JP2005114064A - Transmission case construction of work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission case construction of a work machine capable of surely supplying a lubricating oil to the upper part in the case, with a low-cost configuration. <P>SOLUTION: An oblong transmission case 15 in which transmission gears are housed by pivoting has a split construction, two halves, where split case parts 15f and 15r are jointed. A groove 75 is formed on at least one of the joint surfaces of the split case parts 15f and 15r. An oil path e for supplying a lubricating oil to the upper part of the case is formed between the joint surfaces of the split case parts 15f and 15r that are jointed together. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a transmission case provided in a working machine such as a riding mower or an agricultural tractor.

  Lubricating oil stored in the transmission case of the work equipment is often set so that the oil level is located at about the middle of the case height in order to reduce weight and avoid spout. Lubricating oil is not sufficiently supplied to the gears and bearings that are located.

In work machines, the lubricating oil stored in the transmission case is often used as hydraulic fluid for hydraulic equipment. In agricultural tractors, the control valve of the hydraulic equipment is installed at the upper end of the transmission case to transmit the return oil. A structure is employed in which lubricating oil can be supplied to a gear or the like located in the upper part of the case by reducing the gas directly to the case (see, for example, Patent Document 1).
JP 2000-92912 A, paragraph (0035) 4-6 lines, FIG.

  However, in the structure in which the control valve of the hydraulic device is not provided at the upper end portion of the transmission case, in order to supply the lubricating oil to the lubrication-necessary position located in the upper part of the case, (a) return oil of the hydraulic device is used. Means for supplying to the upper part of the case using an external pipe, (b) Means for forming an oil passage in the vertical wall of the transmission case, or case where the stored lubricating oil is flipped up using the rotation of the gear Although the means for supplying to the upper part of the inside is adopted, the means (a) and (b) increase the cost, and the means (c) lacks the reliability of the lubricating oil supply. was there.

  The present invention has been made paying attention to such points, and provides a transmission case structure for a work machine that can reliably supply lubricating oil to the upper portion of the case with an inexpensive configuration. The main purpose.

  According to a first aspect of the present invention, there is provided a transmission case structure for a work machine, wherein a vertically long transmission case that pivotally accommodates a transmission gear group is formed into a two-part structure in which divided case portions are joined and connected. A groove is formed in at least one, and an oil passage for supplying lubricating oil to the upper part of the case is formed between the joint surfaces of the divided and joined case parts.

  According to this configuration, the oil passage forming groove formed on the joint surface of the split case portion can be integrally formed between any upper and lower positions when the split case portion is molded, and the lower portion of the groove is lubricated. By supplying the oil, it becomes possible to forcibly supply the lubricating oil to the upper part of the case.

  Therefore, according to the present invention, it is possible to carry out easily and inexpensively without requiring drilling for forming an oil passage and without using an external pipe for oil passage construction. Lubricating oil can now be reliably supplied to places where lubrication is required.

The transmission case structure of the work machine according to the second invention is the first invention,
An output from the hydraulic continuously variable transmission is configured to be input to the transmission case, and surplus oil of charge oil supplied to the hydraulic continuously variable transmission is configured to be guided to a lower portion of the oil passage. It is characterized by.

  According to this configuration, it is possible to reliably supply the lubricating oil to the lubrication required part on the upper part of the transmission case by using the configuration in which the charge oil is forcibly supplied to the hydraulic continuously variable transmission. Therefore, the above-described effect of the first invention can be promoted.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an entire side surface of a riding mower as an example of a working machine according to the present invention, and FIG. 2 shows an entire plane thereof. This riding mower has a structure in which a mower 4 is suspended and supported so as to be freely driven up and down between front and rear wheels of a riding traveling machine body 3 having a pair of left and right front wheels 1 made of caster wheels and a rear wheel 2 that is independently driven left and right. An engine 5 is mounted on the rearmost portion of the passenger traveling aircraft 1, and a driver seat 6 is provided at a front and rear intermediate portion on the aircraft.

  Further, a gate-shaped support column 7 erected on the rear part of the driver's seat 6 is equipped with a grass collection container 10 via a link mechanism 9 having a parallel quadruple link structure that is driven up and down by a hydraulic cylinder 8. This grass collection container 10 is configured not only to be moved up and down largely in parallel via the link mechanism 9, but also configured to be open dumped around the fulcrum a by the dump silin 11 at an arbitrary height position. In the lowered position, the grass collection container 10 is connected to the duct 12 extending rearward from the mower 4 through the lower abdomen of the fuselage.

  FIG. 2 schematically shows a transmission system for driving the rear wheel 3 and the mower 4.

