JPH0434006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a transmission main shaft with a pair of left and right friction clutches which are normally held in a neutral state and which transmit transmission to the forward and reverse transmission mechanisms, respectively. A shift ring is interposed in the middle part of the main transmission shaft, and by sliding the shift ring with a shift arm, one of the pair of friction clutches is selected and connected in a forward or reverse direction. This invention relates to improvements in the constructed clutch mechanism.

In conventional clutch mechanisms of this type, when the friction plate on the movable side of the friction clutch or the drum on the fixed side wears out, their pressing force decreases, resulting in poor transmission efficiency and problems with the force transmission system. This caused damage due to looseness.

The present invention has been made in view of and to solve the problems of the prior art, and provides a novel clutch mechanism that can always keep the pressing force of the movable friction plate constant. The purpose is to

In order to achieve this purpose, the clutch mechanism of the present invention has a pair of friction clutches facing each other on the transmission main shaft, which are normally held in a neutral state and transmit transmission to the forward and reverse transmission mechanisms, respectively. A shift ring is interposed between the clutches at an intermediate portion of the main transmission shaft, and by sliding the shift ring with a shift arm, one of the pair of friction type clutches can be selected to be either positive or positive. In a clutch mechanism configured to switch and connect in reverse, the clutch arm is fixed to one end of a shift pin which is rotatably supported by a gear case, and a link arm is rotatably pivoted to the clutch arm. At the same time, the extended end side of the clutch arm is formed into two forks, the abutment plate provided on the link arm is faced between the two forks, and a roller arm is attached to the upper end of the link arm,
Further, the link arm is equipped with a pair of left and right coil springs, with the link arm side serving as a lower receiving part and the roller arm side serving as an upper pushing part, and the roller arm is in contact with forward and reverse action cams. The roller is pivotally supported, and these forward and reverse action cams are fixed to a cam arm that can be rotated by a lever, and when either of these forward and reverse action cams is in the operating state, the It is characterized in that the friction plate on the movable side of the friction type clutch on that side is configured to be pressed against the friction plate on the fixed side.

Hereinafter, the present invention will be described in detail with reference to illustrative embodiments.

In FIG. 1, reference numeral A denotes a clutch mechanism, in which a pair of left and right friction clutches a and a, which are normally held in a neutral state by springs 2, are provided on the transmission main shaft 1, and the transmission main shaft is connected between them. A shift ring 3 is interposed in the part 1, and the shift ring 3
By sliding the clutch by the shift arm 4, one of the friction clutches a and a is selected and connected in the forward or reverse direction.

Each of the friction type clutches a includes a fixed side friction plate (drum) 5 fixed to the transmission main shaft 1, and a movable side friction plate (drum) 5 that is loosely fitted to the transmission main shaft 1 and integrated with the shift ring 3. The gear part 6a, which is integrally provided on the boss part of the friction plate (cone) 6 on the movable side of one clutch a, meshes with the transmission gear G of the transmission path on the forward side, and the other A gear portion 6a provided integrally with the boss portion of the friction plate (cone) 6 on the movable side of the clutch a meshes with the transmission gear G' of the transmission path on the reverse side. Then, the drum 5
The spring 2 is wound around the portion of the main transmission shaft 1 between the cone 6 and the cone 6 (FIG. 6).

The shift arm 4, as shown in FIG.
It is fixed to a shift pin 7, and a clutch arm 8 is fixed to one end of the shift pin 7. The shift pin 7 is pivotally supported by the gear case 9 (fifth
figure).

A link arm 10 extending upward is rotatably attached to the front surface of the clutch arm 8. 11 is a shaft pin. The extended end side of the clutch arm 8 extending upward from the shaft pin 11 is formed into a bifurcated portion, and an abutment plate 10a protruding from the back surface of the link arm 10 is exposed between the bifurcated pieces 8a, 8a. (Figures 1 and 2).

Adjustment bolts 12, 12 are provided on each of the forked pieces 8a, 8a at a predetermined interval and abut against the side surface of the plywood 10a, so as to be movable forward and backward.
Fig. 2).

