JP2824657B2 - Control device for mobile agricultural machine - Google Patents

Description

The present invention relates to a control device in a mobile agricultural machine such as a tractor, and more particularly, to a central differential device interposed in a path for interlocking and connecting a front wheel and a rear wheel. And a control device for a mobile agricultural machine configured to be able to be freely locked and unlocked by operating means.

(B) Conventional technology Conventionally, a control device for controlling locking and unlocking of a central differential device in a vehicle such as an agricultural tractor is disclosed in, for example,
As shown in Japanese Patent Publication No. 285134, when a vehicle turns, when a front wheel turning angle becomes a predetermined angle or more, a lock of a central differential device interposed in a path for interlocking and connecting a front wheel and a rear wheel is released by operating means. It is configured as follows.

Therefore, when the vehicle is going straight, the central differential is in the locked state, the front and rear output shafts are in the directly connected state, and
During turning of the vehicle, the locking of the central differential device is released by the actuating means because the front wheel turning angle has reached a predetermined angle or more, and a differential occurs between the front and rear output shafts.

(C) Problems to be Solved by the Invention However, the control device of the above-described conventional central differential device is:
The central operating device is unlocked only when the front wheel turning angle reaches a predetermined angle or more, so when turning within the range where the front wheel turning angle does not reach the predetermined angle, the central operating device remains locked and outputs front and rear. Since the shaft differential does not occur, problems such as early wear of the tire, an increase in the minimum turning radius, and a deterioration in running feeling occur.

Therefore, the present invention uses the front wheel torque detecting means to capture the transition from the straight running state to the turning state as a torque change acting on the front wheels, and to unlock the central differential based on this. It is an object of the present invention to provide a control device for a mobile agricultural machine that has solved the above-mentioned problems.

(D) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances, and for example, when shown with reference to FIGS. 1 to 3, the front wheel (8)
A central differential (60) is interposed in a path for interlocking and connecting the rear wheels (9), and the central differential (6) can be freely locked and released by an operating means (48). In the mobile agricultural machine (1) configured, the speed is set so that the peripheral speed of the front wheel (8) is slightly faster than the peripheral speed of the rear wheel (9) in a straight running state of the aircraft. A power transmission mechanism (66, 81, 70, 85) is interposed in a power transmission path between the central differential (60) and the front wheel (8) to detect torque acting on the front wheel (8). The front wheel torque detecting means (18) and the body which has detected the positive torque detected by the torque detecting means (18) are held in a position where the central operating device (60) is locked by the operating means (48) during straight running. And the torque detecting means (18) detects the reverse torque when the vehicle is turning. The motion means (48), characterized by comprising a, a switching means (14a) for emitting a signal to release the central differential device (60).

(E) Operation Based on the above configuration, the speed is set so that the peripheral speed of the front wheel (8) is slightly faster than the peripheral speed of the rear wheel (9) in the straight running state of the aircraft. When 1) is in the straight running state, the central differential device (60) is held in the locked state by the operating means (48), so that the front wheel (8) and the rear wheel (9) are in the directly connected state, The torque detecting means (18) detects a positive torque.

When the mobile agricultural machine (1) starts turning by steering,
Due to a difference in turning radius between the front wheel (8) and the rear wheel (9), the front wheel (8) is pushed by the rear wheel (9) with an increase in the turning radius. In this state,
The front wheel torque detecting means (18) which has detected the positive torque until then detects the reverse torque and outputs a torque detection signal to the switching means (14a). Then, the switching means (14a) receives the torque detection signal and determines a change from the positive torque to the reverse torque. Based on this, a release signal is output from the switching means (14a) to the operating means (48), and the operating means (48) is operated, and therefore, the lock of the central differential (60) is released. Thereby, the mobile agricultural machine (1) turns smoothly.

When the mobile agricultural machine (1) is traveling straight, the front differential (83) is held in a locked state by the action of positive torque, and the left and right front wheels (8) and (8) do not differentially move. The front wheels (8) and (8) are driven by receiving the same torque. On the other hand, when the mobile agricultural machine (1) starts turning, the front differential (83) is unlocked by the action of the reverse torque,
The left and right front wheels (8) and (8) are differential, so that the mobile agricultural machine (1) turns smoothly.

The positive torque is a torque from the central differential (drive) side to the front wheels (driven), and the reverse torque is a torque from the front wheels (driven) to the central differential (drive). It shows.

