JP2016102527A - transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the possibility that foreign matter in a mission case is drawn to a slide interface between a piston member and a cylinder chamber.SOLUTION: A transmission includes a piston member 101 inserted into a lateral cylinder chamber 100 and supported in a slidable manner. Of an insertion place of the piston member 101 to the cylinder 100, at a place that is at a position drawn into the cylinder chamber 100 in a most retreat-in position and is equivalent to a position exposed to the outside of the cylinder chamber 100 in the most retreat-in position, a recess part 101c opened upwardly is formed so as to form a space between itself and a downward surface of the cylinder chamber 100.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a transmission including a lateral cylinder chamber that opens into a space inside a mission case, and a piston member that is inserted into the cylinder chamber and supported slidably.

As the above mission case, for example, there is a structure described in [1] below.
[1] A piston chamber (cylinder chamber) provided on the inner surface side of the transmission case is provided with a hydraulic piston (piston member) having the same cross-sectional shape as the piston chamber so as to be slidable (see, for example, Patent Document 1) ).

JP 2001-80391 A (refer to paragraphs “0063” and “0064” and “FIG. 12” in the drawings)

In the thing of the structure shown by patent document 1, the piston member is formed in the same cross-sectional shape as a cylinder chamber. This is a general structure for operating the operated member while reducing hydraulic leakage.
This structure has room for improvement in that it has the following problems. That is, when the piston member that protrudes from the cylinder chamber retreats into the cylinder chamber, if fine foreign matter such as friction powder from the gear in the transmission case accumulates on the upward surface of the protruding piston member, There is a possibility that the deposit is drawn between the sliding contact surfaces of the piston member and the cylinder chamber, and the respective sliding contact surfaces are damaged.

  The present invention is intended to reduce the possibility that foreign matter in the mission case is drawn between the sliding contact surfaces of the piston member and the cylinder chamber.

  The technical means in the transmission of the present invention has the following structural features and operational effects.

[Solution 1]
The technical means of the present invention taken in order to solve the above-described problems includes a lateral cylinder chamber that opens into the space inside the mission case, and a piston member that is slidably supported by being inserted into the cylinder chamber. The piston member is inserted into the cylinder chamber, and the most retracted position set on the inner back side, and the most protruded position set closer to the opening side of the cylinder chamber than the most retracted position. The piston member is configured to be capable of reciprocating within a predetermined sliding range, and is in a position where the piston member is retracted into the cylinder chamber at the most retracted position, and In the most protruding position, a concave portion opened upward is formed at a position corresponding to a position exposed to the outside of the cylinder chamber so as to form a space between the downward surface of the cylinder chamber.

[Operation and effect of invention according to Solution 1]
According to the invention relating to the above solution 1, the portion of the piston member corresponding to the position exposed to the outside of the cylinder chamber has a concave portion opened upward so as to form a space with the downward surface of the cylinder chamber. Is formed.
Therefore, in a state where the piston member is in a position where it is drawn into the cylinder chamber, the foreign matter accumulated on the concave portion opened upward is located in a space between the downward surface of the cylinder chamber and the upper surface of the concave portion. There is little possibility of being drawn between the sliding contact surfaces of the piston member and the cylinder chamber.
Thereby, there is an advantage that the possibility that the sliding contact surface between the piston member and the cylinder chamber is damaged can be reduced.

[Solution 2]
Another technical means of the present invention taken in order to solve the above-mentioned problems is that the cylinder chamber and the piston member are formed in a hollow cylindrical shape, and the inner side of the piston member with respect to the outer circumferential surface of the cylinder chamber. The facing peripheral surface is in sliding contact, and the concave portion is formed on the inward peripheral surface of the piston member.

[Operation and effect of invention according to Solution 2]
According to the invention relating to the above solution 2, there is an advantage that wear on the sliding contact surfaces of the cylinder chamber and the piston member formed in a hollow cylindrical shape can be reduced.

[Solution 3]
Another technical means of the present invention taken in order to solve the above-described problem is that a seal that is in sliding contact with the opposing peripheral surface of the piston member is provided on each of the outward peripheral surface and the inward peripheral surface in the cylinder chamber. Among the sealing materials, the sealing material provided near the opening of the cylinder chamber includes a plurality of sealing materials provided on an outer circumferential surface or an inward circumferential surface, and an outer circumferential surface thereof. Another sealing material provided on the surface or the circumferential surface facing the inward circumferential surface is displaced forward and backward in the reciprocating operation direction of the piston member, and between the plurality of sealing materials That is, another sealing material is disposed.

[Operation and effect of invention according to Solution 3]
According to the invention relating to the solution means 3 described above, the piston member is pushed out by the sealing material located on the inner back side due to the presence of a plurality of sealing materials that are displaced in the front-rear direction in the reciprocating direction of the piston member. The pressure oil leakage is effectively utilized while sharing the role of the sealing material, such as suppressing the leakage of the pressure oil during the operation and suppressing the entry of foreign matter by the sealing material located on the open end side of the oil chamber. And foreign matter intrusion can be suppressed.
In addition, the piston member reciprocating operation direction is compared with a structure in which one seal member is provided on each of the inner peripheral surface side and the outer peripheral surface side of the oil chamber to support the pressing piston at two points. By providing a plurality of sealing materials that are displaced from each other in front and rear, there is also an advantage that the posture of the pressing piston can be stably supported.

[Solution 4]
Another technical means of the present invention taken in order to solve the above-mentioned problem is that the piston member is in a reciprocating operation direction, and is adjacent to the piston member via a thrust bearing along the reciprocating operation direction. The rotary operation body includes a rotary operation body that can reciprocate and rotate, and includes a drive rotation body that interrupts driving force with respect to the rotation operation body, and the rotation operation body and the drive rotation body are formed on mutually opposing surfaces. The pawl clutch is configured such that the driving force is intermittently provided by the pawl clutch provided with the pawl portion, and the pawl clutch engages the pawl portions with the transition of the piston member to the most retracted position side. It is configured to be in a combined state, and to be in a cut state in which the claw portions are separated from each other as the piston member moves to the most projecting position side.

[Operations and effects of invention according to Solution 4]
According to the invention relating to the solution means 4 described above, it is possible to effectively suppress foreign matter intrusion between the cylinder chamber and the piston member used for the operation of the rotary operation body and the drive rotary body in which the driving force is interrupted by the pawl clutch. The means to do was obtained.
That is, in the clutch-engaged state where the rotary operation body and the drive rotary body are engaged, the thrust bearing and the rotary operation body are close to each other on the open side of the space on the upward concave portion where foreign matter exists. The thrust bearing case part on the side in contact with the rotary operation body and the rotary operation body itself rotate as the clutch is engaged, causing a flow of hydraulic oil in the mission case in the space. , There is an advantage that the foreign matter accumulated in the space easily flows out of the space.

[Solution 5]
Another technical means of the present invention taken to solve the above-described problem is that the rotary operation body is spring-biased toward a return side opposite to a pushing direction of the piston member toward the most projecting position. A circumferential groove portion formed on a peripheral surface of a shaft portion that contacts the rotational operation body and defines a limit of operation of the rotational operation body toward the return side of the rotational operation body. The abutment surface of the retaining ring with respect to the rotary operation body causes the component force of the spring biasing force acting on the rotational operation body to be directed toward the diameter reduction direction of the retaining ring. That is, it is formed on an inclined surface.