  The engine 5 uses a water-cooled engine that outputs toward the front, and the output is transmitted to the input shaft 16 of a vertically long transmission case 15 disposed in front of the engine via a constant velocity joint 17. After the power transmitted to the input shaft 16 is transmitted to the third shaft 19 through the second shaft 18, the power is branched to the traveling system and the working system on the third shaft 19.

  The power of the traveling system is branched from the rear portion of the third shaft 19 and is transmitted to the lateral input shaft 21 of the hydraulic continuously variable transmission (HST) 20 connected to the left and right of the transmission case 15 via the bevel gear mechanism 22. A speed reduction case 23 extends downward and is connected to the lateral outer surface of each hydraulic continuously variable transmission 20, and the speed change power extracted from the output shaft 24 of the hydraulic continuously variable transmission 20 is within the speed reduction case 23. The gear is decelerated and transmitted to the rear axle 25 provided at the lower part of the case.

  Here, the well-known axial plunger type is adopted as the hydraulic continuously variable transmission 20, and the motor M is steplessly changed by changing the discharge oil amount and the discharge direction by changing the swash plate angle of the pump P. It is configured to shift forward and reverse. A swash plate angle operation shaft (not shown) and a travel lever 25 arranged to be able to swing back and forth in front and right of the driver's seat 6 are interlocked and connected, and there is no need to hold the travel lever 25 in the front-rear neutral position. The step transmission 20 is stopped, and a stepless forward shift can be performed by operating the traveling lever 25 forward from the neutral position, and a stepless reverse shift can be performed by operating backward.

  The output shaft 24 of each of the left and right hydraulic continuously variable transmissions 20 extends into the transmission case 15 and is butt-deployed, and a multi-plate brake 26 is provided on the inwardly extending portion 24a of each output shaft 24. Each is provided. As shown in FIG. 8, the brake 26 is configured to perform braking by shifting the pressing plate 27 by rotating the common rotating cam plate 28, and rotates the rotating cam 28. The brake operation shaft 29 and a brake pedal 30 provided at the foot in front of the driver's seat are linked to each other, and when the brake pedal 30 is depressed, the left and right brakes 26 are simultaneously braked. Although not shown, a brake lock pedal for parking is provided on the lateral side of the brake pedal 30 to step on the brake pedal 30 and hold it at the braking position.

  The power of the work system is branched from the front portion of the third shaft 19, transmitted to the fourth shaft 36 via the PTO clutch 35, and then transmitted to the output shaft 38 below the case via the fifth shaft 37. Then, it is taken out to the lower front of the transmission case 15. The power extracted from the output shaft 38 is input to the PTO case 40 at the front of the aircraft via a transmission shaft 39 provided along the lower abdomen of the aircraft, and then the PTO shaft 41 protrudes backward. Is transmitted to. Further, the power extracted from the PTO shaft 41 is transmitted to the input case 42 provided on the upper portion of the deck of the mower 4 and then transmitted to the plurality of rotating blades 43 supported by the deck. It has become.

  The PTO clutch 35 employs a multi-plate clutch in which friction plates 47 alternately engaged with each other between a driving-side clutch boss 45 and a driven-side clutch drum 46 are superposed to supply pressure oil. As a result, the clutch 48 is shifted against the spring 49 with the piston 48 installed therein, and a clutch disengaged state is generated by draining the piston 48 backward with the spring 49 by draining oil. It has become.

  The clutch drum 46 is equipped with a brake 50 that operates in synchronization with the operation of the PTO clutch 35. The brake 50 rotates on the inner surface of the case between a pressing plate 52 connected to the piston 48 in the clutch drum 46 via a through pin 51 and a friction plate 53 that is splined to the boss portion of the clutch drum 46. The brake plate 54 that is impossiblely engaged is configured to be clamped. When the piston 48 is in the “clutch engaged” state, the clamp plate 54 is released from the pressing plate 52 and the friction plate 53 to release the “brake off”. ”State, and when the piston 48 is in“ clutch disengagement ”, the brake plate 54 is clamped by the pressing plate 52 and the friction plate 53 to bring about the“ brake on ”state.

  FIG. 10 shows a hydraulic circuit diagram of this riding mower.

  In this figure, 61 is a hydraulic pump for pressure supply driven by engine power, 62 is a three-position switching control valve for controlling the operation of a hydraulic cylinder 63 for raising and lowering the mower, and 64 is a grass collecting container. A three-position switching control valve 65 for controlling the operation of the lifting hydraulic cylinder 8, 65 is a three-position switching control valve for controlling the operation of the dump cylinder 11 for opening and closing the grass collection container. The valves 62, 64 and 65 are operated to be switched artificially. Reference numeral 66 denotes a two-position switching control valve that supplies and discharges pressure oil to and from the PTO clutch 35. A control valve 66 for the PTO clutch is connected to the return oil passage d from the cylinder operation control valves 62, 64, 65, and this return oil passage d passes through a filter 67 attached to the transmission case 15. After being purified, it is supplied to the charge oil passage c in each hydraulic continuously variable transmission 20 through a pair of internal oil passages b.

