JPH0244132Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a first transmission gear and a second transmission gear that are selectively engaged with a shift gear, and a shift gear that is capable of shifting while driving one of the shift gears. a state in which a spring for slidingly biasing a slidable shifter that operates the shift gear is biased to a first transmission position where the shift gear engages the first transmission gear; A ball detent for positioning the shifter is provided in a state in which the shift gear is biased to a second transmission position in which the shift gear is engaged with the second transmission gear and is switched in accordance with the rocking of the shift operation lever, and a ball detent for positioning the shifter is provided. The present invention relates to a structure of an operation part of a gear transmission attached to the shifter in a state in which the shifter is engaged with a shifter support shaft fitted onto the outside of the shifter.

[Conventional technology]

In the structure of the operation part of such a gear transmission, conventionally, after the shifter, which operates the shift gear by operating the speed change operation lever, is operated beyond the neutral position to the first transmission position or the second transmission position, the spring The shift gear is automatically biased to slide into the first transmission position or the second transmission position only by the elastic biasing force of the shift gear.

[Problem that the invention attempts to solve]

However, according to the above structure, the shifter is urged to slide only by the elastic urging force of the spring, so in order to quickly slide the shifter, the elastic urging force of the spring must be increased.
As a result, the operating force required to operate the gear shift operating lever against the elastic biasing force of the spring increases, resulting in a decrease in operability.

The purpose of the present invention is to enable the shifter to slide quickly and to enable light and smooth gear shifting operations.

[Means for solving problems]

The characteristic structure of the present invention is that in the above-mentioned operation part structure of the gear transmission, from the first shaft part of the shifter shaft that corresponds to the center of the ball detent when the shifter is in the neutral position. When the shifter is in the first transmission position, the shifter is moved to the first transmission position by the protruding force of the ball detent in the second support shaft portion extending over the first location where the ball detent engages. A third shaft extending from the first shaft portion of the shifter shaft to a second location where the ball detent engages when the shifter is in the second transmission position so as to be slidably biased. In the spindle part,
Each of the second support shaft portion and the third support shaft portion is formed as an inclined portion so that the shifter is slidably biased to the second transmission position by the protruding force of the ball detent, and The first support shaft portion is formed such that the outer diameter of the intermediate portion of the first support shaft portion in the direction of the shifter support shaft is approximately equal to the inner diameter of the attachment portion of the shifter to the shifter support shaft. And the effects are as follows.

[Effect]

That is, when the shift gear is engaged with the first transmission gear or the second transmission gear, the shift operation is continued until the shifter that operates the shift gear is positioned beyond the neutral position to the first or second support shaft. After the lever is operated with an operating force that resists the elastic urging force of the spring and the shifter is located at the first or second support shaft portion, the shifter is moved between the elastic urging force of the spring and the protruding force of the ball detent. The resultant force causes the slider to slide to the first transmission position or the second transmission position.

Even if the attachment portion for the shifter spindle is formed on a short piece whose one end is positioned on the first spindle portion when the shifter is in the first transmission position or the second transmission position, The first support shaft part also supports the shifter using the mounting part, so that the shifter moving from one of the first transmission position and the second transmission position to the other does not get caught on the second support shaft part or the third support shaft part. to ensure smooth sliding.

[Effect of idea]

Therefore, in addition to the elastic biasing force of the spring, it is possible to effectively utilize the protrusion force of the ball detent that is originally provided to quickly slide the shifter without increasing the elastic biasing force of the spring. Compared to increasing the elastic biasing force, the operating force required for shifting can be reduced, making shifting operations easier, and the structure is simplified so that a special sliding biasing mechanism is not required. This made it economically advantageous.

Furthermore, regardless of the shape of the shifter, the shape of the first support shaft allows the shifter to slide smoothly, allowing for smooth gear changes, which also reduces the force required to operate the shift. was completed.

〔Example〕

As shown in FIG. 5, a pair of left and right running wheels 1
a, 1b, a rotary tiller 4 is connected to the rear of a self-propelled machine having an engine 2, a control handle 3, etc., and the power is transmitted from the self-propelled machine to the tiller 4, thereby creating a walking-type tiller. has been configured.

