JP5723556B2 - Traveling transmission device for riding type work machine - Google Patents

Description

  The present invention relates to a traveling transmission device of a riding type work machine such as a riding type rice transplanter.

  An example of a riding type farm working machine is a riding type rice transplanter. This riding type rice transplanter has a traveling machine body on which an engine is mounted and a seedling planting device disposed behind the traveling machine body, and the seedling planting device is connected to the traveling machine body so as to be movable up and down. The traveling machine body has left and right front wheels and rear wheels, and the power of the engine is transmitted to the front wheels and the rear wheels via the traveling transmission.

  The traveling transmission device has a hollow traveling mission case, and a shaft group, a gear group, a traveling clutch, a differential device (differential device), a brake, and the like are disposed therein. The traveling mission case is configured to be hollow by fastening a plurality of shell-shaped members with bolts, and a two-part system (two-part system) is disclosed in Patent Document 1. In the two-split method, one end of the shaft is supported by one part, and the other end of the shaft is supported by the other part.

  In recent years, riding rice transplanters often have an HST (hydrostatic continuously variable transmission) in order to enhance the running feeling, and the HST is attached to a running mission case. Further, since there is a region where transmission efficiency is lowered only with HST, it is widely practiced to install HMT (hydraulic mechanical continuously variable transmission) using both HST and a planetary gear mechanism. HMT has been installed on type rice transplanters from early on and has been highly evaluated in the market.

  Furthermore, although the riding type rice transplanter is a wheel traveling type and is steered by turning the front wheel, a front axle device is attached to the traveling mission case, and a differential device is provided inside the traveling mission case. The rotational speed of the left and right front wheels is changed.

JP 2005-160406 A

  Now, since the inside of the traveling transmission case of the traveling transmission is hermetically sealed, it is inevitable that the traveling transmission case is composed of a plurality of members. However, in the configuration in which the shaft is simply divided into two parts as in the prior art, since the shaft is simply supported at both ends with one end supported by one part and the other end supported by the other part, assembly is troublesome.

  In other words, the holes that fit the shafts are provided in the two parts that make up the traveling mission case, and the other parts cannot be fitted into the respective shafts unless the posture of each shaft is accurately held in the one part. In the split method, each shaft has only one end fitted into the hole of one part before assembling. The work of fitting the other part into the shaft becomes troublesome.

  In particular, after the traveling mission case is incorporated into a work machine such as a rice transplanter, the shaft is often turned sideways, so that if the other part is removed for maintenance or parts replacement, the shaft tends to collapse due to its own weight. It was more troublesome to fit the other part.

  Furthermore, in the simple split method, the shaft is only supported at one end and the other end, so the support span is inevitably long, and the strength against bending is reduced and the durability is lowered. There is a risk of doing.

  This invention makes it a subject to improve such a present condition.

As means for solving the above problems, the inventors have completed the invention of each claim. Among these, the invention of claim 1 has a traveling mission case and a shaft group and a gear group disposed therein, and the traveling mission case includes a main body portion having a deep depth and a shallow lid portion covering the main body portion. The shaft group is arranged in a posture intersecting with the opening surfaces of the main body portion and the lid portion, and at least a part of the shaft group is disposed on the main body portion of the traveling mission case. An intermediate member functioning as a bearing for the vehicle is detachably fixed, and a wheel drive axle device is attached to each of the main body portion and the lid portion of the traveling mission case, and in the traveling mission case, while power transmission on one of the axle device and the wheel drive shaft and the other wheel driving shaft for power transmission to the other of the axle device is arranged concentrically, the traveling transmission case Is arranged differential device for differentially both wheels drive shaft between the body portion and the intermediate member.

  The invention of claim 2 embodies claim 1 and further comprises an HST to which power from the engine is transmitted and a planetary gear mechanism that constitutes an HMT in combination with the HST. The HST is attached to the outer surface of the bottom portion located on the opposite side of the lid portion of the main body portion in the traveling mission case, and the planetary gear mechanism is connected to the bottom portion of the main body portion in the traveling mission case. And the intermediate member.

The invention of claim 3 further embodies claim 1 or 2, and provides a space in which oil can freely flow between the inner periphery of the main body and the outer periphery of the intermediate member in the traveling mission case. Yes.

  According to the first aspect of the present invention, since the shaft disposed inside the traveling mission case is supported by the main body and the intermediate member even when the lid is removed, the shaft is accurately positioned at the correct position. Kept in a state. For this reason, even when the other end of the shaft fits into the lid, the lid can be easily fitted, and thus the traveling mission case can be assembled accurately and efficiently. In addition, since the intermediate member can function as a reinforcing member, it contributes to increasing the strength of the traveling mission case.

