JP2003267258A - Steering device of traveling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a power transmission shaft for receiving and transmitting a power to a steering part in a steering device for steering a vehicle by providing additional rotations in directions reverse to each other to right and left differential devices. <P>SOLUTION: In the vehicle, a main drive shaft 36 rotatingly driven through a traveling gear shifting mechanism is connected to right and left traveling drive shafts 38L and 38R through right and left differential devices 39L and 39R. The vehicle comprises a hydraulic transmission device 53 for providing the additional rotations in directions reverse to each other to the right and left differential devices. The main drive shaft and the right and left traveling drive shafts are installed in a frame housing having a PTO shaft 4, and the pump shaft 54a of the hydraulic transmission device is rotatingly driven through the PTO drive shaft 30 for transmitting power to the PTO shaft. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a main drive shaft that is rotationally driven by an engine via a travel transmission mechanism and left and right travel drive shafts that are connected to left and right final travel drive means. Steering device for steering a vehicle in a traveling vehicle that is connected via a hydraulic transmission device for steering the vehicle by applying additional rotations in opposite directions to the left and right differential devices. It is about.

[0002]

BACKGROUND OF THE INVENTION Such a steering device is disclosed in Japanese Patent Laid-Open No. 2001-4.
It is already known from Japanese Patent No. 8043, and by changing and controlling the inclination angle of the pump swash plate in the hydraulic transmission device, including the reverse rotation from the neutral position, the left and right traveling drive shafts are provided with a rotational speed difference, and the vehicle is moved to the left and right. Turn in any direction with an arbitrary turning radius.

In the steering apparatus disclosed in the above publication, the engine is installed in the front part of the vehicle body, and the propeller shaft which is the final transmission shaft of the traveling speed change mechanism is installed in the rear part of the vehicle body. On the other hand, the main drive shaft and the left and right traveling drive shafts, including the left and right differential devices between them, are installed inside the front axle case at the front of the machine body, and the propeller shaft is moved from the propeller shaft by the power transmission shaft along the longitudinal direction of the machine body. While transmitting power to the main drive shaft in the front axle case, a hydraulic power transmission device is installed at the forefront of the machine body, and its pump shaft is installed so that it can be driven to rotate by the engine via the power transmission shaft and the gear reduction device. It is configured so that the motor shaft of the transmission is connected to the left and right differentials in the front axle case so as to provide the required additional rotation in the opposite left and right directions. Therefore, it requires a power transmission shaft for input transmission from the propeller shaft at the rear of the machine to the main drive shaft in the front axle case, and another power transmission shaft for input transmission from the front of the engine to the hydraulic transmission at the front of the machine. Moreover, since a shaft joint is required at both ends of each power transmission shaft, the structure is complicated and the cost is high.

Therefore, the present invention has devised a method of driving a hydraulic power transmission device to eliminate the two power transmission shafts in the conventional one, has a simple structure, and can reduce the cost. Is to provide.

[0005]

SUMMARY OF THE INVENTION A steering apparatus for a traveling vehicle according to the present invention comprises a main drive shaft (36) which is rotationally driven by an engine (1) via a traveling speed change mechanism (28, 29) and left and right final traveling drive means ( 8) Left and right traveling drive shafts (38L, 3
8R) via left and right differential devices (39L, 39R), and hydraulic transmissions for steering the vehicle by applying additional rotations in opposite directions to the left and right differential devices ( 5
In a traveling vehicle provided with 3), the main drive shaft (3
6) and the left and right traveling drive shafts (38L, 38R), PT
The pump shaft (54a) of the hydraulic transmission (53) is provided in the body housing (3) equipped with the O-axis (4).
Is configured to be rotationally driven by a PTO drive shaft (30) that transmits the power of the engine (1) to the PTO shaft.

