JP2007321823A - Working vehicle transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need for an oil tank for operating oil by devising the construction of incorporating a toroidal transmission mechanism into a transmission case. <P>SOLUTION: The transmission device comprises the transmission case 1 partitioned with front and rear partition walls 2, 3, and the toroidal transmission mechanism 4 assembled on a shaft 10 arranged therein at its upper side. A travel driving input shaft 11 for inputting engine power to the toroidal transmission mechanism 4, a PTO transmission shaft 12 and a front wheel driving shaft 13 are provided on the lower side of the toroidal transmission mechanism 4, and the operating oil is stored in the front and rear partition walls 2, 3 of the transmission case 1 in the state that the toroidal transmission mechanism 4 is not immersed therein. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission for a power transmission unit in a work vehicle such as a tractor or a front loader provided with a ground work machine.

In particular, a transmission incorporating a toroidal transmission mechanism as a continuously variable transmission mechanism with good power transmission efficiency at low speeds is used in work vehicles.
Japanese Patent No. 3443724 JP 2005-273734 A

  Since the hydraulic oil used in the toroidal transmission mechanism is different from ordinary mission oil, an isolation space for incorporating the toroidal transmission mechanism is provided in the mission case. The prior art described in the above patent document also incorporates a toroidal speed change mechanism in the isolation space. However, this toroidal speed change mechanism cannot be immersed in oil, and the working oil does not like foaming. The oil is stored in a separate oil tank and supplied by a pump.

  Accordingly, an object of the present invention is to eliminate the need for an oil tank for hydraulic oil by devising a configuration for incorporating a toroidal transmission mechanism in a mission case.

The above object of the present invention is achieved by the following configuration.
That is, the transmission case (1) is partitioned by the front and rear partition walls (2) and (3), and the toroidal transmission mechanism (4) is assembled to the shaft (10) arranged at the upper position inside the transmission case. A travel drive input shaft (11) for inputting engine power to the toroidal transmission mechanism (4), a PTO transmission shaft (12), and a front wheel drive shaft (13) are provided below, and the toroidal transmission mechanism (4) is immersed in hydraulic oil. A transmission for a work vehicle characterized in that it is configured to be stored in the front and rear partition walls (2) and (3) of the transmission case (1) without being disengaged.

  Since the present invention is configured as described above, the traveling drive input shaft 11, the PTO input shaft 12, and the front wheel drive shaft 13 do not stir the working oil so much without foaming the toroidal transmission mechanism 4 directly on the working oil. Hateful.

  As a result, the hydraulic oil can be stored in the mission case 1, the hydraulic oil dedicated oil tank can be omitted, and the manufacturing cost can be reduced.

Hereinafter, an embodiment in which the present invention is implemented in an agricultural tractor will be described with reference to the drawings.
As shown in FIG. 1, the mission case 1 is constructed integrally by connecting three cases of a front case 1 a, a middle case 1 b, and a rear case 1 c from the front.
The front case 1a has a front partition wall 2 and a rear partition wall 3, and a variator shaft 10, a travel drive input shaft 11, a PTO transmission shaft 12, and a front wheel drive shaft 13 are pivotally supported in the front and rear partition walls 2, 3 from above. is doing. A main input shaft 14 directly connected to the output shaft of the engine E is mounted on the axial center line in front of the variator shaft 10.

  The gear 15 fixed to the main input shaft 14 on the inner side of the front bulkhead 2 meshes with the large diameter gear portion of the large and small gear 16 fixed to the lower travel drive input shaft 11 to increase speed transmission, and the small diameter gear of the large and small gear 16 The gear 18 fixed to the lower PTO input shaft 12 is meshed with the lower part, and is decelerated and transmitted.