[Operation and effect of invention according to Solution 5]
According to the invention relating to the solution means 5 described above, when the retaining ring that stops the movement of the rotating operation body pressed and urged in one direction by the compression spring in the urging direction is provided, An inclined surface is provided at the contact point, and a part of the urging force of the compression spring can be used for stable support of the retaining ring.
That is, when the rotary operation body comes into contact with the inclined surface of the retaining ring, the urging force of the compression spring acts as a component force in two directions, rightward and downward. Of these, the downward component force is directed in the direction of pushing the retaining ring toward the back side of the circumferential groove portion, and acts to reduce the diameter of the retaining ring.
Thereby, there is an advantage that the possibility of the retaining ring coming out from the circumferential groove portion can be reduced with a simple structure using the inclined surface.

It is a right view of a normal combine. It is a hydraulic circuit diagram which shows a hydraulic system. It is a front view which shows a hydrostatic continuously variable transmission and a transmission. It is the partially broken front view of a hydrostatic continuously variable transmission, and the longitudinal cross-sectional front view of a transmission. It is a vertical front view of the upper part side in a transmission. It is a vertical left side view of a transmission. It is a longitudinal front view, such as a side clutch brake unit, in a transmission. It is an enlarged vertical front view of a side clutch brake unit portion. It is an enlarged vertical front view of a side clutch brake unit portion. An oil chamber and a press piston are shown, (a) is a reciprocating operation direction of the press piston, and is an explanatory view seen from the open end side of the oil chamber, and (b) is an explanation in a sectional view taken along line Xb-Xb in FIG. FIG. It is explanatory drawing which shows the action state of a retaining ring part. The oil chamber and press piston in another embodiment are shown, (a) is a reciprocating operation direction of a press piston, and is explanatory drawing seen from the open end side of an oil chamber, (b) is a XIIb-XIIb line section in Drawing 12 (a). It is explanatory drawing in view. It is explanatory drawing which shows the action state of the retaining ring part in another embodiment.

  An example of an embodiment for carrying out the present invention will be described based on the drawings.

[Overall structure of the combine]
FIG. 1 shows the entirety of a normal combine (an all-purpose combine) that is an example of a work vehicle to which a transmission 4 according to the present invention is applied.
This normal combine is provided with a self-propelled machine A that travels with a pair of left and right crawler travel devices 1. The self-propelled aircraft A is provided with a driving unit B and a cutting processing device C (corresponding to a cutting unit) at the front position. And in the rear position of the self-propelled machine A, a full culling type threshing device D into which the cereals harvested by the reaping processing device C are sent, and a grain tank E (which stores the grains supplied from the threshing device D) And an unloader F for discharging the grains stored in the Glen tank E to the outside of the machine. In addition, a fuel tank 17 is provided on the body frame 10 at a location corresponding to the rear end portion of the self-propelled aircraft A and between the grain tank E and the threshing device D.

Then, the hydrostatic continuously variable transmission 30 that transmits the power transmitted from the output shaft (not shown) of the engine 3 to the left and right crawler travel devices 1, 1 at the front left and right central portions of the body frame 10. (Hereinafter referred to as HST) and a transmission 4 (corresponding to a transmission device) are provided.
As shown in FIGS. 3 and 4, a transmission that transmits the driving force of the engine 3 is provided between an output pulley (not shown) provided on the output shaft of the engine 3 and an input pulley 38 a of the input shaft 38 of the HST 30. A belt 37 is stretched over. The input case 39 that supports the input shaft 38 and the input pulley 38a is connected and fixed to the transmission case 35 of the HST 30 at the end opposite to the side on which the input pulley 38a exists, and the intermediate portion of the input shaft 38 in the longitudinal direction. Is fixed to the upper part of the transmission case 40 of the transmission 4.

[Operation section]
The engine 3 mounted on the body frame 10 is located below the driver seat 2 of the driver B, and the upper side of the engine 3 is covered with a box-shaped engine cover 11. The driver seat 2 is provided on the upper surface of the engine cover 11, and the engine cover 11 is used as a support for the driver seat 2.
The engine cover 11 is formed with an intake case 11A on the outer side, and an intake portion 11B is provided on the outer surface side of the intake case 11A.

A control tower 12 is erected on the front side of the driver's seat 2, and an operation tool that performs steering control of the self-propelled aircraft A on the upper surface side of the control tower 12, and an operation tool that performs lifting control of the cutting processing device C, An operating lever 13 that also serves as a pivot is provided so as to be swingable forward and backward and left and right.
As shown in FIG. 1, the left side of the driver seat 2 is provided with a side panel 14 extending from the left lateral end position of the control tower 12 toward the rear side. A main speed change lever 15 and a sub speed change lever 16 are provided on the upper surface of the front end portion of the side panel 14 as speed change operating tools for controlling the travel speed of the self-propelled machine body A.

  Further, a discharge clutch lever (not shown) is provided on the side panel 14. The discharge clutch lever performs an on / off operation of the discharge clutch G (see FIG. 1) for intermittently driving the driving force from the engine 3 with respect to the bottom screw 21 of the glen tank E to enable the grain discharge by the unloader F. And an operation tool for switching operation to a state where grain discharge is stopped.

[Reaping processing device]
The cutting processing device C is configured to scrape the tip side of the planted culm by rotating the reel 5 and to cut the stock of the culm with the cutter 6. The harvested cereals (reached cereals) are laterally fed by the lateral feed auger 7 and collected near the entrance of the feeder 8. The whole rice cake is fed backward by the feeder 8 and fed into the threshing device D.
Further, the cutting processing device C is configured to be swingable up and down with a feeder drive shaft (not shown) provided on the rear end side of the feeder 8 as a fulcrum. The feeder 8 is swung up and down by an actuator 18 such as a hydraulic cylinder provided over the body frame 10 and the lower part of the feeder 8. By setting the amount of rocking by the operation of this actuator 18, the cutting height of the cereal can be adjusted.

  The scraping reel 5 provided at an upper position on the front end side of the feeder 8 swings up and down on the front side around a swinging fulcrum (not shown) on the rear end side, so that the scraping height position with respect to the feeder 8 is reached. It is configured to be changeable. In this way, by changing the relative height of the scraping reel 5 with respect to the feeder 8, the scraping height with respect to the crop to be harvested such as the planted cereal can be changed without changing the cutting height. The change of the height position of the scraping reel 5 is performed by an expansion / contraction operation of a reel lifting / lowering device (not shown) composed of a hydraulic cylinder interposed between the upper portion of the feeder 8. The raising / lowering operation by the reel raising / lowering device is performed by a command from an operation input unit such as a push button switch (not shown) provided in the grip portion of the operation lever 13.

[Threshing equipment]
The threshing device D is an axial flow type barrel (not shown) that is driven and rotated around the axis of the posture along the front-rear direction of the self-propelled machine body A so as to perform the handling process of the harvested cereal grains supplied to the handling room. And a sorting device (not shown) for sorting the grains from the processed product obtained by the handling process.
In this sorting processing apparatus, among the sorted grains, the first thing is supplied to the grain tank E by the cerealing device 9, and the second thing is the handling chamber in which the barrel is turned by the second reducing device 19 (see FIG. (Not shown), and scraps other than the grains fall from the rear part of the sorting apparatus to the rear of the self-propelled aircraft A.

