JPS5989856A - Power transmission - Google Patents

Abstract

PURPOSE:To allow a neutral maintaning mechanism to cause no interference at all with speed change operation and promptly perform the speed change operation without causing any necessity for forming a transmission in a large size, by operating the neutral maintaining mechanism as a fluid pressure control type stopper which applies the fluid pressure only at operation to the neutral condition. CONSTITUTION:Fluid pressure control type stoppers 28, preventing the sliding of pistons 19 to and from the neutral position, are internally equipped and hit parts 29 preventing movement of the stoppers from their working position to a side of the piston 19 are provided in cylinder tubes 18 of the first and the second pistons 19, while a flow passage 26, which automatically applies an operating fluid pressure to the both stoppers 28 only when a speed change operating valve V1 is placed in the neutral condition, is provided. When a shift fork 21 is shifted to be switched from the speed change position to the neutral position, pressurized oil is supplied to major contour parts 18a in the both bottom sides through the oil passage 26 under the condition such that minor contour parts 18b in the both plunger sides are placed in an oil discharge condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a first piston that slides the speed change operation member in the seventh direction and a second piston that slides the speed change operation member in the @2 direction opposite to the vJ/ direction. and first and second cylinder chambers are provided to apply shift operation pressure to each of the pistons, and fluid pressure is applied to either one of the cylinder chambers during a shift state, and fluid pressure is applied to both cylinder chambers during a shift state. The present invention relates to a power transmission that is provided with a gear shift operating member for switching to a neutral state in which the gear shift operating member is not in a neutral state, and a neutral maintaining mechanism that maintains the gear shift operating member at a neutral position in the neutral state of the gear shift operating pulse.

The neutral maintenance mechanism of the power transmission is configured by providing a pair of springs for biasing the speed change operation member toward the neutral position in a first direction and a second direction, respectively, and When the gear shift operating member is moved to the neutral position, the biasing force of these springs returns and holds the gear shift operating member to the neutral position.

However, if a spring with a large biasing force is provided in order to quickly return the gear shift operating member to the neutral position and reliably maintain the neutral position, the two cylinders for gear shift operation and the pump for them will become larger. However, there is a drawback that the shift operation member slides slowly toward the shift position.

In view of the above-mentioned conventional situation, an object of the present invention is to make it possible to quickly switch a gear shift operating member to a neutral position and a gear shift position by rationally improving a neutral maintaining mechanism, and to make it possible to quickly switch a gear shift operating member to a neutral position and a gear shift position. The aim is to downsize the operating structure.

A characteristic configuration of the present invention is that in the power transmission described above, the neutral maintenance mechanism includes cylinder tubes of the first and first copistons that are configured to move the pistons to and from the neutral position. A fluid pressure-operated stopper is installed inside to prevent the stopper from moving toward the piston, and a stopper is provided to prevent the stopper from moving toward the piston. There is a need to provide a flow path for applying fluid pressure for operation, and its effects are as follows.

In other words, if the neutral maintenance mechanism is a fluid pressure operated stopper that does not apply fluid pressure when operating to shift state, but only applies fluid pressure when operating to neutral state.
Therefore, the gear shifting operation can be performed without any hindrance, and the gear shifting operation can be carried out quickly without increasing the size of the gear structure.

Furthermore, by making the stopper hydraulically operated in the same manner as the speed change mechanism, it is easy to simplify the drive structure of the stopper and the connection structure with the speed change operation, and in addition, the cylinder tube can be used for both the piston and the piston. Since it constitutes the fluid pressure operation structure of the stopper, the piston and the drive structure of the stopper can be greatly reduced in size.
Overall, it has been possible to provide a compact power transmission that is excellent both in terms of structure and shift operability.

Next, embodiments of the present invention will be described in detail based on illustrative drawings.

As shown in Fig. 1, the power from the prime mover (E) is transferred to the main shifting mechanism (1), hydraulic multi-disc clutch t2), auxiliary shifting mechanism (3) and The configuration is such that the power is transmitted to the super deceleration mechanism (4) in that order, and the assist power from the super deceleration mechanism (4) is transmitted to the rear wheels (5) via the rear wheel differential device (7). It is configured to transmit the load to the front wheels (6) through the shaft (8) and the front wheel differential device (9), thereby forming a drive device for a V-wheel drive working vehicle such as a tractor.