Further, the reference numerals in parentheses are for referring to the drawings, but do not limit the configuration in any way.Also, even if the reference numerals are the same, they are described based on the claims. The names may differ from the names of the embodiments shown.

(F) Example Hereinafter, an example according to the present invention will be described with reference to the drawings.

FIG. 7 shows a side view of the agricultural tractor 1 embodying the present invention, in which 2 is an engine, 3 is a clutch case, 5 is an intermediate case, 6 is a transmission case, 7 is a PTO output shaft,
Reference numeral 8 denotes a front wheel, and 9 denotes a rear wheel. A front part of the fuselage where the engine 2 is disposed and a rear part of the fuselage where the driver's seat 10 is disposed are connected by an intermediate case 5, and the upper surface of the intermediate case 5 is formed on a flat surface 11. Then, the driver can put his / her feet above the driver.

Next, the details of the present invention will be described with reference to FIG.

On a drive shaft 13 erected at the center of the flywheel 12 of the engine 2, a pipe-shaped traveling main shaft 16 which is connected to and disconnected from the flywheel 12 by a clutch 15 is supported. A distribution shaft 21 in which a large gear 19 meshed with a gear 17 fixed to the traveling main shaft 16 and another small gear 20 are fixedly supported by the clutch case 3 and separate from a large gear 22 meshed with the large gear 19. A shuttle shaft 25 on which the small gear 23 is supported is supported by the clutch case 3, and the reverse idle gear 26 is
The clutches 22a and 23a are interposed between the shuttle shaft 25 and the large gear 22 and the small gear 23.

Further, an idle gear 27 supported at the rear end of the distribution shaft 21 is provided.
PTO drive gear 29 fixed to the rear end of PTO drive shaft 13 via
The PTO driven gear 30 is meshed with the
It is supported by the PTO clutch shaft 31, and the PT
It is connected to the O clutch shaft 31.

Further, a distribution shaft 33 extends rearward through a joint 34 on the shuttle shaft 25, is supported by the intermediate case 5, and a PTO drive shaft 36a extends rearward through a joint 35 on the PTO clutch shaft 31. The PTO is inserted into the transmission case 6 through a joint 37 supported on a wall between the intermediate case 5 and the transmission case 6.
A drive shaft 36b is provided, and a four-speed transmission mechanism 39 is interposed between the PTO drive shaft 36b and a rear end of the PTO drive shaft 36b.
It is connected to a PTO output shaft 7 that penetrates the rear wall of the transmission case 6 through 40a and 40b.

Further, a four-stage transmission mechanism 41 constituted by a gear train and a dog clutch is disposed on the distribution shaft 33 and the pipe-shaped main transmission shaft 44 supported by the PTO drive shaft 36a. Transfer gear 42 fixed to the rear end of main transmission shaft 44
A gear 45 that is adjacent to the rear of the main transmission shaft 44 and is supported at the front of a subtransmission shaft 43 that is supported by the PTO drive shaft 36a, and a dog clutch 46 that is slidably mounted; The distribution shaft 33
A first auxiliary transmission mechanism 49 is formed by a reduction shaft 47 provided on the rear side adjacent to the axis and a pair of gears fixed thereto, and is fixed to an intermediate portion of the auxiliary transmission shaft 43. Transfer gears 50 and 51, a twin transfer gear 53 pivotally supported by a front wheel drive shaft 52 described later, and a twin transfer gear 55 meshed with the twin gear 53 and pivotally supported at the rear end of the subtransmission shaft 43. And transfer gears 51 and 55
And a front cylindrical portion 62a of the differential case 62 described later.
A second sub-transmission mechanism 59 is formed by gears 56a and 56b pivotally supported by (see FIG. 5) and a dog clutch 76 slidably mounted.

Next, the central differential device 60 will be described with reference to FIGS.

The support shaft 61 is adjacent to the rear of the reduction shaft 47 and the intermediate case 5
Both ends are pivotally supported, and a differential case is
A cylindrical portion 62a at the front end of the shaft 62 is pivotally supported.
, The front bevel gear 63 is spline-locked, and further, the rear bevel gear 65 is pivotally supported by the support shaft 61 at the rear thereof,
A rear portion of the rear bevel gear 65 is formed in the cylindrical portion 65a,
A front wheel drive gear 66 is spline-locked to the rear end of the cylindrical portion 65a. Further, a pair of differential bevel gears 67 are engaged with the front and rear bevel gears 63, 65, and the differential bevel gears 67, 67 are pivotally supported by the differential case 62 via pins 69, 69, and are provided behind the differential case 62. The side cylindrical portion 62b is the rear bevel gear 65
The rear wheel drive gear 70 is spline-locked to the rear end of the support shaft 61.

