JP6333151B2 - Steering mechanism - Google Patents

Description

  The present invention relates to a steering operation mechanism disposed in a mission case used as a drive device for a traveling vehicle such as a combine.

  Conventionally, as one form of the steering operation mechanism disposed in the mission case, there is one disclosed in Patent Document 1. That is, the steering operation mechanism disclosed in Patent Document 1 has a steering operation shaft installed horizontally in a mission case, and a steering transmission gear linked to the engine is attached to the center of the steering operation shaft. Positioned on both sides of the transmission gear, a pair of cylindrical sliding bodies are slidably fitted on the steering operation shaft, and side gears are integrally formed on the outer peripheral surface of each sliding body, while a driving shaft (axle) A pair of left and right reduction gears is attached to each of the two, and the reduction gears and the side gears are engaged with each other. A side clutch capable of power connection / disconnection is formed between the inner end of each sliding body and the side wall of the drive gear, while a plurality of movable parts can be moved along the axis of the outer part of the outer peripheral surface of each sliding body. A side friction plate is arranged, and a plurality of fixed friction plates are arranged facing each other between the movable friction plates along the axis on the inner peripheral surface of the brake case fixed to the transmission case to form a side brake. ing. Then, a pressing spring is wound around the outer peripheral surface of the steering operation shaft, and the sliding body is pressed and biased inward to make the side clutch connected.Each sliding body is engaged with a shift fork, The side clutch can be disengaged by sliding each sliding body outward against the urging force of the pressing spring via the shift fork, and the side brake can be braked by sliding further outward. It is said. Also, in the mission case, there is a so-called oil bath lubrication type in which lubricating oil is contained to the extent that the side brakes are immersed, and the lubricity of the rotating components that rotate in the mission case is ensured. It has been adopted.

JP2013-129382A

  However, in the oil bath type steering operation mechanism described above, the lubricating oil stays in the space where the pressure spring is accommodated or in the space where the space and the side brake communicate with each other. The generated heat is propagated to the staying lubricating oil to increase the temperature of the lubricating oil, and the increased temperature of the lubricating oil deteriorates the friction plate of the side brake, thereby shortening the life of the friction plate.

  Accordingly, an object of the present invention is to provide a steering operation mechanism that can extend the life of a friction plate of a side brake by eliminating the retention of lubricating oil and increasing the temperature.

Steering operation mechanism according to the first aspect of this invention,
A cylindrical sliding body with an integrally formed side gear is slidably fitted to a steering operation shaft that is installed horizontally in an oil bath lubrication type transmission case, and a multi-plate side brake is provided on the outer periphery of the sliding body. The steering operation mechanism that enables the intermittent operation of the power by interlocking the sliding operation of the sliding body and the brake braking operation of the side brake,
The sliding body and the side brake are each formed with a sliding body oil flow passage and a brake oil flow passage through which lubricating oil flows in the radial direction of the steering operation shaft, and the both oil flow passages are communicated with each other. .

In the steering operation mechanism according to the first aspect , in the oil bath lubrication type transmission case, a space formed between the outer peripheral surface of the steering operation shaft and the inner peripheral surface of the sliding body, and the outer periphery of the sliding body The space formed between the surface and the inner peripheral surface of the side brake is communicated through the sliding body oil flow passage, and is formed between the outer peripheral surface of the sliding body and the inner peripheral surface of the side brake. The space and the outer peripheral space of the side brake communicate with each other via the brake oil flow passage, and both the oil flow passages communicate with each other. Therefore, when the side brake is braked, the space is accommodated in the space. The lubricated oil is subjected to a pressing action (so-called pumping action) caused by the braking operation of the side brake, and flows out from the space accommodated through both oil flow passages. Therefore, the lubricating oil in the space does not stay in the space. And even if the heat generated during braking of the side brakes is propagated to the lubricating oil, it is diffused to the lubricating oil outside the space and is not heated up. Therefore, the friction plate of the side brake is not deteriorated by the high temperature. As a result, the life of the friction plate can be extended.

