JPS616037A - Running speed changing device for truck - Google Patents

Abstract

PURPOSE:To easily and quickly perform operation by connecting a hydraulic clutch to a speed change lever so as to automatically be switched and operated interlocking with the operation. CONSTITUTION:A speed change operation lever 11 is integratedly connected to the linear moving type spool 14 of a three-position switching valve V2 through a pin 17 without any play. The neutral position of the valve V2 is set to the clutch OFF position and the forward and backward switching position is set to the clutch ON position. A pin 16 is inserted in the reverse end of the spool 14 for a permeation hole 14A that is provided at the spool 14 and is long in the axial direction and the base end boss section 11a of a shift fork 11A is fit to the spool 14 with play. For the three-position switching valve V2, the neutral position range is extended as compared with the foreward and backward switching position.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a tractor, etc., in which a hydraulic clutch interposed in a transmission system is linked to a gear shift lever so that automatic KI7J conversion can be operated in conjunction with the operation of the gear lever. This invention relates to a traveling transmission device for a work vehicle.

[Prior art]

As a traveling transmission having a mechanism capable of automatic clutch switching of this type, the present applicant has previously filed an application for one having the following configuration. (Jitsukai 59-781
(No. 36) In other words, a second auxiliary gear transmission device is provided on the transmission side of the hydraulic clutch in order to obtain an extremely low speed used during trench digging work, etc., and the clutch of this transmission section is installed as shown in FIG. Shift fork that operates the sleeve (O11A)
A two-position switching valve (Ov) that can switch the state of pressure oil supply to the hydraulic clutch is connected to the hydraulic clutch (OC) operating circuit (022). In conjunction with the spool, the valve I rev is configured to be able to switch between a hydraulic clarification state in which pressure oil is introduced into the drain side, a hydraulic clutch engaged state in which h-'B is introduced into the hydraulic clutch side, and a busy automatic state. ing.

[Problem that the invention attempts to solve]

With the above configuration, when changing gears using the gear lever, the pressure oil supply to the hydraulic clutch is temporarily cut off before shifting, thereby achieving smooth gear shifting with less shock. However, for this reason, it is necessary to use a C-shape with the f and # directions of the gear shift lever different during gear shifting operation and when the hydraulic clutch is engaged, which may be cumbersome in terms of operation, or there may be problems with improvement. There was room for.

An object of the present invention is to provide a gear shift lever and shift fork that can be easily and quickly operated by simply modifying the linkage structure of the shift lever and shift fork.

[Means to solve the problem]

The characteristic configuration of the present invention is that the shift fork and the gear lever, which perform two types of gear changes by forward and reverse movement from a neutral position, are linked with a predetermined flexibility, and the three positions control the operation of a hydraulic clutch interposed in the transmission system. The switching valve and the speed change lever are inflexibly linked, and the neutral position of the valve is the clutch gJ position, and the forward/reverse switching position is the clutch engaged position, and its effects are as follows. This is number 9.

[For production]

In other words, by selecting a three-position changeable valve as the valve that controls the operation of the hydraulic clutch, the
1411f direction and the operating direction of the shift fork can be made to coincide with each other, and by simply operating the shift lever in a straight line, it is possible to perform a shift operation while turning on and off the automatic shift hydraulic clutch.

In addition, a certain degree of flexibility is provided in the connecting portion between the gear shift lever and the shift fork, so that the shift shock caused by the engagement of the hydraulic clutch and the shift operation being performed at the same time, or when the shift operation is slightly preceded by ff1K, can be avoided. , absorption can be alleviated by allowing the hydraulic clutch to engage in advance by the amount of flexibility.

〔Effect of the invention〕

By simply selecting a valve with a switching direction that matches the operating direction of the shift fork and making simple modifications to the connecting part between the gear shift lever and shift fork, it is possible to provide a system with excellent operability that allows for comfortable work operations. It came to this.

〔Example〕

Figure 1 shows the transmission structure inside the transmission case (equipment) equipped on the tractor, which is connected to the input shaft +11 interlocked with the engine fEl and the first transmission shaft (2) for traveling, allowing for four-stage power exchange. A synchromesh type main gear transmission (Hl) is provided, and a friction plate type hydraulic clutch (C1) is provided between the first transmission shaft (2) and the second transmission shaft for traveling (3), and the second transmission shaft (3) A synchromesh type forward/reverse gear transmission (H2) which changes the output from forward and reverse; and a synchromesh type first auxiliary gear transmission (H2) which can freely shift the output from there to two high and low gears.
3) and a second auxiliary gear transmission (H4) which can freely switch the output from the second gear into two high and low stages, and
The output of the auxiliary gear transmission (H4) is transferred to the rear wheel (4) differential mechanism (4A input) and the front wheel (5) differential mechanism (5A) K transmission!
There is no Kli to make IJ.

A synchromesh type gear transmission (7) is provided which changes the power of the input shaft (1) into four stages and transmits it to the power extraction transmission shaft (6). 8
) is provided with a relay transmission shaft (9), so that the speed of the power take-off shaft (8) can be changed.

Next, the gear change operation structure for the one-travel transmission system will be described in detail with reference to FIGS. 1 and 3.

That is, the main gear transmission (Hl) includes a hydraulic cylinder (IOA) for operating a gear shifter that is selectively operated;
(IOB), and a hydraulic cylinder (6) for operating the first auxiliary gear transmission (H,)Kb transmission shifter.
one of the hydraulic clutches (C1,
It is equipped with a hydraulic cylinder for entry operation.

