JPS6215060Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boost control valve that slowly operates a hydraulic clutch.

For example, when connecting a hydraulic clutch in a tractor, etc., if the pressure of the hydraulic oil increases rapidly, torque will be transmitted rapidly from the prime mover to the driven shaft, resulting in poor riding comfort and operability, and damage to the torque transmission system. Harmful effects may occur.

For this reason, a pressure increase control valve 1 as shown in FIG. 1 is provided in order to gently control the pressure increase when the hydraulic clutch is engaged.

Briefly, hydraulic oil is supplied from the hydraulic pump 2 to the primary passage 4 through the switching valve 3, passes through the throttle passage 6 bored in the plunger 5, the balance chamber 7, and the pilot passage 8, and then enters the pilot chamber 9. When the water flows into the air, the piston 11 is moved in the direction of arrow 12 against the force of the spring 10.

At this time, since hydraulic oil flows from the primary passage 4 to the balance chamber 7, a pressure difference is created before and after the throttle passage 6, and this pressure difference causes the plunger 5 to move in the direction of arrow 14 against the spring 13. . Primary passages 4 and 2 that were blocked by the side of plunger 5
Since it communicates with the downstream passage 15, a portion of the hydraulic oil from the primary passage 4 is immediately discharged from the secondary passage 15 to the oil tank 16, causing a sudden increase in hydraulic oil pressure supplied to the hydraulic clutch 17. rise is avoided.

As the pressure of the hydraulic oil supplied to the primary passage 4 increases, the pressure in the pilot chamber 9 also increases, causing the piston 11 to move against the spring 10. When the piston rod 18 comes into contact with the stopper 20 in the spring chamber 19, the flow of hydraulic oil into the pilot chamber 9 is stopped, so that no flow passes through the throttle passage 6. Therefore, the pressure difference that had been occurring before and after the throttle passage 6 becomes 0, and the plunger 5
is pushed in the direction of arrow 21 by the spring 13, and communication between the primary passage 4 and the secondary passage 15 is cut off.

Therefore, the pressure in the primary passage 4 is released from pressure control by the boost control valve 1, and when all the hydraulic oil is directly supplied to the hydraulic clutch 17 via the supply pipe 22, the pressure inside the clutch reaches the desired level. It will rise and the connection will be completed.

In such a boost control valve 1, the operating parts of the plunger 5 and the piston 11 are provided separately in one casing, so the operating holes need to be machined in two places, and the casing itself can be made smaller. It's difficult.

In addition, the boost control valve 1 is mounted in a sanderch-type mounting manner, as shown in FIG. In the case where the boost control valve 1 is not required as shown in Figure b, the length of the connecting pipe 25 from the permanent pipe 24 to the clutch switching valve 3 must be changed. However, there are disadvantages such as the need to prepare connecting pipes of different lengths.

This invention was developed to solve the above-mentioned problems, and it aims to reduce the size of the boost control valve itself, reduce the number of machining parts on the casing, and also improve the mounting of the boost control valve on the main body of the piping system. An object of the present invention is to provide a boost control valve for a hydraulic clutch that can be included in, for example, a transmission case without changing the system.

The feature is that a plunger that communicates with and shuts off the primary passage and the secondary passage bored in the casing is disposed inside the casing so as to be freely displaceable by being biased by a spring.
A throttle passage is bored at the tip of the plunger to communicate a balance chamber carved in the plunger with the primary passage, and a piston, which can be freely displaced by being biased by a spring in the balance chamber, is connected to the plunger. The pressure boost control valve for the hydraulic clutch is interposed concentrically with the hydraulic clutch.

The present invention will be described in detail below with reference to the embodiments.

Figure 3 shows the pressure boost control valve 3 for a hydraulic clutch according to the present invention.
FIG.

For example, a primary passage 33 is bored inside a threaded portion 32 carved on the outer periphery of one end 31a of a cylindrical casing 31, and this primary passage 3
As shown in FIG. 4, an appropriate number of secondary passages 34 are bored in the side surface of the casing 31 adjacent to the secondary passages 34.

The primary passage 33 and the secondary passage 34 are connected to the plunger 3 which is biased by a spring 36 interposed in a spring chamber 35 in the casing 31.
At 7, communication and interruption are established at a tapered portion 31b within the casing 31.

Note that this spring 36 is connected to the primary side passage 33.
When the pressures between the plunger 37 and the balance chamber 38 (to be described later) become equal, the tip 37a of the plunger 37 is pressed so as to come into contact with the tapered portion 31b of the casing 31.

A throttle passage 39 is bored in the tip 37a of the plunger 37, which communicates a balance chamber 38 carved in the plunger 37 with the primary passage 33. A piston 40 is disposed concentrically within the balance chamber 38 and is displaced by sliding on the inner surface 37b of the plunger 37.
5 is biased toward the throttle passage 39 by a spring 41 interposed inside the throttle passage 39 .

Note that this spring 41 is connected to the balance chamber 38
until the pressure inside the piston 40 reaches a certain value or more.
It is something that keeps it still.

The rear end of the spring chamber 35 of the casing 31 is closed by a cover body 43 with a seal 42 interposed therebetween, which allows the springs 36 and 41 to be closed.
A rear end 44a of the piston rod 44 holds one end and protrudes from the back of the piston 40.
are in contact with each other to prevent movement of the piston 40.

A hole 45 is formed in the casing 31 through which the spring chamber 35 communicates with the outside air.
4 is for discharging the air in the spring chamber 35.

Since the present invention is configured as described above, it can be operated as follows.

When the switching valve (not shown) is switched, the primary passage 3
3 and the pressure in the hydraulic clutch increases to P1 (see FIG. 5) and the piston in the clutch begins to move. When time T1 has elapsed and the piston has finished moving, the pressure within the clutch continues to rise and torque begins to be transmitted.

