JPS6217628Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a multi-plate hydraulic clutch for a hydraulic clutch type transmission installed in a vehicle such as a tractor, in which a friction plate and a group of mating plates are received from the opposite side of a piston for actuating the clutch. This invention relates to a type of multi-plate hydraulic clutch that is equipped with a disc spring.

The above-mentioned type of multi-disc hydraulic clutch is already known, and when such a multi-disc hydraulic clutch is used for a vehicle forward gear in a hydraulic clutch type transmission, it is necessary to use a multi-disc hydraulic clutch when the vehicle starts or accelerates in the forward direction. This prevents the occurrence of shocks. In other words, when a vehicle such as a tractor whose rear wheels are the driving wheels is started or accelerated in the forward direction, the center of gravity of the machine tends to remain at the rear due to inertia. When the vehicle is driven under conditions where the distance between the ground driving point and the center of gravity of the aircraft is small, the front part of the aircraft tends to lift up, and a shock is likely to occur. In a plate-type hydraulic clutch, when the piston for actuating the clutch is advanced toward the friction plates and the mating plate group by hydraulic action, while the disc spring is being compressed, the disc spring acts against the hydraulic pressure to move the piston. Since the forward speed of the vehicle is slowed down, it is operated relatively slowly and in a buffer manner, so that the vehicle starts or accelerates in the forward direction relatively slowly, thereby preventing the occurrence of the above-mentioned shock. It will be done.

One object of this invention is to provide a novel multi-disc hydraulic clutch for a hydraulic clutch type transmission, which further enhances the above-mentioned advantages.

Next, the initial state that is established at the time of switching the position of the switching valve that switches and controls the supply and discharge of hydraulic pressure to the multiple hydraulic clutches is applied to the hydraulic pressure applied to the multi-disc hydraulic clutch of the hydraulic clutch type transmission installed in a vehicle such as a tractor. It is also known, for example, from JP-A-52-89757, to obtain shock-free operation of a multi-disc hydraulic clutch by providing a pressure regulating valve that gradually increases the hydraulic pressure for the clutch in this way. be. By the way, in such a hydraulic clutch type transmission, for example, when downshifting from 2nd forward speed to 1st forward speed, the pressure regulating valve does not completely return to the neutral state and suddenly high oil pressure is established, causing the transmitted torque to decrease. Even if the pressure regulating valve returns to an almost completely neutral state once, the transmission torque corresponding to the initial oil pressure is rapidly obtained when the initial oil pressure is established, resulting in poor deceleration feeling. was.

It is another object of this invention to provide a multi-disc hydraulic clutch of the type first mentioned, which when used in a hydraulic clutch type transmission configured to progressively increase the clutch operating pressure, An object of the present invention is to provide a new multi-disc hydraulic clutch which solves the problems.

The configuration of the multi-plate hydraulic clutch according to the invention will be explained with reference to the illustrated embodiment.
is a forward speed change shaft in a hydraulic clutch type transmission, and on this forward speed change shaft 1 are F ₁ gear 2F ₁ and F ₂ gear 2F ₂ fixedly installed on a driving shaft (not shown).
_F1 gear _3F1 and _F2 gear _3F2 meshed with
are loosely fitted through ball bearings 4 and 5, respectively. Also on the forward speed change shaft 1 is an F ₁ hydraulic clutch 7F ₁ whose clutch housings 6 are integrally formed back to back.
and _F2 hydraulic clutch _7F2 are provided, and the clutch housing 6 described above is fixed to the forward speed change shaft 1 by a key 8.

Each hydraulic clutch 7F ₁ , 7F ₂ has a plurality of friction plates 9 on the F ₁ gear 3F ₁ or the F ₂ gear 3F ₂ and a plurality of mating plates 10 on the clutch housing 6.
It is constructed as a multi-plate type in which each plate is arranged alternately and supported so as to be slidable only along the axial direction. A pressure receiving plate 12 is prevented from coming off by a retaining ring 11 mounted on the inner peripheral surface of the clutch housing 6.
In order to press the friction plate 9 and the group of mating plates 10 in the direction and frictionally engage the friction plate 9 and the mating plate 10 to obtain clutch operation, a A piston 13 is provided. This piston 13 is slidably biased in the backward direction by a return spring 14, and the piston 13 of each hydraulic clutch 7F ₁ , 7F ₂ connects oil passages 15F ₁ , 15F ₂ bored in the forward speed change shaft 1. The vehicle is moved forward by hydraulic pressure supplied to an oil chamber 16 at the rear through the vehicle. Each hydraulic clutch 7F ₁ and 7F ₂ has a friction plate 9 and a mating plate 1.
Disc spring 1 that receives the 0 group from the opposite side of the piston 13
7 is installed internally with both ends touching the pressure receiving plate 12 and the mating plate 10 facing it.