  Also, when the lid is removed for maintenance or parts replacement with the traveling mission case installed in the work implement, the shaft is stably held in place even if the shaft is in a horizontal orientation. Therefore, the lid can be easily reattached. Therefore, it can be said that the present invention is particularly effective for improving workability in maintenance and parts replacement.

  Furthermore, if the shaft / gear is removed for maintenance or repair, the traveling mission case often has to be removed from the fuselage when it is a simple divide-by-two method. However, in the present invention, since the depth of the main body part and the intermediate member are included, many of the shafts and gears can be held in the predetermined depth in the main body part. It is possible to perform operations such as shaft replacement by removing only the lid while the part is attached to the airframe. For this reason, the frequency with which the traveling mission case is removed during maintenance and repair can be significantly reduced. In this respect, maintenance and repair workability can be improved.

  Moreover, since the support span of the shaft can be shortened by arranging the intermediate member, the strength of the shaft can be increased and the durability can be improved. Further, the shaft can be supported only by the main body portion and the intermediate member, or can be supported only by the intermediate member and the lid portion. Therefore, the freedom of the shaft support structure can be improved. This is also a feature of the present invention.

  Now, it is theoretically possible to provide a plurality of bearings on one part that constitutes the traveling mission case. In this case, however, the part must be manufactured as a casting using a mold and then subjected to complicated post-processing. This requires low productivity and high costs. That is, one mold is manufactured for each traveling mission case, and the procedures such as pouring, curing, removing the mold, and cutting of the bearing portion must be taken, resulting in low productivity and high cost. Moreover, since the shaft cannot be set with the gear attached to the shaft, the assembly is also very troublesome.

  On the other hand, if a separable intermediate member is provided as in the present invention, it is sufficient to provide a bearing portion for supporting one end of the shaft in the main body portion constituting the traveling mission case. Therefore, die cast products (molded products) manufactured by methods such as pouring into a cavity, solidification, and die removal after separating the molds using molds that can be adhered and separated freely are possible. Can be adopted.

  Thus, the shaft can be stably supported by using the intermediate member while manufacturing the main body (or the lid) with high dimensional accuracy and efficiency at low cost. Therefore, it is possible to increase productivity and contribute to cost reduction. In addition, since the intermediate member can be attached and detached, the shaft can be assembled by a simple procedure in which one end is inserted into the main body while the member such as a gear is attached, and then the intermediate member is set. For this reason, assembly work is also easy.

  As described above, combining the HST and the planetary gear mechanism to configure the HMT can ensure high transmission efficiency over a wide range from low speed to high speed, but if the traveling mission case is a simple split system, There is a concern that the support span of the gear mechanism becomes long and the durability is lowered.

  On the other hand, if the structure of Claim 2 is employ | adopted, since the planetary gear mechanism can be supported also by an intermediate member, the support stability of a planetary gear mechanism can be improved significantly. In addition, it is easy to dispose the travel clutch between the main body and the intermediate member, which can contribute to the compactness of the travel transmission. Furthermore, since the planetary gear mechanism is held between the main body and the intermediate member, the lid can be attached or detached while the HMT is attached to the traveling mission case. Easy assembly and maintenance.

As described above, the differential device is indispensable in the wheel traveling type working machine, but if the two wheel drive shafts are not stably supported, the durability is lowered. In this regard, when the configuration of claim 1 of the present application is adopted, the differential device is stably held by the main body portion and the intermediate member, and as a result, the two wheel drive shafts are also stably supported. As a result, the durability of the differential mechanism can be improved.

  It is normal for oil to collect inside the traveling mission case. In particular, in a working machine having an HST, it is common that the traveling mission case is also used as a tank for hydraulic oil of the HST, and when the working machine includes a hydraulic cylinder and a power steering, The traveling mission case is also used as a tank for these hydraulic oils.

And since the hydraulic oil often becomes hot, it is necessary to circulate it inside the traveling mission case and cool it as much as possible. However, if the structure of claim 3 is adopted, the oil (hydraulic oil) inside the traveling mission case is used. Since the circulation of the oil is not hindered, the oil cooling function is not hindered. Further, since the intermediate member can be reduced in size, the material cost can be suppressed and the travel transmission can be reduced in weight.