Further, a round hole 71 is provided in the rear cylindrical portion 62b of the differential case 62, and a concave portion 72 is provided in the cylindrical portion 65a of the rear bevel gear 65 at a position facing the circular hole 71. Tubular part 62b
A sleeve 73 is slidably mounted on the outer peripheral surface of the ball, a ball 75 is inserted into the round hole 71, and the sleeve 73 is moved onto the round hole 71. The differential case 62 and the rear bevel gear 65 are fixed to each other while being fixed to the inner peripheral surface.

Further, as described above, the gears 56a and 56b
A dog clutch 76, which is rotatably supported by the cylindrical portion 62a and engages with the gears 56a, 56b, is spline-locked to a ring 77 which is spline-locked to the cylindrical portion 62a (the ring 77 in the above description). Has been omitted). Reference numeral 79 denotes a retaining ring that determines the axial positions of the gears 56a and 56b and the ring 77, and reference numeral 80 denotes a retaining ring that determines the positions of the differential case 62 and the front wheel drive gear 66 with respect to the rear bevel gear 65.

A gear 81 is meshed with the front wheel drive gear 66, the front wheel drive shaft 52 is attached to the gear 81, the intermediate case 5 is penetrated forward, and the front wheel differential gear 83 is connected to the front wheel differential device 83 through the joints 82a and 82b. The differential 83 is connected to the left and right front wheels 8
It is connected to. A gear 85 is meshed with the rear wheel drive gear 70, and the gear 85 is connected to the rear wheel differential device via a shaft 86.
The differential 87 is connected to the left and right wheels 9 via a brake 89.

Further, in the locked state of the central differential device 60, the peripheral speed of the front wheel 8 is slightly faster than that of the rear wheel 9 due to the meshing gear ratio of the gears 66, 81, 70, 85 and the like. Is set so that straightness can be improved. Further, a detection sensor 18 is provided at the rear end of the front wheel drive shaft 52.
The detection sensor 18 is configured to detect forward / reverse torque acting on the drive shaft 52 and output a detection signal to a microcomputer 41 described later.

As shown in FIGS. 3 and 6, the front wheel differential device 83 includes a friction disc 109, a pressure ring
112, delivery spring 113 and friction plate 1
A non-stop device 57 including 15 is incorporated, and is configured to engage the bevel gear 106 and the front differential case 103. Note that 107 is a tapered roller bearing, 110 is a ring gear, and 116 is a pinion shaft.

Therefore, the drive shaft 13 and the PTO drive shaft 36 are connected to the PTO output shaft 7.
aThe rotational force of the engine 2 is transmitted via the four-speed transmission 39, the PTO drive shaft 36b, and the like. Here, a four-speed transmission
The gear is shifted four steps by 39. Next, for the front and rear wheels 8, 9, the positive rotational force of the engine 2 is transmitted to the joint 34 via the clutch 15, the traveling spindle 16, the clutch 22a, the shuttle shaft 25, etc., and the clutch 15, the traveling spindle 16, Shaft 21, clutch 23
a, the reverse rotational force is transmitted to the joint 34 via the shuttle shaft 25 and the like. Then, from the distribution shaft 33, through the four-speed transmission mechanism 41, the first sub-transmission mechanism (two-stage transmission) 49, the second sub-transmission mechanism 59, the dog clutch 76, and the like, the forward and reverse rotational force that has been shifted is changed to the central differential. apparatus
It is transmitted to 60. Note that the rotational force can be connected and disconnected by the clutch 15 and also by the simultaneous connection and disconnection of the clutches 22a and 23a.

Next, front wheel drive gear 66, gear 81 of central differential device 60,
The rotational force of the engine 2 is transmitted to the left and right front wheels 8 via the front wheel drive shaft 52, the joints 82a and 82b, the front wheel differential 83, and other transmission devices.