Steering operation mechanism according to the second aspect of this invention is a steering operation mechanism according to the first aspect,
The side brake has a plurality of saddle-shaped movable friction plates arranged along the axis on the outer peripheral surface of the sliding body, and a plurality of side brakes along the axis along the inner peripheral surface of the brake case fixed to the transmission case. Brake-shaped fixed-side friction plates are arranged facing each other between the movable-side friction plates, and the sliding body is slid to bring the fixed-side friction plate and the movable-side friction plate into surface contact with each other in a pressed state. It can be braked,
The sliding body is provided with a recessed space in the inner peripheral surface portion thereof, and accommodates a pressing spring disposed around the steering operation shaft in the recessed space, and in a sliding direction in which the side brake is non-brake braked by the pressing spring. To be urged,
The sliding body oil flow passage is formed in a through hole penetrating the peripheral wall portion provided with the recessed space in the sliding body,
The brake oil flow passage includes a groove groove formed on the opposite side of the fixed friction plate and the movable friction plate in alignment with each other, and an opening formed in communication with the groove groove in the brake case. It is characterized by being formed from.

In the steering operation mechanism according to the second aspect , the sliding body oil flow passage is formed in the through-hole penetrating the peripheral wall portion provided with the recessed space in the sliding body, while the brake oil flow passage is formed by the fixed side friction. It is formed from a groove groove formed on the opposite side of the plate and the movable friction plate in alignment with each other and an opening formed in the brake case in communication with the groove groove, and both oil flows Since the roads are in communication, it is possible to prevent the lubricating oil in the recessed space from flowing out of the side brakes steadily through both oil flow passages and the lubricating oil from staying in the recessed space.

Steering operation mechanism according to the third aspect of the invention this is a steering operation mechanism through hole according to the second aspect, as to form a plurality at intervals in the axial direction of the slide, sliding Brake oil flow passage formed by the sliding body oil flow passage formed in the through hole, the concave groove and the opening at the power cutting position where the sliding operation of the moving body and the brake braking operation of the side brake are interlocked. Are aligned and communicated with each other in the radial direction of the steering operation shaft, and the recess space and the outer peripheral portion of the brake case communicate with each other through both oil flow passages.

In the steering operation mechanism according to the third aspect , the sliding body oil flow passage and the brake oil flow passage perform the steering operation at the power cutting position where the sliding operation of the sliding body and the brake braking operation of the side brake are interlocked. Since the recess space communicates with the outer periphery of the brake case through both oil flow passages in alignment with each other in the radial direction of the shaft, a pumping action causes the inside of the recess space during braking. Lubricating oil flows out smoothly and firmly to the outer periphery of the brake case. Further, the lubricity of the fixed side friction plate and the movable side friction plate via the concave groove is also ensured, and the brake performance of the side brake can be ensured well.

  ADVANTAGE OF THE INVENTION According to this invention, it can eliminate that the lubricating oil stagnates and is heated up, and can provide the steering operation mechanism which can attain the life extension of the friction plate of a side brake.

The side view of the combine which concerns on this embodiment. The front view of the combine which concerns on this embodiment. A sectional front view of a mission case. The partially expanded front view of a mission case. The principal part expanded sectional front view. The principal part expanded sectional front explanatory drawing. II sectional view explanatory drawing of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. That is, A shown in FIGS. 1 and 2 is a normal combine according to the present embodiment. First, the overall configuration of the combine A will be schematically described.

[Schematic description of the overall structure of the combine]
The combine A has the cutting part 2 attached to the front end part of the traveling machine body 1 capable of self-running so as to be movable up and down.

  As shown in FIGS. 1 and 2, the traveling machine body 1 has a machine body frame 11 installed between a pair of left and right traveling units 10 and 10. And on the left side of the machine body frame 11, a threshing portion 12 for threshing the side portion of the harvested cereal head and a sorting portion 13 for sorting the threshed grain are arranged in the upper and lower stages. A waste disposal processing unit 14 that shreds waste into the rear and discharges sawdust and the like to the field outside the machine is opened rearward. In addition, on the right side of the machine body frame 11, a driving unit 15 that performs a driving operation is disposed in the front part, and a grain storage unit that stores the grain (clean grain) selected by the screening unit 13 behind the driving unit 15. 16 is disposed, and a grain unloading part 17 for unloading the grains stored in the grain storing part 16 to the outside is provided at the rearmost part. Below the rear part of the operation unit 15, an engine 18 or the like as a prime mover unit serving as a power source is disposed.

  The mowing unit 2 is formed in a rectangular cylinder shape with its axis line in the front-rear direction and has a feeder house 19 incorporating a supply conveyor, and a horizontally long bucket-shaped grain header 21 that is continuously connected to the front end opening of the feeder house 19. A clipper-shaped cutting blade device 20 disposed at the front lower end edge of the grain header 21, and a pair of left and right weed bodies 22 and 22 formed to extend forward from the front left and right sides of the grain header 21; A take-up reel 23 disposed in front of the grain header 21 is provided.