It is a side view of the rice transplanter concerning an embodiment. It is a top view of the whole rice transplanter. It is a side view which shows the outline of a traveling body. It is a bottom view which shows the outline of a traveling body. (A) is a perspective view of a traveling mission case, (B) is a rear view of the principal part which separated the intermediate member while showing a traveling mission case with a virtual line. It is a transmission system diagram. It is a separate perspective view of the principal part. (A) is the perspective view which looked at the inside of a traveling mission case from back, (B) is the isolation | separation perspective view inside a traveling mission case. It is a side view in the state where a lid part of a run mission case was omitted. It is a plane sectional view showing a travel transmission. It is a partial plane sectional view showing a travel transmission.

  Next, an embodiment in which the present invention is applied to a riding type rice transplanter (hereinafter simply referred to as “rice transplanter”) will be described with reference to the drawings. In the following description, the words “front and rear” and “left and right” are used to specify the direction, which is based on the posture of the operator facing the forward direction.

(1). Outline of rice transplanter First, the outline of the rice transplanter will be described with reference to FIGS. As shown in FIGS. 1 and 2, the rice transplanter has a traveling machine body 1 that is supported by the left and right front wheels 2 and the left and right rear wheels 3, and a seedling planting device 4 that is disposed behind the traveling machine body 1. . The front wheel 2 is attached to the traveling machine body 1 so as to be able to turn horizontally, and the rear wheel 3 is attached to the traveling machine body 1 so as to be unable to turn horizontally.

  The seedling planting device 4 is connected to the traveling machine body 1 through a lifting link mechanism 6 so as to be movable up and down. The seedling planting device 4 is lifted and lowered by rotating the lifting link mechanism 6 with a hydraulic lifting cylinder 5. The seedling planting device 4 has a rotary planting mechanism, a seedling platform, a float, and the like, but details thereof are omitted because they are not directly related to the present invention. Although not shown, a fertilizer application device can be attached to the rear part of the traveling machine body 1.

  As shown in FIGS. 3 and 4, the traveling machine body 1 has a machine body frame 7 made up of a number of members, and supports the engine 8 at the front part of the machine body frame 7. A traveling mission case 9 constituting a traveling transmission device is disposed behind the engine 8, and the front wheels 2 are attached to the left and right front axle devices 10 attached to the front portion of the traveling mission case 9. The rear wheel 3 is attached to a rear axle case 12, and the traveling mission case 9 and the rear axle case 12 are connected by a cylindrical connecting frame 11.

  The engine 8 is covered with a bonnet 15, and spare seedling stands 16 are arranged on the left and right sides of the bonnet 15. A driver's seat 17 is arranged behind the bonnet 15. The traveling machine body 1 has a vehicle body cover (step) 18 on which an operator is placed. Although a fuel tank is arranged below the seat 17, details are omitted. A steering handle 19 is disposed in front of the driver seat 17.

  As shown in FIGS. 4 and 5, the front axle device 10 includes a fixed support portion 10a fixed to the front body frame via a bracket 7a, and a rotation support portion attached to the fixed support portion 10a so as to be substantially horizontally rotatable. 10b, and the front wheel 2 is attached to the front axle provided in the rotation support portion 10b. A knuckle arm 20 is fixed to the rotation support portion 10b, and a tie rod 21 is connected to the knuckle arm 20 so as to be relatively rotatable. When the steering handle 19 is rotated, the left and right tie rods 21 move simultaneously, thereby causing the left and right front wheels 2 to turn horizontally in the same direction. As a result, the rice transplanter is steered.

  For example, as shown in FIG. 5, the HST 24 is attached to the left side surface of the traveling mission case 9. Power is transmitted from the engine 8 to the HST 24 by the belt 25. The engine 8 is placed horizontally so that the output shaft (crankshaft) has a horizontally long posture. Therefore, the HST 24 is also attached to the left side surface of the traveling mission case 9 with the input shaft and the output shaft being horizontally long. ing. A cooling fan 27 is fixed to the input shaft 26 of the HST 24.

  The HST 24 incorporates a swash plate for controlling the rate at which the power of the hydraulic pump is transmitted to the hydraulic motor, and this swash plate is driven by rotating an upward control shaft 28 shown in FIG. 5, for example. Is done. On the other hand, as shown in FIG. 4, a shift pedal 29 is provided in a portion of the control floor on the right side of the traveling mission case 9 in plan view. The rotation angle (depression amount) of the shift pedal 29 is detected by a potentiometer.

  Then, a control motor (not shown) is driven based on the detection signal of the potentiometer, and the control shaft 28 is rotated by a link mechanism (not shown) moved by the control motor, so that the hydraulic pump in the HST 24 is changed to the hydraulic motor. As a result, the vehicle speed is steplessly adjusted according to the amount of depression of the shift pedal 29.

  For example, as shown in FIG. 5, a hydraulic power steering unit 30 is attached to the front end of the traveling mission case 9, and the rotational torque of the steering handle 19 is amplified by the power steering unit 30 and transmitted to the tie rod 21. .