[Glen tank]
The Glen tank E includes a tank body 20 for storing the grains supplied from the cerealing device 9.
The tank body 20 is stored in the self-propelled airframe A and includes a front wall 20a facing the front side of the airframe, a rear wall 20b facing the rear side of the airframe, and left and right lateral walls 20c. Is formed. In addition, the tank body 20 has a working posture (posture shown by a solid line in FIG. 2) stored in the self-propelled aircraft A by turning around the vertical axis Y in a vertical posture at the rear position of the self-propelled aircraft A, It is supported in an inspection posture (posture indicated by a virtual line in FIG. 2) projecting laterally from the runner A so that the posture can be switched.
The vertical axis Y serving as the turning center of the Glen tank E is configured to coincide with the cylinder axis of the vertical transfer cylinder 23 provided in the unloader F provided on the rear surface side of the tank body 20.

As shown in FIGS. 1 to 4, the Glen tank E includes a bottom screw 21 that feeds grains stored in the tank main body 20 toward the rear at the bottom of the tank main body 20.
Most of the bottom wall of the tank body 20 has the grain supplied from the cerealing device 9 to the center side of the bottom in the left-right direction of the tank body 20 in the working posture in which the tank body 20 is housed in the self-propelled machine A. In order to be collected, it is formed on a tapered inclined surface that becomes lower toward the center side in the left-right direction. Due to such a structure, the bottom screw 21 is disposed at a substantially central position in the left-right direction of the tank body 20.

The bottom screw 21 has a front end of a screw shaft 21 </ b> A protruding forward of the front wall 20 a of the tank body 20. The driving force from the engine 3 is intermittently transmitted via the discharge clutch G (see FIG. 1) provided on the transmission upper side so that the driving force from the engine 3 is transmitted to the front end of the screw shaft 21A. It is configured to be possible.
The rear wall 20b of the tank body 20 is provided with a discharge cylinder portion 22 for feeding the grain sent from the bottom screw 21 to the unloader F so as to protrude rearward. The discharge cylinder portion 22 is bent upward at the rear end side, and the lower end side of the vertical transfer cylinder 23 of the unloader F is connected to the upward end surface thereof.
A bevel gear (not shown) provided at the rear end of the screw shaft 21A of the bottom screw 21 is meshed with a bevel gear (not shown) at the lower end of the vertical screw shaft 23A provided inside the vertical conveying cylinder 23. To transmit power. Thereby, it will be in the state from which the grain is carried out from the bottom screw 21 to the vertical conveyance cylinder 23 side of the unloader F.

[Unloader]
The unloader F includes a straight tubular vertical transport cylinder 23 erected upward and a horizontal transport cylinder 24 connected to the upper end of the vertical transport cylinder 23. The horizontal transfer cylinder 24 is configured to be able to swing left and right around the vertical axis Y together with the vertical transfer cylinder 23 and to swing up and down around the horizontal horizontal axis X.
The vertical conveying cylinder 23 includes the vertical screw shaft 23A therein, and constitutes an upward vertical conveying path for ascending and conveying the grain fed from the rear end portion of the bottom screw 21. The horizontal transfer cylinder 24 connected to the upper end of the vertical transfer cylinder 23 has a horizontal screw shaft 24A inside, and the grains inherited from the upper end of the vertical transfer cylinder 23 are external to the machine body in the horizontal direction. A sideways conveyance path for conveying toward the side is configured.

The unloader F is connected so that the vertical conveyance cylinder 23 can turn around the vertical axis Y along the cylinder axis of the vertical conveyance cylinder 23 with respect to the discharge cylinder portion 22 of the Glen tank E. Then, the turning operation around the vertical axis Y of the vertical transfer cylinder 23 is performed by the turning drive mechanism 26. The turning drive mechanism 26 is configured to drive a turning gear portion (not shown) provided on the outer periphery of the lower end portion of the vertical conveying cylinder 23 with a pinion gear of an electric motor (not shown).
Further, the swinging movement of the horizontal transfer cylinder 24 around the horizontal horizontal axis X is performed by the expansion and contraction operation of the hydraulic cylinder 25 provided between the upper part of the vertical transfer cylinder 23.

[Hydraulic drive system]
A hydraulic drive system for performing the raising / lowering operation, the traveling speed change, and the steering operation of the cutting processing device C will be described.
As shown in FIG. 2, the cutting processing device C is configured to move up and down by the operation of a hydraulic control unit 27 for lifting and lowering. The oil stored in the oil tank 28 is supplied to the hydraulic control unit 27 by the operation of the first hydraulic pump 29. The hydraulic control unit 27 includes an actuator 18 such as the hydraulic cylinder installed over the body frame 10 and the feeder 8, and a lift valve unit (not shown) for changing the operation pressure applied to the actuator 18. Yes.

  The raising / lowering valve unit is linked to the operating lever 13 via a raising / lowering mechanical linkage mechanism (not shown). Then, based on the swinging operation of the operation lever 13 in the front-rear direction, the operation pressure on the actuator 18 is changed by controlling the oil flow among the oil tank 28, the first hydraulic pump 29, and the lifting cylinder. It is configured as follows. From this configuration, by swinging the operation lever 13 back and forth, the harvesting processing device C is moved up and down to a lower work area for harvesting uncut cereals to be harvested and an upper non-work position for not harvesting. Can be made.

  The hydraulic pump 31 and the hydraulic motor 32 constituting the HST 30 are built in the speed change case 35. The transmission case 35 includes a case main body 35A that houses the hydraulic pump 31 and the hydraulic motor 32, and a port block 35B. The pump shaft of the hydraulic pump 31 is configured as the input shaft 33 of the HST 30 and the motor shaft of the hydraulic motor 32 is configured as the output shaft 34 of the HST 30. The self-propelled airframe A is equipped with the HST 30 in a state where the input shaft 33 and the output shaft 34 are laterally oriented and in a vertically long lateral orientation in which the hydraulic motor 32 is positioned directly below the hydraulic pump 31. The hydraulic pump 31 employs an axial plunger type variable capacity pump. As the hydraulic motor 32, an axial plunger type fixed capacity motor is adopted.

The HST 30 includes a speed change operation shaft 36 for operating a pump swash plate (not shown) of the hydraulic pump 31 so as to protrude forward from the front wall of the speed change case 35. The speed change operation shaft 36 has its front end so that the operation angle of the pump swash plate is changed to an angle corresponding to the operation position of the main speed change lever 15 in conjunction with the swinging operation of the main speed change lever 15 in the front-rear direction. The linkage arm 36a provided in the section is linked to the main transmission lever 15 through a mechanical linkage mechanism 36b for main transmission.
That is, the HST 30 is mounted on the self-propelled aircraft A in a state where the HST 30 is configured to function as a main transmission for traveling speed change.

As shown in FIG. 2, in the oil chamber 100 of each side clutch brake unit 48 arranged in the mission case 40, the lubricating oil stored in the mission case 40 is stored by the operation of the second hydraulic pump 102. Supplied for operation. The hydraulic oil is supplied from the second hydraulic pump 102 to the oil chamber 100 of each side clutch brake unit 48 via the steering valve unit 103.
The steering valve unit 103 is based on the switching valve 104 that switches the flow of oil to the oil chamber 100 of each side clutch brake unit 48 based on the operation of the operation lever 13 in the left-right direction, and on the operation of the operation lever 13. A variable relief valve 105 for changing the relief pressure for the oil chamber 100 of the left and right side clutch brake units 48 is provided. In this way, the steering operation of the self-propelled aircraft A is performed by the swinging operation of the operation lever 13 in the left-right direction.

