JP3601914B2 - Gear transmission structure - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gear transmission structure configured so that transmission and transmission cutoff operations can be performed by engaging and separating first and second spur gears (an internal gear and an external gear) from each other.
[0002]
[Prior art]
The gear transmission structure as described above includes first and second spur gears, and from the occlusal position where the gear teeth of the second spur gear engage with the gear teeth of the first spur gear, and from the gear teeth of the first spur gear. There is a configuration in which the second spur gear is slidable in the axial direction over a separation position at which the gear teeth of the second spur gear are separated, and from the first spur gear to the second spur gear at the engagement position, or Power is transmitted from the second spur gear to the first spur gear.
[0003]
An internal gear and an external gear are provided as another gear transmission structure, and the external gear (or the internal gear) is engaged with the occlusal position where the internal gear and the external gear engage, and the internal gear and There is a configuration in which the external gear is slidably operable over a separation position where the external gear is separated, and power is transmitted from the internal gear to the external gear or from the external gear to the internal gear at the occlusal position.
[0004]
[Problems to be solved by the invention]
In the above-described gear transmission structure, when the second spur gear is configured to be slidable along the support shaft, due to a tolerance in a fitting portion between the support shaft and the second spur gear, an error in machining, or the like, The second spur gear may be slightly inclined with respect to the support shaft (falling phenomenon) (see FIG. 7 ).
[0005]
When power is transmitted by the first and second spur gears in a state where such a falling phenomenon has occurred, a thrust force parallel to the support shaft is generated on the gear tooth surfaces of the gear teeth of the first and second spur gears. Then, the second spur gear gradually moves along the support shaft, and finally, a self-detachment phenomenon occurs that the gear teeth of the second spur gear are disengaged from the gear teeth of the first spur gear. Such a self-detachment phenomenon also occurs in a gear transmission structure using an internal gear and an external gear.
The present invention relates to a gear transmission structure configured so that transmission and transmission cutoff operations can be performed by sliding operation of a spur gear (an internal gear or an external gear). The purpose is to suppress the self-destroying phenomenon.
[0006]
[Means for Solving the Problems]
According to the feature of the first aspect, the gear tooth surface of the gear tooth of the first spur gear is set in the rotation direction such that the occlusal position side of the gear tooth surface also precedes the separation position side of the gear tooth surface along the rotation direction. Tilted.
Thus, when power is transmitted in a state where the first spur gear is engaged, a thrust force is generated on the inclined gear tooth surface, and the thrust force causes the second flat gear that is slidably operated to engage the second spur gear . Acts to pull back to the position side.
Thus, phenomena fall into the second spur gear is generated to be slid from the second spur gear the first spur gear, attempting to move to the separated position side from the bite position, the thrust force described above, the second flat Movement of the gear to the separated position side is prevented.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows the inside of a transmission case 1 for traveling of a combine, which is an example of a working vehicle, in which the power of an engine (not shown) is transmitted to a hydrostatic continuously variable transmission 2 to perform a gear change operation, The power from the output gear 3 of the hydraulic continuously variable transmission 2 is transmitted to the auxiliary transmission 4 that can freely change the gear into three stages of high, middle and low, and the power from the output shaft 6 of the auxiliary transmission 4 is transmitted to the lower side. It is transmitted to a crawler traveling device (not shown).
[0008]
Next, the auxiliary transmission 4 will be described.
As shown in FIG. 1, an input shaft 5 and an output shaft 6 are arranged, and power from an output gear 3 of a hydrostatic continuously variable transmission 2 is transmitted to the input shaft 5 via an input gear 7. A shift gear member 12 is externally fitted to the input shaft 5 so as to be slidable by a spline structure. A high-speed gear 8, a medium-speed gear 9, and a low-speed gear 10 are fixed to the output shaft 6 in a spline structure. Is biting.
