JP4847369B2 - Front wheel power take-out device for work vehicle - Google Patents

Description

  The present invention relates to a working vehicle that can transmit power from an engine to a rear wheel and also to a front wheel, and more particularly, to a front wheel power take-out device that extracts a front wheel driving force from within a transmission case.

  Conventionally, a front wheel power take-out device has been devised that enables the work vehicle to turn smaller than the normal turning diameter by driving the front wheel at a speed higher than the peripheral speed of the rear wheel in conjunction with the steering operation of the front wheel. (See Patent Document 1).

  The speed change operation of the front wheel is performed by selectively engaging a plurality of gears loosely fitted to the front wheel drive shaft with a hydraulic clutch, and the hydraulic pressure for connecting and disconnecting the hydraulic clutch includes a switching valve, the plurality of gears, It is supplied through an oil hole provided in a casing that houses the hydraulic clutch.

  The casing is separate from the transmission case and is provided to close the opening on the bottom of the transmission case. Therefore, the switching valve provided in the transmission case and the oil hole provided in the casing are external piping. The pressure oil is supplied and discharged between the transmission case and the casing via the external pipe.

JP 2000-52799 A

  Supplying hydraulic pressure from the transmission case to the hydraulic clutch through the external pipe increases the number of parts, possibly causing damage to the external pipe due to contact with stones, etc. There is a risk of doing.

  Further, when servicing the front wheel drive shaft and the clutch, the casing is removed from the transmission case, and accordingly, the external piping must be detached from the casing and the transmission case, resulting in deterioration of maintainability.

  Therefore, the present invention eliminates the fear of damage to the external piping or the deterioration of the cleanability by supplying the hydraulic pressure to the clutch for shifting the front wheels regardless of the external piping, and the front wheel power take-out device with excellent maintainability. The purpose is to provide.

According to the first aspect of the present invention, a casing (3) that rotatably supports a front wheel drive shaft (2) having gears (2c, 2d) and a hydraulic clutch (C1, C2) is provided on the bottom surface of the transmission case (5). It attaches so that it may obstruct | occlude in the opening part (6) of this, and it is for said front wheels from the power transmission device (A) in the said transmission case (5) via the said gears (2c, 2d) and a hydraulic clutch (C1, C2). In the front wheel power take-off device (1) in the working vehicle, which transmits power to the drive shaft (2),
The transmission case (5) is provided with a switching valve (4) for switching the hydraulic clutch (C1, C2),
The hydraulic chamber (12, 13) of the hydraulic clutch (C1, C2) and the switching valve (4) communicate with the transmission case (5), the casing (3), and the front wheel drive shaft (2). made by forming bonding surfaces on each other physician (7, 8a, 8b) oil hole connecting with (2a, 2b, 3a, 3b , 5a, 5b) respectively so as,
The present invention provides a front wheel power take-out device for a working vehicle.

According to a second aspect of the present invention, the gears (2c, 2d) and the hydraulic clutch (C1, C2) are a standard gear (2d) and a hydraulic clutch for transmitting rotation to the front wheels at a rotational speed substantially the same as that of the rear wheels. (C1), and a quick turn gear (2c) and a hydraulic clutch (C2) for transmitting rotation to the front wheels, which has a faster peripheral speed than the rear wheels,
The switching valve (4) communicates with the standard hydraulic clutch (C1) and the quick turn hydraulic clutch (C2) through different oil holes (2a, 2b, 3a, 3b, 5a, 5b). Become,
A front wheel power take-out device for a working vehicle according to claim 1.

  According to the first aspect of the present invention, although the front wheel power take-out device is provided in a casing separate from the transmission case, the transmission valve is connected to the transmission case, the casing, and the front wheel drive shaft. Since each oil hole communicating with the hydraulic clutch is formed, there is no need for external piping such as pipes, it can be configured at low cost, the appearance can be neatly organized, and the external piping can be damaged and become inoperable. Can be prevented.

  Also, the maintenance of the front wheel power take-out device such as a hydraulic clutch can be easily performed by removing the casing from the transmission case, and the maintainability can be improved as compared with the one that requires detachment of external piping. .

  According to the second aspect of the present invention, the front wheel power take-out device includes a hydraulic clutch that turns on and off the power for quick turn in addition to the hydraulic clutch that turns on and off the power for standard rotation. The piping is complicated, but even in this case, the oil holes for both hydraulic clutches can be formed in the transmission case, casing, and front wheel drive shaft, respectively, and the above-described effects can be surely produced. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross section of a power transmission device A for a working vehicle according to the present embodiment.