As shown in FIGS. 2 and 3, the transmission device for the wheels 1a, 1b and the tilling device 4 is constructed by connecting the output of the engine 2 to a transmission belt 5, an input pulley 6, and a main clutch installed in the input pulley 6. 7. A gear transmission 1 for power extraction that can be introduced into the transmission case 9 via the input shaft 8 and can switch the introduced power into two high and low speed stages.
0 and a driving main gear transmission 11 that can be switched to four forward speeds and two reverse speeds, and the output of the power take-off gear transmission 10 is transmitted to the power take-off clutch 1.
2. A traveling sub-driver capable of transmitting power to the rotary transmission case 35 of the tilling device 4 via the power take-off shaft 13 and the transmission case 34, and switching the output of the main gear transmission 11 to two high and low speeds. The rotational force of one of the pair of output gears 15a, 15b of the differential mechanism 15 is transmitted to the differential mechanism 15 via the gear transmission 14, and is transmitted to the steering clutch mechanism 16a and the gear reduction transmission mechanism 17a. The rotational force of the other output gear 15b of the differential mechanism 15 is transmitted to the right axle 18b via the steering clutch mechanism 16b and the gear transmission mechanism 17b. .

The traveling auxiliary gear transmission 14 includes an input shaft 19 as shown in FIG.
, the first transmission gear 20 and the second transmission gear 21
are attached to the differential gear case 15c of the differential mechanism 15 so as to be relatively rotatable, and the shift gear 22 is disposed between the transmission gears 20 and 21, and the input shaft 19 The first shift fork 23 serves as a shifter, and the first shift fork 23 serves as a shifter. When it is engaged with the first transmission gear 20, it becomes a low-speed transmission state, and when it is engaged with the second transmission gear 21, it becomes a high-speed transmission state.

As shown in FIGS. 2 and 4, the differential mechanism 15 includes a differential gear 24 that is integrally rotated and slidable by spline engagement with one of the output gears 15a. It is installed like this, and the defrot lock device 24 is attached to the second shift fork 2.
5, when it is slid into engagement with the differential gear case 15c, it enters the defrot state, and when it is moved away from the differential gear case 15c to release its engagement, it enters the defrot release state. .

The first and second shift forks 23, 25
Each of them is configured to perform operations based on the operating structure shown in FIG.

That is, the first support shaft 26 has one end fitted into the cylinder boss part 23a of the first shift fork 23 so as to be slidable and relatively rotatable, and the first support shaft 26 has one end fitted into the cylinder boss part 25a of the second shift fork 25. The second support shaft 27, which is fitted inside so as to be movable and relatively rotatable, are arranged concentrically in parallel in the axial direction, and the small diameter end 26a on one end side of the first support shaft 26 is connected to the second support shaft. 27 into the cylinder end 27a on one end side so as to be relatively rotatable, and the other end sides of both support shafts 26, 27 are attached to the mission case 9 with the ends protruding outside of the mission case 9. The first and second support shafts 26 and 27 are fixed to each other at one end so as to be relatively rotatable, so that the other support shaft 2
It is rotatably supported by the mission case 9 via 7 or 26, and the other end is directly rotatably supported by the mission case 9. In other words, the first and second shift forks 23, 25 are
The first support shaft 26 and the second support shaft 27 are arranged concentrically in parallel and slid separately in the parallel direction.
It is attached to the transmission case 9 via. Then, between the first shift fork 23 and the first support shaft 26 and between the second shift fork 25 and the second support shaft 27, a penetrating long groove 28a or 28b is formed in the cylinder boss portion 23a or 25a, respectively. A pin 29a or 29b is installed to be inclined with respect to the axes of the support shafts 26 and 27, and is slidably engaged in the long groove 28a or 28b.
When the support shaft 26 or 27 is rotated, the shift fork 23 or 25 is attached to the pin 29a or 2 due to the inclination of the long groove 28a or 28b.
The cam mechanism 30a or 30b is configured to be slidably operated in the direction of the spindle center by the cam mechanism 9b.

The first and second support shafts 26 and 27 are rotated by the swinging of an operating arm 31 or 32 attached to the end of the transmission case. The operating structure of the operating arm 31 with respect to the shaft 26 will be described in detail.