According to the present invention, the main drive shaft (36) and the left and right traveling drive shafts (38L, 38R) are provided in the same body housing (3) equipped with the PTO shaft (4),
A hydraulic pressure for giving additional rotations in opposite directions to the left and right differential devices (39L, 39R) between the main drive shaft and the left and right traveling drive shafts by the PTO drive shaft (30) that transmits power to the O shaft. Pump shaft (54a) of transmission (53)
Since it is configured to rotate, the power transmission shaft for input transmission from the propeller shaft in the rear part of the machine to the main drive shaft in the front axle case, and the hydraulic transmission device from the engine to the forefront part of the machine. On the other hand, it has a simple structure that does not require the two power transmission shafts that are conventionally provided, such as another power transmission shaft for input transmission.
Significantly reduce manufacturing cost.

The hydraulic transmission (53) is preferably installed on the outer surface of the machine housing (3) because the hydraulic transmission does not interfere with the transmission mechanism in the machine housing.

Further, the hydraulic transmission (53) is preferably installed on the side surface of the body housing (3) at an upper position of the housing. That is, according to this structure, the hydraulic transmission does not interfere with the left and right final traveling drive means, which are the crawlers or the wheels.

The tractor is generally constructed such that the engine is installed in the front of the machine body and the propeller shaft, which is the final shaft of the traveling speed change mechanism, extends into the rear housing. Further, the structure for giving additional rotation to the left and right differential devices for steering the vehicle is particularly suitable for the crawler type. Therefore, in one embodiment of the present invention, the traveling vehicle is a crawler type tractor, and the rear housing (3) of the tractor is selected as the body housing.

In the tractor as described above, it is preferable to adopt a structure in which the rear housing (3) is connected to the rear portion of the transmission case (2) which houses the traveling transmission mechanism (28, 29). That is, according to this structure, compatibility with the conventional general tractor can be obtained by replacing only the rear housing with a rear housing having left and right drive wheels.

Other features and advantages of the present invention can be clearly understood from the following description with reference to the accompanying drawings.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a crawler type tractor equipped with an embodiment of the present invention. The engine 1 is installed in the front part of the fuselage, and the mission case 2 is installed behind the engine 1.
A body is formed by connecting the rear housing 3 and the rear housing 3. A PTO shaft 4 extending rearward from the inside of the rear housing 3 is provided, and a PTO shaft 4 is provided on the rear upper surface of the rear housing 3.
A hydraulic lift device 5 having left and right lift arms 5a for raising and lowering a work machine (not shown) driven by the TO shaft 4 is installed. In order to run the tractor, left and right crawlers 8 are provided around the left and right drive wheels 6 at the rear of the machine body and the left and right idler wheels 7 at the front of the machine body. The seat 9 is installed above the rear part of the machine body, and a steering handle 10 is provided in front of the seat 9. In FIG. 1, 11 is an engine hood, 12 is a radiator attached to the engine 1, 13 is its cooling fan, and 14 is a cabin.

FIG. 2 shows a transmission mechanism provided on the illustrated tractor. A drive shaft 16 connected to the engine flywheel 1a through a buffer joint 15 is provided, and a forward / reverse switching device 18 is provided between the drive shaft 16 and a hollow drive shaft 17 located behind the drive shaft 16. Has been.
The forward / reverse switching device 18 includes a forward hydraulic clutch 19F and a reverse hydraulic clutch 19R provided on the drive shaft 16. Depending on the operation of the forward hydraulic clutch 19F, the gear 20 is connected to the drive shaft 16 to drive the drive shaft. 17 is rotated in the forward direction of the vehicle, and the gear 21 is connected to the driving shaft 16 depending on the operation of the reverse hydraulic clutch 19R, so that an idler gear (not shown) and an intermediate shaft 22 parallel to the driving shaft 16 are formed from the gear 21. The gears 23 and 24 are used to rotate the gear 20 in the opposite direction, thereby rotating the drive shaft 17 in the backward direction of the vehicle.

A driven shaft 25 is arranged below the drive shaft 17, and a hollow counter shaft 26 is arranged behind the drive shaft 17.
A propeller shaft 27 is arranged behind the driven shaft 25. The traveling speed change mechanism includes a drive shaft 17 and a driven shaft 25.
It is composed of a main transmission 28 arranged between them, and an auxiliary transmission 29 arranged between the driven shaft 25 and the propeller shaft 27 and including a counter shaft 26. The forward / reverse switching device 18, the main transmission device 28, and the auxiliary transmission device 29 are installed in the mission case 2.