  In FIG. 1, reference numeral 20 denotes a main transmission that transmits power from an engine via an output gear 21 a provided on an output shaft 21, and between the main transmission 20 and the forward / reverse switching device 40. A main clutch 30 for connecting / disconnecting power transmission from the engine is disposed. An auxiliary transmission 50 is disposed adjacent to the forward / reverse switching device 40 to transmit power to the rear wheel axle 57. On the other hand, power is transmitted to the front wheels by the front wheel power take-out device 1 provided in the casing 3 that closes the opening opened at the bottom of the transmission case 5.

  The main transmission 20 includes a main shaft 22 provided with a transmission gear 22a meshing with the output gear 21a at the front end, and a transmission shaft 23 provided in parallel with the main shaft 22 in the axial direction on the inner diameter side.

  The main shaft 22 is provided with four gears 22b, 22c, 22d, and 22e on the main transmission drive side having different transmission ratios, and four main transmission driven gears 23a, on the transmission shaft 23 having different transmission ratios. It meshes with 23b, 23c, and 23d. Between the driven gears (between the gears 23a and 23b, between the gears 23c and 23d), always-mesh (synchromesh type) shift members 24 and 25 are interposed. ing. By the shift members 24 and 25, one of the four driven gears 23a, 23b, 23c and 23d is selectively linked.

  A main clutch 30 is provided between the main transmission 20 and the forward / reverse switching device 40, and a clutch hub at the rear end of the transmission shaft 23 and a clutch at the front end of the interlocking shaft 41 of the forward / reverse switching device 40 described later. The friction member provided on the drum is engaged with the piston to connect and disconnect the power from the engine.

  The forward / reverse switching device 40 adjacent to the main clutch 30 includes an interlocking shaft 41 provided coaxially with the transmission shaft 23, a reverse idle shaft 42 provided axially parallel to the interlocking shaft 41 on the inner diameter side, On the radial side, it has an interlocking shaft 41 and a forward / backward moving shaft 43 provided parallel to the axial direction.

  The interlocking shaft 41 is provided with gears 41a and 41b. The gear 41a meshes with a reverse transmission gear 42a fitted into the reverse idle shaft 42, and the reverse transmission gear 42a is a forward / reverse shaft. The reverse gear 43a is engaged with the reverse gear 43a. Further, the gear 41 b of the interlocking shaft 41 meshes with a forward gear 43 b that is fitted on the forward-reverse shaft 43.

  A shift member 44 is interposed between the forward gear 43b and the reverse gear 43a, and only one of the forward gear 43b and the reverse gear 43a is selectively linked. The

  A subtransmission device 50 is provided behind the forward / reverse switching device 40. The subtransmission shaft 51 is arranged coaxially and rearward with the forward / reverse shaft 43, and the subtransmission shaft 51 and the axial direction on the inner diameter side. A transmission shaft 52 provided in parallel and an interlocking shaft 53 connected to the rear end of the transmission shaft 52 are provided.

  The auxiliary transmission shaft 51 is provided with auxiliary transmission gears 51a and 51b, and a shift member 56 is interposed between the auxiliary transmission gears 51a and 51b. The sub transmission gears 51a and 51b mesh with the gears 52a and 52b fitted on the transmission shaft 52, and either one of the sub transmission gears 51a and 51b is selectively engaged with the gears 52a and 52b by the shift member 56. Combined.

  The gears 53a and 53b provided on the interlocking shaft 53 are an ultra-low speed gear sleeve 61a rotatably fitted on a switching shaft 54 disposed on the outer diameter side in parallel with the interlocking shaft 53 and a bearing. Is provided so as to mesh with a gear 54c rotatably provided on the switching shaft 54.

  In addition to the ultra-low speed gear sleeve 61a and gear 54c of the ultra-low speed gear unit 60, the switching shaft 54 includes a front wheel drive gear 54b, a quick-turn gear sleeve 54a, and a quick-turn gear fixed to the switching shaft 54. A small-diameter switching shaft driving gear 54d provided integrally with the sleeve 54a is provided.