The lowermost front wheel drive shaft 13 transmits power to the front front differential shaft 17 by transmission from the middle case 1b described later. The front differential shaft 17 drives the left and right front wheels 20 via the front differential gear 19. (See Figure 3)
The toroidal speed change mechanism 4 attached to the variator shaft 10 is fixed to the two output disks 4a and 4a that rotate integrally with the variator shaft 4 and the lower travel drive input shaft 11 located at the center of both the output disks 4a and 4a. A plurality of input disks 4b and 4b that rotate together with a gear 23 that meshes with the gear 21 via a relay gear 22, and a plurality of rotating rollers that are supported at the tip of the cylinder piston between the output disks 4a and 4a and the input disks 4b and 4b. A sandwiching structure (variator mechanism) is adopted. Then, by changing the positions of the plurality of rotating rollers and cylinder pistons (hereinafter referred to as power rollers 24) by hydraulic operation, the tilt angles of the rollers are changed, and the input disks 4b and 4b are changed to the output disks 4a and 4a. The transmitted power transmission ratio is changed, and the rotation of the variator shaft 10 is changed. This speed change transmission efficiency is good at about 80 to 90%, and is characterized by high transmission efficiency especially at a low speed.

  Oil seals 82, 83, 84, and 85 that hermetically isolate the front case 1 a and the middle case 1 b are mounted on the rear partition wall 3 that supports the variator shaft 10 and the travel drive input shaft 11 that are mounted with the toroidal transmission mechanism 4. However, an air hole 29 leading to the space between the oil seals 82, 83, 84, 85 is provided to the outside of the case to keep the front case 1a and the middle case 1b airtight by the breather function. . The air hole 29 is connected to the oil seal portion of the PTO transmission shaft 12 and the front wheel drive shaft 13.

  The rotation of the variator shaft 10 drives the planetary gear of the planetary gear mechanism 87 through the gear 26 spline-fitted to the input clutch shaft 25 connected to the variator shaft 10 on the middle case 1b side of the rear partition wall 3 and the one-way clutch 86. Further, the sun gear of the planetary gear mechanism 87 that is directly spline-fitted to the input clutch shaft 25 is also driven. The extension shaft 88 of the travel drive input shaft 11 is spline-fitted with a one-way clutch 27 that meshes with the gear 26 and a gear 89 that meshes with the gear 28 connected to the one-way clutch 86 to transmit power. With such a planetary gear and sun gear drive configuration of the planetary gear mechanism 87, the ring gear is driven to decelerate. Note that the carrier of the gear 28 and the planetary gear mechanism 87 is rotatably supported on the input clutch shaft 25 as one that rotates integrally.

  The rotation of the ring gear is output to the output clutch shaft 92 by rotating the transmission drum 93 by the engagement operation of the multi-plate type low speed clutch 90, and the output clutch shaft 92 is rotated from the low speed reverse rotation by the inclination of the power roller 24. The speed is changed until passing through zero and rotating at a low speed.

  The transmission drum 93 of the multi-plate type high-speed clutch 91 is spline-fitted to the input clutch shaft 25 that is spline-fitted to the gear 26 at the end of the variator shaft 10, and the shift due to the inclination of the power roller 24 is transmitted. The transmission drum 93 of the high speed side clutch 91 is shifted to a higher speed by taking over the maximum forward rotation speed of the low speed side clutch 90.

  With the above configuration, if the low-speed clutch 90 is connected, the output clutch shaft 92 is shifted from low-speed reverse rotation through zero (stopped state) to low-speed normal rotation, and in order to increase speed by normal rotation, The inclination of the power roller 24 is changed by disconnecting the clutch 90 and connecting the high speed side clutch 91. The intermittent timing of the low-speed clutch 90 and the high-speed clutch 91 is controlled by a microcomputer, and the speed is smoothly shifted from low-speed reverse rotation to zero (stop state) to high-speed normal rotation.

  The gear 31 that is spline-fitted to the rear end of the output clutch shaft 92 of the high / low switching clutch 30 is engaged with the gear 33 that is spline-fitted to the differential shaft 32 of the rear differential gear 34 to drive the differential shaft 32. The rotation of the differential shaft 32 is transmitted to the left and right rear wheels 35 via the rear differential gear 34.

