JP4301062B2 - Work vehicle having toroidal transmission - Google Patents

Description

  The present invention relates to a work vehicle including a toroidal transmission in a transmission case.

  As shown in Patent Document 1, a power roller that is applied to a work vehicle such as a tractor and includes a transmission mechanism using a full toroidal variator in which an input and an output disk are arranged to face each other and is interposed between input and output disks. 2. Description of the Related Art There is known a work vehicle transmission that shifts power by adjusting the inclination of the vehicle. This work vehicle transmission system efficiently shifts and outputs a wide range of traveling power including forward and reverse rotation by guiding the shifting power extracted from the output disk of the toroidal transmission mechanism to the planetary gear mechanism on the intermediate transmission shaft. Can do.

On the other hand, the toroidal speed change mechanism has a problem that when the reverse rotation operation due to the swing back when the engine is stopped or the like is input to the variator, the power roller sometimes comes off between the input and output disks. In order to solve this, it is necessary to provide a one-way clutch in order to prevent reverse rotation input to the variator. However, if a one-way clutch is provided on the input shaft of the variator, the overall length of the transmission increases, and when the work vehicle is configured by mounting this, the wheel base size of the fuselage is increased.
JP 2003-74659 A

  The problem to be solved is to provide a work vehicle having a toroidal transmission that can prevent the engagement and disengagement of the power roller of the variator with a simple configuration without increasing the total length of the transmission.

The invention according to claim 1 is provided with a hydraulic cylinder for raising and lowering the work implement at the rear part of the transmission case having a case input shaft that receives power from the engine, and there is no input power of the case input shaft by driving a power roller in the case. In a working vehicle that includes a variator mechanism that performs step shifting and a toroidal transmission mechanism that includes a HiLo clutch that switches transmission torque of the shifting power between high and low levels, and that splits the input power of the case input shaft and transmits it to the PTO shaft. In the transmission case, there are provided a PTO transmission shaft for transmitting branch power from the case input shaft to the PTO shaft through a meshing gear at all times, and a traveling transmission shaft for supporting the variator mechanism, and from the gear on the PTO transmission shaft. a position close to the gear range leading to the PTO forward-reverse switching clutch, the one-way rotation A one-way clutch to allow the formed,
The variator is composed of at least two front and rear input disks, an output disk disposed between them, and a power roller, and a drum is provided on the back of the input disk.
A preloading disc spring and its holding collar are attached to the back of the drum, and the input gear of the traveling transmission shaft is placed in contact with this collar, and a lock nut is attached to the traveling transmission shaft so as to hold down this input gear. It is characterized by providing .

With the above configuration, the engine power is branched from the case input shaft to the PTO transmission shaft and the traveling transmission shaft, and transmitted to the PTO shaft and the toroidal transmission mechanism, respectively. In this case, when the case input shaft is swung back from the engine, the reverse rotation of the case input shaft is restricted by the one-way clutch on the PTO transmission shaft.
Further, by arranging the one-way clutch on the PTO transmission shaft, it is possible to configure the transmission without requiring an increase in the total length of the traveling transmission shaft.

The effect of the invention according to claim 1 is that the transmission can regulate the reverse rotation of the case input shaft by a simple configuration with a one-way clutch attached to the gap position on the PTO transmission shaft extending to the rear stage of the case. Therefore, without causing an increase in the overall length of the transmission, it is possible to prevent the power roller from popping out by preventing reverse rotation input to the variator mechanism and to ensure a stable speed change operation.
Further, since the disc spring can be pressed by the input gear and the collar in contact with the lock nut and the drum can be preloaded, the number of parts can be reduced and the preload portion of the disk can be configured compactly.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side view of an agricultural tractor showing an example of a work vehicle according to the present invention. The agricultural tractor has an engine c mounted on the front part of the machine body including a front wheel a and a rear wheel b, transmits the rotational power of the engine c to the transmission 1, and the power appropriately decelerated by the transmission 1 is transmitted to the front wheel. It transmits to a and the rear wheel b, and it is comprised so that it may output to the working machine K1 via the PTO shaft k of the rear part. The work machine K1 is connected to the rear part of the machine body via a three-point link mechanism R so that the work machine K1 can be moved up and down by a work machine lifting hydraulic cylinder Y. For operation by the operator, a monitor m for displaying the driving state on the front side of the steering wheel h, a forward / reverse switching lever n and an accelerator lever L for switching forward and backward, a brake pedal t1 and an accelerator pedal p at the base, A shift lever 7 and the like are arranged on the side of the cockpit q provided in the upper part of the mission case 2, and are configured to be automatically shiftable by a control unit (not shown).