At this time, from the primary passage 33 to the balance chamber 38
Since the hydraulic oil flows to the throttle passage 39, a pressure difference is generated before and after the throttle passage 39. When the plunger 37 moves in the direction of arrow 47 against the spring 36 due to this pressure difference, the tip 37a of the plunger 37 separates from the tapered portion 31b. Therefore, a portion of the hydraulic oil flows out from the primary passage 33 to the secondary passage 34 and is discharged into an oil tank (not shown).

Here, the pressure in the balance chamber 38 is equal to that of the spring 4.
The pressure corresponds to the spring force of 1, and the balance chamber 3
The pressure in the primary passage 33, that is, the pressure in the hydraulic clutch, is adjusted by moving the plunger 37 so that the sum of the pressure at 8 and the spring force of the spring 36 and the pressure in the primary passage 33 are balanced.

At this time, the pressure in the primary passage 33 is higher than the pressure in the balance chamber 38 by the spring force of the spring 36, that is, the pressure balances the sum of the spring force of the spring 41 and the spring force of the spring 36.

As a result, the piston 40 moves and the spring 4
As the amount of deflection of piston 1 increases, the pressure in primary passage 33 also increases to pressure P2 shown in FIG. 5 in accordance with the movement of piston 40.

In addition, since the moving speed of the piston 40 is determined by the flow rate flowing into the balance chamber 38, the fifth speed can be increased by changing the size of the throttle of the throttle passage 39.
As shown in the figure, the pressure rise gradient of the hydraulic clutch is A1
〜A3 can be set arbitrarily by adjusting the spring constant of the spring 41 and the degree of restriction of the restriction passage 39.

Next, as the piston 40 continues to move and the piston rod 44 comes into contact with the lid 43 at the end of the spring chamber 35, the flow of hydraulic oil into the balance chamber 38 is stopped and the flow passing through the throttle passage 39 is eliminated. The pressure difference that occurred before and after the passage 39 is now 0.
Therefore, the pressures in the primary passage 33 and the balance chamber 38 become equal. Therefore, the plunger 37 is pushed in the direction of arrow 48 by the spring 36.
When the tip 37a comes into contact with the tapered part 31b,
Communication between the primary passage 33 and the secondary passage 34 is cut off. At time T2 during this period, for example, the fifth
As shown by line A3 in the figure, the pressure of the hydraulic clutch is P
When the rotation speed increases to 2, the torque transmission rotation speed also increases as shown in the figure.

Note that the length of this time T2 can be arbitrarily set depending on the size of the throttle of the throttle passage 39 and the stroke amount of the piston 40.

At the time when the communication between both passages is cut off in this way, the pressure in the primary passage 33 is reduced to this pressure increase control valve 3.
The pressure of the hydraulic clutch is released from the pressure control by
It rises to 3.

In this way, the hydraulic clutch P2 (P2
a, P2b, P2c), thereby avoiding sudden engagement of the clutch.

The boost control valve 30 described above is extremely compact, and can be easily installed, for example, in a transmission case attached to the lower part of the main body using the threaded portion 32 cut at the tip of the casing 31, and can be easily attached to the secondary side. Since the hydraulic oil discharged from the passage 34 can be directly dropped into the oil reservoir of the transmission case, there is no need for any piping for this purpose.

As explained in detail above, the present invention allows the plunger, which communicates and cuts off the primary passage and the secondary passage bored in the casing, to be freely displaced by biasing the plunger inside the casing with a spring. A throttle passage is provided at the tip of the plunger to communicate the balance chamber carved in the plunger with the primary passage, and a piston that is freely displaceable by biasing with a spring is provided in the balance chamber. Since the pressure increase control valve for the hydraulic clutch is interposed concentrically with the plunger, the pressure increase of the hydraulic clutch can be made as gradual as desired, and the pressure increase control valve itself can be made smaller. It can be installed in any desired position, such as inside the body.

In addition, since the plunger and the piston are interposed concentrically, the number of holes to be drilled in the casing is reduced, and the number of manufacturing steps can be reduced.

In addition, the boost control valve can be attached to the main body without changing the length of the connecting piping to the permanently installed piping system as shown in Figure 2 a and b, and can be attached or removed as necessary. This can be done separately while maintaining the switching valve and its connecting piping. Furthermore, when installed inside the mission case, the discharge piping of the secondary passage becomes unnecessary.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional pressure boost control valve for a hydraulic clutch, Figures 2 a and b are comparative views of the connection to the permanent piping system in the main body, and Figure 3 is a cross section of the pressure boost control valve for a hydraulic clutch according to the present invention. Fig. 4 is - of Fig. 3.
The line sectional view and FIG. 5 are a characteristic diagram showing the relationship between the passage of time and the clutch internal pressure when used in a hydraulic clutch circuit, and a characteristic diagram showing the relationship between the passage of time and the clutch rotation speed. 30... Boost control valve, 31... Casing, 3
3...Primary side passage, 34...Secondary side passage, 36...
...Spring, 37...Plunger, 37a...
Tip, 38...Balance chamber, 39...Aperture passage,
40...piston, 41...spring.

Claims (1)

[Scope of Claim for Utility Model Registration] A plunger that communicates and blocks communication between a primary passage and a secondary passage bored in a casing is disposed within the casing so as to be freely displaceable by being biased by a spring, A throttle passage is bored at the tip of the plunger to communicate a balance chamber carved in the plunger with the primary passage, and the piston, which is freely displaceable by being biased by a spring in the balance chamber, is connected to the primary passage. A boost control valve for a hydraulic clutch, characterized in that it is interposed concentrically with a plunger.