  The rotation of the differential shaft 32 is transmitted from a gear 37 to a gear 38 that is spline-fitted to a front wheel drive extension shaft 39 via a dual gear 36 that is loosely fitted to the PTO output shaft 41 to drive the front wheel drive extension shaft 39.

  The front wheel drive extension shaft 39 is equipped with a so-called front wheel speed increasing clutch 40 that drives the front wheels at the same speed or increased speed when the tractor turns. Further, the front wheel drive extension shaft 39 is connected to the front wheel drive extension shaft 39 via the relay shaft 42. The shaft 13 is connected to be transmitted.

The transmission from the variator shaft 10 to the front wheel drive shaft 13 can be simplified by providing a transmission gear set on the front side of the high / low switching clutch 30.
If the gear pump for the traction oil is driven from the gear transmission of the front wheel acceleration clutch 40, the gear pump is close to the valve block, the piping is shortened, the oil flow loss is reduced, and the control response is improved. Reliable control can be performed.

  With the above configuration, the rotation of the engine E is transmitted to the toroidal transmission mechanism 4, and the rotation that is changed by the toroidal transmission mechanism 4 is transmitted to the high / low switching clutch 30. When the low-speed side clutch 90 of the high / low switching clutch 30 is connected and the inclination of the power roller 24 of the toroidal transmission mechanism 4 is changed, the output rotation is steplessly shifted from reverse to forward in the low speed range. This speed change is suitable for traveling conditions in which the work vehicle moves forward and backward at a low speed suitable for ground work. Further, when the high-speed side clutch 91 of the high / low switching clutch 30 is connected and the inclination of the power roller 24 of the toroidal transmission mechanism 4 is changed, the output rotation is steplessly increased within the high speed range. This speed change is suitable for traveling conditions in which the work vehicle moves on the road.

The PTO output shaft 41 that drives the ground work machine is transmitted as follows.
Inside the front and rear partition walls 2 and 3, the gear 43 fixed to the traveling drive input shaft 11 pivoted on the lower part of the toroidal transmission mechanism 4 is engaged with the gear 18 fixed to the PTO input shaft 12, and this PTO transmission shaft 12 is engaged. Is transmitted to the PTO output shaft 41 via a PTO shaft transmission mechanism 44 and a PTO clutch 45 provided at the rear portion of the rear partition 3. The rotation of the PTO output shaft 41 is transmitted to the PTO shaft 47 after being shifted to an appropriate rotational speed by the PTO shaft second transmission mechanism 46 provided in the rear case 1c.

  In this way, the traveling drive input shaft 11, the PTO input shaft 12, and the front wheel drive shaft 13 are supported in the front and rear partition walls 2, 3 containing the toroidal speed change mechanism 4, and the gear set is small, so that it accumulates at the bottom. The hydraulic oil is hardly agitated so much that the hydraulic oil is prevented from bubbling as much as possible to reduce the adverse effect on the toroidal transmission mechanism 4. That is, it is possible to reduce the state in which the foamed working oil enters the contact surface of the rotating roller (power roller 24) with respect to the output disks 4a and 4a and the input disks 4b and 4b and the slip increases.

  Further, in the above configuration, the high / low switching clutch 30, the PTO clutch 45, and the front wheel speed increasing clutch 40, which occupy a large volume, are rationally arranged near the inside of the middle case 1b so that the clutches 30, 45 are arranged. , 40, the responsiveness is improved by shortening the supply path of the control hydraulic pressure, the trunk of the transmission case 1 is not thickened (the cross-sectional area is not increased), and the longitudinal length is not lengthened.

  In addition, by disposing the PTO transmission shaft 12 away from the variator (power roller 24), the size of the variator and the degree of design freedom can be increased. In addition, a so-called lever type mechanism using a rotary arm can be used as an angle change operation linkage mechanism from the hydraulic cylinder to change the angle of the power roller 24 to the power roller 24, and a hydraulic circuit to the hydraulic cylinder can be used. Simplification and reduction of manufacturing costs can be achieved.

