JP4704966B2 - Shifting structure of work equipment - Google Patents

Description

  The present invention relates to a shift operation structure for a work machine that shifts a transmission operating member built in a transmission case.

  A transmission operation member such as a shift gear or a clutch member of a PTO clutch is incorporated in the transmission case of the work machine so as to be able to perform a shift operation, and the transmission operation member is shifted by various operation structures. ing.

  As one of such shift operation structures, for example, as shown in Patent Document 1, an operation pin is driven and attached to a rotation operation shaft that is rotated from the outside of the case. An inclined cam groove to which the operation pin is engaged is formed in a boss portion of the shifter that is externally fitted so that only sliding is possible, and the shifter is guided by the operation of the operation pin and the inclined cam groove as the rotation operation shaft rotates. A structure for shifting in the axial direction is known.

Japanese Patent Publication No. 3-21370

  The above-mentioned shift operation structure is a practically useful means that allows the shifter to be easily and smoothly shifted by rotating the rotation operation shaft, but machining the inclined cam groove on the boss portion of the shifter In order to form the inclined cam groove with a predetermined cam characteristic along the circumferential direction of the relatively small diameter boss portion, the processing cost is difficult.

  The present invention has been made paying attention to such a point, and has as its main object to make it possible to manufacture a shift operation structure using an inclined cam at low cost.

1st invention is the shift operation structure of the working machine which shift-operates the operation member for transmission built in the mission case,
The operation shaft that is inserted and supported so as to be able to rotate and shift in the transmission case configured in a left and right divided structure and the transmission operating member are engaged and interlocked, and the operation shaft is urged outward. A cam portion for receiving a contact member fixed at a position inside the case of the operation shaft is integrally formed on the inner surface of the case side wall of the left and right split case of the transmission case so as to concentrically surround the operation shaft. An inclined cam surface facing the contact member is formed on an end surface of the cam portion facing inward of the case, and the contact member moves axially through the inclined cam surface as the operation shaft rotates. It is comprised so that it may be moved to.

  According to the above configuration, when the operation shaft is rotated, the contact member is rotated with respect to the fixed cam portion, and the contact member is moved in the axial direction together with the operation shaft by the guide action of the inclined cam surface. The transmission actuating member linked to the shaft is shifted.

  Since the cam portion for moving the contact member in the axial direction is formed integrally with the transmission case, an inclined cam surface with desired cam characteristics can be obtained without requiring machining. Since the cam portion is in the transmission case, the lubricating oil in the case can be always supplied to the sliding contact portion with the contact member, so that a smooth cam operation can be exhibited.

  Therefore, according to the first invention, the shift operation structure using the tilt cam can be manufactured at low cost.

According to a second invention, in the first invention,
The contact member is configured by an operation pin that is driven and connected to the operation shaft in a state of projecting at both ends , and the outer peripheral surface of the projecting portion at both ends of the operation pin is directly received and supported by the end surface of the cam portion. Is.

  According to the above configuration, the contact member can be provided on the operation shaft by simple and inexpensive processing by simply driving the operation pin into the through hole formed in the operation shaft, and at a diagonal position with respect to the axis of the operation shaft. The contact force from the cam portion can be applied to the projecting portions at both ends of the operation pin (contact member), and the operation shaft can be smoothly shifted without twisting.

According to a third invention, in the second invention,
A shift fork engaged with the transmission actuating member is externally fitted to a position inside the case of the operating shaft, and a spring for slidingly urging the shift fork is provided on the left and right sides facing the case side wall where the cam portion is formed. The operation shaft is externally fitted to the operation shaft in a state extending from the inner surface of the case side wall of the other split case to one end side in the axial direction of the shift fork, and the other end side in the axial direction of the shift fork is the operation pin The shift fork and the operation shaft are slidably biased by the spring in an integrated state .

According to the above configuration, the slide biasing force by the spring can be applied to the operation shaft without squeezing, and the operation shaft can be smoothly slid in the axial direction.

The fourth invention is, in one aspect or Re the first to third noise,
The transmission operating member is a slide collar with a claw in a claw-engaged PTO clutch, and the urging direction of the operation shaft is set to the clutch disengagement direction of the slide collar .

According to the above configuration, the slide biasing force that causes the contact member to contact and follow the cam part is used as the clutch disengagement bias force of the PTO clutch, and the biasing spring is a single one. it can.