[0009]
With the above-described structure, as shown in FIG. 1, when the shift gear member 12 is slid to the right in the drawing to engage the low-speed gear 13 of the shift gear member 12 with the low-speed gear 10 of the output shaft 6, the power of the input shaft 5 is reduced. Is transmitted to the output shaft 6 at a low speed via the shift gear member 12 and the low speed gear 10. When the middle gear 14 of the shift gear 12 is engaged with the middle gear 9 of the output shaft 6 by sliding the shift gear member 12 in the middle of the page, the power of the input shaft 5 is transmitted to the shift gear member 12 and the middle gear 9. Is transmitted to the output shaft 6 in a medium speed state through
When the shift gear member 12 is slid to the left on the paper surface to engage the internal gear 16 of the shift gear member 12 with the external gear 15 of the output gear 11 as shown in FIG. The power is transmitted to the output shaft 6 at a high speed via the output gear 11 and the high speed gear 8.
[0010]
Next, the relationship between the low-speed gear 13 of the shift gear member 12 and the low-speed gear 10 of the output shaft 6 will be described.
As shown in FIGS. 2 and 3A, the low-speed gear 10 of the output shaft 6 is configured as a spur gear, and an end of the gear teeth 17 of the low-speed gear 10 on the medium-speed gear 9 side (left side in the drawing). 17c is formed in a conical surface. In the forward gear tooth surface 17 a of the gear teeth 17, the side opposite to the medium-speed gear 9 (right side in the drawing) advances ahead of the medium-speed gear 9 side (left side in the drawing) in the forward rotation direction. The forward gear tooth surface 17a is inclined with an inclination angle A (for example, about 40 minutes ± 5 minutes) with respect to the rotation direction (see FIG. 3B).
[0011]
Similarly, on the reverse gear tooth surface 17b of the gear tooth 17, the opposite side (right side in the drawing) of the medium-speed gear 9 precedes the medium-speed gear 9 side (left side in the drawing) in the reverse rotation direction. In addition, the reverse gear tooth surface 17b is inclined with an inclination angle A (for example, about 40 minutes ± 5 minutes) with respect to the reverse rotation direction (see FIG. 3C).
On the other hand, in the gear teeth of the low-speed gear 13 of the shift gear member 12, both the forward gear tooth surface and the reverse gear tooth surface are orthogonal to the forward and reverse rotation directions (FIG. 3A). (A state where the inclination angle A shown in FIG.
[0012]
With the above configuration, when the forward power is transmitted from the hydrostatic continuously variable transmission 2 to the auxiliary transmission 4 in a state where the low speed gear 13 of the shift gear member 12 is engaged with the low speed gear 10 of the output shaft 6. The gear teeth of the low-speed gear 13 of the shift gear member 12 abut against the forward gear tooth surface 17a of the low-speed gear 10 of the output shaft 6, and the low-speed gear 10 of the output shaft 6 is moved as shown in FIGS. As shown, it is driven to rotate in the forward rotation direction.
[0013]
In this case, since the position of the low-speed gear 10 of the output shaft 6 is fixed, the boss 10a (see FIG. 1) is set to be sufficiently long so that the accuracy of the fitting portion between the output shaft 6 and the low-speed gear 10 is improved. The setting is made so that the falling phenomenon does not occur in the low-speed gear 10 of the output shaft 6. As a result, as shown in FIGS. 7 and 3 (b), even if the shift gear member 12 falls down in the above-described state, the medium-speed gear 9, a thrust force is generated on the opposite side (right side of the paper of FIG. 3B), and the thrust force is applied to the shift gear member 12, and the shift gear member 12 is moved to the medium speed gear 9 side (the paper surface of FIG. The self-disengagement phenomenon that moves to the left) is prevented.
