JP4622508B2 - Toroidal transmission for work vehicle - Google Patents

Description

  The present invention relates to a toroidal transmission device for a work vehicle having 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 has 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 A toroidal speed change transmission device for a work vehicle that performs speed change control of power by adjusting the inclination of the motor is known. This toroidal transmission device for work vehicles efficiently shifts traveling power in a wide speed range, including forward and reverse, by introducing 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, since the one-way clutch needs to be fixed as a non-rotating anchor portion, when the rotary transmission system including the toroidal transmission mechanism is assembled in the cylindrical transmission case, the anchor portion is fixed first. However, in order to fix the anchor portion after the assembly of the rotating system, there is a problem that the configuration is complicated and the assembling property is lowered.
JP 2003-74659 A

  The problem to be solved is to provide a toroidal transmission device for a work vehicle that can fix a one-way clutch and assemble a rotating system without complicating the configuration and lowering the assemblability. .

  The invention according to claim 1 includes a case input shaft (3) that receives power from the traveling system and work system from the rear end of the engine, a PTO transmission shaft (4) that receives power from the case input shaft (3), and a case. A traveling transmission shaft (5) for transmitting input power of the input shaft (3) to the traveling system, a toroidal transmission mechanism (21) for continuously changing speed on the traveling transmission shaft (5), and the case input shaft (3) A boss portion (4a) of a gear (4a) attached to the PTO transmission shaft (4) in a toroidal transmission transmission device for a work vehicle comprising a transmission case (2) having a front end closed by a front lid (2f) penetrating and holding 4b) is provided with a one-way clutch (11) for restricting the reverse operation of the PTO transmission shaft (4), and the anchor member (11a) receiving the counter torque of the one-way clutch (11) is attached to the front lid (2f). Wherein the coupling.

When reverse torque is received from the case input shaft, the reverse torque acting on the one-way clutch receives counter torque from the front lid via the anchor member. In addition, since the one-way clutch is disposed on the PTO transmission shaft, the speed change transmission device can be configured without requiring an increase in the overall length of the traveling transmission shaft. By connecting the anchor member of the one-way clutch with the front lid, it can be assembled by fitting in the axial direction of the PTO transmission shaft. In this state, the PTO transmission shaft and the one-way clutch can be handled integrally around the front lid .

In the invention according to claim 1, since the one-way clutch is provided in the rotation transmission system and the anchor member is connected to the front lid, when the reverse torque is received from the case input shaft, the reverse torque acting on the one-way clutch is the anchor member. By receiving the counter torque from the front lid via the front cover, the reverse rotation operation of the rotation transmission system and the toroidal transmission mechanism is restricted, and the stable operation of the toroidal transmission mechanism is ensured. In this case, since the anchor member of the one-way clutch is connected to the front lid, the case input shaft and the subsequent rotation transmission system and the one-way clutch that are passed through the front lid are integrated with the front lid. Can be easily assembled inside.
Therefore, the toroidal transmission device for a work vehicle can fix the one-way clutch and assemble the rotating system with a simple configuration without causing deterioration in assembling performance.
In addition, since the one-way clutch is disposed on the PTO transmission shaft, the speed change transmission device can be configured without requiring an increase in the overall length of the traveling transmission shaft. By connecting the anchor member of the one-way clutch with the front lid, it can be assembled by fitting in the axial direction of the PTO transmission shaft. In this state, since the PTO transmission shaft and the one-way clutch can be handled integrally around the front lid, it can be easily assembled in the transmission case integrally with the front lid .