At the same time, the driving force is divided into left and right through a rear wheel drive gear 70, a gear 85, a shaft 86 and a rear wheel differential 87, and the torque of the engine 2 is transmitted to the left and right rear wheels 9 via a brake 89. When the agricultural tractor 1 turns and the outer track is longer than the inner track, the front and rear wheel differentials 83 and 87 make the inner and outer wheels 8 and 9 differential to balance. The operation of the brake 89 allows the agricultural tractor 1 to decelerate and stop.

On the other hand, FIG. 2 is a diagram showing a hydraulic circuit for operating each operating device of the agricultural tractor 1, and a hydraulic pump P driven by the engine 2 communicates with the tank T via a filter 91, Through a relief valve 92 and a priority valve 93, it communicates with an external take-out valve 94. The external take-out valve 94 communicates with a working machine horizontal control hydraulic cylinder 95 that constantly controls the posture of the working machine, and also communicates with a working machine elevating hydraulic cylinder 96. Further, the priority valve 93 has an electromagnetic valve 24, and the electromagnetic valve 24 is
Communicates with 8.

The operating means 48 has a rail 38, and at one end of the rail 38, a cylinder portion 101 on which hydraulic pressure from the oil passage 100 acts is formed, and at the other end, a spring 28 abuts. And is configured to be able to withstand the oil pressure from the oil passage 100. A fork 34 is pivotally supported on the rail 38 via a pin 102, and the fork 34 is
It is connected to.

As shown in FIG. 1, a microcomputer 14 (hereinafter referred to as a microcomputer) mounted on the agricultural tractor 1
The detection sensor 18 is connected to the input port, and the above-described electromagnetic switching valve 24 and solenoid 24a are connected to the output port. Further, the microcomputer 14 is provided with switching means 14a, and the switching means 14a is provided with a microcomputer.
An operation signal is output to the solenoid 24a based on the torque detection signal from the detection sensor 18 input to the.

In the present embodiment, since the agricultural tractor 1 is traveling straight, the peripheral speed of the front wheel 8 is slightly faster than that of the rear wheel 9 when the agricultural tractor 1 is traveling straight, so that the tractor 1 is slightly slipped. Because it is in a state of pulling, the detection sensor 18
Detects a positive torque (see FIG. 4) and outputs an electric signal based on the positive torque to the microcomputer 14. Then, the microcomputer 14 receives the positive torque detection signal and switches the switching means 14.
A signal is issued from a to the solenoid 24a to lock the central differential 60. Therefore, the electromagnetic valve 24 is turned off, the hydraulic pressure does not act on the cylinder portion 101, and the spring 2
8 is applied to the sleeve 7 via the rail 38 and the fork 34.
3, the sleeve 73 is located outside the ball 75, and the ball 75 is fixed by the round hole 71, the concave portion 72, and the inner peripheral surface of the sleeve 73. As a result, the rear bevel gear 65 and the differential case 62 are locked, and there is no difference in the rotational speed between the front and rear wheel drive gears 66, 70, so that the front wheel 8 and the rear wheel 9 are directly connected.

When the agricultural tractor 1 starts turning, the front wheel 8 is pushed by the rear wheel 9 as the turning radius increases, for example, due to a difference in the turning radius between the front wheel 8 and the rear wheel 9. Therefore, a reverse torque acts on the front wheel drive shaft 52. As a result, the detection sensor 18 detects the reverse torque (see FIG. 4), converts the reverse torque into an electric signal based on the torque, and outputs the electric signal to the microcomputer 14. Upon receiving the reverse torque detection signal input to the microcomputer 14, the release means 14a provided in the microcomputer 14 outputs a differential lock release signal to the electromagnetic valve 24. Then, the electromagnetic valve 24 is turned on, and the hydraulic pressure generated by the hydraulic pump P is applied to the oil passage 100.
And acts on the cylinder part 101 via. Then, the hydraulic pressure acts on the rail 38 against the urging force of the spring 28, and moves the sleeve 73 toward the front wheel drive gear 66 via the rail 38 and the fork 34. Then, the ball 75 is
Since the pressure contact state by the ball 73 is released, the locked state of the differential case 62 and the rear bevel gear 65 by the ball 75 is released. Therefore, a differential state is attained that can freely cope with the rotational speed difference between the front and rear wheel drive gears 66 and 70.