As shown in FIGS. 1 and 4, a shift operation lever 33 for swinging the operation arm 32 is interlocked and connected to the operation arm 31 by a link type interlocking mechanism 36, and the shift gear 22 is connected to the first
A first transmission position 20A where the transmission gear 20 is engaged is biased, and a second transmission position 21A where the shift gear 22 is engaged with the second transmission gear 21.
A spring 37 is attached to the speed change operation lever 33 so that the speed change operation lever 33 is biased to a biased state as the speed change operation lever 33 swings.
When the shift gear 22 exceeds the switching point P, the first support shaft 26 is rotated by the elastic biasing force of the spring 37, thereby biasing the shift gear 22 to the first or second transmission position 20A, 21A. . Then, at the first support shaft 26 that engages with a ball detent 38 attached to the first shift fork 23 for positioning the first shift fork 23, the ball detent is inserted while the first shift fork 23 is in the neutral position N. The first support shaft portion 2 corresponding to the center of 38
6A, the first shift fork 23
In the second support shaft portion 26B extending over the first location 39 where the ball detent 38 engages in the state of being in the transmission position 20A, the first shift fork 23
is slidably biased toward the first transmission position 20A by the protruding force of the ball detent 38, from the first support shaft portion 26A to the first shift fork 2.
In the third support shaft portion 26C extending over the second location 40 where the ball detent 38 engages when the ball detent 38 is in the second transmission position 21A, the first shift fork 23 each of the second support shaft portion 26B and the third support shaft portion 26C is formed as an inclined portion so as to be slidably biased to the second transmission position 21A by
The outer diameter of the first support shaft portion 26A at the intermediate portion in the first support shaft center direction is equal to the first shift fork 23.
The first support shaft portion 26A is formed to have a diameter approximately equal to the inner diameter of the attachment portion to the first support shaft 26, so that the elastic force of the spring 37 and the protruding force of the ball detent 38 are combined during a speed change operation. The first shift fork 23 is moved to the first transmission position 20 by both of them.
A or the second transmission position 21A, and the first shift fork 23 is located at the second transmission position 21A so that the end of the attachment part to the first support shaft 26 is in the first position. Even if it is located at the support shaft portion 26A, the first shift fork 23 is supported by the diameter of the first support shaft portion 26A, so that the first shift fork 23 can smoothly slide to the first transmission position 20A. It's meant to be.

[Another example]

In the embodiment described above, the spring 37 for slidingly biasing the first shift fork 23 was applied to the speed change operating lever 33, but it may also be provided to act on the operating arm 31, and the location of the spring 37 is Can be changed freely.

[Brief explanation of drawings]

The drawings show an embodiment of the structure of the operation part of the gear transmission according to the present invention, and FIG. 1 is a partially cutaway sectional view showing the engaged state of the ball detent, and FIG.
The figure is a cross-sectional view of the transmission, Figure 3 is a cross-sectional view of the power take-off shaft installation part, Figure 4 is a partially cutaway rear view of the shift fork operating part, and Figure 5 is a side view of the entire walk-behind cultivator. be. 20...First transmission gear, 20A...First transmission position, 21...Second transmission gear, 21A...Second
Transmission position, 22...Shift gear, 23...Shifter, 26...Shifter spindle, 26A...First spindle portion, 26B...Second spindle portion, 26C...Third spindle portion, 33... Gear shift operation lever, 37...
Spring, 38... Ball detent, 39...
1st location, 40...2nd location, N...neutral position.

Claims (1)

[Scope of utility model registration request] The first transmission gear 20 and the second transmission gear 21 to which the shift gear 22 is selectively engaged and the shift gear 22 are configured to change speed while being driven, and a sliding operation for operating the shift gear 22. The spring 37 for slidingly biasing the shifter 23 is moved to the first transmission position 20A where the shift gear 22 engages the first transmission gear 20.
and a second transmission position 21 where the shift gear 22 engages with the second transmission gear 21.
The shifter 23 is provided in a state in which the shifter 23
A gear transmission operating section structure in which a ball detent 38 for positioning is attached to the shifter 23 in a state where it engages with the shifter support shaft 26 on which the shifter 23 is fitted, the shifter support shaft 26, when the shifter 23 is at the neutral position N, the first support shaft portion 26A corresponds to the center of the ball detent 38, and when the shifter 23 is at the first transmission position 20A, the ball detent is 1st location 39 where 38 engages
In the second support shaft portion 26B, the second support shaft portion 26B of the shifter support shaft 26 is configured such that the shifter 23 is slidably biased toward the first transmission position 20A by the protruding force of the ball detent 38. When the shifter 23 is in the second transmission position 21A from the first support shaft portion 26A, the ball detent 38
The third support shaft portion 26 extends over the second location 40 where the
At C, the shifter 23 is moved to the second transmission position 2 by the protruding force of the ball detent 38.
1A so that the second support shaft portion 2 is slidably biased.
6B and the third support shaft portion 26C are each formed as an inclined portion, and the outer diameter of the first support shaft portion 26A at the intermediate portion in the direction of the shifter support shaft is set to the position where the shifter 23 is attached to the shifter support shaft 26. The first support shaft portion 26 is approximately equal to the inner diameter of the first support shaft portion 26
The structure of the gear transmission operating section formed by A.