JPH07164903A - Transmission structure for traveling of four-wheel drive type work vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] Selective switching between the standard transmission state in which the steered wheels are driven at approximately the same speed as the non-steered wheels, and the increased transmission state in which the steered wheels are driven faster than the non-steered wheels. In a traveling power transmission structure for a four-wheel drive type work vehicle equipped with a free steering wheel transmission, when a working device is connected to the non-steering wheel side, a balance weight attached to the steering wheel side opposite to this side Is configured to be lightweight. [Structure] The steered wheel transmission device 18 is configured by a mechanical speed change mechanism by gear shifting, and non-steered wheels 2a, 2 in a steered wheel support member 5 supporting the steered wheels 1a, 1b.
The steering wheel transmission 18 is arranged at a position on the b side.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a traveling transmission disposed at the rear portion of an airframe, and has an average peripheral speed of a pair of left and right steerable front wheels and a pair of left and right rear wheels. Of the front wheels that can be switched between a standard transmission state in which the average peripheral speed of the pair of front wheels is the same or substantially the same, and an increased transmission state in which the average peripheral speed of the pair of front wheels is greater than the average peripheral speed of the pair of rear wheels. The present invention relates to a traveling transmission structure of an agricultural tractor provided with a transmission. 2. Description of the Related Art In the above-mentioned agricultural tractor, the front wheels pull and swing the machine body by operating the front wheels and switching the front wheel transmission to the speed-increasing transmission state to drive the front wheels to speed up. Therefore, it is considered that the vehicle can turn in a smaller radius than when the front wheel peripheral speed is made equal to the rear wheel peripheral speed.
In this type of agricultural tractor, conventionally, for example, JP-A-5353
As shown in Japanese Patent No. 119530, a front wheel transmission was attached to a traveling transmission located at the rear of the machine body. In an agricultural tractor, various working devices such as a rotary tiller are often connected to the rear part of the body, and the weight of the working device hanging on the rear part of the body when connecting the working devices. A balance weight is attached to the front part of the machine to prevent or suppress the decrease in the load applied to the front wheels compared to when the work device is not connected and the reduction of the small turning action when the front wheels are accelerated. Sometimes. As described above, when the balance weight is attached, the weight of the front-wheel transmission is heavier on the rear wheel side than on the front wheel side in the conventional case, so that the weight of the attached weight must be increased. It is an object of the present invention to make it possible to fully exert the small turning action of the speed-increasing front wheels even when a balance weight is required to be mounted, while making the mounting weight as light as possible. A feature of the present invention is that the front wheel transmission is attached to a front wheel support member in the traveling transmission structure for an agricultural tractor described above. And the effects are as follows. By attaching the front wheel transmission device to the front wheel support member, the front wheel transmission device is provided while the weight of the front wheel transmission device is applied to the front wheel side more than before because of the location of the front wheel support member. To be According to the present invention, in order to secure sufficient front wheel ground pressure so that the front wheels in the speed-up state can sufficiently exert the turning effect of the machine body, it is necessary to attach the front balance weight. However, since the weight of the front wheel transmission is heavier on the front wheel side than before, it is possible to use a balance weight that is lighter than before, and the balance weight required when connecting and disconnecting the work equipment I was able to easily put on and take off. EXAMPLE As shown in FIG. 4, a pair of left and right front wheels 1a,
