JPH0444933Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a speed change operation structure for a continuously variable transmission.

(b) Conventional technology In most continuously variable transmissions, the following steps are taken:
A speed change rod that controls the speed change member is connected to a speed change arm that is rotatably installed around a fulcrum pin, and the speed is changed by directly rotating the speed change arm. Therefore, the amount of rotation of the speed change arm and the amount of shift of the transmission correspond almost proportionally.

(c) Problems to be solved by the invention This makes the structure simple, but on the other hand, it is impossible to change the subtlety of speed control depending on the speed range.

For example, these things can be said when this continuously variable transmission is applied to a transmission, etc. of a traveling working vehicle that travels at low speeds while performing some kind of work, unlike when it simply travels on the road at high speeds.

In other words, it is necessary to be able to set the speed more precisely when driving for work, but in order to be able to do this, the amount of movement of the gear shift rod must be small in this speed range even if the gear shift arm is moved significantly. .

(d) Means to solve the problem Therefore, in this invention, in addition to providing a shift arm so that it can freely rotate around a fulcrum pin, a shift rod is locked to this shift arm, and the amount of rotation of this shift arm is controlled. In the shift operation structure of a continuously variable transmission that operates the transmission in high and low gears accordingly, the rotation of this shift arm is
This is done by bringing into contact an operating member formed on a shift lever that is rotatable around a fulcrum pin provided near the shift arm, and the form of this operating member is
When operating the shift lever in a high speed range, the amount of rotation of the shift arm is larger than the amount of rotation of the shift lever, and when operating the shift lever in a low speed range,
While the basic configuration is such that the amount of rotation of the speed change arm is set to be small, in this configuration, the operating member is two rollers provided at different radii from the fulcrum pin, and The above-mentioned problems were solved by optionally having the member be a continuous cam piece.

(e) Effect As a result, the rotation of the gear shift arm is performed by the operating member provided on the gear shift lever, and this operating member changes the amount of rotation of the gear shift arm at high speed and low speed (high speed and low speed). The effect is large at high speeds and small at low speeds, so speed settings can be made more precisely at low speeds.

(F) Embodiments Hereinafter, embodiments of this invention will be described with reference to the drawings. FIGS. 1 to 3 are side views showing the operating state of the speed change operation structure according to this invention, and FIG. FIG. 7 is a side view showing another embodiment.

First, as shown in FIGS. 1 to 3, a shift arm 2 is provided rotatably around a fulcrum pin 3, which is connected to a shift rod 1 that operates a shift member of a continuously variable transmission (not shown). . Next, in the vicinity of this shift arm 2, a shift lever 5 is provided which can also freely rotate around a fulcrum pin 4. In these configurations, reference numeral 6 denotes a support member, from which brackets 7 and 8 extend, respectively, to which the aforementioned fulcrum pins 3 and 4 are pivotally attached.

On the other hand, the shift lever 5 is formed with an operating member 9 that contacts the shift arm 2 and rotates the shift arm 2 when the shift lever 5 rotates.

By the way, the shape of this operating member 9 is set so that the rotation radius of the shift arm 2 becomes large when the shift lever 5 is operated in a high speed range, and becomes small in a low speed range.

As long as it meets this demand, it does not matter what form it takes, but for example, as shown in FIG.
A and 9b are conceivable.

Among these, the state shown in FIG.
is in an almost upright state and at a mid-height position, but in this case, both rollers 9a and 9b are in contact with the speed change arm 2, and either roller 9
This does not mean that a and 9b are acting.

The state shown in FIG. 2 is when the shift lever 5 enters a high speed range, and here the roller 9b, which is longer in length b from the fulcrum pin 4, acts.

Therefore, the tilt angle of the shift lever 5 is θ, the length from the fulcrum pin 3 of the shift arm 2 to the point of action of the roller 9b is c, and the length from the fulcrum pin 3 to the pivot point of the shift rod 1 is also If r, then the distance S1 that the shift rod 1 moves when the shift lever 5 is tilted by the tilt angle θ is S1=bsinθ·r/c.

