JP2001027320A - Linear shift type shift operation device - Google Patents

Abstract

(57) [Problem] To reduce the cost of a shift operation device provided with a shift drum and reduce the cost, and to maintain an accurate shift position. SOLUTION: A ring-shaped shift drum 30 is pivotally mounted on a side portion in a transmission case 12, and one of the bent portions is bent in a circumferential direction on a surface of the shift drum 30 in accordance with a required movement amount of shift arms 37 and 38. In addition to providing the guide groove 39,
A detent hole 50 for holding a shift position is provided. Then, the engagement bosses 37 b and 38 b of the shift arm are engaged with the guide grooves 39. A steel ball 51 is arranged on the inner surface of the cover 26, and the steel ball 5 is
1 is pressed to make contact with the surface of the shift drum 30. When the shift drum 30 rotates, the bending of the guide groove 39 causes the shift arms 37, 38 to swing and shifters 35, 36
Moves to the shift position, and the steel ball 51 engages with the detent hole 50 to stop the rotation of the shift drum 30 to maintain the shift position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear shift type shift operating device, and more particularly to a linear shift type shift operating device for a work vehicle such as an agricultural tractor or a riding control machine.

[0002]

2. Description of the Related Art In a working vehicle such as an agricultural tractor or a riding management machine, an operation pattern of a shift lever for switching a transmission is not only an H-shaped pattern for shifting back and forth and left and right, but also a straight line in a vertical or front and rear direction. 2. Description of the Related Art There is known a linear shift type speed change operation device that shifts dynamically. The linear shift type shift operation device is an electronic type that electrically detects the operation of the shift lever and moves the shifter, or the operation of the shift lever is transmitted to the shift drum by a link mechanism, and the shift drum is rotated to shift. There is a mechanical type that moves a shifter through an operating piece such as an arm.

[0003] In the above-mentioned mechanical speed change device, a shift drum is formed of solid cylindrical steel material, and an end mill or the like is provided on the surface of the shift drum in accordance with the number of operating pieces such as a shift arm for moving a shifter. A plurality of guide grooves are provided in the circumferential direction by machining, and the operating pieces are engaged with the respective guide grooves. Each guide groove is bent in the width direction of the shift drum in accordance with the amount of movement required for each operating piece to switch the shift position at the time of a shift operation, and if the shift drum rotates due to movement of the shift lever. The respective operating pieces move along the bending of the guide grooves. Then, the shifter slides on the shifter stay by the movement of the operation piece, and the gear combination of the transmission is switched to another shift position.

[0004]

In a conventional mechanical shift operation device, a shift drum is formed of solid steel material, and a guide groove is machined on a surface of the shift drum by an end mill or the like. Costs and processing costs were high. Further, since the pressure angle when moving the operating piece is limited to about 30 degrees, the diameter of the shift drum increases as the moving amount of the operating piece increases, and a plurality of guide grooves are provided. In addition, the width of the shift drum must be increased. Therefore, the weight of the shift drum increases and a large installation space is required. Also, in order to hold the shift position, a detent groove is provided in the shifter stay where the shifter slides, but if there is a variation in parts, the phase of the shift drum and the detent position of the shifter stay are shifted, The correct shift position cannot be maintained.

[0005] In view of the above, there is a technical problem to be solved in order to reduce the cost of the shift operation device having the shift drum and reduce the cost, and to maintain an accurate shift position. The purpose is to solve this problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object. A ring-shaped shift drum is rotatably pivoted in a transmission case, and a circumferential direction of the shift drum surface is provided. A guide groove bent in accordance with a necessary movement amount of the shifter or the operation piece for moving the shifter is provided, and the operation piece for moving the shifter or shift is engaged with the guide groove from above and below, and the shift drum is A linear shift type transmission in which the shift groove or the operating piece for moving the shifter is formed to move to the respective shift position by the guide groove when rotated, and the shift drum is provided with a locking portion for holding a shift position. An operation device, and a linear shift provided on a side of a transmission case by integrally unitizing the shift drum and a shifter or an operation piece for moving the shifter. There is provided a speed change device.

[0007]

An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a small passenger management machine 10 as an example of a work vehicle, which has a space between an engine 11 and a transmission case 12, and a spacer housing 13 made of steel is interposed in this space. . A drive transmission shaft 14 is provided in the spacer housing 13, and the power of the engine 11 is transmitted to the transmission case 12 via the drive transmission shaft 14. Then, two rear wheels 15, or four rear wheels 15, 15 and front wheels 16, 16 are driven via a transmission in the transmission case.