〔transmission〕
Next, the configuration of the transmission 4 will be described.
As shown in FIGS. 3 to 6, the transmission 4 has a transmission case 40 made of a cast product, a left-right input shaft 44, a driven shaft 45, a side clutch shaft 46, and a constant mesh type selection gear type. A sub-transmission mechanism 47, a pair of side clutch brake units 48, a left and right transmission mechanism 49, and the like are incorporated, and the power input from the input shaft 44 is shifted and output to the travel drive shaft 50 on the lower transmission side. It is configured as follows. In the lower part of the mission case 40, the left and right traveling drive shafts 50 extending left and right corresponding to the left and right corresponding crawler traveling devices 1, and the left and right traveling drive shafts 50, which are rotatably supported in a state of being individually enclosed, are supported. A drive shaft case 51 is provided. Each transmission mechanism 49 includes a relay shaft 98 between the side clutch shaft 46 and the travel drive shaft 50, and is configured by a reduction gear transmission mechanism disposed including the relay shaft 98.

The mission case 40 is configured to include a left half case 40L and a right half case 40R that are configured to be divided right and left with a dividing plane along the vertical dividing line SL as a boundary. And by connecting the left and right half cases 40L, 40R with bolts, a device arrangement space 40S for forming the auxiliary transmission mechanism 47, the side clutch brake unit 48, etc. is formed therein, and The device arrangement space 40S also serves as a hydraulic oil storage space.
In addition, as shown in FIGS. 5 and 6, the mission case 40 has an oil supply port 41 through which hydraulic oil used in hydraulic equipment such as the side clutch brake unit 48 is returned to the upper portion of the mission case 40, An air vent hole 42 for venting air from the mission case 40 is provided. An oil supply pipe 41 a that guides hydraulic oil from the hydraulic equipment is connected to the oil supply port 41. The air vent hole 42 is provided with a plug 42a for facilitating air venting by removing the air vent hole 42 so as to prevent foreign matter from entering from the air vent hole 42.

Further, on the inner side of the mission case 40, a bowl-shaped flow-down guide plate portion 43 is provided at a location facing the lower side of the fuel filler port 41. The flow-down guide plate portion 43 is used to guide the flow downward while regulating the hydraulic oil injected from the oil supply port 41 so as not to flow into the air vent hole 42 side in a short circuit.
The flow-down guide plate portion 43 has a bowl-shaped guide surface 43a at a position facing directly below the oil supply port 41 so that the hydraulic oil injected from the oil supply port 41 does not fall directly onto the liquid surface of the device installation space 40S. It has. The guide surface 43 a is formed in an inclined shape such that the side closer to the lower side of the fuel filler port 41 is lower so that the side closer to the lower side of the fuel filler port 41 is lower than the side closer to the air vent hole 42.
The end of the guide surface 43a on the side close to the air vent hole 42 is on the inner surface of the mission case 40 so that the air vent hole 42 side and the oil supply port 41 side are isolated from each other in front of the air vent hole 42. Connected together. On the side close to the lower side of the oil supply port 41, a part of the guide surface 43 a is bent and formed in a V shape near the lower side of the oil supply port 41, so that the hydraulic oil injected onto the guide surface 43 a flows down while collecting. A mouth portion 43b is provided.

  As shown in FIG. 6, the mission case 40 has an oil suction port 40a and an internal oil passage 40b formed in a part of its front wall, and passes through an oil filter 106 connected to the internal oil passage, and then the side clutch. The hydraulic oil is supplied to the second hydraulic pump 102 for supplying the hydraulic oil to the hydraulic equipment such as the brake unit 48.

As shown in FIGS. 4 and 5, the mission case 40 has an input unit connected to an output unit provided in the port block 35 </ b> B of the HST 30 on the upper portion of the right side wall (on the left side in FIG. 4) on the boarding operation unit side. I have. The HST 30 is mounted on the upper portion of the right side wall with bolts in a state where the output portion of the port block 35B is connected to the input portion.
The input shaft 44 of the transmission 4 is spline-fitted to the output shaft 34 of the HST 30 via the cylindrical shaft 59 at the right end portion (left side in FIG. The shaft is configured to rotate integrally with the output shaft 34 around the axis.

As shown in FIGS. 5 and 6, the subtransmission mechanism 47 has a low-speed drive gear for low-speed transmission, which is least frequently used when traveling over a bridge, etc., in the upper part of the device installation space 40 </ b> S in the mission case 40. 60, a low-speed driven gear 61, a medium-speed drive gear 62 and a medium-speed driven gear 63 for medium-speed transmission, which are used relatively frequently during work travel, and a use frequency used during work travel and travel travel. A high-speed drive gear 64 and a high-speed driven gear 65 for high-speed transmission, and a shift mechanism 66 that enables the gear selection operation thereof, and the like. Is configured to be possible.
The shift mechanism 66 includes a first shifter 67 that selects either the low-speed driven gear 61 or the high-speed driven gear 65, and a second shifter 68 that selects the medium-speed driven gear 63, and any of the selected driven gears. The shift power is taken out from 61, 63, 65 and transmitted to the driven shaft 45.

The first shifter 67 and the second shifter 68 include a shift fork 69 provided with a first fork portion 69A for operating the first shifter and a second fork portion 69B for operating the second shifter. The driven gears 61, 63, and 65 are selected by sliding relative to each other and being held in position by a detent mechanism 71 for holding the position.
The shift fork 69 includes sub-shifts such as an operation arm 72 that slides the shift fork 69 in the left-right direction on the shift support shaft 70, a front-rear shift operation shaft 73 that supports the operation arm 72, and a linkage arm 77. It is linked to the auxiliary transmission lever 16 via a mechanical linkage mechanism 78 for use.

  As described above, the subtransmission mechanism 47 is provided across the input shaft 44 and the driven shaft 45 of the transmission 4 in a state where it is transmitted from the input shaft 44 of the transmission 4 to the driven shaft 45. Then, by selecting the driven gears 61, 63, 65 linked to the driven shaft 45 by the gear selection operation of the shift mechanism 66 interlocked with the operation of the auxiliary transmission lever 16, the transmission state is changed from the output shaft 34 of the HST 30. Is transmitted to the driven shaft 45 via the low-speed drive gear 60 and the low-speed driven gear 61, and is transmitted to the driven shaft 45 via the medium-speed drive gear 62 and the medium-speed driven gear 63. It is configured to function as a sub-transmission device that selectively switches between the state and the high-speed transmission state that is transmitted to the driven shaft 45 via the high-speed drive gear 64 and the high-speed driven gear 65.

As shown in FIGS. 4 to 6, the driven shaft 45 is a small-diameter output gear that functions as an output rotating body of the subtransmission mechanism 47 at a portion between the medium-speed driven gear 63 and the high-speed driven gear 65 at the center. 81 is spline-fitted so that the driven shaft 45 and the output gear 81 rotate together.
The side clutch shaft 46 is disposed in the upper and lower intermediate portions of the device arrangement space 40S in the mission case 40. A large-diameter transmission gear 82 as a transmission rotating body meshing with and interlocking with the output gear 81 is integrally rotated at the left and right intermediate positions so that the side clutch shaft 46 and the transmission gear 82 cannot be slid relative to each other. The spline is engaged. That is, the transmission structure from the driven shaft 45 to the side clutch shaft 46 is configured as a gear transmission type by the output gear 81 and the transmission gear 82, and the power after the shift by the auxiliary transmission mechanism 47 is changed from the driven shaft 45 to the side clutch shaft 46. It is configured to transmit the deceleration to the motor.

[Side clutch brake unit]
Next, the structure regarding the left and right side clutch brake units 48 in the transmission 4 will be described.