  For example, as shown in FIG. 5A, an oil pump unit 31 driven by a first drive shaft 41 directly connected to the input shaft 26 of the HST 24 is disposed on the right side surface of the traveling mission case 9. The oil pump unit 31 is a tandem type in which a charge pump 31a and an auxiliary pump 31b are arranged in parallel, and both the pumps 31a and 31b are driven by the input shaft 26 of the HST 24.

  Oil is sucked into the charge pump 31a and the auxiliary pump 31b through the oil filter 31 '. The input shaft 26 of the HST 24 is always rotating as long as the engine is operated. Therefore, the charge pump 31a is always rotating. The pressure oil generated by the charge pump 31a is sent to the hydraulic oil supply port of the HST 24 through the pipe 32. The pressure oil generated by the auxiliary pump 31b is sent to the power steering unit 30 (the pipe to be sent to the power steering unit 30 is omitted in the figure). Excess oil or leak oil discharged from the HST 24 returns to the traveling mission case 9 through the drain pipe 35.

  A valve unit 34 for controlling the lift cylinder 5 described above is fixed to the rear portion of the traveling mission case 9, and the pressure oil discharged from the power steering unit 30 is sent to the valve unit 34 through a pipe 33. A steering support portion 36 protruding forward is formed on the front surface of the traveling mission case 9, and the power steering unit 30 is attached to the steering support portion 36. The front end of the traveling mission case 9 and the engine 8 are connected by a bracket.

(2). Transmission system Next, details of the travel transmission will be described with reference to FIG. For example, as shown in FIG. 5B, the traveling mission case 9 is composed of two shell-like members, which are a main portion 9a having a deep depth and a lid portion 9b covering the main portion 9a and having a shallower depth than the main portion 9a. Both are fastened with bolts. Both opening surfaces (fastening surfaces and mating surfaces) are orthogonal to (transverse) the axis of each axis described later.

  Next, the transmission system will be described mainly with reference to FIG. The HST 24 includes a hydraulic pump 38 driven by the input shaft 26 and a hydraulic motor 39 driven by the hydraulic pump 38. The hydraulic motor 39 has an output shaft 40. A first drive shaft 41 that rotates concentrically and integrally with the input shaft 26 of the HST 24 is connected to the input shaft 26. The main drive gear 42 fixed to the first drive shaft 41 and the output shaft 40 are arranged so as to be freely rotatable. The driven carrier gear 43 is always meshed.

  On the other hand, the internal gear 45 is arranged in an idle manner at the end of the second drive shaft 44 arranged concentrically with the output shaft 40, while a sun gear 46 is fixed to the output shaft 41 of the HST 24. The planetary gear 47 attached to the driven carrier gear 43 meshes with the sun gear 46. Such a planetary gear mechanism and the HST 24 constitute an HMT. The second drive shaft 44 and the internal gear 45 are connected to each other via a ball-type traveling clutch 48 so as to be freely disengaged.

  Next, a mechanical auxiliary transmission mechanism will be described. First to fourth gears 49 to 52 are fixed to the second drive shaft 44 so as not to be relatively rotatable. In addition, a first intermediate rotation shaft 53 and a second intermediate rotation shaft 54 that are parallel to the first rotation shaft 44 are disposed inside the traveling mission case 9, and the outer diameter of the second intermediate rotation shaft 53 is different. The fifth gear 55 and the sixth gear 56 are attached so as not to be relatively rotatable and slidable in the axial direction, and the seventh gear 57 and the eighth gear 58 are disposed on both the left and right sides of the fifth gear 55 and the sixth gear 56. And are fixed so that relative rotation is impossible. A twelfth gear 68 is engraved at one end of the first intermediate rotating shaft 53, and a multi-plate brake (parking brake) 59 is provided at the other end.

  The second intermediate rotation shaft 54 is a reverse rotation idle shaft, and the ninth gear 60 that is always meshed with the first gear 49 and the tenth gear that the sixth gear 56 slides and disengages are fixed in a relatively non-rotatable manner. Has been. Since FIG. 6 is shown in an unfolded state, the second drive shaft 44 and the second intermediate shaft 52 are drawn apart from each other. However, actually, as shown by the arrows, the fifth gear is shown. 55 meshes with the second gear 50, and the sixth gear 56 can selectively mesh with either the third gear 60 or the tenth gear 61.

