Hydraulic clutch and power transmission system for work vehicles equipped with this hydraulic clutch

Abstract

To efficiently cool first clutch plates and second clutch plates in a hydraulic clutch equipped with the plurality of first clutch plates locked to a clutch plate supporting portion in a clutch body and the plurality of second clutch plates locked to a clutch hub.SOLUTION: In a clutch hub 51, an oiling hole 75 is bored, which supplies a lubricant from the inside of the clutch hub 51 toward first clutch plates 58 and second clutch plates 60. Between the clutch hub 51 and a rotation center axis Z of a clutch body 50 inside the clutch hub 51, an injection port 76 injecting the lubricant into the clutch hub 51 is provided. Of an inner peripheral part of the clutch hub 51, one end side part 78 located on the side where one end portion 51a in a direction along the rotation axis Z of the clutch hub 51 with respect to an opposite part 77 opposing to the injection port 76 is located, is formed in an inclined inner peripheral surface decreasing a radius toward the one end portion 51a side.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a hydraulic clutch and a traveling power transmission device for a work vehicle provided with this hydraulic clutch.

Background Art

[0002] As shown in Patent Document 1, there is a hydraulic clutch including a clutch body, a cylindrical clutch hub (clutch plate mounting portion) located inside a cylindrical clutch plate support portion provided in the clutch body, a plurality of first clutch plates (clutch plates) engaged with the clutch plate support portion and arranged in a direction along the rotation center of the clutch body, and a plurality of second clutch plates (clutch plates) engaged with the clutch hub and arranged in the direction along the rotation center. In this hydraulic clutch, an oil supply hole (through hole) formed in the clutch hub and for feeding lubricating oil to the first clutch plate and the second clutch plate is provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of hydraulic clutch, the lubricating oil supplied inside the clutch hub is struck against the inner peripheral portion of the clutch hub by the centrifugal force imparted by the rotation of the clutch hub or the clutch body. The struck lubricating oil flows to the side of the end portion in the direction along the rotation center of the clutch hub at the inner peripheral portion. The easier the lubricating oil struck against the inner peripheral portion flows to the end portion side of the clutch hub, the more difficult it is for the lubricating oil to flow into the oil supply hole of the clutch hub, so it is difficult for the lubricating oil to reach the first clutch plate and the second clutch plate, and the first clutch plate and the second clutch plate cannot be efficiently cooled.

[0005] The present invention provides a hydraulic clutch equipped with a lubrication hole through the clutch hub that can efficiently cool the first clutch plate and the second clutch plate, and a power transmission device for a work vehicle that can switch between forward and reverse while efficiently cooling the first clutch plate and the second clutch plate. [Means for solving the problem]

[0006] The hydraulic clutch according to the present invention is The clutch comprises a clutch body, a cylindrical clutch hub located inside a cylindrical clutch plate support portion provided in the clutch body, a plurality of first clutch plates locked to the clutch plate support portion and arranged in a direction along the rotation center of the clutch body, a plurality of second clutch plates locked to the clutch hub and arranged in a direction along the rotation center, an oil supply hole provided through the clutch hub and supplying lubricating oil from inside the clutch hub to the first and second clutch plates, and an injection port for injecting lubricating oil into the inside of the clutch hub, wherein the injection port is located inside the clutch hub at a location between the clutch hub and the rotation center, and at a location inside the clutch hub opposite to the portion between both ends of the clutch hub in a direction along the rotation center, and the injection port is located on the inner circumference of the clutch hub. Located at a point radially outward from the center of rotation The one-end portion of the clutch hub, located on the side where one end is positioned relative to the opposing portion in the direction along the rotation center, is formed as an inclined inner circumferential surface with a smaller radius towards the one end; the other-end portion of the inner circumferential surface of the clutch hub, located on the side where the other end is positioned relative to the opposing portion in the direction along the rotation center, is formed as an inclined inner circumferential surface with a smaller radius towards the other end; and the opposing portion is formed as a parallel inner circumferential surface parallel to the rotation center. The oil supply holes are provided at the inclined inner surface and the parallel inner surface of the clutch hub. Another hydraulic clutch according to the present invention is, The clutch comprises a clutch body, a cylindrical clutch hub located inside a cylindrical clutch plate support portion provided in the clutch body, a plurality of first clutch plates locked to the clutch plate support portion and arranged in a direction along the rotation center of the clutch body, a plurality of second clutch plates locked to the clutch hub and arranged in a direction along the rotation center, an oil supply hole provided through the clutch hub and supplying lubricating oil from inside the clutch hub to the first and second clutch plates, and an injection port for injecting lubricating oil into the inside of the clutch hub, wherein the injection port is located inside the clutch hub at a location between the clutch hub and the rotation center, and at a location inside the clutch hub opposite to the portion between both ends of the clutch hub in a direction along the rotation center, and the injection port is located on the inner circumference of the clutch hub. Located at a point radially outward from the center of rotation The one-end portion of the clutch hub, located on the side where one end is positioned relative to the opposing portion in the direction along the rotation center of the clutch hub, is formed as an inclined inner circumferential surface with a smaller radius towards the one end, and the other-end portion of the inner circumferential surface of the clutch hub, located on the side where the other end is positioned relative to the opposing portion in the direction along the rotation center of the clutch hub, is formed as an inclined inner circumferential surface with a smaller radius towards the other end, and the inclination angle of the inclined inner circumferential surface of the other-end portion is set to be gentler than the inclination angle of the inclined inner circumferential surface of the one-end portion. The oil supply hole is provided at the location of the inclined inner circumferential surface of the clutch hub, The clutch body is provided with a clutch piston for pressing and releasing the first clutch plate and the second clutch plate, a return spring for returning the clutch piston to the release position, and a stopper for receiving and supporting the return spring. The stopper is provided with an insertion portion that fits into the clutch hub, and the insertion portion is located at a point in the clutch hub that faces the other end of the internal part of the clutch hub, and where a gap is formed between the insertion portion and the other end.

