thereof. The bearing body 41 is in sliding contact with the transmission shaft 53 on the inner surface thereof. On the other hand, the bearing support body 42 is press-fitted into the operating rod 54 to support the bearing body 41, and prevents the vibration generated by the rotation of the transmission shaft 53 from being directly transmitted to the operating rod 54. It plays the role of a vibrating material or a cushioning material.

Conventionally, the bearing body 41 has a linear inner diameter cross section so that the entire inner surface of the bearing body 41 is in sliding contact with the transmission shaft 53.

[0005]

[Problems to be solved by the device]

 However, in the case of the above-described conventional structure, when used for a long period of time, a phenomenon occurs in which both ends of the bearing body 41 in the lengthwise direction are significantly worn away by being rubbed by the bending of the unsupported portion of the transmission shaft 53. Was there. For this reason, the transmission shaft 53 is easily damaged, the life of the bearing device 40 is short, and there is a problem that complicated replacement work must be performed frequently.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bearing device that does not damage the transmission shaft, has a long life, and requires little replacement.

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a transmission shaft in a pipe of a brush cutter, the transmission shaft transmitting a rotational drive force of a rotational drive source to a rotary blade, and a pipe into which the transmission shaft is inserted. A bearing device that rotatably supports the bearing device, the bearing device forming an inner diameter portion of the bearing device, the inner surface of which is in sliding contact with the transmission shaft, and the outer diameter portion of the bearing device. A bearing support body press-fitted into a position to support the bearing body, wherein the bearing body is formed such that the central portion in the longitudinal direction of the inner surface thereof rises.

[0008]

[Action]

 According to this invention, the central portion of the surface of the bearing body in the longitudinal direction is raised in advance, and the curved surface is formed toward both ends, so that the transmission shaft is not damaged and the life is long and frequent. No need to replace.

[0009]

【Example】

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

FIG. 5 is an overall perspective view of the brush cutter 50. In the figure, 51 is a prime mover as a rotary drive source of an air-cooled two-cycle gasoline engine, and 52 is a rotary drive force of the prime mover. A cutting blade, 53 is a transmission shaft for transmitting the rotational driving force of the prime mover 51 to the cutting blade 52, 54 is an operating rod made of a light-weight metal pipe in which the transmission shaft 52 is inserted, and 55 is an operating rod 54. It is an operation handle attached to the barrel.

The bearing device 1 of the present invention replaces the conventional bearing device 40 shown in FIG. 4 and is press-fitted into an appropriate position inside the operating rod 54 to rotatably support the transmission shaft 53. One example thereof is shown in FIGS.

The bearing device 1 of the illustrated embodiment has a bearing body 2 that is in sliding contact with the transmission shaft 53 of the brush cutter 50 on the inner surface side thereof, and a bearing support body that is formed around the bearing body 2 in an annular shape. 3 and 3. The bearing support body 3 supports the bearing body 2 in the operating rod 54 and reduces the vibration caused by the rotation of the transmission shaft 53.

As is clear from FIG. 1, in this embodiment, the central portion of the inner surface of the bearing body 2 in the longitudinal direction (axial direction of the transmission shaft 53) bulges inward in the radial direction, and from the bulged portion, A smooth curved slope is formed on both ends of the bearing body. Although the bulging amount is exaggerated in the drawing, it may be about 10 μm when the diameter of the transmission shaft 53 is about 7 mm.

The bearing device 1 shown in FIG. 1 is manufactured, for example, as follows.

First, the bearing support 3 is molded by an injection molding method. As the material of the bearing support 3, for example, phenol resin having good thermal conductivity is used. This is because frictional heat generated by friction between the transmission shaft 53 and the bearing body 2 is transmitted to the operating rod 54 through the bearing support body 3 to facilitate the escape of heat, and at the same time, the vibration absorbing property and the press-fitting property. This is to give sexuality.