  The hydraulic pump 61 is driven by the second shaft 18 located at the upper part of the transmission case 15, and the lubricating oil stored in the transmission case is taken out from the lower end of the case through the strainer 68 and the pipe 69. The pressure oil sucked and discharged is supplied to the valve block 70 of the control valves 62, 64, 65 through the oil feed pipe 71. Further, the maximum pressure in the return oil passage d is limited by a low-pressure relief valve 72, and drain oil from the relief valve 72 is sent to the upper end of the transmission case 15 and is reduced in the case. The lubricating oil is supplied to the gear group and the bearing group located above the lubricating oil surface in the transmission case 15.

  Here, an oil passage e for sending drain oil from the relief valve 72 to the upper end of the transmission case 15 is formed in the case wall. More specifically, the transmission case 15 has a split structure in which the front and rear divided case portions 15f and 15r are joined and bolted together, and a groove 73 is formed on the joint surface of the rear divided case portion 15r. The oil passage e for supplying lubricating oil is formed between the joint surfaces of the divided case portions 15f and 15r joined and connected.

  The lubricating oil sent to the upper end portion of the transmission case 15 through the oil passage e and reduced in the case is scattered by the gear 74 of the input shaft 16, and a part of the lubricating oil is input to the input shaft. 16, the second shaft 18 and the third shaft 19 are successively flowed down into the support boss portion 75 of the third shaft 19 through the upper and lower notches k, and the bearings 76 that support the shafts 16, 18, and 19 are lubricated. It has become.

  Further, as shown in FIG. 6, an annular narrow groove 80 for sealing is formed so as to surround the groove 73 from the outside over the entire circumference of the joint surface of the split case portion 15r, and is applied to the joint surface. Since the liquid sealing material flows into the annular narrow groove 80, uniform sealing is performed over the entire circumference of the joint surface, and leakage of the lubricating oil from the oil passage e to the outside of the case is reliably prevented. . The grooves 73 forming the oil passage e for feeding the lubricating oil may be formed only on the joint surface of the front split case portion 15f or on the joint surfaces of the front and rear split case portions 15f and 15r. .

  As shown in FIG. 9, drain oil from each hydraulic continuously variable transmission 20 is returned to the upper surface of the transmission case 15 via a hose 81, and a receiving port 82 provided on the wall surface of both hydraulic continuously variable transmissions 20. To be supplied. The receiving port 82 communicates with the inside of the cylindrical shaft 83 through a spline fitting portion 84 between the input shaft 21 of the hydraulic continuously variable transmission 20 and the cylindrical shaft 83 that connects the input shafts 21. The shaft 83 is radially formed with through holes 85 that communicate with the inside and the outside, and the internal lubricating oil flows out into the case by centrifugal force through the through holes 85 due to the rotation of the cylindrical shaft 83, and the surrounding transmission mechanism. It is designed to lubricate. Note that the spline fitting portion 84 between the input shaft 21 and the cylinder shaft 83 is such that the spline teeth of the input shaft 21 are removed only at one place, and the lubricating oil supplied to the receiving port 82 is smoothly brought into the cylinder shaft 83. An oil passage that flows into the nozzle is formed.

  In addition, as shown in FIG. 3, the hose 86 led out from the lower ends of the left and right deceleration cases 23 is connected to the upper surface of the transmission case 15, and the upper portion of the transmission case 15 and the upper portions of the left and right deceleration cases 23 are connected. It is connected by a hose 87 for breathing, so that the lubricating oil is circulated up and down.

Overall side view of a riding lawn mower Transmission system diagram Rear view of rear wheel drive unit Vertical side view of transmission case Vertical section side view of the upper part of the transmission case Front view showing the rear case part of the transmission case AA sectional view in FIG. Longitudinal front view showing the braking system Longitudinal front view showing the power distribution part in the transmission case Hydraulic circuit diagram

Explanation of symbols

15 Transmission case 15f Split case part 15r Split case part 20 Hydraulic continuously variable transmission 73 Groove e Oil path

Claims (2)

  A vertically long transmission case that axially accommodates a transmission gear group is configured in a split structure in which the divided case portion is joined and connected, and a groove is formed in at least one of the joined surfaces of the divided case portion to be joined and connected. A transmission case structure for a working machine, characterized in that an oil passage for supplying lubricating oil to the upper part of the case is formed between joint surfaces of the case part.   An output from the hydraulic continuously variable transmission is configured to be input to the transmission case, and surplus oil of charge oil supplied to the hydraulic continuously variable transmission is configured to be guided to a lower portion of the oil passage. The transmission case structure for a working machine according to claim 1.

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