[0007] In this configuration, lubricating oil is injected into the clutch hub from an injection port located midway between the clutch hub and the center of rotation, ensuring that the lubricating oil is accurately supplied to the inside of the clutch hub. The lubricating oil supplied to the inside of the clutch hub is struck against the inner circumference of the clutch hub by the centrifugal force applied by the rotation of the clutch hub and clutch body. The lubricating oil struck against the inner circumference tries to flow towards the end of the inner circumference, but since one end of the inner circumference is an inclined inner surface, the centrifugal force applied to the lubricating oil decreases as it approaches the end of the inner circumference, suppressing the flow of lubricating oil that tries to flow towards the end of the inner circumference. This makes it easier for the lubricating oil struck against the inner circumference to flow into the oil supply hole. This design allows the lubricating oil, which is precisely supplied to the inside of the clutch hub, to easily flow into the oil supply hole. As a result, a large amount of lubricating oil can be supplied from the oil supply hole to the first and second clutch plates, enabling efficient cooling of the first and second clutch plates.

[0008]

[0009] With this configuration, since the opposing portions have parallel inner surfaces, compared to the case where the opposing portions have an inclined inner surface that extends from the inclined inner surface of one end portion, the force of the flow of lubricating oil applied to the opposing portions toward the one end portion is suppressed, making it easier for the lubricating oil applied to the inner circumference of the clutch hub to flow into the oil supply hole, and thus allowing a larger amount of lubricating oil to be supplied to the first clutch plate and the second clutch plate.

[0010]

[0011] With this configuration, even if the lubricating oil applied to the inner circumference of the clutch hub is divided into one end portion and the other end portion of the inner circumference, with the lubricating oil flowing towards the end of the inner circumference from the one end portion and the other end portion, the force of the flow of the lubricating oil toward the end of the inner circumference from the one end portion and the other end portion is suppressed by the inclined inner circumferential surfaces of the one end portion and the other end portion. This makes it easier for the lubricating oil to flow into the oil supply hole, allowing a large amount of lubricating oil to be supplied to the first clutch plate and the second clutch plate.

[0012] In the present invention, Preferably, the clutch plate support portion has an oil drain hole through it that discharges lubricating oil from the inside to the outside of the clutch body.

[0013] With this configuration, the lubricating oil that has cooled the first and second clutch plates can be discharged to the outside of the clutch body through the drain hole, allowing the first and second clutch plates to be cooled by fresh lubricating oil, thus enabling efficient cooling of the first and second clutch plates.

[0014] In the present invention, Preferably, the lubrication holes are arranged at intervals in the circumferential direction of the clutch hub at each of the multiple locations along the rotation center of the clutch hub.

[0015] With this configuration, lubricating oil is supplied to the first clutch plate and the second clutch plate from multiple oil supply holes, allowing lubricating oil to be supplied to a wide area along the rotational center of the part where the first clutch plate and the second clutch plate are located, thereby efficiently cooling the first clutch plate and the second clutch plate.

[0016] In the present invention, In the case of adjacent locations among the aforementioned multiple locations, it is preferable that the oil supply hole at one adjacent location and the oil supply hole at the other adjacent location are offset in the circumferential direction of the clutch hub.

[0017] According to this configuration, the portions of the first clutch plate and the second clutch plate that supply lubricating oil from the oil supply holes located at one adjacent position and the portions of the first clutch plate and the second clutch plate that supply lubricating oil from the oil supply holes located at the other adjacent position are different in the circumferential direction of the first clutch plate and the second clutch plate. Therefore, lubricating oil can be supplied to a wide range in the circumferential direction of the first clutch plate and the second clutch plate relative to the number of oil supply holes arranged in the circumferential direction of the clutch hub at each of the plurality of locations of the clutch hub, and the first clutch plate and the second clutch plate can be efficiently cooled.

[0018] In the present invention, Inside the clutch body, a clutch piston that presses and releases the first clutch plate and the second clutch plate, a return spring that returns the clutch piston to the pressure release side, and a stopper that receives and supports the return spring are provided. The stopper is provided with an insertion portion that enters the inside of the clutch hub, and the insertion portion In the vertical wall portion extending from the center of rotation, It is preferable that the injection port is open.

[0019] According to this configuration, when providing an oil injection port at a location facing a portion between both ends in the direction along the rotation center of the clutch hub, it can be formed by utilizing the stopper in the member forming the oil injection port.

[0020] The traveling transmission device for a work vehicle according to the present invention includes a forward and reverse switching section having two hydraulic clutches configured as described above, and a transmission section that shifts the power from the power source and outputs it to the forward and reverse switching section. When one of the two hydraulic clutches in the forward and reverse switching section is switched to engage, the power from the transmission section is converted into forward power and output toward the traveling device. When the other of the two hydraulic clutches is switched to engage, the power from the transmission section is converted into reverse power and output toward the traveling device.