A roller arm 13 is attached to the upper end of the link arm 10. Reference numeral 14 denotes a mounting bolt that passes through the shaft cylinder 13a that protrudes forward at the center of the lower part of the roller arm 13 and is tightened.

The roller arm 13 has a substantially fan-shaped front face and expands downward, and has collar pieces 13b, 13b that protrude forward on both sides of its lower edge, and each collar piece 13b has a through hole 13c, respectively. is opened, and a roller 15 is pivotally supported on the back surface of its upper end. The roller 15 is in contact with a forward/reverse action cam 16.

The respective collar pieces 13b, 13b and the receiving portions 10b, 10 protrude forward on the lower left and right sides of the link arm 10.
A pair of left and right coil springs 17, 17 are provided between
is set. 18 is each coil spring 1
This is a bolt that winds and supports 7.

The bolt 18 is attached to the umbrella portion 1 as shown in FIG.
8a, a protrusion 18b above it, and a bolt main body 18c below it. In the wound state, the lower end 18d of the link arm 10 is passed through the receiving portion 10b of the link arm 10 in a loosely fitted manner, and a seat plate 18 is attached to the portion protruding downward from the receiving portion 10b.
It is fastened with nut 18f with e intervening.

As shown in FIG. 2, the forward and reverse action cam 16 has a positive (forward action) cam 16a extending upwardly so as to sandwich the roller 15 above and below the outer edge of a generally fan-shaped cam arm 20 that can be rotated by a link 19. A reverse (reverse action) cam 16b is attached below.

As shown in FIGS. 4 and 5, the link 19 has a lower end pivotally supported on the side surface in front of the pivot point 20a of the cam arm 20, and an upper end attached to the arm 22 that is integrated with the main shift lever 21. It is pivotally supported. 19a is an upper pivot point of the link 19;
b is a pivot point below the link 19. The main shift lever 21 has a guide groove 23 in which a forward position F, a neutral position N, and a reverse position R are set, as shown in FIG. It is designed to move, and returns to the neutral position N under normal conditions by the bias of the spring 2 (FIG. 6).
21a is a fulcrum shaft of the main shift lever 21.

As shown in FIG. 7, the working cam 16 has an inclined plane 16c formed at least during the cam pressing stroke l, and this inclined plane 16c becomes a wedge acting surface when the roller 15 is pressed. Efforts are being made to reduce the operating load. 16d
is a vertical plane that continues to the end of the inclined plane 16c, and 1
The coil spring 17 is compressed by another inclined plane 6e following the starting end of the inclined plane 16c. Therefore, when the starting end of this inclined plane 16c comes into contact with the roller 15, as shown in FIG. While the end of 16c contacts the roller 15, the inclined plane 16c acts as a wedging surface and presses against the roller 15, forcing the cone 6 into the drum 5 via a predetermined conduction path. Then, as shown in FIG. 9, when the roller 15 rides on the vertical surface 16d of the cam 16, the pressing force of the cone 6 against the inside of the drum 5 is maintained.

Further, as shown in FIG. 5, the forward action cam 16
A and the backward action cam 16b may be made of members of the same shape, with only the action surfaces A and B being different. This makes it possible to perform both functions by manufacturing cams of the same shape, resulting in lower manufacturing costs.

As shown in FIG. 10, each cam 16 has a round hole 16g and an adjustment elongated hole 16h, and a fixing pin 16f is inserted through these holes.
6 may be adjustable and fastened to the mounting seat 20b of the cam arm 20. That is, in this case, the attachment of each cam 16 can be adjusted by changing the tightening position of the adjustment elongated hole 16h of each cam 16 and the fixing pin 16f according to the wear of the roller 15. ing.

In this case, by using the same cam shape and opening the round hole 16g and the adjustment long hole 16h, the adjustment range of the point of action is larger on the forward side than on the reverse side. It is configured so that it can be removed.

Next, the operation of the clutch mechanism constructed as described above will be explained.

In FIG. 4A, when the main shift lever 21 is rotated counterclockwise around the fulcrum shaft 21a, the link 19 is moved downward via the arm 22 integrated with the main shift lever 21, and the cam arm 20 is rotated around the fulcrum shaft 20a. Rotate it counterclockwise.

