JPH0582639U - Shift detection device for non-clutch vehicles - Google Patents

Abstract

(57) [Abstract] [Purpose] In a non-clutch vehicle such as a tractor, the shape of the check valve provided in the piston part that operates the shift shaft by the hydraulically operated shift fork is
(EN) Provided is a gear shift detection device for a non-clutch vehicle, which prevents malfunction of pressurization of pressure oil supplied to a traveling hydraulic clutch by changing between a neutral position and another gear position. [Structure] The groove shape of the actuator part of the check valve provided in the piston part of the shift cylinder in a non-clutch vehicle is configured so that it is shallow at the neutral position and deep at other shift positions, and the check valve is quickly activated at the neutral position. It is opened to prevent the generation of gear noise during gear shifting.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 In a non-clutch vehicle such as a tractor, the present invention is designed for traveling by changing the shape of the check valve provided in the piston portion that operates the shift shaft by a hydraulically operated shift fork between the neutral position and another gear shift position. The present invention relates to a speed change detection device for non-clutch vehicles, which prevents malfunction of boosting pressure oil supplied to a hydraulic clutch.

[0002]

[Prior Art]

 2. Description of the Related Art Conventionally, it has been known that in a work vehicle such as a tractor, so-called non-clutch gear shifting is performed in which the traveling hydraulic clutch is automatically disengaged in conjunction with a shift operation of the traveling transmission. Then, a shift control valve that is switched in conjunction with the operation of the shift lever and is held at each shift position via a positioning plate, and a vehicle for traveling according to each shift position of this shift control valve. A rotary valve that shifts the shift shaft of the transmission through the piston part of the shift cylinder and a hydraulic clutch for traveling of the work vehicle are connected and disconnected via the boost control circuit in conjunction with the switching operation of the shift control valve. And a hydraulic clutch control valve for controlling. In addition, when shifting the main shift section, there is a check valve function by sliding the piston of the main shift, and the check valve operates at each shift position to send pressure oil to the traveling hydraulic clutch.

[0003]

[Problems to be solved by the device]

 By the way, in the above-mentioned prior art, it is necessary to increase the synchronizing capacity or lengthen the synchronization time in order to prevent gear noise during gear shifting operation of the transmission, and especially in the case of synchronization. When the piston speed is slowed down to prolong the time, for example, when shifting from 1st gear to 2nd gear, it passes through the neutral position. At this time, the check valve is closed and pressure oil is sent to the traveling hydraulic clutch. However, there was a problem that the gear squeal occurred because the clutch was engaged and the gear shifted.

Therefore, according to the present invention, the shape of a check valve provided in a piston portion for operating a shift shaft by a hydraulically operated shift fork is changed between a neutral position and another shift position to supply the hydraulic clutch for traveling. It is an object of the present invention to provide a gear shift detection device for a non-clutch vehicle, which prevents erroneous pressure boosting of the pressure oil and prevents gear noise during gear shifting.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a shift control valve which is switched in conjunction with the operation of a shift lever and is held at each shift position through a positioning plate, and each shift control valve. Depending on the position, the shift shaft of the work vehicle travel transmission is operated by a rotary valve that shifts through the piston part of the shift cylinder, and the work vehicle travel hydraulic clutch is linked to the switching operation of the shift control valve. In a non-clutch vehicle equipped with a hydraulic clutch control valve that is intermittently controlled via a boost control circuit, the groove shape of the actuator portion of the check valve provided in the piston portion has a shallow neutral position and other shift positions. The feature is that it is deepened and the check valve is opened earlier at the neutral position.

[0006]

[Action]

 With the above configuration, the gear shift detection device for a non-clutch vehicle of the present invention makes the groove shape of the actuator portion of the check valve provided in the piston portion shallow at the neutral position and deep at the other gear positions so that the gear shifts quickly at the neutral position. Since the check valve is opened, it becomes difficult to supply pressure oil to the clutch when the shift cylinder passes the neutral position, and the clutch disengages well during non-clutch shift to prevent gear noise.

[0007]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 shows a tractor 1 as a work vehicle to which the present invention is applied. The tractor 1 has a shift lever 3a and N (neutral) shift positions 1 to 8 on the side of a control seat 2. A travel speed change operation device 3 including a speed change guide 3b is provided. A rotary valve 5 shown in FIGS. 1 and 4 is connected to the shift lever 3a so as to be rotated by the shift operation, and is rotated in association with the shift operation of the shift lever 3a to switch the shift control valve. The non-clutch shift is performed so that the traveling hydraulic clutch 4 is automatically disengaged.