  1 and 2 show an entire side surface and an entire plane of a walking type management machine as an example of the walking type working machine according to the present invention. In this walking type management machine, a pair of left and right propulsion wheels 1 are pivotally supported, and an engine support frame 3 is extended in a cantilever manner from a mission case 2 that performs forward and backward switching of a plurality of stages. The horizontal axis type engine 4 is mounted and connected to the upper part of the transmission case 2, and a steering handle 5 that can be changed in the front-rear direction is provided at the top of the mission case 2. In this walking type management machine, basically, the side on which the engine 4 is located is the front of the body, and the opposite direction is the rear of the body. To be based on.

  As the engine 4, a recoil start type air-cooled gasoline engine having a cylinder portion whose axis is inclined rearward and configured to be low in volume up and down is used, and a gap between the engine 4 and the transmission case 2 is filled. A fuel tank 6 is provided.

  An output shaft 11 projecting to the left side of the engine 4 and an input shaft 12 projecting to the upper left side of the transmission case 2 are interlocked and connected by a belt transmission mechanism 14 having a tension clutch type main clutch 13. The entire belt transmission mechanism 14 is surrounded by a resin belt cover 15.

  3 to 5 show a transmission structure built in the mission case 2. A back shaft 16 is disposed in front of the input shaft 12 disposed in the upper part of the mission case 2, a second shaft 17 is disposed below the back shaft 16, and further positioned below the input shaft 12. A third shaft 18 is provided. The right end portion of the input shaft 12 is concentrically supported by the inner end portion of the PTO shaft 19 supported through the bearing on the right side surface of the case, and the PTO shaft 19 is driven by the power of the input shaft 12 via the claw-engaged PTO clutch 20. To be communicated to.

  The PTO clutch 20 includes a slide collar 21 with a pawl that is slidably fitted to the input shaft 12 and a clutch boss 22 with a pawl integrally formed on the inner end of the PTO shaft 19. When the slide collar 21 serving as the operating member is engaged with the clutch boss 22, a clutch engagement state in which power is transmitted from the input shaft 12 to the PTO shaft 19 is brought about. When the slide collar is slid backward to release the nail engagement as shown in FIG. 4, a clutch disengagement state in which power transmission from the input shaft 12 to the PTO shaft 19 is cut off is brought about.

  Between the input shaft 12, the back shaft 16, and the second shaft 17, there is interposed a main transmission mechanism 23 that shifts the second shaft 17 to two forward speeds and two reverse speeds. explain.

  A first shift gear SG1 having a small-diameter gear G1 and a large-diameter gear G2 is fitted on the input shaft 12 by a spline so as to be shiftable, and the second shaft 17 is selectively engaged with the small-diameter gear G1 and the large-diameter gear G2. The passive gears G3 and G4 are fixedly fitted. As shown in FIG. 4, when the first shift gear SG1 is in the neutral position, the small diameter gear G1 and the large diameter gear G2 are both disengaged from the passive gears G3 and G4, and the first shift gear SG1 is shifted from the neutral position to the right in the figure. The second shaft 17 is driven at the first forward speed by engaging the small-diameter gear G1 with the passive gear G3. The second shaft 17 is driven at the second forward speed by shifting the first shift gear SG1 from the neutral position to the left in the figure and engaging the large-diameter gear G2 with the passive gear G4.

  A second shift gear SG2 having a small diameter gear G5 and a large diameter gear G6 is fitted on the back shaft 16 by a spline so as to be shiftable. The large-diameter gear G2 of the first shift gear SG1 and the large-diameter gear G6 of the second shift gear SG2 are each configured to be wide so that they are always meshed regardless of how the first and second shift gears SG1 and SG2 are shifted. 16 is rotationally driven in the direction opposite to the input shaft 12. As shown in FIG. 4, when the second shift gear SG2 is in the neutral position, the small diameter gear G5 and the large diameter gear G6 are both disengaged from the passive gears G3 and G4, and the second shift gear SG2 is shifted from the neutral position to the right in the figure. Then, by engaging the small-diameter gear G5 with the passive gear G3, the second shaft 17 is driven at the first reverse speed, the second shift gear SG2 is shifted from the neutral position to the left in the figure, and the large-diameter gear G6 is moved to the passive gear. By engaging with G4, the second shaft 17 is driven at the second reverse speed.

  Between the second shaft 17 and the third shaft 48, an auxiliary transmission mechanism 24 for shifting the power from the second shaft 17 in three stages is interposed, and the transmission structure will be described below.