As shown in FIGS. 4 and 5, each side clutch brake unit 48 includes a meshing side clutch 83 for intermittently transmitting power from the transmission gear 82 to the corresponding crawler traveling device 1, and a corresponding crawler traveling device. And a multi-plate side brake 84 for braking.
Then, on the axis of the side clutch shaft 46, the transmission gear 82 is distributed left and right so as to be symmetrical about the transmission gear 82. The left side clutch brake unit 48 acts on the left crawler traveling device 1 via the left transmission mechanism 49 and the left traveling drive shaft 50, and the right side clutch brake unit 48 is coupled to the right transmission mechanism 49. The right crawler travel device 1 is configured to act on the right travel drive shaft 50.
The side clutch shaft 46 is a shaft corresponding to a drive shaft that transmits power transmitted from the transmission upper side to the side clutch brake unit 48.

[About side clutch]
A cylinder detachable by sliding in the axial direction of the side clutch shaft 46 with respect to the side clutch shaft 46 to which the driving force from the driven shaft 45 on the transmission upper side is transmitted via the output gear 81 and the transmission gear 82. The shaft 85 is externally fitted so as to be relatively rotatable.
A drive-side clutch body 87 (corresponding to a drive rotary body) is spline-fitted to a spline portion 46A formed near the shaft end of the side clutch shaft 46 so as to rotate integrally with the side clutch shaft 46. . A driven-side clutch body 86 (corresponding to a rotating operation body) is connected to the cylindrical shaft 85 on a first spline shaft portion 85A formed near the outer end of the cylindrical shaft 85 that is fitted on the side clutch shaft 46. Splines are fitted so as to rotate together.
The drive-side clutch body 87 and the driven-side clutch body 86 are provided with tooth portions 86A and 87A (corresponding to claw portions) on the surfaces facing each other in the axial direction of the side clutch shaft 46, respectively. A dog clutch type side clutch 83 (corresponding to a claw clutch) is configured such that the tooth portions 86A and 87A are engaged and disengaged with the movement of the driven clutch body 86 with respect to 87.

Each side clutch 83 is a compression spring 88 (corresponding to an urging means) that urges the driven side clutch body 86 toward a position where the tooth portions 86A, 87A of the driving side clutch body 87 and the driven side clutch body 86 mesh. ), A retaining ring 89 made of a C-shaped circlip for receiving the driven side clutch body 86 at the entering position, a spring receiver 90 for receiving one end portion of the compression spring 88, and the like.
Therefore, when the driven side clutch body 86 is slid to the entering position by the action of the compression spring 88, the transmission state is switched to the state where the tooth portion 86A of the driven side clutch body 86 and the tooth portion 87A of the driving side clutch body 87 are engaged. Further, by sliding to the cutting position against the action of the compression spring 88, the toothed portion 86A of the driven side clutch body 86 and the toothed portion 87A of the driving side clutch body 87 are switched to the shut-off state in which the meshing is released. It is configured as follows.

  Each cylindrical shaft 85 includes a second spline shaft portion 85B having a larger diameter than the first spline shaft portion 85A on the inner end side close to the transmission gear 82. And the level | step-difference part 85C located in the outer end of the 2nd spline shaft part 85B is comprised so that it may function as a spring receiver. Further, a circumferential groove portion 85D into which the retaining ring 89 is detachably engaged is formed at the outer end portion of the first spline shaft portion 85A.

Each driven-side clutch body 86 is provided with a spline boss portion 86B that is spline-fitted to the first spline shaft portion 85A of the cylindrical shaft 85 so as to be slidable relative to the inner peripheral portion thereof, and rotates integrally with the cylindrical shaft 85. It is configured as follows.
In the radial direction of the driven-side clutch body 86, a side clutch is provided at an intermediate position between the spline boss portion 86B on the inner peripheral side and the rim portion 86C on the outer peripheral side in the radial direction from the tooth portion 86A. A thrust bearing 80 is mounted on the laterally outer side of the machine body where the drive side clutch body 87 exists in the axial direction of the shaft 46. The thrust bearing 80 is interposed between the driven-side clutch body 86 and a pressing piston 101 (corresponding to a piston member) for pressing the driven-side clutch body 86, and exerts the pressing action of the pressing piston 101. In response, the driven clutch body 86 is pressed to the side away from the drive side clutch body 87.
The toothed portion 86A of the driven side clutch body 86 and the externally toothed portion 87A of the driving side clutch body 87 meshing with the driven side clutch body 86 are located at a radially inner side location than the mounting location of the thrust bearing 80. In a state and at a constant pitch in the circumferential direction.

  Each drive-side clutch body 87 corresponds to the side clutch shaft 46 so as to rotate integrally with the side clutch shaft 46 in a state where it can be attached and detached by sliding in the axial direction of the side clutch shaft 46 with respect to the side clutch shaft 46. Spline fitting is performed on both end portions on the shaft end side of the tube shaft 85 in a state adjacent to the tube shaft 85. Thus, each drive-side clutch body 87 is configured to function as a drive-side rotary body that rotates integrally with the transmission gear 82 via the side clutch shaft 46 in the left and right side clutches 83.

[About the side brake]
The side brake 84 includes a plurality of separator plates 95 that are externally fitted to the sliding unit 91 and integrally rotate, and a plurality of brake disks 96 that are alternately arranged in the axial direction of the side clutch shafts 46 and the side clutch shaft 46. And a brake housing 94 that supports a plurality of brake disks 96 and a single pressure plate 97 in a non-rotating state.

The sliding unit 91 includes spline bosses 92 that are externally fitted to the second spline shaft portion 85 </ b> B so as to rotate integrally with the cylindrical shaft 85 on both the left and right sides of the transmission gear 82. Each spline boss 92 functions as a drive gear portion 92A at the inner left and right central sides in the mission case 40, and functions as a brake hub portion 92B at the outer end located at the left and right end sides in the mission case 40. It is configured as a dual-purpose part. A thrust collar (not shown) that receives a force acting in the axial direction of the side clutch shaft 46 between the transmission gear 82 and the left and right sliding units 91 on the side clutch shaft 46 is interposed. Disguise.
The spline boss 92, the cylinder shaft 85, the driven side clutch body 86, the compression spring 88, the retaining ring 89, and the spring receiver 90 are slidably integrated with the side clutch shaft 46 in the axial direction of the side clutch shaft 46. A moving sliding unit 91 is configured.

  The brake housing 94 has a substantially cylindrical shape that surrounds the separator plate 95, the brake disc 96, and the like, and is integrally formed at the upper and lower intermediate portions of the left and right side walls of the transmission case 40. A plurality of brake discs 96 and a single pressure plate 97 are supported in a non-rotatable manner while being slidable in the axial direction of the side clutch shaft 46. In addition, a receiving portion 94A for receiving a separator plate 95 and a brake disc 96 that slides inward of the transmission case 40 along the axis of the side clutch shaft 46 is provided at the inner end portions thereof.

    The rim portion 86 </ b> C of each driven side clutch body 86 is configured to function as a pressing portion that acts on the separator plate 95 and the brake disk 96 of the corresponding side brake 84. As a result, each side brake 84 slides from the cut position described above to the braking position located in the direction opposite to the entry position, against the action of the compression spring 88 by the corresponding driven clutch body 86. Accordingly, the plurality of separator plates 95 and the brake disc 96 are pressed against each other by the pressing action of the rim portion 86C from the brake release state in which the pressure contacts due to the pressing action of the rim portion 86C are released. Switch to the braking state. As the compression spring 88 slides from the braking position to the cutting position, the braking state is switched to the braking release state.

