JPH0322583Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is an improvement of a centrifugal clutch (also called a centrifugal clutch), for example, a centrifugal clutch that performs an intermittent action on and off of power between an engine and driven equipment. Regarding.

(Prior art) Between the engine and the driven equipment, for example, in a mowing machine as shown in FIG.
A centrifugal clutch C (see FIGS. 4 and 5) is used between the drive shaft D and the drive shaft D having the slender blade S attached to the tip. This type of centrifugal clutch has a rotating body 5' on the engine side, as shown in FIGS. 6 and 7.
Then, each one end (referred to as the base end) 1a' of the clutch shoe 1', which is arranged facing each other so that the linings 1A' face outward and whose outer peripheral surface is in the shape of a semicircular arc, is connected to a pivot shaft (clutch pin) 2', etc. Rotatably supported by
The pair of opposing clutches 1' are elastically connected by a spring 4' so that they approach each other, and the opposing clutches 1'
A drum 3' on the driven equipment side is disposed such that its inner circumferential surface faces the outer circumferential surface of the drum 3' with a space in between.

The other end (referred to as a free end) 1b' of each of the clutches 1' is seated on the side surface of the proximal end 1a' of the opposite clutch 1' when the engine is stopped or at a constant rotation speed. (solid line in Figure 6,
(See the two-dot chain line in Figure 7).

When the engine starts rotating and reaches a predetermined speed or higher, as shown by the solid line in FIG. It overcomes this and moves (expands) outward in the radial direction around the pivot shaft, and presses (contacts) the drum 3', and the friction between the lining on the clutch side side and the drum caused by this pressurization causes the engine to Transmits power from the side to the driven equipment side.

(Problem to be solved by the invention) However, in a special rotation range of the engine (in this specification, it refers to a rotation range where the free end of the clutch shoe starts to come into contact with the drum), the free end of the clutch shoe comes into contact with the drum. When moving to the side,
Due to the fact that the centrifugal force acting on the clutch shoe is not large enough, even if the clutch shoe contacts the drum, the clutch shoe is rebounded by the repulsive force and the restraining force of the spring, causing it to contract (move) inward in the radial direction. ), expands (moves) toward the drum again due to centrifugal force, contacts the inner circumferential surface of the drum, and is bounced back again, and so on.

When the engine is continuously operated in a specific rotation range exhibiting such a condition, the above-mentioned operation is repeated, and as a result, the free end 1b' of the clutch and the base of the other clutch, which is seated, are A metallic sound (also simply referred to as noise) is generated due to contact (more precisely, hitting each other) with the end portion 1a'. In some cases, this metallic sound can be so loud that you think the work equipment is damaged.

This kind of metallic noise is extremely unpleasant for those using work equipment such as mowers, and it also worsens the working environment.Furthermore, it can cause damage to the contact parts of the centrifugal clutch itself. This will shorten the lifespan.

In the past, countermeasures such as attaching absorbent materials such as rubber to the seating area have been taken to eliminate the above-mentioned metallic sound, but these have peeled off after a short period of use, and no fundamental solution has been found. I couldn't stop.

The present invention was developed in view of the above-mentioned current situation, and it is an object of the present invention to provide a centrifugal clutch having a structure that does not generate the above-mentioned noise even in the above-mentioned specific rotation range.

(Means for Solving the Problems) The centrifugal clutch according to the present invention has each proximal end of the clutch shoe arranged facing each other so that each lining faces outward and having an outer peripheral surface formed in a semicircular arc shape. When the number of rotations is below a predetermined number, including when stopped, the free end of each clutch is seated in a radially inward contracted position, and when the number of rotations is greater than a predetermined number, the seated In a centrifugal clutch configured to expand radially outward from the seated position, a through-hole-like space (a through-hole or a bay-like space with one side of the through-hole open) is provided at the free end side of the seated clutch. (refers to the space formed by the recess)
By providing the clutch, the free end side of the clutch is formed into a structure with low rigidity, and the through-hole-like space is filled with a damping material. The centrifugal clutch according to the invention forms a through-hole-like space at the free end side of each clutch, thereby forming the free end side of the clutch into a structure with low rigidity. Since the hole-shaped space is filled with damping material, when the seat is seated, the end of the free end on which the seat is seated and the damping material filled in the through-hole space are elastically deformed, and the damping material is also used to dampen the seat. , the energy of the collision is absorbed, the transmission of sound and impact is reduced, and the metallic sound and impact force exerted on the abutting parts are significantly reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1a is a partially enlarged plan view with the lower half omitted to show the structure of the seating portion of the centrifugal clutch according to this embodiment, and FIG. It is a sectional view taken in the direction of arrow A. In FIGS. 1a and 1b, 1 is a clutch, 2 is a clutch pin which is a pivot shaft, 3 is a drum, and 4 is a tension type spring. The clutch 1 has a semi-circular outer circumferential surface, and is rotatably supported on a rotating body 5 on the engine side by a clutch pin 2 at a mounting boss formed at its base end 1a. A through hole 6, which is elongated in plan view, is formed in the free end side end 1b of the clutch, and the rigidity of the part that comes into contact with the proximal end of the other opposing clutch is increased. It is configured to be low.