[0021] According to this configuration, one hydraulic clutch converts the power input from the transmission part into forward power while rotating it at high speed, and the other hydraulic clutch converts the power input from the transmission part into reverse power while rotating it at high speed. However, since a large amount of lubricating oil can be supplied to the first clutch plate and the second clutch plate in one hydraulic clutch and the other hydraulic clutch, it is possible to switch between forward and reverse while efficiently cooling the first clutch plate and the second clutch plate in one hydraulic clutch and the other hydraulic clutch.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view of the tractor. [Figure 2] It is a schematic diagram of the traveling transmission device. [Figure 3] It is a cross-sectional view of the forward clutch and the reverse clutch. [Figure 4] It is a cross-sectional view of the reverse clutch. [Figure 5] It is a plan view of the clutch hub. [Figure 6] It is a cross-sectional view of the clutch hub.

Modes for Carrying Out the Invention

[0023] Hereinafter, an embodiment which is an example of the present invention will be described based on the drawings. In the following description, regarding the traveling vehicle body of the tractor (an example of a "work vehicle"), the direction of the arrow F shown in FIG. 1 is the "front of the vehicle body", the direction of the arrow B is the "rear of the vehicle body", the direction of the arrow U is the "upper part of the vehicle body", the direction of the arrow D is the "lower part of the vehicle body", the direction on the front side of the paper surface of FIG. 1 is the "left side of the vehicle body", and the direction on the back side of the paper surface of FIG. 1 is the "right side of the vehicle body".

[0024] 〔Overall Configuration of the Tractor〕 Figure 1 shows a tractor. This tractor has a vehicle body 3 supported by a pair of steerable and drivable front wheels 1 (running gear) and a pair of drivable rear wheels 2 (running gear). A drive unit 5 containing an engine 4 is provided at the front of the vehicle body 3. At the rear of the vehicle body 3 are a driver's compartment 6 where the operator sits and operates the vehicle, and a link mechanism 7 that connects to work equipment such as a rotary tiller so that it can be raised and lowered. The driver's compartment 6 is equipped with a driver's seat 8, a steering wheel 9 for steering the front wheels 1, and a cabin 10 that covers the passenger space. The vehicle body frame 11 of the vehicle body 3 is composed of an engine 4, a transmission case 12 whose front end is connected to the rear of the engine 4, and a front wheel support frame 13 connected to the bottom of the engine 4. A power take-off shaft 14 that extracts power from the engine 4 and transmits it to the work equipment is provided at the rear of the transmission case 12.

[0025] [Power transmission system for traction] The traction power transmission device 15, which transmits power from the engine 4 to the front wheels 1 and rear wheels 2, includes, as shown in Figure 2, a gear shift unit 21 having an input shaft 20 etc. located at the front of the transmission case 12, a forward / reverse switching unit 23 located behind the gear shift unit 21, a rear wheel differential mechanism 16 located behind the forward / reverse switching unit 23, and a front wheel transmission unit 25 housed in the lower part of the transmission case 12.

[0026] As shown in Figure 2, power from the output shaft 4a of the engine 4 is transmitted to the input shaft 20 via the main clutch 19. The transmission unit 21 is equipped with a continuously variable transmission 28 to which the power from the input shaft 20 is input via the rotating shaft 26 and the gear interlocking mechanism 27, a planetary transmission 31 to which the output of the continuously variable transmission 28 is input via the gear interlocking mechanism 30 and the power from the input shaft 20 is input via the gear interlocking mechanism 29, and a stepped transmission unit 22 to which the output of the planetary transmission 31 is input.

[0027] [Continuously Variable Transmission] As shown in Figure 2, the continuously variable transmission 28 comprises a variable displacement hydraulic pump P to which power from the input shaft 20 is input via a rotating shaft 26 and a gear interlocking mechanism 27, and a hydraulic motor M driven by pressurized oil from the hydraulic pump P. By changing the swash plate angle of the hydraulic pump P, the power from the input shaft 20 is changed into forward and reverse rotational power, and the rotational speeds of the forward and reverse rotational power are continuously varied and output from the hydraulic pump P. The continuously variable transmission 28 is configured as a hydrostatic continuously variable transmission.

[0028] [Planetary gearbox] As shown in Figure 2, the planetary gearbox 31 comprises a first planetary gearbox 31a and a second planetary gearbox 31b linked to the first planetary gearbox 31a. The linkage between the first planetary gearbox 31a and the second planetary gearbox 31b is achieved by linking the planetary gears of the first planetary gearbox 31a with the planetary gears of the second planetary gearbox 31b. The planetary gearbox 31 is configured as a composite planetary gearbox. The output of the continuously variable transmission 28 is input to the sun gear of the first planetary gearbox 31a via the gear linkage mechanism 30, and the power of the input shaft 20 is input to the ring gear of the first planetary gearbox 31a via the gear linkage mechanism 29. The first output shaft 32a, the second output shaft 32b, and the third output shaft 32c extend backward from the second planetary gearbox 31b.

[0029] In the planetary transmission 31, the power input from the engine 4 to the first planetary transmission unit 31a via the input shaft 20 and gear interlocking mechanism 29, and the power input from the continuously variable transmission 28 to the first planetary transmission unit 31a via the gear interlocking mechanism 30, are combined by the first planetary transmission unit 31a and the second planetary transmission unit 31b, and the combined power is output from the first output shaft 32a, the second output shaft 32b, and the third output shaft 32c. In the planetary transmission 31, when the continuously variable transmission 28 is shifted, the combined power of the rotational speed corresponding to the shifted state of the continuously variable transmission 28 is output.