[0014]
When the reverse power is transmitted from the hydrostatic continuously variable transmission 2 to the auxiliary transmission 4 in a state where the low-speed gear 13 of the shift gear member 12 is engaged with the low-speed gear 10 of the output shaft 6, the shift gear member 12 The gear teeth of the low-speed gear 13 abut on the reverse gear tooth surface 17 b of the low-speed gear 10 of the output shaft 6, and the low-speed gear 10 of the output shaft 6 moves backward as shown in FIGS. It is driven to rotate in the rotation direction.
Also in this case, as shown in FIGS. 7 and 3 (c), even if the shift gear member 12 falls down as described above, the middle gear face 17b of the low-speed gear 10 of the output shaft 6 has a middle gear. A thrust force is generated on the side opposite to the high-speed gear 9 (rightward on the paper surface of FIG. 3C), and the thrust force is applied to the shift gear member 12, and the shift gear member 12 is moved toward the medium-speed gear 9 (FIG. 3C). Self-disengagement phenomena trying to move to the left) is prevented.
[0015]
Next, the relationship between the internal gear 16 of the shift gear member 12 and the external gear 15 of the output gear 11 will be described.
As shown in FIGS. 1 and 5, an external gear 15 is formed on a lateral side surface of the output gear 11, and a forward gear tooth surface of gear teeth 18 of the external gear 15 as shown in FIG. At 18a, the inclination angle B (to the forward rotation direction is set so that the side opposite to the medium speed gear 9 (left side in the drawing) precedes the medium speed gear 9 side (right side in the drawing) in the forward rotation direction. The forward gear tooth surface 18a is inclined with an angle of, for example, 2 degrees 30 minutes ± 30 minutes (see FIG. 6B).
[0016]
Similarly, in the reverse gear tooth surface 18b of the gear tooth 18, the opposite side (left side in the drawing) of the medium speed gear 9 is arranged to precede the medium speed gear 9 side (right side in the drawing) in the reverse rotation direction. In addition, the reverse gear tooth surface 18b is inclined with an inclination angle B (for example, about 2 degrees 30 minutes ± 30 minutes) with respect to the reverse rotation direction (see FIG. 6C).
[0017]
On the other hand, in the gear teeth 19 of the internal gear 16 of the shift gear member 12, as shown in FIGS. 5 and 6 (a), the gap between the lateral side surface of the shift gear member 12 and the gear teeth 19 is formed. A groove 20 is formed over the entire circumference, and the gear teeth 19 are slightly separated from the lateral side surface of the shift gear member 12. In the gear teeth 19, both the forward gear tooth surface and the reverse gear tooth surface are orthogonal to the forward and reverse rotation directions (the state in which the inclination angle B shown in FIG. 6A is zero).
[0018]
With the above configuration, in a state where the internal gear 16 of the shift gear member 12 is engaged with the external gear 15 of the output gear 11, the forward power is transmitted from the hydrostatic continuously variable transmission 2 to the auxiliary transmission 4. 5 and 6 (b), the gear teeth 19 of the internal gear 16 of the shift gear member 12 come into contact with the forward gear tooth surface 18a of the external gear 15 of the output gear 11, and The output gear 11 is driven to rotate in the forward rotation direction.
[0019]
In this case, since the output gear 11 has a fixed position, the boss 11a (see FIG. 1) is set to be sufficiently long, and the accuracy of the fitting portion between the input shaft 5 and the output gear 11 is set to be high. The output gear 11 is prevented from falling down. Thus, even if the shift gear member 12 falls down in the above-described state, the forward gear tooth surface 18a of the external gear 15 of the output gear 11 is on the opposite side to the medium speed gear 9 (FIG. 6B). , A thrust force is generated on the shift gear member 12, and the shift gear member 12 tends to move toward the medium-speed gear 9 (to the right in FIG. 6B). Is prevented.