A shift lever 18 for main shifting is provided on the side of the driver's seat 17. A base end of the shift lever 18 is fixed to an arm 20 pivotally attached to a cylinder head 19 above the transmission case 12. The shift lever 18 is rotatable in the front-rear direction to form a linear shift type operation pattern. Further, a shift drum 30 described later is provided in the transmission case 12, and one end of a transmission shaft 21 for rotating the shift drum 30 protrudes from a side surface of the transmission case 12. The transmission shaft 21
, A lever 22 protrudes rearward, and the lever 22 and the arm 20 are connected by a link rod 23. Therefore, when the shift lever 18 is rotated in the front-rear direction, the speed change shaft 21 rotates around the axis.

As shown in FIGS. 2 to 5, an opening 25 is provided on the side of the transmission case 12, and
The cover 26 is fixed to 5. The cover 26 has an accommodating portion 26a that bulges outward, and a shaft support portion 26b is provided inside the cover 26 to support the support shaft 33 of the shift drum 30. The shift drum 30 is housed in the space with the opening 25.

The shift drum 30 is formed by previously forming a guide groove 39 and detent holes 50, 50... Described later in a steel plate, and rolling the steel plate into a cylindrical shape.
A hollow shaft 31 is fixedly mounted at the center of the shift drum 30, and a hollow bevel gear 32 is fitted to one end of the hollow shaft 31. A support shaft 33 is slidably penetrated through the hollow shaft 31, and both ends of the support shaft 33 are fixed to a shaft support 26 b of the cover 26. The hollow shaft 31 and the support shaft 33 are provided such that their axes are in the front-rear direction of the transmission case 12 (the front-rear direction of the body).

On the other hand, the transmission shaft 21 has its axis centered in the left-right direction of the transmission case 12 (left-right direction of the body).
A bevel gear 24 is fixedly mounted near the other end of the transmission shaft 21.
4 meshes with the bevel gear 32 of the hollow shaft. A groove 27 for shim adjustment is provided at an intermediate portion of the transmission shaft 21, and a shim 28 is fitted in the groove 27. When backlash occurs between the bevel gear 24 and the bevel gear 32, it is necessary to adjust the position of one of the bevel gears. There is a possibility that the engagement bosses 37b and 38b of the shift arm may be displaced from a proper position.

For this reason, the shim 28 fitted in the groove 27
By inserting a new shim inside the bearing (on the bearing side) and slightly shifting the transmission shaft 21 to the outside of the transmission case 12, the bevel gear 24 approaches the bevel gear 32 and the shim on the transmission shaft 21 side is adjusted. The backlash between the bevel gear 24 and the bevel gear 32 can be eliminated, and the displacement of the guide groove 39 of the shift drum 30 can be prevented. Note that the transmission shaft 2
The one-side bevel gear 24 does not necessarily have to be provided over the front circumference, but may be formed only with a portion necessary for rotating the hollow-shaft bevel gear 32 once. Further, for convenience of description, the description of the transmission shaft 21 is omitted in FIGS. 3 and 4.

A shifter stay 34 is disposed outside the shift drum 30 in the front-rear direction of the transmission case 12.
At least two shifters for switching the gear combination of the transmission to another shift position are provided. In the present embodiment, two shifters 35 and 36 are slidably fitted to the shifter stay 34. Further, shift arms 37, 38, which are operating pieces for moving the shifters 35, 36, are provided, and pivot points 37a, 38a of the respective shift arms 37, 38 are separated outside the shift drum 30 and from the shifters 35, 36. It is provided in the position where it was done. Each shift arm 37, 38
Are provided with engaging bosses 37b and 38b at an intermediate portion thereof.

On the other hand, on the surface of the shift drum 30,
One guide groove 39 is provided along the circumferential direction, and the engaging bosses 37b and 38b of the shift arm are engaged from above and below the guide groove 39. The guide groove 39 is bent corresponding to the amount of movement required for the shift arms 37, 38 to move the shifters 35, 36 to switch the shift position. On the surface of the shift drum 30, detent holes 50, 50,... Are provided on both sides of the guide groove 39 as locking portions for holding the shift position.