  A small-diameter gear G7, a large-diameter gear G8, and a small-diameter wide gear G9 are loosely supported on the second shaft 17, respectively. On the third shaft 18, the small-diameter gear G7, the large-diameter gear G8, and Passive gears G10, G11, and G12 that are always engaged with each of the small-diameter wide gear G9 are mounted. While the passive gears G10 and G11 are fixed to the third shaft 18, the passive gear G12 is loosely fitted to the third shaft 18, and an output sprocket 25 is integrally connected to the passive gear G12. Yes. A large-diameter gear G13 is integrally connected to the small-diameter wide gear G9, and this large-diameter gear G13 is always meshed with a pinion gear G14 formed integrally with the third shaft.

  The second shaft 17 is formed in a cylindrical shaft shape, and the shift shift shaft 26 is inserted from the left end thereof so as to be able to be retracted and retracted in the axial direction, and the second shaft 17 has an inner end portion of the shift shift shaft 26. A collar member 28 slidably in contact with the inner periphery is connected. The collar member 28 incorporates a key member 27 that can be displaced back and forth in the radial direction and that is projected and biased by an internal spring 29. The key member is slid in the axial direction by shifting the shift shift shaft 26. 27 is engaged from the inner periphery with any one of the small-diameter gear G7, the large-diameter gear G8, and the small-diameter wide gear G9.

  In a state where the shift gear shaft 26 is pushed inward and slid most inward, the key member 27 is engaged with the small diameter gear G7, and the second shaft 17 and the small diameter gear G7 are integrated. As a result, the power of the second shaft 17 is transmitted to the third shaft 18 via the small diameter gear G7 and the passive gear G10. The power transmitted to the third shaft 18 is decelerated and transmitted to the small-diameter wide gear G9 via the pinion gear G14 and the large-diameter gear G13, and further decelerated via the small-diameter wide gear G9 and the passive gear G12. Driven at low speed.

  As shown in FIG. 4, in the state in which the shift shift shaft 26 is slid to the left and right intermediate position, the key member 27 is engaged with the large diameter gear G8 and the second shaft 17 and the large diameter gear G8 are integrated. . As a result, the power of the second shaft 17 is transmitted to the third shaft 18 via the large-diameter gear G8 and the passive gear G11. The power transmitted to the third shaft 18 is decelerated and transmitted to the small-diameter wide gear G9 via the pinion gear G14 and the large-diameter gear G13, and further decelerated via the small-diameter wide gear G9 and the passive gear G12. Driven at medium speed.

  In a state in which the shift shift shaft 26 is pulled out and slid most outward, the key member 27 is engaged with the small-diameter wide gear G9, and the second shaft 17 and the small-diameter wide gear G9 are integrated. As a result, the power of the second shaft 17 is directly transmitted to the passive gear G12 through the small-diameter wide gear G9, and the output sprocket 25 is driven at a high speed.

  As described above, the sub-transmission mechanism 24 shifts the power transmitted to the second forward speed and the second reverse speed by the main transmission mechanism 23 to the second shaft 17 and further transmits the power to the output sprocket 25. It is configured as follows.

  The speed change power taken out from the output sprocket 25 is transmitted to the left and right axles 29 supported under the mission case 2 as follows.

  As shown in FIG. 5, the left and right axles 29 are concentrically opposed to each other, and an intermediate support shaft 30 is inserted across both axles 29. A collar 31 sandwiched between the left and right axles is loosely fitted to the left and right central portions of the intermediate support shaft 30, and the passive sprocket 32 and the output sprocket 25 that are externally fitted to the collar 31 are connected via a chain 33. It is linked to the winding.

  The passive sprocket 32 and the left and right axles 29 are linked to each other via a ball-type side clutch 34. By inserting both side clutches 34, the left and right axles 29 are driven integrally to travel straight, The vehicle body is steered by one-wheel drive by disengaging the side clutch 34 and putting one axle 29 in the idle state.