[0020]
When the reverse power is transmitted from the hydrostatic continuously variable transmission 2 to the auxiliary transmission 4 in a state where the internal gear 16 of the shift gear member 12 is engaged with the external gear 15 of the output gear 11, FIG. As shown in FIG. 6C, the gear teeth 19 of the internal gear 16 of the shift gear member 12 abut against the reverse gear tooth surface 18b of the external gear 15 of the output gear 11, and the output gear 11 is It is driven to rotate in the reverse rotation direction.
Even in this case, as described above, even if the shift gear member 12 falls down, the reverse gear tooth surface 18b of the external gear 15 of the output gear 11 is placed on the opposite side of the medium speed gear 9 (leftward on the paper). ) Is generated, the thrust force is applied to the shift gear member 12, and the shift gear member 12 is prevented from moving toward the medium-speed gear 9 (to the right in FIG. 6C). .
[0021]
In the internal gear 16 of the shift gear member 12, a groove 20 is formed over the entire circumference, and the gear teeth 19 are slightly separated from the lateral side surface of the shift gear member 12. As a result, as shown in FIGS. 5 and 3 (b) and (c), the gear teeth 19 of the internal gear 16 are shifted from the gear teeth 18 of the external gear 15 by the gear teeth surfaces 18a and 18b of the forward and reverse gears. The shift gear member 12 is brought into contact with the middle speed gear 9 so that the thrust force on the opposite side (left side in the drawing) from the middle speed gear 9 is reliably applied to the shift gear member 12.
[0027]
【The invention's effect】
According to the features of claim 1, the sliding operation of the spur gear, in the produced gear transmission structure to allow transmission and transmission blocking operation, it is possible to suppress the self-removal phenomenon from the occlusal position of the spur gear to be slid As a result, the reliability and durability of power transmission in the gear transmission structure can be improved.
In this case, it is possible to suppress the self-removal phenomenon only by performing processing to incline the gear tooth surface of the gear teeth a little, and it is not necessary to separately provide a special device for suppressing the self-removal phenomenon. It is advantageous in terms of.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view of a subtransmission in a low speed state. FIG. 2 is a perspective view of gear teeth of a low speed gear on an output shaft. FIG. 3 is a view of gear teeth of a low speed gear on an output shaft and low speed gears on a shift gear member. FIG. 4 is a plan view showing a state in which the sub-transmission is engaged with the gear teeth at a high speed. FIG. 5 is an engagement state between the external gear of the output gear on the input shaft and the internal gear of the shift gear member. and the external gear of the output gear in a vertical sectional side view and FIG. 6 input shaft showing a vertical sectional side shows the phenomenon collapse of a plan view and FIG. 7 shift gear member showing the occlusion of the internal gear of the shift gear member Figure [code Description ]
10 First spur gear 13 Second spur gear 15 External gear 16 Internal gear 17 Gear teeth 17a, 17b of first spur gear Gear tooth surface 18 of gear teeth of first spur gear 18 Gear teeth 18a, 18b of external gear Gear tooth surface 19 of the gear tooth of the external gear Gear tooth of the internal gear

Claims (1)

With a first spur gear and a second spur gear,
Over an occlusal position where the gear teeth of the second spur gear engage with the gear teeth of the first spur gear, and a separation position where the gear teeth of the second spur gear separate from the gear teeth of the first spur gear; A gear transmission structure in which the second spur gear is configured to be slidable in the axial direction,
The first spur gear is constituted by a single spur gear provided with a boss into which a shaft for supporting the first spur gear is inserted, and the length of the boss in the axial center direction is defined by the first spur gear. The second spur gear is configured to be longer than the gear teeth width of the spur gear, and the second spur gear is constituted by one of an integrated multi-stage gear in which a plurality of parallel spur gears having a common rotation axis are adjacent to each other; The gear tooth surface of the second spur gear is formed on a surface parallel to the rotation axis,
A gear transmission in which a gear tooth surface of the first spur gear is inclined with respect to the rotation direction such that an occlusal position side of the gear tooth surface precedes a separation position side of the gear tooth surface in a rotation direction. Construction.

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