The state shown in FIG. 3 is when the shift lever 5 is set to a low speed range, but in this case, the shorter length a from the fulcrum pin 4 acts, and similarly, the shift arm 2
If the length from the fulcrum pin 3 to the point of application is d, then the distance S2 that the shift rod 1 moves when the shift lever 5 is tilted by θ in the opposite direction to the above is:
This means that S2=asinθ・r/d.

Therefore, if we find the ratio of both, S1/S2=bd/
ac, so a=1, b=2, c=2,
If d=3, then S1/S2=3, and when the shift lever 5 is in the low speed range, the shift rod 1 is actually three times more precise than when it is in the high speed range.

What is shown in FIG. 4 is an example in which a continuous cam piece 9c is used as the operating member 9. In this case as well, when the shift lever 5 is operated in a high speed range, the rotation radius of the shift arm 2 becomes large. Well, see you again.
There is no difference in that it is made smaller in the low speed range.

In any of the above examples, the shift arm 2 is always connected to the shift lever 5 by the spring 10.
In addition to being tensilely biased toward the side, considerable resistance is applied to the rotation of the gear shift lever 5.
Even if a small amount of force is applied, it will not move from its set position.

(g) Effects of the invention Since this invention is as described above,
That is, the rotation of the shift arm 2 linked to the shift rod 1 that operates the shift member of the continuously variable transmission is controlled by a shift lever 5 that is rotatable around a fulcrum pin 4 provided in the vicinity of the shift arm 2. The action member 9 is brought into contact with the action member 9, and the shape of the action member 9 is such that when the shift lever 5 is operated in a high speed range, the amount of rotation of the shift arm 2 is smaller than the amount of rotation of the shift lever 5. In addition, since the rotation amount of the shift arm 2 is set to be small when operating in a low speed range, even if the shift lever 5 is moved greatly, especially in a low speed range, the shift rod 1 will not move. This means that it won't move as much, allowing you to set the speed more precisely. Therefore, this invention is suitable for application to transmissions of various traveling work vehicles that require delicate speed control in low speed ranges.

This can be achieved easily and at low cost by using the acting member 9 as the two rollers 9a and 9b as described above, or by using a continuous cam piece 9c.

[Brief explanation of the drawing]

1 to 3 are side views showing the operating state of the speed change operation structure according to this invention, and FIG. 4 is a side view showing another embodiment. Code, 1...shift rod, 2...shift arm,
3... Fulcrum pin, 4... Fulcrum pin, 5... Speed change lever, 9... Action member, 9a, 9b... Roller,
9c...Cam piece.

Claims (1)

[Scope of Claim for Utility Model Registration] In addition to providing a shift arm 2 rotatably around a fulcrum pin 3, a shift rod 1 is attached to this shift arm 2.
In the shift operation structure of a continuously variable transmission that locks the shift arm 2 and operates the transmission to high or low speed according to the amount of rotation of the shift arm 2, the rotation of the shift arm 2 is controlled by a mechanism provided near the shift arm 2. This is done by bringing into contact an operating member 9 formed on the shift lever 5 that is rotatable around the fulcrum pin 4, and the shape of the operating member 9 is such that when the shift lever 5 is operated in a high speed range, the shift lever 5 is 5. A continuously variable transmission characterized in that the amount of rotation of the shift arm 2 is set to be larger than the amount of rotation of the gear change arm 2, and the amount of rotation of the shift arm 2 is set to be smaller in operation in a low speed range. Shift operation structure. A shift operation structure for a continuously variable transmission, wherein the operating member 9 is two rollers 9a and 9b provided at different radii from the fulcrum pin 4, as set forth in claim 1. A speed change operation structure for a continuously variable transmission, wherein the operating member 9 is a continuous cam piece 9c as described in claim 1 of the registered utility model claim.