FIG. 2 is a cross-sectional view of the main part of the transmission 1 as developed by the axis.
In FIG. 2, the transmission 1 supports a case input shaft 3, a PTO transmission shaft 4, a traveling transmission shaft 5, and the like at a front stage position of a transmission case in parallel in the front-rear direction. The case input shaft 3 is supported by the front end portion of the transmission case 2 and receives the power of the engine c. The PTO transmission shaft 4 receives the branching power from the case input shaft 3 and extends to the subsequent stage, and transmits it to a PTO forward / reverse switching clutch (not shown) for work system transmission control. The travel transmission shaft 5 includes a variator 21 that continuously changes the power received from the case input shaft 3 by means of input / output disks 41, 42, 43 and a power roller 44, a differential unit 22 by a planetary mechanism that follows the variator 21, and the like. A full toroidal transmission mechanism is provided on the same axis so as to be transmitted to the traveling system.

  In the transmission 1, the front end portion of the PTO transmission shaft 4 receives power from the case input shaft 3 via the gear mechanisms 3a and 4a, as shown in the enlarged view of FIG. A one-way clutch 11 is provided at a position close to the gear 4a within a range reaching the switching clutch. The one-way clutch 11 is supported by a holder 12 in such a direction as to prevent reverse rotation of the PTO transmission shaft 4, and this holder 12 is formed on the inner peripheral surface of the transmission case 2 as shown in the perspective front view of FIG. Fastened to the mounting seat 13 to form a detent. Further, the rotational power is transmitted from the shaft end of the case input shaft 3 to the front side of the traveling transmission shaft 5 through the gear mechanisms 3b, 6b, 5b by the intermediate shaft P6.

  As described above, the PTO transmission shaft 4 is connected to the case input shaft 3 by the gear mechanisms 3a and 4a, and the reverse rotation operation of the PTO transmission shaft 4 is restricted by the one-way clutch 11. The reverse rotation of the input shaft 3 can be prevented, and the reverse rotation input from the travel transmission shaft 5 to the variator 21 can be prevented. Further, by arranging the one-way clutch 11 on the PTO transmission shaft 4, the transmission 1 can be configured without requiring an increase in the overall length of the traveling transmission shaft 5. Therefore, with a simple configuration within the range of the overall length of the transmission 1, the reverse rotation input to the variator 21 can be prevented, and stable transmission of the power rollers 44 can be ensured.

Next, the variator 21 will be described.
As shown in the enlarged view of FIG. 5, the variator 21 configured on the traveling transmission shaft 5 includes two input disks 41 and 42 arranged in the front-rear direction, an output disk 43 arranged between them, and an annular surface between each other. It is composed of six power rollers 44, etc., which are formed in a concave shape and are interposed between these opposing surfaces at an equally divided interval of 120 °. A drum 46 is provided on the rear surface of the input disk 41, and hydraulic pressure is introduced to ensure the transmission of the power rollers 44 by an end load.

  The power rollers 44 are respectively provided with forward and backward drive cylinders 44c, and are arranged with the axes of two adjacent cylinders 44c and 44c parallel to each other and tilted toward the rear stage of the transmission case 2. These power rollers 44 ... have many advantages in terms of not only easy machining of the cylinder, but also a hydraulic stop end, and the commonality of parts by arranging the cylinder axis lines at the same angle. It is what you have.

  An outer peripheral member 47 is attached to the output disk 43 by press fitting. The outer peripheral member 47 is formed in a fence shape so as to surround the outer periphery of the rolling surfaces S, S of the power roller 44, and rotation detection grooves 47a are formed at equal intervals on the entire circumference. In general, since fence processing cannot be performed in the outer direction of the output disk 43, it is not possible to prevent the power rollers 44 from popping out, and if the rotation detection grooves 47a are directly processed into the disk 43, the strength is reduced. However, the outer peripheral member 47 can prevent the power rollers 44 from popping out due to a sudden load fluctuation state, thereby ensuring fail-safety. In addition, the press-fitting of the outer peripheral member 47 can maximize the stress distortion without causing a decrease in the strength of the disk 43, and the rotation detection groove 47a can reliably rotate the output disk 43. Since it can be detected, complete control is possible.