The detent holes 50, 50,...
9 is provided on both the front side and the rear side of the fuselage,
The cover 26 is provided with holes 52, 52 for accommodating steel balls 51, 51 for detent, corresponding to the pitch of the detent holes 50, 50 in the front-rear direction. The position of the detent holes 50, 50 in the circumferential direction is determined by rotating the shift drum 30 by operating the shift lever 18 and engaging the engaging bosses 37b, 38 of the shift arm, as described later.
When b moves to a predetermined position necessary for switching the positions of the shifters 35 and 36, one of the detent holes 50
Are set to exactly face the holes 52 of the cover 26.

Then, bolts 53, 53 are screwed into the respective holes 52, 52 from outside the cover 26, and
Springs 54, 54 are interposed between the tips of the steel balls 51, 51 and the steel balls 51, 51. Therefore, the steel balls 51, 51 are constantly pressed against the surface of the shift drum 30 by the springs 54, 54, and the shift drum 30 rotates to engage the engaging boss 37 of the shift arm.
When any one of the detent holes 50 is moved to a predetermined position necessary for switching the shift position, one of the detent holes 50 faces the hole 52 of the cover 26, and the steel ball 51 pressed by the spring 54 moves the shift drum. Engage with 30 detent holes 50.

Thus, the rotation of the shift drum 30 is locked, and the shift position of the shift lever 18 is maintained. When the shift lever 18 is strongly operated to another shift position, the shift drum 30 rotates and the steel ball 51 is pressed against the pressing of the spring 54.
Is pushed back into the hole 52, the shift drum 30 rotates again, and the engagement bosses 37b and 38b of the shift arm move to another shift position.

Although not shown, a projection is provided at a predetermined position on the surface of the shift drum 30 and a recess is provided inside the cover 26 as a locking portion for holding the shift position. Shift drum 30 by operation
Is rotated, and when one of the engagement bosses 37b and 38b of the shift arm moves to a predetermined shift position, one of the protrusions engages with the recess to lock the rotation of the shift drum 30. Is also good.

Here, the shift drum 30 is formed by cutting a guide groove 39 and detent holes 50, 50... From a steel plate in advance and then rolling the steel plate into a cylindrical shape.
The step of end milling a cylindrical steel material as in a conventional shift drum is not required, and material costs and processing costs can be reduced. Also, the shift drum 30 and the shift arms 37, 3
8 and the shifters 35 and 36 are integrally unitized and provided on the side of the transmission case 12, so that the number of parts is small and the configuration is compact.

When the shift lever 18 of the driver's seat 17 is operated, the transmission shaft 21 rotates through the link rod 23, and the bevel gear 24 and the bevel gear 32 are rotated.
, The hollow shaft 31 and the drum 30 rotate about the support shaft 33. At this time, since the engagement bosses 37b and 38b of the shift arm move following the bending of the guide groove 39, the shift arms 37 and 38 swing about the respective pivot points 37a and 38a, and The shifters 35 and 36 engaged with the tip portions 37c and 38c move in the front-rear direction of the transmission case 12 along the shifter stay 34, and the gear combination of the transmission is switched to another shift position.

FIGS. 6 to 8 show the movement of the guide groove 39 provided on the surface of the shift drum 30, the shift arms 37, 38 and the shifters 35, 36. The guide groove 39 extends along the center line L of the shift drum. When the engagement bosses 37b and 38b of the shift arm are located on the center line L, the shift arms 37 and 38 are in the vertical posture, and the transmission 40 is in the neutral position. Then, at a position where the guide groove 39 is bent to the left or right of the center line L, the shift arm 37 or 38 swings to the left or right in the drawing, and the transmission 40 switches to any of the shift positions. . One engagement boss 37b is in the neutral position of the guide groove 39
(N), the other engaging boss 38b is also at the neutral position (N ₁ ) of the guide groove, and both shift arms 37 and 38 are in the vertical posture, and the two shift rings 41 of the transmission 40 are , 42 are in a neutral state.

When the shift lever 18 is operated to the first speed, the shift drum 30 rotates to move one engagement boss 37b to the first speed position (1) of the guide groove 39,
The engagement boss 37b moves to the left of the center line L, and the lower end 37c of one of the shift arms swings leftward in the drawing. At this time, the other engagement boss 38b moves to the neutral position (N ₂ ) along the center line L of the guide groove 39, so that the other shift arm 38 maintains the vertical posture. That is, one shifter 35 moves leftward in the drawing (frontward of the fuselage), the shift ring 41 meshes with the first speed gear 43, and the other shifter 3
6 does not move, so that the shift ring 42 maintains the neutral position. Therefore, the transmission 40 is shifted to the first speed. Further, since any one of the steel balls 51 engages with any one of the detent holes 50, the shift drum 30
Is locked, and the shift position of the transmission 40 is shifted to the first position.
Will be kept fast.