A positioning plate 6 is provided on the outer peripheral portion of the rotary valve 5 that is switched by the shift lever 3a, and the rotary control valve 5 holds the shift control valve at each switched position and rotates the rotary valve 5 at each switched position. In response to this, the spool of the hydraulic clutch control valve 7 for intermittently controlling the traveling hydraulic clutch 4 is switched and operated. The rotary valve 5 is connected to an auxiliary transmission cylinder 8, a first main transmission cylinder 9, and a second main transmission cylinder 10, which are hydraulic actuators that shift the travel transmission. Check valves 8a, 9a and 10a are provided in the cylinders 8, 9 and 10, respectively, so that the hydraulic oil is sent to the traveling hydraulic clutch 4 only after the completion of the shift operations. Although not shown, a forward / reverse switching mechanism is separately provided, and the switched rotational output can be switched by the auxiliary transmission cylinder 8.

The positioning plate 6 is engraved with respective switching ranges of N (neutral) and A to H (port) corresponding to each shift position of the shift lever 3 a, and a spool of the hydraulic clutch control valve 7 is provided on this. Are in sliding contact with each other, so that the port of the hydraulic clutch control valve 7 can be switched at the same time when the shift control valve of the rotary valve 5 is switched. In the present invention, the circuit configuration is such that pressure oil is applied to the traveling hydraulic clutch 4 even in the N (neutral) position, and the holding pressure is preliminarily applied to the first speed side. Since hydraulic oil is applied to the traveling hydraulic clutch 4 even in the neutral N position, there is a pressure increase time when starting from the neutral N position and when shifting from a position other than neutral N to another shift position. There is no difference, and the start from the neutral N position is smooth.

Further, the auxiliary transmission cylinder 8 performs switching from neutral N to H (high) and L (low) in the A and B ranges (ports), and the first main transmission cylinder 9 operates from neutral N to the first speed. And the second speed are switched in the C to E ranges (ports), and the second main transmission cylinder 10 switches the neutral N from the third speed to the fourth speed in the F to H ranges (ports). There is. Further, when the shift lever 3a is shifted to the neutral N position, the circuit configuration is such that the holding pressure is applied to the traveling hydraulic clutch 4 on the first speed side in advance as described above. You can start without shock.

A step-up control valve 11 is provided on the lower side of the hydraulic clutch control valve 7 in the hydraulic path so that the hydraulic oil to the traveling hydraulic clutch 4 is slowly raised. The traveling hydraulic clutch 4, the rotary valve 5, the positioning plate 6, the hydraulic clutch control valve 7, the auxiliary shift cylinder 8, the first main shift cylinder 9, the second main shift cylinder 10, the boost control valve 11 and the like are used. , A non-clutch shift hydraulic circuit 12.

On the other hand, as shown in FIG. 4, a rack shaft 13 that slides by a shift lever 3a is provided, and this rack shaft 13 meshes with a pinion gear 14 to rotate the rotary valve 5. C, D and E are hydraulic ports for actuating the piston 9b, and actuate the check valve 9a via the ball 15, pin 16, check valve ball 17, valve seat 18 and return spring 19. . Reference numeral 20 denotes a shift fork, which is adapted to change gears by pushing and pulling the piston 9b through joints 21a and 21b.

As shown in FIG. 3, in the check valve 9a, when the first gear and the second gear are switched to the neutral N by the piston 9b, the depth of the groove of the neutral N fitted with the ball 15 is the first gear and the second gear. It is shallower than the groove depth of 1 by this. Therefore, when the check valve 9a is closed, the gap L between the check valve ball 17 and the pin 16 is small in the neutral N, but is large in the first speed and the second speed. Has become.

Next, the operation of the hydraulic circuit of the non-clutch vehicle according to the embodiment configured as described above will be described. First, the forward / reverse switching mechanism is shifted to either forward or reverse, and the shift lever 3a is moved along the shift guide 3b from the neutral N position to a desired shift position (from 1st speed to 8th speed). To do. Then, the rotary valve 5 is rotated in conjunction with the shift operation of the shift lever 3a, and the positioning plate 6 holds the shift control valve at the switching position, and at the same time, the spool of the pressure clutch control valve 7 is held. Is switched and pressure oil is supplied to the traveling hydraulic clutch 4 via the boost control valve 11.