[0030] [Stepped transmission section] As shown in Figure 2, the stepped transmission unit 22 includes an output shaft 34 located parallel to the first output shaft 32a, second output shaft 32b, and third output shaft 32c of the planetary transmission 31. The output shaft 34 is equipped with a first clutch CL1, a second clutch CL2, a third clutch CL3, and a fourth clutch CL4. The first clutch CL1 and the first output shaft 32a are connected by a first gear interlocking mechanism 33a. The second clutch CL2 and the third output shaft 32c are connected by a second gear interlocking mechanism 33b. The third clutch CL3 and the second output shaft 32b are connected by a third gear interlocking mechanism 33c. The fourth clutch CL4 and the third output shaft 32c are connected by a fourth gear interlocking mechanism 33d.

[0031] In the stepped transmission unit 22, when the first clutch CL1 is switched to the engaged position, the combined power of the continuously variable transmission output from the first output shaft 32a of the planetary transmission unit 31 is output from the output shaft 34 as power that shifts continuously in the 1st gear range. When the second clutch CL2 is switched to the engaged position, the combined power of the continuously variable transmission output from the third output shaft 32c of the planetary transmission unit 31 is output from the output shaft 34 as power that shifts continuously in the 2nd gear range, which is a higher speed range than the 1st gear range. When the third clutch CL3 is switched to the engaged position, the combined power of the continuously variable transmission output from the second output shaft 32b of the planetary transmission unit 31 is output from the output shaft 34 as power that shifts continuously in the 3rd gear range, which is a higher speed range than the 2nd gear range. When the fourth clutch CL4 is engaged, the combined power of the continuously variable transmission output from the third output shaft 32c of the planetary transmission 31 is output from the output shaft 34 as power that shifts continuously in the 4th gear range, which is a higher speed range than the 3rd gear range.

[0032] [Forward / reverse switching mechanism] As shown in Figure 2, the forward / reverse switching unit 23 includes an input shaft 23a connected to the output shaft 34 of the stepped transmission unit 22, and an output shaft 23b located parallel to the input shaft 23a. The output shaft 23b is made of a cylindrical shaft and is fitted onto a rotating shaft 18 that transmits power from the rotating shaft 26 to the power take-off shaft 14. The input shaft 23a is equipped with a forward clutch CLF and a reverse clutch CLR. A forward gear interlocking mechanism 35f is provided across the forward clutch CLF and the output shaft 23b. A reverse gear interlocking mechanism 35r is provided across the reverse clutch CLR and the output shaft 23b.

[0033] In the forward / reverse switching unit 23, power from the output shaft 34 of the stepped transmission unit 22 is transmitted to the input shaft 23a. When the forward clutch CLF is engaged, the power from the input shaft 23a is converted into forward power by the forward clutch CLF and the forward gear interlocking mechanism 35f and output from the output shaft 23b. When the reverse clutch CLR is engaged, the power from the input shaft 23a is converted into reverse power by the reverse clutch CLR and the reverse gear interlocking mechanism 35r and output from the output shaft 23b.

[0034] [Rear wheel differential mechanism] As shown in Figure 2, the rear wheel differential mechanism 16 includes an input shaft 16a to which the forward and reverse power of the output shaft 23b of the forward / reverse switching section is transmitted via a gear interlocking mechanism 24, and the power of the input shaft 16a is transmitted to the left and right rear wheels 2 from the left and right output shafts 16b. The power of the left output shaft 16b is transmitted to the left rear wheel 2 via a planetary reduction mechanism 36. A steering brake 37 is provided on the left output shaft 16b. Although not shown, the transmission system from the right output shaft 16b to the right rear wheel 2 is equipped with the same planetary reduction mechanism 36 and steering brake 37 as in the transmission system to the left rear wheel 2.

[0035] [Front wheel transmission] As shown in Figure 2, the front wheel transmission unit 25 includes an input shaft 25a through which forward and reverse power from the output shaft 23b of the forward / reverse switching unit 23 is transmitted via a gear interlocking mechanism 24, and an output shaft 25b located parallel to the input shaft 25a. The input shaft 25a is equipped with a constant speed clutch CLT and a speed-increasing clutch CLH. A constant speed gear interlocking mechanism 39 is provided across the constant speed clutch CLT and the output shaft 25b. A speed-increasing gear interlocking mechanism 40 is provided across the speed-increasing clutch CLH and the output shaft 25b. A parking brake 38 is provided on the transmission shaft 24a of the gear interlocking mechanism 24.

[0036] In the front wheel transmission unit 25, when the constant-speed clutch CLT is engaged, the power from the input shaft 25a is transmitted to the output shaft 25b by the constant-speed clutch CLT and the constant-speed gear interlocking mechanism 39, and power is output from the output shaft 25b to make the peripheral speed of the front wheel 1 the same as the peripheral speed of the rear wheel 2. When the speed-increasing clutch CLH is engaged, the power from the input shaft 25a is transmitted to the output shaft 25b by the speed-increasing clutch CLH and the speed-increasing gear interlocking mechanism 40, and power is output from the output shaft 25b to make the peripheral speed of the front wheel 1 faster than the peripheral speed of the rear wheel 2. The power output from the output shaft 25b is transmitted to the front wheel differential mechanism 17 via the rotating shaft 43.

[0037] [Forward clutch, reverse clutch] As shown in Figures 3 and 4, the forward clutch CLF and the reverse clutch CLR are comprised of hydraulic clutches. The forward clutch CLF and the reverse clutch CLR include a clutch body 50 and a clutch hub 51.

[0038] The clutch body 50 includes a boss portion 50A located in the center of the clutch body 50, a cylindrical clutch plate support portion 50B located on the outer circumference of the clutch body 50, and a connecting portion 50C that connects the clutch plate support portion 50B and the boss portion 50A at one end in a direction along the rotation center Z of the clutch body 50. The connecting portion 50C of the clutch body 50 of the forward clutch CLF and the connecting portion 50C of the clutch body 50 of the reverse clutch CLR are integrally formed. The clutch body 50 of the forward clutch CLF and the clutch body 50 of the reverse clutch CLR are connected by the connecting portion 50C. The boss portion 50A is fitted onto the input shaft 23a of the forward / reverse switching portion 23. The clutch body 50 is rotatably connected to the input shaft 23a by a key 52 that engages the boss portion 50A with the input shaft 23a.