  The side clutch 34 has a clutch boss 35 extending left and right from the passive sprocket 32, a transmission ball 36 engaged and supported at a plurality of locations in the circumferential direction of the clutch boss 35, and a shiftable outer fit on the outer periphery of the clutch boss 35. The operation collar 37 is mounted, and a clutch spring 38 that biases and shifts the operation collar 37 outward in the axial direction. Normally, as shown in the left half of FIG. 5, the operation collar 37 is shifted outward by the clutch spring 38, so that the transmission ball 36 is pushed inward in the radial direction on the inner periphery of the operation collar 37. Thus, the transmission ball 36 is engaged with the clutch boss 35 over the transmission groove 29 a formed on the outer periphery of the axle 29, resulting in a clutch engagement state in which transmission from the passive sprocket 32 to the axle 29 is performed. As shown in the right half of FIG. 5, when the operation collar 37 is shifted inward against the clutch spring 38, the push-in of the transmission ball 36 due to the inner periphery of the operation collar 37 is released, and the transmission ball 36. Can be retracted to the inner space 39 of the operation collar, and the transmission ball 36 escapes from the transmission groove 19a of the axle 29, thereby bringing about a clutch disengagement state in which the transmission from the passive sprocket 32 to the axle 29 is interrupted.

  The main clutch 13, the PTO clutch 20, the main transmission mechanism 23, the auxiliary transmission mechanism 24, and the side clutch 34 can be operated from the rear part of the machine body.

[Main clutch operation structure]
On the left side of the steering handle 5, a main clutch lever 41 wire-coupled to the tension arm 13a of the main clutch 13 is disposed so as to be able to swing back and forth around the lateral fulcrum a beyond the dead point. The clutch disengagement position and the clutch engagement position slightly beyond the dead center are switchable and held.

  On the left side of the steering handle 5, an auxiliary clutch lever 42 that can be pushed down with the thumb of the hand that grips the left grip portion 5g of the steering handle 5 is disposed so as to be swingable around the lateral fulcrum b and to be able to return and rise. . The auxiliary clutch lever 42 is linked to the main clutch lever 41 so that the main clutch lever 41 can be forcibly swung from the current operation position to the opposite position every time the push-down operation is performed. Even when the handle 5 is held, the main clutch 13 can be turned on and off by a finger operation.

  An arch-shaped check lever 43 is provided on the left and right of the steering handle 5. The check lever 43 is configured to forcibly swing the main clutch lever 42 to the rear clutch disengagement position when the main clutch lever 41 is swung forward while the main clutch lever 41 is in the clutch engaged position. When the aircraft moves backward without the operator moving, the check lever 43 is pushed by the operator and swung relatively forward, so that the main clutch 13 is automatically cut and the reverse movement is stopped. It is like that.

[PTO clutch operation structure]
As shown in FIG. 6, an operation in which the base end boss 51 a of the shift fork 51 engaged with the slide collar (transmission actuating member) 21 in the PTO clutch 20 is slidably and rotatably supported on the transmission case 2. The shaft 52 is externally fitted. The shift fork 51 is slid in the clutch disengagement direction (leftward in the figure) by a spring 53 that is externally fitted to the operation shaft 52, and the other end of the base end boss 51 a of the shift fork 51 is driven into the operation shaft 52. The shift fork 51 and the operation shaft 52 are integrally slid and biased in the clutch disengagement direction by being received and supported by the penetrating operation pin 54.

The transmission case 2 has a left and right divided structure by aluminum die casting, and a cam portion 55 is integrally formed on the inner surface of the case side wall on the left side so as to surround the operation shaft 52 concentrically. The protruding portions at both ends of the operation pin 54 are received and supported by the inner end portion of the cam portion 55. As shown in FIGS. 7 and 8, the cam portion 55 has two sets of trapezoidal ridges 55a and valleys 55b alternately formed with a 180 ° phase shift, and the flat top and valleys of the trapezoidal ridges 55a. The bottom surface of the portion 55b is connected by an inclined cam surface 55c. Therefore, when the operation shaft 52 is rotated so that the protruding portions at both ends of the operation pin 54 are in a rotation phase that falls into the valley portion 55b, the operation shaft 52 and the shift fork 51 are urged and slid to the clutch disengagement position. When the operation shaft 52 is forcibly rotated from this rotation phase, the projecting portions of the both ends of the operation pin 54 are moved up relative to the flat top of the trapezoidal peak portion 55a via the inclined cam surface 55c, whereby the operation shaft 52 is moved. The shift fork 51 is moved to the clutch engagement position against the spring 53.

  A rotation operation arm 56 is fixed to the projecting portion of the operation shaft 52 outside the case, and the rotation operation arm 56 is wired to a PTO clutch lever 57 that is pivotally supported on the right side of the steering handle 5 so as to be able to swing back and forth. It is linked. The PTO clutch lever 57 is arbitrarily switched between a clutch disengagement position that greatly exceeds the dead point rearward and a clutch engagement position that slightly exceeds the dead point forward and is held at the operation position. Can be done.