  In the traveling mission case 9, a left wheel drive shaft 63 and a right wheel drive shaft 64 are arranged in parallel with the other shafts. The left and right wheel drive shafts 63 and 64 are differentially connected by a differential device 66 having a differential case 65, and an eleventh gear 67 and a twelfth gear 68 fixed to the differential case 65 are engaged with each other. That is, power is transmitted from the second intermediate shaft 53 to the left and right wheel drive shafts 63 and 64. The differential device 66 can be deactivated by the differential lock device 69. The traveling mission case 9 and the left and right front axle devices 10 are connected by an axle housing 70.

  Although details are omitted, by sliding the fifth gear 55 and the sixth gear 56, the rice transplanter can be planted in a planting mode (low speed forward), a road traveling mode (high speed forward), a seedling mode (neutral), a neutral mode, There are 5 modes for reverse mode. The sliding operation of the fifth gear 55 and the sixth gear 56 is performed by operating the speed change lever 71 shown in FIG.

  Although it is not directly related to the present invention, the details are omitted. However, when the speed change pedal 29 (see FIGS. 2 and 3) is depressed, the traveling clutch 48 is automatically engaged, and when the speed change pedal 29 is fully returned, the brake is applied. 59 works lightly. Further, the brake 59 can be strongly applied by depressing the brake pedal 72 (see FIG. 3).

Further, a third intermediate rotating shaft 74 is disposed inside the traveling mission case 9. A thirteenth gear 75 is fixed on the third intermediate rotation shaft 74 so as not to be relatively rotatable, and a fourteenth gear 76 is disposed so as to be freely rotatable. The eighth gear 58 on the second intermediate rotation shaft 53 is arranged. To the fourteenth gear 76. The thirteenth gear 75 meshes with the fourteenth gear 52 on the second drive shaft 44 via the seventh gear 57 on the first intermediate rotation shaft 53, whereby the HMT output before passing through the auxiliary transmission mechanism. The rotation is transmitted to the 13th gear 75.
They are meeting each other.

  A work output shaft 78 projects rearward from the right side portion of the traveling mission case 9, and power is transmitted to the work output shaft 78 from the third intermediate rotating shaft 74 by a pair of bevel gears 79. The power of the work output shaft 78 is input to the inter-case case 80, from which power is transmitted to the seedling planting device 4 by the PTO shaft 81.

  A rear wheel drive shaft 82 protrudes rearward from the rear surface of the left side portion of the traveling mission case 9 slightly from the center in the left width direction. The rear wheel drive shaft 82 is transmitted with power from the fourth intermediate rotation shaft 83 via a pair of bevel gears 84. Further, a fifteenth gear 85 that meshes with the thirteenth gear 76 is fixed to the fourth intermediate rotation shaft 83, and the rear wheel drive shaft 82 is rotated by a drive shaft 86 that extends in the front-rear direction of the fuselage. It is transmitted to the inside of the axle case 12.

(3) Details of the shaft support structure As described above, the traveling mission case 9 is composed of the main body portion 9a having a deep depth and the lid portion 9b having a shallow depth, and is conceptually shown in FIG. As shown, an intermediate member 87 extending in the front-rear direction is disposed inside the main body 9a, and is detachably (removably) fixed to a substantially intermediate position in the left-right width direction of the main body 9a. . The five shafts of the second drive shaft 44, the first to fourth intermediate rotation shafts 53, 54, 74, and 83 and one end portion of the differential case 65 are rotatably supported by an intermediate member 87 through bearings. .

  Although the first drive shaft 41 is not supported by the intermediate member 87, the first drive shaft 41 can be supported by the intermediate member 87. Specific embodiments of the arrangement of the shaft group, the arrangement of the gear group, and the shaft support structure are shown in FIG. This point will be described next.

  The traveling mission case 9 has a shape close to an egg shape in a side view, and a steering support portion 36 is provided at a lower portion of the front end portion thereof. In the present embodiment, the hydraulic oil used in the HST 24 is returned to the inside of the traveling mission case 9 via the steering support portion 36 (to cool the hydraulic oil).

  As shown in FIG. 9, the group of shafts has a posture in which the respective rotation axes extend in the vehicle width direction (left-right direction), and are arranged in a direction from the front to the rear lower part of the traveling mission case 9 as a whole. Is arranged. Specifically, the first drive shaft 41 is disposed at the uppermost and front portion, the second drive shaft 44 is disposed behind the first drive shaft 41, and the third intermediate rotation shaft 54 and the second drive shaft 44 are disposed below the second drive shaft 44. The second intermediate rotating shaft 53 is arranged in a state separated from the front and rear, and further, the wheel drive shafts 63 and 64 and the third intermediate rotating shaft 74 are arranged below the second intermediate rotating shaft 53 in a state separated from the front and rear. The fourth intermediate rotating shaft 83 is disposed at the lowermost and rearmost position.