The detent holes 50 are provided on both sides of the guide groove 39. When the guide groove 39 is bent leftward in the drawing, it is provided on the right side of the guide groove 39. Where the groove 39 is bent rightward in the figure, it is provided on the left side of the guide groove 39. On the other hand, when the detent holes 50, 50,... Are provided only on the left side of the guide groove 39, the detent hole 50 is too close to the guide groove 39 at the place where the guide groove 39 is bent leftward, so that the shift drum If the detent hole 50 is moved away from the bent portion of the guide groove 39 in order to avoid a crack on the surface of the shift drum 30, the width of the shift drum 30 must be extremely widened and the shift drum 30 becomes large. Becomes As shown in the figure, the detent holes 50 are provided at positions opposite to the bending direction on both sides of the guide groove 39, so that the detent holes 50 are separated from the guide groove 39 by a necessary distance and approach the center line L of the shift drum. Detent hole 5 in position
., And the width of the shift drum 30 can be made as small as possible.

Next, when the shift lever 18 is operated to the second speed, the shift drum 30 rotates to move one engagement boss 37b to the second speed position (2) of the guide groove 39,
The engagement boss 37b moves to the right of the center line L, and the lower end 37c of one of the shift arms swings rightward in the drawing. At this time, the other engagement boss 38b moves to the neutral position (N ₃ ) along the center line L of the guide groove 39, so that the other shift arm 38 maintains the vertical posture. That is, one shifter 35 moves rightward in the drawing (rearward of the fuselage), the shift ring 41 meshes with the second speed gear 44, and the other shifter 3
6 does not move, so that the shift ring 42 maintains the neutral position. Therefore, the transmission 40 is shifted to the second speed. In such a case, either one of the steel balls 51 is engaged with any one of the detent holes 50, so that the rotation of the shift drum 30 is locked, and the shift position of the transmission 40 is maintained at the second speed. Is done.

The engaging boss 37b is connected to one of the guide grooves 39.
The shift arm 37, 38 and the shifters 35, 36 simultaneously move to the neutral position during the shifting operation because the gear shifts from the speed position (1) to the second speed position (2) through the center line L of the shift drum. There is a position, and the transmission changes to the second gear once through the neutral state. Further, at a slightly forward position of the second speed, one engagement boss 37b has a neutral position (N ₄ ), and the other engagement boss 38b has a position at the same time as the neutral position (N ₅ ). . In this state, both the shift arms 37 and 38 and the shifters 35 and 36 are simultaneously in the neutral position, and the transmission 40 is temporarily in the neutral state.

When the shift lever 18 is operated to the third speed, the shift drum 30 rotates and the other engagement boss 38b moves to the third speed position (3) of the guide groove 39, and The joint boss 38b moves to the left of the center line L, and the lower end 38c of the other shift arm swings leftward in the drawing. At this time, the one engagement boss 37b moves to the neutral position (N ₆ ) along the center line L of the guide groove 39, so that the one shift arm 37 holds the vertical posture. That is, the other shifter 36 moves to the left in the drawing (to the front of the aircraft) and the shift ring 42 meshes with the third speed gear 45, and the one shifter 35 does not move, so that the shift ring 41 maintains the neutral position. . Therefore, the transmission 40 is shifted to the third speed.

Further, when the shift lever 18 is operated to the fourth speed, the shift drum 30 rotates and the other engaging boss 38b moves to the fourth speed position (4) of the guide groove 39,
The engagement boss 38b moves to the right of the center line L, and the lower end 38c of the other shift arm swings rightward in the drawing. At this time, the one engagement boss 37b moves to the neutral position (N ₇ ) along the center line L of the guide groove 39, so that the one shift arm 37 holds the vertical posture. That is, the other shifter 36 moves rightward in the drawing (rearward in the figure), the shift ring 42 meshes with the fourth speed gear 46, and the one shifter 3
5 does not move, so that the shift ring 41 maintains the neutral position. Therefore, the transmission 40 is shifted to the fourth speed.