[Main / sub transmission mechanism operation structure]
A first shift gear SG1 and a second shift gear SG2 that operate the main transmission mechanism, and a transmission shift shaft 26 that operates the subtransmission mechanism are extended from the upper left side of the transmission case 2 so as to be able to change the direction back and forth. 61, the shift lever 61 is swung up and down to select the first shift gear SG1 and the second shift gear SG2, and the shift shift shaft 26 is shifted, and the shift lever 61 is swung left and right. By operating it, the selected first shift gear SG1 or second shift gear SG2 is operated to shift to shift forward 6 steps and reverse 4 steps. Although a reverse 6-speed shift is possible on the transmission mechanism, the operating range of the shift lever 61 is limited to prevent the reverse high-speed stage from appearing.

[Side clutch operation structure]
As shown in FIG. 3, the operation collars 37 in the left and right side clutches 34 are engaged with shift forks 65 supported in the mission case 2 so as to be swingable around a fulcrum s in the front-rear direction, and left and right shift forks 65 are respectively engaged. Is linked to a clutch operation shaft 66 provided at the upper and lower intermediate portions of the left and right side surfaces of the transmission case 2 via an operation rod 67. An operating arm 68 provided at the outer end of the clutch operating shaft 66 and a grip lever 69 provided on the left and right of the steering handle 5 are respectively linked by wire, and the grip portion 5g of the steering handle 5 and the grip lever 69 are connected together. By performing a grip operation, the side clutch 34 on the gripped side is turned off.

[Other Examples]
The present invention can also be implemented in the following forms.

  (1) The spring 53 is externally fitted to the input shaft 12, and the slide collar (transmission actuating member) 21 is directly slid in the clutch disengagement direction by the spring 53, and this urging force is transmitted via the shift fork 51 In this manner, the operation shaft 52 can be transmitted.

  (2) Instead of the operation pin 54, a collar can be externally fixed to the operation shaft 52 to be a contact member facing the cam portion 55.

  (3) The transmission operation member such as a shift gear for shifting or a shift collar for shifting can be shifted by rotating the operation shaft 52.

Overall side view of walking management machine Overall plan view of walking-type management machine Longitudinal rear view of the mission case Longitudinal rear view at the top of the mission case Longitudinal rear view at the bottom of the mission case Cross-sectional plan view showing the PTO clutch and its operating structure Side view of cam part for PTO clutch operation as seen from inside the case Developed cam part

2 Mission case 21 Actuating member for transmission (slide collar)
51 Shift fork 52 Operation shaft 53 Spring 54 Contact member (operation pin)
55 Cam part 55c Inclined cam surface

Claims (4)

A shift operation structure of a work machine that shifts a transmission actuating member built in a transmission case,
The operation shaft that is inserted and supported so as to be able to rotate and shift in the transmission case configured in a left and right divided structure and the transmission operating member are engaged and interlocked, and the operation shaft is urged outward. A cam portion for receiving a contact member fixed at a position inside the case of the operation shaft is integrally formed on the inner surface of the case side wall of the left and right split case of the transmission case so as to concentrically surround the operation shaft. An inclined cam surface facing the contact member is formed on an end surface of the cam portion facing inward of the case, and the contact member moves axially through the inclined cam surface as the operation shaft rotates. A shift operation structure of a work machine, characterized in that it is configured to be moved to a position. The contact member is configured by an operation pin that is driven and connected to the operation shaft in a state of projecting at both ends , and the outer peripheral surface of the projecting portion at both ends of the operation pin is directly received and supported by the end surface of the cam portion. The shift operation structure of the working machine according to claim 1. A shift fork engaged with the transmission actuating member is externally fitted to a position inside the case of the operating shaft, and a spring for slidingly urging the shift fork is provided on the left and right sides facing the case side wall where the cam portion is formed. The operation shaft is externally fitted to the operation shaft in a state extending from the inner surface of the case side wall of the other split case to one end side in the axial direction of the shift fork, and the other end side in the axial direction of the shift fork is the operation pin The shift operation structure for a working machine according to claim 2, wherein the shift fork and the operation shaft are configured to be slid and biased by the spring in an integrated state . The power transmission actuating member is a sliding collar with nails in PTO clutch pawls bite type, the biasing direction of the operation shaft, any one of claims 1 to 3 that is set on clutch disengaging direction of the slide collar one The shift operation structure of the work machine as described in the item .

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