[Clutch brake operation structure]
The pressing piston 101 for pressing the driven clutch body 86 is configured as follows.
The sliding unit 91 is mounted on the side clutch shaft 46 in a state where the driven clutch body 86 faces the oil chamber 100 (corresponding to the cylinder chamber) which is an annular cylinder space provided in the transmission case 40. Yes. An annular pressure piston 101 that slides the driven clutch body 86 is fitted into the oil chamber 100 so as to be slidable in the axial direction of the side clutch shaft 46. Thus, both the pressing piston 101 and the oil chamber 100 are formed in an annular shape (corresponding to a hollow cylindrical shape).

The pressing piston 101 slides in the axial direction of the side clutch shaft 46 by the operation of the steering valve unit 103, and this sliding causes the corresponding driven clutch body 86 to slide in the axial direction of the side clutch shaft 46. It is configured to be operated dynamically. Specifically, as the oil chamber 100 is increased by the operation of the valve unit 103, the oil chamber 100 slides along the axial center of the side clutch shaft 46 toward the center side of the side clutch shaft 46. The side clutch body 86 is slid from the clutch engaged position to the clutch disengaged position against the action of the compression spring 88, and then slid from the clutch disengaged position to the brake position.
Further, as the oil chamber 100 is depressurized by the operation of the valve unit 103, it slides along the axial center of the side clutch shaft 46 toward the shaft end side of the side clutch shaft 46, and this sliding causes the corresponding driven clutch. The body 86 is slid from the braking position to the clutch disengagement position by the action of the compression spring 88, and then is slid from the clutch disengagement position to the clutch engagement position.

  The steering valve unit 103 is linked to the operating lever 13 via the steering mechanical linkage mechanism 79 so that the operating state is switched based on the swinging operation of the operating lever 13 in the left-right direction. Specifically, in a state where the operation lever 13 is positioned at the neutral position, a reduced pressure state in which the operation pressure with respect to each pressing piston 101 is reduced is maintained. When the operation lever 13 is swung to the left from the neutral position, the operation is switched from the reduced pressure state to the left pressure increasing state in which the operation pressure applied to the left pressing piston 101 is increased. When the operation lever 13 is swung to the right from the neutral position, the pressure is switched from the reduced pressure state to the right pressure increasing state in which the operation pressure on the right pressing piston 101 is increased. When the operation lever 13 is swung to the neutral position, the left pressure increasing state or the right pressure increasing state is switched to the pressure reducing state.

  With this configuration, by holding the operating lever 13 in the neutral position, the steering valve unit 103 can be maintained in a reduced pressure state, whereby each driven clutch body 86 can be maintained in the engaged position. . As a result, the traveling state can be maintained in a straight traveling state in which the left and right crawler traveling devices 1 are driven at a constant speed. Further, by swinging the operation lever 13 to the left from the neutral position, the steering valve unit 103 can be switched from the pressure-reduced state to the left pressure-raised state, whereby the right driven clutch body 86 is engaged. While maintaining the position, the left driven clutch body 86 can be slid from the entry position to the cut position or the braking position. As a result, the traveling state can be switched from the straight traveling state to the left turning state in which the left crawler traveling device 1 is driven or braked to turn the vehicle body leftward.

  Conversely, by swinging the operation lever 13 to the right from the neutral position, the steering valve unit 103 can be switched from the pressure-reduced state to the right pressure-raised state, whereby the left-side driven clutch body 86 is moved. While maintaining the engaged position, the right driven clutch body 86 can be slid from the entered position to the cut position or the braking position. As a result, the traveling state can be switched from the straight traveling state to the right turning state in which the right crawler traveling device 1 is driven or braked to turn the vehicle body in the right direction. Then, by swinging the operation lever 13 to the neutral position in the left turn state or the right turn state, the steering valve unit 103 can be switched from the left boosted state or the right boosted state to the reduced pressure state. Thus, either the left or right driven clutch body 86 located at the cut position or the braking position can be slid to the entry position. As a result, the traveling state can be switched from the left turning state or the right turning state to the straight traveling state.

[Piston member structure]
The pressing piston 101 for pressing the driven clutch body 86 is configured as follows.
As shown in FIGS. 7 to 9, the pressing piston 101 that presses the driven clutch body 86 from the laterally outward side to the laterally inward side of the self-propelled aircraft A is formed on the case inner wall side of the transmission case 40. Further, the laterally outward side of the oil chamber 100 is inserted into the oil chamber 100, and the end facing the laterally inward side is configured to press the driven side clutch body 86 laterally inward via the thrust bearing 80.

Similar to the annular oil chamber 100, the pressing piston 101 inserted into the oil chamber 100 is formed in an annular shape concentric with the axis of the side clutch shaft 46, and the driven side clutch body 86 and the thrust bearing 80 are also formed. It is formed in a concentric ring.
The compression spring 88 for operating the pressing piston 101 to the return side is constituted by a coil spring that is externally mounted on a cylindrical shaft 85 that is externally fitted to the side clutch shaft 46. The laterally outer end of the compression spring 88 is disposed so as to contact almost the entire circumference of the surface of the driven clutch body 86 opposite to the side on which the pressing piston 101 contacts. Yes.

As shown in FIGS. 7 to 9 and FIGS. 10A and 10B, the pressing piston 101 is a part of an inner peripheral surface 101a (corresponding to an inward peripheral surface) of the annular pressing piston 101. In addition, an upward concave portion 101c is formed.
That is, the annular pressing piston 101 has an inner peripheral surface 101a at the end portion on the laterally inner side that is a portion having a larger diameter than the inner peripheral surface 101a at the end portion on the laterally outward side by the step d1. The inner peripheral surface 101a that is formed and has a diameter that is larger by the level difference d1 constitutes an upward concave portion 101c at the lower part of the annular pressing piston 101.
The outer peripheral surface 101b (corresponding to the outward peripheral surface) of the pressing piston 101 is slidable in a state of sliding contact with the inward outer peripheral surface 100b (corresponding to the inward peripheral surface) of the oil chamber 100. As shown, it is formed on a flat peripheral surface in the left-right direction (extension / retraction operation direction).

In the pressing piston 101 provided with the upward concave portion 101c as described above, as shown in FIG. 10A, the upward concave portion 101c in the lower portion of the annular pressing piston 101 and the upward concave portion 101c are opposed to each other. A space s <b> 1 having a vertical width corresponding to the above-described step d <b> 1 is generated between the inner circumferential surface 100 a of the oil chamber 100, which is a downward surface at the position.
Due to the existence of this space s1, as shown in FIGS. 8, 9, and 10, the foreign matter C1 and the like accumulated on the upward concave portion 101c remains on the upper side of the concave portion 101c, and the sliding of the pressing piston 101 is continued. Even if the operation is performed, the possibility that the foreign matter C1 and the like are drawn into the sliding contact surface between the inner peripheral surface 100a of the oil chamber 100 and the inner peripheral surface 101a of the pressing piston 101 with the sliding operation is small. That's it.

As shown in FIG. 8 or as indicated by an imaginary line in FIG. 10A, the upward concave portion 101c is laterally inward by a predetermined amount L1 from the oil chamber 100 when the pressing piston 101 is at the most projecting position. It is formed so as to exist only on the inner peripheral surface 101a in the range protruding to the side. It is not formed on the inner peripheral surface 101a of the pressing piston 101 in a range that enters the oil chamber 100 at the most protruding position.
Therefore, the expansion / contraction stroke L2 of the pressing piston 101 extends from the most retracted position shown by a solid line in FIGS. 9 and 10A to the most protruded position shown by an imaginary line in FIGS. 8 and 10A. In the operating range, the range in which the upward recessed portion 101 c is formed in the pressing piston 101 is moved out and out of the oil chamber 100. However, the laterally outward portion of the pressing piston 101 outside the range where the upward concave portion 101c is formed is reciprocated only within the oil chamber 100 and is not exposed from the oil chamber 100 to the laterally inward side. It is configured.