Furthermore, within the mission case, the power from the upper side of the main transmission mechanism (1) is transferred to the PTO transmission mechanism (10).
and a hydraulic multi-disc clutch (+1) to transmit the PTO shaft α2)K for driving the working device.

Below, each transmission mechanism (1) + [31l +41- (
101 will be explained in detail.

The main transmission mechanism (1) is composed of drive side gears (G,), (G,)ν('G3), each having a different number of teeth.
tCG4) are installed in parallel to the input shaft (Sl) so as to be able to freely rotate integrally with each other, and the drive side gears (G1), (G, ), (
G3)! v passive side gears (G5), (G8), (G, ), (G8) that are always engaged with (G4) are respectively attached to the traveling power system passive shaft (S2) so as to be freely rotatable, and Adjacent passive gears (G,), (G6), (C;,)
1 each between I (G8) and 9 adjacent gears (G5
) Two sets of synchromesh type shift devices (13a) t('13b) are provided which selectively connect one of I(G6) and (Gy) I(Gs) to the passive shaft (S2),
Therefore, the configuration is such that a gear shift is performed by operating these shift devices (13a) and (13b).

The auxiliary transmission mechanism (3) includes a J-shaft (J-shaft) which receives power transmission from the main transmission mechanism (1) via the first clutch (2).
SA) K % The first tag gear (G9) that is always engaged with the reverse relay gear (GB), and the first gear pair (Gl.)' (Gll) which are integrally connected, each having a different number of teeth
GG, ') are respectively attached to be freely rotatable, and the first reverse relay gear (GB) K is always engaged with the gear (G1) that is always engaged with one gear (Gl.) of the first gear pair (GGl). A second gear pair (G
G, ), and the other gear (GQI) of the seventh gear pair (GQI)
The gear (G14) that is always engaged with the second axis (G11) is
4) They are attached so that they can rotate freely. Then, the gears (G, ) and ( G14) and gear pair (GG
l) I (GG2) and the third axis (G3) or the G axis (
A synchromesh type shift device (I4) 1 (tg) is alternatively connected integrally to the third shaft (S
, ) side shift device θ4) operation to perform forward/reverse travel, and the first daxle (G4) side shift device θ4) operation to perform high/low speed switching operation.

To configure the super reduction mechanism (4), a final output shaft (G6) is provided coaxially with the first shaft (G4), and a first shaft (G6) is provided coaxially with the first shaft (G4).
G4) is passed through the super reduction gear mechanism (4a) to bypass the MJ shaft (S,), and then
, )' and a state in which it is directly connected to the final output shaft (SS) tl.
It is configured so that the I operation switches between a super deceleration state and a normal speed change state.

In other words, the above-mentioned main transmission mechanism (1), auxiliary transmission mechanism (3)
, and super-reduction mechanism (4) K are configured to be able to perform 72-speed forward and reverse gear shifts by shifting the super-reduction mechanism (4) K, and the power transmitted to the final output shaft (G6) is transferred to the PTO output shaft (G6).
8) The transmission shaft (8) side gear (GF') is interlocked with the front wheel transmission shaft (8) via a freely rotatably mounted relay gear (GF), and the relay gear (GF) engages with the transmission shaft (8). ) can be freely shifted between a power transmission state and a non-power transmission state, and is configured to be switched between a single-wheel drive state and a two-wheel drive state.

The PTO transmission mechanism (one gear consists of the drive side gears (G,) I (Gri, (G, ), (G4) K gears (Gas) that are always in mesh with each other at all times) 9 (Gas) 9(
G17) ・(GlP), Pro type passive axis (S,')
Each K is installed so that it can freely rotate, and the adjacent free rotating gears (G15) I (G16), (G17) I (G18)
Between each free rotating gear (G15) I (G16) / (G17)
Synchronous mesh shift device (17) that integrally connects I (Gls) with alternative K
a) + (17, b) is provided, and the configuration is such that a PTO system double speed change can be performed.