1b is steerable and drivable, and a pair of left and right unsteered rear wheels 2a, 2b are drivable at the rear portion of the traveling machine body. An agricultural tractor is configured by additionally attaching a lift arm 3 that is operably connected and a power take-out shaft 4 that is transmitted to a connecting work device. The pair of front wheels 1a, 1b are attached to the machine body frame 6 via front wheel transmission cases 5 as front wheel supporting members having the front wheels 1a, 1b separately attached at both ends. The front wheel transmission case 5 is connected to the machine body frame 6 so as to swing around the machine body front-rear direction axial center P1 arranged at the left-right intermediate portion, and the front wheel transmission case 5 has a pair of front wheels regardless of the unevenness of the traveling ground. 1a and 1b are configured to move up and down against the machine body due to the rocking of the front wheel transmission case 5 with respect to the machine body, and maintain the machine body in a horizontal or near-posture position when viewed in the front-rear direction. The front wheel transmission case 5 is, as shown in FIG. 1, a body side case portion 5a and a pair of ends connected to the body side case portion 5a so as to swing around a body vertical axis P2. The wheel-side case portions 5b, 5b of the front wheel 1a, 1b are oscillated around the axis P2 by the knuckle arm 7 to steer the front wheels 1a, 1b. Configured. In order to enable driving of the front wheels 1a, 1b and the rear wheels 2a, 2b, a transmission case 9 having a rear portion of the body is equipped with a traveling transmission 9 and an output of an engine 10 is output by a clutch 11 and a clutch 11. Rotating shaft 1
2 is transmitted to the traveling transmission 9 through the transmission transmission 2, and the rotational output of the traveling transmission 9 is transmitted to the rear wheel differential mechanism 13 inside the transmission case 8. A front wheel output shaft 14 provided in the transmission 9 for transmission in a state of projecting forward from the transmission case 8 is interlockingly connected to a rearward projecting input shaft 16 of the front wheel transmission case 5 via a rotary shaft 15. 1, the rotational force of the input shaft 16 is transmitted to a front wheel differential mechanism 19 via a reduction bevel gear 16 and a front wheel transmission 18 mounted inside the front wheel transmission case 5 as shown in FIG. I am doing it. The front wheel transmission 18 is constructed as shown in FIG. That is, the standard transmission gear 21 is integrally rotatably attached to the input cylinder shaft 20 that is interlocked with the reduction bevel gear 17, and the standard transmission gear 21 is increased via the first gear 22, the gear support shaft 23, and the second gear 24. The output cylinder shaft 26 in which the speed-up interlocking gear 25 which is interlocked with the speed is continuously provided to the differential gear case 19a of the front wheel differential mechanism 19.
Between the transmission member 27 and the standard transmission gear 21 which are attached to the output cylinder shaft 26 so as to rotate integrally with the output cylinder shaft 26 through the cylinder body 27a and slide. 28, and the output cylinder shaft 2
6 and the speed increasing interlocking gear 25 between the multi-plate friction clutch 2
9 is provided. Then, the clutches 28 and 29 are turned on and off as the transmission member 27 is slidably operated by a push rod type operation unit 31 as shown in FIG. 3 which is interlocked via a swing shifter 30. In addition, the transmission member 27 and the operating portion 31 are urged by the spring 32 so that the bite clutch 28 is engaged and the friction clutch 29 is disengaged. More specifically, the first operation position S in which the operation portion 31 has a longer protruding length from the body case portion 5a.
When the friction clutch 29 is disengaged and the bite clutch 28 is engaged, the rotational force of the standard transmission gear 21 is transmitted to the output cylinder shaft 26 via the transmission member 27, and the left and right front wheels 1a, 1b are averaged. It becomes a standard transmission state in which the peripheral speed is transmitted to the front wheel differential mechanism 13 so that the peripheral speed and the average peripheral speed of the left and right rear wheels 2a and 2b are the same or substantially the same, and the operating portion 31 is moved from the body side case portion 5a. When it is operated to the second operation position H where the protruding length of the gear is shortened, the bite clutch 28 is disengaged and the friction clutch 29 is engaged so that the speed increasing interlock gear 2
The turning force of 5 is transmitted to the output cylinder shaft 26, and the left and right front wheels 1a,
A speed increasing transmission state is adopted in which the average peripheral speed of 1b is higher than the average peripheral speed of the left and right rear wheels 2a and 2b, and the average peripheral speed of 1b is transmitted to the front wheel differential mechanism 19. Then, it is adapted to be restored and urged to the standard transmission state. As shown in FIG. 2, the rotary cam 33 for operating the operating portion 31 is provided on one of the wheel side case portions 5