(Configuration of applicable work vehicle)
Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a side view of an agricultural tractor showing an example of a work vehicle to which a toroidal transmission device according to the present invention is applied.
The agricultural tractor has an engine c mounted on the front portion of the airframe having a front wheel a and a rear wheel b. The rotational power of the engine e is transmitted to the transmission 1 and is appropriately decelerated by the transmission 1. The power is transmitted to the front wheel a and the rear wheel b, and is also output to the work machine W via the rear PTO shaft p.
For operation by the operator, a monitor m that displays a driving state on the front side of the steering handle h, and operating tools such as a forward / reverse switching lever, an accelerator lever L, a brake pedal, and an accelerator pedal t on the lower side of the steering handle h. In other words, a cockpit q provided at the upper part of the transmission 1 and a shift lever s are arranged beside the cockpit q, and are configured to be automatically shiftable by a control unit (not shown). In addition, a lift arm j is provided at the rear portion of the transmission 1 so as to be pivotable in the vertical direction, and the work machine W is configured to be movable up and down via the lift link k.

(Transmission transmission system)
As shown in FIG. 2, the transmission gear transmission 1 includes a mission case 2, a front case input shaft 3, a PTO transmission shaft 4, a travel transmission shaft 5, and an intermediate PTO intermediate shaft, as shown in FIG. 2. 6. The front wheel output shaft 7 and the like are supported in parallel in the front-rear direction, and necessary transmission mechanisms are respectively configured to shift the received engine power to the traveling system and the working system. The transmission case 2 is made of a casting, and includes a front case 2a, a mid case 2b, and a rear case 2c. The front case 2a is provided with a front lid 2f that closes the front end, and traverses the inside on the rear end side. A partition wall 9 is formed to partition the front and rear sections A and B.

  For the individual components, the case input shaft 3 is pivotally supported by the front lid 2f at the front end of the transmission case 2 and receives engine power. The PTO transmission shaft 4 is provided with a gear 4a that receives power from the case input shaft 3 at the front end portion, and is provided with a one-way clutch 11 for restricting reverse rotation to transmit work machine power, and further penetrates the partition wall 9 to transmit the transmission case 2 It extends to the rear so as to cut through the inside, and is provided with a PTO clutch 12 and the like for working system brakes at the rear end.

  The traveling transmission shaft 5 is provided with a gear 5b that receives rotational power in the same direction from the case input shaft 3 via a counter shaft 8 to be described later, on the front stage side, and a planetary difference that follows the variator 21 by the toroidal transmission mechanism and the rear side of the partition wall 9. A moving part 22, a high / low switching part 23 comprising two HiLo clutches, a drive pinion 24 and the like are provided on the same axis.

  The PTO intermediate shaft 6 includes a switching unit 31 that switches from the middle position of the mission case 2 to the rear end and switches the rotation direction of the PTO intermediate shaft 6 between forward and reverse. The switching unit 31 switches the rotational direction of the power transmitted to the front portion of the PTO intermediate shaft 6 via the PTO clutch 12, and switches and transmits the forward rotation power or the reverse rotation power.

  The front wheel output shaft 7 is provided with a gear 7a for receiving branching power from the rear stage portion of the traveling transmission shaft 5 at the rear end portion, and at the front portion is provided with a front wheel speed increasing clutch 32 for switching speed increase by hydraulic control. Front wheel power is output to the front part of 2.

  The variator 21 provided in the traveling transmission shaft 5 is arranged in the front section A of the mission case 2 with a pump 21a that supplies the dedicated hydraulic oil as a separate arrangement. The variator 21 includes two input disks 41 and 42 arranged in the front-rear direction, an output disk 43 arranged between them, and a confronting surface formed in an annular concave toroidal curved surface. The power rollers 44 are provided at equal intervals.

  The hydraulic system of the transmission 1 is configured to supply hydraulic oil individually by configuring the hydraulic system for each of the sections A and B partitioned forward and backward by a partition wall 9 traversing the transmission case 2. The hydraulic system in the front section A divides the variator 21 in the front stage of the traveling transmission shaft 5 that requires special hydraulic oil, and the hydraulic system in the other section B is the rear stage section of the traveling transmission shaft 5 by general hydraulic oil and Divide other work equipment power transmission equipment.

(Hydraulic control system)
The hydraulic system of the transmission 1 and other mounted devices will be described. As shown in the hydraulic system diagram of FIG. 3, the shafts of the cylinder rods 44s of the hydraulic cylinders 44a and 44b are provided to the power rollers 44a by the pump 21a. Supply exclusive hydraulic fluid from the end. With this hydraulic oil, lubrication and cooling are performed to ensure transmission between the input disks 41 and 42 and the output disk 43.