  The intermediate member 87 is plate-shaped and extends long along the direction in which the shaft groups are arranged. Therefore, the intermediate member 87 has an appearance extending long in an oblique direction in a side view. In addition, a large space is provided between the outer peripheral surface of the intermediate member 87 and the inner peripheral surface of the main body 9a in the traveling mission case 9, and therefore, the hydraulic oil is a space between the intermediate member 87 of the main body 9a. Can move freely.

  As can be understood from FIG. 5 (B), the intermediate member 87 is disposed in a state of being deeply inserted into the main body portion 9a (about the substantially intermediate position in the axial direction and the lateral width direction). As shown in FIG. 7, a boss portion 89 for fixing the intermediate member 87 is formed in the main body portion 9 a, and the peripheral portion of the intermediate member 87 is fastened to the boss portion 89 with a bolt 90. . The boss portion 89 has a stepped shape projecting inward from the bottom inner surface and wall inner surface of the main body portion 9a and an aspect projecting inward from the side wall inner surface of the main body portion 9a into the case. Is present.

  As shown in FIG. 10, the input shaft 26 of the HST 24 and the first drive shaft 41 are connected via a main drive gear 42. Further, the right end portion of the first drive shaft 41 is rotatably supported by the lid portion 9b via a bearing. Further, the second drive shaft 44 is rotatably supported by the intermediate member 87 at the left and right central portions thereof, and the right end portion by the lid portion 9b via bearings, and is further supported at the left end portion of the second drive shaft 44. The internal gear 45 and the sun gear 46 are juxtaposed with each other, and the sun gear 46 is rotatably supported on the left side wall of the main body 9a via a bearing.

  Accordingly, the second drive shaft 44 is rotatably supported by the main body portion 9a via the sun gear 46, and is also rotatably supported by the intermediate member 87 and the lid portion 9b. A traveling clutch 48 is formed between the second drive shaft 44 and the internal gear 45. These internal gear 45 and the traveling clutch 48 are short between the main body 9a and the intermediate member 87. Since it falls within the span range, the support strength of the second drive shaft 44 is extremely high, and the support stability of the internal gear 45 and the travel clutch 48 is also excellent. In addition, since the planetary gear mechanism such as the internal gear 45 and the traveling clutch 48 are arranged close to each other, the traveling transmission can be made compact.

  Moreover, since the attitude | position of the 2nd drive shaft 44 is firmly hold | maintained by the main-body part 9a and the intermediate member 87, position alignment of the cover part 9b can also be performed correctly. Therefore, it is easy to assemble and maintain. A shifter for connecting and disconnecting the travel clutch 48 is indicated by reference numeral 91 (see 9 in FIGS. 10 and 8B).

  The first intermediate rotation shaft 53 and the second intermediate rotation shaft 54 are rotatably supported by the intermediate member 87 and the lid portion 9b via bearings. Since both the intermediate rotating shafts 53 and 54 can be shortened in length as compared with the case where they are supported by the main body 9a and the lid 9b, the strength against bending can be increased accordingly and the posture stability is also excellent. Therefore, durability can be improved and assembly and maintenance can be facilitated.

  By shortening the first intermediate rotation shaft 53 and the second intermediate rotation shaft 54, a space formed between the main body portion 9a and the intermediate member 87 is reduced between the planetary gear mechanism and the differential device 66 that require a space in the radial direction. Can be used for housing.

  As shown in FIGS. 10 and 11, the brake 59 is attached to the inside of the lid portion 9b. And since the main-body part 9a of the driving | running | working mission case 9 is being fixed to the rear axle case 12 with the connection frame 11, the main-body part 9a cannot be removed easily, but the cover part 9b can be removed comparatively easily. Since the brake 59 is overused, the necessity for maintenance and replacement is high. In this embodiment, since the brake 59 is attached to the lid portion 9b that can be easily removed, the maintenance and replacement of the brake 59 can be easily performed. . Although omitted in the figure, the operation member of the brake 59 is provided in the lid portion 9b.

  More specifically, in the present embodiment, the main body 9a of the traveling mission case 9 functions as a strength member (frame member) of the traveling machine body 1 by being fixed to the rear axle case 12 by the connecting frame 11. Although the advantage of simplifying the overall structure of the traveling transmission 1 can be obtained by using the configuration, the maintenance of the brake 59 can be easily replaced while ensuring the advantage.