  A final shaft 55 provided on the outer diameter side in parallel with the switching shaft 54 is provided with an ultra-low speed gear 61b, a rear wheel drive gear 55a, and a transmission gear 55b. A shift member 57 is interposed between the ultra-low speed gear 61b and the rear wheel drive gear 55a, and the rear wheel drive gear 55a or the ultra-low speed gear 61b is selectively interlocked, Power is transmitted to the rear wheel drive shaft 58 via the bevel gear 56. Further, when the shift member 57 is in the neutral position, the gears 55 a and 61 b are idle with respect to the final shaft 55. The transmission gear 55 b meshes with the switching shaft drive gear 54 d of the switching shaft 54, and rotates the switching shaft 54 in conjunction with the final shaft 55.

  On the other hand, the front wheel power take-out device 1 has a front wheel drive shaft 2 that extends forward in parallel with the switching shaft 54 on the inner diameter side. The front-wheel drive shaft 2 is supported by a boss 3c and a sleeve 3d, and a quick-turn gear 2c that meshes with front-wheel power take-out gears 54a and 54b, and a standard gear (standard gear) that is normally linked. ) 2d is provided on the front wheel drive shaft 2 via a first clutch (standard hydraulic clutch) C1 and a second clutch (quick turn hydraulic clutch) C2.

  As shown in FIGS. 2, 3 and 4, the front wheel power take-out device 1 includes a casing 3 including the first and second clutches C1 and C2 and the front wheel drive shaft 2 as a unit, In order to fix the casing 3 so as to close the opening 6 on the bottom surface of the transmission case 5, the casing mounting surfaces (joint surfaces) 8a and 8b are joined by bolts. Further, a switching valve 4 is mounted on a switching valve mounting surface (joint surface) 7 on the bottom side surface of the transmission case 5 to control the hydraulic pressure supply to the first clutch C1 and the second clutch C2.

  The switching valve mounting surface 7 is provided with two different oil holes 5a and 5b for pressure oil supplied from the switching valve 4 to the first and second clutches C1 and C2. The oil holes 5a and 5b are configured to pass through the transmission case 5 and open at the casing mounting surface 8a and to be connected to the oil holes 3a and 3b provided on the casing-side mounting surface 8b.

  As shown in FIG. 5, two different oil holes 3 a and 3 b pass through the casing 3 and communicate with two different oil holes 2 a and 2 b provided in the front wheel drive shaft 2 housed in the transmission case 5. . The oil hole 2 a is connected to the hydraulic chamber 12 of the first clutch C 1 through the oil hole a provided in the clutch cylinder 11, and the oil hole 2 b passes through the oil hole b provided in the clutch cylinder 11. It is connected to the hydraulic chamber 13 of the two-clutch C2.

  The hydraulic chamber 12 of the first clutch C <b> 1 includes a piston 14, a clutch cylinder 11, and a cancel plate 15, and a spring 16 is provided between the back side of the piston 14 and the clutch cylinder 11. The spring 16 urges the piston 17 so that friction members provided on the drum portion of the clutch cylinder 11 and the hub portion of the standard gear 2d are engaged.

  The hydraulic oil chamber 12 of the second clutch C2 includes a piston 17 and a clutch cylinder 11, and a return spring 18 is provided on the opposite side of the hydraulic oil chamber 12. The return spring 18 urges the piston 17 so that the friction members provided on the drum portion of the clutch cylinder 11 and the hub portion of the quick turn gear 2c are separated from each other.

  As shown in FIG. 6, the front wheel power take-out device 1 is divided into a first clutch C1 that functions as a four-wheel switching device and a second clutch C2 that functions as a quick turn device via two different oil passages for the oil pressure from the oil pump P. Supply through filter F. The two different oil passages are provided with electromagnetic switching valves 4a and 4b to control the supply and discharge of the pressure oil to the first clutch C1 and the second clutch C2.

  The first clutch C1 is configured to be disconnected when the pressure oil is supplied by the electromagnetic switching valve 4a, and the second clutch C2 is engaged when the pressure oil is supplied by the electromagnetic switching valve 4b. It is configured. Due to the connection and disconnection of the first and second clutches, the work vehicle has a three-wheel drive state in which the peripheral speed of the front wheels and the peripheral speed of the rear wheels are substantially equal, a quick turn state in which a small turn is possible, and a two-wheel drive state. One traveling state can be selected as appropriate.

  The operation of the front wheel power take-out device according to the present embodiment will be described below.

  When the working vehicle is driven in a normal four-wheel drive state, both the electromagnetic switching valves 4a and 4b are disconnected, and the hydraulic pressures in the hydraulic chambers 12 and 13 of the first clutch C1 and the second clutch C2 are discharged, so that the first clutch Engage only C1.