The rest of the structure is the same as the conventional centrifugal clutch described above.

Therefore, in the centrifugal clutch equipped with the clutch shoe configured as described above, the free end side end 1b
When seated on the proximal end 1a of the other opposing clutch, the free end 1c abuts against the proximal end 1a of the clutch, and the energy from this abutment moves this end 1c inward. At the same time, the sound of collision during contact is also absorbed by the reduction in rigidity of this part due to the formation of this elongated through hole, which reduces the transmission of sound, and the resulting metallic sound is also absorbed. significantly reduced.

Furthermore, in the above embodiment, the elongated through hole 6 formed at the free end side of the clutch shoe.
If a material (damping material) 7 made of a material with a large damping effect, such as rubber, is inserted (or filled) in the mesh shown by the solid line in Fig. 2 and the mesh shown by the two-dot chain line in Fig. 1b, , it becomes more effective in reducing the above-mentioned metallic sound.

In addition, instead of the embodiment shown in FIGS. 1a and 1b, as shown in FIG. In order to show two embodiments, the connecting portion 1d (one outside and one inside) may be deleted to form a shape (bay shape) with one side open. In the case of such a shape, the rigidity of the end portion on the free end side is further reduced, so that it is more effective in reducing metallic noise. Also in this embodiment, if a damping material such as rubber is inserted (or filled) into the bay-shaped space as described above, a greater sound reduction effect can be expected.

As described above, in the centrifugal clutch according to this embodiment, the free end side of the clutch shoe is formed into various shapes with low rigidity as described above, so that the seating portion of the proximal end of the clutch shoe is It does not make a loud metallic sound when it comes into contact with the metal. Moreover, since the structure of the above-described embodiment can be molded integrally with the clutch, it can be manufactured without increasing the manufacturing cost. In addition, in the above embodiments, damping materials such as rubber are inserted into the through holes, etc., but these materials are much more durable than the conventional case where rubber or the like is pasted directly to the contact area. It is expensive and does not need to be pasted, so it is easy to insert and install in manufacturing.

In the above embodiment, the through hole is formed in the shape of an elongated hole, but the planar shape of the through hole is not limited to an elongated hole, and may be an elliptical hole or a square hole. good.

(Effects of the Invention) Since the centrifugal clutch according to the present invention is configured as described above, it does not produce a loud metallic sound when the abutting portions of the clutch abut in a specific rotation range. Further, the contact portion of the centrifugal clutch will not be damaged.

Moreover, since the structure according to the present invention can be formed simultaneously during integral molding of the clutch manufacturing process, the manufacturing cost does not increase. This means that
This is particularly useful for equipment with severe cost competition, such as mowers.

Further, as the metallic noise is reduced, the working environment for the worker is also improved.

[Brief explanation of drawings]

FIG. 1a is a partially enlarged plan view with the lower half omitted to show the structure of the seating portion of the centrifugal clutch according to this embodiment, and FIG. 2 and 3 are similar partially enlarged plan views showing other embodiments;
The figure is a perspective view showing a mowing machine using a centrifugal clutch, Fig. 5 is a partial side sectional view showing the structure of the centrifugal clutch part of the mowing machine shown in Fig. 4, and Fig. 6 is a view of the conventional centrifugal clutch part. FIG. 5 is a view taken along the line B--B in FIG. 5, showing the planar structure, and FIG. 7 is a plan view showing the main parts of the centrifugal clutch, which is the same as FIG. 6. 1... Clutch shoe, 2... Clutch pin (pivot shaft), 3... Drum, 4... Spring, 6
...Through hole, 7...Dampening material.

Claims (1)

[Scope of Claim for Utility Model Registration] Each proximal end of a clutch shoe, in which the linings are arranged facing each other facing outward and whose outer peripheral surface is formed in a semicircular arc shape, is rotatably supported by a pivot shaft, When the rotation speed is below a predetermined number, including when stopped, the free end of each clutch is seated in a radially inward contracted position, and when the rotation is above a predetermined number, it expands radially outward from the seated position. In a centrifugal clutch configured to do this, by providing a through hole-like space at the free end side of the seated clutch shoe, the free end side of the clutch shoe is formed into a structure with low rigidity. Also, a centrifugal clutch characterized in that the through hole-shaped space is filled with a damping material.