  The rear end portion of the feeder house 19 pivotally supports a cutting input shaft (not shown) having a horizontal axis directed to the front portion of the threshing portion 12, and the lower surface portion of the feeder house 19 and the front end portion of the body frame 11 The raising / lowering cylinder 24 is interposed, and the raising / lowering cylinder 24 is expanded and contracted, whereby the cutting portion 2 can be raised and lowered with a cutting input shaft (not shown) as a lifting fulcrum.

  Further, the take-up reel 23 is pivoted between the distal ends of a pair of left and right reel support arms 23a, 23a pivotally supported by the grain header 21 so as to be rotatable about a horizontal axis. While rotating to the tip of the hair cereal, the squeezing action is continuously applied to the side of the auger (not shown) disposed in the grain header 21. The operation parts of the respective parts described above are configured to be interlocked with the engine 18 so as to operate appropriately.

  In the combine A comprised in this way, in the agricultural field, the cutting part 2 is raised until it becomes a desired ground height (a cutting position of the napped grain basket), and the traveling machine body 1 is made to travel in that state. By doing so, the napped cedar is sown by the weeds 22, 22, and the cutting part 20 is scraped from the middle part of the cereal by the cutting blade device 20 while being scraped by the scooping reel 23. Mow the side of the tip. The tip side portion of the grain culm cut at the desired cutting position is scraped into the grain header 21 by the scraping auger and supplied to the threshing section 12 through the feeder house 19 by the supply conveyor. The tip side portion of the cereal supplied to the threshing unit 12 is threshed by the threshing unit 12, and the grain threshed by the threshing unit 12 is subjected to a sorting process by the sorting unit 13. The grain (clean grain) subjected to the sorting process by the sorting unit 13 is stored in the grain storage unit 16. The grain stored in the grain storage unit 16 is appropriately carried out of the machine by the grain carrying-out unit 17. Then, the waste that has been separated from the grain by the threshing unit 12 is shredded, and the sawdust and the like are discharged from the processing unit 14 such as the waste to the field outside the machine.

  A mission case 30 that is formed vertically long in the vertical direction is attached to the front of the body frame 11, and the mission case 30 hangs the lower half from the body frame 11. A transmission belt 35 is wound between the input shaft 51 provided on the upper left side of the mission case 30 and the drive shaft 32 of the engine 18 via the input pulley 33 and the drive pulley 34, and the mission case 30 is wound around the engine 18. Are linked together.

  As shown in FIG. 3, shaft cases 36, 36 extending in the left-right direction are extended from the left and right lower portions of the mission case 30, and the outer end portions of the shaft cases 36, 36 are a pair of left and right traveling portions. 10 and 10 are connected to front end portions of travel frames 37, 37 via bearing bodies 38, 38. An axle 39 is inserted through each shaft case 36 and mounted on the shaft. A driving wheel 40 is attached to the outer end of the axle 39. The traveling frame 37 is formed by extending in the front-rear direction, a driven wheel 41 is attached to the rear end portion, and a crawler belt 42 is wound between the wheels 40, 41. 43 is a rolling wheel.

  Next, the configuration of the mission case 30 will be described with reference to FIGS. 3 and 4. That is, the transmission case 30 includes an input shaft 51 that takes in power from the engine 18 in a casing 50, a hydraulic continuously variable transmission 52 that includes a hydraulic pump and a hydraulic motor that continuously change the rotational force of the input shaft 51, and A sub-transmission shaft 55 coupled to the transmission output shaft 53 of the hydraulic continuously variable transmission 52 via an idle shaft 54; a counter shaft 57 coupled to the sub-transmission shaft 55 via a sub-transmission gear 56 and a counter gear 66; A parking brake 58 provided on the counter shaft 57, a steering operation shaft 60 that supports a pair of left and right side clutches 59 of a dog clutch pawl type (dog clutch type), and a pair of left and right side brakes 80 provided on the steering operation shaft 60 And a reduction shaft 62 connected to the steering operation shaft 60, and left and right axles 39 connected to the reduction shaft 62.