Each synchromesh type shift device (13a) + (1
3b) +(14) I(+61 l (17a)+(
In order to perform the shift operation of 17b), seven common plungers 99) are slidably provided across τ pairs of pilot cylinders (18) Ic that are concentrically opposed, and each shaft (S) and K are integrally connected. Rotatable and shiftable VC
Shift fork (21) for the installed shift member
is connected to the intermediate portion of the plunger 01, and the pusher (I!i) is configured to slide by supplying pressure oil to both cylinders (18).

Next, the hydraulic operation structure of each transmission mechanism (1) + +311 (Sol) will be explained in detail with reference to FIGS. 1 and 2.

In the main transmission mechanism +1) and the auxiliary transmission mechanism (3), the pressure oil supply path - from the operating pressure oil pump (P) is connected to one shift device in the main transmission mechanism f+1 via the traveling transmission pulp (vl). (13a,)t(13b) and the respective pilot cylinders α~ of the high/low speed switching shift device 0119 in the sub-transmission mechanism (3), and are connected in parallel to each other,
In parallel with the traveling transmission system, the pressure oil supply path (2) is connected to the pilot cylinder (18Hc It is connected.

Then, the traveling speed change pulp (vl) is moved to the neutral position (N
) is included in the switching valve (N1F1~ps),
By operating the traveling speed change pulp (vl), the three shift devices (13a) + (13b) connected to it
++15) at the same time, and those! 2 in the normal combination operating state (that is, switching the operating state of the high/low speed switching shift device (15) and the main transmission mechanism fl).
The configuration is such that one of the two shift devices (13a) + (13b,) is held neutral while the other is switched to perform an I-speed gear shift operation. By operating the forward/reverse switching pulse (V2), a two-speed gear change is performed for both forward and reverse.

Each shift device [(13a)=(13b) I(141'
(With Iftl's plunger sauce also used as a sliding spool, two 3-position switching valves (fl) and (y2)l are connected to the pressure oil from each operating pulp (vl) and (v2).
(6) ν (me), which connects the J position switching valve (stone) of the forward/reverse switching system and the hydraulic operating part of the traveling system clutch (2) through a single oil passage (23), the other three 3
Position switching valve (f2) +073)/(1-r4) to (7
) Pressure K J: ri A position switching valve (right) and 017'3) I(r+) that is operated separately is installed in series in the oil passage (to), so that the front and rear Shift device for forward speed switching (14) and shift device for high/low speed switching (1
5) are both in the non-neutral state ff1K, and the main transmission mechanism (1
) Only when one of the shift devices (13a) + (13b) in K is in a non-neutral position, is the running system? It is configured so that the latch (2) is engaged and in operation, and the pulp for traveling speed change (Vl), the pulp for driving, and the pulp for forward/reverse switching (
When operating V2) from one shift position to another, the drive system clutch (2) automatically shifts to
The drive system clutch (2) is configured to automatically engage and operate when either of the shift members, which were in the neutral state, is switched to the active state.

Off PTO transmission a (in the first case, the pressure oil supply path (2) from the pump (P) is connected to the PTO transmission pulp (
V, ) via two shift devices (17a) + (17b
) is connected in parallel to the pilot cylinder (18) of the shifter (17a), and one shift device (17a ) + (17b) at the same time to create a V-combined operating state (switching one shift device (17a)?(17b) while holding it in neutral) and shifting the other shift device (17a) to PTO. The system is configured to perform a gear shift operation.

Then, by using the pusher (l→ of the shift device (17a) + (17b) as a sliding spool, two J position switching valves, ) and (y6) are constructed, and one of the J position switching valves (y , )・(v6) Two two-position switching valves (4) + (6) each operated separately by pilot pressure are connected to the pump (P) and the hydraulic operation part of the PTO system clutch (+1). A button is inserted in series with the oil passage (goods) to be used, and with that,
Both shift devices (
When 17a) and (17b) both become neutral,
Either shift device (17a) 1 (17b) so that the PTO system clutch (U) is automatically disconnected and operated.
The structure is such that the PTO system clutch (11) is automatically engaged and operated when the clutch is switched to the engaged side.