PT from the engine 1 to the PTO shaft 4
Explaining the O transmission mechanism, a PTO drive shaft 30 having a hollow drive shaft 17 and a counter shaft 26 penetrating therethrough is connected to the rear end of the drive shaft 16. As shown in FIGS. 2 and 3, the PTO drive shaft 30 is connected to a transmission shaft 31 concentrically provided in the rear housing 3, and the transmission shaft 31
A drive shaft 32 is arranged at the rear part, and a PTO clutch 33 configured as a hydraulic clutch is provided between the transmission shaft 31 and the drive shaft 32. Then, between the drive shaft 32 and the PTO shaft 4 which is parallel to the drive shaft 32, a PTO transmission device 3 for performing three-speed gear shifting
4 are arranged. The drive shaft 32 and the PTO shaft 4 are supported by front and rear thereof by a supporting wall portion 3b integral with the rear housing 3 and a rear lid 3c closing an opening at the rear end of the rear housing 3.

As shown in FIGS. 3 and 4, the rear end of the propeller shaft 27 is passed through the front wall 3a of the rear housing 3 to face the inside of the housing 3 and is equipped with a bevel gear 35 having a small diameter.
As shown in FIGS. 2 and 4 and 5, a main drive shaft 36 is arranged along the lateral direction at the front position in the rear housing 3, and on the main drive shaft 36, with respect to the bevel gear 35, A large-diameter bevel gear 37 that is meshed is fixedly installed. Left and right traveling drive shafts 38L and 38R are arranged on the left and right of the main drive shaft 36, and the main drive shaft 36 includes the left and right traveling drive shafts 38L and 38R.
38R via left and right differential devices 39L and 39R. Then, the left and right traveling drive shafts 38L, 38
R is a left and right axle 40L equipped with the left and right drive wheels 6,
40R, gears 4 on the traveling drive shafts 38L, 38R
1, intermediate gear 42 and gear 43 on axles 40L, 40R
Are connected by the left and right reduction gear mechanisms.
In FIGS. 4 and 5, 44 is a planetary gear device housing that is connected to the left and right of the rear housing 3, and 45 is the housing 4.
4 is an axle case connected to the outer end of No. 4.

The left and right differential devices 39L and 39R described above.
Is a carrier 47 including a pair of carrier plates integrally connected to each other by a connecting member 46.
Two planetary gears 49, 50 integrally supported by a pin 48 in a freely rotatable manner, and a sun gear fixedly installed at the end of the main drive shaft 36 and meshing with the planetary gear 49 on the large diameter side. 51 and a drive gear 52 fixedly installed at the ends of the respective traveling drive shafts 38L and 38R and meshing with the planetary gear 50 on the small diameter side. The main drive shaft 36 is decelerated in rotation to each of the left and right traveling drive shafts 38L. , 38R.

As shown in FIGS. 1 and 3, a hydraulic transmission device 53 is installed on the outer surface of one side wall of the rear housing 3 above the front portion of the housing 3 in an inclined posture in which it is slightly raised. This hydraulic transmission device 53 is, as usual, formed by connecting a variable displacement hydraulic pump 54 and a constant displacement hydraulic motor 55 shown in FIG. 2 by a closed circuit.
By changing and controlling the tilt angle of the pump swash plate 54b of No. 4 including reverse rotation from the neutral position, the rotation of the hydraulic motor 55 is arbitrarily controlled including reverse rotation direction. The tilt angle changing control of the pump swash plate 54b is performed by the steering handle 1 shown in FIG.
It is supposed to be performed by rotating 0.