Prepared for b. The rotary cam 33 rotates around the axis P2 integrally with the wheel-side case portion 5b with respect to the body-side case portion 5a, and the steering angles from the straight-ahead position to the leftward side and the rightward side are changed. When the front wheels 1a and 1b are in the steering state below the set value, the first circumferential cam portion 33a opposes the operating portion 31 and maintains and operates the operating portion 31 at the first operating position S. When the front wheels 1a and 1b are steered in a steering state in which the steering angles to the left side and the right side are equal to or more than the set value, the second peripheral cam portion 33b or the third peripheral cam is operated. The portion 33c is configured to push the operating portion 31 to the second operating position H. That is, when the front wheels 1a and 1b are in the steering state less than the set angle, the front wheel transmission 18 is in the standard transmission state, and the front wheels 1a and 1b are steered over the set angle or more to operate the front wheel transmission 18. The operation can be switched to the speed-up transmission state. [Other Embodiments] FIG. 5 shows another embodiment of the front wheel transmission device 18, in which the rotational power from the traveling transmission 9 is input at the same rotational speed or is input to the front wheel transmission case 5. It is arranged so as to be transmitted to the shaft 16 and located outside the front wheel transmission case 5, and is attached to the body side case portion 5a of the front wheel transmission case 5. A planetary gear type speed increasing transmission mechanism 36 is provided between the input shaft 34 and the output cylinder shaft 35, and the cylinder portion 37a of the planetary gear support member 37 of the speed increasing transmission mechanism 36 is integrally rotated by spline engagement. When the clutch member 38, which is mounted so as to slide, is engaged with the claw portion 40 provided with the rotating body 39 on the input shaft 34,
The input shaft 34 and the planetary gear support member 37 are interlockingly connected so as to rotate integrally, and a standard transmission state is established in which the rotational force of the input shaft 34 is transmitted to the output cylinder shaft 35 at the same rotational speed, and the clutch member 38 is provided. Is engaged with a stopper 42 fixed to the transmission case 41, the planetary gear support member 37 is fixed so as not to rotate, the rotational force of the input shaft 34 is increased and transmitted to the output cylinder shaft 35. So that it is in a speed increasing transmission state. It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings] FIG. 1 is a sectional view of a partially developed front wheel transmission case. FIG. 2 is a partially cutaway plan view of a front wheel transmission operating portion. FIG. 3 is a rear view of the front wheel transmission operating portion with a partial cutaway. [Figure 4] Side view of the agricultural tractor FIG. 5 is a sectional view of a front wheel transmission according to another embodiment. [Explanation of symbols] 1a, 1b front wheels 2a, 2b rear wheels 5 Forward support member 9 Drive transmission 18 front wheel transmission

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[Procedure Amendment] [Submission Date] December 7, 1994 [Procedure Amendment 1] [Amendment Document Name] Detailed Description [Amendment Item Name] Full Text [Amendment Method] Change [Amendment Content] [Document Name] Details Description [Title of Invention] Transmission structure for traveling of four-wheel drive type working vehicle [Claims] A pair of left and right steering wheels (1a) at one longitudinal end of the vehicle body,
(1b), a pair of left and right unsteered wheels (2a), (2
b), a non-steering wheel (2a), (2b) side of the end of the vehicle body is provided with a connecting portion (3) for detachably connecting the working device, the steering wheel (1a), A standard transmission state in which the average peripheral velocity of (1b) and the average peripheral velocity of the non-steering wheels (2a) and (2b) are the same or substantially the same, and the steering wheel (1
a) and (1b), the average peripheral speed is set to the unsteered wheel (2
a) and (2b) are provided with a steerable wheel transmission (18) which is selectively switchable to a speed increasing transmission state in which the steered wheel transmission (18) is a gear-shifting machine. The steering wheel (1a),
The steering wheel transmission device (18) is arranged at a position on the steering wheel support member (5) supporting (1b) on the side of the non-steering wheels (2a), (2b), and the steering wheel transmission device is arranged. A transmission structure for traveling of a four-wheel drive type working vehicle in which an output shaft (35) of (18) and an input shaft (16) of the steering wheel support member (5) are connected. Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling power transmission structure for a four-wheel drive work vehicle such as an agricultural tractor. A traveling power transmission structure of an agricultural tractor, which is an example of a four-wheel drive type working vehicle, is disclosed in, for example, Japanese Patent Laid-Open No. 53-1.