[0039] The clutch hub 51 is formed in a cylindrical shape. The clutch hub 51 is located inside the clutch plate support portion 50B. In the forward clutch CLF, one end of the clutch hub 51 is connected to the forward gear 53 in the forward gear interlocking mechanism 35f, and the clutch hub 51 is supported on the input shaft 23a via the forward gear 53 and a bearing 54. In the reverse clutch CLR, one end of the clutch hub 51 is connected to the reverse gear 55 in the reverse gear interlocking mechanism 35r, and the clutch hub 51 is supported on the input shaft 23a via the reverse gear 55 and a bearing 56. The clutch hub 51 is supported on the input shaft 23a in a manner that allows it to rotate around the rotation center Z.

[0040] Multiple clutch plates, known as first clutch plates 58, are secured to a guide portion 57 provided on the clutch plate support portion 50B, arranged in a direction along the rotation center Z. The multiple first clutch plates 58 are supported on the clutch plate support portion 50B in a manner that allows them to rotate together with the clutch plate support portion 50B and to slide guided by the guide portion 57.

[0041] Multiple second clutch plates 60, arranged in a direction along the rotation center Z, are locked to a guide portion 59 provided on the clutch hub 51. The multiple friction plates, the second clutch plates 60, are supported on the clutch hub 51 in a manner that allows them to rotate together with the clutch hub 51 and slide guided by the guide portion 59.

[0042] A clutch piston 61, a return spring 62, and a spring stopper 63 are provided inside the clutch body 50.

[0043] As shown in Figure 4, the base of the clutch plate support portion 50B is provided with a first support portion 64 that fits onto the outer circumference of the clutch piston 61, and the end of the boss portion 50A is provided with a second support portion 65 that fits onto the inner circumference of the clutch piston 61. The clutch piston 61 is supported by the first support portion 64 and the second support portion 65 in a state that allows it to slide between a clutch-engaged position, where it presses the first clutch plate 58 and the second clutch plate 60, and a clutch-disengaged position, where it releases the pressure on the first clutch plate 58 and the second clutch plate 60. When the first clutch plate 58 and the second clutch plate 60 are pressed by the clutch piston 61, they are received and supported by a clutch plate stopper 66 provided on the clutch plate support portion 50B, and the clutch plate stopper 66 is received and supported by a snap ring 67.

[0044] The return spring 62 is provided at multiple locations around the clutch piston 61, extending from the clutch piston 61 to the spring stopper 63. In this embodiment, as shown in Figure 4, the spring stopper 63 is provided with an insertion portion 63a that fits into the clutch hub 51, the clutch piston 61 is provided with a spring housing portion 61a, and the return spring 62 is provided extending from the insertion portion 63a to the spring housing portion 61a. The return spring 62 uses the spring stopper 63, which is received and supported by the snap ring 68, as a reaction force member to push the clutch piston 61 toward the connecting portion 50C, and operates the clutch piston 61 back to the clutch disengagement position, which releases the pressure on the first clutch plate 58 and the second clutch plate 60.

[0045] In the forward clutch CLF and reverse clutch CLR, the clutch body 50 is driven by the input shaft 23a. When hydraulic fluid is supplied from the operating oil passage 70 located inside the input shaft 23a to the oil chamber 72 via the connecting oil passage 71 formed in the boss portion 50A, the clutch piston 61 is slid by the hydraulic fluid against the return spring 62 to the clutch engaged position. The first clutch plate 58 and the second clutch plate 60 are pushed toward the clutch plate stopper 66 by the operating portion 61c of the clutch piston 61, and the first clutch plate 58 and the second clutch plate 60 are pressed together and connected by friction, and the clutch engages so that the power of the clutch body 50 is transmitted to the clutch hub 51 by the connection of the first clutch plate 58 and the second clutch plate 60. When the hydraulic fluid is discharged from the oil chamber 72, the clutch piston 61 is slid to the clutch disengagement position by the return spring 62, releasing the pressure between the first clutch plate 58 and the second clutch plate 60 by the clutch piston 61, disengaging the connection between the first clutch plate 58 and the second clutch plate 60, and cutting off power transmission from the clutch body 50 to the clutch hub 51, thus disengaging the clutch.

[0046] [Cooling of the first and second clutch plates] As shown in Figures 3 and 4, the clutch hub 51 is provided with oil supply holes 75 that supply lubricating oil to the first clutch plate 58 and the second clutch plate 60 from inside the clutch hub 51. As shown in Figure 5, the oil supply holes 75 are provided at multiple locations along the rotation center Z of the clutch hub 51. At each of the multiple locations along the rotation center Z, the oil supply holes 75 are arranged at equal intervals in the circumferential direction of the clutch hub 51. As shown in Figure 5, at adjacent locations along the rotation center Z, the oil supply holes 75 are arranged such that the oil supply holes 75 at one adjacent location and the oil supply holes 75 at the other adjacent location are offset in the circumferential direction of the clutch hub 51. In this embodiment, the oil supply holes 75 are provided at 10 locations along the rotation center Z of the clutch hub 51, but it is possible to provide 9 or fewer locations, or 11 or more locations along the rotation center Z of the clutch hub 51. In this embodiment, the oil supply holes 75 are provided at four locations that are equally spaced in the circumferential direction of the clutch hub 51, each of the ten locations along the rotation center Z of the clutch hub 51. However, it is possible to provide them at three or fewer locations, or five or more locations, in the circumferential direction of the clutch hub 51.

