JP2007120691A - Transmission for tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable three-stage speed change or four-stage speed change, while reducing the number of speed change gears by simplifying the main transmission gear mechanism, and to reduce cost. <P>SOLUTION: The main transmission gear mechanism 1 capable of executing speed change of several stages, in other words, a first stage to a third stage or the first stage to a fourth stage, consists of several stages of transmission gears (4b, 4c), (5b, 5c), (6b, 6c) capable of gearing transmission which are provided in between a transmission shaft 2 and a counter shaft 3 which are parallel and a normally intermeshing gear transmission part 7, provided at a position from the transmission shaft 2 and the counter shaft 3 for transmitting speed change rotation of the counter shaft 3 to an auxiliary speed change counter shaft 11. In this case, one of the several transmission stages can be provided, by extending a clutch claw 8 at the normally intermeshing gear transmission part 7 and intermeshing it with the main speed change clutch claw 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement in a transmission for a tractor and belongs to the technical field of agricultural machinery.

Conventionally (for example, refer to Patent Document 1), in a change form of a 4-speed shift from 1st speed to 4th speed, it is usual to change by installing 4 to 8 transmission gears.
Further, as disclosed in Patent Document 2, in the case of a three-speed shift (1st to 3rd speed), it is constituted by 3 to 6 transmission gears.
JP-A-10-203189 JP-A-10-193993

  An object of the present invention is to reduce the number of transmission gears by simplifying the main transmission gear mechanism, thereby enabling a three-speed shift or a four-speed shift, thereby reducing costs.

In order to solve the above problems, the present invention has taken the following technical means.
That is, according to the present invention, the transmission shaft (2) and the counter shaft which are parallel to each other in the main transmission gear mechanism (1) capable of shifting in several stages of 1st to 3rd speed or 1st to 4th speed. (3) It consists of several speed change gears (4b, 4c), (5b, 5c), (6b, 6c) installed between them and capable of meshing transmission. From the transmission shaft (2) to the counter shaft (3) A constant meshing gear transmission (7) is provided on the way to transmit the speed change of the counter shaft (3) to the auxiliary transmission countershaft (11), and the constant meshing gear transmission (7) has a clutch pawl (8 ) Is extended and meshed with the main transmission clutch pawl (9), so that one of the several speeds can be obtained.

  By utilizing the existing constant meshing gear transmission (7) on the auxiliary transmission side and engaging the clutch pawl (8) provided thereto with the main transmission clutch pawl (9), for example, 1st to 4th speed In the case of the four-speed shift, a shift of “three speeds” which is one of the shift speeds can be obtained, and the main shift four-speed shift can be performed by three pairs of six gears. The cost is reduced by 2 gears.

  In short, according to the present invention, since four gears and four gears usually require eight gears in four pairs, three pairs of six gears are sufficient, so the configuration is simplified. , A significant cost reduction can be achieved.

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a riding tractor. An engine E is mounted on the front of the tractor T, and the rotational power of the engine E is used as a main / sub transmission gear mechanism (main / sub transmission gear mechanism 20). The transmission is transmitted to the front wheels 21 and the rear wheels 22 by transmitting the rotational power decelerated by the main / sub transmission. A hydraulic cylinder case 23 is provided in the upper part of the mission case 20, and a lift arm 24 is pivotally attached to the hydraulic cylinder case 23. When the hydraulic oil is supplied into the hydraulic lift cylinder 25 in the hydraulic cylinder case 23, the lift arm 24 is turned up, and when discharged, the lift arm 24 is lowered.

  The lift arm 24 and the lower link 26 are connected by a lift rod 27, and a work machine such as a rotary mounted on the lower link 26 is moved up and down by the lifting and lowering drive of the lift arm 24. .

The steering handle 28 has a configuration in which the left and right front wheels 21 are steered left and right by left and right turning operations, and a driver seat 29 is provided behind the steering handle 28.
FIG. 2 shows a power transmission path diagram of the tractor traveling system. The rotational power of the engine E is obtained by switching the main clutch 31 that is intermittently operated by the operation of the main clutch pedal 30, a four-speed shift (main shift 1st speed to 4th speed). ) And the sub-transmission 10 capable of shifting in multiple stages, and the rotational power decelerated by the main transmission 1 and the sub-transmission 10. Is transmitted through a pinion bevel gear shaft 32 to a rear wheel differential device 33 provided at the rear of the transmission, and is transmitted to a rear wheel 22 through a final reduction gear mechanism.

  The drive shaft 34 extending from the rear wheel differential device 33 to the left and right is provided with a brake device including a brake disk 35 and a brake actuator 36, etc., and brakes are performed via the brake actuator 36 by operating the left and right brake pedals 37L and 37R. The disc 35 is crimped to brake the left rear wheel or the right rear wheel of the left and right rear wheels 22.

  Rotational power to the front wheel 21 branched from the drive pinion shaft 32 is transmitted to the front wheel differential device 40 via the front wheel transmission shaft 38 and the 4WD switching clutch 39 in the form of a multi-plate clutch, and drives the left and right front wheels 21, 21. It is supposed to be. Further, the PTO driving force is taken out via the PTO clutch and the PTO transmission, via the PTO transmission shaft 40, to the PTO shaft 41 protruding rearward from the back portion of the transmission mission case 20.

