JPS61197827A - Drag torque prevention device of hydraulic clutch - Google Patents

Abstract

PURPOSE:To prevent drag torque surely by installing an accumulator on a clutch circuit to a clutch pressurizing chamber and connecting a drain port of the accumulator to a clutch multiplate lubricating circuit. CONSTITUTION:An accumulator 21 is mounted to an accumulator circuit 20 and a piston is provided with a tapered face 27 which becomes thinner to a pressure storage chamber 26 side, and one end of an escape hole 28 is opened on the tapered face 27 and the other end of the hole 28 is connected to a drain 29. The escape hole 28 can be closed by a movable piston 24. Then, oil is not flowed to a lubricating circuit when clutch pressure is off and generation of drag torque can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is applicable to a drag torque prevention device for a wet multi-disc hydraulic clutch used in construction machinery, agricultural machinery, etc.

(Prior art) Conventionally, for example, clutch circuits 1 and 11 as shown in FIG. P
The t circuit 2 is separate, and oil constantly flows through the lubrication circuit 2, which causes drag when the clutch is turned off. That is, in FIG. 3, the clutch circuit 1 is connected from the discharge port of the pump 3 via the switching valve 4 to the input side cover 5 and the dark pressurizing chamber 7 of the annular piston 6. Also, a plurality of plates 8 that are slidably supported on the cover 5 and a plurality of disks 10 that are slidably supported on the output side hub 9 are arranged alternately, and are moved by a stopper ring 11. The amount is ill limited.

The lubrication circuit 2 is provided in a shaft portion 12 that is integrated with the cover 5, and one end is connected to the pump 3 via a throttle or the like, and a nozzle 13 at the other end opens toward the inner surface of the hub 9. Plate 8 and disk 1 are inserted through the plurality of oil holes 14 provided.
It is possible to constantly supply lubricating oil to the zero friction parts.

According to [i in Fig. 3], since oil is constantly flowing in the RA lubricating circuit, the area between the plate 8 and the disk 10 is filled with lubricating oil even when the clutch is off, and the plate 8 is Therefore, the disk 10 is subjected to rotational force (drag torque), causing a problem of creep phenomenon. Some had separate brakes to prevent creep.

(Object of the invention) The present invention utilizes the drain of the accumulator attached to the clutch circuit for the rlIW# circuit, and when the clutch is off!
IIW4 Oil is reduced to zero to prevent drag torque, a large amount of oil is flowed only during engagement when lubricating oil is required, and after engagement is completed, excess oil is prevented from flowing and clutch pressure is reliably maintained. , which attempts to solve the above-mentioned conventional problems.

(Structure of the Invention) The present invention includes an accumulator attached to the clutch circuit leading from the pump to the clutch pressurizing chamber via the switching valve, and the drain port of the accumulator has multiple clutch plates! This is a drag torque prevention device for a hydraulic clutch, characterized in that it is connected to a single slip circuit.

(Example) In FIG. 1, an accumulator 21 is attached to an accumulator circuit 20 branched from a clutch circuit 1.

This accumulator 21 includes a fixed taper valve 22, a closed cylinder 23, a movable piston 24, and a compression coil spring 25.

The piston 22 has a tapered surface 27 in its intermediate portion that becomes narrower toward the pressure accumulation chamber 26 side, one end of a relief hole 28 opens in the tapered surface 27, and the other end of the relief hole 28 is connected to a drain 29. Due to the elasticity of the spring 25 compressed between the flange 30 of the e-ston 22 and the movable piston 24,
The movable piston 24 is urged toward the pressure accumulation chamber 26 and maintains the standby position shown in FIG. The movable piston 24 has a tapered surface 2 on the inside.
7, so that the relief hole 28 can be opened by the movable piston 24.

Next, the operation will be explained. First, in the clutch-off state (range a in FIG. 2), no oil flows into the clutch circuit 1, so the amount of lubricating oil is also zero. Next, when the clutch is turned on by actuation of the switching valve 4, oil flows through the clutch circuit 1 to the pressurizing chamber of the clutch piston (range b in FIG. 2). This current flows to the 1lIW1 circuit 2 through the gap between the pistons 22 and 24, the relief hole 28, and the drain 29. When the clutch piston stops, the clutch pressure increases (range C in Figure 2). At this time, the movable piston 24 moves to the right against the elasticity of the spring 25, and the gap between both pistons 22 and 24 increases, so the increase in oil pressure becomes gradual, while the drain 2
The amount of lubricating oil sent to the rRW1 circuit 2 via 9 also increases.

Piston 24 moves further to the right in range d), piston 2
When the taper inner surface 32 of the piston 24 coincides with the taper surface 27 of the piston 2, the relief hole 28 is closed, the amount of lubricating oil becomes zero, and the clutch pressure rapidly increases to the set value (regulator pressure).

(Effects of the Invention) As described above, according to the present invention, since oil is not flowed into the lubricating circuit when the clutch pressure is turned off (at the time of release), generation of drag torque can be reliably prevented. Mataki: Since the drain from the tom regulator is used in the lubrication circuit, it is linked to the operation of the tom regulator and the amount suitable for the clutch engagement stroke is used. Can provide vl lubricant, 11! The largest amount of oil is supplied during clutch engagement, where a large amount of frictional heat is generated, allowing for effective cooling, and after clutch engagement is completed, the supply of lubricating oil is stopped, reducing the clutch pressure. It has the advantage of being able to be held securely. Furthermore, if an accumulator with a needle-type piston as shown in Fig. 1 is adopted,
Although it is compact, the eight pressure accumulation peaks are large, making it easy to gently adjust the rise of hydraulic pressure to the clutch.

[Brief explanation of the drawing]

Fig. 1 is a schematic longitudinal cross-sectional view of the drag torque prevention device according to the present invention, Fig. 2 is a graph showing the relationship between clutch pressure, lubricating oil amount, and time, and Fig. 3 is a partial vertical cross-sectional view showing the conventional clutch structure. be. 1...Clutch circuit, 2...R8 circulation circuit, 3...Pump, 4...Switching valve, 7...Clutch pressurizing chamber, 21...Accumulator, 29...Drain

Claims (2)

[Claims] (1) A drag torque prevention device for a hydraulic clutch, characterized in that an accumulator is attached to a clutch circuit leading from a pump to a clutch pressurizing chamber via a switching valve, and a drain port of the accumulator is connected to a clutch multi-plate lubrication circuit. (2) The accumulator has a closed cylinder having a taper valve with a relief hole, a movable piston fitted to the taper valve, and a spring urging the movable piston toward the pressure accumulation chamber,
A drag torque prevention device for a hydraulic clutch according to claim 1, wherein the movable piston closes the relief hole after the clutch is connected.