[0047] As shown in Figures 3 and 4, an injection port 76 for injecting lubricating oil into the clutch hub 51 is provided inside the clutch hub 51 at an intermediate location between the clutch hub 51 and the rotation center Z. In this embodiment, as shown in Figures 3 and 4, the spring stopper 63 is provided with a piston support portion 63b located between the clutch hub 51 and the connecting portion 50C of the clutch body 50, which slides the outer circumference 61b of the clutch piston 61 from the inside, and an insertion portion 63a extending from the end opposite to the end that supports the outer circumference 61b of the piston support portion 63b to the side opposite to the side where the connecting portion 50C is located, and entering into the clutch hub 51. The injection port 76 is opened in the insertion portion 63a of the spring stopper 63. The injection port 76 can be positioned opposite the portion between the two ends in the direction along the rotation center Z of the clutch hub 51. More specifically, as shown in Figures 3 and 4, a vertical wall portion 63c extending radially from the clutch hub 51 is provided at the end of the insertion portion 63a opposite to the side where the piston support portion 63b is located, and the injection port 76 is opened in the vertical wall portion 63c.

[0048] As shown in Figures 4 and 6, of the inner circumference of the clutch hub 51, the opposing portion 77 facing the injection port 76 is formed as a parallel inner surface parallel to the rotation center Z. Of the inner circumference of the clutch hub 51, the one-end portion 78 located on the side where one end 51a is located in the direction along the rotation center Z of the clutch hub 51 relative to the opposing portion 77 is formed as an inclined inner surface with a smaller radius towards the end 51a. Of the inner circumference of the clutch hub 51, the other-end portion 79 located on the side where the other end 51b is located in the direction along the rotation center Z of the clutch hub 51 relative to the opposing portion 77 is formed as an inclined inner surface with a smaller radius towards the other end 51b.

[0049] The inclination angle Θ1 of the other end portion 79 is set to a gentler angle than the inclination angle Θ2 of the one end portion 78. Compared to the case where the inclination angle Θ1 of the other end portion 79 is set to a steeper angle than the inclination angle Θ2 of the one end portion 78, and the case where the inclination angle Θ1 of the other end portion 79 is set to the same angle as the inclination angle Θ2 of the one end portion 78, the gap between the other end portion 79 and the insertion portion 63a of the spring stopper 63 is wider, making it easier for lubricating oil to enter between the other end portion 79 and the insertion portion 63a, and the volume between the other end portion 79 and the insertion portion 63a is larger, allowing more lubricating oil to enter between the other end portion 79 and the insertion portion 63a. In this embodiment, the inclination angle Θ1 of the other end portion 79 is set to be less steep than the inclination angle Θ2 of the one end portion 78. However, it is possible to set the inclination angle Θ1 of the other end portion 79 to be steeper than the inclination angle Θ2 of the one end portion 78, or to set the inclination angle Θ1 of the other end portion 79 to be the same angle as the inclination angle Θ2 of the one end portion 78.

[0050] As shown in Figures 3 and 4, the clutch plate support portion 50B of the clutch body 50 has drain holes 80 that pass through it to discharge lubricating oil from the inside to the outside of the clutch body 50. The drain holes 80 are provided at multiple locations in the direction along the rotation center Z of the clutch plate support portion 50B. At each of the multiple locations in the direction along the rotation center Z of the clutch plate support portion 50B, the drain holes 80 are provided at multiple locations aligned in the circumferential direction of the clutch plate support portion 50B. The drain holes 80 can be of any shape, such as oval, circular, or rectangular. In the case of large drain holes 80, they can be provided at only one location on the clutch plate support portion 50B, and the number and locations of the drain holes 80 can be any number or any number.

[0051] As shown in Figures 3 and 4, an oil reservoir chamber 81 communicating with the fill port 76 is formed by the clutch piston 61, the spring stopper 63, and the boss portion 50A. An oil supply passage 82 is provided inside the input shaft 23a, and a connecting oil passage 83 connecting the oil supply passage 82 and the oil reservoir chamber 81 is formed in the boss portion 50A.