  When the first clutch C1 is engaged by the urging force of the spring 16, the power from the engine is transmitted to the front wheel drive shaft 2 by the standard gear 2d that meshes with the front wheel drive gear 54b, and the front wheels and the rear wheels are substantially the same. Drive at peripheral speed.

  When the working vehicle tries to turn slightly while the vehicle is running in a four-wheel drive state, the steering operation of the front wheels is detected, and the hydraulic pressure from the oil pump P is changed by the electromagnetic switching valves 4a and 4b to the first clutch C1 and the second clutch. It is supplied to the hydraulic chambers 12 and 13 of the clutch C2, the first clutch C1 is disconnected, and the second clutch C2 is engaged.

  The oil pressure from the oil pump P is supplied to the first clutch C1 through an oil hole 5a provided in the transmission case 5, an oil hole 3a provided in the casing 3, and an oil hole 2a provided in the front wheel drive shaft 2. The oil hole a is supplied to the hydraulic chamber 12 of the first clutch C1, and the second clutch C2 includes an oil hole 5b provided in the transmission case 5, an oil hole 3b provided in the casing 3, and a front wheel drive shaft 2. The oil hole b is supplied to the hydraulic chamber 13 of the second clutch C2 through the provided oil hole 2b.

  When the second clutch C2 is engaged, the power from the engine is transmitted to the front wheel drive shaft 2 by the quick turn gear 2c meshing with the quick turn gear sleeve 54a, and the front wheels are driven faster than the peripheral speed of the rear wheels. Make a small turn.

  When the hydraulic pressure from the oil pump P is supplied only to the hydraulic chamber 12 of the first clutch C1 by the electromagnetic switching valve 4a, both the first clutch C1 and the second clutch C2 are disconnected, and the power from the engine is transmitted to the front wheels. The two-wheel drive state is entered without being transmitted.

  As described above, by supplying hydraulic pressure to the first clutch C1 that is a standard hydraulic clutch and the second clutch C2 that is a quick-turn hydraulic clutch regardless of external piping, the front wheel power take-out device 1 can be configured at low cost. The appearance can be clearly organized, and the external piping can be prevented from being damaged and inoperable.

  Furthermore, when the front wheel power take-out device 1 such as the first and second hydraulic clutches C1 and C2 is maintained, it is not necessary to attach or detach external piping, and it can be easily performed by removing the casing 3 from the transmission case 5. Therefore, maintainability is improved.

Sectional drawing of the power transmission device which concerns on this invention. 1 is a perspective view of a front wheel power take-out device according to the present invention. The perspective view of the front-wheel motive power taking-out apparatus from the body bottom face. The perspective view of the front-wheel power take-out apparatus from the body bottom left side. The principal part expanded sectional view of a front-wheel power take-out apparatus. The hydraulic circuit diagram of a front wheel power take-out device.

Explanation of symbols

2a Oil hole 2b Oil hole 2c Quick turn gear 2d Standard gear 3 Casing 3a Oil hole 3b Oil hole 4 Switching valve 5 Mission case 5a Oil hole 5b Oil hole 7 Joint surface 8a Joint surface 8b Joint surface C1 Standard hydraulic clutch ( (First clutch)
C2 Quick turn hydraulic clutch (second clutch)

Claims (2)

A casing for rotatably supporting a front wheel drive shaft having a gear and a hydraulic clutch is attached so as to be closed at the opening of the bottom surface of the transmission case, and the power transmission device in the transmission case is connected via the gear and the hydraulic clutch. In the front wheel power take-off device in the working vehicle, wherein the power is transmitted to the front wheel drive shaft.
The transmission case is provided with a switching valve for switching the hydraulic clutch,
The transmission case, the casing and the front-wheel drive shaft, obtained by forming respective oil holes connecting the cemented surface and the hydraulic chamber of the hydraulic clutch said control valve to each other physician so as to communicate,
A front wheel power take-out device for a working vehicle. The gear and the hydraulic clutch transmit to the front wheels the standard gear and the hydraulic clutch that transmit rotation to the front wheels, which is substantially the same peripheral speed as the rear wheels, and rotation that has a higher peripheral speed than the rear wheels. Quick turn gear and hydraulic clutch,
The switching valve communicates with the standard hydraulic clutch and the quick turn hydraulic clutch through the different oil holes, respectively.
The front wheel power take-out device in the working vehicle according to claim 1.

Images