Although the above-described configuration is as usual, the pistons 13 of the respective hydraulic clutches 7F ₁ and 7F ₂ are provided with the respective oil passages 15F ₁ and 15 in the forward speed change shaft 1.
An oil passage ₁₉ that connects the hydraulic oil passages 18F ₁ and 18F ₂ formed in the clutch housing 6 to the oil chamber 16 of each hydraulic clutch 7F ₁ and 7F 2 to connect the hydraulic oil passages 18F 1 and 18F ₂ to the oil chamber 16 of each hydraulic clutch 7F 1 and 7F 2, It is provided. In the case shown, each hydraulic oil passage 18F ₁ , 18F ₂
An annular slot 18 is formed in the clutch housing 6 and each piston 13 at the communicating end with each oil passage 19.
a, 19a, the oil passage 19 of the piston 13 _, as shown for the _F2 hydraulic clutch _7F2 in FIG. Said passage 19
The slots 19a at the ends of the hydraulic oil passages 18F ₁ and 18F ₂ of the clutch housing 6 are provided so as to be out of position and blocked by the clutch housing 6. The distance d ₁ mentioned above is the first
As shown in the figure, the distance that the piston 13 brings the friction plate 9 and the mating plate 10 into close contact with each other due to its advancement.
It is set to be equal to or slightly smaller than d ₂ (d ₁ ≦d ₂ ). That is, the oil passage 19 is connected to the piston 13.
The clutch housing 6 blocks the clutch housing 6 when the friction plate 9 and the mating plate 10 are advanced until the friction plate 9 and the mating plate 10 are brought into close contact with each other.

Further, between each piston 13 and the clutch housing 6, in the illustrated case, on the inner circumferential surface of the piston 13, a groove hole 18a at the end of each hydraulic oil passage 18F ₁ , 18F ₂ of the clutch housing 6 is inserted into each oil chamber 16. A throttling oil passage 20 is provided which is in constant communication with.

Illustrated multi-plate hydraulic clutch 7 according to this invention
Since F ₁ and 7F ₂ are constructed as explained above, each of these hydraulic clutches 7F ₁ ,
When hydraulic oil is selectively supplied to 7F ₂ ,
While _the piston 13 is advanced to the position shown by _the chain line in _{FIG .} Hydraulic oil is supplied at a high rate to the oil chamber 16 behind the piston 13 through the provided oil passage 19, and the piston 13 is rapidly advanced, and the state in which the friction plate 9 and the mating plate 10 are brought into almost close contact is quickly achieved. can be obtained. After this state is achieved, since the oil passage 19 is blocked, hydraulic oil is supplied exclusively to the oil chamber 16 through the throttle oil passage 20 between the piston 13 and the clutch housing 6. In this way, by supplying hydraulic oil at a low rate to the oil chamber 16 behind the piston 13, the piston 13 is slowly moved forward, and the disc spring 17 is slowly deflected. The transmitted torque through the hydraulic clutch 7F ₁ or 7F ₂ will gradually increase. In other words, the clutch engagement time is not particularly delayed as is the case when hydraulic oil is supplied to the oil chamber 16 through the throttle or the throttle oil passage, and the gradual increase in the transmitted torque is caused by the disc spring 17 and the throttle. This is achieved by the cooperative action with the oil passage 20, and the above-mentioned advantages of the multi-plate hydraulic clutch with internal disc springs, namely, the advantage of preventing the occurrence of shock when the vehicle starts or accelerates in the forward direction, are achieved. can be greatly increased without any other problems.

Furthermore, when the illustrated multi-disc hydraulic clutches 7F ₁ and 7F ₂ according to the present invention are used in a hydraulic clutch type transmission equipped with the clutch hydraulic pressure gradually increasing mechanism as described above, as shown in FIG. , the relationship between the time t from the time of switching the position of the switching valve that switches and controls the supply and discharge of hydraulic pressure to multiple hydraulic clutches and the hydraulic pressure P established in the oil supply circuit for the hydraulic clutches is such that the initial hydraulic pressure P ₁ is established in a relatively short time t ₁ . is obtained, and the oil pressure P gradually rises from the initial oil pressure P ₁ to the normal oil pressure P _2. However, as shown in FIG. The characteristic previously observed in relation to the generated transmission torque T, that is, the transmission torque T rapidly increases from zero to a certain value T ₁ at the time t ₁ when the initial oil pressure P ₁ is established, is shown by curve C _b . According to the hydraulic clutches 7F ₁ and 7F ₂ of the present invention, since hydraulic pressure is supplied through the throttle oil passage 20, the initial hydraulic pressure P ₁ is reduced to the piston 13.
does not act directly, and the spring force of the disc spring 17 counteracts the hydraulic pressure that is gradually applied through the throttle oil passage 20, causing the disc spring 17 to flex gently.
As shown by the curve C _a , a torque generation characteristic that gradually increases from zero is obtained. And especially,
When shifting down from the forward 2nd gear, which operates the F ₂ hydraulic clutch 7F ₂ , to the forward 1st gear, which operates the F ₁ hydraulic clutch 7F ₁ , by switching the circuit with the switching valve, At this time, since the oil drain from the oil chamber 16 of the F ₂ hydraulic clutch 7F ₂ is first performed via the throttling oil passage 20, the initial oil pressure of the F ₁ hydraulic clutch 7F _{1 is}
At the time t ₁ when P ₁ acts, the disk spring 17 of the F ₂ hydraulic clutch 7F ₂ has not fully returned from the compressed state, and some residual torque exists in the F ₂ hydraulic clutch 7F ₂ . Therefore, _F1 hydraulic clutch _7F1 has an initial hydraulic pressure.
Both hydraulic clutches 7F ₁ and 7F ₂ generate a small transmission torque for a short period of time from the time t ₁ when P ₁ acts, resulting in an extremely smooth deceleration feeling.