When the rotary valve 5 rotates and the shift control valve is switched, any one of the sub shift cylinder 8, the first main shift cylinder 9, and the second main shift cylinder 10 that shifts the traveling transmission device. Is operated to switch the traveling transmission device, and after the shift operation is completed, pressure oil is sent to the traveling hydraulic clutch 4 via any of the check valves 8a to 10a. Further, by switching the spool of the hydraulic clutch control valve 7, pressure oil is sent to the boost control valve 12, the pressure oil is slowly raised and sent to the traveling hydraulic clutch 4, and the clutch is connected to connect the tractor 1 to the hydraulic clutch 4. Runs.

When shifting from the first speed to the second speed in such a non-clutch shifting operation, the rotary valve 5 rotates via the rack shaft 13 and the pinion 14, and at the same time, the spool of the hydraulic clutch control valve 7 is rotated. The oil of the traveling hydraulic clutch 4 flows to the tank when activated, and the rotary valve 5 switches the pressure oil to the first main transmission cylinder 9 to the C and D ports in the first speed and the E port in the second speed. In the first main transmission cylinder 9, the piston 9b slides and pushes up the check valve ball 17 via the ball 15 and the pin 16, so that the traveling hydraulic clutch 4 is in the disengaged state. Then, when the ball 15 completely enters the groove, the check valve 9a is closed, so that pressure oil is sent to the traveling hydraulic clutch 4.

Here, if the gap L between the pin 16 and the check valve ball 17 is small, the traveling hydraulic clutch 4 is easily disconnected, but the boost control valve 11 is difficult to raise the pressure, and oil flows to the traveling hydraulic clutch 4 side. Hateful. If the gap L between the pin 16 and the check valve ball 17 is large, the traveling hydraulic clutch 4 is hard to disengage, and the boost control valve 11 is easy to boost the pressure. In the present invention, the gap L between the pin 16 and the check valve ball 17 is set to be small at the time of the neutral N and increased at the times of the first speed and the second speed. Therefore, when shifting from the first speed to the second speed through the neutral N. Therefore, no oil is sent to the traveling hydraulic clutch 4 side, and therefore the traveling hydraulic clutch 4 is not engaged, so no gear squeal occurs. Needless to say, the shift detecting device for a non-clutch vehicle of the present invention is applicable not only to the tractor 1 but also to other work vehicles.

[0018]

[Effect of the device]

 As described above, according to the gear shift detection device for a non-clutch vehicle of the present invention, the groove shape of the actuator portion of the check valve provided in the piston portion of the gear shift cylinder that shifts the shift shaft of the drive gear for traveling is neutral. The position is shallow and the other shift positions are deep, and the check valve is opened early at the neutral position.Therefore, pressure oil is supplied to the traveling hydraulic clutch when the shift cylinder passes the neutral position. It is difficult to do so, and it is possible to improve the disengagement of the clutch during a shift. Further, it is possible to prevent the gear squeal accompanying the shift.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a traveling system hydraulic control device for a work vehicle according to the present invention.

FIG. 2 is a perspective view of a tractor to which the present invention is applied. ..

FIG. 3 is a detailed view of a check valve unit according to the present invention.

FIG. 4 is a unit diagram of a main transmission cylinder, a rotary valve, and the like.

[Explanation of reference numerals] 1 tractor 2 pilot seat 3 traveling gearshift operation device 3a shift lever 3b
Shift guide 4 Traveling hydraulic clutch 5 Rotary valve 6 Positioning plate 7 Hydraulic clutch control valve 8 Auxiliary shift cylinder 9 First main shift cylinder 9a Check 9b Piston 10 Second main shift cylinder 11 Boost control valve 12 Non-clutch shift hydraulic circuit 13 Rack shaft 14 Pinion gear 15 Ball 16 Pin 17 Check valve ball 18 Valve seat 19 Return spring 20 Shift fork 21a, 21b Joint L, l Gap

Claims (1)

[Scope of utility model registration request] 1. A shift control valve that is switched in conjunction with the operation of a shift lever and is held at each shift position via a positioning plate, and a work vehicle travels according to each shift position of this shift control valve. A shift valve of a transmission for a vehicle is operated to change gears via a piston of a transmission cylinder, and a hydraulic clutch for traveling of a work vehicle is connected and disconnected via a boost control circuit in conjunction with a switching operation of the shift control valve. In a non-clutch vehicle equipped with a hydraulic clutch control valve for controlling, the groove shape of the actuator part of the check valve provided in the piston part is configured such that the neutral position is shallow and the other shift positions are deep, and A gear shift detection device for a non-clutch vehicle, characterized in that the check valve is opened early.