JPS6119858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tractor equipped with a transmission device using a hydraulic drive device in parallel with a gear transmission device.

In the past, tractors were mainly used for tillage work, but recently, tractors have been fitted with various working machines and used for many purposes. Therefore, there has been a need for a transmission device that can change speeds in multiple stages, especially to ultra-low speeds, depending on the work, but it is difficult to incorporate an ultra-reduction device into conventional small tractors due to space constraints in the transmission case. Ta. On the other hand, when doing light civil engineering work or pasture work using a tractor, there are many operations that frequently switch between forward and reverse, and at the same time, the hydraulic control lever is also switched. Conventional transmission systems that use selective meshing of gears instantly switch forward and backward. I couldn't do that, and it was very inconvenient. Furthermore, for pasture work, a so-called live PTO, which can be operated regardless of whether the vehicle is running, is very convenient, and the equipment of such a live PTO is desired.

In view of the above-mentioned circumstances, the present invention provides a transmission device using a hydraulic drive device with a differential reduction gear mechanism, and is configured to be able to stop the differential function of the differential reduction gear mechanism. It is an object of the present invention to provide a transmission device for a tractor that can run at low speed, instantaneously switch forward and backward movement with a simple operation, and also use the PTO as a live PTO.

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

As shown in FIG. 1, the tractor 1 has a body 5 supported by front wheels 2 and rear wheels 3. An engine 6 is mounted at the front of the body 5, and a driver's seat is mounted at the rear. 7 are arranged. Furthermore, a hydraulic pump 9 is arranged in the front of the engine 6, and a transmission case 1 is arranged below the driver's seat 7.
0 is placed. At the top of the case 10, a gear case 11 that protrudes toward the driver's seat 7 and incorporates a super deceleration mechanism and an instantaneous forward/backward switching mechanism (shuttle clutch mechanism) according to the present invention can be added to a conventional tractor transmission case. In addition, a hydraulic motor 1 is mounted on the front of the case 11.
2 is installed. Hydraulic motor 12 is connected to piping 13
The rotation of the engine 6 is transmitted to the input shaft 15 (see FIG. 2) extending into the transmission case 10 via the main clutch, and the hydraulic pump 9 is connected to the hydraulic pump 9 via the main clutch. 9 to the output shaft 12a of the hydraulic motor 12. Further, the driver's seat 7 is provided with a main gear shift lever 16, a selection lever 17 for switching between the super deceleration mechanism and the instantaneous forward/reverse switching mechanism, a forward/reverse switching lever 19 by the forward/reverse switching mechanism, a PTO shift lever 20, etc. has been done. As shown in FIG. 2, the transmission case 10 has a built-in gear transmission 21 that can change speed by selective meshing of gears. That is,
The rotation of the input shaft 15 is transmitted to the gear train sleeve 22 via the gear 15a, and further transmitted to the intermediate shaft 26 via the slide gears 23 and 25 switched by the main shift lever 16. Further, the rotation of the intermediate shaft 26 is transmitted to the traveling shaft 30 via the slide gear 27 and the gear 29, and the rotation of the shaft 30 is transmitted to the pinion 3.
1 and a differential gear to the rear wheels 3. Furthermore, the rotation of the gear train sleeve 22 is transmitted to the PTO shaft 35 via the slide gear 32 and gear 33 that are slid by the PTO speed change lever 20, and the PTO shaft 35 can drive the PTO. On the other hand, hydraulic motor 1
The second output shaft 12a is connected to a shaft 36 that is rotatably supported by the gear case 11.
A gear 37 having thick teeth is fixed to. A slide gear 40, which is slidably supported by the transmission shaft 39 and can be slid and switched by the selection lever 17, can mesh with the gear 37.
A gear 41 rotatably supported by 9 is always in mesh. A pawl 40 is provided on one side of the slide gear 40.
a is provided, and the claw 40a is connected to the gear case 11.
It can be engaged with a fixing claw 11a, which is a fixing member installed in the. Further, the gear 41 is connected to a casing 42 that can rotate around a shaft 39, and a planetary gear 43 consisting of two gears 43a and 43b with a slight gear difference is rotatably supported in the casing 42. has been done. Furthermore, the gear 4 is attached to the transmission shaft 39.
5 is fixed, and a gear 46 having a slightly larger number of teeth is rotatably supported adjacent to the gear 45. By meshing, a differential reduction gear mechanism 4 is configured. Therefore, in the differential reduction gear mechanism 47, the gear 41 integral with the casing 42 constitutes one input section, the transmission shaft 39 integral with the gear 45 constitutes the other input section, and the gear 46 constitutes the output section. It makes up the department. A boss portion of the gear 46 extends in the axial direction and is connected to a gear 49 having thick teeth, and the gear 49 is always meshed with the large gear 27a of the slide gear 27.

Since the present invention has the above-described configuration, first, in order to run the tractor 1 at a very low speed, the main shift lever 16 is set to the neutral position, and the slide gear 40 is slid by the selection lever 17 to fix the pawl 40a. It engages with the claw 11a. When the hydraulic motor 12 is driven with this transmission shaft 39 fixed, the output shaft 1
The rotation of 2a is transmitted to the casing 42 via the shaft 36 and gears 37, 41, and the rotation of the planetary gear 43 is transmitted to the shaft 3.
It revolves around 9. As the gear 45 rotates, since the gear 45 is fixed together with the transmission shaft 39, the gear 45
The planetary gear 43 rotates based on the meshing relationship between the gears 43b and 43a, and the differential between the revolution and rotation causes the gears 43b and 43 to rotate.
It is transmitted to the gear 49 based on the meshing of the gears 6 and 6. That is,
The numbers of teeth of the gears 45 and 46 are a and b, and the planetary gear 4
When the numbers of teeth of the gears 43a and 43b of No. 3 are c and d, the reduction ratio i has the following relationship: i=bc/(bc-ad). At this time, since the difference in the number of teeth between a and b and between c and d is small, the reduction ratio i becomes very large. As a result, the super-decelerated rotation of the gear 49 is transmitted to the slide gear 27, and a speed ratio based on the sliding position of the slide gear 27 is applied to the traveling shaft 3.
0, and the tractor 1 travels at an extremely low speed.