  Reference numeral 63 denotes a brake arm. A brake pedal (not shown) is connected to the parking brake 58 via the brake arm 63, and the operator depresses the brake pedal to brake the parking brake 58. The traveling units 10 and 10 are configured to brake simultaneously. 64 is a pair of left and right first reduction gears loosely fitted to the reduction shaft 62 and 65 is a second reduction gear attached to the inner end of the axle 39. The pair of side gears 73 and 73 and the pair of left and right first reduction gears 64 and 64 are engaged with each other, and the left and right first reduction gears 64 and 64 and the left and right second reduction gears 65 and 65 are engaged with each other. The crawler belts 42, 42 are driven to rotate forward or reversely via drive wheels 40, 40 provided on the left and right axles 39, 39 so that the traveling machine body 1 moves forward or backward.

  The steering operation shaft 60 constitutes a part of the steering operation mechanism 70, and the steering operation mechanism 70 loosely fits the steering transmission gear 71 at the center of the steering operation shaft 60 so as to roll. Then, a pair of left and right cylindrical sliding bodies 72, 72 are slidably fitted on the steering operation shaft 60 so as to be positioned on both sides of the steering transmission gear 71, and side gears 73 are fitted to the outer peripheral surface of each sliding body 72. , 73 are integrally formed by projecting in a bowl shape, and a pair of left and right first reduction gears 64, 64 loosely fitted to the reduction shaft 62 are engaged with the side gears 73, 73, and the first reduction gears 64, 64 are engaged. Are engaged with a pair of left and right second reduction gears 65, 65 attached to the inner end of the axle 39.

  A side clutch 59 capable of power connection / disconnection is formed between the inner end of each sliding body 72 and the side wall of the steering transmission gear 71, and the side clutch 59 is an inner end of each sliding body 72. The one side clutch forming piece 59a integrally formed with the steering transmission gear 71 and the other side clutch forming piece 59b integrally formed on the side wall of the steering transmission gear 71 are formed so as to be able to be engaged and released. A plurality of movable friction plates 82 are arranged along the axis on the outer side of the outer peripheral surface of each sliding body 72, while the inner peripheral surface of the brake case 81 fixed to the casing 50 has an axis along the axis. A plurality of fixed side friction plates 83 are arranged in a face-to-face state between the movable side friction plates 82 so as to form the side brake 80.

  Then, a pair of left and right pressing springs 90, 90 are wound around the outer peripheral surface of the steering operation shaft 60, and the respective sliding bodies 72, 72 are urged inward by the respective pressing springs 90, 90. Each side clutch 59, 59 is in a connected state. The sliding bodies 72, 72 are engaged with the tip portions 96, 96 of a pair of shift forks 95, 95, respectively. In addition, a so-called oil bath lubrication type in which lubricating oil is accommodated in the casing 50 to such an extent that the side brake 80 is immersed, and the lubricity of the rotating components rotating in the casing 50 is ensured. It is done. Reference numeral 97 denotes a midway pivot portion of the shift fork 95, and 98 denotes a shift operation shaft portion (see FIG. 7).

  In the steering operation mechanism 70 configured as described above, by operating the shift operation portions 98, 98, the front end portions 96, 96 of the shift forks 95, 95 are moved in the left-right direction around the midway pivot portions 97, 97. By swinging, the sliding bodies 72 can be slid in the left-right direction along the steering operation shaft 60. That is, the side clutches 59 and 59 can be disconnected by sliding the sliding bodies 72 and 72 outwardly against the urging force of the pressing springs 90 and 90 via the shift forks 95 and 95, respectively. The side brakes 80 and 80 can be braked by sliding outward. Further, the sliding bodies 72, 72 are slid inward, which is the urging force direction of the pressing springs 90, 90, via the shift forks 95, 95, so that the side clutches 59, 59 are connected and the side brakes are connected. 80 and 80 can be released from braking.

[Description of characteristic structure of steering operation mechanism]
Next, a characteristic configuration of the steering operation mechanism 70 will be described with reference to FIGS. That is, the steering operation mechanism 70 forms the sliding body oil flow passage 100 and the brake oil flow passage 200 through which the lubricating oil flows in the radial direction of the steering operation shaft 60 in the sliding body 72 and the side brake 80, respectively. Both oil flow passages 100 and 200 are communicated. The side brake 80 is fixed to the casing 50 while disposing a plurality of bowl-shaped movable friction plates 82 projecting outward along the axis on the outer side of the outer peripheral surface of the sliding body 72. A plurality of fixed-side friction plates 83 are arranged on the inner peripheral surface portion of the peripheral wall portion of the brake case 81 so as to face each other between the movable-side friction plates 82 so as to protrude inward, and a sliding body 72 is provided. Brake braking is possible by sliding and bringing the fixed-side friction plate 83 and the movable-side friction plate 82 into surface contact with each other in a pressed state.