  The fifth gear 55 and the sixth gear 56 provided on the second intermediate rotation shaft 53 are slid by, for example, a shift shifter 92 shown in FIG. The shift shifter 92 is attached to a horizontally long shift bar 93, and the shift bar 93 is partially exposed on the left side of the main body 9 a in the traveling mission case 9.

  The shift bar 93 is slidably fitted between the intermediate member 87 and the lid portion 9b. For example, as shown in FIG. 8 (B), the shift bar 93 is formed with a plurality of grooves (five lines) for holding the position, and a pressing element biased by a spring in the grooves 94. (For example, a ball) is fitted, and the shift shifter 92 has five modes: a rice transplanter, a planting mode (low speed forward), a road traveling mode (high speed forward), a seedling mode (neutral), a neutral mode, and a reverse mode. Held in one of them.

  As shown in FIG. 8, the intermediate member 87 is provided with an upward hole 95 into which a holder (not shown) for holding a spring and a pressing element is inserted. Thus, since the shift bar 93 can be temporarily supported together with the subtransmission mechanism on the intermediate member 87 that is separable from the main body 9a, the assembly of the travel transmission is also simplified. This point is one of the advantages of the present embodiment and can be an independent invention (conventionally, since the shift bar is supported by the traveling mission case, the assembly is troublesome).

  As shown in FIG. 10, the differential case 65 is rotatably supported by the main body 9a and the intermediate member 87 via a bearing. The main body portion 9a is provided with an inward protruding portion 9c protruding toward the lid portion 9b, and the left end portion of the differential case 65 is rotatably supported by the end portion of the inward protruding portion 9c. Thus, since the differential case 65 is rotatably supported at both ends, the differential case 65 maintains extremely high stability with a short width. In the present embodiment, a diff lock clutch 96 constituting the diff lock device 69 is disposed inside an inwardly protruding portion 9c provided on the main body 9a. Therefore, the differential lock device 69 can be made compact.

  The inward projecting portion 9c has a cylindrical shape as a whole, but is partially provided with a notch (not shown) along the width direction and supported by the main body portion 9a near the projecting portion 9c. By connecting the fork portion of the differential lock fork (not shown) to the differential lock clutch 96 through this notch, the differential lock clutch 96 can be slidably operated in the axial direction.

  As shown in FIG. 11, the third intermediate rotating shaft 74 is rotatably supported by the intermediate member 87 and the lid portion 9b via a bearing. Since the third intermediate rotating shaft 74 can be shortened in length as compared with the case where it is supported by the main body portion 9a, the strength and stability can be improved. The fourth intermediate rotation shaft 83 is rotatably supported by the main body portion 9a and the intermediate member 87. And since the length of the 4th intermediate | middle rotating shaft 83 is very short, very high intensity | strength and stability are securable.

  Now, in order to attach the third intermediate rotation shaft 74 and the work drive shaft 78 to the lid portion 9b, there is a void 97 having an L-shaped flat cross section and an opening inward of the case and an opening in the rear of the case. Yes. The work drive shaft 78 is rotatably supported in the space 97 by two front and rear bearings 88 and is prevented from being detached by a snap ring 99. The driven bevel gear 79 provided on the work drive shaft 78 is set to a size that can be removed from the rear opening of the space 79.

  More specifically, the driven bevel gear 79 of the third intermediate shaft 74 is engaged with the spline of the third intermediate shaft 74 on the outer side of the bearing and is located in the space 79 so that the rear opening of the space 97 is located. Therefore, only the bevel gear 79 can be removed from the third intermediate shaft 74. For this reason, the snap ring 99 can be removed without removing the lid portion 9b one by one. By removing the work drive shaft 78, the two bevel gears 79 can be exchanged.

  The work drive shaft 78 rotates in proportion to the traveling speed. Therefore, the seedling planting interval (between plants) is basically adjusted by the strain adjustment mechanism built in the strain case 80. As a manufacturer, there is a case where it is desired to optionally prepare specifications that slightly change between stocks relative to reference stocks according to the characteristics of crops and regions. That is, there is a case where a fine adjustment function between stocks may be prepared as an option. In this embodiment, since the work drive shaft 78 can be easily removed and the two bevel gears 79 can be replaced, the demand for fine adjustment between the stocks can be easily met.

  Now, in the rice transplanter, the raising / lowering cylinder 5 changes the posture of the seedling planting device 4 so that the planting depth of the seedling is constant even if there is unevenness in the field. In this case, depending on the vehicle speed Changing the operating sensitivity of the elevating cylinder 5 is performed. For this purpose, a sensor for detecting the vehicle speed is required. The vehicle speed sensor may be used for other purposes, such as providing a vehicle speed sensor to alert the operator when the speed is excessive.