As shown in FIG. 7 to FIG. 9 and FIG. 10, the upward concave portion 101c is located below the portion where the tooth portion 86A of the driven side clutch body 86 and the tooth portion 87A of the driving side clutch body 87 are engaged with each other. doing. In this position, when the tooth portions 86A and 87A start to engage with each other or start to separate, foreign matter C1 such as wear powder generated by sliding contact with each other, as shown by a solid line in FIG. It is easy to deposit near the lowest point of the upward concave portion 101c curved in an arc shape. However, since the accumulated foreign matter C1 is positioned below the sliding contact surface between the inner peripheral surface 100a and the inner peripheral surface 101a of the pressing piston 101, the foreign matter C1 may be drawn into the sliding contact surface. There are few.
If such an upward recess 101c does not exist, the foreign object C1 slides between the inner peripheral surface 100a and the inner peripheral surface 101a of the pressing piston 101 as shown by a virtual line in FIG. Therefore, the foreign object C1 may be easily drawn into the sliding contact surface.

Further, as shown in FIGS. 7 and 9, the upward concave portion 101 c is formed in the oil chamber 100 in the clutch-engaged state in which the tooth portion 86 </ b> A of the driven-side clutch body 86 and the tooth portion 87 </ b> A of the driving-side clutch body 87 are engaged with each other. It is located so as to get inside.
The space s1 between the upward concave portion 101c and the downward surface of the inner peripheral surface 100a is open near the opening side of the oil chamber 100 and the lateral inward side of the pressing piston 101, and is open. A thrust bearing 80 exists near the end.
Therefore, in the clutch-engaged state in which the tooth portion 86A of the driven-side clutch body 86 and the tooth portion 87A of the driving-side clutch body 87 mesh with each other, the case portion on the side that contacts the driven-side clutch body 86 of the thrust bearing 80 is the driven-side clutch. It rotates as the body 86 rotates. Thus, the case portion of the thrust bearing 80 located on the open side of the space s1 on the side in contact with the driven side clutch body 86 and the driven side clutch body 86 itself are rotating, so that the mission case 40 is rotated. A flow in the space s1 is generated in the hydraulic oil in the inside, and the foreign matter C1 accumulated in the space s1 easily flows out of the space s1.
Then, the laterally outer portion of the inner peripheral surface 101 a of the pressing piston 101 outside the range where the upward concave portion 101 c is formed is reciprocated only within the oil chamber 100 and exposed from the oil chamber 100. Therefore, there is no possibility that foreign matter C1 accumulates on the laterally outer side portion of the inner peripheral surface 101a of the pressing piston 101 outside the range where the upward concave portion 101c is formed.

[Arrangement of sealing material]
As shown in FIGS. 7 to 9, the oil chamber 100 in which the pressing piston 101 is slidably reciprocated is provided with an escape groove 107 for determining the most protruding position of the pressing piston 101, and the pressing piston 101 and the oil chamber 100. A sealing mechanism 108 is provided for suppressing the intrusion of external foreign matter between the inner surface and the inner surface.
The escape groove 107 is constituted by an annular groove that opens on the outer peripheral surface 100 b of the oil chamber 100. Therefore, in a state where the pressing piston 101 is present at the most retracted position side, the escape groove 107 is closed by the pressing piston 101, but the pressing piston 101 moves laterally inward and laterally outward. When the end on the side reaches the location where the escape groove 107 exists, the pressurized oil in the oil chamber 100 is discharged to the outside of the chamber, and the pressing piston 101 stops moving further to the lateral inward side. This position is the most protruding position of the pressing piston 101.

On the inner surface of the oil chamber 100, the seal mechanism 108 is located at a position laterally inward from the escape groove 107 and closer to the laterally outward side than the laterally inner end of the outer peripheral surface 100 b of the oil chamber 100. Is provided.
The sealing mechanism 108 includes two sealing members 108 a disposed on the inner peripheral surface 100 a of the oil chamber 100 at a predetermined interval in the left-right direction, and one disposed on the outer peripheral surface 100 b of the oil chamber 100. The sealing material 108b is provided. One seal material 108b disposed on the outer peripheral surface 100b of the oil chamber 100 is provided so as to be positioned in the middle of the two seal materials 108a disposed on the inner peripheral surface 100a in the left-right direction. is there.

  As a result, two sealing materials 108a disposed on the inner peripheral surface 100a of the oil chamber 100 at a predetermined interval in the left-right direction and one sealing material disposed on the outer peripheral surface 100b of the oil chamber 100. 108b is displaced forward and backward in the reciprocating operation direction of the pressing piston 101, and another sealing material 108b is located between the two sealing materials 108a, and a longitudinal sectional view along the left-right direction is provided. Then, they are arranged in a substantially triangular shape.

Providing the seal mechanism 108 in this way has the following advantages.
In other words, the two pistons 108a are disposed on the inner peripheral surface 100a at a predetermined interval in the left-right direction, so that the pressing piston 101 is pushed out by the sealant 108a located on the inner back side of the oil chamber 100. The leakage of the pressure oil at the time is suppressed, and the entry of the foreign matter C1 can be suppressed by the sealing material 108a located on the open end side of the oil chamber 100.
In addition, a single sealing material 108b is disposed on the outer peripheral surface 100b of the oil chamber 100 instead of two. This is because it is considered that there is no risk of foreign matter C1 entering between the outer peripheral surface 100b and the peripheral surface of the pressing piston 101, and only a device for suppressing pressure oil leakage is provided. Can be simplified.

  Further, the sealing mechanism 108 has a triangular shape including two sealing materials 108a disposed on the inner peripheral surface 100a side of the oil chamber 100 and one sealing material 108b disposed on the outer peripheral surface 100b side. Since it arrange | positions and supports the press piston 101, it is easy to stabilize the attitude | position of the press piston 101. FIG. That is, as compared with a structure in which one sealing member 108a, 108b is provided on each of the inner peripheral surface 100a side and the outer peripheral surface 100b side and the pressing piston 101 is supported at two points, the pressing piston 101 is compared. It is easy to stably support the posture at three points.

[Structure of retaining ring]
As shown in FIG. 11, a retaining ring 89 made of a C-shaped circlip that receives the driven-side clutch body 86 at the entrance position has an inclined surface 89a (corresponding to an inclined surface) at the contact point with the driven-side clutch body 86. Yes).
In this structure, the driven clutch body 86 that is slidably fitted on the cylinder shaft 85 receives the urging force f0 of the compression spring 88 and is pressed rightward in the drawing. When the driven clutch body 86 abuts against the inclined surface 89a of the retaining ring 89, the urging force f0 of the compression spring acts as component forces f1 and f2 in two directions, rightward and downward.
The component force f1 in the right direction is an action force for operating the driven side clutch body 86 to return to the clutch engagement side, but the component force f2 in the downward direction pushes the retaining ring 89 toward the back side of the circumferential groove portion 85D. Acting in the direction and acting to reduce the diameter of the retaining ring 89.