  The sliding body 72 is formed with a stepped recess 72 a on the inner peripheral surface thereof, a recess space 91 is formed in the stepped recess 72 a, and is wound around the outer peripheral surface of the steering operation shaft 60 in the recess space 91. The pressing spring 90 is accommodated, and the side spring 80 is pressed and urged by the pressing spring 90 in the inward sliding direction in which non-brake braking is performed.

  The sliding body oil flow passage 100 has a straight through hole 110 penetrating in a radial direction in a peripheral wall portion 72b in which a stepped recess 72a is formed in the slide body 72 and a recess space 91 is provided in the stepped recess 72a. Formed inside. Two through-holes 110 are formed in a virtual cross section perpendicular to the axis of the steering operation shaft 60 at intervals of 180 degrees in the circumferential direction and are formed by extending in the radial direction. A plurality (four in this embodiment) of virtual cross sections in which the holes 110 are formed are also spaced in the axial direction of the sliding body 72.

  The brake oil flow passage 200 is formed by a groove groove 210 formed on each side surface of the movable friction plate 82 and an opening 220 formed in the brake case 81 so as to communicate with the groove groove 210.

  The concave groove 210 includes a vertical groove 211 that extends straight from the inner peripheral end to the outer peripheral end on both sides of the movable friction plate 82, and a horizontal groove 212 that extends perpendicularly to the vertical groove 211. Are formed in a lattice pattern. When the fixed friction plate 83 and the movable friction plate 82 are brought into surface contact with each other in the braking state, the groove groove 210 formed in the movable friction plate 82 is communicated with the opening 220 and brakes. An oil flow passage 200 is formed. In this embodiment, the groove groove 210 is formed on both side surfaces of the movable friction plate 82. However, the groove groove 210 may be formed on both side surfaces of the fixed friction plate 83. It can also be formed on the plates 82 and 83.

  The opening 220 extends in the axial direction of the peripheral wall portion formed in the cylindrical shape of the brake case 81 and is formed in a long hole shape that opens in the radial direction, so that the circumferential direction of the peripheral wall portion of the brake case 81 is formed. A plurality (12 in this embodiment) are formed at intervals.

  The base end portion of the brake oil flow passage 200 communicates with an intermediate space 300 formed between the outer peripheral surface of the sliding body 72 and the inner peripheral surface of the side brake 80, and the intermediate space 300 is a sliding body oil flow passage. It communicates with the tip of 100. That is, the sliding body oil flow passage 100 and the brake oil flow passage 200 communicate with each other via the intermediate space 300.

  Then, at the power cutting position where the sliding operation of the sliding body 72 and the brake braking operation of the side brake 80 are interlocked, the sliding body oil flow passage 100 formed in the through hole 110, the concave groove 210 and the opening 220 are provided. And the brake oil flow passage 200 formed in communication with each other in alignment with the radial direction of the steering operation shaft 60, and the outer peripheral portion of the recess space 91 and the brake case 81 via both oil flow passages 100 and 200. And communicate with each other.

  More specifically, in FIG. 6, “a” indicates the direction of the outflow of the lubricating oil, “b” indicates the rotational operation direction of the shift fork 95 during the braking operation, and “c”. Indicates a sliding action direction in which the front end portion 96 of the shift fork 95 slides on the sliding body 72 during a brake braking operation. When the shift fork 95 is rotated in the rotational operation direction b (brake braking operation), the tip 96 of the shift fork 95 slides the sliding body 72 in the sliding direction c, and the side brake 80 is braked. Can be made. At this time, the lubricating oil in the recessed space 91 is pressed by the braking operation of the side brake 80 and flows out into the flow direction a, that is, the inner space 400 of the casing 50 that is the outer peripheral portion of the brake case 81. The

  The steering operation mechanism 70 configured as described above is formed between the outer peripheral surface of the steering operation shaft 60 and the inner peripheral surface of the sliding body 72 in the casing 50 of the oil bath lubrication type mission case 30. The space, that is, the recess space 91, and the intermediate space 300 formed between the outer peripheral surface of the sliding body 72 and the inner peripheral surface of the side brake 80 are communicated via the sliding body oil flow passage 100, and The intermediate space 300 formed between the outer peripheral surface of the sliding body 72 and the inner peripheral surface of the side brake 80 and the outer peripheral space of the side brake 80, that is, the inner space 400 of the casing 50 are the brake oil flow passage 200. It is communicated through.