  A preload disc spring 48 and a presser collar 48a are attached to the rear surface of the drum 46, and an input gear 5b of the travel transmission shaft 5 is disposed in contact with the collar 48a so as to press the input gear 5b. A lock nut 49 is provided on the traveling transmission shaft 5. With this configuration, the disc spring 48 can be pressed by the input gear 5b and the collar 48a in contact with the lock nut 49, and the drum 46 can be preloaded. Can be configured.

  As shown in the enlarged view of FIG. 6, the latter stage of the variator 21 includes sleeve-like transmission members 45, 45 a, 45 b that extend rearward from the output disk 43 around the traveling transmission shaft 5, and further, the traveling transmission shaft. The sleeve portion 51a of the shaft end member 51 integrally attached to the rear end portion of the shaft 5 is concentrically configured, and the sleeve of the shaft end member 51 is lubricated to lubricate the shaft support portion by a needle bearing or the like interposed therebetween. Ports 51p, 45p, and 5p are formed transversely in each member so as to penetrate from the portion 51a to the central oil passage 5c of the traveling transmission shaft 5. By forming the lubricating oil path in this manner, the lubricating oil can be sufficiently supplied to the needle 43r of the output disk having the highest rotational speed, so that the durability can be improved.

  As shown in the system diagram of FIG. 7, the lubrication system of the transmission can secure a traction oil film and prevent seizure by connecting a forced oil supply path B to the power rollers 44. Further, by controlling the control pressure of the working cylinders 44c of the power rollers 44 individually via the two proportional pressure control valves V and V, fine position (pressure) control of the power rollers is possible.

It is a side view of the work vehicle of this invention. It is principal part sectional drawing by the axial line expansion | deployment of a transmission. It is an enlarged view of a case input shaft part. It is a see-through | perspective front view of a transmission. It is an enlarged view of a variator. It is an enlarged view of the rear stage part of a variator. It is a hydraulic system figure of a transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission device 2 Transmission case 3a, 4a Gear mechanism 3b, 5b, 6b Gear mechanism 3 Case input shaft 4 PTO transmission shaft 5 Traveling transmission shaft 11 One-way clutch 12 Holder 13 Mounting seat 21 Variator mechanism 22 Differential part 41, 42 Input disk 43 Output disk 44 Power roller 47 Outer peripheral member 47a Groove c Engine K PTO shaft

Claims (1)

A hydraulic cylinder (Y) for raising and lowering the work implement is provided at the rear of the transmission case (2) having a case input shaft (3) for receiving power from the engine, and the power rollers (44, 44...) Are provided in the case (2). A variator mechanism (21) for continuously changing the input power of the case input shaft (3) by driving and a toroidal transmission mechanism having a HiLo clutch (23) for switching the transmission torque of the speed change power between high and low levels, and a case In a work vehicle that branches input power of the input shaft (3) and transmits it to the PTO shaft (K),
In the transmission case (2), PTO transmission for transmitting branching power from the case input shaft (3) to the PTO shaft (K) through the constant meshing gears (3a, 4a) (3b, 6b, 5b). A travel transmission shaft (5) that supports the shaft (4) and the variator mechanism (21) is provided,
A one-way clutch (11) that allows only one-way rotation is provided at a position close to the gear (4a) in a range from the gear (4a ) on the PTO transmission shaft (4) to the PTO forward / reverse switching clutch ,
The variator (21) is composed of at least two front and rear input disks (41, 42), an output disk (43) disposed between them, and a power roller (44). A drum (46) is provided on the back,
A preload disc spring (48) and a presser collar (48a) are attached to the rear surface of the drum (46), and the input gear (5b) of the travel transmission shaft (5) is in contact with the collar (48a). And a lock nut (49) is provided on the travel transmission shaft (5) so as to hold down the input gear (5b) .

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