[0052] In the forward clutch CLF and reverse clutch CLR, lubricating oil is supplied from the oil supply passage 82 to the connecting oil passage 83 and to the oil reservoir chamber 81 through the gap between the clutch piston 61 and the boss portion 50A. The lubricating oil supplied to the oil reservoir chamber 81 is then injected into the interior 84 of the clutch hub 51 from the inlet 76. The inlet 76 is located inside the clutch hub 51 between the clutch hub 51 and the rotation center Z, ensuring accurate injection of lubricating oil into the interior 84 of the clutch hub 51 from the inlet 76. The lubricating oil injected into the interior 84 is struck against the inner circumference of the clutch hub 51 by the centrifugal force applied by the rotation of the clutch body 50. The struck lubricating oil then attempts to flow from the opposing portion 77 into one end portion 78 and the other end portion 79. Since the opposing portion 77 is a parallel inner surface, compared to the case where the opposing portion 77 is an inclined inner surface that extends from the inclined inner surface of one end portion 78 and the inclined inner surface of the other end portion 79, the force of the flow of lubricating oil that is struck against the opposing portion 77 toward the one end portion 78 and the other end portion 79 is suppressed, making it easier for the lubricating oil struck against the inner surface to flow into the oil supply hole 75. Since the one end portion 78 of the inner surface is an inclined inner surface, in the one end portion 78, the centrifugal force applied to the lubricating oil is smaller as it approaches the one end portion 51a of the inner surface, and the force of the flow of lubricating oil that tries to flow toward the one end portion 51a of the inner surface is suppressed. Since the other end portion 79 of the inner surface is an inclined inner surface, in the other end portion 79, the centrifugal force applied to the lubricating oil is smaller as it approaches the other end portion 51b of the inner surface, and the force of the flow of lubricating oil that tries to flow toward the other end portion 51b of the inner surface is suppressed. As the flow of lubricating oil towards one end 51a and the other end 51b is suppressed on the inner circumference of the clutch hub 51, the lubricating oil that has been struck on the inner circumference of the clutch hub 51 can easily flow into the oil supply holes 75, and a large amount of lubricating oil is supplied to the first clutch plate 58 and the second clutch plate 60. Multiple oil supply holes 75 are opened at multiple locations in the circumferential direction of the clutch hub 51 and at multiple locations along the rotation center Z of the clutch hub 51. Furthermore, at multiple locations along the rotation center Z, the oil supply holes 75 at one adjacent location and the oil supply holes 75 at the other adjacent location are offset in the circumferential direction of the clutch hub 51, so that lubricating oil is supplied to a wide area of ​​the region where the first clutch plate 58 and the second clutch plate 60 are located.The supply of lubricating oil from the oil supply hole 75 to the first clutch plate 58 and the second clutch plate 60 is carried out while the lubricating oil that has cooled the first clutch plate 58 and the second clutch plate 60 is discharged from the oil drain hole 80. In other words, the lubricating oil that is accurately supplied to the inside 84 of the clutch hub 51 flows easily into the oil supply hole 75, supplying a large amount of lubricating oil to the first clutch plate 58 and the second clutch plate 60. Furthermore, the lubricating oil reaches a wide area of ​​the parts where the first clutch plate 58 and the second clutch plate 60 are located, and the first clutch plate 58 and the second clutch plate 60 are efficiently cooled by the lubricating oil.

[0053] [Another embodiment] (1) In the above embodiment, hydraulic clutches used as the forward clutch CLF and the reverse clutch CLR were shown as examples, but the invention is not limited to these, and hydraulic clutches used for shifting in a transmission or the like may also be used.

[0054] (2) In the above-described embodiment, an example was shown in which the clutch body 50 is the driving side and the clutch hub 51 is the driven side. However, it is also possible to configure it so that the clutch hub 51 is the driving side and the clutch body 50 is the driven side.

[0055] (3) In the above embodiment, an example was shown in which both the one-end portion 78 and the other-end portion 79 are formed on an inclined inner circumferential surface. However, it is also possible that only one of the one-end portion 78 and the other-end portion 79 is formed on an inclined inner circumferential surface. Furthermore, in the above embodiment, an example was shown in which the opposing portion 77 is located between the two ends of the inner circumferential portion. However, it is also possible that the opposing portion 77 is located at one end of the two ends of the inner circumferential portion, and only the portion of the inner circumferential portion located on the side of the one end relative to the opposing portion 77 is formed on an inclined inner circumferential surface.

[0056] (4) In the above embodiment, an example in which an oil drain hole 80 is provided is shown, but it is also possible not to provide an oil drain hole 80.

[0057] (5) In the embodiment described above, an example was shown in which oil supply holes 75 were provided at 10 locations in the direction along the rotation center Z of the clutch hub 51. However, oil supply holes 75 may be provided at 9 or fewer locations, or at 11 or more locations in the direction along the rotation center Z.

[0058] (6) In the embodiment described above, an example was shown in which oil supply holes 75 were provided at four locations in the circumferential direction of the clutch hub 51. However, oil supply holes 75 may be provided at three or fewer locations, or five or more locations, in the circumferential direction of the clutch hub 51.

[0059] (7) In the above-described embodiment, an example was shown in which the oil supply holes 75 at one adjacent location and the oil supply holes 75 at the other adjacent location are misaligned in the circumferential direction of the clutch hub 51. However, the oil supply holes 75 at one adjacent location and the oil supply holes 75 at the other adjacent location may not be misaligned in the circumferential direction of the clutch hub 51, but may be aligned in a line along the rotation center Z.

[0060] (8) In the above embodiment, an example was shown in which an injection port 76 is opened in the spring stopper 63, but the invention is not limited to this, and the opening may be in the boss portion 50A or the like.

[0061] (9) In the embodiments described above, an example was shown in which front wheels 1 and rear wheels 2 are provided, but the running gear is not limited to this, and may also be a crawler running gear or a running gear that combines wheels and mini-crawlers.

[0062] (10) In the above-described embodiment, an example in which an engine 4 is provided is shown, but the power source is not limited to an engine 4, and an electric motor may also be provided. [Industrial applicability]

[0063] The present invention can be applied to a hydraulic clutch comprising a plurality of first clutch plates locked to a clutch plate support portion of a clutch body and a plurality of second clutch plates locked to a clutch hub. [Explanation of Symbols]

[0064] 4. Engine (power source) 21 Gear shifting section 23 Forward / reverse switching section 50 Clutch body 50B Clutch plate locking part 51 Clutch Hub 51a One end 51b Other end (one end) 58 Clutch plate (first clutch plate) 60 Friction Plate (Second Clutch Plate) 61 Clutch Piston 62 Return Spring 63 Spring stopper (stopper) 63a Insertion section 75 Fuel filler hole 77 Opposite part 78 One end part 79 Other end side part (one end side part) 80 Oil drain hole CLF forward clutch (one hydraulic clutch) CLR Reverse Clutch (the other hydraulic clutch) Z-axis rotation center