  In Japanese Patent Application Laid-Open No. 2000-175525, the rotational speed of the rear wheel drive shaft is detected by a vehicle speed sensor, but the rear wheel drive shaft is often left exposed, so there is a concern that the vehicle speed sensor may become dirty. Is done. If the rear wheel drive shaft and the vehicle speed sensor are covered with a cover, the structure becomes complicated and the cost increases.

  In contrast, in the present embodiment, as shown in FIG. 11, a vehicle speed sensor 100 is provided outside the work drive shaft 78 in the lid portion 9 b so that the vehicle speed is calculated from the rotational speed of the work drive shaft 78. It is composed. The work drive shaft 78 is provided with a detection gear 101 that rotates with the shaft 78 between the two bearings 88, and detects the vehicle speed by converting the unevenness of the gear into the number of pulses.

  In this embodiment, since the vehicle speed sensor 100 is protected by the lid portion 9b, there is no fear of contamination even if a separate cover is not provided. Further, since the side surface of the lid portion 9b is exposed to the outside (right side), the vehicle speed sensor 100 can be easily attached and detached.

  The lid 9a can be removed after draining the oil inside the traveling mission case 9, but in this case, the right front wheel is also removed. Accordingly, when the lid portion 9a is removed, the traveling machine body 1 is in a three-wheel supported state, but the traveling machine body 1 can be stably held by supporting it with some member. Therefore, even if the whole is not lifted and disassembled by a crane or the like at a maintenance shop, the maintenance and repair of the inside of the traveling mission case 9 can be performed by removing the lid portion 9b even in the user's warehouse or work site, for example. . For this reason, the labor required for maintenance and repair can be remarkably reduced.

(4). Others The present invention can be embodied in various ways other than the above embodiment. For example, the specific shapes of the traveling mission case and the intermediate member can be arbitrarily changed as necessary. It is also possible to configure a plurality of intermediate members. In this case, a plurality of intermediate members can be arranged separately in the spreading direction of the opening surface of the main body, or can be arranged separately in the depth direction of the main body (thus, the shaft Can be supported by a plurality of intermediate members.)

  When providing a continuously variable transmission, it is not limited to HST, and a belt-type CVT or the like can also be provided. Moreover, when applying to seedling transplanting machines, such as a rice transplanter, it is also possible to incorporate an inter-strain adjustment device in a traveling mission case. Moreover, this invention is applicable also to other working machines other than a rice transplanter.

  The invention of the present application is embodied in a riding-type farm work machine such as a rice transplanter and exhibits utility. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 4 Seedling device 8 Engine 9 Traveling mission case 9a Main body part 9b Cover part 24 HST as an example of continuously variable transmission
DESCRIPTION OF SYMBOLS 10 Front axle apparatus 11 Connection frame 12 Rear axle case 26 HST input shaft 40 HST output shaft 41 First drive shaft 44 Second drive shaft 45 Internal gear 48 constituting planetary gear mechanism (HMT) 48 Traveling clutch 53, 54 , 74, 83 Intermediate rotating shaft 59 Brake (parking brake)
63, 64 Wheel drive shaft 65 Differential case 66 Differential device 72 Brake pedal 87 Intermediate member

Claims (3)

It has a traveling mission case and a group of shafts and gears arranged inside it,
The traveling mission case has a main body portion having a deep depth and a shallow lid portion covering the main body portion, and the shaft group is disposed in a posture intersecting with the opening surfaces of the main body portion and the lid portion.
The structure
An intermediate member that functions as a bearing for at least a part of the shaft group is detachably fixed to the main body of the traveling mission case,
A wheel drive axle device is attached to each of the main body portion and the lid portion of the traveling mission case, and in the traveling mission case, one wheel drive shaft for transmitting power to one axle device and the other wheel drive shaft. The other wheel drive shaft that transmits power to the axle device is arranged concentrically ,
In the traveling mission case, a differential device for differentially driving both wheel drive shafts is disposed between the main body portion and the intermediate member,
A traveling transmission for a riding-type work machine. Furthermore, it has an HST to which power from the engine is transmitted, and a planetary gear mechanism that constitutes an HMT in combination with the HST,
The HST is attached to an outer surface of a bottom portion located on the opposite side of the lid portion of the main body portion in the traveling mission case, and the planetary gear mechanism is connected to the bottom portion of the main body portion and the intermediate member in the traveling mission case. Arranged between
The traveling transmission device for a riding type work machine according to claim 1. A space in which oil can freely circulate between the inner periphery of the main body portion and the outer periphery of the intermediate member in the traveling mission case,
The traveling transmission device for a riding type work machine according to claim 1 or 2.

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