As disclosed in Japanese Laid-Open Patent Publication No. 19530 and Japanese Utility Model Laid-Open No. 60-102133, a standard transmission state in which the average peripheral speed of steered wheels is substantially the same as the average peripheral speed of non-steered wheels, and non-steered wheels. There is a steering wheel transmission that can be switched to a speed increasing transmission state that is greater than the average peripheral speed of
There is a structure in which the steering wheel transmission can be turned in a small direction by switching the steering wheel transmission to the speed-increasing transmission state when the steering wheel is steered. In this case, the steered wheel transmission is mounted on the mission case supporting the non-steered wheels. In an agricultural tractor, various working devices such as a rotary tiller are often connected to the end of the vehicle body on the non-steering wheel side. When the work devices are connected in this way, the load on the steered wheels is reduced due to the weight of the work devices and the propulsive force of the steered wheels is reduced compared to when the work devices are not connected, thus increasing the speed of the steered wheel transmission. The small turning effect during transmission is reduced. As a result, a balance weight is attached to the steered wheel side in order to prevent a reduction in the small turning action when the steered wheel transmission is in the speed-increasing transmission state. Since the weight of the wheel transmission device is applied to the non-steering wheel side, it is necessary to attach a large weight balance weight to the steering wheel side opposite to this. Therefore, the vehicle equipped with the steered wheel transmission has a larger weight of the vehicle body than the vehicle not equipped with the steered wheel transmission, and tended to have deep marks of steered and unsteered wheels on the ground. It is an object of the present invention to reduce the weight of a balance weight in a traveling power transmission structure for a four-wheel drive type work vehicle by reasonably installing a steering wheel transmission. The feature of the present invention resides in that the traveling power transmission structure for a four-wheel drive type work vehicle as described above is configured as follows. That is, a connecting portion that has a pair of left and right steering wheels at one end in the front-rear direction of the vehicle body and a pair of left and right unsteering wheels at the other end, and detachably connects the working device to the end portion of the vehicle body on the non-steering wheel side. A standard transmission state in which the average peripheral speed of the steered wheels and the average peripheral speed of the non-steered wheels are the same or substantially the same, and the average peripheral speed of the steered wheels is the average peripheral speed of the non-steered wheels. With a steering wheel transmission that can be selectively switched to an increased speed transmission state that is larger than the above, the steering wheel transmission is configured by a mechanical transmission mechanism by gear shifting,
The steered wheel transmission is arranged at a position on the non-steered wheel side of the steered wheel support member that supports the steered wheel, and the output shaft of the steered wheel transmission is connected to the input shaft of the steered wheel support member. There is. By arranging the steered wheel transmission on the non-steered wheel side of the steered wheel support member as in the present invention, a large weight of the steered wheel transmission is applied to the steered wheel side. It will be. Accordingly, when the working device is connected to the end of the vehicle body on the non-steering wheel side opposite to the steered wheel transmission, the steered wheel transmission on the steered wheel side itself serves as a balance weight. There is no need to attach a heavy weight balance weight to the steering wheel side. To the input shaft of the steering wheel support member, relatively high rotation and low torque power before being decelerated by a differential mechanism for the steering wheel, a speed reduction mechanism, etc. in the steering wheel support member is transmitted. Come on. With this, since the power of the above-described relatively high rotation and low torque is transmitted to the steering wheel transmission when configured as in the present invention, the steering wheel transmission can be configured to have a relatively low transmission capacity, The steering wheel transmission can be easily downsized. As described above, even if the balance weight is attached to the steering wheel side, it is not necessary to attach the balance weight having a particularly large weight, so that it is effective in suppressing an increase in the weight of the entire vehicle body. Therefore, it is possible to reduce the labor for attaching and removing the balance weight. This allows
Since it is possible to prevent deep marks of steering and non-steering wheels on the ground, it is possible to improve the running performance of the four-wheel drive work vehicle. Further, since the steered wheel transmission is constructed as a mechanical transmission mechanism by gear shifting, complicated structure such as a case where a hydraulic transmission mechanism is incorporated can be avoided and maintenance is facilitated. Since the steering wheel transmission can be easily downsized by transmitting the power of relatively high rotation and low torque, it is also advantageous in terms of simplification and downsizing of the entire structure. Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a pair of left and right front wheels 1a, 1b
(Corresponding to steering wheel), and a pair of left and right rear wheels 2a, 2b
A lift arm 3 (corresponding to a connecting portion) for connecting various working devices such as a rotary tiller to the rear portion of the vehicle body capable of driving (corresponding to a non-steering wheel) so as to move up and down, and a connected working device. A power take-off shaft 4 for transmitting power to the vehicle is provided to constitute an agricultural tractor that is an example of a four-wheel drive work vehicle. The pair of left and right front wheels 1a, 1b are attached to the body frame 6 via a front wheel transmission case 5 (corresponding to a steering wheel support member) in which the front wheels 1a, 1b are individually supported at both ends. It is installed. The front wheel transmission case 5 is connected to the body frame 6 so as to swing around the front-rear direction axial center P1 of the vehicle body disposed at the left-right intermediate position, and the pair of left and right front wheels 1a and 1b are irrespective of the unevenness of the ground. The rocking of the front wheel transmission case 5 raises and lowers against the vehicle body so that the vehicle body is maintained in a horizontal position or a posture close to this when viewed in the front-rear direction. Next, the front wheels 1a, 1b and the rear wheels 2a, 2
The transmission structure to b will be described. As shown in Figure 1,
A traveling transmission 9 is installed in a transmission case 8 forming the rear part of the vehicle body, and the power of the engine 10 is transmitted to the traveling transmission 9 via a clutch 11 and a rotating shaft 12. Is transmitted to the rear wheel differential mechanism 13 installed in the mission case 8. As shown in FIGS. 1 and 2, a front wheel output shaft 14 provided in the traveling transmission 9 in a state of protruding forward from the transmission case 8 is provided with a rotary shaft 15.