  FIG. 3 shows an example of the configuration of the main transmission (main transmission gear mechanism) 1 in the case of four-speed transmission. This main transmission gear mechanism 1 is coaxial with the drive pinion shaft 32 as shown in FIG. A cylindrical counter shaft 2 provided on the input shaft 3 and an input transmission shaft 3 as a PTO transmission shaft. Of these, the input transmission shaft 3 is provided integrally with the input gear 13 to be described later, and a transmission shaft 14 having a wide clutch pawl 14a is rotatably fitted at a position away from the appropriate distance, and further, between the appropriate distances. The first and second speed transmission gears 4b and 5b are provided with clutch pawls 4a and 5a, respectively, and are loosely fitted to the transmission shaft 14 part. On the other hand, on the lower side of the wide clutch pawl 14a, a fourth speed transmission shaft 6b and a constant mesh transmission shaft 7b provided with clutch pawls 6a and 7a are connected to the input transmission shaft 3, the third speed transmission shaft 7, and the fourth speed, respectively. The transmission shaft 6 is loosely fitted in order.

  The clutch pawls 4a, 5a, 6a and 7a provided before and after the clutch pawl 14a are all provided with the same diameter, and as the main transmission clutch pawl 9 provided with two ridge clutch portions slides, The rotation of the transmission shaft 14 can alternatively be transmitted to the first, second, and fourth transmission gears 4b, 5b, 6b and the constantly transmitting gear 7b.

  On the other hand, on the counter shaft 2 side, a first speed counter gear 4c meshing with the first speed gear 4b and a second speed counter gear 5c meshing with the second speed gear 5b are integrally provided by spline fitting, respectively. On the rear end side of the cylindrical countershaft 2, a fourth speed counter gear 6c and a transmission gear 7c for transmitting the speed change rotation of the countershaft 2 to the countershaft 11 of the subtransmission unit are provided by integral molding.

  Accordingly, the transmission transmission rotation from “first speed” to “fourth speed” is applied to the counter shaft 2 by the selective sliding of the clutch pawl 9. For example, when one of the main transmission clutch 9 and the first speed clutch pawl 4a are engaged, the transmission shaft 14 rotation is transmitted to the first speed transmission shaft 4, and the counter gear 4c is interlocked. ”. The rotation of the counter shaft 2 is transmitted to the transmission gear 7c and the constantly meshing transmission gear 7b, and the auxiliary transmission counter shaft 11 integrated therewith is interlocked.

  The “third speed” is performed by meshing one of the main transmission clutches 9 with the clutch pawl 7 a so that the rotation of the transmission shaft 14 is transmitted to the auxiliary transmission counter shaft 11 as it is.

  As described above, a pair of first-speed transmission gears 4b, 4c capable of meshing transmission that are installed between the shafts 2 and 3, a pair of second-speed transmission gears 5b, 5c capable of meshing transmission, and a pair of meshing transmission capable of transmission. A clutch pawl 7a is extended to the shaft 3 side transmission gear 7b, out of the constantly meshing transmission gears 7b, 7c provided on the way from the shaft 2 to the shaft 3 and comprising the fourth speed transmission gears 6b, 6c. In addition, by engaging the clutch pawl 7a with the main transmission clutch pawl 9, a "third speed" gear stage can be obtained. In other words, the constantly meshing transmission gear 7 is configured so as to substitute for the “third speed” gear. Accordingly, the "first speed" shift stage is obtained by the engagement of the main transmission clutch pawl 9 and the first speed transmission gears 4b and 4c, and the "second speed" is achieved by the engagement of the main transmission clutch pawl 9 and the second speed transmission gear 5b. "Gear stage" is obtained, and the "fourth speed" gear stage is obtained by meshing the main transmission clutch pawl 9 with the fourth speed transmission gear 6b, and the "third speed" gear stage is the main gear clutch. It is obtained by meshing between the claw 9 and the clutch claw 7a of the constant meshing gear transmission 7 and is transmitted to the auxiliary transmission countershaft 11 from this.

  Rotational power from the engine E to the main transmission 1 is transmitted to the shaft 3 through the input transmission shaft 12, the input gear 13, and the transmission gear 14 that always meshes with the input gear 13, and each transmission gear from the shaft 3 to the shaft 2. Power is transmitted through 4b, 5b, 6b and the like.

  The embodiment shown in FIGS. 4 and 5 is a tractor equipped with a front wheel speed increasing device and an automatic braking device, a first stage metal 45 having a main relief valve and a pressure reducing valve, and a second stage having a front wheel speed increasing valve. The metal 46 and the third-stage metal 47 having a built-in brake valve are arranged in three stages. In the case where the three valves are separately arranged, it is necessary to connect them with hydraulic piping, which is disadvantageous in terms of cost and hydraulic circuit. In this example, depending on the model, it is possible to selectively use a specification used in one stage, a specification used in two stages, and a specification used in three stages. Also, the oil passages 48 (4WD ports), 49 (front wheel acceleration ports), and 50 (braking ports) can be machined in the transmission case 20 directly from the first-stage metal mounting portion toward the actuator. The hydraulic piping can be eliminated.