Next, the bearing support 3 formed as described above is inserted into the mold frame 4 in which the mold is opened, as shown in FIG. The mold 4 is a mold for molding the bearing device 1 of the present invention, and has a shape in which a mold core 6 having a circular cross section is projected in the central portion of the cavity 5 and can be opened and closed. The mold core 6 has a shape corresponding to the inner diameter cross-sectional shape of the bearing body 2, and is formed so that the diameter gradually becomes smaller toward the central portion in the length direction. Then, the molded bearing support 3 is inserted into the cavity 5 in the mold 4.

In this state, there is a gap S between the inner surface 3a of the bearing support 3 and the peripheral surface 6a of the mold core 6, and this gap S has a mold cover as shown in FIG. After closing 7, the thermosetting resin to be the bearing 2 is injected and filled from the injection port 8.

As the material of the bearing body 2, polycyclic aromatic hydrocarbons such as naphthalene, anthracene, phenanthrene, pyrene and coal tar pitch are cross-linked with paraxylylene glycol by an acid catalyst and have excellent self-lubricating heat curing. Resin is used. This type of thermosetting resin has excellent heat resistance, sliding properties, mechanical properties, chemical resistance, and electrical properties, as well as good moldability and cost performance, making it the most suitable material for bearing device 1 of the present invention. It is suitable, and seizure phenomenon due to oil shortage does not occur unlike conventional metal bushes.

The bearing support 3 can also be made of the same thermosetting resin.

As described above, the bearing body 2 is integrally formed with the bearing support body 3, and the bearing device 1 of this embodiment is completed. The bearing body 2 is formed with a curved inclined surface corresponding to the shape of the mold core 6 from the central portion in the length direction to both ends thereof.

According to the manufacturing method as described above, compared with the conventional manufacturing method in which the bearing body 2 and the bearing support body 3 are individually molded and then the bearing body 2 is press-fitted or bonded into the bearing support body 3. In addition, manufacturing efficiency can be improved and cost can be reduced because the process can be omitted.

In addition, when the bearing support 3 is molded, if the inner surface of the bearing support 3 is formed with appropriate detents, the coupling with the bearing 2 becomes stronger. The inconvenience that the bearing body 2 separates from the bearing support body 3 and rotates together with the high speed rotation of the transmission shaft is also eliminated.

In the embodiments of the drawings, the case where the bearing support 3 is formed in advance and then the bearing body 2 is formed integrally with the bearing support 3 has been described. Needless to say, the bearing body 2 may be molded in advance by an injection molding method and the bearing support body 3 may be integrally molded by the mold 4 using the injection molding method.

[0024]

[Effect of device]

 According to the bearing device of the present invention configured as described above, the transmission shaft is not damaged, the life is long, and it is economical. Further, unlike the conventional one, it is not necessary to frequently perform the complicated replacement work of the bearing device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a bearing device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a first stage of the method for manufacturing the bearing device shown in FIG.

3 is a vertical cross-sectional side view showing a second stage of the method for manufacturing the bearing device shown in FIG. 1. FIG.

FIG. 4 is a cross-sectional view showing a conventional bearing device.

FIG. 5 is an overall perspective view of the brush cutter.

[Explanation of symbols]

 2 bearing body 3 bearing support 50 mower 51 rotary drive source 52 rotary blade 53 transmission shaft 54 pipe

Claims (1)

[Scope of utility model registration request] 1. A mowing provided with a transmission shaft (53) for transmitting the rotational driving force of a rotational drive source (51) to a rotary blade (52) and a pipe (54) into which the transmission shaft (53) is inserted. The transmission shaft (53) in the pipe (54) of the dispenser (50)
A bearing device that rotatably supports a bearing body (2) that constitutes an inner diameter portion of the bearing device and that is in sliding contact with the transmission shaft (53) on the inner surface side thereof, and an outer diameter portion of the bearing device. A bearing support body (3) that is press-fitted into the pipe (54) at an appropriate position to support the bearing body (2), and the bearing body (2) has a substantially central portion in the longitudinal direction of its inner surface. A bearing device for a transmission shaft in a brush cutter, wherein the bearing device is formed so as to rise.