  The master cylinder 44a is applied to one of the three power rollers 44 on the front side and the rear side of the output disk 43, and the other two are applied to the slave cylinder 44b. In order to control the expansion and contraction operation of these cylinders, electromagnetic proportional pressure reducing valves 61 and 61 for controlling the hydraulic oil from the pump 21a are provided, and a set pressure variable reduction valve that receives hydraulic pressure from the electromagnetic proportional pressure reducing valves 61 and 61 to the pilot piston. 62 and 62 are provided symmetrically in both directions of expansion and contraction, and hydraulic oil is supplied to the master cylinders 44a and 44a via the large-diameter dampers 44d and 44d and the check valves 44c and 44c, respectively, and a small-diameter damper is supplied from the master cylinders 44a and 44a. The slave cylinders 44b are interlocked and controlled via 44e, and the power roller 44 is driven forward and backward to control the transmission inclination angle. The large diameter damper 44d is referred to as a mode 1 damper and prevents hydraulic vibration due to the axial deflection of the travel transmission shaft 5, and the small diameter damper 44e is referred to as a mode 3 damper and prevents hydraulic pipe vibration between pistons.

  Further, by providing a shuttle valve 63 for receiving expansion / contraction control pressure and supplying the high pressure side thereof to the end load of the variator 21, the hydraulic pressure is linked to the operating pressure of the hydraulic cylinders 44a and 44b, and the internal piston for the end load is used. To supply. The shuttle valve 63 ensures the responsiveness by pilot control based on the end load pressure, and prevents the overload pressure as substantially the same pressure as the higher one of the cylinder pressures while rolling the power rollers 44. Adjust pressure. These dedicated hydraulic fluids are circulated only in the front compartment A.

  The hydraulic system using other general hydraulic oil is used for controlling the work system of the PTO transmission shaft 4 such as the range of the rear section B of the transmission case 2, that is, the front wheel acceleration clutch 32 at the rear stage of the traveling transmission shaft 5. Lubricating and hydraulic control of equipment such as the PTO clutch 12 and the brake hydraulic control cylinder 71, working equipment lifting hydraulic cylinder 72, working equipment rolling hydraulic cylinder 73, power steering cylinder 74, and other working actuator pumps The supply is controlled by 70. Further, the high / low switching unit 23 using the HiLo clutch at the rear stage of the travel transmission shaft 5 performs the Hi-Lo switching shift by supplying the control hydraulic pressure from the hydraulic control valves 76 and 76 to the travel output shaft 56 at the subsequent stage.

(One-way clutch)
In the transmission 1 described above, 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 sectional view of FIG. A one-way clutch 11 is provided in the portion 4b. The one-way clutch 11 is mounted in a direction that prevents the reverse rotation of the PTO transmission shaft 4, and the main body of the one-way clutch 11 is connected to the front lid 2f to prevent rotation. For example, an anchor arm 11a that functions as an anchor member is extended from the main body of the one-way clutch 11 in an arm shape, and a stud pin 11p is erected on the inner surface side of the front lid 2f at the tip position, and the stud pin 11p is prevented from coming off. A large-diameter middle step portion 11q is formed, and the anchor arm 11a is fitted and connected so as to hold the step portion on the end side.

  The PTO transmission shaft 4 is connected to the case input shaft 3 by gear mechanisms 3a, 4a, and the PTO transmission shaft 4 is restricted in reverse operation by the one-way clutch 11. 3 can be prevented from rotating in the reverse direction, and reverse input from the traveling transmission shaft 5 to the variator 21 can be prevented. Further, by arranging the one-way clutch 11 on the PTO transmission shaft 4, it is possible to configure the transmission 1 without increasing the overall length of the traveling transmission shaft 5, and to fix the anchor arm 11 a of the one-way clutch 11. By connecting with the stud pin 11p of the front lid 2f, it can be assembled by being fitted in the axial direction of the PTO transmission shaft 4. In this state, since the PTO transmission shaft 4 and the one-way clutch 11 can be handled integrally around the front lid, it can be easily assembled into the transmission case 2 integrally with the front lid 2f.