The engaging boss 38b is connected to the guide groove 39-3.
Since the gear shifts from the speed position (3) to the fourth speed position (4) through the center line L of the shift drum, both the shift arms 37 and 38 and the shifters 35 and 36 simultaneously reach the neutral position during the shifting operation. There is a position and the transmission switches to fourth gear once through a neutral state. Also, when the transmission 40 is in the above-described neutral position, or when the transmission is shifted to the third speed or the fourth speed, one of the steel balls 51 is used.
Engages with any one of the detent holes 50, the rotation of the shift drum 30 is locked, and the shift position of the transmission 40 is maintained.

As described above, the ring type shift drum 30
In one guide groove 39 provided in the. By swinging the two sets of shift arms 37 and 38, the shifters 35 and 36 move linearly, and the transmission is switched. Since the engagement bosses 37b and 38b that engage with the guide groove 39 are provided at the intermediate portion of the shift arm, the engagement boss 3 due to bending of the guide groove 39
7b and 38b move to the tip portions 37c and 3 of the shift arm.
8c, the shifters 35 and 36 are largely moved, and a sufficient moving amount necessary for the gear shifting operation can be secured. Therefore, the bending angle of the guide groove 39 can be reduced, and the diameter of the shift drum 30 can be reduced.

Since the detent holes 50 are provided on the surface of the shift drum 30, the guide grooves 39 are provided.
, And the detent holes 50, 50... Can be die-cut, and the detent holes 50, 50.
The relative positions of 0 and 50 do not shift, and the detent position can be accurately maintained.

Further, the guide groove 39 is provided with a plurality of positions at which the transmission is in a neutral state, and each shift arm 37, 38 and the shifters 35, 36 have a position at which they are simultaneously at the neutral position. Therefore, the shift drum 30
When the gears rotate to move the shifters 35 and 36, there is no danger that the gears on the first and second speeds and the gears on the third and fourth speeds may be disengaged at the same time.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0033]

As described in detail in the above embodiment, the invention according to claim 1 is provided with one guide groove on the surface of a ring-shaped shift drum, and the shifter is rotated by rotation of the shift drum. Alternatively, since the operating piece for moving the shifter is moved, the diameter of the shift drum can be reduced without increasing the bending of the guide groove, and the configuration of the shift operation device can be reduced in size. In addition, since the shift drum is provided with a locking portion for holding the shift position, unlike the conventional type in which the detent groove is provided in the shifter stay, the phase of the shift drum and the detent position of the shifter stay do not shift. The detent position can be held accurately.

According to a second aspect of the present invention, the shift drum and the shifter or the operating piece for moving the shifter are integrally unitized and provided on the side of the transmission case, so that the shifting operation device can be easily assembled and maintained. Can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a passenger management machine according to an embodiment of the present invention.

FIG. 2 is a front view of the inside of a transmission case showing a shift drum and a shift arm.

FIG. 3A is a side view of a cover fixed to an opening of a transmission case. (b) is a side view showing an opening provided in the mission case.

FIG. 4 is a perspective view of an inner surface of a cover to which a shift drum is attached.

FIG. 5 is a partially cutaway plan view of a shift drum and a transmission shaft.

FIG. 6 is an explanatory view showing movement of a shift arm from a neutral position to a second speed position, with guide grooves and detent holes of a shift drum.

FIG. 7 is an explanatory view showing a guide groove and a detent hole of a shift drum and a movement of a shift arm from a neutral position to a fourth speed position.

FIG. 8 is a longitudinal sectional side view of the transmission showing movements of a shift arm and a shifter.

[Explanation of symbols]

 12 Transmission Case 18 Shift Lever 25 Opening 30 Shift Drum 35, 36 Shifter 37, 38 Shift Arm 39 Guide Groove 40 Transmission 50 Detent Hole 51 Steel Ball

Claims (2)

[Claims] 1. A ring-shaped shift drum is rotatably pivotally mounted in a transmission case, and is bent in accordance with a movement amount necessary for a shifter or an operation piece for moving the shifter in a circumferential direction of the shift drum surface. The guide groove is provided, and the shifter or the operation piece for moving the shift is engaged with the guide groove from above and below. When the shift drum rotates, the guide groove causes the shifter or the operation piece for moving the shifter to shift. A linear shift type speed change operation device characterized in that the shift drum is formed so as to move to a position, and the shift drum is provided with a locking portion for holding a shift position. 2. The linear shift type speed change operation device according to claim 1, wherein the shift drum and the shifter or an operation piece for moving the shifter are integrally unitized and provided on a side portion of a transmission case.