Next, when the tractor 1 is driven by the instantaneous forward/reverse switching mechanism, the main gear shift lever 16 is set to the neutral position, and the selection lever 17 is set to the slide gear 40.
meshes with gear 37. In this state, when the hydraulic motor 12 is driven, the gear 37 rotates.
Due to the meshing of the gears 40 and 41, the shaft 39, that is, the gear 45, and the casing 42 rotate in the same direction and at the same speed. As a result, the differential function of the differential reduction gear mechanism 47 is stopped, the planetary gear 43 revolves without rotating, and the gear 49 rotates integrally with the transmission shaft 39 due to the meshing of the gears 43b and 46. 4
The rotation of 9 is transmitted to the traveling shaft 30 as described above, and the tractor 1 travels. Furthermore, when the hydraulic direction control valve is switched using the forward/reverse switching lever 19, the direction of the hydraulic oil sent to the hydraulic motor 12 is switched.
Hydraulic motor 12 is reversed. As a result, the traveling axis 3
0 is also reversed, and the tractor moves in the opposite direction at the same speed as before.

Furthermore, when using the live PTO, the tractor 1 is driven at a very low speed using the aforementioned ultra-deceleration mechanism or by using the instantaneous forward/backward switching mechanism. That is,
The running shaft 30 is driven by the hydraulic motor 12 regardless of the gear transmission 21 . On the other hand, the rotation of the input shaft 15 is transmitted to the gear train sleeve 22 via the gear 15a. In this state, slide the slide gear 32 using the PTO shift lever 20,
When meshing with any gear of the gear train sleeve 22 or the gear 33, the PTO is activated by an appropriate gear ratio.
The shaft 35 is driven. As a result, a predetermined amount of power can always be extracted from the PTO regardless of the running state of the tractor 1 or whether the tractor 1 is stopped due to the stoppage of the hydraulic motor 12.

As explained above, according to the present invention, the differential reduction gear mechanism 47 is interposed in the transmission device by the hydraulic drive device 12, so the hydraulic drive device 12 is not used in an inefficient ultra-low speed range, and the tractor Not only can the PTO be driven at extremely low speeds, but the load on the PTO is usually greater than that of traveling during extremely low-speed work, but the PTO can be moved to the gear transmission 21.
It is possible to prevent a decrease in transmission efficiency by driving the hydraulic drive device 12 and prevent a decrease in work efficiency due to the hydraulic drive device 12 having low transmission efficiency. Furthermore, the other input section 39 of the differential reduction gear mechanism 47 is also connected to the one input section 41.
When connected to the output shaft 12a of the hydraulic drive device 12, the super deceleration is canceled by stopping the differential function, and the switching lever 19 operates the hydraulic directional control valve of the hydraulic drive device 12. Since it is possible to instantly switch between forward and backward travel, there is no need to operate the clutch or gear shift lever as in the case of conventional methods. It is possible to improve work accuracy without the need for
Moreover, the switching can be done smoothly because of the hydraulic drive system. Furthermore, when the tractor 1 travels based on the hydraulic drive device 12, the PTO shaft 3
Since the tractor 5 is driven via a gear transmission 21 that is not related to the traveling, it can be used as a live PTO, and the working range of the tractor 1 can be expanded. Further, since the device according to the present invention can be attached to the upper part of the transmission case 10, it can be easily attached to a small-sized tractor with little space, and can also be easily added to a conventional tractor.

[Brief explanation of the drawing]

FIG. 1 is an overall side view showing a tractor to which the present invention is applied, and FIG. 2 is a sectional view showing its transmission device. 1... Tractor, 10... Mission case,
11a... Fixed member (fixed claw), 12... Hydraulic drive device (hydraulic motor), 12a... Output shaft, 15
... Input shaft, 21 ... Gear transmission, 30 ... Traveling axis, 35 ... PTO shaft, 39 ... Other input section (transmission shaft), 40 ... Slide gear, 42 ... One input section ( casing) 46, 49...output section (gear, gear), 47...differential reduction gear mechanism.

Claims (1)

[Scope of Claims] 1. A tractor equipped with a hydraulic drive device that transmits engine rotation from an input shaft to a traveling shaft and a PTO shaft via a gear transmission and is driven by the engine rotation, the hydraulic drive device One input part of the differential reduction gear mechanism is connected to the output shaft of the differential reduction gear mechanism, a slide gear is connected to the other input part of the differential reduction gear mechanism, and the output part of the differential reduction gear mechanism is connected to the traveling shaft. and the slide gear is selectively engaged with an output shaft or a fixed member of the hydraulic drive device, and when the slide gear is engaged with the fixed member, the rotation of the output shaft of the hydraulic drive device is differentially controlled. The rotation of the output shaft is transmitted to the output section via the differential function of the reduction gear mechanism, and when the slide gear is engaged with the output shaft of the hydraulic drive device, the rotation of the output shaft is transmitted to the differential reduction gear mechanism without passing through the differential function. A tractor transmission device configured to transmit power to an output section of a tractor. 2. Claim 1, wherein the hydraulic drive device, the differential reduction gear mechanism, and the slide gear are installed in the upper part of the transmission case in which the gear transmission is built-in.
Transmission device for the tractor described in Section 1.