  FIG. 5 is a partially enlarged view showing oil supply passages 48 and 49 to the shaft support cylinder chamber 47 with the variator shaft 10 of the output disk 4a, from the outer periphery to the center of the fixed drum 50 on the main input shaft 14 side. The oil supply path 48 provided in communication with the oil supply path 49 is formed in the output disk receiver 51 toward the outer periphery. By sending the pressure oil to the shaft support cylinder chamber 47 through the oil supply passages 48 and 49, the output disk 4a can be pressed toward the input disk 4b, and the output torque of the toroidal transmission mechanism 4 can be increased. . The oil supply to the shaft support cylinder chamber 47 is performed when the angle of the rotating roller (power roller 24) is changed to the speed increasing side.

  The embodiment of FIG. 6 has a structure that lubricates the inside of the high / low switching clutch 30, and an oil path 54 provided at the center of the planetary reduction shaft 52 on the rear side of the transmission of the toroidal transmission mechanism 4 is provided at the shaft end. The annular groove 56 communicates with the orthogonal hole 55, communicates with the oil path 58 of the bracket 57 from the annular groove 56, and is supplied to each groove 59, 60 provided on the shaft peripheral surface of the clutch shaft 53. The oil is supplied to the disk portion of the high / low switching clutch 30 through the oil holes 61 and 62 of the mounting inner cylinder 63.

  FIG. 7 shows an internal lubrication structure on the planetary speed reduction mechanism 65 side in the above configuration, and the oil that has entered the oil path 54 at the center of the shaft from the supply orthogonal hole 64 provided in the vicinity of the shaft end of the planetary speed reduction shaft 52 is shown in FIG. Are supplied to the planetary gear mechanism 87 from the orthogonal holes 66 and 67 provided in the inner side of the motor and lubricated.

  8 and 9 show a configuration in which a planetary reduction mechanism 65 and a high / low switching clutch 30 are provided coaxially with the variator shaft 10, and an oil hole 69 is provided in the center of the planetary gear support shaft 68 of the planetary reduction mechanism 65. Mission oil that is sunk in the recess 71 of the oil reservoir 70 attached to the case 78 is supplied from the oil hole 69 to the needle bearing 94. Thereby, durability of the needle bearing 94 can be improved.

  Further, when the gears 73, 74, 75, 76, 77 that transmit to the high / low switching clutch 30 are helical gears, a thrust force acts in the axial direction of the input clutch shaft 25, but it is formed in the middle case 1b. The input clutch shaft 25 is supported by the bearing walls 80 and 81 on the supporting walls 72 and 79, so that the thrust force is received and supported by the supporting walls 72 and 79. Thereby, the durability of the thrust bearing can be improved by not acting on the thrust bearing of each part of the carrier of the planetary gear mechanism 87.

It is side sectional drawing of the principal part of the mission case which implemented this invention. It is side sectional drawing of the rear part of the mission case which implemented this invention. It is front sectional drawing of the mission case which implemented this invention. It is a power transmission system diagram in a mission case. It is a partial enlarged side view. It is a partially expanded side sectional view of another embodiment. It is a partially expanded side sectional view of another embodiment. It is a partially expanded side sectional view of another embodiment. It is a partially expanded front sectional view of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mission case 2 Front partition 3 Rear partition 4 Toroidal speed change mechanism 10 Variator shaft 11 Travel drive input shaft 12 PTO transmission shaft 13 Work implement drive shaft

Claims (1)

  The transmission case (1) is divided by the front and rear partition walls (2) and (3), and the toroidal transmission mechanism (4) is assembled to the shaft (10) arranged at the upper position inside the transmission case, and the lower side of the toroidal transmission mechanism (4). A traveling drive input shaft (11) for inputting engine power to the toroidal transmission mechanism (4), a PTO transmission shaft (12), and a front wheel drive shaft (13) are provided, and the toroidal transmission mechanism (4) is not immersed in hydraulic oil. A transmission for a work vehicle, characterized in that it is stored in the front and rear partition walls (2) and (3) of the transmission case (1) in a state.

Images