  Therefore, the toroidal transmission mechanism for a work vehicle can prevent a reverse input to the variator 21 and ensure a stable transmission of the power rollers 44 with a simple configuration without increasing the overall length. In addition, the simple configuration allows the one-way clutch 11 to be fixed and the rotating system to be assembled without causing deterioration in assemblability.

(Rear end support member)
Further, as shown in the enlarged cross-sectional view of FIG. 5, the front lid 2f includes a through support portion 3s that supports the case input shaft 3 and a front end support portion that supports the front end of the counter shaft 8 that includes the intermediate gear 8b. 8s is formed, and a separate rear end support member 2r is attached to the inner surface side of the front lid 2f, and a rear end support portion 3t and a counter for pivotally supporting the rear end side of the case input shaft 3 to the rear end support member 2r. A rear end support portion 8t that pivotally supports the rear end of the shaft 8 is formed. The rear end support member 2r is a bracket commonly called metal, and covers the case input shaft 3 and the counter shaft 8 except for the meshing portion of the gear 5b of the travel transmission shaft 5 as shown in the perspective view of FIG. Form. In addition, an oil passage for lubricating the shaft support portions 3s and 8s and the gear meshing portion is formed in the wall thickness of the front lid 2f, and the oil passage 2u is communicated with the attachment surface 2p of the rear end support member 2r. Similarly to the front lid 2f, the oil passage 2u is formed in the wall thickness so as to lubricate the respective shaft support portions 3t, 8r and the gear meshing portion.

  The case input shaft 3 and the counter shaft 8 are supported at two points stably by being pivotally supported by the front lid 2f and the rear end support member 2r. Further, the meshing portions of the gear 4a and the intermediate gear 8b that receive the power of the respective shaft support portions 3s, 8s, 3t, and 8r and the case input shaft 3 via the oil passage 2u for lubrication between the front lid 2f and the rear end support member 2r. And the lubrication of the meshing part of the gear 5b of the traveling transmission shaft 5 is ensured. Therefore, stable support of the transmission shaft and lubrication of the shaft support portion and the gear meshing portion can be ensured without impairing the assembling property.

  Next, the mid case 2b will be described. As shown in the enlarged cross-sectional view of the main part of FIG. 7, an intermediate wall 2m is formed on the midcase 2b, and a separate PTO support member 2n is attached to the intermediate wall 2m. The PTO support member 2n is a bracket commonly referred to as a metal that holds a shaft support portion 4s that penetrates and supports the PTO transmission shaft 4, and a notch J is formed in a part thereof as shown in the enlarged perspective view of FIG. By this, it can arrange | position close to each other, avoiding the conflict with the height switching part 23 which consists of two clutches Hi and Lo arrange | positioned in the back | latter stage of the driving | running | working transmission shaft 5. FIG.

  The PTO clutch 12 is arranged at the rear stage of the PTO support member 2n, and a notch K for fitting the fixing protrusion 12v is formed in a part of the middle wall 2m as shown in the enlarged perspective view of FIG. By doing so, it is possible to constitute a detent during braking. Further, the shaft supporting portions 5s and 5t that support the rear stage of the high / low switching portion 23 are held on the inner wall 2m, and a notch L is formed in a part thereof, thereby avoiding interference with the PTO clutch 12 and being close to each other. Can be arranged.

  Next, the hydraulic path configuration around the transmission will be described. As shown in a perspective view of the arrangement of the hydraulic control valves around the transmission, as shown in FIG. 10, a valve block 71b for the brake, HiLo clutch, and PTO clutch is provided at the top of the transmission case 2, and a valve block for four-wheel drive is provided at the side. 32b, and a side view and a plan view of the hydraulic path are respectively shown in FIG. 11 and FIG. 12, and an oil path from the main relief to the PTO valve at the top of the case 2 is passed through the case. Supply hydraulic pressure to PTO. The side of the case 2 is supplied from the pump by piping, and the PTO valve after the main relief is piped inside the case 2 as shown in the internal perspective view of FIG. By connecting the oil passage to 12, the oil passage to the PTO clutch 12 can be shortened, contributing to cost reduction and control reliability.