As described above, the multi-plate hydraulic clutch for a hydraulic clutch type transmission according to the present invention is equipped with a disc spring 17 that receives the friction plates 9 and the mating plates 10 from the opposite side of the piston 13 for actuating the clutch. , an oil passage 19 that communicates a hydraulic oil passage 18 formed in the clutch housing 6 with an oil chamber 16 behind the piston 13 is passed through the piston 13, and the piston 13 is connected between the friction plate 9 and the mating plate 10. The hydraulic oil passage 18 is arranged so that it is blocked by the clutch housing 6 when the clutch housing 6 is advanced until they are brought into close contact with each other.
A throttle oil passage 20 that constantly communicates with the oil chamber 16
is provided between the piston 13 and the clutch housing 6, and as described in detail in the description of the operation of the embodiment, the oil passage 19 is provided until the friction plate 9 and the mating plate 10 come into close contact with each other. The subsequent throttling oil passage 20 without sacrificing clutch engagement time with a high proportion of oil supply.
By gradually deflecting the disc spring 17 by gradually supplying oil through the disc spring 17, the transmission torque generated in the multi-disc hydraulic clutch is gradually increased. The effect of preventing the occurrence of shock when starting or accelerating in the forward direction has been greatly improved. Furthermore, when the multi-disc hydraulic clutch of this invention is used in a hydraulic clutch type transmission equipped with a clutch action hydraulic pressure increasing mechanism, as described in detail earlier, the initial hydraulic pressure by the hydraulic pressure increasing mechanism is This is avoided by supplying hydraulic pressure through the throttle oil passage 20, and the transmitted torque is gradually increased by the gradual deflection of the disc spring 17 due to the gradual hydraulic action.More particularly, When downshifting a hydraulic clutch type transmission, oil is first drained from the hydraulic clutch of the higher gear via the throttle oil passage 20, and at the same time the hydraulic clutch of the lower gear is supplied with oil via the oil passage 19. Since the state in which torque can be generated quickly is brought about, both of the above-mentioned hydraulic clutches generate a weak transmitted torque, resulting in the effect that a smooth deceleration feeling can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view showing the main parts of a hydraulic clutch type transmission equipped with an embodiment of this invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view of the
The enlarged vertical sectional side view, which shows a part of the figure enlarged, and FIGS. 4 and 5 are schematic graphs for explaining the operation, respectively. 1...Forward gear shift shaft, 3F ₁ ... _F1 gear, 3F ₂ ...
...F ₂ gear, 6...clutch housing, 7F ₁ ...
...F ₁ hydraulic clutch, 7F ₂ ...F ₂ hydraulic clutch,
9...Friction plate, 10...Mating plate, 12...Pressure receiving plate, 13...Piston, 16...Oil chamber, 17...
Belleville spring, 18F ₁ , 18F ₂ ... Hydraulic oil passage, 18
a...Slot hole, 19...Oil passage, 19a...Slot hole,
20... Squeezing oil passage.

Claims (1)

[Scope of utility model registration request] A disc spring is installed inside to receive the friction plate and the mating plate group from the opposite side of the piston for actuating the clutch.
This is a multi-plate hydraulic clutch for a hydraulic clutch type transmission, and the piston is connected to a friction plate and an oil passage formed in the clutch housing that communicates with an oil chamber behind the piston. A throttle oil passage is provided so as to be blocked by the clutch housing when the mating plates are moved forward until the mating plates are brought into substantially close contact with each other, and the throttle oil passage constantly communicates the hydraulic oil passage with the oil chamber.
A multi-plate hydraulic clutch characterized by being installed between the piston and clutch housing.