Is connected to the input shaft 34 of the steering wheel transmission 18 which is connected to the front wheel transmission case 5 via the motor, and the power of the input shaft 34 is mounted inside the steering wheel transmission 18 and the front wheel transmission case 5. It is configured to be transmitted to a front wheel differential mechanism (not shown) via the reduction bevel gear 17 which is provided. Next, the steering wheel transmission 18 will be described. As shown in FIGS. 2 and 1, the standard transmission state in which the power from the traveling transmission 9 is transmitted at the same rotational speed, and the input shaft of the front wheel transmission case 5 by increasing the power from the traveling transmission 9 A steerable wheel transmission 18 that is selectively switchable between two states, that is, a speed-increasing transmission state that is transmitted to 16 is configured. The steering wheel transmission 18 is steered to the outer surface of the input shaft 16 of the front wheel transmission case 5 (the fuselage side case portion 5a) so that the steering wheel transmission 18 is located on the rear wheels 2a and 2b side of the front wheel transmission case 5. Wheel transmission 1
8 is connected, and the output cylinder shaft 35 (corresponding to the output shaft) of the steered wheel transmission 18 and the input shaft 16 of the front wheel transmission case 5 are connected. A planetary gear type speed increasing transmission mechanism 36 is provided between the input shaft 34 and the output cylinder shaft 35, and the cylinder portion 37a of the planetary gear support member 37 of the speed increasing transmission mechanism 36 is spline-engaged. A clutch member 38 is attached so as to be integrally rotatable and slidable. This allows the input shaft 3
When the clutch member 38 is engaged with the claw portion 40 supported by the rotary member 39 on the rotating shaft 39, the input shaft 34 and the planetary gear support member 37 are interlockingly connected so as to rotate integrally, and the input shaft 34 of the input shaft 34 is rotated. The standard transmission state is achieved in which power is transmitted to the output cylinder shaft 35 at the same rotation speed. When the clutch member 38 is engaged with the stopper 42 fixed to the transmission case 41, the planetary gear support member 37 is fixed so as not to rotate, and the power of the input shaft 34 is accelerated and transmitted to the output cylinder shaft 35. It will be in the speed increasing transmission state. It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall side view of an agricultural tractor FIG. 2 is a cross-sectional view of a steering wheel transmission device [Description of symbols] 1a, 1b Steering wheels 2a, 2b Non-steering wheel 3 Connection portion 5 Steering wheel support member 16 Steering wheel support member input shaft 18 Steering wheel transmission 35 Output shaft of steering wheel transmission [procedure correction 2] [correction target document name] drawing [correction target item name] Fig. 1 [Correction method] Change [Correction content] [Fig. 1] [Procedure amendment 3] [Document name to be amended] Drawing [Item name to be amended] Figure 2 [Correction method] Change [Content of amendment] [Figure 2] [Procedure Amendment 4] [Amendment Document Name] Drawing [Amendment Item Name] Figure 5 [Amendment Method] Deleted [Procedure Amendment 5] [Amendment Document Name] Drawing [Amendment Item Name] Figure 4 [Amendment Method] Deleted [Procedure Amendment 6] [Name of Documents to Amend] Drawing [Name of Item to Amend] Figure 3 [Method of Amendment] Delete

Claims (1)

Claims: A pair of left and right steering wheels (1a) are provided at one end of the vehicle body in the front-rear direction.
(1b), a pair of left and right unsteered wheels (2a), (2
b), a non-steering wheel (2a), (2b) side of the end of the vehicle body is provided with a connecting portion (3) for detachably connecting the working device, the steering wheel (1a), A standard transmission state in which the average peripheral velocity of (1b) and the average peripheral velocity of the non-steering wheels (2a) and (2b) are the same or substantially the same, and the steering wheel (1
a) and (1b), the average peripheral speed is set to the unsteered wheel (2
a) and (2b) are provided with a steerable wheel transmission (18) which is selectively switchable to a speed increasing transmission state in which the steered wheel transmission (18) is a gear-shifting machine. The steering wheel (1a),
The steering wheel transmission device (18) is arranged at a position on the steering wheel support member (5) supporting (1b) on the side of the non-steering wheels (2a), (2b), and the steering wheel transmission device is arranged. A transmission structure for traveling of a four-wheel drive type working vehicle in which an output shaft (35) of (18) and an input shaft (16) of the steering wheel support member (5) are connected.