Shift devices (13a), (13b) I (17a)+ in the main transmission mechanism fl+ and the PTO transmission mechanism (lO)
(17b) KS 1 as shown in Figure 3.
Each cylinder chamber of a pair of pilot cylinders for shift operation is formed with a bottom side large diameter portion (18a) and a plunger side small diameter portion (18b) communicating with the bottom side large diameter portion (18a). The sliding member side that divides it into two parts, the bottom side and the plunger side, is installed inside, and the bottom side large diameter part (18a) and the plunger side small diameter part (18b) are made of traveling speed change pulp ( V, ) or the oil passage (to) -fi from the PTO speed change valve (v3) are connected, respectively.

When operating the shift fork (2]) to the shift position in conjunction with the shift operation of the pulp (Vl) and (V, ), both bottom side large diameter portions (18a) and one plunger With the side small diameter portion (18b) drained, the other Pushinger side small diameter portion (18b) is
), and the corresponding two-position switching valve (REI'6) K pressure oil is supplied through its small diameter portion (18b), and the sliding member (2 barrels) on the side receiving the pressure oil supply is After sliding the plunger (11f:
When extended, the shift fork @IJ'lt: is configured to operate the 1- and 2-position switching valves (v'1 to 4) at the shift position.

In addition, when switching the shift fork shaft υ from the gear shift position to the neutral position, the small diameter portion on both plunger sides (is
With b) in the oil draining state, both bottom-side large diameter parts (18a) K pressure oil is supplied through the oil passage (a), and both seed moving members (c) move to the neutral position side. The shift fork (21
) is returned to the neutral position, and in the neutral position, both types of moving members (c) are prevented from sliding by the step s@ between the small diameter portion (18b) and the large diameter portion (18a). The shift forklift 1) is held in the neutral position by the position regulating action on the plunger (K?), and the corresponding two-position switching valve (9-11t) is controlled by the plunger (19) (K?). It is configured to communicate with the drain side via the weeping oil groove and to switch between them.

The cylinder (1 barrel) is constructed as shown in Fig. 4, and includes a cylinder chamber part (18b) in which the plunger (19) is housed, and a sliding member (c) which acts as a stopper against the plunger haze. The cylinder chamber part (1
8a) to have the same inner diameter, and a sliding member (c) between both cylinder chamber portions (18a) + (18b).
The specific structure and shape of the cylinder θ field in which the stopper (c) is internally formed has a small diameter portion as an abutting portion for preventing movement from the operating position toward the pusher 69), and various configuration changes are possible.

The present invention is applicable to various work vehicles such as agricultural work vehicles and construction work vehicles.
It is intended for various hydraulically operated power transmissions found in RO.

[Brief explanation of the drawing]

One drawing illustrates an embodiment of the power transmission according to the present invention, FIG. 1 is a schematic diagram showing the overall drive structure, and FIG.
3 is an enlarged sectional view showing a mechanism for maintaining neutrality of the gear shift operating member, and FIG. 4 is a diagram corresponding to FIG. 3 showing another embodiment. (Country...Cylinder tube, (18b)...
...Cylinder chamber, a side...Piston, (2
1)......speed change operation member, (2(υ......
Channel, e81... Stopper, (291... Self... Contact part, (vl)... Pal Z°.-

Claims (1)

[Claims] A first piston Of4 for sliding the speed change operation member (20 in a first direction) and a first piston H for sliding it in a second direction opposite to the first direction are attached, and both the pistons, (The IC4 is provided with a first and a first co-cylinder chamber (18b) that apply a gear-shift operation pressure separately, and both cylinder chambers (ISB) K are in a gear-shift state where fluid pressure is applied to one of them, and fluid pressure is applied to both cylinder chambers (ISB) K. A speed change operation pulp (vr) is attached to switch to a neutral state in which no
21) A power transmission is provided with a neutral maintenance mechanism for maintaining the first and second pistons (I9) in a neutral position, and in the neutral maintenance mechanism, the silling tubes of the first and second pistons (I9) are each provided with a A body pressure-operated stopper (c) is installed inside to prevent sliding to and from the neutral position, and the stopper (c)
A contact portion is provided to prevent movement of the piston from its operating position to the four sides of the piston, and a flow is provided that automatically applies operating fluid pressure to both stoppers when the speed change operating pulp (Vρ stops in a neutral state). A power transmission characterized by being provided with a road.