The main gear shifting hydraulic cylinder (IOA), (IO
B) and a main control valve (VO) for each of the first auxiliary transmission hydraulic cylinder (6), and the forward/reverse transmission three-position switching valve (V2) are connected in parallel to a hydraulic pump (P). . And each of the hydraulic cylinders (IOA) -
3-position switching valves (s2), (S, ), and (S4) are configured with the piston of . In addition to providing an oil passage - for supplying oil to
), (H2), (T, ), and ('T4) are arranged in series, and the main gear shifting hydraulic cylinder (
IOA), (IOB), and a switching valve (S□) S4), which is configured for each of the first auxiliary transmission hydraulic cylinder (goods),
(S2) and 3-position switching pulp for forward/forward shifting (H2)
A valve (T1) that is provided to be operated with pressure oil from the valve and thereby controls the operation of the clutch operation cylinder (b).
, ('r2), c'r,) r ('r4),
Main gear transmission (Hl), forward/reverse gear transmission (H2)
In order to change the paper-feeding operation position KFl only in the transmission state of the first auxiliary gear transmission (Hl) and the first auxiliary gear transmission (Hl), the KI71 change operation is performed independently in conjunction with the speed change operation.

However, the two hydraulic cylinders (of the main gear transmission (Ho))
Km is set so that when one of IOA) and (IOB) is suddenly operated to the shift side, the other hydraulic cylinder is operated and held at the shift neutral position by pressure oil. Further, the second auxiliary gear transmission (H4) is provided with a shifter 7 that can be freely operated with a speed change lever. Furthermore, the transmission device (7) for the power take-off shaft (8) K is configured to perform an artificial shift operation.

Main control valve and 3-position exchangeable pulp ff1), (V,) and clutch operation control valves (T,), (H2), (T,)
A main relief valve (G) is installed on the upper side of the flow path than (H4), and the exhaust oil from the main relief valve (G) is supplied to the hydraulic clutch tel for lubrication.

However, H8, ■, and (F□) to (H8) each indicate the operating position of the main control valve (vl), and
indicates the operating position of the auxiliary control valve (H2).

The forward/reverse gear transmission (H2) comprises a second driving transmission shaft fal K, a differential mechanism for front and rear wheels (4A), (5A) K interlockingly connected via an idle gear (to). By loosely fitting the forward gear Q9 and the forward gear wing located opposite to each other across the clutch sleeve (2), and by the switching operation (1thlK) of the shift fork (11A) engaged with the clutch sleeve (2), which will be described later, Advance gear shifting is possible.

As shown in FIG. 3, the 3-position switching knob (H2)
The speed change operation lever (-(B)) is integrally connected to the linearly moving spool α4 of the valve (H2) through pin A71, and the neutral position of the valve (H2) is set to the clutch disengaged position, and its forward/reverse switching position is set to the clutch disengaged position. At the opposite end of the spool I, a pin (G) is inserted into the axially long through hole (14A) K provided in the spool (141), and the shift fork (11A) is inserted into the spool (141). Proximal boss @(ll
a) is flexibly fitted onto the spool aIO. Furthermore, the range of the neutral position of the three-position switching pulp (H2) is larger than that of the forward/reverse switching position.

Therefore, to explain in detail the state of switching from forward to reverse, when the shift operation lever (B) is operated toward the neutral position, the spool α→ is operated to the neutral side and the clutch (C1 is set to 17
If it is IK, the shift fork (11A) will operate with a delay of spool α111K due to the passage of the connection string between spool α → and shift fork (11A), and clutch tc)
If a gear shift is performed while the vehicle is tilted, the gear will shift. When the gear is shifted further from this neutral position to the reverse side, the spool Q → and the shift fork (11A) operate simultaneously, but since the neutral range of the switching valve (H2) is large, the clutch is activated after the gear shift is performed. (C1 is turned on. Also, the same applies when changing from reverse to forward. Therefore, forward and backward gear shifting operations can be performed with less gear shifting shock.

[Another example]

The above embodiment may be applied to the first auxiliary gear transmission ()(3)K.

In addition to being applied to the traveling transmission of a tractor, the traveling transmission described above can be applied to various work vehicles such as a combine harvester.

[Brief explanation of drawings]

The drawings show an embodiment of the traveling transmission device for a work vehicle according to the present invention, and Fig. 1 is an overall configuration diagram of the drive system, Fig. 2 is a hydraulic operation circuit diagram for a hydraulic clutch, and Fig. 3 is a diagram of a gear shift. FIG. 4 is a partial large-scale side view showing the state of connection between the fork and the control valve, and FIG. 4 is a perspective view showing the state of connection between the conventional shift fork and the control valve. αη...Shift lever, (11A)...Shift fork, (C)...Hydraulic clutch, tv+...
・White, 3rd place l17I exchange valve.

Claims (1)

[Claims] 1. A shift fork (11A) that performs two types of speed changes by forward and reverse movement from a neutral position and a speed change lever (11) are linked with a predetermined flexibility, and are interposed in a transmission system. A 3-position changeover valve (V_2) that controls the operation of the hydraulic clutch (C) and the shift lever (11) are inflexibly linked, and the neutral position of the valve (V_2) is changed to the clutch disengaged position, and the A traveling transmission device for a work vehicle in which the forward/reverse switching position is the clutch engagement position. 2. The travel transmission device according to claim 1, wherein the two types of speed change are forward and backward switching speeds. 3. The traveling transmission according to claim 1 or 2, wherein the three-position switching valve (V_2) is a linearly moving spool valve.