As shown in FIGS. 3 and 6, the PTO drive shaft 30 and the transmission shaft 31 in the PTO transmission mechanism are both the shafts 3 and 3.
They are connected by providing a bevel gear 56 spanning 0 and 31. As shown in FIG. 6, the rear housing 3
Pump shaft 54a of the hydraulic transmission 53 which is thrust into the inside
The bevel gear 58 meshed with the bevel gear 56 is integrally formed at the inner end of the lateral drive shaft 57 connected to the pump shaft 54a, so that the PTO drive shaft 30 can rotate the bevel gear.

As shown in FIGS. 5 and 6, the motor shaft 55a of the hydraulic transmission 53 is also projected into the rear housing 3, and the sideways steering drive shaft 59 is disposed in the upper position of the housing 3. It is connected. Left and right gears 60 are fixed to the steering drive shaft 59, and a gear 61 is integrally formed on one side carrier plate of the carriers 47 of the left and right differential devices 39L and 39R. Drive shaft 59
The upper right gear 60 is directly meshed with the gear 61 provided on the right differential device 39R. On the other hand, the left-side gear 60 on the steering drive shaft 59 has a lateral counter shaft 62 provided in the rear housing 3 and left and right gears 63, 6 respectively.
4 is fixed, the gears 60 and 63 are meshed with each other, and the gear 64 is meshed with the gear 61 provided on the left differential device 39L. Gear 6 provided on the differential device 39L on the left side
1 is rotationally driven. Therefore, when operating the hydraulic transmission 53 by rotating the steering handle 10 of FIG. 1 from the neutral position to the left or right, the left and right differentials 39L and 39R or their carriers 47 are moved in opposite directions. A constant speed of additional rotation is given.

When the steering handle 10 is kept in the neutral position, the hydraulic transmission 53 is kept in the neutral state and exerts a braking action on the carriers 47 of the left and right differential devices 39L and 39R. The left and right traveling drive shafts 38L and 38R are driven at a constant speed at a speed reduction ratio determined by the left and right differential devices 39L and 39R themselves to drive the vehicle straight. On the other hand, when the steering handle 10 is rotated leftward or rightward from the neutral position and the pump swash plate 54b of the hydraulic transmission 53 is tilted leftward or rightward from the neutral position to operate the hydraulic transmission 53, The left and right differential devices 39L and 39 are attached to the carrier 47 that supports the planetary gears 49 and 50.
Since the additional rotations in opposite directions are given to R, the differentials 39L or 39R on one side increase speed and the differentials 39R or 39L on the other side reduce speed by the additional rotations. A rotational speed difference occurs between the traveling drive shafts 38L and 38R, and the vehicle turns left or right. The turning radius is set by changing the tilt angle of the pump swash plate 54b.
By changing the discharge flow rate of No. 4 and changing the rotation speed of the hydraulic motor 55, change control can be performed to an arbitrary value. If both hydraulic clutches 19F and 19R of the forward / reverse switching device 18 are set to the neutral state, the main drive shaft 36 is stopped, and the brake 85 described later is activated, the hydraulic transmission device 53 is activated to spin-turn the vehicle. Can be made.

The traveling speed change mechanism installed in the mission case 2 will be described with reference to FIG.
Are four gears 66, 67, 68, 69 on the drive shaft 17.
Is fixedly installed, and the four gears 70,
71, 72, 73 are loosely fitted and installed, and these gears 66-
69 and 70-73 corresponding to each other are meshed with each other, and two double synchronizing clutches 74 and 75 are provided on the driven shaft 25. Dual synchronous clutch 74,
By selectively operating 75 to selectively connect one of the gears 70-73 to the driven shaft 25, a first-fourth speed shift can be obtained.