Claims

1. Clutch body and A cylindrical clutch hub located inside the cylindrical clutch plate support portion provided in the clutch body, Multiple first clutch plates are locked to the clutch plate support and are arranged in a direction along the rotation center of the clutch body, Multiple second clutch plates are engaged with the clutch hub and are arranged in a direction along the center of rotation, A lubrication hole is provided through the clutch hub and supplies lubricating oil from inside the clutch hub toward the first clutch plate and the second clutch plate, The clutch hub is provided with an inlet for injecting lubricating oil, The injection port is located inside the clutch hub at a location between the clutch hub and the rotation center, and at a location inside the clutch hub facing the portion between the two ends in the direction along the rotation center of the clutch hub. Of the inner circumference of the clutch hub, the portion located on the side of the clutch hub where one end is located in the direction along the rotation center is formed as an inclined inner circumference with a smaller radius towards the end, relative to the opposing portion located radially outward from the injection port to the rotation center. Of the inner circumference of the clutch hub, the portion on the other end side, which is located on the side of the clutch hub in the direction along the center of rotation of the clutch hub relative to the opposing portion, is formed as an inclined inner circumference with a smaller radius towards the other end side. The opposing portions are formed on parallel inner surfaces parallel to the center of rotation, A hydraulic clutch in which the oil supply holes are provided at the inclined inner surface and the parallel inner surface of the clutch hub.

2. Inside the clutch body, a clutch piston is provided for pressing and releasing the first clutch plate and the second clutch plate, a return spring is provided for returning the clutch piston to the release position, and a stopper is provided for receiving and supporting the return spring. The stopper is provided with an insertion portion that fits into the inside of the clutch hub, The hydraulic clutch according to claim 1, wherein the inlet is opened in a vertical wall portion extending from the inlet portion toward the rotation center.

3. Clutch body and A cylindrical clutch hub located inside the cylindrical clutch plate support portion provided in the clutch body, Multiple first clutch plates are locked to the clutch plate support and are arranged in a direction along the rotation center of the clutch body, Multiple second clutch plates are engaged with the clutch hub and are arranged in a direction along the center of rotation, A lubrication hole is provided through the clutch hub and supplies lubricating oil from inside the clutch hub toward the first clutch plate and the second clutch plate, The clutch hub is provided with an inlet for injecting lubricating oil, The injection port is located inside the clutch hub at a location between the clutch hub and the rotation center, and at a location inside the clutch hub facing the portion between the two ends in the direction along the rotation center of the clutch hub. Of the inner circumference of the clutch hub, the portion located on the side of the clutch hub where one end is located in the direction along the rotation center is formed as an inclined inner circumference with a smaller radius towards the end, relative to the opposing portion located radially outward from the injection port to the rotation center. Of the inner circumference of the clutch hub, the portion on the other end side, which is located on the side of the clutch hub in the direction along the center of rotation of the clutch hub relative to the opposing portion, is formed as an inclined inner circumference with a smaller radius towards the other end side. The inclination angle of the inclined inner circumferential surface of the other end portion is set to be gentler than the inclination angle of the inclined inner circumferential surface of the one end portion. The oil supply hole is provided at the location of the inclined inner circumferential surface of the clutch hub, Inside the clutch body, a clutch piston is provided for pressing and releasing the first clutch plate and the second clutch plate, a return spring is provided for returning the clutch piston to the release position, and a stopper is provided for receiving and supporting the return spring. The stopper is provided with an insertion portion that fits into the inside of the clutch hub, The recessed portion is located at a point in the clutch hub that faces the other end of the internal portion of the clutch hub, and at a point where a gap is formed between the recessed portion and the other end.

4. The hydraulic clutch according to claim 3, wherein the opposing portions are formed on parallel inner circumferential surfaces parallel to the center of rotation.

5. The hydraulic clutch according to claim 1 or 3, wherein the clutch plate support portion has an oil drain hole through it for discharging lubricating oil from the inside to the outside of the clutch body.

6. The hydraulic clutch according to claim 1 or 3, wherein the oil supply holes are arranged at intervals in the circumferential direction of the clutch hub at each of a plurality of locations in the direction along the rotation center of the clutch hub.

7. The hydraulic clutch according to claim 6, wherein, at adjacent locations of the plurality of locations, the oil supply hole at one adjacent location and the oil supply hole at the other adjacent location are offset in the circumferential direction of the clutch hub.

8. The hydraulic clutch according to claim 3, wherein the inlet is opened in a vertical wall portion extending from the inlet portion toward the rotation center.

9. A forward / reverse switching unit having two hydraulic clutches as described in claim 1, and a speed change unit that changes the speed of power from a power source and outputs it to the forward / reverse switching unit, The forward / reverse switching unit is a power transmission device for a work vehicle that, when one of the two hydraulic clutches is switched to the engaged position, converts the power from the transmission unit into forward power and outputs it to the running gear, and when the other of the two hydraulic clutches is switched to the engaged position, converts the power from the transmission unit into reverse power and outputs it to the running gear.

10. A forward / reverse switching unit having two hydraulic clutches as described in claim 3, and a speed change unit that changes the speed of power from a power source and outputs it to the forward / reverse switching unit, The forward / reverse switching unit is a power transmission device for a work vehicle that, when one of the two hydraulic clutches is switched to the engaged position, converts the power from the transmission unit into forward power and outputs it to the running gear, and when the other of the two hydraulic clutches is switched to the engaged position, converts the power from the transmission unit into reverse power and outputs it to the running gear.

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