Then, the forward action cam 16 of the cam arm 20
In the downward movement of a, the roller 15 first rolls along the inclined surface 16e of the roller 15, as shown in FIG. It rotates clockwise around the shaft pin 11, and the opposing plywood 10a on the back side
Rotate clockwise until it hits the tip of the adjusting bolt 12 on the right side (in Figure 3, A). The clutch arm 8 rotates clockwise around the shift pin 7 via the adjuster bolt 12, and the shift arm 4, which is integrated with the shift pin 7, also rotates clockwise, and the shift ring 3 and cone 6 are rotated clockwise.
The cone 6 is moved to the left along the main transmission shaft 1 against the bias of the cone 6 , and the cone 6 is brought into contact with the inside of the drum 5 .

Subsequently, the advancing cam 16 of the cam arm 20
As shown in FIG. 3B, by the downward movement of the roller a, the roller 15 further rolls along its cone pressing slope 16c, and at the same time the roller arm 13 and link arm 10 integral with the roller shaft 15a The abutment plate 10a rotates clockwise around the shaft pin 11, and the abutment plate 10a strongly presses the adjusting bolt 12 to the right side, and the right side collar piece 13b of the roller arm 13 serves as an umbrella for the right side bolt 18. Part 18
a downwardly against the bias of the coil spring 17. At this time, the seat plate 18 at the lower end of the bolt 18
A gap b corresponding to the cone pressing load is created between e and the lower surface of the receiving portion 10b of the coil spring 17. Then, a clockwise rotational force is applied to the clutch arm 8, shift pin 7, and shift arm 4 via this adjuster bolt 12, and the shift ring 3 is further strongly moved to the left along the main transmission shaft 1. and press the cone 6 into the drum 5.

Then, as shown in FIG. 3B, when the roller 15 rides on the vertical surface 16d from the end of the cone pressing stroke inclined surface 16c of the forward action cam 16a, the pressing force of the cone 6 into the drum 5 is maintained. Ru. Compressive force f of the coil spring 17 at this time
Assume that a pressing force f is generated from the roll 15 on its vertical surface 16d, and that the cone 6 and drum 5
Assuming that a pressing force f'' is generated between the inner surfaces, the shift pin 7
When the distance from the axis of
f′×l′/l″ holds true.

As described above, in the clutch mechanism of the present invention, a pair of friction type clutches a and a are mounted on the transmission main shaft 1 on the left and right sides, which are normally held in a neutral state and transmit transmission to the forward and reverse transmission mechanisms, respectively. A shift ring 3 is interposed in the intermediate portion of the main transmission shaft 1 between the clutches a and a, and by sliding the shift ring with the shift arm 4, the pair of friction clutches a and - In a clutch mechanism configured to switch between forward and reverse connections by selecting either a, the clutch arm 8 is fixed to one end of the shift pin 7 to which the shift arm 4 is fixed and pivotally supported by the gear case 9. A link arm 10 is rotatably pivoted to the clutch arm 8, and the extended end of the clutch arm is formed into two forks, and the abutment plate 10a provided on the link arm 10 is placed between the two forks. A roller arm 13 is attached to the upper end of the link arm 10, and a pair of left and right coil springs 17, 17 are attached to the link arm 10.
The roller arm 13 is equipped with a lower receiving part 10b on the 0 side and an upper pushing part, and the roller arm 13 is equipped with a roller 15 that comes into contact with normal and reverse working cams 16a and 16b. The action of cam 1
6a and 16b are fixed to a cam arm 20 that can be rotated by a lever 21, and these normal and reverse action cams 16
When either a or 16b is in the operating state,
Since the friction plate 6 on the movable side of the friction clutch on that side is pressed against the friction plate 5 on the fixed side via the coil spring 17 on that side, conventionally, when the cone wears out, the cone pressing stroke decreases. , the coil spring compression force f decreased, and as a result, the cone compression force f' decreased, but in the case of the present invention, the stroke is sufficiently large due to the shape of the cam itself and the biasing force of the coil spring relative to the amount of wear on the cone. Because of this, the pressing force f'' due to wear hardly changes.Also, even if there is play in the transmission system, it can be absorbed by the coil spring.Furthermore,
Even if the cone has too much friction or abnormal wear occurs in various parts, the adjusting bolt can be adjusted to set the pressing stroke to a predetermined length, ensuring proper power transmission.