The driven shaft 25 and the counter shaft 26 are connected by a reduction gear mechanism 76. The auxiliary transmission 2
In the reference numeral 9, two gears 77 and 78 are fixedly installed on the counter shaft 26, and a speed change gear 80 connected to a gear 77 on the small diameter side of these gears via a gear reduction mechanism 79 is provided outside the counter shaft 26. The transmission gear 8 is provided on the propeller shaft 27.
The shift gear 81 which can be selectively meshed with 0 is installed, the transmission gear 82 which is meshed with the gear 78 is loosely fitted, and the transmission gear 82 is selectively coupled to the propeller shaft 27 from the neutral position. The double clutch 83 is selectively displaced between a position where the propeller shaft 27 is directly connected to the driven shaft 25 and a position where the propeller shaft 27 is directly connected to the driven shaft 25.
The shift gear 81 and the multiple clutch 83 are interlockingly connected to each other. When the shift gear 81 meshes with the gear 80, the first speed (creep speed) is obtained. When the multiple clutch 83 couples the speed change gear 82 to the propeller shaft 27, the shift gear 81 becomes 2 The third speed can be obtained by directly connecting the propeller shaft 27 to the driven shaft 25 by the clutch 83.

Another gear 84 is fixedly installed on the propeller shaft 27, and a parking brake 85 for braking the vehicle by braking the gear 84 is provided. That is, as shown in FIG. 7, an opening 2a is formed in the bottom wall of the mission case 2, and a brake case 86 that closes the opening 2a is attached to the bottom wall of the mission case 2. The brake case 86 integrally includes a support shaft 88 that supports a freely rotatable intermediate gear 87 and a gear 89 that meshes with the intermediate gear 87.
0 is supported, and the intermediate gear 87 is engaged with the gear 84, and the intermediate gear 87 is mounted on the bottom wall of the mission case 2. The parking brake 85 has a support metal 91 fixedly installed on the brake shaft 90 and a brake case 86 that support a plurality of friction elements, each of which is slidable, and the friction elements are rubbed by the action of a disc spring 92. It is configured to be engaged to obtain braking of the brake shaft 90.

In order to release the braking action of the parking brake 85, a piston 94 for compressing the disc spring 92 via a ring 93 is provided while being supported by the support metal 91.
An oil passage 95 formed in the brake shaft 90 is opened behind the piston 94. The braking action of the parking brake 85 is supposed to be carried out by stepping on the pedal 96.
An electromagnetic directional control valve 98 whose position is changed via 7 is inserted in an oil passage connecting the hydraulic pump 99 and the oil passage 95. The electromagnetic directional control valve 98 applies a hydraulic pressure to the piston 94 to release the parking brake 85 at a position I.
And a position II that is displaced by the depression of the pedal 96 to release the action of the same hydraulic pressure and apply the braking action to the parking brake 85.

Specific structures of the PTO clutch 33 and the PTO transmission 34 provided in the PTO transmission mechanism will be described with reference to FIG. The PTO clutch 33 has a support metal 100 fixedly installed on the rear end of the transmission shaft 31 and a clutch housing 101 fixedly installed on the front end of the drive shaft 32. Support the spring 10 in the clutch housing 101.
2 is provided with a piston 103 that is biased backward, and the piston 103 is moved forward by the action of hydraulic pressure to obtain engagement between the friction elements and engage the clutch. The oil passage 104 for applying a hydraulic pressure to the piston 103, and the oil passage 105 for guiding the lubricating oil to the friction element portion of the PTO clutch 33 are provided in the drive shaft 32.
Has been drilled.

The PTO transmission 34 has three drive shafts 32 mounted on it.
The transmission gears 106, 107, 108 are fixedly installed and three transmission gears 109, 110, 1 are mounted on the PTO shaft 4.
11 is loosely fitted and the corresponding ones of these speed change gears are engaged with each other, and the speed change gears 109-1 are mounted on the PTO shaft 4.
It is configured such that a clutch metal member 112 for selectively connecting one of 11 to the PTO shaft 4 is provided.

In FIG. 2, 113 is a hydraulic pump installed on the drive shaft 16. 11 in FIGS.
Reference numeral 4 denotes a gear that is fixedly installed on the transmission shaft 31, and extracts power from the transmission shaft 31 and guides it to an upper surface position of the rear housing 3 to drive a hydraulic pump (not shown).