Next, the pump drive mechanism will be described.
As shown in FIG. 14, the pump drive mechanism uses a bevel gear on the PTO gear drive side as shown in FIG. 14, and a collar 81 is provided on the spline portion 4 f of the PTO transmission shaft 4 in order to provide the toroidal oil pump 21 a. Is provided. The collar 81 is disposed behind the drive-side bevel gear 82 a and is driven by a PTO gear via a coupling 83. With this configuration, the pump 21a is close to the variator 21, so that the piping is short, the pump 21a is directly attached to the case 2, and the pump can be cooled, and the collar 81 is attached. Thus, many advantages such as the fact that the drive-side bevel gear 82a can be reliably configured can be obtained.

  Further, the driven bevel gear 82b is fitted and attached by a spline, so that it is prevented from coming off by the lower collar 81 without requiring a special stopping structure, and the bevel gear 82b is pushed upward by the thrust of the rotational drive. The mounting portion of the pump 21a is formed with a triangular groove by a taper 84t in the case 2 and sealed with an O-ring 84s so that the pump 21a is inserted from above. Thus, since the pump 21a is mounted upward on the case 2, it can be sealed with the taper 84t and the O-ring 84s without requiring a special oil seal.

  The pump shaft 85 has a stepped 85t on the side of the bevel gear 82b, a slit 85s on the opposite side, and a center paddle 85h provided on the inside thereof to facilitate shaft machining. The support of the pump shaft 85 protrudes from the case 2 downward from the case 2, and driving is ensured by the double bearings 86b and 86b.

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 gearbox. FIG. 3 is a hydraulic system diagram of the speed change transmission. It is an enlarged view of a one-way clutch part. It is a principal part expanded sectional view of a front lid. It is an expansion perspective view of a rear-end support member. It is a principal part expanded sectional view of a mid case. It is an expansion perspective view of a PTO support member. It is an expansion perspective view of a middle wall. It is a perspective view of the hydraulic control valve arrangement around the transmission. It is a side view of a hydraulic path. It is a top view of a hydraulic path. FIG. 3 is a perspective view of a main part inside a transmission. It is a principal part expanded sectional view of a pump drive mechanism.

DESCRIPTION OF SYMBOLS 1 Transmission gear transmission 2 Transmission case 2a Front case 2f Front cover 2r Rear end support member 3 Case input shaft 3a, 4a Gear mechanism 3t Rear end support part (shaft support part)
3s penetration support (shaft support)
4 PTO transmission shaft 4a gear 4b boss portion 5 traveling transmission shaft 5s shaft support portion 8 counter shaft 8b intermediate gear 8s front end support portion 8t rear end support portion 11 one-way clutch 11a anchor arm (anchor member)
11p Stud pin 11q Middle stage 21 Toroidal speed change mechanism (variator)
21a Pump 22 Planetary differential unit 23 Height switching unit 31 Switching unit

Claims (1)

A case input shaft (3) that receives power from the traveling system and work system from the rear end of the engine, a PTO transmission shaft (4) that receives power from the case input shaft (3), and input power of the case input shaft (3) A traveling transmission shaft (5) for transmitting the vehicle to the traveling system, a toroidal transmission mechanism (21) for continuously changing speed on the traveling transmission shaft (5), and a front lid (2f) penetrating and holding the case input shaft (3). ), A toroidal transmission for a work vehicle comprising a transmission case (2) whose front end is closed by
The boss portion (4b) of the gear (4a) attached to the PTO transmission shaft (4) is provided with a one-way clutch (11) for restricting the reverse operation of the PTO transmission shaft (4). A toroidal transmission for a work vehicle, characterized in that an anchor member (11a) that receives torque is connected to the front lid (2f) .

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