[Brief explanation of drawings]

Fig. 1 is a front view of the clutch mechanism of the present invention, Fig. 2 is a front view of the clutch mechanism of the present invention;
The figure is a side view of the above clutch mechanism, Figures 3A and 3B are front views showing the action of the above clutch mechanism, Figure 4A is a vertical sectional view of the transmission device incorporating the above clutch mechanism, and Figure 4B is a longitudinal sectional view of the transmission device incorporating the same clutch mechanism. is a plan view of the same transmission device, No. 5
The figure is a longitudinal sectional front view of the vicinity of the forward and reverse acting cam, which is the main part of the above transmission device, FIG. 6 is a longitudinal sectional front view of the vicinity of the transmission main shaft, which is the main part of the above transmission device, and FIG. 7 is another embodiment. 8 and 9 are front views showing the action of the clutch mechanism that employs the operating cam, and FIG. 10 is a front view of the forward/reverse acting cam and the cam arm to which it is attached, which is another embodiment. FIG. Explanation of drawing symbols, A...Clutch mechanism, a...
Friction type clutch, 1...transmission main shaft, 2...spring,
3...Shift ring, 4...Shift arm, 5...
...Friction plate (drum) on the fixed side, 6...Friction plate (cone) on the movable side, 6a...Gear portion, 7...Shift pin, 8...Clutch arm, 8a...Forked piece,
9... Gear case, 10... Link arm, 10
a... Boundary plate, 10b... Receiving portion, 11... Shaft pin, 12... Adjustment bolt, 13... Roller arm, 13a... Shaft cylinder, 13b... Flange piece, 13
c...Through hole, 14...Mounting bolt, 15...Roller, 15a...Roller shaft, 16, 16a, 16b
...Action cam, 16c... Inclined plane, 16d...
Vertical surface, 16e... Inclined plane, 16f... Fixing pin, 16g... Round hole, 16h... Oblong hole, 17...
Coil spring, 18... Bolt, 18a... Umbrella section,
18b...Protrusion, 18c...Bolt main body, 18
d... lower end, 18e... seat plate, 18f... nut, 19... link, 19a, 19b... pivot point, 20... cam arm, 20a... pivot point, 2
0b...Mounting seat, 21...Shift lever, 21a...
...Fulcrum shaft, 22...Arm, 23...Guide groove,
l... Stroke, l', l''... Distance, F... Forward position, N... Neutral position, R... Reverse position, G,
G'...Transmission gear.

Claims (1)

[Claims] 1 A pair of friction type clutches a and a, which are normally held in a neutral state and are respectively transmitted to the forward and reverse transmission mechanisms, are provided on the transmission main shaft 1, facing each other on the left and right, and between the clutches a and a, A shift ring 3 is interposed in the intermediate portion of the main transmission shaft 1, and by sliding the shift ring with a shift arm 4, one of the pair of friction type clutches a and a can be selected for forward or reverse rotation. In this clutch mechanism, a clutch arm 8 is fixed to one end of a shift pin 7 to which the shift arm 4 is fixed and is pivotally supported by a gear case 9, and a link arm 10 is rotated around the clutch arm 8. The clutch arm is movably attached to the shaft, and the extended end side of the clutch arm is formed into two forks, with the abutment plate 10a provided on the link arm 10 facing between the two forks, and a roller at the upper end of the link arm 10. An arm 13 is attached to the link arm 10, and a pair of left and right coil springs 17, 17 are attached to the link arm 10.
The roller arm 13 is equipped with a lower receiving part 10b on the 0 side and an upper pushing part, and the roller arm 13 is equipped with a roller 15 that comes into contact with normal and reverse working cams 16a and 16b. The action of cam 1
6a and 16b are fixed to a cam arm 20 that can be rotated by a lever 21, and these normal and reverse action cams 16
When either a or 16b is in the operating state,
A clutch mechanism characterized in that the friction plate 6 on the movable side of the friction type clutch on that side is pressed against the friction plate 5 on the fixed side via a coil spring 17 on that side.