The hydraulic transmission device 53 is the rear housing 3
It is also possible to install the pump shaft and the motor shaft on the upper surface of the vehicle by extending them in the rear housing 3 along the vertical direction. In that case, a bevel gear is fitted to a transmission shaft connected to the motor shaft or an extension thereof, and the left and right steering drive shafts transmitted from the bevel gear to the left and right differential devices 39L and 39R are connected to the bevel gear. Assuming that the bevel gears that mesh with each other from the left side and the right side are fitted, the left and right steering drive shafts can be rotated in opposite directions without providing the counter shaft 62 as described above. Also, left and right differential devices 39L and 39R
Is not limited to the one having the above-mentioned structure, but is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-31
As disclosed in Japanese Patent No. 0433, a ring that rotatably supports a planetary gear that is rotatably supported by a carrier that is fixed to left and right traveling drive shafts and a sun gear that is fixed to a main drive shaft. Meshes with the internal toothed wheel formed on
It is also possible to form a gear on the outer peripheral surface of the ring, which receives power from the steering drive shaft.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a crawler type tractor equipped with an embodiment of the present invention.

FIG. 2 is a mechanism diagram showing a transmission mechanism provided in the tractor.

FIG. 3 is a vertical sectional side view of a rear housing of the tractor.

FIG. 4 is a partially developed vertical sectional plan view showing a lower half portion of the rear housing.

FIG. 5 is a partially expanded transverse rear view of the rear housing.

FIG. 6 is a partially developed vertical plan view showing an upper half portion of the rear housing.

FIG. 7 is a vertical cross-sectional side view showing a parking brake provided on the tractor.

[Explanation of symbols]

1 engine 2 mission case 3 rear housing 4 PTO axis 8 crawlers 10 Steering handle 27 propeller shaft 28 Main transmission 29 Auxiliary transmission 30 PTO drive shaft 31 Transmission shaft 36 Main drive shaft 38L, 38R traveling drive shaft 39L, 39R differential gear 40L, 40R axle 47 career 49,50 planetary gears 51 sun gear 52 drive gear 53 Hydraulic transmission 54 Hydraulic pump 54a pump shaft 54b Pump swash plate 55 Hydraulic motor 55a motor shaft 56 bevel gears 57 drive shaft 59 Steering drive shaft 60 gears 61 gears 62 counter axis 63, 64 gears

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2B043 AA03 AB02 BA02 BA05 BB01                       DB04 DB18                 3D042 AA06 AB10 AB12 BA02 BA07                       BA08 BA13 BA18 BB02 BB03                 3D043 AA06 AB11 BA00 BA06 BC03                       BC04 BC09 BC11 BC16                 3D052 AA16 AA18 EE01 FF01 FF02                       GG03 JJ02 JJ03 JJ10 JJ21                       JJ31 JJ35

Claims (5)

[Claims] 1. A traveling transmission mechanism (2) using an engine (1).
A main drive shaft (36) rotatably driven via a drive shaft (8, 29) and left and right traveling drive shafts (38L, 38R) connected to the left and right final traveling drive means (8). 39
L, 39R), and is provided with a hydraulic transmission (53) for steering the vehicle by applying additional rotations in opposite directions to the left and right differentials, Main drive shaft (36) and left and right traveling drive shafts (38L,
38R) is provided in a body housing (3) equipped with a PTO shaft (4) to transmit the power of the engine (1) to the PTO shaft through the pump shaft (54a) of the hydraulic transmission (53). A steering device characterized by being configured to be rotationally driven by a PTO drive shaft (30). 2. The steering apparatus according to claim 1, wherein the hydraulic transmission device (53) is installed on an outer surface of the body housing (3). 3. The steering apparatus according to claim 2, wherein the hydraulic transmission (53) is installed on a side surface of the body housing (3) at a position above the housing. 4. The traveling vehicle is a crawler type tractor,
The steering apparatus according to claim 1, 2 or 3, wherein the body housing is a rear housing (3) of the tractor. 5. The steering apparatus according to claim 4, wherein the rear housing (3) is connected to a rear portion of a transmission case (2) in which the traveling transmission mechanism (28, 29) is installed.