  6 to 9, in the 2P link bracket of a tractor having a horizontal control function, when a 3P link is optionally attached to a 2P link specification tractor, the configuration can be attached without removing the 2P parts. It is said.

  In short, FIG. 6 and FIG. 7 show a state in use with the 2P link, and the 2P link bracket 51 integrates the base plate 52, the support pins 53 provided in the left and right protruding shapes, and the frame portion 54 holding the support pins 53. These are fixed to the rear surface of the transmission case by four bolts 55, 55. A rotation guide body 56 is interposed between the base plate 52 and the transmission case, and is provided so as to be rotatable around a horizontal axis when the bolt is removed.

  A rotation angle detection sensor 57 is provided on the upper part of the bracket 51, and a mud-proof cover 58 is attached so as to cover them. The sensor 57 is mounted and supported by a sensor mounting stay 62 and a support stay 63, and the cover 58 is fastened and fixed by the top link bracket mounting bolt 64.

8 and 9 show the state when the 3P link option is attached, but the 2P link bracket 54 can be bolted at a position rotated 90 degrees. A top link bracket 60 as a part for attaching the 3P link can be detachably attached to the rear portion of the vehicle body of the tractor via a mounting plate 61 and a mounting bolt 64.
The top link bracket 51 for the 3P link is fastened together with the mounting bolt 59 of the cover 58 and fixed at a position where it is laid under the cover.

  Conventionally, there are many market demands for recombination of 2P links to 3P links, and it is set as an option, but 2P link parts must be removed from the tractor, and recombination takes a lot of man-hours. In this example, the 2P bracket and the angle detection sensor can be rearranged to 3P without being removed. The cover that protects the sensor from mud or the like can be attached again from above the 3P top link bracket, and the 3P top link bracket sandwiches the sensor from the left and right, so that the mud prevention effect is improved. Note that the interlocking pin 51a disposed on the upper part of the 2P bracket to act on the sensor actuator 57a may be removed.

  As shown in FIGS. 10 and 11, a part of the application surface of the resin part 67 to which the label 66 is applied is made into a wrinkle (unevenness) processed surface 68, and the application area is reduced to facilitate peeling. Yes. Generally, in order to make it difficult to peel off the label, the surface to be attached to the part is finished to a smooth surface. In this example, since a part of the affixing surface has been subjected to crease processing, the label can be easily peeled off and separation from the resin component is facilitated.

  The embodiment shown in FIGS. 12 and 13 relates to the mounting position of the stroke detection sensor of the horizontal cylinder. Conventionally, since a sensor for detecting the stroke of the horizontal cylinder is attached to the side surface of the cylinder case, there is a problem that mud or the like enters the cable or sensor. In this example, by installing a horizontal cylinder stroke detection sensor 71 at the upper part of the cylinder case 70, it is possible to prevent mud from entering the sensor 71 and the cable 72. This also makes it easy to adjust and maintain the sensor by simply removing the panel sheet 73.

  The embodiment shown in FIGS. 14 and 15 relates to the weight structure improvement. As shown in FIG. 15, the weights 80A and 80B made up of the mold A and the mold B are alternately stacked to sequentially add weights. It is configured to continue. That is, the mold A is configured to be fastened by being inserted into the mounting holes 82, 82,... Provided in the respective weights by the inner bolts 81a and 81a and the mold B by the outer bolts 81b and 81b. In addition, each weight is provided with a step 83, and the load applied to the bolt can be reduced by placing the next weight on this step.

  According to the configuration as described above, a number of weights having the same shape can be added in piles.

Side view of tractor Power transmission path diagram Side sectional view of essential parts of transmission Rear view showing arrangement of tractor hydraulic valve Side view showing arrangement of tractor hydraulic valve Side view when using 2P link Rear view of the main part Side view when 3P link option is installed Same as above Side view showing the state of label attachment to parts S-S sectional view of FIG. Plan view of horizontal cylinder stroke sensor mounting device Side view of the main part Individual perspective view of weights SS sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main transmission gear mechanism 2 axis | shaft 3 axis | shaft 4 1st speed transmission gear 5 2nd speed transmission gear 6 4th speed transmission gear 7 Constant meshing gear transmission part 8 Clutch claw 9 Main transmission clutch claw

Claims (1)

  In the main transmission gear mechanism (1) capable of shifting in several stages of 1st to 3rd speed or 1st to 4th speed, meshing transmission is possible between the transmission shaft (2) and the counter shaft (3) which are parallel to each other. A plurality of speed change gears (4b, 4c), (5b, 5c), (6b, 6c), provided on the way from the transmission shaft (2) to the counter shaft (3). Is provided with a constant meshing gear transmission (7) that transmits the variable speed rotation to the auxiliary transmission countershaft (11), and a clutch pawl (8) is extended to the constant meshing gear transmission (7) to provide a main transmission clutch pawl ( 9) A tractor transmission which is structured such that one of the several speeds is obtained by meshing with 9).

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