When the electromagnetic valve 24 is turned on and the central differential 60 is unlocked while the agricultural tractor 1 is turning, the detection sensor 18 detects a positive torque again (see FIG. 4). The valve 24 is switched to the OFF state. Then, no hydraulic pressure acts on the cylinder portion 101, and the urging force of the spring 28 acts on the sleeve 73 via the rail 38, the pin 102, and the fork 34. And
Due to the urging force, the sleeve 73 moves to the outside of the ball 75 and tries to press and engage the ball 75 with the concave portion 72. At this time, the peripheral speed difference between the rear bevel gear 65 and the differential case 62 is reduced. Due to the large size, the sleeve 73 cannot be moved by the biasing force of the spring 28, and therefore, the central differential 60 is held in the unlocked state.

Further, when the agricultural tractor 1 finishes turning and goes straight again, there is no peripheral speed difference between the rear bevel gear 65 and the differential case 62, so that the sleeve 73 moves to the outside of the ball 75 by the urging force of the spring 28. And the ball 75
, The differential case 62 and the rear bevel gear 65 are locked. As a result, the central differential 60 is locked again, and the front and rear wheels 8, 9 obtain effective traction.

On the other hand, when the tractor 1 is traveling straight, the left and right front wheels 8,8
Receive the same torque because the front wheel differential 83 is held in the locked state. That is, when traveling straight, the pinion shaft 116 operates in the rotation direction, so that the pressure ring 112 is pressed and moved in the left and right direction, whereby the friction plate 109 and the friction disc 115 are pressed and engaged, and the left and right bevel gears 111, 111 and the case 103 are moved. Since the left and right front wheels 8, 8 rotate together based on the same torque, the tractor 1 can perform stable straight running. Further, when the tractor 1 turns, the front wheel 8 is pressed by the rear wheel 9 so that a reverse torque is applied. Therefore, the pressing force of the pressure ring 112 on the friction plate 109 and the friction disk 115 is released. , Case 103 and bevel gear 11
And a difference in peripheral speed occurs between the left and right front wheels 8, 8, so that the tractor 1 can turn smoothly.

(G) Effects of the Invention As described above, according to the present invention, the central differential device (60) is configured to switch between the locked state and the unlocked state based on the torque detection signal from the front wheel torque detecting means (18). Therefore, when turning, the lock of the central differential (60) is properly released to secure the required peripheral speed difference between the front wheel (8) and the rear wheel (9), and the vehicle turns smoothly immediately after entering the turning state. Therefore, inconveniences such as early wear of the tire and an increase in the minimum turning radius can be reliably prevented, and the running feeling can be improved. In addition, the central differential (60) can be properly switched between locked and unlocked when necessary, without being limited to the front wheel turning angle. For example, when running on uneven terrain, the front wheels may be uneven due to uneven road surfaces. Even if (8) rotates a little, the lock of the central differential (60) is not released each time, and the reliability can be improved and the operation feeling can be greatly improved.

[Brief description of the drawings]

1 is an electric circuit diagram of a control device according to the present invention, FIG. 2 is a hydraulic circuit diagram thereof, FIG. 3 is a diagram showing an entire power transmission device embodying the present invention, and FIG. 5 is a cross-sectional view of the central differential device cut along a plane including the axis of the support shaft, and FIG. 6 is a cross-sectional view of the front differential device. FIG. 7 is an overall side view of an agricultural tractor capable of implementing the present invention. 1 ... moving agricultural machine (agricultural tractor), 8 ... front wheel, 9 ... rear wheel, 14a ... switching means, 18 ... front wheel torque detecting means (detection sensor), 48 ... operating means, 57 ... non-slip device , 60 ... Central differential, 83 ... Front differential (front wheel differential).

Claims (1)

(57) [Claims] 1. A mobile agricultural machine comprising a central differential device interposed in a path for interlocking and connecting a front wheel and a rear wheel, and wherein the central differential device can be freely locked and released by operating means. A power transmission mechanism for setting the speed so that the peripheral speed of the front wheels is slightly faster than the peripheral speed of the rear wheels in a straight running state of the vehicle; and A front wheel torque detecting means for detecting torque acting on the front wheels, interposed in the power transmission path of the vehicle; and And a switching means for transmitting a signal for releasing the central differential device to the operating means when the aircraft detects turning torque when the torque detecting means detects a reverse torque. That I have A control device for a mobile agricultural machine, which is characterized by the following.