Therefore, for example, a structure that does not include the inclined surface 89a as described above and stops the movement of the driven clutch body 86 with a retaining ring 89 having a surface perpendicular to the biasing direction of the compression spring is employed. This is advantageous in that it is easy to avoid the retaining ring 89 from falling off. That is, the driven clutch body 86 is shocked by the urging force of the compression spring 88 toward the right in the drawing, which is the axial direction of the cylindrical shaft 85, with respect to the retaining ring 89 held by the circumferential groove portion 85D. In addition, the state of frequent contact is likely to be repeated. For this reason, the width of the circumferential groove portion 85D may increase, or the retaining ring 89 itself may be deformed, and the retaining ring 89 may come out of the circumferential groove portion 85D.
Compared to this, in the retaining ring 89 provided with the inclined surface 89a, a part of the acting force of the compression spring 88 for returning the driven clutch body 86 to the clutch engagement side is used, and the retaining ring 89 is used for the circumferential groove portion 85D. Since it can utilize as an acting force in the direction pushed in to the back side, the possibility that the retaining ring 89 comes out from the circumferential groove portion 85D can be reduced.

[Other Embodiment 1]
In the above embodiment, the upward concave portion 101c is formed so as to exist only on the inner peripheral surface 101a that protrudes from the oil chamber 100 by the predetermined amount L1 to the lateral inward side in a state where the pressing piston 101 is at the most projecting position. Although the thing of the made structure was illustrated, it is not restricted to this structure.
For example, as indicated by a solid line in FIG. 12B, an upward concave portion is formed on the inner peripheral surface 101a projecting from the oil chamber 100 by a predetermined amount L1 to the lateral inward side when the pressing piston 101 is in the most retracted position. 101c may be formed, and the upward concave portion 101c may not be formed on the inner peripheral surface 101a of the pressing piston 101 at the portion that enters the oil chamber 100 at the most retracted position.
In this structure, when the driven clutch body 86 is driven at the most retracted position, the upper side of the upward concave portion 101c is largely opened as a whole, so that the flow of hydraulic oil when the foreign matter C1 exists is present. Easy to remove.
Other configurations may be the same as those in the above-described embodiment.

[Second embodiment]
In the above-described embodiment, the oil chamber 100 and the pressing piston 101 that are formed in an annular shape are illustrated as having the upward concave portion 101c. However, the present invention is not limited to this.
For example, as shown in FIG. 12 (a), the oil chamber 100 and the pressing piston 101 are formed in a round hole shape or a round bar shape, and a part of the upper side of the round bar-shaped pressing piston 101 is cut away so that an upward concave portion 101c is formed. You may comprise so that it may be provided.
Note that the structure in which the oil chamber 100 and the pressing piston 101 are formed in a round hole shape or a round bar shape is configured such that the pressing piston 101 enters the oil chamber 100 in the state of being in the most retracted position. Of course, you may do.
Other configurations may be the same as those in the above-described embodiment.

[3 of another embodiment]
In the above-described embodiment, a structure in which the retaining ring 89 is mounted on the cylindrical shaft 85 side serving as the support shaft and the movement of the driven-side clutch body 86 that is externally fitted to the cylindrical shaft 85 is exemplified. However, it is not limited to this.
For example, as shown in FIG. 13, a circumferential groove portion 85D is provided for a member that is externally fitted to the support shaft portion, and a retaining ring 89 serving as a hole circlip is attached to the circumferential groove portion 85D. An inclined surface 89 a is formed with respect to the retaining ring 89.
The components f1 and f2 of the urging force f0 of the compression spring 88 are brought into contact with the member pushed by the compression spring 88 so that the urging direction of the compression spring 88 extends in the radial direction of the retaining ring 89. It is comprised so that it may act on the orthogonal direction which faces to the side. As a result, the component force f2 in the orthogonal direction acts to push the retaining ring 89 into the circumferential groove portion 85D.
The structure of retaining the retaining ring 89 using the inclined surface 89a of the retaining ring 89 is not limited to the structure for pressing the driven side clutch body 86, and can be applied to various mechanisms.
Other configurations may be the same as those in the above-described embodiment.

  The transmission according to the present invention is not limited to ordinary combine harvesters, various harvesting machines such as self-removing combine harvesters, carrot harvesters, corn harvesters, etc., paddy field work machines such as rice transplanters, or farm work machines. It can be applied to transmissions for various work vehicles such as construction machines.

40 Mission case 80 Thrust bearing 83 Claw clutch 85 Shaft part (cylinder shaft)
85D Circumferential groove part 86 Rotating operation body (driven clutch body)
86A Nail (tooth)
87 Drive rotating body (Drive side clutch body)
87A tooth part (87A) claw part 89 retaining ring 89a inclined surface (inclined surface)
100 Cylinder chamber (oil chamber)
100a peripheral surface 101 piston member (pressing piston)
101a peripheral surface 101c recess 108a sealing material 108b sealing material

Claims (5)

A lateral cylinder chamber that opens into the space inside the transmission case;
A piston member inserted into the cylinder chamber and supported slidably,
The piston member is inserted into the cylinder chamber, and the most retracted position set on the inner back side, and the most protruded position set closer to the opening side of the cylinder chamber than the most retracted position. Are configured to be able to reciprocate within a predetermined sliding range,
Of the places where the piston member is inserted into the cylinder chamber, the piston member is in the position retracted into the cylinder chamber at the most retracted position, and the position corresponding to the position exposed to the outside of the cylinder chamber at the most protruded position. A transmission having a recess opened upward so as to form a space between the cylinder chamber and a downward surface of the cylinder chamber. The cylinder chamber and the piston member are formed in a hollow cylindrical shape,
The inward peripheral surface of the piston member is in sliding contact with the outward peripheral surface of the cylinder chamber,
The transmission according to claim 1, wherein the recess is formed on an inward circumferential surface of the piston member. Each of the outward circumferential surface and the inward circumferential surface in the cylinder chamber is provided with a seal material that is in sliding contact with the opposed circumferential surface of the piston member,
Among the sealing materials, the sealing material provided near the opening of the cylinder chamber is composed of a plurality of sealing materials provided on the outer circumferential surface or the inner circumferential surface, and the outer circumferential surface or the inner circumferential surface. Another sealing material provided on the circumferential surface facing the surface is displaced forward and backward in the reciprocating operation direction of the piston member, and the other sealing material is positioned between the plurality of sealing materials. The transmission according to claim 2 arranged so as to. In the reciprocating operation direction of the piston member, a rotational operation body that is reciprocally movable along the reciprocating operation direction and rotatable at a position adjacent to the piston member via a thrust bearing, and the rotational operation body. A drive rotator that intermittently drives the drive force,
The rotating operation body and the driving rotating body are configured such that driving force is intermittently performed by a claw clutch provided with a claw portion formed on a mutually opposing surface,
The claw clutch enters an engaged state in which the claw portions are engaged with each other as the piston member moves toward the most retracted position, and the piston member moves as the piston member moves toward the most projected position. The transmission according to any one of claims 1 to 3, wherein the transmission is configured to be in a cut state in which the claw portions are separated from each other. The rotary operation body is spring-biased toward the return side opposite to the pushing direction of the piston member toward the most projecting position,
A retaining ring that comes into contact with the rotary operation body and defines an operating limit to the return side of the rotary operation body is engaged with a circumferential groove portion formed on a peripheral surface of a shaft portion that supports the rotary operation body. ,
A contact surface of the retaining ring with respect to the rotating operation body is formed on a surface that is inclined so that a component force of the spring biasing force acting on the rotating operation body toward the return side is directed toward the diameter reducing direction of the retaining ring. The transmission according to claim 4.

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