  When the side brake 80 is braked, the lubricating oil contained in the recessed space 91 and the intermediate space 300 is pressed by a braking action of the side brake 80 (so-called pumping action). ) And flows out smoothly into the inner space 400 of the casing 50 from the inside of the recessed space 91 and the intermediate space 300 through both the oil flow passages 100 and 200. Therefore, the lubricating oil in the recessed space 91 and the intermediate space 300 is steadily discharged to the inner space 400 of the casing 50 that is outside the side brake 80 through both the oil flow passages 100 and 200, so The lubricating oil can be prevented from staying in the space 300.

  Thus, since the lubricating oil in the recessed space 91 and the intermediate space 300 does not stay in the recessed space 91 and the intermediate space 300, the heat generated during braking of the side brake 80 is Even if propagating to the lubricating oil in the space 91 or the intermediate space 300, the lubricating oil in the recessed space 91 or the intermediate space 300 flows out into the internal space 400 and is diffused into the lubricating oil in the internal space 400. As a result, the lubricating oil in the recessed space 91 and the intermediate space 300 is not heated. Therefore, the friction plates 82 and 83 of the side brake 80 are not deteriorated by the high temperature. As a result, the life of the friction plates 82 and 83 can be extended.

When the side brake 80 is released, the relatively low temperature lubricating oil in the inner space 400 of the casing 50 passes through the oil flow passages 100 and 200 into the recessed space 91 and the intermediate space 300. you inflows.

  Thus, the relatively high temperature lubricating oil in the recessed space 91 and the intermediate space 300 flows out of the side brake 80, while the relatively low temperature lubricating oil in the inner space 400 of the casing 50 is Since the oil flows into the brake 80, the lubricating oil in the recessed space 91 and the intermediate space 300 can be prevented from staying at a high temperature, and the fixed friction plate 83 via the recessed groove 210 can be avoided. In addition, the lubricity of the movable friction plate 82 can be secured well, and the brake performance of the side brake 80 can be secured well.

A Combine 30 Mission case 60 Steering operation shaft 70 Steering operation mechanism 80 Side brake 100 Sliding body oil flow passage 200 Brake oil flow passage 210 Concave groove 220 Opening

Claims (3)

A cylindrical sliding body with an integrally formed side gear is slidably fitted to a steering operation shaft that is installed horizontally in an oil bath lubrication type transmission case, and a multi-plate side brake is provided on the outer periphery of the sliding body. The steering operation mechanism that enables the intermittent operation of the power by interlocking the sliding operation of the sliding body and the brake braking operation of the side brake,
The side brake has a plurality of saddle-shaped movable friction plates arranged along the axis on the outer peripheral surface of the sliding body, and a plurality of side brakes along the axis along the inner peripheral surface of the brake case fixed to the transmission case. Brake-shaped fixed-side friction plates are arranged facing each other between the movable-side friction plates, and the sliding body is slid to bring the fixed-side friction plate and the movable-side friction plate into surface contact with each other in a pressed state. It can be braked,
A concave space in which lubricating oil is accommodated is formed in the inner peripheral surface portion of the sliding body,
The sliding body is sliding body oil passage lubricating oil flows in the radial direction of the steering operation shaft is formed,
Concave grooves are formed on both sides of the movable friction plate, and an opening is formed in the brake case.
During braking of the side brake, the groove groove and the opening are communicated to form a brake oil flow passage through which lubricating oil flows in the radial direction of the steering operation shaft,
The lubricating oil in the recessed space is pressed by the pressing action caused by the braking operation of the side brake,
The steering operation mechanism characterized in that the lubricating oil in the recess space flows out to the outer peripheral portion of the brake case via the sliding body oil flow passage and the brake oil flow passage . An intermediate space is formed between the outer peripheral surface of the sliding body and the inner peripheral surface of the side brake.
The sliding body oil flow passage connects the recessed space and the intermediate space,
2. The steering operation mechanism according to claim 1, wherein the brake oil flow passage allows the intermediate space and the outer peripheral portion of the brake case to communicate with each other when braking the side brake . The sliding body accommodates a pressing spring disposed around the steering operation shaft in the recess space, and is pressed and urged by the pressing spring in a sliding direction in which the side brake is not braked. The steering operation mechanism according to claim 1 or 2, characterized by the above.

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